Eccentric Oscillating Gear Phase Alignment for Robot Joints

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Solution Overview

Problem

The existing eccentric oscillating gear devices for robot arms suffer from variations in torsional rigidity phase during rotation due to unrestricted eccentric direction assembly, leading to phase changes when disassembled and reassembled, and individual differences in phase between gear devices.

Innovation Solution

The eccentric oscillating gear device incorporates rotational phase adjusting means, comprising reference portions on the outer cylinder, carrier, and spur gear, to set the crankshaft's orientation based on the orientations of these components, ensuring consistent assembly and reducing torsional rigidity variations by aligning the outer cylinder, carrier, and crankshaft correctly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the crankshaft is assembled to the carrier without restriction in terms of eccentric direction, then the assembly process is simple and easy to manufacture, but the phase of torsional rigidity in rotation direction changes when disassembled and reassembled, and individual differences occur between multiple gear devices

Engineering Contradiction:
Improveassembly processVSAvoidphase of torsional rigidity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-setting the eccentric direction of the crankshaft relative to the carrier through rotational phase adjusting means before final assembly. This preliminary orientation setting ensures that when the gear device is disassembled and reassembled, the crankshaft automatically returns to its original rotational phase, maintaining consistent torsional rigidity characteristics and eliminating individual differences between multiple gear devices while keeping the assembly process simple.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If rotational phase adjusting means is added to set the orientation of the crankshaft, then the phase of torsional rigidity is stabilized and individual differences are eliminated, but the device complexity increases

Engineering Contradiction:
Improvephase of torsional rigidityVSAvoidstructure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies self-service by designing the rotational phase adjusting means as a self-aligning mechanism that automatically maintains the crankshaft's rotational phase without requiring external adjustment devices or complex control systems. The mechanism uses the existing assembly structure to provide self-positioning functionality, stabilizing the torsional rigidity phase while minimizing additional complexity in the overall device structure.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2708772B1Robot
Publication Date: 2019.01.09 NABTESCO CORP
  • EP2708772B1 patent drawingFigure 1
  • EP2708772B1 patent drawingFigure 2
  • EP2708772B1 patent drawingFigure 3

AI summary

The present application relates to a robot, comprising: a first member (20); a second member (38); a speed reducer (10) for use in an articulated joint between the first member (20) and the second member (38) to transmit driving force while changing a rotation speed at a given rotation speed ratio, in which an externally toothed gear (48a, 48b) is rotated with being meshed internal teeth; and a rotational phase adjusting means (58) capable of adjusting rotational phase of the speed reducer (10) so that the rotational phase of the speed reducer (10) is set to be a given rotational phase when an orientation of the second member (38) with respect to an orientation of the first member (20) is set to a given orientation.