Gearbox Actuator Position Sensing with Compact Split-Gear Drive

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Solution Overview

Problem

Existing gearbox actuators for vehicle transmissions face challenges in accurately determining the position of gearbox shafts and require large diameter rotating parts for torque, leading to increased size and cost, while existing detection systems are complex and not compact.

Innovation Solution

A mechanical transmission actuator with an electric motor, reduction gear, and a detection system that includes a sensor driving means and printed circuit board to accurately determine the position of the rotor and output shafts, using a compact design that eliminates the need for a hollow rotor shaft and reduces overall size and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If large diameter rotating parts are used to provide required torque for changing between transmission modes, then torque capability is improved, but actuator dimensions increase

Engineering Contradiction:
ImprovetorqueVSAvoidactuator dimensions
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The sensor driving means is nested within the hollow rotor shaft structure, allowing the sensor assembly to be housed inside the rotating component without increasing external dimensions. This enables compact actuator design while maintaining sufficient torque capability through optimized rotor shaft geometry and magnetic coupling mechanisms.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent replaces direct mechanical contact sensors with magnetic field-based sensing through the hollow rotor shaft. This substitution eliminates the need for physical penetration through the rotor shaft while achieving accurate position detection, thereby maintaining compact dimensions without compromising torque transmission capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If complex detection systems are used to determine position of gearbox shafts, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveposition detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection system is extracted from the traditional mechanical sensor approach and repositioned to utilize magnetic field sensing through the hollow rotor shaft. This extraction simplifies the overall system by eliminating complex mechanical linkages and direct contact sensors, achieving position detection through non-contact magnetic field measurement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The hollow rotor shaft serves multiple functions simultaneously: it provides structural support for torque transmission, contains the sensor driving means within its hollow structure, and enables magnetic field-based position detection. This multi-functionality reduces overall system complexity while maintaining measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 provides a more compact and cost-effective gearbox actuator with improved detection accuracy and range, capable of delivering suitable torque for various transmission modes without increasing the actuator's size or cost.

Implementation Method 1

a motor configured to produce a generated torque using electric current applied thereto

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4471299A1Mechanical transmission actuator for a vehicle, detection system for a mechanical transmission and sensor driving means
Publication Date: 2024.12.04 FICO TRIAD
  • EP4471299A1 patent drawingFigure 1~2
  • EP4471299A1 patent drawingFigure 3~4
  • EP4471299A1 patent drawingFigure 5a~6

AI summary

The present mechanical transmission actuator for a vehicle comprises an electric motor (20) configured to rotate a rotor shaft, an output shaft (30) configured to connect to an external shaft, a reduction gear, and a detection system (100). The output shaft is connected to the detection system and further configured to transmit a converted torque from the reduction gear to the external shaft. The detection system is configured to determine a position of the output shaft. The mechanical transmission actuator comprises a sensor driving means, a printed circuit board (PCB), and a first sensor position coupled to the printed circuit board (PCB) and connected to the sensor driving means for sensing a position of the sensor driving means. The sensor driving means comprises a first part (51), a second part (52), and a biasing means (53) configured to push the second part and the first part together. This first part comprises a first gear means (511), and a portion adapted for interacting to a first sensor position, wherein the first gear means is configured to connect to the output shaft. The second part comprises a second gear means (521) configured to connect to the output shaft. In use, the first gear means abuts a first tooth surface of the output shaft and the second gear means abuts a second tooth surface of the output shaft.