Valve devices for controlling flow of intake air Number:7,137,614 from the United States Patent and Trademark Office (PTO) owispatent

Title: Valve devices for controlling flow of intake air

Abstract: A valve device controls a flow of intake air within a surge tank connected to an engine. The surge tank is divided into a plurality of tank chambers by a partition wall disposed within the surge tank. The valve devices include a valve body and a valve member. The valve body has a frame mounted within a communication opening defined within the partition wall. The valve member is rotatably mounted to the valve body in order to open and close a frame opening defined in the frame. A motor is coupled to the valve member in order to rotate the valve member. The motor includes a stator molded integrally with the valve body.

Patent Number: 7,137,614 Issued on 11/21/2006 to Masui,   et al.

---

Inventors:	Masui; Toshiyuki (Aichi-ken, JP), Ishikawa; Katsuji (Aichi-ken, JP)
Assignee:	Aisan Kogyo Kabushiki Kaisha (Obu, JP)
Appl. No.:	10/963,751
Filed:	October 14, 2004

---

Foreign Application Priority Data

---

Oct 15, 2003 [JP]			2003-355022
Oct 15, 2003 [JP]			2003-355026
Oct 22, 2003 [JP]			2003-362330

Current U.S. Class:	251/129.11 ; 123/337; 251/305
Current International Class:	F16K 31/02 (20060101)
Field of Search:	251/305,306,129.11 123/337,361,399 310/43,254

---

References Cited [Referenced By]

---

U.S. Patent Documents

	5884898		March 1999		Miyairi
	6067961		May 2000		Kato
	6497245		December 2002		Torii
	6742496		June 2004		Hattori et al.

Foreign Patent Documents

	2002018170		Jan., 2002		JP

Primary Examiner: Look; Edward K.
Assistant Examiner: Fristoe, Jr.; John K.
Attorney, Agent or Firm: Dennison, Schultz & MacDonald

---

Claims

---

The invention claimed is:

1. A valve device for controlling a flow of an intake air within a surge tank connected to an engine, wherein the surge tank is divided into a plurality of tank chambers by a partition wall disposed within the surge tank, the valve device comprising: a valve body having a frame mounted within a communication opening defined in the partition wall, wherein the valve body includes a frame defining a frame opening; a valve member rotatably mounted to the valve body in order to open and close the frame opening; a motor coupled to the valve member and arranged and constructed to rotate the valve member, wherein the motor includes a stator molded integrally with the valve body; a first rotary shaft connected to a first end of the valve member on a side of the motor; wherein the frame includes a first frame portion on the side of the motor and a first support portion formed on the first frame portion and having an outer diameter; wherein the first portion has a thickness substantially equal to or greater than the outer diameter of the first support portion; and wherein the first frame portion further includes a thickness reduced portion.

2. A valve device for controlling a flow of an intake air within a surge tank connected to an engine, wherein the surge tank is divided into a plurality of tank chambers by a partition wall disposed within the surge tank, the valve device comprising: a valve body having a frame mounted within a communication opening defined in the partition wall, wherein the valve body includes a frame defining a frame opening; a valve member rotatably mounted to the valve body in order to open and close the frame opening; a motor coupled to the valve member and arranged and constructed to rotate the valve member, wherein the motor includes a stator molded integrally with the valve body; a second rotary shaft connected to a second end of the valve member on a side opposite to the motor, and wherein the frame further includes a second frame portion on the side opposite to the motor, and a second support portion is formed on the second frame portion in order to rotatably support the second rotary shaft, and wherein the second frame portion is engageable with a projection formed on the partition wall along the communication opening in a position opposing the second frame portion, and wherein the projection has a thickness greater than a typical thickness of the partition wall.

3. The valve device as in claim 2, wherein the projection has a width substantially equal to the width of the second frame portion.

4. A valve device for controlling a flow of an intake air within a surge tank connected to an engine, wherein the surge tank is divided into a plurality of tank chambers by a partition wall disposed within the surge tank, the valve device comprising: a valve body having a frame mounted within a communication opening defined in the partition wall, wherein the valve body includes a frame defining a frame opening; a valve member rotatably mounted to the valve body in order to open and close the frame opening; a motor coupled to the valve member and arranged and constructed to rotate the valve member, wherein the motor includes a stator molded integrally with the valve body; wherein the valve body further includes a motor housing formed integrally with the valve body, and a stator is integrated within the motor housing; wherein the motor further includes a rotor shaft coupled to the valve member and disposed within the motor housing; wherein the valve member rotates from a first position to a second position as the motor is energized to produce a rotational torque for rotating the rotor shaft in a first direction; wherein the valve device further includes a valve returning device arranged and constructed to return the valve member from the second position to the first position when the motor is de-energized; wherein the valve returning device is disposed within the motor housing; and wherein the valve returning device comprises: a coil spring having a first end and a second end, a first spring support member arranged and constructed to connect the first end of the coil spring to the rotor shaft; and a second spring support member arranged and constructed to connect the second end of the coil spring to the motor housing, wherein the coil spring applies a rotational torque to the rotor shaft in a direction opposite to the first direction, and a cover mounted to the motor housing in order to close a housing opening formed in the motor housing, and wherein the second spring support member is formed on an inner wall of the cover.

5. The valve device as in claim 4, wherein the housing opening is defined in the motor housing in order to insert the first spring support member and the coil spring into the motor housing.

6. The valve device as in claim 5, wherein the motor housing includes a tubular portion that includes the housing opening, and wherein the cover is closely fitted into the tubular portion.

7. The valve device as in claim 6, wherein the cover has a substantially cylindrical tubular configuration with an open end and a closed end, wherein a positioning projection and a corresponding positioning recess for engaging the positioning projection are formed on one and the other of the cover and the tubular portion of the motor housing in order to position the cover relative to the tubular portion in a circumferential direction.

8. The valve device as in claim 4, wherein: the rotor shaft has an end portion having a non-circular cross section, and the first spring support member has a fitting hole having a corresponding non-circular configuration conforming to the cross sectional configuration of the end portion of the rotor shaft, wherein the end portion of the rotor shaft is press-fitted into the fitting hole of the first spring support member, and wherein a plurality of fitting projections are formed on an inner periphery of the fitting hole and extend in a fitting direction of the end portion of the rotor shaft, and wherein the fitting hole includes at least one corner portion; and wherein a substantially semi-circular recess is formed in the first spring support member around the corner portion to extend parallel to the fitting projections.

9. The valve device as in claim 8, wherein the fining hole has a substantially semi-circular configuration with a curved portion and a linear portion, wherein the fitting projections are formed along the curved portion, and wherein a semi-circular recess is formed around each end of the linear portion.

10. The valve device as in claim 4, wherein the first spring support member further includes a first stopper portion, and the second spring support member further includes a second stopper portion, wherein the first stopper portion and the second stopper portion contact with each other to inhibit further movement of the valve member when the valve member returns to the first position by the biasing force of the coil spring.

11. The valve device as in claim 4, further including a retainer and a positioning protrusion formed on the inner wall of the cover, wherein the retainer is arranged and constructed to retain engagement of the second end of the coil spring with the second spring support member, and the positioning protrusion is arranged and constructed to support the coil spring in a position axially aligned with the rotor shaft.

12. A valve device for controlling a flow of an intake air within a surge tank connected to an engine, wherein the surge tank is divided into a plurality of tank chambers by a partition wall disposed within the surge tank, the valve device comprising: a valve body having a frame mounted within a communication opening defined in the partition wall, wherein the valve body includes a frame defining a frame opening; a valve member rotatably mounted to the valve body in order to open and close the frame opening; a motor coupled to the valve member and arranged and constructed to rotate the valve member, a motor housing arranged and constructed to receive the motor therein, wherein the motor includes a rotor shaft coupled to the valve member, so that the valve member rotates from a first position to a second position when a current is supplied to the motor to produce a rotational torque for rotating the rotor shaft in a first direction, and wherein the valve device further includes a valve returning device arranged and constructed to return the valve member from the second position to the first position when the current is no longer supplied to the motor, and wherein the valve returning device is disposed within the motor housing, wherein the valve returning device comprises: a coil spring having a first end and a second end, a first spring support member arranged and constructed to connect the first end of the coil spring to the rotor shaft; and a second spring support member arranged and constructed to connect the second end of the coil spring to the motor housing, so that the coil spring applies a rotational torque to the rotor shaft in a direction opposite to the first direction, and a cover mounted to the motor housing in order to close a housing opening formed in the motor housing, wherein the second spring support member is formed on an inner wall of the cover.

13. The valve device as in claim 12, wherein the housing opening is defined in the motor housing in order to insert the first spring support member and the coil spring into the motor housing.

14. The valve device as in claim 12, wherein the first spring support member includes a first stopper portion, and the second spring support member includes a second stopper portion, so that the first stopper portion and the second stopper portion contact with each other to limit further movement of the valve member when the valve member returns to the first position by the biasing force of the coil spring.

15. The valve device as in claim 12, further including a retainer and a positioning protrusion formed on the inner wall of the cover, wherein the retainer is arranged and constructed to retain engagement of the second end of the coil spring with the second spring support member, and the positioning protrusion is arranged and constructed to support the coil spring in a position axially aligned with the rotor shaft.

16. A valve device for controlling a flow of an intake air within a surge tank connected to an engine, wherein the surge tank is divided into a plurality of tank chambers by a partition wall disposed within the surge tank, the valve device comprising: a valve body having a frame mounted within a communication opening defined in the partition wall, wherein the valve body includes a frame defining a frame opening; a valve member rotatably mounted to the valve body in order to open and close the frame opening; a motor coupled to the valve member and arranged and constructed to rotate the valve member, and a motor housing arranged and constructed to receive the motor therein, wherein the motor includes a rotor shaft coupled to the valve member, so that the valve member rotates from a first position to a second position when a current is supplied to the motor to produce a rotational torque for rotating the rotor shaft in a first direction, and wherein the valve device further includes a valve returning device arranged and constructed to return the valve member from the second position to the first position when the current is no longer supplied to the motor, and wherein the valve returning device is disposed within the motor housing, and the rotor shaft has an end portion having a non-circular cross section, and the first spring support member has a fitting hole having a non-circular configuration conforming to the cross sectional configuration of the end portion of the rotor shaft, wherein the end portion of the rotor shaft is press-fitted into the fitting hole of the first spring support member, and wherein a plurality of fining projections are formed on an inner periphery of the fitting hole and extend in a fitting direction of the end portion of the rotor shaft, and wherein the fitting hole includes at least one corner portion; and wherein a substantially semi-circular recess is formed in the first spring support member around the corner portion to extend parallel to the fitting projections.

17. The valve device as in claim 16, wherein the fitting hole has a substantially semi-circular configuration with a curved portion and a linear portion, wherein the fitting projections are formed along the curved portion, and wherein a pair of semi-circular recesses are formed around both ends of the linear portion.

---

Description

---

This application claims priority to Japanese patent application serial numbers 2003-355022, 2003-355026 and 2003-362330, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to valve devices for controlling the flow of intake air supplied to internal combustion engines, in particular, multicylinder internal combustion engines.

2. Description of the Related Art

In order to control the flow of intake air of multicylinder internal combustion engines, variable intake air systems having valve devices have been used. In particular, in order to shift nodes of acoustic oscillations the intake air may produce and to increase an effective intake-air column length, variable intake air systems known as "acoustic control induction systems (ACIS)" have been proposed.

Japanese Laid-Open Patent Publication No. 2000-55200 teaches a valve device for controlling the flow of intake air and for use with an acoustic control induction system. The valve device includes a valve body, a valve member, and an actuator. The valve body is made of resin and has a frame portion fittable into an opening defined within a partition wall. The partition wall is disposed within a tank chamber of a surge tank of an internal combustion engine in order to divide the tank chamber into sub-chambers. The valve member is rotatably mounted on the valve body in order to open and close an opening defined by the frame portion of the valve body. The valve member operates in order to permit and interrupt communication between the sub-chambers. The actuator serves to rotate the valve member.

In the above publication, a diaphragm-type, negative-pressure control device is typically incorporated as the actuator. However, this type of actuator involves various components and tubes, complicating assembly and increasing manufacturing costs.

SUMMARY OF THE INVENTION

It is accordingly an object of the present invention to teach improved and simplified valve devices for controlling the flow of intake air supplied to a multicylinder internal combustion engines.

According to one aspect of the present teachings, valve devices are taught that control the flow of an intake air within a surge tank connected to an engine. The surge tank is divided into a plurality of tank chambers by a partition wall disposed within the surge tank. The valve devices include a valve body and a valve member. The valve body has a frame mounted within a communication opening defined in the partition wall. The valve member is rotatably mounted to the valve body in order to open and close a frame opening defined within the frame. A motor is coupled to the valve member in order to rotate the valve member. The motor includes a stator molded integrally with the valve body. For example, the stator may include a stator core and a stator coil.

Therefore, a fixing device or a mounting device, such as screws, for mounting the stator is not necessary. In addition, a separate motor housing to which the stator is mounted is not necessary. Therefore, the number of parts and the number of assembly steps of the valve device can be reduced or minimized. As a result, the manufacturing costs of the valve devices can be reduced relative to conventional valve devices. In addition, the use of fewer parts may allow the valve devices to have a lightweight construction.

Preferably, the valve body is made of resin and the stator is molded integrally within the valve body by an insertion molding process.

Preferably, the valve body further includes an integral motor housing formed with the frame. The stator is molded within the integrated motor housing.

In another aspect of the present teachings, the valve devices further include a first rotary shaft connected to a first end of the valve member on the side of the valve member nearest to the motor. The frame includes a first frame portion on the side of the motor. A first support portion is formed comprising an outer diameter on the first frame portion. The first frame portion has a thickness substantially equal to or greater than the outer diameter of the first support portion.

Therefore, the supporting strength of the first support portion as well as the strength of the entire frame can be improved.

Preferably, the first frame portion on the side of the motor further includes a thickness reduced portion. Therefore, it is possible to design a mold for molding the frame such that the flow of the resin in the region of the first frame portion becomes uniform. As a result, potential molded in stress and strain, evidenced in part by characteristics such as surface sink due to heat contraction, can be reduced to improve both the quality and the accuracy in the resultant size of the frame.

Preferably, the motor further includes a rotor having a rotor shaft. The first rotary shaft is the rotor shaft.

In another aspect of the present teachings, the valve devices further include a second rotary shaft connected to a second end of the valve member on the side opposite to the motor. The frame further includes a second frame portion on the side opposite to the motor. A second support portion is formed in the second frame portion in order to rotatably support the second rotary shaft. The second frame portion is engageable with a projection formed on the partition wall along the communication opening in a position directly opposing the second frame portion. The projection has a thickness greater than the thickness of the partition wall.

The second frame portion can therefore be stably supported by the projection of the partition wall.

Preferably, the projection has a width substantially equal to the width of the second frame portion. Therefore the supporting strength of the second frame by the projection can be improved and any possible stress applied to the projection by the intake air due to pulsation of the intake air can be effectively relaxed.

In another aspect of the present teachings, valve devices are taught that include a valve body, a valve member, a motor and a motor housing. The valve body has a frame mounted within a communication opening defined in a partition wall disposed within a surge tank. The valve body includes a frame defining a frame opening. The valve member is rotatably mounted to the valve body in order to open and close the frame opening. The motor is coupled to the valve member in order to rotate the valve member and is received within the motor housing. The motor includes a rotor shaft directly coupled to the valve member. The valve member rotates from a first position to a second position as the motor is energized. The energized motor produces a rotational torque for rotating the rotor shaft in a first direction. The valve devices further include a valve returning device that serves to return the valve member from the second position to the first position when the motor is de-energized. The valve returning device is disposed within the motor housing. Preferably, the motor housing is formed integrally with the valve body.

Because the rotor shaft of the motor is directly coupled to the valve member, no separate linking mechanisms or speed reduction mechanisms are interposed between the motor and the valve member. Therefore, the construction of the valve device can be simplified and contained within a relatively compact overall space. In addition, because the valve returning device is disposed within the motor housing, the valve returning device may be sheltered from the environment outside of the motor housing. Consequently, no additional housing is necessary for the valve returning device. Therefore, the valve device may also be compact in size in this respect.

In another aspect of the present teachings, the valve returning device includes a coil spring, a first spring support member, and a second spring support member. The first spring support member serves to connect a first end of the coil spring to the rotor shaft. The second spring support member serves to connect a second end of the coil spring to the motor housing, so that the coil spring applies a rotational torque to the rotor shaft in a direction opposite to the first direction. A cover is mounted to the motor housing in order to close and seal a housing opening formed in the motor housing. The second spring support member is formed on an inner wall of the cover.

Therefore, the valve returning mechanism can be set into the motor housing at the same time that the housing opening is closed by the cover.

In another aspect of the present teachings, the housing opening is defined in the motor housing in order to insert the first spring support member and the coil spring into the motor housing.

In another aspect of the present teachings, the motor housing comprises a tubular portion that includes the housing opening. The cover is closely fitted into the tubular portion.

In another aspect of the present teachings, the rotor shaft has an end portion comprising a non-circular cross section. The first spring support member has a corresponding fitting hole having a non-circular configuration conforming to the cross sectional configuration of the end portion of the rotor shaft. The end portion of the rotor shaft is press-fitted into the fitting hole of the first spring support member. A plurality of fitting projections is formed on the inner periphery of the fitting hole and extends in a fitting direction of the end portion of the rotor shaft. The fitting hole includes at least one corner portion. A substantially semi-circular recess is formed in the first spring support member around the corner portion to extend parallel to the fitting projections.

Because the end portion of the rotor shaft and the fitting hole of the first spring support member have a non-circular cross section and are fitted with each other, the first spring support member can be reliably connected to the rotor shaft so as to not rotate relative to each other. In addition, because the fitting projections are formed on the inner periphery of the fitting hole, the fitting force may be concentrated at the fitting projections during the fitting operation. Consequently, the fitting projections may be crushed or otherwise deformed to accommodate a tight fit of the end portion of the rotor shaft. Further, since the fitting projections are deformed, the first spring support member is reliably prevented from being broken during the fitting operation. Since the semi-circular recess is formed around the corner portions of the fitting hole, no acute angle portions or stress concentration sites are formed at the corner portions along the inner periphery of the fitting hole. Therefore, the first spring member may be stronger and result in less breakage at the corner portions.

In another aspect of the present teachings, the fitting hole has a substantially semi-circular configuration with a curved portion and a linear portion. The fitting projections are formed along the curved portion. A semi-circular recess is formed around each end of the linear portion.

In another aspect of the present teachings, the first spring support member includes a first stopper portion. The second spring support member includes a second stopper portion. The first stopper portion and the second stopper portion contact with each other so as to prevent or limit further movement of the valve member in one direction. The movement of the valve member is limited in the direction of movement resulting from the biasing force of the coil spring. The biasing force of the coil spring causes the valve member to return to the first position. The valve member can then be reliably returned to the first position or the original position and not beyond this point when the motor has been de-energized or the supply of current to the motor has been interrupted.

In another aspect of the present teachings, the valve devices further include a retainer and a positioning protrusion formed on the inner wall of the cover. The retainer serves to retain engagement of the second end of the coil spring with the second spring support member. The positioning protrusion serves to support the coil spring in a position axially aligned with the rotor shaft. Therefore, the fitting operation of the coil spring on to the first spring support member, which is coupled to the rotor shaft, can be easily performed.

In another aspect of the present teachings, the cover has a substantially cylindrical tubular configuration with an open end and a closed end. A positioning projection and a positioning recess for engaging the positioning projection are formed on one and the other of the cover and the tubular portion of the motor housing in order to position the cover relative to the tubular portion in a circumferential direction. Therefore, the cover can be reliably positioned relative to the motor housing in a predetermined position in the circumferential direction.

In another aspect of the present teachings, valve devices are taught that include a valve body, a valve member, and a motor. The valve body has a frame mounted within a communication opening defined in a partition wall disposed within a surge tank. The valve body includes a frame defining a frame opening. The valve member is rotatably mounted to the valve body in order to open and close the frame opening. The motor is coupled to the valve member via a rotor shaft of the motor in order to rotate the valve member. The valve member rotates from a first position to a second position when a current is supplied to the motor. The current is supplied to the motor in order to produce a rotational torque for rotating the rotor shaft in a first direction. For example, the first position may be a fully opened position and the second position may be a fully closed position. The valve devices further include a spring, such as a coil spring. The coil spring serves to return the valve member from the second position to the first position when the supply of current to the motor is stopped or interrupted. The rotational torque of the motor varies in response to a rotational angle of the rotor shaft when a substantially constant current is supplied to the motor. The rotational torque produced by the motor is greater than the rotational torque of the spring during the rotation of the rotor shaft from a first rotational angle (.theta.x), corresponding to the first position of the valve member, to a second rotational angle (.theta.y), corresponding to the second position of the valve member.

Also in this arrangement, the rotor shaft may be directly coupled to the valve member. Therefore, no link mechanism or speed reduction mechanism is interposed between the motor and the valve member. As a result, the construction of the valve device can be simplified and may be relatively compact in size. In addition, due to the above selection of the rotational torque of the motor, the motor can reliably rotate the valve member from the first position to the second position against the rotational torque, i.e., the biasing force, of the spring.

In another aspect of the present teachings, the rotational torque produced by the motor changes from a first torque (TM1) to a maximum torque and further to a second torque (TM2) during the rotation of the rotor shaft from the first rotational angle (.theta.x) to the second rotational angle (.theta.y). The second torque (TM2) is greater than the first torque (TM1). In addition, the difference between the second torque (TM2) and the first torque (TM1) is greater than the increased value of the rotational torque applied by the spring during rotation from the first position to the second position.

Therefore, by setting the first torque (TM1) of the motor produced at the first rotational angle (.theta.x) (corresponding to the first position of the valve member) to be greater by a necessary minimum value than the rotational torque of the spring produced at the same rotational angle (.theta.x), it can be ensured that the rotational torque of the motor exceeds the rotational torque of the spring throughout the rotational range between the first position and the second position.

In another aspect of the present teachings, the ratio of increase of the rotational torque during a rotational range around the first rotational angle (.theta.x) is greater than the ratio of decrease of the rotational torque during a rotational range around the second rotational angle (.theta.y). Therefore, with the second torque (TM2) at the second rotational angle (.theta.y) set to be greater than the first torque (TM1) at the first rotational angle (.theta.x), the difference between the second torque (TM2) and the first torque (TM1) can be set to have a large value.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an intake air control device according to a first representative embodiment; and

FIG. 2 is a front view of the valve device; and

FIG. 3 is a plane view of the valve device; and

FIG. 4 is a cross sectional view taken along line IV--IV in FIG. 3; and

FIG. 5 is a cross sectional view taken along line V--V in FIG. 3; and

FIG. 6 is an exploded perspective view of the valve device; and

FIG. 7 is a plan view of a valve body; and

FIG. 8 is a rear view of the valve body; and

FIG. 9 is a cross sectional view taken along line IX--IX in FIG. 7; and

FIG. 10 is a cross sectional view taken along line X--X in FIG. 7; and

FIG. 11 is a cross sectional view taken along line XI--XI in FIG. 7; and

FIG. 12 is a cross sectional view taken along line XII--XII in FIG. 9; and

FIG. 13 is a left side view of the valve device and showing a mount region of the valve device on a surge tank; and

FIG. 14 is a plan view of the valve device and showing a mount region of the valve device on a surge tank; and

FIG. 15 is a cross sectional view taken along line XV--XV in FIG. 13; and

FIG. 16 is a cross sectional view taken along line XVI--XVI in FIG. 15; and

FIG. 17 is a cross sectional view taken along line XVII--XVII in FIG. 15; and

FIG. 18(a) is a perspective view of the surge tank; and

FIG. 18(b) is a schematic view showing an intake system of an engine; and

FIG. 19 is a graph showing the relation between the rotational speed of the engine and a torque; and

FIG. 20 is an enlarged view of the valve device incorporating a representative valve returning device; and

FIGS. 21(A) and 21(B) are a plan view and a partial cross sectional side view of a first support member of the representative valve returning device; and

FIG. 21(C) is a view similar to FIG. 21(B) but showing the state where the first support member is fixed to the rotor shaft; and

FIG. 21(D) is an enlarged view of a pressure-fitting hole formed in the first support member; and

FIG. 22(A) is a vertical sectional view of a cover of the representative valve returning device; and

FIGS. 22(B) and 22(C) are cross sectional views taken along line B--B and line C--C in FIG. 22(A);

FIG. 23(A) is a plan view showing the first support member and a torque spring fitted to the first support member; and

FIGS. 23(B) and 23(C) are cross sectional views showing the assembled state of the valve returning device taken along line XXIII--XXIII in FIG. 20; and

FIGS. 24(A) and 24(B) are a rear view and a vertical sectional view of a representative motor for rotating a valve member; and

FIGS. 25(A), 25(B), 25(C) and 25(D) are rear views of the representative motor and showing the operation of the motor; and

FIG. 26(A) is a rear view of a stator core of the motor; and

FIG. 26(B) is a cross sectional view taken along line-XXVI--XXVI in FIG. 26(A); and

FIG. 26(C) is a view of the stator core as viewed in a direction indicated by an arrow XXVI(C) in FIG. 26(A); and

FIG. 26(D) is a rear view of the motor and showing the magnetic flux produced by the motor; and

FIG. 27(A) is a graph showing characteristics of the rotational torque produced by the motor; and

FIG. 27(B) is a graph showing the relation between characteristics of the rotational torque produced by the motor and the characteristics of the rotational torque produced by the torque spring; and

FIG. 28 is a schematic view of an electric circuit of the motor.

DETAILED DESCRIPTION OF THE INVENTION

Each of the additional features and teachings disclosed above and below may be utilized separately or in conjunction with other features and teachings to provide improved valve devices. Representative examples of the present invention, which examples utilize many of these additional features and teachings both separately and in conjunction with one another, will now be described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Moreover, various features of the representative examples and the dependent claims may be combined in ways that are not specifically enumerated in order to provide additional useful embodiments of the present teachings.

A representative embodiment will now be described with reference to FIGS. 1 to 19. The representative embodiment relates to a valve device for controlling flow of intake air for use with an acoustic control induction system (ACIS).

The ACIS will be first described with reference to FIGS. 18 (A) and 18(B). A surge tank 100 constitutes an intake air system for six-cylinder internal combustion engine (not shown). A first tank chamber 111 and a second tank chamber 112 are defined within the surge tank 100 and are separated from each other by a partition wall 104. Intake branch tubes 114, 115, and 116, are connected between the first tank chamber 111 and engine cylinders (not shown) having different intake strokes from one another. Similarly, intake branch tubes 117, 118, and 119, are connected between the second tank chamber 112 and engine cylinders (not shown) having different intake strokes from one another. A valve device 1 is mounted on the partition wall 104 and has a valve member 70 that is operable to permit and interrupt communication between the first tank chamber 111 and the second tank chamber 112. The surge tank 100 has a duct portion 109 that is connected to an air cleaner 122 via a throttle body 121. A throttle valve 113 is disposed within the throttle body 121 and is opened and closed in response to the operation of an accelerator pedal (not shown).

During a high-load and low-speed operation of the engine, the valve member 70 of the valve device 1 is closed. For this situation, the intake-air branching section 109a within the duct portion 109 of the surge tank 100 serves as a node of air-column oscillation that may be produced due to pulsations of the intake air. Therefore, the frequency of the oscillation may be lowered. As a result, due to the inertial force of the intake air, the efficiency of filling the intake air increases, so that the torque referred to as "shaft torque" may increase during the low-speed operation, as indicated by the torque line A in FIG. 19. However, during a high-load and high-speed operation of the engine, the valve member 70 of the valve device 1 is opened. For this situation, the open ends of the branch tubes 114 to 119 serve as nodes of air-column oscillation that may be produced due to pulsations of the intake air. Therefore, the frequency of the oscillation may be higher. As a result, also due to the inertial force of the intake air, the efficiency of filling the intake air increases, so that the torque may increase during the high-speed operation as indicated by torque line B in FIG. 19.

The detailed construction of the surge tank 100 will now be described with reference to FIGS. 14 to 17. For the purposes of explanation, front and rear directions, left and right directions, and upper and lower directions used in this specification with regard to the surge tank 100 and the valve device 1 will be determined as indicated by reference arrows in the drawings. As shown in FIG. 15, a valve insertion hole 102 is formed in a rear wall 101 of the surge tank 100. The valve insertion hole 102 is in a position rearwardly opposing to the partition 104. The valve insertion hole 102 has a substantially rectangular configuration, elongated in the right and left directions. A generally U-shaped cutout recess 105 is formed in the partition wall 104 in a position opposing the valve insertion hole 102.

A projection 106 is formed on the front edge of the cutout recess 105 (to the right in FIG. 15), so that the projection 106 protrudes in the rearward direction from the front edge. The projection 106 has a width 106w in right and left directions along the front edge of the cutout recess 105. The right and left ends of the projection 106 are respectively inclined toward the right and left edges of the cutout recess 105. The protruding distances of the projection 106 decrease towards the right and left ends of the projection 106

As shown in FIG. 16, the projection 106 has a thickness 106t that is larger than the thickness of the partition wall 104. In addition, the thickness 106t of the projection 106 decreases in the protruding direction (rearward direction). Upper and lower flanges 107 extend outward (away from a horizontal centerline of the projection 106) and rearward from the base portion of the projection 106, and are configured to be symmetrical to each other. The width in the right and left directions of the upper and lower flanges 107 is substantially the same as the width 106w (see FIG. 15) of the projection 106.

As shown in FIG. 15, a right and left pair of upper and lower guide portions 108 extend from the right and left walls of the cutout recess 105. The guide portions 108 are positioned on the middle portions of the front side of the right and left walls. The right and left guide portions 108 are symmetrical to each other. The upper and lower guide portions 108 are symmetrical to each other. As shown in FIG. 17, each of the guide portions 108 defines a channel 108a that is adapted to receive a corresponding frame portion 17(20) of a valve member 70. As shown in FIG. 15 and FIG. 17, a portion of the wall between the upper and lower guide portions 108, on the right and left walls of the cutout recess 105, is formed so as to be continuous with the wall surface of the cutout recess 105 to the front and rear of the guide portions 108.

The valve device 1 will now be described. As shown in FIG. 1, the valve device 1 includes a valve body 10 and a valve member 70 rotatably supported on the valve body 10. An electric motor 30, configured as a DC torque motor, is integrated with the valve body 10. The motor 30 rotates the valve member 70 for opening and closing operations of the valve device 1. First, the valve body 10 will be described. The valve body 10 may be made of resin and has a vertical base plate 11, a frame 12, and a motor housing 31 that are formed integrally with one another. The frame 12 extends horizontally from the front surface of the base plate 11. The motor housing 31 is positioned on the rear side of the base plate 11. Thus, the base plate 11 is positioned between the frame 12 and the motor housing 31. A portion of the base plate 11 extends outward beyond the motor housing 31 and serves as a mounting flange for mounting the valve body 10 to the surge tank 100 (see FIGS. 13 to 15).

As shown in FIGS. 6 and 7, the frame 12 has a substantially rectangular configuration elongated in the forward and rearward directions and is fitted into the valve insertion hole 102 and the cutout recess 105 (see FIG. 15). The frame 12 has a rear frame portion 13 (on the side of the motor 30) connected to the base plate 11, a left frame portion 17 and a right frame portion 20 respectively extending forward from the left and right ends of the rear frame portion 13, and a front frame portion 23 (on the side opposite to the motor 30) connected to the front ends of the left and right frame portions, 17 and 20. The distance between the left and right frame portions gradually decreases in the forward direction. As a result, the frame 12 has a tapered configuration in the forward direction.

The rear frame portion 13 of the frame 12 is configured as a substantially linear strip extending in the right and left directions. A cylindrical support portion 14 is formed in the middle portion between the right and left ends of the rear frame portion 13. The support portion 14 has a central axis L along the forward and rearward directions. As shown in FIG. 9, a support hole 14a is formed in the support portion 14 and extends through the support portion 14 in an axial direction. In other words, the support hole 14a extends through the rear frame portion 13. The support hole 14a further extends through the base plate 11 and opens into a tubular portion 32 of the motor housing 31. A bearing bush 15 is press-fitted into the support hole 14a from the rear side of the support hole 14a. In addition as shown in FIG. 8, the support portion 14 is heated and crimped at suitable circumferential points 11a (four points 11a are shown in this representative embodiment) in position axially adjacent to the open end of the support hole 14a on the side of the base plate 11. Consequently, the bearing bush 15 is staked or is prevented from being removed from the support hole 14a. In order to accommodate the staking procedure, a space 14b is defined within the support hole 14a between the rear facing open end of the support hole 14a and the fitted position of the bearing bush 15 (see FIG. 9).

As shown in FIG. 10, the rear frame portion 13 has a thickness 13t that is slightly smaller than a diameter 14d of the support portion 14. Although the thickness 13t is smaller than the diameter 14d in this representative embodiment, the thickness 13t may be equal to or greater than the diameter 14d. More importantly, the cross sectional configuration of the rear frame portion 13 is designed to fit within the valve insertion hole 102 of the surge tank 100 (see FIG. 15). In particular, the rear frame portion 13 is molded such that the thickness 13t is greater than a diameter of a rotor shaft 51 (see FIG. 6) that will be explained later.

Four thickness reduced portions 16, configured as recesses, are formed in the rear frame portion 13 and arranged symmetrically to each other with regard to the right and left directions and the upper and lower directions. The thickness reduced portions 16 extend along the length (right and left directions) of the rear frame portion 13 except for the support portion 14, right and left ends, and forward and rearward ends of the frame portion 13. In this way, the thickness of the rear frame portion 13 is reduced at regions where the upper and lower thickness reduced portions 16 are opposed to each other.

As shown in FIGS. 6 and 7, the front frame portion 23 extends in the right and left directions. A substantially cylindrical support portion 24 is formed at the central position of the front frame portion 23 (with regard to the right and left directions) and has a central axis coincident to axis L of the cylindrical support portion 14 of the rear frame portion 13. As shown in FIG. 9, a support hole 24a is formed in the support portion 24 and extends through the support portion 24 in the axial direction. A bearing bush 25 is press fitted into the support hole 24a from the rear side of the support hole 24a. As shown in FIG. 4, one end (the front end as viewed in FIG. 4) of a support shaft 22 is inserted into the bearing bush 25, so that the bearing bush 25 rotatably supports the support shaft 22. The other end (the rear end) of the support shaft 22 is press-fitted into an axial hole 72a formed in the front portion of the valve member 70.

Referring to FIG. 6, the left frame portion 17, the right frame portion 20, and the front frame portion 23 may have a thickness that is substantially the same as the thickness 13t (see FIG. 10) of the rear frame portion 13. However, because the front frame portion 23 has an engaging recess 28 formed in the outer periphery, the front frame portion 23 may have a thickness greater than the thickness 13t. The engaging recess 28 will be explained later.

As shown in FIG. 7, a left valve seat 26L and a right valve seat 26R are formed in a stepped manner on the inner periphery of the frame 12, with an exception for the areas around the support portions 14 and 24. The front and rear ends of each of the left and right valve seats 26L and 26R are curved toward the central axis L. More specifically, the left and right valve seats 26L and 26R are symmetrical about a point that corresponds to the central axis L as viewed from the forward and rearward directions (see FIG. 11). Thus, the left valve seat 26L is oriented downward and the right valve seat 26R is oriented upward.

As shown in FIG. 6, a substantially U-shaped engaging recess 27 is formed in the outer periphery of the frame 12, along the outer peripheries of the frame portions 13, 17, 20, and 23, (see FIGS. 10 and 11) and is open to the outside. Thus, the engaging recess 28 formed in the front frame portion 23 is defined as a part of the engaging recess 27. The width of the engaging recess 28 is greater than the width of the remaining parts of the engaging recess 27 formed in the left and right frame portions 17 and 20 (see FIG. 6). The engaging recess 28 extends across the support portion 24 and communicates with the support hole 24a formed in the support portion 24 (see FIG. 9). The engaging recess 28 is adapted to receive the projection 106 of the surge tank 100 with the intervention of a gasket 29 (see FIG. 16) as will be hereinafter explained.

The gasket 29 is made of a resilient material, such as a rubber, and extends linearly continuously along the engaging recess 27, including the engaging recess 28, and has an inner portion fitted into the engaging recess 27 (see FIGS. 1 to 5). The outer portion of the gasket 29 extends outwardly from the outer periphery of the frame 12 as shown in FIG. 5 and resiliently contacts with the peripheral edge of the cut-out recess 105 formed in the partition wall 104, and with the right and left edges of the valve insertion hole 102 of the surge tank 100 (see FIG. 15). The gasket 29 provides a seal between the frame 12 and the partition 104 (see FIG. 17).

As shown in FIG. 6, a portion of the gasket 29, corresponding to the front frame portion 23 of the frame 12, is configured to define an engaging recess 29a that is open on the front side. In addition, engaging walls 29b are formed on the upper and lower side of the engaging recess 29a. The engaging recess 29a resiliently engagingly receives the projection 106 of the surge tank 100. At the same time, the engaging walls 29b resiliently contact with the corresponding upper and lower flanges 107 of the partition wall 104 (see FIG. 16).

As shown in FIGS. 6 and 7, the motor housing 31 is formed integrally with the rear surface of the base plate 11. As shown in FIG. 12, a stator 40 is integrated within the motor housing 31 via an insertion molding process. The stator 40 has a stator core 41 made of magnetic material. The stator core 41 includes a pair of teeth 42 and a pair of arms 43. The arms 43 magnetically connect the respective teeth 42 to the coil assembly 44. The coil assembly 44 includes an iron core 45 and a stator coil 47. The stator coil 47 is wound around the core 45 with the intervention of a bobbin 46. As shown in FIG. 8, terminals 48, electrically connected to the stator coil 47, are integrated within a connector 34 by an insertion molding process. The connector 34 is molded integrally with the motor housing 31. As shown in FIG. 9, a substantially cylindrical tubular portion 32 is formed on the rear side of the motor housing 31. The tubular portion 32 has a central axis coincident with the central axis L.

Referring to FIG. 4, a rotor 50 in combination with the stator 40 constitutes the motor 30. The rotor 50 has a rotor shaft 51, a rotor core 53 press-fitted onto the rear end of the rotor shaft 51 and fixed in position relative to the rotor shaft 51, and a pair of magnets 54 and 55 attached to the outer periphery of the rotor core 53 (see FIG. 6). The rotor core 53 is made of magnetic material and has a substantially cylindrical configuration. Each of the magnets 54 and 55 has an arc-shaped configuration and is magnetized in the radial direction. In addition, the magnets 54 and 55 are secured to the rotor core 53 with their magnetized directions being opposite to each other, so that N and S poles are formed on the rotor 50. As shown in FIG. 4, a spring guide 57 is engagingly fitted on the rear end of the rotor shaft 51. The spring guide 57 is prevented from being removed from the rotor shaft 51 and from rotating relative to the rotor shaft 51.

As shown in FIG. 4, the front end of the rotor shaft 51 is inserted into the support hole 14a formed in the support portion 14 of the rear frame portion 13 of the valve body 10. The rotor shaft 51 is inserted via the tubular portion 32 of the motor housing 31 (see FIG. 9) and a space 42a formed between the teeth 42 of the stator core 41 (see FIG. 12). As a result, the bearing bush 15 fitted into the support hole 14a rotatably supports the rotor shaft 51. The rear end of the rotor shaft 51 is press-fitted into an axial hole 73a formed in the valve member 70, so that the rotor 51 is joined to the valve member 70. In addition, the magnets 54 and 55 of the rotor 50 are rotatably disposed within the space 42a between the teeth 42 (see FIG. 12).

As shown in FIG. 4, a cover 60 is fitted into the tubular portion 32 of the motor housing 31 via an open end 32a of the tubular portion 32 in order to close the open end 32a. The cover 60 contacts with the inner wall of the tubular portion 32 along a predetermined length. As a result, the cover 60 is prevented from rotating relative to the tubular portion 32. In addition, a part of the tubular portion 32 around the open end 32a is heated and crimped along the entire circumferential length so as to be bent inwardly. Consequently the cover 60 is reliably prevented from being removed from the tubular portion 32. Further, an O-ring 62 is interposed between the outer peripheral surface of the cover 60 and the inner wall of the tubular portion 32 in order to provide a resilient seal therebetween.

A torque spring 64 is interposed between the cover 60 and the spring guide 57 in order to normally bias the rotor 50 in the open direction. Although not shown in FIGS. 1 to 19, stoppers are respectively mounted on the cover 60 and the spring guide 57. The stoppers may engage each other when the valve member 70 has rotated to a predetermined fully opened position. The valve member 70 is subsequently prevented from rotating beyond the predetermined fully opened position due to the engagement of the stoppers. The torque spring 64 and the stoppers constitute a valve returning mechanism 63.

A current may be supplied to the terminals 48 (see FIG. 8) under the control of an ECU (electronic control unit) (not shown), exciting the stator coil 47 of the stator 40 (see FIG. 12). This causes the poles of the rotor 50, produced by the magnets 54 and 55, to be attracted to the corresponding opposing poles of the stator core 41, produced by the excited stator coil 47. As a result, torque is produced to rotate the rotor 50 in a closing direction (a direction indicated by an arrow S in FIG. 5) of the valve member 70 against the biasing force of the torque spring 64. When the supply of the current to the stator coil 47 is interrupted, no torque is produced to rotate the rotor 50 in the closing direction. As a result, the rotor 50 is rotated in the opening direction of the valve member 70 because of the biasing force of the torque spring 64. The state where the current is supplied to the stator coil 47 will hereinafter be called the "ON state" of the motor 30. The state where no current is supplied to the stator coil 47 will hereinafter be called the "OFF state" of the motor 30.

As shown in FIGS. 7 and 8, a plate-like rib 35 is formed on the motor housing 31 and extends along and between the outer surface of the tubular portion 32 and the rear surface of the base plate 11. The rib 35 reinforces the tubular portion 32. A thickness 35t of the rib 35 (see FIG. 8) is set so as to provide a laser transmission factor equal to that of the base plate 11. Therefore, in case that the base plate 11 is laser-welded to the rear wall 101 of the surge tank 100, the laser transmission factor of the base plate 11 can be easily and non-destructively determined by measuring the transmission factor of the rib 35.

The valve member 70 will now be described. Referring to FIG. 6, the valve member 70 may be made of aluminum and may be molded through a die-casting operation. The valve member 70 has a plate-like configuration in order to open and close an opening 12a formed within the frame 12 of the valve body 10. A front cylindrical support portion 72 and rear cylindrical support portion 73 are formed on the front and rear ends of the valve member 70. In an assembled state, the front and rear support portions 72 and 73 have respective axial holes 72a and 73a (see FIG. 4) extending along the central axis L. The support portions 72 and 73 are configured to be symmetrical to each other (see FIG. 4).

As shown in FIG. 4, the rear end of the support shaft 22 is press-fitted into the axial hole 72a of the front support portion 72. On the other hand, the front end of the rotor shaft 51 of the rotor 50 is press fitted into the axial hole 73a of the rear support portion 73. Consequently, the frame 12 of the valve body 10 rotatably supports the valve member 70 in order to open and close the opening 12a of the frame 12 (see FIGS. 1 to 5). The support shaft 22 and the rotor shaft 51 may have approximately the same diameter. The support shaft 22 and the rotor shaft 51 may be made of iron coated with defric coatings in order to improve the wear resistance. In this way, the support shaft 22 is coupled to one end of the valve member 70 on the side opposite to the motor 30 and the rotor shaft 51 is coupled to the other end of the valve member 70 on the side of the motor 30.

As described previously, in the ON state of the motor 30, the valve member 70 rotates in the closing direction (the direction indicated by the arrow S in FIG. 5) together with the rotor 50 (see FIG. 4). The excitation of the stator 40 produces the rotational torque causing the rotation in the closing direction, so that the valve member 70 closes the opening 12a of the frame 12 of the valve body 10. Conversely, when the motor 30 is turned to the OFF state, the valve member 70 rotates in the opening direction (the direction indicated by an arrow O in FIG. 5) together with the rotor 50. The resilient restoring force of the torsion spring 64 causes the rotation in the opening direction, so that valve member 70 opens the opening 12a of the frame 12 of the valve body 10.

In this representative embodiment, the rotational range of the valve member 70 is limited within an angle .theta.1 between the fully closed position (indicated by chain lines in FIG. 5) and the fully opened position (indicated by solid lines in FIG. 5). For example, the angle .theta.1 may be set to an angle of 40.degree.. In addition, the fully closed position may be set such that the valve member 70 is inclined by an angle .theta.2 relative to a horizontal reference plane 12b that extends along the central axis L of the frame 12. For example, the angle .theta.2 may be set to an angle of 10.degree..

As shown in FIG. 5, the valve member 70 has a large thickness portion 74 extending across the central axis L. Right and left small thickness portions 75 are on both sides of the large thickness portion 74. Each of the large thickness portion 74 and the right and left small thickness portions 75 are configured to be symmetrical with regard to the longitudinal axis of the valve member 70. The right and left small thickness portions 75 have a thickness approximately equal to one-quarter of the thickness of the large thickness portion 74. However, the thickness in the regions of the support portions 72 and 73 (see FIG. 6) may be greater than one-quarter of the thickness of the large thickness portion 74. In addition, the outer surfaces on both sides of the large thickness portion 74 join the corresponding outer surfaces of the right and left small thickness portions 75 via convex curved surfaces 76. Further, the front side curved surfaces 76 converge at a substantially middle position of the front side support portion 72. The rear side curved surfaces 76 converge at a substantially middle position of the rear side support portion 73 (see FIG. 6).

As shown in FIG. 4, air releasing holes 77 are formed in the valve member 70 (on the lower side as viewed in FIG. 4) in communication with axial holes 72a and 73a. The air releasing holes 77 allow the air to be rapidly and smoothly discharged from the axial holes 72a and 73a when the support shaft 22 and the rotor shaft 51 are respectively fitted into the axial holes 72a and 73a. In addition, reference holes 78 are formed in the valve member 70 and are positioned in the vicinity of the respective air releasing holes 77. The reference holes 78 may provide references during the machining operation of the valve member 70. Because the air releasing holes 77 and the reference holes 78 are formed on the lower side of the valve member 70, a side that is typically oriented downward during normal operation, any condensed water or moisture as wel