Brushless Hydraulic Pump Bypass Control to Prevent Start Failures
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Solution Overview
Problem
Hydraulic devices in working machines, such as trucks, face durability issues due to the limited lifespan of DC brush motors and reliability problems when using brushless motors, including start failures and pressurization issues.
Innovation Solution
A hydraulic device configuration that includes a fluid storage portion, a brushless motor-driven fluid supply portion, a bypass flow path with a switchable valve, and a backflow prevention valve, along with a control system that manages the bypass flow path's state changes based on the motor's operation, ensuring reliable operation and durability by preventing backflow and pressurization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC brush motor is used as the electric motor, then the hydraulic device can operate reliably, but the durability is limited by the brush lifespan
Solution Approach 1:
The patent replaces the DC brush motor with a brushless motor, substituting a mechanical system with brushes and commutators with an electronic control system. This eliminates the wear-prone brush components while maintaining motor functionality, thereby improving durability without sacrificing operational reliability
2Duration of action of stationary object
If a brushless motor is used instead of a brush motor, then durability is improved, but start failures and pressurization issues occur
Solution Approach 1:
The patent introduces a bypass flow path that activates before the brushless motor starts operating. This preliminary action allows the hydraulic system to establish proper pressure and flow conditions in advance, preventing start failures and pressurization issues that would otherwise occur with brushless motor operation
3Duration of action of stationary object
If a brushless motor is used, then the brush lifespan limitation is eliminated, but pressurization in pipes occurs when the motor is stopped
Solution Approach 1:
The patent introduces a bypass flow path as an intermediary component between the pump and hydraulic system. This mediator provides an alternative flow route that prevents pressure buildup in the pipes when the brushless motor stops, eliminating the harmful pressurization effect while maintaining the durability benefits of the brushless motor
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 solution enhances the reliability and durability of hydraulic devices by preventing start failures and pressurization, allowing for smooth operation with a brushless motor, even without position sensors, and reduces the burden on pipes, thereby improving overall performance.
Implementation Method 1
a backflow prevention valve which prevents backflow of the working fluid from the power output portion to the bypass flow path portion
Implementation Method 2
a hydraulic cylinder, a pump and an electric motor... the pump supplies working liquid to the hydraulic cylinder which actuates a support arm
Data Source
AI summary
A hydraulic device is provided. Working fluid stored in a fluid storage portion is supplied by a fluid supply portion to a power output portion. The fluid supply portion is driven by a brushless motor. A bypass flow path portion can be switched between a first state of supplying the working fluid from the fluid supply portion to the fluid storage portion and a second state of blocking the fluid supply portion from the fluid storage portion. A control to switch the bypass flow path portion from the first state to the second state after the brushless motor is started and a control to switch the bypass flow path portion from the second state to the first state when the brushless motor is stopped is performed. Backflow of the working fluid from the power output portion to the bypass flow path portion is prevented by a backflow prevention valve.