Cam Bearing Raceway Layout for Rotation Precision and Rigidity
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Solution Overview
Problem
The existing cam device structures using roller gear cam mechanisms face issues with rotation precision and rigidity due to non-uniform bearing surfaces and assembly errors, leading to degradation in roundness and increased size, which affects the performance and efficiency of the cam device.
Innovation Solution
A cam device design featuring integrated raceway surfaces on the outer periphery of the outer shaft with a radial bearing part and axial bearing parts, utilizing rolling elements and retainers, where the contact surfaces are formed directly on the output shaft and housing, preventing the degradation of roundness and enhancing rigidity without increasing the size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bolt insertion through-holes are provided in the inner ring near the output-shaft side raceway surface, then the axial bearing part can be secured to the output shaft, but the roundness of the raceway surface degrades and rotation precision deteriorates
Solution Approach 1:
The invention extracts the harmful element (bolt insertion through-holes) from the inner ring by providing the through-holes in the output shaft instead. This allows the axial bearing part to be secured while preventing the degradation of raceway surface roundness, as the through-holes are now located in a different component that does not interfere with the radial bearing's raceway surface.
2Volume of moving object
If the output shaft and bearing are integrated to decrease device size, then high precision of rotation is achieved, but the structure becomes more complex and assembly becomes difficult
Solution Approach 1:
The invention segments the bearing into distinct functional components: the inner ring with output-shaft side raceway surface, the outer ring with housing side raceway surface, and the axial bearing part as a separate assembly. This segmentation allows each component to be optimized independently while maintaining overall compactness, reducing assembly complexity compared to a fully integrated structure.
Solution Approach 2:
The invention merges the axial bearing part with the output shaft assembly through bolt connection, creating a unified rotational assembly that maintains compact size while allowing independent optimization of radial and axial bearing functions. This combining approach achieves space efficiency without the complexity of a fully integrated monolithic structure.
3Manufacturing precision
If preloading is applied to axial and radial bearings, then rotation precision is improved, but the inner ring thickness becomes non-uniform and roundness degrades
Solution Approach 1:
The invention extracts the through-holes from the inner ring and relocates them to the output shaft, allowing preloading to be applied to the axial bearing without creating non-uniform thickness in the inner ring. This maintains the uniformity of the raceway surface while still achieving the desired preloading effect for high rotation precision.
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 design improves rotation precision and maintains rigidity by preventing the degradation of roundness and reducing assembly complexities, resulting in enhanced performance and efficiency of the cam device.
Implementation Method 1
A cam device includes: one radial bearing part configured to receive a load in a radial direction of the output shaft; two axial bearing parts configured to receive opposing loads in an axial direction of the output shaft; each of the one radial bearing part and the two axial bearing parts is configured of a plurality of rolling elements and a retainer
Data Source
AI summary
A bearing rotatably supported by a housing. The bearing having one radial and two axial parts all including a plurality of rolling elements. The rolling elements of the radial bearing part contact an outer peripheral surface of an output shaft. The rolling elements of one or two of the axial bearing parts contact the outer peripheral surface of the output shaft. The rolling elements of the other axial bearing part contact a first ring-shaped part fixed to the output shaft to form an output-shaft side raceway surface. The rolling elements of the radial bearing part and of the two axial bearing parts contact the surface of a second ring-shaped part disposed on the output shaft, or the rolling elements of the radial bearing part and of one of the axial bearing parts directly contacts the inner surface of the housing to form an outer raceway surface.