JPS60121326A - Electromagnetic spring clutch - Google Patents

Abstract

PURPOSE:To greatly lengthen the life of an electromagnetic clutch, by winding a helical spring only on the cylindrical surface of an input rotor to transmit torque from the rotor to an output hub to avoid impulsively engaging the clutch. CONSTITUTION:When a voltage is applied to an electromagnetic coil 2, an armature 150 is magnetically attracted so that the armature is rotated together with the friction surface 1b of an input rotor 1. A helical spring 206 is wound on the winding surrace 1a of the input rotor 1 by the rotation of the armature 150 to transmit the torque of the input rotor to a guide 272 through the helical spring to rotate an output hub 204 and a rotary shaft 104. Since the helical spring 206 is wound only on the winding surface 1a of the input rotor 1, the number of the wound turns of the spring can be set at a value only necessary for the transmission of the torque, so that an electromagnetic clutch is prevented from being impulsively engaged due to a large spring constant.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a refrigerant compressor installed between the rotating shaft of a refrigerant compressor and an output element of an engine in order to intermittently drive a refrigerant compressor of, for example, an automobile air conditioner. This invention relates to an electromagnetic spring clutch.

(Prior Art) As shown in the longitudinal cross-sectional view of FIG. 1, a conventional electromagnetic spring clutch includes an input rotor 1 which is a rotary driving body, and a yoke built into the input rotor 1 and attached to a front housing 101 of a compressor. By applying voltage to the excitation coil 2 attached by the circlip 108 via the inner race of the stay 2a, the stay 2b, and the bearing 109, and the magnetic circuit section around the excitation coil 2,
An armature 15 that is magnetically attracted and frictionally engaged with a friction surface 1b provided on one end surface of the human-powered rotor 1 and rotates together.
0 and a notch 151 formed in this armature 150.
One hook part 6a is engaged with the other hook part 6b, and the other hook part 6b is rotated.The output (2) is a driven body.The coil spring 6 is engaged with a notch 41 provided in the hub 4, and the coil 2 is energized. When this occurs, the coil spring 6 is wound around the cylindrical spring winding surface 1a protruding from the input rotor 1 in the axial direction and the outer peripheral surface 4a of the output hub 4, and this tightening force causes the torque of the input rotor 1 to be applied to the output hub. 4 and further fixed to the output hub 4 by a key 102 and a nut 103.
transmitted to. Further, the coil spring 6 is housed in a spring cover 170 that is concentrically attached to the output hub 4, and the armature 150 is housed in a spring cover 170 that is mounted concentrically on the output hub 4.
It is supported by a flange 171 on the input rotor side of 70. Furthermore, the input rotor 1 is supported by a bearing 109 attached to the outer periphery of the front housing 101 of the compressor, and the bearing 109 is fixed to the outer periphery of the front housing 101 by a circlip 108. When the excitation coil 2 is de-energized, the permanent magnet 173 fixed to the flange 171 of the spring cover 170 by adhesive etc. (3) attracts the armature 150 to the spring cover 170 and returns the spring 6 to its original shape. I'm bringing it back.

However, in the conventional electromagnetic spring clutch having the above configuration, when the coil spring 6 wraps around the cylindrical spring winding surface 1a of the input rotor 1 and the outer peripheral surface 4a of the output hub 4, the rotation shaft 104 of the compressor Impact torque is generated, which causes noise in the vehicle interior and reduces the passenger's feeling, and at the same time damages the joint between the output hub 4 and the rotary shaft 104 of the compressor by the key 102, significantly shortening its lifespan. I was letting it happen. In addition, as the clutch is repeatedly engaged and engaged, the coil spring 6, the winding surface 1a of the coil spring 6, and the outer circumferential surface 4a of the output hub 4 wear out, and when this wear becomes severe, the winding surface 1a and the outer peripheral surface 4a of the output hub 4 become worn. The coil spring 6 enters the gap g between the abutting portions of the output hub 4, and at this time a slat load is applied to the output hub 4, which has a disadvantage that it adversely affects the durability of the compressor.

(4) (Object of the Invention) In view of the above-mentioned problems, the present invention has a structure in which the coil spring is wound only around the cylindrical winding surface of the input rotor, thereby reducing the impact torque at the time of connection and at the same time The purpose is to eliminate the problem of biting into the gap g.

(Example) Next, the present invention will be described in detail with reference to the accompanying drawings.

2, 3 and 4 show an embodiment of the present invention, in which an excitation coil 2 is built into the input rotor 1 through a small gap, and the excitation coil 2 includes a yoke 2a, The stay 2b is attached to a front housing 101 of an automobile compressor by a circlip 108 via an inner race of a bearing 109. The input rotor 1 has a bearing 10 attached to a front housing 101 of an automobile compressor.
It is rotatably supported via 9.

A key 1 is attached to the rotating shaft of the compressor, that is, the driven shaft 104.
An output hub 204 is fixed with a nut 103 via a nut 103.

(5) A friction surface 1b is formed on one end surface of the input rotor 1, and an armature 150 is disposed facing each other on this friction surface 1b.
1, a hook portion 206a at one end of the coil spring 206
is locked, and the hook portion 206b at the other end of this coil spring 206 is engaged with the notch 273 of the spring guide 272.
It is locked to. The coil spring 206 is located only on the outer periphery of the cylindrical winding surface 1a that protrudes from the friction surface 1b of the human-powered rotor 1 toward the output hub 4 side.

The guide 272 has a generally annular shape as a whole, and after the coil spring 206 is inserted and locked, the guide 272 is press-fitted onto the outer circumferential surface of the output hub 204, and is then welded by a method such as arc welding. Fixed. A stopper 274 that prevents the coil spring 206 from moving toward the friction surface lb of the input rotor 1 is integrally formed on the guide 272 .

In addition, the input rotor 1 receives power extracted from a drive source (for example, an automobile engine) (not shown) via a belt (not shown), and the magnetic flux generated when voltage is applied to the excitation coil 2 is applied to the circle of the human-powered rotor 1. It bypasses the arc-shaped slit IC, passes through the armature 150, and generates a magnetic attraction force.

A groove 1d into which the belt fits is provided on the outer periphery of the input rotor 1.

In this example, the input rotor 1, the yoke 2a around the excitation coil 2, the armature 150, the coil spring 206, and so on form a magnetic circuit. Both the guide 272 and the output hub 4 are made of iron-based material.

Note that a plurality of permanent magnets 173 are fixed to the back side of the armature 150 of the guide 272 by adhesive or the like.
When the excitation coil 2 is deenergized, the armature 150 is attracted and held by the magnet 173. The guide 272 is provided with a protrusion 275 that protrudes toward the inner circumferential side of the armature 150.
The outer circumferential surface of the armature 150 supports the inner circumferential surface of the armature 150, thereby suppressing eccentricity of the armature 150 during operation. This protrusion 275 includes (7) one end 2 of the coil spring 206 as shown in FIG.
A slit 276 is provided so that one end 206a can move by a predetermined angle necessary until the winding of 06a is completed.

Next, the operation of this embodiment in the above-described configuration will be explained.

First, when a voltage is applied to the excitation coil 2, the magnetic circuit and armature 150 around it are excited, and as a result, the armature 150 is magnetically attracted and rotates together with the friction surface 1b of the input rotor 1, and the armature 150 rotates. The coil spring 206 is wound around the winding surface 1a of the input rotor 1, and the rotation of the input rotor 1 is transmitted to the guide 272 via the coil spring 206, and further to the compressor via the output hub 204 integrated with the guide 272. is transmitted to the rotating shaft 104 of. Here, in the present invention, since the coil spring 206 is wound only around the winding surface 1a of the input rotor 1, the number of turns of the coil spring 206 can be set only to the number of turns necessary for torque transmission. In the conventional example, the hook portion 6b at one end of the coil (8) spring 6 is locked in a notch 41 provided on the outer periphery of the output hub 4, so the number of turns of the coil spring 6 is approximately twice the number of turns of the present invention. It is. In general, the spring constant of the coil spring 206 in the torsional direction increases as the number of turns decreases, but the inventor has confirmed through experiments that at this time, the impact torque during connection also decreases significantly.

The present invention focuses on this characteristic, and corresponds to the case where the number of turns on the output hub 4 side is set to zero, which is the minimum number of turns necessary for torque transmission, and the cylindrical winding surface 1a of the input rotor 1 is However, the coil spring 206 is wound to transmit torque, and as a result, the spring constant of the coil spring 206 becomes large, which alleviates the phenomenon of the coil spring 206 being impulsively wound during connection.
It was confirmed that the impact torque was almost completely eliminated.

Next, when the power to the excitation coil 2 is cut off, the armature 150 returns to its original position due to the attractive force of the permanent magnet 173, and the coil spring 206 is returned to its original position due to its self-returning force, thereby reliably releasing the torque transmission. .

(9) In the above embodiment, the coil spring 206 is attached to the guide 272 fixed to the output hub 204 by welding or the like.
However, as shown in FIGS. 5 to 7, the hook portion 2 of one end of the coil spring 206 is fixed to the slit window 371 provided in the spring cover 370.
06b, and then a ring 380 is press-fitted and fixed to the outer periphery of the spring cover 370, so that the hook portion 206b is engaged with a notch 381 provided in the ring 380. In this example, the spring cover 370 is fixed to the output hub 304 with bolts 390.

In addition, in each of the above embodiments, the coil spring 206
It is preferable that the notch portion where the holder is locked be subjected to hardening treatment such as induction hardening to improve wear resistance. In addition, a permanent magnet 173 was used as the return force of the armature, but
Instead of the magnet 173, a spring means such as a plate spring or a coil spring, or an elastic body such as rubber may be used.

(Effects of the Invention) (10) As explained below, according to the present invention, the coil spring is wound only around the cylindrical winding surface of the input rotor to transmit torque from the input rotor to the output hub. Because of this, it is possible to reduce the number of turns of the coil spring and increase its spring constant, which eliminates impactful connections and eliminates the spring getting stuck in the gap g as in the conventional structure. This has the great effect of significantly improving clutch durability.

Furthermore, by reducing the number of turns of the coil spring, it is possible to shorten the axial dimension of the clutch and reduce the weight, which is extremely useful in practice.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a conventional electromagnetic spring clutch, FIG. 2 is a longitudinal sectional view of an electromagnetic spring clutch showing an embodiment of the present invention, and FIG. 3 is a sectional view taken along the line A-A in FIG. 2. ,
4 is a side view taken in the direction of arrow B in FIG. 2, FIG. 5 is a longitudinal sectional view of an electromagnetic spring clutch showing another embodiment of the present invention, and FIG.
Figures (al is a perspective view of the coil spring in Figure 5, Figure 6 (bl is a perspective view of the spring cover in Figure 5, Figure 7 (
a) is a perspective view showing the assembled state of the coil spring and spring cover shown in FIG. 6(δ)(b), FIG. 7(b)
2 is a perspective view of a ring that is further assembled therein. 1... Input rotor, 1a... Cylindrical winding surface, ■b.
... Friction surface, 2... Excitation coil, 6.206... Coil spring, 6a, 206a, 6b, 206b-y
Tsuk part, 104... Driven shaft, 150... Armature, 170, 272, 370... Spring cover. Agent Patent Attorney Takashi Okabe JP-A-121326 (5) Figure 3 Figure 5 1d 21b 150151 1) Sero υ curse＾人deno? Figure 6 (@) Figure 7 (4) (b) (b)

Claims (1)

[Claims] An input rotor to which rotation is transmitted from a drive source, a friction surface formed on one end surface of this input rotor, and an armature installed opposite to the friction surface of this input rotor, when energized. an excitation coil that generates magnetic flux to attract the armature to the friction surface of the input rotor; an output hub coupled to the driven shaft; a cylindrical winding surface protruding from the friction surface of the input rotor; A spring cover fixed to the output hub, and a hook portion disposed on the outer periphery of the cylindrical winding surface, a hook portion at one end thereof being latched to the armature, and a hook portion at the other end being latched to the spring cover. An electromagnetic spring clutch characterized in that the coil spring is wound only around the cylindrical winding surface of the input rotor to transmit torque from the input rotor to the output hub. (1)