Title: Case and electric motor having an engaging opening and deformable band and for producing the electric motor
Abstract: An electric motor comprises a yoke in which permanent magnets are held, the yoke including a cylindrical yoke body having a bottom and an auxiliary yoke in which the yoke body is fitted, at least one engaging opening provided in one of said yoke body and auxiliary yoke and a deformable band provided in the other of said yoke body and auxiliary yoke. The deformable band is fitted in the engaging opening in a state that the yoke body and auxiliary yoke are fitted.
Patent Number: 6,984,905 Issued on 01/10/2006 to Sano, et al.
| Inventors:
|
Sano; Narihito (Tokyo, JP);
Uchino; Setsuya (Tokyo, JP);
Ohira; Shigenori (Tokyo, JP)
|
| Assignee:
|
Calsonic Kansei Corporation (Tokyo, JP)
|
| Appl. No.:
|
651101 |
| Filed:
|
August 29, 2003 |
Foreign Application Priority Data
| Sep 17, 2002[JP] | 2002-269411 |
| Current U.S. Class: |
310/89; 29/596; 29/505 |
| Current Intern'l Class: |
H02K 5/04 (20060101); H02K 23/04 (20060101); H02K 5/16.7 (20060101); H02K 1/12 (20060101) |
| Field of Search: |
310/89
29/505,596,516,521
220/682
285/382
|
References Cited [Referenced By]
U.S. Patent Documents
| 3234414 | Feb., 1966 | Konijnenberg et al.
| |
| 4335323 | Jun., 1982 | Kebbon et al.
| |
| 4548334 | Oct., 1985 | Huber et al.
| |
| 5255938 | Oct., 1993 | Brede et al.
| |
| 6191516 | Feb., 2001 | Froehlich et al.
| |
| 6359363 | Mar., 2002 | Foerstera et al.
| |
| 2004/0169428 | Sep., 2004 | Sano et al.
| |
| Foreign Patent Documents |
| 4-190646 | Jul., 1992 | JP.
| |
| 2793653 | Jun., 1998 | JP.
| |
Other References
Patent Abstracts of Japan, vol. 015, No. 029, Jan. 23, 1991, JP 02-273046, Nov.
7, 1990.
Patent Abstracts of Japan, vol. 009, No. 065, Mar. 26, 1985, JP 59-201644, Nov.
15, 1984.
Patent Abstracts of Japan, vol. 015, No. 284, Jul. 18, 1991, JP 03-098434, Apr.
24, 1991.
Patent Abstracts of Japan, vol. 018, No. 635, Dec. 5, 1994, JP 06-245452, Sep.
2, 1994.
|
Primary Examiner: Tamai; Karl
Attorney, Agent or Firm: Foley & Lardner, LLP
Claims
What is claimed is:
1. A case comprising:
an outer cylindrical member;
an inner cylindrical member fitted in said outer cylindrical member;
at least one engaging opening provided in one of said inner and outer cylindrical members;
a deformable band provided in the other of said inner and outer cylindrical members
for inserting into said engaging opening; and
a positioning mechanism provided between said inner and outer cylindrical members
to face said deformable band to said engaging opening,
wherein said positioning mechanism has a stopper provided on one of said inner
and outer cylindrical members, to contact with the other of the inner and outer
cylindrical members, and a protrusion provided on the other of said inner and outer
cylindrical members to contact with said stopper.
2. The case according to claim 1, wherein said deformable band includes a plurality
of inclined surfaces which are contacted with edges of said engaging opening to
impart a pressed force axially and peripherally of the inner or outer cylindrical member.
3. The case according to claim 1, wherein said deformable band includes inclined
surfaces which are contacted with the edges of the engaging opening to impart a
pressed force thereto so as to contact the stopper with the other of the inner
and outer cylindrical members.
4. An electric motor comprising:
a yoke in which permanent magnets are held,
said yoke including a cylindrical yoke body having a bottom and an auxiliary
yoke in which said yoke body is fitted;
at least one engaging opening provided in one of said yoke body and auxiliary yoke;
a deformable band provided in the other of said yoke body and auxiliary yoke,
wherein said deformable band is fitted in said engaging opening in a state that
said yoke body and auxiliary yoke are fitted; and
a positioning mechanism provided between said yoke body and auxiliary yoke to
face said deformable band to the engaging opening,
wherein said positioning mechanism includes a stopper provided on said auxiliary
yoke, to contact with a portion of said yoke body, and a protrusion provided on
said yoke body to contact with said stopper.
5. The electric motor according to claim 4, wherein said deformable band includes
a plurality of inclined surfaces which are contacted with edges of said engaging
opening to impart a pressed force thereto axially and peripherally of the yoke
body or auxiliary yoke.
6. The electric motor according to claim 4, wherein said deformable band includes
inclined surfaces which are contacted with the edges of the engaging opening to
impart thereto a pressed force so as to contact the stopper with the yoke body.
7. A method for producing an electric motor, comprising the steps of:
fitting a cylindrical yoke body into a cylindrical auxiliary yoke;
rotating said auxiliary yoke relative to said yoke body;
facing a deformable band provided on one of said auxiliary yoke and yoke body
to an engaging opening provided on the other of said auxiliary yoke and yoke body
by abutting a stopper provided on one of said auxiliary yoke and yoke body with
a protrusion provided on the other of the auxiliary yoke and yoke body; and
inserting said deformable band into said engaging opening.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a case and an electric motor which is used to
rotate a blower fan in an air conditioner for an automobile for carrying out cooling
and heating in a passenger room of the automobile, for example, and a method for
producing the electric motor.
2. Description of the Prior Art
In general, there is known a case having an outer cylindrical member and an inner
cylindrical member fitted in the outer cylindrical member.
A lock means is required to lock the inner and outer cylindrical members. Conventionally,
the lock means is complicate in structure and an operation for locking is not easy.
On the other hand, there is known an electric motor
1 as shown in FIG.
17 (see, for example, Japanese Patent Laid-Open No. 4-190646, pages 1 to 2, FIG. 2).
The electric motor
1 includes permanent magnets
2 for generating
a magnetic flux and a cylindrical yoke
3 or a case on whose inner peripheral
wall the permanent magnets
2 is held.
The yoke
3 has an inner cylindrical member or a cylindrical yoke body
4 having a bottom and an outer cylindrical member or an auxiliary yoke
5
fitted in an inner peripheral wall of the yoke body
4.
The auxiliary yoke
5 is mainly formed by a pressed-processing to have
a thin wall thickness and is used to conduct an attenuation of a magnetic flux
leaked from the yoke body
4.
The auxiliary yoke
5 has also at an outer peripheral wall thereof a slit
5c extending from one end, an upper end
5a to the other
end, a lower end
5b to enlarge peripherally the auxiliary yoke
5,
as shown in FIG. 18.
The auxiliary yoke
5 is enlarged peripherally by provision of the slit
5c and fitted on the yoke body
4 to surround it. In other
words, the yoke body
4 is inserted into the auxiliary yoke
5.
In addition, the auxiliary yoke
5 is provided with slits
5d
which
are opened at the upper and lower ends
5a and
5b of
the auxiliary yoke
5, respectively to eliminate a leaked magnetic flux in
the electric motor
1.
There is also known an electric motor that a cylindrical auxiliary yoke is
fixed to a cylindrical yoke body by press-fitting the yoke body into the auxiliary
yoke or welding them (see, for example, Japanese Patent No. 2793653, page 4, FIG. 3).
However, in each of the aforementioned electro motors, there is a problem
that a position of the auxiliary yoke is not stable by it being moving on the yoke
body
4 since the auxiliary yoke
5 holds merely the yoke body
4.
Further, the position of the auxiliary yoke is not necessarily stable even
though the yoke body is press-fitted in the auxiliary yoke and if the auxiliary
yoke is welded to the yoke body, processes of assembling the auxiliary yoke and
yoke body are increased because of addition of a welding process.
Under such circumstances, it is considered that an auxiliary yoke
7
is fixed to a yoke body
6, for example, by engagement of an engaged piece
7a provided on the auxiliary yoke
7 into an engaged opening
6a provided in the yoke body
6, as shown in FIGS. 19 and 20.
However, in the structure, there is a possibility that the engaged piece
7a slides under a pressure on the outer peripheral wall of the yoke
body
6 until it reaches the engaging opening
6a to thus form
a scratch on the peripheral wall of the yoke body.
SUMMARY OF THE INVENTION
The present invention is made in view of the above problems and it is, therefore,
an object of the present invention to provide a case and an electric motor and
a method for producing the electric motor, capable of assembling easily.
To accomplish the object, a case according to a first aspect of the present invention
comprises an outer cylindrical member, an inner cylindrical member fitted in the
outer cylindrical member, at least one engaging opening provided in one of the
outer and inner cylindrical members, a deformable band provided in the other of
the outer and inner cylindrical members for inserting into the engaging opening
and a poisoning mechanism provided on the outer and inner cylindrical members to
face the deformable band to the engaging opening.
In one embodiment, the positioning mechanism includes a stopper provided on one
of the outer and inner cylindrical members to contact with a portion of the other
of the outer and inner cylindrical members and a protrusion provided on the other
of the outer and inner cylindrical members to contact with the stopper.
An electric motor according to a second aspect of the present invention comprises
a yoke in which permanent magnets are held, the yoke including a cylindrical yoke
body having a bottom and an auxiliary yoke in which the yoke body is fitted, at
least one engaging opening provided in one of the yoke body and auxiliary yoke
and a deformable band provided in the other of the yoke body and auxiliary yoke.
The deformable band is fitted in the engaging opening in a state that the yoke
body and auxiliary yoke are fitted.
In this case, a positioning mechanism is provided between the yoke body and auxiliary
yoke to face the deformable band to the engaging opening.
The deformable band is provided with a plurality of inclined surfaces adapted
to contact with edges of the engaging opening to impart a pressed force axially
and peripherally of the yoke body or auxiliary yoke.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention
will become more apparent from the following description taken in connection with
the accompanying drawings, in which:
FIG. 1 is a sectional view showing an electric motor according to a first embodiment
of the present invention.
FIG. 2 is a side view of a yoke body in the electric motor.
FIG. 3 is a bottom view of the yoke body.
FIG. 4 is a perspective view of the yoke body.
FIG. 5 is a side view of an auxiliary yoke in the electric motor.
FIG. 6 is a perspective view of the auxiliary yoke.
FIG. 7 is an operational view showing a state that deformable bands according
to the present invention impart a pressed force to edges of an engaging opening.
FIG. 8 is a bottom view of the auxiliary yoke.
FIG. 9 is an explanatory view showing a process of assembling the electric motor.
FIG. 10 is a bottom view of a yoke in the electric motor.
FIG. 11 is a side view of the yoke.
FIG. 12 is a sectional view of the yoke taken along the line A—A in FIG. 10.
FIG. 13 is a sectional view of the yoke taken along the line B—B in FIG. 11.
FIG. 14 is a perspective view of the yoke.
FIG. 15 is a side view of a yoke in a second embodiment.
FIG. 16 is a side view of a yoke in a third embodiment.
FIG. 17 is a sectional view of a first conventional electric motor.
FIG. 18 is a perspective view of an auxiliary yoke in the first conventional
electric motor.
FIG. 19 is a side view of a second conventional electric motor.
FIG. 20 is a sectional view taken along the line C—C in FIG. 19.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Some embodiments of the present invention will be explained with reference to
the accompanying drawings below.
A first embodiment of an electric motor
10 according to the present invention
will be first described referring to FIGS. 1 to 13. As shown in FIG. 1, the electric
motor
10 is mainly composed of a pair of permanent magnets
11 and
11, a cylindrical yoke
12 on an inside wall
12 of which the
permanent magnets are held, a bearing housing
15 disposed to cover a lower
opening of the yoke
12, a rotational driving shaft
16 passing through
a center of the yoke
12, a rotor
18 fixed in a periphery of a middle
part of the rotational driving shaft
16 and a mounting bracket
22
to fix the yoke
12 and bearing housing
15 to a mounting object such
as a panel.
The permanent magnets
11 and
11 are positioned in an axial middle
part substantially of the yoke
12 and held to oppose each other.
The yoke
12 includes a cylindrical yoke body
13 which has at one
end (an upper end in FIG. 1) a bottom
13a which is attached integrally
to the body and a cylindrical auxiliary yoke
14 fitted in a peripheral wall
13b of the yoke body
13.
As shown in FIG. 2, the bottom
13a of the yoke body
13 has
a substantially conical shape as viewed from a side surface.
As shown in FIG. 3, a plurality of exhaust holes
13c are arranged
with a constant space respectively in the same distance from a center of the bottom
13a to exhaust air for cooling. A portion of the bearing housing
15 is provided with an air suction hole
15a for supplying
the air for cooling within the yoke
12. A central part of the bottom
13a
is projected downwardly in an inverted hat-like shape, as shown in FIG. 1.
It is noted that at least one engaging opening is provided in one of peripheral
walls of the yoke body
13 and auxiliary yoke
14. In this embodiment,
two rectangular engaging openings
13d and
13d are formed
in the peripheral wall of the yoke body
13, as shown in FIG. 4. The engaging
openings
13d and
13d are arranged to oppose each other
across a central axis of the yoke body
13.
A lower end
13e of the yoke body
13 is provided with downwardly
projecting protrusions
13f which are adapted to be capable of locking
the bearing housing
15. As shown in FIGS. 5 and 6, the auxiliary yoke
14
has a slit
14c extending from an upper edge
14a to
a lower edge
14b to enlarge peripherally. The auxiliary yoke
14
has an elasticity so that the auxiliary yoke can be enlarged peripherally by the
slit
14c while can be reduced in the original shape by the elasticity.
Further, at least one deformable band is provided in the other of the peripheral
walls of the yoke body
13 and auxiliary yoke
14 to engage in the
least one engaging opening. In this embodiment, two deformable bands
14d
are formed on the peripheral wall of the auxiliary yoke
14 to engage
in the engaging openings
13d. These deformable bands
14d
are arranged to oppose each other across a central axis of the auxiliary yoke
14. Each of the deformable bands
14d is formed between a pair
of adjacent trapezoidal cutouts S and S and has a elongated rectangular central
bridged portion
14d1 and a pair of trapezoidal portions
14d2
and
14d2 which are arranged in right and left sides of the
central bridged portion as viewed from FIG.,
7.
The central bridged portion
14d1 in each deformable band
14d has an elasticity and is deformable to insert in and remove from
the corresponding engaging opening
13d.
A width H
1 of each of the central bridged portions
14d1
is less than a width H
2 of the engaging opening
13d.
Further, the maximum width H
3 of each deformable band
14d
is large than the width H
2 of the corresponding engaging opening
13d.
Inclined surfaces
14d3 are provided on the both sides
of the central bridged portion
14d1 to form the trapezoidal
portions
14d2. The opposed inclined surfaces on each side
of the central bridged portion are set to widen a space between the opposed inclined
surfaces according to go away from the central bridged portion. In other words,
each deformable band
14d is provided with a set of inclined surfaces
14d3 which is arranged on each side of the central bridged
portion
14d1.
Consequently, when the central bridged portion
14d1
of each deformable band is inserted into the corresponding engaging opening
13d,
the engagement of the central bridged portion and engaging opening is held and
the four inclined surfaces
14d3 are adapted to impart a pressed
force to edges of the engaging opening
13d by means of the elasticity
occurred by the slit
14c of the auxiliary yoke
14.
Further, a lower edge
14b of the auxiliary yoke
14
is provided with stoppers
14f and
14f arranged to oppose
each other across the central axis of the auxiliary yoke, as shown in FIG. 9. Each
of the stoppers
14f has a L-letter shape which a vertical portion
extending downwardly from the a lower end of the auxiliary yoke
14 and a
horizontal portion extending from a lower end of the vertical portion to the central
axis of the auxiliary yoke. When the auxiliary yoke
14 is moved on the peripheral
wall
13b of the yoke body
13 in an upper direction as shown
by arrow Y in FIG. 9, the stoppers stop the movement of the auxiliary yoke
14
by abutment of the stoppers with the lower end
13e of the yoke body
13. When the auxiliary yoke
14 is rotated relative to the yoke body
13 in a direction as shown by arrow Z in FIG. 9, it is rotated by sliding
between the stoppers
14f and the lower end of the
13e of
the yoke body
13 and then the stoppers are abutted with the protrusions
13f to stop the rotation of the auxiliary yoke
14.
When the stoppers
14f are abutted with the protrusions
13f
of the yoke body
13, the deformable bands
14d are disposed
to face to the engaging openings
13.
In this way, the electric motor
10 is configured in such a manner that
the auxiliary yoke
14 is fitted on the yoke body
13 in such a manner
that the central bridged portions
14d1 are inserted into the
engaging openings
13d, respectively and inclined surfaces
14d3
press the edges of the engaging openings
13d (see FIG. 1)
The bearing housing
15 is engaged with the protrusions
13f of
the yoke body
13.
The rotational driving shaft
16 is rotatably supported by bearings
17
and
17 provided in central parts of the bottom
13a of the
yoke body
13 and bearing housing
15.
The rotor
18 is fixed on an intermediate part of the rotational driving
shaft
16. The rotor
18 is composed of a core
18a made
of laminated steel plates, a plurality of slots
18b provided peripherally
of an outer peripheral wall of the core
18a and coils
18c
wound around the slots.
Further, a commutator
19 is attached on the rotational driving shaft
16 between the rotor
18 and bearing housing
15 to pass an
electrical power to the coils
18c. Disposed to face the commutator
19 are two blush holders
20 which are made of an insulting material
such as plastic resin. The blush holders are connected with a blush substrate (not
shown). A brush
21 is disposed within each of the brush holders
20
to be movable radially of a yoke
12. The brush
21 is electrically
connected with a coupler terminal (not shown) provided on an outer peripheral wall
of each yoke
12.
Each brush
21 is biased toward the commutator
19 by a spring
20a
supported in each of the brush holders
20 to contact resiliently an
inner end of the brush
21 with an outer peripheral wall of the commutator
19.
The mounting bracket
22 has a cylindrical bracket body
22a in
which the yoke
12 is fitted, a bottom
22b and a flange
22c
extending radially from the bracket body
22a. The electric motor
10 can be fixed to the mounting object by fixing the flange
22c
to the mounting object.
In addition, the bracket body
22a is provided with a hole
22d
for communicating with the air suction hole
15a of the bearing
housing
15.
Subsequently, an assembled method of the electric motor as described
above will be explained below.
The permanent magnets
11 and
11 are first held on the inner peripheral
wall of the yoke body
13 and then the auxiliary yoke
14 is fitted
on the outer peripheral wall of the yoke body
13 by matching the upper edge
14a of the auxiliary yoke with the lower end
13e of
the yoke body
13 and sliding upwardly the auxiliary yoke
14 along
the outer peripheral wall of the yoke body
13 as shown in FIG. 9. The upper
movement of the auxiliary yoke
14 is stopped by the abutment of the stoppers
14f of the auxiliary yoke
14 with the lower end
13e
of the yoke body
13.
The auxiliary yoke
14 is then rotated relative to the yoke body
13
in the direction as shown by the arrow Z in FIG. 9. During the rotation of the
auxiliary yoke
14, the stoppers
14f are abutted with the protrusions
13f of the yoke body
13 as shown in FIGS. 10 and 12 to stop
the rotation of the auxiliary yoke
14 relative to the yoke body
13.
At this time, the deformable bands
14d of the auxiliary yoke
14
are arranged to face the engaging openings
13d of the yoke body
13
and at least the central bridged portion
14d1 of each of the
deformable bands
14 is inserted or snapped into the corresponding engaging
openings
13d to prevent the auxiliary yoke
14 from rotating
and moving axially relative to the yoke body
13.
In this case, since the auxiliary yoke has an elasticity and the slit
14c,
even though the deformable bands are projected inwardly of the auxiliary yoke,
a scratch or the like does not occur on the yoke body.
Alternatively, when the deformable bands are faced the engaging openings,
when a worker presses the deformable bands to insert them into the engaging openings,
the deformable bands, especially the central bridged portions are deformed to insert
into the engaging openings. At this time, the inclined surfaces are also pressed
against the edges of the engaging openings. As a result, the auxiliary yoke
14
is locked certainly on the yoke body
13. In this embodiment, it is not necessary
that the auxiliary yoke
14 has the aforementioned structure for enlarging
peripherally. In addition, since the deformable bands are not projected inwardly
of the auxiliary yoke at an initial step, even though the auxiliary yoke is rotated
on the yoke body, a scratch or the like does not occur on the yoke body.
In the aforementioned first embodiment, because the electric motor
10
has
the four inclined surfaces
14d3, these four inclined surfaces
in each deformable band
14d are pressed on the edges of each of the
engaging openings
13d.
More specifically, as shown in FIG. 7, the upper two inclined surfaces
14d3
in each deformable opening
14d are pressed upward and rightward and
leftward as shown by the arrows in FIG. 7 on the upper edge of the engaging opening
13d, and the lower two inclined surfaces
14d3
are pressed downward and rightward and leftward as shown by the arrows in FIG.
7 on the lower edge of the engaging opening
13d.
In this way, because the four inclined surfaces
14d3 in
each
deformable band
14 are adapted to impart a pressed force on the edges of
the engaging opening
13d in axial and peripheral directions of the
yoke body
13, the auxiliary yoke
14 is locked certainly on the yoke
body
13 without being moved relative to the yoke body. This is accomplished
by only inserting each of the deformable bands
14d provided in the
auxiliary yoke
14 into each of the engaging openings
13d provided
in the yoke body
13 by rotating relatively the auxiliary yoke and yoke body.
In addition, when the auxiliary yoke
14 is locked on the yoke body
13,
and the electric motor
10 is attached through the mounting bracket
22
to the mounting object, even during driving of the electric motor, the yoke body
13 is not moved within the auxiliary yoke
14 to maintain a stability
of the assembled electric motor.
In the aforementioned electric motor, when the stoppers
14f are
contacted with the protrusions
13f, the deformable bands
14d
are faced to the engaging openings
13d and therefore it is very
easy to fit the deformable bands in the engaging openings.
Referring to FIG. 15, a second embodiment of the present invention is shown.
In the second embodiment, the similar numerals are attached to the similar parts
as in the first embodiment.
In the embodiment, a configuration of each of deformable bands
114d
is shown in FIG. 15. In the configuration, the deformable band
114d
is formed between an upper elongate rectangular cutout S
1 and a lower
trapezoidal cutout S
2 as shown in FIG. 15. As a result of the cutouts, the
deformable band
114d has a lower part having the inclined surfaces
14d3 and
14d3 similar to that in the
first embodiment, which are symmetrical in right and left, as viewed from FIG.
15, and an upper part formed from a straight surface
115.
An arrangement and so on of the deformable bands
114d are the same
as that in the deformable bands
14d in the first embodiment.
When the deformable bands
114d are inserted into the engaging
openings
13d, the auxiliary yoke
14 is no moved relative to
the yoke body
13. Further, the edges of the engaging openings
13d
are pressed downward and rightward and leftward as shown by arrows in FIG.
15 by means of the inclined surfaces
14d to prevent the auxiliary
yoke
14 from moving peripherally thereby locking further certainly the axial
and peripheral movements of the auxiliary yoke
14 relative to the yoke body
13.
More specifically, when the inclined surfaces
14d impart downwardly
a pressed force to the edges of the engaging openings, there is a possibility that
an energized force is imparted to the auxiliary yoke
14, which tends to
move upwardly (as viewed in FIG. 15) the yoke body
13.
However, at this time, the stoppers
14f of the auxiliary yoke
14 are abutted with the lower end of the yoke body
13 and therefore
the auxiliary yoke
14 does not move upwardly relative to the yoke body.
In the electric motor in the embodiment, the auxiliary yoke
14 is locked
certainly to the yoke body
13 only by inserting the deformable bands
114d
of the auxiliary yoke
14 into the engaging openings
13d of
the yoke body
13.
Referring to FIG. 16, a third embodiment of the present invention is shown.
In FIG. 16, the similar numerals are attached to the similar parts as in the
first
and second embodiments.
In the embodiment, the electric motor
10 has deformable bands
214d
each of which is formed between the same upper elongate rectangular cutout
S
1 as in the second embodiment and a lower cutout S
3, as shown in
FIG. 16. The lower cutout S
3 has a right straight surface and a left inclined
surface as viewed in FIG. 16. As a result of the cutouts, each deformable band
214d has a lower part having an inclined surface
214d3
and a straight surface
216 and an upper part formed from a straight surface
215.
An arrangement and the other structure of the deformable bands
214d
are the same as that in the deformable bands
14d and
114d
in the first and second embodiments.
When the deformable bands
214d are inserted into the engaging
openings
13d, the auxiliary yoke
14 is no moved relative to
the yoke body
13. Further, the edges of the engaging openings
13d
are pressed downward and leftward as shown by arrows in FIG. 16 by means of
the inclined surfaces
214d3 to prevent the auxiliary yoke
14 from moving peripherally thereby locking further certainly the axial
and peripheral movements of the auxiliary yoke
14 relative to the yoke body
13.
The other operation of the deformable bands
214d is the same as
in the second embodiment.
In the electric motor in the embodiment, the auxiliary yoke
14 is locked
certainly to the yoke body
13 only by inserting the deformable bands
214d
of the auxiliary yoke
14 into the engaging openings
13d of
the yoke body
13.
As described above, according to the present invention, it is possible to prevent
the auxiliary yoke from removing relative to the yoke body by means of a easy operation.
Although the various embodiments have been explained, the present invention
is not limited to these embodiments. For example, in the aforementioned embodiments,
two sets of the deformable bands and engaging openings have been provided on the
yoke, but, one set or three sets of the deformable bands and engaging openings
may be provided on the yoke.
A shape and a size of the deformable bands and engaging openings are also not
limited
to that in the above embodiments.
*
