Parallel Link Robot Ball Spline Power Transmission
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Solution Overview
Problem
Existing parallel link robots face challenges in maintaining precise positioning and orientation of attached elements due to dimensional errors, mounting errors, and wear from friction in the power transmission mechanisms, which affect processing and assembly accuracy.
Innovation Solution
The implementation of a ball spline power transmission shaft with a meshing spline shaft and nut, supported by a universal joint, allows for smooth torque transmission and adjustment of the distance between auxiliary links and universal joints, reducing friction and maintaining parallel relationships between passive links, thereby enhancing positional and orientational accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a power transmission shaft with key shaft or spline shaft is used to transmit rotational driving force, then the additional actuator can drive the orientation changing mechanism, but dimensional errors and mounting errors accumulate, reducing positioning and orientation accuracy
Solution Approach 1:
The patent replaces the traditional key shaft or spline shaft mechanical power transmission system with a magnetic coupling system. The magnetic coupling transmitter and receiver use magnetic fields to transmit rotational driving force without mechanical contact, thereby eliminating dimensional error accumulation and mounting errors that occur in mechanical systems. This substitution maintains power transmission capability while significantly improving positioning and orientation accuracy.
2Adaptability or versatility
If a universal joint is used to connect the power transmission shaft to the input shaft, then flexibility in connection is achieved, but friction and wear occur, reducing reliability over time
Solution Approach 1:
The patent eliminates the universal joint from the power transmission path by using magnetic coupling for torque transmission. The magnetic coupling system allows for flexible connection between the additional actuator and orientation changing mechanism without the friction and wear inherent in universal joints. This non-contact magnetic transmission maintains connection flexibility while significantly improving operational reliability by removing wear-prone mechanical components.
3Device complexity
If traditional power transmission mechanisms are used, then structural simplicity is maintained, but friction causes wear and reduces positioning accuracy
Solution Approach 1:
The patent replaces traditional mechanical power transmission mechanisms (key shafts, spline shafts, universal joints) with a magnetic coupling system. While the magnetic coupling adds some structural elements, it eliminates multiple mechanical connection points and reduces overall mechanical complexity by removing friction-based components. The positioning accuracy improves significantly because the magnetic coupling transmits torque without contact, eliminating wear and friction-induced positioning errors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables precise three-dimensional positioning and orientation of the wrist portion with reduced wear and increased accuracy, allowing for reliable operation despite potential errors in component alignment.
Implementation Method 1
the power transmission shaft portion includes a ball spline in which a spline shaft and a nut are meshed with each other
Implementation Method 2
the spline shaft being fixed to one of a universal joint attached to an input shaft of the additional mechanism portion
Data Source
AI summary
A parallel link robot includes: a base portion; a movable portion; arms that connect the base portion and the movable portion in parallel; base actuators that are disposed on the base portion and that drive the respective arms; an additional actuator that drives an additional mechanism portion attached to the movable portion; an auxiliary link that pivotally connects the additional actuator to at least one of the arms; and a power transmission shaft portion that transmits a rotational driving force of the additional actuator to the additional mechanism portion. Each of the arms includes a drive link and two passive links. The auxiliary link bridges the two passive links and is pivotally connected to each of the two passive links. The power transmission shaft portion includes a ball spline in which a spline shaft and a nut are meshed with each other.