2-Speed Vehicle Transmission With Mechanical Diodes for Seamless Shifting

Solution Overview

Problem

Existing vehicle powertrains with electric motors and planetary drive trains face inefficiencies in shifting gears, particularly in achieving smooth transitions between forward and reverse movements, and require complex clutch mechanisms that interrupt power flow during shifts.

Innovation Solution

A 2-speed transmission system utilizing controllable mechanical diodes (CMDs) with selectable one-way clutches that allow for direct gear engagement and disengagement without power interruption, enabling quick shifts between forward and reverse gears by changing the rotational direction of the electric motor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional clutch mechanisms are used to engage and disengage gears, then gear shifting is achieved, but power flow is interrupted during shifts

Engineering Contradiction:

Improvepower flow continuityVSAvoidclutch mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional friction-based clutch mechanisms with a mechanical diode system that uses one-way clutches and locking elements. This substitution eliminates the need for power interruption during gear shifts, as the mechanical diode allows torque to pass in one direction while blocking it in the opposite direction, enabling seamless gear engagement without the complexity of traditional clutch control systems

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a mechanical diode as an intermediary component between the input shaft and output shaft. This mechanical diode acts as a mediator that selectively transmits or blocks torque based on rotation direction, allowing gear shifts to occur without interrupting power flow. The locking elements and one-way clutches serve as intermediaries that facilitate smooth transitions between gears while maintaining continuous power transmission

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If traditional gear shifting methods are used, then gear changes are achieved, but shifting time exceeds 500 milliseconds

Engineering Contradiction:

Improvegear shifting speedVSAvoidshifting time

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The patent employs preliminary action by pre-positioning locking elements and one-way clutches in readiness before gear shifts are needed. The mechanical diode system is designed so that locking elements can quickly engage or disengage based on rotation direction, eliminating the need for gradual clutch engagement and disengagement. This preliminary preparation enables gear shifts to occur in under 500 milliseconds, significantly reducing shifting time compared to traditional methods

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional friction-based clutch mechanisms with a mechanical diode system that uses one-way clutches and locking elements. This substitution eliminates the need for power interruption during gear shifts, as the mechanical diode allows torque to pass in one direction while blocking it in the opposite direction, enabling seamless gear engagement without the complexity of traditional clutch control systems

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If complex clutch mechanisms are used to control gear engagement, then gear shifting is achieved, but synchronization requirements increase system complexity

Engineering Contradiction:

Improvegear shifting operationVSAvoidsynchronization mechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces traditional friction-based clutch mechanisms with a mechanical diode system that uses one-way clutches and locking elements. This substitution eliminates the need for power interruption during gear shifts, as the mechanical diode allows torque to pass in one direction while blocking it in the opposite direction, enabling seamless gear engagement without the complexity of traditional clutch control systems

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The mechanical diode system operates autonomously based on the direction of torque flow, eliminating the need for complex synchronization control mechanisms. The one-way clutches and locking elements automatically engage or disengage based on rotation direction, making the system self-regulating and significantly simplifying the control architecture compared to traditional clutch-based systems

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12416348B2Vehicle transmission and method of operation

Publication Date: 2025.09.16 MEANS IND INC

AI summary

A vehicle transmission using a gearset. Multi-mode clutches selectively couple components of the gearset. The transmission operates in and shifts between a first forward gear and a second forward gear using a change in input rotation. An electric motor coupled to the input may be used to change the input rotation direction.