Stepped-Thickness Sealing Lip Structure for Compact Transmission Pistons
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Solution Overview
Problem
Conventional sealing devices in automatic transmissions face challenges in downsizing while maintaining strength, as reducing the thickness of components leads to degradation in sealing device strength.
Innovation Solution
The sealing device features an annular design with varying thickness portions along its edge, allowing for a sealing lip to cover thickness steps, thereby maintaining strength while reducing dimensions, and includes an annular piston and cancel plate with specific thickness gradients to accommodate these steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the piston or cancel plate is reduced to achieve downsizing, then the size of the automatic transmission is reduced, but the strength of the piston or cancel plate is reduced
Solution Approach 1:
The piston or cancel plate is designed with non-uniform thickness distribution, featuring a first portion with greater thickness for strength and a second portion with reduced thickness for downsizing. This local quality variation allows the structure to maintain necessary strength in critical areas while reducing overall size and weight of the sealing device.
Solution Approach 2:
The edge portion of the piston or cancel plate is segmented into multiple portions (first portion and second portion) with different thicknesses. This segmentation enables different functional zones within the same component, allowing the thicker first portion to provide structural strength while the thinner second portion contributes to compactness.
2Volume of moving object
If the thickness of the piston or cancel plate is reduced, then space is saved, but the strength of the sealing device is degraded
Solution Approach 1:
The sealing device incorporates local quality variation through non-uniform thickness distribution in the piston or cancel plate. The first portion maintains sufficient thickness to ensure structural reliability and strength, while the second portion is thinned to reduce overall device volume, achieving both space savings and maintained reliability.
Solution Approach 2:
The sealing device uses a composite structure combining portions with different thicknesses in the same component. This composite approach allows the thicker first portion to provide mechanical strength and reliability while the thinner second portion reduces mass and volume, creating an optimized composite structure for both performance and compactness.
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 design achieves space savings in sealing devices without degrading their strength, enhancing durability and adhesion between sealing lips and components, while maintaining pressure resistance.
Implementation Method 1
The sealing lip is slidable while in close contact with the cylinder
Implementation Method 2
A return spring attached to the balance oil chamber between the piston seal and the canceller seal effects a return operation of the piston seal
Implementation Method 3
an annular first sealing lip portion that is adhered to at least a part of a first edge portion along an inner periphery of the first body portion
Data Source
AI summary
An annular sealing device in a recess in a housing has a movable annular piston; and an annular inner periphery sealing lip adhered to part of a first edge along an inner periphery of the piston and that slides while in contact with the recess. The first edge has a first inner periphery edge with a first thickness; a second inner periphery edge adjoining the first inner periphery edge and with a thinner second thickness; and a third inner periphery edge adjoining the second inner periphery edge and with a thinner yet third thickness. The first, second, and third inner periphery edges are in this order from the outer periphery of the piston. The inner periphery sealing lip is adhered to the third inner periphery edge and part of the second inner periphery edge to cover a step formed by thickness differences between the second and third inner periphery edges.