Freewheel Mechanism in Transmission Fluid Pump Drive
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Solution Overview
Problem
Existing motor vehicle transmission fluid pumps require continuous operation of the electric motor when the internal combustion engine rotates faster, leading to unnecessary energy consumption.
Innovation Solution
Incorporation of a freewheel mechanism between the electric motor and the sun gear of the planetary gear train, allowing the sun gear to lock up when the electric motor is switched off, enabling the internal combustion engine to maintain pump speed without the electric motor's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electric motor is continuously operated when the internal combustion engine rotates faster, then the transmission fluid pump is operated at the desired speed, but energy consumption increases
Solution Approach 1:
The system dynamically switches between electric motor drive and internal combustion engine drive based on operating conditions. The freewheel mechanism enables automatic disengagement of the electric motor when the internal combustion engine provides sufficient pump speed, allowing the system to adapt its energy consumption to actual operational needs.
Solution Approach 2:
The freewheel mechanism acts as an intermediary element between the electric motor and the planetary gear train. It allows the electric motor to be decoupled from the pump drive when not needed, while still permitting power transmission when the electric motor is active, thus enabling energy-saving operation without compromising pump performance.
2Use of energy by moving object
If the electric motor is switched off to save energy, then energy consumption is reduced, but the sun gear relative movement causes operational issues
Solution Approach 1:
The freewheel mechanism serves as a mediator that resolves the conflict between energy saving and operational reliability. It allows the electric motor to be switched off without causing harmful relative movements, as the freewheel prevents power transmission from the internal combustion engine to the sun gear when the electric motor is not engaged.
Solution Approach 2:
The freewheel mechanism extracts the problematic relative movement between the sun gear and planet carrier by providing a one-way power transmission path. When the electric motor is off, the freewheel prevents the internal combustion engine from driving the sun gear, effectively removing the source of operational instability.
3Speed
If a planetary gear train is used to couple the internal combustion engine and electric motor to the pump, then the pump can be operated at desired speed, but the system complexity increases
Solution Approach 1:
The planetary gear train serves multiple functions: it couples the internal combustion engine and electric motor to the pump, provides speed multiplication, and enables the freewheel mechanism to function. This multi-functionality reduces the need for separate components and simplifies the overall system architecture despite the inherent complexity of planetary gears.
Data Source
AI summary
A motor vehicle includes a transmission and a transmission fluid pump for transport of transmission oil to and within the transmission. The transmission fluid pump has a moving element which is coupled to a summation shaft of a planetary gear train. The planetary gear train has a ring gear which is operated by a first drive, and a sun gear which is operated by a second drive. A freewheel mechanism is arranged between the sun gear or a shaft connected to the sun gear and a further element so that the second drive can be switched off, when the first drive operates at high speeds while yet maintaining proper operation of the transmission fluid pump.