CONTACTLESS TORQUE SENSOR MODULE

 

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SG2Q TORQUE SENSOR MODULE FOR E-BIKE

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The SG2Q module set is designed as a very responsive contactless torque sensor module. Suitable for a range of applications involving torque measurements on a rotating shaft/spindle using a strain gauge sensor. A prime example application is an e-bike mid-drive motor for higher-end e-bikes where responsiveness and accuracy are key to provide the best rider experience.

By using wireless power and data transfer, the rotating torque shaft side is free of any batteries. A one-millimeter air gap between the rotor part and the stator part provides a friction-free solution. The sensor is ideal for reliable measurement of static and dynamic torque on non-rotating as well as rotating components. Integration into an e-bike system is easy using the optional CAN bus interface or the direct analog torque output.

Zero friction and low power consumption for the fairly high accuracy achieved is the key feature of the technology, along with its compact design and customizable form factor.

High reliability through the use of automotive-qualified components (AEC-Q).

FEATURES

MEASUREMENTS

• Torque range: 0Nm – 500Nm
• Torque resolution: 3500 steps (plus margin)
• Torque accuracy: ±1-2% depending on mechanical design and SG bonding
  (excluding linearity and zero calibration error)
• Torque linearity: ±1% (depending on strain gauge and application)
• Analog torque output latency: 5ms ±1ms [Analog output optional]
• Zero calibration: Selectable at power-on
• Calibration value stored during factory calibration
• Cadence/angular velocity: +/-200 RPM (16/32/64 steps per rotation)

ELECTRICAL

• Power supply: 3.3V – 5.5V DC
• Power consumption: max 50mA

TORQUE/CADENCE OUTPUT

• Serial 0-3V, 19200, N81 output with cadence and torque (10ms sampling interval)
• Option: Analog torque output voltage 0.1 – 2.9V
• Option: CAN 2.0 interface
• Option: Dual quadrature rotational speed outputs

ENVIRONMENTAL

• Operating temperature: -20C to 85C
• Storage temperature: -25C to 95C
• Ingress protection: flexible upon application
• Humidity: 0% – 95% RH, non condensing
• Electromagnetic Compliance: IEC 61000-6-2

RELIABILITY

• Automotive qualified (AEC-Q) components
• IPC-2222 / IPC-2221 and IPC-A-610 Class II conforming PCBA
• 100% contactless with up to 2mm air gap allowing potting, sealing, or coating

Inner diameter (ID) and outer diameter (OD) can be customized on both ROTOR and STATOR. Typical ID values are from 15mm to 100mm. For a radially constrained design, a typical OD is from ID + 15mm.

For an axially constrained design, a typical OD is from ID + 30mm. In the axial direction, the typical minimum size is 4mm plus mechanical fixation (also depending on strain gauge type).

The physical shape and size of the module can be customized for a perfect fit.

For an overview of the different technologies used to make e-bike torque sensors, please see the technology comparison.

APPLICATION EXAMPLES

See examples of various customer application designs in the case studies below:

• Case study 1: E-MTB mid-drive motor with internal gearbox
  For this customer, the mechanical constraint was a more complex 3D bounding box where the sensor had to be integrated.
• Case study 2: E-mobility torque sensor
  This is a good example of a small diameter sensor, where everything had to fit inside a 32mm diameter.
• Case study 3: Super slim wireless torque sensor
  Fitting into a width of only 5.1mm, this customization was made to fit into a very compact automatic electronic gearbox/motor mid-drive unit for maximum convenience e-bikes.

More application examples are available, and we can discuss this – or your customization – under NDA.