Split Dynamic Seal for Hydrostatic Actuator Low-Temperature Reliability
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Solution Overview
Problem
Existing hydrostatic actuators for motor vehicles face challenges in maintaining a reliable seal at low temperatures due to the dependence on external energy sources for heating elements, which increases complexity and reduces thermal efficiency and reliability.
Innovation Solution
The design incorporates two dynamically sealing lips with distinct orientations and geometries, forming multiple surfaces that adapt to pressure differences, ensuring a self-reinforcing seal without external energy, even at low temperatures, by maintaining a lower pressure in the intermediate space between the lips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heating element is added to maintain seal temperature, then sealing reliability at low temperatures is improved, but device complexity and energy consumption increase
Solution Approach 1:
The sealing system uses the hydraulic pressure differential itself to activate the sealing mechanism. When pressure differential exceeds the spring preload, the flexible membrane deforms to press the sealing lips against the sealing surfaces, creating a self-activating seal that requires no external energy input or control systems.
Solution Approach 2:
The heating element and its associated control circuitry are completely removed from the system. The patent achieves low-temperature sealing reliability through mechanical means alone, extracting the thermal management subsystem that caused complexity and energy consumption issues.
2Reliability
If a heating element is added to maintain seal temperature, then sealing reliability at low temperatures is improved, but energy consumption increases
Solution Approach 1:
The sealing mechanism is activated by the system's own operational pressure differential. The hydraulic fluid pressure itself provides the actuating force needed to deform the flexible membrane and engage the sealing lips, eliminating the need for external energy sources like heating elements.
Solution Approach 2:
The pressure differential that could potentially cause leakage is converted into the activating force for the seal. By designing the sealing mechanism to respond to pressure differential, the system turns a potential harmful effect into the beneficial driving force for seal engagement.
3Ease of manufacture
If sealing lip geometry is standardized, then manufacturing simplicity is maintained, but adaptability to different pressure conditions and installation spaces is reduced
Solution Approach 1:
The sealing lip is divided into multiple independent sections with different geometries. Each section can be optimized for specific pressure conditions or installation requirements, allowing the seal to adapt to various operating conditions while maintaining a relatively simple overall structure that is easy to manufacture.
Solution Approach 2:
Different portions of the sealing lip have different geometries and properties tailored to their specific functions. This allows the seal to handle varying pressure conditions effectively while maintaining manufacturing simplicity through the use of a single integrated component design.
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 guarantees a consistent, high-seal quality and robustness against temperature variations, enhancing operational reliability and reducing the risk of leakage, while eliminating the need for external energy sources.
Implementation Method 1
the first sealing lip and the second sealing lip are matched to the piston in such a way that the pressure in the intermediate space is lower than on the outside of the intermediate space
Implementation Method 2
the elasticity, which enables the dynamic sealing lip in particular to be pressed on, decreases as the temperature falls
Data Source
Figure 1~2
AI summary
The invention relates to a hydrostatic actuator (1) for a motor vehicle assembly, comprising a piston (2) which is arranged within a housing (3) in a longitudinally movable manner. A seal (5) is inserted between the lateral surface (4) of the piston (2) and the housing (3) in a fluid-tight manner, and the seal (5) has a securing region (6), which rests against the housing (3) or the piston (2) in a statically sealing manner, and a seal lip region (7), which rests against the piston (2) or the housing (3) that can be moved relative to the securing region (6) in a dynamically sealing manner. The seal lip region (7) has two seal lips (8, 9), one of which is provided for contacting the surface of the piston (2) or the housing (3) that can be moved relative to the securing region (6) in the event of positive pressure and the other of which contacts same in the event of negative pressure for dynamic sealing purposes.