JPH0234505Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the structure of an electromagnetic clutch, and more particularly, to an electromagnetic clutch having a structure for use in an automobile air conditioning compressor and for protecting automobile accessories.

[Conventional technology]

If an automobile air conditioning compressor becomes unable to rotate due to seizure or the like, it is conceivable that other rotary drive elements will be adversely affected. Particularly recently, there are many cases in which a single drive belt drives the compressor together with automobile accessories such as an alternator and oil pump, and the inability of the compressor to rotate immediately leads to the above-mentioned devices stopping or becoming unstable. As a result, this has become a major problem in the driving of automobiles.

Also, even if we consider only the compressor, for example, if the compressor becomes unable to rotate due to seizure, etc., sliding friction will occur between the rotor of the electromagnetic clutch and the suction plate, and over time, frictional heat will cause Problems arise such as the red-hot rotor and suction plate seizing, and rotor bearings burning out.

Conventionally, as a means to solve such problems, a temperature fuse is installed near the suction surface of the electromagnetic clutch attached to the compressor body, thereby reducing the heat of sliding friction between the rotor and suction plate that occurs when the compressor stops abnormally. A mechanism is known in which the temperature is sensed and a temperature fuse is actuated (blown) to cut off the current to the electromagnetic clutch, thereby causing the rotor and the suction plate to dissociate, causing the rotor to idle, thereby avoiding the above-mentioned problem.

[Problem that the invention attempts to solve]

However, with the above mechanism, it is impossible to attach the temperature fuse in direct contact with the suction surface, so there is a considerable difference between the heat generated by sliding friction between the suction surfaces and the temperature actually sensed by the temperature fuse. will appear. Furthermore, the temperature fuse may sense and operate due to the heat generated by the compression itself, making it difficult to operate the temperature fuse accurately in accordance with the temperature of the suction surface.

In other words, the temperature fuse malfunctions frequently.

Furthermore, since the temperature fuse stops the function of the electromagnetic clutch by blowing, the temperature fuse itself must be replaced in order to recover from a failure, making maintenance difficult. Naturally, recovery from malfunction also requires replacement, so such a mechanism, which frequently malfunctions, is even more problematic in terms of maintenance.

[Means for solving problems]

Therefore, the present invention includes a rotor that is rotationally driven by a drive source, a suction plate placed opposite the rotor, an excitation coil disposed in a space provided on the side of the rotor, and a cross section that covers the excitation coil. It has an excitation coil device consisting of a U-shaped ring-shaped core and a ring-shaped mounting plate that fixes the bottom surface of the U-shaped part of the ring-shaped core to the compressor body. generate a magnetic flux that includes the ring-shaped core, the rotor, and the attraction plate as a magnetic path so that the attraction plate is attracted to the rotor;
Furthermore, one end is fixed between the hub fixed to the drive shaft and a stopper plate placed opposite to the suction surface of the suction plate, and the other end is fixed to the stopper plate, which is placed opposite to the suction surface of the suction plate. In an electromagnetic clutch equipped with a plurality of leaf springs fixed on the outer periphery, a self-returning temperature switch is provided near the suction surface of the rotor, and a heat-melting material is applied to the surface of the suction plate opposite to the suction surface. The electromagnetic device is characterized in that the tip thereof is in contact with the stopper plate, and that the operating temperature of the self-resetting temperature switch is the same as or higher than the melting temperature of the hot melting material. The problems of the prior art have been solved by providing a clutch.

〔Example〕

Next, an embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows the electromagnetic clutch obtained according to the present invention installed in an automobile air conditioning compressor.

First, a main shaft lead-out cylinder 1 is formed protruding from the compressor main body 2 so as to concentrically surround the main shaft 11, and a rotor 4 is rotatably fitted into the outer peripheral surface of the main shaft through a ball bearing 3. The rotor 4 has a U-shaped cross section by closing one open end of a concentric double cylinder with an annular flat plate. The outer surface of the annular flat plate portion is formed as an attraction surface 5 and has a magnetic flux blocking slit 101.
is formed by drilling. Further, a V-belt groove 6 for tensioning a V-belt (not shown) is provided on the outer periphery of the large-diameter cylindrical portion of the concentric double tube. Further, a ring-shaped core 8 having a U-shaped cross section and containing an excitation coil 7 is disposed in the interior space having a U-shaped cross section, and is fixed to one surface of an annular fixing plate 9. The fixed plate 9 is fixed on the other side to the compressor body 2 so as to be concentric with other rotating parts. The self-resetting temperature switch 40 is disposed in the ring-shaped core 8 near the inner side of the suction surface 5 of the rotor 4 so as to easily sense the sliding friction heat generated between the rotor 4 and the suction plate 15. In this embodiment, the rotor 4 is integrally formed with a concentric double cylinder and an annular flat plate.

A hub 12 is formed integrally with the hub 12 at the end of the main shaft 11 protruding from the main shaft lead-out cylinder 1.
It is fixed by a half-moon key 22 and a nut 23 together with a flange 13 extending on the circumference. Further, an annular suction plate 15 is disposed concentrically with the flange 13 outside the outer circumference of the flange 13, facing the suction surface 5 of the rotor 4 with a predetermined gap therebetween.
Similarly to the attraction surface 5 of the rotor 4, a magnetic flux blocking slit 102 is formed in the attraction surface 105 of the rotor 5. One end of the leaf spring 16 is fixed with a rivet 18 near the outer periphery of the surface opposite to the surface that attracts the rotor 4 of the suction plate 15, and the other end is fixed near the outer periphery of the outer surface of the flange 13. , Watshiya 1
9, leaf spring 16, and stopper plate 20 are stacked in this order and then fixed with rivets 17. As a result, the suction plate 15 is elastically supported by the flange 13 via the leaf spring 16. Note that such elastic support via the leaf springs 16 is provided at a plurality of locations.

A plurality of wide shallow holes 103 with a depth of about 2 mm and a diameter of about 6 mm are formed in a plurality of evenly spaced holes on the opposite surface of the suction plate 15 from the surface that attracts the rotor 4, and lead or thermoplastic resin is filled into the holes 103. A heat-melting material 30 such as the like is placed by press-fitting or the like, and a cylindrical part 104 smaller than the hole diameter is provided to protrude from the press-fitting part toward the stopper plate 20, and its tip abuts against the stopper plate 20. As a result, the suction plate 15 elastically supported by the flange 13 via the leaf spring 16 is brought close to the suction surface 5 of the rotor 4. The height of the cylindrical portion 104 is set so that the gap between the suction surface 5 of the rotor 4 and the suction surface 105 of the suction plate 15 at this time becomes an optimum gap.

Next, the operation of the present invention will be explained based on examples.
When the excitation coil 7 is energized, a magnetic flux is generated that passes through the rotor 4, the ring-shaped core 8, and the attraction plate 15, and an attraction force acts on the attraction plate 15 in the direction of the attraction surface 5 of the rotor 4. When the force becomes larger than the elastic reaction force of the leaf spring 16, the rotor 4 is attracted to the attraction surface 5 of the rotor 4. When the suction plate 15 is attracted to the suction surface 5 of the rotor 4, frictional torque is generated, and the rotational movement of the rotor 4 is caused by the suction plate 15, the leaf spring 16, the flange 13, and the hub 1.
2. It is transmitted to the main shaft 11 and the compressor is driven.
When an abnormal stop occurs in the compressor, for example, when the compressor becomes unable to rotate due to seizure, the suction surface 105 of the suction plate 15 and the suction surface 5 of the rotor 4 begin to slip, and the heat generated by the sliding friction is absorbed by the suction plate 15. This causes the rotor 4 to rapidly heat up. When the melting temperature of the hot melt material 30 is reached, the wide shallow hole 103 of the suction plate 15
The heat-melting material 30 press-fitted into the stopper plate 20 is melted, and the contact with the stopper plate 20 is released. Then, the temperature rises further and the self-resetting temperature switch 4
When the temperature reaches the off set temperature of 0, the self-resetting temperature switch 40 is turned off, the current to the excitation coil 7 is cut off, and the suction plate 15 is separated from the suction surface 5 of the rotor 4 due to the elastic reaction force of the leaf spring 16. At this time, the gap between the attraction surface 105 of the attraction plate 15 and the attraction surface 5 of the rotor 4 is a distance that cannot be attracted by the magnetic force generated in the excitation coil 7 due to the melting of the hot melt material 30. Therefore, even if the self-resetting temperature switch 40 is reset and the excitation coil 7 is energized again, the suction plate will not be attracted to the suction surface 5 of the rotor 4, and the rotor 4 will be free to rotate. It is possible to avoid stopping the operation of other automobile accessory devices due to an abnormal stop, and it is possible to ensure the safety of driving the automobile. Further damage to the electromagnetic clutch can also be avoided.

The operating temperature of the self-resetting temperature switch 40 can be freely changed by changing the set value, and the melting temperature of the hot melting material 30 can be changed by selecting the material.

[Effect of idea]

In the compressor protection mechanism of the present invention, a hot melt material is arranged on the opposite side of the suction plate of the electromagnetic clutch from the suction surface, and the hot melt material can be treated as an integral part of the suction plate. As a result, the temperature of the heat generated due to sliding friction between the suction surfaces and the temperature of the hot melt material can be almost the same, and since it is not affected by the heat generation of the compressor itself, the temperature of the suction surface can be adjusted accurately and practically. This has the effect of preventing the electromagnetic clutch from functioning.

Furthermore, since a self-resetting temperature switch is used as a device disposed near the rotor's suction surface to turn off the power to the electromagnetic clutch, even if this switch malfunctions and turns off the power to the electromagnetic clutch, Since the electromagnetic clutch self-resets and turns on the current, it does not require replacement each time the electromagnetic clutch is turned off, providing an excellent maintenance effect.

In this way, by combining the heat-melting material and the self-resetting temperature switch, it was possible to create a compressor protection mechanism that is highly accurate and easy to maintain.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment in which an electromagnetic clutch obtained according to the present invention is attached to an automobile air conditioning compressor. 1...Main shaft lead-out tube, 2...Compressor main body, 4...
Rotor, 5,105... Attraction surface, 7... Excitation coil, 8... Core, 11... Main shaft, 12... Hub,
15... Suction plate, 16... Leaf spring, 17, 18...
... Rivets, 20 ... Stopper plate, 30
...Hot melting material, 40...Self-resetting temperature switch, 103...Wide mouth shallow hole.

Claims (1)

[Claims for Utility Model Registration] (1) A rotor rotationally driven by a drive source, a suction plate placed opposite the rotor, and an excitation plate placed in a space provided on the side of the rotor. The excitation coil device includes a coil and a ring-shaped core having a U-shaped cross section that covers the excitation coil, and a ring-shaped mounting plate to which the bottom surface of the U-shaped portion of the ring-shaped core is fixed to the compressor body. By energizing, a magnetic flux is generated around the excitation coil that includes the ring-shaped core, the rotor, and the suction plate as a magnetic path, and the suction plate is attracted to the rotor. A plurality of leaf springs are provided, one end of which is fixed between a stopper plate disposed facing the surface opposite to the suction surface, and the other end fixed on the outer periphery of the surface of the suction plate opposite to the suction surface. In this electromagnetic clutch, a self-resetting temperature switch is disposed near the suction surface of the rotor, and a heat-melting material is disposed on the surface opposite to the suction surface of the suction plate, the tip of which is connected to the stopper plate. A protection mechanism for a compressor, characterized in that it is in contact with. (2) The compressor protection mechanism according to claim 1, wherein the operating temperature of the self-resetting temperature switch is set to be equal to or higher than the melting temperature of the hot melt material.