Sliding Park Pawl Arrangement for Compact Vehicle Locking

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Solution Overview

Problem

Existing park lock arrangements for vehicles are large and heavy, limiting the potential for a more compact and lightweight design that can effectively lock the output shaft without compromising on security and durability.

Innovation Solution

A park lock arrangement where the park pawl slides radially between a release and lock position, utilizing a compact and lightweight design with a return spring, a metal bushing to prevent galvanic corrosion, and an asymmetric actuating means with inclined surfaces to enhance bearing surfaces and ease of operation, allowing for a smaller and more efficient installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional pivoting park pawl with conical bushing is used, then the locking function is reliable, but the device becomes large and heavy

Engineering Contradiction:

Improvelocking functionVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent replaces the traditional pivoting mechanical system with a sliding mechanism. The park pawl body slides along the sliding surface of the actuating means instead of pivoting around a pivot axis, eliminating the need for conical bushings and pivot pins. This substitution reduces the number of mechanical components, decreases device weight, and simplifies the overall structure while maintaining reliable locking functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a planar park pawl body with a thin, extended structure that slides rather than pivots. This flexible sliding design allows the pawl to engage and disengage from the parking gear teeth more efficiently, reducing material usage and overall device weight while preserving the essential locking function.

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If a traditional pivoting park pawl with conical bushing is used, then the locking function is reliable, but the device becomes large

Engineering Contradiction:

Improvelocking functionVSAvoiddevice volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from a three-dimensional pivoting motion to a two-dimensional sliding motion along a planar surface. This dimensional simplification reduces the spatial requirements of the mechanism, allowing for a more compact device volume while maintaining the same locking reliability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If different materials are used for transmission housing and park pawl, then manufacturing flexibility is improved, but galvanic corrosion risk increases

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoidgalvanic corrosion

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a return spring as an intermediary component between the park pawl and the actuating means. This spring mechanism facilitates controlled separation and engagement, reducing direct prolonged contact between dissimilar materials. The return spring acts as a buffer that minimizes galvanic corrosion by limiting the duration and intensity of contact between the park pawl and the transmission housing.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sliding mechanism creates periodic contact between the park pawl and the actuating means, with the return spring ensuring the pawl is regularly separated during the release phase. This periodic separation reduces the cumulative exposure time to galvanic corrosion compared to continuous contact in traditional pivoting systems.

Inventive Principle:

Principle #19Periodic action

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 results in a compact and lightweight park lock arrangement that effectively locks the output shaft, reducing the risk of galvanic corrosion and improving lubrication, while maintaining the ability to withstand forces on slopes, thus enhancing the overall efficiency and reliability of the locking mechanism.

Implementation Method 1

The park lock arrangement comprises a return spring arranged to push the park pawl towards the release position

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

a metal bushing to prevent galvanic corrosion

Methodology Applied

Scientific EffectGalvanic corrosion prevention:

Implementation Method 3

an asymmetric actuating means with inclined surfaces to enhance bearing surfaces and ease of operation

Methodology Applied

Scientific EffectInclined plane: Inclined Plane

Data Source

PatentEP3569456B1Park lock arrangement and vehicle comprising such a park lock arrangement

Publication Date: 2022.08.10 VOLVO CAR CORP

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AI summary

A park lock arrangement for a vehicle, comprising a park pawl, and an actuating means, where the park pawl is arranged to be in either a release position or in a lock position, where the park pawl comprises a body having a lock end and an actuation end, where the park pawl is arranged to slide between the release position and the lock position. The advantage of the invention is that a compact and cost-effective park lock arrangement with is provided.