Hybrid Drive Control Device for Speed and Torque Management
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Solution Overview
Problem
Existing vehicle drive devices with hybrid systems face limitations in achieving sufficient driving force at low speeds and efficient fuel consumption at high speeds due to the fixed coupling of the ring gear and second rotating electrical machine, which restricts maximum vehicle speed and degrades torque characteristics.
Innovation Solution
A control device that includes a fixing mechanism to switch between stationary and rotating states of the first rotary element and a decoupling mechanism to switch power transmission between the second rotating electrical machine and the output, allowing for stepless shifting of rotational speed and torque transmission, enabling the vehicle to switch between drive modes based on traveling conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the maximum rotational speed of the second rotating electrical machine is increased to allow higher vehicle speeds, then the maximum vehicle speed is improved, but torque characteristics are degraded and energy losses increase
Solution Approach 1:
The patent applies a decoupling mechanism that dynamically switches between coupled and decoupled states between the second rotating electrical machine and the output member. In the coupled state, the machine operates within its optimal speed range maintaining good torque characteristics. In the decoupled state, the output member can rotate at higher speeds without being constrained by the machine's maximum rotational speed limit, thus resolving the contradiction between achieving high vehicle speeds and maintaining energy efficiency
Solution Approach 2:
The patent changes the operational parameters by introducing a decoupling mechanism that allows the system to transition between different operational modes. When decoupled, the output member's rotational speed is no longer directly limited by the second rotating electrical machine's maximum speed, enabling high-speed travel without the energy losses and torque degradation that would occur if the machine itself had to operate at those speeds
2Speed
If the gear ratio is set to a relatively high fixed value to limit the rotational speed of the second rotating electrical machine, then the maximum vehicle speed is improved, but torque transmitted to the output member at low vehicle speeds is reduced
Solution Approach 1:
The patent uses a dynamically switchable decoupling mechanism that allows the system to adapt between different operational requirements. At low vehicle speeds, the mechanism maintains coupling to ensure adequate torque transmission. At high vehicle speeds, it switches to decoupled mode to allow high-speed operation without being constrained by the machine's rotational speed limit, thus resolving the contradiction between speed and torque
3Device complexity
If the ring gear and the second rotating electrical machine are always coupled to rotate together, then the structure is simplified, but the maximum vehicle speed is limited by the maximum rotational speed of the second rotating electrical machine
Solution Approach 1:
The patent segments the power transmission system by introducing a decoupling mechanism that can separate the second rotating electrical machine from the output member. This segmentation allows the machine to operate independently at lower speeds while the output member can be driven at higher speeds through alternative paths (such as through the differential gear unit and first rotating electrical machine), thus achieving high vehicle speeds without requiring the second machine to operate at prohibitively high speeds
Solution Approach 2:
The patent transforms the static coupled structure into a dynamic system with switchable coupling states. The decoupling mechanism enables the system to transition between coupled and decoupled configurations, allowing flexible adaptation to different speed requirements while maintaining reasonable structural complexity
Data Source
AI summary
A control device that switchably has a first drive mode which is attained with the fixing mechanism being in the non-fixing state and in which a rotational speed of the input is steplessly shifted and transmitted to the output and torque of the second rotating electrical machine is transmitted to the output, and a second drive mode which is attained with the fixing mechanism being in the fixing state and the decoupling mechanism being in the non-transmitting state and in which, with the second rotating electrical machine being decoupled from the output, the rotational speed of the input is shifted according to a gear ratio of the differential gear unit and transmitted to the output.