JP2001151184A - Power assisted bicycle and its drive control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a smoothly operable power assisted bicycle. SOLUTION: This bicycle comprises a drive motor M for rotating a rear wheel 43 by battery voltage; a speed sensor for detecting the vehicle speed from a vehicle speed detecting major gear fixed to a crankshaft 17; a torque sensor for detecting the torque from the connecting and disconnecting state of a driving-side cam plate rotated by pedal operating force and fixed to the crankshaft 17 and a driven-side cam plate pressed and energized to the drive-side cam plate by a disc spring and fixed to a chain major gear 18 movable to the crankshaft 17; and a control part 46 for controlling the control system. In this bicycle, the propriety of the control system is checked when an ON switch is ON, the pulse is calculated on the basis of the detection signal from the speed sensor and the detection signal from the torque sensor until and OFF switch is ON when the battery state is proper, the increasing and decreasing control of pulse width is performed according to the relation with a reference value, and the pulse obtained after the control is outputted to control the operation of the drive motor M as long as the bicycle is in a traveling state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the operation of a drive motor based on a power relationship between an input torque applied to a crankshaft by a pedal depression force and a load torque applied from a rear wheel. The present invention relates to an electric assist bicycle capable of accurately applying an auxiliary driving torque obtained from a motor to a rear wheel, and a driving control method thereof.

[0002]

2. Description of the Related Art Electric assisted bicycles have been used by a large number of people in recent years because they can travel with a reduced burden on a driver with the aid of a drive motor. In this case, the operation of the drive motor needs to be accurately controlled based on the power relationship between the input torque applied to the crankshaft and the load torque applied from the rear wheels.

[0003] For this reason, electric assist bicycles are usually provided with a torque detecting mechanism capable of detecting an input torque applied to the crankshaft by a pedal depressing force. As a typical example, a torsion bar is provided by the rotational force of the crankshaft. The torsion bar is subjected to torsional deformation to detect the axial movement amount at the tip of the torsion bar and the relative rotation angle with respect to the crankshaft.

[0004]

However, when the input torque is to be detected by the torsional deformation of the torsion bar, the input torque detecting mechanism and the power transmission mechanism for transmitting the input torque from the crankshaft to the rear wheel are provided. However, it is necessary to arrange them separately as separate systems, and the overall structure becomes complicated, resulting in an increase in cost and also an increase in the size and weight of the entire system.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the prior art, the present invention accurately analyzes input torque from a crankshaft and load torque from a rear wheel under a power transmission mechanism for transmitting input torque from a crankshaft to a rear wheel. It is an object of the present invention to provide an electric assisted bicycle and a drive control method for the same, which can simultaneously detect the cost and reduce the size and weight of the electric assisted bicycle.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object. Among them, an electric assist bicycle (first invention) according to the present invention has a forcible force when a pedal depression force becomes an input torque. A driving force in the axial direction is applied to the driving cam plate by a driving cam plate fixed to the rotating crankshaft and a pair of flat springs interposed with the respective concave surfaces facing each other. A driven cam plate fixed to a chain gear wheel that is urged to rotate and move in the axial direction freely on the side of the crankshaft is fixed to a raised portion provided on the driving cam plate. The concave portion provided on the side cam plate is arranged facing each other so as to freely slide in the rotational direction at a plurality of locations, and as the load torque applied from the rear wheel increases, the driving side cam plate becomes Bump Of the chain large gear that surrounds the outer periphery of the driving side cam plate and the driven side cam plate and that varies with the rotational displacement of the driven side cam plate caused by the A torque sensor, which is disposed at an appropriate position on the inner end face side of the magnetic ring fixed inside to freely detect the magnetic force, is converted into an average value of detection values detected separately and controls operation of the drive motor. In this way, the drive assist torque can be freely applied to the rear wheels, and the chain shaft is mounted on the crankshaft located on the inside of the connected crank on the opposite side in the axial direction from the chain large gear. A vehicle speed detection gear that has substantially the same shape as the gear is fixed on the shaft, and the traveling speed can be freely detected via a speed sensor installed at a position facing the tooth portion of the vehicle speed detection gear. Up There is a feature.

In this case, it is preferable that the pair of flat springs is disposed with an elastic material interposed between the concave surfaces. Further, the magnetic ring is integrally formed by a ring-shaped magnet portion positioned at a portion facing the torque sensor at the time of its rotation, and a resin reinforcing portion covered at a portion except an inner end surface of the magnet portion. The formed one can be suitably used. Further, the displacement of the driving side cam plate with respect to the driven side cam plate is provided by providing a concave engagement portion on the upper surface of the raised portion, and at a starting end side of the concave portion of the driven side cam plate located at a portion facing the concave engagement portion. It is preferable that a hook pin is provided upright, and that the movement of the hook pin can be freely controlled within a stroke from the start end to the end of the concave engagement portion.

On the other hand, a drive control method for an electric assist bicycle according to the present invention (a second invention) includes a rechargeable battery detachably mounted on a frame of the electric assist bicycle, and a voltage applied from the battery. A drive motor arranged to forcibly rotate the rear wheel through a hub, a speed sensor for detecting the vehicle speed of the electric assist bicycle from the rotation state of a vehicle speed detecting large gear directly connected to the crankshaft, and an electric assist. The load torque applied to the bicycle is driven by the driving cam plate fixed to the crankshaft, which is forcibly rotated by the pedaling force as the input torque, and a pair of flat springs inserted with their concave surfaces facing each other. An axial pressing force is applied to the driving cam plate in the axial direction, so that the driving gear is fixed to a chain gear that is rotatably supported on the crankshaft side so as to freely rotate and move in the axial direction. At least a torque sensor that detects from the contact / separation state with the driven cam plate, and a control unit that performs overall control in accordance with the input operation state of various switches of the operation unit. The self-diagnosis of checking the correctness of the control system is performed based on a command from the control unit only when the switch-on is genuine, and if it is normal, the charging status of the attached battery is checked, and the charging is performed. Authentic O if there is no problem in the situation
Until the FF switch is turned on, always measure the speed based on the detection signal from the speed sensor, measure the torque based on the detection signal from the torque sensor, and generate a pulse from the measured speed and torque. The pulse width is gradually increased / decreased in relation to a preset reference value, and a pulse obtained after the control is output to control the operation of the drive motor as long as the electric assist bicycle is in a running operation state. To do it.

In this case, it is desirable to measure the torque based on the average value of the respective detection values obtained from the detection signals separately obtained by the two torque sensors disposed separately.

[0010]

FIG. 1 is an explanatory view schematically showing a schematic configuration example of the present invention. An electric assisted bicycle 11 is rotatable on a hanger rack 16 by a pedaling force F obtained by depressing a pedal 13. An input torque for forcibly rotating the inserted and supported crankshaft 17 via the cranks 14 and 15 is generated, and transmitted from the chain large gear 18 fixed to the crankshaft 17 via the chain 41 and the chain small gear 42. The rear wheels 43 are forcibly rotated by the applied input torque, so that the vehicle can travel manually on a flat road surface R.

When the vehicle starts traveling after operating a predetermined switch of the operation section 38 or when traveling on a slope such as a hill, the vehicle receives power from a battery 44 detachably supported by the frame 12 to receive power. A housing 4 disposed coaxially with the chain pinion 42 of the wheel 43
The drive motor M in 5 is operated, and a drive assist torque is added to the rear wheel 43 by the rotational force of the drive motor M, so that the vehicle can travel easily with the assistance. In addition,
Reference numeral 46 in the figure denotes a control unit separately provided for controlling the operation of the drive motor and performing necessary calculations.

FIG. 2 is a main part configuration diagram showing a power transmission mechanism including the crankshaft 17 shown in FIG. 1 with a part cut away. As shown in FIG. , 15 have bosses 1 at their base ends.
4a and 15a are provided, and these boss portions 14a and
It is fixed to both ends of the crankshaft 17 via 15a. Therefore, the pedaling force F alternately applied from the pedal 13 via the cranks 14 and 15 is transmitted as an input torque to the crankshaft 17 and forcibly rotates the crankshaft 17.

In addition, the boss portion 14 of one crank 14
a is secured by making the length of the crankshaft 17 in the axial direction relatively long, and is mounted on the inner end side of the boss portion 14a so that the driving side cam plate 22 can rotate integrally. Have been. The driven side cam plate 25 is loosely inserted into the outer periphery of the intermediate portion of the boss portion 14a in such a manner that one side surface 22a of the driving side cam plate 22 and one side surface 25a thereof face each other. Further, a screw hole 28 is provided at an appropriate position of the driven side cam plate 25,
Chain gear 18 located at a position facing screw hole 28
The driven side cam plate 25 and the chain large gear 18 are integrated by a screw 31 screwed through a through hole 19 formed in the shaft. For this reason, the driven side cam plate 25 and the chain large gear 18 can move in the axial direction integrally with the crankshaft 17 and are rotatably supported by the shaft.

FIG. 3 shows a state in which the driving side cam plate 22 and the driven side cam plate 25 constituting the power transmission mechanism are separated from each other so that the side faces 22a and 25a facing each other are open. It is a perspective view shown under. According to the figure, one side 2 of the driving side cam plate 22
On the side of 2a, a total of three raised portions 23 are provided at equal intervals in the circumferential direction. In addition, each of the raised portions 23 has a slope 23a which is gradually inclined forward in the rotation direction of the driving side cam plate 22, and a slope 23a.
A ridgeline 23b is formed at the end of the groove, and a slope 23c that is inclined forward and downward is formed in a mountain shape.

Further, from the slope 23a to the ridge line 23b of any one of the raised portions 23, a bottomed bottom having a substantially elliptical notch shape slightly curved along the outer peripheral portion in the rotation direction of the driving side cam plate 22 is provided. A concave engagement portion 24 is formed. In addition, the concave engagement portion 24 may be a long hole with a bottom, a long hole formed in substantially the same shape as the long hole with a bottom,
It can also be formed by a cutout formed in the inner periphery.

On the other hand, one side 2 of the driving side cam plate 22
On one side surface 25a of the driven side cam plate 25 facing the side 2a, a valley shape having a cross-sectional shape matching the raised portions 23 of the driving side cam plate 22 is formed.
A plurality of recesses 26 are provided.

Further, the starting end 2 of the concave portion 26 in a positional relationship facing the raised portion 23 provided with the concave engaging portion 24.
On the 6a side, a retaining pin 27 having a length and a thickness that fits in the concave retaining portion 24 is provided upright.

Further, as shown in FIG. 2, a pair of flat springs 29, 29 is provided between a flange 20 provided on the outer end side of the boss portion 14a of the crank 14 and the chain large gear 18.
Are inserted in such a manner that their concave surfaces face each other, so that the chain large gear 18 and the driven side cam plate 25 can always be pressed and urged toward the drive side cam plate 22 side. Has become. In this case, it is preferable that an elastic member 30 made of a rubber material or a soft resin material is interposed between the concave surfaces of the pair of flat springs 29, 29. In addition, the flat springs 29, 29
0 is covered with a dustproof rubber cover 36 attached between the peripheral end of the chain gear 0 and the outer surface of the chain large gear 18.

On the inner surface of the chain gear 18,
A magnetic ring 32 disposed so as to cover the driving side cam plate 22 and the driven side cam plate 25 from the outer peripheral side thereof is fixed. The magnetic ring 32 includes a ring-shaped magnet portion 33 made of, for example, a rubber magnet or a ferrite magnet, and a disk-shaped reinforcing resin portion 34 that exposes an inner end surface 33 a of the magnet portion 33 and covers the whole. And those formed by the above can be preferably used. However, if necessary, a magnetic ring formed of a metal magnetic ring (not shown) can be used. Further, at appropriate two locations facing the inner end surface 33a of the magnet portion 33, one upper and lower locations in the illustrated example, a torque sensor 39 capable of detecting magnetic force is supported by, for example, a sensor cover 39a. And are arranged close to each other. Therefore,
These torque sensors 39 detect the distance between the inner end surface 33a of the magnet portion 33 based on the average value of the detection values detected separately, that is, the load torque at each time is detected via a magnetic circuit separately prepared. I can do it.

In addition, a crankshaft 17 located inside the boss 15a of the crank 15 connected to the opposite side to the chain gear 18 has a vehicle speed detecting shape which has substantially the same shape as the chain gear 18. A large gear 37 is fixed to the shaft, and the traveling speed can be detected via a speed sensor 35 such as a photo sensor or a magnetic sensor disposed in proximity to a portion of the large gear 37 for vehicle speed detection facing the tooth portion 37a. It has become.

In this case, the respective detection signals obtained from the torque sensor 39 and the speed sensor 35 are individually sent to a control unit 46, calculated by the control unit 46, and the input torque applied to the crankshaft 17 It is used as data for calculating a combined torque or a vehicle speed generated between the load torque and the load torque applied from the rear wheels 43.

Next, an example of the method of the present invention (second invention) will be described together with the operation of the electric assisted bicycle 11 having the above-described structure of the first invention.

FIG. 5 is a block diagram showing an example of the operation control system of the drive motor, and FIG. 6 is a flowchart showing an example of the processing steps of the method of the present invention.

According to these figures and FIG. 1, the battery-assisted bicycle 11 has a chargeable battery 44 and a drive motor M operated by the battery 44 as described above.
, A speed sensor 35 for detecting a vehicle speed, a torque sensor 39 for detecting a load torque, and a control unit 46 for integrally controlling the whole of the switches according to the operation states of various switches in the operation unit 38.

The method of the present invention applied to the electric assisted bicycle 11 is implemented by a control system based on a command from the control unit 46 only when the ON switch from the operation unit 38 is genuine. A self-diagnosis is performed to check for correctness. If normal, the charging status of the attached battery 44 is checked. If there is no problem in the charging status, the speed sensor is constantly checked until a genuine OFF switch is turned on. The speed is measured based on the detection signal from the torque sensor 35, the torque is measured based on the detection signal from the torque sensor 39, a pulse is calculated from the speed and the torque, and a pulse is calculated based on a relationship with a preset reference value. Pulse width increasing / decreasing control is performed, a pulse obtained after the control is output, and the driving mode is set as long as the battery-assisted bicycle 11 is in a running operation state. It is performed by controlling the operation of the M.

That is, the electric assist bicycle 1
When the ON switch is turned on from the first operation unit 38, for example, it is determined whether or not the button is pressed for 2 seconds or more.
Assuming that the switch is turned on, a self-diagnosis is performed to automatically check the suitability of the control system based on a command from the control unit 46. If it is determined as a result of the self-diagnosis that an error has occurred, an error is displayed by, for example, turning on an LED provided on the operation unit 38.

As a result of the self-diagnosis, if there is no abnormality in the control system of the battery-assisted bicycle 11, the voltage of the battery 44 mounted on the frame 12 is checked. The driver is notified by lighting the LED of the unit 38 or the like.

On the other hand, if there is no problem in the charging status of the battery 44, the speed sensor is kept on until the genuine OFF switch is turned on from the operation unit 38 (for example, the OFF switch is turned on for one second or more). A speed measurement according to 35 is performed.

Specifically, a pedaling force F obtained by starting operation and alternately depressing the pedal 13 is transmitted as an input torque to the crankshaft 17 via the cranks 14 and 15, and is transmitted to the boss portion 14a. , 15a and the crankshaft 17 integrated with the drive side cam plate 22
To forcibly rotate.

The crankshaft 17 has a large gear 3 for detecting vehicle speed.
Since the shaft 7 is fixed, the large gear 37 for detecting the vehicle speed is also rotated, and the speed sensor 35 accurately detects the passing state of the individual teeth 37a, and the speed is measured based on the detection signal. become. That is, a detection signal corresponding to the number of the teeth 18a passing within a predetermined time set in advance can be sent to the control unit 46, and the control unit 46 determines the number of the teeth 18a passed from the crankshaft 17 ( The rotational speed of the chain large gear 18) is calculated, and the vehicle speed of the battery-assisted bicycle 11 is calculated from the gear ratio and the diameter of the rear wheel 43. In addition, since the load torque unlike the chain large gear 18 is not applied to the vehicle speed detecting large gear 37, the rotation speed can be accurately detected with little vibration during rotation.

On the other hand, the pedaling force F obtained by alternately depressing the pedal 13 becomes an input torque via the cranks 14 and 15 and is transmitted from the crankshaft 17 to the large chain gear 18. At this time, since the driven side cam plate 25 is pressed and biased toward the drive side cam plate 22 together with the chain large gear 18 by the flat springs 29, 29, a load applied to the chain large gear 18 is applied to the flat springs 29, 29. When the pressure is smaller than the pressing force, FIG.
As shown in (a), the drive-side cam plate 22 and the driven-side cam plate 25 are brought into close contact with each other in a state in which the raised portion 23 and the recessed portion 26 are fitted to each other. I have.

In this state, the rotational motion of the driving cam plate 22 is transmitted to the driven cam plate 25 as it is by the frictional force generated between the driving cam plate 22 and the driven cam plate 25. Then, by forcibly rotating the chain large gear 18 directly connected to the driven cam plate 25, a rotational force can be applied to the rear wheel 43 via the chain 41 and the chain small gear 42.

On the other hand, when the electric assist bicycle 11 starts running, or when the bicycle is approaching a hill, the rear wheels 4 are not used.
When a large load is applied to 3, the load torque generated at that time is transmitted from the large chain gear 18 to the driven cam plate 25 via the small chain gear 42 and the chain 41.

That is, since the driven side cam plate 25 is braked to stop its rotation by the load torque, the driven side cam plate 25 and the driven side cam plate 22 still rotating by the input torque obtained from the pedal 13 Generate forces acting in opposite directions, causing mutual displacement.

As described above, the displacement between the driving side cam plate 22 and the driven side cam plate 25 is caused by the raised portion 23 of the driving side cam plate 22 being driven by the driven side cam plate 2.
5, which acts as a force to escape from the concave portion 26, and presses the concave portion 26 in the direction of inclination of the slope 23a.
Is pushed outwardly along the axial direction of the boss 14a of the crank 14 while resisting the pressing force of the flat springs 29, 29.

In addition, the displacement between the driving side cam plate 22 and the driven side cam plate 25 is caused by the displacement of the pedal 1.
The movement is stopped at the equilibrium point between the input torque from the third wheel and the load torque from the rear wheel 43. Therefore, by measuring the amount of movement of the driven side cam plate 25 along the axial direction of the boss portion 14 a at that time, a difference between the input torque applied to the crankshaft 17 and the load torque applied from the rear wheels 43 is generated. The magnitude of the resultant torque to be obtained is required.

More specifically, the distance between the magnetic ring 32 fixed to the chain large gear 18 and the inner end face 33a of the magnet portion 33 can be detected by the magnetic circuit using the torque sensor 39. Therefore, when the load torque is zero, in the distance t ₁ as shown in FIG. 4 (b),
When the load torque is generated, if the separation distance t ₂ is assumed as shown in FIG.
The amount of movement of the (chain large gear 18) in the axial direction is t ₂ -t
_It becomes ₁ and the resultant torque is also proportional to this. Therefore, by calculating the detection value obtained from the torque sensor 39 via the control unit 46, the magnitude of the combined torque can be calculated.

The driven side cam plate 25 is constantly pressed against the driving side cam plate 22 via the flat springs 29, 29, so that the driven side cam plate 22
The rotation of the drive side cam plate 22 is transmitted to the driven side cam plate 25 in a state where the input torque applied to the driven side and the load torque applied to the driven side cam plate 25 are balanced. Therefore, the chain large gear 18 fixed to the driven cam plate 25 also rotates, and the rear wheel 43 is driven to rotate via the chain 41. In the case where the elastic member 30 is interposed between the concave surfaces of the pair of flat springs 29, 29, when the pressing force is released, a more secure restoring force is applied so that the flat spring 29 has its original shape. Can be returned automatically.

Further, as shown in FIG.
The torque sensors 39 are provided at two places facing the inner end face 33a of
Are arranged close to each other, even if the magnetic ring 32 oscillates during its rotation, the torque sensor 39 and the inner end surface 33a of the magnet part 33 are based on the average value of the detection values separately detected by the torque sensors 39. By accurately detecting the separation distance therebetween, the load torque at that time can be accurately detected via a separately prepared magnetic circuit. That is, when the load torque is zero, in the distance t ₁ and t ₂ as shown in FIG. 4 (a), when the load torque occurs, FIG. 4
If a distance t ₃ and t ₄ as shown in (b), the moving amount in the axial direction of the driven side cam plate 25 (chain gear wheel 18) is t ₃ -t ₁ and t ₂ -t ₄ By calculating the average value through the control unit 46, the magnitude of the combined torque can be more accurately calculated.

The control section 46 calculates a pulse from the vehicle speed and the resultant torque calculated in this manner, and controls the pulse width to be gradually increased / decreased in relation to a preset reference value, that is, pulse width modulation (pulse width modulation). PWM) control, and outputs a pulse obtained after the control to apply a predetermined drive assist torque to the rear wheels 43 while appropriately controlling the operation of the drive motor M as long as the electric assist bicycle 11 is in a running operation state. I do. As a result, the rear wheels 43 are driven by the input torque obtained by depressing the pedal 13 and the drive assist torque obtained by the drive motor M, and as a result, the vehicle runs lightly in an optimal state according to the situation at that time. Can be.

Further, the driving side cam plate 22 has a recessed engaging portion 24 on one of the raised portions 23 provided on one side surface 22a thereof, and the driven side cam plate 25 has one side surface 25a thereof. Recessed part 2 provided in
6 can be provided with a locking pin 27, respectively.

Therefore, in this case, the driving side cam plate 22 and the driven side cam plate 25 are connected to the concave engagement portion 2.
By positioning the latching pins 27 in the inner surface 4 and making them face-to-face with each other, the sliding of the driving side cam plate 22 is moved to the extent that the latching pins 27 move from the starting end 24a of the concave engaging portion 24 to the end 24b. Can be regulated.

For this reason, for example, even if an unexpected load torque is applied, it is possible to prevent the raised portion 23 from going over the concave portion 26 and to rotate the chain large gear 18 reversely on a downhill or the like. However, generation of load torque can be prevented. Also, when the chain large gear 18 is inadvertently rotated reversely when the electric assist bicycle 11 stops, a load torque is generated to operate the drive motor M, and the rear assist wheel 43 rotates naturally by the drive assist torque at that time. Also, it is possible to prevent an unexpected accident such as running the electric assist bicycle 11 out of control.

Further, the electric assist bicycle 11 according to the present invention.
In, the input torque applied to the crankshaft 17 and the load torque applied from the rear wheels 43 can be detected as a combined torque. Therefore, the detection of the combined torque and the transmission of the power to the rear wheels 43 can be performed through the same power transmission mechanism, so that the overall structure can be simplified, and the cost reduction and the reduction in weight and size can be realized.

In FIG. 6, the state of charge of the battery 44 is checked after the self-diagnosis of the control system by the control unit 46. However, after the state of charge of the battery 44 is checked, Self-diagnosis of the correctness of the system may be performed.

[0046]

As described above, according to the first aspect of the present invention, the raised portion of the driving side cam plate and the recessed portion of the driven side cam plate are slidably fitted in the rotating direction. Since a torque sensor is provided for detecting the positional displacement in the rotational direction by sliding the ridge side as the load torque applied from the rear wheel increases, the input applied to the crankshaft. It is possible to provide an electric assist bicycle including a simplified power transmission mechanism capable of simultaneously detecting a torque and a load torque applied from a rear wheel as a combined torque. Therefore, not only can the product cost of the electric assisted bicycle be reduced, but also the weight and size can be reduced.

In this case, if an elastic material is interposed between the concave surfaces of the pair of flat springs, a more stable restoring force is applied when the pressing force is released to automatically return the flat spring to its original shape. Can be done. When the magnetic ring is formed integrally with the magnet part and the resin reinforcement part, the torque sensor can be composed of only the magnetic sensor, and the material cost can be reduced, which is effective in reducing the overall cost. Can be contributed. Further, when the driving side cam plate and the driven side cam plate are formed such that the locking pin set up in the concave portion enters into the concave engaging portion provided in the raised portion, the driving side cam plate slides. Even if it moves, the movement can be restricted to the limit from the stroke from the beginning to the end of the concave engaging portion. For this reason, even if unexpected load torque is applied, the chain gear is reversely rotated on a downhill, etc. And accidents can be prevented from occurring.

On the other hand, according to the second invention, the speed is always measured based on the detection signal from the speed sensor, and the torque is measured based on the detection signal from the torque sensor. Calculate the width, perform gradual increase / decrease control of the pulse width in relation to a preset reference value, and output a pulse obtained after the control, so that the drive motor is driven as long as the electric assist bicycle is in the running operation state. Can be controlled, so that the vehicle can run lightly under an optimal condition according to the situation at that time. In addition, the speed sensor can detect the number of rotations not from the chain gear that swings at the time of rotation due to the load torque but from the separately provided gear gear for vehicle speed detection, so that a more accurate vehicle speed can be measured. . In the case where the torque is measured based on the average value of the detection values obtained from the two separately arranged torque sensors, the magnitude of the combined torque can be calculated more accurately, and the torque can be reduced in a more excellent state. Can be run.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a schematic configuration example of an electric assist bicycle according to the present invention.

FIG. 2 is a main part configuration diagram showing a detail of a power transmission mechanism including a crankshaft in FIG. 1 with a part cut away.

FIG. 3 is a perspective view showing the driving-side cam plate and the driven-side cam plate constituting the power transmission mechanism in FIG. 2 in a state where the driving side cam plate and the driven side cam plate are separated from each other so as to be spread;

FIG. 4 is an explanatory diagram showing a non-load state of the power transmission mechanism in FIG. 2 as (A) and a state when a load occurs on the driven side as (B).

FIG. 5 is a block diagram showing an example of an operation control system of a drive motor according to the present invention.

FIG. 6 is a flowchart illustrating an example of processing steps of an electric motor drive control method for an electric assist bicycle according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Electric assisted bicycle 12 Frame 13 Pedal 14, 15 Crank 14a, 15a Boss 16 Hanger rack 17 Crankshaft 18 Chain large gear 18a Teeth 19 Through hole 20 Flange 22 Motor side cam plate 22a One side surface 23 Ridge 23a Slope 23b Ridge 23c Slope 24 Depressed engagement portion 24a Start end 24b Termination 25 Follower cam plate 25a One side surface 26 Recessed portion 26a Start end 27 Hook pin 28 Screw hole 29 Flat spring 30 Elastic material 31 Screw 32 Magnetic ring 33 Magnet portion 33a Inner end surface 34 Resin Part 35 Speed sensor 36 Dustproof rubber cover 37 Large gear for vehicle speed detection 37a Tooth part 38 Operation part 39 Torque sensor 39a Sensor cover 41 Chain 42 Chain small gear 43 Rear wheel 44 Battery 45 Housing 46 Control unit F Treading force R Road surface M Drive motor

Claims (6)

[Claims] 1. The engine according to claim 1, wherein the driving force is generated by a driving cam plate fixed to a crankshaft that is forcibly rotated by a pedaling force as an input torque, and a pair of flat springs interposed with respective concave surfaces facing each other. A driven cam plate fixed to a chain large gear that is axially supported by the pressing force in the axial direction toward the side cam plate to be rotatably supported on the crankshaft side for rotation and axial movement; The raised portion provided on the driving side cam plate and the recessed portion provided on the driven side cam plate are arranged face-to-face so as to freely fit in a rotational direction at a plurality of locations, and from the rear wheel. As the applied load torque increases, the protruding portion side of the driving side cam plate slides, and the separation distance that fluctuates due to the displacement in the rotation direction generated on the driven side cam plate is:
A torque sensor disposed so as to freely detect magnetic force at two appropriate positions on the inner end face side of a magnetic ring fixed to the inside of the chain large gear so as to surround the outer periphery of the driving side cam plate and the driven side cam plate. Is converted to an average value of the detection values detected separately, and by controlling the operation of the drive motor, the drive assist torque can be freely applied to the rear wheel, and the opposite side in the axial direction from the chain large gear. On the crankshaft located inside the connected and connected crank, a gear wheel for detecting vehicle speed, which has substantially the same shape as the chain gearwheel, is fixed, and is opposed to the tooth portion of the gearwheel for detecting vehicle speed. An electric assisted bicycle characterized in that running speed can be freely detected via a speed sensor installed at a site. 2. The pair of flat springs are disposed with an elastic material interposed between the concave surfaces.
The electric assisted bicycle described. 3. The magnetic ring includes an annular magnet portion positioned at a portion facing the torque sensor when the magnetic ring rotates, and a resin reinforcing portion covered at a portion excluding an inner end surface of the magnet portion. The electric assisted bicycle according to claim 1 or 2, wherein the electric assisted bicycle is formed integrally. 4. The displacement of the driving-side cam plate with respect to the driven-side cam plate can be achieved by providing a concave engagement portion on the upper surface of the raised portion, and a concave portion of the driven-side cam plate located at a position facing the concave engagement portion. 4. A hanging pin is provided upright on the starting end side, and the movement of the hanging pin can be freely restricted within a stroke from the starting end to the end of the concave engaging portion. The electric assisted bicycle according to 1. 5. A rechargeable battery removably mounted on a frame of the battery-assisted bicycle, and a drive motor arranged to forcibly rotate a rear wheel via a hub under a voltage applied from the battery. And a speed sensor that detects the vehicle speed of the electric assist bicycle from the rotation state of the vehicle speed detecting large gear directly connected to the crankshaft, and forcibly rotates the load torque applied to the electric assist bicycle with the pedaling force as the input torque. The driving force in the axial direction toward the driving side cam plate is urged by a driving side cam plate fixed to the crankshaft and a pair of flat springs inserted with the respective concave surfaces facing each other. A torque sensor for detecting from a contact / separation state between a driven side cam plate fixed to a chain gear wheel whose rotation and axial movement are freely supported on the crankshaft side; A control unit that performs overall control according to the input operation status of various switches of the operation unit, and receives a command from the control unit only when the ON switch input from the operation unit is genuine. A self-diagnosis is performed to check whether the control system is correct or not, and if it is normal, the charging status of the installed battery is checked. If there is no problem with the charging status, the genuine OFF switch is always turned on until it is turned on. , Measures the speed based on the detection signal from the speed sensor, measures the torque based on the detection signal from the torque sensor, calculates the pulse from the measured speed and torque, and sets a predetermined reference. The pulse width is gradually increased / decreased in relation to the value, and a pulse obtained after the control is output, and the electric assist bicycle is in a running operation state. Drive control method for motor-assisted bicycle, which comprises carrying out by controlling the operation of the drive motor Ri. 6. The electric motor according to claim 5, wherein the torque is measured based on an average value of respective detection values obtained from detection signals respectively obtained by two separately arranged torque sensors. Drive control method for assistive bicycle.