Robot Joint Speed Reducer Fixing to Protect Gear Meshing
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Solution Overview
Problem
The existing robot joint structures face issues with radial loads affecting the meshing between internal and external gears when a speed reducer is fixed to a robot member in a radial direction, leading to adverse effects on gear meshing.
Innovation Solution
A robot joint structure design that includes a speed reducer with a non-rotatable fixing member relative to the internal gear, fixed to the robot member using a fastening member, where the axial range of the fastening member does not overlap the internal gear teeth, reducing the impact of radial loads on gear meshing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a part of the speed reducer and the first robot member are brought into pressure contact with each other in a radial direction, then the fixing strength is improved, but the meshing between internal gear and external gear is adversely affected
Solution Approach 1:
The patent transitions from radial direction fastening to axial direction fastening. The fastening member is configured to apply clamping force in the axial direction rather than the radial direction, thereby avoiding the generation of radial loads that would interfere with gear meshing while still achieving secure fixation of the speed reducer to the robot member
Solution Approach 2:
Instead of fastening the speed reducer from the radial direction (conventional approach), the patent inverts the fastening direction to apply force from the axial direction. This inversion allows the fastening member to clamp the speed reducer housing without creating radial loads on the gear components
2Volume of moving object
If the outer diameter of robot members is reduced, then the size and weight are decreased, but the structural integrity and load-bearing capacity are compromised
Solution Approach 1:
The patent changes the fastening direction parameter from radial to axial, which fundamentally alters the load transmission path. This parameter change allows for more efficient stress distribution that maintains structural integrity even with reduced outer dimensions
Data Source
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AI summary
Provided is a technique capable of suppressing an adverse effect on meshing between an internal gear (32, 33) and an external gear (30) when a part of a speed reducer (20) and a first robot member (14) are brought into pressure contact in a radial direction. A robot joint structure (10) includes a first robot member (14), a second robot member (16), and a speed reducer (20) incorporated in a joint portion (18) that connects the first robot member (14) and the second robot member to each other. The speed reducer 20 includes an external gear (30), an internal gear (32, 33) that meshes with the external gear, and a fixing member (34) that is provided so as to be non-rotatable relative to the internal gear (32, 33) and is fixed to the first robot member (14). The fixing member (34) is fixed to the first robot member (14) by bringing an inner peripheral surface of the first robot member (14) and an outer peripheral surface of the fixing member (34) into pressure contact with each other by fastening using the first fastening member (B1). At least a part of an axial range A1 of the first fastening member (B1) does not overlap internal teeth (32b, 33b) of the internal gear (32, 33) when viewed in a radial direction.