Cam Clutch Selector Geometry for Low-Force Stable Switching
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Solution Overview
Problem
Existing cam clutches require a large drive force for switching between locked and free states, leading to potential incomplete switching during torque transmission, damage to raceways, and the need for precise control and larger mechanisms.
Innovation Solution
A cam clutch design featuring a cage member and selector with a cam posture control surface that includes a cam actuator and release portion, allowing for posture change without precise positioning, reducing drive force requirements and enabling simpler, more stable operation with improved responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If pin members are positioned away from the pivot point to generate large drive force for changing cam posture, then switching force is improved, but positioning precision and control precision are required
Solution Approach 1:
The cam posture control surface is segmented into two distinct functional portions: a cam actuator portion for ordinary operation and a cam release portion for releasing cam engagement. This segmentation allows each portion to be optimized independently, with the release portion positioned to effectively release cams without requiring precise positioning relative to each cam's pivot point.
Solution Approach 2:
The invention extracts the cam release function from the ordinary cam actuation function by providing a separate cam release portion on the selector. This allows the release function to be performed by a simple radial protrusion rather than requiring precisely positioned pin members, thereby eliminating the need for high positioning precision while still achieving effective cam posture change.
2Reliability
If large drive force is used to change cam posture during torque transmission, then switching reliability is improved, but raceway damage and mechanism size increase
Solution Approach 1:
The cam release portion is designed to preliminarily engage the cam surfaces before full torque transmission occurs during switching. By positioning the release portion to radially protrude toward the cams, it can initiate cam posture change in advance, reducing the peak drive force required and minimizing impact on the raceways during the switching transition.
3Ease of operation
If pin members are used to forcibly tilt cams circumferentially, then cam posture change is achieved, but precise control of rotation angle is required
Solution Approach 1:
Instead of using pin members to push the cams circumferentially from the side, the invention inverts the approach by having the selector's cam release portion radially protrude toward the cams and contact their cam surfaces directly. This radial contact method naturally guides the cam posture change without requiring precise control of the selector's rotation angle, as the cam geometry itself guides the motion.
Data Source
AI summary
To provide a simple-structured cam clutch that does not require precise control, uses a smaller drive force for forcibly changing cam postures, and provides improved clutch operation stability and high responsiveness. The cam clutch includes a plurality of cams circumferentially arranged between an inner race and an outer race and supported by a cage member, and a selector allowing a rotation angle thereof to be controlled relatively to the inner race or the outer race to which the cage member is fixed. The selector has a cam posture control surface in contact with cam surfaces of the cams and capable of causing the cams to change posture thereof. The cam posture control surface includes a cam release portion radially protruded toward the cams more than a cam actuator portion and causing the cams to change posture thereof to a non-operating posture.