Link actuation device

Patent metadata

Field	Value
Publication number	US-9533420-B2
Application number	US-201514937117-A
Country	US
Kind code	B2
Filing date	Nov 10, 2015
Priority date	May 16, 2013
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

A distal end side link hub is connected to a proximal end side link hub via three or more link mechanisms such that alteration in posture of the distal end side link hub is allowed. Each of the link mechanisms includes a proximal side end link member, a distal side end link member, and an intermediate link member. A line member is disposed between the link hubs, two ends of the line member being held at line member holding points which are on link hub central axes, respectively. In a state where the link hubs are parallel to each other, when the distance from a midpoint to each spherical link center is defined as (D) and the distance from each spherical link center to its corresponding line member holding point is defined as (H), the relationship H=0.5×D is established.

First claim

What is claimed is:

1. A link actuation device comprising:
a proximal end side link hub; a distal end side link hub; and three or more link mechanisms which connect the distal end side link hub to the proximal end side link hub such that alteration in posture of the distal end side link hub is allowed,
wherein each of the link mechanisms includes: a proximal side end link member, one end of the proximal side end link member being rotatably connected to the proximal end side link hub; a distal side end link member, one end of the distal side end link member being rotatably connected to the distal end side link hub; and an intermediate link member whose two ends are rotatably connected to the other ends of the proximal side end link member and the distal side end link member, respectively,
wherein each of the link mechanisms has such a shape that a geometric model of the link mechanism depicted in straight lines shows symmetry between a proximal end side portion thereof and a distal end side portion thereof with respect to an intermediate portion of the intermediate link member,
wherein central axes of revolute pairs between the proximal end side link hub and the proximal side end links cross each other at a proximal end side spherical link center, and central axes of revolute pairs between the distal end side link hub and the distal side end links cross each other at a distal end side spherical link center,
wherein the link actuation device includes:
in a state where the proximal end side link hub and the distal end side link hub are parallel to each other,
a proximal end side link hub central axis being an axis that extends through the spherical link center of the proximal end side link hub toward the spherical link center of the distal end side link hub;
a distal end side link hub central axis being an axis that extends through the spherical link center of the distal end side link hub toward the spherical link center of the proximal end side link hub;
a proximal end side line member holding point which is on the proximal end side link hub central axis and which is located on a farther side from the distal end side spherical link center relative to the proximal end side spherical link center; and
a distal end side line member holding point which is on the distal end side link hub central axis and which is located on a farther side from the distal end side spherical link center relative to the proximal end side spherical link center,
wherein a line member is disposed between the proximal end side link hub and the distal end side link hub, two ends of the line member being held at the proximal end side line member holding point and the distal end side line member holding point,
wherein in a state where the proximal end side link hub and the distal end side link hub are parallel to each other, when a distance from a midpoint of the proximal end side spherical link center and the distal end side spherical link center to each of the spherical link centers is defined as D, and a distance from the proximal end side spherical link center to the proximal end side line member holding point and a distance from the distal end side spherical link center to the distal end side line member holding point are each defined as H,
the relationship
H= 0.5 ×D

is established.

2. The link actuation device as claimed in claim 1 , wherein
when a minimum bending radius of the line member is defined as Rmin, and a maximum bending angle of the distal end side link hub central axis relative to the proximal end side link hub central axis is defined as (2×θmax),
the relationship
R min= D ×(1/sin θmax+1/(2×tan θmax))

is established.

3. The link actuation device as claimed in claim 1 , wherein
the line member is an optical fiber.

4. The link actuation device as claimed in claim 1 , wherein
the line member is a flexible shaft capable of transmitting torque, one end of the line member being connected to an output shaft of a rotation actuator installed in the proximal end side link hub, the other end of the line member being connected to a rotation axis portion of a rotatable mount which is rotatably installed on the distal end side link hub.

Assignees

• Sone Keisuke
• Isobe Hiroshi
• Nishio Yukihiro
• Ntn Toyo Bearing Co Ltd

Inventors

• Sone Keisuke
• Isobe Hiroshi
• Nishio Yukihiro

Classifications

• B25J19/0025

  Means for supplying energy to the end effector · CPC title

• B25J9/0048 Primary

  with kinematics chains of the type rotary-rotary-rotary · CPC title

• B25J17/00 Primary

  Joints · CPC title