Semi-Automatic Transmission Shift Fork Coupling for Fast Assembly

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Automated manual transmissions face challenges in simplifying their switching actuation mechanism to reduce manufacturing costs and assembly complexity, while also preventing tilting moments from being transmitted to actuators during gear changes.

Innovation Solution

The implementation of a longitudinal guide within the transmission housing, where shift forks are accommodated for longitudinal displacement, and actuators have axially displaceable rods with coupling geometries that interact with eccentric coupling arms to transfer linear movements, allowing for quick assembly and disassembly and minimizing tilting moment transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional transmission shift unit with integrated actuators is used, then the structure is compact, but the assembly complexity and manufacturing costs increase

Engineering Contradiction:
Improvemanufacturing costsVSAvoidshifting mechanism complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The transmission shift unit is divided into separate modular components: actuators mounted on the cover and shift forks mounted on the housing. This segmentation allows independent manufacturing and assembly of each component, reducing overall assembly complexity while maintaining compact functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A coupling arm with coupling geometry serves as an intermediary element between the actuator and shift fork. This mediator transmits motion while decoupling the actuator from direct connection to the shift fork, simplifying both components and reducing manufacturing costs.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If shift forks are directly connected to actuators, then the structure is simplified, but tilting moments are transmitted to the actuators during operation

Engineering Contradiction:
Improveshifting mechanism complexityVSAvoidactuator performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The coupling arm acts as a mediator that decouples the actuator from the shift fork, preventing tilting moments from being transmitted to the actuator while maintaining the simplified structure. The coupling geometry allows pure linear motion transmission without moment transfer.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling arm extracts the function of motion transmission from the direct actuator-shift fork connection, separating the actuation function from the shifting function. This protects the actuator from harmful tilting moments while maintaining structural simplicity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If the transmission shift unit is made as a single integrated component, then assembly is robust, but assembly and disassembly time increases

Engineering Contradiction:
Improveassembly robustnessVSAvoidassembly time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The transmission shift unit is segmented into modular components (actuators on cover, shift forks on housing) that can be assembled and disassembled independently. This reduces assembly time while maintaining robust connections through standardized coupling geometries and mounting structures.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3976995B1Semi-automatic transmission
Publication Date: 2024.08.14 ZF CV SYST EURO BV
  • EP3976995B1 patent drawingFigure 1
  • EP3976995B1 patent drawingFigure 2

AI summary

The invention relates to a semi-automatic transmission (114) for a motor vehicle, said transmission comprising a transmission housing (112) which has a detachable cover (10) on which a transmission shifting unit (26) is located, wherein the transmission shifting unit (26) has actuators (30, 32, 34) for actuating shift forks (120, 122, 124) associated with each of said actuators, and wherein in each case an associated sliding sleeve of the semi-automatic transmission (114) can be displaced coaxially with respect to a transmission shaft by means of each shift fork. According to the invention: a longitudinal guide (110) extending parallel to a longitudinal axis (50) of the semi-automatic transmission (114) is fastened in the transmission housing (112); the at least two shift forks are received on the longitudinal guide (110) in a longitudinally displaceable manner; each shift fork has a coupling arm (132, 134, 136) arranged eccentrically with respect to the longitudinal guide (110); each actuator (30, 32, 34) has an axially displaceable actuating rod (40, 42, 44) having a coupling geometry (62, 64, 66); and each coupling arm (132, 134, 136), when the cover (10) and transmission housing (112) are assembled, cooperates with an associated coupling geometry (62, 64, 66) of an associated actuator in such a way that linear movements of the actuating rods (40, 42, 44) of the actuators can be transmitted to the shift forks (120, 122, 124) in order to displace said shift forks on the longitudinal guide (110).