Wheel-End Gear Synchronization Using Rotational Shutter Control

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Solution Overview

Problem

Traditional power transmission gearsets in wheel-end motors for electric vehicles face a blocked shift condition due to direct tooth-to-tooth contact between shifting and gear teeth at low or zero rotational speed delta, which is exacerbated by the need for mechanical synchronizers that increase cost, complexity, and size.

Innovation Solution

A gear synchronization controller applies a rotational shutter function to the drive gear during zero speed engagement, using frequency, torque, or speed characteristics to create a tapered offset relationship between shifting and gear teeth, preventing blocked shifts without mechanical synchronizers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical synchronizers are added to prevent blocked shift condition, then gear synchronization reliability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvegear synchronization reliabilityVSAvoidmechanical components complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical synchronizer system with an electronic control system. The controller monitors the rotational speed difference between drive and driven gears and controls the actuator to adjust the shifting mechanism timing, eliminating the need for mechanical synchronizing components while achieving the same gear synchronization function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an electronic controller as an intermediary between the gear system components. The controller processes speed difference signals and generates control commands for the actuator, serving as a mediating system that coordinates the shifting operation without requiring direct mechanical synchronization components.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If mechanical synchronizers are added to prevent blocked shift condition, then gear synchronization reliability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvegear synchronization reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive mechanical synchronizer components with electronic control system components (controller, sensor, actuator). This substitution reduces manufacturing costs by eliminating precision-machined mechanical synchronizing parts while maintaining the gear synchronization function through electronic control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If mechanical synchronizers are added to prevent blocked shift condition, then gear synchronization reliability is improved, but packaging space increases

Engineering Contradiction:

Improvegear synchronization reliabilityVSAvoidpackaging space

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces bulky mechanical synchronizer assemblies with compact electronic control components. The controller and actuator occupy significantly less space than traditional mechanical synchronizers, reducing the overall packaging volume while maintaining the gear synchronization function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Ease of operation

If shifting mechanism moves drive gear axially at low speed delta, then gear engagement is achieved, but blocked shift condition occurs due to tooth-to-tooth contact

Engineering Contradiction:

Improvegear engagementVSAvoidshift condition

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent employs feedback control by monitoring the rotational speed difference between drive and driven gears. The controller continuously adjusts the actuator positioning based on the measured speed delta, ensuring optimal timing for the shifting operation and preventing blocked shift conditions through real-time feedback adjustment.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent makes the shifting mechanism dynamically adjustable by controlling the actuator timing based on real-time speed difference measurements. This dynamic adjustment allows the system to adapt the shifting operation to varying operating conditions, preventing blocked shifts while ensuring successful gear engagement.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12060935B2Gear synchronization controller and related method of gear syncronization to prevent a blocked shift condition for a power transferring gear set of a wheel end motor

Publication Date: 2024.08.13 ELECTRIC PROPULSION TECHNOLOGIES LLC

AI summary

A power transferring gearset includes a gear synchronization controller disposed in communication with a drive gear, a driven gear and a shifting mechanism. In response to detecting a gear engagement command, the gear synchronization controller is configured to determine a rotational speed delta between a rotational speed of the drive gear and a rotational speed of the driven gear and compare the rotational speed delta to a pre-determined speed delta. In response to determining that the rotational speed delta is less than the predetermined speed delta, the gear synchronization controller applies a rotational shutter function to the drive gear to apply a series of clockwise and counterclockwise rotational cycles to the drive gear simultaneously during the axial movement of the shifting mechanism for preventing a blocked condition of the power transferring gearset while establishing the meshed relationship between the shifting and gear teeth.