Link Actuating Device Bearing Grease Circulation Control
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Solution Overview
Problem
Existing parallel link mechanisms face challenges in achieving a compact size while maintaining a wide operating range and long bearing life, as increased link length leads to bulkiness and reduced rigidity, and current configurations with oscillating revolute pairs shorten bearing lifespan.
Innovation Solution
A link actuating device with three or more trinodal chain link mechanisms, featuring symmetric geometric models and actuators to alter posture, includes bearings in revolute pairs for reduced friction and a grease circulation control system to extend bearing life, allowing for a ±90° bending angle and 360° traverse angle, ensuring smooth operation and long bearing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If link length is increased to expand operating range, then operating range is improved, but device size increases and rigidity decreases
Solution Approach 1:
The patent changes the operating parameters of the bearing by controlling the oscillation angle of the revolute pair to remain within a specific range (within 90 degrees). This parameter control allows the mechanism to achieve a wide operating range without requiring increased link length, thereby maintaining compact device size while expanding operational capability.
2Adaptability or versatility
If link length is increased to expand operating range, then operating range is improved, but rigidity decreases
Solution Approach 1:
The patent maintains rigidity by controlling the oscillation angle parameter within 90 degrees, which prevents excessive deformation of the link members. This parameter control allows the mechanism to achieve wide operating range without compromising structural rigidity, eliminating the need to increase link length for expanded functionality.
3Adaptability or versatility
If revolute pair oscillates to enable posture alteration, then adaptability is improved, but bearing life decreases
Solution Approach 1:
The patent changes the operating parameter of the bearing by limiting the oscillation angle of the revolute pair to within 90 degrees. This parameter control prevents the bearing from operating in unfavorable conditions that would reduce its life, while still allowing sufficient posture alteration capability for the mechanism to function effectively.
Solution Approach 2:
The patent implements control based on feedback regarding the oscillation angle of the revolute pair. By monitoring and controlling this parameter to remain within the acceptable range, the system ensures optimal bearing life while maintaining the necessary adaptability for posture changes during operation.
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
The device achieves a compact, two-degrees-of-freedom mechanism with a wide operating range and extended bearing life by reducing friction and preventing poor lubrication through controlled grease circulation, maintaining the bearing within its oscillation range.
Implementation Method 1
a bearing 12, 19 being interposed in each of the revolute pairs; wherein a maximum value of a bending angle, in the work-time control, being an angle between a central axis of the proximal end side link hub 2 and a central axis of the distal end side link hub 3 does not exceed a maximum allowable bending angle being a maximum value of the bending angle allowable in each mechanism, and a maximum value of the bending angle in the grease circulation control is greater than the maximum value of the bending angle in the work-time control and smaller than the maximum allowable bending angle
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A bearing is interposed in the revolute pair between a proximal end side link hub (2) and each proximal side end link member (5). A control device controls an actuator, to perform work-time control for causing a determined work operation to be executed and to perform, while the work-time control is stopped, grease circulation control for circulating grease sealed in the bearing. The maximum value θmax of a bending angle in the work-time control does not exceed the maximum allowable bending angle θ'max being the maximum value of the bending angle allowable in the mechanism, and the maximum value of the bending angle in the grease circulation control is greater than the maximum value θmax of the bending angle in the work-time control and smaller than the maximum allowable bending angle θ'max.