Multi-Speed Adder Assembly for More Gear Ratios in Compact Transmissions

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Solution Overview

Problem

Existing multiple speed transmissions face challenges in achieving a wide range of gear ratios with improved performance, cost efficiency, responsiveness, and packaging constraints, requiring new architectural designs.

Innovation Solution

The design incorporates multiple planetary gearsets with torque-transmitting mechanisms that allow for selective engagement to achieve a variety of forward and reverse speed ratios, including the use of compound planetary gearsets and Ravigneaux gearsets, enabling additional gear ratios without increasing the complexity of existing transmission housings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple planetary gearsets with selective engagement are used, then the number of achievable gear ratios increases, but the device complexity increases

Engineering Contradiction:

Improvenumber of achievable gear ratiosVSAvoidcomplexity of transmission architecture

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple planetary gearsets (first and second planetary gearsets) into a single integrated transmission assembly, where the gearsets share common components such as the reaction member and stationary member. This merging approach enables multiple gear ratios to be achieved through selective engagement of torque-transmitting mechanisms without proportionally increasing overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The second member is designed with a compound structure comprising a first portion and a second portion that are coaxial and rotationally locked together. This compound structure serves multiple functions: it acts as the second member of the first planetary gearset and simultaneously as the carrier of the second planetary gearset. This multi-functionality allows the transmission to achieve multiple gear ratios without adding proportional complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If additional torque-transmitting mechanisms are added to achieve more gear ratios, then the versatility improves, but the manufacturing cost and device complexity increase

Engineering Contradiction:

Improvenumber of forward and reverse speed ratiosVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent uses five torque-transmitting mechanisms (clutches and brakes) that are selectively engaged in combinations of at least two to achieve multiple forward and reverse speed ratios. By merging the functionality of multiple mechanisms into a coordinated system with shared components, the design achieves high versatility without proportionally increasing manufacturing complexity or cost.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The transmission system is segmented into distinct torque-transmitting mechanisms (first through fifth mechanisms) that can be independently controlled. Each mechanism can be selectively engaged or disengaged to achieve different gear ratios, allowing for flexible and cost-effective manufacturing through modular assembly and control.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If compound planetary gearsets are used to achieve additional gear ratios, then the adaptability improves, but the packaging constraints are worsened

Engineering Contradiction:

Improveadditional gear ratiosVSAvoidpackaging volume of transmission

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The first planetary gearset is disposed within a transmission housing and the second planetary gearset is disposed within an add-on housing that is mounted to the transmission housing. The compound planetary gearsets are nested concentrically with shared members, allowing additional gear ratios to be achieved without proportionally increasing the overall packaging volume.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The compound planetary gearsets share common components (reaction member, stationary member, and portions of the second member) between the first and second planetary gearsets. This merging of components reduces the total volume required compared to having separate, non-sharing gearsets, thereby achieving additional gear ratios while respecting packaging constraints.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11933390B2Multi-speed adder assembly in a multi-speed transmission

Publication Date: 2024.03.19 ALLISON TRANSMISSION INC

AI summary

A multiple speed transmission includes an input shaft, an output shaft, a first planetary gearset having a first member, a second member, and a third member, and a second planetary gearset having an input member, a reaction member, a second member, and a third member. The transmission also includes a plurality of interconnecting members each connected between at least one of the first and second planetary gearsets and at least another of the first and second planetary gearsets. The transmission includes a plurality of torque-transmitting mechanisms which are selectively engageable in combinations of at least two to establish a plurality of forward speed ratios and a plurality of reverse speed ratios between the input shaft and the output shaft.