JP-7855605-B2 - Joint structure, robot and robot joint structure

JP7855605B2JP 7855605 B2JP7855605 B2JP 7855605B2JP-7855605-B2

Inventors

松尾雄希

Assignees

東京ロボティクス株式会社

Dates

Publication Date: 20260508
Application Date: 20211111

Claims (15)

The first link, A second link is supported by the first link so as to be rotatable around a first axis and bends relative to the first link, A third link is supported by the second link so as to be rotatable around a second axis which is substantially perpendicular to or parallel to the first axis, and pivots relative to the second link, A first motor is provided on the first link and causes the second link to rotate around the first axis, The system includes a second motor provided on the second link, which causes the third link to rotate around the second axis, The drive shaft of the second motor coincides substantially with the first shaft. The second link is supported to the first link via two pivot support members, the first and second pivot support members being arranged parallel to each other so as to share a common central axis, forming an articulated structure.
The system further includes a second reduction gear provided on the power transmission path between the second motor and the third link, which reduces the output of the second motor. The articulated structure according to claim 1, wherein the second reduction gear includes a three-stage orthogonal reduction gear.
The articulated structure according to claim 2, wherein the orthogonal reduction gear includes at least a second hypoid mechanism comprising a second pinion gear and a second ring gear.
The joint structure according to claim 3, wherein the shortest distance between the extension line of the first axis and the extension line of the second axis coincides with the offset amount of the second pinion gear from the center of the second ring gear.
The orthogonal reduction gear, in the power transmission path from the second motor to the third link, sequentially includes a first bevel gear mechanism comprising a pair of bevel gears, a second hypoid gear mechanism comprising a second pinion gear and a second ring gear, and a second bevel gear mechanism comprising a pair of bevel gears, as described in claim 2.
The system further includes a first reduction gear provided on the power transmission path between the first motor and the second link, which reduces the output of the first motor. The articulated structure according to any one of claims 1 to 5, wherein the first reduction gear includes a first hypoid mechanism comprising a first pinion gear and a first ring gear.
The first reduction gear includes, in order, a first transmission mechanism that transmits the output of the first reduction gear and a first hypoid mechanism along a power transmission path from the first motor to the second link, The joint structure according to claim 6, wherein the drive shaft of the first motor is parallel to the rotational center axis of the first pinion gear.
The joint structure according to claim 7, wherein the first transmission mechanism is a pulley mechanism consisting of a pair of pulleys and a belt.
The joint structure according to claim 7, wherein the first transmission mechanism is a spur gear mechanism consisting of a plurality of spur gears.
The encoder further comprises an encoder disk and a reading board for reading the encoder disk, The joint structure according to any one of claims 1 to 9, wherein one of the encoder disk and the reading board is provided on the second motor, and the other is provided on the first link.
The second motor is positioned between the first rotation support member and the second rotation support member. A first space is located on the drive shaft of the second motor, on the output shaft side of the second motor and on the rear side of the first pivot support member as viewed from the second motor; on the other hand, a second space is located on the drive shaft of the second motor, on the opposite side of the output shaft of the second motor and on the rear side of the second pivot support member as viewed from the second motor. The joint structure according to claim 1, wherein a part of a mechanism for transmitting driving force from the second motor to the third link is arranged in the first space, and a drive board for driving the first motor and/or the second motor is arranged in the second space.
The joint structure according to claim 11 , wherein the appearance of the first link, the second link, and the third link is configured to be symmetrical.
The first link, A second link is supported by the first link so as to be rotatable around a first axis and bends relative to the first link, A third link is supported by the second link so as to be rotatable around a second axis which is substantially perpendicular to or parallel to the first axis, and pivots relative to the second link, A first motor is provided on the first link and causes the second link to rotate around the first axis, A second motor is provided on the second link, which causes the third link to rotate around the second axis, A first reduction gear is provided on the power transmission path between the first motor and the second link, and reduces the output of the first motor. The system includes a second reduction gear, which is provided on the power transmission path between the second motor and the third link and reduces the output of the second motor, The drive shaft of the second motor is substantially aligned with the first shaft. The first reduction gear includes a first hypoid mechanism consisting of a first pinion gear and a first ring gear. The second reduction gear includes a three-stage orthogonal reduction gear, The orthogonal reduction gear includes at least a second hypoid mechanism consisting of a second pinion gear and a second ring gear. The second link is supported to the first link via two pivot support members, the first and second pivot support members being arranged parallel to each other so as to share a common central axis, forming an articulated structure.
The first link, A second link is supported by the first link so as to be rotatable around a first axis and bends relative to the first link, A third link is supported by the second link so as to be rotatable around a second axis which is substantially perpendicular to or parallel to the first axis, and pivots relative to the second link, A first motor is provided on the first link and causes the second link to rotate around the first axis, The system includes a second motor provided on the second link, which causes the third link to rotate around the second axis, The drive shaft of the second motor is substantially aligned with the first shaft. A robot with an articulated structure, wherein the second link is supported to the first link via two rotational support members, the first rotational support member and the second rotational support member being arranged parallel to each other so as to share a common central axis .
The first link, A second link is supported by the first link so as to be rotatable around a first axis and bends relative to the first link, A third link is supported by the second link so as to be rotatable around a second axis which is substantially perpendicular to or parallel to the first axis, and pivots relative to the second link, A first motor is provided on the first link and causes the second link to rotate around the first axis, The system includes a second motor provided on the second link, which causes the third link to rotate around the second axis, The drive shaft of the second motor coincides substantially with the first shaft. The robot joint structure wherein the second link is supported to the first link via two rotational support members, the first rotational support member and the second rotational support member being arranged parallel to each other so as to share a common central axis .

Description

This invention relates to a joint structure or a robot equipped with a joint structure. Robot arms and the like are known that have joint structures that allow rotation around an axis perpendicular or nearly perpendicular to the longitudinal axis of the link or the axis extending from the base to the tip of the link (hereinafter, this rotation may simply be referred to as bending), and also around the longitudinal axis of the link or the axis extending from the base to the tip of the link or an axis parallel thereto (hereinafter, this rotation may simply be referred to as swivel). This type of robot can perform a variety of tasks by taking advantage of its degrees of freedom. For example, Patent Document 1 discloses a wrist drive structure for an industrial robot capable of bending (pivoting around the second axis b) and swiveling (pivoting around the third axis c). Patent No. 4233578 Figure 1 is a perspective view of the elbow joint of a robotic arm.Figure 2 is a transparent perspective view showing the internal structure of the upper arm linkage.Figure 3 is a perspective view showing the internal structure of the upper arm linkage.Figure 4 is a schematic diagram illustrating the principle of transmission of rotational driving force from the first motor.Figure 5 is a transparent perspective view showing the internal structure of the first forearm linkage.Figure 6 is a perspective view showing the internal structure of the first forearm linkage.Figure 7 is a schematic diagram illustrating the principle of transmission of rotational driving force from the second motor.Figure 8 is a schematic diagram illustrating the principle of a joint structure that provides flexion and rotation.Figure 9 is a front view of the robot arm.Figure 10 is a perspective view of the robot arm as seen from the front.Figure 11 is a conceptual diagram showing a part of the internal structure of the elbow portion of a robot arm, viewed from the side.Figure 12 shows a modified example of the configuration for transmitting the rotational driving force of the second motor. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. (1. First Embodiment) As a first embodiment, an example in which the joint structure according to the present invention is applied to the elbow joints of a pair of left and right arms of a humanoid robot will be described. Note that the joint structure according to the present invention can be applied to any joint that requires flexion and rotation. Therefore, it can also be applied to joints other than the elbow joint, such as the shoulders and waist joints of a robot. In this embodiment, bending refers to rotation around an axis (bending axis) that is perpendicular or nearly perpendicular to the longitudinal axis of the link or the axis extending from the base to the tip of the link. Furthermore, rotation refers to rotation around the longitudinal axis of the link or the axis extending from the base to the tip of the link, or an axis parallel thereto. Figure 1 is an external perspective view of the elbow joint of a robot arm. As is clear from the figure, in this embodiment, the elbow joint of the robot arm comprises an upper arm link 1 (or first link) that constitutes the portion from the upper arm to the center of the elbow, a first forearm link 3 (or second link) that constitutes the portion from the sides of the elbow to the forearm, and a second forearm link 5 (or third link) that is positioned near the tip of the first forearm link 3 and provides a connection to other members at its tip. By the relative rotation of these links, bending or swiveling motions are achieved. More specifically, the lower end of the upper arm link 1 is provided with a first forearm link 3, which is connected to both sides of the upper arm link 1 in a double-support manner. The robot arm's bending motion is achieved by the rotation of these upper arm link 1 and first forearm link 3 around the A1 axis, which is depicted horizontally in the figure. A second forearm link 5 is provided at the lower end of the first forearm link 3, which rotates around an axis parallel to the longitudinal axis of the robot arm. The rotation of the robot arm is achieved by the rotation of these two links, the first forearm link 3 and the second forearm link 5, around the A2 axis, which is depicted vertically in the figure. Figures 2 and 3 illustrate the configuration related to rotation around the A1 axis, i.e., flexion. Figure 2 is a transmission perspective view showing the internal configuration of the upper arm link 1, and Figure 3 is a perspective view of the internal configuration of the upper arm link 1. As is clear from these figures, a cylindrical motor cover 11 is positioned at the upper center of the upper arm link 1, its position fixed by a motor support member 12. Inside the motor cover 11 are a first motor 111 (not shown) and an encoder 112 (not shown) for detecting th