WO2022181045A1

WO2022181045A1 - Torque detection device and mechanism

Info

Publication number: WO2022181045A1
Application number: PCT/JP2021/048629
Authority: WO
Inventors: 佑介丹治
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2021-02-25
Filing date: 2021-12-27
Publication date: 2022-09-01

Abstract

The present invention addresses the problem of enabling torque applied to a rotating body to be detected. This torque detection device (9) comprises: a crystal device (90) attached to a rotating body that rotates about a rotation axis with respect to a non-rotating body; a first coil (91) wound around the rotating body about the rotation axis and electrically connected to the crystal device (90); a second coil (92) held by the non-rotating body, wound around the outer peripheral surface of the first coil (91) with a gap therebetween, and magnetically coupled to the first coil (91); a pair of input ends (931, 932) which are respectively connected to both ends of the second coil (92) and to which an AC voltage source (93) is connected; a current sensor (94) that is held by the non-rotating body and detects current flowing through the second coil (92); and a torque detection unit (95) that is held by the non-rotating body and detects torque applied to the rotating body, on the basis of the phase difference between the phase of the output voltage from the voltage source (93) and the phase of the current detected by the current sensor (94).

Description

Torque detection device and instrument

The present disclosure relates generally to torque sensing devices and instruments. More particularly, the present disclosure relates to torque sensing apparatus comprising quartz devices and instruments comprising torque sensing apparatus.

Patent Document 1 describes a torque sensor that includes a contactless power supply device and a strain gauge for torque measurement. A torque sensor is provided in an electrically assisted bicycle.

A contactless power supply device includes a power transmission unit having a first antenna coil, and a power reception unit having a second antenna coil magnetically coupled to the first antenna coil.

The power transmission section is provided on the fixed side board.

The power receiving unit includes a rectifier circuit that rectifies an AC signal induced in the second antenna coil, a power supply circuit that receives the output of the rectifier circuit via a low-pass filter and outputs power of a predetermined voltage, the rectifier circuit and the low-pass filter. a load modulation circuit connected to a connection point with the power receiving side to change the impedance of the power receiving side to transmit data to the power transmitting section. The strain gauge operates with power from the power supply circuit. The power receiving unit is provided on the rotating substrate. The rotation-side substrate and the strain gauge are fixed to the crankshaft and rotate together with the crankshaft.

In the torque sensor of Patent Document 1, it is necessary to provide a rotating body such as a crankshaft with a circuit component such as a power supply circuit for supplying power to the strain gauge.

WO2015/108153

An object of the present disclosure is to provide a torque detection device capable of detecting torque applied to a rotating body and simplifying the configuration of the rotating body, and an instrument including the same.

A torque detection device according to one aspect of the present disclosure includes a crystal device, a first coil, a second coil, a pair of input terminals, a current sensor, and a torque detection section. The crystal device is attached to a rotating body. The rotating body rotates around the rotation axis with respect to the non-rotating body. The first coil is wound around the rotating body around the rotating shaft. The first coil is electrically connected with the crystal device. The second coil is held by the non-rotating body. The second coil is wound around the outer peripheral surface of the first coil with a gap interposed therebetween. The second coil is magnetically coupled with the first coil. The pair of input terminals are connected to both ends of the second coil. An AC voltage source is connected to the pair of input terminals. The current sensor is held by the non-rotating body. The current sensor detects current flowing through the second coil. The torque detector is held by the non-rotating body. The torque detector detects torque applied to the rotating body based on a phase difference between the phase of the output voltage from the voltage source and the phase of the current detected by the current sensor.

An instrument according to one aspect of the present disclosure includes the torque detection device, the crankshaft as the rotating body, and a pedal that is connected to the crankshaft and rotates the crankshaft by receiving a pedaling force from the outside. Prepare.

FIG. 1 is a circuit diagram of a torque detection device according to one embodiment. FIG. 2 is a perspective view of a rotating body to which the torque detection device is attached. FIG. 3 is a cross-sectional view of a rotating body to which the torque detection device is attached. FIG. 4 is a diagram showing an example of the relationship between the phase of the voltage applied to the torque detection device and the phase of the current flowing through the torque detection device. FIG. 5 is a side view of a power-assisted bicycle provided with the torque detection device of the same. FIG. 6 is a block diagram of the drive system for the electrically assisted bicycle same as the above. FIG. 7 is a diagram for explaining the assist ratio of the above-mentioned electrically assisted bicycle. FIG. 8 is a diagram for explaining the connection relationship between two crystal devices of the torque detection device. FIG. 9 is a perspective view of a rotating body to which a modified torque detection device is attached.

(1) Overview Each drawing described in the following embodiments is a schematic drawing, and the ratio of the size and thickness of each component in each drawing does not necessarily reflect the actual dimensional ratio. Not necessarily.

As shown in FIG. 1, the torque detection device 9 according to this embodiment includes a crystal device 90, a first coil 91, a second coil 92, a pair of

input ends

931 and 932, a current sensor 94, a torque A detection unit 95 is provided. As shown in FIGS. 2 and 3, the crystal device 90 is attached to a rotating body 98 . The rotating body 98 rotates around the rotating shaft 980 with respect to the non-rotating body 99 . The first coil 91 is wound around the rotating body 98 around the rotating shaft 980 . The first coil 91 is electrically connected with the crystal device 90 . The second coil 92 is held by a non-rotating body 99 . The second coil 92 is wound around the outer peripheral surface of the first coil 91 with a gap G1 interposed therebetween. The second coil 92 is magnetically coupled with the first coil 91 . A pair of

input terminals

931 and 932 are connected to both ends of the second coil 92, respectively. An AC voltage source 93 is connected to the pair of

input terminals

931 and 932 . A current sensor 94 is held by a non-rotating body 99 . A current sensor 94 detects the current flowing through the second coil 92 . The torque detector 95 is held by a non-rotating body 99 . Torque detector 95 detects the torque applied to rotating body 98 based on phase difference Δθ between the phase of the output voltage from voltage source 93 and the phase of the current detected by current sensor 94 .

When torque is applied to the rotating body 98 from the outside, the rotating body 98 deforms according to the applied torque. The crystal device 90 deforms (expands and contracts) according to the deformation of the rotor 98, and its series capacitance Cc (described later) changes according to the deformation. The phase of the current (alternating current) flowing through the second coil 92 changes according to changes in the series capacitance Cc of the crystal device 90 .

FIG. 4 shows an example of the relationship between the voltage applied from the voltage source 93 to the second coil 92 and the current flowing through the second coil 92. As shown in FIG. In FIG. 4, "V0" is the waveform of the output voltage of the voltage source 93, and "I0" is the current flowing through the second coil 92 when no torque is applied to the rotor 98 (the crystal device 90 is not deformed). A current waveform "I1" indicates the waveform of the current flowing through the second coil 92 when a predetermined torque is applied to the rotor 98 (the crystal device 90 is deformed). In FIG. 4, for the sake of convenience, the phase of the current I0 is shown to be equal to the phase of the output voltage V0 (where Δθ ₀ is the phase difference Δθ when no torque is applied to the rotor 98, Δθ ₀ =0). there is

When torque is applied to the rotor 98, the phase of the current flowing through the second coil 92 changes according to the change in the series capacitance Cc of the crystal device 90, as shown in FIG. In the example of FIG. 4, the current I1 flowing through the second coil 92 when torque is applied to the rotating body 98 is compared to the current I0 flowing through the second coil 92 when no torque is applied to the rotating body 98. , the phase with respect to the voltage V0 is advanced by Δt1/T0. Here, “T0” is the period of the output voltage from voltage source 93 . Assuming that the phase difference Δθ in the state where the torque is applied to the rotor 98 is Δθ ₁ , the relationship |Δθ ₁ -Δθ ₀ |=Δt1/T0 is established.

Thus, when the rotating body 98 deforms, the phase difference Δθ between the phase of the output voltage from the voltage source 93 and the current detected by the current sensor 94 changes according to the deformation. The torque detector 95 can detect the torque applied to the rotating body 98 by detecting the change in the phase difference Δθ. Thus, the torque detection device 9 of the present embodiment detects the torque applied to the rotating body 98 by detecting the change in the phase difference Δθ.

Further, in the torque detection device 9 of this embodiment, the crystal device 90 is provided on the rotating body 98 , while the voltage source 93 , current sensor 94 and torque detection section 95 are provided on the non-rotating body 99 . The crystal device 90, the voltage source 93, and the current sensor 94 are connected via a first coil 91 and a second coil 92 that are magnetically coupled (transformer coupled). Therefore, in the torque detection device 9 of the present embodiment, there is no need to provide circuit components such as a power supply circuit in the rotating body 98, and the configuration of the rotating body 98 can be simplified compared to the torque sensor of Patent Document 1. Become.

The torque detection device 9 is used to detect torque applied to the rotating body 98 provided in the instrument 10 . In this embodiment, the device 10 is a power-assisted bicycle 100 (see FIG. 5), and the rotating body 98 is the crankshaft 29 of the power-assisted bicycle 100 . As shown in FIGS. 5 and 6 , the power-assisted bicycle 100 as the device 10 includes pedals 26 in addition to the torque detection device 9 and the crankshaft 29 . The pedal 26 is connected to a crankshaft 29 and rotates the crankshaft 29 upon receiving a pedaling force from the outside (user). The electrically assisted bicycle 100 further includes wheels 20 that rotate according to the rotation of the crankshaft 29 .

According to the electrically assisted bicycle 100 of the present embodiment, it is possible to detect the torque applied to the crankshaft 29 by the torque detection device 9 .

(2) Details Hereinafter, the torque detection device 9 of the present embodiment and a power-assisted bicycle 100 including the torque detection device 9 will be described with reference to FIGS. 1 to 8. FIG.

(2.1) Overall Configuration of Electric-Assisted Bicycle First, the overall configuration of the electrically-assisted bicycle 100 of the present embodiment will be described with reference to FIGS. 5 and 6. FIG. A motor-assisted bicycle 100 is a bicycle in which a user's stepping force (stepping force, human power driving force) is assisted by a motor 50 . The “user” here means the rider of the electrically assisted bicycle 100, particularly the driver of the electrically assisted bicycle 100. Hereinafter, the “electrically assisted bicycle 100” may be simply referred to as the bicycle 100.

As shown in FIGS. 5 and 6, the bicycle 100 includes a drive system 1 and a main body 2.

As shown in FIG. 5, the bicycle 100 runs on the running surface 101. Hereinafter, unless otherwise specified, the running surface 101 of the bicycle 100 is assumed to be parallel to the horizontal plane H1 (see FIG. 5). However, in practice, the running surface 101 does not have to be parallel to the horizontal plane H1, and may be inclined with respect to the horizontal plane H1, or may be a surface with irregularities. Also, hereinafter, the direction in which the bicycle 100 travels is defined as the "forward direction", the opposite direction to the forward direction is defined as the "rearward direction", and the forward direction and the rearward direction are collectively defined as the "front-rear direction D1". However, these directional definitions are not intended to limit the manner in which the bicycle 100 is used. In addition, the arrows indicating each direction in the drawings are only shown for explanation and are not substantial.

(2.2) Main Body As shown in FIG. 5, the main body 2 includes a frame 7, a plurality of (two in the illustrated example) wheels 20, a front fork 22, a handlebar 23, a saddle 24, and a pair of cranks. It has an arm 25 , a pair of pedals 26 , a power transmission body 27 and a crankshaft 29 .

A plurality of wheels 20 are members that support the frame 7 on the running surface 101 . The main body 2 of this embodiment has one front wheel 201 and one rear wheel 202 as the plurality of wheels 20 . The front wheel 201 has a hub 281 in the center and the rear wheel 202 has a hub 282 in the center. A front wheel 201 and a rear wheel 202 are attached to the frame 7 .

The front wheel 201 is the front wheel of the two wheels 20 aligned in the front-rear direction D1. Front wheel 201 is supported by leg 221 so as to be rotatable around an axis extending in the left-right direction. The front wheels 201 are the wheels 20 that do not receive power transmission from the motor 50 in this embodiment.

The rear wheel 202 is the rear wheel of the two wheels 20 aligned in the front-rear direction D1. The rear wheel 202 is rotatably supported by a plurality (here, a pair) of chain stays 77 around an axis extending in the left-right direction.

A rear sprocket 292 is attached to the rear wheel 202 . The rear sprocket 292 is concentric with and integrally attached to the hub 282 of the rear wheel 202 . The rear sprocket 292 is composed of, for example, a plurality of sprockets.

The front fork 22 supports the front wheel 201. The front fork 22 has a pair of legs 221 , a crown 222 and a steering column 223 . A crown 222 connects the upper ends of the pair of legs 221 . A steering column 223 protrudes from the crown 222 . A front wheel 201 is rotatably attached to the pair of legs 221 via a shaft passed through a hub 281 . The rotation axis of front wheel 201 is parallel to running surface 101 . A central axis (longitudinal axis) of the steering column 223 extends rearward as it goes upward from the crown 222 and is inclined with respect to the running surface 101 .

The handle 23 is attached to the upper end of the steering column 223 and fixed to the front fork 22 . The steering column 223 is passed through the head pipe 71 of the frame 7 and is rotatably attached to the frame 7 . The rotation axis of steering column 223 is substantially parallel to the longitudinal direction of steering column 223 . Therefore, the handle 23 can rotate the front wheel 201 with the axis along the longitudinal direction of the steering column 223 as the rotation axis.

The frame 7 is a framework to which a plurality of wheels 20, front forks 22, handle 23, saddle 24, battery unit 4 and control system 3 are attached. The material of the frame 7 is, for example, an aluminum alloy containing aluminum as a main component. However, the material of the frame 7 is not limited to aluminum alloy, and may be, for example, iron, chromium molybdenum steel, high-tensile steel, titanium, or magnesium. Further, the material of the frame 7 is not limited to metal, and may be carbon, wood, bamboo, or fiber-reinforced synthetic resin (eg, CFRP; Carbon Fiber Reinforced Plastics).

The frame 7 includes a head pipe 71, an upper pipe 72, a reinforcing pipe 73, a lower pipe 74, a standing pipe 75, a plurality of (only one shown in FIG. 5) seat stays 76, and a plurality of (in FIG. 5 chainstays 77 (only one shown) and brackets 78 . As used in this disclosure, "pipe" means an elongated hollow member. The cross-sectional shape of pipes of the present disclosure may be, for example, circular (including perfect circles, ovals and ellipses), rectangular (including squares), hexagonal, or octagonal.

The head pipe 71 supports the front fork 22. The central axis of the head pipe 71 is inclined with respect to the running surface 101 so as to go rearward as it goes upward. A steering column 223 is passed through the head pipe 71 so that the central axis of the head pipe 71 and the central axis of the steering column 223 are aligned. This allows the head pipe 71 to rotatably support the steering column 223 . The rotation axis of the steering column 223 is the same as the central axis of the head pipe 71 .

The upper pipe 72 connects the head pipe 71 and the standing pipe 75 . A longitudinal front end of the upper pipe 72 is connected to the head pipe 71 . A longitudinal rear end of the upper pipe 72 is connected to a standing pipe 75 . The central axis of the upper pipe 72 is inclined with respect to the running surface 101 so as to go downward as it goes rearward. However, the upper pipe 72 does not have to be inclined with respect to the running surface 101 . The upper pipe 72 may be omitted.

The reinforcement pipe 73 is a reinforcement member for reinforcing the connecting portion between the standing pipe 75 and the upper pipe 72 . The reinforcing pipe 73 connects the standing pipe 75 and the upper pipe 72 . The reinforcement pipe 73 may be omitted.

The standing pipe 75 holds the saddle 24. A lower longitudinal end of the standing pipe 75 is connected to a bracket 78 . The central axis of the standing pipe 75 is inclined with respect to the running surface 101 so as to go rearward as it goes upward from the lower end. The longitudinal rear end of the upper pipe 72 is connected to the intermediate portion of the vertical pipe 75 . The term “intermediate portion” as used herein means a portion of the standing pipe 75 in the longitudinal direction excluding the lower end and the upper end. The upper pipe 72 may be connected to the upper end of the standing pipe 75 .

The lower pipe 74 connects the bracket 78 and the head pipe 71 . A longitudinal front end of the lower pipe 74 is connected to the head pipe 71 . A longitudinal rear end of the lower pipe 74 is connected to a bracket 78 . The central axis of the lower pipe 74 is inclined with respect to the running surface 101 so as to go upward as it goes forward from the rear end in the longitudinal direction. A battery 41 of the battery unit 4 is detachably attached to the lower pipe 74 .

A plurality of (here, one pair as an example) chain stays 77 support the shaft of the rear wheel 202 . A longitudinal front end of each chain stay 77 is connected to a bracket 78 . The longitudinal rear end of each chain stay 77 is connected to the rear end of the corresponding seat stay 76 . The pair of chain stays 77 are separated in the left-right direction, and the rear wheel 202 is rotatably attached to the rear ends of the pair of chain stays 77 via a shaft passed through a hub 282 . The rotation axis of the rear wheel 202 is substantially parallel to the running surface 101 and coincides with the center axis of the shaft supporting the rear wheel 202 .

A plurality of (here, one pair as an example) seat stays 76 connect the chain stay 77 and the standing pipe 75 . The longitudinal rear end of each seat stay 76 is connected to the longitudinal rear end of the corresponding chain stay 77 . A longitudinal front end of each seat stay 76 is connected to an intermediate portion of the standing pipe 75 . A pair of seat stays 76 branch from the upper pipe 72 and are integrated with the upper pipe 72 . However, the seat stay 76 and the upper pipe 72 may be separate bodies.

The control system 3 is attached to the bracket 78 . The bracket 78 is formed in a substantially C shape when viewed from a direction orthogonal to both the up-down direction and the front-rear direction D1. The bracket 78 is connected to the longitudinal rear end of the lower pipe 74 , the longitudinal lower end of the standing pipe 75 , and the longitudinal front end of the chain stay 77 . Thereby, the longitudinal rear end of the lower pipe 74, the longitudinal lower end of the standing pipe 75, and the longitudinal front end of the chain stay 77 are fixed to each other.

The saddle 24 has a seat pillar 241 and a seat 242 on which the user sits. The seat pillar 241 is passed through the vertical pipe 75 along the central axis of the vertical pipe 75 . The seat pillar 241 protrudes downward from the seat portion 242 of the saddle 24 . The seat pillar 241 is inclined with respect to the running surface 101 so as to go forward as it goes downward. The seat pillar 241 is attached to the vertical pipe 75 so as to be movable along the central axis of the vertical pipe 75 .

The crankshaft 29 is rotatably held in the housing 31 of the control system 3 via bearings or the like. The crankshaft 29 is made of metal. A pair of crank arms 25 are attached to the crank shaft 29 as shown in FIG. The longitudinal direction of the crank arm 25 intersects (perpendicularly in the illustrated example) the rotation axis of the crankshaft 29 . The pair of crank arms 25 are arranged in a straight line when viewed in the rotation axis direction of the crankshaft 29 .

Each of the pair of pedals 26 is attached to one end of the corresponding crank arm 25 in the longitudinal direction opposite to the crankshaft 29 side. Each pedal 26 is rotatably attached to the corresponding crank arm 25 . The axis of rotation of the pedals 26 is substantially parallel to the axis of rotation of the crankshaft 29 . By pedaling the pedal 26 , the user can apply a human-powered rotational force (pedal force) to the crankshaft 29 .

A crank sprocket 291 is attached to the crankshaft 29 . The crank sprocket 291 is composed of a plurality of sprockets, for example, and constitutes a transmission together with the rear sprocket 292 . By changing the shift position of the transmission, the bicycle 100 can be shifted. The "shift position" here means the combination of the sprocket of the crank sprocket 291 and the sprocket of the rear sprocket 292, and corresponds to a so-called gear ratio.

The power transmission body 27 transmits the human power driving force (pedal force) from the user to at least one of the plurality of wheels 20 (here, the rear wheel 202). Also, the power transmission body 27 transmits the power output from the motor 50 to at least one of the plurality of wheels 20 (here, the rear wheel 202). The power transmission body 27 connects the crank sprocket 291 and the rear sprocket 292 . The power transmission body 27 is a chain that is spanned between the crank sprocket 291 and the rear sprocket 292 so as to be able to transmit power. Thereby, the power output from the motor 50 is transmitted to the rear wheel 202 via the power transmission body 27 . The power transmission body 27 may be, for example, a belt, shaft, wire, or gear.

(2.3) Drive System As shown in FIG. 6 , the drive system 1 includes a motor 50 , a control system 3 , a battery unit 4 , a detection device group 8 and an operation section 6 . The drive system 1 is a system that outputs a drive auxiliary output. The drive system 1 adds a drive assist output to the human power drive force (pedal force) and transmits the power to the rear wheels 202 via the power transmission body 27 .

(2.3.1) Motor The motor 50 gives power (drive auxiliary output) to the wheel 20 of the bicycle 100 . Motor 50 is provided near crankshaft 29 of bicycle 100 and is driven by electric power from battery 41 . The motor 50 is connected to the crank sprocket 291 via a speed reducer including, for example, planetary gears. Power of the motor 50 is transmitted to the crank sprocket 291 via a reduction gear or the like.

(2.3.2) Battery Unit The battery unit 4 has a battery 41 and a battery control section 42, as shown in FIG. The battery unit 4 is electrically connected with the control system 3 .

The battery 41 supplies power to the motor 50 via the control system 3 . In addition to the motor 50, the battery 41 also supplies power to, for example, the headlight of the main body 2, the operation unit 6, and the like. As the battery 41, a secondary battery such as a lithium ion secondary battery that can be repeatedly charged and discharged is used. The battery 41 is detachably attached to the lower pipe 74 . Note that the battery 41 may be arranged along the standing pipe 75 behind the standing pipe 75 .

Each time the bicycle 100 is used, the battery control unit 42 obtains the amount of power consumed by the battery 41 (battery power consumption) while the bicycle 100 is running (during use). Power consumption information representing battery power consumption is output from the battery control unit 42 to the control system 3 . Also, the battery control unit 42 manages the remaining amount of the battery 41 . Remaining amount information indicating the remaining amount of the battery 41 is output from the battery control section 42 to the control system 3 .

(2.3.3) Operation Unit The operation unit 6 receives an operation for turning on/off the motor 50 from the user. That is, the operation unit 6 receives an operation for selecting on/off of the assist using the power from the motor 50 from the user. The operation unit 6 may receive an operation for selecting the strength of the assist from the user. The operation part 6 is attached to the handle 23, for example. The operation unit 6 is electrically connected with the control system 3 .

(2.3.4) Control system The control system 3 is configured to perform assist control and regeneration control. Specifically, the control system 3 executes assist control for controlling the motor 50 based on the human power driving force (pedal force), the vehicle speed of the bicycle 100, the shift position (gear ratio) of the transmission, and the like. The human power driving force (pedal force) is detected by a pedal force detector F2, which will be described later. The vehicle speed is detected by a vehicle speed detector F1, which will be described later.

Also, the control system 3 executes processing related to regenerative control for charging the battery 41 with the electric power generated by the motor 50 during deceleration. For example, when the user operates the brake lever of the handlebar 23 while the bicycle 100 is traveling downhill, the control system 3 switches to the regenerative control mode and recovers the charge amount of the battery 41 by regenerative braking force. Note that the control system 3 may further perform lighting control related to the headlights.

The control system 3 has a processing unit 30, a storage unit 32, and a housing 31 that accommodates the processing unit 30, as shown in FIGS.

The housing 31 has a hollow, flat box shape. As shown in FIG. 5, housing 31 is secured to bracket 78 .

The processing unit 30 is mainly composed of a computer system having one or more processors and one or more memories. In the processing unit 30, the functions of each unit of the processing unit 30 are realized by one or more processors executing programs recorded in the memory. The program may be prerecorded in a memory, may be provided through an electric communication line such as the Internet, or may be provided by being recorded in a non-temporary recording medium such as a memory card.

The processing unit 30 has a detection unit 301 and a drive control unit 302, as shown in FIG. In other words, the processing unit 30 has a function as the detection unit 301 and a function as the drive control unit 302 .

The processing unit 30 is configured to acquire various electrical signals from the outside (battery unit 4, detection device group 8, and operation unit 6). The processing unit 30 executes processing related to assist control, regenerative control, etc. according to the acquired electrical signal.

In particular, the processing unit 30 executes processing related to assist control for driving the motor based on the assist ratio. The “assist ratio” in the present disclosure is the value of the ratio of electric power assistance (rotational power by the motor) to human power driving force (pedal force) (“electric power assistance”/“human power driving force”).

It should be noted that, for example, in Japan, the Road Traffic Law stipulates the upper limit of the assist ratio of electric power assistance to human power driving power for electric power assisted bicycles for each vehicle speed range. Specifically, in Japan, as shown in FIG. 7, for example, when the vehicle speed is less than 10 km/h, the maximum assist ratio between the human power driving force (see area R2) and the electric power assistance (see area R1) is 1:2. (The upper limit of the assist ratio of electric power assistance to manpower driving force is "2"). Further, when the vehicle speed is 24 km/h or more, the maximum assist ratio is stipulated to be 1:0 (the assist ratio of electric power assistance to human driving force is "0"). Therefore, in this embodiment, the processing unit 30 adjusts the assist ratio within a range in which the assist ratio of the bicycle 100 satisfies the above regulation. However, since road traffic laws may differ in each country, it is not essential for the processing unit 30 to consider the upper limit of the assist ratio.

The detection unit 301 includes, for example, a vehicle speed detection unit F1 and a pedaling force detection unit F2, as shown in FIG. The detection unit 301 receives sensor signals (electrical signals) from the detection device group 8 .

The detection device group 8 includes a vehicle speed detection device 81 and a pedaling force detection device 82, as shown in FIG.

The vehicle speed detection unit F1 detects the vehicle speed of the bicycle 100. Vehicle speed detection unit F<b>1 detects the vehicle speed of bicycle 100 based on a sensor signal from vehicle speed detection device 81 . The vehicle speed detection device 81 detects, for example, the rotational state of the wheel 20 (for example, the rear wheel 202) of the bicycle 100. FIG. Vehicle speed detection device 81 includes, for example, a magnet and a speed sensor. The magnets are located on the rear wheel 202 and rotate with the rear wheel 202 . The speed sensor is a Hall IC that detects the magnetic force of a magnet. The speed sensor is attached to the chain stay 77 of the frame 7, for example. A speed sensor detects the magnetic force of a magnet using, for example, the Hall effect. The speed sensor outputs a sensor signal based on the detection result to the control system 3 . The vehicle speed detection unit F1 detects the rotation state of the rear wheel 202 once, for example, each time the rear wheel 202 rotates once, based on the sensor signal from the speed sensor. Vehicle speed detection unit F1 detects the vehicle speed of bicycle 100 based on, for example, the number of rotations of rear wheel 202 per unit time and the diameter of rear wheel 202 . The vehicle speed detection unit F1 may detect the rotational state of the front wheels 201 in addition to or instead of the rear wheels 202. In this case, the magnets are arranged on the front wheels 201 and rotate together with the front wheels 201. Vehicle speed detector F1 calculates the current vehicle speed of bicycle 100 . The obtained calculation result is used for assist control and the like.

The pedaling force detection unit F2 detects the pedaling force as the human power driving force. The pedaling force detection unit F2 detects the pedaling force based on the sensor signal from the pedaling force detection device 82 . The pedaling force detection device 82 includes the torque detection device 9 . Details of the torque detection device 9 will be described in the next section. The pedaling force detection device 82 outputs a sensor signal based on the detected pedaling force (torque) to the control system 3 . The pedaling force detection unit F2 calculates a pedaling force (manpower driving force) from the detection result of the pedaling force detection device 82 or the like. The obtained calculation result is used for assist control and the like.

The drive control unit 302 determines the power (assist torque) to be output from the motor 50 based on the detection result of the vehicle speed detection unit F1 (current vehicle speed), the detection result of the pedaling force detection unit F2 (current pedaling force), and the like. The drive control unit 302 controls the motor 50 by outputting a drive control signal so that the motor 50 rotates at a predetermined rotational speed. In short, the processing unit 30 controls the assist ratio of the power from the motor 50 to the pedaling force (manpower driving force) based on the pedaling force (torque) detected by the torque detection device 9 .

The storage unit 32 is composed of a readable and writable memory. The storage unit 32 is, for example, a flash memory. The storage unit 32 is provided outside the processing unit 30 , but may be provided inside the processing unit 30 . That is, the storage unit 32 may be a built-in memory of the processing unit 30 . The storage unit 32 stores various data relating to assist control and the like.

(2.4) Pedal Force Detecting Device The pedaling force detecting device 82 detects the pedaling force (manpower driving force) from the user. The pedaling force detection device 82 includes a torque detection device 9 . The torque detection device 9 detects torque applied to the crankshaft 29 as the rotating body 98 .

As described above, the torque detection device 9 includes the crystal device 90, the first coil 91, the second coil 92, the pair of input ends 931 and 932, the current sensor 94, and the torque detection section 95. ing.

As shown in FIG. 2 , the crystal device 90 is attached to the crankshaft 29 as the rotating body 98 . In this embodiment, crystal device 90 includes crystal oscillator 900 . Note that the size of the crystal oscillator 900 is on the order of millimeters. In FIG. 2, the size of the crystal device 90 (crystal resonator 900) is exaggerated.

The crystal oscillator 900 includes, for example, a base, a crystal piece held by the base, a pair of electrodes connected to the crystal piece, and a cover fixed to the base so as to cover the crystal piece. The base is attached to the crankshaft 29 . In this embodiment, the base is attached to the outer peripheral surface of the crankshaft 29 (rotating body 98). The base deforms (distorts) according to the deformation (distortion) of the outer peripheral surface of the crankshaft 29 . The mounting location of the base is not limited to the outer peripheral surface of the crankshaft 29, and may be the inner peripheral surface of the crankshaft 29, for example. The crystal blank is held by the base and deforms (stretches) according to the deformation (distortion) of the base. That is, the crystal piece deforms (expands and contracts) according to the deformation (distortion) of the crank shaft 29 .

FIG. 1 shows an equivalent circuit of the crystal oscillator 900. As shown in FIG. An equivalent circuit of the crystal oscillator 900 is represented by a parallel circuit of a series circuit of an equivalent series resistance Rc, a series inductance Lc, and a series capacitance Cc, and a parallel capacitance _C0 . When the crystal blank deforms (expands and contracts), the value of the series capacitance Cc of the crystal resonator 900 changes.

As shown in FIG. 2 , the first coil 91 is wound around the crankshaft 29 as a rotating body 98 . The first coil 91 is spirally wound. The first coil 91 is wound around the crankshaft 29 around a resin bobbin, for example. Both ends of the first coil 91 are electrically connected to both ends of the crystal device 90 (a pair of electrodes of the crystal oscillator 900).

As shown in FIGS. 2 and 3, the second coil 92 is held by the housing 31 as the non-rotating body 99. As shown in FIG. The second coil 92 is wound around the outer peripheral surface of the first coil 91 . The second coil 92 is spirally wound. The second coil 92 is wound around a resin bobbin, for example. As shown in FIG. 3, there is a gap G1 between the second coil 92 and the first coil 91. As shown in FIG. Therefore, even if the first coil 91 rotates together with the rotating body 98 (crankshaft 29), the second coil 92 does not rotate. The second coil 92 is magnetically coupled (transformed) to the first coil 91 . The first coil 91 and the second coil 92 constitute a transformer Tr1.

As shown in FIG. 1, an AC voltage source 93 is connected between a pair of

input terminals

931 and 932 . Voltage source 93 is held in housing 31 as non-rotating body 99 . Voltage source 93 may be a high frequency power supply. The frequency of the AC voltage from the voltage source 93 is preferably, for example, the same or on the same order as the resonant frequency of the crystal device 900 .

The current sensor 94 is held by the housing 31 as the non-rotating body 99 . A current sensor 94 detects alternating current flowing through the second coil 92 .

The torque detector 95 is held by the housing 31 as the non-rotating body 99 . The torque detector 95 is connected to the voltage source 93 . The torque detector 95 receives a signal indicating information on the output voltage from the voltage source 93 . Information on the output voltage from the voltage source 93 includes information on the phase of the output voltage. The torque detector 95 is connected to the current sensor 94 . The torque detector 95 receives a signal indicating information on the alternating current detected by the current sensor 94 . Information on the alternating current detected by the current sensor 94 includes information on the phase of the alternating current. The torque detector 95 detects a phase difference Δθ between the phase of the output voltage from the voltage source 93 and the phase of the current detected by the current sensor 94 .

As described above, when the crystal blank deforms (expands and contracts) due to deformation of the crankshaft 29 (rotating body 98), the value of the series capacitance Cc of the crystal oscillator 900 changes. The phase difference Δθ between the phase of the output voltage from the voltage source 93 and the phase of the current flowing through the second coil 92 depends on the reactance (series capacitance Cc) of the crystal oscillator 900 . Therefore, when the value of the series capacitance Cc of the crystal oscillator 900 changes according to the torque applied to the crankshaft 29 (rotating body 98), the phase difference Δθ changes (see FIG. 4). Conversely, a change (amount of change) in the value of the series capacitance Cc of the crystal oscillator 900 can be detected from a change (amount of change) in the phase difference Δθ. can be detected. The relationship between the change in the phase difference Δθ and the torque applied to the crankshaft 29 is recorded in memory, for example, in the form of a data table, relational expression, or the like. In short, the torque detection unit 95 detects the rotation of the rotating body 98 based on the phase difference Δθ between the phase of the output voltage from the voltage source 93 and the phase of the current detected by the current sensor 94 (amount of change in the phase difference Δθ). Detects torque applied to (crankshaft 29).

In this embodiment, the torque detection device 9 includes two crystal devices 90 (crystal oscillators 900), as shown in FIG. Two crystal devices 90 (crystal oscillators 900 ) are attached to the peripheral surface of the crankshaft 29 . In this embodiment, the two crystal oscillators 900 are arranged side by side along the axial direction of the crankshaft 29 . In FIG. 1, only one of the two crystal devices 90 (crystal oscillators 900) is illustrated, and the illustration of the other is omitted. Hereinafter, the two crystal oscillators 900 are also referred to as a first crystal oscillator 901 and a second crystal oscillator 902 when they are distinguished from each other.

The series capacitance Cc of the first crystal oscillator 901 changes mainly according to deformation (expansion and contraction) in the first direction A1. The first direction A1 is a direction that intersects the rotation axis of the crankshaft 29 at an angle of 45 degrees when viewed from the radial direction of the crankshaft 29 . A first crystal oscillator 901 attached to the rotating body 98 so that its longitudinal direction (first direction A1) intersects the rotating shaft 980 at an angle of 45 degrees is mainly applied to the rotating body 98. is deformed (stretched) according to torque in the clockwise direction when viewed from the right side of the . The first crystal oscillator 901 detects deformation (distortion) of the crankshaft 29 in the first direction A1. The first crystal oscillator 901 is, for example, shaped like a rectangular plate elongated in the first direction A1.

The series capacitance Cc of the second crystal oscillator 902 changes mainly according to deformation (expansion and contraction) in the second direction A2. The second direction A2 is a direction that intersects the rotation axis of the crankshaft 29 at an angle of 135 degrees (−45 degrees) when viewed from the radial direction of the crankshaft 29 . A second crystal oscillator 902 attached to the rotating body 98 so that its longitudinal direction (second direction A2) intersects the rotating shaft 980 at an angle of 135 degrees is mainly applied to the rotating body 98. is deformed (stretched) according to torque in the counterclockwise direction when viewed from the right side of the . The second crystal oscillator 902 detects deformation (distortion) of the crankshaft 29 in the second direction A2. The second crystal oscillator 902 is, for example, shaped like a rectangular plate elongated in the second direction A2.

Thus, the two crystal oscillators 900 (the first crystal oscillator 901 and the second crystal oscillator 902) intersect the rotation axis of the crankshaft 29 (the rotation axis 980 of the rotating body 98) at different angles. , is attached to the crankshaft 29. As shown in FIG. By attaching two crystal devices 90 (crystal oscillators 900) to the rotating body 98 so that they intersect the rotating shaft 980 at different angles, it is possible to detect torques applied to the rotating body 98 in different directions. becomes. In this embodiment, the two crystal oscillators 900 are attached to the crankshaft 29 so that their longitudinal directions intersect each other at an angle of 90 degrees. The two crystal vibrators 900 have the same crystal piece shape. The two crystal oscillators 900 have the same crystal axis of the crystal piece with respect to the longitudinal direction. For example, both of the two crystal oscillators 900 are AT cut oscillators. The two crystal oscillators 900, each of which is an AT-cut oscillator, are configured so that, for example, when viewed from the radial direction of the rotating body 98, the thickness-shear vibration direction of the crystal oscillators 900 is 45 degrees from the rotation axis 980 of the rotating body 98 and It is attached to the rotor 98 so as to intersect at an angle of 135 degrees.

As shown in FIG. 8, two crystal devices 90 (a first crystal oscillator 901 and a second crystal oscillator 902) are electrically connected in parallel to the first coil 91. An equivalent circuit of the two crystal oscillators 900 connected in parallel is represented by, for example, the same circuit as the equivalent circuit of the crystal oscillator 900 shown in FIG. However, the equivalent circuit of two crystal oscillators 900 differs from the equivalent circuit of one crystal oscillator 900 in circuit constants (series capacitance Cc value, series inductance Lc value, etc.). The series capacitance Cc of the equivalent circuit of the two crystal oscillators 900 changes according to the deformation (expansion and contraction) of the first crystal oscillator 901 . Also, the series capacitance Cc of the equivalent circuit of the two crystal oscillators 900 changes according to the deformation (expansion and contraction) of the second crystal oscillator 902 . Two crystal devices 90 (crystal resonators 900) attached to a rotating body 98 so as to intersect the rotation axis 980 at different angles are connected in parallel to each other with respect to the voltage source 93 (here, the first coil 91). By connecting them, it becomes possible to detect different directions of torque applied to the rotating body 98 using one voltage source 93 .

The pedaling force detection device 82 detects the pedaling force from the user based on the torque detected by the torque detection device 9 .

Thus, the torque detection device 9 of the present embodiment can detect the torque applied to the rotating body 98 by detecting the change in the phase difference Δθ with the torque detection section 95 . Further, in the torque detection device 9 of the present embodiment, by connecting the crystal device 90 and the voltage source 93 via the transformer Tr1, the configuration of the rotating body 98 is simplified as compared with the torque sensor of Patent Document 1. becomes possible.

(3) Modifications The embodiment described above is merely one of various embodiments of the present disclosure. The above-described embodiment can be modified in various ways according to design and the like, as long as the object of the present disclosure can be achieved.

Modifications of the above embodiment are listed below. Modifications described below can be applied in combination as appropriate.

In the instrument 10 provided with the torque detection device 9 according to the present disclosure, the torque detection section 95, the control system 3, etc. include a computer system. A computer system is mainly composed of a processor and a memory as hardware. The function of the drive system 1 in the present disclosure is realized by the processor executing a program recorded in the memory of the computer system. The program may be recorded in advance in the memory of the computer system, may be provided through an electric communication line, or may be recorded in a non-temporary recording medium such as a computer system-readable memory card, optical disk, or hard disk drive. may be provided. A processor in a computer system consists of one or more electronic circuits, including semiconductor integrated circuits (ICs) or large scale integrated circuits (LSIs). Integrated circuits such as ICs or LSIs are called differently depending on the degree of integration, and include integrated circuits called system LSI, VLSI (Very Large Scale Integration), or ULSI (Ultra Large Scale Integration). In addition, FPGAs (Field-Programmable Gate Arrays), which are programmed after the LSI is manufactured, or logic devices capable of reconfiguring the connection relationships inside the LSI or reconfiguring the circuit partitions inside the LSI, shall also be adopted as processors. can be done. A plurality of electronic circuits may be integrated into one chip, or may be distributed over a plurality of chips. A plurality of chips may be integrated in one device, or may be distributed in a plurality of devices. A computer system, as used herein, includes a microcontroller having one or more processors and one or more memories. Accordingly, the microcontroller also consists of one or more electronic circuits including semiconductor integrated circuits or large scale integrated circuits.

Also, it is not an essential configuration that the multiple functions of the control system 3 are integrated in one housing. The components of the control system 3 may be distributed over multiple housings. Conversely, multiple functions in control system 3 may be combined in one housing. Furthermore, at least part of the functions of the control system 3 may be realized by a cloud (cloud computing) or the like.

The crystal device 90 is not limited to the crystal resonator 900. In one modification, the crystal device 90 may be a SAW (Surface Acoustic Wave) filter. A SAW filter comprises a piezoelectric substrate made of quartz and two interdigitated electrodes (IDTs) formed on the piezoelectric substrate. The SAW filter excites a surface acoustic wave only when an electrical signal of a selected frequency determined by the characteristics of the piezoelectric substrate and the cycle of the IDT is input. The selected frequency changes according to the deformation of the piezoelectric substrate of the SAW filter. The torque detector 95 detects deformation of the piezoelectric substrate of the SAW filter and, in turn, torque applied to the rotating body 98 (crankshaft 29) based on the change in the selected frequency.

In one modification, the first coil 91 may be attached to the rotating body 98 so as to cover the crystal device 90, as shown in FIG. As a result, the torque detection device 9 can be made compact. In this modification, the second coil 92 also covers the crystal device 90, as shown in FIG. The entire crystal device 90 may not be covered with the first coil 91 , and for example, only a portion of the crystal device 90 may be covered with the first coil 91 .

The angle between the first direction A1 and the rotation axis of the crankshaft 29 is not limited to 45 degrees. The angle formed by the second direction A2 and the crankshaft 29 is not limited to 135 degrees. In one modification, the angle between the first direction A1 and the rotation axis of the crankshaft 29 may be in the range of 30 to 60 degrees, or in the range of 40 to 50 degrees. The angle between the second direction A2 and the rotation axis of the crankshaft 29 may be in the range of 120 to 150 degrees, or may be in the range of 130 to 140 degrees. In a modified example, the angle between the first direction A1 and the rotation axis of the crankshaft 29 may be 90 degrees, and the angle between the second direction A2 and the rotation axis of the crankshaft 29 may be 0 degrees.

In one modification, the torque detection device 9 may include one or more than three crystal devices 90 . For example, an additional crystal device 90 may be attached to the back side of the two crystal devices 90 on the outer peripheral surface of the rotating body 98 .

In one modification, the torque detector 95 may be part of the processor 30 .

In one modification, the second coil 92, the voltage source 93, the current sensor 94, and the torque detector 95 may be held by a non-rotating body 99 other than the housing 31, such as the lower pipe 74. The second coil 92, the voltage source 93, the current sensor 94, and the torque detector 95 may be held by non-rotating bodies 99 different from each other.

The device 10 is not limited to the bicycle (electrically assisted bicycle) 100. In a modified example, the device 10 may be a vehicle with an electric power assist (a unicycle, a tricycle, etc.) other than the electric power assist bicycle 100, or may be an electric bicycle that can be moved only by the power from the motor 50. However, it may be a vehicle (two-wheeled vehicle, three-wheeled vehicle, etc.) that does not have a power mechanism such as a motor. In one variation, device 10 may be a fitness device, specifically an ergometer. The fitness equipment further comprises a body resting on the ground. The body rotatably holds the crankshaft 29 .

(4) Summary As described above, the torque detector (9) of the first aspect includes a crystal device (90), a first coil (91), a second coil (92), and a pair of input terminals. (931, 932), a current sensor (94), and a torque detector (95). A crystal device (90) is mounted on a rotating body (98). The rotating body (98) rotates about the rotation axis (980) with respect to the non-rotating body (99). A first coil (91) is wound around a rotating body (98) around a rotating shaft (980). The first coil (91) is electrically connected with the crystal device (90). The second coil (92) is held by a non-rotating body (99). The second coil (92) is wound around the outer peripheral surface of the first coil (91) with a gap (G1) interposed therebetween. The second coil (92) is magnetically coupled with the first coil (91). A pair of input terminals (931, 932) are connected to both ends of the second coil (92). An AC voltage source (93) is connected to the pair of input terminals (931, 932). A current sensor (94) is held on a non-rotating body (99). A current sensor (94) detects the current flowing through the second coil (92). A torque detector (95) is held by a non-rotating body (99). A torque detector (95) detects a rotor (98) based on a phase difference (Δθ) between the phase of the output voltage from the voltage source (93) and the phase of the current detected by the current sensor (94). Detects the torque applied to

According to this aspect, the torque applied to the rotating body (98) can be detected. In addition, compared to the torque sensor of Patent Document 1, it is possible to simplify the configuration of the rotating body (98).

The torque detection device (9) of the second aspect includes two crystal devices (90) in the first aspect. Two crystal devices (90) are attached to the peripheral surface of the rotating body (98). The two crystal devices (90) are attached to the rotating body (98) so as to intersect the rotating shaft (980) at different angles.

According to this aspect, it is possible to detect different directions of torque applied to the rotating body (98).

In the torque detection device (9) of the third aspect, in the second aspect, the two crystal devices (90) are electrically connected in parallel to the first coil (91).

In the torque detection device (9) of the fourth aspect, in any one of the first to third aspects, the first coil (91) is attached to the rotating body (98) so as to cover the crystal device (90) be done.

According to this aspect, it is possible to make the torque detection device (9) compact.

A fifth aspect of the instrument (10) comprises the torque detection device (9) of any one of the first to fourth aspects, a crankshaft (29) as a rotating body (98), and a crankshaft (29) and a pedal (26) connected to the crankshaft (26) for rotating the crankshaft (29) by receiving a pedaling force from the outside.

According to this aspect, it is possible to detect the torque applied to the crankshaft (29) of the instrument (10) by the torque detection device (9).

The instrument of the sixth aspect, in the fifth aspect, further comprises a wheel (20) that rotates according to the rotation of the crankshaft (29).

According to this aspect, the torque detection device (9) makes it possible to detect the torque applied to the crankshaft (29) of the instrument (10) with wheels (20).

In the instrument of the seventh aspect, in the sixth aspect, based on the torque detected by the motor (50) that powers the wheel (20) and the torque detection device (9), the assist ratio of the power to the pedaling force is determined. and a controlling processor (3).

According to this aspect, it is possible to adjust the assist ratio based on the torque detected by the torque detection device (9).

The instrument of the eighth aspect, in the fifth aspect, further comprises a body that rotatably holds the crankshaft (29) and rests on the ground.

9 torque detector 90 crystal device 91 first coil 92

second coil

931, 932 input end 93 voltage source 94 current sensor 95 torque detector 98 rotating body 980 rotating shaft 99 non-rotating body 10 instrument 20 wheel 26 pedal 29 crankshaft G1 Air gap Δθ Phase difference

Claims

a quartz crystal device mounted on a rotating body that rotates about an axis of rotation relative to a non-rotating body;
a first coil wound around the rotating body around the rotating shaft and electrically connected to the crystal device;
a second coil held by the non-rotating body, wound around the outer peripheral surface of the first coil with a gap therebetween, and magnetically coupled to the first coil;
a pair of input terminals connected to both ends of the second coil and connected to an AC voltage source;
a current sensor held by the non-rotating body and detecting a current flowing through the second coil;
It is held by the non-rotating body and detects the torque applied to the rotating body based on the phase difference between the phase of the output voltage from the voltage source and the phase of the current detected by the current sensor. a torque detection unit for
comprising
Torque detector.
Equipped with two crystal devices,
The two crystal devices are attached to the peripheral surface of the rotating body,
The two crystal devices are attached to the rotating body so as to intersect the rotating shaft at different angles.
The torque detection device according to claim 1.
The two crystal devices are electrically connected in parallel with each other with respect to the first coil.
The torque detection device according to claim 2.
The first coil is attached to the rotating body so as to cover the crystal device,
A torque detection device according to any one of claims 1 to 3.
A torque detection device according to any one of claims 1 to 4;
a crankshaft as the rotating body;
a pedal that is connected to the crankshaft and rotates the crankshaft by receiving a pedaling force from the outside;
comprising
instrument.
Further comprising a wheel that rotates according to the rotation of the crankshaft,
6. A device according to claim 5.
a motor that powers the wheels;
a processing unit that controls an assist ratio related to the power with respect to the pedaling force based on the torque detected by the torque detection device;
further comprising
7. A device according to claim 6.
a body that rotatably holds the crankshaft and rests on the ground;
6. A device according to claim 5.