JPS5810021Y2 - electromagnetic spring clutch - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to improvements in electromagnetic spring clutches.

Generally, in an electromagnetic spring clutch, a part of the input hub side and a part of the output hub side are used as coil spring wrapping surfaces, one end of this coil spring is fixed to the output hub side, and the other end is attached concentrically to the coil spring. It has a structure in which it is locked to the excitation coil side of an armature that is slidably supported by the armature.

FIG. 1 shows a sectional view of an electromagnetic spring clutch that has been widely used in the past.

In the same figure, an annular excitation coil 3 fixed to a fixed frame F is fitted inside an input hub 2 which is rotatably mounted on a bearing 1a, and a plurality of annular excitation coils 3 are fixed on a side surface of the human-powered hub 2. Arc-shaped through holes 4 are bored.

Reference numeral 5 denotes an output hub provided on the same rotational axis as the input hub 2, and the output hub 5 is pivotally attached to an output shaft 6 that is pivotally supported by a fixed frame F via a bearing 1b.

Reference numeral 7 denotes an armature whose flange side surface is in contact with the through hole 4, and is connected to the output hubs 2 and 5 via a coil spring, which will be described later.

Reference numeral 8 denotes a coil spring formed in the form of a coil, and as shown in FIG. 2, an outward hook 9 is provided at one end of the spring and bent outward, and an outward hook 9 is bent inward at the end of winding. An inward hook 10 is provided.

This coil spring 8 is connected to the winding surface 11 of the input hub 2.
and is interposed between the winding surface 12 of the output hub 5 and the cylindrical portion of the armature 7, and the outward hook 9 is engaged in the hook insertion hole 13 of the armature 7,
Further, both ends of the inward hook 10 are locked by being engaged with the hook engaging hole 14 of the output hub 5.

FIG. 3 is a rear view of the armature 7, and 13 is a hook insertion hole provided on the inner circumferential surface of one open end thereof.

In the conventional spring clutch configured as described above, when the excitation coil 3 is excited, the armature 7 is attracted to the excitation coil 3 and rotates together with the human-powered hub 2, and at the same time, the armature 7 is inserted into the hook insertion hole 13 of the armature 7. The outward hook 9 of the engaged coil spring 8 also rotates.

Therefore, the inward hook 10 of this coil spring 8
is engaged in the hook engagement hole 14 of the output hub 5, so
As the coil spring 8 tightens the respective coiled surfaces 11, 12 of the input hub 2 and the output hub 5, the output hub 5 also rotates.

In other words, the rotational force applied to the input hub 2 is transferred to the output hub 5.
Rotation is transmitted to.

When the excitation coil 3 is de-energized, the attracted armature 7 separates from the input hub 2, and the coil spring 8
expands to create a gap with the winding surface 11 of the input hub 2 and cut off rotational transmission.

However, in such a conventional spring clutch, the armature 7 has a flange portion 7a that is attracted to the input hub 2 and a cylindrical portion 7 that covers the coil spring 8.
Since the coil spring 8 is formed from the coil spring 8, it is heavy and therefore has a large inertia, which causes the coil spring 8 to act in the opposite direction to its return direction when deenergized, resulting in a problem that the clutch becomes difficult to disengage. .

In addition, the coil spring storage part is always in communication with the outside, such that there is a gap between the input hub 2 and the flange 73 when it is not energized, and between the end surface of the cylindrical part 7b and the output hub 5 when it is energized. Therefore, there is also a drawback that dust easily enters the storage section, which makes the operation of the armature 7 unsmooth.

Such a problem is particularly noticeable in a structure in which there is a gap between the armature 7 and the coil spring 8 as shown in FIG.

In addition, in the de-energized state, the armature 7 is connected via the coil spring 8 to the winding surfaces 11 and 12 of the input/output hub.
It is simply supported with a loose fit, and has the disadvantage that it vibrates and generates noise.

The present invention solves these drawbacks by forming the armature into an annular shape, and loading this annular armature into the annular guide portion of a holder fixed to the output hub so that it can slide and rotate freely. This provides an electromagnetic spring clutch that operates quickly and smoothly with an extremely simple configuration.

Hereinafter, the configuration and the like will be explained in detail with reference to embodiments shown in the drawings.

FIG. 4 shows a longitudinal sectional side view of the electromagnetic spring clutch according to the present invention.

In this figure, the same members as in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted.

In the same figure, the reference numeral 15 indicates an annular armature, and a hook insertion hole 13 into which the outward hook 9 of the coil spring 8 engages is provided in a part of the inner peripheral surface of the annular armature. is held so as to face the side surface of the input hub 2 by a cylindrical holding body 16, which will be described later.

As shown in the figure, this holder 16 includes a cylindrical portion 16a that holds the coil spring 8, an inward flange portion 16b that is fixed to the output hub 5, a flange portion 16c that supports the annular armature 15 in the axial direction, and a cylindrical portion 16a that holds the coil spring 8. It is formed from an annular guide portion 16d projecting from the periphery of the flange portion 16c toward the input hub 2 side.

The annular armature 15 is held in a rotatable and slidable manner by being loaded into the annular guide portion 16d.

On the other hand, a coil spring 8 is interposed between this holding body 16 and the winding surfaces 11.12 of the input/output hubs 2 and 5, and the outer peripheral surface of this coil spring 8 is It is press-fitted into pressure contact with the inner circumferential surface of the body 16.

That is, the outer diameter of the coil spring 8 under no load is formed to be somewhat larger than the inner diameter of the holder 16, and the coil spring 8 is loaded into the holder 16 with a load applied in the tightening direction.

To explain the operation of the spring clutch according to the present invention configured as above, first, when the excitation coil 3 is excited, a magnetic path bypassing the through hole 4 is formed as shown by the broken line in the figure, and the annular armature 15 is attracted. do.

Therefore, the coil spring 8 tightens the coiled tightening surface 11 of the input hub 2 and also tightens the coiled tightening surface 12 of the output hub 5, so the rotational force of the input hub 2 is rotationally transmitted to the output hub 5, and the output hub Rotate.

On the other hand, when the excitation coil 3 is de-energized, the annular armature 15 that was attracted to the excitation coil 3 separates from the input hub 2, and therefore the tightening between the coil spring 8 and the tightening surface 11 of the input hub 2 becomes loose. I'm about to try.

At this time, in addition to the elastic force accumulated when the coil spring 8 is loaded into the holding body 16, the elastic force is further increased by the above-mentioned tightening operation, so that the moment the coil spring 8 is released from the tightening operation, It rebounds and spreads out, and is separated from the winding surfaces 11 and 12 of the input hub 2 and output hub 5, and the transmission of rotational force is cut off.

As explained above, according to the present invention, the holding body that holds the coil spring and the annular armature are separated, so the armature is lightweight, so the inertia that acts when deenergized is also small, and rotation transmission is interrupted. can be done quickly.

In addition, since the holder that holds the coil spring is fixed to the output hub, the gap between the spring housing and the outside is smaller compared to conventional ones, and there is less dust entering the housing. .

In particular, if the structure is such that the coil spring is brought into close contact with the circumferential surface of the holder as shown in the example, the influence of dust will be reduced, and the annular guide portion of the holder may be extended so that its end surface is close to the side surface of the input hub. This will further reduce the intrusion of dust.

Furthermore, since the annular armature and the coil spring are movably held by a holder fixed to the output huff, it can be expected to have the effect of eliminating noise caused by vibrations, etc.

[Brief explanation of the drawing]

Figures 1 to 3 show a conventional electromagnetic spring clutch, with Figure 1 being a longitudinal side view, Figure 2 being a front view of the coil spring, Figure 3 being a rear view of the armature, and Figure 4 being the present invention. It is a longitudinal side view of the electromagnetic spring clutch concerning this. 2...Human power hub, 3...Excitation coil,
5... Output hub, 8... Coil spring, 15... Annular armature, 16...
... Holding body, 16d... Annular guide part.

Claims (1)

[Scope of utility model registration request] An annular excitation coil 3 fixedly installed on a fixed frame F, an annular armature 15, an input hub 2 that attracts the annular armature 15 by excitation of the excitation coil 3, and a rotational axis and an axis of rotation of this input hub 2. A coil spring 8 is provided so as to surround the output hub 5 which rotates thereon, and the winding surfaces 11, 12 of both hubs 2.degree. and a cylindrical holder 16 that is fixedly attached to the output hub 5 and holds the coil spring 8 and the annular armature 15. An electromagnetic spring clutch is provided with an annular guide portion 16d for slidingly and rotatably holding the inside of the electromagnetic spring clutch.