Gear mechanism, speed reducer, and robot arm

Patent metadata

Field	Value
Publication number	US-9427866-B2
Application number	US-201314422881-A
Country	US
Kind code	B2
Filing date	Sep 20, 2013
Priority date	Sep 25, 2012
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

A gear mechanism, including: a first gear; and a second gear. The first gear and the second gear are arranged at an inclination angle to form a first meshing region and a second meshing region. Multiple tooth tip portions of the first gear and multiple tooth tip portions of the second gear are each formed to be held in contact with each other at one point in the first meshing region. Multiple recessed portions of the first gear and multiple recessed portions of the second gear are each formed to conform to a passing region extending along movement of one of the multiple mating tooth tip portions at the time of moving in the second meshing region.

First claim

The invention claimed is:

1. A gear mechanism, comprising:
a first gear having an annular tooth surface comprising:
multiple tooth tip portions formed on a distal end side with respect to a predetermined height; and
multiple recessed portions formed on a tooth root side with respect to the predetermined height at positions between the multiple tooth tip portions, respectively; and

a second gear having an annular tooth surface comprising:
multiple tooth tip portions formed on a distal end side with respect to the predetermined height; and
multiple recessed portions formed on a tooth root side with respect to the predetermined height at positions between the multiple tooth tip portions, respectively,
the multiple tooth tip portions of the second gear and the multiple recessed portions of the second gear being respectively larger in number than the multiple tooth tip portions of the first gear and the multiple recessed portions of the first gear,

wherein the first gear and the second gear are arranged under a state in which a rotation axis of the first gear and a rotation axis of the second gear are inclined at a predetermined angle so as to set a deepest meshing position at which one of the multiple tooth tip portions of one of the first gear and the second gear and corresponding one of the multiple recessed portions of another of the first gear and the second gear mesh most deeply with each other, and a grazing position at which the one of the multiple tooth tip portions of the one of the first gear and the second gear and corresponding one of the multiple tooth tip portions of the another of the first gear and the second gear graze each other on an opposite side of the deepest meshing position, and to form a first meshing region in which the one of the multiple tooth tip portions of the one of the first gear and the second gear and the corresponding one of the multiple tooth tip portions of the another of the first gear and the second gear are held in contact with each other on each of both sides of the grazing position, and a second meshing region in which the one of the multiple tooth tip portions of the one of the first gear and the second gear and the corresponding one of the multiple recessed portions of the another of the first gear and the second gear are held in contact with each other on the deepest meshing position side with respect to the first meshing region,
wherein the multiple tooth tip portions of the first gear and the multiple tooth tip portions of the second gear are each formed to be held in contact with each other at one point in the first meshing region, and
wherein the multiple recessed portions of the first gear and the multiple recessed portions of the second gear are each formed to conform to a passing region extending along movement of one of the multiple mating tooth tip portions at the time of moving in the second meshing region.

2. A gear mechanism according to claim 1 , wherein the multiple tooth tip portions of the first gear and the multiple tooth tip portions of the second gear are each formed based on the following expressions assuming an X-Yp-Zp coordinate system and an X-Yq-Zq coordinate system including:
a Zp-axis corresponding to a rotation axis of the first gear;
a Zq-axis corresponding to a rotation axis of the second gear;
an origin O corresponding to an intersection between the Zp-axis and the Zq-axis;
a common X-axis orthogonal to a plane including the Zp-axis and the Zq-axis;
a Yp-axis orthogonal to the Zp-axis and the common X-axis; and
a Yq-axis orthogonal to the Zq-axis and the common X-axis,
yp=R tan(η/2)cos( xpZ ) and yq=−R tan(η/2)cos( xq ( Z+n ))

where R represents a radius of each of the first gear and the second gear, 11 represents an inclination angle of the Zq-axis with respect to the Zp-axis, Z represents a number of teeth of the first gear, and Z+n represents a number of teeth of the second gear.

3. A gear mechanism according to claim 2 , wherein the multiple tooth tip portions of the first gear and the multiple tooth tip portions of the second gear are formed to have respective distal ends that are held in contact with each other at the grazing position.

4. A gear mechanism according to claim 2 , wherein the multiple tooth tip portions of the first gear and the multiple tooth tip portions of the second gear are trimmed to have respective distal ends that are out of contact with each other at the grazing position.

5. A gear mechanism according to claim 2 , wherein a difference n in number of teeth between the first gear and the second gear is one of one and two.

6. A speed reducer, comprising at least one pair of the gear mechanisms according to claim 1 , the speed reducer being configured to output an input rotation at a lower speed.

7. An articulated robot arm, comprising:
at least one joint; and
an actuator comprising:
a drive motor; and
the speed reducer according to claim 6 , which is connected to the drive motor,
the actuator being mounted to the at least one joint.

Assignees

• Canon Kk

Inventors

• Hasegawa Masahide

Classifications

• Y10S901/25

  Gearing · CPC title

• B25J9/102 Primary

  Gears specially adapted therefor, e.g. reduction gears (gearings in general F16H) · CPC title

• F16H1/321

  the orbital gear being nutating · CPC title

• B25J9/104 Primary

  with cables, chains or ribbons · CPC title

• Y10T74/1966

  Intersecting axes · CPC title