Sensor Assembly for E-Bike Drive Coupling State Detection

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Solution Overview

Problem

Existing sensor arrangements for vehicles that can be driven with muscle power and engine power, such as electric bicycles, often fail to reliably handle cases where muscle torque applied is almost zero, leading to difficulties in managing force and torque peaks, particularly when transitioning from muscle power to motor assistance.

Innovation Solution

A sensor arrangement that detects the relative movement and position of coupling elements between the drive shaft and output shaft using acoustic, optical, or magnetic measurement principles, allowing for precise determination of coupled or decoupled states, thereby enabling controlled engagement and disengagement of the motor assistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If torque sensors are used to measure muscular and machine-generated torques, then force and torque peaks can be prevented, but cases with zero signal where applied forces and torques are almost negligible cannot be reliably managed

Engineering Contradiction:
Improvereliability in detecting torque peaksVSAvoidmeasurement precision in zero-torque conditions
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The coupling state detection is segmented into distinct states (coupled vs. decoupled) using multiple sensor components. The system divides the detection task into: (1) torque measurement for normal operation, and (2) coupling state detection for transition management, allowing each to be optimized independently for their respective measurement ranges

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor arrangement combines multiple sensor components (acoustic, optical, magnetic) that can serve different functions. The same sensor system detects both torque magnitude and coupling state, providing universal detection capability across the full range of operating conditions including zero-torque scenarios

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

2Speed

If the electric drive engages abruptly on the output side, then motor assistance can be quickly provided, but large peaks in force and torque occur in the drivetrain

Engineering Contradiction:
Improveengagement speed of electric driveVSAvoidforce peaks in drivetrain
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

The system performs preliminary detection of the coupling state before motor engagement. By detecting whether the coupling elements are already coupled or still decoupled, the control system can prepare the motor engagement in advance, initiating torque application only after coupling is confirmed, thereby preventing sudden force peaks

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sensor arrangement provides continuous feedback on the coupling state to the control system. This feedback loop allows the control system to monitor coupling progression and adjust motor engagement timing and torque application rate accordingly, smoothing the transition and preventing abrupt force peaks

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

This solution effectively manages torque peaks and zero-torque conditions, ensuring smooth transitions between muscle power and motor assistance, enhancing the reliability and efficiency of electric bicycle drives.

Implementation Method 1

The sensor arrangement according to the invention is designed to detect sound, noise, mechanical vibrations, inertial forces and/or their effects associated with a relative movement and/or a relative position of the first and/or the second coupling element

Methodology Applied
Scientific EffectAcoustic emission: Acoustic Emission

Implementation Method 2

the sensor arrangement according to the invention can be configured to detect optical properties and/or changes in a light path between the first coupling module and the location on the underlying vehicle or between the first and second coupling elements

Methodology Applied
Scientific EffectLight path detection: Reflection

Implementation Method 3

the sensor arrangement according to the invention is designed to detect magnetic properties and/or changes in a path or spatial area between the first coupling module and the location on the underlying vehicle or between the first and second coupling elements

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP3395666B1Sensor assembly, operation control method for a drive, control device and vehicle
Publication Date: 2020.11.25 ROBERT BOSCH GMBH
  • EP3395666B1 patent drawingFigure 1
  • EP3395666B1 patent drawingFigure 2
  • EP3395666B1 patent drawingFigure 3

AI summary

The present invention relates to a sensor arrangement (50) for the drive (80) of a vehicle that can be propelled by muscle power and additionally by motor power, in particular an electric bicycle, eBike 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, in particular to thereby 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 (60) of the drive (80).