Electric Driveline Gear Shift Synchronization

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Solution Overview

Problem

Existing drivelines experience high mechanical wear and operability issues during gear shifts due to the engagement and disengagement of gears and shafts with different speeds and torques, leading to increased maintenance costs and potential mechanical failures.

Innovation Solution

An electric driveline with a hydraulically actuatable synchronizer and an electronic shift controller that manages gear shifts by synchronizing the motor speed with a target speed, limiting torque during disengagement, synchronization, and engagement phases to minimize wear and ensure smooth transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If gears and shafts rotating at different speeds are engaged during gear shift, then gear ratio change is achieved, but mechanical wear increases and operability deteriorates

Engineering Contradiction:

Improvegear ratio changeVSAvoidmechanical wear and operability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The electronic shift controller synchronizes the motor speed with the target speed before the synchronizer engages the gears. This preliminary speed matching prevents direct engagement of gears rotating at different speeds, thereby reducing mechanical wear and avoiding operational disruptions during the gear shift process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The synchronizer acts as an intermediary mechanism between the motor and the output shaft. It facilitates smooth gear transitions by enabling speed synchronization and mediating the engagement process, preventing direct contact between mismatched gear speeds that would cause wear and operational issues.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If traditional mechanical synchronizers are used, then gear shifting is possible, but reliability decreases and maintenance costs increase over long operation periods

Engineering Contradiction:

Improvegear shifting capabilityVSAvoidoperational reliability and maintenance cost

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces traditional mechanically-actuatable synchronizers with a hydraulically actuatable synchronizer. This substitution eliminates the need for complex mechanical actuation mechanisms, resulting in higher reliability over long operation periods and reduced maintenance requirements while preserving full gear shifting capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The synchronizer is actuated through a hydraulic system controlled by the electronic shift controller. Hydraulic actuation provides smooth, precise, and reliable operation without the wear and failure modes associated with mechanical linkages, thereby improving operational reliability and reducing maintenance costs.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Productivity

If gear shift is performed quickly without speed synchronization, then productivity is improved, but mechanical jerks occur and operability deteriorates

Engineering Contradiction:

Improvegear shift speedVSAvoidsmoothness and mechanical stability

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The electronic shift controller continuously monitors the motor speed and compares it with the target speed, adjusting the motor operation in real-time to achieve synchronization before gear engagement. This feedback control enables rapid yet smooth gear shifts, maintaining productivity while eliminating mechanical jerks and ensuring operational stability.

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution reduces mechanical wear and improves driveline operability by ensuring fast and smooth gear shifts, while also being cost-effective in production and maintenance.

Implementation Method 1

a hydraulically actuatable synchronizer (7) for selectively drivingly engaging the electric drive motor (2) with the output shaft (6)

Methodology Applied

Scientific EffectHydraulic actuation: Hydraulic Press

Data Source

PatentUS11242062B2Electric driveline and method of shifting gears

Publication Date: 2022.02.08 DANA ITAL SRL

AI summary

An electric driveline comprising an electric drive motor and a transmission, and a method of shifting gears therefor. The transmission comprises an output shaft, a synchronizer, preferably a hydraulically actuatable synchronizer, for selectively drivingly engaging the electric drive motor with the output shaft via either one of a first gear providing a first gear ratio γ1 between the electric drive motor and the output shaft, and a second gear providing a second gear ratio γ2 between the electric drive motor and the output shaft, and an electronic shift controller for controlling a gear shift from the first gear to the second gear. The electronic shift controller is configured to actuate the synchronizer to disengage the first gear and to engage the second gear, and to synchronize a motor speed of the electric drive motor with a target speed.