Motion Guide Displacement Absorbing Mechanism
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Solution Overview
Problem
Existing motion guide devices face challenges in accommodating large displacements due to thermal expansion differences between materials with varying thermal expansion coefficients, leading to reduced lifespan of rolling elements and difficulty in maintaining required rigidity ratios, especially in adverse environments with wide temperature variations.
Innovation Solution
A motion guide device with a displacement absorbing mechanism featuring a shear-deformable rubber layer and metal plate structure on the side surface of the moving block, allowing for adjustable rigidity in both vertical and horizontal directions by providing a space on the upper surface for displacement and integrating the rubber layer between the moving block and mounting member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large-size motion guide device with heavy rollers is selected to bear large displacement loads, then the rolling elements can withstand the load, but the device size and weight increase significantly
Solution Approach 1:
The displacement absorption function is segmented from the main motion guide structure. A separate displacement absorbing mechanism with elastic members is introduced to handle thermal expansion displacements, while the main motion guide structure focuses on precision guidance. This segmentation allows the use of lighter rolling elements since they no longer need to bear large displacement loads.
Solution Approach 2:
An intermediary displacement absorbing mechanism is introduced between the moving body and the base. This mechanism includes elastic members (such as springs or rubber elements) that absorb thermal expansion displacements before they are transmitted to the motion guide structure, thereby protecting the rolling elements from excessive loads.
2Adaptability or versatility
If movable-member mounting plates with thin portions are used to absorb displacement, then slight displacement can be absorbed elastically, but the flexibility is limited and large displacement cannot be absorbed
Solution Approach 1:
The elastic members in the displacement absorbing mechanism can be designed with adjustable parameters such as wire diameter, coil diameter, number of turns, and material properties. By changing these parameters, the mechanism can be tailored to absorb both slight and large displacements, making it suitable for various environments including those with wide temperature variations.
Solution Approach 2:
The displacement absorbing mechanism may combine different materials with complementary properties, such as using spring steel for the elastic members to provide both flexibility and strength, or combining metal springs with rubber elements to achieve non-linear elastic behavior that optimizes absorption across different displacement ranges.
3Device complexity
If the moving body is connected to the upper surface side of the moving block, then the structure is simple, but the vertical rigidity is high and cannot be reduced as required
Solution Approach 1:
The displacement absorbing mechanism is extracted from the main moving block structure and positioned separately. This allows the moving block to maintain its simple connection to the moving body while the separate displacement absorbing mechanism provides the required vertical compliance through its elastic members, effectively decoupling structural simplicity from rigidity control.
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 enhances the motion guide device's ability to absorb displacements, reducing vertical rigidity and increasing horizontal rigidity, thereby extending the lifespan of rolling elements and accommodating specific rigidity requirements, such as a lower vertical rigidity and higher horizontal rigidity.
Implementation Method 1
a displacement absorbing portion which is fixed to the mounting member and which is shear-deformed when the mounting member is displaced in a direction crossing an upper surface of the moving block
Implementation Method 2
integrating the rubber layer between the moving block and mounting member
Data Source
AI summary
Provided is a motion guide device having a low rigidity in the vertical direction and a low rigidity in the horizontal direction.The motion guide device has: a raceway rail 15 having a bottom surface 30a, side surfaces 30b and an upper surface 30c and being mounted on one of a base 12 and a moving body 11; and a moving block 16 having a center portion 16a facing the upper surface 30c of the raceway rail 15 and side wall portions 16b facing the side surfaces 30b of the raceway rail 15 and being mounted linearly or curvilinearly movable relative to the raceway rail 15. On a side surface of the moving block 16, a displacement absorbing mechanism 17, 38 is provided. The displacement absorbing mechanism 17, 38 has a mounting member 26, 34 mounted on an opposite one of the base 12 and the moving body 11, and a displacement absorbing portion 31, 37 which is fixed to the mounting member 26, 34 and which is shear-deformed when the mounting member 26, 34 is displaced in a direction crossing an upper surface of the moving block 16.