Automatic Transmission Valve Locking for Clutch Pressure Hold
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Solution Overview
Problem
Automatic transmissions experience leakage and drag losses due to relative rotation at rotary leadthroughs, necessitating continuous oil pump operation for pressure supply, even during engaged gears.
Innovation Solution
A valve device with a pressure locking mechanism using a valve housing element, valve slide element, and valve closure element, where the valve closure element is held in a second position by prestressing forces, allowing actuator pressure to be maintained without continuous oil pump operation, reducing leakage and drag losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil pump operates continuously to supply pressure to hydraulic actuators, then the actuators can maintain clutch pressure for engaged gears, but leakage and drag losses increase at rotary leadthroughs
Solution Approach 1:
The valve device is pre-configured with a valve slide element and valve closure element that can be positioned in advance to establish a pressure-locking state. When the valve slide element is in its initial position, the valve closure element is already prepared to close the fluid connection, allowing the system to lock pressure without requiring continuous pump operation.
Solution Approach 2:
The oil pump operates intermittently rather than continuously. Pressure is supplied to the hydraulic actuators only when needed for shifting operations or initial engagement, then the valve device maintains pressure through its locking mechanism. This periodic operation reduces energy consumption and minimizes leakage losses at rotary leadthroughs.
2Loss of energy
If the valve closure element is held in the closed position by prestressing forces, then pressure can be locked without continuous control pressure, but the force balance between prestressing elements must be precisely maintained
Solution Approach 1:
The valve closure element is designed to maintain its own closed position through a second prestressing element that applies a closing force. This self-servicing mechanism uses the stored elastic energy in the prestressing element to keep the valve closed and pressure locked, without requiring continuous external control pressure or complex active control systems.
Solution Approach 2:
The valve slide element acts as an intermediary between the control pressure and the valve closure element. When control pressure is applied, it moves the valve slide element, which in turn actuates the valve closure element to the closed position. This intermediary mechanism translates pressure changes into mechanical valve movement while maintaining force balance through the prestressing elements.
3Loss of energy
If the actuating section moves away from the valve closure element in the closure direction, then pressure locking can be achieved, but the valve elements must be precisely configured to interact
Solution Approach 1:
The valve device is segmented into distinct functional elements: the valve housing element with separate valve chambers, the valve slide element with actuating and pressure loading sections, and the valve closure element. This segmentation allows each component to be independently manufactured and assembled with precise tolerances, ensuring proper interaction while simplifying the overall manufacturing process.
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 valve device reduces leakage and drag losses, improves efficiency by allowing targeted pressure reduction, and enables shifting operations without extended reaction times or pressure jumps, maintaining clutch pressure without continuous control pressure.
Implementation Method 1
in the case of a prevailing actuator pressure-side fluid pressure by way of an increase in the control fluid pressure in the second valve chamber, the actuating section moves away from the valve closure element in the closure direction
Implementation Method 2
The valve slide element is loaded by means of a first prestressing element with a first prestressing force and The valve closure element is loaded by means of a second prestressing element with a second prestressing force
Data Source
AI summary
A valve device for an automatic transmission for a vehicle, preferably for a motor or utility vehicle, is provided. According to the invention, the valve device is designed such that the valve device can achieve the establishment and separation of a fluid connection between an operating pressure side and an actuator pressure side, each in a state operated without pressure. Further, an automatic transmission having such a valve device and a corresponding method for controlling such a valve device are provided.