Electric Vehicle Drive Device With Planetary Gear Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric vehicles with in-wheel motors lack a mechanism for switching between low gear and high gear, which is essential for efficient torque and speed control, leading to inadequate motor operation management.
Innovation Solution
An electric vehicle drive device comprising two motors, a transmission mechanism with planetary gear mechanisms, and a control unit that adjusts motor operation based on gear change information, allowing torque or speed control depending on the gear state, with a one-way clutch to manage gear changes and reduce mechanical shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single motor is used in the in-wheel motor system, then the device complexity is reduced, but the ability to switch between low gear and high gear operations is lost, resulting in inadequate torque and speed control
Solution Approach 1:
The patent divides the motor system into two separate motors (first motor and second motor) instead of using a single motor. This segmentation allows the system to operate in different gear states (low gear and high gear) by controlling each motor independently, thereby achieving gear switching capability while maintaining a relatively simple overall structure
Solution Approach 2:
The two motors are designed to perform different functions depending on the gear state. The first motor primarily provides torque in low gear state, while the second motor takes over for speed control in high gear state. This multi-functionality allows a single motor system to achieve both low gear and high gear operations without requiring complex mechanical gear shifting mechanisms
2Force
If torque control is applied to both motors simultaneously, then the torque output is maximized, but the rotation speed control capability is reduced
Solution Approach 1:
The control system dynamically adjusts the control mode of each motor based on the current gear state. In low gear state, both motors are controlled for torque maximization. In high gear state, the control mode switches to prioritize rotation speed control. This dynamic adaptation allows the system to optimize torque output when needed while maintaining rotation speed control capability when required
3Adaptability or versatility
If mechanical gear shifting mechanism is added to switch between low gear and high gear, then the gear change capability is improved, but the mechanical shock and device complexity increase
Solution Approach 1:
The patent replaces traditional mechanical gear shifting mechanisms with an electrical control system that manages two motors. Gear state transitions are achieved through electronic control signals that adjust motor operations, eliminating the need for mechanical gears, shafts, and synchronizers. This substitution eliminates mechanical shock associated with gear engagement while providing smooth and rapid gear state transitions
Data Source
AI summary
An electric vehicle drive device includes: a first motor; a second motor; a transmission mechanism coupled to the first motor and the second motor; and a control unit configured to control operation of the first motor and the second motor based on a drive signal. The transmission mechanism includes: a sun gear shaft coupled to the first motor; a first planetary gear mechanism; a second planetary gear mechanism; and a one-way clutch configured to restrict a rotation direction of a first carrier to a predetermined positive rotation direction. The drive signal includes gear change information indicating a first state in which the second motor is controlled based on torque or a second state in which the second motor is controlled based on rotation speed, and throttle information indicating an acceleration of rotation speed of a wheel.