Powershift Transmission Bypass Path for Continuous Power

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Solution Overview

Problem

Conventional transmissions for heavy vehicles experience power interruptions during gear shifts, leading to unfavorable performance, especially in off-road conditions, and are not cost-effective or suitable for future fuel efficiency standards.

Innovation Solution

A dual clutch transmission with a by-passing gearwheel and clutch that allows continuous power transfer during gear shifts, integrated with a planetary range section to eliminate power interruptions and maintain a compact design, while being cost-effective and simple to produce.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional stepped transmission with mechanical tooth clutches is used, then the transmission is robust, compact and cost-effective, but there will be power transfer interruptions during gear shifts

Engineering Contradiction:

ImproverobustnessVSAvoidpower transfer continuity

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The transmission is divided into two independent sub-transmissions (first and second) with separate input shafts, each capable of handling power transfer independently. This segmentation allows one sub-transmission to be shifted while the other maintains continuous power transfer to the output shaft.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A by-pass shaft is introduced as an intermediary power transfer path that connects the input shaft to the output shaft independently of the range section. This by-pass path allows power to flow continuously through alternative routes when the range section is being shifted.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Power

If a planetary gear train with wet multi-plate clutches is used for powershifting, then power transfer continuity is maintained, but the transmission becomes expensive with considerable power losses

Engineering Contradiction:

Improvepower transfer continuityVSAvoidpower losses

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent replaces the planetary gear train with a conventional stepped transmission architecture using gearwheels and tooth clutches. This substitution eliminates the inherent power losses associated with planetary gear operation while maintaining the powershifting capability through dual clutch architecture.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses conventional, cost-effective components such as gearwheels, tooth clutches, and friction clutches that are simpler and cheaper to manufacture than planetary gear trains with wet multi-plate clutches, while achieving the same powershifting function.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Power

If the transmission is designed with two parallel countershafts to enable powershifting, then power transfer continuity is achieved, but the transmission width increases making installation difficult

Engineering Contradiction:

Improvepower transfer continuityVSAvoidtransmission width

Core Design Contradiction:

PowerVSArea of stationary object

Solution Approach 1:

The patent merges the functions of two countershafts into a single shared countershaft that serves both sub-transmissions. This consolidation reduces the transmission width while maintaining the capability for continuous power transfer during shifts.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single countershaft is designed to be universal, serving multiple functions for both the first and second sub-transmissions. It can transmit power from either input shaft and work with gearwheels from both sub-transmissions, eliminating the need for separate countershafts.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Productivity

If a range section is added to double the number of gears for heavy vehicle use, then large reduction ratios are achieved, but power transfer interruptions occur during range section shifts

Engineering Contradiction:

Improvenumber of gearsVSAvoidpower transfer continuity

Core Design Contradiction:

ProductivityVSPower

Solution Approach 1:

The dual clutch architecture allows one sub-transmission to be prepared in advance with the desired gear engaged while the other maintains current power transfer. During range section shifts, the by-pass shaft provides a pre-established alternative power path, ensuring continuity without interruption.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent ensures continuous useful action by providing multiple parallel power transfer paths (through the range section and through the by-pass shaft). When one path is being shifted, the other maintains uninterrupted power flow, ensuring continuous useful action throughout the transmission system.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentEP2510259B1Powershift transmission for a motor vehicle

Publication Date: 2015.12.02 VOLVO TRUCK CORP

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AI summary

Powershift transmission (300) in a motor vehicle, where said powershift transmission is arranged between a prime mover and driven wheels of said motor vehicle for transmission of propulsive power and selection of different gear speed ratios, where said powershift transmission comprising at least two factional clutches (210) for alternatively engaging at least two input shafts (221, 222), a main transmission (220), a range section (360) and an output shaft (371). A countershaft in said powershift transmission is rotationally connectable to said output shaft in order to establish a by-pass torque path (381, 383, 384, 385, 374), passing by said range section, and in which propulsive power can be transferred when said range section is gear shifted between different range speed ratios.