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US 11,378,170 B2Granted
Gear device and robot
AssigneeSeiko Epson Corporation
InventorYoichi Noda
Life of this patent
Estimating the term…
Abstract
A gear device includes an internal gear, a flexible external gear, and a wave generator. The wave generator has an elliptic cam and a bearing. An inner ring has an inner ring raceway surface which a plurality of balls are in contact with, and a pair of inner ring shoulder parts. At a position of a minor axis, a first inner ring shoulder part has a greater height than a second inner ring shoulder part. At a position of a major axis, the second inner ring shoulder part has a greater height than the first inner ring shoulder part.
Claims7
A gear device comprising:
- an internal gear;
- a flexible external gear partly meshing with the internal gear and rotating relative to the internal gear about a rotation axis;
- and
- a wave generator being in contact with an inner circumferential surface of the external gear and moving a meshing position between the internal gear and the external gear in a circumferential direction about the rotation axis, wherein
- the wave generator has a cam having an elliptic outer circumferential surface having a major axis and a minor axis, and a bearing arranged between the inner circumferential surface of the external gear and the outer circumferential surface of the cam,
- the bearing has an inner ring, an outer ring, and a plurality of balls arranged between the inner ring and the outer ring,
- the inner ring has an inner ring raceway surface which the plurality of balls are in contact with, and a pair of inner ring shoulder parts adjacent to the inner ring raceway surface and protruding toward the outer ring as viewed in a cross section including the rotation axis,
- the external gear has a first end part opening in a direction along the rotation axis, and a second end part opposite to the first end part,
- the wave generator is fitted in the inner circumferential surface of the external gear at a position closer to the first end part than to the second end part of the external gear,
- the pair of inner ring shoulder parts include a first inner ring shoulder part closer to the first end part than to the second end part, and a second inner ring shoulder part closer to the second end part than to the first end part, and
- at a position of the minor axis, the first inner ring shoulder part has a greater height than the second inner ring shoulder part, and at a position of the major axis, the second inner ring shoulder part has a greater height than the first inner ring shoulder part.
8 more elements
A robot comprising:
- a first member forming a base or an arm;
- a second member forming an arm provided in such a way as to be able to swivel in relation to the first member;
- and
- a gear device transmitting a drive force from one of the first member and the second member toward the other, wherein
- the gear device has
- an internal gear,
- a flexible external gear partly meshing with the internal gear and rotating relative to the internal gear about a rotation axis, and
- a wave generator being in contact with an inner circumferential surface of the external gear and moving a meshing position between the internal gear and the external gear in a circumferential direction about the rotation axis,
- the wave generator has a cam having an elliptic outer circumferential surface having a major axis and a minor axis, and a bearing arranged between the inner circumferential surface of the external gear and the outer circumferential surface of the cam,
- the bearing has an inner ring, an outer ring, and a plurality of balls arranged between the inner ring and the outer ring,
- the inner ring has an inner ring raceway surface which the plurality of balls are in contact with, and a pair of inner ring shoulder parts adjacent to the inner ring raceway surface and protruding toward the outer ring as viewed in a cross section including the rotation axis,
- the external gear has a first end part opening in a direction along the rotation axis, and a second end part opposite to the first end part,
- the wave generator is fitted in the inner circumferential surface of the external gear at a position closer to the first end part than to the second end part of the external gear,
- the pair of inner ring shoulder parts include a first inner ring shoulder part closer to the first end part than to the second end part, and a second inner ring shoulder part closer to the second end part than to the first end part, and
- at a position of the minor axis, the first inner ring shoulder part has a greater height than the second inner ring shoulder part, and at a position of the major axis, the second inner ring shoulder part has a greater height than the first inner ring shoulder part.
12 more elements
Dependencies are inferred from the claim text.