JPS626128B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exciting device for an electromagnetic clutch.

FIG. 1 is a diagram showing an electromagnetic clutch according to the prior art known from Japanese Utility Model Application Publication No. 53-64948.

Shaft 1 of compressor 12, which is a rotating load
A hub 16 is fixed to the distal end of 4 via a rotation stopper such as a key. Disk portion 16 of this hub 16
A movable piece 20 is attached to a via a leaf spring 18. These hub 16, leaf spring 18, and movable piece 20 constitute an output rotating body 21.
An input rotary body 22 is supported by a bearing 24 and rotatably disposed on the output rotary body 21 with a certain gap therebetween. An excitation device 26 is disposed inside the outer periphery of the input rotating body 22, and the excitation device 26 is equipped with an annular excitation coil 30 surrounded by an annular yoke main member 28. Further, between the magnetic poles of the movable piece 20 and the input rotating body 22, intermittent spaces or ring-shaped magnetic shielding parts 32a and 3 made of a non-magnetic material are provided.
2b and 32c are provided.

Next, the structure of the electromagnetic clutch excitation device 26 will be described in more detail. Said annular yoke main member 28
are the outer flange 28a and the inner flange 28b.
It has a U-shaped ring shape in cross section and is formed integrally by pressing electromagnetic mild steel. Reference numeral 34 denotes a support member, which, as shown in the figure, consists of a cylindrical portion 34a, a mounting portion 34b, and a bent portion 34c, and is integrally molded from steel by cold or hot forging. In particular, when dimensional accuracy is required, cutting is performed as necessary. Note that the cylindrical portion 34
A bearing 24 is fitted into the outer periphery of a, and the bearing 24
The input rotating body 22 is supported via the input rotating body 22.

These two members, the yoke member 28 and the support member 34, are joined by a method such as press-fitting, caulking, brazing, welding, etc. to form a stator. In addition, in a separate step, an annular excitation coil 30 having a U-shaped cross section with an open outer circumferential surface and wound with a rectangular cross section around an annular bobbin 36 made of insulating resin is inserted into the U-shaped portion of the stator. Thereafter, a resin insulator 38 is injected between the annular yoke main member 28, the annular excitation coil 30, and the bobbin 36 to form an excitation device 26. Note that numerals 40a and 40b are external lead wires for supplying current to the annular excitation coil 30.

Here, as the annular excitation coil 30 moves relative to the bobbin 36 due to vibration or the like, the external leader wire 40
A plurality of protrusions 36b are integrally formed on the side surface 36a of the bobbin 36 in order to prevent wires a and 40b from breaking. Further, the bobbin 36 and the annular excitation coil 30 are completely covered with a resin insulator 38 to firmly fix them together. Furthermore, a groove 28d is formed on the outer circumferential surface of the inner flange 28b of the annular yoke main member 28 or on a part of the inner circumferential side of the outer flange 28a.
is installed. This groove 28d is also filled with a resin insulator 38 to protect against external forces such as vibrations.
Excitation coil 3 enclosed in the resin insulator 38
Prevents 0 from jumping out. Note that FIG. 1A shows the main magnetic circuit.

In the above prior art, the means for fixing the resin insulator 38 to the annular yoke main member 28 in the circumferential direction is as follows:
It depends only on the adhesive strength of the resin insulator 38.
Therefore, in order to obtain sufficient adhesive strength even under high temperature conditions, expensive special resins or resin insulators are used.
8, the surface of the main yoke member 28 must be degreased and other pre-treatments are required, which both have the disadvantage of contributing to increased costs.

Furthermore, even if sufficient adhesion strength is obtained, if a heat shock such as a cooling/heating cycle is applied, the resin insulator 38 itself will be subjected to stress caused by the difference in the coefficient of thermal expansion of each component. Eventually, cracks occur in the resin insulator 38, and the adhesion force to the annular yoke main member 28 is greatly reduced, and as described above, the external lead wire 40 of the annular excitation coil 30
There were disadvantages such as disconnection of the wires a and 40b, and moisture infiltration through the cracks, resulting in poor insulation between the excitation coil 30 and the annular yoke main member 28.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, an object of the present invention is to provide an exciting device for an electromagnetic clutch in which the resin connecting the bobbin and the annular exciting coil does not peel off due to vibration and is highly reliable.

According to the present invention, the above object is achieved by integrally forming a plurality of protrusions on the side surface of the side plate of the main member of the annular yoke on the annular excitation coil side by pressing, making the protrusions abut against the side surface of the bobbin, and attaching the bobbin in advance. This is achieved by providing a gap between the main member of the annular yoke and the side surface, and filling this gap with a resin insulator.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram showing an embodiment of an excitation device for an electromagnetic clutch according to the present invention. However, similar or identical components to those in FIG. 1 are indicated using the same reference numerals. In this embodiment shown in FIG.
Since the other components are exactly the same as the conventional example described above, explanation of this part will be omitted and only the excitation device 26 will be described.

As shown in FIG. 3, the annular yoke main member 28 is press-formed into an annular U-shaped cross section that integrally has an inner flange 28b and an outer flange 28a that protrude in the axial direction from the inside of the side plate portion 28c, as in the conventional example. has been done. Here, several protrusions 28e are integrally formed by press on the U-shaped side surface of the side plate portion 28c. Note that 28f is a take-out hole provided for passing the external lead wires 40a and 40b from the annular excitation coil 30 through a grommet. Also,
Returning to FIG. 2, 28d is a groove serving as a means for preventing the resinous insulator 38 from popping out, similar to the conventional example.

The support member 34 is exactly the same as that of the conventional example described above, and the support member 34 and the annular yoke main member 28 are joined by the same method as in the conventional example to form a stator. Thereafter, in a separate process using the same method as in the conventional example, the bobbin 36 is wound with a rectangular cross section around an annular bobbin 36 that has a U-shaped cross section with an open outer peripheral surface and is made of insulating resin (for example, nylon, Delrin, etc.). The annular excitation coil 30 is inserted into the U-shaped cross section of the annular yoke main member 28 on the side surface 36a of the bobbin 36.
and the protrusion 28e until they come into contact with each other. next,
A resin insulator 38 such as epoxy resin is injected into the remaining space in the U-shaped cross section of the annular yoke main member 28 to form the excitation device 26 of this embodiment.
complete.

Since the present embodiment has the above-described configuration, the resin insulator 38 sufficiently penetrates between the side plate portion 28c and the side surface 36a of the annular bobbin 36 by the protrusion 28e of the annular yoke main member 28. The bobbin 36 and the annular excitation coil 30 are completely covered with a resin insulator 38 and fixed firmly. The above is the same as the prior art, but at the same time, the part with the protrusion 28e has a hole 38 formed on the side of the resin insulator 38 so as to surround it.
a is formed. For this reason, the yoke main member 28
The protrusion 28e and the hole 38a of the resin insulator 38 serve as means for fixing each other in the circumferential direction. Therefore, even when used in an environment where large external forces such as vibrations are applied, the annular excitation coil 3
The resin insulator 38 containing 0 will not move in the circumferential direction and damage the annular excitation coil 30, thereby improving the reliability of the excitation device 26.

According to this embodiment, the resin insulator 38 is fixed to the annular yoke main member 28 in the circumferential direction by the protrusion 28e.
Since this is done mechanically through the hole 38a of the resin insulator 38, there is no need to use an expensive resin with adhesive properties or to pre-treat the surface of the annular yoke main member 28, such as degreasing, as in the past. This has the effect of significantly reducing costs.

In addition, since the resin insulator 38 that has no adhesive strength can be used, when a heat shock such as a cooling/heating cycle is applied, a small gap is generated at the boundary between the annular yoke main member 28 and the resin insulator 38. The stress caused by the difference in the thermal expansion coefficient of each component is eliminated,
This has the effect of solving the problem of cracks occurring in the resin insulator 38 as in the prior art.

As is clear from the above description, according to the present invention, a gap is provided between the side surface of the excitation coil and the side surface of the main yoke member, and the gap is filled with a resin insulator, so that the resin that connects the bobbin and the excitation coil is It is possible to provide a highly reliable excitation device for an electromagnetic clutch that does not peel off due to vibration.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an electromagnetic clutch equipped with a conventional excitation device, FIG. 2 is a longitudinal cross-sectional view of an electromagnetic clutch equipped with an excitation device for an electromagnetic clutch according to the present invention, and FIG. It is a front view of the shown yoke main member. 26... Excitation device, 28... Annular yoke main member,
28c... Side plate portion, 30... Annular excitation coil, 3
6... Bobbin, 28e... Protrusion, 38... Resin insulator, 38a... Hole.

Claims (1)

[Scope of Claims] 1. An annular yoke main member constituting a part of the main magnetic circuit, an annular excitation coil for generating a magnetic field, and an annular yoke main member for insulating and fixing the annular excitation coil to the annular yoke main member. In the excitation device for an electromagnetic clutch, the electromagnetic clutch has a resin insulator, and a plurality of protrusions are integrally extruded on the side surface of the annular excitation coil side of the annular yoke main member, and the annular excitation coil side surface is attached to the protrusion with an insulator. An excitation device for an electromagnetic clutch, characterized in that a gap is provided between the side surface of the annular excitation coil and a side plate portion of the annular yoke main member, and the gap is filled with a resin insulator. . 2. In the excitation device for an electromagnetic clutch according to claim 1, an annular excitation coil is wound around an annular insulating resin bobbin having an open outer peripheral surface and a substantially U-shaped cross section, and a side surface of the annular excitation coil is attached to the bobbin. An excitation device for an electromagnetic clutch, characterized in that the excitation device is brought into contact with a protrusion formed on the inner surface of a main member of an annular yoke via the side surface of the yoke.