Hydraulic Valve Stepped Piston Proportional Control
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Solution Overview
Problem
Existing hydraulic valves for dual clutch transmissions face challenges in operating multiple working connections effectively, cost-effectively, and in a space-saving manner with good control behavior, particularly in requiring precise control of hydraulic fluid pressure and flow.
Innovation Solution
A hydraulic valve design featuring a valve housing with a stepped bore and a piston supported by a spring and a solenoid actuator, allowing for proportional control of hydraulic fluid pressure through a balance of magnetic, spring, and hydraulic forces, enabling independent pressure control of two working ports with a single solenoid actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a stepped piston with reduced outer diameter is used to control multiple working connections, then the ability to block and connect hydraulic connections is improved, but the device complexity increases due to the need for precision-machined stepped bores and bushings
Solution Approach 1:
The piston is divided into multiple cylindrical sections with different diameters (first cylindrical section with larger diameter, second cylindrical section with smaller diameter). Each section can independently interact with control grooves in the valve housing, enabling separate control of multiple working connections. This segmentation allows the single piston to perform multiple control functions that would otherwise require multiple valves or complex mechanisms.
Solution Approach 2:
The single piston with stepped design serves multiple functions: it can block different hydraulic connections, connect different working ports to tank or pressure, and provide proportional control for multiple working connections simultaneously. The first and second cylindrical sections each interact with different control grooves, making the piston a universal control element for the entire hydraulic valve assembly.
2Manufacturing precision
If precision-machined stepped bores with bushings are used to guide the stepped piston, then the control precision is improved, but the manufacturing cost and complexity increase
Solution Approach 1:
Instead of machining the entire bore with high precision, only specific sections require precision machining. The valve housing bore is machined with fine tolerance only in the regions where control grooves are formed and where the piston sections interact. Other portions of the bore can have coarser tolerances, reducing overall manufacturing complexity while maintaining control precision where needed.
Solution Approach 2:
Rather than creating a complex stepped bore structure in the valve housing to guide the piston, the invention inverts the approach by making the piston itself the precision element with stepped diameters. The piston's stepped sections provide the necessary geometric precision for control, while the valve housing bore can be simpler. This reverses which component carries the precision machining requirements.
3Adaptability or versatility
If radial recesses are formed in the bushing wall to connect control grooves, then the hydraulic connectivity is improved, but the manufacturing complexity of the bushing increases
Solution Approach 1:
The control grooves are formed directly in the valve housing rather than requiring separate bushing components with radial recesses. By integrating the control groove functionality into the valve housing structure itself, the invention eliminates the need for additional bushing features. The piston's stepped sections interact directly with these integrated control grooves, providing hydraulic connectivity without increasing bushing complexity.
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 enables efficient, reliable, and compact operation of hydraulic valves with independent pressure control of two working ports, achieving proportional pressure regulation and improved control behavior by leveraging the interaction of magnetic, spring, and hydraulic forces.
Implementation Method 1
with a solenoid actuator which is used for applying a magnetic force is provided, is coupled to be longitudinally displaceable
Implementation Method 2
which is supported at one end on the valve housing by means of a spring which applies a spring force
Implementation Method 3
A force on the piston is proportional to the difference between the two effective areas in the first section of the piston. In order to implement a controlled operation of the hydraulic valve, it is necessary to provide a corresponding counterforce, which can be implemented by applying pressure to the difference between the effective areas.
Data Source
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AI summary
The invention relates to a hydraulic valve (10) with at least two switching positions (S1, S2, S3), comprising a valve housing (12) with a bore (14) having sections (24, 26) of different diameters along its longitudinal direction (L). The hydraulic valve further comprises a supply port (P) for supplying a hydraulic fluid, at least one first working port (B) and one second working port (A), at least one first reservoir outlet (T1) and one second reservoir outlet (T2) for discharging the hydraulic fluid, and a piston (16) arranged in the bore (14) in its longitudinal direction (L), which is supported at one end (38) on the valve housing (12) by means of a spring (40) that applies a spring force and is longitudinally displaceably coupled to a magnetic actuator (36) that is provided for applying a magnetic force.A first control groove (18) selectively connects the first working port (B) to either the first tank outlet (T1) or the supply port (P), while a second control groove (20) selectively connects the second working port (A) to either the second tank outlet (T2) or the supply port (P). The hydraulic valve further comprises a pin (22) arranged longitudinally (L) relative to the piston (16) so as to be longitudinally displaceable. This pin interacts with the spring (40) in at least one switching position (S1, S2, S3) and is hydraulically connected to the second control groove (20). The first control groove (18) is bounded by first working surfaces (28, 30) of different sizes. The larger of the first working surfaces (28) is arranged in a first section (24) with a larger diameter, and the smaller of the first working surfaces (30) is arranged in a second section (26) with a smaller diameter than in the first section (24).The second control groove (20) is bounded by second effective surfaces (42, 43) which are arranged in the section (26) of the bore (14) with a smaller diameter.