JPS6327583B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electromagnetic spring clutch coupled between a rotating machine and a prime mover for intermittently driving a refrigerant compressor of an automobile air conditioner, etc. It is related to.

Conventional structure and its problems The conventional general electromagnetic spring clutch is
As shown in the figure, an annular excitation coil 2 fixed to a fixed frame is disposed inside an input hub 3 that rotates and is mounted on a bearing 1. A plurality of arc-shaped through holes 4 are bored in the hole. 5 is an output hub fixedly mounted on the output shaft 6 facing the input hub 3, and 7 is an armature plate provided for the through hole 4, which rotates on the same axis as the output hub 5. The spring holding drum 8 is rotatably and slidably held in contact with the flange portion 9 of the spring holding drum 8 fixed to the output hub 5 as shown in FIG. Reference numeral 10 denotes a coil spring formed into a coil shape, which is wound around the spring holding drum 8. An outward hook 11 bent outward is provided at the beginning of winding of the coil spring 10, and an inward hook 12 bent inward is provided at the end of winding. This coil spring 10 is connected to the winding surface 1 of the input hub 3.
3, and is fitted to the armature plate 7 on the outside of the winding surface 14 of the output hub 5, and the outward hook 11 is engaged in the hook insertion hole 15 of the armature plate 7, and the inward hook 12 is fitted into the armature plate 7. It is inserted into the hook insertion hole 16 of the output hub 5 via a loose body 17 that can be displaced in the torque transmission direction.

In the conventional electromagnetic spring clutch configured as described above, when the excitation coil 2 is excited, the armature plate 7 is attracted by the excitation coil 2 and rotates together with the input hub 3, and at the same time the armature plate 7 is rotated. The outward hook 11 of the coil spring 10 inserted into the insertion hole 15 also rotates.
Therefore, the coil spring 10 tightens the winding surfaces 13 and 14 of the input hub 3 and the output hub 5 to transmit rotational force from the input hub 3 to the output hub 5. At that time, the rotational force is rapidly transmitted, but this rotational force cannot be transmitted only between the output hub 5 and the coil spring 10, and the coil spring 10
The signal is transmitted from the inward hook 12 to the output hub 5 via the buffer 17. However, since the shock absorber 17 is compressed and displaced in response to this transmitted force and the load of the refrigerant compressor, etc., slippage occurs between the output hub 5 and the coil spring 10, and the sudden transmission of rotational force is relaxed and transmitted. .

When the excitation coil 2 is de-energized, the attracted armature plate 7 separates from the input hub 3, and the coil spring 10 expands to create a gap between it and the wound surface 13 of the input hub 3, cutting off the rotational force. be.

However, in the above configuration, since a concave groove is provided on the outer periphery of the output hub 5 that frictionally engages with the coil spring 10, this groove cannot be made large, and therefore, it is not possible to make the groove large. When the coil spring 10 is wound due to this concave groove, the shock absorbing effect is limited.
This coil spring 10 is deformed and has a problem of poor sliding with the output hub, impeding the buffering effect.

OBJECTS OF THE INVENTION In view of the above-mentioned problems, the present invention provides an electromagnetic spring clutch that increases displacement in the torque transmission direction and has a large damping effect without the adverse effects of concave grooves and the like.

Composition of the Invention The present invention has shaft-side friction surfaces provided on the outside of an input hub and an output hub body, and within the shaft-side friction surfaces, one end is locked to the armature body and the other end is fixed to the armature body. It consists of a coil spring that contacts and locks the protruding part of the output hub body via a buffer body, and an excitation coil that attracts the armature body to the input hub.The coil spring is expanded through the armature body by excitation of the excitation coil. A coil spring is pressed against each of the friction surfaces on the shaft center side to transmit rotational force from the input hub to the output body, and the transmission of rotational force is alleviated in the same manner as in the conventional example. No concave groove is formed on the shaft-side friction surface of the output hub body, and the size of the buffer in the torque transmission direction is not limited by the size of the concave groove, so it is configured to be large in that direction. This has the unique effect of increasing the buffering effect.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. FIG. 3 is a cross section of an electromagnetic spring clutch in one embodiment of the present invention, and the fourth
The figure is a cross-sectional view taken along the line AA shown in FIG. 3.
21 is a small screw 2 attached to the fixed frame 22 of the refrigerant compressor.
3 is an annular excitation coil fixedly installed, and 24 is an input hub rotatably attached to the fixed frame 22 via a bearing 25, and also fixed in the axial direction by upper rings 26 and 27. The hub 24 is provided with a V-groove 28 and is connected to a drive shaft pulley of an engine (not shown) by a V-belt (not shown). Further, a cylindrical shaft-side friction surface 29 is provided at the outer end of the input hub 24, and a plurality of arc-shaped through holes 31 are bored in the inner end surface 30 thereof. Reference numeral 32 denotes an output hub body, which is fixed to the output shaft 33 of the refrigerant compressor with bolts 34. The input hub 24 is attached to the outer cylindrical portion of the output hub body 32.
A shaft-side friction surface 35 is provided with approximately the same diameter as the shaft-side friction surface 29 of
6 is provided. Reference numeral 37 denotes an armature body having a protruding portion 38 on a part thereof, and this armature body 37 is fitted into the stepped portion of the output hub body 32.
It is rotatable and can also be slid in the axial direction. 3
Reference numeral 9 denotes a coil spring formed into a coil shape so as to be unwound with respect to the rotational direction of the input hub 24. An end surface 40 of this coil spring 39 at the beginning of winding abuts on the protrusion 37, and an end surface 40 at the end of winding. end face 4
1 are in contact with each other via a buffer 42. The coil spring 39 is wound on the outer circumferential surface of the armature body 37 and a part of the output hub body 32, with a gap provided between the shaft center side friction surfaces 29 and 35.

The operation of the excitation spring clutch constructed as described above will be explained below. The input hub 24 rotates via a bearing 25 because a V-groove 28 provided in the input hub 24 and a driving pulley of an engine (not shown) are connected by a V-belt (not shown). When the exciting coil 21 is not excited, the armature body 37 is pulled away from the end surface 30 of the rotating input hub 24 by the force of a weak spring (not shown) or the like. Further, the coil spring 39 is wound around the outer peripheral surface of the armature body 37 and a part of the output hub body 32,
A slight gap is formed between the shaft center side friction surfaces 29 and 35. Therefore, no rotational force is transmitted to the output hub body 32, and the output shaft 33 is not driven.

When the excitation coil 21 is excited, a magnetic circuit shown by the broken line in FIG. 3 is generated, and the armature body 37 is attracted to the end surface 30 of the input hub 24 and frictionally engaged therewith. Therefore, the armature body 37 rotates together with the input hub 24. Therefore, the protrusion 38 provided on the armature body 37 and the winding start end surface 40 of the coil spring 39 that is in contact with the protrusion 38 rotate in the direction in which the coil spring 39 is unwound. However, the winding end surface 41 of the coil spring 39 is connected to the output hub body 3 through the buffer body 42.
At this time, the output hub body 32 is not yet rotated due to the load of the refrigerant compressor or the like. Moreover, the buffer body 42 is also only slightly deformed. Next, armature body 3
7 rotates, the coil spring 39 receives a rotational force from the protruding portion 38 provided on the armature body 37 in the direction in which the winding start end surface 40 is unwound, so that the coil spring 39 expands and causes the shaft center side friction surfaces 29, 35 to Pressure contact. At this time, the outer circumferential surface of the coil spring 39, the axial friction surface 29 of the input hub 24, and the axial friction surface 35 of the output hub body 32 are frictionally engaged with each other, and the rotational force of the input hub 24 is transferred to the output hub body 32. However, this rotational force cannot be fully transmitted only between the output hub body 24 and the coil spring 39, and the output hub is provided with a protrusion 36 from the end surface 41 of the coil spring 39 via a buffer body 42. transmitted to the body 32. However, since the buffer body 42 contracts and displaces in response to this transmitted force and the load of the refrigerant compressor, etc., slippage occurs between the shaft-side friction surface 35 of the output hub body 32 and the outer peripheral surface of the coil spring 39, causing sudden The transmission of rotational force is performed in a relaxed manner.

When the excitation coil 21 is de-energized, the armature body 37 is separated from the end face 30 of the input hub 24 due to the force of a weak spring (not shown), and the coil spring 39 is moved away from the end face 30 of the input hub 24 due to the return force of the coil spring 39, which tends to reduce the winding diameter. , against the centrifugal force, etc., and is separated from the shaft center side friction surfaces 29, 35, and is wound around the outer circumferential surface of the armature body 37 and a part of the output hub body 32 at the original position. The buffer body 42 also returns to its original size. Therefore, transmission of rotational force is interrupted. The above operation is repeated.

As described above, according to this embodiment, the coil spring 3
A buffer is inserted between the end 41 of the output hub 32 and the protrusion 36 of the output hub 32, so that the coil spring 39 and the output hub 32 are engaged with each other via the buffer 42. Therefore, there is no concave groove on the axial friction surface 35, which is the frictional engagement surface between the outer peripheral surface of the coil spring 39 and the output hub body 32, and therefore, even if the coil spring 39 is pressed against the coil spring 39, the coil spring 39 will not be deformed. Therefore, as described above, smooth sliding occurs between the outer circumferential surface of the coil spring 39 and the shaft center side friction surface 35 of the output hub body 32 in response to the contraction displacement of the buffer body 42 during rotational force transmission. Further, the size of the buffer body 42 in the rotational force transmission direction can be configured to be sufficiently large.

Effects of the Invention As described above, according to the present invention, a buffer is inserted between the end of the coil spring and the protrusion of the output hub, and the coil spring and the output hub are connected to each other through the buffer. By configuring it to be locked, it is possible to increase the effect of alleviating the sudden transmission of rotational force from the input hub to the output hub body, and this has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional electromagnetic spring clutch, FIG. 2 is a side view of the main part of the engagement portion between the end of the coil spring and the hub in FIG. 1, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a sectional view taken along line A--A shown in FIG. 3. 21... Excitation coil, 24... Input hub, 32
...Output hub body, 35...Axis-side friction surface of output hub body, 36...Protrusion of output hub body, 37...Amateur body, 39...Coil spring, 41...Coil spring end, 42 ...Buffer.

Claims (1)

[Claims] 1. An annular excitation coil fixed to a fixed frame, an input hub that attracts the armature body by excitation of the excitation coil, and an output hub body that rotates on the same axis as the rotation axis of the input hub. , a coil spring having one end fixed to the armature body and the other end fixed to the output hub body; and the cylinder of the input hub, which is located outside the coil spring and faces the coil spring, forming an axial-side friction surface. and a cylindrical portion of the output hub body forming an axial friction surface with approximately the same diameter as the axial friction surface, and an end portion of the coil spring on the side that is locked to the output hub body. and an electromagnetic spring clutch configured such that a shock absorber is inserted between the protrusion provided on the output hub body and the coil spring and the output hub body are engaged with each other via the shock absorber.