Actuator Shift Cam Design for Mode Clutch Positioning
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Solution Overview
Problem
Existing power transfer systems for four-wheel drive vehicles are complex and costly, requiring multiple sensors and actuators to shift between two-wheel drive and four-wheel drive modes, with alignment issues between gears during mode changes.
Innovation Solution
A simplified actuator system using a motor-driven shift cam with a cam follower and Hall effect sensor to control the mode clutch, allowing the mode fork to shift between engaged and disengaged positions based on voltage thresholds, eliminating the need for multiple sensors and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors and actuators are used to control mode shifting, then the reliability of mode detection is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines the functions of multiple sensors into a single Hall effect sensor that detects the position of the mode fork. The shift cam integrates the actuation mechanism with the sensing mechanism, where the cam follower's position on the cam profile surface directly indicates the mode state, eliminating the need for separate sensors for motor position and mode fork position.
Solution Approach 2:
The shift cam serves multiple functions: it actuates the mode fork to shift between two-wheel drive and four-wheel drive modes, and simultaneously provides position information through the cam follower's location on its profile surface. The Hall effect sensor monitors this position to determine the current drive mode, making the system multi-functional with fewer components.
2Adaptability or versatility
If a motor rotates in both directions to control mode shifting, then the adaptability of the actuator is improved, but the device complexity increases
Solution Approach 1:
Instead of using a motor that rotates in both directions to control the mode fork, the patent uses a motor that rotates in only one direction. The shift cam's profile surface is designed with different surfaces (first surface and second surface) that guide the cam follower to different positions, thereby controlling the mode fork to shift between modes through single-direction motor rotation.
3Reliability
If gear alignment is ensured during mode changes, then the reliability of torque transfer is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The shift cam is designed with a ramp surface that gradually guides the mode fork into the engaged position. This preliminary action ensures that the gears are properly aligned before full engagement occurs, reducing the risk of misalignment and improving torque transfer reliability without requiring extremely tight manufacturing tolerances.
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 system effectively and efficiently transfers drive torque between two-wheel and four-wheel drive modes with reduced complexity and cost, ensuring accurate alignment and reliable operation by monitoring output voltage to determine the mode fork's position.
Implementation Method 1
The sensor is a Hall effect transducer. The output of the motor is configured to rotate in a first direction for movement of the mode clutch from the engaged position to the disengaged position
Data Source
AI summary
An actuator that causes a mode clutch to shift between an engaged position and a disengaged position is provided. The actuator comprises a motor having an output. A shift cam is caused to rotate based on the output of the motor. The shift cam has a cam profile surface. A cam follower rides along the cam profile surface upon rotation of the shift cam. Movement of the cam follower causes movement of a mode fork resulting in the mode clutch shifting between the engaged and disengaged positions. A sensor outputs a voltage to a controller based on a physical location of the cam follower. The controller activates the motor based on the voltage.