Variable Capacity Pump Device for Discharge Flow Stability
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Solution Overview
Problem
Existing pump devices face challenges in maintaining discharge flow stability when the rotation speed of the drive source decreases, as they often reduce both the driving speed and discharge flow, failing to adapt to varying worker requirements and load conditions effectively.
Innovation Solution
A pump device with a variable capacity first pump, a tilt actuator, a regulator, a fixed capacity second pump, a resistor, and a control actuator, along with an auxiliary passage and switch valve, which allows for adjusting the control pressure and rotation speed to balance differential pressures and maintain discharge flow consistency across varying rotation speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the rotation speed of the drive source is reduced, then energy consumption is lowered, but the discharge flow and driving speed are reduced
Solution Approach 1:
The invention dynamically adjusts the tilt angle of the swash plate based on the rotation speed of the drive source. When rotation speed decreases, the control actuator increases the tilt angle to maintain discharge flow, and when rotation speed increases, it reduces the tilt angle to control discharge flow. This dynamic adjustment resolves the contradiction between energy consumption and productivity.
Solution Approach 2:
The invention changes the operational parameters of the variable capacity pump by adjusting the tilt angle of the swash plate in response to rotation speed changes. The control actuator modifies the tilt angle parameter to compensate for rotation speed variations, maintaining consistent discharge flow while adapting to different energy consumption conditions.
2Productivity
If the tilt angle of the swash plate is increased to maintain discharge flow at lower rotation speeds, then discharge flow is maintained, but the control pressure increases
Solution Approach 1:
The invention employs feedback control where the control actuator continuously monitors the rotation speed of the drive source and adjusts the tilt angle of the swash plate accordingly. This feedback mechanism ensures that discharge flow is maintained while controlling pressure increases through precise, responsive adjustments based on actual operating conditions.
Solution Approach 2:
The control actuator serves as an intermediary between the drive source and the variable capacity pump. It translates rotation speed changes into appropriate tilt angle adjustments, mediating the relationship between speed variations and discharge flow requirements while managing control pressure through controlled intervention.
3Device complexity
If a fixed capacity pump is used to drive the variable capacity pump, then the system is simpler, but the discharge flow cannot be adjusted independently of rotation speed changes
Solution Approach 1:
The invention enables the variable capacity pump to self-adjust its discharge flow based on rotation speed changes through the control actuator. The system uses its own operational parameters (rotation speed) to automatically control its performance, eliminating the need for complex external control systems while maintaining adaptability.
Solution Approach 2:
The control actuator performs multiple functions: it monitors rotation speed, calculates required tilt angle adjustments, and actuates the swash plate control mechanism. This multi-functional component enables discharge flow adjustment independent of rotation speed changes while keeping the overall system relatively simple.
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 device effectively manages discharge flow changes with rotation speed variations, maintaining driving speed and efficiency by balancing differential pressures and adjusting control pressures, thus addressing the issue of reduced discharge flow and driving speed.
Implementation Method 1
a regulator for adjusting the control pressure in accordance with a load pressure of the hydraulic circuit
Implementation Method 2
an actuator driven so as to reduce the control pressure adjusted by the regulator in accordance with the rise of a front-rear differential pressure of the orifice
Implementation Method 3
a switch valve configured to switch between a state in which the auxiliary pressure is supplied to the control actuator through the auxiliary passage and a state in which the auxiliary pressure is shut off
Implementation Method 4
a tilting actuator which reduces a tilting angle of the swash plate in accordance with a rise in a supplied control pressure
Data Source
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AI summary
A pump device 100 includes a tilting actuator 15 for controlling a tilting angle of a swash plate 11 in a variable capacity first pump 10, a regulator 60 for adjusting a control pressure Pcg in accordance with a front-rear differential pressure of a control valve 3, and a control actuator 70 for driving the regulator 60 in accordance with a front-rear differential pressure of a resistor 65 to which the working oil discharged from a fixed capacity second pump 16 is led, and in the control actuator 70, a pressure receiving area of a control piston 71 on which an auxiliary pressure Po against an upstream pressure P3 of the resistor 65 acts is set so that an auxiliary driving force corresponds to a lowered amount of a differential-pressure driving force with switching of a rotation speed of a drive source from a first rotation speed to a second rotation speed.