Vehicle Gearbox Control for Tooth-On-Tooth Gear Engagement

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Solution Overview

Problem

Existing gearbox actuators face challenges in resolving tooth-on-tooth situations that prevent full gear engagement, particularly in non-synchronized gearboxes, leading to difficult and precise gear shift operations.

Innovation Solution

A control method and device that utilize a processing circuit to detect tooth-on-tooth situations by analyzing gearbox actuator positions and trigger corrective procedures, including rotational speed pulses and actuator member displacements, to resolve these situations without returning to a neutral position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a non-synchronized gearbox is used to simplify construction, then device complexity is reduced, but gear shift difficulty increases due to tooth-on-tooth situations

Engineering Contradiction:

Improvegearbox constructionVSAvoidgear shift operation

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The control device automatically detects tooth-on-tooth situations using actuator position data and resolves them by triggering rotational speed pulses without driver intervention. The system serves itself by monitoring its own state and autonomously correcting engagement issues, eliminating the need for driver skill to resolve tooth-on-tooth conflicts.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system continuously monitors gearbox actuator position to detect when a tooth-on-tooth situation occurs during gear shifting. This feedback mechanism allows the control device to identify problematic angular positions and trigger corrective rotational speed pulses only when needed, resolving the contradiction between simple construction and easy operation.

Inventive Principle:

Principle #23Feedback

2Reliability

If rotational speed pulses are triggered to resolve tooth-on-tooth situations, then gear engagement reliability is improved, but energy consumption increases

Engineering Contradiction:

Improvegear engagementVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Rotational speed pulses are applied periodically only when tooth-on-tooth situations are detected, rather than continuously. The control device monitors actuator position and triggers pulses selectively during the gear shifting process when engagement problems occur, minimizing energy consumption while ensuring reliable gear engagement when needed.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system changes the rotational speed parameter temporarily in the form of controlled pulses to resolve tooth-on-tooth situations. By adjusting speed only during detected problematic engagement phases and returning to normal operation afterward, the system achieves reliable gear engagement without sustained high energy consumption.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the actuator member is displaced multiple times to resolve tooth-on-tooth situations, then gear shift success rate is improved, but operation time increases

Engineering Contradiction:

Improvegear shift successVSAvoidgear shift time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system replaces repeated mechanical actuator displacements with rotational speed pulses that resolve tooth-on-tooth situations more efficiently. Instead of mechanically pushing the actuator back and forth multiple times, the control device triggers rotational speed pulses that automatically resolve engagement issues, reducing the time required while maintaining high success rates.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The control device detects tooth-on-tooth situations in advance during the gear shifting process and triggers corrective rotational speed pulses before the engagement fails completely. This preliminary intervention prevents multiple failed engagement attempts, reducing overall gear shift time while ensuring success.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250314295A1Control method and control device for a vehicle gearbox

Publication Date: 2025.10.09 ZF CV SYST EURO BV

AI summary

A device and method to detect and resolve a tooth-on-tooth situation of a gearbox (40) are provided. The device (20) includes at least one processing circuit (30) configured to obtain a gearbox actuator position (16) indicative of a position of an actuator member (52, 53) of a gearbox actuator (50). The at least one processing circuit (30) is configured to process the gearbox actuator position (62) to detect a tooth-on-tooth situation and to trigger a corrective procedure to resolve the tooth-on-tooth situation. The corrective procedure includes triggering, by the at least one processing circuit (30), a rotational speed pulse (67, 68) or several rotational speed pulses (67, 68) for an input shaft (45) of the gearbox (40) to resolve the tooth-on-tooth situation.