Slide Valve Spool Segmentation for Zero-Energy Position Holding
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Solution Overview
Problem
Existing slide valves in automatic transmissions require energy to maintain the position of double-acting hydraulic cylinders, leading to unwanted hydraulic pressure buildup and energy consumption, especially when the cylinder is not in use.
Innovation Solution
A spool valve design with two working ports that disconnect from the hydraulic inlet and connect to the outlet when no energy is supplied, allowing for 'zero switch-off' and preventing pressure buildup, featuring a valve slide with control sections that hydraulically connect and disconnect ports based on axial position, eliminating the need for axial and radial bores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional spool valve with axial and radial bores is used to control a double-acting hydraulic cylinder, then the valve can switch hydraulic flow, but energy is continuously consumed to maintain piston position and prevent hydraulic pressure buildup
Solution Approach 1:
The first control section is divided into a first partial control section and a second partial control section with a recess between them. This segmentation allows the valve spool to create separate control paths: one for pressurizing the first chamber and another for venting the second chamber, enabling position maintenance without continuous energy consumption.
Solution Approach 2:
The recess in the valve spool acts as an intermediary element that enables hydraulic connection between the first working port and outlet ports. This recess provides a controlled pathway for hydraulic fluid to equalize pressure between chambers without requiring continuous actuator energy, thereby maintaining position stability.
2Ease of manufacture
If a conventional spool valve design with axial and radial bores is used, then hydraulic flow can be switched, but the valve requires complex internal bore structures that increase manufacturing complexity
Solution Approach 1:
The invention eliminates the complex axial and radial bore structures from the valve spool by extracting their functionality. Instead of using internal bores, the control sections and recesses on the valve spool surface perform the same hydraulic routing function, significantly simplifying manufacturing while maintaining valve functionality.
Solution Approach 2:
Instead of creating complex internal bore pathways within the valve spool, the invention inverts the approach by using surface-level control sections and recesses that hydraulically connect ports through the valve body. This externalized control path eliminates the need for complex internal drilling and boring operations.
3Power
If the valve spool is actuated to connect working ports to the hydraulic inlet, then hydraulic pressure builds up for actuation, but pressure buildup is impeded when energy is not supplied to the actuator
Solution Approach 1:
The valve system dynamically adapts its hydraulic connections based on actuator state. When the actuator is energized, the valve spool shifts to connect working ports to the hydraulic inlet for rapid pressure buildup and actuation. When the actuator is not energized, the recess automatically connects working ports to outlet ports for rapid pressure equalization, eliminating response delays.
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 saves energy by maintaining the piston position without actuator energy, reducing costs and preventing hydraulic pressure buildup due to leakage, allowing for efficient control of double-acting hydraulic cylinders in automatic transmissions.
Implementation Method 1
the first and second working ports (A, B) can be hydraulically connected to the hydraulic inlet (P) and/or to the first and second outlet connections (T1, T2), depending on an axial position of the valve spool (20)
Implementation Method 2
The actuator (48) can be, for example, an electromagnet
Implementation Method 3
an axially acting valve spring (44), which is, for example, designed as a helical spring
Data Source
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AI summary
A slide valve is described, having a valve slide, which is able to be impinged upon by an actuator in a first direction and by an impinging device in a second direction, opposite to the first direction, and which, using control sections is able to connect hydraulically a first working connection to an inlet connection or an outlet connection, and a second working connection to an or the inlet connection or an or the outlet connection, a first control section assigned to the first working connection including at least a first and a second subcontrol section and a recess that is situated axially between them and is preferably radially encircling, which is able to connect hydraulically the working connection to an or the outlet connection as a function of an axial position of the valve slide.