JPH08133167A - Bicycle with electric motor - Google Patents

Abstract

PURPOSE: To suppress racing a pedal by interposing between pedal/motor side drive shafts rotating a side gear of a differential gear device a rotation stop means of regulating relative rotation exceeding a prescribed range between both the drive shafts, so as to regulate transmitting an output of a pedal drive system to a motor. CONSTITUTION: Respectively in a pedal/motor side drive shaft 13, 15, a side gear 35 of constituting a differential gear device 16 is mounted, to mesh each side gear 35 with a pinion gear 36 arranged in a case 30. While absorbing a delicate differential rotational speed between the pedal/motor side drive shafts 13, 15 due to a control delay by rotating the pinion gear 36, the case 30 is rotated, to transmit its rotation to a rear wheel 4. Here are provided protrusions 51, 52 mutually engageably with an end face of the drive shafts 13, 15. At motor starting time with rotation not rising and at battery weak time, both the protrusions 51, 52 are united so that the motor side drive shaft 15 follows rotating the pedal side drive shaft 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bicycle with an electric motor, which assists the pedaling force with the driving force of an electric motor.

[0002]

2. Description of the Related Art In a bicycle with an electric motor, the output of a pedal drive system and the output of a motor drive system are combined by a force combiner to be transmitted to a rear wheel. The form is used. For example, Japanese Unexamined Patent Publication No. 5-58379 includes a resultant shaft having a large bevel gear, and transmits the output of a pedal drive system to the resultant shaft via the gearbox and the large bevel gear.
The one in which the output of the motor drive system is transmitted via the reduction gear and the large bevel gear is described.
Japanese Patent No. 244496 discloses an auxiliary sprocket that is pressed against the tension side of a chain that rotates by human power, and that transmits the output of a motor drive system to the auxiliary sprocket via a gear mechanism.

By the way, in this type of bicycle, the motor is driven according to the output of the pedal drive system so that the force distribution between the pedal drive system and the motor drive system becomes a predetermined ratio (usually 1: 1). It controls the output of the system. However, according to the electric motor-operated bicycle described in the above publications, since the resultant device is composed of a simple gear mechanism, the load on the pedal drive system increases due to the control delay of the motor drive system, Alternatively, when the motor drive system fails, there is a problem that the resultant device locks and suddenly brakes.

Therefore, in Japanese Patent Application No. 6-85995, a differential gear device is used as a resultant device and the differential of the differential gear device is utilized to absorb the control delay of the motor drive system and to drive the motor. A bicycle with an electric motor has been proposed (unknown) in which a lock caused by a system failure is eliminated.

[0005]

However, according to the new bicycle with an electric motor using the above-mentioned differential gear device as a resultant device, the pedal drive system is used at the time of starting the motor when the rotation of the motor does not increase or when the battery goes up. There is a risk that the output of the above will be transmitted to the motor through the rotation of the pinion gear of the differential gear device, the motor will rotate in the reverse direction, and the pedal will idle.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a bicycle with an electric motor using a differential gear device as a resultant device, in which the output of a pedal drive system is a differential gear. It is to restrict the transmission to the motor through the device, and thereby suppress the idle rotation of the pedal.

[0007]

In order to achieve the above object, the present invention is directed to the output of a pedal drive system and the output of a motor drive system, which are combined by a differential gear device to be transmitted to a rear wheel, and the pedal drive system. In an electric motor-powered bicycle in which the output of a motor drive system is controlled according to the output of the system, a predetermined value is provided between a pedal-side drive shaft that rotates a side gear of the differential gear device and a motor-side drive shaft. It is characterized in that a rotation stopping means for restricting relative rotation beyond the range is interposed.

In addition to the above structure, the present invention can further comprise control means for controlling the rotation speed of the motor side drive shaft based on the rotation speed of the pedal side drive shaft.

[0009]

In the electric motor-equipped bicycle constructed as described above, when a large rotation difference occurs between the pedal-side drive shaft and the motor-side drive shaft at the time of starting the motor, when the battery is exhausted, etc., the relative rotation of both drive shafts will occur. The motor-side drive shaft follows the rotation of the pedal-side drive shaft by being restricted by the rotation stopping means, and the motor does not reversely rotate.

When the control means for controlling the rotation speed of the motor side drive shaft based on the rotation speed of the pedal side drive shaft is provided, the rotation speed of the motor side drive shaft is temporarily increased by the control means. It is possible to generate a difference in the number of rotations with the side drive shaft and return both drive shafts to a mutually rotatable state.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 8 shows the entire structure of a bicycle with an electric motor according to the present invention. In the figure, 1 is a main frame, 2 is a front wheel operably supported on a front portion of the main frame 1 by a handle 3, 4 is a sub-frame 5 extending from the main frame 1, and a power transmission mechanism 10 to be described later is provided. A rear wheel supported through the saddle 6, a saddle 6 supported at the center of the main frame 1, and a saddle 6
A crank with a pedal 8 arranged below the
Is a chain transmission mechanism that transmits the rotation of the crank 7 to one end side of the power transmission mechanism 10, and 11 is the power transmission mechanism 1
It is a motor (electric motor) that generates a driving force transmitted to the other end side of 0.

As shown in FIGS. 1 and 2, the power transmission mechanism 10 includes a pedal-side drive shaft 13 that receives rotation of the crank 7 via the chain transmission mechanism 9 and the first power transmission member 12, and a motor 11. The motor-side drive shaft 15 that receives the rotation of the drive shaft 14 via the second power transmission member 14 and the differential gear device 16 that combines the forces transmitted from the drive shafts 13 and 15 and transmits the resultant force to the rear wheel 4. It is configured. The pedal-side drive shaft 13 and the motor-side drive shaft 15 are arranged on the axis of the rear wheel 4, and each of the first and second power transmission members 1 is provided.
It is non-rotatably connected (spline connection in this case) to 2 and 14. The drive shafts 13 and 15 have the same diameter.

The first power transmission member 12 is mounted on a first support shaft 18 which is screwed into a support cylinder 5a which is integral with the subframe 5 on the right side of the vehicle and is fixed with a nut 17a.
It is rotatably fitted through 9. A sprocket 20 is fitted to the first power transmission member 12,
A chain 22 extending from a sprocket 21 (FIG. 2) fixed to the crank 7 is hung on the sprocket 20. The first power transmission member 12, the sprockets 20, 21 and the chain 22 constitute the chain transmission mechanism 9, and the rotation of the crank 7 is transmitted to the pedal side drive shaft 13 via the chain transmission mechanism 9. It has become so.

The second power transmission member 14 is mounted on a second support shaft 23, which is screwed into a support cylinder 5b integral with the subframe 5 on the left side of the vehicle and fixed with a nut 17b, through a bearing 24. Is rotatably fitted. The second power transmission member 14 has a cup shape as a whole, and a pulley (timing pulley) 25 is integrally formed on the outer peripheral surface of a cylindrical portion 14a having a large diameter. A belt (timing belt) 27 extended from a pulley 26 fixed to the output shaft of the. The second power transmission member 14, the pulleys 25 and 26, and the belt 27 constitute a speed reduction mechanism 28, and the motor-side drive shaft 1
The rotation of the motor 11 is transmitted to the motor 5 through the speed reduction mechanism 28.

On the other hand, the differential gear unit 16 is a cup-shaped second gear.
As shown in FIG. 1, both ends of the case (differential case) 30 are arranged in the power transmission member 14 of the first
Bearings 31 on the power transmission shaft 12 and the second power transmission shaft 14
It is rotatably supported via a and 31b. The differential case 30 includes a case main body 32 and a lid 34 attached to the open end of the case main body 32 via bolts 33. The lid 34 has the second power transmission member 14 attached thereto.
The open end of the is fitted through a bearing 31c. A pair of side gears 35 and a pair of pinion gears 36 are arranged in the differential case 30 so as to mesh with each other. The pair of side gears 35 includes the pedal-side drive shaft 13
And the motor-side drive shaft 15 are non-rotatably coupled (spline-coupled) to each other, while the pinion gears 36 are planted on the inner surface of the case body 32 so as to extend in a direction orthogonal to the axis of the rear wheel 4. It is rotatably attached to 37.

Here, the rear wheel 4 is attached to the lid 34 of the differential case 30 using bolts 38. As shown in FIG. 2, the rear wheel 4 includes the differential case 30.
The disc mounting portion 39 is configured as a bottomed tubular disc portion 39, and the disc portion 39 and the tire 40 are connected by a ring portion 41 having a triangular cross section. Also,
A wheel case 42 that supports the motor 11 is attached to the support cylinder 5b that supports the second support shaft 23. The wheel case 42 has a bottomed tubular shape and is loosely fitted in the disc portion 39 of the rear wheel 4. As a result, the entire power transmission mechanism 10 has the disk portion 39 of the wheel.
It is isolated from the outside by the wheel case 42 and is protected from wind and rain, earth and sand, and the like.

A rotation sensor (pedal-side rotation sensor) 43 for detecting the number of rotations of the pedal-side drive shaft 13 is attached to the sub-frame 5 on the right side of the boarding, while the sub-frame 5 on the left side of the boarding (wheels in this case). A rotation sensor (motor-side rotation sensor) 44 that detects the number of rotations of the motor-side drive shaft 15 is attached to the case 42) via a bracket 45. The pedal-side rotation sensor 43 and the motor-side rotation sensor 44 are arranged so as to face a flange 46 integrally formed on the first power transmission member 12 and a flange 47 integrally formed on the second power transmission member 14, respectively. Both rotation sensors 43 and 44 indirectly detect the number of rotations of the drive shafts 13 and 15 via the flanges 46 and 47. The signals of these rotation sensors 43 and 44 are sent to a controller (control means) 48 as shown in FIG. The controller 48 uses the pedal-side drive shaft 1
3 and the motor-side drive shaft 15 have a function of performing feedback control of the number of rotations of the motor 11 based on a signal from the pedal-side rotation sensor 43 so that the number of rotations becomes a predetermined ratio (usually 1: 1). are doing.

In the electric motor-equipped bicycle equipped with the differential gear unit 16, when the pedal 8 is depressed to rotate the crank 7, the rotational speed (rotational speed) S of the drive shaft 13 is increased.
When t is detected by the pedal side rotation sensor 43, the controller 48 takes in the number of rotations St, and normally, the number of rotations of the motor 11, that is, the drive shaft 15 thereof, is obtained so that the same number of rotations can be obtained by the motor side drive shaft 15. Control. As a result, both drive shafts 13 and 15 rotate in the same direction at the same rotational speed, the pinion gear 36 in the differential gear device 16 does not rotate, and the differential case 30 rotates at the same rotational speed as both drive shafts 13 and 15. Then, the rotation is transmitted to the rear wheel 4.
The rotation speed Sm of the motor-side drive shaft 15 is calculated by the rotation sensor 4
The controller 48 performs feedback control of the rotation of the motor 11 based on the signal from the rotation sensor 44.

By the way, according to the above-mentioned same speed control system, there is a control delay from when the pedal-side drive shaft 13 reaches a certain rotation speed St to when the motor-side drive shaft 15 reaches the rotation speed St. Due to the delay, a slight rotational speed difference occurs between the pedal-side drive shaft 13 and the motor-side drive shaft 15. However, this rotation speed difference is absorbed by the rotation of the pinion gear 36, that is, by the differential of the differential gear device 16, and therefore the load on the pedal drive system is not increased. Even when the motor 11 or the speed reduction mechanism 28 stops operating for some reason, for example, a rotational speed difference occurs between the pedal-side drive shaft 13 and the motor-side drive shaft 15, but in this case as well, the pinion gear is the same as described above. 36 rotates, the differential case 30 rotates, and the rotation of the rear wheel 4 is continued.

By the way, for example, at the time of starting the motor in which the rotation of the motor 11 does not increase or when the battery goes up, the drive shaft 15 on the motor side does not function as a reaction force receiving member.
The motor-side drive shaft 15 rotates in the opposite direction to the pedal-side drive shaft 13 in response to the rotation of the pinion gear 36, and the rotation of the pinion gear 36 rotates in the second direction.
1 via the power transmission member 14 and the belt 27 of
1 is transmitted to the motor 11, and the motor 11 rotates in the reverse direction. When such a phenomenon occurs, it goes without saying that the rotation of the pedal side drive shaft 13 is not transmitted to the rear wheel 4 and the pedal 8 runs idle.

Therefore, in this embodiment, as well shown in FIGS. 1 and 3, the pedal-side drive shaft 13 and the motor-side drive shaft 15 inserted into the differential gear unit 16 are respectively provided with insertion ends. Protrusions (rotation stopping means) 51 and 52 which can be engaged with each other are provided. Each protrusion 51, 52 has a trapezoid of the same size, and the corresponding drive shaft 13, 15
Is provided so as to be offset toward the peripheral edge side. As a result, when the pedal-side drive shaft 13 and the motor-side drive 15 are rotated relative to each other, the protrusions 51 and 52 on the drive shafts are brought into contact with the respective side surfaces 51a and 52a to be united, and the force is large. The other drive shaft follows the rotation of the other drive shaft.

In the electric motor-operated bicycle constructed as described above, the pinion gear 36 rotates in response to the rotation of the pedal drive shaft 13 at the time of starting the motor when the rotation of the motor 11 does not increase or when the battery goes up, and drives the motor. The shaft 15 rotates in the reverse direction. Then, as described above, the protrusions 51 and 52 provided on both drive shafts 13 and 15 are united during the rotation, and as a result, the rotation of the pedal-side drive shaft 13 passes through the pinion gear 36 and the pinion shaft 37 and the differential case 3 is rotated.
0 is transmitted to the rear wheel 4. That is,
The pedal 8 only idles slightly at the beginning of starting, and the pedaling force of the pedal 8 is reliably transmitted to the rear wheel 4.

In the present embodiment, however, as shown in FIG. 5, the motor 11 is operated (energized to the motor) from the starting point A of the bicycle to the point C when the pedal 8 is depressed and a predetermined time elapses. Stop the projections 51 and 5 described above.
When the rear wheel 4 is rotated only by the pedaling force of the pedal 8 by the combination of the two, the motor 11 is energized after the time point C is exceeded, the rotation of the motor 11 is temporarily increased, and then the same speed as described above is started from the time point D. Transfer to control.

In this case, as shown in FIG. 6 (A), the projection 51 (pedal-side projection) 51 of the pedal-side drive shaft 13 before starting the vehicle.
Assuming that the motor-side drive shaft 15 and the protrusion (motor-side protrusion) 52 are at 180-degree opposite positions (original position), the pedal-side protrusion 51 rotates in the direction of arrow a at the same time when the pedal 8 is depressed. In response to this, the motor-side protrusion 52 rotates in the direction of the arrow b, and after rotating by a predetermined angle (90 degrees or less), both protrusions 51 and 52 are united. In other words, the motor 11 rotates in the direction opposite to the crank 7 and the pedal 8 runs idle until the protrusions 51 and 52 are united. However, this idling time is short because it is in the rotation angle range of 90 degrees or less as described above. It should be noted that the time point B shown in FIG. 5 represents the time point when the protrusions 51 and 52 are united.

In this embodiment, since the operation of the motor 11 is stopped until the time point C as described above, the time point B
6B, the protrusions 51 and 52 integrally rotate in the rotation direction a of the pedal-side rotation shaft 13 as shown in FIG. 6B, and the rotation of the motor-side drive shaft 15, that is, the motor 11 rotates. Increases in accordance with the rotation speed of. And time point C
When it exceeds, the acceleration operation of the motor 11 is started as described above. By this speed-up operation, the motor-side protrusion 52 advances ahead of the pedal-side protrusion 51, as indicated by the arrow c in FIG. In this embodiment, the time point D at which the acceleration control is started.
Is a time point at which both the projections 51 and 52 return to the original position where they contradict each other by 180 degrees, and at the same time when the time point D is reached, the same speed control is performed, and thereafter, similarly to the above, the pedal side drive shaft is moved. The rotation of the motor 11 is feedback-controlled according to the rotation speed St of 13 and the control delay is absorbed by the differential of the differential gear device 16. The time when the speed increasing control of the motor 11 is started is the time when the rotation of the motor 11 appropriately increases and the reverse rotation does not occur.

FIG. 7 shows the change in the rotational speed of the wheel (rear wheel 4) with time when the control system is applied to the electric motor-equipped bicycle provided with the rotation stopping means 51 and 52. This is shown in comparison with the result of the case where the same speed control is adopted for a bicycle not having it (comparative example). From this, it is clear that the idling time T ₁ of the pedal in this embodiment is significantly smaller than the idling time T ₂ of the comparative example. Particularly in this embodiment, the motor 11
Since the motor 11 rotates at the same speed in the same direction as the pedal at the time point C when the operation is started, the power consumption required for starting the motor 11 is small, which is advantageous in terms of cost.

[0028]

As described above in detail, according to the electric motor-operated bicycle of the present invention, the rotation stopping means suppresses the reverse rotation of the motor within a small range. Also, the output of the pedal drive system is effectively transmitted to the rear wheels, and idling of the pedal is minimized. Further, since the rotation stopping means only makes a slight change in the shape of the input shaft, complication of the structure and cost increase can be suppressed to the minimum. Moreover, since the differential of the differential gear device is ensured within the predetermined rotation angle range, the increase in the load on the pedal drive system due to the control delay is suppressed, and even if the motor drive system fails, sudden braking is possible. There is nothing to do. Further, when the control means for controlling the rotation speed of the motor-side drive shaft based on the rotation speed of the pedal-side drive shaft is provided, the differential gear device is appropriately returned to the differential-enabling state to guarantee the differential. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main structure of a bicycle with an electric motor according to the present invention.

FIG. 2 is a cross-sectional view showing the assembly structure of the power transmission mechanism in the overall structure of the electric motor-assisted bicycle.

FIG. 3 is a front view showing the structure of rotation stopping means in the present electric motor-operated bicycle.

FIG. 4 is a block diagram showing a control system of the electric motor-equipped bicycle.

FIG. 5 is a graph showing an example of control contents in the present bicycle with an electric motor.

FIG. 6 is a schematic diagram illustrating the control contents of the bicycle with an electric motor of the present invention.

FIG. 7 is a graph showing a control result of the bicycle with the electric motor in comparison with a comparative example.

FIG. 8 is a side view showing the overall structure of the present bicycle with an electric motor.

[Explanation of symbols]

 1 Main Frame 4 Rear Wheel 5 Sub Frame 7 Crank 8 Pedal 10 Power Transmission Mechanism 11 Electric Motor 12 Pedal Side Power Transmission Member 13 Pedal Side Drive Shaft 14 Motor Side Power Transmission Member 15 Motor Side Drive Shaft 30 Differential Case 35 Side Gear 36 Pinion Gear 43 Pedal Side rotation sensor 44 Motor side rotation sensor 48 Controller

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[Procedure amendment]

[Submission date] December 12, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Claims (2)

[Claims] 1. An output of a pedal drive system and an output of a motor drive system are combined by a differential gear device and transmitted to a rear wheel, and the output of a motor drive system is controlled according to the output of the pedal drive system. In the bicycle with an electric motor described above, a rotation stop means is interposed between the pedal-side drive shaft for rotating the side gear of the differential gear device and the motor-side drive shaft for restricting relative rotation of the both sides beyond a predetermined range. A bicycle with an electric motor characterized in that 2. The bicycle with an electric motor according to claim 1, further comprising control means for controlling the rotation speed of the motor-side drive shaft based on the rotation speed of the pedal-side drive shaft.