JP2604078Y2 - Planetary roller type power transmission - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary roller type power transmission suitable for a high-precision speed reducer.

[0002]

2. Description of the Related Art In a precision feed mechanism, a planetary roller type power transmission device is used as a high-precision speed reducer. As shown in FIGS. 3 and 4, this type of planetary roller type power transmission device includes an outer ring 22 fixed to a housing 21, a sun shaft 23 concentrically arranged inside the outer ring 22, and a sun shaft 23. A plurality of planetary rollers 24,... Are interposed in a press-contact manner between 23 and the outer ring 22, and a carrier 25 that rotates in conjunction with the revolution of each planetary roller 24.

[0003] The carrier 25 comprises a rotating shaft 26 and a rotating shaft 2.
6 comprises a circular plate 27 fixed to one end and a plurality of planetary shafts 28 cantilevered at several locations on the outer circumference of the circular plate 27. Each planetary shaft 28 is provided with a respective planetary roller 24. It is rotatably fitted to the outside via a rolling bearing 29. In a single-stage device, the sun shaft 23 is a high-speed input / output shaft, and the carrier 25 is directly connected to a low-speed input / output shaft.

[0004] In such a planetary roller type power transmission device, it is required that there be no backlash in order to improve the accuracy as a speed reducer.

[0005]

Generally, in a planetary roller type power transmission device, a planetary roller 24 and an outer ring 2 are provided.
By setting the interference between them as negative, a rotational driving force is applied to the planetary rollers 24. Because of this relationship, the planetary roller 24 is slightly deformed inside the outer ring 22. To allow such deformation of the planetary roller 24, the inner diameter of the planetary roller 24 and the rolling bearing 2 are adjusted.
A gap of, for example, about 5 to 10 μm is provided between the outer diameter 9 and the outer diameter 9.

However, since such a gap is provided, when the planetary roller 24 is deformed, the gap is distributed before and after the revolving direction of the planetary roller 24, and the gap increases by that amount. The presence of such a gap causes the carrier 25 to rattle with respect to the planetary rollers 24 when the rotation speed fluctuates suddenly or when the rotation direction is reversed, so that backlash occurs.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to eliminate backlash due to backlash of a carrier and to enable high-accuracy deceleration.

[0008]

SUMMARY OF THE INVENTION The present invention provides a stationary outer ring, a sun shaft concentrically disposed inside the outer ring, and a plurality of planets interposed between the sun shaft and the outer ring in a press-contact manner. Roller and each planetary roller are rotatably supported and
For example Bei and a carrier which rotates in conjunction with the revolution of the star roller,
Before the planetary rollers revolving direction relative to the front Ki遊 Star roller
A configuration is provided in which a pressing roller is pressed so as to be pressed to either one of the rear .

[0009]

The planetary roller is biased in one of the revolving directions by pressing the pressing roller against the planetary roller in one of the revolving directions of the planetary roller. The gap existing between them is filled in the revolving direction of the planetary roller, so that there is no backlash in the revolving direction of the planetary roller, that is, backlash. Therefore, when the carrier is the output shaft,
The output carrier does not rattle in the revolving direction.

[0010]

1 and 2 show an embodiment of the present invention. FIG. 1 is a cross-sectional view (longitudinal front view) of the planetary roller type power transmission device along a direction orthogonal to the axis, and FIG. 2 is a cross-sectional view (longitudinal side view) along the axial direction.

The illustrated planetary roller type power transmission device has an outer ring 2 fixed to a housing 1, a sun shaft 3 concentrically disposed inside the outer ring 2, and a sun shaft 3 and the outer ring 2 between the sun shaft 3 and the outer ring 2. And a carrier 5 that rotates in conjunction with the revolution of the planetary roller 4. The basic configuration is almost the same as that of the conventional device. . The carrier 5 includes a rotating shaft 6, a circular plate 7 fixed to one end of the rotating shaft 6, and a plurality of planetary shafts 8 cantilevered at several locations on the outer circumference of the circular plate 7.
The same applies to the configuration in which each planetary roller 4 is rotatably fitted to each of the planetary shafts 8 via rolling bearings 9.

The apparatus of this embodiment differs from the conventional apparatus in that a pressing roller 10 is disposed between adjacent planetary rollers 4 and 4, and the pressing roller 10 is rotatably pressed against the outer peripheral surface of the planetary roller 4. That is.

More specifically, in this embodiment, two pressing rollers 10, 10 are provided with respect to four planetary rollers 4,.
And each pressing roller 10 is located between two adjacent planetary rollers 4, 4, and the two planetary rollers 4, 4 are widened so as to widen the space between the two planetary rollers 4, 4. 4 is pressed. Also, in this embodiment,
An auxiliary carrier plate 11 is provided at a position facing the circular plate 7 of the carrier 5 with the planetary roller 4 interposed therebetween.
A roller shaft 12 is mounted between the auxiliary carrier plate 11 and the circular plate 7 of the carrier 5 in a bridging manner, and the pressing roller 10 is rotatably supported on the roller shaft 12 via a needle roller (not shown). Have been.

In the above configuration, a slight gap is provided between the planetary roller 4 and the rolling bearing 9, but each of the planetary rollers 4 is always pressed toward the planetary shaft 8 by a pressing roller 10 from a fixed direction. Because the above gap is a planet
Roller 4 is packed in the revolving direction,
There is no play in the revolution direction . Therefore, no backlash occurs.

In the illustrated embodiment, one pressing roller 9 is pressed against two planetary rollers 4, 4, but one pressing roller 9 is provided for each of the planetary rollers 4,. The pressing rollers may be configured to be brought into pressure contact with each other, or may be configured to be combined with each other.

[0016]

As described above, according to the present invention, even if a gap is provided between the planetary roller and the carrier, the gap can be eliminated by filling in the revolving direction of the planetary roller. The rattling of the carrier with respect to the planetary rollers can be eliminated. Therefore, it is possible to prevent the occurrence of backlash due to the gap in the revolving direction of the planetary rollers, and it is possible to control even minute deceleration output with high accuracy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view of an embodiment of a planetary roller type power transmission device of the present invention.

FIG. 2 is a longitudinal side view of the device.

FIG. 3 is a longitudinal sectional front view of a conventional planetary roller type power transmission device.

FIG. 4 is a longitudinal sectional side view of the device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Outer ring 3 Sun axis 4 Planetary roller 5 Carrier 10 Pressing roller

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-49-135074 (JP, A) JP-A-53-9966 (JP, A) JP-A-57-171156 (JP, A) JP-A-59-171 80557 (JP, A) US Pat. No. 3,673,214 (US, A) US Pat. No. 3,392,604 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 13/08

Claims (3)

(57) [Scope of request for utility model registration] And 1. A fixed outer ring, a sun shaft arranged concentrically inside the outer ring, a plurality of planetary rollers interposed pressed manner between the sun shaft and the outer ring, the respective planetary rollers respectively
E Bei a carrier that rotates in conjunction with the revolution of the rotatably support and the planetary rollers are in contact so as to press the planetary rollers to either before or after the revolving direction relative to the front Ki遊 Star roller A planetary roller type power transmission device comprising a pressing roller. 2. The number of said planetary rollers is even and
It number of serial pressing roller to half of the planetary rollers
Is being set, one pressing rollers the two planetary row La for two planetary rollers adjacent to each other in the circumferential direction
It is in contact so as to press the opposite directions to each other with the revolution direction
That the planetary roller type power transmission device according to claim 1, characterized in that. 3. The planetary roller type power transmission device according to claim 1 , wherein the number of the pressing rollers is set to be equal to the number of the planetary rollers.