Hydraulic Circuit Pressure Control Unit with Variable Throttle Valve
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Solution Overview
Problem
Existing hydraulic circuits for controlling actuator driving pressure and utilizing residual oil in construction machines lack linear control capabilities, limiting efficient energy utilization and pressure adjustment.
Innovation Solution
A hydraulic circuit incorporating a variable capacity pump, directional control valve, and a circuit pressure control unit with a variable throttle valve and relief valve, actuated by an electromagnetic mechanism and controlled by a controller, allowing for linear adjustment of setting pressure and efficient use of residual energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a relief valve with auxiliary piston is used to change setting pressure, then the setting pressure can be adjusted between two alternatives (high and low), but linear control of the setting pressure cannot be achieved
Solution Approach 1:
The patent applies the dynamics principle by replacing the static auxiliary piston mechanism with a dynamic variable throttle valve that can continuously adjust its opening degree. This allows the relief valve to transition from discrete pressure settings to continuous linear pressure control, where the throttle valve's opening position dynamically regulates the pilot pressure to achieve proportional pressure adjustment across the full range.
Solution Approach 2:
The patent introduces a variable throttle valve as an intermediary component between the pilot pressure source and the relief valve's pilot chamber. This intermediary device enables linear control by modulating the pilot pressure in proportion to its opening degree, thereby providing smooth and continuous control over the relief valve's setting pressure without the discrete steps inherent in auxiliary piston systems.
2Loss of energy
If residual oil from rotating motor is not efficiently utilized, then the hydraulic circuit can be simplified, but energy efficiency is reduced
Solution Approach 1:
The patent converts the potentially wasted residual oil from the rotating motor into a beneficial resource by routing it through the relief valve to drive a hydraulic motor that generates electricity. The relief valve, originally designed merely to discharge excess pressure, now serves a dual function: controlling pressure and recovering energy from residual oil flow, thereby transforming energy loss into useful electrical power for charging the battery.
Solution Approach 2:
Instead of discarding residual oil from the rotating motor to the tank, the patent implements a recovery system where the residual oil is directed through the relief valve to drive a hydraulic motor connected to an electric generator. This allows the system to recover energy from what would otherwise be wasted fluid flow, converting it into electrical energy that can be stored in the battery for later use.
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 precise linear control of actuator pressure and efficient utilization of residual energy, optimizing energy efficiency and reducing load on hydraulic pumps.
Implementation Method 1
a variable throttle valve (7) and a relief valve (8), and actuated by an electromagnetic mechanism
Implementation Method 2
This relief valve sets a maximum high pressure using a spring force of a spring and controls circuit pressure by communicating the circuit with a tank when a pressure equal to or more than the maximum high pressure is applied
Implementation Method 3
a variable throttle valve disposed in the branch passage upstream of the relief valve
Data Source
AI summary
A circuit pressure control unit includes a relief valve and a variable throttle valve. The relief valve is connected to a connecting passage communicating with an actuator upstream. The variable throttle valve is disposed upstream of the relief valve and is configured to change an opening degree thereof according to a control signal from a controller.