Robot Joint Gear Structure With Radial Backlash Adjustment
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Solution Overview
Problem
In industrial robots, backlash in the joint shafts, especially those distant from the robot tip, significantly affects trajectory accuracy, and existing methods struggle to adjust backlash between the motor-side gear and the mating gear due to the fixed position of the rotational shaft by auxiliary bearings.
Innovation Solution
A robot joint structure that includes a motor, a motor-side gear, an auxiliary bearing, and an adapter that integrates these components, with a moving mechanism allowing the unit structure to move radially, enabling the motor-side gear to approach the mating gear and reduce backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an auxiliary bearing is mounted to support the motor shaft, then the load on the motor shaft is reduced and rigidity is ensured, but the position of the rotational shaft is fixed and backlash adjustment becomes difficult
Solution Approach 1:
The patent divides the bearing support system into two segments: a main bearing that provides primary support and an auxiliary bearing that provides supplemental support. This segmentation allows the auxiliary bearing to reduce shaft deflection and improve rigidity without completely constraining the shaft's axial movement capability, enabling backlash adjustment while maintaining structural strength.
Solution Approach 2:
The patent introduces a dynamic adjustment mechanism that allows the motor shaft to move axially relative to the gear when needed for backlash adjustment, while the auxiliary bearing maintains its supplemental support function. This dynamic capability enables the system to transition between a constrained state (for rigidity) and an adjustable state (for backlash reduction).
2Manufacturing precision
If the motor shaft is extended to reduce the distance from motor to speed reduction gear, then trajectory accuracy improves, but the load on the motor shaft increases and auxiliary bearing becomes necessary
Solution Approach 1:
The auxiliary bearing acts as an intermediary element between the motor shaft and the housing. It provides supplemental support to the extended motor shaft, distributing the load and reducing bending moments without interfering with the shaft's rotational function or the gear meshing operation.
3Manufacturing precision
If backlash is not reduced in joint shafts distant from robot tip, then device complexity remains low, but robot trajectory accuracy degrades
Solution Approach 1:
The auxiliary bearing serves multiple functions: it provides supplemental shaft support to improve rigidity, enables backlash adjustment capability, and maintains structural integrity. This multi-functionality allows the system to achieve trajectory accuracy improvement without adding dedicated backlash adjustment mechanisms, thereby limiting the increase in device complexity.
Data Source
AI summary
A robot joint structure includes a motor configured to be used for a robot joint shaft capable of turning about a vertical axis, a motor-side gear mounted on a shaft of the motor, an auxiliary bearing configured to axially support the shaft supplementally, an adapter configured to integrate the motor, the motor-side gear, and the auxiliary bearing, and a moving mechanism configured to move a unit structure integrated by the adaptor in a radial direction of the motor such that the motor-side gear approaches a mating gear meshing with the motor-side gear.