Variable Displacement Hydraulic Pump Torque Control
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Solution Overview
Problem
The existing working machines experience operability issues due to swinging of the machine body when the maximum absorption torque setting value is switched, particularly when the operator is in the intermediate position of the lever stroke, leading to a relative movement of the operation lever with respect to the machine body, which affects the machine's stability and performance.
Innovation Solution
The implementation of a system that includes a variable displacement hydraulic pump with specific torque setting positions (E1, E2, and P) and detectors for full operation detection, allowing automatic switching to E1 position when either the travelling or boom operation is fully engaged, and enabling manual switching between E2 and P positions, optimizing torque settings for improved operability and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the maximum absorption torque setting value is switched during intermediate lever operation, then the discharge amount of hydraulic pump is changed to improve performance, but the machine body swings violently affecting operability
Solution Approach 1:
The control unit detects full operation of travel or boom before the operation terminal position is reached, and switches the maximum absorption torque setting value to E1 position in advance. This preliminary switching prevents violent machine body swinging during intermediate lever operation while maintaining high discharge amount when needed.
2Speed
If the maximum absorption torque setting value is switched, then the hydraulic pump discharge amount changes to improve speed characteristics, but the machine body acts violently
Solution Approach 1:
The control unit continuously monitors the operation state through detectors that sense full operation of travel and boom. Based on this feedback, the control unit automatically switches the maximum absorption torque setting value between E2 and E1 positions, maintaining machine body stability while achieving required speed characteristics.
3Ease of operation
If automatic switching is implemented to prevent machine body swinging, then operability is improved, but the system complexity increases
Solution Approach 1:
The control unit automatically detects full operation states through detectors and switches the maximum absorption torque setting value without operator intervention. This self-service approach improves operability by preventing machine body swinging while keeping the control interface simple for the operator.
Data Source
AI summary
A working machine rendered to change in setting a maximum value of an absorption torque of hydraulic pump to a rather high value when the working machine is in a specified state, solves problems that, when an operation lever is being operated in an intermediate position of a lever stroke, there occurs a swinging in a machine body due to change-over of a maximum absorption torque setting value so that the operation lever is relatively moved with respect to the machine body to exert an influence on operability and the machine body acting violently. When the maximum absorption torque setting value is E2 position which is good fuel efficiency, upon detection of a full operation of either one or both of the travelling operation member and the boom operation member, controlling to automatically switch to E1 position of a maximum absorption torque larger than that of E2 position is performed.