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US-12617490-B2 - Torque sensor system and drive system for an electric bicycle and methods for the use thereof

US12617490B2US 12617490 B2US12617490 B2US 12617490B2US-12617490-B2

Abstract

A torque sensor includes a contact sensor and a contactless sensor. An electric drive system for a bicycle includes an electric motor having a rotor rotatable about an axis. An output component is coupled to the electric motor and is rotatable about an axis. An input component is rotatable about the axis and is concentric with the output component and the rotor. A one-way clutch is disposed between the input component and output component. The contact sensor is coupled to the output component. The contact sensor is configured to measure a torque applied to the output component by the input component and provide an input signal. The contactless sensor is disposed between the output component and a fixed component. The contactless sensor is configured to provide an output signal proportional to the input signal.

Inventors

  • Sage Hahn

Assignees

  • SRAM, LLC

Dates

Publication Date
20260505
Application Date
20231004

Claims (17)

  1. 1 . A torque sensor system for an electric bicycle comprising: an output component rotatable about an axis, wherein the output component is configured to be rotated by an electric motor; an input component rotatable about the axis and concentric with the output component, the input component being a crank axle; a contact sensor coupled to the output component, wherein the contact sensor is configured to measure a torque applied to the output component and provide an input signal; and a contactless sensor disposed between the output component and a fixed component, wherein the contactless sensor is configured to provide an output signal proportional to the input signal.
  2. 2 . The torque sensor system of claim 1 wherein the contact sensor comprises a strain gauge coupled to the output component.
  3. 3 . The torque sensor system of claim 1 wherein the contactless sensor comprises an inner transformer coil and an outer transformer coil spaced apart from and surrounding the inner transformer coil, wherein the inner transformer coil is coupled to the output component and is rotatable about the axis with the output component, and wherein the outer transformer coil is coupled to the fixed component.
  4. 4 . The torque sensor system of claim 1 further comprising a one-way clutch disposed between the input component and output component, wherein the one-way clutch is engaged between the input component and the output component when the input component is rotated in a first rotational direction, and wherein the one-way clutch is disengaged between the input component and the output component when the input component is rotated in a second rotational opposite the first rotational direction.
  5. 5 . The torque sensor of claim 1 wherein the output component comprises a cylindrical portion, wherein the contact sensor is applied to the cylindrical portion.
  6. 6 . The torque sensor of claim 1 wherein the contactless sensor comprises a radio transmitter coupled to the output component and a radio receiver coupled to the fixed component.
  7. 7 . The torque sensor system of claim 1 further comprising a first microprocessor coupled to the output component and rotatable about the axis with the output component, wherein the first microprocessor is operably coupled to the contact sensor, wherein the first microprocessor is configured to receive the input signal and to control a duration of a load current drawn by the contactless sensor.
  8. 8 . The torque sensor system of claim 7 further comprising a second microprocessor operably coupled to the contactless sensor, wherein the second microprocessor is configured to receive the output signal and calculate the torque applied to the output component.
  9. 9 . A torque sensor system for an electric bicycle comprising: an output component rotatable about an axis, wherein the output component is configured to be rotated by an electric motor; an input component rotatable about the axis and concentric with the output component, the input component being a crank axle; and a strain sensor coupled to the output component and rotatable about the axis with the output component.
  10. 10 . The torque sensor of claim 9 further comprising a one-way clutch disposed between the input component and output component, wherein the one-way clutch is engaged between the input component and the output component when the input component is rotated in a first rotational direction, and wherein the one-way clutch is disengaged between the input component and the output component when the input component is rotated in a second rotational opposite the first rotational direction.
  11. 11 . The torque sensor of claim 9 further comprising: a radio transmitter coupled to the output component and rotatable about the axis with the output component; and a radio receiver spaced apart from and in communication with the radio transmitter.
  12. 12 . The torque sensor of claim 9 wherein the output component comprises a cylindrical portion, wherein the strain sensor is applied to the cylindrical portion.
  13. 13 . The torque sensor of claim 12 wherein the strain sensor comprises a first strain gauge having a first orientation and a second strain gauge having a second orientation non-parallel to the first orientation.
  14. 14 . The torque sensor of claim 9 further comprising: an inner transformer coil coupled to the output component and rotatable about the axis with the output component; and a non-rotatable outer transformer coil radially spaced apart from and surrounding the inner transformer coil.
  15. 15 . The torque sensor of claim 14 further comprising a printed circuit board (PCB) coupled to the output component and rotatable about the axis with the output component.
  16. 16 . The torque sensor of claim 15 wherein the PCB is configured as an annular ring.
  17. 17 . The torque sensor of claim 15 further comprising a second microprocessor operably coupled to the outer transformer coil.

Description

BACKGROUND 1. Field of the Disclosure The present disclosure is generally directed to a sensor for a bicycle, and more particularly, to a torque sensor for an electric bicycle, a drive system and methods for the use thereof. 2. Description of Related Art A bicycle with a pedal assist electric motor (e.g., an electric bicycle or an ebike) may include sensors that monitor parameters at the bicycle. The monitored parameters may include, for example, input torque at a crank arm assembly of the bicycle. Sensors that monitor the input torque may be positioned at the rear dropout, with the force from rider applied to the crank set transferred through the chain, cassette, hub, and wheel shaft before the sensor received it, requiring a series of calculations and compensations, and potential error in calculating the torque. Alternatively, the input axle may be directly accessible by the control electronics, so rider torque may be measured directly. In drive system where the motor is concentric to the rider input axle, however, there is no direct path between the control electronics and the rider input shaft, thereby making it difficult to measure the torque at the rider input interface. SUMMARY In one aspect, one embodiment of a torque sensor system for an electric bicycle includes an output component rotatable about an axis, wherein the output component is configured to be rotated by an electric motor. A contact sensor is coupled to the output component. The contact sensor is configured to measure a torque applied to the output component and provide an input signal. A contactless sensor is disposed between the output component and a fixed component. The contactless sensor is configured to provide an output signal proportional to the input signal. In another aspect, one embodiment of a torque sensor system for an electric bicycle includes an output component rotatable about an axis, wherein the output component is configured to be rotated by an electric motor. A strain sensor is operably coupled to the output component and is rotatable with the output component about the axis. In one embodiment, an inner transformer coil is coupled to the output component and is rotatable about the axis with the output component. A non-rotatable outer transformer coil is radially spaced apart from and surrounds the inner transformer coil. In another embodiment, a radio transmitter is coupled to and rotatable with the output component about the axis, while a radio receiver, in communication with the transmitter, is spaced apart from the transmitter and is not in physical contact with the output component. In another aspect, one embodiment of an electric drive system for a bicycle includes an electric motor having rotor rotatable about an axis. An output component is coupled to the electric motor and is rotatable about the axis. An input component is rotatable about the axis and is concentric with the output component and the rotor. A one-way clutch is disposed between the input component and output component. The one-way clutch is engaged between the input component and the output component when the input component is rotated in a first rotational direction, and wherein the one-way clutch is disengaged between the input component and the output component when the input component is rotated in a second rotational opposite the first rotational direction. A contact sensor is coupled to the output component. The contact sensor is configured to measure a torque applied to the output component by the input component and provide an input signal. A contactless sensor is disposed between the output component and a fixed component. The contactless sensor is configured to provide an output signal proportional to the input signal. In one embodiment, the torque sensor includes a first sensor component coupled to the output component and rotatable about the axis with the output component, and a second sensor component radially spaced apart from the first sensor component and coupled to a fixed component, wherein the first and second sensor components are configured to measure a torque applied to the output component. In another aspect, one embodiment of a method of measuring the torque applied to a bicycle drive train includes applying a torque to the output component with an input component, measuring the torque with a contact sensor coupled to the output component, periodically drawing a load current in a contactless sensor based on the measured torque, supplying a supply current to the contactless sensor proportional to the load current, measuring the supply current supplied to the contactless sensor, and calculating the torque based on the measuring of the supply current. The various aspects and embodiments of the torque sensor, drive system and methods provide significant advantages over other torques sensors, drive systems and methods. For example, and without limitation, the torque sensor provides precise torque measurements, and is suitable