Travel Motor Speed Shift Control for Reduced Hydraulic Shock
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Solution Overview
Problem
Conventional working machines experience shift shock during acceleration and deceleration due to the need for additional components like bleed fluid lines to reduce shock, which increases the number of parts and complexity.
Innovation Solution
A working machine with a prime mover, traveling pump, and traveling motor that includes a controller for shock-mitigation control, adjusting the rotation speed of the prime mover and actuation valve to reduce shift shock by changing the reduction rate over a defined period, thereby simplifying the reduction of shift shock without adding extra components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a bleed fluid line is provided to the pressure-receiving portion of the hydraulic change-over valve to reduce shift shock, then the shift shock is reduced, but the number of parts increases
Solution Approach 1:
The patent merges the shock reduction function into the existing hydraulic change-over valve by providing a pressure-receiving portion that directly communicates with the bleed fluid line through the valve's internal structure. This integration eliminates the need for separate shock reduction components while maintaining the shock mitigation effect.
Solution Approach 2:
The hydraulic change-over valve performs dual functions: it controls the switching between hydraulic circuits and simultaneously reduces shift shock through its pressure-receiving portion. The valve uses its own internal pressure dynamics to mitigate shock without requiring external intervention or additional active components.
2Object-affected harmful factors
If additional components are added to reduce shift shock, then the shift shock is reduced, but the hydraulic system complexity increases
Solution Approach 1:
The hydraulic change-over valve is designed to perform multiple functions: circuit switching and shock reduction. The pressure-receiving portion enables the valve to utilize hydraulic pressure dynamics for shock mitigation while maintaining its primary switching function, thereby reducing overall system complexity.
Solution Approach 2:
The pressure-receiving portion acts as an intermediary element within the hydraulic change-over valve that mediates between the hydraulic circuit switching function and the shock reduction requirement. It translates pressure changes into shock-mitigating effects without requiring separate mediation components.
Data Source
AI summary
In a working machine, a traveling pump is driven by a prime mover to rotate a traveling motor by fluid therefrom. The traveling motor has a rotation speed shiftable between a lower first speed and a higher second speed. A traveling change-over valve is shiftable between a first state where the rotation speed of the traveling motor is set to the first speed and a second state where the rotation speed of the traveling motor is set to the second speed. A controller performs a shock-mitigation for reducing a rotation speed of the prime mover when the traveling change-over valve is shifted from the second state to the first state. The controller determines a reduction amount of rotation speed of the prime mover reduced by the shock mitigation based on a difference between a target rotation speed of the prime mover and an actual rotation speed of the prime mover.