Magnetic Sensor Assembly for E-Bike Drive Coupling State Detection

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Solution Overview

Problem

Existing sensor arrangements for vehicles driven by muscle power and engine power, such as electric bicycles, struggle to reliably handle torque peaks and zero-torque conditions, leading to inefficiencies and potential damage in the drivetrain.

Innovation Solution

A sensor arrangement that detects the relative movement and position of coupling elements between the drive shaft and output shaft using magnetic properties, employing a magnetic sensor component decoupled from the coupling module's movement and a magnetically influencing transmitter element, allowing for accurate determination of coupled or decoupled states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If torque sensors are used to detect muscular and machine torques, then force and torque peaks can be avoided to some extent, but cases in the area of zero signal (almost vanishing forces and torques) are difficult to handle

Engineering Contradiction:
Improvehandling of torque peaks and zero-torque conditionsVSAvoiddetection accuracy in zero signal conditions
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

A magnetic coupling module is introduced as an intermediary between the drive shaft and output shaft. This coupling module includes magnetic coupling elements that can be coupled or decoupled without direct mechanical contact, allowing torque transmission while enabling precise detection of coupling states even at zero torque conditions through magnetic field sensing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical coupling with magnetic coupling. Instead of relying solely on mechanical torque sensors that fail at zero signal, the system uses magnetic fields to detect coupling states, substituting mechanical detection with magnetic field-based detection that remains effective at zero torque.

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

2Speed

If the electric drive is suddenly coupled into the output side, then the drive can be activated quickly, but large force and torque peaks occur in the drivetrain

Engineering Contradiction:
Improvecoupling activation speedVSAvoidtorque peaks in drivetrain
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

The magnetic coupling elements are pre-positioned and ready for engagement. Before actual torque transmission begins, the magnetic coupling can be established in advance, allowing the drive to be activated quickly without sudden mechanical shocks or torque peaks in the drivetrain.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The magnetic coupling provides a cushioning effect during engagement. The magnetic field gradually establishes coupling between the drive shaft and output shaft, preventing sudden force peaks that would occur with direct mechanical engagement, thus protecting the drivetrain from shock loads.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If a coupling module is used to couple and decouple the drive shaft and output shaft, then torque peaks can be managed, but the detection of coupled and decoupled states becomes complex

Engineering Contradiction:
Improvetorque peak managementVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The magnetic coupling module serves multiple functions simultaneously: it transmits torque when coupled, allows decoupling to manage torque peaks, and provides detectable magnetic field changes that indicate coupling state. This multi-functionality reduces the need for separate detection systems, simplifying the overall device complexity while maintaining reliable torque peak management.

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

This solution effectively manages torque peaks and zero-torque conditions, ensuring smooth operation and reducing the risk of drivetrain damage by accurately detecting the presence or absence of coupling between the drive shaft and output shaft, thereby enhancing the control and efficiency of hybrid power vehicles.

Implementation Method 1

The sensor arrangement is also set up according to the invention to, with a relative movement and/or a relative position (i) between the first coupling element and a point on the underlying vehicle that is mechanically decoupled from the position and movement of the coupling module or (ii) between the to detect magnetic properties associated with the first and second coupling elements

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP3395664B1Sensor assembly, operation control method for a drive, control device and vehicle
Publication Date: 2020.12.16 ROBERT BOSCH GMBH
  • EP3395664B1 patent drawingFigure 1
  • EP3395664B1 patent drawingFigure 2
  • EP3395664B1 patent drawingFigure 3

AI summary

The present invention relates to a sensor arrangement (50) for the drive (80) of a vehicle powered by muscle power and additionally by motor power, in particular an electric bicycle, e-bike or pedelec, which is configured to detect a relative movement and/or a relative position of a first coupling element (21) and a second coupling element (22) of a coupling module (20) for coupling and decoupling a drive shaft (15) and an output shaft (16) of the drive (80) to each other, with a relative movement and/or a relative position (i) between the first coupling element (21) and a point on the underlying vehicle that is mechanically decoupled from the position and movement of the coupling module (20) or (ii) magnetic properties and/or changes in a path or spatial region between the first and second coupling elements (21, 22) related to the first and second coupling elements (21, 22).to detect between the first and second coupling elements (21, 22), in particular to enable a determination of the presence or absence of a coupled and/or a decoupled state between the first and second coupling elements (21, 22) and thus of the drive shaft (15) and the output shaft (16) of the drive (80).