JPH1193986A - Clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clutch whereby transmission and interruption of torque can be switched by a simple and compact mechanism. SOLUTION: In a clutch transmitting/interrupting torque, transmitted from an output shaft of an engine to a pulley through a belt, relating to a rotary shaft of a compressor, between an inner wheel 4 of the rotary shaft and the pulley 6, an outer wheel, 8 engaged with the pulley 6 by having a space and a plurality of transmitters 9 able to roll inside thereof are provided, in an internal peripheral surface of the outer wheel 8, a cam surface 13 corresponding to the transmitter 9 is formed, at normal operation time, the transmitter 9 is brought into press contact with a central part of the cam surface 13 from one sideward to transmit torque, at abnormality high temperature time and overload action time, the transmitter 9 is moved to the other sideward, press contact with the cam surface 13 is released, so as to interrupt torque.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch for transmitting / disconnecting torque of an engine to accessories such as a car air conditioner in an automobile.

[0002]

2. Description of the Related Art Generally, a compressor of a car air conditioner is driven by torque transmitted from a crankshaft of an engine to a pulley via a belt. An electromagnetic clutch is provided between the pulley and the rotating shaft of the compressor. When an abnormally high temperature or overload occurs on the compressor side, the electromagnetic clutch is disengaged and the torque is cut off to prevent damage to the compressor. Has become.

[0003]

However, the electromagnetic clutch has a problem that the mechanism is complicated and large, and the sensor and the electric circuit are required for its control, so that the cost is high.

[0004] When an overload occurs, it is necessary to automatically cut off the torque, but it is not always necessary to automatically perform the return operation.

In view of the above, an object of the present invention is to provide a clutch which can switch transmission and cutoff of torque with a simple and compact mechanism.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a clutch for transmitting / disconnecting a torque transmitted from an output shaft of an engine to a pulley via a belt to a rotation shaft of an engine accessory. In the above, an inner ring is provided on the rotating shaft, and between the inner ring and the pulley, a plurality of engaging portions arranged in a circumferential direction engage with the pulley, and a gap between the inner ring and the pulley other than the engaging portion is provided between the inner ring and the pulley. And an outer ring having a plurality of rollers that can roll inside the outer ring. The outer ring is cam-engaged with the inner ring and the outer ring, and is held by an elastic member. As the diameter increases, the transmission element moves to release the cam engagement, thereby switching between transmission and interruption of torque.

As a mechanism for engaging and disengaging the cam engaging portion, a cam surface corresponding to the transmission element is formed on an inner peripheral surface of the outer ring,
The distance between the cam surface and the outer peripheral surface of the inner race is smaller at the center of the cam surface and larger at both ends as compared to the outer diameter of the transmitter. When one of the elastic members pushes the transmission element toward the center of the cam surface from one side (forward rotation side), and an overload is applied to the accessory, the center of the cam surface is pushed by the transmission element. It is preferable to adopt a configuration in which the outer ring expands in diameter, the transmission element moves to the other side of the cam surface, and the pressure contact state between the cam surface and the transmission element is released.

Further, if an expansion member having a larger thermal expansion coefficient than the inner ring and the outer ring is provided between the inner ring and the outer ring, the outer ring is formed by the expansion member even when the auxiliary machine becomes abnormally hot. The pusher is spread and the transmitter moves to the other side of the cam surface, and the torque is interrupted.

To return to the initial state, an overload is applied in the reverse rotation direction, and the transducer pressed against the cam surface from the other side (reverse rotation side) is returned to the normal rotation side.

The clutch can be made very compact by incorporating the inner ring and the outer ring inside the pulley.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, a rotating shaft 3 protruding from a casing 2 of a compressor 1 of a car air conditioner is provided with an inner ring 4, and a pulley 6 is rotatably fitted via a bearing 5 to the outside thereof. . A belt is stretched over the pulley 6 from the crankshaft of the engine, and the torque of the crankshaft is transmitted.

As shown in FIGS. 1 and 2, between the inner race 4 and the pulley 6, the pulley 6 is engaged with a plurality of engaging portions 7 arranged in the circumferential direction. , Pulley 6 between 7
And an outer ring 8 having an interval between the outer ring 8 and a plurality of cylindrical transmission elements 9 that can roll inside the outer ring 8. Here, the engaging portion 7 is formed by fitting a projection 10 projecting from the outer peripheral surface of the outer ring 8 into a recess 11 on the inner peripheral surface of the pulley 5. The range of movement of the transfer element 9 with respect to the outer ring 8 is restricted by the retainer 12 that rotates together with the outer ring 8.

A plurality of cam surfaces 13 corresponding to the transmitter 7 are formed on the inner peripheral surface of the outer ring 8.
Is smaller at the center of the cam surface 13 and larger at both ends than the outer diameter of the transmission 9. A spring 14 is provided on both sides of the transmission 9, and the transmission 9 is pressed toward the center of the cam surface 13 by one of the springs 14.

Further, between the inner race 4 and the outer race 8, the inner race 4 is provided.
A ring-shaped expansion member 15 made of a material having a larger thermal expansion coefficient than the outer ring 8 (for example, aluminum if the inner ring 4 and the outer ring 8 are made of steel) is provided.

According to the clutch constructed as described above, during normal operation in which the load and temperature on the engine auxiliary equipment are within the normal ranges, as shown in FIG.
, The engine torque is transmitted from the pulley 6 to the rotary shaft 3 via the outer ring 8, the transmission 9, and the inner ring 4. Is driven.

When the compressor 1 is overloaded, as shown in FIG. 3, the center of the cam surface 13 is pushed by the transmission 9 so that the outer ring 8 expands in diameter. Since it moves to the other side end and the pressure contact state between the cam surface 13 and the transmission element 9 is released, the torque is interrupted.

Also, when the compressor 1 becomes abnormally high in temperature, the outer ring 8 is pushed and expanded by the expansion member 15 so that the transmission 9 moves to the other side end of the cam surface 13 and the torque is cut off. You.

As described above, the torque is interrupted at the time of an overload operation and at an abnormally high temperature, so that the compressor 1 is prevented from being damaged.

To return the clutch to the initial state, the transmission element 9 is pressed against the cam surface 13 from the other side (reverse rotation side) by the spring 14 in the state where the torque is interrupted as described above. Therefore, an overload in the reverse direction is applied, and the transducer 9 is returned to the normal rotation side.

The clutch functions as described above regardless of the direction of rotation of the pulley 6 in any direction.

[0021]

As described above, according to the clutch according to the present invention, during normal operation in which the load and temperature on the engine auxiliary equipment are within the normal range, the transmission element is cam-engaged with the inner ring and the outer ring, When an overload is applied to the accessory, the transmission is moved and the cam is disengaged as the outer ring expands, so the torque transmission and cut-off is simple and compact compared to the electromagnetic clutch. Can be switched, and damage to the auxiliary equipment can be prevented.

If an expansion member having a larger coefficient of thermal expansion than the inner ring and the outer ring is provided between the inner ring and the outer ring, the outer ring is pushed by the expansion member even when the auxiliary machine becomes abnormally hot. The cam is disengaged and the transmission moves, the cam engagement is released, and the torque is interrupted.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a clutch according to the present invention.

FIG. 2 is a vertical sectional front view of the above.

FIG. 3 is a longitudinal sectional side view of a main part showing a transition process to a torque cutoff state according to the first embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Casing 3 Rotating shaft 4 Inner ring 5 Bearing 6 Pulley 7 Engagement part 8 Outer ring 9 Transmitter 10 Projection 11 Concave part 12 Cage 13 Cam surface 14 Spring 15 Expansion member

Claims (4)

[Claims] 1. A clutch for transmitting / disconnecting torque transmitted from an output shaft of an engine to a pulley via a belt to a rotation shaft of an engine auxiliary machine, wherein an inner ring is provided on the rotation shaft, and the inner ring, the pulley and A plurality of engaging portions arranged in the circumferential direction between the outer ring and the outer ring having an interval between the outer ring and the pulley except for the engaging portion, and a plurality of rolling elements rolling inside the outer ring. The cam is engaged with the inner ring and the outer ring, and is held by an elastic member. When the outer ring expands in diameter when an overload is applied to the auxiliary machine, the transmitter moves to engage the cam. A clutch characterized in that it is released. 2. A cam surface corresponding to the transmission element is formed on an inner peripheral surface of the outer race, and a distance between the cam surface and an outer peripheral surface of the inner race is compared with an outer diameter of the transmission element. The elastic member is disposed on both sides of the transmitter, and the transmitter is pressed toward the center of the cam surface by one elastic member. The clutch according to claim 1. 3. The clutch according to claim 1, wherein an expansion member having a larger coefficient of thermal expansion than the inner ring and the outer ring is provided between the inner ring and the outer ring. 4. The clutch according to claim 1, wherein said inner ring and said outer ring are incorporated inside said pulley.