Parking Lock Torque Release Mechanism for Vehicle Shift Load Reduction
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Solution Overview
Problem
Existing parking lock devices for vehicles engage the parking gear and locking lug during vehicle travel, leading to increased frictional force and load when shifting, especially when torque remains in the rotating member, causing operational difficulties and potential wear.
Innovation Solution
A parking lock device with a parking gear and locking pawl mechanism that includes a pre-compressed elastic body in a space between the parking lock gear and base, which expands and contracts to release torque, reducing the load on the locking lug and preventing torque transfer from the parking gear to the locking pawl.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the parking gear and locking lug are engaged during vehicle travel when torque remains in the rotating member, then the parking lock device can stop rotation of the rotating member, but the frictional force between the parking gear and cam mechanism increases, resulting in increased load on the shift lever
Solution Approach 1:
A torque release mechanism is introduced as an intermediary between the parking gear and the locking pawl. This mechanism includes a torque release member with a pressing portion that can press against the locking pawl, and a torque release spring that provides the pressing force. When torque remains in the rotating member during parking lock engagement, the torque release mechanism automatically activates to release this torque, preventing it from being transmitted to the locking pawl and cam mechanism, thereby reducing frictional force and operational load while maintaining reliable parking lock function
2Reliability
If the parking gear and locking lug are engaged when torque remains in the rotating member, then the parking lock device can be activated, but torsional torque is applied from the parking gear to the locking pawl, increasing wear and load
Solution Approach 1:
The torque release mechanism serves as a protective intermediary that intercepts torsional torque before it can damage the locking pawl and cam mechanism. The torque release member, actuated by the torque release spring, automatically engages to release remaining torque in the rotating member during parking lock activation, thereby eliminating the harmful torsional stress that would otherwise cause increased wear and operational load
3Device complexity
If a simple engagement mechanism is used between parking gear and locking pawl, then the device complexity is reduced, but torque release function is not provided, leading to increased load during shifting
Solution Approach 1:
A torque release mechanism is introduced as an intermediary component between the parking gear and locking pawl. This mechanism includes a torque release member with a pressing portion, a torque release spring, and a pressing surface on the locking pawl. The mechanism adds moderate structural complexity but provides essential torque release functionality that significantly reduces shifting operation load by preventing torque transmission to the locking mechanism during engagement
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 effectively releases remaining torque in the rotating member, reducing the load on the shift lever and minimizing wear, while maintaining a compact design and using inexpensive components.
Implementation Method 1
An elastic body is provided in the space in a pre-compressed state. When the parking lock device is placed in the locked state in a condition where torque remains in the rotating member, the elastic body provided in the space expands and contracts in accordance with relative rotation of the parking lock gear and the parking lock gear base, so that torque that remains in the rotating member is released
Data Source
AI summary
A parking lock device for a vehicle includes a parking gear, a locking pawl, and a cam mechanism. The parking gear includes a parking lock gear that includes outer teeth that engage with a locking lug and rotates about a rotation axis, and a parking lock gear base fixed to an output shaft and allowed to rotate relative to the parking lock gear about the rotation axis. A space is provided between the parking lock gear and the parking lock gear base, such that the space expands and contracts in a circumferential direction according to relative rotation of the parking lock gear and the parking lock gear base, and an elastic body is provided in the space in a pre-compressed state.