Hydraulic Steering Selector Valve Wear Reduction
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Solution Overview
Problem
The existing hydraulic steering devices face issues with wear and manufacturing complexity due to the requirement for a short cardan shaft and the need for special components to prevent fluid leakage, which complicates the construction and accuracy of parts fitting.
Innovation Solution
The selector valve is arranged between the two fluid meters with a shaft extending through the valve element, allowing for a longer shaft and the use of standard components, reducing wear and simplifying the manufacturing process by using a sliding valve element and removable holding means for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a short cardan shaft is used between the two fluid meters, then the hydraulic steering device can be compact, but the manufacturing complexity increases and wear occurs due to limited movement opportunities
Solution Approach 1:
The cardan shaft is divided into two separate shafts instead of using a single short cardan shaft. This segmentation allows each shaft to be longer and more manageable, reducing wear and simplifying manufacturing while maintaining the compact overall structure through proper spatial arrangement of the fluid meters and selector valve
Solution Approach 2:
The selector valve is positioned as an intermediary component between the two fluid meters, with the shafts extending through it. This intermediary arrangement allows the shafts to be longer and reduces the complexity of fitting components together, as the selector valve provides a mounting point that simplifies the overall assembly
2Ease of operation
If a rotating valve element is used in the selector valve means, then the valve can be actuated, but the construction becomes complicated and requires high clamp forces that prevent rotation
Solution Approach 1:
Instead of using a rotating valve element that rotates about its own axis, the invention uses a sliding valve element that moves parallel to the shaft axis. This inversion of the valve mechanism simplifies the construction by eliminating the need for complex rotating seals and bearing arrangements, while still providing effective valve actuation between different positions
3Stability of the object's composition
If high clamp forces are applied to secure the selector valve means, then the assembly is stable, but the rotating valve means can no longer be rotated
Solution Approach 1:
The valve element uses a sliding mechanism parallel to the shaft axis instead of rotation about the axis. This allows the valve to be securely clamped at any position along the sliding path while maintaining operational capability, as the sliding motion does not require the same clearance and flexibility as rotational motion
4Ease of manufacture
If standard components are used instead of special components, then the manufacturing process is simplified, but the accuracy for fitting parts together must be maintained
Solution Approach 1:
The hydraulic steering device is segmented into modular components (fluid meters, selector valve, shafts) that can be manufactured separately using standard components and then assembled. This segmentation allows each component to be produced with standard tolerances and then precisely positioned during assembly, reducing the need for ultra-precise manufacturing of individual parts while maintaining overall assembly accuracy
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 reduces wear and simplifies the manufacturing process by allowing the use of standard components, maintaining the overall length of the steering device and ensuring fluid tightness, while enabling easy testing and adjustment of the selector valve before integration.
Implementation Method 1
said selector valve means having a valve element shiftable in a direction parallel to said axis
Implementation Method 2
Automatic switching between the two modes can be realized by means of the pressure at the supply port and by means of a spring acting in the opposite direction
Implementation Method 3
When a vehicle equipped with such a hydraulic steering device is driven in a so called 'normal mode' the two fluid meters are arranged in parallel
Data Source
AI summary
A hydraulic steering device is provided comprising a supply port arrangement having a supply port (P) and a return port (T), a working port arrangement having two working ports (L, R), direction valve means (2) arranged between said supply port arrangement and said working port arrangement, at least two fluid meters (3, 4), each of said fluid meters (3, 4) having a movable metering element (12, 15), said metering elements (12, 15) being connected by a shaft (5), said shaft (5) having an axis, selector valve means (6) being provided, said selector valve means (6) in a first position arranging said fluid meters (3, 4) hydraulically in parallel and in a second position shutting off one of said fluid meters (3, 4), said selector valve means (6) having a valve element (20) shiftable in an direction parallel to said axis. It is an object to reduce wear in said hydraulic steering device in a simple manner. To this end said selector valve means (6) are arranged between said two fluid meters (3, 4), said shaft (5) extending through said valve element (20).