Sealing Structure for Automatic Transmission Hydraulic Pressure Maintenance
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Solution Overview
Problem
Conventional sealing structures for annular gaps between shafts and housings in automatic and continuously variable transmissions fail to maintain hydraulic pressure effectively, especially in low fluid pressure states, leading to oil leakage and reduced responsiveness during engine restarts.
Innovation Solution
A sealing structure comprising a first resin sealing ring with an endless shape and a second rubbery elastic sealing ring, where the second ring presses the first ring towards the high-pressure side and radially outer side, ensuring contact with both the sidewall and shaft hole surfaces even in low pressure conditions, preventing leakage and maintaining fluid pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing ring is configured without a tightening margin to reduce sliding torque, then the sealing ring can be closely attached to the shaft hole surface when hydraulic pressure is applied, but the sealing function is not fulfilled when hydraulic pressure is not applied
Solution Approach 1:
The sealing ring is designed with a tightening margin that allows it to dynamically adjust its position. When hydraulic pressure is applied, the sealing ring expands and closely attaches to the shaft hole surface. When hydraulic pressure is not applied, the tightening margin allows the sealing ring to maintain contact through elastic recovery, ensuring continuous sealing function while allowing necessary sliding motion.
2Reliability
If the sealing ring is configured to closely attach to the shaft hole surface when hydraulic pressure is applied, then hydraulic pressure is maintained, but oil leakage occurs and sealing function is lost when hydraulic pressure is not applied
Solution Approach 1:
The sealing ring is pre-configured with a tightening margin that enables it to maintain preliminary contact with the shaft hole surface even before hydraulic pressure is applied. This preliminary action ensures that when hydraulic pressure is not applied, the sealing ring still maintains sufficient contact to prevent oil leakage, while allowing the ring to expand and attach more closely when hydraulic pressure is applied to maintain pressure.
3Speed
If the sealing ring is configured without a tightening margin to reduce sliding torque, then the sealing ring responds quickly when hydraulic pressure is applied, but the responsiveness is reduced when the engine is restarted in a no-load state
Solution Approach 1:
The sealing ring design incorporates a tightening margin that changes the physical parameters of the sealing ring, allowing it to maintain optimal contact pressure and friction characteristics across different operating conditions. This parameter change enables the sealing ring to respond quickly when hydraulic pressure is applied while maintaining sufficient contact and lubrication during engine restart in no-load states, preventing loss of responsiveness.
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 sealing structure effectively maintains hydraulic pressure and prevents fluid leakage, ensuring reliable operation even in no-load states and during engine restarts, enhancing sealability and responsiveness.
Implementation Method 1
a second sealing ring made of a rubbery elastic body... the second sealing ring is arranged to press the first annular portion toward the high-pressure side and toward the radially outer side
Implementation Method 2
the first sealing ring is configured to slide with respect to an inner circumferential surface of a shaft hole of the housing
Data Source
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AI summary
To provide a sealing structure capable of increasing sealability and fulfilling a sealing function even in a low fluid pressure state. A first sealing ring 100 includes a first annular portion 110 that extends to a radially inner side and to a high-pressure side (H) from a radially widthwise middle, and a second annular portion 120 that extends to the radially outer side and to the high-pressure side (H) from a radially widthwise middle, a first end portion 111 of the first annular portion 110 situated at a radially inner side and the low-pressure side (L) is closely attached to a groove bottom surface of the annular groove 310, a second end portion 112 of the first annular portion 110 situated at a radially inner side and the high-pressure side (H) is closely attached to the sidewall surface of the annular groove 310 on the high-pressure side (H), and a third end portion 121 of the second annular portion 120 situated at a radially outer side and the low-pressure side (L) is configured to slide with respect to the inner circumferential surface of the shaft hole of the housing 400, and the second sealing ring 200 is arranged to press the first annular portion 110 toward the high-pressure side (H) and toward the radially outer side.