JPH0719266A - Centrifugal clutch - Google Patents

Abstract

PURPOSE:To prevent the generation of strike noise of a clutch shoe and to prevent levitation of a clutch shoe at a low speed area by a method wherein a press plate to press and energize the side in an axial direction of the clutch shoe is fixed on a drive shaft. CONSTITUTION:An engaging groove for a clutch shoe 41 is fitted in three cantilever pieces 39 in the shape of a square in cross section radially protruded from the outer periphery of a clutch box 33, and energized in a central direction by means of a resilient device 47 engaged with a notch groove 45 formed peripherally of the clutch shoe 41. A clutch drum 49 is fixed on a driven shaft 51 in the vicinity of the outer periphery of the clutch shoe 41. The clutch shoe 41 is supported between an annular flange part 55 protruded externally of the clutch box 33 and a press plate 57 fixed between the clutch box 33 and a seat metal 35. The press plate 57 is made of a resilient material and locked on a rotary shaft by means of a pin 61 protruded from the side of the clutch boss 33 and fixed to the clutch box 33 by means of a nut 37 and presses the side of the clutch shoe 41.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal clutch for operating and connecting or disconnecting the power of an engine of a small two-wheeled vehicle, agricultural equipment, etc., depending on the rotation speed.

[0002]

2. Description of the Related Art A conventional centrifugal clutch of this type is constructed, for example, as shown in FIGS. That is,
A clutch boss 3 is fixed to the tip of the drive shaft 1 via a washer 5 by a nut 7. Three support pieces 9 each having a rectangular cross section are radially projected on the outer periphery of the clutch boss 3, and the engagement grooves 13 of the clutch shoe 11 are fitted in the support pieces 9 so as to be slidable in the radial direction. Is axially urged by an annular ammunition (a coil spring 17 in this embodiment) that engages with a notch groove 15 formed in the circumferential direction on one side surface in the axial direction.

A clutch drum 19 having an inner meridian near the outer circumference of the clutch shoe 11 is fixedly provided on a driven shaft 21. The driven shaft 21 is rotatably supported on the outer periphery of the drive shaft 1 via a bearing 23. The clutch shoe 11 has an annular flange 25 integrally formed by projecting outward on one side surface of the clutch boss 3 and an opposite side surface.
It is rotatably supported between the clutch boss 3 and the washer 5 and a circular support plate 27 integrally fixed to the clutch boss 3. A gear 29 is formed on the outer periphery of the driven shaft 21.

[0004]

In the conventional structure, when the clutch is engaged, the clutch shoe vibrates and emits a tapping sound. In particular, when the throttle is operated with a grip such as a handle, it may be fixed at a rotational speed at which the tapping sound is easily generated, which may cause breakage of the clutch shoe and give an operator discomfort. Further, in a small-sized low-speed output type engine, the intervals between clutch engagement and disengagement rotation speeds are small, and the clutch shoe is easily lifted up.

[0005]

According to the present invention, a holding plate for pressing and urging the side surface of the clutch shoe in the axial direction to impart a resistance force to the movement of the clutch shoe is fixed to the drive shaft.

[0006]

When the drive shaft rotates and exceeds a predetermined rotation speed, the clutch shoe moves in the radial direction against the ammunition by the centrifugal force and abuts against the inner surface of the clutch drum to press the clutch drum to the clutch. The power of the drive shaft is transmitted to the driven shaft by rotating with the shoe, and when the rotational speed is reduced, the clutch shoe is separated from the clutch drum by the bullet and the power is shut off. When the clutch shoe connects,
When the clutch shoe is about to vibrate, the sliding resistance due to the frictional force between the pressing plate and the clutch shoe prevents the vibration and prevents the generation of hammering noise.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 3, the clutch boss 33 is fixed to the tip of the drive shaft 31 by a nut 37 via a washer 35. Three support pieces 39 each having a square cross section are radially projected on the outer periphery of the clutch boss 33, and the engagement grooves 43 of the clutch shoe 41 are fitted in the support pieces 39 so as to be slidable in the radial direction. It is urged toward the center by an annular ammunition machine (a coil spring in this embodiment) 47 that engages with a notch groove 45 formed in the circumferential direction on one side surface in the axial direction.

A clutch drum 49 having an inner diameter hole near the outer circumference of the clutch shoe 41 is fixedly provided on the driven shaft 51. The driven shaft 51 is rotatably supported on the outer periphery of the drive shaft 31 via a bearing 53. The clutch shoe 41 is integrally fixed to the clutch boss 33 between the clutch boss 33 and the washer 35 on the opposite side surface and the annular flange 55 integrally formed on one side surface of the clutch boss 33 so as to project outward. It is rotatably supported between the pressing plate 57 and the pressing plate 57. A gear 59 is formed on the outer periphery of the driven shaft 51. The holding plate 57 is made of an elastic material such as a steel plate, and has a pin 61 protruding to the side surface of the clutch boss 33.
, Is fixed to the clutch boss 33 by the nut 37, and is biased to press the side surface of the clutch shoe 41 by the radially formed bullet portion 63.

When the drive shaft 31 rotates to a speed equal to or higher than a predetermined rotation speed, the clutch shoe 41 is caused by centrifugal force to cause the ammunition 4 to move.
It moves in the radial direction against 7 and contacts and presses against the inner surface of the clutch drum 49, and the clutch drum 49 rotates together with the clutch shoe 41.
1 is transmitted. When the rotation speed decreases, the clutch shoe 41 is disengaged from the inner surface of the clutch drum 49 by the bullet 47, and the power is shut off. When the clutch shoe 41 is connected, if vibration is about to occur, the sliding resistance is prevented by the sliding resistance due to the frictional force between the pressing plate 57 and the clutch shoe 41, and the generation of hammering sound is prevented.

4 to 6 show another embodiment, in which the pressing plate 57 is formed of a normal steel plate in a circular shape, and an annular guide plate 65 and an annular corrugated spring are formed between the pressing plate 57 and the side surface of the clutch shoe 41. The washer 67 is sandwiched and is urged to press the clutch shoe 41. 4 to 6, the same reference numerals as those shown in FIGS. 1 to 3 above represent the same components.

In this embodiment, the clutch shoe is provided so as to be engaged with the engaging groove of the clutch boss and slidable in the radial direction, but the present invention is not limited to this structure. For example, one end of the clutch shoe in the circumferential direction may be pivotally attached to the clutch boss so as to be swingable in the radial direction.

[0012]

According to the present invention, the hitting sound of the clutch shoe can be eliminated, the lifting of the clutch shoe can be prevented in the low speed range, the weight can be reduced, and the overall size can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of the present invention.

FIG. 2 is a side sectional view of the same.

FIG. 3 is a side sectional view taken along line III-III of the same FIG.

FIG. 4 is a side sectional view of another embodiment.

FIG. 5 is a front view of the same.

6A is a front view of a spring washer, and FIG. 6B is a developed side view of the spring washer.

FIG. 7 is a front view of a conventional example.

FIG. 8 is a side sectional view of the same.

9 is a front sectional view taken along line XI-XI of FIG.

[Explanation of symbols]

 31 Drive Shaft 33 Clutch Boss 41 Clutch Shoe 47 Bullet Machine 49 Clutch Drum 51 Driven Shaft 57 Presser Plate 67 Spring Washer

Claims (3)

[Claims] 1. A clutch boss 33 fixed to a drive shaft 31.
A plurality of clutch shoes 41 movably supported in the radial direction and locked in the circumferential direction, and fixed to a driven shaft 51 provided coaxially with the drive shaft 31 on the clutch shoe 41. In the centrifugal clutch provided with a clutch drum 49 having an inner diameter surface capable of contacting with the outer periphery of the clutch shoe 41 and provided with an ammunition 47 for urging the clutch shoe 41 in the central direction, a side surface on the axial side of the clutch shoe 41 is A centrifugal clutch characterized in that a pressing plate 57 for pressing and urging to give a resistance force to the movement of the clutch shoe 41 is fixedly provided to the drive shaft 31. 2. The centrifugal clutch according to claim 1, wherein a bullet portion is formed on a part of the pressing plate 57 made of an elastic material. 3. The centrifugal clutch according to claim 1, wherein an annular spring washer 67 is interposed between the pressing plate 57 and the clutch shoe 41.