Reduction gear

Patent metadata

Field	Value
Publication number	US-9869383-B2
Application number	US-201615241266-A
Country	US
Kind code	B2
Filing date	Aug 19, 2016
Priority date	Sep 2, 2015
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

A reduction gear of the present invention is compact and light and can be used for tire portions of an apparatus for travelling, etc. Each of outer and inner pins is formed by a rolling bearing. The reduction gear includes block-shaped lubricating members which supply a lubricant to the outer rings of the outer pins to thereby lubricate them, and a ring-shaped lubricating member which supplies the lubricant to the outer rings of the inner pins to thereby lubricate them. The lubricant can be supplied to a pair of cycloid gears through the outer pins and the inner pins for lubrication. Since the cycloid gears, the outer pins, and the inner pins are lubricated by the lubricating members, the reduction gear can enhance its durability, reduce the friction between components to thereby lower the frictional resistance, and realize a light and compact structure.

First claim

What is claimed is:

1. A reduction gear comprising:
an input shaft having a pair of eccentric portions which are located adjacent each other in an axial direction of the input shaft and which have a phase difference of 180° therebetween in a circumferential direction of the input shaft;
a pair of cycloid gears which rotate in contact with outer circumferences of the corresponding eccentric portions;
a hub which is located adjacent to the cycloid gears, rotatably supports the input shaft, and serves as an output shaft;
an output shaft pin holder which is fixed to the hub, with the cycloid gears intervening between the output shaft pin holder and the hub, and which rotatably supports the input shaft;
a plurality of outer pins which roll on peripheral tooth surfaces of tooth portions of the cycloid gears;
an outer pin holder which holds the outer pins such that the outer pins are spaced from one another in the circumferential direction and which rotatably supports the hub and the output shaft pin holder;
a plurality of inner pins which roll on wall surfaces of a plurality of insertion holes formed in the cycloid gears and which are supported by the hub; and
a plurality of lubricating members which are in contact with the outer pins and the inner pins and lubricate the outer pins and the inner pins.

2. The reduction gear according to claim 1 , wherein the hub is rotatably supported by the outer pin holder through a cross roller bearing.

3. The reduction gear according to claim 1 , wherein a gear separator ring is disposed between the cycloid gears, and thrust washers are built in to be located on opposite sides of the cycloid gears where the cycloid gears are in sliding contact with other members.

4. The reduction gear according to claim 1 , wherein each of the outer pins and the inner pins is a rolling bearing which is composed of a shaft, a pair of outer rings rotatably disposed on the shaft, and a plurality of rollers rolling between the outer rings and the shaft; and
side plates are disposed at axially opposite ends of the outer pins and the inner pins.

5. The reduction gear according to claim 4 , wherein the shafts of the outer pins are attached between the outer pin holder and an outer pin holder plate which is disposed around the output shaft pin holder and faces the outer pin holder, with the cycloid gears intervening between the outer pin holder plate and the outer pin holder.

6. The reduction gear according to claim 4 , wherein the shafts of the input pins are attached between the hub and the output shaft pin holder which is disposed to face the hub with the cycloid gears intervening between the output shaft pin holder and the hub.

7. The reduction gear according to claim 1 , wherein the lubricating members include a block-shaped lubricating member which is elastically deformably fitted into and supported by a recess formed in the outer pin holder supporting the outer pins and which is in contact with the outer rings of the outer pins and lubricates the outer rings of the outer pins.

8. The reduction gear according to claim 7 , wherein the block-shaped lubricating member includes a lubricant supply portion composed of an inner circumferential surface of the lubricating member and opposite end surfaces of the lubricating member which are formed at opposite ends of the inner circumferential surface in the circumferential direction, the inner circumferential surface being in contact with the peripheral tooth surfaces of the tooth portions of the cycloid gears so as to lubricate the peripheral tooth surfaces, and the opposite end surfaces being in contact with the outer rings of the outer pins located adjacent to the block-shaped lubricating member so as to lubricate the outer rings of the outer pins.

9. The reduction gear according to claim 1 , wherein the lubricating members include a ring-shaped lubricating member which is fitted to and supported by an inner circumferential surface of a gear separator ring disposed between the cycloid gears and which lubricates the inner pins.

10. The reduction gear according to claim 9 , wherein the ring-shaped lubricating member has a lubricant supply portion which is formed over the entirety of an inner circumferential surface of the ring-shaped lubricating member and is in contact with the outer rings of the inner pins so as to lubricate the outer rings of the inner pins.

11. The reduction gear according to claim 1 , wherein each of the lubricating members is a porous molded member impregnated with a lubricant.

12. The reduction gear according to claim 1 , wherein the outer pin holder has a plurality of T-slot-shaped cutouts spaced from one another in the circumferential direction, and head portions of bolts for fixing a motor attached to the reduction gear are disposed in the cutouts.

13. The reduction gear according to claim 1 , wherein an output shaft of a motor driving the input shaft is connected to the input shaft, and a wheel including a tire is attached to the hub.

Assignees

• Nippon Thompson Co Ltd

Inventors

• Sasaki Satoshi

Classifications

• B60Y2306/03

  Lubrication · CPC title

• F16H57/0406 Primary

  Absorption elements for lubricants, e.g. oil felts · CPC title

• F16H57/0486

  with fixed gear ratio  (axle or inter-axle differentials F16H57/0483) · CPC title

• F16H2001/325

  comprising a carrier with pins guiding at least one orbital gear with circular holes · CPC title

• B60K7/0007

  the motor being electric · CPC title