Variable Width Cam Groove Eliminates Roller Follower Backlash
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Solution Overview
Problem
The existing roller type turntables in machine tools experience backlash between the cam component and roller followers, leading to shock, vibration, reduced positioning accuracy, and machining accuracy due to the gap between the cam groove and roller followers.
Innovation Solution
The design of a cam component with a first side rib wall and a second side rib wall featuring continuous cam curved surfaces forming a cam groove with a variable width, allowing symmetric compression of roller followers to eliminate backlash and reduce noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cam groove width is made slightly larger than the roller follower outer diameter to allow rotation, then the roller follower can rotate freely in the cam groove, but a gap is formed between the rib wall and roller follower causing backlash
Solution Approach 1:
The cam groove width is designed to be variable rather than constant. The groove width changes dynamically along the groove length, being larger than the roller follower outer diameter at the entrance to facilitate rotation, and gradually decreasing to match the roller follower outer diameter at the compression zone to eliminate backlash. This dynamic geometry allows the system to transition from a state permitting rotation to a state ensuring precision.
Solution Approach 2:
Different sections of the cam groove have different width characteristics tailored to their specific functions. The entrance section has a larger width to allow easy insertion and rotation of the roller follower, while the compression zone has a width matching the roller follower outer diameter to eliminate gaps and ensure precise positioning. This local differentiation of groove quality resolves the contradiction between rotation ease and positioning accuracy.
2Device complexity
If the roller follower contacts only one side rib wall of the cam groove, then the structure is simple, but backlash is formed between the roller follower and the other side rib wall
Solution Approach 1:
The cam groove is designed with a variable width profile that transitions from a wider entrance section to a narrower compression zone. This dynamic geometry enables the roller follower to be compressed symmetrically between both rib walls in the compression zone, eliminating backlash while maintaining a relatively simple overall structure. The variable width design is more effective than adding complex adjustment mechanisms.
Solution Approach 2:
The cam groove exhibits asymmetric characteristics in its width distribution along its length. The groove width is intentionally made asymmetric relative to the roller follower position, being larger at the entrance and smaller at the compression zone. This asymmetric width profile allows the roller follower to be engaged and compressed effectively, eliminating backlash without requiring symmetric complex structures.
3Ease of manufacture
If the cam groove has equal width throughout, then the manufacturing is simpler, but a gap is formed between the rib wall and roller follower causing shock and vibration
Solution Approach 1:
The cam groove width is designed as a dynamic parameter that varies continuously along the groove length rather than remaining constant. The width transitions from larger at the entrance to match the roller follower outer diameter at the compression zone. This dynamic geometry ensures continuous contact between the roller follower and both rib walls during compression, eliminating gaps that cause shock and vibration while maintaining manufacturability through standard machining processes.
Solution Approach 2:
The key parameter of cam groove width is changed from a constant value to a variable value that changes along the groove length. This parameter change allows the groove to provide both easy entry/rotation for the roller follower and precise compression without gaps. The variable width parameter effectively eliminates shock and vibration caused by gaps while remaining manufacturable.
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 solution effectively eliminates backlash, enhances positioning accuracy, and improves machining accuracy by ensuring precise alignment and smooth operation of the turntable without shock or vibration during start, stop, or rotation.
Implementation Method 1
the first side rib wall and the second side rib wall can compress on at least one pair of the roller followers of the turntable symmetrically in the first and second directions
Data Source
AI summary
The present invention provides an indexing device for a turntable which is provided with a plurality of roller followers arranged at equal angular intervals; a cam component is provided on one side of the turntable. The cam component is provided with a first side rib wall with a continuous cam curved surface in a first direction and a second side rib wall with a continuous cam curved surface in a second direction, and the first side rib wall and the second side rib wall face opposite sides to form a cam groove with a variable groove width for guiding the movements of the roller followers and rotating the turntable; wherein the first side rib wall and the second side rib wall can compress on at least one pair of the roller followers of the turntable symmetrically in the first and second directions, so as to effectively eliminate the backlash problem between the cam component and the roller followers and improve the positioning accuracy of the turntable.