Three-Point Hitch Check Valve Layout for Air-Free Response
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Solution Overview
Problem
Air ingress into hydraulic systems of three-point hitches in agricultural machinery causes delayed hitch performance due to the need for air compression, particularly in single-acting hydraulic cylinders where the acting side drains above the oil level, leading to inefficiencies in raising and lowering operations.
Innovation Solution
A hydraulic system with check valves configured to prevent air ingress by positioning them above and below the hydraulic fluid level in the reservoir, ensuring only hydraulic fluid flows into the hitch cylinders, even during neutral and float positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the hitch drains to the tank above oil level in single-acting hydraulic cylinders, then the system structure is simplified, but air ingress occurs causing delayed hitch response
Solution Approach 1:
A check valve is introduced as an intermediary component in the drain line between the hitch cylinder and the reservoir. This check valve allows hydraulic fluid to drain from the cylinder to the reservoir while preventing air from the reservoir from entering the cylinder, thus eliminating the delayed hitch response caused by air compression while maintaining the simplified above-oil-level drainage configuration
2Ease of operation
If the hitch is in float position and forced up, then the hitch can move freely, but air is pulled into the system from the tank
Solution Approach 1:
The check valve acts as a mediator that permits the hitch to move freely in float position while blocking the path for air ingress. When the hitch moves up in float position, the check valve closes to prevent air from being sucked into the cylinder through the drain line, maintaining hydraulic system reliability
3Force
If the hitch moves up in neutral position, then the hitch can overcome load, but suction opens check valve and pulls air from tank
Solution Approach 1:
The check valve in the drain line serves as a mediator that allows the hitch to generate sufficient lifting force by enabling fluid suction during upward motion, while simultaneously preventing air from the reservoir from entering the hydraulic system through the same suction path
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
Maintains normal hitch operation by preventing air ingress, thereby eliminating delays in raising and lowering operations and ensuring efficient performance of three-point hitches.
Implementation Method 1
A first check valve is disposed along the second flow path between the first flow path and the reservoir, wherein the first check valve is configured to keep air from entering the hydraulic system via the second flow path from the reservoir
Data Source
AI summary
A hydraulic system for a three-point hitch includes at least one hitch cylinder and a first flow path. The hydraulic system includes a hitch valve fluidly coupled to the at least one hitch cylinder via the first flow path, wherein the hitch valve is configured to control a flow of hydraulic fluid to the at least one hitch cylinder. The hydraulic system includes a second flow path fluidly coupled to the first flow path at a first location between the at least one hitch cylinder and the hitch valve, wherein the second flow path is fluidly coupled to a reservoir for the hydraulic fluid. The hydraulic system includes a first check valve disposed along the second flow path between the first flow path and the reservoir, wherein the first check valve is configured to keep air from entering the hydraulic system via the second flow path from the reservoir.