Pulley type torque transmitting apparatus Number:6,802,779 from the United States Patent and Trademark Office (PTO) owispatent

Title: Pulley type torque transmitting apparatus

Abstract: A hole is formed in a damper rubber, where by when a compressive load is small, pillar portions undergo a flexural deformation so as to result in buckling deformation. On the other hand, when the compressive load becomes large, the hole collapses and the damper rubber undergoes a compressive deformation so as to collapse itself. Thus, since the damper rubber has a non-linear characteristic such that an elastic modulus thereof at an amount of deformation exceeding a predetermined amount is larger than that at an amount of deformation less than the predetermined amount, the transmission of a large torque can be implemented while absorbing a torque fluctuation sufficiently.

Patent Number: 6,802,779 Issued on 10/12/2004 to Tabuchi,   et al.

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Inventors:	Tabuchi; Yasuo (Toyoake, JP); Ohguchi; Junichi (Toyoake, JP); Ito; Makoto (Okazaki, JP); Saiki; Manabu (Chiryu, JP); Kurohata; Kiyoshi (Kariya, JP)
Assignee:	Denso Corporation (Kariya, JP)
Appl. No.:	09/977,356
Filed:	October 16, 2001

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Foreign Application Priority Data

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Oct 27, 2000 [JP]			2000-328974
Oct 31, 2000 [JP]			2000-333285
Nov 09, 2000 [JP]			2000-342121
Nov 09, 2000 [JP]			2000-342122
Nov 10, 2000 [JP]			2000-343665
Nov 10, 2000 [JP]			2000-343668
Apr 18, 2001 [JP]			2001-120161

Current U.S. Class:	464/32 ; 464/76; 474/94
Field of Search:	464/73,74,32,76,85,83,89 267/153 474/94,902,903 417/223,269

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References Cited [Referenced By]

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U.S. Patent Documents

	1504279		August 1924		Spicer
	2446942		August 1948		McFarland
	2924082		February 1960		Reich
	3106076		October 1963		Bastow
	3345831		October 1967		Boole
	3505832		April 1970		Braithwaite
	4328879		May 1982		Tone
	4795402		January 1989		Reichardt
	4828090		May 1989		Matsushita
	5899811		May 1999		Kishibuchi et al.
	6045448		April 2000		Kern et al.
	6056514		May 2000		Fukai
	6065943		May 2000		Suito et al.
	6612813		September 2003		Kimura et al.

Foreign Patent Documents

	1 575 752		Jan., 1970		DE
	30 38 506		Apr., 1982		DE
	557705		Dec., 1943		GB
	543705		Jun., 1958		IT
	47-45989		Nov., 1972		JP

Primary Examiner: Binda; Greg
Attorney, Agent or Firm: Posz & Bethards, PLC

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Parent Case Text

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CROSS REFERENCE TO RELATED APPLICATION

This application is based on and incorporates herein by reference Japanese Patent Application Nos. 2000-328974 filed on Oct. 27, 2000, 2000-333285 filed on Oct. 31, 2000, 2000-342121 filed on Nov. 9, 2000, 2000-342122 filed on Nov. 9, 2000, 2000-343665 filed on Nov. 10, 2000, 2000-343668 filed on Nov. 10, 2000, and 2001-120161 filed on Apr. 18, 2001.

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Claims

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What is claimed is:

1. A torque transmitting apparatus for transmitting a torque from a driving source to a rotary device, comprising: a first rotor driven in a rotating direction upon receipt of the torque from said driving source via a member disposed between said first rotor and said driving source, wherein: said first rotor receives a radial load in a radial direction thereof from said member while being driven in the rotating direction; said first rotor includes an outer annular portion, an inner annular portion and a plurality of projections; the inner annular portion is radially and inwardly spaced from the outer annular portion; and each projection extends radially and inwardly from the outer annular portion to the inner annular portion and axially extends in a direction generally parallel to a rotational axis of said first rotor; a radial bearing disposed between the first rotor and a support member, wherein said radial bearing supports the first rotor rotatably on said support member against the radial load on said first rotor; a second rotor connected to a rotating portion of said rotary device and rotating together with said rotating portion, wherein said second rotor includes a plurality of projections, each of which extends in a direction generally parallel to said rotational axis of said first rotor and is placed between two corresponding projections of said plurality of projections of said first rotor; and a plurality of pairs of torque transmitting members disposed between said first rotor and said second rotor for transmitting the torque in the rotating direction to said second rotor, wherein: each torque transmitting member is deformable elastically in the rotating direction and is placed between a corresponding one of said plurality of projections of said first rotor and a corresponding one of said plurality of projections of said second rotor; each torque transmitting member has a non-linear spring characteristic; each pair of torque transmitting members is arranged such that said torque transmitting members of each pair are arranged, in the rotating direction, on opposite sides, respectively of a corresponding one of said projections; and each pair of torque transmitting members is constructed such that said torque transmitting members of said pair are joined together by a connecting member, which is axially positioned between said second rotor and said corresponding one of said projections on one axial side of said corresponding one of said projections.

2. A torque transmitting apparatus according to claim 1, wherein said torque transmitting member is made of rubber or elastomer having a hole.

3. A torque transmitting apparatus according to claim 1, wherein each torque transmitting member is made of rubber or elastomer, and the transmitting member is deformed by flexural deformation in response to torque in the rotating direction that is smaller than a predetermined torque and is deformed by compressive deformation in response to torque in the rotating direction that is larger than the predetermined torque, the deformation amount of the flexural deformation being larger than the deformation amount of the compressive deformation.

4. A torque transmitting apparatus according to claim 1, wherein each torque transmitting member is made of rubber or elastomer, and the transmitting member has a first portion that is deformed by a flexural deformation in response to torque in the rotating direction that is smaller than a predetermined torque and a second portion that is deformed by compressive deformation in response to torque in the rotating direction that is larger than the predetermined torque, the deformation amount of said first portion being larger than the deformation amount of said second portion.

5. A torque transmitting apparatus according to claim 1, wherein each torque transmitting member is made of rubber or elastomer, and the transmitting member has a first portion and a second portion, the first portion being deformed in a first amount by flexural deformation in response to torque in the rotating direction, the second portion being deformed in a second amount by compressive deformation in response to torque in the rotating direction, the first amount being increased more than the second amount as the torque in the rotating direction is increased, wherein the first amount is always larger than the second amount.

6. A torque transmitting apparatus according to claim 1, wherein each torque transmitting member is free from the radial load.

7. A torque transmitting apparatus according to claim 1, wherein said member disposed between said first rotor and, said driving source is a V belt.

8. A torque transmitting apparatus according to claim 1, wherein said support member is a housing of said rotary device.

9. A torque transmitting apparatus according to claim 8, wherein said rotary device is a compressor.

10. A torque transmitting apparatus according to claim 1, wherein each pair of torque transmitting members is constructed such that said torque transmitting members of said pair are tapered in opposite directions, respectively.

11. A torque transmitting apparatus according to claim 1, wherein: said second rotor further includes a torque limiter mechanism, which disables transmission of said torque from said first rotor to said rotary device when said torque transmitted from said first rotor to said torque limiter mechanism reaches a predetermined torque; and said torque limiter mechanism is arranged in such a manner that an axial extent of said torque limiter mechanism is within an axial extent of said first rotor.

12. A torque transmitting apparatus for transmitting a torque from a driving source to a rotary device, comprising: a first rotor driven in a rotating direction upon receipt of the torque from said driving source via a member disposed between said first rotor and said driving source, wherein: said first rotor receives a radial load in a radial direction thereof from said member while being driven in the rotating direction; said first rotor includes an outer annular portion, an inner annular portion and a plurality of projections; said inner annular portion is radially and inwardly spaced from said outer annular portion; and each protection radially and inwardly extends from said outer annular portion to said inner annular portion, and each projection axially extends in a direction generally parallel to a rotational axis of said first rotor; a radial bearing disposed between the first rotor and a support member, wherein said radial bearing supports the first rotor rotatably on said support member against the radial load on said first rotor; a second rotor connected to a rotating portion of said rotary device and rotating together with said rotating portion, wherein said second rotor includes a plurality of projections, each of which extends in a direction generally parallel to said rotational axis of said first rotor and is placed between two corresponding projections of said plurality of projections of said first rotor; and a plurality of pairs of torque transmitting members disposed between said first rotor and said second rotor for transmitting the torque in the rotating direction to said second rotor, wherein: each torque transmitting member is deformable elastically in the rotating direction and is placed between a corresponding one of said plurality of projections of said first rotor and a corresponding one of said plurality of projections of said second rotor; each torque transmitting member is deformed by a flexural deformation when an amount of deformation is less than a predetermined amount, and is deformed by a compressive deformation when the amount of deformation is more than the predetermined amount, whereby an elastic modulus of said torque transmitting member at the amount of deformation over the predetermined amount becomes larger than that at the amount of deformation below the predetermined amount; each pair of torque transmitting members is arranged such that said torque transmitting members of said pair are arranged, in the rotating direction, on opposite sides, respectively, of a corresponding one of said plurality of projections; and each pair of torque transmitting members is constructed such that said torque transmitting members of said pair are joined together by a connecting member, which is axially positioned between said second rotor and said corresponding one of said plurality of projections on one axial side of said corresponding one of said plurality of projections.

13. A torque transmitting apparatus according to claim 12, wherein said torque transmitting member is made of rubber or elastomer having a hole.

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Description

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a torque transmitting apparatus for transmitting torque from a driving source such as an engine to a rotary device such as an alternator or a compressor disposed within an engine room of a vehicle.

2. Description of Related Art

A rotary device such as a compressor which operates with power provided from an engine undergoes a change in torque fed thereto upon a change in load on the engine. When the torque fed to the rotary device changes, moving components oscillate, with consequent likelihood of noise generation.

The problem may be solved by adopting means such that a torque transfer member formed of an elastic material, that is, rubber, is disposed in a power transfer path extending from a drive source such as an engine up to a rotary device such as a compressor.

In this case, for absorbing a torque variation sufficiently it is desirable that the elastic modulus of the torque transfer member be set small. However, if the elastic modulus is set small, it becomes difficult to transfer a large torque and it is very likely to exceed an elastic limit of the torque transfer member. Thus, the durability of the torque transfer member may be worsened.

In the rotary device such as a compressor or a pump for power steering, required torque required on the rotary device side changes greatly, so that torque acting on a torque transmitting member differs greatly between the case where a torque variation is absorbed in a state in which the required torque is large and the case where a torque variation is absorbed in a state in which the required torque is small.

Therefore, by such a simple way as merely disposing in a power transmission path a torque transmitting member made of an elastic material such as rubber, it is difficult to absorb a torque fluctuation sufficiently in both cases of the required torque being large and small.

SUMMARY OF THE INVENTION

An object of the present invention is to allow a transmission of large torque while absorbing a torque fluctuation to a satisfactory extent.

According to a first aspect of the present invention, a torque transmitting member is deformed mainly by a flexural deformation when the amount of deformation is less than a predetermined amount and is deformed mainly by a compressive deformation when the amount of deformation is more than the predetermined amount. An elastic modulus of the torque transmitting member at a time when an amount of deformation is larger than the predetermined amount becomes larger than that at a time when an amount of deformation is less than the predetermined amount.

Thus, when the transmission torque fed from the driving source to the rotary device is small, the elastic modulus of the torque transmitting member becomes small, so that a fluctuation of the transmitting torque can be absorbed to a satisfactory extent. On the other hand, when the transmitting torque is large, the elastic modulus of the torque transmitting member becomes large, so that the torque transmitting member can be prevented from exceeding its elastic limit.

Thus, not only the transmission of a large torque can be done while absorbing a torque fluctuation sufficiently but also the torque transmitting member can be prevented from exceeding its elastic limit, thereby improving the durability of the torque transfer member.

Here, the elastic modulus of the torque transmitting member represents a change rate, K (=.DELTA.T/.DELTA..theta.), of a transmission torque T transmitted between the first rotor and the second rotor relative to a relative rotational angle .theta. of the first rotor with respect to the second rotor.

According to a second aspect of the present invention, an elastically deformable elastic member is disposed between a first curved surface of first rotor and a second curved surface of second rotor, and the elastic member is compressed by first and second curved surfaces to transmit a torque from the first rotor to the second rotor. A radius of curvature and a center of curvature of the first curved surface and a radius of curvature and a center of curvature of the second curved surface are made different from each other. Therefore, a change rate of the distance between the first and second curved surfaces at a time when a relative rotational angle of the first rotor with respect to the second rotor exceeds a predetermined amount is larger than a change rate of the distance between the first and second curved surfaces at a time when the relative rotational angle exceeds the predetermined amount.

Thus, when the torque is imposed on the first rotor and the first rotor rotates relatively with respect to the second rotor, as the relative rotational angle (.theta.) increases, the amount of movement of the first curved surface toward the second curved surface increases.

Consequently, the change rate of the distance between the first and second curved surfaces at a time when the relative rotational angle exceeds the predetermined amount becomes larger than that at a time when the relative rotational angle is less than the predetermined amount. In this case, since the elastic member is disposed between the first and second curved surfaces, as the relative rotational angle increases, the amount of compressive deformation of the elastic member in a non-linear fashion increases. That is, the transmission torque transmitted from the first rotor to the second rotor increases in a non-linear manner as the relative rotational angle becomes larger.

Therefore, even if an elastic material having a relatively large elastic modulus is selected as the elastic member, it is possible to decrease the amount of deflection at a relative rotational angle less than the predetermined amount, so that an elastic material having a relatively large elastic modulus can be used for the elastic member.

Further, since it is possible to prevent the elastic member from exceeding its elastic limit when the transmission torque becomes large, it is possible to transmit a large torque while absorbing a torque variation sufficiently.

According to a third aspect of the present invention, an outer periphery of the second rotor is generally star-shaped so as to have a plurality of projections, with a smooth curved surface being formed between adjacent projections, pins each having a circumferential surface with a radius smaller than a radius of curvature of the curved surface are provided in the first rotor so as to be each positioned between adjacent projections. An elastically deformable elastic member is disposed on the curved surface.

Thus, as the relative rotational angle of the first rotor with respect to the second rotor increases, the amount of compressive deformation of the elastic member increases in a non-linear manner. That is, as the relative rotational angle increases, the transmission torque increases in a non-linear manner.

Thus, even if an elastic material having a relatively large elastic modulus is adopted for the elastic member, it is possible to decrease the amount of deflection at a relative rotational angle less than a predetermined value, so that an elastic material having a relatively large elastic modulus can be used for the elastic member.

Further, since it is possible to prevent the elastic member from exceeding its elastic limit when the transfer torque becomes large, it is possible to effect the transfer of a large torque while absorbing a torque variation sufficiently.

According to a fourth aspect of the present invention, a torque transmitting member is deformable elastically and includes first and second transmitting members accommodated within the same space and having respective portions generally parallel to a compressive load direction which are different in size. When a relative rotational angle of the first rotor with respect to the second rotor is less than a predetermined rotational angle, the its first transmitting member mainly transmits the torque by undergoing a compressive deformation. On the other hand, when the relative rotational angle exceeds the predetermined rotational angle, the first and second transfer members share each other in bearing a compressive load to transmit the torque.

Thus, the relation between the relative rotational angle and the torque transmitted from the first rotor to the second rotor has a non-linear characteristic such that the torque becomes large with the arrival of the relative rotational angle at the predetermined relative rotational angle as a turning point.

The compressive deformation rate as referred to herein means a change rate of the transfer torque with respect to the relative rotational angle. As the compressive deformation rate increases, the transmission torque T with respect to the relative rotational angle becomes large.

Thus, even if a large torque is imposed on the torque transmitting apparatus, it is possible to prevent the torque transmitting member from exceeding its elastic limit, so that a torque fluctuation can be absorbed sufficiently under the transmission of a large torque.

According to a fifth aspect of the present invention, a torque transmitting member is formed so that a change rate of the transmission torque with respect to a relative rotational angle of the first rotor at a time when the first rotor rotates by a first predetermined angle or more in a forward direction relative to the second rotor is larger than the change rate at a time when if the first rotor rotates by a second predetermined angle or less, which is smaller than the first predetermined angle, in a reverse direction relative to the second rotor.

Thus, even if the required torque of the rotary device is large, it is possible to transmit a large torque and absorb a torque fluctuation sufficiently while preventing the torque transmitting member from exceeding its elastic limit.

On the other hand, when the required torque is small, a torque fluctuation can be absorbed even if the change rate is small. Thus, even when the required torque is small, it is possible to absorb a torque fluctuation to a satisfactory extent.

As mentioned above, it is possible to transfer a large torque while absorbing a torque fluctuation to a satisfactory extent.

According to a sixth aspect of the present invention, first and second torque transmitting members are accommodated respectively within plural spaces formed in the circumferential direction within the first and second rotors. The first and second torque transmitting members are elastically deformable and undergo a compressive deformation to transmit the torque. Before compressive deformation of the second torque transmitting member, an inner wall of a space where the second torque transmitting member is accommodated, out of the plural spaces, is spaced by a predetermined gap from the second torque transmitting member in a compressive load direction. When the first torque transmitting member is compressively deformed by a predetermined amount or more, the predetermined distance vanishes and a compressive load is imposed on the second torque transmitting member.

Thus, when the torque is exerted on the first rotor and the first rotor rotates relatively with respect to the second rotor, only the first torque transmitting member is deformed compressively until the relative rotational angle reaches a predetermined relative rotational angle.

When the first torque transmitting member is compressively deformed by the predetermined amount or more and the relative rotational angle reaches the predetermined relative rotational angle, a compressive load is exerted also on the second torque transmitting member, so that both the first and second torque transmitting members are deformed compressively.

Thus, the relation between the relative rotational angle and the torque transmitted from the first rotor to the second rotor has a non-linear characteristic such that as the relative rotational angle increases, the compressive deformation rate of the torque transmitting member increases.

The compressive deformation rate as referred to herein means a change rate of the transmission torque with respect to the relative rotational angle.

Thus, even if a large torque is imposed on the torque transmitting apparatus, it is possible to prevent the torque transmitting member from exceeding its elastic limit, so that a torque fluctuation can be absorbed sufficiently under the transmission of a large torque.

According to a seventh aspect of the present invention, a torque transmitting member is deformable elastically and undergoes a compressive deformation to transmit the torque. When a relative rotational angle of the first rotor with respect to the second rotor is smaller than a predetermined rotational angle, the torque transmitting member undergoes a compressive deformation so that the cross-sectional area in a cross-section nearly perpendicular to the direction of a compressive load imposed on the torque transmitting member increases. When the relative rotational angle is smaller than the predetermined rotational angle, the torque transmitting member undergoes a compressive deformation while inhibiting an increase of the cross-sectional area.

In the case where the compressive deformation takes place so as to bring about an increase of the cross-sectional area, the freedom of the deformation is large in comparison with the case where the compressive deformation takes place in an increase-inhibited state of the cross-sectional area. A change rate (elastic modulus k) of the compressive load with respect to a relative rotational angle of the first rotor relative to the second rotor in case of the compressive deformation being done so as to result in an increase of the cross-sectional area is smaller than the elastic modulus k in case of the compressive deformation being done in an increase-inhibited state of the cross-sectional area.

Thus, the elastic modulus k) of the torque transmitting member at a large relative rotational angle is larger than that at a small relative rotational angle.

Thus, even if a large torque is imposed on the torque transmitting apparatus, it is possible to prevent the torque transmitting member from exceeding its elastic limit and hence possible to absorb a torque fluctuation sufficiently under the transmission of a large torque.

According to an eighth aspect of the present invention, a torque transmitting member accommodated within a space formed within the first and second rotors. The torque transmitting member is deformable elastically and undergoes a compressive deformation to transmit the torque. When a compressive load is not imposed on the torque transmitting member, a gap is formed between a portion of an inner wall of the space which is nearly parallel to the direction of the compressive load and the torque transmitting member.

Thus, when the relative rotational angle is small, the torque transmitting member is deformed compressively so as to increase the cross-sectional area thereof and thereby fill up the gap. After the gap has vanished, the torque transmitting member is compressively deformed in an increase-inhibited state of the cross-sectional area. Therefore, the elastic modulus k of the torque transmitting member is large when the relative rotational angle is large in comparison with the case where the relative rotational angle is small.

Thus, even if a large torque is exerted on the torque transmitting apparatus, it is possible to prevent the torque transmitting member from exceeding its elastic limit and hence possible to absorb a torque fluctuation sufficiently under the transmission of a large torque.

According to a ninth aspect of the present invention, a torque transmitting member accommodated within a space formed within first and second rotors, the torque transmitting member is deformable elastically and undergoes a compressive deformation to transmit the torque. An end portion of the torque transmitting member in a direction nearly parallel to the direction of a compressive load acting on the torque transmitting member is tapered so as to be smaller in cross-sectional area toward a front end side thereof. Therefore, when a compressive load is not imposed on the torque transmitting member, a gap is formed between an inner wall of the space and the torque transmitting member.

Thus, the torque transmitting member is deformed compressively so that the gap becomes smaller as the relative rotational angle increases from the state of it being zero. Thus, the torque transmitting member has a non-linear characteristic such that as the relative rotational angle increases, the elastic modulus k increases.

Therefore, even if a large torque acts on the torque transmitting apparatus, it is possible to prevent the torque transmitting member from exceeding its elastic limit and hence possible to absorb a torque fluctuation sufficiently under the transmission of a large torque.

According to a tenth aspect of the present invention, the torque transmitting member is deformable elastically and undergoes a compressive deformation to transmit the torque. The torque transmitting member is deformed compressively so that at least when a relative rotational angle of the first rotor with respect to the second rotor is smaller than a predetermined rotational angle, as the relative rotational angle increases, the area of contact between a portion of an inner wall of the space which is nearly parallel to the direction of the compressive load and the torque transmitting member increases.

Thus, the torque transmitting member is deformed compressively in such a manner that the freedom of deformation becomes smaller as the relative rotational angle increases from the state of it being zero. As a result, the torque transmitting member comes to have a non-linear characteristic such that as the relative rotational angle increases, the elastic modulus k of the torque transmitting member increases.

Thus, even if a large torque acts on the torque transmitting apparatus, the torque transmitting member can be prevented from exceeding its elastic limit and so it is possible to absorb a torque fluctuation to a satisfactory extent under the transmission of a large torque.

According to an eleventh aspect of the present invention, a torque transmitting member is accommodated within a space formed within first and second rotors. The torque transmitting member is deformable elastically and undergoes a compressive deformation to transmit the torque. When a compressive load is not imposed on the torque transmitting member, a gap is formed between an inner wall of the space and the torque transmitting member.

Thus, the torque transmitting member is deformed compressively so that the gap becomes smaller as the relative rotational angle increases from the state of it being zero. As a result, the torque transmitting member comes to have a non-linear characteristic such that as the relative rotational angle increases, the elastic modulus k thereof increases.

Thus, even if a large torque acts on the torque transmitting apparatus, it is possible to prevent the torque transmitting member from exceeding its elastic limit and hence possible to absorb a torque fluctuation to a satisfactory extent under the transmission of a large torque.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments thereof when taken together with the accompanying drawings in which:

FIG. 1 is a schematic view showing a refrigeration cycle for a vehicle air conditioner (first embodiment);

FIG. 2 is a cross-sectional view showing a pulley (first embodiment);

FIG. 3 is a front view showing a center hub (first embodiment);

FIG. 4 is a front view showing a pulley body (first embodiment);

FIG. 5 is an enlarged cross-sectional view showing a mounted state of a damper rubber (first embodiment);

FIG. 6 is a graph showing a relation between an amount of deformation and a compressive load (first embodiment);

FIG. 7 is a front view showing a modified example of the pulley body (first embodiment);

FIG. 3 is a front view showing a pulley body (second embodiment);

FIG. 9 is a front view showing a pulley body (third embodiment);

FIG. 10 is a schematic view showing a refrigeration cycle for a vehicle air conditioner (fourth embodiment);

FIG. 11 is a cross-sectional view showing a pulley (fourth embodiment);

FIG. 12 is a front view showing a pulley body (fourth embodiment);

FIG. 13 is a front view showing the pulley at a relative rotational angle of 0.degree. (fourth embodiment);

FIG. 14 is a front view showing the pulley at a relative rotational angle of 8.degree. (fourth embodiment);

FIG. 15 is a graph showing a relation between the relative rotational angle .theta. of the pulley and transmission torque (fourth embodiment);

FIG. 16 is a cross-sectional view showing a pulley (fifth embodiment);

FIG. 17 is a front view showing a pulley body (fifth embodiment);

FIG. 18 is a schematic view showing a refrigeration cycle for a vehicle air conditioner (sixth embodiment);

FIG. 19 is a cross-sectional view showing a pulley (sixth embodiment);

FIG. 20 is a front view showing a pulley body (sixth embodiment);

FIG. 21 is a graph showing characteristics of dampers (sixth embodiment);

FIG. 22 is a schematic view showing a refrigeration cycle for a vehicle air conditioner (seventh embodiment);

FIG. 23 is a cross-sectional view showing a pulley (seventh embodiment);

FIG. 24 is a front view showing a pulley body (seventh embodiment);

FIG. 25 is a characteristic diagram showing characteristics of a damper (seventh embodiment);

FIG. 26 is a front view showing a modified example of the pulley body (seventh embodiment);

FIG. 27A is a front view showing a pulley body (eighth embodiment);

FIG. 27B is a cross-sectional view showing the pulley body (eighth embodiment);

FIG. 28 is a schematic view showing a refrigeration cycle for a vehicle air conditioner (ninth embodiment);

FIG. 29 is a cross-sectional view showing a pulley (ninth embodiment);

FIG. 30 is a front view showing a pulley body (ninth embodiment);

FIG. 31 is a graph showing characteristics of a damper (ninth embodiment);

FIG. 32 is a front view showing a pulley body (tenth embodiment);

FIG. 33 is a front view showing a pulley body (eleventh embodiment);

FIG. 34 is a front view showing a pulley body (twelfth embodiment);

FIG. 35 is a schematic view showing a refrigeration cycle for a vehicle air conditioner (thirteenth embodiment);

FIG. 36 is a cross-sectional view showing a pulley (thirteenth embodiment);

FIG. 37 is a front view showing a pulley body (thirteenth embodiment);

FIG. 38 is a graph showing characteristics of a damper (thirteenth embodiment);

FIG. 39 is a front view showing a modified example of the pulley body (thirteenth embodiment);

FIG. 40A is a front view of showing a second modified example of the pulley body (thirteenth embodiment), and

FIG. 40B is a cross-sectional view taken along line 40B--40B in FIG. 40A.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(First Embodiment)

In the first embodiment, the present invention is applied to a torque transmitting apparatus for the transmitting a power from a vehicle engine to a compressor for a vehicular air conditioner. FIG. 1 is a schematic view showing a refrigeration cycle for the vehicle air conditioner.

A compressor 1 sucks and compresses a refrigerant. A condenser 2 cools the refrigerant discharged from the compressor 1. A pressure reducing device 3 reduces the pressure of the refrigerant flowing out of the condenser 2. An evaporator 4 evaporates the refrigerant pressure-reduced by the pressure reducing device 3, thereby allowing the refrigerant to cool an air passing through the evaporator 4.

Here, in the present embodiment, as the pressure reducing device 3, a thermostatic expansion valve is used for adjusting an opening degree thereof so that the refrigerant at an outlet side of the evaporator 4 has a predetermined superheat.

A pulley type torque transmitting apparatus 10 transmits a power of the engine E/G through a V belt 5 to the compressor 1. The pulley type torque transmitting apparatus 10 will be described.

FIG. 2 is a cross-sectional view showing the pulley type torque transmitting apparatus 10. A metal pulley body 11 includes V grooves 11 a for around which a V-belt 5 is hung. The pulley body 11 receives the driving force from the engine E/G and rotates.

A radial bearing 12 supports the pulley body 11 rotatably. An outer race 12a of the radial bearing is press-fitted and fixed into the pulley body 11, and a front housing of the compressor 1 is inserted into an inner race 12b. A radial load induced by the tension of the V belt 5 can be received by the front housing of the compressor 1 without being received by a shaft of the compressor.

A center hub 13 is connected to the shaft of the compressor 1 and adapted to rotate together with the shaft. As shown in FIG. 3, the center hub 13 includes a cylindrical portion 13a having a cylindrical inner peripheral surface which is splined for coupling with a splined outer peripheral surface of the shaft, an annular portion 13cformed with plural projections 13b which receive torque fed from the pulley body 11, and a bridge portion 13d which provides a mechanical connection between the annular portion 13c and the cylindrical portion 13a to transmit the torque from the annular portion 13c to the cylindrical portion 13a.

The strength of the bridge portion 13d is set at a value at which it breaks when the torque transferred from the annular portion 13c to the cylindrical portion 13a becomes a predetermined torque or higher. Thus, the bridge portion 13d functions as a torque limiter mechanism which limits a maximum torque capable of being transmitted from the engine E/G to the compressor 1. FIG. 2 shows that the torque limiter mechanism, or bridge portion 13d, is arranged in such a manner that the axial extent of the torque limiter mechanism is within the axial extent of the pulley 11.

The cylindrical portion 13a and the bridge portion 13d are made o metal and integrally formed. The annular portion 13c is formed by molding a resin, the bridge portion 13d and the annular portion 13c are integrally formed by insert molding.

At the portion of the pulley body 11 corresponding to the annular portion 13c, there are formed plural projections 11b integrally so as to project from the pulley body 11 toward the annular portion 13c as shown in FIG. 4. Each projection 11b radially and inwardly extends from an outer annular portion 11e of the pulley body 11 to an inner annular portion 11f of the pulley body 11, which is radially and inwardly spaced from the outer annular portion 11e. With the pulley body 11 and the center hub 13 mounted on the compressor 1, the projections 13b of the center hub 13 and the projections 11b of the pulley body 11 are positioned alternately around the shaft, as shown in FIG. 5.

Between both adjacent projections 11b and 13b, a damper rubber 14 is disposed. The damper rubber 14 is made of EPDM (ethylene-propylene-diene terpolymer rubber) in the present embodiment for being deformed elastically. The damper rubber 14 transmits the torque received by the pulley body 11 to the center hub 13.

The damper rubber 14 includes a damper body 14d. The damper body 14d includes a first deforming portion 14b having a hole 14a and a second deforming portion 14c having no hole 14a. The hole 14a is reduced in cross-sectional area nearly perpendicular to a compressive load direction. Two such damper bodies 14d are interconnected by a connecting member 14h as one set, which set is inserted between projections 11b and 13b at plural positions, as shown in FIGS. 4 and 5.

When the pulley body 11 rotates, as shown in FIG. 4, the pulley body 11 shifts its position so as to reduce the size between both projections 11b and 13b (see arrow), so that a compressive force acts on the damper rubber 14.

At this time, since the hole 14a is formed in the first deforming portion 14b, when a compressive load is imposed on the damper rubber 14, pillar portions 14e of the hole 14a which are nearly parallel to the load direction undergo a flexural deformation so as to result in buckling deformation.

As the compressive load further increases and the buckling deformation of the pillar portions 14e becomes more conspicuous, the hole 14a collapses and the damper rubber 14 undergo a compressive deformation so as to collapse itself. At this time, the buckling deformation proceeds at a relatively small compressive load, while the compressive deformation requires a larger compressive load in comparison with the buckling deformation.

Thus, when the amount of deformation is not more than a predetermined amount, the damper rubber 14 is deformed mainly by a flexural deformation. On the other hand, when the amount of deformation exceeds the predetermined amount, the damper rubber 14 is deformed mainly by a compressive deformation. Thus, as shown in FIG. 6, the damper rubber 14 undergoes an elastic deformation so as to have a non-linear characteristic such that an elastic modulus of the damper rubber at an amount of deformation exceeding the predetermined amount is larger than that at an amount of deformation not more than the predetermined amount.

The elastic modulus of the damper rubber 14 represents a change rate, K (where K=.DELTA.T/.DELTA..theta., T represents torque, and .theta. represents the rotational angle), of a transfer torque transferred between the pulley body 11 and the center hub 13 relative to the relative rotational angle of the pulley body 11 with respect to the center hub 13.

Therefore, when the transmission torque fed from the engine E/G to the compressor 1 is small, the elastic modulus of the damper rubber 14 becomes small and hence it is possible to absorb a variation of the transfer torque sufficiently. On the other hand, when the transfer torque is large, the elastic modulus of the damper rubber 14 is large and hence it is possible to prevent the damper rubber 14 from exceeding its elastic limit.

Besides, since not only the transfer of a large torque can be attained while absorbing a variation of torque sufficiently but also it is possible to prevent the damper rubber 14 from exceeding its elastic limit, it is possible to improve the durability of the damper rubber 14.

Further, since a non-liner characteristic can be obtained with simple constitution such that the hole 14a is formed in a damper rubber 14, the manufacturing cost of the pulley type torque transmitting apparatus 10 is reduced while attaining the transfer of a large torque under sufficient absorption of a torque variation.

The shape of the hole 14a in the present embodiment is not limited to such a loofah shape as shown in FIG. 4, but it may be, for example, a triangular shape as shown in FIG. 7.

(Second Embodiment)

In the second embodiment, as shown in FIG. 8, a damper rubber 14 is formed in S shape so as to extent in a compressive load direction while meandering, thereby affording a non-linear characteristic.

In the second embodiment, when the compressive load is not more than a predetermined amount, beam portions 14f undergo a flexural deformation like compression of a coiled spring, and when the compressive load exceeds the predetermined amount, the beam portions 14f undergo a compressive deformation so that the damper rubber 14 itself collapse in a closely contacted state of the beam portions 14f. The beam portions 14f indicate portions extending from bent portions 14g in a direction perpendicular to the compressive load direction.

At this time, a buckling deformation proceeds at a relatively small compressive load, while the compressive deformation requires a large compressive load in comparison with the buckling deformation, thereby obtaining a non-linear characteristic.

In the second embodiment, two bent portions 14g are formed to afford an S shape. Alternatively, only one bent portion 14g may be formed to afford a V shape, or three or more bent portions 14g may be formed.

Further, since a non-linear characteristic can be obtained by such a simple constitution as forming the damper rubber 14 in S shape, the manufacturing cost of the pulley type torque transmitting apparatus 10 can be reduced while attaining the transfer of a large torque under sufficient absorption of a torque variation.

(Third Embodiment)

All of plural damper rubbers 14 used in the above first and second embodiments are of the same characteristic, but in the third embodiment, as shown in FIG. 9, two types of dampers 14A and 14B different in characteristic are used to obtain a desired characteristic.

The damper 14A has the same shape and characteristic as the damper rubber 14 used in the first embodiment. Meanwhile, as shown in FIG. 9, an end portion of the damper 14B in the rotational direction of the pulley body 11 is tapered so that the cross-sectional area thereof becomes smaller toward the front end side thereof. When the relative rotational angle .theta. of the pulley body 11 with respect to the center hub 13 is smaller than a predetermined rotational angle .theta.1, the damper 14B undergoes a compressive deformation so that the sectional area of a section of the damper 14B perpendicular to the compressive load direction increases. On the other hand, when the relative rotational angle .theta. is not less than the predetermined rotational angle .theta.1, the damper 14B undergoes a compressive deformation in a state in which an increase of the sectional area is inhibited by a space 11c and an inner wall 11d.

In the case where the damper 14B undergoes a compressive deformation so as to induce an increase of the cross-sectional area, the degree of freedom of the deformation is larger than in the case where the damper 14B undergoes a compressive deformation in an increase-inhibited state of the cross-sectional area, so that the elastic modulus of the damper 14B in the former case is smaller than that in the latter case.

Thus, when the relative rotational angle .theta. of the pulley body 11 is smaller than the predetermined rotational angle .theta.1, the damper 14B undergoes a compressive deformation so that the area of contact between the space 11c (inner wall 11d) and the damper 14B increases as the relative rotational angle .theta. increases. Thus, the damper 14B comes to have a non-linear characteristic such that the larger the relative rotational angle .theta., the larger the elastic modulus of the damper.

In the third embodiment, the damper 14B has a non-linear characteristic. Alternatively, the damper 14B may have a linear characteristic.

In the above-described first through third embodiments, the damper rubber 14 is made of EPDM. Alternatively, the damper rubber 14 may be formed using another material, e.g., elastomer, resin, or metal.

In the above-described first through third embodiments, the present invention is applied to the pulley type torque transmitting apparatus 10 which transmits the torque to the compressor 1. Alternatively, the present invention may be applicable to any other torque transmitting device.

In the above-described first through third embodiments, the hole 14a is a through hole. Alternatively, the hole 14a may be a recess or the like which is not a through hole.

(Fourth Embodiment)

In the fourth embodiment, the present invention is applied to a torque transmitting apparatus for the transmitting a power from a vehicle engine to a compressor for a vehicular air conditioner. FIG. 10 is a schematic view showing a refrigeration cycle for the vehicle air conditioner.

A compressor 101 sucks and compresses a refrigerant. A condenser 102 cools the refrigerant discharged from the compressor 101. A pressure reducing device 103 reduces the pressure of the refrigerant flowing out of the condenser 102. An evaporator 104 evaporates the refrigerant pressure-reduced by the pressure reducing device 103, thereby allowing the refrigerant to cool an air passing through the evaporator 104.

Here, in the present embodiment, as the pressure reducing device 103, a thermostatic expansion valve is used for adjusting an opening degree thereof so that the refrigerant at an outlet side of the evaporator 104 has a predetermined superheat.

A pulley type torque transmitting apparatus 110 transmits a power of the engine E/G through a V belt (not illustrated) to the compressor 101. The pulley type torque transmitting apparatus 110 will be described.

FIG. 11 is a cross-sectional view showing the pulley type torque transmitting apparatus 110. A metal pulley body 111 includes V grooves 111a for around which a V-belt is hung. The pulley body 111 receives the driving force from the engine E/G and rotates.

A radial bearing 112 supports the pulley body 111 rotatably. An outer race 112a of the radial bearing 112 is press-fitted and fixed into the pulley body 111 and a cylindrical portion 101b formed in a front housing 101a of the compressor 101 is inserted into an inner race 112b. Thus, a radial load induced by the tension of the V belt can be received by the front housing 101a of the compressor 101 without being received by a shaft 101c of the compressor 101.

A center hub 113 is connected to the shaft 101c of the compressor 101 and adapted to rotate together with the shaft 101c. The center hub 113 is disposed coaxially with the pulley body 111.

The center hub 113 includes a cylindrical portion 113a having a cylindrical inner peripheral surface formed with internal threads for coupling with external threads formed on an outer peripheral surface of the shaft 101c, and: a flange portion 113c formed in a star shape so as to have plural projections 113b on its outer periphery, as shown in FIG. 12. The cylindrical portion 113a and the flange portion 113c are made of metal and integrally formed.

Between adjacent projections 113b, a smooth curved surface 113d having a radius of curvature larger than the radius of a roller 115 is formed. A damper 114 (hatched portion in FIG. 12) made of elastically deformable material (EPDM (ethylene propylene diene terpolymer rubber) is disposed on the curved surface 113d.

In the present embodiment, a recess 113e, which is concave on the cylindrical portion 113a side, is formed within the curved surface 113, while a protrusion 114a to be fitted in the recess 113e is formed on the damper 114, to prevent displacement of the damper 114 relative to the flange portion 113c. Therefore, when the damper 114 is bonded to the curved surface 113d by a bonding method such as adhesion by vulcanization, the recess 113e and the protrusion 114a may be omitted.

The metallic roller 115 is formed so as to have a circumferential surface with a radius of curvature r1 smaller than a radius of curvature r2 of the curved surface 113d. As shown in FIG. 11, the roller 115 is rotatably supported by the pulley body 11 so as to be positioned between adjacent projections 113b through a pin 115a which is press-fitted and fixed into the pulley body 111. An E-shaped retaining ring 115c prevents the roller 115 from coming off the pin 115a.

In the fourth embodiment, with an outer peripheral surface 115b and the curved surface 113d opposed to each other, the radius of curvature r1 of the outer peripheral surface 115b ("first curved surface 115b" hereinafter) of the roller 115 and a center of radius O1 thereof, and the radius of curvature r2 of the curved surface 113d ("the second curved surface 113d" hereinafter) and a center of curvature O2 thereof, are different from each other, the first curved surface 115b is positioned on a more radially outer side than the second curved surface 113d, and both curved surfaces 115b and 113d are convex toward a rotational center side of the pulley body 111 and the center hub 113.

In the fourth embodiment, as noted above, the radius of curvature r1 of the first curved surface 115b and the center of curvature O1 thereof, and the radius of curvature r2 of the second curved surface 113d and the center of curvature O2 thereof, are different from each other, so that the first curved surface 115b is positioned on a more radially outer side than the second curved surface 113d, and both curved surfaces 115b and 113d are convex toward the rotational center side of the pulley body 111 and the center hub 113. Thus, torque is imposed on the pulley body 111, and when the pulley body 111 rotates relatively with respect to the center hub 113, the larger the relative rotational angle .theta., the larger the amount of movement of the first curved surface 115b toward the second curved surface 113d, as shown in FIGS. 13 and 14.

Here, FIG. 13 shows a state in which torque is not exerted on the pulley body 111 (the relative rotational angle .theta. of the pulley body 111 with respect to the center hub 113 is 0.degree.). FIG. 14 shows a state in which torque is exerted on the pulley body 111 (the relative rotational angle .theta. is, for example, about 8.degree.).

Thus, the change rate of the distance .delta. between both curved surfaces 115b and 113d detected when the relative rotational angle .theta. exceeds the predetermined value becomes larger than that detected when the relative rotational angle .theta. is not more than the predetermined amount. In this connection, since the rubbery damper 114 is disposed between both curved surfaces 115b and 113d, the amount of compressive deformation of the damper 114 increases non-linearly as the relative rotational angle .theta. becomes larger. That is, as shown in FIG. 15, the transmission torque transmitted from the pulley body 111 to the center hub 113 becomes larger non-linearly as the relative rotational angle .theta. becomes larger.

Therefore, even if a rubber having a relatively large elastic modulus is selected for the material of the damper 114, the amount of deflection at a relative rotational angle .theta. of not more than the predetermined value can be: made small and therefore rubber having a relatively large elastic modulus can be adopted for the damper 114.

Further, since it is possible to prevent the damper 114 from exceeding its elastic limit when the transfer torque becomes large, the transfer of a large torque can be done while absorbing a torque fluctuation sufficiently.

(Fifth Embodiment)

In the fourth embodiment, roller 115 which is rotating and the damper 114 are brought into contact with each other. However, in the present fifth embodiment, as shown in FIGS. 16 and 17, the roller 115 is omitted and instead an outer peripheral surface of a pin 115a is brought into contact with the damper 114. In the present fifth embodiment, the outer peripheral surface of the pin 115a corresponds to the first curved surface 115b.

Here, a film (e.g., Teflon sheet) having a small frictional coefficient is affixed to the surface of the damper 114 which comes into contact with the outer peripheral surface (the first curved surface 115b) of the pin 115a, thereby allowing the damper 114 and the outer peripheral surface (the first curved surface 115b) of the pin 115a to slide smoothly with respect to each other.

In the above-described fourth and fifth embodiments, the damper 114 is positioned between the first and second curved surfaces 115b and 113d by disposing the damper 114 on the second curved surface 113d. Alternatively, the damper 114 may be positioned between the first and second curved surfaces 115b and 113d by winding the damper 114 around the first curved surface 115b (the outer peripheral surface of the roller 115 or of the pin 115a).

In the above-described fourth and fifth embodiments, the damper 114 is made of rubber (EPDM). Alternatively, the damper 114 may be made of any other material such as, for example, resin or metal.

In the above-described fourth and fifth embodiments, the present invention is applied to the pulley type torque transmitting apparatus 10 for transmitting the torque to the compressor 101. Alternatively, the present invention may be applied to any other torque transmitting device.

In the above-described fourth and fifth embodiments, the roller 115 and the flange portion 113c are made of metal. Alternatively, the roller a15 and the flange portion 113c may be made of other material such as resin.

In the above-described fourth and fifth embodiments, the torque is transmitted from the pulley body 111 to the center hub 113. The present invention is also applicable to the case where torque is transmitted from the center hub 113 to the pulley body 111.

Further, the present invention is applicable to a pulley with torque limiter mechanism for preventing the transmission of an excessive torque caused by, for example, breakage of the flange portion 113c at a predetermined or larger value of the transmitting torque.

(Sixth Embodiment)

In the sixth embodiment, the present invention is applied to a torque transmitting apparatus for the transmitting a power from a vehicle engine to a compressor for a vehicular air conditioner. FIG. 18 is a schematic view showing a refrigeration cycle for the vehicle air conditioner.

A compressor 201 sucks and compresses a refrigerant. A condenser 202 cools the refrigerant discharged from the compressor 201. A pressure reducing device 203 reduces the pressure of the refrigerant flowing out of the condenser 202. An evaporator 204 evaporates the refrigerant pressure-reduced by the pressure r