Cam Clutch Switching Mechanism to Prevent Jamming
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Solution Overview
Problem
Existing cam clutches face issues with unwanted jamming and high force requirements for mode switching, leading to shortened service life and increased rigidity, especially when transitioning between two-way lock and freewheel modes.
Innovation Solution
A cam clutch design featuring an inner and outer race with biased cams, a frictional resistance generating means, and a mechanism for operation mode switching, which allows cams to be lifted off simultaneously in the two-way lock mode, preventing unwanted freewheeling and reducing the force needed for mode changes by using a position-restricting cage ring and irregular-shaped cam holding parts to control cam orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cams are biased to stay in contact with inner and outer races, then torque transmission is ensured, but unwanted jamming occurs when switching modes
Solution Approach 1:
The biasing means pre-biases the cams toward the disengaging direction before mode switching occurs. This preliminary action ensures that when torque is applied during mode switching, the cams are already positioned to engage smoothly without sudden jamming, as they naturally tilt toward the engaging direction under torque rather than being forced against their bias
Solution Approach 2:
The cam clutch transitions from a static biased state to a dynamic state where torque application causes the cams to tilt and engage. The system allows the cams to dynamically respond to torque conditions, switching between biased disengaged state and torque-driven engaged state, preventing jamming while maintaining reliable torque transmission
2Reliability
If all sprags are engaged with high surface contact, then lock mode is achieved, but large force is required to switch modes
Solution Approach 1:
The biasing means pre-biases the cams toward the disengaging direction before mode switching. This preliminary action reduces the engagement force by ensuring cams are not fully wedged in before switching, allowing smoother transition with lower force requirement
Solution Approach 2:
The system changes the engagement parameter by allowing partial disengagement through biasing. By controlling the degree of cam engagement through the biasing means, the system can transition between fully engaged (high torque) and partially engaged (low torque) states, reducing the force needed for mode switching
3Reliability
If cams are intentionally engaged slightly under no load, then freewheeling is prevented, but engaging torque acts as resistance force
Solution Approach 1:
The biasing means pre-biases the cams toward disengagement, creating a preliminary counter-force to the engaging torque. This preliminary action reduces the net resistance force by offsetting part of the engaging torque through the biasing force, making mode switching easier while still preventing unwanted freewheeling
4Reliability
If high rigidity components are used for changing cam orientation, then mode switching reliability is improved, but device complexity increases
Solution Approach 1:
The cam clutch uses self-service by allowing the applied torque itself to drive the cam orientation change. The torque applied to switch modes naturally tilts the cams into the correct orientation without requiring external high-rigidity actuating components, reducing device complexity while maintaining reliability
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
The design prevents unwanted jamming, reduces the force required for mode switching, and extends the service life of the cam clutch by minimizing damage to the raceways and allowing for smooth operation and high responsiveness.
Implementation Method 1
a frictional resistance generating means for generating friction resistance between a component adapted to tilt the first cams or the second cams in an engaging direction, and the inner race and/or the outer race from which the first cams and the second cams are being separated
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
To provide a cam clutch capable of preventing unwanted jamming of cams and switchable between operation modes with little force, thereby allowing size reduction. The cam clutch includes an inner race, an outer race, a plurality of cams, and a biasing means biasing the plurality of cams. The plurality of cams include first cams and second cams that have different engaging directions. The cam clutch further includes a frictional resistance generating means for generating friction resistance between a component adapted to tilt the first cams or second cams in the engaging direction, and the inner race and/or outer race when the first cams and second cams are simultaneously lifted off and separated from the raceways of the inner race and/or outer race during switching of operation modes.