Asymmetric Locking Disk for Electric Parking Lock Actuator

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Solution Overview

Problem

Existing electric parking lock actuators for motor vehicles are complex and require additional components for emergency operation, leading to increased space and energy requirements, as well as the need for reverse motor operation.

Innovation Solution

A compact electric parking lock actuator design that uses a gear mechanism driven by an electric motor to convert rotational movement into axial movement of an actuating rod, with a locking disk and locking device allowing the actuating rod to move into a locked position using stored energy without electric motor support during emergencies, eliminating the need for reverse operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complex actuating device with multiple freewheels and levers is used for emergency operation, then the parking lock can be actuated without electric motor, but the device complexity increases

Engineering Contradiction:
Improveemergency operation capabilityVSAvoidactuating device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the emergency operation function from the complex multi-component actuating device and integrates it directly into the gear mechanism through the asymmetric locking disk contour. The locking disk's contour is designed to automatically engage with a stop surface in the housing during normal operation, but in emergency mode, the asymmetric design allows the gear mechanism to be manually actuated in reverse without requiring additional freewheels or levers. This extraction and integration eliminates the need for separate emergency actuation components while maintaining the reliability of emergency operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the emergency operation mechanism with the normal operation gear mechanism by using the locking disk's asymmetric contour to serve dual purposes: during normal operation, it engages with the stop surface to prevent reverse rotation, and during emergency operation, the asymmetric design allows manual reverse actuation when the stop surface is overridden. This merging eliminates the need for separate emergency actuation components and simplifies the overall device structure while maintaining both normal and emergency functionality.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If additional components are added for emergency actuation, then emergency operation is enabled, but the space requirements increase

Engineering Contradiction:
Improveemergency actuation capabilityVSAvoidactuator space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The locking disk serves multiple functions: during normal operation, its asymmetric contour engages with the stop surface to prevent reverse rotation of the gear mechanism, and during emergency operation, the same asymmetric contour allows manual reverse actuation when the stop surface is overridden. This multi-functionality eliminates the need for separate emergency actuation components, thereby reducing the space requirements of the actuator while maintaining both normal and emergency operational capabilities.

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

Solution Approach 2:

The invention merges the emergency operation mechanism with the normal operation gear mechanism by using the locking disk's asymmetric contour to serve dual purposes. This integration eliminates the need for additional space-consuming components and reduces the overall actuator size while maintaining both normal and emergency functionality.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the electric motor is designed for bidirectional operation, then normal operation is enabled, but energy consumption and wear increase

Engineering Contradiction:
Improvemotor operation flexibilityVSAvoidmotor energy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The invention uses an asymmetric locking disk contour that is specifically designed to engage with a stop surface in one direction (preventing reverse rotation during normal operation) while allowing manual reverse actuation in emergency mode. This asymmetric design enables the electric motor to operate in a single direction during normal operation, reducing energy consumption and wear, while still permitting emergency reverse actuation through the asymmetric contour's interaction with the stop surface.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The asymmetric locking disk contour acts as an intermediary between the electric motor's unidirectional operation and the bidirectional actuation requirement. During normal operation, the contour engages with the stop surface to enforce unidirectional motor operation, reducing energy consumption. During emergency operation, the contour allows manual reverse actuation by overriding the stop surface engagement, providing the necessary bidirectional capability without requiring the motor itself to be bidirectional.

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 simplifies the actuator design, reduces space and energy requirements, and enables reliable emergency operation without the need for additional components or complex mechanisms, optimizing the electric motor for one-quadrant operation and minimizing wear.

Implementation Method 1

a spring element which prestresses the actuating rod in the direction of the locked position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a gear mechanism which is accommodated in the housing and can be driven in rotation by means of an electric motor and serves to convert a rotational movement into an axial movement of an actuating rod

Methodology Applied
Scientific EffectGear: Gear

Data Source

PatentEP3333463B1Electrical parking lock actuator for a car
Publication Date: 2020.08.19 FTE AUTOMOTIVE GMBH & CO KG
  • EP3333463B1 patent drawingFigure 1
  • EP3333463B1 patent drawingFigure 2
  • EP3333463B1 patent drawingFigure 3~4

AI summary

An electric parking lock actuator (10) has a gear mechanism (34) housed in a casing (32), which can be driven by an electric motor and serves to convert a rotary movement into an axial movement of an actuating rod (38) operatively connected to the gear mechanism and carrying an actuating element (26) for the parking lock. In normal operation, the latter can be moved electrically from an unlocked position to a locked position and vice versa via the gear mechanism and is biased towards the locked position by means of a spring element (40).A locking mechanism (42) serves to hold the actuating rod in its unlocked position against the force of the spring element, which acts as an energy storage device. For this purpose, it has a very compact locking disc (46) connected to the drive mechanism, with a contour (48) that forms a stop surface for a locking device in only one direction of rotation. For emergency operation, the stop surface can be released by the locking device, so that the actuating rod moves into the locked position due to the force of the spring element without electric motor assistance.