JPH0225057B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention connects an input side member and an output side member by pressing a steel ball into a concave hole with a spring material to transmit rotational power. When an excessive load is applied to
This prevents the steel balls from escaping from the recessed holes due to the pressing force of the spring material, preventing damage to the power transmission system equipment due to overload. The present invention relates to a torque releaser that has stable performance without degrading the initial function of the torque releaser even if the transfer operation is repeated.

<Conventional technology> Conventional torque releasers that use steel balls for power transmission use a tapered hole into which the steel ball enters during power transmission, and the steel ball escapes from the hole during overload. The rolling trajectory of the steel ball up to the next recessed hole was made into a flat surface, but some improvements have been made in recent years, such as making the recessed hole a spherical seat with the same radius as the steel ball, and making the rolling trajectory of the steel ball flat. A groove with the same radius as the steel ball or a value close to it is provided on the dynamic trajectory surface like a thrust bearing.
Measures have been taken to extend the life of the steel ball and its opposing surface by changing the point contact between the steel ball and its opposing surface to line contact, and the line contact to area contact. .

<Problem to be solved by the invention> The torque reliever improved as described above has the following problems:
When the steel ball is rolled in, the steel ball and the concave hole into which the steel ball is inserted have the same radius, resulting in surface contact, and on the rolling trajectory of the steel ball, they are in a groove with the same radius as the steel ball, so they are in line contact, which has been improved.

However, the connecting portion between the rolling trajectory surface of the steel ball and the recessed hole into which the steel ball is transferred is a point contact, and is a sharp angular surface.

When the steel ball rolls and enters the recess while being strongly pressed against the opposing surface by the spring force, the steel ball enters the recess while being pressed against the sharp angular surface.

Furthermore, when the steel ball entry speed is high, the steel ball collides with the sharp angular surface of the recessed hole on the steel ball escape side. Next, when the steel ball escapes from the recessed hole due to overload, the steel ball reaches the steel ball rolling surface while rolling on the sharp angular surface. By repeating these operations, the surface of the steel ball is scratched by the sharp corners, and the corners are crushed or missing. As a result, the roughness of the corners expands the scratches on the surface of the steel ball, causing the steel ball to become damaged. Scratches damage not only the corner surfaces, but also the steel ball rolling surfaces and the concave hole surfaces, significantly reducing the original function of the torque reliever and, in turn, significantly shortening its lifespan.

<Means for solving the problem> This invention was made to solve the problems of the conventional torque reliever as described above.
By making the corner of the connecting part between the concave hole into which the power transmission steel ball fits and the rolling trajectory surface of the steel ball a curved surface, and making the curved surface a groove with the same radius as the steel ball,
The steel ball enters the concave hole in line contact with the gently curved surface and rolls out from the concave hole, which prevents damage to the steel ball and the connection between the concave hole and the steel ball rolling surface. The torque value when activated when the releaser is overloaded remains stable even after repeated activation.
Its lifespan can be significantly extended.

<Function> With the above configuration, the connecting portion between the concave hole and the steel ball rolling surface becomes a gently curved surface, and the steel balls smoothly move into or out of the concave hole from the rolling surface in a line contact state.
In addition, even if the steel ball collides with the connecting part on the exit side of the recessed hole during transfer, the steel ball and its opposing surface will not be damaged by the impact.
Damage can be prevented.

<Embodiment> In the embodiment shown in FIGS. 1 and 2, 1 is an annular input member fixed to an input shaft (not shown);
Reference numeral 2 denotes a cylindrical output member fixed to an output shaft (not shown), and the output member 2 is fitted to the front outside of the input member 1 so as to be rotatable but not to move in the axial direction. ing.

Reference numeral 3 denotes a steel ball holding part integrally formed on a part of the outer periphery of the input member 1 over the entire circumference. A power transmission steel ball 5 whose diameter is larger than the wall thickness is loosely fitted.

Reference numeral 6 denotes a steel ball rolling surface of the output member 2, and a plurality of concave holes 7 for receiving the steel balls 5 are formed in this rolling surface 6.

Reference numeral 8 denotes a ring-shaped sliding plate fitted to the outside of the input member 1 on the rear side of the steel ball holder 3 so that it can move forward and backward; 9 denotes a plurality of disc springs provided on the rear side; A thrust bearing 10 is attached to the rear part, and a tightening nut 11 screwed onto a male thread on the outer periphery of the rear part of the input member 1 connects the sliding plate 8 to each steel ball 5 via the thrust bearing 10 and the disk spring 9.
It is crimped.

Further, in the embodiment, the recessed hole 7 has a concave spherical shape that fits a part of the steel ball 5 as shown in FIG.

Incidentally, the reference numeral 12 is a slotted hole.

In this invention, in order to prevent the steel ball 5 from passing through a sharp angular surface between the concave hole 7 and the steel ball rolling surface 6 due to overload, this portion has a gently curved surface and its cross section. A groove 13 is formed on a convex curved surface having the same radius as the steel ball 5. In addition, reference numeral 14 in the figure is a rotation prevention ring for the nut 11.

In the case of the above embodiment, when the input member rotates during normal operation, the steel ball 5 engages with the recessed hole 7 as shown in FIG. Rotation is transmitted to the output member 2 via 3.

If an excessive load is applied to the output side 2 for some reason and rotation is hindered, the sliding plate 8 compresses the spring 9 and retreats as the steel ball 5 escapes from the concave hole 7. However, the steel ball 5 is pushed out from the recessed hole 7 through the groove 13 on the convex curved surface and onto the steel ball rolling surface 6, so that an excessive load is not transmitted to the input member. Also steel ball 5
When it transfers from the rolling surface 6 into the recessed hole 7, it passes through the groove 13 on the convex curved surface, and the impact at the time of transfer is alleviated.

<Effects of the Invention> The present invention provides a structure in which the connecting portion between the concave hole provided in the rolling surface into which the power transmission steel ball is inserted and the steel ball rolling trajectory surface is a gently curved surface, and the cross section thereof has the same radius as the steel ball. Since we provided a groove on the convex curved surface, when the steel ball rolls out of the concave hole during overload, it passes through the groove on the convex curved surface, and the steel ball and its The opposing contact surfaces pass over a gently curved surface in a line contact state. A similar situation occurs when the steel ball moves into the recessed hole.

When the transfer speed is high, even if the steel ball transfers out side of the recessed hole collides with the conventional sharp angular surface, the effect of the impact is small and the durability is greatly extended, as well as its function is stabilized for a long time. It is possible to provide a torque reliever that is maintainable and highly reliable.

[Brief explanation of drawings]

Fig. 1 is a partially longitudinal side view showing an example of a torque reliever embodying the present invention, Fig. 2 is an enlarged longitudinal sectional view taken longitudinally in the radial direction of a steel ball engaging portion for power transmission, and Fig. Figure 2 is an enlarged vertical cross-sectional view taken along line A-A, Figure 4 is an enlarged vertical cross-sectional view taken along line B-B and CC in Figure 3, and Figure 5 has a recessed hole and a steel ball rolling surface. It is a partially cutaway enlarged perspective view of the part. DESCRIPTION OF SYMBOLS 1...Input member, 2...Output member, 3...Steel ball holding part, 4...Through hole, 5...Steel ball for power transmission, 6
... Steel ball rolling surface, 7 ... Recessed hole, 13 ... Arc-shaped groove.

Claims (1)

[Claims] 1 Multiple steel balls pressed by a spring material are fitted into a recessed hole to connect the input side member and the output side member, and when an excessive load is applied to the output side, the steel balls escape from the recessed hole. In the torque releaser, the torque releaser has a rolling surface that releases the connection between the input side member and the output side member and connects the steel ball escaped from the recessed hole to the next recessed hole, a recessed hole into which the steel ball is fitted; The connection part with the rolling surface of the steel ball that escaped from the concave hole is made into a curved surface,
A torque releaser characterized in that the cross section of the curved part is a gentle groove with the same radius as the steel ball.