JPH0612859U - Planetary roller type power transmission device - Google Patents

Abstract

(57) [Summary] [Purpose] In a planetary roller power transmission system, eliminate backlash due to rattling of the carrier. [Structure] A fixed outer ring 2, a sun shaft 3 arranged concentrically inside the outer ring 2, a plurality of planet rollers 4 interposed in a pressure-contact manner between the sun shaft 3 and the outer ring 2, and a planet. In a planetary roller type power transmission device including a carrier 5 that rotates in association with the revolution of the roller 4, a pressing roller 10 that is rotatably pressed only to the planetary roller 4 between adjacent planetary rollers 4 and 4 includes a carrier 5 and a carrier 5. Is supported by. The planetary roller 4 is pressed in the revolving direction by the pressure contact force of the pressing roller 10, so that the gap existing between the planetary roller 4 and the carrier 5 disappears in the revolving direction of the planetary roller 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a planetary roller type power transmission device suitable for a high precision speed reducer.

[0002]

[Prior art]

 The precision feed mechanism uses a planetary roller power transmission device as a high-accuracy 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 arranged concentrically inside the outer ring 22, and a sun shaft. A plurality of planet rollers 24, which are interposed between the outer ring 22 and the outer ring 22 in a pressure contact manner, and a carrier 25 which rotates in association with the revolution of each planet roller 24 are provided.

The carrier 25 includes a rotary shaft 26, a circular plate 27 fixed to one end of the rotary shaft 26, and a plurality of planetary shafts 28 supported in a cantilever manner at several circumferential positions on the outer peripheral side of the circular plate 27. Each planetary roller 24 is rotatably fitted on each planetary shaft 28 via a rolling bearing 29. In a device having a single stage of acceleration / deceleration, the sun shaft 23 serves as a high speed input / output shaft, and the low speed input / output shaft is directly connected to the carrier 25.

Such a planetary roller power transmission device is required to have no backlash in order to improve accuracy as a speed reducer.

[0005]

[Problems to be solved by the device]

 By the way, generally, in the planetary roller type power transmission device, a rotational driving force is applied to the planetary roller 24 by making the interference between the planetary roller 24 and the outer ring 22 negative. From this relationship, the planetary roller 24 is slightly deformed inside the outer ring 22, and therefore, in order to allow such deformation of the planetary roller 24, between the inner diameter of the planetary roller 24 and the outer diameter of the rolling bearing 29. For example, a gap of about 5 to 10 μm is provided.

However, since such a gap is provided, when the planetary roller 24 is deformed, the gap is distributed before and after the orbital direction of the planetary roller 24, and the gap increases by that amount. Due to the existence of such a gap, the carrier 25 rattles against the planetary rollers 24 when the rotational speed fluctuates rapidly or when the rotational direction is reversed, which causes backlash. .

In view of the above conventional problems, it is an object of the present invention to eliminate backlash due to rattling of a carrier and enable deceleration with high accuracy.

[0008]

[Means for Solving the Problems]

 The present invention has a fixed outer ring, a sun shaft concentrically arranged inside the outer ring, a plurality of planet rollers interposed in a pressure contact state between the sun shaft and the outer ring, and a revolution of each planet roller. A planetary roller power transmission device including a carrier that rotates in conjunction with the planetary roller power transmission device is configured to include a pressing roller that is pressed against the planetary roller while being rotatably supported by the carrier.

[0009]

[Action]

 For example, when the planetary roller is pressed in the revolving direction by the pressing roller, the gap existing between the planetary roller and the carrier disappears in the revolving direction of the planetary roller. Therefore, when the carrier serves as the output shaft, the output carrier does not rattle in the direction of revolution.

[0010]

【Example】

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

The planetary roller type power transmission device of the illustrated example has an outer ring 2 fixed to a housing 1, a sun shaft 3 concentrically arranged inside the outer ring 2, and a space between the sun shaft 3 and the outer ring 2. The structure is provided with a plurality of planet rollers 4, which are interposed in pressure contact with each other, and a carrier 5 that rotates in conjunction with the revolution of the planet roller 4. The basic structure is almost the same as that of the conventional device. is there. Further, 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 supported in a cantilever manner at several circumferential positions on the outer peripheral side of the circular plate 7. The planetary rollers 4 are rotatably fitted to the respective planetary shafts 8 via rolling bearings 9 in the same manner.

The difference between the apparatus of this embodiment and the conventional apparatus is that a pressing roller 10 is arranged between adjacent planet rollers 4 and 4, and the pressing roller 10 is rotatably pressed against the outer peripheral surface of the planet roller 4. It is that.

Specifically, in this embodiment, two pressing rollers 10, 10 are used for the four planet rollers 4, ... It is located between the planetary rollers 4 and 4 and is pressed against both planetary rollers 4 and 4 so as to widen the space between the two planetary rollers 4 and 4. Further, 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, and between the auxiliary carrier plate 11 and the circular plate 7 of the carrier 5, A roller shaft 12 is attached in a bridge shape, and the pressing roller 10 is rotatably supported on the roller shaft 12 via a needle roller or the like (not shown).

In the above configuration, a slight gap is provided between the planetary roller 4 and the rolling bearing 9, but each planetary roller 4 is always pushed from the fixed direction to the planetary shaft 8 side by the pressing roller 10. Since it is pressed, the above-mentioned gap is eliminated, and therefore backlash does not occur.

In the illustrated embodiment, one pressing roller 9 is brought into pressure contact with the two planet rollers 4, 4, but each planet roller 4 ,. One pressing roller may be configured to be in pressure contact with each other, or they may be combined.

[0016]

[Effect of device]

 As described above, according to the present invention, even if there is a gap between the planet roller and the carrier, the gap can be eliminated in the revolution direction of the planet roller. Rattling can be eliminated. Therefore, it is possible to prevent the occurrence of backlash due to the clearance in the direction of revolution of the planetary rollers, and it becomes possible to control with high precision even with a minute deceleration output.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional side view of the device.

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

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

[Explanation of symbols]

 1 Housing 2 Outer Ring 3 Sun Axis 4 Planetary Roller 5 Carrier 10 Pressing Roller

Claims (3)

[Scope of utility model registration request] 1. A fixed outer ring, a sun shaft concentrically arranged inside the outer ring, a plurality of planet rollers interposed in pressure contact between the sun shaft and the outer ring, and revolutions of each planet roller. A planetary roller type power transmission device including a carrier that rotates in conjunction with, comprising a pressing roller that is pressed against the planetary roller while being rotatably supported by the carrier,
A planetary roller type power transmission device characterized in that 2. The planetary roller type power transmission device according to claim 1, wherein the pressing roller is pressed against the planet rollers adjacent to each other in the circumferential direction at the same time. 3. The planetary roller type power transmission device according to claim 1, wherein the pressing roller is pressed against a single planetary roller.