Linear Guide Preload Adjustment for Straightness Without Grinding
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Solution Overview
Problem
Heat treatment of guide members in linear guide mechanisms often leads to distortion and reduced straightness, necessitating additional processing like grinding to improve alignment, and existing solutions fail to effectively manage increased pre-loading of balls without increasing sliding resistance.
Innovation Solution
A linear guide mechanism with heat-treated steel guide members and a pressing mechanism using set screws to adjust pre-loading and improve straightness, eliminating the need for grinding and minimizing sliding resistance by arranging balls in two rows between guide members in a circular arc configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heat treatment is performed on guide members to increase hardness, then the rolling surfaces become harder and more durable, but distortion occurs and straightness is lowered
Solution Approach 1:
The guide member is divided into two parts: the main body (which undergoes heat treatment for hardness) and the rolling surface portion (which requires high straightness). The rolling surface portion is formed separately with high precision and then integrated with the heat-treated main body, allowing each part to be optimized independently for its specific function.
Solution Approach 2:
Different parts of the guide member have different quality requirements. The main body requires high hardness for durability, while the rolling surface portion requires high straightness for precision. By applying heat treatment only to the main body and forming the rolling surface portion separately with precise machining, each local area achieves its optimal quality characteristics without compromising the other.
2Manufacturing precision
If pre-loading of balls is increased to eliminate rattling and backlash, then guidance accuracy improves, but sliding resistance increases
Solution Approach 1:
The guide members and balls are designed with circular arc geometries that create optimal contact points. The curved surfaces allow the balls to roll efficiently while maintaining appropriate pre-loading, reducing sliding resistance compared to flat-surface designs that require higher pre-loading to achieve the same guidance accuracy.
Solution Approach 2:
The curvature radius of the circular arcs is carefully selected to optimize the balance between pre-loading and sliding resistance. By adjusting the curvature parameter, the design achieves sufficient guidance accuracy through geometric constraints rather than relying solely on increased ball pre-loading, thereby minimizing sliding resistance.
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 mechanism effectively improves straightness without grinding and suppresses increased sliding resistance, ensuring reliable operation by adjusting ball pre-loading through set screws, thus addressing distortion and alignment issues.
Implementation Method 1
a pressing mechanism configured to adjust a pre-loading of the balls and improve straightness of the moving block side guide members, is attached to the moving block. Set screws are used as the pressing mechanism.
Implementation Method 2
a plurality of balls disposed in two rows, respectively, between the actuator side guide member and each of the moving block side guide members
Implementation Method 3
there are cases in which a heat treatment (quenching/tempering) is carried out on the molded products serving as the guide members. In this case, due to the heat treatment, distortion occurs and straightness is lowered.
Data Source
AI summary
A linear guide mechanism includes an actuator side guide member, moving block side guide members disposed on both sides of the actuator side guide member, and a plurality of balls disposed in two rows, respectively, between the actuator side guide member and each of the moving block side guide members. Set screws are attached to a moving block.