Hydraulic Shift-By-Wire Transmission Manual Override Valve Layout
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Solution Overview
Problem
Existing shift-by-wire transmission systems in vehicles face challenges in enabling easy manual control, particularly in cases of abnormality where the controller's actuator force is insufficient to open or close valves against its force, making manual intervention difficult and requiring excessive force.
Innovation Solution
A hydraulic mechanism with a second valve that is manually drivable and switchable between automatic and manual control states, allowing operating oil to be delivered to the transmission without flowing through the primary valve, enabling manual control of the transmission even if the controller fails, using a second valve positioned closer to the main oil passage than the first valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a shift-by-wire transmission system with controller actuation is used, then automatic control capability is improved, but manual control capability deteriorates when controller fails or actuator force is insufficient
Solution Approach 1:
The oil passage is segmented into a first oil passage for automatic control and a second oil passage for manual control, allowing independent operation of each control mode without interference from the controller or actuator
Solution Approach 2:
A manual operation lever acts as an intermediary to directly manipulate the second spool valve, bypassing the controller and actuator system to provide manual control capability when automatic control fails
2Ease of operation
If manual lever is used to override controller actuator force, then manual control capability is improved, but required manual force increases excessively
Solution Approach 1:
The valve control system is segmented into two independent pathways: one controlled by the actuator through the first spool valve, and another controlled directly by the manual lever through the second spool valve, allowing manual control without opposing actuator force
Solution Approach 2:
The manual control pathway is extracted as a separate oil passage (second oil passage) that bypasses the actuator-controlled first spool valve, eliminating the need to overcome actuator force during manual operation
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
Facilitates easy manual control of the transmission during abnormalities, allowing the vehicle to operate with limited functions and travel to a repair location without the need for excessive manual force or enlarged levers, thereby avoiding complete immobilization.
Implementation Method 1
The transmission is shiftable by hydraulic pressure. The main oil passage is configured to deliver operating oil.
Data Source
AI summary
A vehicle includes a transmission shiftable by hydraulic pressure, a main oil passage that delivers operating oil, a first oil passage that delivers the operating oil from the main oil passage to the transmission, a first valve that opens/closes the first oil passage, a controller that controls the first valve, a second oil passage that delivers the operating oil from the main oil passage to the transmission, and a manually drivable second valve that opens/closes a section of the first oil passage that is closer to the main oil passage than the first valve and the second oil passage. The second valve is switchable between the automatic control state in which the first oil passage is opened and the second oil passage is closed and the manual control state in which the first oil passage is closed and the second oil passage is opened.