JPS631062Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a power transmission device equipped with a safety mechanism against overload.

In a power transmission device in which two rotating shafts are connected by a universal joint, overload generation is required to prevent damage to the power transmission medium such as the machine body and the universal joint due to accidental overload (torsion torque). By 2
A safety mechanism is often used that allows the two rotating shafts to be uncoupled.

The slip clutch method and the shear pin disconnection method are conventionally well-known safety mechanisms against overload in power transmission devices, but the former slip clutch method has a complicated structure and is expensive.
In addition, there is a drawback that the outer diameter is larger than that of the mounting shaft, resulting in an increase in the size of the device. In addition, with the latter shear pin cutting method, smooth idling cannot be obtained due to the deformation of the fractured surface after the pin is cut, and there is a high risk that the machine will become locked and the power transmission medium such as the universal joint will be destroyed, and the shear pin , so restoration requires a new shear pin and a large amount of restoration work.

In view of the above-mentioned drawbacks of the conventional technology, this invention improves and eliminates them, and has a compact structure, does not damage the power transmission medium such as the machine body and universal joints, and is capable of instantaneous restoration of power. This is a power transmission device equipped with a safety mechanism against overload in the transmission device, and its configuration is such that in a power transmission device in which two rotating shafts are connected by an intermediate shaft via a universal joint, the intermediate shaft A is A first shaft member B having
and a second shaft member C that fits into the cavity and is always pressed against the bottom surface of the cavity, and the first shaft member B has a protrusion D on the bottom surface of the cavity and a second shaft member C on the inner peripheral surface. The first annular groove 4 and the chamfered portion 5 are formed on the periphery of the opening, and the opening side wall surface of the first annular groove 4 is made an inclined surface, and the first shaft member C is formed on the distal end surface of the second shaft member C. A V-groove 7 that engages with the protrusion D of member B and a second annular groove 8 that mounts the snap spring 9 on the outer peripheral surface are formed, respectively, and the fitted state of the first and second shaft members B and C is formed. In this embodiment, the protrusion D and the V-groove 7 are engaged with each other, and the snap ring 9 is expanded in diameter so as to straddle the first and second annular grooves 4 and 8.

An embodiment of this invention will be described below with reference to the following.

FIG. 1 is a partial side sectional view showing an embodiment of this invention using a tri-ball universal joint. In the figure, 1 is a universal joint connected to a rotating shaft (not shown) of a drive unit, and a boss portion 1a is a first shaft member B, a pin 3 is integrally attached to a semicircular groove 2 formed on the bottom surface of the cavity of this boss portion 1a to form a protrusion D, and a side wall on the cavity opening side is attached to the inner peripheral surface of the cavity. Slanted first annular groove 4
A chamfered portion 5 is formed on the periphery of the cavity opening. 6 has a V groove 7 on the tip surface and a second annular groove 8 on the outer peripheral surface near the tip.
This spline shaft 6 is a second shaft member C. Then, the snap ring 9 is engaged with the second annular groove 8 in advance, and then the diameter of the snap ring 9 is reduced and the snap ring 9 is positioned concentrically. It is fitted in the axial direction to a position where it also engages with the first annular groove 4 on the inner circumferential surface of the cavity of the portion 1a, and the pin 3 is engaged in the V groove 7 on the distal end surface to couple with the universal joint 1. In short, the first and second shaft members B and C constitute the intermediate shaft A. 10
is a spline sleeve connected to a rotating shaft (not shown) of the driven part via a universal joint 11, and is spline-fitted with the spline shaft 6 to transmit the rotation of the driving part to the driven part. , absorbs relative movement between the driving part and the driven part.

By the way, the appropriate torque is determined by the diameter d ₁ of the pin 3, the diameter d ₂ of the spline shaft 6, and the diameter of the snap spring 9.
d ₃ and the oblique angle (θ) of the inclined wall surface of the first annular groove 4
It can be set by etc. In addition, the boss part 1
The protrusion amount a of the pin 3 with respect to the bottom surface of the cavity of
is designed to be larger than the length b from the center of the annular groove 4 to the small diameter side of the chamfered part 5, and when the boss part 1a and the spline shaft 6 are fitted, the pin 3 of the boss part 1a and the V of the spline shaft 6 When the groove 7 is disengaged, the snap spring 9 is automatically popped out.

According to this embodiment of the invention having the above configuration, under normal load, as shown in FIGS. 1 and 2, the torque of the drive unit is generated between the pin 3 of the universal joint 1 and the V-groove 7 on the end surface of the spline shaft 6. Due to the engagement, the transmission is transmitted to the spline shaft 6 via the universal joint 1, and further, due to the spline fitting between the spline shaft 6 and the spline sleeve 10, the transmission is transmitted to the spline sleeve 1.
0, torque is transmitted to the driven part via the universal joint 11. Next, if an overload exceeding the proper transmission torque is applied due to the occurrence of abnormal torque, etc., the spline shaft 6 will not connect to the pin 3 because the V groove 7 on the tip surface engages with the pin 3 in Fig. 5. 3 is disengaged, i.e., in the direction of the arrow in the figure, the hollow inner circumferential surface of the boss portion 1a of the universal joint 1 and the outer circumferential surface near the tip of the spline shaft 1 are formed. The diameter of the snap ring 9 that is engaged with the first and second annular grooves 4 and 8 is reduced by the inclined wall surface of the first annular groove 4 and fits into the second annular groove 8, so that the spline shaft 6 is When the spline shaft 6 moves in the direction of the arrow as shown in the figure and further moves as shown in FIG. 6 until the snap spring 9 is positioned on the chamfered portion 5 of the cavity opening periphery of the boss portion 1a of the universal joint 1, The engagement between the pin 3 and the V-groove 7 on the tip surface of the spline shaft 6 is disengaged, causing the spline shaft 6 to rotate idly, and the connection between the driving part and the driven part to be broken, which prevents damage to the machine body and the universal joints 1 and 11. is prevented. Next, in order to restore the power transmission device, the spline shaft 6 may be pushed into the cavity of the boss portion 1a.
That is, in connection with the pushing operation of the spline shaft 6, the diameter of the snap spring 9 is reduced by the chamfered portion 5 of the opening periphery of the boss portion 1a, and after the snap spring 9 and the spline shaft 6 are positioned concentrically, the universal joint is The spline shaft 6 is fitted into the cavity of the first boss part 1a in the axial direction to a position where the snap spring 9 also expands in diameter and engages with the first annular groove 4 on the inner peripheral surface of the cavity of the boss part 1a. Accordingly, it is possible to restore the state shown in FIGS. 1 and 2. In addition, in the figure, 12 is a spring for preventing falling off.

In the above description, an embodiment has been described in which a tri-ball universal joint is used and the boss portion is the first shaft member, but the invention is not limited to this embodiment. For example, the first shaft member may be connected to the boss portion of the tri-ball universal joint by any suitable means.

As explained above, this invention is a power transmission device in which two rotating shafts are connected by an intermediate shaft via a universal joint, in which the intermediate shaft is fitted into a first shaft member having a cavity, and the intermediate shaft is fitted into the cavity. and a second shaft member that is always pressed against the bottom surface of the cavity, and the first shaft member is
A protrusion is formed on the hollow bottom surface of the shaft member, a first annular groove is formed on the inner peripheral surface, and a chamfer is formed on the opening periphery, and the opening side wall surface of the first annular groove is an inclined surface, and the second A V-groove that engages with the protrusion of the first shaft member and a second annular groove for mounting a snap spring on the outer circumferential surface are respectively formed on the distal end surface of the shaft member, and the first and second shafts are connected to each other. In the fitted state of the member, the protrusion and the V groove are engaged, and the amount of axial engagement between the protrusion and the V groove is greater than the axial length from the first annular groove to the chamfered portion. Since the diameter of the snap spring is expanded so that it straddles the first and second annular grooves, even if the drive part and driven part are disconnected in the event of an overload, the power transmission media such as the machine body and universal joint will remain intact. It has the advantage that it does not cause any damage, can be restored instantly, and has a simple, compact structure and can be obtained at low cost, making it very practical.

[Brief explanation of drawings]

Fig. 1 is a partial side sectional view showing an embodiment of the overload safety mechanism in the power transmission device of this invention, Fig. 2 is an enlarged sectional view of the main part thereof, and Fig. 3 is a sectional perspective view of the main part. , FIG. 4 is an exploded view of the main part, and FIGS. 5 and 6 are sectional views of the main part showing the operating state at the time of overload. A... Intermediate shaft, B... First shaft member, C... Second shaft member, D... Projection, 1, 11... Universal joint, 4... First annular groove, 5... Chamfered portion, 7...
...V groove, 8...Second annular groove, 9...Snat spring.

Claims (1)

[Scope of utility model registration request] In a power transmission device in which two rotating shafts are connected by an intermediate shaft via a universal joint, the intermediate shaft is connected to a first shaft member having a cavity, and the intermediate shaft is fitted into the cavity and is constantly pressed against the bottom surface of the cavity. a second shaft member, and a protrusion on the bottom of the cavity of the first shaft member;
A first annular groove is formed on the inner peripheral surface and a chamfered portion is formed on the opening periphery, the opening side wall surface of the first annular groove is an inclined surface, and the first annular groove is formed on the distal end surface of the second shaft member. A V groove that engages with the protrusion of the shaft member and a second annular groove into which the snap spring is fitted are formed on the outer circumferential surface, and when the first and second shaft members are in the fitted state, the protrusion and the V groove, and the axial engagement amount between the protrusion and the V groove is made larger than the axial length from the first annular groove to the chamfered part, and the first
A power transmission device equipped with a safety mechanism against overload, characterized in that the diameter of the snap spring is expanded so as to straddle the second annular groove.