Common Stop Valve for Automatic Transmission Hydraulic Control
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Solution Overview
Problem
Existing hydraulic control systems in automatic transmissions require multiple stop valves for each shift element, leading to increased complexity, potential for errors, and reduced functional reliability, as well as higher assembly costs and energy consumption due to the need for multiple pressure sources.
Innovation Solution
A hydraulic control device with a common shiftable stop valve connects multiple shift elements to a single pressure adjusting device, allowing all actuating pressure chambers to be simultaneously sealed or opened, reducing the risk of errors and energy consumption by eliminating the need for individual valves and pressure sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple individual stop valves are used for each shift element, then each actuating pressure chamber can be sealed independently, but the device complexity increases and functional reliability decreases
Solution Approach 1:
The patent combines multiple individual stop valves into a single common stop valve that can seal all actuating pressure chambers simultaneously. This merging reduces the number of components from multiple valves to one valve, thereby reducing device complexity while maintaining the ability to seal all chambers, which improves functional reliability by eliminating potential failure points associated with multiple valves.
Solution Approach 2:
The common stop valve is designed to perform multiple functions: it can seal all actuating pressure chambers simultaneously and can be actuated by a single control signal. This multi-functional design eliminates the need for multiple specialized valves, reducing complexity while ensuring reliable operation across all shift elements.
2Reliability
If multiple stop valves are used for each shift element, then pressure can be maintained in each chamber, but the number of parts increases leading to higher assembly costs and installation space
Solution Approach 1:
The patent merges multiple stop valves into a single common stop valve that maintains pressure in all actuating pressure chambers through a unified sealing mechanism. This reduces the number of parts significantly, lowering assembly costs and reducing installation space while maintaining the pressure maintenance function across all chambers.
3Force
If the transmission pump maintains high pressure throughout the operating period, then sufficient compression force is available for torque transfer, but power consumption increases and transmission efficiency decreases
Solution Approach 1:
The patent implements periodic action by using the common stop valve to maintain high pressure in actuating pressure chambers only when needed for torque transfer during shifting operations. When shifting is not required, the stop valve allows pressure to be released, and the pump operates at lower pressure for cooling and lubrication. This periodic maintenance of high pressure reduces overall power consumption while ensuring sufficient compression force is available when required.
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 solution enhances the functional reliability and efficiency of automatic transmissions by reducing the number of components, minimizing energy consumption, and maintaining actuating pressure independently of the pressure source, thereby reducing engine power diversion to the hydraulic system.
Implementation Method 1
the actuating pressure enclosed in the actuating pressure chamber essentially retains its value regardless of the pressure of the pressure source
Implementation Method 2
clutches, which connect two rotatable elements to each other in a torque-proof manner, and brakes, which connect in a torque-proof manner a rotatable element with a fixed element
Implementation Method 3
the transmission stages are adjusted by frictional-locking shift elements, which are to be understood in the following as frictional-locking clutches or brakes
Data Source
AI summary
A hydraulic control device for controlling multiple torque-transferring shift elements of an automatic transmission, where each of the shift elements features at least one hydraulic actuator, which includes one actuating pressure chamber, at least one stop valve and at least one hydraulic shift device with multiple pressure adjusting devices connected to the different shift elements. Thereby, the stop valve is configured and arranged in such a manner that the actuators of at least two shift elements are hydraulically connectable to the pressure adjusting devices through a common stop valve. In a first shifting position, all actuating pressure chambers of the at least two shift elements are tightly sealed by the stop valve. In a second shifting position, all actuating pressure chambers of the at least two shift elements are connected through the stop valve to the pressure adjusting device allocated to the respective shift element.