Piston-Integrated Seal Asymmetry for Hydraulic Clutch Friction
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Solution Overview
Problem
Conventional piston-integrated seals in hydraulic clutches exhibit asymmetrical contact pressure distribution due to directionality, leading to increased friction during clutch disengagement, which hampers hydraulic control and shift change response.
Innovation Solution
The design features a piston-integrated seal with a main seal edge portion on the hydraulic chamber side and a sub seal edge portion on the anti-hydraulic chamber side, where the interference of the sub seal edge portion is smaller, allowing for symmetrical contact pressure distribution and reduced friction differences between engagement and disengagement strokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal lip has a directionality with asymmetrical contact pressure distribution, then the seal can maintain contact with the sliding surface, but the friction becomes greater during clutch disengagement stroke
Solution Approach 1:
The patent applies asymmetry in reverse - it intentionally creates a symmetrical seal lip structure where the contact pressure distribution is made symmetrical rather than asymmetrical. The seal lip is designed with equal angles (α1 = α2) on both sides of the maximum contact pressure point, creating symmetrical contact pressure distribution that reduces friction difference between engagement and disengagement strokes while maintaining reliable seal contact.
2Reliability
If the interference of the seal lip is increased to improve pressure resistance, then the seal performance improves, but the friction difference between engagement and disengagement strokes increases
Solution Approach 1:
The patent applies local quality by creating different interference levels at different locations of the seal lip. The maximum interference L1 is positioned at the hydraulic chamber side (main seal edge portion), while a smaller interference L2 is positioned at the anti-hydraulic chamber side (sub seal edge portion). This localized differentiation allows the seal to maintain pressure resistance where needed while reducing friction during disengagement.
3Stress or pressure
If the angle of the inclined surface closer to the hydraulic chamber side is made larger than the opposite side, then the seal contact pressure is concentrated, but the friction during disengagement stroke increases
Solution Approach 1:
The patent applies equipotentiality by making the angles of the inclined surfaces equal on both sides of the maximum contact pressure point (α1 = α2). This creates a symmetrical pressure distribution pattern where the contact pressure is evenly distributed rather than concentrated asymmetrically, reducing the friction difference between engagement and disengagement strokes while maintaining effective seal contact.
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 configuration reduces friction, enhances shift change response, and improves pressure resistance by absorbing deformation and maintaining consistent contact load, thereby improving the hydraulic clutch's operational efficiency.
Implementation Method 1
the interference L1 of the main seal edge portion 62a in the hydraulic chamber S1 side is larger than the interference L2 of the sub seal edge portion 62b... an angle α1 of an inclined surface in the hydraulic chamber S1 side... an angle β1 of an inclined surface in an opposite side... in the installed state... α1' ≅ β1'
Data Source
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AI summary
The purpose of the present invention is to improve the gear change responsiveness of a hydraulic clutch by reducing the difference in friction due to sliding direction that arises from the directionality of the seal lip (62). To achieve said purpose, the seal comprises a seal lip (62), which is integrated with the clutch piston of the hydraulic clutch and faces the hydraulic chamber (S1) side. On the section of the seal lip (62) that slides with respect to the partner sliding surface, a main seal edge (62a) is formed on the hydraulic chamber (S1) side and a secondary seal edge (62b) on the anti-hydraulic chamber (S2) side. For said main seal edge (62a) and secondary seal edge (62b), the angles (α1, α2) of the inclined surfaces on the hydraulic chamber (S1) side are smaller than the angles (β1, β2) of the inclined surfaces on the anti-hydraulic chamber (S2) side in the uninstalled state, and the angles (α1', α2') of the inclined surfaces on the hydraulic chamber (S1) side and the angles (β1', β2') of the inclined surfaces on the anti-hydraulic chamber (S2) side with respect to the partner sliding surface are roughly equal in the installed state.