Rotary Motor Shift Actuator for Automatic Transmission Noise Reduction

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Solution Overview

Problem

Conventional switching devices for automatic transmissions with monostable electric lifting magnets experience increased noise and permanent electrical power loss, leading to annoying actuator noise and elevated energy consumption during gear engagement, particularly when shifting into gear 'D'.

Innovation Solution

The use of a rotary electric motor with detent or holding torque, combined with a toothed rack or worm gear, replaces the monostable electric lifting magnet, reducing noise and eliminating permanent power consumption by only energizing the motor when the end stop is changed or the shift lever is reset.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a monostable electric lifting magnet is used to actuate the end stop, then the shift lever can be automatically reset to the initial position, but continuous electrical power consumption occurs and noise is generated during operation

Engineering Contradiction:
Improveautomatic reset functionVSAvoidcontinuous power consumption
Core Design Contradiction:
Ease of operationVSUse of energy by stationary object

Solution Approach 1:

The patent replaces the continuously powered monostable electric lifting magnet with a bistable mechanism that only consumes energy during state transitions. The rotary electric motor with holding torque energizes the end stop only when gear selection changes are required, eliminating continuous power consumption while maintaining the automatic reset capability through periodic actuation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent substitutes the electric lifting magnet with a rotary electric motor coupled to a rack and pinion or worm gear mechanism. This mechanical substitution allows the system to achieve bistability through mechanical means (holding torque and detent mechanism) rather than continuous electrical power, reducing energy consumption while preserving the automatic reset function.

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

2Ease of operation

If a monostable electric lifting magnet is used to actuate the end stop, then the shift lever can be automatically reset to the initial position, but disturbing actuator noise occurs during gear engagement

Engineering Contradiction:
Improveautomatic reset functionVSAvoidactuator noise
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The rotary electric motor with holding torque operates only during transient periods when gear selection changes are required, rather than continuously. This periodic operation significantly reduces noise generation, as the motor is energized only when the end stop needs to be actuated to enable or block manual shift gate access, eliminating continuous disturbing noise during normal driving.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent replaces the noisy monostable electric lifting magnet with a rotary electric motor system that generates less disturbing noise. The motor's holding torque capability allows it to maintain position without continuous operation, and the detent mechanism provides stable positioning, resulting in quieter operation during gear engagement while maintaining the automatic reset function.

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

3Adaptability or versatility

If the end stop is continuously actuated to allow access to the manual shift gate, then manual gear selection is always available, but electrical power is continuously consumed

Engineering Contradiction:
Improvemanual shift gate accessVSAvoidcontinuous power consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by stationary object

Solution Approach 1:

The patent implements a dynamic end stop actuation system where the rotary electric motor with holding torque adjusts the end stop position based on operational requirements. The end stop is actuated only when manual shift gate access is needed (such as during gear selection changes), rather than remaining continuously actuated, thereby enabling manual gear selection on-demand while eliminating continuous power consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system actuates the end stop periodically only when required for manual gear selection, rather than maintaining continuous actuation. The rotary electric motor with holding torque enables the end stop to be positioned as needed and then holds that position without further power consumption, allowing manual shift gate access when required while significantly reducing overall electrical power consumption during vehicle operation.

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

This solution significantly reduces noise and energy consumption by utilizing a rotary electric motor with holding torque, allowing for bistable or monostable operation of the actuating element, thereby minimizing power loss and enhancing vehicle range in electrically powered vehicles.

Implementation Method 1

a rotary electric motor with detent or holding torque

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

To convert the rotary motion of the electric motor, particularly of a drive gear, into a translational motion of the actuating element, the actuating element can be designed with a rack that is connected to the drive shaft via the drive gear (or alternatively, a worm gear) of the electric motor.

Methodology Applied
Scientific EffectRack and pinion mechanism: Rack and Pinion

Implementation Method 3

To convert the rotary motion of the electric motor, particularly of a drive gear, into a translational motion of the actuating element, the actuating element can be designed with a rack that is connected to the drive shaft via the drive gear (or alternatively, a worm gear) of the electric motor.

Methodology Applied
Scientific EffectWorm drive: Worm Drive

Data Source

PatentEP3191741B1Shifting device for electromechanically actuating an automatic transmission for a vehicle
Publication Date: 2020.09.30 BAYERISCHE MOTOREN WERKE AG
  • EP3191741B1 patent drawingFigure 1~2
  • EP3191741B1 patent drawingFigure 3~4
  • EP3191741B1 patent drawingFigure 5~6

AI summary

The invention relates to a shifting device for electromechanically actuating an automatic transmission for a vehicle, in particular for a motor vehicle or utility vehicle, wherein the shifting device comprises a shift lever that can be moved into different shifting positions, by means of the movement of which shift lever into a particular shifting position the automatic transmission can be actuated in dependence on the particular shifting position, wherein the shifting device also comprises a limiting apparatus that can be actuated by means of an actuator, which limiting apparatus is designed to block or allow a movement of the shift lever from a starting shifting position to a target shifting position in dependence on the actuation by the actuator, wherein the limiting apparatus comprises an actuating element that can be moved in a translational manner along the shift lever and a stop element that can be moved rotationally by means of actuation by the actuating element, wherein the actuating element and the stop element are designed in such a way that, by means of actuation by the actuating element, the stop element is moved rotationally in such a way that the stop element allows the movement of the shift lever from the starting shifting position to the target shifting position. The invention further relates to a vehicle having such a shifting device.