Compact Pilot Stage for High-Pressure Hydraulic Valves
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Solution Overview
Problem
Existing high-pressure hydraulic valves require significant space and are costly due to the need for external proportional magnets and throttle valves, which limits their application in compact systems like agricultural machinery, and they suffer from precision issues and high manufacturing tolerances.
Innovation Solution
A compact pilot stage design where the guide piston acts as an armature with a coil attached externally, eliminating the need for external magnets and throttle valves, using high-pressure seals to maintain a pressureless piston chamber, and incorporating a displacement sensor for precise control, reducing manufacturing tolerances and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external proportional magnets and throttle valves are used to control high-pressure hydraulic valves, then precise proportional control can be achieved, but the device occupies significant space and has high manufacturing costs
Solution Approach 1:
The patent merges the proportional magnet and throttle valve functions into the pilot stage assembly itself. The coil is mounted directly on the pilot stage housing, and the pilot stage integrates both electromagnetic actuation and pressure reduction functions, eliminating the need for separate external components and reducing overall device space.
Solution Approach 2:
The pilot stage is designed as a multi-functional component that simultaneously serves as the housing for the coil, the pressure-reducing element, and the control mechanism. This universal design consolidates multiple functions into a single component, reducing the number of separate parts needed and minimizing space occupation.
2Measurement precision
If external proportional magnets and throttle valves are used for high-pressure hydraulic valve control, then proportional control is achieved, but manufacturing costs increase
Solution Approach 1:
By combining the proportional magnet and throttle valve into the pilot stage assembly, the patent reduces the total number of components that need to be manufactured, assembled, and calibrated. This integration simplifies the manufacturing process and reduces assembly costs while maintaining control precision.
Solution Approach 2:
The multi-functional pilot stage design reduces the bill of materials and manufacturing complexity. By making the pilot stage serve multiple functions, the patent eliminates the need to manufacture and source separate external magnets and throttle valves, thereby reducing overall manufacturing costs.
3Volume of stationary object
If a pressureless piston chamber is used with high-pressure seals, then the pole tube can be designed with thin walls saving space and cost, but the seal requirements become more critical
Solution Approach 1:
The patent extracts the high-pressure hydraulic fluid from the piston chamber by providing a hydraulic connection that supplies pressure to a compensation chamber rather than directly to the piston chamber. This separation allows the piston chamber to be pressureless while maintaining reliable sealing through the high-pressure seal at the compensation chamber.
Solution Approach 2:
The high-pressure seal acts as an intermediary element that isolates the pressureless piston chamber from the high-pressure hydraulic system. By placing the seal at the compensation chamber rather than in the piston chamber, the patent enables thin-walled construction while maintaining seal reliability through proper placement and design of the sealing element.
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 significantly reduces space and manufacturing costs, enhances precision, and improves response behavior by minimizing dead zone and hysteresis, allowing for precise control of high-pressure hydraulic valves with reduced component count and weight.
Implementation Method 1
The guide piston (104, 4) is moved in the axial direction within the piston chamber (110) of the housing (102) by generating a magnetic field with a coil (119) attached to an outer side of the housing (102), the guide piston (104, 4) also acting as an armature of the magnet
Implementation Method 2
a compensation chamber (107, 7) connected to the hydraulic valve (108, 8) compensates for forces acting on the follower piston (106, 6) of the hydraulic valve (108, 8)
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The subject matter of the invention is a pilot-control stage of a proportionally controlled high-pressure hydraulic valve, having a housing (102), in which a piston chamber (110) is formed, having a guide piston which is held such that it can be displaced axially in the housing (102), wherein the guide piston comprises a control piston (104), which is held such that it can be displaced axially in the piston chamber (111), and a tappet (105) which reaches through the housing (102), with the result that the tappet (105) can be operatively connected to a following piston (106) of the hydraulic valve (108) and to a compensating piston (115) which reaches into a compensating chamber (107) which is formed in the control piston (104), wherein an axially oriented tappet bore (112) is formed in the guide piston, which tappet bore (112) reaches from the compensating chamber (107) as far as the free end of the tappet (105), with the result that the compensating chamber (107) is connected hydraulically to the hydraulic valve (108). The provision of a pilot-control stage which takes up much less space with the same performance and which can be produced less expensively is achieved by virtue of the fact that the housing (102) is formed as a pole tube at least in the region of the control piston (104), that an electromagnetic coil (119) is arranged around the pole tube, that the control piston (104) is configured as an electromagnetic armature, with the result that the coil (119) interacts with the control piston (104) in such a way that, when the coil (119) is loaded with electricity, the control piston (104) and therefore also the tappet (105) are moved axially, and that the piston chamber (110) is sealed with respect to the high-pressure region of the hydraulic valve (108) via a high-pressure seal between the compensating piston (107) and the control piston (104) and via a high-pressure seal between the tappet (105) and the housing (102), in such a way that the piston chamber (110) is kept in the low-pressure range or pressureless.