Parking Lock Mechanism Yielding to Abnormal Rotational Forces

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Solution Overview

Problem

Existing parking lock mechanisms for vehicle transmissions are prone to damage when subjected to abnormally large rotational forces, such as collisions or excessive inclines, requiring repair.

Innovation Solution

A parking lock mechanism incorporating a motor, actuation shaft, engagement cam, release cam, cam biasing member, pawl member, and lock gear, with a cam biasing member that stores energy to facilitate engagement and disengagement, allowing the mechanism to release under excessive force and prevent damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the parking lock mechanism is designed to be strong and rigid to prevent rolling, then the locking reliability is improved, but the mechanism becomes vulnerable to damage from abnormally large rotational forces

Engineering Contradiction:
Improvelocking reliabilityVSAvoidresistance to abnormal rotational force
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent incorporates a biasing member (spring) that pre-stores energy to create a yieldable connection in the parking lock mechanism. This cushioning element allows the mechanism to absorb and yield to abnormally large rotational forces applied to the output shaft, preventing damage while maintaining normal locking reliability. The biasing member acts as a protective element that sacrifices itself or resets after abnormal events.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the mechanical parameter of rigidity by introducing a yieldable connection through the biasing member. This allows the mechanism to transition from a rigid state during normal operation to a flexible state when abnormal forces are detected, enabling the system to adapt its stiffness based on operational conditions and protect against damage.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the parking lock mechanism uses a simple pawl and gear design, then the device complexity is reduced, but the mechanism lacks protection against abnormal rotational forces

Engineering Contradiction:
Improvemechanism complexityVSAvoidprotection against abnormal forces
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a biasing member as an intermediary element between the pawl assembly and the release cam. This mediator component provides the yieldable connection that protects the mechanism from abnormal rotational forces while maintaining the overall simplicity of the pawl and gear design. The biasing member absorbs the complexity of force management without requiring a complete redesign of the basic locking mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 mechanism effectively prevents damage by releasing when subjected to abnormally large rotational forces, ensuring the parking lock engages securely without sustaining damage, thus enhancing durability and reliability.

Implementation Method 1

a cam biasing member (22) having a first end (46), a coil portion (56) and a second end (54)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2971872B1Parking lock mechanism for a transmission
Publication Date: 2020.12.23 DANA AUTOMOTIVE SYST GRP LLC
  • EP2971872B1 patent drawingFigure 1~2
  • EP2971872B1 patent drawingFigure 3~4
  • EP2971872B1 patent drawingFigure 5

AI summary

A parking lock mechanism having a motor, an actuation shaft, an engagement cam, a release cam, a cam biasing member, a pawl member and a lock gear. The engagement cam has a first side, a second side and a perforation there through. An outer edge of the engagement cam has a contact portion and an engagement portion. The release cam has a first side, a second side and a perforation there through. An outer edge of the release cam has a release member and an engagement portion. The cam biasing member has a first end, a coil portion and a second end. The pawl member has a pivot perforation, an engagement end, a locking protuberance and a sensor protuberance. The pawl member is disposed adjacent the engagement cam and the release cam. The lock gear has a plurality of inner splines and outer teeth.