Motorcycle Clutch Spring Layout to Prevent Cam Surface Interference
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Solution Overview
Problem
Existing power transmitting apparatuses for motorcycles experience abnormal noise due to interference between cam surfaces or abutment surfaces of the clutch member and pressure member caused by relatively large clearance, leading to sticking torque between driving-side and driven-side clutch discs, especially when only press-contact assisting cam means are used without back-torque limiting cam means.
Innovation Solution
Incorporating clutch springs with a resisting force greater than the sticking torque, applied through torsional rigidity or sliding resistance, and holding parts to restrict torsion, which suppresses relative rotation between the clutch member and pressure member, along with a back-torque limiting cam means to release press-contacting force when the output member's rotational speed exceeds the input member's.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a relatively large clearance is formed between the cam surfaces or abutment surfaces of the clutch member and pressure member for assembly reasons, then assembly ease is improved, but abnormal noise is caused due to interference of the abutment surfaces when relative rotation occurs
Solution Approach 1:
The clutch springs are configured to apply a resisting force to relative rotation between the clutch member and pressure member before the sticking torque can cause interference between the abutment surfaces. This preliminary counteracting force prevents the harmful relative rotation from occurring in the first place, even when clearance exists for assembly purposes.
2Device complexity
If only press-contact assisting cam means are used without back-torque limiting cam means, then device complexity is reduced, but sticking torque causes relative rotation leading to cam surface interference
Solution Approach 1:
The clutch springs perform multiple functions: they apply pressing force to transmit power between clutch discs, and simultaneously apply resisting force to prevent relative rotation between the clutch member and pressure member. This multi-functionality eliminates the need for separate back-torque limiting mechanisms while maintaining reliability.
3Reliability
If the resisting force from clutch springs is increased to suppress relative rotation, then cam surface interference is prevented, but the magnitude of the resisting force must be carefully controlled
Solution Approach 1:
The resisting force parameter of the clutch springs is specifically designed and adjusted to be greater than the maximum expected sticking torque. By optimizing this parameter, the system achieves reliable prevention of relative rotation without requiring complex control mechanisms, as the spring's inherent mechanical properties provide the necessary force.
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
Effectively suppresses interference and abnormal noise by ensuring the resisting force exceeds sticking torque, allowing for reliable transmission and cut-off of rotational power while preventing cam surface interference, even when sticking torque is present.
Implementation Method 1
the magnitude of the resisting force is set larger than a sticking torque between the driving-side clutch discs and the driven-side clutch discs, wherein the resisting force is attained by the torsional rigidity from the spring constant of the clutch spring or torsional rigidity from the wire diameter of the clutch spring
Implementation Method 2
the resisting force is attained by the torsional rigidity from the spring constant of the clutch spring or torsional rigidity from the wire diameter of the clutch spring or sliding resistance of the clutch spring
Implementation Method 3
the power apparatus further comprising holding parts for covering and holding the outer surfaces of the clutch springs and wherein the holding parts restrict torsion of the clutch springs caused by relative rotation between the clutch member and the pressure member
Implementation Method 4
a press-contact assisting cam means for increasing the press-contacting force acting on the driving-side clutch discs and the driven-side clutch discs by causing relative rotation of the pressure member and the clutch member
Implementation Method 5
a back-torque limiting cam means for releasing the press-contacting force between the driving-side clutch discs and the driven-side clutch discs due to separation of the pressure member and the clutch member caused by relative rotation of them when the rotation speed of the output member exceed that of the input member
Data Source
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AI summary
Provided is a power transmitting apparatus which is able to suppress interference between cam surfaces (4a, 5a) or abutment surfaces (α, β) of a clutch member (4) and a pressure member (5) even when a sticking torque would be caused between driving-side clutch discs (6) and driven-side clutch discs (7). The power transmitting apparatus for transmitting a rotational power inputted to an input member (1) to an output member (3) or cutting-off the rotational power by press-contacting a plurality of driving-side clutch discs (6) and a plurality of driven-side clutch discs (7) each other or releasing them comprising a clutch housing (2) mounted thereon the driving-side clutch discs (6); a clutch member (4) connected to the output member (3); and a pressure member (5) for press-contacting the driving-side clutch discs (6) and the driven-side clutch discs (7) each other or releasing the press-contacting force therebetween characterized in that application of a resisting force for resisting relative rotation between the clutch member (4) and the pressure member (5) can be attained and the magnitude of the resisting force is set larger than a sticking torque between the driving-side clutch discs (6) and the driven-side clutch discs (7).