Hydraulic Controller Neutral Locking via Unloading Valve
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Solution Overview
Problem
Conventional hydraulic controllers for industrial vehicles risk damage when the operation lever is operated while the spool joint is locked, as the mechanical locking mechanism can be damaged by improper operation.
Innovation Solution
A hydraulic controller for industrial vehicles that includes a hydraulic pump, an actuator, a hydraulic oil passage, a control valve, a position detector, a key switch, and an unloading switching valve, where the controller sets the unloading switching valve to an open state when the key switch is turned ON, preventing the actuator from being operated even when the operation lever is in an operational position, thus avoiding mechanical locking and potential damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical locking mechanism is used to lock the spool joint when the operation lever is in neutral position, then the locking reliability is improved, but the mechanism may be damaged when the operator operates the load handling lever in a locked state
Solution Approach 1:
The controller checks the neutral position of the operation lever before enabling the locking mechanism. By performing this preliminary check, the system ensures that the locking portion only engages when the lever is truly in neutral position, preventing damage that would occur if the lever were operated while locked. This preliminary action resolves the contradiction by adding a safety condition before the locking action occurs.
2Ease of operation
If the locking portion is disengaged from the locked portion to allow operation lever movement, then the ease of operation is improved, but the risk of accidental operation when the vehicle is moving increases
Solution Approach 1:
The controller continuously monitors the position of the operation lever through the position detector and uses this feedback information to control the switching valve. When the lever is detected to be in neutral position, the controller enables the locking mechanism; when the lever moves from neutral, the locking is disabled. This feedback loop allows easy operation when safe while preventing accidental operation when the vehicle is moving, resolving the contradiction between ease of operation and safety.
Data Source
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AI summary
A hydraulic controller (30) for an industrial vehicle (10) includes a hydraulic pump (31) configured to pump hydraulic oil, an actuator (21, 24), a hydraulic oil passage that connects the hydraulic pump (31) and the actuator (21, 24), and a control valve (37) configured to control a flow direction of the hydraulic oil. The hydraulic controller (30) further includes a position detector (27) configured to detect a position of an operation lever (25), a key switch (29), an unloading switching valve (54) that is configured to return the hydraulic oil to a tank (35), and a controller (28). The controller (28) sets the unloading switching valve (54) to an open state when the key switch (29) is turned ON, and sets the unloading switching valve (54) to a closed state when the position detector (27) indicates that the operation lever (25) is in a neutral position.