Variable Displacement Pump Hydraulic Drive for Combine Harvester Fan
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Solution Overview
Problem
Existing hydraulic drive systems for the cleaning fan in combine harvesters suffer from energy inefficiency and mechanical complexity, particularly due to the use of controllable valves that lead to significant energy losses.
Innovation Solution
A drive system utilizing a variable displacement pump with an electronically actuated hydraulic control system, operating in an open loop circuit without a flow regulating valve, to control the fan speed by adjusting the pump displacement electronically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a controllable valve is used to regulate hydraulic liquid flow to the motor, then fan speed can be regulated, but significant energy loss occurs due to dissipation of non-used hydraulic energy
Solution Approach 1:
The invention removes the flow-regulating valve from the hydraulic circuit between the pump and motor. Instead of using a valve to control flow rate, the system extracts only the necessary flow control function by adjusting the pump's displacement volume, allowing the full hydraulic flow to be utilized productively without dissipation through valve throttling.
Solution Approach 2:
The invention changes the control parameter from flow rate regulation (via valve opening) to displacement volume regulation (via pump adjustment). By varying the pump's displacement parameter electronically, the system achieves fan speed control while maintaining optimal hydraulic energy utilization, avoiding the energy losses inherent in flow-regulating valves.
2Ease of operation
If a variable displacement pump with electronically controlled valve system is used, then fan speed control is achieved, but mechanical complexity increases
Solution Approach 1:
The invention simplifies the hydraulic circuit by removing the external flow-regulating valve and associated control mechanisms. The system extracts only the essential displacement control function from the pump, eliminating unnecessary mechanical components and reducing overall system complexity while maintaining speed control capability.
Solution Approach 2:
The invention replaces complex mechanical valve control systems with electronic displacement control of the pump. By using electronic actuators to adjust pump displacement directly, the system eliminates the need for mechanical flow-regulating valves and their associated linkages, reducing mechanical complexity while achieving precise fan speed control.
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
This solution achieves a gain in energy efficiency with reduced mechanical complexity, allowing for precise control of fan speed with less energy loss compared to traditional systems.
Implementation Method 1
The pump is a variable displacement pump configured to produce a flow of hydraulic liquid to the motor
Implementation Method 2
a hydraulic motor, both having an inlet port and an outlet port, the motor being a fixed displacement motor coupled to the cleaning fan for rotationally driving said fan
Data Source
Figure 1~2
Figure 3~4
AI summary
The drive system comprises a hydraulic pump and a hydraulic motor, both having an inlet port and an outlet port, the motor being a fixed displacement motor directly coupled to the cleaning fan for rotationally driving said fan, the pump being a variable displacement pump configured to produce a flow of hydraulic liquid to the motor. In a system according to the invention, the outlet port of the pump is coupled to the inlet port of the motor by a hydraulic line, wherein said line does not comprise a valve for regulating a flow of hydraulic liquid to the motor. In the system of the invention, the flow to the motor is not regulated through a flow regulating valve between pump and motor, but by changing the pump displacement electronically. To this aim, the pump includes an electronically actuated hydraulic control system for controlling the pump displacement regardless of the hydraulic pressure of the liquid in the hydraulic line between the pump and the motor. The pump and the motor are part of an open hydraulic circuit.