Meshing Clutch Mechanism for Seamless Two-Speed Torque Reversal
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Solution Overview
Problem
Conventional two-speed transmissions experience torque interruption during gear shifting and fail to transmit torque in the reverse direction at the low-speed stage due to the use of a one-way clutch, which affects smooth gear shifting and energy regenerating in electric vehicles.
Innovation Solution
A meshing clutch mechanism that easily switches between one-way and two-way clutch functions, comprising a rotor with angled tooth faces for positive and negative torque transmission, a sleeve with a cam mechanism to release meshing, and a friction clutch mechanism to adjust torque connection between the sun gear and planet carrier, allowing for torque transmission in both directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-way clutch is used at the low-speed stage to prevent torque interruption, then torque interruption is prevented during gear shifting, but torque in the reverse direction (coasting torque) cannot be transmitted
Solution Approach 1:
The patent employs a meshing clutch mechanism where the clutch state (engaged or disengaged) dynamically changes based on the direction of torque application. The angled tooth faces (120, 123) are designed to automatically engage under positive torque and disengage under negative torque, enabling the system to adapt its behavior to different operating conditions without complex control systems
Solution Approach 2:
The patent changes the geometric parameter of the tooth faces by angling them (120, 123) relative to the radial direction. This angular parameter enables the clutch to differentiate between positive and negative torque directions, allowing automatic engagement/disengagement based on torque direction, thus resolving the contradiction between preventing torque interruption and allowing reverse torque transmission
2Ease of operation
If a friction clutch mechanism is used to adjust torque connection, then smooth torque transmission is achieved, but drag torque loss occurs at the low-speed stage
Solution Approach 1:
The patent extracts the friction element from the low-speed stage meshing clutch mechanism, eliminating the source of drag torque loss. The low-speed stage uses a pure meshing clutch with angled tooth faces that transmit torque through mechanical engagement without friction, thereby removing the energy loss while maintaining smooth operation
Solution Approach 2:
The patent replaces the continuous friction contact mechanism with a meshing clutch that engages and disengages through mechanical tooth interaction. This approach uses short-lived, precise mechanical contact instead of continuous friction, eliminating ongoing energy loss while achieving the desired torque transmission
3Adaptability or versatility
If the meshing clutch mechanism is designed with angled tooth faces to release meshing under negative torque, then reverse torque transmission is enabled, but torque interruption may occur during gear shifting
Solution Approach 1:
The patent incorporates a cam mechanism that performs preliminary action by controlling the timing and sequence of clutch engagement and disengagement. The cam (143, 145) prepares the meshing clutch for direction reversal by gradually reducing engagement force before the actual torque direction change, preventing sudden torque interruption while enabling reverse torque transmission
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
The solution enables seamless gear shifting without torque interruption and allows for reverse torque transmission at the low-speed stage, improving energy regenerating efficiency and reducing drag torque, thus enhancing the overall performance of two-speed transmissions in electric vehicles.
Implementation Method 1
a cam ring being provided with a second cam engaging with the first cam and being configured to convert movement in the rotational direction into movement in the axial direction to be transmitted to the sleeve and lock the meshing
Implementation Method 2
the first meshing clutch having a tooth face to transmit positive torque and a tooth face to transmit negative torque, the tooth face to transmit negative torque angled to release meshing according to the negative torque
Implementation Method 3
a fiction clutch mechanism interposed between the internal gear and the planet carrier to adjust connection between the internal gear and the planet carrier
Data Source
AI summary
A meshing clutch comprises a rotor with a first meshing clutch, a sleeve with a second meshing clutch and a first cam being supported by a clutch hub and urged so as to release meshing, a cam ring configured to convert movement in a rotational direction into movement in an axial direction to lock the meshing according to cooperation of the first and the second cams, and a cam actuator, a sun gear that receives rotation input, an internal gear meshing with the sun gear through a planet pinion, a planet carrier being provided with a drive pinion for output, a fiction clutch mechanism to adjust connection between the internal gear and the planet carrier according to fastening, and a clutch actuator performing fastening control of the friction clutch mechanism.