JPH1182553A - Electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow simple mounting works for an armature on a hub and permit the armature to rotate integrally with the hub while a sufficient strength is secured. SOLUTION: A yoke assembly is structured so that an electromagnetic coil is installed at a cylindrical part of a bobbin in a yoke. A rotary shaft is inserted rotatably in the cylindrical part of the bobbin, and a rotor is fitted on the shaft in such a way as rotatable integrally with the shaft. A hub 40 is rotatably fitted on the shaft on its side opposite the electromagnetic coil with the rotor interposed. A cylindrical extension part 40b is provided at the opening edge of the center hole 40a in the hub 40 side face confronting the rotor. An armature 42 is fitted on the extension part 40b in the condition that it is in convex- concave fitting with the extension part 40b in such a way as not rotatable with respect to the hub 40 and movable in the longitudinal direction of the extension part 40b (by key 42b and key seat 46) and is energized toward the hub 40 at all times by a leaf spring 44 attached in engagement to the extension part 40b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic clutch, and more particularly to an electromagnetic clutch characterized by a structure for mounting an armature to a hub.

[0002]

2. Description of the Related Art A basic structure of a conventional electromagnetic clutch 100 will be described with reference to FIGS. 17, 18 and 19. FIG.
First, each component of the electromagnetic clutch 100 will be described in detail. The yoke 102 is made of a magnetic material (iron as an example) and is formed in a cylindrical shape with a bottom. A circular hole 104 is opened in the bottom 102a. The electromagnetic coil 106 includes a bobbin 108 formed using a synthetic resin material having electrical insulation, and an electric wire 110 wound around the outer peripheral surface of the cylindrical portion 108b of the bobbin 108. Here, the outer shape of the flange 108a formed at both ends of the cylindrical portion 108b is set to be an annular shape according to the cross-sectional shape of the inner peripheral surface of the yoke 102 so that the electromagnetic coil 106 can be mounted inside the cylindrical yoke 102. I have.

[0003] The sleeve 112 is made of a magnetic material (iron as an example).
The bobbin 108 is formed into a cylindrical shape having an outer diameter slightly smaller than the inner diameter of the cylindrical portion 108b. Sleeve 1
Numeral 12 is for fixing the electromagnetic coil 106 in the yoke 102 and forming a magnetic circuit of the electromagnetic coil 106. The mounting structure is such that the electromagnetic coil 106 is mounted on the yoke 102, and the sleeve 112 is attached to the bobbin 108. It is inserted into the cylindrical part 108b. Then, the insertion-side end of the sleeve 112 is connected to the rim or inner periphery of the circular hole 104 of the yoke 102 by means such as caulking, and the other end 112a whose diameter has been increased is connected to the flange 108 of the bobbin 108.
a. Thereby, the electromagnetic coil 106
Is held between the inner peripheral surface of the yoke 102 and the outer peripheral surface of the sleeve 112, and a yoke assembly including the yoke 102, the electromagnetic coil 106, and the sleeve 112 is completed. At the center of the yoke assembly, a circular hole coaxial with the tubular portion 108b of the bobbin 108 and located in the tubular portion 108b is formed by the inner peripheral surface of the sleeve 112.

The rotating shaft 114 has a cylindrical outer shape, and is formed using a magnetic material (for example, a metal material such as iron). Also, grooves 116 for retaining rings are provided on the outer peripheral surfaces of both ends along the circumferential direction. The outer diameter of the rotating shaft 114 is slightly smaller than the inner diameter of the sleeve 112 and is inserted into a circular hole formed at the center of the yoke assembly, that is, into the sleeve 112. An output shaft (not shown) is mounted in the rotation shaft 114. A flat surface provided on the output shaft is provided on the inner peripheral surface of the rotation shaft 114 so that the output shaft can rotate integrally with the rotation shaft 114. A D-cut portion 114a that fits into a portion (not shown) is formed.

The rotor 118 is formed in a ring shape using a magnetic material (for example, a metal material such as iron), and a rotary shaft 114 is inserted into a circular hole provided at the center.
Is fixed so as to be coaxial with the rotation shaft 114. As a fixing method, usually, the rotating shaft 114 is press-fitted into a circular hole of the rotor 118 and fixed. The fixed position of the rotor 118 on the rotation shaft 114 is
When the rotating shaft 114 to which the fixed shaft 18 is fixed is inserted into the sleeve 112, the rotor 118 comes to a position close to the end face of the electromagnetic coil 106, and a stopper ring formed at the insertion-side end of the rotating shaft 114. The groove 116 is set at a position protruding from the outer wall surface of the yoke 102. The hub 120 receives a rotational force from the outside, and is formed into a disk shape using a synthetic resin material as an example, and has teeth formed on an outer peripheral surface thereof. The hub 120 is a rotor 118
Is rotatably fitted on the outer peripheral surface of the rotating shaft 114 opposite to the electromagnetic coil 106 so as to be coaxial with the rotating shaft 114. As shown in FIG. 18, a cylindrical extension 120 b is formed at the edge of the circular hole 120 a provided at the center of the hub 120, through which the rotating shaft 114 is inserted, on the rotor 118 side. Has a structure in which a gap is formed between the hub 120 and the rotor 118 when is externally fitted to the rotating shaft 114.

[0006] The armature 122 is formed in a ring shape using a magnetic material. Then, it is externally fitted to the extending portion 120b, and is attached to the side surface of the hub 120 facing the rotor 118 so as to rotate integrally with the hub 120 using a leaf spring 124. The connection between the leaf spring 124 and the armature 122 is made integral by inserting a projection formed on the side surface of the armature 122 into a hole 124 a provided in the leaf spring 124 and then crushing the projection. That is, they are connected by caulking. Further, the structure in which the armature 122 having the leaf spring 124 integrally attached to the hub 120 is provided with a screw hole 124b in the leaf spring 124.
A cutout 122a is formed in the armature 122 on the inner peripheral surface of the armature 122 at a position corresponding to the screw hole 124b. The armature 12 is provided on the side surface of the hub 120 on the side of the extending portion 120b so that the leaf spring 124 is interposed between the armature 12 and the hub 120.
2 is fixed using screws 126. When an external force exceeding the elastic force of the leaf spring 124 acts on the armature 122 in a direction opposite to the hub 120, the leaf spring 124 is elastically deformed, and the armature 122 moves on the rotation shaft 114 toward the rotor 118 by a small distance. Only movable. When this external force stops acting, the armature 12
2 moves toward the hub 120 by the elastic force of the leaf spring 124 and returns to the original position. Further, since the armature 122 is connected to the hub 120 through the leaf spring 124, the armature 122 rotates integrally with the hub 120.

Next, the procedure for assembling the components will be described. First, the electromagnetic coil 106 is fixed using the sleeve 112 in the yoke 102 as described above. Subsequently, the first bearing 128 is fitted to one end of the rotating shaft 114 to which the rotor 118 is fixed, and then the rotating shaft 114 is inserted into the sleeve 112 from the one end of the rotating shaft 114. The one end on the insertion side of the rotating shaft 114 is the yoke 102.
, The second bearing 129 is externally fitted to the rotating shaft 114 from one end thereof, and is interposed between the sleeve 112 and the rotating shaft 114. Thereafter, the retaining ring 13 is inserted into the groove 116 formed on the one end side of the rotating shaft 114.
Insert 0. Accordingly, the retaining ring 130 is provided at the edge of the circular hole of the yoke assembly (the circular hole is formed by the inner peripheral surface of the sleeve 112, so that the retaining ring 130 is formed at the second edge).
And the rotation shaft 114 is prevented from coming off from the sleeve 112. In other words, the yoke assembly does not come off from the rotating shaft 114.

Subsequently, the hub 120 to which the armature 122 is attached as described above is fitted around the outer periphery of the other end of the rotating shaft 114 so that the armature 122 faces the rotor 118. Finally, a retaining ring 130 is fitted into a groove 116 formed on the outer periphery of the other end of the rotating shaft 114 protruding from the hub 120. Thereby, the hub 12
Of the circular hole 120a provided at the center of
30 is engaged with the hub 120 so that the hub 120 does not come off the rotating shaft 114. As a result, the sleeve 112, the yoke 102, the rotor 118, and the hub 120 are sandwiched by the pair of retaining rings 130 via the common rotary shaft 114 and are integrally assembled, and the electromagnetic clutch 100 having the structure shown in FIG.
Is completed. In this electromagnetic clutch 100, as described above, the first and second synthetic resin
Are arranged, and the rotating shaft 114 is inserted into the sleeve 112 via each bearing 128, so that smooth rotation with little friction is ensured.

Here, the shape of the first bearing 128 will be described. The first bearing 128 is formed of a synthetic resin material, and has a cylindrical portion 128b and a circular portion formed at one end of the cylindrical portion 128b. And a flange portion 128a. The outer diameter of the cylindrical body portion 128 b is slightly smaller than the inner diameter of the sleeve 112, and the inner diameter is slightly larger than the outer diameter of the rotating shaft 114. And this cylindrical part 1
28b is interposed between the inner peripheral surface of the sleeve 112 and the outer peripheral surface of the rotating shaft 114 to reduce friction between the sleeve 112 and the rotating shaft 114. In addition, in order to reduce the size of the electromagnetic clutch 100, the thickness of the bearing 128 is formed as thin as possible within a range where the strength can be secured. Also, the second bearing 129
Has the same configuration as the first bearing 128, and has a cylindrical body 129.
b and a flange portion 129a.

In the thus manufactured electromagnetic clutch, when the electromagnetic coil 106 is in a non-energized state, a gap is formed between the armature 122 and the rotor 118, and the rotational force input to the hub 120 is It is not transmitted to the rotor 118, so that the rotating shaft 114 and even the output shaft do not rotate. When the electromagnetic coil 106 is energized, a magnetic circuit as shown by a dotted line in FIG. 19 is formed in the yoke 102, the sleeve 112, the rotating shaft 114, the rotor 118, and the armature 122. For this reason, armature 12
2 moves to the rotor 118 side against the urging force of the leaf spring 124 and is attracted to the rotor 118. Therefore, the hub 120
Is input to the leaf spring 124 and the armature 1
22 to the rotor 118, and
14. Finally, it is transmitted to the output shaft. In addition,
When the electromagnetic coil 106 is de-energized again, the attractive force of the electromagnetic coil 106 to the armature 122 disappears, so that the armature 12
2 moves to the hub 120 side, and a gap is generated between the armature 122 and the rotor 118.

[0011]

However, the above-mentioned conventional electromagnetic clutch has the following problems. Since the armature 122 is screwed to the hub 120 via a leaf spring 124 connected to the armature 122 by caulking, the work of caulking the leaf spring 124 to the armature 122, the work of forming a screw hole to the hub 120, and the operation of the armature 12
2 requires screwing work to the hub 120, and in any process, there is a problem that processing and mounting work take time, and assembly of the electromagnetic clutch takes time. In particular, since the transmission of the rotational force from the hub 120 to the armature 122 is performed via the leaf spring 124, the strength of the leaf spring 124 itself needs to be secured, so that a cheap and inexpensive material cannot be used. Therefore, there is a high possibility that the unit cost of parts will increase. Further, the armature 122 and the leaf spring 24
Since a force is applied to each of the caulking portion and the screw-fastened portion to the hub 120, it is necessary to be careful in processing and assembling work, and there is a problem that the working time is further increased.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-mentioned problems, and an object of the present invention is to make it possible to easily mount an armature on a hub and to rotate the armature integrally with the hub with sufficient strength. It is to provide an electromagnetic clutch which can be used.

[0013]

In order to achieve the above-mentioned object, the invention according to claim 1 of the present invention comprises:
A yoke assembly in which an electromagnetic coil formed by winding an electric wire around the cylindrical portion of the bobbin is mounted, a rotating shaft rotatably inserted into the cylindrical portion of the bobbin, and a ring-shaped member formed of a magnetic material. A rotor rotatably fitted to the rotating shaft so as to be integrally rotatable with the rotating shaft, and a circular hole formed at the center, and rotatably mounted on the rotating shaft on a side opposite to the electromagnetic coil with the rotor interposed therebetween. An electromagnetic clutch comprising a fitted hub and a ring-shaped armature which is fitted around the rotating shaft and is attached to a side of the hub facing the rotor by using a leaf spring; A cylindrical extension that allows the rotation shaft to pass therethrough is formed at the edge of the center hole on the opposing side surface, and the armature cannot rotate with respect to the hub and extends in the longitudinal direction of the extension. A hub that can move freely along Or the outer surface is fitted to the extending portion in an unevenly fitted state with the extending portion, and is always urged toward the hub by a leaf spring that is fitted and attached to the extending portion. .

With this configuration, the armature can be attached to the hub without using screws, and the workability is improved. Further, since the armature is configured to be fitted into the hub in an uneven manner and rotate integrally with the hub, the armature can be attached to the hub with sufficient strength. In particular, since the rotational force is not applied to the leaf spring as in the related art, the connection strength between the armature and the hub is greatly increased. Further, the range of choice of the material of the leaf spring is expanded, and it is possible to manufacture the leaf spring at lower cost.

As a specific example of the concave-convex fitting, as an example, a large-diameter portion having a key groove formed on the outer peripheral surface is formed at the base of the extending portion, and the armature is provided with the key groove on the inner peripheral surface thereof. A configuration may be employed in which a key that fits with the outside diameter is formed and externally fitted to the enlarged diameter portion. In addition, the leaf spring is formed of a material having elasticity, the outer shape is formed in a ring shape that can be fitted to the extension portion, and an inner edge is formed with an inner edge protrusion that can be engaged with the extension portion. A configuration in which an outer edge projection that engages with the armature is formed on the outer edge so as to be separated from the inner edge projection along the circumferential direction can be adopted.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an electromagnetic clutch according to the present invention will be described below in detail with reference to the accompanying drawings. First, as shown in FIG. 1, the electromagnetic clutch 10 mainly includes a yoke assembly 15 including a yoke 12 and an electromagnetic coil 14, a rotating shaft 16, a rotor 18, and a hub assembly 20. The components will be described in detail.

(Yoke Structure) In the present embodiment, the yoke 12 is, for example, a first yoke body 22 formed by bending a magnetic material (for example, a metal plate) into a U-shaped cross section as shown in FIG. And a second yoke 2 which is formed using a magnetic material and is fitted between both ends of the pair of bent pieces of the first yoke 22.
And 4. The yoke 12 is formed as a whole in a rectangular shape in cross section by the configuration in which the first yoke body 22 and the second yoke body 24 are connected. And the first yoke body 2
2 has a first circular hole 2 through which a rotating shaft 16 is inserted.
2a is provided, and a second circular hole 24a in which the rotor 18 is fitted is provided in a central portion of the second yoke body 24. Further, as another embodiment of the yoke 12, the first
The yoke body 22 is formed in a bottomed cylindrical body, and the second yoke body 2
Reference numeral 4 may be formed in a disc so as to close the opening of the first yoke body 22. Further, the inner diameter of the opening portion of the first yoke body 22 is formed to be slightly larger than the outer diameter of the rotor 18, and the second yoke body 24 is structured such that the rotor 18 directly fits into the opening portion of the first yoke body 22. It may be omitted. The structure of the latter yoke is the same as the structure of the yoke 102 described in the conventional example.

The first yoke body 22 and the second yoke body 24 are connected by fitting recesses 22b at both end edges of the first yoke body 22.
On the other hand, fitting protrusions 24b to be fitted into the fitting recesses 22b are formed on both end edges of the second yoke body 24 which are in contact with the first yoke body 22. Then, after the fitting projection 24b is fitted into the fitting recess 22b, the fitting projection 24b is fixed in the fitting recess 22b by caulking.

(Electromagnetic Coil, In particular, Structure of Bobbin) The electromagnetic coil 14 has a bobbin 26 formed of a synthetic resin material having electrical insulation properties and having a structure shown in FIGS. And an electric wire 28 wound around the outer peripheral surface of the shape portion 26a. The shape of the flanges 26b and 26c formed at both ends of the bobbin 26 is set so that the bobbin 26 can be mounted inside the yoke 12.
26c is set according to the inner surface shape of the yoke 12 with which it contacts. Specifically, at least the second yoke body 24
The shape of the flange 26b in contact with the inner surface of FIG.
As shown in FIG. 2, both end edges that come into contact with the tip of the first yoke body 22 are formed by straight lines parallel to each other, and the width A thereof is set to a length substantially matching the distance between the inner wall surfaces of both ends of the first yoke body 22. Is set. In addition, a pair of positioning pieces 26d that engage with both end edges of the second yoke body 24 where the fitting protrusions 24b are not formed are provided on the other end edges of the flange 26b so as to face each other. In the present embodiment, since both end edges of the second yoke body 24 are formed in an arc shape as an example,
The positioning piece 26d is also formed in an arc shape accordingly.

A first bearing 27 and a second bearing 29 are disposed at both ends of the sleeve 30 as in the conventional example, and the rotating shaft 16 is rotatably supported in the sleeve 30 by the bearings 27 and 29. In this embodiment, as shown in FIG. 3, the first bearing 27 disposed at the end of the sleeve 30 on the rotor 18 side is provided with a rotor 18 of the cylindrical portion 26a of the bobbin 26. The feature is that it is integrally connected to the side lip. The structure of each of the bearings 27 and 29 will be described with reference to FIGS. The first bearing 27 and the second bearing 29 arranged on the flange of the bobbin 26 of the sleeve 30 on the flange 26c side together with the bearing 12 described in the related art.
8, cylindrical portions 27b and 29b interposed between the inner peripheral surface of the sleeve 30 and the outer peripheral surface of the rotary shaft 16, and the cylindrical portions 27b and 29b. And flange portions 27a and 29a formed on one end side of the.

In this embodiment, each flange 27
Although a and 29a are formed in a circular shape according to the shape of the cylindrical portions 27b and 29b, they are not particularly limited to a circular shape, and may be an ellipse or a square. In particular, in the case of the first bearing 27, if the cylindrical portion 27b can be integrally connected to the bobbin 26 in a state where the cylindrical portion 27b is coaxially arranged in the cylindrical portion 26a of the bobbin 26, a flange-like shape is particularly preferable. It is not necessary to be limited to this. For example, a plurality of extending pieces radially extending in the radial direction may be used. The first bearing 27 has a flange portion 27a having a cylindrical portion 26.
a of the rotor 18 on the rotor 18 side.
The cylindrical body 27b is disposed coaxially within the cylindrical part 26a of the bobbin 26. The bobbin 26 and the first bearing 27 may be separately manufactured and integrally joined by means such as adhesion or welding. However, in practice, the bobbin 26 and the first bearing 27 are formed using a synthetic resin material. It is good to be integrally molded. Thus, the number of parts can be reduced, and the step of attaching the first bearing 27 can be omitted, so that the product cost can be reduced.

The end of the sleeve 30 on the rotor side is the inner peripheral surface of the cylindrical portion 26a of the bobbin 26, the flange portion 27a of the first bearing 27, and the cylindrical portion 27b shown in FIG.
The cylindrical body portion 27 b of the first bearing 27 is disposed in close contact with the inner peripheral surface of the sleeve 30. Also, as shown in FIG.
A second bearing 29 is disposed at an end opposite to the end of the sleeve 30 with its flange portion 29a in contact with the end surface of the sleeve 30.
The cylindrical portion 29b of the second bearing 29 is disposed in close contact with the inner peripheral surface of the end of the sleeve 30. Therefore, bobbin 26
The rotary shaft 16 inserted into the cylindrical portion 26a of the
Within 0, it is rotatably supported by the cylindrical portion 27b of the first bearing 27 and the cylindrical portion 29b of the second bearing 29. In the present embodiment, the rim of the cylindrical portion 26a to which the first bearing 27 is coupled on the rotor 18 side is shown in FIG.
As shown in (c), it is formed so as to protrude toward the rotor 18 from the side surface of the flange 26b. Accordingly, the rotor 18 only comes into contact with the end surface of the cylindrical portion 26a of the bobbin 26 on the rotor 18 side and the side surface of the flange portion 27a of the bearing 27, and does not entirely contact the side surface of the flange 26b of the bobbin 26. The contact area is small and smooth rotation with little friction can be performed. Although the number of parts and the number of mounting steps increase, the first bearing 27 is the first bearing 12 described in the conventional example.
As in the case of 8, it may be of a shape separated from the bobbin 26.

(Sleeve Structure) The sleeve 30 is formed in a cylindrical shape using a magnetic material. One end is connected to the first yoke body 22 at right angles to the first circular hole 22a by means of press fitting or caulking. Further, since the sleeve 30 is inserted into the tubular portion 26a of the bobbin 26, the outer diameter is formed to be slightly smaller than the inner diameter of the tubular portion 26a. Further, the inner diameter of the sleeve 30 is such that the rotating shaft 16 inserted into the cylindrical portion 26 a of the bobbin 26 defines the cylindrical portion 27 b of the first bearing 27 and the cylindrical portion 29 b of the second bearing 29 in the sleeve 30. Since it is inserted through the rotary shaft 16, the diameter is slightly larger than the sum of the outer diameter of the rotating shaft 16 and twice the thickness of the cylindrical body 27b or the cylindrical body 29b.
The function of the sleeve 30 lies in the holding of the electromagnetic coil 14 and the configuration of the magnetic circuit as described in the conventional example. When the first bearing 27 is separated from the bobbin 26 similarly to the first bearing 128 of the conventional example as described above, the sleeve 30 has the same configuration as the sleeve 112 of the conventional example.
The bobbin 26 may be prevented from falling out of the first yoke body 22 at the other end 112a having the increased diameter.

(Structure of Rotating Shaft) As shown in FIG. 4, the rotating shaft 16 has a cylindrical outer shape as a whole, and is constituted by a circular hole 15a of the yoke assembly 15, specifically, an inner peripheral surface of the sleeve 30. Rotatably inserted into the circular hole. Further, the rotor 18 and the hub assembly 20 are externally fitted to the rotating shaft 16. Conventionally, as described above, it is formed using only a metal material such as iron, which is a magnetic material. However, in the present embodiment, as shown in FIGS. 4 and 5, a cylindrical second material made of a synthetic resin material is used. It comprises a rotating shaft 32 and a cylindrical first rotating shaft 34 which is fitted externally to the second rotating shaft 32.

The structure of each rotating shaft 32, 34 will be described in detail. First, the longer second rotary shaft body 32 is formed into a cylindrical body as shown in FIG. 6 using a synthetic resin material, and a hook portion 36 is formed at one end and the other end is formed. A groove 38 for a retaining ring is provided on the outer peripheral surface of the portion. An insertion hole 32b is formed at the center of the second rotating shaft body 32, and an output shaft (not shown) in which transmission and non-transmission control of the rotational force is performed by an electromagnetic clutch is formed in the insertion hole 32b. The rotary shaft 32 is inserted and inserted from one end side.
Similarly to the conventional rotary shaft 114, the output shaft is provided on the inner peripheral surface of the end of the second rotary shaft 32 on the yoke 12 side so that the output shaft can rotate integrally with the second rotary shaft 32. A D-cut portion 32a that fits with a flat portion (not shown) formed on the outer peripheral surface is formed. Since the D-cut portion 32a is formed at the end of the second rotary shaft 32 opposite to the end where the output shaft is inserted, the output shaft is inserted from the end of the second rotary shaft 32 on the yoke 12 side. If so, it is formed at the end on the hub 40 side. Further, in the present embodiment, the insertion hole 32b is formed as a hole penetrating the second rotary shaft 32, but is formed as a hole opened only at one end side of the second rotary shaft 32, and a D-cut portion is formed. 32a may be formed at the back of the insertion hole 32b. The length of the second rotary shaft body 32 is set to a length extending between the yoke assembly 15 and the hub assembly 20 (specifically, a hub) as shown in FIG.

A plurality of hook portions 36 are provided on one outer peripheral surface of one end of the second rotating shaft 32 along the longitudinal direction of the second rotating shaft 32 (for example, two at line-symmetric positions). It is formed in the shape of a tongue extending toward the end. The yoke assembly 15 is provided on the outer surface of the tip of the hook 36.
Is formed with an engaging projection 37 which engages with the edge of the circular hole 15a formed at the center of. The tip of the hook portion 36 is elastically deformable in the radial direction of the rotating shaft 16 as shown by the arrow in FIG. As the shape of the engagement projection 37, various shapes such as a rectangular shape and a semicircle can be adopted as long as the shape can engage with the edge of the circular hole 15a of the yoke assembly 15.
In the present embodiment, the distal end surface of the engaging projection 37 in the extending direction is formed as a tapered surface 37a that is narrowed down toward the extending direction of the hook portion 36. In the present embodiment, as shown in FIG. 1B, the end surface of the tip of the hook portion 36 is also formed into a tapered surface so as to be continuous with the tapered surface 37a of the engaging projection 37. As shown in FIG. 1 (c), at least only the distal end face of the engaging projection 37 in the extending direction that directly abuts on the edge of the circular hole 15a has a tapered surface 37a.
What is necessary is just to be formed. Also, the back surface of the tapered surface 37a of the engagement projection 37 is the circular hole 15a of the yoke assembly 15.
Is formed on the engaging surface 37b which engages with the rim of the rim. The engagement surface 37b is a surface that rises substantially perpendicularly from the outer surface of the hook portion 36, and can reliably engage with the edge of the circular hole 15a. Further, as an example, the hook portion 36 of the present embodiment once erects in the radial direction from the outer peripheral surface of the second rotary shaft 32 and then extends in parallel along the outer peripheral surface of the second rotary shaft 32, It reaches the end face of the second rotating shaft 32.

Next, as for the shorter first rotating shaft body 34, as shown in FIG.
Shorter and the cylindrical portion 26 of the sleeve 30 or bobbin 26
It is formed in a cylindrical body longer than a. The outer diameter of the first rotary shaft 34 is slightly smaller than the inner diameter of the cylindrical portion 27b of the first bearing 27 and the cylindrical portion 29b of the second bearing 29. The second rotary shaft 32 is inserted into the sleeve 30 together with the second rotary shaft 32 in a state of being formed to have a slightly larger diameter than the outer diameter of the second rotary shaft 32. When inserted into the cylindrical portion 26a of the bobbin 26, the first rotating shaft 34 is moved to the bobbin 26 as shown in FIG.
A part of the magnetic circuit between the edge of the first circular hole 22a of the first yoke body 22 and the rotor 18 as shown by a dotted line together with the sleeve 30 as shown in FIG. Is configured.

At one end of the first rotating shaft body 34, first notches 34 a into which hook portions 36 provided on the second rotating shaft body 32 are fitted are provided at the positions corresponding to the hook portions 36. , Are formed along the longitudinal direction of the first rotating shaft body 34. Also, the other end has the same number of second notches 34b as the arc-shaped projections (two as an example in the present embodiment) into which arc-shaped projections formed on the inner peripheral surface of the rotor to be described later are fitted. It is formed along the longitudinal direction of the body 34. Then, the second rotating shaft body 32 is arranged from the end side where the groove 38 is provided.
The hook 36 is inserted into the first rotary shaft 34 from the end side of the first rotary shaft 34 in which the first notch 34a is formed.
Press it in until it fits in the notch 34a. As a result, the first rotating shaft body 34 is integrally fitted to the second rotating shaft body 32 in a state where the first rotating shaft body 34 cannot rotate with respect to the second rotating shaft body 32, and the rotating shaft 16 is assembled. Further, as a method of forming the first rotary shaft body 34 so as to be integrally fitted to the second rotary shaft body 32, a method of integrally molding by insert molding may be adopted other than the method of press fitting described above.

When the rotary shaft 16 is inserted into the electromagnetic coil 12, the first rotary shaft body 34 forms the magnetic circuit of the electromagnetic coil 12 together with the sleeve 30 as described above. It has the function of increasing the number. In the conventional example, the entire rotating shaft is formed using a magnetic material. However, by appropriately setting the thickness of the first rotating shaft 34, the rotating shaft 16 can be connected to the second rotating shaft 32 made of synthetic resin. , A suction force to the armature 42 substantially equal to that of the conventional example can be secured. In the present embodiment, since the rotating shaft 16 has such a double structure, it is necessary to form the D cut portion 32a and the hook portion 36 while securing a sufficient suction force by the first rotating shaft body 34 of the outer layer. The second rotating shaft body 32 of the inner layer, which has a complicated shape due to the
In addition, it can be manufactured at low cost, and the unit cost of the entire rotating shaft 16 and further the entire electromagnetic clutch 10 can be reduced. If the rotary shaft 16 can be manufactured at low cost, the whole structure is made of a magnetic material like the rotary shaft 114 described in the conventional example instead of the above-described double structure of the metal material and the synthetic resin material. It may have a simple structure.

(Attaching Structure of Rotor to Rotary Shaft) Rotor 1
As shown in FIG. 4, reference numeral 8 denotes a ring formed of a magnetic material, which is fitted around the rotating shaft 16 so as to be coaxial with the rotating shaft 16, and rotates integrally with the rotating shaft 16. .
In the rotor 18 of the present embodiment, the inner diameter of the third circular hole 18a into which the rotating shaft 16 is inserted is formed to be slightly larger than the outer diameter of the first rotating shaft body 34, and further, the inner circumferential surface has an inner diameter. Second
A plurality of (two in the present embodiment, for example, two at point-symmetric positions) arc-shaped protrusions 18b formed slightly larger than the outer diameter of the rotating shaft body 32 are formed along the longitudinal direction of the rotor 18. .

The arc-shaped projection 18b is formed by the third
The rotating shaft 16 is inserted into the circular hole 18a, and the rotor 18 is moved in the direction of the first rotating shaft body 34 while sliding on the outer peripheral surface of the second rotating shaft body 38. After the contact, the rotor 18 can be easily fitted into the second cutout portion 34b by rotating the rotor 18 relatively to the rotating shaft 16, whereby free rotation of the rotor 18 with respect to the rotating shaft 16 is restricted, The rotor 18 can rotate integrally with the rotating shaft 16. Note that the shape of the arc-shaped projection 18b of the rotor 18 is set so as to minimize the backlash in the circumferential direction after being fitted to the rotating shaft 16. Further, the rotor 18 comes into contact with the first rotating shaft body 34 by fitting the arc-shaped projection 18b into the second notch portion 34b, so that the rotating shaft 16
Along the longitudinal direction is performed. In this way, the rotor assembly 17 is completed. However, when the rotating shaft 16 is entirely made of a magnetic material as in the conventional example, the rotor 18 is press-fitted into the rotating shaft 16 as in the conventional example. You may make it fix to.

(Structure of Hub Assembly) As shown in FIG. 8, the hub assembly 20 has a hub 40, an armature 4
2. It is composed of a leaf spring 44. Here, the hub 40 is formed in a disc shape using a synthetic resin material as an example, and rotates on the outer peripheral surface of the rotating shaft 16 on the opposite side of the electromagnetic coil 14 with the rotor 18 interposed therebetween so as to be coaxial with the rotating shaft 16. It fits freely on the outside. Also, a rotating shaft 1 provided at the center of the hub 40
A cylindrical extending portion 40b is formed at the edge of the fourth circular hole 40a as the circular hole through which the second member 6 is inserted, on the rotor 18 side.
When the hub 40 is fitted on the rotary shaft 16, a gap is formed between the hub 40 and the rotor 18, and the armature 42 and the leaf spring 44 are fitted on the extension 40 b in the gap. Be placed.

Next, each component of the hub assembly 20 will be described in detail. The present embodiment has a feature in the mounting structure of the armature 42 to the hub 40, and the features will be described below. At the base of the extension 40b of the hub 40, as shown in FIGS. 8 and 9, a key groove 46 for connecting the armature 42 to the outer peripheral surface is formed along the longitudinal direction of the extension 40b. 48 are formed.
In the present embodiment, three key grooves 46 are formed at equal angular intervals as an example, but two or more key grooves may be used. Further, the length of the enlarged diameter portion 48 is set so that the engagement relationship between the key groove 46 and the armature 42 is not released even when the armature 42 moves toward the rotor 18 along the longitudinal direction of the rotating shaft 16 by the electromagnetic coil 14. Is set.

Further, as shown in FIGS. 9 and 10, a mounting groove 50 for mounting a leaf spring 44 is provided on the outer peripheral surface of the extension portion 40b between the tip of the extension portion 40b and the enlarged diameter portion 48. Is formed. A guide groove 52 extending from the distal end to the mounting groove 50 is provided on the outer periphery between the distal end of the extending portion 40b and the mounting groove 50.
Are formed corresponding to inner edge projections of a leaf spring 44 described later. The width of the mounting groove 50 is formed slightly wider in accordance with the thickness of the leaf spring 44. Further, the opposing surface 52a of the guide groove 52 is formed on an inclined surface that is gradually separated toward the mounting groove 50. In the present embodiment, two guide grooves 52 are formed at point-symmetrical positions with respect to the axis of the extending portion 40b as a center, but a plurality of guide grooves such as three may be used.

The armature 42 is formed in a ring shape using a magnetic material, and has a central portion as shown in FIG.
A fifth circular hole 42a into which b is inserted is formed. More specifically, as shown in FIG.
a is divided along the axial direction into a large-diameter region C having a large inner diameter and a small-diameter region D having a smaller diameter than the large-diameter region. Here, the large diameter region C is located on the contact surface side of the armature 42 with the rotor 18, and a ring-shaped leaf spring 44 is mounted in the large diameter region C. Also, on the inner peripheral surface of the small-diameter region D of the fifth circular hole 42a, the same number of keys 42b as the key grooves 46 are fitted to the key grooves 46 formed in the extension portion 40b.
It is formed along the axial direction of a. Here, key 4
The length of the small-diameter region D in which 2b is formed is formed to be slightly longer than the length of the enlarged-diameter portion 48 of the extension portion 40b. With this configuration, when the armature 42 is externally fitted to the enlarged diameter portion 48 of the extension portion 40b, the armature 42 is non-rotatably attached to the hub 40 by the concave and convex fit between the key 42b and the key groove 46. The key 42b and the key groove 46 are movable along the longitudinal direction of the extending portion 40b while being integrally rotated with the hub 40. Further, the structure of the concave and convex fitting between the armature 42 and the hub 40 is not limited to the above-described spline structure formed by the key 42b and the key groove 46. For example, as shown in FIG. Also, the key 42b is not provided on the inner periphery of the small diameter region D of the armature 42, and the inside diameter of the small diameter region D is set so as to fit into the enlarged diameter portion 48. The armature 42 and the hub 40 may be configured such that concave and convex fit between opposing side surfaces thereof. As an example, a plurality of convex portions (for example, a columnar shape) 42 c are provided on the side surface of the armature 42, and the projections 4 are provided on the side surface of the hub 40.
A concave portion into which 2c can be inserted (a concave portion having a circular cross section as an example) 4
A structure in which a plurality of 0c are provided can be employed.

The ring-shaped leaf spring 44 is formed by punching or the like from a thin metal plate having elasticity. As described above, the plate thickness is set to a thickness that just enters the mounting groove 50. To explain the shape,
The leaf spring 44 has an outer diameter smaller than the inner diameter of the distal end of the arc-shaped key 42b formed on the inner peripheral surface of the small diameter region D of the armature 42, and the inner diameter is slightly larger than the outer diameter of the distal end of the extension 40b. It has a ring shape with a diameter. In addition, leaf spring 4
At the outer edge of the arc-shaped outer edge 4, when the leaf spring 44 is mounted in the large-diameter region C of the armature 42, it contacts the end surface of the small-diameter region D of the fifth circular hole 42 a and presses the armature 42 toward the hub 40. For example, two 44 a are formed at point-symmetric positions with respect to the center of the leaf spring 44. The diameter of the outer edge of the outer edge projection 44a is the fifth of the armature 42.
The diameter of the circular hole 42a is slightly smaller than the inner diameter of the large diameter region C.

An extension 40 is provided on the inner edge of the leaf spring 44.
The guide groove 52 is formed in the same number as the guide groove 52 corresponding to the position of the guide groove 52 provided at the front end of the guide groove 52b. An inwardly protruding inner edge projection 44b is formed.
The leaf spring 44 fixes the armature 42 to the extending portion 40b by being externally fitted to the extending portion 40b while the inner edge projection 44b is fitted in the mounting groove 50.

As described above, the leaf spring 44 has a function of attaching the armature 42 to the extending portion 40b of the hub 40 and a function as an urging means for always urging the armature 42 toward the hub 40 after the attachment. I have. Explaining the function as the urging means, the leaf spring 44 has an inner edge projection 44b formed on the inner edge thereof fitted into the mounting groove 50 of the extension portion 40b. 40b
Is larger than the outer diameter of The outer edge projection 44a is in contact with the end surface of the small diameter region D of the armature 42, but the outer diameter of the leaf spring 44 is the key 4 formed on the inner surface of the small diameter region D.
The diameter is smaller than the tip inner diameter of 2b. With this configuration, the leaf spring 44 has the inner edge projection 44b as a fulcrum, and the outer edge projection 44a formed on the outer edge of the leaf spring 44 urges the armature 42 toward the hub 40. Then, the ring-shaped body portion between the inner edge projection 44b and the outer edge projection 44a of the leaf spring 44 acts as a spring. For this reason, for example, the inner edge projection 4 serving as a fulcrum
4b, the distance from the inner edge projection 44b of the main body portion acting as a spring to the outer edge projection 44a is desirably equal, and by setting the distance equally, the armature 42 is attracted by the electromagnetic coil 14 and the rotor When the armature 42 is moved in the 18 directions, the armature 42 can be pressed uniformly without twisting the outer edge projection 44a.

In this embodiment, the number of the inner edge projections 44b and the number of the outer edge projections 44a are each two. For this reason, the inner edge projection 44b and the outer edge projection 44a are
Are provided at positions symmetrical with respect to the center, and the outer edge projections 44a are arranged at 90 degrees with respect to the inner edge projections 44b, so that the distance from the inner edge projections 44b to the outer edge projections 44a is equalized. Further, the armature 42 and the hub 40 are configured to be integrally rotated by engaging and recessing in the rotation direction as described above, and the torque of the hub 40 is directly transmitted to the armature 42 without the intermediary of the leaf spring 44. If the main purpose is to attach the leaf spring 44 to the armature 42 as in the conventional example, and attach the armature 42 to the hub 40 via the leaf spring 44 as in the conventional example.
It is also possible to adopt a structure for fixing to the head. Further, although the leaf spring 44 is configured using an elastic metal material, it may be formed of a rigid and elastic synthetic resin material.

Next, the procedure for assembling the components will be described. (Hub Assembly) First, a procedure for attaching the armature 42 to the hub 40 using the leaf spring 44 will be described with reference to FIG. The extending portion 40b of the hub 40 is inserted into the fifth circular hole 42a of the armature 42, and the armature 4
The key 42b is fitted into the key groove 46 while rotating the hub 2 and the hub 40 relatively. The armature 42 allows the extension 40b of the hub 40 to pass through with the small-diameter region D side of the fifth circular hole 42a facing the hub 40 side. Subsequently, the ring-shaped leaf spring 44 is fitted to the extension 40b with the inner edge projection 44b aligned with the position of the guide groove 52. In this state, the leaf spring 44 is mounted in the large diameter area C of the fifth circular hole 42a, and the outer edge projection 44a is in contact with the end surface of the small diameter area D of the fifth circular hole 42a.

Then, from this state, the leaf spring 44 is rotated in the circumferential direction. Then, since the facing surface 52a of the guide groove 52 is formed on the slope as described above, the inner edge projection 44b
Enters the mounting groove 50 along the facing surface 52a. The outer edge projection 44a also moves in the circumferential direction, and a part of the outer edge projection 44a comes into contact with the side surface of the key 42b protruding from the inner surface of the small diameter region D of the fifth circular hole 42a. During this rotation, the leaf spring 44
The position of the outer edge projection 44a in the axial direction of the extending portion 40b of the outer edge projection 44a remains unchanged in contact with the end face of the small-diameter region D, but the inner edge projection 44b is extended when the extension portion 40b is fitted into the mounting groove 50.
Move in the direction of the hub 40 along the axial direction of. Therefore, the ring-shaped main body portion between the inner edge projection 44b and the outer edge projection 44a of the leaf spring 44 is elastically deformed. Therefore, the leaf spring 44 is provided with the outer edge projection 44a based on the inner edge projection 44b.
An urging force for urging in the zero direction is generated. And
Armature 4 whose suction by electromagnetic coil 14 has been released
2 can be quickly returned to the original position by the urging force of the leaf spring 44. In addition, the inner edge protrusion 44
The frictional force between b and the mounting groove 50 also increases, and the leaf spring 44 is less likely to rotate, so that the mounting state of the armature 42 to the hub 40 can be maintained. Thus, the hub assembly 20 is completed. FIG. 15 shows a state where the hub assembly 20 is viewed from the leaf spring 44 direction. As can be seen from FIG. 15, the inner edge projection 44b of the leaf spring 44 enters the mounting groove 50 and engages with the extension 40b,
The outer edge projection 44a comes into contact with the end surface (side surface of the key 42b) of the small diameter region D of the armature 42, and the leaf spring 44 urges the armature 42 toward the hub 40 while the extension portion 40b
Is attached so that it cannot be removed.

(Yoke Assembly) Next, the yoke 12
And an yoke assembly 15
Will be described with reference to FIG. First, the sleeve 30 is mounted in the first yoke body 22 having a U-shaped cross section. One end of the sleeve 30 is inserted into the first circular hole 22a, and is fixed by caulking, press fitting, or the like so as to be coaxial with the first circular hole 22a. Secondly, the electromagnetic coil 14 is mounted on the first yoke body 22 while inserting the sleeve 30 into the cylindrical portion 26a of the bobbin 26. In the mounted state, one of the flanges 26 in the insertion direction of the bobbin 26 is
c is in close contact with the inner surface of the first yoke body 22, and
The distal end portion of the sleeve 30 inserted in a is housed in a ring-shaped space 31 formed in the other flange 26b.

Third, the second yoke body 24 is connected to the first yoke body 22, and the electromagnetic coil 14 is sandwiched and fixed between the first yoke body 22 and the second yoke body 24. As described above, the connection between the first yoke member 22 and the second yoke member 24 is performed by fitting the fitting protrusion 24b of the second yoke member 24 into the fitting recess 22b of the first yoke member 22, By narrowing the opening width, the fitting projection 24b is crimped and fixed. When connecting the first yoke member 22 and the second yoke member 24, first, the second yoke member 24 is placed on the other flange 26b of the bobbin 26. 26d is formed, and since the positioning pieces 26d are engaged with both lateral edges of the second yoke member 24, the second yoke member 24 does not shift.
Thus, the yoke assembly 15 is completed.

Next, a procedure for assembling the yoke assembly 15, the rotor assembly 17, and the hub assembly 20 integrally will be described with reference to FIG. First, the second bearing 29 is attached to its cylindrical portion 29.
b is inserted into the sleeve 30 from the end of the sleeve 30 on the first yoke body 22 side, and the flange portion 29a is
To the edge of the end. Second, the rotation shaft 16 of the rotor assembly 17 is inserted into the sleeve 30 from the hook portion 36 side in the second yoke body 24 direction. On this occasion,
The tapered surface 37a of the engagement projection 37 comes into contact with the edge of the flange 27a of the first bearing 27 and receives an inward pressure to elastically deform the hook portion 36 so that the distal end moves inward. The diameter is reduced, and the rotating shaft 16 is inserted into the sleeve 30. When the hook portion 36 projects from the second bearing 29,
The hook 36 expands to its original position by its own elastic force,
The engagement surface 37b of the engagement protrusion 37 formed at the tip portion engages with the rim of the circular hole 15a of the yoke assembly 15, that is, the rim of the sleeve 30 via the flange portion of the second bearing 29. I do. This prevents the yoke assembly 15 from being pulled out of the rotation shaft 16 from the hook portion 36 direction. In this state, the rotating shaft 16 is provided between the outer peripheral surface of the first rotating shaft body 34 and the inner peripheral surface of the sleeve 30 so that the cylindrical body portion 27 b of the first bearing 27 and the cylindrical body portion of the second bearing 29. 29
b is inserted into the sleeve 30 in a state where it is interposed.
Therefore, the rotating shaft 16 can rotate smoothly with little friction.

The rotor 18 is housed in the second circular hole 24a of the second yoke body 24.
8 has a side surface on the side of the electromagnetic coil 14 as described above.
6 is not in contact with the entire side surface of the flange 26b, but in contact with only the side surface of the cylindrical portion 26a of the bobbin 26 and the flange portion 27a of the first bearing 27. Therefore,
Since the contact area is small as compared with the case where the contact area is in contact with the entire side surface of the flange 26b, the rotational friction is small, and smooth rotation can be ensured. Third, the hub assembly 20 is mounted on the second rotating shaft 32 of the rotating shaft 16. That is, the second
The rotary shaft body 32 is inserted into the fourth circular hole 40 of the hub 40 from the end side where the groove 38 is formed, and from the extension 40 b side of the hub 40.
a, and the groove 38 of the second rotating shaft 32 is projected from the opposite side of the fourth circular hole 40a. Fourth, finally, the retaining ring 54 is fitted into the groove 38 of the second rotating shaft 32, and the assembly of the electromagnetic clutch 10 is completed. Thus, as shown in FIG.
The hook 36 and the retaining ring 54 are integrally assembled with the rotor 5, the rotor 18 and the hub assembly 20 in a state of being in close contact with each other.

(Other Embodiments of Rotating Shaft) In the above-described embodiment, the groove 38 is formed in the second rotating shaft body 32 and assembled by using the retaining ring 54. As shown, the hook portion 3 of the second rotating shaft 32
The second hook portion 56 having the same structure as that of the sixth embodiment may be formed instead of the groove 38 so that the electromagnetic clutch 10 can be assembled without using the retaining ring 54 at all. In the present embodiment,
The first rotating shaft body 34 and the second rotating shaft body 32 made of a magnetic material are integrated by insert molding, but instead of the groove 38 of the second rotating shaft body 32 of the rotating shaft 16 shown in FIG. Two hooks 56 may be provided. The detailed configuration is such that a second hook portion 56 is formed on the end face of the second rotating shaft 32 so as to extend in a direction opposite to the hook portion 36. In FIG. 13, as an example, two are formed at point-symmetric positions with respect to the axis of the second rotating shaft body 32. In addition, a second engagement protrusion 57 having the same configuration as the engagement protrusion 37 is formed on the outer surface of the second hook portion 56. The end face of the second hook portion 56 in the extending direction of the second engaging projection 57 is also formed in a tapered surface 57a so that it can be easily inserted into the circular hole 40a of the hub 40. Is formed as an engagement surface 57b. Then, the end of the second rotary shaft 32 on the second hook portion 56 side is inserted into the fourth circular hole 40a of the hub 40 from the extending portion 40b side of the hub 40, and the second hook portion 56 is inserted into the fourth circular shape. When the second hook portion 56 is protruded from the opposite side of the hole 40a, the second hook portion 56 expands to its original position by its own elastic force, so that the engagement surface 57b of the second engagement protrusion 57 becomes the fourth circular hole 40a Engages with the lip.

Therefore, as shown in FIG.
With the yoke assembly 15, the rotor 18, and the hub assembly 20 being substantially in close contact with each other, the hook 36 and the second hook 56 are integrally assembled. In this case, assembling can be performed by one-touch only by inserting the second rotary shaft 32 into the fourth circular hole 40a of the hub 40, so that the retaining ring 54 is not required at all, so that the working efficiency of the assembling operation is reduced. This is significantly improved as compared with the case where the wheel 54 is used. In the above-described embodiment, at least one of the second rotary shafts 32 has the hook 3
6 or the second hook portion 56 is formed to stop the use of the retaining ring 54 so as to improve the workability. However, in the case where the retaining ring may be used to prevent the retaining ring 54 from coming off, the rotation shaft 16 of the rotating shaft 16 may be used similarly to the conventional example. The groove 38 for the retaining ring 54 may be formed without providing the hook 36 and the second hook 56 at both ends.

As described above, various preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and many modifications can be made without departing from the spirit of the invention. Of course.

[0049]

According to the electromagnetic clutch of the present invention, the armature can be attached to the hub without using screws, and the workability of the assembling operation is improved. Further, since the armature is configured to be fitted into the hub in an uneven manner and rotate integrally with the hub, the armature can be attached to the hub with sufficient strength. In particular, since the rotational force is not applied to the leaf spring as in the related art, the connection strength between the armature and the hub is greatly increased. Further, there is an effect that the range of choice of the material of the leaf spring is expanded, and the leaf spring can be manufactured at lower cost.

[Brief description of the drawings]

1A is a side sectional view showing the structure of an electromagnetic clutch according to the present invention, FIG. 1B is an enlarged view of a hook portion thereof,
(C) is an enlarged view of another embodiment of the hook portion.

FIG. 2 is an exploded perspective view showing a configuration of the yoke assembly of FIG.

FIG. 3 is an explanatory view showing the structure of the bobbin of FIG. 2;
(A) is a side sectional view, (b) is a front view, and (c) is an enlarged view showing a configuration of a cap portion.

FIG. 4 is an exploded perspective view showing a configuration of the rotor assembly of FIG. 1;

FIG. 5 is a perspective view of a main part of the rotating shaft as viewed from the hook part side in FIG. 4;

FIGS. 6A and 6B are explanatory views showing the configuration of a second rotary shaft constituting the rotary shaft of FIG. 4, wherein FIG. 6A is a front view as viewed from a hook portion side, FIG. c) is a rear view, and (d)
FIG. 4 is a view taken along the line XX of FIG.

FIGS. 7A and 7B are explanatory views showing the configuration of a first rotary shaft constituting the rotary shaft of FIG. 4; FIG. 7A is a front view, FIG. 7B is a partially cutaway side view, and FIG. is there.

FIG. 8 is an exploded perspective view showing a configuration of the hub assembly of FIG. 1;

FIG. 9 is an explanatory view showing the configuration of the hub in FIG. 8;
Is a front view as viewed from the direction of the extending portion of the hub, and (b) is a side sectional view.

FIG. 10 is an enlarged view of a main part showing a structure of a mounting groove and a guide groove formed at a distal end of an extension of the hub of FIG. 8;

11A and 11B are explanatory views showing the configuration of the armature shown in FIG. 8, wherein FIG. 11A is a front view as viewed from the small-diameter region side, and FIG. 11B is a side sectional view.

FIG. 12 is an exploded perspective view of the electromagnetic clutch of FIG.

13A and 13B are explanatory views showing the configuration of another embodiment of the rotating shaft, wherein FIG. 13A is a front view as viewed from the hook portion side, FIG. 13B is a partially cutaway side view, and FIG. 13C is a rear view. , (D) is the X of (b)
FIG.

14 is a side sectional view showing the structure of another embodiment of the electromagnetic clutch using the rotating shaft of FIG.

FIG. 15 is a front view of the hub assembly of FIG. 8 after assembly, as viewed from the leaf spring direction.

FIG. 16 is an exploded perspective view showing another embodiment of the hub assembly.

FIG. 17 is an exploded perspective view showing a configuration of an example of a conventional electromagnetic clutch.

18 is an exploded perspective view showing the configuration of the hub assembly of FIG.

19 is a side sectional view showing a structure after assembling the electromagnetic clutch of FIG. 17;

[Explanation of symbols]

 12 Yoke 14 Electromagnetic coil 15 Yoke assembly 16 Rotary shaft 18 Rotor 22 First yoke body 24 Second yoke body 26 Bobbin 26a Tubular part of bobbin 28 Electric wire 40 Hub 40a Fourth circular hole 40b Extension 42 Armature 42b Key 44 Leaf spring 46 keyway

Claims (3)

[Claims] 1. A yoke assembly in which an electromagnetic coil formed by winding an electric wire around a cylindrical portion of a bobbin is mounted in a yoke; a rotating shaft rotatably inserted into the cylindrical portion of the bobbin; A rotor which is formed in a ring shape using a body, and which is externally fitted to the rotating shaft so as to be rotatable integrally with the rotating shaft; and a circular hole is formed at the center, on the opposite side to the electromagnetic coil with the rotor interposed therebetween. An electromagnetic arm comprising: a hub rotatably fitted to the rotating shaft; and a ring-shaped armature fitted to the rotating shaft and attached to a side of the hub facing the rotor by using a leaf spring. In the clutch, a cylindrical extending portion through which the rotating shaft can be inserted is formed at an edge of the center hole on a side surface of the hub facing the rotor, and the armature cannot rotate with respect to the hub. And the length of the extension Along with being externally fitted to the extending portion in a state in which it is movably fitted along the direction with the hub or the extending portion,
An electromagnetic clutch, wherein the electromagnetic clutch is constantly urged toward the hub by a leaf spring which is engaged with and attached to the extension portion. 2. An enlarged diameter portion having a key groove formed on an outer peripheral surface at a base portion of the extension portion, and a key that fits with the key groove is formed on an inner peripheral surface of the armature. The electromagnetic clutch according to claim 1, wherein the external clutch is fitted to the extended portion so as to be fitted into the extended portion. 3. The leaf spring is formed of a material having elasticity, and is formed in a ring shape whose outer shape can be fitted to the extension.
An inner edge projection is formed on the inner edge so as to be engageable with the extending portion, and an outer edge projection engaging with the armature is formed on the outer edge so as to be separated from the inner edge projection along the circumferential direction. The electromagnetic clutch according to claim 1 or 2, wherein