Differential Shift Mechanism With Single-Motor Parking Lock
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Solution Overview
Problem
Existing shift devices for vehicles with differentials are often bulky and expensive, lacking a compact and cost-effective solution for simultaneously activating and deactivating both differential and parking lock functions using a single actuator.
Innovation Solution
A shift device with a servomotor actuating a locking sleeve and a locking pawl, allowing for a first shift position to lock the differential, a second shift position to engage the parking lock, and a third neutral position, utilizing a single servomotor to manage both functions efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single servomotor is used to actuate both locking sleeve and locking pawl, then device complexity and manufacturing cost are reduced, but the reliability of simultaneous independent actuation may be compromised
Solution Approach 1:
The single servomotor is segmented into two independent actuation systems through separate drive shafts (first drive shaft for locking sleeve, second drive shaft for locking pawl). This allows one actuator to perform multiple independent functions by dividing its output into separate mechanical pathways, reducing overall device complexity while maintaining independent control capability.
Solution Approach 2:
The servomotor is designed as a universal actuator that can perform both differential lock actuation and parking lock actuation through its two independent drive shafts. This multi-functionality reduces the total number of actuators needed in the system, simplifying the overall device structure and reducing manufacturing costs.
2Ease of manufacture
If a single servomotor with two drive shafts is used, then manufacturing cost is reduced, but the device size may increase due to additional mechanical components
Solution Approach 1:
Two separate actuator systems are merged into a single servomotor assembly with two drive shafts. By combining the housing, control electronics, and power supply into one unit, the overall volume is reduced compared to having two separate actuators, while still achieving the manufacturing cost benefits of using a single actuator platform.
3Reliability
If the locking sleeve is arranged to connect first output shaft to differential carrier in first shift position, then differential lock function is achieved, but the structure becomes more complex
Solution Approach 1:
The differential lock function is extracted as a separate, dedicated mechanism (locking sleeve connecting first output shaft to differential carrier) independent of the parking lock mechanism. This extraction allows each function to be optimized separately while maintaining overall system simplicity through modular design.
Data Source
AI summary
A shift device for a vehicle having a differential for distributing power to a first and second output shafts has a first shift position for locking a differential function, a second shift position for activating a parking lock function, and a third shift position as a neutral position. A servomotor with a drive shaft can displace a first positioning element to actuate a locking sleeve, and displace a second positioning element to actuate a locking pawl. The locking sleeve is rotationally fixed and axially displaceable on the first output shaft and is configured to connect the first output shaft to a differential carrier in a rotationally fixed manner in the first shift position to lock the differential function. The locking pawl can pivot and can engage a gearwheel in the second shift position to fix the differential carrier and activate the parking lock function.