JPH1159555A - Shaft drive type moving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the input torque into a shaft member without increasing the cost and the weight in a shaft drive type moving device, and save the space. SOLUTION: A shaft drive type moving device 1 is provided with a drive mechanism 2 to transmit the power to a wheel 3 through a rotary shaft member 4. A torsion detecting means 7 to detect the torsion of the shaft member 4 and a torque calculating means 8 to calculate the input torque to be applied to the shaft member 4 from the torsion detected by the torsion detecting means 7 are provided, and the signal to indicate the input torque obtained by the torque calculating means 8 is transmitted to a power control means 9 to control the main power of the moving device 1 or the auxiliary power to the main power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft-driven moving device for transmitting power to wheels via a rotating shaft member.

[0002]

2. Description of the Related Art Assisted bicycles (or electric bicycles) having a motor as an auxiliary power source are known as mobile devices for detecting main power and controlling a power source according to the main power. Bicycles are designed to detect the driver's leg strength and obtain auxiliary power according to the magnitude by the motor, thereby compensating for the lack of the driver's leg strength to reduce the burden on human power. .

[0003] Means for detecting the leg strength of the driver include a mechanical torque sensor attached to a crank or a chain wheel.

[0004]

However, the conventional assisted bicycle has a problem in that the provision of the torque sensor causes an increase in cost and weight and a problem in securing an arrangement space for the torque sensor.

[0005] For example, when a mechanical torque sensor is attached to a crank, a large arrangement space and a dedicated housing are required, which causes an increase in cost and weight. Also, when a mechanical torque sensor is attached to the chain wheel, a large space is required in the housing of the chain wheel.

Accordingly, an object of the present invention is to detect input torque to a shaft member without significantly increasing the cost and weight of a shaft-driven moving device, and to save space.

[0007]

In order to solve the above-mentioned problems, the present invention provides a torsion detecting means for detecting a torsion of a rotating shaft member, and an input to the shaft member from the torsion detected by the torsion detecting means. There is provided a torque calculating means for calculating a torque, and a power control means for performing a power control by calculating a main power of the moving apparatus or an auxiliary power for the main power from the input torque obtained by the torque calculating means.

Therefore, according to the present invention, the input torque can be obtained from the torsion of the shaft member, and the power control can be performed according to the input torque.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a conceptual diagram showing the basic configuration of a shaft-driven moving device according to the present invention.

In the shaft-driven moving device 1, the driving mechanism 2 is a mechanism for transmitting power to the wheels 3, and the power is transmitted to the wheels 3 via the rotating shaft member 4. In other words, the power conversion unit 5 is provided at the input end of the shaft member 4, and the power is converted into the rotational force of the shaft member 4 by the power conversion unit 5. And
A power converter 6 is provided at the output end of the shaft member 4, and the torque of the shaft member 4 is converted into the torque of the wheels 3 by the power converter 6. The power transmission from the power conversion unit 6 to the wheels 3 may be performed directly or indirectly via another power transmission device.

For example, in the case of an assisted bicycle, the wheel 3 corresponds to the rear wheel of the bicycle, and when a crank (not shown) is rotated by the driver's leg force, which is power, the shaft member 4 is rotated about its central axis. The bicycle is rotated and transmitted to the rear wheels, so that the propulsion of the bicycle is obtained.

The torsion detecting means 7 detects the torsion of the shaft member 4. For example, the torsion angle around the central axis of the shaft member 4 can be determined optically (depending on the amount of light, interference fringes, etc.) or electric / electrical. It is detected magnetically (depending on changes in the capacitance, resistance, magnetic field strength, etc.).

The torque calculating means 8 is provided for calculating the input torque applied to the shaft member 4 from the torsion detected by the torsion detecting means 7, and sends the calculation result to the power control means 9. For example, when the input torque is proportional to the torsion angle around the central axis of the shaft member 4, the input torque can be easily obtained simply by multiplying the torsion angle by a predetermined proportional coefficient.

The power control means 9 is provided for calculating the main power of the moving device 1 or the auxiliary power for the main power from the input torque obtained by the torque calculation means 8 to perform power control. To the power source / auxiliary power source 10. The power source / auxiliary power source 10 includes an engine, a motor, and the like. For example, in the case of an assist bicycle, a motor is an auxiliary power source with respect to a leg force as a main power. Is controlled,
The leg force when the driver depresses the pedal is detected as the input torque to the shaft member 4. In the case of a wheelchair or a trolley with an auxiliary motor, the motor is an auxiliary power source for the arm power as the main power, and the power control means 9 detects the input torque to the shaft member 4 due to the arm power. The motor is controlled based on the input torque.

The method of calculating the auxiliary power amount by the power control means 9 does not matter. This is because the calculation method is various depending on the form of the mobile device 1, and is determined by the purpose of use, the mechanism, and the like of the device.

The torsion detecting means 7 is described in FIG.
As shown in FIG. 1, a first detecting means 12 for detecting a rotational displacement about a central axis of an end 11 on the input side or a portion near the end of the shaft member 4,
And a second detecting means 14 for detecting a rotational displacement around a central axis at an end portion (for example, a gear portion or the like) on the output side or a portion 13 near the end portion, and a detection signal from these is calculated as an angle. The detection signal (rotational displacement is referred to as “θi”) from the first detection means 12 and the detection signal (rotational displacement is referred to as “θ
o ". ), The torsion angle of the shaft member 4 (this is referred to as “Δθ”, “Δθ = θi−θ
o ". ) Is preferably calculated, whereby the input torque can be obtained with high accuracy.

The signal indicating the torsion angle Δθ obtained by the angle calculation means 15 is sent to the torque calculation means 8, and the torque calculation means 8 calculates the input torque from the torsion angle Δθ by proportional calculation.

The first or second detecting means may have any configuration as long as it can detect the deformation of the shaft member 4 around the central axis. Low non-contact detection is preferred.

For example, as shown in FIG. 3, irregularities (for example, irregularities of a gear) are formed on end portions or portions 16 and 17 of the shaft member 4 at predetermined intervals around the rotation center axis of the shaft member 4. (A portion 18 indicated by a black stripe in FIG. 3 is a concave portion, and a portion 19 located between the concave portions is a convex portion), and optical detection for optically detecting the concave and convex portions. A configuration in which the means 20 and 20 'are provided is exemplified. When a reflection type optical sensor is used as the optical detection means, light emitted from a light emitting element such as a light emitting diode is applied to the unevenness of the shaft member 4, and the reflected light is captured by a light receiving element such as a phototransistor. Thus, the deformation of the shaft member 4 around the central axis can be detected with a simple configuration.

When a magnetic detecting means for magnetically detecting the irregularities 18 and 19 is used instead of the optical detecting means 20 and 20 ', for example, an exciting coil and a detecting coil are provided to By detecting a difference in magnetic resistance due to unevenness of the shaft member formed of a magnetic material, deformation of the shaft member around the central axis can be detected.

In addition, instead of the above-mentioned unevenness, a member having a different reflectance (a portion 18 shown by a black streak in FIG. 3 is a portion having a low reflectance, and a portion 19 of a white streak located between the portions has a high reflectance). In the case of employing a configuration in which a shaft is provided with a shaft member or a magnetic detection method, N poles and S poles are alternately magnetized instead of the irregularities. There are various forms such as a configuration in which a magnetic pattern formed on a shaft member is detected by a detection element (a coil, a Hall element, or the like), but is not easily affected by deformation of the shaft member, and changes over time. It is preferable to adopt a configuration with a small number.

FIG. 3 shows an example in which the detecting means 20 and 20 'are arranged around the shaft member 4. On the contrary, the detecting means is attached to the shaft member and provided around the shaft member. It is also possible to adopt a configuration in which a change in the member that has been detected is detected by the detection means to detect a relative rotational displacement of the shaft member.

The optical detecting means 20 includes:
As shown in FIG. 4, a first light detection unit 21 that outputs a detection signal corresponding to the unevenness of the shaft member 4, and a predetermined phase difference (phase difference) with respect to the phase of the detection signal by the first light detection unit 21. (For example, 90 °).
And a second light detecting means 22 arranged in a predetermined positional relationship with respect to the first and second detecting means, and sending detection signals of these light detecting means to the rotation direction detecting means 23 to compare the phases of the two detection signals. Thus, the rotation direction of the shaft member 4 can be detected. That is, when the shaft member 4 rotates clockwise as shown by the arrow C in FIG. 4, the detection signal of the first light detection means 21 is advanced in phase with respect to the detection signal of the second light detection means 22. Conversely, when the shaft member 4 rotates counterclockwise in FIG. 4, the detection signal of the second light detection means 22 advances with respect to the detection signal of the first light detection means 21. Become a phase.

By providing these light detecting means 21 and 22 on the input side of the shaft member 4, rotation can be detected with almost no time delay.

The light detecting means 21 and 22 may of course be replaced by the magnetic detecting means.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a shaft-driven assist bicycle will be described below with reference to FIGS.

The assist bicycle 24 shown in FIG. 5 is provided with a motor 27 as an auxiliary power source for an axle 26 of a rear wheel 25. For example, 3
A phase brushless motor is used, which is controlled by the control unit 28.

The control unit 28 is fixed to a plate 30 attached to a frame 29, and has a lithium ion battery 31, 3, which is a power supply to the motor 27.
Are similarly fixed to the plate 30.
The frame 29 extends obliquely downward and rearward from the head pipe 32 of the bicycle, and a part thereof extends to the axle 26 of the rear wheel 25.

Then, the pedals 33, 33 are depressed to rotate the cranks 34, 34, and as shown in FIG.
After being transmitted to the drive shaft 36 (corresponding to the shaft member 4) by (corresponding to the power conversion unit 5), an orthogonal conversion mechanism 37 using a bevel gear (corresponding to the power conversion unit 6). Thus, the torque is converted into the rotational force of the rear wheel 25.

FIG. 6 schematically shows a configuration of a main part in a cross section of the assist bicycle 24 cut by a plane including the axle 26 of the rear wheel 25 (only one of the pedal 33 and the crank 34 is used). The drive shaft 36 is rotatable around its central axis in a tube 40 spanned between a gear housing 38 containing the orthogonal transforming mechanism 35 and a gear housing 39 containing the orthogonal transforming mechanism 37. It is arranged in a state.

A crankshaft 41 is provided in the gear housing 38.
A bevel gear 42 fixed to the drive shaft 36 is provided, and the bevel gear 42 is meshed with a bevel gear 43 provided at the front end of the drive shaft 36. That is, when the bevel gear 42 is rotated with the rotation of the crankshaft 41, the drive shaft 36 is rotated from the bevel gear 42 via the bevel gear 43 around the central axis.

An optical detecting section 44 corresponding to the optical detecting means 20 is attached to the gear housing 38 with a positional relationship facing the rear end of the bevel gear 42. The input to the drive shaft 36 is controlled by the optical detecting section 44. Side rotational displacement is detected. Incidentally, the unevenness of the gear of the bevel gear 42 corresponds to the unevenness 18 and 19 described above. When the unevenness of the gear is used in this way, it is not necessary to separately provide the detected part of the optical detection unit 44, and the configuration is simplified. Become.

In the gear housing 39, a bevel gear 45 provided at the rear end of the drive shaft 36 is meshed with a bevel gear 46 fixed to the axle 26 of the rear wheel 25, so that the bevel gear 45 rotates with the rotation of the drive shaft 36. 45 is rotated, the force transmitted from the bevel gear 45 through the bevel gear 46 causes the rear wheel 2 to rotate.
5 will be rotated.

An optical detecting section 47 corresponding to the optical detecting means 20 'is attached to the gear housing 39 so as to face the rear end of the bevel gear 45, and the optical detecting section 47 controls the drive shaft 36. The rotational displacement on the output side is detected. It should be noted that the irregularities of the gear of the bevel gear 45 correspond to the irregularities 18 and 19 described above and the advantages thereof have already been described in the description of the optical detection unit 44.

As described above, the torsion angle of the drive shaft 36 can be replaced by the phase difference between the gears of the bevel gears 43 and 45 and optically detected. There is almost no need to change the material and the like.

In the rear wheel 25 shown in FIG.
6 passes through the center of the hub 48 and the rim 5 of the tire 49
The spokes 51 are stretched between the hub 0 and the hub 48. The hub 48 forms a part of the rotor of the motor 27, and is provided with a rotational force by exciting a stator coil (not shown).

FIG. 7 is a block diagram showing the outline of the power system of the assist bicycle 24. The main power (leg force) is transmitted via a drive mechanism 52 (including the orthogonal transform mechanisms 35 and 37 and the drive shaft 36). The power is transmitted to the axle 26 to rotate the rear wheel 25.

The torque detector 53 (including the bevel gears 43 and 45 and the optical detectors 44 and 47) detects the input torque applied to the drive shaft 36 and sends the signal to the controller 54.

The control unit 54 calculates an auxiliary power amount according to the input torque and generates a control signal to the motor 27.

A computer can be used for the input torque calculation processing in the torque detection section 53 and the processing in the control section 54.
When the auxiliary power is proportional to the torsion angle of the motor and the amount of auxiliary power can be obtained from the input torque by a multiplication operation (so as to assist the leg force with a torque equivalent to the input torque, a so-called 1/2 power assist or the like), the torque detector is used. The 53 and the control unit 54 may be configured as a dedicated circuit.

The auxiliary power is directly transmitted to the axle 26 as the torque of the motor 27 and is used as the torque of the rear wheel 25.

FIGS. 8 and 9 show the detection of the torsion angle of the drive shaft 36. FIG. 8 shows the drive shaft and a plurality of sensors. FIG. 9 shows an example of a change in the signal output from each sensor. Is shown.

Two sensors 55 and 56 are provided for the bevel gear 43 at the front end of the drive shaft 36, and constitute the above-described optical detection unit 44. These sensors 55 and 56 output a binarized signal (H (high) / L (low)) according to the unevenness of the teeth of the bevel gear 43, and the phase difference between the output signals is 90 °. The bevel gear 43 is disposed around the rotation center axis at a predetermined angular interval.

A sensor 57 constituting the optical detection section 47 is provided for the bevel gear 45 at the rear end of the drive shaft 36. The sensor 57 is a binary signal corresponding to the unevenness of the teeth of the bevel gear 45. And output the conversion signal.

Incidentally, a reflection type photo sensor is used for the sensors 55 to 57.

In FIG. 9, signal "S55" indicates the output signal of the sensor 55, signal "S56" indicates the output signal of the sensor 56, and signal "S57" indicates the signal of the sensor 5
7 shows the output signal.

The signal example shown is the drive shaft 36
Shows a temporal change of each signal in a state where the signal is rotated in a direction indicated by an arrow A in the figure by the input torque from the stationary state, and the phase of the signal S56 is advanced from the phase of the signal 55.

FIG. 10 shows an example of a circuit configuration relating to the calculation of the input torque. The output signal S55 of the sensor 55 is supplied to the rotation direction detector 59 via the amplifier 58 (corresponding to the rotation direction detector 23). As well as to the terminal (UP) of the counting section 60 (corresponding to the torque calculating means 8).

The output signal S 56 of the sensor 56 is sent to the rotation direction detector 59 via the amplifier 61.

The rotation direction detector 59 includes sensors 55 and 56.
By comparing the phases of the output signals S55 and S56 with each other, a detection signal indicating the rotation direction of the drive shaft 36 according to the degree of progress (this is referred to as “S59”)
It is written. ) Is sent to the terminal (DIR) of the counting section 60.

Then, the output signal S57 of the sensor 57 is sent to the terminal (DW) of the counting section 60 via the amplifier 62.

The counting section 60 counts up the number of pulses of the signal S55 input to the terminal (UP) and counts down the number of pulses of the signal S57 input to the terminal (DW). By performing the operation, the torsion angle of the drive shaft 36 based on the input torque is obtained, and an input torque detection signal proportional to this is output.
Then, the counting section 60 outputs a rotation direction detection signal of the drive shaft 36 according to the detection signal S59 input to the terminal (DIR). Incidentally, instead of separately outputting the information indicating the rotation direction and the input torque value, one signed data can be output by adding a positive or negative sign indicating the rotation direction to the input torque value. .

When the input torque is applied to the drive shaft 36, the bevel gear 43 rotates in the direction indicated by the arrow A in FIG. 8, and the bevel gear 45 is stopped by the load of the wheel (rear wheel) (FIG. 9). During the period “Ta”), the sensor 55,
56 output signals S55 and S56 are obtained as pulse signals (the signal S57 is an L signal), and the signal S5.
By counting the number 5 by the counting section 60, the torsion angle of the drive shaft 36 and the magnitude of the input torque proportional thereto can be determined. At this time, the signals S55 and S5
Since the rotational direction of the bevel gear 43 can be known from the phase relationship with 6, the input torque can be obtained by assigning a positive or negative sign corresponding to the rotational direction to the magnitude of the input torque.

Thereafter, during the period "Tb" shown in FIG. 9, the bevel gear 45 rotates, and the output signal S57 of the sensor 57 is obtained as a pulse signal in response to the rotation, and the counting section 60 counts down by the number of pulses. Therefore, the torque at the time of equilibrium after the torsion of the drive shaft 36 is eliminated can be obtained.

According to the assist bicycle 24,
Since the input torque can be detected based on the torsion angle of the drive shaft 36 constituting the power transmission mechanism from the crank 34 to the rear wheel 25, the configuration of the torque detector 53 is simplified, and the space and cost are reduced. In addition, the weight can be reduced. In addition, by providing the auxiliary power directly to the rear wheel 25 by the motor 27, the rotational force of the motor 27 is transmitted to the rear wheel 25 via the drive shaft 36.
Power transmission mechanism can be simplified as compared with the configuration of transmitting power to the power transmission mechanism.

[0056]

As apparent from the above description, according to the first aspect of the present invention, the torsion of the shaft member is detected, and the input torque applied to the shaft member from the torsion is calculated. Control of main power or auxiliary power can be performed accordingly. Therefore, by detecting the input torque using the shaft member for transmitting the power to the wheels, a space necessary for disposing the torsion detecting means with respect to the shaft member is secured as an arrangement space for the torque detecting means. By doing so, cost reduction and weight reduction can be achieved.

According to the second aspect of the present invention, the torsion angle of the shaft member is calculated from the difference between the detection signals of the detection means provided at the input / output side of the shaft member, and a predetermined proportionality is calculated. By multiplying the coefficient, the input torque can be easily obtained, and the configuration can be simplified.

According to the third aspect of the invention, by detecting the unevenness formed on the shaft member optically or magnetically, the torsion angle of the shaft member is converted into a phase difference relating to the detection of the unevenness, and the The input torque can be reliably obtained, the configuration is simpler than the method of attaching the detection member to the shaft member, and the influence on the rotation of the shaft member is small.

According to the fourth aspect of the present invention, the rotation direction of the shaft member can be easily detected by comparing the detection signals of the two detection means with respect to the progress of their phases.

[Brief description of the drawings]

FIG. 1 is a diagram conceptually showing a basic configuration of an apparatus according to the present invention.

FIG. 2 is a diagram illustrating a method of detecting an input torque applied to a shaft member.

FIG. 3 is an explanatory diagram of a method of detecting twist of the shaft member by optically detecting unevenness formed on the shaft member.

FIG. 4 is a diagram illustrating detection of a rotation direction of a shaft member.

FIG. 5 shows an embodiment of the present invention together with FIGS. 6 to 10, and is a schematic side view of the assisted bicycle.

FIG. 6 is a horizontal sectional view showing a main part of the driving mechanism.

FIG. 7 is a block diagram showing a drive system.

FIG. 8 is a perspective view showing a drive shaft and a sensor.

FIG. 9 is a time chart showing output signals of the sensor of FIG. 8;

FIG. 10 is a block diagram showing a circuit configuration example relating to calculation of input torque applied to a shaft member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Shaft drive type moving device, 2 ... Drive mechanism, 3 ... Wheels, 4 ... Shaft member, 7 ... Torsion detection means, 8 ... Torque calculation means, 9 ... Power control means, 12 ... First detection means,
14 ... second detection means, 15 ... angle calculation means, 16, 1
7 ... ends, 18, 19 ... unevenness, 20, 20 '... optical detection means, 21 ... first light detection means, 22 ... second light detection means, 23 ... rotation direction detection means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naomasa Sato 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Hiroyuki Ito 2--17-22 Akasaka, Minato-ku, Tokyo Akasaka Twin Tower Main Building 15th floor

Claims (4)

[Claims] 1. A shaft-driven moving device provided with a drive mechanism for transmitting power to wheels via a rotating shaft member, comprising: a torsion detecting means for detecting a torsion of the shaft member; and a torsion detecting means for detecting the torsion of the shaft member. Torque calculation means for calculating an input torque applied to the shaft member from the torsion to be applied; and power control for calculating a main power or an auxiliary power for the main power of the moving device from the input torque obtained by the torque calculation means to perform power control. Means for moving the shaft-driven moving device. 2. The shaft-driven moving device according to claim 1, wherein the torsion detecting means detects a rotational displacement of the shaft member at or near an input-side end of the shaft member. Second detection means for detecting the rotational displacement of the shaft member at or near the output end, and a detection signal by the first detection means and a detection signal by the second detection means Angle calculating means for calculating a torsion angle of the shaft member by calculating a difference between the torque calculating means and the torque calculating means, based on the torsion angle obtained by the angle calculating means, calculating an input torque proportional to the torsion angle. Shaft driven moving device. 3. The shaft-driven moving device according to claim 2, wherein the first or second detecting means is formed on the shaft member at predetermined intervals around a rotation center axis of the shaft member; A shaft-driven moving device, comprising: optical detecting means for optically detecting the irregularities or magnetic detecting means for magnetically detecting the irregularities. 4. The shaft-driven moving device according to claim 3, wherein the optical detection means outputs a detection signal corresponding to the unevenness of the shaft member, and the first light detection means. And a second light detecting means arranged in a predetermined positional relationship with respect to the first light detecting means so as to have a predetermined phase difference with respect to the phase of the detection signal obtained by A shaft-driven moving device, comprising: a rotation direction detection unit that detects a rotation direction of a shaft member by comparing a phase of a detection signal of the second light detection unit with a phase of the detection signal of the second light detection unit.