Working Machine Hydraulic Shift Shock Control
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Solution Overview
Problem
Existing hydraulic systems for working machines, such as skid-steer loaders and backhoes, face challenges in reducing shift shock effectively during speed changes, especially when the machine is in a turn traveling state, due to difficulties in accurately determining whether the machine is in a straight or turn traveling state.
Innovation Solution
The system includes a prime mover, traveling pumps, motors, a determiner to assess the traveling state based on motor revolutions and directions, and a controller that adjusts hydraulic fluid supply to reduce shift shock by modifying the rotation speed and hydraulic fluid pressure according to the determined state, using a control map for precise adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the system uses a single shift shock reduction method based only on traveling speed, then the system structure remains simple, but the shift shock cannot be reduced appropriately when the machine body is in a turn traveling state
Solution Approach 1:
The system changes the parameters used for shift shock reduction control from only traveling speed to a combination of traveling speed and traveling state (straight or turn). The controller selects different reduction amounts based on the detected traveling state, allowing appropriate shift shock reduction in both straight and turn traveling conditions.
Solution Approach 2:
The system dynamically adjusts the shift shock reduction strategy based on the current traveling state. By continuously monitoring whether the machine is in straight or turn traveling and adapting the reduction amount accordingly, the system optimizes performance for varying operational conditions.
2Measurement precision
If the system does not accurately determine the traveling state, then the control system remains simple, but appropriate shift shock reduction cannot be achieved for different traveling states
Solution Approach 1:
The system uses feedback from detectors that monitor the rotation speeds of left and right traveling motors to determine the traveling state. This feedback mechanism enables accurate distinction between straight and turn traveling states, which then informs the appropriate shift shock reduction control strategy.
Solution Approach 2:
The system replaces complex mechanical state detection with a control-based determination method. By using the controller to calculate traveling state based on motor rotation speed differences, the system achieves accurate state detection without adding complex mechanical sensing components.
3Object-generated harmful factors
If the system reduces hydraulic fluid supply during shift operations, then shift shock is reduced, but the rotation speed of traveling motors may be insufficient in turn traveling state
Solution Approach 1:
The system changes the control parameter from a fixed hydraulic fluid supply reduction to a variable reduction amount based on traveling state. In turn traveling state, the system reduces the reduction amount or maintains normal supply to ensure sufficient motor speed, while in straight traveling state, full reduction is applied to minimize shift shock.
Solution Approach 2:
The hydraulic fluid supply control is made dynamic by continuously adjusting the reduction amount according to the detected traveling state. This dynamic adjustment ensures that shift shock is minimized when appropriate while maintaining sufficient motor speed when needed for turn traveling operations.
Data Source
AI summary
A working machine includes first and second traveling pumps, an acquirer to acquire the number of revolutions and the rotation direction of each of first and second traveling motors, a determiner to, based on the acquired number of revolutions and the acquired rotation direction, determine whether a machine body is in a straight traveling state or a turn traveling state, and a controller configured or programmed to, when switching from a first state allowing rotation speeds of the first and second traveling motors to increase up to a first maximum speed, to a second state allowing the rotation speeds to increase up to a second maximum speed higher than the first maximum speed, or vice versa, is performed, reduce an amount of hydraulic fluid supply from the pumps to the motors according to the straight traveling state or the turn traveling state of the machine body.