JPS6237560A - Differential planetary roller reduction gear - Google Patents

Abstract

PURPOSE:To make backlash reduced to the smallest possible extent by coupling an outer ring, a casing and an output shaft together so as to take no clearance among them. CONSTITUTION:A planetary roller 2 is supported by a retainer 3 so as to do rolling contact on an outer circumferential surface of a sun shaft 1 serving as an input shaft later, and then two outer rings 5 and 4 are subjected to shrinkage fit in both large and small diametral parts 2a and 2b of this planetary roller 2. A coupling convex part 4a of the first outer ring 4 and a coupling concave part 8a of a case at the input side as well as a coupling convex part 5a of the second outer ring 5 and a coupling concave part 6a of an output shaft 6 are all pressed in and locked to each in a state of no clearance, and opening part themselves of the input shaft side case 8 and an output side case 9 are joined together by welding. When the sun shaft 1 rotates in this way, it rotates as far as for a difference between rotation and revolution of the planetary roller 2, and decelerating rotational output is taken out by the output shaft 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a differential planetary roller speed reducer using a rolling planetary mechanism.

[Background Art] The most common type of reducer is a gear type, but this does not have a large reduction ratio and also causes backlash between meshing gears. Therefore, when a high speed reduction ratio and low backlash are required, a differential planetary roller speed reducer using a rolling planetary mechanism is used.

As shown in Figure 4, this type of device obtains deceleration output from a retainer B that supports planetary roller A, and as shown in Figure 5, it is connected to outer ring C that circumscribes the planetary roller with a small clearance. There are some that obtain deceleration output from the output shaft. The former is due to the clearance of the support part of roller A, and the latter is due to the clearance between the outer ring C and the output shaft.
Although it is not as severe as the gear type, batho crush occurs.

[Object of the Invention] The present invention has been made in view of the above reasons, and its object is to provide a differential planetary roller speed reducer with extremely low backlash.

[Disclosure of the Invention] The differential planetary roller speed reducer of the present invention includes a sun shaft, a plurality of planetary rollers having a large diameter portion and a small diameter portion, supported by a retainer, and rolling in contact with the outer peripheral surface of the sun shaft; A first outer ring in which the small diameter portion of the planetary roller is inscribed, a second outer ring in which the large diameter portion of the planetary roller is inscribed, an output shaft coupled to the second outer ring, and a sun shaft and the output shaft are rotatable. In a differential planetary roller reducer consisting of a casing that supports and is connected to a first outer ring, the connection between the first outer ring and the casing and the connection between the second outer ring and the output shaft are fixed connections without clearance. It is characterized by

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

1 is a sun shaft which becomes the input shaft of the speed reducer.

2 is a planetary roller having a large diameter part 2a and a small diameter part 2b, a plurality of which are rotatably supported by a retainer 3. Specifically, a shaft portion 2C continuous to the center axis of the planetary roller 2
is supported by being inserted into the shaft hole 3a of the retainer 3,
As a result, the plurality of planetary rollers 2 are arranged at equal intervals around the sun shaft 1, and each large diameter portion 2a rolls into contact with the outer peripheral surface of the sun shaft 1.

Reference numeral 4 denotes a first outer ring in which the small diameter portion 2b of the planetary roller 2 is inscribed, and is connected to a casing to be described later. For this purpose, a plurality of coupling protrusions 4a for press-fit coupling are provided on the outer peripheral surface (for example, 3 (hard)) at approximately equal intervals.Furthermore, the coupling protrusions 4a have an axially tapered shape as shown in the second figure. The width is narrower at the tip end during the joining process.

Reference numeral 5 denotes a second outer ring in which the large diameter portion 2a of the planetary roller 2 is inscribed (therefore, the inner diameter is larger than the first outer ring 4), and is coupled to an output shaft to be described later.

The coupling protrusion 5a for press-fit coupling for this purpose is connected to the first outer ring 4.
Similar to the coupling protrusion 4a, it is provided as shown in the third figure.

These outer rings 4.5 are connected to the small and large diameter portions 2 of the planetary roller 2.
b and 2a are shrink-fitted to obtain the required pressure contact force.

Reference numeral 6 denotes an output shaft from which the deceleration output is taken out, one end of which is connected to the second outer ring 5, and the inner periphery of the intermediate portion rotatably supports the other end of the sun shaft 1. As shown in the third figure, one end side that is coupled to the second outer ring 5 has a cylindrical shape with an outer diameter approximately equal to the outer diameter of the coupling protrusion 5a of the second outer ring 5, and furthermore, the end side is coupled to the second outer ring 5. A tapered coupling recess 6a into which the protrusion 5a can be press-fitted is provided at a position corresponding to the protrusion 5a.

Reference numeral 7 denotes a casing that houses the above-mentioned members, rotatably supports the outer circumferential surfaces of the sun shaft 1 and the output shaft 6, and is coupled to the first outer ring 4. Specifically, this casing 7 is constructed by separately manufacturing an input side case 8 and an output side case 9, both of which are cup-shaped, and then joining and fixing the openings together. At the open end of the input side case 8 that connects with the first outer ring 4, there is a connecting protrusion 4 of the first outer ring 4, as shown in the second figure.
A tapered coupling recess 8a that has an inner diameter slightly larger than the outer diameter of a and can be press-fitted into a position corresponding to the coupling protrusion 4a.
is provided.

Thus, the planetary roller 2 is supported by the retainer 3 so as to be in rolling contact with the outer peripheral surface of the sun shaft 1, and then both outer rings 5.4 are shrink-fitted to the large and small diameter portions 2a and 2b of the planetary roller 2. Then, the coupling protrusion 4a of the first outer ring 4 and the coupling recess 8a of the input case 8, and the coupling protrusion 5a of the second outer ring 5 and the coupling recess 6a of the output shaft 6 are press-fitted and fixed with no clearance, respectively. , the openings of the input side case 8 and the output side case 9 are joined and fixed together.

In such a speed reducer, when the sun shaft 1 rotates, the planetary rollers 2 revolve around the sun shaft 1 while rotating. In this case, since the side outer rings 4 and 5 have different inner diameters, the second outer ring 5 rotates by the difference between the rotation and revolution of the planetary roller 2, and its deceleration rotation output is taken out from the output shaft 6.

In the embodiment, the connecting portions between the first outer ring 4 and the casing 7 and the second outer ring 5 and the output shaft 6 are press-fitted with connecting protrusions and connecting recesses provided at approximately equal intervals (so-called spline shape). Although fixed means have been described, the present invention is not limited to this, and other fixing means may be used.

[Effects of the Invention] Since the differential planetary roller speed reducer of the present invention is constructed as described above, there is no clearance between the first outer ring and the casing and between the joint parts between the second outer ring and the output shaft. , the bathocrush becomes extremely small.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing an embodiment of the present invention.
FIG. 3 is a perspective view of a main part showing a joint between the first outer ring and the casing; FIG. 3 is a perspective view of a main part showing a joint between the second outer ring and the output shaft; FIG. 4 is a conventional example; (a) is a sectional view, (b) is a plan view, and FIG. 5 is a perspective view showing another conventional example. 1-sun axis, 2-planetary roller, 3--retainer, 4-
1st outer ring, 5 - second outer ring, 6 - output shaft, 7 - casing. Patent Applicant Matsushita Electric Works Co., Ltd. Patent Attorney Toshimaru Takemoto (and 2 others) 2 Stroller Roller Diagram 2

Claims (1)

[Claims] (1) A sun shaft, a plurality of planetary rollers having a large diameter part and a small diameter part, supported by a retainer and rolling into contact with the outer peripheral surface of the sun shaft, and a first planetary roller in which the small diameter part of the planetary roller is inscribed.
a second outer ring in which the large diameter portion of the planetary roller is inscribed; an output shaft coupled to the second outer ring; A differential planetary roller reducer comprising a casing coupled to an outer ring, characterized in that the coupling between the first outer ring and the casing and the coupling between the second outer ring and the output shaft are fixed couplings without clearance. differential planetary roller reducer.