Transmission

Patent metadata

Field	Value
Publication number	US-12546362-B2
Application number	US-202218292933-A
Country	US
Kind code	B2
Filing date	Jul 26, 2022
Priority date	Jul 30, 2021
Publication date	Feb 10, 2026
Grant date	Feb 10, 2026

Abstract

A transmission includes a first shaft unit connected to a drive shaft of a drive unit. The first shaft unit includes a first shaft having a first shaft raceway surface on an outer peripheral surface thereof, a first output gear provided on the first shaft, a first outer ring attached to a first support part, the first outer ring having a first outer ring raceway surface on an inner peripheral surface thereof, and a plurality of first rolling elements disposed between the first shaft raceway surface and the first outer ring raceway surface.

First claim

The invention claimed is:

1 . A transmission comprising a first shaft unit connected to a drive shaft of a drive unit,
wherein the first shaft unit includes:
a first shaft connected to the drive shaft, the first shaft including a first shaft raceway surface that is formed by a groove extending in a circumferential direction on an outer peripheral surface of the first shaft;
a first output gear provided on the first shaft and configured to rotate integrally with the first shaft;
a first outer ring attached to a first support part supporting the first shaft and provided so as to surround the first shaft raceway surface, the first outer ring including a first outer ring raceway surface on an inner peripheral surface thereof; and
a plurality of ball-shaped first rolling elements disposed between the first shaft raceway surface and the first outer ring raceway surface,
wherein the groove forming the first shaft raceway surface has a pair of groove edge parts extending in the circumferential direction of the outer peripheral surface of the first shaft, wherein the groove edge part on a side closer to the first output gear has a diameter larger than a diameter of the other groove edge part, wherein the first rolling elements, the first shaft raceway surface, and the first outer ring raceway surface constitute a deep groove ball bearing, and wherein a load point between the first rolling element and the first shaft raceway surface and a load point between the first rolling element and the first outer ring raceway surface are positioned on a line perpendicular to the first shaft.

2 . The transmission according to claim 1 , wherein
the first shaft includes a raceway surface forming part that is a portion at which the first shaft raceway surface is provided, and an intermediate part that is a portion between the raceway surface forming part and the first output gear, and the intermediate part has an outer diameter larger than an outer diameter of the raceway surface forming part.

3 . The transmission according to claim 2 , wherein
a shape of the groove of the first shaft raceway surface in an axial direction of the first shaft is an arc shape along a raceway groove virtual circle, and the intermediate part and the first output gear do not interfere with the raceway groove virtual circle.

4 . The transmission according to claim 2 , wherein a gap having a predetermined reference length is provided between the first outer ring and the intermediate part in an axial direction of the first shaft.

5 . The transmission according to claim 1 , further comprising a retainer configured to retain each of the plurality of rolling elements in a freely rolling manner,
wherein the retainer protrudes outwards from an end of the first outer ring in an axial direction of the first shaft.

6 . The transmission according to claim 1 , wherein an O-ring disposed so as to surround the first outer ring is provided between an outer peripheral surface of the first outer ring and the first support part.

7 . The transmission according to claim 1 , wherein an outer peripheral surface of the first outer ring is provided with a coating having friction lower than friction of the outer peripheral surface of the first outer ring.

8 . The transmission according to claim 1 , further comprising a second shaft unit to which power is transmitted from the first shaft unit,
wherein the second shaft unit includes:
a second shaft including a second shaft raceway surface on an outer peripheral surface thereof;
a second input gear provided on the second shaft, wherein the second input gear meshes with the first output gear and is configured to rotate integrally with the second shaft;
a second output gear provided on the second shaft and configured to rotate integrally with the second shaft;
a second outer ring attached to a second support part supporting the second shaft and provided so as to surround the second shaft raceway surface, the second outer ring including a second outer ring raceway surface on an inner peripheral surface thereof; and
a plurality of second rolling elements disposed between the second shaft raceway surface and the second outer ring raceway surface, and
wherein a rotation axis of the first shaft and a rotation axis of the second shaft are parallel to each other.

9 . The transmission according to claim 8 , wherein at least one of a number of teeth of the first output gear, a number of the first rolling elements, a number of teeth of the second input gear, a number of teeth of the second output gear, and a number of the second rolling elements is a prime number.

10 . The transmission according to claim 8 , wherein
each of the second rolling elements is a tapered roller, the second shaft raceway surface has a truncated cone shape, and the second shaft is not provided with a small flange part adjacent to a small diameter side end of the second shaft raceway surface having the truncated cone shape.

11 . The transmission according to claim 8 , further comprising a differential gear unit to which power is transmitted from the second shaft unit,
wherein the differential gear unit includes:
a differential case including a third shaft raceway surface on an outer peripheral surface thereof;
a third input gear provided on the differential case, wherein the third input gear meshes with the second output gear and is configured to rotate integrally with the differential case;
a differential mechanism provided in the differential case;
a third outer ring attached to a third support part supporting the differential case and provided so as to surround the third shaft raceway surface, the third outer ring including a third outer ring raceway surface on an inner peripheral surface thereof; and
a plurality of third rolling elements disposed between the third shaft raceway surface and the third outer ring raceway surface, and
wherein the rotation axis of the second shaft and a rotation axis of the differential case are parallel to each other.

12 . The transmission according to claim 11 , wherein
each of the third rolling elements is a tapered roller, the third shaft raceway surface has a truncated cone shape, and the differential case is not provided with a small flange part adjacent to a small diameter side end of the third shaft raceway surface having the truncated cone shape.

13 . The transmission according to claim 11 , wherein at least one of a number of teeth of the first output gear, a number of the first rolling elements, a number of teeth of the second input gear, a number of teeth of the second output gear, a number of the second rolling elements, a number of teeth of the third input gear, and a number of the third rolling elements is a prime number.

14 . The transmission according to claim 1 , further comprising the drive unit,
wherein the drive unit includes:
a drive mechanism;
the drive shaft including a fourth shaft raceway surface on an outer peripheral surface thereof, wherein the drive shaft is rotationally driven by the drive mechanism and is connected to the first shaft;
a fourth outer ring attached to a fourth support part supporting the drive shaft and provided so as to surround the fourth shaft raceway surface, the fourth outer ring including a fourth outer ring raceway surface on an inner peripheral surface thereof; and
a plurality of fourth rolling elements disposed between the fourth shaft raceway surface and the fourth outer ring raceway surface.

15 . The transmission according to claim 14 , wherein at least one of a number of teeth of the first output gear

Assignees

• Nsk Ltd

Inventors

• NOMOTO Takahisa
• Nishii Hiroki
• Koshiba Yuki
• Yoshioka Hiroyasu
• Katou Hiroshi

Classifications

• F16C2361/61

  Toothed gear systems, e.g. support of pinion shafts · CPC title

• F16C33/585

  of raceways, e.g. ribs to guide the rollers · CPC title

• F16C35/077

  between housing and outer race ring · CPC title

• F16C33/66

  Special parts or details in view of lubrication · CPC title

• F16C19/36

  with a single row of rollers · CPC title