Hydraulic Level Adjustment Device for Motor Vehicle Chassis
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Solution Overview
Problem
Existing motor vehicle chassis with hydraulic level adjustment systems face issues with partial or complicated lowering of the chassis from its raised position due to the design of hydraulic fluid flow back into the reservoir, leading to unsatisfactory results and increased equipment complexity.
Innovation Solution
A hydraulic level adjustment device is integrated entirely on the wheel suspension, featuring a self-sufficient shuttle valve and a throttle unit, allowing for reversible operation without external energy control, ensuring constant communication with the reservoir and optimizing fluid flow for reliable and efficient level adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulically piloted shut-off valve is used to control fluid return, then the chassis can be held in raised position, but partial lowering becomes impossible or complicated
Solution Approach 1:
The system uses the pump's own pressure output to automatically control the shut-off valve via a control line, eliminating the need for external energy sources or complex control systems. The pump's reversing mechanism self-regulates fluid flow direction, enabling both position holding and partial lowering through simple pump operation reversal.
2Adaptability or versatility
If a 3/3-way valve with blocking position is used, then fluid flow can be controlled, but the system requires external energy control and becomes more complex
Solution Approach 1:
The invention removes the blocking position functionality from the valve system, using only the connecting positions of the shuttle valve. This simplifies the valve design while maintaining full control capability through the pump's reversing action, eliminating the need for complex externally controlled valve mechanisms.
Solution Approach 2:
The shuttle valve serves multiple functions: it controls fluid flow direction, enables both raising and lowering operations, and works with the reversible pump to provide complete chassis level adjustment. The valve's simple two-position design handles all control requirements without needing additional blocking positions or external control systems.
3Ease of operation
If the shut-off valve remains open until pump direction changes, then fluid can return to reservoir, but the system requires pump operation to control lowering
Solution Approach 1:
The control line creates a feedback mechanism where the pump's output pressure automatically acts on the shut-off valve to control its opening and closing. When the pump reverses direction, the pressure feedback automatically opens the valve to allow fluid return, and when the pump pressurizes the working chamber, the feedback automatically closes the valve to hold position.
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 solution enables reliable and easy-to-handle level adjustment with minimal equipment outlay, allowing for complete hydraulic fluid return to the reservoir, facilitating both raising and lowering of the chassis without external valve control, thus improving practicability and reducing complexity.
Implementation Method 1
the working chamber (which can be pressurized to raise the base structure) via a line and valve arrangement is connected to a (first) pump connection of the pump of a hydraulic unit
Implementation Method 2
A check valve is provided between the hydraulic unit and the linear actuator in order to reliably hold the base structure of the motor vehicle in its raised position without consuming energy
Implementation Method 3
the vehicle's own weight is used to lower the floor structure to draw the hydraulic fluid out of the working space a (correspondingly designed only single-acting) linear actuator - via an open return flow line - back into the reservoir
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A hydraulic level-adjustment device (8) is assigned to at least one wheel suspension (4) in a motor vehicle chassis (1). The level-adjustment device comprises a reservoir (16), a reversible hydraulic unit (12) with a hydraulic pump (15), the pump connections (13, 14) of which are connected to the reservoir via a shuttle valve (18), and a single-acting hydraulic linear actuator (11). To lift the chassis (1), the working space (10) of the linear actuator (11) can be pressurized by the hydraulic pump (15) operated in its first pumping direction (A) via its first pump connection (13) and by a fill line (19) with a fill-check valve (20) arranged therein. To lower the chassis (1), via its second pump connection (14), the hydraulic pump (15), operated in the reverse pumping direction (B), pumps hydraulic fluid into the reservoir (16) via an outflow line (22) with a throttle unit (24) arranged therein. The pressure present upstream of the throttle unit (24) thereby acts on the control connection (26) of a lockable, drainage-check valve (27) via a control line (25) and opens same, so that, under the weight of the motor vehicle (2), hydraulic fluid is forced out of the working space (10) of the hydraulic linear actuator (11) into the reservoir (16) via the drainage line (28).