Tractor Hydraulic Pump Split Layout for Steering Flow Priority
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Solution Overview
Problem
The load sensing system for tractors is complex and large in size, leading to issues with compactness, as it prioritizes hydraulic fluid supply to actuators with low loads, potentially causing insufficient supply to traveling-power-transmission and steering systems, and requires multiple priority valves, which increases complexity and size further.
Innovation Solution
A working vehicle configuration that combines a load sensing system with a fixed displacement pump and an open center system, where a variable displacement pump is used for working-machine-related actuators and a fixed displacement pump is used for traveling-power-transmission and steering-related actuators, with priority valves managed to ensure consistent fluid supply without excessive complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a load sensing system is used to control hydraulic actuators, then energy saving and low heat generation are achieved, but the circuit becomes complicated and the system configuration increases in size
Solution Approach 1:
The hydraulic system is divided into two separate systems: a load sensing hydraulic system for working-machine-related actuators and an open center hydraulic system for traveling-power-transmission and steering actuators. This segmentation allows each system to operate with its own fixed displacement pump, eliminating the need for complex priority valves and flow distribution mechanisms while maintaining the energy efficiency benefits of load sensing control where needed.
2Reliability
If multiple priority valves are mounted to ensure hydraulic fluid supply to traveling-power-transmission and steering actuators, then sufficient fluid supply is guaranteed, but the number of valves increases and the circuit configuration becomes more complicated
Solution Approach 1:
The hydraulic system is divided into two separate systems: a load sensing hydraulic system for working-machine-related actuators and an open center hydraulic system for traveling-power-transmission and steering actuators. This segmentation allows each system to operate with its own fixed displacement pump, eliminating the need for complex priority valves and flow distribution mechanisms while maintaining the energy efficiency benefits of load sensing control where needed.
3Productivity
If a single variable displacement pump is used for all hydraulic actuators, then flow rate control is optimized, but the system configuration increases in size and cannot be mounted on compact tractors
Solution Approach 1:
The hydraulic system is divided into two separate systems: a load sensing hydraulic system for working-machine-related actuators and an open center hydraulic system for traveling-power-transmission and steering actuators. This segmentation allows each system to operate with its own fixed displacement pump, eliminating the need for complex priority valves and flow distribution mechanisms while maintaining the energy efficiency benefits of load sensing control where needed.
Solution Approach 2:
The variable displacement mechanism is extracted from the hydraulic pump and applied only to the working-machine-related hydraulic system, while the traveling-power-transmission and steering systems use simple fixed displacement pumps. This extraction reduces overall system complexity and size while maintaining optimized flow control where it is most needed for productivity.
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 configuration simplifies the hydraulic system, reduces the number of priority valves, and allows for a compact tractor design by ensuring consistent hydraulic fluid supply to all systems, addressing the complexity and size issues of traditional load sensing systems.
Implementation Method 1
a first hydraulic pump which is a variable displacement pump with a delivery flow rate controlled by load sensing control
Implementation Method 2
hydraulic fluid is supplied to a hydraulic actuator and a controller to control the hydraulic actuator
Data Source
AI summary
A working vehicle includes a first hydraulic pump (e.g., a variable displacement pump) with a delivery flow rate controlled by load sensing control, a second hydraulic pump (e.g., a fixed displacement pump), at least one working-machine-related control valve to control at least one working-machine-related hydraulic actuator, a power shift valve to control at least one traveling-power-transmission-related hydraulic actuator, and a power steering controller to control a steering-related hydraulic actuator. The at least one working-machine-related control valve is provided in a first hydraulic system supplied with hydraulic fluid by the first hydraulic pump, and at least one of the power shift valve or the power steering controller is provided in a second hydraulic system supplied with hydraulic fluid by the second hydraulic pump.