Actuator Circuit for Parking Lock Blockage

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Solution Overview

Problem

Existing motor vehicle transmission systems face challenges in actuating parking lock arrangements, particularly in automated transmissions where engaging gears is not always possible, leading to blockages that prevent safe immobilization of the vehicle.

Innovation Solution

A circuit arrangement that allows a single actuator to control both the clutch and parking lock, utilizing a decoupling device with a mechanical energy store, such as a spring, to overcome blockages and ensure safe engagement of the parking lock even when the clutch is blocked, thereby reducing the complexity and cost of the actuator system and ensuring high availability of the parking lock.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single actuator is used to control both clutch and parking lock, then device complexity is reduced, but reliability deteriorates due to potential blockages preventing safe immobilization

Engineering Contradiction:
Improveactuator system complexityVSAvoidparking lock availability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the actuator's movement path into distinct phases: normal operation phase and emergency phase. The decoupling device is positioned to engage only under specific blocked conditions, allowing the actuator to perform both clutch control and parking lock functions while providing a mechanical bypass when blockages occur. This segmentation resolves the contradiction by maintaining simple single-actuator design while ensuring reliability through conditional decoupling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The decoupling device acts as an intermediary mechanical element between the actuator and the clutch/parking lock system. It normally transmits force during regular operation but automatically disengages when blockage is detected, allowing the actuator to directly drive the parking lock. This intermediary mechanism resolves the contradiction by enabling the single actuator to reliably control both functions without direct permanent coupling.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If decoupling device with mechanical energy store is added, then reliability is improved by overcoming blockages, but device complexity increases

Engineering Contradiction:
Improveparking lock availabilityVSAvoidtransmission system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mechanical energy store (spring) is pre-loaded during normal actuator movement before blockage occurs. This preliminary energy storage happens automatically as part of the regular actuation cycle, so that when blockage is encountered, the pre-stored energy immediately becomes available to overcome the blockage and complete the parking lock engagement. This preliminary action resolves the contradiction by preparing the system in advance without adding complex control mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent converts the potential harm of actuator blockage into a beneficial trigger mechanism. When the actuator encounters resistance during normal operation, this resistance automatically compresses the spring in the decoupling device, storing energy that will be released to overcome the blockage. The blockage condition itself becomes the activation signal for the energy release mechanism, resolving the contradiction by transforming a failure mode into a functional feature.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If actuator moves further to engage parking lock when clutch is blocked, then parking lock reliability is improved, but risk of damage increases

Engineering Contradiction:
Improveparking lock engagementVSAvoidmechanical damage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The decoupling device with mechanical energy store acts as a cushioning mechanism that absorbs and manages excessive forces. When the actuator encounters a blocked clutch, the spring compresses to absorb the impact energy, preventing direct transmission of damaging forces to the clutch components. This beforehand cushioning allows the actuator to safely move further to engage the parking lock without causing mechanical damage, resolving the contradiction by protecting components while enabling continued movement.

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

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

This solution provides a robust, low-complexity, and cost-effective method for actuating the parking lock with high availability, meeting safety requirements and allowing normal gear changes while ensuring the parking lock can be engaged even in blocked conditions, thus enhancing vehicle safety and operational reliability.

Implementation Method 1

utilizing a decoupling device with a mechanical energy store, such as a spring

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2733394B1Circuit assembly with parking lock and method for actuating the same
Publication Date: 2020.07.22 MAGNA PT B V & CO KG
  • EP2733394B1 patent drawingFigure 1~1a
  • EP2733394B1 patent drawingFigure 2~3
  • EP2733394B1 patent drawingFigure 4~7

AI summary

A shift arrangement (30) for a motor vehicle transmission (16), comprising: at least one shift clutch arrangement (34) by means of which a gear stage of the clutch transmission (16) can be engaged and disengaged, an actuator arrangement (40) which is coupled to the shift clutch arrangement (34) via a first power transmission device (46), a parking lock arrangement (50) which is coupled to the actuator arrangement (40) via a second power transmission device (56), wherein the actuator arrangement (40) can be moved into a parking lock position (P) in which the parking lock arrangement (50) is actuated, wherein the actuator arrangement (40) is configured to engage the gear stage via the first power transmission device (46) on the way to the parking lock position (P) and/or in the parking lock position (P).The first power transmission device (46) has a decoupling device (58) designed to move the actuator assembly (40) into the parking lock position (P) even when the shift clutch assembly (34) is blocked (Fig. 1).