Liquid Pressure Motor Back Pressure Stabilization
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Solution Overview
Problem
The hydraulic braking device experiences pressure oscillation and loud braking noise due to high pressures in the back pressure chamber when the hydraulic motor is stopped, leading to variable braking force and significant vibrations.
Innovation Solution
A liquid pressure motor with a counter balance valve, bypass passage, connection valve, and pilot passage arrangement that connects the back pressure chamber to a tank when the fluid pressure drops, maintaining a constant valve opening pressure and reducing vibrations by stabilizing the operation of the connection valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control valve returns to neutral position during braking, then the braking force is generated, but the pressure in the back pressure chamber remains high causing pressure oscillation and loud braking noise
Solution Approach 1:
The invention divides the control system into two independent pressure control paths: the main control passage (47) for normal operation and a separate bypass passage (53) with connection valve (2) for braking operation. This segmentation allows the back pressure chamber (21) to be independently controlled during braking, preventing pressure oscillation while maintaining stable braking force.
Solution Approach 2:
The connection valve (2) acts as an intermediary element that directly controls the back pressure chamber (21) during braking operations. By introducing this intermediate control mechanism, the system can maintain constant valve opening pressure and eliminate pressure oscillation without affecting the main control system.
2Force
If the on-off valve operates with pressure higher than setting pressure, then braking force is generated, but vibrations are significant and braking noise is loud
Solution Approach 1:
The invention changes the pressure parameter in the back pressure chamber by providing a direct control path from the inlet/outlet passages to the back pressure chamber through the connection valve. This allows the back pressure to be dynamically adjusted to match the instantaneous fluid pressure, ensuring the on-off valve operates at the correct setting pressure and eliminating excessive vibrations and noise.
3Stress or pressure
If the back pressure chamber is connected to control passage with throttles, then pressure control is provided, but pressure fluctuation occurs when liquid is discharged
Solution Approach 1:
The connection valve is preliminarily configured to open when fluid pressure reaches a predetermined level, establishing a direct control path before pressure oscillation can occur. This preliminary action ensures that the back pressure chamber receives stable pressure control from the inlet/outlet passages, preventing pressure fluctuation during liquid discharge.
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 effectively restrains pressure fluctuations and reduces vibrations during motor stoppage by maintaining a constant valve opening pressure and stabilizing the connection valve operation, improving braking consistency and noise reduction.
Implementation Method 1
a pilot passage which is connected to the counter balance valve and introduces a fluid pressure to a back pressure chamber of a connection valve
Implementation Method 2
a counter balance valve which is connected to the first inlet/outlet passage and the second inlet/outlet passage
Data Source
Figure 1
Figure 2
AI summary
A hydraulic motor 100 includes a switching valve 3 which is connected to a pilot passage 54 by which a pressure fluid is introduced into a back pressure chamber 21 of a relief valve 2 and takes a first changeover position 3a where the back pressure chamber 21 is connected to a tank 102 or a second changeover position 3b where the pilot passage 54 is connected to the back pressure chamber 21. By this switching valve 3, the pressure fluid supplied to a hydraulic motor mechanism 1 is introduced into the back pressure chamber 21 via the pilot passage 54 when the hydraulic motor mechanism 1 is in operation, whereas the back pressure chamber 21 is connected to the tank 102 as the pressure in the pilot passage 54 becomes not higher than a predetermined pressure when the hydraulic motor mechanism 1 is being braked.