Hydrostatic Drive Pump Switching to Cut Throttling Losses
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Solution Overview
Problem
Existing hydrostatic drive systems with 2Q-constant pumps and changeover valves suffer from high throttling losses, no-load losses, and lack energy recovery, leading to noise emissions and reduced service life due to impacts and vibrations.
Innovation Solution
A hydrostatic drive system featuring a constant pump configured to provide at least two and at most three pumping states, coupled with a switching device and switching valve to manage the pumping states and provide a switching pressure for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a 2Q-constant pump with changeover valve is used, then the drive system has high dynamics and low cost, but it produces throttling losses, no-load losses, and causes impacts and vibrations
Solution Approach 1:
The invention extracts the changeover valve from the system by using a 4Q-constant pump that can directly switch flow direction internally. The pump's internal mechanism allows volume flow to be switched to either the A side or B side of the hydraulic cylinder without external switching valves, eliminating throttling losses and no-load losses associated with valve operations.
Solution Approach 2:
The 4Q-constant pump performs multiple functions: it acts as both a pumping device and a directional control device. The pump can deliver volume flow in four quadrants (positive/negative direction × loading/unloading), combining the functions of a constant pump and a changeover valve into a single component, thereby eliminating energy losses.
2Device complexity
If a 2Q-constant pump with changeover valve is used, then the drive system has simple structure, but it generates noise emissions and reduces service life due to impacts and vibrations
Solution Approach 1:
The changeover valve is removed from the system and its function is integrated into the 4Q-constant pump. This eliminates the mechanical switching actions that cause impacts and vibrations, thereby reducing noise emissions and extending service life while maintaining structural simplicity.
Solution Approach 2:
The 4Q-constant pump enables dynamic switching of volume flow direction without mechanical impact. The pump can continuously adjust the direction of volume flow delivery to either the A side or B side, allowing smooth transitions that avoid the impacts and vibrations generated by traditional changeover valves.
3Adaptability or versatility
If a 2Q-variable displacement pump with changeover valve is used, then volume flow can be adapted continuously, but the system becomes more cost-intensive and requires larger tank volume
Solution Approach 1:
The 4Q-constant pump combines the functions of a variable displacement pump and a changeover valve into a single component. The pump can deliver volume flow in four quadrants (positive/negative direction × loading/unloading), providing continuous volume flow adaptation without requiring separate variable displacement mechanisms or changeover valves, thereby reducing component cost and tank volume requirements.
4Adaptability or versatility
If a 4Q-variable displacement pump with proportional valve is used, then any volume flow between -Qmax and +Qmax can be activated, but the system becomes complex and cost-intensive with losses due to the proportional valve
Solution Approach 1:
The proportional valve is removed from the system. The 4Q-constant pump directly controls volume flow delivery to either the A side or B side of the hydraulic cylinder through its internal switching mechanism, eliminating the need for external proportional valves and their associated throttling losses.
Solution Approach 2:
The 4Q-constant pump performs both pumping and proportional control functions internally. It can deliver any volume flow between -Qmax and +Qmax by switching between its four operating quadrants, combining the functions of a variable displacement pump and a proportional valve into a single loss-free component.
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 system achieves good energy efficiency, rapid direction changes, reduced noise emissions, and extended service life by eliminating the need for friction elements and allowing continuous transfer between pumping states without abrupt changes.
Implementation Method 1
The constant pump (3) is configured to provide at least two and at most three pumping states for pumping a volume flow
Implementation Method 2
a switching pressure is provided via the switching valve (4) for switching the switching member (6)
Data Source
AI summary
A hydrostatic drive system, and methods of making and using same, including a constant pump configured to provide at least two and at most three pumping states for pumping a corresponding volume flow. A switching device has a switching valve and a switching member, wherein a switching pressure is provided via the switching valve for switching the switching member, and wherein the switching member is configured, on the basis of the switching pressure, to switch the constant pump into one of the pumping states and to provide the corresponding volume flow to the hydraulic cylinder.