JPH0617894A - Epicyclic friction type speed change gear - Google Patents

Abstract

PURPOSE:To position a retainer and steel balls smoothly by forming a tapered face at the tip part of the retainer. CONSTITUTION:In the case of assembling an epicyclic friction type speed change gear, an elastic member 8a and an outer ring 7b are disposed coaxially with a motor shaft 4, and plural steel balls 6 are disposed at almost equal spaces apart. The elastic member 8a and the outer ring 7a are disposed in such a way as to cover plural steel balls 6. An upper casing 3 with a pinion 11 and a retainer 9 previously fitted thereto is thrust into a lower casing 2 for fixing. At this time, even if plural steel balls 6 are slightly out of the normal positions, these steel balls 6 are moved into the normal positions being guided by a tapered part 9b formed at the tip part of the retainer 9 at the time of inserting the retainer 9, so that the retainer 9 can be inserted smoothly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary friction transmission.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show an example of a conventional planetary friction transmission. FIG. 4 is a longitudinal sectional view showing the structure of a conventional planetary friction transmission, and FIG. 3 is a transverse sectional view thereof. 4 and 5, 1 is a motor, 2 is a lower casing, 3
Is an upper casing, 4 is a motor shaft, 5 is a sun roller fixed to the motor shaft 4, 6 is a steel ball which is a planetary rolling element, and ring-shaped 7a and 7b are outer rings. Reference numerals 8a and 8b are elastic members for applying a preload for pressing the sun roller 5, the steel ball 6, and the outer rings 7a and 7b with a predetermined pressure. Reference numeral 9'is a retainer for holding the plurality of steel balls 6 at predetermined intervals, and 10 is an output shaft, which is fixed to the retainer 9 '.

Outer rings 7a and 7b are sun rollers 5.
It is arranged coaxially with. A plurality of steel balls 6 are sandwiched between the outer peripheral surface of the sun roller 5 and the inner peripheral surfaces of the outer rings 7a and 7b.
Are held by the retainer 9 ′ at substantially equal intervals. An output shaft 10 is connected (fixed) to the retainer 9'and is rotatably fitted to the output shaft bearing portion 3a. Outer ring 7a by elastic members 8a and 8b
7b and the plurality of steel balls 6 and the sun roller 5 are pressed against each other with a predetermined pressing force.

In the above structure, when the sun roller 5 rotates, the outer rings 7a and 7b, the plurality of steel balls 6 and the sun roller 5 are brought into contact with each other with a predetermined pressing force by the elastic members 8a and 8b. The steel ball 6 revolves along with the retainer 9 ′ while rotating, and the output shaft 10 is decelerated at the revolution speed of the plurality of steel balls 6.

[0005]

Generally, when assembling such a planetary friction type transmission, first, a plurality of steel balls are arranged at approximately equal intervals between the outer rings 7a and 7b and the sun roller 5, and then, Insert the retainer from above so as to sandwich the steel ball with.

In the conventional transmission shown in FIG. 4, the retainer has a shape with a constant width in the axial direction, and the steel ball must be precisely positioned at a predetermined position when the retainer is inserted. The steel ball did not enter the recess of the retainer, so the retainer could not be incorporated, and the assembly was difficult.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, according to the present invention, a tapered surface is formed at a tip of a retainer so that a steel ball is positioned to a certain extent, so that a steel is incorporated when the retainer is assembled. The ball is guided by its tapered surface so that it can be easily set in the steel ball storage position of the retainer, and a planetary friction transmission with good assembly is realized.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a drawing showing the structure of the apparatus of the first embodiment of the present invention, and is a vertical sectional view showing the configuration of the present embodiment. Figure 1
In the above, 1 is a motor, 2 is a lower casing, 3 is an upper casing, and the bearing portion 3a is integrally formed. 4 is a motor shaft, 5 is a sun roller connected to the motor shaft 4, and 6 is a steel ball as a planetary rolling element (3 in the embodiment).
), 7a and 7b are outer rings. 8a and 8
b is an elastic member such as silicon rubber. Reference numeral 9 is a retainer for holding the steel ball 6, and a tapered portion 9b is provided on the inner peripheral surface of the tip portion. An output shaft 10 is integrally formed with the retainer 9. Reference numeral 11 is a pinion gear fixed to the output shaft 10, and the rotation of the motor shaft 4 is decelerated and output. The pair of outer rings 7a and 7b are arranged substantially coaxially with the sun roller 5. In the outer rings 7a and 7b, the rolling surfaces 7a-1 and 7b-1 of the steel ball 6 are tapered and the elastic members 8a and 8b are held on the entire circumference of the surfaces facing the upper and lower casings 2 and 3. Notches 7a-2 and 7b-2 for making the cut are provided. The outer rings 7a, 7b are arranged so that the respective tapered surfaces 7a-1, 7b-1 face each other, and the outer peripheral cylindrical surface of the sun roller 5 and the inner peripheral tapered surfaces 7a-1,
The three steel balls 6 sandwiched by 7b-1 are held by a retainer 9 at substantially equal intervals. Retainer 9 is steel ball 6
A plurality of legs 9a are formed so as to hold the steel balls with an appropriate gap, and the steel balls 6 can freely roll between the legs 9a. The retainer 9 and the output shaft 10 are integrally formed of plastic, for example, and are rotatably supported by the output shaft bearing portion 3a. A pinion gear 11 is fixed to the tip of the output shaft 10, and the play of the output shaft 10 in the thrust direction is restricted by the pinion gear 11 contacting the bearing portion 3a. The outer rings 7a and 7b are supported by elastic members 8a and 8b so as not to come into direct contact with the upper and lower casings 2 and 3, and the outer rings 7a and 7b are supported by the elastic members 8a and 8b.
a, 7b and the plurality of steel balls 6 and the sun roller 5 are pressed against each other with a predetermined pressing force. Outer rings 7a, 7
The outer rings 7a and 7b are prevented from rotating when the steel balls 6 roll due to the frictional force between b and the elastic members 8a and 8b and between the elastic members 8a and 8b and the upper and lower casings 2 and 3. The lower casing 2 is fixed to the motor 1 with mounting screws 12. The outer peripheral portion of the lower casing 2 and the inner peripheral portion of the upper casing 3 are cut with a male screw and a female screw that engage with each other, and the upper casing 3 is screwed and fixed to the lower casing 2. The outer rings 7a, 7b
The outer diameters of the outer peripheral surfaces 7a-3 and 7b-3 are designed to be considerably smaller than the inner diameter of the inner peripheral surface 2a of the lower casing 2, and the outer diameters of the elastic members 8a and 8b are also lower. Since it is designed to be considerably smaller than the inner diameter of the inner peripheral surface 2a, the outer rings 7a and 7b can be slightly moved in the radial direction.

Next, the operation of the planetary friction type transmission configured as described above will be described.

When the motor shaft 4 rotates, the outer rings 7a, 7b are in contact with the plurality of steel balls 6 and the sun roller 5 by the elastic members 8a, 8b with a predetermined pressing force. While rotating on its axis, it revolves on the tapered surfaces of the outer rings 7a, 7b together with the retainer 9, and the output shaft 10 is decelerated at the revolution speed of the plurality of steel balls 6.

The outer rings 7a, 7b are made of elastic bodies 8a, 8
Since it is held only by b and is not constrained in the radial direction, the planetary friction transmission is operated to repeatedly receive a force, and the outer rings 7a, 7b move to a position coaxial with the sun roller 5. Automatically adjusted.

Further, the elastic members 8a and 8b can absorb the vibrations of the outer rings 7a and 7b generated by the rolling of the steel balls 6 without transmitting them to the outside, resulting in low vibration, low noise and highly efficient gear shifting. The device can be realized.

When assembling this apparatus, first, the elastic member 8a and the outer ring 7b are arranged substantially coaxially with the motor shaft 4, and then the plurality of steel balls 6 are arranged at substantially equal intervals.
The elastic member 8a and the outer ring 7a are connected to the plurality of steel balls 6
Place it so that it covers it. Then, the upper casing 3 to which the pinion 11 and the retainer 9 are attached in advance is screwed and fixed to the lower casing 2.

At this time, even if the plurality of steel balls 6 are slightly displaced from their proper positions, the retainer 9 is inserted when the retainer 9 is inserted.
The retainer 9 can be inserted smoothly because it moves to the proper position by being guided by the taper portion 9b at the tip portion.

[0015]

Other Embodiments FIGS. 2 and 3 show a second embodiment of the present invention. 2 is a longitudinal sectional view of this embodiment, and FIG. 3 is a lateral sectional view thereof. In this embodiment, a roller 13 is provided on the retainer 9A, and the tip portion 13a of the roller 13 is formed in a conical shape in which the tip direction becomes narrower, and the same effect as that of the first embodiment is obtained. By providing the retainer with the rollers as described above, friction loss between the planetary rolling elements and the retainer portion can be reduced, and thus a more efficient planetary friction transmission can be realized.

[0016]

As described above, according to the present invention,
Even if the steel ball is slightly displaced from the normal position when assembling the planetary friction transmission, the steel ball moves to the normal position while being guided by the tapered surface of the retainer tip when the retainer is inserted. Since the retainer and the steel ball can be positioned at the position, the device can be easily assembled, and the planetary friction transmission having good assemblability can be realized.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of a planetary friction transmission according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing the structure of a planetary friction transmission according to a second embodiment of the present invention.

3 is a cross-sectional view of FIG.

FIG. 4 is a vertical cross-sectional view showing the configuration of a conventional planetary friction transmission.

5 is a cross-sectional view of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Motor 2 ... Lower casing 3 ... Upper casing 3a ... Output shaft bearing 4 ... Motor shaft 5 ... Sun roller 6 ... Steel ball 7a ... Outer ring 7b ... Outer ring 8a ... Elastic member 8b ... Elastic member 9 ', 9, 9A ... Retainer 9b ... Taper 10 ... Output shaft 13 ... Roller

Claims (1)

[Claims] 1. A plurality of spherical planetary rolling elements held by a retainer so as to come into contact with the outer circumferential surface of the sun roller and the inner circumferential surface of the outer ring, respectively, and the planetary rolling element is rotated by the rotation of the sun roller. Revolve around the outer ring,
In the planetary friction transmission which obtains the output rotation decelerated by the revolution, the retainer is provided with a tapered surface at a tip end portion thereof.