Vehicle Parking Lock With Unidirectional Actuation for Fast Engagement

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Solution Overview

Problem

Existing parking lock systems for electric vehicles often have complex mechanisms with many moving parts, which can lead to slow insert speeds and increased costs due to the need for bidirectional actuator operation.

Innovation Solution

A simplified parking lock design that reduces the number of moving parts by using a blocking wheel and a jack operated via an actuator with a 90° offset wave, featuring a meandering groove that allows for fast insert and release operations with unidirectional actuator drive.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a conventional parking lock mechanism with multiple moving parts is used, then the locking function is reliable, but the insert speed is slow and the device complexity is high

Engineering Contradiction:
Improveinsert speedVSAvoidnumber of moving parts
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into a single integrated actuator mechanism. The actuator performs both the locking and unlocking operations through unidirectional rotation, merging what would traditionally require separate mechanisms into one compact unit. This reduces the number of moving parts while maintaining reliable locking function and achieving faster insert speeds.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuator is designed as a multi-functional component that handles both engagement and disengagement of the parking lock through unidirectional rotation. The meandering groove mechanism enables the same actuator motion to produce both locking and unlocking actions, making the actuator universal for both operations and eliminating the need for bidirectional actuation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If a parking lock requiring bidirectional actuator operation is used, then both locking and unlocking functions are achieved, but the actuator cost and device complexity increase

Engineering Contradiction:
Improveactuator costVSAvoidactuator operation complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

Instead of using bidirectional actuator rotation to achieve locking and unlocking, the patent inverts the approach by using unidirectional actuator rotation. The meandering groove converts the single-direction rotational motion into the necessary reciprocating linear motion for both locking and unlocking operations, simplifying the actuator design and reducing costs.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The meandering groove acts as an intermediary mechanism between the actuator and the parking lock components. It translates the simple unidirectional rotational motion of the actuator into the complex reciprocating motion needed for both engagement and disengagement, eliminating the need for a complex bidirectional actuator while maintaining full functionality.

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 solution achieves significantly faster insert speeds and reduced part costs by minimizing moving parts and allowing the actuator to operate in only one direction, while also ensuring quick unlocking and secure locking mechanisms.

Implementation Method 1

a groove on the circumference of the shaft in which at least one sliding block or roller of a sliding piece is guided, wherein the sliding piece has an anti-twist device and, upon a rotational movement of the shaft, moves in a translational direction parallel to the axis of rotation of the shaft

Methodology Applied
Scientific EffectMechanical motion conversion: Cam

Implementation Method 2

an elastic spring element is provided, which absorbs rotational energy of the drive train when the engagement gear is locked as a result of a relative rotation of the engagement gear and a flange arranged on the drive shaft in a rotationally fixed manner

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

The 90° offset between the shaft and the actuator shaft allows for self-locking of the parking lock proposed according to the invention if the power supply of an electrically driven actuator is interrupted

Methodology Applied
Scientific EffectWorm drive self-locking: Worm Drive

Data Source

PatentEP4211371B1Parking lock for vehicles
Publication Date: 2025.04.23 ROBERT BOSCH GMBH
  • EP4211371B1 patent drawingFigure 1~2
  • EP4211371B1 patent drawingFigure 3~4
  • EP4211371B1 patent drawingFigure 5

AI summary

The invention relates to a parking lock (10) for vehicles, the parking lock (10) comprising a ratchet wheel (12) and a pawl (22) which interacts therewith. The pawl is actuated by means of an actuator (26) via an actuator shaft (28). The actuator (26) is driven in the same direction of rotation when the shaft (22) is actuated, when same adopts a locking position (86) and adopts a release position (94) on the ratchet wheel (12). The invention also relates to the use of the parking lock (10) in an e-axle module of an electrically drive vehicle.