Three-Countershaft Auxiliary Section for Heavy Vehicle Transmission Load Distribution

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Solution Overview

Problem

Existing multi-speed double-countershaft vehicular transmissions face limitations in heavy vehicles due to increased cost, reduced reliability, noise, and shorter service life when handling high torque and load, as they require larger axial size and increased gear width.

Innovation Solution

A multi-speed compound vehicular transmission with an auxiliary section featuring three countershafts, where the countershafts are arranged symmetrically around the auxiliary section main shaft, reducing the load on each countershaft and allowing for a thinner gear design, which decreases the axial size and enhances load capacity, noise reduction, and gear life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional single-section transmission is used, then the structure is simple, but the number of speed ratios is limited and cannot meet diverse driving conditions

Engineering Contradiction:

Improvenumber of speed ratiosVSAvoidtransmission structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The transmission is divided into a main section and an auxiliary section, each with independent countershafts and gear sets. The main section provides standard speed ratios while the auxiliary section adds additional ratios, allowing the system to achieve multiple speed ratios without requiring a completely redesigned single-section transmission

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If the auxiliary section uses two countershafts like the main section, then the structure is symmetric and simple, but the number of speed ratios is insufficient

Engineering Contradiction:

Improvenumber of speed ratiosVSAvoidauxiliary section structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The auxiliary section uses three countershafts instead of two, creating an asymmetric configuration that differs from the main section. This asymmetric design allows for additional speed ratios to be generated while maintaining a relatively simple structural arrangement

Inventive Principle:

Principle #4Asymmetry

3Adaptability or versatility

If gear sets are added to increase speed ratios, then more driving conditions can be met, but the transmission size and weight increase

Engineering Contradiction:

Improvedriving condition coverageVSAvoidtransmission size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The auxiliary section with three countershafts is integrated into the existing transmission housing structure, nesting additional gear sets within the available space without requiring a complete redesign of the transmission case, thereby limiting the increase in overall transmission size

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentEP1987979B1Multi-speed compound vehicular transmission having an auxiliary section with three countershafts

Publication Date: 2011.12.28 SHAANXI FAST GEAR CO LTD

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AI summary

A multi-speed compound vehicular transmission having an auxiliary section with three countershafts, including: a main section; and an auxiliary section, wherein the main section includes an input shaft (1), an output shaft (40), a synchronizer (39') and two countershafts (5) symmetrically arranged on both sides of the output shaft (40); the auxiliary section includes an auxiliary section main shaft (25) and a synchronizer (23); wherein a reduction gear (22) is arranged on the main shaft (25), three countershafts (19) are distributed with equal distance around the main shaft (25), and an output end of the main shaft (25) of auxiliary section is connected to a flange (26).