JPS5929149Y2 - Drive shaft for spring clutch - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a drive shaft for a spring clutch that transmits rotational force by the winding force of a coil spring.

Conventionally, this type of spring clutch is
As shown in the figure, the drive shaft 1 and the driven shaft 2 are connected by a clutch spring 330 with a winding force, and the rotational force cutoff cam 4 is inserted into the outer circumference of the clutch spring 3.

The end 3a of the clutch spring 3 on the drive shaft 1 side
is locked in the notch groove 4a at the end of the drive side 1 side of the rotational force cutoff cam 4, and the end 3b of the clutch spring 3 on the driven shaft 2 side
is locked in a locking groove 2a of the driven shaft 2, and a backstop cam 5 having an engaging groove 5a is fixed to the end of the driven shaft 2, and a stopper (not shown) is attached to the engaging groove 5a. ) is installed so that it can be freely engaged and detached from the direction perpendicular to the axis.

However, the drive shaft 1 of the above-mentioned conventional example is molded from a sintered crystal of metal powder or a cut product of solid metal powder, and has problems in that it requires a large number of processing steps, is expensive, and is heavy.

Incidentally, a gear or the like is provided on the rotating shaft 11 of the clutch, and it is desirable to integrate this with the drive shaft 1 to reduce the number of parts.

For this reason, plastic gears are used for gears with low rotational torque, but if they are integrated with the drive shaft, they cause severe wear at the meshing part with the clutch spring, and if you try to reduce the wear, you will not be able to transmit large rotational torque. There are drawbacks.

In other words, in a geared drive shaft molded only from plastic, the magnitude of rotational torque is determined by the frictional force between the clutch spring 3, drive shaft 1, and q! The factors include the coefficient of friction, the tightness of the clutch spring, the number of turns of the spring, etc.

Therefore, the friction coefficient of plastic is usually 0.05 to 0.30.
Therefore, in order to suppress the amount of wear to the same level as that of metal, it is necessary to use a material with a low coefficient of friction, otherwise the rotational torque will become small and the spring clutch 40 will no longer be able to perform its function.

If you try to obtain metal-like torque by increasing the number of turns of the spun clutch spring, the length of the clutch spring will not only become longer, requiring a larger space, but also the response speed when engaging and disengaging the clutch will be slower. It has drawbacks such as being slow.

This device was devised to avoid the above-mentioned drawbacks, and has a simple structure that effectively transmits the power of the drive shaft to the driven shaft via the clutch spring, reduces the amount of heat generated by friction, and reduces the amount of heat generated by the rotating parts. The present invention provides a drive shaft for a spring clutch, which aims to reduce noise and reduce the weight of the drive unit.

Hereinafter, one embodiment of this invention will be explained in detail based on FIGS. 3 and 4.

Figure 3 a. 4 is a perspective view and a sectional view showing a drive shaft 10 according to this invention, and a driven shaft 12 is attached to the rotating shaft 11 in FIG.
is fixed by a spring pin 13.

A drive shaft 10 is rotatably fitted loosely into the small rotating shaft 11, and the drive shaft 10 is locked by a snap ring 14 so as not to be pulled out in the axial direction.

Spring-wrapped portion 10a of the drive shaft 10 and driven shaft 12
, 12a, a clutch spring 15 wound in a coil shape is inserted into the clutch spring 15, and the rotational force cutoff cam 1 is connected to the outer periphery of the clutch spring 15 with a predetermined clearance.
6 is fitted.

A ratchet 116a whose tooth tips face in one direction is formed on the outer periphery of the rotational force cutoff cam 16, and a stopper 17 is detachably attached to the ratchet 116a from the outside.

The end of the clutch spring 15 on the driven shaft 12 side is fixed to the driven shaft 12 (it may not be fixed if necessary), while the end 15a of the clutch spring 15 on the drive shaft 10 side receives rotational force. It is locked in a notched groove 16b formed on the end face of the cut-off cam 16, and the rotational force of the drive shaft 100 is transmitted through the clutch spring 15 by the spring-wrapped portion 10a of the drive shaft 10 and the winding force of the Claratis 19 Fufu 150. It is configured to be transmitted to the driven shaft 12 together with the cutoff cam 16.

In the above configuration, the drive shaft 10 is molded from an engine ring plastic, for example, a resin such as fluororesin, molybdenum disulfide, or polybutylene terephthalate containing a predetermined amount of oil, polyether sulfon, polyacetal, etc. A cylindrical metal pipe 18 is integrally embedded in the outer peripheral portion of the winding portion 10a, and a drive gear 10b is integrally formed on the drive side.

The power transmitted to the drive gear 10b of the drive shaft 10 is rotated by the winding force of the metal pipe 18 and the Claratis 19, and is transmitted to the driven shaft 12 together with the force cutoff cam 16.

On the other hand, when the stopper 17 from the outside engages with the ratchet t16a formed on the outer periphery of the rotational force isolation cam 16, the rotation of the rotational force isolation cam 160 is stopped, and along with this, the winding force of the Claratis 19fufu 150 is released. The drive shaft 10 rotates freely on the rotating shaft 11, and power transmission is cut off.

As explained in detail above, the drive shaft for a spring clutch according to this invention is manufactured from a plastic molded product with a metal pipe integrally embedded in the spring-wound part, and the rotating shaft and drive shaft are connected to each other. There is no need to lubricate the rotating parts, and the amount of heat generated can be reduced even without lubrication.

Further, since the drive gear of the drive shaft is made of plastic, it is possible to reduce meshing noise and noise between the drive shaft and the rotating shaft during idling, and it also has practical effects such as reducing power consumption.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing a conventional spring clutch, Fig. 2 is a vertical cross-sectional view of the same when assembled, Fig. 3 is a perspective view and cross-sectional view of the drive shaft according to this invention, Fig. 4 is a vertical cross-sectional view when assembled according to this invention. 10... Drive shaft, 10a... Spring wrapping part 10b... Drive gear, 11...
・Rotating axis, 12... Driven axis, 15...
Clutch spring, 16...Rotational force cutoff cam 18...Metal pipe.

Claims (1)

[Scope of utility model registration request] A clutch spring is wound around the spring-wrapped portions of the drive shaft and driven shaft, a rotational force cutoff cam is fitted to the outer periphery of this clutch spring, and the driven shaft side end of the clutch spring is used to drive the driven shaft! The I end is engaged with the end face of the rotational force cutoff cam, and the spring clutch transmits rotational force by the winding force of the clutch spring.
The drive shaft for a spring clutch is characterized in that the drive shaft is molded from engineering plastic with a cylindrical metal pipe integrally embedded in the outer periphery of the spring-wound portion.