Wheel Loader Brake Pressure Control for Flexible Pedal Response
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Solution Overview
Problem
Existing brake control systems for work vehicles, such as wheel loaders, face challenges in providing flexible brake performance during dump approach operations due to the need for specific hardware configurations based on vehicle specifications and load weights, making it difficult to satisfy user demands effectively.
Innovation Solution
A brake control system that incorporates a controller with multiple control characteristics and a solenoid switching valve to adjust brake valve control pressure based on pedal angle, allowing for flexible brake performance adjustments without requiring extensive hardware changes, combining electronic and hydraulic brake control for enhanced responsiveness and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the brake control device is configured with a control section that merely controls the brake based on the operation signal from the operation section, then the hardware configuration remains simple, but the brake performance cannot be flexibly adjusted to satisfy different user demands
Solution Approach 1:
The patent applies dynamics by making the brake control characteristics changeable through a solenoid switching valve that can switch between first and second control characteristics based on operating conditions. This allows the system to adapt brake performance dynamically without changing hardware configuration, resolving the contradiction between adaptability and device complexity
Solution Approach 2:
The patent changes the control parameter (brake valve control pressure) based on pedal angle and switching conditions. By varying the control characteristics through the solenoid switching valve, the system achieves flexible brake performance adjustment without hardware modifications, addressing the contradiction between adaptability and simplicity
2Reliability
If special brakes are mounted to satisfy specific brake performance requirements, then the brake performance can be optimized for specific conditions, but the number of parts increases and special setting is required for each vehicle body
Solution Approach 1:
The patent makes a single brake system perform multiple functions by incorporating a solenoid switching valve that enables different control characteristics. This universal approach eliminates the need for multiple specialized brakes, reducing part count while maintaining reliable brake performance across different conditions
Solution Approach 2:
Instead of using different physical brakes for different performance requirements, the patent creates virtual copies of brake control characteristics through software/control logic in the solenoid switching valve. This allows multiple brake performance profiles to be achieved without duplicating hardware components
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
Enables flexible and accurate brake performance adjustments, ensuring safe and efficient dump approach operations by adapting to varying vehicle and load conditions, while maintaining system reliability even in case of electrical abnormalities.
Implementation Method 1
a solenoid switching valve configured to switch, when a pedal angle is equal to or less than a predetermined pedal angle, between a first control characteristic in which a brake valve control pressure is increased as the pedal angle increases and a second control characteristic in which the brake valve control pressure is not increased as the pedal angle increases
Data Source
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AI summary
Provided is a work vehicle capable of satisfying a user's demand to brake performance in a flexible manner. A wheel loader 1 comprises a controller 5 storing a plurality of control characteristics each of which is set such that a brake valve control pressure Pi of a solenoid proportional valve 45 increases as a pedal angle θ of a brake pedal 43 increases, and under the condition where a pedal angle θ is equal to or less than a predetermined pedal angle θ, an increase rate of the brake valve control pressure Pi with respect to the pedal angle θ varies. In a case where the pedal angle θ detected by a potentiometer 33 is equal to or less than the predetermined pedal angle θth, the controller 5, calculates the brake valve control pressure Pi based on the selected one control characteristic.