Torsion detection device and torsion detection assembly

Abstract

A torsion detection assembly comprises a shaft rod and a torsion detection device. The torsion detection device comprises at least one conducting ring and an internal device, and the conducting ring is arranged on the shaft rod and receives first electric power in a sliding contact mode; the internal device is arranged on the shaft rod and comprises a torsion sensing module, an internal voltage adjusting circuit and an internal control module, and the torsion sensing module senses the torsion of the shaft rod and generates a corresponding electric signal; the internal control module judges the torsion sensed by the torsion sensing module according to the electric signal, and controls the internal voltage adjusting circuit to change the voltage on the conducting ring according to the torsion sensed by the torsion sensing module so as to form a first variable voltage signal. By externally measuring the voltage variation of the conducting ring, a first variation voltage signal corresponding to the torsion can be obtained.

Description

Technical Field

[0001] The present invention relates to torque detection of a shaft, and in particular to a torque detection device and a torque detection assembly. Background Art

[0002] Many devices use rotating shafts, such as power tools, impact tools, bicycles, processing machines, etc. Since the rotating shaft rotates continuously, when the torque on the rotating shaft needs to be measured, an indirect torque detection device is usually used to couple with the rotating shaft to indirectly measure the torque on the rotating shaft. Since the torque of the rotating shaft is measured indirectly, it is impossible to provide accurate torque measurement results.

[0003] In order to accurately measure the torque on the shaft, the known technology is to install a torque sensor on the shaft, and then transmit the torque measured by the torque sensor to an external system via a wireless transmission device in the form of a wireless signal. However, the cost of the wireless transmission device is relatively high. In some environments, the wireless signal may be affected by other devices or electromagnetic interference, resulting in unstable or interrupted communication.

[0004] Therefore, the existing torque measurement method of the rotating shaft is still not perfect and needs to be improved. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a torque detection device and a torque detection assembly, which can directly sense the torque of the shaft and convert the sensed torque into a corresponding variable voltage signal.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a torque detection device for detecting the torque of a shaft; the torque detection device includes at least one conductive ring and an internal device; wherein the at least one conductive ring is arranged on the shaft, and the at least one conductive ring receives a first power in a sliding contact manner; the internal device is arranged on the shaft and includes a torque sensing module, an internal voltage adjustment circuit and an internal control module, wherein the torque sensing module senses the torque of the shaft and generates a corresponding electrical signal; the internal voltage adjustment circuit is electrically connected to the at least one conductive ring, and .... The circuit can be controlled to change the voltage of the first power on the at least one conductive ring; the internal control module is electrically connected to the torque sensing module and the internal voltage adjustment circuit, the internal control module determines the torque sensed by the torque sensing module based on the electrical signal, and the internal control module controls the internal voltage adjustment circuit to change the voltage of the first power on the at least one conductive ring to form a first variable voltage signal based on the torque sensed by the torque sensing module, wherein the first variable voltage signal varies between a first voltage and a second voltage, and the second voltage is less than the first voltage.

[0007] A torque detection assembly provided by the present invention comprises a shaft and a torque detection device; wherein the torque detection device comprises at least one conductive ring and an internal device, wherein the at least one conductive ring is arranged on the shaft, and the at least one conductive ring receives a first power in a sliding contact manner; the internal device is arranged on the shaft and comprises a torque sensing module, an internal voltage adjustment circuit and an internal control module, wherein the torque sensing module senses the torque of the shaft and generates a corresponding electrical signal; the internal voltage adjustment circuit is electrically connected to the at least one conductive ring, and the internal voltage adjustment circuit is electrically connected to the at least one conductive ring. The circuit can be controlled to change the voltage of the first power on the at least one conductive ring; the internal control module is electrically connected to the torque sensing module and the internal voltage adjustment circuit, the internal control module determines the torque sensed by the torque sensing module according to the electrical signal, and the internal control module controls the internal voltage adjustment circuit to change the voltage of the first power on the at least one conductive ring to form a first variable voltage signal according to the torque sensed by the torque sensing module, wherein the first variable voltage signal varies between a first voltage and a second voltage, and the second voltage is less than the first voltage.

[0008] The effect of the present invention is that the internal control module can control the internal voltage adjustment circuit according to the torque sensed by the torque sensing module to change the voltage on the conductive ring to form a first variable voltage signal corresponding to the torque. By measuring the voltage change of the conductive ring externally, the first variable voltage signal corresponding to the torque can be obtained, so as to further analyze the first variable voltage signal to obtain the torque sensed by the torque sensing module. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 FIG. 4 is a schematic diagram of a torque detection assembly according to a first preferred embodiment of the present invention.

[0010] Figure 2 FIG. 4 is a circuit diagram of a torque detection device according to a first preferred embodiment of the present invention.

[0011] Figure 3 Schematic diagram of voltage waveform of the first preferred embodiment of the present invention.

[0012] Figure 4 FIG. 4 is a circuit diagram of a torque detection device according to a second preferred embodiment of the present invention.

[0013] Figure 5 FIG. 4 is a circuit diagram of a torque detection device according to a third preferred embodiment of the present invention.

[0014] Figure 6 Schematic diagram of a torque detection assembly according to a fourth preferred embodiment of the present invention.

[0015] Description of reference numerals:

[0016] 100, 200: Torque detection assembly

[0017] 10: Axle

[0018] 102: Grooving

[0019] 12: Torque detection device

[0020] 14, 142, 144: Conductive ring

[0021] 16: Internal Devices

[0022] 18: Torque sensing module

[0023] 20: Strain gauge

[0024] 22: Readout circuit

[0025] 222: Differential Circuit

[0026] 224: Amplifier circuit

[0027] 24: Internal voltage regulation circuit

[0028] 26: Internal control module

[0029] 27: Circuit Board

[0030] 28: Power conversion module

[0031] 282: Power output terminal

[0032] 30: Insulation sleeve

[0033] 32, 322, 324: Conductive parts

[0034] 34: External devices

[0035] 36: Power supply module

[0036] 38: Power supply

[0037] 40: Power conversion module

[0038] 402: Power output terminal

[0039] 42: External control module

[0040] 44: Comparator circuit

[0041] 46: Power conversion module

[0042] 48: Torque detection device

[0043] 50: External voltage adjustment circuit

[0044] 52: Voltage divider circuit

[0045] 54: Torque detection device

[0046] 56: Internal voltage regulation circuit

[0047] 58: Sensor

[0048] 60: Voltage divider circuit

[0049] 62: External voltage adjustment circuit

[0050] 64: Bearings

[0051] 66: Shell

[0052] Hi: High level voltage

[0053] Low: Low level voltage

[0054] V1: first voltage

[0055] V2: Second voltage

[0056] Vref: reference voltage

[0057] S1, S2: Switching elements

[0058] T: Period

[0059] ZD1~ZD4:Zener diode DETAILED DESCRIPTION

[0060] In order to more clearly illustrate the present invention, preferred embodiments are described in detail below with reference to the accompanying drawings. Figure 1 and Figure 2 FIG. 1 shows a torque detection assembly 100 according to a first preferred embodiment of the present invention, which includes a shaft 10 and a torque detection device 12 of the present embodiment.

[0061] The shaft 10 in this embodiment is a rotatable shaft, such as a drive shaft of an electric tool, a bottom bracket (BB) of a bicycle, a drive shaft of an impact tool, a main shaft of a processing machine, etc. The shaft 10 in this embodiment is made of metal, but not limited to this. The shaft 10 has two grooves 102, and the two grooves 102 are located at opposite positions in the radial direction of the shaft 10.

[0062] The torque detection device 12 is used to detect the torque generated by the shaft 10 and output a variable voltage signal (ie, a first variable voltage signal) corresponding to the torque.

[0063] The torque detection device 12 includes at least one conductive ring 14 and an internal device 16. The at least one conductive ring 14 is disposed on the shaft 10, and the at least one conductive ring 14 receives a first power in a sliding contact manner. The first power has a first voltage under normal conditions. The first voltage is, for example, 10V, but is not limited thereto, and can also be a voltage between 10 and 15V. In this embodiment, the at least one conductive ring 14 is a metal ring, such as a copper ring. The number of the at least one conductive ring 14 is two, and the two conductive rings 142 and 144 are sleeved on the shaft 10 and surround the outer circumference of the shaft 10. In the axial direction of the shaft, the two grooves are located between the two conductive rings. An insulating sleeve 30 is disposed between each of the conductive rings 142 and 144 and the shaft 10, and the insulating sleeve 30 is located between the conductive rings 142 and 144 and the outer circumference of the shaft 10 to electrically isolate each of the conductive rings 142 and 144 from each of the shafts 10. When the shaft 10 rotates, the two conductive rings 142 and 144 rotate along with the shaft 10. The two conductive rings 142 and 144 receive the first power in a sliding contact manner, wherein one conductive ring 142 is positively charged and the other conductive ring 144 is grounded. In one embodiment, there can also be one conductive ring 142, the conductive ring 142 is positively charged, and the shaft 10 made of metal material can be used as a ground.

[0064] The internal device 16 is disposed on the shaft 10 and rotates with the shaft 10. The internal device 16 includes a torque sensing module 18, an internal voltage adjustment circuit 24, and an internal control module 26. The torque sensing module 18 is disposed on the shaft 10. The torque sensing module 18 senses the torque of the shaft 10 and generates a corresponding electrical signal. The torque sensing module 18 includes at least one strain gauge 20. The at least one strain gauge 20 is used to sense the torque of the shaft 10 along at least one rotation direction. The torque sensing module 18 also includes a readout circuit 22, which is used to convert the sensing signal of the at least one strain gauge 20 into the electrical signal. In this embodiment, two strain gauges 20 are used. The two strain gauges 20 are respectively fixed in the two slots 102 of the shaft 10 to sense the torque of the shaft 10 along two opposite rotation directions. The internal device 16 also includes a circuit board 27. The circuit board is disposed on the shaft 10 and located between the two slots 102. The readout circuit 22 is disposed on the circuit board 27. The readout circuit 22 includes a differential circuit 222, two input terminals of the differential circuit 222 are electrically connected to the two strain gauges 20, and an output terminal of the differential circuit 222 outputs the simulated electrical signal. Optionally, the readout circuit 22 may include an amplifier circuit 224, which amplifies the voltage output by the differential circuit 222 to form the electrical signal.

[0065] For example, when the shaft 10 does not generate torque (i.e., 0 N-m), the voltage of the electrical signal is 2.5 V. When the shaft 10 generates torque in a forward direction, the voltage of the electrical signal increases from 2.5 V, and the voltage increases as the torque increases. The upper limit of the voltage may be, for example, 5 V. Conversely, when the shaft 10 generates torque in a reverse direction, the voltage of the electrical signal decreases from 2.5 V, and the voltage decreases as the torque increases. The lower limit of the voltage may be, for example, 0 V. Alternatively, when the shaft 10 does not generate torque, the voltage of the electrical signal is 1.65 V, the upper limit of the voltage may be, for example, 3.3 V, and the lower limit of the voltage may be, for example, 0 V.

[0066] The internal voltage adjustment circuit 24 and the internal control module 26 are disposed on the circuit board 27. The internal voltage adjustment circuit 24 is electrically connected to the at least one conductive ring 142, and the internal voltage adjustment circuit 24 can be controlled to change the voltage of the first power on the at least one conductive ring 142. The internal voltage adjustment circuit 24 includes a Zener diode ZD1 and a switch element S1 connected in series, and the Zener diode ZD1 and the switch element S1 are sequentially connected in series between the two conductive rings 142 and 144. The cathode of the Zener diode ZD1 is connected to one of the conductive rings 142, the anode of the Zener diode ZD1 is connected to a first end of the switch element S1, a second end of the switch element S1 is electrically connected to the other conductive ring 144, and a third end of the switch element S1 is controlled to turn on or off the first end and the second end. In this embodiment, the switch element S1 is a BJT, but is not limited thereto, and can also be a MOSFET. When the switch element S1 is turned off, the first power has the first voltage, that is, the voltage across the two conductive rings 142 and 144 is maintained at the first voltage; when the switch element S1 is turned on, the Zener diode ZD1 collapses in reverse, so that the first power has a second voltage, that is, the voltage across the two conductive rings 142 and 144 is the second voltage, and the second voltage is the collapse voltage of the Zener diode ZD1. The second voltage is less than the first voltage, for example, the second voltage is 7V, but not limited thereto.

[0067] The internal control module 26 is electrically connected to the torque sensing module 18 and the internal voltage adjustment circuit 24. In this embodiment, the internal control module 26 may be, for example, a microcontroller, and the internal control module 26 is electrically connected to the readout circuit 22 of the torque sensing module 18 and the third end of the switch element S1 of the internal voltage adjustment circuit 24. The internal control module 26 may have a built-in analog / digital converter to convert the analog electrical signal into a corresponding digital value. The internal control module 26 determines the torque sensed by the torque sensing module 18 based on the electrical signal, and the internal control module 26 controls the internal voltage adjustment circuit 24 to change the voltage of the first electrical power on the at least one conductive ring 142 to form a first variable voltage signal based on the torque sensed by the torque sensing module 18, and the voltage of the first variable voltage signal varies between the first voltage and the second voltage. In other words, the first variable voltage signal corresponds to the torque sensed by the torque sensing module 18.

[0068] In this embodiment, the first variable voltage signal is a pulse width modulation signal, and the internal control module 26 outputs a corresponding control signal to the switch element S1 according to the torque value to generate the first variable voltage signal. The control signal is also a pulse width modulation signal. Preferably, the frequency of the control signal and the first variable voltage signal is a predetermined frequency, and the predetermined frequency is between 200 and 300 Hz. In this embodiment, it is 250 Hz, that is, the period of the control signal and the first variable voltage signal is 4 ms. The purpose of setting the predetermined frequency is to enable the first variable voltage signal to be distinguished from the unexpected variable voltage generated during the bounce when a bounce occurs between the conductive members 322, 324 and the conductive rings 142, 144.

[0069] For example, Figure 3As shown, the period T of the control signal and the first variable voltage signal is 4ms as an example. The control signal uses the high voltage Hi to represent the value of the torque to be transmitted, and the pulse width of the high voltage Hi represents the value of the torque. For example, a duty cycle of 50% represents 0N-m. When the shaft 10 rotates forward to generate a torque, the duty cycle increases from 50% to a first predetermined duty cycle, and when the shaft 10 rotates backward to generate a torque, the duty cycle decreases from 50% to a second predetermined duty cycle. The duty cycle represents the value of the torque by modulating. In contrast, the first variable voltage signal corresponds to the control signal, and the width of the first variable voltage signal at the second voltage V2 corresponds to the width of the pulse of the high voltage Hi of the control signal. In other words, the first variable voltage signal is a pulse width modulation signal opposite to the control signal. By detecting the ratio of the width of the second voltage V2 to the entire period T, which is equivalent to the duty cycle of the control signal, the voltage waveform between the two conductive rings 142 and 144 can be measured externally, and the torque sensed by the torque sensing module can be determined using the first variable voltage signal. In one embodiment, the ratio of the width of the low-level voltage Low to the entire cycle can also represent the value of the torque, and the torque sensed by the torque sensing module 18 is determined by detecting the ratio of the width of the first voltage V1 in the first variable voltage signal to the entire cycle.

[0070] Therefore, the internal device 16 can transmit the torque sensed by the torque sensing module 18 to the outside through one conductive ring 142 or two conductive rings 142, 144, so that the conductive ring 14 can be used for communication. By measuring the voltage change of the conductive ring 14 externally, a first change voltage signal corresponding to the torque can be obtained, and the torque sensed by the torque sensing module 18 can be obtained by further analyzing the first change voltage signal.

[0071] The control signal and the first variable voltage signal described above are exemplified by pulse width modulation signals, but are not limited thereto, and may also be serial signals, such as Universal Asynchronous Receiver / Transmitter (UART) signals. The internal control module 26 encodes the detected torque value and transmits it via serial communication, so that the control signal and the first variable voltage signal form serial signals.

[0072] In addition, the internal device 16 in this embodiment further includes a power conversion module 28, which is disposed on the circuit board 27 and electrically connected to the conductive ring 142. The power conversion module 28 has a power output terminal 282, and the power output terminal 282 is electrically connected to the torque sensing module 18 and the internal control module 26. The power conversion module 28 converts the first power into a second power having a working voltage and outputs the second power from the power output terminal 282 to the torque sensing module 18 and the internal control module 26. The working voltage is less than the second voltage of the first variable voltage signal. The working voltage may be, for example, 5V, but is not limited thereto, and may also be 3.3V.

[0073] The power conversion module 28 may include a voltage regulator, such as a low-dropout linear voltage regulator, and the power conversion module 28 may stably provide a working voltage to the strain gauge 20, the readout circuit 22, and the internal control module 26 of the torque sensing module 18. Since the first voltage and the second voltage of the first variable voltage signal are both greater than the working voltage, the working voltage is not affected by the voltage variation of the first variable voltage signal. Therefore, one conductive ring 142 or two conductive rings 142, 144 simultaneously have the purpose of transmitting power and communicating, and no other conductive rings are required. In one embodiment, an internal battery (not shown) may also be provided on the shaft 10, and the internal battery supplies power to the power conversion module 28 to generate the second power.

[0074] In addition, in the present embodiment, the torque detection device 12 further includes at least one conductive member 32 and an external device 34. The at least one conductive member 32 contacts the at least one conductive ring 14 in a sliding contact manner. In the present embodiment, the at least one conductive member 32 is two in number and contacts the two conductive rings 142 and 144 respectively. Each of the conductive members 322 and 324 can be, for example, a carbon brush or a metal sliding plate. When the conductive rings 142 and 144 rotate with the shaft 10, the conductive members 322 and 324 are in sliding contact with the conductive rings 142 and 144. The external device 34 is located outside the shaft 10, that is, the external device 34 is not connected to the shaft 10 and does not rotate with the shaft 10.

[0075] The external device 34 includes a power supply module 36 and an external control module 42. The power supply module 36 is electrically connected to the two conductive members 322 and 324 and supplies the first power to the two conductive members 322 and 324. The first power is conducted to the conductive rings 142 and 144 through the conductive members 322 and 324. The voltage of the first power supplied by the power supply module 36 is the first voltage.

[0076] In this embodiment, the power supply module 36 includes a power supply 38 and a power conversion module 40. The power supply 38 may be, for example, a power supply or a battery, for providing direct current, the voltage of which is higher than the first voltage, for example, 20 to 48V. The power conversion module 40 may include a voltage stabilizer, the power conversion module 40 is electrically connected to the power supply and converts the power of the power supply 38 into the first power. A power output terminal 402 of the power conversion module 40 is electrically connected to the at least one conductive member 322, for example, it may be directly electrically connected or electrically connected to the conductive member 322 through a current limiting resistor (not shown).

[0077] The external control module 42 is electrically connected to the at least one conductive member 322, and the external control module 42 analyzes the first variable voltage signal to obtain the torque sensed by the torque sensing module 18. The external control module 42 may be, for example, a microcontroller, and the external control module 42 determines the change in voltage on the conductive members 322 and 324 to analyze the first variable voltage signal. In this embodiment, the external device 34 includes a comparator circuit 44, and the external control module 42 is electrically connected to the conductive member 322 through the comparator circuit 44, that is, the comparator circuit 44 is electrically connected between the conductive member 322 and the external control module 42, and the comparator circuit 44 may be, for example, a comparator formed by an operational amplifier. In addition, the power supply module 36 may also include another power conversion module 46, which converts the power of the power source 38 into the working voltage required by the external control module 42 and / or the comparator circuit 44.

[0078] The comparator circuit 44 has two input terminals and an output terminal, wherein one input terminal is connected to the conductive member 322, and the other input terminal is used to input a reference voltage Vref, and the reference voltage Vref may be, for example, 8.5V. The output terminal of the comparator circuit 44 is electrically connected to the external control module 42. The comparator circuit 44 converts the first voltage and the second voltage into a digital high voltage Hi (e.g., 5V or 3.3V) and a digital low voltage Low (e.g., 0V) respectively, which are suitable for the external control module 42. Figure 3As shown, when the voltage on the conductive member 322 is the first voltage V1, the comparator circuit 44 outputs a digital high voltage Hi; when the voltage on the conductive member 322 is the second voltage V2, the comparator circuit outputs a digital low voltage Low. In other words, the voltage change output by the comparator circuit 44 corresponds to the voltage change of the first variable voltage signal, and the external control module 42 can analyze the first variable voltage signal through the output of the comparator circuit 44, and then determine the torque sensed by the torque sensing module 18. Since the first variable voltage signal is first converted into a digital voltage level by the comparator circuit 44 and then input into the external control module 42, the external control module 42 can process the digital first variable voltage signal faster. Preferably, the external control module 42 processes the output of the comparator circuit 44 with an interrupt to speed up the response speed.

[0079] Alternatively, the external control module 42 has a built-in analog / digital converter and is electrically connected to the at least one conductive member 322 via a voltage divider circuit (not shown). The voltage divider circuit divides the first voltage and the second voltage and inputs the divided voltages into the analog / digital converter of the external control module 42 to convert the analog voltage into a corresponding digital value. Therefore, the external control module 42 can also analyze the first variable voltage signal and further determine the torque sensed by the torque sensing module 18.

[0080] In order to eliminate unexpected voltage changes caused by bouncing between the conductive members 322, 324 and the conductive rings 142, 144, in this embodiment, the external control module 42 further determines the frequency of the first variable voltage signal, and when the frequency of the first variable voltage signal meets the predetermined frequency, analyzes the first variable voltage signal to obtain the torque sensed by the torque sensing module 18. Therefore, it is possible to avoid the situation where the external control module 42 misjudges the first variable voltage signal due to bouncing between the conductive members 322, 324 and the conductive rings 142, 144.

[0081] In the first embodiment, the internal device 16 transmits the torque sensed by the torque sensing module 18 to the outside, that is, one-way transmission. Other preferred embodiments are provided later to illustrate embodiments in which two-way transmission is possible between the internal device 16 and the external device 34 .

[0082] Figure 4The figure shows a torque detection device 48 of a torque detection assembly according to a second preferred embodiment of the present invention, which is based on the structure of the first embodiment. The external device 34 further includes an external voltage adjustment circuit 50, which is electrically connected to the at least one conductive member 322 and the external control module 42. The external voltage adjustment circuit 50 can be controlled to change the voltage of the first power on the at least one conductive ring 142. The external control module 42 controls the external voltage adjustment circuit 50 to change the voltage of the first power on the at least one conductive ring 142 according to a control instruction to form a second variable voltage signal, and the second variable voltage signal varies between the first voltage and a third voltage, and the third voltage is less than the first voltage.

[0083] In this embodiment, the external voltage adjustment circuit 50 includes a Zener diode ZD2 and a switch element S2 connected in series. The Zener diode ZD2 and the switch element S2 are sequentially connected in series between the two conductive elements 322 and 324. The switch element S2 is a BJT, but is not limited thereto and may also be a MOSFET. The structure of the external voltage adjustment circuit 50 is substantially the same as that of the internal adjustment circuit 24, and the connection relationship thereof is not repeated here.

[0084] The switch element S2 is electrically connected to the external control module 42 and is turned on or off by the control of the external control module 42; wherein, when the switch element S2 is turned off, the first power has the first voltage, and when the switch element S2 is turned on, the Zener diode ZD2 collapses in reverse, so that the first power has the third voltage, that is, the voltage across the two conductive members 322 and 324 is the third voltage, and the third voltage is the collapse voltage of the Zener diode ZD2. The third voltage is less than the first voltage, and the third voltage can be equal to the second voltage, for example, the third voltage is 7V. The third voltage can also be different from the second voltage, but greater than the working voltage of the second power.

[0085] For example, the protocol between the external control module 42 and the internal control module 26 may be predefined, for example, the control command specifies a predetermined torque, and the internal control module 26 generates the first variable voltage signal only when the torque sensed by the torque sensing module 18 reaches the predetermined torque, so as to correspond to the torque sensed by the torque sensing module 18. The internal control module 26 does not generate the first variable voltage signal before the torque sensed by the torque sensing module 18 reaches the predetermined torque.

[0086] In this embodiment, the second variable voltage signal is a pulse width modulation signal, and the external control module 42 outputs a corresponding control signal to the switch element S2 according to the value of the predetermined torque to generate the second variable voltage signal. The control signal is also a pulse width modulation signal. Preferably, the frequency of the control signal and the second variable voltage signal is a predetermined frequency, and the predetermined frequency is between 200 and 300 Hz. In this embodiment, it is 250 Hz, that is, the period of the control signal and the second variable voltage signal is 4 ms. The purpose of setting the predetermined frequency is to enable the second variable voltage signal to be distinguished from the unexpected variable voltage generated during the bounce when a bounce occurs between the conductive members 322, 324 and the conductive rings 142, 144.

[0087] For example, the control signal uses a high voltage level to represent the value of the predetermined torque when the control signal starts to transmit, and the width of the pulse of the high voltage level represents the value of the predetermined torque. However, the present invention is not limited to this, and the width of the pulse of the low voltage level can also represent the value of the predetermined torque. The relationship between the value of the predetermined torque and the duty cycle of the pulse width modulation signal is similar to that in the first embodiment. Figure 3 In one embodiment, the control signal and the second variable voltage signal may also be serial signals.

[0088] The internal control module 26 is electrically connected to the at least one conductive ring 142 and analyzes the second variable voltage signal to obtain the control instruction. In this embodiment, the internal device 16 includes a voltage divider circuit 52, which is electrically connected to the at least one conductive ring 142 and the internal control module 26. The voltage divider circuit 52 is composed of two resistors. The voltage divider circuit 52 divides the first voltage and the third voltage and inputs them to an analog / converter of the internal control module 26 to convert the voltage of the second variable voltage signal into a corresponding digital value. The internal control module analyzes the second variable voltage signal to determine the predetermined torque specified by the control instruction.

[0089] Alternatively, the comparator circuit 44 of the first embodiment may be used to generate a digital voltage level change corresponding to the second varying voltage signal.

[0090] In order to eliminate unexpected voltage changes caused by bouncing between the conductive members 322, 324 and the conductive rings 142, 144, in this embodiment, the internal control module 26 further determines the frequency of the second variable voltage signal, and when the frequency of the second variable voltage signal meets the predetermined frequency, analyzes the second variable voltage signal to obtain the control instruction.

[0091] Therefore, the internal control module 26 can continuously obtain the torque sensed by the torque sensing module 18, and when the torque sensed by the torque sensing module 18 reaches the predetermined torque, the internal voltage adjustment circuit 24 is controlled to generate the first variable voltage signal. The external control module 42 can analyze the first variable voltage signal and know that the torque sensed by the torque sensing module 18 has reached the set predetermined torque. When applied to an electric tool, the external control module 42 can provide feedback to the motor of the electric tool for corresponding control.

[0092] Figure 5 The torque detection device 54 of the torque detection assembly according to a third preferred embodiment of the present invention is shown. The structure is based on the structure of the second embodiment, but the difference is that the internal device 16 further includes at least another internal voltage adjustment circuit 56. The internal control module 26 can output a control signal to the other internal voltage adjustment circuit 56 according to a sensed electrical signal to generate a third variable voltage signal. The voltage of the third variable voltage signal varies between the first voltage and a fourth voltage. The fourth voltage is the breakdown voltage of the Zener diode ZD3 of the other internal voltage adjustment circuit 56, and the fourth voltage is different from the second voltage and the third voltage and is greater than the working voltage. The sensed electrical signal can be an electrical signal corresponding to the torque sensed by the torque sensing module 18, or the internal device further includes a sensor 58, and the sensor 58 senses a physical quantity of the shaft 10. For example, the sensor 58 is a temperature sensor, and the physical quantity is temperature.

[0093] The external control module 42 can be electrically connected to the conductive member 322 via a voltage divider circuit 60 , and obtain the voltage on the conductive member 322 via the voltage divider circuit 60 to determine whether it is the first variable voltage signal or the third variable voltage signal.

[0094] In addition, the internal device 16 further includes at least another external voltage adjustment circuit 62. The external internal control module 26 can output a control signal to the other external voltage adjustment circuit 62 according to another control instruction to generate a fourth variable voltage signal, the voltage of the fourth variable voltage signal varies between the first voltage and a fifth voltage, the fifth voltage is the breakdown voltage of the Zener diode ZD4 of the other external voltage adjustment circuit 62, and the fifth voltage is different from the second voltage, the third voltage and the fourth voltage and is greater than the working voltage. The other control instruction can, for example, specify a predetermined physical quantity (such as a predetermined temperature). The internal control module 26 can obtain the voltage on the conductive rings 142 and 144 through the voltage divider circuit 52 to determine whether it is the second variable voltage signal or the fourth variable voltage signal. When the physical quantity sensed by the sensor 58 reaches the predetermined physical quantity, the internal control module 26 controls the other internal voltage adjustment circuit 56 to generate the third variable voltage signal.

[0095] Figure 6 The torque detection assembly 200 of the fourth preferred embodiment of the present invention is shown. It is based on the structure of the first embodiment and further includes two bearings 64 and a housing 66. The two bearings 64 are sleeved on the shaft 10. In the axial direction of the shaft 10, the two bearings 64 are located outside the two conductive rings 142 and 144, and the outer ring surfaces of the two bearings 64 are against the inner wall of the housing 66. The conductive rings 142 and 144 and the internal device 16 are located in the housing 66. Each of the conductive members 322 and 324 is penetrated in the housing 66 and contacts each of the conductive rings 142 and 144 in a sliding contact manner. Therefore, the torque sensed by the torque sensing module 18 can also be transmitted to the outside as a first variable voltage signal. The torque detection assembly 200 of this embodiment can be applied to the middle axis of a bicycle, for example, and the two ends of the shaft 10 are connected to two cranks respectively, so as to detect the torque generated by the shaft 10 when the user of the bicycle steps on the cranks.

[0096] In addition, the bearing 64 and the housing 66 of this embodiment can also be applied to the second and third embodiments.

[0097] The above descriptions are only preferred feasible embodiments of the present invention. Any equivalent changes made by applying the description and claims of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A torque detection device for detecting the torque of a shaft; the torque detection device comprises: At least one conductive ring is disposed on the shaft, and the at least one conductive ring receives a first power in a sliding contact manner; An internal device is disposed on the shaft and includes a torque sensing module, an internal voltage adjustment circuit and an internal control module, wherein: The torque sensing module senses the torque of the shaft and generates a corresponding electrical signal; The internal voltage adjustment circuit is electrically connected to the at least one conductive ring, and the internal voltage adjustment circuit can be controlled to change the voltage of the first power on the at least one conductive ring; The internal control module is electrically connected to the torque sensing module and the internal voltage adjustment circuit. The internal control module determines the torque sensed by the torque sensing module based on the electrical signal, and the internal control module controls the internal voltage adjustment circuit to change the voltage of the first power on the at least one conductive ring to form a first variable voltage signal based on the torque sensed by the torque sensing module, wherein the first variable voltage signal varies between a first voltage and a second voltage, and the second voltage is less than the first voltage.

2. The torque detection device as described in claim 1, wherein the internal device includes a power conversion module, the power conversion module is electrically connected to the at least one conductive ring, the power conversion module has a power output end, the power output end is electrically connected to the torque sensing module and the internal control module, the power conversion module converts the first power into a second power with a working voltage and outputs the second power from the power output end to the torque sensing module and the internal control module; the working voltage is less than the second voltage of the first variable voltage signal.

3. The torque detection device as claimed in claim 1, wherein the internal voltage adjustment circuit comprises a Zener diode and a switch element connected in series, the switch element is electrically connected to the internal control module and is controlled by the internal control module to be turned on or off; wherein, When the switching element is turned off, the first power has the first voltage, and when the switching element is turned on, the Zener diode causes the first power to have the second voltage.

4. The torque detection device as described in claim 1 comprises at least one conductive member, which contacts the at least one conductive ring in a sliding contact manner; and an external device, including a power supply module and an external control module; the power supply module is electrically connected to the at least one conductive member and supplies the first power to the at least one conductive member, and the first power is transmitted to the at least one conductive ring through the at least one conductive connection; the external control module is electrically connected to the at least one conductive member, and the external control module analyzes the first variable voltage signal to obtain the torque sensed by the torque sensing module.

5. The torque detection device as described in claim 4, wherein the external device includes a comparator circuit, the comparator circuit electrically connects the at least one conductive member and the external control module, and the comparator circuit converts the first voltage and the second voltage into a digital high-level voltage and a digital low-level voltage suitable for the external control module, respectively.

6. The torque detection device as described in claim 4, wherein the external device includes a voltage divider circuit, the voltage divider circuit electrically connects the at least one conductive member and the external control module, and the voltage divider circuit divides the first voltage and the second voltage and inputs them into the internal control module.

7. The torque detection device as claimed in claim 4, wherein the external control module determines the frequency of the first variable voltage signal, and when the frequency of the first variable voltage signal meets a predetermined frequency, analyzes the first variable voltage signal to obtain the torque sensed by the torque sensing module.

8. The torque detection device as claimed in claim 4, wherein the external device comprises an external voltage adjustment circuit, the external voltage adjustment circuit is electrically connected to the at least one conductive member and the external control module, and the external voltage adjustment circuit can be controlled to change the voltage of the first power on the at least one conductive ring; the external control module controls the external voltage adjustment circuit to change the voltage of the first power on the at least one conductive ring to form a second variable voltage signal according to a control instruction, wherein, The second variable voltage signal varies between the first voltage and a third voltage, and the third voltage is less than the first voltage. The internal control module is electrically connected to the at least one conductive ring and analyzes the second variable voltage signal to obtain the control instruction.

9. The torque detection device as claimed in claim 8, wherein the external voltage adjustment circuit comprises a Zener diode and a switch element connected in series, the switch element is electrically connected to the external control module and is controlled by the external control module to be turned on or off; wherein, When the switching element is turned off, the first power has the first voltage, and when the switching element is turned on, the Zener diode causes the first power to have the third voltage. 10 . The torque detection device as claimed in claim 8 , wherein the internal control module determines the frequency of the second variable voltage signal, and analyzes the second variable voltage signal to obtain the control instruction when the frequency of the second variable voltage signal meets a predetermined frequency.

11. The torque detection device as claimed in claim 8, wherein the internal device comprises a voltage divider circuit, the voltage divider circuit electrically connects the at least one conductive ring and the internal control module, and the voltage divider circuit divides the first voltage and the third voltage and inputs the divided voltages into the internal control module.

12. A torque detection assembly, comprising: a shaft; and A torque detection device comprises at least one conductive ring and an internal device, wherein: The at least one conductive ring is disposed on the shaft, and the at least one conductive ring receives a first power in a sliding contact manner; The internal device is disposed on the shaft and includes a torque sensing module, an internal voltage adjustment circuit and an internal control module, wherein: The torque sensing module senses the torque of the shaft and generates a corresponding electrical signal; The internal voltage adjustment circuit is electrically connected to the at least one conductive ring, and the internal voltage adjustment circuit can be controlled to change the voltage of the first power on the at least one conductive ring; The internal control module is electrically connected to the torque sensing module and the internal voltage adjustment circuit. The internal control module determines the torque sensed by the torque sensing module based on the electrical signal, and the internal control module controls the internal voltage adjustment circuit to change the voltage of the first power on the at least one conductive ring to form a first variable voltage signal based on the torque sensed by the torque sensing module, wherein the first variable voltage signal varies between a first voltage and a second voltage, and the second voltage is less than the first voltage.

13. The torque detection assembly as claimed in claim 12, comprising at least one conductive member contacting the at least one conductive ring in a sliding contact manner; and An external device includes a power supply module and an external control module; the power supply module is electrically connected to the at least one conductive member and supplies the first power to the at least one conductive member, and the first power is transmitted to the at least one conductive ring through the at least one conductive connection; the external control module is electrically connected to the at least one conductive member, and the external control module analyzes the first variable voltage signal to obtain the torque sensed by the torque sensing module.

14. The torque detection assembly as described in claim 12 comprises two bearings, a shell and at least one conductive member, the two bearings are sleeved on the shaft, and the outer ring surfaces of the two bearings are against the inner wall of the shell; the conductive ring and the internal device are located in the shell, and the at least one conductive member is penetrated by the shell and contacts the at least one conductive ring in a sliding contact manner.

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