Work Vehicle Hydraulic Drive Layout With Split Wheel and Actuator Circuits
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Solution Overview
Problem
Existing drive systems for compact hydraulic work vehicles, such as articulated loaders, are sub-optimal and require complex and expensive hydraulic control mechanisms, and there is a need for a simpler and more cost-effective solution that separates wheel drive from actuator operation.
Innovation Solution
A drive system with two distinct hydraulic circuits: one for wheel drive using a first electric motor and hydraulic pump directly coupled to two-way rotors, and another for actuator operation using a second electric motor and hydraulic pump, allowing direct control of wheel rotation and actuator movement independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex hydraulic control mechanism is used to control wheel drive and actuators, then the work vehicle can operate reliably, but the device complexity and cost increase significantly
Solution Approach 1:
The hydraulic system is divided into two separate circuits: a first hydraulic circuit dedicated to wheel drive and a second hydraulic circuit dedicated to actuator operation. This segmentation eliminates the need for complex control mechanisms by assigning specific functions to dedicated circuits, thereby reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The second hydraulic circuit serves multiple functions: it operates all hydraulic actuators and simultaneously controls the filling pressure in the first hydraulic circuit. This multi-functionality reduces the need for separate control mechanisms, simplifying the overall system while ensuring reliable operation.
2Device complexity
If a single hydraulic circuit is used for both wheel drive and actuator operation, then the system construction is simpler, but the control precision and reliability deteriorate
Solution Approach 1:
The hydraulic system is divided into two separate circuits: a first hydraulic circuit dedicated to wheel drive and a second hydraulic circuit dedicated to actuator operation. This segmentation eliminates the need for complex control mechanisms by assigning specific functions to dedicated circuits, thereby reducing overall system complexity while maintaining reliability.
3Ease of operation
If hydraulic control mechanisms are used for wheel drive control, then the control precision is improved, but the cost and device complexity increase
Solution Approach 1:
The patent replaces complex hydraulic control mechanisms with direct electric motor control for the wheel drive system. The first electric motor is directly coupled to the first hydraulic pump, eliminating the need for intermediate hydraulic control mechanisms while maintaining precise control through electronic regulation of motor speed and torque.
4Productivity
If the first hydraulic pump is directly connected to the two-way rotor, then the wheel drive efficiency is improved, but the system becomes more sensitive to pressure fluctuations
Solution Approach 1:
The second hydraulic circuit serves multiple functions: it operates all hydraulic actuators and simultaneously controls the filling pressure in the first hydraulic circuit. This multi-functionality reduces the need for separate control mechanisms, simplifying the overall system while ensuring reliable operation.
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 system simplifies control, reduces costs, and enhances reliability by eliminating complex hydraulic control mechanisms, while maintaining robustness and flexibility, and allows for modular construction with either combustion or electric power options.
Implementation Method 1
a first electric motor which is mechanically coupled to a first hydraulic pump which forms part of a first hydraulic circuit for driving the at least one wheel
Implementation Method 2
a second electric motor which is mechanically coupled to a second hydraulic pump which forms part of a second hydraulic circuit, wherein the second hydraulic circuit is coupled to the first circuit in order to control a hydraulic filling pressure in the first circuit via the second hydraulic circuit
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Drive system for a work vehicle with at least two driven wheels (4) and at least one hydraulic actuator (7, 21, 26), wherein the drive system comprises a first electric motor (1A) which is mechanically coupled to a first hydraulic pump (2) for the purpose of driving the at least two wheels, and wherein the drive system comprises a second electric motor (1B) which is mechanically coupled to a second hydraulic pump (5) for the purpose of driving the at least one hydraulic actuator, wherein the first hydraulic pump is a two-way pump which is connected directly to two-way rotors at the wheels so that a rotation of the two-way pump is proportionally transferred to the wheels, and wherein the first electric motor is provided with a controller for controlling the electric motor on the basis of a first input which relates to a desired displacement of the work vehicle.