JPH08268374A - Power assist for bicycle - Google Patents

Abstract

PURPOSE: To allow easy installation on an ordinary bicycle, and provide pertinent power assistance at the time of traveling along an uphill. CONSTITUTION: The first torque transmission disc 35 fastened to a shaft joint 44 having a pedal crank connected, and rotatable under torque from the pedal crank is provided, together with the second torque transmission disc 28 fastened to a pedal crankshaft, and a gear disc member 34 coming in contact with each of the discs 35 and 28 under pressure, when the disc 35 rotates. Furthermore, the rotation speed of the disc 35 is detected with a rotation speed sensor 47 and physical displacement variables resulting from the acceleration of a bicycle and the backward tilt of the body thereof are detected with a displacement sensor. Then, when the rotation speed becomes equal to or above the preset value, and the displacement variables are equal to or above the preset magnitude, an electric motor is started and the member 34 is rotated via a reduction gear 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power assist device for a bicycle that is attached to a bicycle to assist power.

[0002]

2. Description of the Related Art Conventionally, bicycle power assist devices can be roughly classified into two types. One is that a drive switch or a control accelerator is provided in the handle portion, and the motor power can be controlled to an arbitrary size by the accelerator, which is called a motorized bicycle and requires a license. The other is to detect the pedal driving torque of human power and assist the power equivalent to human energy, which can be used without a license.

[0003]

However, the conventional power assist device for a bicycle, which can be used without a license, is a pre-assembled device for a bicycle having a special dedicated structure and is attached to an ordinary commercially available bicycle. I couldn't do that. That is, conventionally, there has been no power assist device that can be easily attached to an ordinary bicycle.

Therefore, the invention according to claim 1 can be easily attached to a commercially available ordinary bicycle to improve versatility, and can appropriately assist power not only when traveling on a flat ground but also when climbing a slope. A power assist device for a bicycle is provided.

Further, the invention according to claims 2 to 4 can be easily attached to a commercially available ordinary bicycle to improve versatility, and moreover, the pedal is depressed not only when traveling on a level ground but also when climbing a slope. By operation, proper power assistance can be done,
Further, there is provided a bicycle power assisting device capable of stopping power assist by an electric motor when going down a slope or operating a brake to suppress power consumption as much as possible.

[0006]

The invention according to claim 1 is
In a bicycle power assist device for assisting power by transmitting the rotation of an electric motor to a crankshaft or wheels via a speed reducer,
A rotation speed detecting means for detecting the rotation speed of the pedal crank and a displacement amount detecting means for detecting a physical displacement amount associated with the acceleration of the bicycle and the rearward leaning of the vehicle body are provided, and the rotation speed detecting means has a predetermined constant value. The electric motor is started when a rotational speed equal to or higher than a value is detected and the displacement amount detecting means detects a physical displacement amount equal to or larger than a predetermined fixed amount.

According to a second aspect of the present invention, an electric motor driven by a battery as a power source and a speed reducer for transmitting the rotation of the electric motor through a reduction gear are provided, and the output of the speed reducer is transmitted to a pedal crankshaft to drive power. In a power assist device for a bicycle for assisting a bicycle, a pedal crank fixed to a pedal coupling shaft coupled to the pedal crank, the first crank rotating by receiving a rotational force of the pedal crank.
And a second torque transmission plate which is fixed to the pedal crank shaft and rotates integrally with the pedal crank shaft, and when the first torque transmission plate is rotated by receiving the rotational force of the pedal crank. The first torque transmission plate is engaged with the second torque transmission plate and moved in the axial direction of the pedal crankshaft, and the respective torque transmission plates are pressed against the plate surface of the final stage gear that transmits the output of the reduction gear to the outside. A slanting and tilting engaging portion,
A friction sliding member that transmits the drive torque of the reduction gear to each torque transmission plate when each torque transmission plate is pressed against the plate surface of the final gear, a rotation speed detection unit that detects the rotation speed of the pedal crank, and a bicycle. And a displacement amount detecting means for detecting a physical displacement amount associated with the rearward leaning of the vehicle body, the rotation speed detecting means detects a rotation speed of a predetermined value or more, and the displacement amount detecting means is The electric motor is started when a physical displacement amount equal to or larger than a predetermined constant amount is detected, and the electric motor is stopped when the physical displacement amount detected by the displacement amount detecting means is less than the predetermined amount.

According to a third aspect of the invention, in the bicycle power assisting device according to the first or second aspect, the displacement amount detecting means is physically proportional to the magnitude of the acceleration and the magnitude of the rearward tilt angle of the vehicle body. The amount of displacement is variable.

According to a fourth aspect of the invention, in the power assist device for a bicycle according to the first, second or third aspect, the displacement amount detecting means rotatably supports one end of a plate member or a rod member. The other end of the plate-shaped member or the rod-shaped member changes the physical displacement amount according to the acceleration and the rearward tilt angle of the vehicle body, and the sensor detects that the displacement amount becomes a certain amount or more.

[0010]

In the present invention corresponding to claim 1, the pedal crank is rotated by the depression of the pedal. Then, when the rotation speed of the pedal crank exceeds a certain value and the physical displacement amount due to the acceleration of the bicycle and the rearward leaning of the vehicle body exceeds a certain amount, the electric motor is started and the rotation of the electric motor is decelerated. The power is transmitted to the crankshaft or wheels via the machine. Therefore, when the bicycle climbs up a hill, the amount of physical displacement changes due to the inclination of the slope, so that the amount of physical displacement becomes a certain amount or more even with relatively small acceleration.

According to the second aspect of the present invention, when the pedal crank rotates due to the depression of the pedal, the first torque transmission plate rotates, and this rotation causes the first torque transmission plate to move to the second inclined engagement portion. Engage with the torque transmission plate. Then, the first torque transmission plate moves in the axial direction of the pedal crankshaft, and each torque transmission plate comes into pressure contact with the friction sliding member provided on the plate surface of the final gear of the reduction gear. On the other hand, when the rotational speed of the pedal crank becomes a certain value or more and the physical displacement amount due to the acceleration of the bicycle and the rearward leaning of the vehicle body becomes a certain amount or more, the electric motor is started. In this way, the rotation of the electric motor is transmitted from the final stage gear of the reduction gear to each torque transmission plate via the friction sliding member, and power is assisted. Also, when going down a downhill or applying a brake, the physical displacement amount due to the acceleration of the bicycle and the rearward leaning of the vehicle body becomes less than a certain amount, and the electric motor stops.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

The pedal crank shaft of a general-purpose bicycle is standardized into two types: a square cut shaft with a screw boss and a shaft with a chrysanthemum groove with a screw hole at the center for mounting the pedal crank. . A chain wheel is attached to the right side of the vehicle body, but there is a space on the left side. Furthermore, there is a space between the chain wheel and the front wheels. Therefore, in this embodiment, the power assisting device is mounted by utilizing the space of the general-purpose bicycle.

FIG. 1 is a perspective view showing the entire structure of a bicycle.
1 is a body frame. The body frame 1 includes a head pipe 2, a top tube 3 extending rearward from the head pipe 2, and a seat tube 4 extending from the top tube 3 to a bottom bracket (not shown).
A down tube 5 extending from the head pipe 2 to the bottom bracket, a pair of left and right rear stays (not shown) extending rearward from the bottom bracket, and an upper end of the seat tube 4 and a rear end of the rear stay are connected. It is composed of a pair of left and right seat stays 6.

A front fork 7 and a handle bar 8 are held on the head pipe 2 so as to be rotatable left and right, and the front fork 7 is
A front wheel 9 is rotatably attached to the handlebar 8 and a handlebar 10 is fixed to the handlebar 8. A rear wheel 11 is rotatably attached to the rear end of the rear stay. A saddle 12 is attached to the upper end of the seat tube 4 so as to be vertically movable.

A chain wheel (not shown) is attached to the right side of the bottom bracket portion, and the chain wheel is covered with a chain wheel cover 13. A right pedal crank 14a and a pedal 15a are provided outside the chain wheel cover 13.

On the left side of the bottom bracket,
The gear case 16 is attached, and the electric motor 17 is fixed to the inner surface of the gear case 16 on the front end side. A battery case 18, which is a power source, is detachably attached to the chain wheel cover 13. A left pedal crank 14b and a pedal 15b are provided outside the gear case 16. A circuit box 19 incorporating a drive circuit for driving the electric motor 17 and a displacement amount sensor as displacement amount detecting means is attached to the side surface of the battery case 18 on the gear case side.

FIG. 2 is a view of the bicycle viewed from above with the body frame 1 omitted, showing the arrangement of the gear case 16, the battery case 18, and the circuit box 19. A plurality of batteries, for example, three 12 V sealed lead acid batteries are connected in series and housed in the battery case 18, and driving power is supplied from each of the batteries to the electric motor 17.

As shown in FIG. 3, the gear case 16 accommodates a speed reducer 23 including a plurality of speed reduction gears 22, ... Including a final stage gear 21. The reduction gear 22 is rotatably attached by a ball bearing 25 to a shaft 24 fixed in the case 16. Then, the second torque transmission plate 28 is attached to the pedal crank shaft 27 rotatably attached to the bottom bracket 26, and the tightening nut 2
It is fixed to the pedal crankshaft 27 by 9.

As shown in FIGS. 5 and 7, the second torque transmission plate 28 projects one end side of the central portion thereof, and a rectangular hole 31 is formed in the center of the projecting portion 30. The pedal crank shaft 27 is passed through. Further, the other end side of the central portion is also projected, the inside of the projecting portion 32 is formed into a cylindrical shape, and one of the members of the oblique engaging portion is formed at a position opposite to the inner wall of the projecting portion 32. Inclined protrusion 3
3, 33 are provided.

A ring-shaped gear disk member 34, in which the ring-shaped final stage gear 21 is screwed to the peripheral portion, is fitted to the protruding portion 32 of the second torque transmission plate 28.
A first torque transmission plate 35 is fitted inside the protrusion 32 of the second torque transmission plate 28.

As shown in FIGS. 4 and 6, the first torque transmission plate 35 projects at one end of the central portion thereof, and a circular hole 37 is formed in the center of the projecting portion 36. The tightening nut 29 is housed.
At the opposite positions on the outer peripheral surface of the projecting portion 36, there are provided slanting projections 38, 38 which constitute the other member of the slanting engaging portion. When the first torque transmission plate 35 is fitted to the second torque transmission plate 28, the inclined surfaces of the inclined protrusions 38, 38 are the inclined surfaces of the inclined protrusions 33, 33 of the second torque transmission plate 28. The protrusion 36 of the first torque transmission plate 35 is inserted into the inside of the protrusion 32 of the second torque transmission plate 28 with the gear disc member 34 being sandwiched between the protrusion 36 and the inclined protrusion. After rotating leftward so that 33, 33 and 38, 38 face each other, a stopper screw is pushed in from the bottom surface of the second torque transmission plate 28 to prevent reverse rotation of the first torque transmission plate 35 and be integrated. ing.

As shown in FIG. 8A, the ring-shaped gear disk member 34 to which the final stage gear 21 is fixed has a spring on the innermost peripheral portion of the surface facing the second torque transmission plate 28. One end of the spring 39, which is a member, is fixed, and the small-diameter ring member 40 is fixed to the other end of the spring 39. A plurality of circular first friction sliding members 41, 41, ... Are attached to the end surface of the small diameter ring member 40 at regular intervals. In addition, the gear disc member 34
As shown in FIG. 8B, the second frictional sliding member 42 is formed on the outermost peripheral portion of the surface facing the first torque transmission plate 36.
Is fixed.

A central portion on the other end side of the first torque transmission plate 36 is projected, and a shaft coupling 44, which is a pedal connecting shaft, is screwed to the projected portion 43, and the left pedal 15b is attached to the shaft coupling 44. The pedal crank 14b is fixed by a tightening nut 45. Then, a cap 46 for protecting the tightening nut 45 from being exposed to the outside is screwed onto the pedal crank 14b.

The pedal 15 is located inside the gear case 16 at a position facing the other end of the first torque transmission plate 35.
a, 15b, that is, a rotation speed sensor 47 as a rotation speed detecting means for detecting the rotation speed of the pedal crank 14b is arranged, and the first torque transmission plate 35 is provided.
A magnet 48 magnetized in multiple poles is adhered and fixed to the outer peripheral portion of the protruding portion 43. The rotation speed sensor 47 includes, for example, a Hall element, and detects a change in the magnetic pole of the magnet 48 by the rotation of the first torque transmission plate 35 accompanying the rotation of the pedal crank 14b. The rotation speed of 14b is detected. It should be noted that when the pedals 15a and 15b are at the upper and lower positions, the magnet 48 is arranged so that the magnet 48 does not exist at the position facing the sensor 47.
Is partially cut.

The speed reducer 23 has, for example, four speed reduction gears, and the fourth speed is the final speed gear 21. And
For example, the rotation speed of the electric motor 17 is 7,000 rpm,
This is reduced to 1,500 rpm by the first reduction gear 22, reduced to 460 rpm by the next second reduction gear 22, and further reduced to 200 rpm by the third reduction gear 22. The final gear 21 of the eye reduces the speed to 54.8 rpm.

A displacement amount sensor sensor 49 shown in FIG. 9 is incorporated in the circuit box 19. This displacement amount sensor 49 is a miniature having a rotatable outer ring on one side deviated to one of the upper parts of the case 50, as shown in a side view in (a) and a sectional view taken along line AA in (b). Bearing 51
The one end of a plate member 52 is integrally fixed to the outer ring of the miniature bearing 51, and the other end of the plate member 52 extends to the vicinity of the bottom of the case 50 to be slightly wider. On the edge. And the case 50
A photo sensor 53 is arranged at the end of the bottom of the sheet, which is offset to the other side. In the photosensor 53, a light emitting diode and a phototransistor are arranged to face each other with a predetermined space.

In this displacement amount sensor 49, the back surface 50a of the case 50 is vertically fixed to the inner wall of the circuit box 19 so that one side to which the plate member 52 is attached faces the front of the bicycle. The displacement sensor 49 is a plate-shaped member 52 when the bicycle is stopped on a flat ground.
Of the photo sensor 5
The light from the light emitting diode to the phototransistor 3 is not blocked by the plate member 52.

When the bicycle runs to generate acceleration or climbs a slope, the plate member 52 rotates backward, and when the physical displacement amount exceeds a certain amount, the other end of the plate member 52 emits light. It blocks light from the diode to the phototransistor. That is, the photo sensor 53 detects that the plate member 52 is displaced by a certain amount or more. Also, when the brake is applied during traveling or when the vehicle is going down a slope, the plate-shaped member 52 is rotated forward to release the light blocking from the light emitting diode to the phototransistor.

FIG. 10 is a block diagram of a control circuit incorporated in the circuit box 19, which is provided with a CPU 54 and an I / O port 55 which constitute the control unit main body. Then, the CPU 54 takes in the rotation speed detection signal of the pedal crank 14b from the rotation speed sensor circuit 56 including the rotation speed sensor 47 via the I / O port 55 and the displacement amount sensor circuit including the displacement amount sensor 49. 57
When the rotation speed is equal to or higher than a preset constant value and the displacement is equal to or higher than a preset constant value, a motor drive signal is sent to the motor control circuit 58 via the I / O port 55. It is supposed to be supplied. The motor control circuit 58 takes in a motor drive signal and drives and controls the electric motor 17.

Specifically, as shown in FIG. 11, the motor control circuit 58 has an NPN transistor Tr1 connected between the + e1 terminal and the ground via a resistor R1, and the collector of this transistor Tr1 via a resistor R2. Is connected to the inverting input terminal (-) of the differential amplifier AM. The non-inverting input terminal (+) of the differential amplifier AM has a resistor R3 and a resistor R3.
4 is grounded in series and resistors R5 and R6
Are grounded in series. The connection point of the resistors R3 and R4 is connected to the + e2 terminal via the resistor R7.

The output terminal of the differential amplifier AM is a resistor R8.
Is connected to the base of the NPN transistor Tr2 via the resistor R8 and the resistor R8 and the resistor R9, and is also connected to its own non-inverting input terminal (+). The transistor Tr2
Has a collector connected to the + E terminal via the electric motor 17, an emitter grounded via a resistor R10, and a resistor R
It is connected via 11 to the inverting input terminal (-) of the comparator CM.

The comparator CM has a non-inverting input terminal.
The (+) is grounded via a resistor R12 and a resistor R13 in series. The connection point of the resistors R12 and R13 is added via the resistor R14
It is connected to the e2 terminal. The comparator CM has an output terminal connected to its own inverting input terminal (-) via a resistor R15 and a resistor R16 in series, and a connection point of the resistors R5 and R6 via a resistor R15 and a resistor R17 connected in series. Connected.

As the electric motor 17, for example, a universal motor having a torque drooping characteristic, which can smoothly assist the torque even when the bicycle is started, and decreases the torque that can assist the power as the driving speed increases, is used. ing.

The motor control circuit 58 detects and limits the starting current in order to prevent the risk of sudden start and protect the battery. That is, the transistor Tr2
A resistor R10 and a comparator CM connected in series with the above control the current so that an overcurrent does not flow at the time of starting. Specifically, when the terminal voltage of the resistor R10 rises too much due to an increase in current, the output of the comparator CM goes low, which causes the output of the differential amplifier AM to go low, turning off the transistor Tr2 and turning on the resistor. When the terminal voltage of R10 drops, the output of the comparator CM goes to high level, which causes the output of the differential amplifier AM to go to high level, turning on the transistor Tr2. This prevents an excessive acceleration from being applied at the time of startup and an overcurrent from flowing to the battery 23.

When the transistor Tr1 is turned on by the motor drive signal, the motor control circuit 58 raises the output level of the differential amplifier AM to turn on the transistor Tr2, thereby rotating the electric motor 17. When the motor drive signal is stopped and the transistor Tr1 is turned off, the output level of the differential amplifier AM becomes low level and the transistor Tr2 is turned off, thereby stopping the rotation operation of the electric motor 17.

In the power assisting device having such a structure, the left pedal crank 14b and the shaft coupling 44 of the existing bicycle are removed, and the second torque transmission plate 2 is attached to the pedal crank shaft 27.
After fixing 8 and fixing the gear case 16 to the vehicle body, the shaft coupling 44 is fixed to the first torque transmission plate 35, and further, the left pedal crank 14b is fixed to the shaft coupling 44 with the tightening nut 45. In this way, it can be easily attached to existing bicycles.

In the state before the operation of the bicycle in which the pedal is not depressed, the second friction sliding member 42 fixed to the gear disk member 34 is pressed against the first torque transmission plate 35 only by the force of the spring 39, The first friction sliding member 41 fixed to the small-diameter ring member 40 has the second torque transmission plate 28.
Is pressed against.

When the operation of the bicycle is started by stepping on the pedals 15a and 15b in this state, the first torque transmission plate 35
Is rotated by the rotation of the pedal crank 14b, the inclined surface of the inclined projection 38 of the first torque transmission plate 35 comes into contact with the inclined surface of the inclined projection 33 of the second torque transmission plate 28, and the first torque transmission is performed. The plate 35 moves in the axial direction of the pedal crankshaft 27 while rotating. As a result, the second part of the gear disk member 34 is
The friction sliding member 42 is strongly pressed against the first torque transmission plate 35, and the first friction sliding member 41 of the small-diameter ring member 40 is also strongly pressed against the second torque transmission plate 28.

On the other hand, when the first torque transmission plate 35 rotates, the magnet 48 also rotates and the rotation speed sensor 47 detects the rotation speed of the pedal crank 14b. Further, the pedal crank shaft 27 is rotated by the rotation of the pedal crank 14b, and the bicycle moves forward to generate acceleration. This causes the other end of the plate-shaped member 52 of the displacement amount sensor 49 to rotate backward.
Then, when the physical displacement amount of the plate-shaped member 52 exceeds a certain amount, the photo sensor 53 detects the plate-shaped member 52.

In this way, the CPU 54 controls the rotation speed detection signal from the rotation speed sensor circuit 56 and the displacement amount sensor circuit 5
The displacement amount detection signal from 7 is taken in, and when the rotation speed is equal to or higher than a certain value and the displacement amount is equal to or more than a certain amount, a motor drive signal is supplied to the motor control circuit 58 via the I / O port 55. As a result, the motor control circuit 5
8 starts the electric motor 17.

When the electric motor 17 is started, the rotational torque of the electric motor 17 is transmitted to the final stage gear 21, that is, the gear disk member 34 via the speed reducer 23, and further to the second frictional member 41 via the first friction sliding member 41. It is transmitted to the torque transmission plate 28 and also transmitted to the first torque transmission plate 35 via the second friction sliding member 42. At this time, each torque transmission plate 2
The magnitude of the torque transmitted to the springs 8 and 35 depends on the spring 3
9 is determined by the product of the pressure contact force of the friction sliding members 41, 42, the friction coefficient of the friction sliding members 41, 42, and the average radius of the friction surfaces of the friction sliding members 41, 42. Since the average radius of the friction surface of the friction sliding member 42 is larger than the average radius of the friction surface of the friction sliding member 41, the first torque transmission plate 35
The torque transmitted to the second torque transmission plate 28 is larger than the torque transmitted to the second torque transmission plate 28.

In this way, even if the pedal torque due to human power is small, the power from the electric motor 17 is appropriately assisted by the power, whereby the pedal crankshaft 27 obtains sufficient rotational torque to move the bicycle. Further, since the torque transmitted to the first torque transmission plate 35 is larger than the torque transmitted to the second torque transmission plate 28, the component force in the axial direction of the pedal crankshaft 27 is added at the inclined engagement portion. Then, the amount of assistance increases in accordance with the pedaling force by human power, and power assistance is performed.

Therefore, even if the torque from the pedal 15b on the left side due to human power is reduced, the pedal 15a on the right side is also reduced.
Even in the cycle of stepping on, the torque transmitted from the electric motor 17 causes the torque transmission plates 28 and 35 and the disk member 34 to move.
The pressure contact force with can be maintained sufficiently. Therefore, although the speed reducer 23 is attached only to the left side, sufficient power assistance can be provided regardless of whether the pedal is pedaled from the left or right pedal. Moreover, when the left pedal 15b is pedaled, the torque transmission plates 28 and 35 and the gear disc member 3 are proportional to the stepping force.
The pressure contact force with 4 increases, and the auxiliary power can be increased.

When the pedal 15a or 15b reaches the lower position, the detection of the rotation speed of the pedal crank 14b by the rotation speed sensor 47 is interrupted. At this time,
The torque can be transmitted by the contact pressure only by the pressure of the spring 39. This also applies when the rotation of the pedal is stopped. The torque at this time is 10 kg · cm
The pedal can be rotated in the reverse direction with a light force that gives almost no discomfort.

Furthermore, since a motor having a drooping torque characteristic is used as the electric motor 17 and the starting torque of this motor is limited to a certain value or less, the rotational speed of the final gear is at the start or at a low speed. The rotation speed becomes higher than the rotation speed, and the power assist by the frictional force of the friction sliding member can be sufficiently performed.

When the bicycle is started uphill, the other end of the plate-shaped member 52 of the displacement sensor 49 is already displaced rearward by the slope of the slope.
Therefore, in this state, depress the pedals 15a and 15b,
When the bicycle starts to be driven, the physical displacement amount of the plate-shaped member 52 becomes a predetermined amount or more and the photo sensor 53 detects the plate-shaped member 52 even if a large acceleration does not occur. For example, the pedals 15a and 15b are 2 to 3 km / h.
The electric motor 17 is activated only by starting to rotate at a considerably low speed. In this way, since the electric motor 17 can be started and power assistance can be obtained even with a small acceleration on the uphill,
It requires less force to depress the pedal, and can provide appropriate power assistance for climbing uphill.

When the vehicle is traveling downhill or the brake is applied, the other end of the plate member 52 of the displacement sensor 49 is displaced forward and out of the detection range of the photo sensor a53. As a result, the CPU 54 stops the supply of the motor drive signal to the motor control circuit 58. This causes the motor control circuit 58 to stop the operation of the electric motor 17. Therefore, the operation of the electric motor 17 is stopped even when the pedals 15a and 15b are rotating at a high speed, so that the pressure contact between the first and second tokule transmission plates 35 and 28 and the gear disc member 34 is performed. Is very safe because only the pressure contact force by the spring 39 does not apply the torque from the electric motor 17. Further, since the operation of the electric motor 17 is immediately stopped, the power consumption of the battery can be suppressed as much as possible.

Next, another embodiment of the present invention will be described with reference to the drawings. The same parts as those in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 12, a gear case 61 having an electric motor and a speed reducer is fixed to the head pipe 2, and the output pinion of the speed reducer of the gear case 61 is brought into contact with the rim of the front wheel 9 to reduce the rotational force of the electric motor. It is configured to be directly transmitted to the front wheels 9 via the machine.

As shown in FIG. 13, the pedal crankshaft 27 is internally provided with a ring-shaped magnet 6 which is locally magnetized.
A rotary member 63 that fixes 2 is attached. Further, a ring member 64 is fixed to the bottom bracket 26, a circuit board 66 is fixed to the ring member 64 via a support member 65, and a hall element 67 constituting a rotation speed sensor is attached to the tip of the circuit board 66. . The Hall element 67 is arranged inside the magnet 62 so as to face it.

A shaft joint 44 is screwed to the outside of the rotary member 63, and the left pedal crank 14 is attached to the shaft joint 44.
b is fixed by a tightening nut 45.

When the pedal crankshaft 27 rotates,
The rotating member 63 rotates, and the magnet 62 rotates accordingly. The hall element 67 outputs an ON / OFF signal having a pulse interval proportional to the rotation speed of the magnet 62, that is, the rotation speed of the pedal crankshaft 27.
The rotation speed detection signal is output by processing the ON / OFF signal from the hall element 67 by the circuit speed sensor circuit 56. Further, when the bicycle moves forward, the displacement sensor 49 provided in the circuit box 19 detects that the physical displacement of the plate-shaped member 52 has become equal to or more than a certain amount, and the photosensor 53 detects the displacement.
The displacement amount sensor circuit 57 processes the output of the photo sensor 53 to output a displacement amount detection signal.

Therefore, the CPU 54 takes in the rotation speed detection signal and the displacement amount detection signal, and supplies a motor drive signal to the motor control circuit 58 when the rotation speed exceeds a certain value and the displacement amount exceeds a certain amount. This allows
The motor control circuit 58 starts the electric motor in the gear case 61.

When the acceleration of the electric motor is small, the main current is chopper-controlled to keep the current small. As a result, it is possible to prevent power assistance beyond the pedal depression force. Further, as the pedal depression force increases, the acceleration also increases in proportion to the force, so the main current of the electric motor is determined so that power assistance corresponding to the human power at that time is performed.

Also in this embodiment, the gear case 61, the rotating member 63, the hall element 67, etc. can be easily attached to the existing bicycle. Then, it is possible to perform power assistance corresponding to human power to depress the pedal. In addition, the motor is started with a small acceleration on the uphill, and appropriate power assistance can be provided on the uphill. Therefore, the same effect as that of the above embodiment can be obtained.

In each of the above embodiments, the plate-shaped member is used as the member of the displacement amount sensor that is displaced according to the change in acceleration and the slope of the slope, but this may be a rod-shaped member.

Further, in each of the above-mentioned embodiments, one end of the plate-like member is fixed to the rotatable outer ring of the miniature bearing as the displacement amount detecting means, and the other end of the plate-like member is used as the free end to detect acceleration changes and slopes. A displacement amount sensor having a configuration in which a rotation amount, that is, a physical displacement amount is changed according to a gradient and a photo sensor detects when the displacement amount exceeds a certain amount is used, but the present invention is not necessarily limited to this. 14
The displacement amount sensor 70 having the configuration shown in FIG.

This displacement amount sensor 70 is provided in a substantially hollow rectangular parallelepiped case 72 having an inclined bottom surface 71, as shown in a plan view in (a) and a sectional view taken along line BB in (b). A steel ball 73 is swingably enclosed so that the steel ball 73 moves in the direction indicated by the arrow in the figure, that is, in the direction of going up the inclined surface of the inclined bottom surface 71 according to the acceleration of the bicycle and the slope of the uphill. Has become. Then, for example, three photosensors 74a, 74b, 74c composed of a light emitting diode and a phototransistor are arranged at predetermined positions on the side wall of the case 72 in the moving direction of the steel ball 73 at regular intervals. Whether each photo sensor 74 is moving to the position
By detecting with a, 74b, and 74c, the physical displacement amount according to the magnitude of the acceleration and the slope of the uphill is detected.

Even if such a displacement sensor 70 is used, it is possible to detect whether or not the physical displacement amount exceeds a certain amount depending on the magnitude of the acceleration and the slope of the uphill.

[0060]

As described above, according to the invention according to claim 1, it can be easily attached to a commercially available ordinary bicycle and the versatility can be improved, and moreover, it is suitable not only when traveling on a level ground but also when climbing a slope. It can be used for power assistance.

According to the inventions corresponding to claims 2 to 4,
It can be easily attached to commercially available ordinary bicycles to improve versatility, and moreover, when driving downhill as well as on level ground, proper power assist can be provided by depressing the pedals, and when going downhill. Power consumption can be suppressed as much as possible by stopping the power assist by the electric motor during brake operation.

[Brief description of drawings]

FIG. 1 is a perspective view of a bicycle showing an embodiment of the present invention.

FIG. 2 is a view of the bicycle of the embodiment viewed from above with the body frame omitted.

FIG. 3 is a partial cross-sectional view of the left pedal crankshaft portion of the embodiment.

FIG. 4 is a perspective view of a first torque transmission plate of the embodiment.

FIG. 5 is a perspective view of a second torque transmission plate of the embodiment.

6A and 6B are left and right side views and a sectional view of the first torque transmission plate of the embodiment.

FIG. 7 is a left and right side view and a cross-sectional view of a second torque transmission plate of the embodiment.

8A and 8B are views showing a configuration of a final stage gear and a gear disc member of the embodiment, FIG. 8A is a perspective view of a surface facing a second torque transmission plate, and FIG. 8B is a first torque transmission plate. The side view of the surface facing.

FIG. 9 is a diagram showing a configuration of a displacement amount sensor of the embodiment,
(a) is a side view, (b) is a sectional view taken along the line AA of (a).

FIG. 10 is a block diagram showing a control circuit of the embodiment.

11 is a circuit diagram showing a specific circuit configuration of the motor control circuit of FIG.

FIG. 12 is a perspective view of a bicycle showing another embodiment of the present invention.

FIG. 13 is a partial cross-sectional view of the left pedal crankshaft portion of the embodiment.

FIG. 14 is a diagram showing another embodiment of the displacement amount sensor, (a)
Is a plan view, (b) is a sectional view taken along line BB of (a).

[Explanation of symbols]

 16 ... Gear case 17 ... Electric motor 21 ... Final stage gear 23 ... Reduction gear 27 ... Pedal crankshaft 28 ... Second torque transmission plate 33, 38 ... Inclined projection 34 ... Gear disc member 35 ... First torque transmission plate 41, 42 ... Friction sliding member 47 ... Rotation speed sensor 48 ... Magnet 49 ... Displacement amount sensor 54 ... CPU 58 ... Motor control circuit

Claims (4)

[Claims] 1. A bicycle power assisting device for assisting power by transmitting the rotation of an electric motor to a crankshaft or wheels via a speed reducer, a rotational speed detecting means for detecting a rotational speed of a pedal crank, and a bicycle acceleration. And a displacement amount detecting means for detecting a physical displacement amount associated with the rearward leaning of the vehicle body, wherein the rotation speed detecting means detects a rotation speed of a predetermined value or more,
A power assist device for a bicycle, wherein the electric motor is started when the displacement amount detecting means detects a physical displacement amount equal to or more than a predetermined fixed amount. 2. A power source for a bicycle, comprising: an electric motor driven by a battery as a power source; and a speed reducer for transmitting the rotation of the electric motor through a reduction gear. The output of the speed reducer is transmitted to a pedal crankshaft to assist power. In the auxiliary device, a pedal crank is fixed to a connected pedal connecting shaft, and a first torque transmission plate that rotates by receiving the rotational force of the pedal crank and the pedal crank shaft are fixed and integrated with the pedal crank shaft. When the rotating second torque transmission plate and the first torque transmission plate rotate by receiving the rotational force of the pedal crank, the first torque transmission plate is engaged with the second torque transmission plate. Along with the tilted engaging portion, the pedal crankshaft is moved in the axial direction so that the torque transmission plates are brought into pressure contact with the plate surface of the final stage gear that transmits the output of the speed reducer to the outside. A friction sliding member that transmits the drive torque of the reduction gear to each torque transmission plate when the torque transmission plates are pressed against the plate surface of the stepped gear, and a rotation speed detection unit that detects the rotation speed of the pedal crank. When,
Displacement amount detecting means for detecting a physical displacement amount associated with the acceleration of the bicycle and the rearward leaning of the vehicle body is provided, and the rotational speed detecting means detects a rotational speed of a predetermined value or more, and the displacement amount. When the detection means detects a physical displacement amount equal to or more than a preset predetermined amount, the electric motor is started, and when the physical displacement amount detected by the displacement amount detection means is less than the predetermined amount, the electric motor is stopped. A power assist device for a bicycle, which is characterized in that 3. The bicycle power according to claim 1, wherein the displacement amount detecting means varies the physical displacement amount in proportion to the magnitude of the acceleration and the magnitude of the rearward tilt angle of the vehicle body. Auxiliary device. 4. The displacement amount detecting means rotatably supports one end of a plate-shaped member or a rod-shaped member, and the other end side of the plate-shaped member or the rod-shaped member physically corresponds to the acceleration and the rearward tilt angle of the vehicle body. The power assist device for a bicycle according to claim 1, wherein the amount of displacement is varied, and a sensor detects that the amount of displacement exceeds a certain amount.