Axially Displaceable Intermediate Gear Overlap Against Gear Jump-Out

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Solution Overview

Problem

Existing vehicle transmissions suffer from unintended gear disengagement and bulky designs due to complex manufacturing processes, particularly in heavy-duty vehicles like trucks and construction equipment.

Innovation Solution

A transmission design featuring a sleeve with radially inward intermediate teeth and outward primary and secondary teeth, utilizing overlaps and dual-function secondary intermediate parts to prevent unintended disengagement and reduce bulkiness, allowing for efficient torque transfer and compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional disengagement preventing solutions are used, then gear jump-out is prevented, but the transmission becomes bulky and manufacturing complexity increases

Engineering Contradiction:

Improveprevention of unintended disengagementVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the disengagement prevention function into the secondary intermediate part itself, which is already present for torque transfer. The secondary intermediate part is given a dual function: it transfers torque to the secondary gear and simultaneously prevents disengagement of the intermediate gear through its radial positioning and overlap formation with primary teeth, eliminating the need for separate disengagement prevention mechanisms

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The secondary intermediate part is designed to perform multiple functions: it serves as both the torque transfer element to the secondary gear and the disengagement prevention element through its radial extension and overlap with primary teeth. This multi-functionality reduces the overall number of components and simplifies manufacturing while maintaining reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If traditional disengagement preventing solutions are used, then gear jump-out is prevented, but the transmission length along rotation axis increases

Engineering Contradiction:

Improveprevention of unintended disengagementVSAvoidtransmission length along rotation axis

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The disengagement prevention function is merged into the existing secondary intermediate part structure, which is positioned radially inside the primary intermediate part. This integration allows the transmission to maintain a compact axial length since no additional axial space-consuming components are required

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If complex manufacturing processes are used, then precise gear engagement is achieved, but production cost and complexity increase

Engineering Contradiction:

Improvegear engagement precisionVSAvoidmanufacturing ease

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The gear system is segmented into distinct functional zones: primary teeth and primary intermediate part for one engagement path, and secondary teeth with secondary intermediate part for another path. The secondary intermediate part is radially positioned inside the primary intermediate part, creating clear functional segments that simplify manufacturing while ensuring precise engagement through the overlap design

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The secondary intermediate part acts as an intermediary element that both transfers torque to the secondary gear and prevents disengagement of the intermediate gear. Its radial positioning inside the primary intermediate part and overlap with primary teeth creates a simplified manufacturing approach while maintaining precise gear engagement

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP4382778B1Transmission, gearbox and vehicle

Publication Date: 2026.01.07 VOLVO TRUCK CORP

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AI summary

A transmission (54) comprising a primary gear (56) including primary teeth (70), each having a primary surface (72); a secondary gear (58) including secondary teeth (94); an intermediate gear (60) including intermediate teeth (76), each comprising a primary intermediate part (80) having a primary intermediate surface (88) and a secondary intermediate part (84) having a secondary intermediate surface (92), where the primary intermediate part is axially offset from the secondary intermediate part, and where the intermediate gear is axially displaceable to an engaged position (104) where the primary surface contacts the primary intermediate surface in a contact region (106) and the secondary intermediate surface contacts one of the secondary teeth; wherein in the engaged position, one primary tooth and one intermediate tooth form an overlap (108), radially inside the contact region, for preventing the intermediate gear from being displaced from the engaged position to a disengaged position (102).