Pump Displacement Control Spool Layout for Faster Response
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Solution Overview
Problem
Existing pump displacement control devices suffer from operational responsiveness issues due to transmission delays and complexity, leading to difficulty in proper control and increased costs due to numerous parts.
Innovation Solution
A pump displacement control device comprising a servo piston, flow rate control spool, power control spool, and a feedback lever with a body portion, connecting pin, and contact pin to regulate control pressure, enhancing operational responsiveness and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a link mechanism including flow rate control lever and power control lever is used to transmit operations of control spools, then control between flow rate control and power control can be selected, but operational responsiveness is deteriorated due to transmission delay caused by play or friction
Solution Approach 1:
The invention extracts and eliminates the intermediate link mechanism (levers) that causes transmission delay. By directly connecting the control spool to the servo piston through a simplified structure, the play and friction in the link mechanism are removed, thereby improving operational responsiveness while maintaining the ability to select between flow rate control and power control modes.
Solution Approach 2:
The invention introduces a new intermediary structure that directly couples the control spool and servo piston without the problematic link mechanism. This new mediator eliminates the transmission delay caused by play and friction in the traditional lever system, allowing direct force transmission while still enabling control mode selection.
2Adaptability or versatility
If a link mechanism with multiple levers is used for control transmission, then control functionality is achieved, but device complexity increases and cost is pushed up
Solution Approach 1:
The invention removes the unnecessary link mechanism components (flow rate control lever, power control lever, and associated linkages) that increase device complexity. By extracting these redundant parts and implementing a direct connection between the control spool and servo piston, the number of parts is reduced while maintaining full control functionality.
Solution Approach 2:
The invention merges the control functions previously distributed across multiple separate levers and linkages into a single integrated control spool structure. This consolidation eliminates the need for multiple discrete components and simplifies the overall device architecture while preserving the ability to perform both flow rate control and power control.
3Adaptability or versatility
If a link mechanism is used for control transmission, then control is achieved, but manufacturing cost increases due to large number of parts
Solution Approach 1:
The invention extracts and eliminates the cost-proly link mechanism components, reducing the total number of parts that require manufacturing, assembly, and quality control. This direct connection approach significantly lowers manufacturing cost while maintaining the essential control capability between flow rate control and power control modes.
Solution Approach 2:
The invention combines multiple separate control components into a single integrated control spool assembly, reducing the number of manufactured parts and simplifying the manufacturing process. This merger reduces material costs, manufacturing complexity, and assembly costs while preserving the full control functionality.
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 precise control of pump displacement with improved responsiveness and reduced manufacturing costs by simplifying the mechanism.
Implementation Method 1
a control pressure regulating spool configured to regulate a control pressure which controls the servo piston corresponding to a displacement of the flow rate control spool and a displacement of the power control spool
Implementation Method 2
a feedback lever including a body portion connected to the servo piston, a connecting pin and a contact pin both of which are fixed to the body portion... the feedback lever is configured to feedback a displacement of the servo piston to the control pressure regulating spool
Implementation Method 3
a flow rate control spool configured to be displaced corresponding to an input pressure; a power control spool configured to be displaced corresponding to a discharge pressure of the pump
Data Source
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AI summary
A pump displacement control device (100) includes: a servo piston (110) that changes a tilt angle; a flow rate control spool (131) that is displaced corresponding to an input pressure; a power control spool (141) that is displaced corresponding to a discharge pressure of the pump (10); a control pressure regulating spool (121) that regulates a control pressure (Pc) which controls the servo piston (110); and a feedback lever (150) connected to the servo piston (110) and the control pressure regulating spool (121). The feedback lever (150) directly abut on either one of the flow rate control spool (131) or the power control spool (141) for regulating the control pressure (Pc).