Power Braking System With Single Relay Valve And Shuttle Valve
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Solution Overview
Problem
Existing power braking systems for tractors are complex and expensive due to the use of separate relay valves for left and right brakes, leading to uneven brake pressures when both pedals are operated, causing yawing movements and decreased stability.
Innovation Solution
A power braking system with a single relay valve and interconnected pilot lines via a shuttle valve ensures that both brakes receive the same proportional pressure, eliminating the need for separate relay valves and preventing uneven pressure application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate relay valves are used for left and right brakes, then each brake can be controlled independently for steering assistance, but the system complexity and cost increase
Solution Approach 1:
The patent combines two separate relay valves into a single relay valve that controls both left and right brakes. This single relay valve receives pilot pressures from both brake pedals and independently controls the left and right shift valves, thereby reducing system complexity and cost while maintaining the capability to provide steering assistance through independent brake control.
Solution Approach 2:
The single relay valve performs multiple functions: it receives pilot pressures from both left and right brake pedals, determines the highest pilot pressure, and uses this pressure to control both left and right shift valves. This multi-functional design eliminates the need for separate relay valves while preserving independent brake control capability for steering assistance.
2Ease of operation
If separate relay valves are used for left and right brakes, then each brake receives proportional pressure, but uneven pressures occur when both pedals are operated causing yawing movement
Solution Approach 1:
The patent ensures equal brake pressures by connecting both pilot lines to a common relay valve through a shuttle valve. The shuttle valve selects the highest pilot pressure and applies it to the relay valve, ensuring that both left and right brakes receive the same proportional pressure when both pedals are operated, thereby preventing yawing movement and maintaining tractor stability.
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
The system simplifies the braking system, reduces costs, and maintains stability by ensuring equal brake pressures during operation, eliminating yawing and improving tractor stability.
Implementation Method 1
the pilot lines are interconnected via a shuttle valve so that the highest pilot pressure generated by operating the brake pedals is applied to the single relay valve
Implementation Method 2
the highest pilot pressure generated by operating the brake pedals is applied to the single relay valve
Implementation Method 3
the relay valve means delivering a brake operating pressure proportional to the depression of the associated brake operating pedal
Data Source
Figure 1
Figure 2
AI summary
A vehicle power braking system has separate left and right brakes (11, 12) operable from a source of pressurised fluid (13) via relay valve means (16) controlled by separate left and right brake operating pedals (14, 15) to provide steering assistance during a turn. The relay valve means delivers a brake operating pressure proportional to the depression of the associated brake operating pedal to separate left and right shift valves (17, 18), each shift valve being connected with its respective operating pedal (14, 15) by a respective pilot line (19, 20) so that when each pedal is operated the associated shift valve is opened by the respective pilot line pressure to supply the proportional pressure from the relay valve means to the respective brake(11, 12). The relay valve means comprises a single relay valve (16) which supplies both shift valves (17, 18) and the pilot lines (19, 20) are interconnected via a shuttle valve (21, 22) so that the highest pilot pressure generated by operating the brake pedals (14, 15) is applied to the single relay valve (16) so that each shift valve receives the same brake applying pressure proportional to said highest pilot pressure.