Split-Flow Hydraulic Pump Control With a Single Pressure Gauge
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Solution Overview
Problem
Conventional hydraulic drive devices for mini excavators require multiple pressure gauges to accurately control pump absorption horsepower, leading to increased costs, which is undesirable for inexpensive devices.
Innovation Solution
A fluid pressure drive device with a single swash plate and pressure detection unit that controls discharge flow rates based on intermediate pressure at a merging point, eliminating the need for multiple pressure gauges and allowing for accurate calculation of pump absorption torque and horsepower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pressure gauges are provided at each discharge port to accurately control pump absorption horsepower, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple pressure detection functions into a single pressure gauge by connecting it to a common passage that receives fluid from both discharge ports. This single pressure gauge measures the combined pressure, eliminating the need for multiple separate pressure gauges while maintaining the capability to control pump absorption horsepower accurately.
Solution Approach 2:
The single pressure gauge serves multiple functions by detecting pressure from both discharge ports simultaneously through the common passage. This multi-functional approach allows one device to perform what previously required multiple separate devices, reducing system complexity while preserving measurement accuracy for horsepower control.
2Ease of operation
If computerization is implemented to accurately control pump absorption horsepower, then control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a common passage as an intermediary element that simplifies the connection between the dual discharge ports and the single pressure gauge. This intermediary structure enables accurate pressure measurement for computerized horsepower control without requiring complex multi-gauge instrumentation systems, thereby reducing overall device complexity while maintaining control precision.
3Device complexity
If a single pressure detection unit is used to detect intermediate pressure at a merging point, then device complexity is reduced, but measurement precision may be compromised
Solution Approach 1:
The patent segments the fluid flow paths by introducing a common passage that separately combines pressures from both discharge ports before measurement. This segmentation approach allows the single pressure detection unit to measure the combined pressure accurately without being subjected to the complexities of simultaneously measuring multiple separate pressure points, thereby maintaining measurement precision while reducing device complexity.
Data Source
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AI summary
A hydraulic drive device includes a main pump (15) and a single pressure gauge (11). The main pump (15) controls discharge flow rates of a first hydraulic oil and a second hydraulic oil discharged into two or more first pressure oil supply passage (120) and second pressure oil supply passage (121) with a single swash plate (23). The main pump (15) is a swash plate variable displacement type split flow hydraulic pump. The pressure gauge (11) measures an intermediate pressure of the discharged fluid at a merging point (123a) between the first pressure oil supply passage (120) and the second pressure oil supply passage (121). The discharge flow rates are controlled based on a pressure value obtained by the pressure gauge (11).