Electric Pump Actuator Torque Vectoring for Stable Hydraulic Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric pump actuators for continuously variable transmissions in vehicles face challenges with limited power due to 12V electrical voltage, leading to the need for costly voltage converters and produce gear noise and unstable hydraulic pressure due to single motor operation, which results in leakage and oscillating pressure.
Innovation Solution
The use of two electric motors with an electronic control unit that controls the torque vectors to oppose each other, reducing leakage and stabilizing hydraulic pressure by ensuring the gear teeth engage properly, thereby reducing return flow and maintaining constant pressure without expensive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only one electric motor is used to drive the gear wheel pump, then the device complexity is reduced, but the power output is limited to approximately 700W due to 12V electrical voltage constraints
Solution Approach 1:
The pump drive system is segmented into two independent electric motors, each driving one gear wheel. This segmentation allows the system to overcome the power limitation of a single motor while maintaining compatibility with the 12V electrical system, achieving over 1200W total power output without requiring expensive voltage converters.
2Device complexity
If only one electric motor is used to drive the gear wheel pump, then the device complexity is reduced, but gear wheel noises and unstable hydraulic pressure occur due to backlash
Solution Approach 1:
By assigning separate electric motors to each gear wheel, the system can independently control the rotation of each wheel. This independent control eliminates the backlash-induced noise and pressure instability that occurs with single-motor drive, as each motor can precisely maintain its assigned gear wheel's position and speed.
3Power
If two electric motors are used to independently drive each gear wheel, then power output increases to over 1200W, but the cost increases due to requirement of expensive voltage converters
Solution Approach 1:
Instead of converting the voltage from 12V to a higher voltage to increase power, the patent inverts the approach by using two 12V motors that together deliver the required power. This eliminates the need for expensive voltage converters while achieving the same or higher power output.
4Power
If two electric motors are used to independently drive each gear wheel, then power output increases to over 1200W, but the device complexity and cost increase
Solution Approach 1:
The pump is divided into two independently driven gear wheels, each with its own electric motor. This segmentation enables the system to achieve high power output (over 1200W) while maintaining compatibility with standard 12V automotive electrical systems, avoiding the need for complex voltage conversion hardware.
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
This solution efficiently increases power while reducing leakage and maintaining stable hydraulic pressure, improving the reliability and efficiency of the electric pump actuator without increasing costs or complexity.
Implementation Method 1
The electronic control unit (ECU) controls a first electric motor, which is designed to transmit a first torque to the first gear wheel, and controls a second electric motor, which is designed to transmit a second torque to the second gear wheel, in such a manner that the torque vectors of the first torque and of the second torque comprise same rotation directions of the gear wheels
Implementation Method 2
The electric pump actuator (EPA) has a gear wheel pump with two meshing gear wheels, for example an external gear wheel pump that may have a spur toothing arrangement or helical toothing arrangement or spiral toothing arrangement
Data Source
AI summary
An electric pump actuator for a continuously variable transmission includes a gear wheel pump, a first electric motor, a second electric motor, and an electric control unit. The gear wheel pump has a first gear wheel and a second gear wheel meshing with the first gear wheel. The first electric motor is for actuating the first gear wheel, and the second electric motor is for actuating the second gear wheel independent of the first gear wheel. The electronic control unit is arranged to control the first electric motor to transmit a first torque to the first gear wheel, and control the second electric motor to transmit a second torque to the second gear wheel that is set against the first torque in at least one rotation angle range.