Machine Tool Bearing Preload Structure for Uniform Force Distribution
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Solution Overview
Problem
Conventional bearing preload structures in machine tools face issues with non-uniform pressing force distribution around the ball bearing periphery, leading to spindle curvature and vibration problems, and are complex and costly to maintain due to the need for detachable components.
Innovation Solution
A bearing preload structure featuring a spindle with small-diameter, intermediate-diameter, and large-diameter portions, along with a flange member and collar member, ensures uniform pressing force distribution through precisely machined and polished surfaces, allowing for easy assembly and maintenance by eliminating the need for detachable nuts and motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If nut members and bearing pressings are used to fix ball bearings, then the bearing can be fixed to a fixed position, but the pressing force cannot act uniformly around the whole periphery of the ball bearings, causing spindle curvature and vibration
Solution Approach 1:
The invention divides the bearing fixation system into multiple independent bearing pressings distributed around the spindle periphery. Each bearing pressing independently applies force to the ball bearing, ensuring uniform distribution of pressing force around the entire circumference, thereby preventing spindle curvature and vibration.
Solution Approach 2:
The invention creates localized contact surfaces between each bearing pressing and the ball bearing, with precisely machined parallel end surfaces. This local quality enhancement ensures that each bearing pressing applies force uniformly at its specific location, and the combined effect of multiple such pressings achieves uniform force distribution around the entire bearing periphery.
2Ease of repair
If detachable nuts and special structures are employed to allow rotor detachment for bearing changes, then bearing replacement becomes possible, but the structure becomes complex, increasing cost
Solution Approach 1:
The invention extracts the bearing fixation function from complex detachable nut structures and implements it through simpler bearing pressings that are press-fitted into the spindle. This extraction maintains bearing replaceability while significantly reducing structural complexity by eliminating the need for multiple detachable components and special rotor detachment mechanisms.
Solution Approach 2:
The bearing pressings are designed as simple, inexpensive components that can be easily replaced when bearings need maintenance. Rather than designing for complex disassembly of permanent structures, the invention uses simple press-fit components that can be straightforwardly removed and replaced, reducing both initial complexity and maintenance complexity.
Data Source
AI summary
On an outer surface 2b of a spindle 2, a first end surface 2f abutting on one end surface 11d in an axial direction of an inner ring 11 of a first ball bearing 10 is formed so as to be positioned in a plane perpendicular to an axial center, and a second end surface 2c is formed so as to be parallel to the first end surface 2f and be positioned a predetermined distance t apart in the axial direction from the other end surface 11c′ in the axial direction of an inner ring 11′ of a second ball bearing 10′, and a flange member 17 is attachably/detachably fitted to the second end surface 2c so as to come into close contact with the second end surface 2c, and between the flange member 17 and the other end surface 11c′ of the inner ring 11′, a collar member 19 having an axial-direction dimension slightly longer than the predetermined distance t is interposed.