Transmission Shift Drum Arrangement for Compact Radial Design

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Solution Overview

Problem

Existing motor vehicle transmission shift drums face challenges with sequential shifting, requiring large radial space and inefficiencies in performing multiple gear shifts within a short time, especially in transmissions with seven or more forward gears.

Innovation Solution

The implementation of a shifting arrangement with multiple shift disks, each assigned to a clutch pack, driven by a single motor, and utilizing a draw key arrangement for axial movement and rotational coupling, allowing non-sequential gear shifts and compact radial design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single shift drum with multiple shifting contours is used, then the device complexity is reduced, but the radial installation space increases

Engineering Contradiction:
Improveshift drum arrangementVSAvoidradial installation space
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

The invention divides a single large shift drum into multiple smaller shift disks (first shift disk, second shift disk, etc.), each handling specific gear shifts. This segmentation reduces the radial space required while maintaining the functionality of multiple shifting contours, as each disk can be independently sized and positioned along the rotational axis rather than requiring concurrent radial space.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If sequential shifting is implemented, then the device complexity is reduced, but the productivity decreases

Engineering Contradiction:
Improveshifting mechanismVSAvoidgear shift speed
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The invention enables pre-selection of gears by allowing the shift drum to be rotated to position the desired shifting contour in advance before the actual shift execution. This preliminary positioning action allows multiple gear shifts to be prepared and executed in rapid succession without sequential delays, significantly improving productivity while maintaining manageable device complexity through the use of a single actuator.

Inventive Principle:
Principle #10Preliminary 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

Enables rapid multiple gear shifts in a compact radial space, reducing wear and increasing efficiency by allowing independent actuation of each clutch pack and minimizing the need for complex coupling mechanisms.

Implementation Method 1

Rotational movements of at least two shift disks (40-1, 40-2) are initiated by a switching motor (50)

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

The actuator assembly (48) has a draw key arrangement (60), which can be moved axially with respect to the at least two shift disks (40-1, 40-2) and/or can be coupled in one direction of rotation with one of the at least two shift disks (40-1, 40-2)

Methodology Applied
Scientific EffectMechanical coupling: Mechanical Force

Data Source

PatentEP3056774B1Shifting assembly for a transmission unit for motor vehicles and shifting method
Publication Date: 2017.12.27 MAGNA PT BV & CO KG
  • EP3056774B1 patent drawingFigure 1~4
  • EP3056774B1 patent drawingFigure 5~6

AI summary

A shift arrangement (30) for a motor vehicle transmission (16) comprising at least two shift clutch packs (32) for engaging and disengaging gear stages (G1, G2, ...), a shift drum arrangement (38) having a shift contour (44) for each shift clutch pack (32) which engages with a driver (42) coupled to the shift clutch pack (32), and an actuator arrangement (48) for driving the shift drum arrangement (38). The shift drum arrangement (38) has at least two shift discs (40), each assigned to a shift clutch pack (32), and the actuator arrangement (48) has a single shift motor (50; 50A) for driving the at least two shift discs (40).