Parking Lock Actuator With Spring Backup and Wide Travel Range

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Solution Overview

Problem

Existing actuators for engaging a parking lock in automatic transmissions require an independent voltage source for emergency mechanisms, which can fail during power outages, leading to unsafe vehicle conditions, and they lack versatility across different transmission variants and manufacturers.

Innovation Solution

An actuator with a drive shaft, first and second actuating elements, and a spring element, featuring a rotary element with control cams and a translation device, allowing for a larger adjustment range to engage and disengage the parking lock across various transmission types, ensuring the spring element is pre-tensioned even in power failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an independent voltage source is used to trigger the emergency mechanism, then the emergency function can be activated, but the system fails when the voltage source is unavailable (e.g., battery discharged)

Engineering Contradiction:
Improveemergency mechanism reliabilityVSAvoidvoltage source requirement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the electrical voltage source with a mechanical spring element as the energy storage device. The spring element is pre-tensioned during normal operation and can mechanically trigger the emergency mechanism without requiring any voltage source, thus eliminating the reliability issue of electrical power failure while maintaining the emergency function.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The spring element serves dual purposes: it stores energy during normal operation and automatically triggers the emergency mechanism when needed, without requiring external intervention or additional power sources. The system uses its own operational movements to pre-tension the spring, making the emergency mechanism self-sufficient.

Inventive Principle:
Principle #25Self-service

2Reliability

If the P stage is left to pre-tension the spring element, then the emergency mechanism is prepared, but the vehicle is left in an unsafe situation with P stage engaged

Engineering Contradiction:
Improveemergency mechanism readinessVSAvoidvehicle safety
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The spring element is pre-tensioned during normal operational movements (when shifting between gears), before any emergency situation occurs. This preliminary action prepares the emergency mechanism without requiring the vehicle to be left in an unsafe state, as the spring is charged during regular use rather than during emergency activation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically tensions the spring element during normal gear shifting operations, allowing the spring to be pre-loaded without leaving the vehicle in a permanent unsafe state. The spring tension is built up and released cyclically during normal operation, maintaining vehicle safety while ensuring emergency readiness.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If a fixed adjustment range is used in the actuator, then the design is simplified, but the actuator cannot accommodate different transmission variants and manufacturers

Engineering Contradiction:
Improvetransmission variant compatibilityVSAvoidadjustment mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The actuator is designed with an adjustable translation device that can accommodate different transmission variants and manufacturers through variable adjustment ranges. The translation device can be configured to provide different movement distances and force characteristics, making the single actuator design universally applicable across multiple transmission types without requiring separate designs for each variant.

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

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

Ensures the parking lock is engaged in all situations, including power failures, and accommodates diverse transmission variants without requiring adjustments, providing a safe and adaptable solution for multiple vehicle manufacturers.

Implementation Method 1

a spring element (5) which can be supported on one side by a housing component (16) of the actuator and on the other side by a second actuating element (17) designed for tensioning the spring element (5)

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP4058694B1Actuator, and device for engaging a parking lock of a motor-vehicle automatic transmission having such an actuator, and motor vehicle equipped therewith
Publication Date: 2026.03.25 KUSTER HLDG GMBH
  • EP4058694B1 patent drawingFigure 1
  • EP4058694B1 patent drawingFigure 2
  • EP4058694B1 patent drawingFigure 3

AI summary

The invention relates to an actuator with a drive which drives a drive shaft, a first actuating element which is operatively connected to the drive shaft, a spring element which can be supported on one side on a housing component of the actuator and is supported on the other side on a second actuating element which is configured for stressing the spring element, wherein a rotational element which can be driven by means of the drive shaft and is rotatably mounted is provided. According to the invention, a further actuating element for actuating a switching device is provided, which further actuating element is operatively connected to the first actuating element, and a transmission device with a transmission element is provided between the first actuating element and the actuating element of the switching device.