CVT Oil Passage Switching to Prevent Electric Pump Motor Lockup
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing continuously variable transmission systems face a reduction in the durability of the electric oil pump due to motor lockup during switching operations, which occurs when the hydraulic circuit connected to one port of the electric oil pump is cut off, leading to potential unintended shifting or belt slippage.
Innovation Solution
Incorporating a discharge mechanism, such as a leak oil passage and orifice, between the electric oil pump and the oil passage switching valve to ensure continuous oil discharge and prevent motor lockup, along with an openable and closable leak valve to manage energy consumption, thereby maintaining hydraulic pressure and preventing unintended shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil passage switching valve switches between first and second switching positions to control hydraulic pressure circuits, then the transmission ratio can be changed and fuel consumption is improved, but the motor of the electric oil pump locks up during switching operations, reducing the durability of the electric oil pump
Solution Approach 1:
The discharge mechanism is activated in advance during switching operations to prevent motor lockup. When the switching valve transitions between positions, the discharge mechanism opens a discharge passage beforehand to allow oil to escape, preventing pressure buildup that would cause motor lockup and durability reduction.
Solution Approach 2:
The discharge mechanism acts as an intermediary between the electric oil pump and the hydraulic circuit. It provides a dedicated oil discharge passage with a discharge opening that mediates the oil flow during switching operations, allowing controlled oil discharge to prevent motor lockup while maintaining normal hydraulic circuit operation.
2Adaptability or versatility
If the hydraulic circuit connected to one port of the electric oil pump is cut off during switching, then the switching function is achieved, but the motor locks up causing unintended shifting or belt slippage
Solution Approach 1:
The discharge mechanism serves as an intermediary component that provides an alternative oil discharge path when the main hydraulic circuit is cut off during switching. The discharge passage with its discharge opening allows oil to escape through this intermediary path, preventing motor lockup and ensuring transmission stability during switching operations.
Solution Approach 2:
The discharge mechanism provides a localized oil discharge function specifically at the discharge port area. By creating a localized discharge passage and opening near the discharge port, the system maintains overall switching functionality while providing a specific local path for oil discharge during critical switching moments.
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 effectively prevents motor lockup and maintains hydraulic pressure, enhancing the reliability of the electric oil pump and preventing unintended shifting or belt slippage during switching operations, thus improving the durability and performance of the transmission system.
Implementation Method 1
an electric oil pump disposed in an oil passage between a primary pulley oil chamber and a secondary pulley oil chamber to thereby cause oil to flow into and out of the primary pulley oil chamber
Implementation Method 2
a discharge mechanism in an oil passage between the electric oil pump and the oil passage switching valve for discharging from the oil passage the oil that is discharged from the other discharge port
Data Source
AI summary
A continuously variable transmission includes an electric oil pump disposed in an oil passage between primary and secondary pulley oil chambers. An oil passage switching valve is disposed between the oil pump and the primary pulley oil chamber. The oil passage switching valve switches between a first switching position in which the primary pulley oil chamber and the oil pump are connected, and a second switching position in which the primary pulley oil chamber and the oil pump are disconnected and in which the oil pump and an oil passage connecting an oil reservoir and the oil passage switching valve are connected. In addition, the continuously variable transmission includes a discharge mechanism having a leak valve disposed in the oil passage between the electric oil pump and the oil passage switching valve for discharging oil that is discharged from the oil pump towards the primary pulley oil chamber.