Gearbox Shift Rod Layout for Post-Mount Assembly and Interlock Control

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Solution Overview

Problem

Current shift control arrangements in gearboxes for vehicles are complex, requiring complete disassembly for repairs and replacements, leading to increased manufacturing and maintenance costs, as well as difficulties in assembly and disassembly, particularly due to the need for precise alignment and assembly sequences that can damage components if improper gear selections are made.

Innovation Solution

A shift control arrangement that allows shift rods to be connected to power means after the main gearbox is mounted, enabling easier assembly and disassembly by using axial cut-outs and lock pins with specific geometries to prevent improper gear shifts, allowing for the disassembly of only the range gearbox device instead of the entire gearbox, and reducing the axial extension and weight of the range gearbox.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If shift rods are rigidly connected to power means before gearbox assembly, then assembly precision is improved, but assembly complexity increases and repairability deteriorates

Engineering Contradiction:
Improveassembly precisionVSAvoidassembly complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The shift control system is divided into separable components: the shift rod assembly can be detached from the power means (such as electric motors). This allows the shift rods to be connected to power means after the main gearbox is mounted, reducing assembly complexity while maintaining precision through controlled connection timing and alignment features.

Inventive Principle:
Principle #1Segmentation

2Ease of repair

If complete gearbox disassembly is required for repairs, then component access is improved, but maintenance time and costs increase

Engineering Contradiction:
Improvecomponent accessVSAvoidmaintenance time
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The gearbox is segmented into modular units that can be independently accessed and repaired. The shift rod assembly can be disconnected from the power means and removed separately, allowing maintenance of shift control components without disassembling the entire gearbox, thus reducing maintenance time and costs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shift rod assembly is extracted as a separable unit from the main gearbox structure. This extraction allows the shift control mechanism to be serviced, repaired, or replaced independently while the main gearbox remains installed, significantly reducing maintenance time and complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If axial displacement of coupling sleeve is used to connect components, then ease of operation is improved, but risk of improper gear selection damage increases

Engineering Contradiction:
Improveshifting operationVSAvoidprotection against improper operation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A control element acts as an intermediary between the shift rod and the coupling sleeve. This control element monitors and regulates the axial displacement of the coupling sleeve, ensuring that connections are only made when proper gear selection conditions are met, thus preventing damage from improper operation while maintaining ease of shifting.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system incorporates feedback mechanisms that monitor the position and state of gear components during shifting operations. This feedback controls the axial displacement of coupling sleeves, preventing connections unless the system is in the correct state, thereby protecting against damage from improper gear selection.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3430289B1Shift control arrangement in a gearbox
Publication Date: 2021.05.12 SCANIA CV AB
  • EP3430289B1 patent drawingFigure 1
  • EP3430289B1 patent drawingFigure 2
  • EP3430289B1 patent drawingFigure 3

AI summary

The invention relates to a shift control arrangement (3) in a gearbox (2), comprising a first shift rod (68), provided with a first and second end part (72, 82), which first end (72) part is connectable to a first power means (66) and the second end part (82) is connected to a first shift fork (60); a second shift rod (70), provided with a first and second end part (73, 84), which first end part (73) is connectable to a second power means (67) and the second end part (84) is connected to a second shift fork (61); a first set of grooves (86) arranged in the first shift rod (68), a second groove (88) ar- ranged in the second shift rod (70); and a lock pin (75) arranged between the first and second shift rod (68, 70), which lock pin (75) together with the first set of grooves (86) and the second groove (88) are arranged to restrict or allow axial movement of the respective first and second shift rod (68, 70). The first end part (72) of the first shift rod (68) is provided with an axial directed cut out (78) for non-conflicting with the lock pin (75), and in that the first end part (73) of the second shift rod (70) is provided with a control surface (80) for axial movement of the lock pin (75). The invention also relates to a gearbox (2) and to vehicle (1), which comprises such a gearbox (2).