JPS634827Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to the structure of an electromagnetic clutch, particularly an overhang type electromagnetic clutch.

[Prior Art] An overhang type electromagnetic clutch is usually used to reduce the pulley diameter. Generally, in compressors for vehicle air conditioning, etc., when the compression chamber volume is designed to be small in order to make the compressor body smaller and lighter, the desired compression capacity cannot be achieved unless the compressor is driven at a relatively high speed. . For high-speed drive, it is desirable that the pulley diameter of the electromagnetic clutch be as small as possible. However, in conventional electromagnetic clutches, the bearing, coil, and pulley are arranged in the radial direction, so the pulley diameter is the bearing diameter,
Due to restrictions such as the coil, it was not possible to make it very small. As a solution to this problem, a method was considered in which only the pulley portion protruded forward without any restriction on the inner circumferential side. This is an overhang type electromagnetic clutch. As shown in FIG. 1, a conventional overhang type electromagnetic clutch has a structure in which only the pulley 1 is brought forward in the conventional clutch shape. Therefore, although it was possible to reduce the diameter of the pulley 1, the axial distance L1 between the bearing 5 and the pulley ₁ became large, which caused a problem in the durability of the bearing. Similarly, since the position of the pulley 1 is largely moved forward with respect to the boss 6, the moment caused by the belt tension is large, causing many problems such as the pulley 1 running out and the boss 6 being deflected.

[Purpose of invention]

Therefore, it is an object of the present invention to provide an electromagnetic clutch with a small pulley diameter and a small axial distance between the bearing and the pulley.

[Structure of the idea]

According to the present invention, a magnetic rotating body is supported via a bearing on a fixed boss portion located coaxially surrounding the outer periphery of a rotating shaft of a rotating device; An armature facing the friction surface at one end is coupled movably in the axial direction, and a pulley that receives an external rotational force is coupled to the rotating body so as to cover the armature, and a magnetic flux is applied to the rotating body and the armature. In the overhang type electromagnetic clutch, the armature is connected to and separated from the rotating body by controlling the energization of the electromagnetic coil that can be applied to turn on and off the transmission of rotational force. An electromagnetic clutch is obtained which is characterized in that it is provided at a position corresponding to the above-mentioned bearing or at a position shifted toward the other end in the axial direction from the above-mentioned bearing.

〔Example〕

FIG. 2 shows an embodiment of the electromagnetic clutch according to the present invention. Referring to FIG.
It has a fixed boss portion 6 located so as to coaxially surround the outer periphery of. A magnetic rotating body 2 is rotatably supported on the outer periphery of the boss portion 6 via a bearing 5 . A recess is formed on the rear surface of the magnetic rotating body 2,
The electromagnetic coil 9 disposed in the recess is fixedly held on a fixed part of the rotating device 8. Further, a pulley 1 that receives external rotational force is fixedly held on the outer peripheral portion of the front surface of the magnetic rotating body 2. On the other hand, a hub 11 is fixed to the tip of the rotating shaft 7, and the armature 4 is supported around the hub by a leaf spring or the like so as to be slightly movable in the axial direction. The hub 11 has a shape in which the peripheral portion deviates rearward from the central portion, that is, it is shaped like a cup. The forward movement of the armature 4 is prevented by a stopper member 12 provided on the hub 11.

In this way, the armature 4 faces the friction surface 3 on the front surface of the magnetic rotating body 2 with a gap left in between. Now, when the electromagnetic coil 9 is energized while the pulley 1 is rotating, the armature 4 is attracted to the friction surface 3 of the magnetic rotating body 2 by the magnetic flux acting on the magnetic rotating body 2 and the armature 4, and the armature 4 is attracted to the friction surface 3 of the magnetic rotating body 2. As a result, the rotation of the pulley 1 is transmitted to the rotating shaft 7. Also, the electromagnetic coil 9
When the power is cut off, the armature 4 separates from the magnetic rotating body 2, and as a result, power transmission from the pulley 1 to the rotating shaft 7 is disconnected. Here, the diameter of the pulley 1 can be designed to be small without being obstructed by the bearing 5 and the electromagnetic coil 9, so high-speed driving is possible.

In such an overhang type electromagnetic clutch, the magnetic rotating body 2 is formed integrally with a cylindrical portion 13 fitted to the outer periphery of a bearing 5 and a ring plate portion 14 having a friction surface 3. In this embodiment, as is clear from a comparison between FIG. 1 and FIG. The position corresponds to the bearing 5. More specifically, the friction surface 3 is located behind the axial center of the bearing 5. As a result, the electromagnetic coil 9 is also fixed in a position moved further rearward than in the case of FIG. Further, the peripheral part of the hub 11 is inserted between the pulley 1 and the magnetic rotating body 2 while bending toward the rear,
As a result, the armature 4 supported there
is positioned so as to correspond to the bearing 5 in the radial direction. Specifically, the armature 4 is located at a position substantially corresponding to the axial center of the bearing 5.

According to the above structure, the distance _L2 from the axial center of the bearing 5 to the pulley 1 can be significantly shortened compared to the similar distance _L1 in the conventional example shown in FIG. can be kept to a minimum. Also, as a matter of course, since the position of the pulley 1 is closer to the boss 6, the problem with belt tension is solved.

Furthermore, since the peripheral portion of the hub 11 is deviated rearward, the diameter of the pulley 1 can be reduced without being hindered by the hub 11.

Note that the position of the friction surface 3 may be further shifted to the rear, and may be located further to the rear than the bearing 5.

[Effect of idea]

As explained above, the electromagnetic clutch according to the present invention reduces the burden on the bearings that support the rotating parts, eliminates belt tension problems, and shortens the distance from the center of gravity of the rotating equipment to the belt surface. This effect is achieved.

Moreover, it is also possible to make the pulley smaller in diameter.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an example of a conventional electromagnetic clutch, and FIG. 2 is a longitudinal sectional view of an embodiment of an electromagnetic clutch according to the present invention. 1... Pulley, 2... Magnetic rotating body, 3... Friction surface, 4... Armature, 5... Bearing, 7...
Rotating shaft, 8... Rotating equipment, 9... Electromagnetic coil, 1
1...Hub.

Claims (1)

[Scope of utility model registration request] A magnetic rotating body is supported via a bearing on a fixed boss portion located coaxially surrounding the outer periphery of a rotating shaft of a rotating device, while an armature facing a friction surface at one end in the axial direction of the rotating body is The central portion is fixed to the rotating shaft and is movably coupled in the axial direction to the peripheral portion of the hub that spreads outward in the radial direction, and a pulley that receives external rotational force is coupled to the rotating body so as to cover the armature. In an overhung electromagnetic clutch, the armature is coupled to and separated from the rotating body by controlling the energization of an electromagnetic coil capable of applying magnetic flux to the rotating body and the armature, thereby turning on and off the transmission of rotational force. The axial position of the friction surface of the rotating body is provided at a position corresponding to the bearing or at a position shifted toward the other end in the axial direction than the bearing, and the peripheral part of the hub is located at the other end in the axial direction with respect to the central part. The peripheral portion extends radially outward on the radially outer side of one axial end of the bearing, and the pulley extends axially outward on the outer surface of the peripheral portion. An electromagnetic clutch characterized by having small diameter clutches facing each other with a gap between them.