JPS59103033A - Electromagnetic spring clutch - Google Patents

Abstract

PURPOSE:To allow a clutch to be disengaged when the titled device reaches above a certain temperature at the failure of compressor for thereby preventing an engine from the excessive imposition of load and a subsequential break-down, by constituting an armature of clutch for a car air conditioner compressor with a heat sensitive material. CONSTITUTION:Upon a shaft 3 ceasing to rotate at the breakdown of compressor, the load of shaft 3 is transmitted to a pulley 1. On the other hand, because an engine still outputs a power to cause a sliding friction at an area between a spring 7 and bosses 1c, 2b and moreover at an area between an armature 8 and the side face 1d of pulley, whereby producing a frictional heat in the vicinity of spring 7. As a result, the temperature of armature 8 rises to lower its magnetic characteristic so that the magnetic force of permanent magnet 9 can overcome. Therefore, the armature 8 moves away from the side face 1d to adhere to a flange portion 6c, whereas the diameter of spring 7 is returned to its original position to abut its outer diameter surface against the inner surface of shell 6b. In this manner, an operating safety can be ensured without the chance of load being transmitted to the side of pulley 1 or the engine at the time of breakdown.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic spring clutch that transmits torque using the tightening force of a coil spring.

Conventionally, a 1-turn sensor is installed in a car air conditioner compressor to generate pulses, and the state of the pulses is judged to determine whether the compressor is normal or not.When there is an abnormality, a clutch OFF signal is output and the bell is turned off. It has been proposed to protect the engine and vehicle by preventing the V-belt (which transmits power from the engine) from breaking, and similar measures have been considered for the application of electromagnetic spring clutches.

However, such a conventional device has the disadvantage that it requires an amplifier and a determiner to generate the pulse and determine its state, resulting in high cost. Furthermore, since it is necessary to install the rotation sensor inside the compressor and lead the lead wire to the outside, there is a drawback that it is likely to cause a seal failure.

In view of the above-mentioned conventional drawbacks, the present invention has been developed by manufacturing the armature in the electromagnetic spring clutch with a temperature-sensitive magnetic material whose magnetism significantly decreases when the temperature exceeds a certain temperature, thereby preventing the compressor from malfunctioning for some reason. If a load is applied, the clutch action will be released and this will put a burden on the engine.

The purpose of the present invention is to provide an electromagnetic spring clutch that can avoid failures.

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

1 and 2 do not show an embodiment of the present invention. In these figures, reference numeral 1 at J-3 indicates a pulley which is a rotary part on the input side. VfK 1a is formed, and an annular recess 11) and a boss 1 are formed in the center direction.
C is formed. On the other hand, an input shaft 3 of a J3-cooler compressor is fixed to the center of a hub 2, which is an output rotating member, through a key 4 and a nut 5 so as to be able to rotate integrally therewith.

Further, a flange portion 28 and a boss portion 2b are formed on the hub 2, and a similar flange portion 6 is formed on the outside of the flange portion 2a.
A cover 6 is fixed to a. The cover 6 (
A cylindrical body part 61] is formed, and a coil spring 7 having a rectangular cross section is attached to the inner peripheral side of the body part 61. Further, an armature 8 is attached to the flange portion 6C at the outermost periphery of the cover 6, and the armature 8 has a ring shape with a rectangular cross section as shown in FIG. 2, and a notch 8a is formed at one location on the inner periphery. Permanent magnets 9 are embedded in three equal parts of the circumference.

Using this magnet 9, the armadure 8 is attracted to the inside of the flange portion 6C.

One end of the coil spring 7 engages with the notch 8a, and the other end engages with a notch 2c on the outer periphery of the hub 2.

On the other hand, an electromagnetic coil 12 held by a magnetic pole piece 11 is located in the annular recess 1b of the pulley 1, which is the input rotating part '4o.
is installed. The magnetic pole piece 11 is connected to a compressor (not shown).
(Compressor) It is fixed to the flange part 13a of the flange part 13 which is fixed (or compressed) to the main body (formed integrally with the outer shell), and between the boss part 131) and the host part 1c of the pulley 1. Since two ball bearings 1/l are mounted on the pulley 1, the pulley 1 can rotate relative to the flange part 13 and the electromagnetic coil 12, which are always stationary.

Note that a small gap is always formed between the electromagnetic coil 12 and the surface of the recess 1b. Also, armadure 8 of pulley 1
A small gap 15 is also provided between the armature 8 and the side surface 1d facing the coil spring 7. Also, a small gap 15 is provided between the inner circumferential surface of the coil spring 7 and the outer circumferential surfaces of both the boss portions 1c and 2b. (There is a gap of 16°17.

Armadure 8 is made with temperature-sensitive magnetism, and has a property of 74 in which its magnetism is strong below a certain temperature T, but when its magnetism exceeds that level, it slowly decreases.

To describe the function of this configuration, when the rotational force from the engine is transmitted to the pulley 1 through the V-bell 1~, a switch (not shown) for operating the car cooler is turned ON. Unless otherwise specified, only the pulley 1 rotates. When the switch is turned on, current flows through the electromagnetic coil 12 and the armature 8 is attracted to the side surface 1d by the electromagnetic force (the electromagnetic force is much stronger than the magnetic force of the permanent magnet 9). , the gap 15 becomes zero, and the flange part 6C and armature 8 are separated 3)
-ru.

Further, due to the attachment of the armature 8 to the side surface 1d, a notch 8. The rotational force from the pulley 1 is transmitted to one end of the spring 7 via the spring 7. For this reason, the diameter of the spring 7 becomes smaller due to the winding force. (In order for this to work, settings must be made that take into account the relative relationship between the winding direction of the spring and the rotation direction of the pulley 1.) Gap 16
．． 17 becomes zero, and the inner diameter part of the spring 7 is connected to both boss parts 1.
c.

21), and the rotational force of the pulley 1 is transmitted mainly by the friction force of the 8) is transmitted to the hub 2 (via the spring 7) to rotate the input shaft 3 of the compressor.

Here, if for some reason the compressor breaks down and the input shaft 3 stops working, a large load on the shaft 3h will be transmitted to the pulley 1. On the other hand, since the rotational force from the engine side is being transmitted to the pulley 1, sliding friction occurs between the spring 7 and the boss portions Ic and 2b, and roughly between the armature 8 and the side surface 1d of the pulley 1. As a result, frictional heat is generated near the spring 7.

As a result, the temperature of the armature 8 increases, the magnetism of the armature 8 decreases, and finally the magnetic force of the permanent magnet 9 overcomes the armature 8, and the armature 8 moves away from the side surface 1d and moves toward the flange portion GC to attract the young first magnet. It will be in the state shown in the figure. Therefore, the diameter of the spring 7 returns to its original value as shown in Fig. 1, and the outer diameter surface comes into contact with the inner surface of the cylindrical body (3b). Therefore, even when the compressor switch is in the ON state, The load that would result in a failure is not transmitted to the pulley 1 or to the engine side, and safety can be ensured.

In this way, in the present invention, a coil spring that can be freely wound around the outer surfaces of the input side rotation member and the output side rotation member is installed in the cover, and one end of the spring can be magnetically attracted to the input side rotation member. In the electromagnetic spring clutch, which is locked to the armature and whose other end is locked to the output side rotation part (A), the armature is formed of a temperature-sensitive magnetic material, so that the compressor can be moved by simpler means than conventional methods. It is possible to prevent failures of the clutch itself, the engine, and other attached equipment due to failures of the engine. Also, in terms of cost, it can be significantly cheaper than conventional ones. Furthermore, since there is no need to install a rotating sensor or the like inside the compressor, situations such as seal failures do not occur.

In J5 of the above embodiment, a permanent magnet 9 is embedded in the armature 8 in order to ensure that the armature 8 separates from the side surface 1d of the pulley 1 when the clutch is disengaged. The present invention can be carried out even if the spring 7 is omitted, and the armature 8 can be hooked by the hook portion at the end of the spring 7 by actively utilizing the property that the spring 7 becomes short in the axial direction in a free state. (
It is also possible to configure it so that it can be actively pulled away from the pulley 1.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention, and FIG. 2 is a perspective view of the armature 8 shown in FIG. 1. 1... Pulley 2... Hub 6... Cover 7... Coil spring 8... Armature 9... Permanent magnet 12... Electromagnetic coil 15.16.17... Gap

Claims (1)

[Claims] ←→A coil spring that can be freely wound around the outer surface of the input side rotating part (4 and the output side rotating member) is installed in the cover, and one end of the spring is attached to an armature that can be magnetically attracted to the input side rotating member. An electromagnetic spring clutch, characterized in that the armature is formed of a temperature-sensitive magnetic material.