Off-Axis Motor Hybrid Transmission Gear Integration
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Solution Overview
Problem
Conventional hybrid vehicles require a second auxiliary electric motor due to the size constraints of on-axis electric motors, limiting their power output and necessitating costly redesigns to accommodate more powerful motors.
Innovation Solution
An off-axis electric motor is coupled to the transmission via a motor-driven gear and motor drive unit, allowing for sufficient power delivery while minimizing changes to existing engine components, with a torque ratio varying from 5:1 to 8:1, enabling the motor to provide both forward and reverse torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an on-axis electric motor is used in a hybrid vehicle, then the transmission structure is simplified and power transmission efficiency is improved, but the motor size and power output are constrained by existing engine components
Solution Approach 1:
The patent positions the electric motor off-axis relative to the transmission output shaft, changing the spatial arrangement from a conventional on-axis configuration. This dimensional change allows the motor to be located in available space within the engine compartment without being constrained by engine components, thereby enabling a more powerful motor while managing overall system complexity through strategic spatial arrangement.
Solution Approach 2:
The patent introduces a motor-driven gear as an intermediary component between the off-axis electric motor and the transmission output shaft. This intermediary gear, coupled via a motor drive unit, facilitates power transmission from the motor to the transmission while accommodating the off-axis positioning. The motor-driven gear replaces the traditional engine-driven reverse gear and is hard-splined to the output shaft, enabling both forward and reverse torque transmission.
2Power
If a second auxiliary electric motor is added to compensate for insufficient primary motor power, then the required power output is achieved, but the device complexity and cost increase
Solution Approach 1:
By positioning the single electric motor off-axis, the patent enables one motor to provide sufficient power that would otherwise require two motors in a conventional on-axis configuration. The off-axis positioning accesses additional space in the engine compartment, allowing a more powerful motor to be installed without requiring a second auxiliary motor, thereby reducing system complexity while achieving the required power output.
3Device complexity
If the transmission is modified to accommodate an off-axis electric motor, then a single more powerful motor can be used, but changes to existing engine components are required
Solution Approach 1:
The motor-driven gear serves multiple functions: it acts as the transmission interface for the off-axis electric motor, provides both forward and reverse torque transmission, and replaces the traditional engine-driven reverse gear. This multi-functionality reduces the number of separate components needed and simplifies the overall modification process, making the transmission more adaptable to the off-axis motor configuration.
Solution Approach 2:
The motor drive unit and motor-driven gear serve as intermediary components that bridge the off-axis electric motor and the existing transmission system. These intermediaries enable integration with minimal modification to the core transmission structure, as the motor-driven gear replaces only the engine-driven reverse gear while maintaining compatibility with the existing output shaft and transmission architecture.
Data Source
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AI summary
A system and a method for modifying a transmission in a gasoline-electric hybrid vehicle to couple the transmission to an off-axis electric motor. The transmission includes a motor-driven gear that replaces an engine-driven reverse gear. The motor-driven gear is hard-splined to an output shaft of the transmission. An electric motor is coupled to the output shaft of the transmission via the motor-driven gear. The electric motor may thus be oriented along an axis that differs from the axis of the transmission's output shaft.