JP3071153B2 - Torque detecting device and bicycle with auxiliary power provided with the device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting a torque acting on a drive shaft, and an auxiliary power unit for detecting a change in driving load due to human power by the device and controlling an auxiliary power device for assisting human power. It is about bicycles.

[0002]

2. Description of the Related Art A motor is connected to a driving wheel of a bicycle, and in the case of manual driving, the motor is driven in accordance with the magnitude of a load applied to a pedal, so that auxiliary power is applied to the driving of the bicycle by manual power, and 2. Description of the Related Art A bicycle with an auxiliary power that can drive a bicycle by driving is known. As a method of measuring the driving force applied by human power, for example, Japanese Patent Laid-Open No. 4-100
Japanese Patent Application Laid-Open No. 790 discloses a method in which a torsion bar is used as a crankshaft, and the amount of torsion of the torsion bar is detected by a potentiometer, a strain gauge, or the like provided on the torsion bar, and the rotational torque is measured.

[0003]

However, since the potentiometer and the strain gauge are provided on a rotating shaft, it is necessary to take out signals from these detection values using a slip ring, a brush, etc. It is difficult to accurately detect the rotational torque because noise is likely to be mixed due to wear and wear.

An object of the present invention is to detect a rotational torque applied to a rotating drive shaft on a fixed side in a non-contact manner by a combination of a magnet and a magnetic sensor on a fixed frame or a combination of a light emitting element and a light receiving element. It is an object of the present invention to provide a torque detecting device capable of performing the above-mentioned operation and an auxiliary powered bicycle equipped with the detecting device.

[0005]

In order to solve the above problems, a torque detecting device according to the present invention comprises a drive shaft (30) rotatably provided on a frame (26) and a drive shaft (30) concentric with the drive shaft. An output shaft (3) that is provided and is rotatable relative to the drive shaft;
An urging means (70) acting to prevent a phase shift between the drive shaft (30) and the output shaft (3), and an output from the drive shaft (30) by a load acting on the output shaft (3). A detector (8) for detecting a value corresponding to the phase shift when a phase shift occurs in the shaft (3), and the detector (8) includes a drive shaft (30) and an output shaft ( 3) having an inner ring (81) and an outer ring (83) which are concentrically protruded from each other and fit into each other with a margin, and the same number of the inner rings (81) and the outer rings (83) are matched in phase with each other. A detection window (82) (84) is formed, a magnet (85) fixed on the frame (26) and located between the inner ring (81) and the outer ring (83), and an inner ring (81 ) And a pair of magnetic sensors (86) and (87) are provided so as to sandwich the outer ring (83), and output signals from the two magnetic sensors (86) and (87) are compared.
0) and a detecting means (100) for detecting a value corresponding to a phase shift between the output shaft (3) and the output shaft (3). The auxiliary powered bicycle of the present invention is provided with a wheel (32) that is pivotally supported by a frame (26) and is rotatable relative to the drive shaft (30) that is driven by human power and that is relatively rotatable with the drive shaft. The drive shaft (30) and the wheel (32) are connected to each other by an urging means (70) acting to prevent a phase shift between the two, and an auxiliary power unit is connected to the drive system of the drive wheel. Detecting section (8) for detecting a value corresponding to the phase shift when a phase shift occurs between the drive shaft (30) and the wheel (32) due to a load acting on the wheel (32). For controlling the power assisting device in response to a signal from the controller, wherein the detector (8) is configured as described above.

[0006]

[Operation and Effect] When no load acts on the output shaft (3) and the drive shaft (30) and the output shaft (3) rotate integrally, the inner ring (81) on the drive shaft (30) side and The outer ring (83) on the output shaft (3) side rotates integrally without causing a phase shift. When the detection windows (82) (84) of the inner and outer rings (81) (83) face the magnetic sensors (86) (87), the magnetic sensors (86) (87)
The magnetic field lines from (5) are detected, but the detection windows (82) (82), (84) (8
When the magnetic wall surface between 4) faces the magnetic sensors (86) and (87), the magnetic force lines are blocked by the wall surfaces, and the magnetic force lines are not detected. When the inner rings (81) and (83) rotate, the magnetic sensors (86) and (87) can obtain outputs represented by waveforms. When the inner and outer rings (81) and (83) rotate integrally without causing a phase shift, the phases of output waveforms obtained by the magnetic sensors (86) and (87) do not shift.

However, when a load acts on the output shaft (3), the output shaft (3) is moved against the drive shaft (30) against the urging means (70).
, The inner ring (81) and the outer ring (83) are out of phase. As a result, the output waveform of the inner ring side magnetic sensor (86) and the outer ring side magnetic sensor (87)
Also produces a phase shift. The detecting means (100) compares the phase shift and detects a value corresponding to the phase shift between the drive shaft and the output shaft.

When the above torque detecting device is applied to a bicycle with auxiliary power, a petal arm (54) is connected to a drive shaft (30), and a sprocket wheel (32) driven by a rear wheel is connected to an output shaft.
In the case of (3), the detecting means (100) controls the auxiliary power according to the load acting on the drive wheel of the bicycle (10), and the pedaling force on the petal can be reduced. Magnet (85) and magnetic sensor (86) (87) mounted on non-rotating frame (26)
Thus, the phase shift between the drive shaft (30) and the output shaft (3) can be measured in a non-contact manner. Therefore, a slip ring or the like is not required for extracting the torque signal, and noise due to friction and wear can be prevented from being mixed. Since the detection is performed by the magnetic sensors (86) and (87), even if the sensor and the magnet (85) are covered with dust and mud adheres, the detection is not hindered.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a two-wheeled bicycle (1
An example in which the present invention is applied to 0) will be described. However, the present invention can be applied to a front-wheel drive bicycle and other human-powered driving devices. In the following description, a drive shaft (30) connected to the petal (56) and an output shaft (3) driven and rotated by the drive shaft (30) (in the bicycle of the embodiment, the drive shaft (3
The normal rotation of the wheel (32) disposed concentrically at 0) means the direction of rotation when the bicycle is traveling.

As shown in FIG. 1, a bicycle with auxiliary power (10) has a front wheel (14) and a handlebar at the front of a main frame (12).
(16), and a rear portion is provided with a rear wheel (18) serving as a driving wheel. Near the center of the main frame (12), the upper end has a saddle
A seat tube (22) provided with (20) is provided, and a cylindrical frame (26) pivotally supporting a pedal mechanism (24) is provided at a lower end of the seat tube (22). The crankshaft (30) of the pedal mechanism (24) is connected to the wheel (32) via an elastic body (70), as will be described later, and a sprocket fitted to the axle (34) of the rear wheel (18). An endless chain (38) is stretched between (36) and the wheel (32) to enable power transmission.

A pulley (41) is fitted on the axle (34) of the rear wheel (18). The pulley (41) is in timing with a motor (40) serving as an auxiliary power unit provided on the frame (12). It is linked via a belt (42). The motor (40) uses a battery (44) attached to the seat tube (22) as a power source, and the motor (40) rotates to directly drive the rear wheel (18). The output of the motor (40) is
It is controlled by the control unit (48) based on a torque signal from a detection unit (100) described later. The configuration of the control unit (48),
The operation is disclosed in the above-mentioned known example, and the description is omitted.

As shown in FIGS. 1 to 3, the pedal mechanism (24) includes a drive shaft (30) pivotally supported by a cylindrical frame (26) at the lower end of the seat tube (22), and the drive shaft (30). ), Projecting in opposite directions perpendicular to the shaft (30), respectively, and a petal arm (54) rotating integrally with the drive shaft (30), and a pedal (56) pivotally supported at the tip of the petal arm (54). ), An annular engagement plate (60) fixed to the drive shaft (30), and a wheel (32) rotatably fitted on the engagement plate (60).

As is well known in the art, a square shaft (31) fitted to the petal arm (54) is provided at the wheel-side end of the drive shaft (30).
Is protruded. The square axis (31) is opposed to the petal arm (5
The petal arm (54) is fixed to the drive shaft (30) by the screw (59) by fitting into the square hole (55) opened at the center of the base end of 4).

A short cylindrical inner ring (81) is protruded from the inner surface of the engaging plate (60) concentrically with the plate, and five pressing pieces (62) are protruded inwardly at equal intervals near the outer periphery. Is done.

As shown in FIGS. 2 to 4, the wheel (32) has an engagement plate (6) inserted into a central round hole (68) via a bearing (63).
The inner ring (81) of (0) is fitted. The wheel (32) has a short cylindrical outer ring (83) projecting inward at the edge of the round hole (68), a sprocket (64) is formed on the outer periphery, and five window holes (66) in the circumferential direction. Are set up at equal intervals.

An elastic body (70) such as a coil spring is provided in each window hole (66) in the direction of rotation delay of the wheel (32), and the base end of the elastic body (70) is fixed to the wheel (32). I do. The distal ends of the elastic bodies (70) are attached so as to abut against the pressing pieces (62) of the engagement plate (60). When the pedal (56) is depressed, the drive shaft (30) and the engagement plate (60) rotate integrally, and the five pressing pieces (62) facing the elastic body (70) are respectively elastic bodies (70). Press to rotate the wheel (32).

When a load acts on the wheel (32), the rotation of the wheel (32) is delayed against the elastic body (70). That is, a phase shift occurs between the wheel (32) and the drive shaft (30). However, in the embodiment, the phase is restricted by a stopper (not shown) provided at an appropriate position so that a phase shift of 15 ° or more does not occur.

An inner ring (81) of the engagement plate (60) and a wheel (3)
The outer ring (83) of 2) is fitted concentrically so that an annular space is created between the two. The inner ring (81) and the outer ring (83) are made of a magnetic material, that is, a metal having a property of blocking a magnetic field, and have the same number of detection windows (82) and (84) penetratingly opened at equal intervals in the circumferential direction. . The detection window (82) of the embodiment is rectangular, and the inner ring (81)
The upper detection window (82) has the same shape, and the detection window (84) on the outer ring (83) has the same shape. The width W in the rotation direction of the detection window (82) on the outer ring (83) is set to be equal to the inner ring (81) for the reason described later.
It is slightly larger than that of the upper detection window (84).

The frame (26) is provided with a mount (88) protruding toward the wheel (32). The mount (88) has a pair of magnets (85) and a pair of opposed magnets (85). Magnetic sensors (86) and (87) are provided. The magnetic sensor of the embodiment is a Hall element (86a) (87a). Magnet (85) is inner ring
(81) and the outer ring (83), one Hall element (86a) is located inside the inner ring (81), and the other Hall element
(87a) is located outside the outer ring (83) and the magnet (85)
And both Hall elements are located on the diameter of the inner and outer rings (81) and (83). The wheel (32) and the frame (26) are provided with a split cover (27) so as to accommodate the outer race-side Hall element (87a) therein. The two Hall elements (86a) (87a) are connected to the detecting means (100). When the inner ring (81) rotates,
The inner ring side Hall element (86a) detects a magnetic field when the detection window (82) of the inner ring (81) passes through the element, and detects the magnetic field when the magnetic wall surface between the detection windows (82) and (82) passes. The magnetic field is blocked by the wall and the magnetic field is not detected.

FIG. 6A shows the waveform of the output obtained by detecting the magnetic field of the inner ring side magnetic sensor (86). When the outer ring (83) rotates, the outer ring-side Hall element (87a) similarly detects a change in the magnetic field, and can obtain an output waveform shown in FIG. 6B. Since 12 detection windows (82) and (84) are opened in the inner and outer rings (81) and (83), respectively, the waveform has 12 peaks.

Each detection window (82) of the inner ring (81) is a magnet (85)
Corresponding to the diameter difference between the inner ring (81) and the outer ring (83), so that the time for passing through the magnet and the time for each detection window (84) of the outer ring (83) to pass through the magnet (85) are the same. The width W in the rotation direction of the detection window (84) of the outer ring (83) is slightly longer than that of the inner ring (81). Accordingly, the output waveforms of the two inner and outer Hall elements (86a) and (87a) obtained when they make one rotation are obtained by repeating 360 ° by the number 12 of the detection windows (82) and (84) every 30 °. Yes, isomorphic.

When a phase shift occurs between the inner ring (81) and the outer ring (83), a phase shift also occurs in the output waveforms of the two inner and outer Hall elements (86a) (87a). The detecting means (100) detects this phase shift and sends a signal to the control section (48) of the motor (40), which is auxiliary power, according to the phase shift.

FIG. 8 shows an example of the detecting means (100). The output waveform obtained from the inner ring side Hall element (86a) is amplified by the differential amplifier (101), and by the AD converter (102),
It outputs a digitized voltage signal. This voltage signal is converted into an angle by a look-up table (103).

FIG. 9A shows the waveform of the voltage signal. Since one peak of the waveform is symmetrical about the peak, the symmetrical positions of the rising and falling sides of the waveform, for example, 10 ° and 20 ° are determined. Can not. Then, the voltage signal is differentiated, and the increase / decrease detection circuit (10
According to 4), as shown in FIG. 9B, a differential value that takes a positive value when the waveform of A rises and a negative value when it falls is obtained. When the differential value is a positive value, the value at A is used as it is, and when the differential value is a negative value, a value obtained by subtracting the value at A from 30 ° is used.

The above operations are similarly performed on the outer ring side Hall element (87a) side by the differential amplifier (101a), the AD converter (102), the look-up table (103a), and the increase / decrease detection circuit (104a).

The signals from the two increase / decrease detection circuits (104) (104a) are compared by a phase difference comparison circuit (105). This is a waveform from the increase / decrease detection circuit (104a) of the inner ring side Hall element (86a) that detects a change in magnetic field due to the inner ring (81) that rotates integrally with the drive shaft (30), and rotates integrally with the wheel (32). Increase / decrease detection circuit (104) that detects a change in the magnetic field due to the outer ring (83)
This is performed by calculating the difference due to the phase shift of the waveform from.

However, if the waveform is represented by repetition of 0 to 30 °, the same position is set between 0 ° and 30 °. Therefore, FIG.
As shown in FIG. 0A, the waveform on the inner ring side Hall element (86a) side,
A range occurs in which the difference between the waveforms of the outer ring-side Hall element (87a) shown in FIG. 10B takes a negative value. In this case, the correction circuit (106)
A value of 30 ° is added to make a positive value. The angle of the positive value is converted into a torque signal by the look-up table (107) and sent to the control unit (48).

The waveform on the inner ring side Hall element (86a) side and FIG.
If the waveform of the outer ring side Hall element (87a) is shifted to B by 山 of one peak (15 ° in the embodiment), the phase shift cannot be detected, but in the embodiment, the inner ring (81) and the outer ring (83) Does not occur because there is no deviation of 15 ° or more.

However, when the pedal (56) is not depressed,
Or, even if the pedal (56) is depressed, the load applied to the wheel (32) is small, and the wheel (32) is rotating integrally with almost no displacement with respect to the drive shaft (30). In FIG. 6, since there is no displacement in the rotational direction between the drive shaft (30) and the wheel (32), as shown in FIG. 6, the waveform on the inner ring side Hall element (86a) side and the waveform on the outer ring side Hall element (87a) in FIG. Are in phase.

If the pedal (56) is depressed at the time of starting, accelerating, climbing a hill or the like of the bicycle (10), a large load is applied to the wheel (32). When this load exceeds the spring force of the elastic body (70) and acts on the wheel (32), the pressing piece (62)
0) is compressed and deformed, and the wheel (32) is rotationally displaced in the opposite direction relative to the drive shaft (30). Therefore, the inner ring (8
A phase difference occurs between 1) and the outer ring (83), for example, as shown in FIG.
Waveform on inner ring side Hall element (86a) side and outer ring side Hall element
The phase of the waveform of (87a) is shifted. The control unit (48) controls the motor (40) according to the deviation.

A light emitting element is provided in place of the magnet (85), and a light receiving element is provided in place of the hall elements (86a) and (87b) in the same manner as described above. The present invention can be variously modified within the scope of the claims, such as detecting a value corresponding to the phase shift of the output shaft.

[Brief description of the drawings]

FIG. 1 is a front view of a bicycle with auxiliary power.

FIG. 2 is an exploded view of the pedal mechanism according to the first embodiment.

FIG. 3 is a front view of a wheel to which a biasing unit is attached.

FIG. 4 is a cross-sectional view of a state where a wheel, a magnet, and a magnetic sensor are mounted.

FIG. 5 is a plan view showing a mounted state of a magnet and a magnetic sensor.

FIG. 6A is a developed view of an inner ring and an output waveform obtained by detecting an inner ring side Hall element, and FIG. 6B is a developed view of an outer ring and an output waveform obtained by detecting an outer ring side Hall element.

FIG. 7 shows a state where the phase is shifted from the state of FIG. 6;

FIG. 8 is a block diagram of a detecting means.

9A shows a waveform of a voltage signal, and FIG. 9B shows a waveform of a differential value thereof.

FIG. 10 shows a range in which the difference in phase shift takes a negative value.

[Explanation of symbols]

 (10) Bicycle (26) Cylindrical frame (30) Crankshaft (32) Wheel (70) Elastic body (86) Inner ring magnetic sensor (87) Outer ring magnetic sensor (100) Detection means

Continuation of the front page (56) References JP-A-8-26172 (JP, A) JP-A-63-269029 (JP, A) JP-A-4-363636 (JP, A) JP-A-63-154925 (JP) , A) Fully open sho 56-102440 (JP, U) Fully open sho 57-4730 (JP, U) Fully open sho 60-125575 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB) G01L 3/14 B62M 23/02

Claims (3)

(57) [Claims] A drive shaft (30) rotatably provided on a frame (26), an output shaft (3) provided coaxially with the drive shaft and rotatable relative to the drive shaft, and a drive shaft (30). ) And the output shaft (3), biasing means (70) acting to prevent a phase shift between them, and a drive shaft (30) and an output shaft (3) by a load acting on the output shaft (3). And a detector (8) for detecting a value corresponding to the phase shift when a phase shift occurs in the detector (8), wherein the detector (8) is concentric with the drive shaft (30) and the output shaft (3). The inner ring (81) that is projected from the
And the outer ring (83), the inner ring (81) and the outer ring (83) are formed with the same number of detection windows (82) and (84) in phase with each other, and are fixed on a frame (26) and fixed to the frame (26). (81) and a magnet (85) positioned between the outer ring (83) and a pair of magnetic sensors (86) sandwiching the inner ring (81) and the outer ring (83) between the magnets.
(87) facing each other, detecting means for comparing output signals from the two magnetic sensors (86) and (87) and detecting a value corresponding to a phase shift between the drive shaft (30) and the output shaft (3). Torque detector with (100). 2. A wheel (32) pivotally supported by a frame (26) and driven by human power is provided on an outer periphery of the drive shaft (30) so as to be rotatable relative to the drive shaft, and the wheel is connected to the drive wheel. The drive shaft (30) and the wheel (32) are linked by an urging means (70) that acts to prevent a phase shift between the two, and the auxiliary power unit is linked to the drive system of the drive wheels. When a phase shift occurs between the drive shaft (30) and the wheel (32) due to a load acting on the wheel (32), a signal from the detection unit (8) that detects a value corresponding to the phase shift is used. In a bicycle with an auxiliary power that controls the power assist device in response, the detector (8) protrudes concentrically with the drive shaft (30) and the wheel (32), and fits in a state where there is room in each other.
1) and an outer ring (83) .The inner ring (81) and the outer ring (83) have the same number of detection windows (82) and (84) in phase with each other, and are fixed on the frame (26). A magnet (85) located between the inner ring (81) and the outer ring (83) and a pair of magnetic sensors (86) sandwiching the inner ring (81) and the outer ring (83) between the magnets
(87) facing each other, detecting means for comparing output signals from the two magnetic sensors (86) and (87) and detecting a value corresponding to a phase shift between the drive shaft (30) and the wheel (32) ( An auxiliary powered bicycle composed of 100). 3. A drive shaft (30) rotatably mounted on a frame (26), an output shaft (3) concentric with the drive shaft and rotatable relative to the drive shaft, and a drive shaft (30). ) And the output shaft (3), a biasing means (70) acting to prevent a phase shift between them, and a drive shaft (30) and an output shaft (3) by a load acting on the output shaft (3). And a detector (8) for detecting a value corresponding to the phase shift when a phase shift occurs in the detector (8), wherein the detector (8) is concentric with the drive shaft (30) and the output shaft (3). The inner ring (81) that is projected from the
And the outer ring (83), the inner ring (81) and the outer ring (83) are formed with the same number of detection windows (82) and (84) in phase with each other, and are fixed on a frame (26) and fixed to the frame (26). (81) and a light emitting element located between the outer ring (83) and the inner ring (81) between the light emitting element and the light emitting element.
And a pair of light receiving elements are arranged facing each other so as to sandwich the outer ring (83). The output signals from the two light receiving elements are compared and the drive shaft (3
A torque detecting device comprising detecting means for detecting a value corresponding to a phase difference between the output shaft (0) and the output shaft (3).