Cam Clutch Contact Surface Layout to Prevent Cam Jamming
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cam clutches experience jamming issues during mode switching due to simultaneous engagement of cams, requiring high forces and potentially damaging engagement surfaces, and lack a mechanism to prevent two-way lock modes.
Innovation Solution
A cam clutch design with independently movable contact surface members and movement restricting portions allows smooth mode switching by preventing simultaneous engagement of cams through backlash movement, using a biasing member to facilitate this movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the retainer is controlled to forcibly tilt each of the first sprag and the second sprag to change operation modes, then the clutch can be switched between driving and idling modes, but a two-way lock mode that prohibits relative two-way rotation cannot be implemented and the structure becomes complex
Solution Approach 1:
The clutch is divided into two independent one-way clutch mechanisms: a first one-way clutch mechanism with a first sprag for controlling forward rotation, and a second one-way clutch mechanism with a second sprag for controlling reverse rotation. Each mechanism can be independently engaged or disengaged, enabling four operation modes (two-way free, forward lock, reverse lock, two-way lock) without complex retainer control. This segmentation allows simple binary control of each direction independently.
2Power
If the first sprag and the second sprag are biased so as to come into contact with the outer race and the inner race, then torque transmission is enabled, but cam jamming may occur when torque is removed and sprags tilt in opposite directions simultaneously
Solution Approach 1:
The contact surface members are designed to be movable rather than fixed, allowing them to dynamically adjust their positions in response to torque changes. When torque is applied, the contact surface members move to maintain proper cam engagement. When torque is removed, they can move independently to prevent simultaneous engagement of both sprags, thus preventing cam jamming while maintaining reliable torque transmission during operation.
3Strength
If all the sprags are engaged with each other in a state of high surface pressures, then lock mode is achieved, but a large force is required to switch to free mode which may damage engagement surfaces and reduce service life
Solution Approach 1:
Movable contact surface members are introduced as intermediary elements between the fixed raceways and the cams. These contact surface members absorb the high contact pressures during locking operation and can move to reduce engagement forces during mode switching. This intermediary mechanism protects the critical engagement surfaces of the fixed raceways and cams from damage, extending service life while maintaining strong locking capability.
4Ease of operation
If a high rigidity is required of an attitude changing member for changing the attitudes of the sprags, then mode switching can be achieved, but the device size increases and complexity increases
Solution Approach 1:
The attitude changing mechanism utilizes the natural movement and compliance of the contact surface members rather than requiring a high-rigidity actuating mechanism. The contact surface members can move independently to facilitate sprag attitude changes, eliminating the need for large, rigid mode switching mechanisms. This dynamic approach reduces device size and complexity while maintaining ease of operation.
Data Source
AI summary
Provided is a cam clutch that prevents occurrence of cam jamming. The cam clutch includes a first contact surface member (130) and a second contact surface member (140) that have cam contact surfaces respectively which come into contact with a first cam (170a) and a second cam (170b) that are engaged with an outer race (110) and an inner race (160) in mutually different directions. The first contact surface member (130) and the second contact surface member (140) are provided at different positions in a rotation axis direction and configured to be independently movable in a circumferential direction relative to an outer race main body (120). The outer race main body (120) has a first movement restricting portion (122) and a second movement restricting portion (123) that restrict the movement of the first contact surface member (130) and the second contact surface member (140) in respective locking directions.