JPH07151168A - Electromagnetic clutch - Google Patents

Abstract

PURPOSE:To prevent generation of seizures even when excessive loads are transmitted by providing a hub member to be connected to an armature, and fixed to a rotary shaft, a cam means to transmit the load through the engagement in the rotational direction, and an elastic means to displace the cam means for the excessive load. CONSTITUTION:When an electromagnetic clutch is energized in the case of high speed or large load, the power is impulsively transmitted to each of transmission parts. A part of the rotating power from an armature 29 to a hub member 31 is transmitted by a return spring 30, while most of the rotating power is transmitted by a cam means 41 where the bearing part of the load is large at the outer circumference. Transmission of most of the shock load is buffered and avoided by the displacement in the axial direction of a cam groove 43 caused by the riding of the inclined surface based on the engagement of a cam 42 with the cam groove because the elastic displacement of a steel sheet cover 34 constituted as an elastic means 45 is generated. The weight of the cover 34 is small, and it provides the effect to reduce the shock force based on the reduction of the inertia force. Thus, the slip by the friction can be prevented, and no seizure is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic clutch provided in a rotary machine such as a compressor of an air conditioner for automobiles.

[0002]

2. Description of the Related Art Conventionally, an electromagnetic clutch has been widely used as a device having a function of transmitting or cutting off power from a driving side on a concentric shaft to a driven side by electromagnetic operation.

[0003] The general one is the opposite one or two.
This is because one or more circular friction surfaces are pressed (compressed) by an electromagnetic force, torque is transmitted by the friction force, and the spring is returned when released.

Now, an example of a conventional general single plate fastening type electromagnetic clutch will be described with reference to FIG.

A stator 2 is fixed to a housing 1 of a rotary machine such as a compressor, and an exciting coil 3 is built in the stator 2. The rotor 4 accommodates the stator 2 in the space 5, receives the power of the engine (not shown) by the belt connection of the pulley 6 on the outer circumference, and is rotatably positioned by the bearing 7 in the housing 1 and is axially positioned. It is installed in a closed state. An armature 9 is provided facing the friction surface 8 of the rotor 4 with a slight gap. Armature 9
Is connected to the center hub 11 by a return spring 10 so as to be able to transmit rotational force. The center hub 11 is a combination of a boss portion 13 splined to a rotary shaft 12 of a rotary machine and an end plate 14, and is attached by fastening the end plate 14 to the rotary shaft 12 with a bolt 15. Rotating shaft 12
Is rotatably mounted on the housing 1 while being axially positioned.

When the engine power is transmitted to the rotating machine, a current is passed through the exciting coil 3 to excite it and the armature 9
Is absorbed by the rotor 4, engine power is transmitted to the pulley 6, the rotor 4, the friction surface 8, the armature 9, the return spring 10, the center hub 11, and the rotary shaft 12. When the electric current is cut off, the armature 9 is separated due to the elastic return of the return spring 10, the power is cut off, and the rotating machine is released.

The conventional electromagnetic clutch is thus simple,
It is widely used for general industry because it has a small structure and there are few restrictions on its use. (See Japanese Utility Model Publication No. 4-24182).

[0008]

However, in this conventional electromagnetic clutch, the friction surface slips to cause seizure when electromagnetically actuated when an excessive load is transmitted, such as when the drive side is in a high rotation state. There is a problem that the power transmission component is damaged or broken.

This is because an excessive load (torque) is transmitted from the rotor to the center hub via the armature and the return spring, and these are connected rigidly in the rotational direction, so that the transmission is instantaneous. Is.

Therefore, according to the present invention, even when an excessive load is transmitted, transmission is not performed instantaneously,
It is an object of the present invention to solve the above-mentioned problems and to provide an electromagnetic clutch in which the friction surface does not slip, does not cause seizure, and does not damage or damage the power transmission component.

[0011]

In order to achieve the above object, the present invention provides a stator having a built-in exciting coil fixed to a housing of a rotating machine and a space for accommodating the stator. A rotor that is connected to a drive source and is rotatably mounted in the housing in a state of being axially positioned; and an armature that is attracted to the rotor when the exciting coil is energized and returns when deenergized. A hub member connected to the armature and fixed to the rotary shaft of the rotating machine, and a cam formed as a part or the whole of a connecting portion between the hub member and the armature to transmit a load by rotational engagement. Means and elastic means for displacing the load by displacing the portion of the cam means in the axial direction against an excessive load,
According to a second aspect of the present invention, the hub member is formed by a sheet metal cover, and the elastic means is formed by a part of the cover, and the third aspect is the cam means. Comprises a ball that is capable of projecting and retracting in one of the holes of the hub member and the armature and a groove that is provided in a portion facing the other ball, and the elastic means urges the ball to project. As described above, the coil spring is provided in the one hole as described above.

[0012]

The armature is attracted to the rotor by energizing the exciting coil, and the power is transmitted to the hub member and the rotating shaft through the connecting portion. When not energized, the armature returns and power is not transmitted. Here, the one according to claim 1 is
When the power load becomes excessive and acts momentarily on the connecting portion, the action is exerted on the cam means formed as a part or the whole of the connecting portion, and the portion is displaced axially by the elastic means. , To prevent the transmission of instantaneous load. As a result, excessive loads are evenly arranged and transmitted to prevent slipping, seizure, or damage or breakage of parts. In addition to the above actions, the second aspect of the present invention can reduce the weight, so that the impact load can be further reduced. According to the third aspect, in addition to the action of the first aspect, it can be easily machined.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.
Will be described. First, the configuration will be described with reference to FIG. 2, which is a cross section taken along line II-II of FIG. In the following description, it is assumed that the rotary machine in this embodiment is a compressor of an air conditioner for an automobile and its power is an engine of the automobile.

The compressor housing 21 is attached to an engine (not shown), and a rotary shaft 32 for compressing the refrigerant is rotatably and axially positioned at the center of the engine. The bracket 22 is attached to the stepped boss portion of the housing 21.
a and the yoke 22b made of iron, the stator 22 has the pin 3
6 and a ring 37, and the exciting coil 23 is built in the yoke 22b.
It is designed to be de-energized.

The iron rotor 24 is mounted on a small boss portion at the tip of the housing 21 by a bearing 27 so as to be rotatable and axially positioned. The rotor 24 has a space 25 on the back surface, in which the yoke 22b of the stator 22 is accommodated in a floating state. The rotor 24 is provided with a pulley 26 on the outer periphery, is belted around the pulley 26, and is rotationally driven by the engine. The rotor 24 has a circular friction surface 28 on the surface, and a multi-plate plate 39 connected to each other is interposed between the rotor 24 and a friction surface 38 of an iron armature 29 which is attracted (compressed) thereto.

The hub member 31 is made of a metal plate such as a steel material and is formed as a substantially disc-shaped cover. The deep-drawing boss portion 33 is spline-coupled to the rotary shaft 32, and then the washer 40 is interposed. The end plate portion 34 is fixed to the rotary shaft 32 by tightening it with bolts 35.

The hub member 31 and the armature 29 are connected at their inner parts by a return spring 30 and then at their outer parts by a cam means 41. The cam means 41 has a function of increasing the thrust force to the suction side of the armature 29, and bears the clutch connecting force.

As shown in FIG. 1, the return spring 30 is formed by arranging, for example, four spring plates having a substantially triangular shape in equal parts, and is riveted to easily bend in the axial direction. It is provided so that.

The cam means 41 has, for example, 4
The armature 29 is provided with a cam 42 having an inclined surface in the direction of rotation in a protruding manner, and a cam groove 43 having a similar inclined surface is punched by a press on the end plate portion 34 of the portion facing the arm 42. Form and configure (see FIG. 3). The return spring 30 and the cam means 41 as the power (load) transmitting portions of the armature 29 and the hub member 31 are arranged in the rotating machine (compressor) in terms of the location, the number, the size, and the distribution of the respective transmission forces. It is appropriately determined according to the specifications. Further, in FIGS. 1 and 2, reference numeral 44 denotes a rubber stopper provided on the end plate portion 34 for buffering a surface collision with the armature 29, which is also appropriately provided.

The cam groove 43 is provided in the end plate portion 3 which is a sheet metal cover.
As described above with reference to FIG. 4, when the armature 29 is impacted in the direction of arrow P, the corresponding portion of the end plate portion 34 near the cam groove 43 is formed as shown in FIG. The elastic means 45 is also provided, which is displaced in the axial direction as shown by the dotted line and releases the impact load.

Next, the operation of the above embodiment will be described. When the exciting coil 23 is excited by energization, the armature 29 is attracted to the rotor 24, and the multi-plate 39 is rubbed against the friction surface 38.
Then, it is pushed and pressed against the friction surface 28 of the rotor.

Therefore, the rotational power of the engine is transmitted to the pulley 26, the rotor 24, and the armature 29 via a belt (not shown). The rotational power of the armature 29 is transmitted from the return spring 30 and the cam means 41 to the hub member 3
1 is transmitted to the rotary shaft 32 connected to the spline, the compressor is operated, and the air conditioner of the vehicle is operated. In this case, the transmission force can be increased based on the increase in the pressure-bonding force by the cam thrust of the cam means 41. When the air conditioner is not used, since the armature 29 is not attracted to the rotor 24 due to the interruption of the current to the exciting coil 23, the armature 29 is separated from the crimping friction surface by the restoration of the return spring 30, and the armature 29 and the hub member 31 are separated.
Also, the rotary shaft 32 is freely opened, and the operation of the compressor stops.

Therefore, when the engine is rotating at high speed or the compressor load is large when the refrigerant of the air conditioner is in a liquid state (when the outside air temperature is low), an electromagnetic force is applied to operate the compressor for air conditioning. When the clutch is energized, the engine power is transmitted shockfully to each transmission component.

In such a case, in this embodiment, the rotary power is transmitted from the armature 29 to the hub member 31 by a part of the return spring 30, and most of the cam means 41 is provided on the outer circumference for a large load. Will be held in. Moreover, most of the impact load is transmitted by the cam 42.
The axial displacement of the portion of the cam groove 43 due to the climbing of the inclined surface based on the engagement of the cam groove 43 with the cam groove 43 is the elastic displacement of the sheet metal cover (end plate portion) 34 configured as the elastic means 45. Since this displacement occurs, buffering is avoided. Therefore, the above-mentioned excessive load is prevented from being instantaneously transmitted, and the load is transmitted in a state where the loads are evenly arranged.

Further, in the present embodiment, since the hub member 34 is made of sheet metal, the weight is also lightened, the weight of the electromagnetic clutch can be reduced, and the impact force is reduced due to the reduction of inertial force. It also has an effect.

As a result, in the present embodiment, when an excessive torque is input, the cover is further deformed, the cam portion can slide like a ratchet and the force can be released, slippage on the friction surface can be prevented, and seizure occurs. It is possible to prevent the rotation shaft 32, which is a power transmission component, from being damaged or broken.

4 and 5 show the second embodiment. In this embodiment, a cam means 46 having a circular cross section is provided at the outer peripheral engaging portion between the armature 29a and the end plate portion 34a, and the rest is the same as in the first embodiment. The cam means 46 is provided with a circular protruding cam 47 on the armature 29a side, and a circular cam groove 48 having a radius larger than the circular radius at the portion of the disk portion 34a facing each other. 48 is formed by press embossing.

In the case of the second embodiment, as shown in FIG. 5, the thrust exerted on the disc portion 34a by the input from the armature 29a (in the direction of arrow P) is T depending on the input torque.
_Since it changes from ₁ to T ₂ and an excessive load is gradually released, the clutch is connected slowly and the power transmission to auxiliary machines such as compressors is made smoother. As a result, it is possible to prevent the friction surface from slipping and seizing, and to prevent the power transmission parts of the auxiliary machine from being damaged.

FIG. 6 shows a third embodiment. This example
The cam groove 50 is provided on both the armature 29b and the end plate portion 43b.
And 51 are provided, and a ball 49 is mounted between them, and the others are the same as in the previous embodiment. In this embodiment, the cam groove 50 only needs to be provided on the armature 29b side, which facilitates manufacturing.

7 and 8 show a fourth embodiment. In this embodiment, the armature 52 and the hub member 53 are connected only by the cam means 54 (4 places on the circumference) provided on the outer peripheral portion. The housing 21, the stator 22, the exciting coil 23, the rotor 24, the bearing 27, the rotary shaft 32, and the multi-plate plate 39 are the same as those in the previous embodiment. Armature 5
The reference numeral 2 designates a disc portion 55 serving as a suction portion and a central cylindrical boss portion 56.
Is integrally formed with the housing 21, and is biased to the left by a return spring 57 at the insertion end of the housing 21 in the boss (on the right side in the drawing) so that it can relatively slide on the boss 58 of the hub member 53. It is installed. The hub member 53 is the rotating shaft 3.
It is configured by a shaving member (having a large rigidity) that has an end plate portion 59 integrally with a boss portion 58 that is spline-connected to the second member 2 and is fastened with a bolt 35.

As shown in FIG. 8, the cam means 54 is provided with a hole 63 on the armature 52 side at a right angle to the outer periphery of the disk portion 55, a ball 60 is inserted therein, and a coil spring (elastic means) 30 is used. It is provided so as to urge it to the outside. On the other hand, on the hub member 53 side, the cam groove 61 is formed in the end plate portion 59 of the facing portion.
To be engaged with the ball 60.

The operation of the fourth embodiment is as follows. That is, when the exciting coil 23 is excited, the armature 52 is attracted to the rotor 24 via the multi-plate plate 39. At this time, the boss portion 56 of the armature 52 contracts the right return spring 57 and slides slightly on the boss portion 58 of the hub member in the axial direction (right side). The rotating force of the rotor 24 is transmitted to the multi-plate plate 39 and the armature 52,
The cam means 54, that is, the hole 63 of the disc portion 55, the ball 6
It is transmitted to the end plate portion 59, the boss portion 58, and the rotary shaft 32 through 0 and the cam groove 61.

Here, when an excessive load is momentarily applied, thrust is generated in the cam means 54, and the ball 60 enters the hole 63 against the coil spring 62.
This transmission of excessive load can be avoided. Therefore, instantaneous power transmission can be prevented, smooth clutch connection can be performed, and seizure or damage to parts due to slippage can be prevented.

The fourth embodiment has an effect that it can be easily manufactured by machining.

[0035]

As described above, according to the present invention, it is possible to smoothly connect the electromagnetic clutch and avoid the transmission of an excessive load.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a partial view taken along the arrow III in FIG.

FIG. 4 is a partial view showing a second embodiment and corresponding to FIG.

FIG. 5 is an enlarged detailed view of FIG.

FIG. 6 is a partial view showing a third embodiment and corresponding to FIG.

FIG. 7 is a sectional view showing a fourth embodiment and corresponding to FIG.

FIG. 8 is a detailed view of the portion shown in the arrow VIII of FIG.

FIG. 9 is a sectional view of a conventional one.

[Explanation of symbols]

 1 Housing 2 Stator 3 Excitation Coil 4 Rotor 5 Space 6 Pulley 7 Bearing 8 Friction Surface 9 Armature 10 Return Spring 11 Center Hub 12 Rotating Shaft 13 Boss 14 End Plate 15 Bolt 21 Housing 22 Stator 23 Excitation Coil 24 Rotor 25 Space 26 Pulley Bearing 28 Friction surface 29 Armature 30 Return spring 31 Hub member 32 Rotating shaft 33 Boss portion 34 End plate portion 35 Bolt 36 Pin 37 Ring 38 Friction surface 39 Multi-plate plate 40 Washer 41 Cam means 42 Cam 43 Cam groove 44 Stopper 45 Elastic means 46 cam means 47 cam 48 cam groove 49 ball 50 cam groove 51 cam groove 52 armature 53 hub member 54 cam means 55 disk part 56 boss part 57 return spring 58 boss part 59 Plate portion 60 the ball 61 cam groove 62 coil spring (resilient means) 63 holes

Claims (3)

[Claims] 1. A stator having a built-in excitation coil fixed to a housing of a rotating machine, and a space for accommodating the stator, connected to a drive source, and rotatably positioned in the housing in an axial direction. A rotor to be mounted, an armature that is attracted to the exciting coil when the exciting coil is energized and returns to the non-energizing state, a hub member that is connected to the armature and is fixed to a rotating shaft of the rotating machine, and the hub. A cam means which is formed as a part or the whole of a connecting portion between a member and the armature and transmits a load by engagement in a rotational direction, and a portion which transfers the load by axially displacing the cam means portion against an excessive load. An electromagnetic clutch comprising elastic means capable of escaping the vehicle. 2. The electromagnetic clutch according to claim 1, wherein the hub member is formed by a cover made of sheet metal, and the elastic means is formed by a part of the cover. 3. The cam means comprises a ball provided in a hole in one of the hub member and the armature so as to be retractable, and a groove provided in a portion facing the other ball, and the elastic means is provided. The electromagnetic clutch according to claim 1, wherein the electromagnetic clutch is a coil spring provided in the one hole so as to urge the ball to project.