JP3472375B2 - Crank pedal position control device for bicycle with assist motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a power transmission system for transmitting a pedaling force of a crank pedal to a wheel, and an assist motor driven by a traveling battery is provided in the power transmission system to drive the assist motor according to the pedaling force of the crank pedal. The present invention relates to a bicycle with an assist motor, and particularly to a crank pedal position control device for the bicycle.

[0002]

2. Description of the Related Art Such a bicycle with an assist motor is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 4-321482 and 5-24.
It is known from Japanese Patent No. 6378.

[0003]

However, regardless of the presence or absence of an assist motor, it is difficult to apply a strong pedaling force when the bicycle is started without proper rotational position of the crank pedal. The bicycle was started after rotating it in the reverse direction and setting it to the initial position that suits the passengers.

The present invention has been made in view of the above circumstances, and provides a crank pedal position control device for a bicycle with an assist motor capable of automatically setting the crank pedal to an initial position that suits an occupant's taste. The purpose is to do.

[0005]

In order to achieve the above-mentioned object, the invention described in claim 1 provides an assist motor driven by a traveling battery in a power transmission system for transmitting a pedaling force of a crank pedal to wheels. interposed, a bicycle with an assist motor for driving the assist motor in accordance with the depression force of the crank pedals, a power switch that enables the assist running by the assist motor, a rotation position sensor for detecting a rotational position of the crank pedals, At start
Storage means for storing an initial position of the crank pedals,
Contact and a closing time of the crank pedals can be driven control means assist motor to match the rotation position to the stored initial position in the storage means of the power switch
The storage means is for changing the initial position stored in the storage means.
And the crank pedal is connected to the power switch.
Drive force of the assist motor when the switch is closed.
It is characterized in that it can be automatically moved to the initial position .

The invention described in claim 2 is characterized in that, in addition to the structure of claim 1, there is provided braking means for braking the rotation of the crank pedal to stop the crank pedal at the initial position. .

The invention described in claim 3 is a clan.
The power transmission system that transmits the pedaling force of the pedal to the wheels
The assist motor driven by the battery
Assist that drives the assist motor according to the pedaling force
In a bicycle with a motor,
Power switch to enable assisted driving and
A rotary position sensor that detects the rotary position of the
Storing an initial position of the class Nkupedaru in advance the time
The storage means and the crank when the power switch is closed
The initial position in which the rotational position of the pedal is stored in the storage means
Means that can drive the assist motor to match
When the first pedaling force is applied to the crank pedal at the time of starting, the rotational position of the crank pedal at that time is stored in the storage means as the initial position.

[0008]

According to each of the configurations of claims 1 to 3 , when the power switch is closed at the time of starting, the assist motor is driven and the rotational position of the crank pedal is set to a pre-stored initial position. Since it is not necessary to manually set the rotational position of 1 to the initial position, it becomes possible to easily start the vehicle.

According to the structure of claim 1, in particular,
The storage means can change the initial position stored in it.
It

[0010] In particular, according to the second aspect, a braking means for braking the rotation of the crank pedals operated when the crank pedals is rotated to the initial position by the assist motor. This prevents the crank pedal from inertially passing through the initial position.

[0011] In particular, according to the third aspect, the rotational position where the first depression force is applied to the crank pedals during startup is stored as the initial position, the crank pedals to the stored initial position at the time of the next starting Set.

[0012]

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

1 to 9 show an embodiment of the present invention. FIG. 1 is an overall side view of a bicycle, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. -3 line sectional view, FIG. 4 is FIG.
4 is a sectional view taken along line 4-4, and FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG.
6 is an enlarged view of part 6 of FIG. 4, FIG. 7 is a skeleton diagram viewed from the 7 direction of FIG. 1, FIG. 8 is a block diagram of a control system, and FIG. 9 is a flowchart for explaining the operation.

As shown in FIG. 1, the bicycle B has a V-shape in a side view.
A main frame 1 having a character shape is provided, and a handle 4 and a front wheel Wf are supported at the upper end and the lower end of a front fork 3 pivotally supported by a head pipe 2 provided at the front end of the main frame 1, respectively. To be done. The rear wheel Wr is supported by rear forks 6, 6 extending rearward from the vicinity of the lower end of the main frame 1 and reinforced by stays 5, 5. Crankshaft 7 rotatably supported at the lower end of the main frame 1 is provided with a pair of right and left crank arms 8 _L, 8 _R, the crank arm 8 _L, 8 _R respectively to the tip crank pedals 9 _L, 9 _R Is provided. Drive sprocket 10 rotated by the crankshaft 7 and the rear wheel W
The driven sprocket 11 provided on the r axle is the chain 1
When the crankshaft 7 is rotated by the pedaling force of the crank pedals 9 _L and 9 _R , the rotation of the crankshaft 7 causes the drive sprocket 10, the chain 12, and the driven sprocket 11 to rotate.
Is transmitted to the rear wheel Wr via.

The assist motor 13 provided at the bottom of the main frame 1 and connected to the drive sprocket 10 is
The pedaling force of the crank pedals 9 _L, 9 _R generates a driving force for assisting. A battery box 14 provided in the front portion of the main frame 1 accommodates a traveling battery 15 composed of a plurality of Ni-Cd batteries that drive the assist motor 13, and a power switch 16 is provided at the front end of the battery box 14.
Is provided. At the rear of the main frame 1, a control device 17 such as an electronic control unit for controlling the drive of the assist motor 13 and a motor driver is provided.

Next, the structure of the drive mechanism D of the bicycle B will be described in detail with reference to FIGS.

The gear housing for housing the drive mechanism D is
A left housing 21 that constitutes the main body thereof, and a right housing 22 that closes an opening on the right side surface of the left housing 21,
Lower housing 2 coupled to the lower surface of left housing 21
3 and 3. The upper front part of the left housing 21 is connected to the lower end of the main frame 1 by two bolts 24, 24, and the left housing 21 and the right housing 22 are connected together.
The rear forks 6 and 6 are attached to the rear by one bolt 25.
It is fastened together at the front end of. The lower housing 23 is connected to the lower surface of the left housing 21 by a plurality of bolts 26 ... (Only one is shown in FIG. 3).

The right end of the crankshaft 7 is connected to the right housing 22.
A sleeve 28 supported by a ball bearing 27 on the
Is supported on the inner periphery of the crankshaft 7 via a roller bearing 29, and the left end of the crankshaft 7 is supported on the left housing 21 via a ball bearing 30. A through hole 7 ₁ penetrating in the diametrical direction and extending in the axial direction is formed in the axially intermediate portion of the crankshaft 7. The torsion bar 31 accommodated coaxially with the crankshaft 7 inside the through hole 7 ₁ has a head 31 ₁ formed at the left end (input end) thereof coupled to the crankshaft 7 via a collar 32, and The right end (output end)
Head 31 ₂ formed is joined by press fitting into the groove formed in the inner periphery of the annular driving member 33 (see FIG. 4). As best shown in FIG. 5, the through hole 7 of the crankshaft 7
Walls facing each other in ₁ are curved in a substantially arc shape,
As a result, the head 31 ₂ on the free end side of the torsion bar 31
Of the torsion bar 31 is allowed to rotate relative to the head 31 ₁ on the fixed end side by a predetermined angle, and the maximum torsion amount of the torsion bar 31 when an excessive load is applied is restricted to prevent the torsion bar 31 from breaking. .

A first one-way clutch 35 is provided between the driving member 33 and the bevel gear 34 fixed to the inner circumference of the sleeve 28. As is clear from FIG. 5, the first
The one-way clutch 35 is pivotally supported on the outer periphery of the drive member 33 and is energized in the direction of expansion by a spring (not shown). The four ratchet pawls 36 ... And a large number of ratchets formed on the inner periphery of the bevel gear 34. Tooth 34 ₁ ...

Therefore, when the crankshaft 7 is rotated in the forward direction by stepping on the crank pedals 9 _L and 9 _R , the torque of the crankshaft 7 is the torsion bar 31, the drive member 33, the first one-way clutch 35, the bevel gear 34 and the sleeve 28. Is transmitted to the drive sprocket 10 that is spline-coupled to the outer circumference of the sleeve 28. Also, the crank pedal 9
_{When the} crankshaft 7 is rotated in the reverse direction by stepping on _L and 9 _R , the reverse rotation of the crankshaft 7 is allowed because the first one-way clutch 35 slips.

As is apparent from FIG. 3, the left housing 2
The output shaft 13 _1, which extends forward and downward from the assist motor 13 supported by _1, has its tip end supported by the lower end of the left housing 21 via a ball bearing 41. A first intermediate shaft 44 is supported by the left housing 21 and the lower housing 23 via a pair of ball bearings 42, 43, and a second intermediate shaft 47 is supported by a pair of ball bearings 45, 46. The spur gear 48 fixed to the output shaft 13 ₁ of the assist motor 13 is attached to the first intermediate shaft 44.
Of the spur gear 5 fixed to the first intermediate shaft 44 by meshing with the spur gear 50 supported by the second one-way clutch 49.
1 meshes with a spur gear 52 fixed to the second intermediate shaft 47. The bevel gear 53 fixed to the second intermediate shaft 47 meshes with the bevel gear 34 fixed to the sleeve 28.

Therefore, when the assist motor 13 rotates, the torque of its output shaft 13 ₁ is reduced to four spur gears 4.
It is transmitted to the drive sprocket 10 via 8, 50, 51, 52, the two bevel gears 53, 34 and the sleeve 28. When the driving of the assist motor 13 is stopped due to the discharge of the traveling battery 15 or the like, the crank pedal 9
The second one-way clutch 49 idles so as not to hinder the rotation of the drive sprocket 10 by the pedaling force of _L and 9 _R.

The second one-way clutch 49 is provided with a solenoid-driven lock mechanism. When the solenoid is energized, the idling side is locked and the driving force can be transmitted in both rotation directions.

A pedaling force detecting means S for detecting the pedaling forces of the crank pedals 9 _L and 9 _R includes a slider inner 61 which is slidably fitted on the outer circumference of the crank shaft 7 and rotates integrally with the crank shaft 7. Prepare A slider outer 63 is rotatably supported by a flange protruding on the outer periphery of the slider inner 61 via a plurality of balls 62. As will be apparent with reference to FIG. 6 as well, a pair of concave cam surfaces 33 ₁ and 33 ₁ are formed on the end surface of the drive member 33 on the slider inner 61 side so as to be located on the diameter thereof, and The concave cam surface 3 is provided on the end surface of the inner 61.
A pair of convex cam surfaces 61 ₁ , 6 engaging with 3 ₁ , 33 _1.
1 ₁ is formed. The cam member 33 and the slider inner 61 constitute the converting means C of the present invention.

The left housing 1 is provided with a pivot bolt 64 and a stroke sensor 65 with the crankshaft 7 interposed therebetween, and the other end of a sensor arm 66 pivotally supported by the pivot bolt 64 is detected by the stroke sensor 65. Abut the rod 65 ₁ . A crankshaft 7, a slider inner 61 and a slider outer 6 are provided at the center of the sensor arm 66.
3 is formed with an opening 66 ₁ (see FIG. 2), and a pair of protrusions 66 ₂ and 66 ₂ (see FIG. 4) are formed so as to project inward in the radial direction from the opening 66 ₁ . A spring 67 is contracted between the pair of protrusions 66 ₂ and 66 ₂ and the left housing 21.
The sensor arm 66 is urged rightward in FIG. 4 by the elastic force.
The pair of projections 66 ₂ and 66 ₂ press the slider outer 63 to press the slider inner 61 against the drive member 33 via the balls 62. As a result, the cam surfaces 33 ₁ , 33 _{1 of} the drive member 33 resiliently contact the cam surfaces 61 ₁ , 61 ₁ of the slider inner 61.

A tooth portion 3 formed on the outer periphery of a collar 32 connecting the crankshaft 7 and the head portion 31 ₁ of the torsion bar 31.
2 ₁ has a rotation speed sensor 68 supported by the left housing 21.
And the rotational position sensor 69 face each other. Speed sensor 68
Detects the rotational speed of the crankshaft 7, and the rotational position sensor 69 detects the rotational position of the crankshaft 7 (that is, the rotational positions of the crank pedals 9 _L and 9 _R ). The rotation speed sensor 68 and the rotation position sensor 69 can be integrated by superimposing the position pulse on the rotation pulse.

A tooth portion 32 formed on the outer periphery of the collar 32
_The braking means 70 is opposed to ₁ , and a braking force is applied to the rotation of the crankshaft 7 by driving the braking means 70 with a solenoid to apply a frictional force to the tooth portion 32 ₁ .
Further, the braking means 70 is not limited to such mechanical means, and electrical means such as applying a reverse voltage to the assist motor 13 or short-circuiting the current of the assist motor 13 can be adopted.

As shown in FIG. 8, the controller 17 having the control means 71 and the storage means 72 has a rotation speed sensor 68,
The rotation position sensor 69, the stroke sensor 65 and the power switch 16 are connected, and the control means 71 controls the crankshaft rotation speed, crankshaft rotation position, pedaling force, ON / OFF of the power switch 16 and storage means. An assist motor 13 and a second one-way clutch 4 having a lock mechanism based on a stored map or program.
9 and the operation of the braking means 70 are controlled.

Next, the operation of the embodiment of the present invention having the above construction will be described.

When the occupant steps on the crank pedals 9 _L and 9 _R to drive the bicycle B, the crank arms 8 _L and 8 _R
The crankshaft 7 is rotated through the torque of the crankshaft 7 through the torsion bar 31, the drive member 33, the first one-way clutch 35, the bevel gear 34, the sleeve 28, the drive sprocket 10, the chain 12 and the driven sprocket 11. Is transmitted to the rear wheel Wr. At this time, the magnitude of the pedal effort of the crank pedals 9 _L and 9 _R is detected by the pedal effort detecting means S.

That is, when the torque corresponding to the pedaling force of the crank pedals 9 _L and 9 _R acts on the torsion bar 31, the torsion bar 31 relatively rotates with respect to the crankshaft 7 by a predetermined angle. When the torsion bar 31 rotates relative to the crankshaft 7, a slider inner 61 supported by the crankshaft 7 so as not to be relatively rotatable and slidable in the axial direction is coupled to the output end of the torsion bar 31, as shown in FIG. It rotates relative to the driven member 33 in the direction of arrow a. As a result, the cam surfaces 61 ₁ , of the slider inner 61,
61 _{by 1} is pressed against the cam surface 33 _1, 33 ₁ of the driving member 33, the slider inner 61 is spring 67
The sensor arm 66, which slides on the crankshaft 7 in the direction of the arrow b against the elastic force of, and has the projections 66 ₂ and 66 ₂ pressed by the slider outer 63 integrated with the slider inner 61, moves around the pivot bolt 64. Swing to stroke sensor 65
The detection rod 65 ₁ is pressed. At this time, the stroke of the detection rod 65 ₁ of the stroke sensor 65 is the twist amount of the torsion bar 31, that is, the crank pedals 9 _L and 9 _R.
Since it is proportional to the pedaling force of, the pedaling force can be detected based on the output of the stroke sensor 65.

Thus, the control means 71 of the control device 17 is
Based on the pedal effort detected by the pedal effort detecting means S and the vehicle speed detected by the crankshaft rotation speed sensor 68, a map search is performed for the assist torque (assist amount and assist timing), and the assist motor 13 is used to exert the assist torque.
Control the drive of.

By the way, the assist torque increases / decreases in response to a change in pedaling force while the crank pedals 9 _L and 9 _R make one revolution. However, each occupant has individual differences in how to apply the pedaling force, and the pedaling force is detected. Since there is a time delay until the assist motor 13 exerts the assisting force after that, the passenger may feel uncomfortable. Therefore, the rotational positions of the crank pedals 9 _L and 9 _R (rotational positions of the crankshaft 7) detected by the rotational position sensor 69 and the pedaling force corresponding thereto are stored as learning values in the storage means 72 and accumulated. The assist amount and assist timing of the assist torque searched for on the map are corrected according to the learned value. As a result, it becomes possible for the assist motor 13 to exert an optimum assist torque according to the occupant's preference.

Next, the control of the initial positions of the crank pedals 9 _L and 9 _R at the time of starting will be described with reference to the flowchart of FIG.

Crank pedals 9 _L and 9 _R when starting
The control of the initial position is to preset the rotational positions of the crank pedals 9 _L and 9 _R to the initial position where the pedaling force is easily applied when the occupant starts the bicycle B.

The control of the initial position is executed when the occupant turns on the power switch 16 to start the assisted traveling (step S1). When it is determined that the bicycle B is traveling based on the output of the rotation speed sensor 68 when the power switch 16 is turned on, that is, when the bicycle is switched to the assist traveling while traveling only by human power, the initial position is set. Control is not executed because it is unnecessary (step S
2).

When the power switch 16 is turned on while the bicycle B is stopped in steps S1 and S2, the rotational positions of the crank pedals 9 _L and 9 _R detected by the rotational position sensor 69 are stored in the storage unit 72 as the initial positions. If it does not match (step S3), the second one-way clutch 49 is locked and the assist motor 13 is driven in reverse (step S4).

As a result, the output shaft 1 of the assist motor 13
3 ₁ torque spur gear 48, the spur gear 50, the second
One-way clutch 49, spur gear 51, spur gear 5
2, the bevel gear 53, the bevel gear 34, the first one-way clutch 35, and the torsion bar 31 through the crankshaft 7
The crank pedals 9 _L and 9 _R are rotated in the reverse direction (reverse direction). At this time, since the first one-way clutch 35 is automatically engaged and the second one-way clutch 49 is locked by the command from the control means 7, the torque of the assist motor 13 is transmitted to the crankshaft 7. can do.

When the crank pedals 9 _L and 9 _R are reversely rotated to reach the front position by a predetermined angle of the initial position, the braking means 70 is operated earlier in consideration of the time delay required for braking (step S5). When the rotational position sensor 69 detects that the crank pedals 9 _L and 9 _R have reached the initial positions stored in the storage means 72 (step S6), the assist motor 13 is stopped and the operation of the braking means 70 is stopped. Then, the crank pedals 9 _L and 9 _R are properly stopped at the initial position (step S7). The second one-way clutch 49 is automatically unlocked after stopping the crank pedals 9 _L and 9 _R.

As described above, the crank pedal 9 _L ,
The rotation position of 9 _R is automatically set to the initial position where the occupant can easily apply the pedaling force at the time of starting, so that the occupant does not need to adjust the rotation position of the crank pedals 9 _L and 9 _R each time the vehicle starts to move, It is possible to take off easily and improve convenience.

When the occupant starts pedaling with the pedaling force (this pedaling force is referred to as the first pedaling force) applied to the crank pedals 9 _L and 9 _R while the bicycle B is stopped, the crank to which the first pedaling force is applied is started. The rotational position of the pedals 9 _L and 9 _R (this rotational position is referred to as the first pedaling force introduction position) is detected (step S
8) Then, the detected first pedaling force introduction position is stored in the storage means 72 as an initial position (step S9). This memory is updated each time the vehicle is started, but the stored initial position is not changed as long as the vehicle starts from the initial position set by the assist motor 13.

However, if the occupants' preferences change,
When another occupant uses the bicycle B, if the start positions are manually changed after manually changing the initial positions of the crank pedals 9 _L and 9 _R set by the assist motor 13, the changed initial positions are updated. It is stored instead of the previous initial position that has already been stored as the initial position. In this way, the initial positions of the crank pedals 9 _L and 9 _R can be arbitrarily changed.

Although the embodiments of the present invention have been described in detail above, the present invention can be modified in various ways without departing from the scope of the invention.

[0044]

As described above, according to each of the first to third aspects of the present invention, the assist motor is operated according to the pedaling force of the crank pedal.
A bicycle with an assist motor that drives
Power switch that enables assisted driving with a motor
And the rotational position sensor that detects the rotational position of the crank pedal.
And the initial position of the crank pedal when starting
Memory means and a crank when the power switch is closed.
The initial position in which the rotational position of the pedal is stored in the storage means
Means that can drive the assist motor to match
Therefore, when the power switch for enabling the assisted traveling is closed, the crank pedal is driven by the assist motor and the initial position stored in advance in the storage means is immediately stored.
It is possible to automatically set the initial position where the occupant can easily apply the pedaling force when the vehicle starts moving , which eliminates the need to manually set the rotational position of the crank pedal to the initial position, which is convenient. Is improved.

According to the inventions of claims 1 and 2,
The storage means can change the initial position stored in it.
Noh.

[0046] According particularly to the second aspect of the present invention, since the braking means when the assist motor sets the crank pedals to the initial position to brake the crank pedals in the initial position, stops the crank pedals precisely the initial position be able to.

[0047] According particularly to the third aspect, when the first depression force is applied to the crank pedals during startup, since stored in the storage means the rotational position of the crank pedals as the initial position, by performing a time starting The initial position is automatically stored, and if the vehicle starts from a different initial position, the already stored initial position can be updated to a new initial position.

[Brief description of drawings]

[Figure 1] Overall side view of the bicycle

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG.

3 is a sectional view taken along line 3-3 of FIG.

FIG. 4 is a sectional view taken along line 4-4 of FIG.

5 is an enlarged sectional view taken along line 5-5 of FIG.

6 is an enlarged view of part 6 in FIG.

FIG. 7 is a skeleton diagram viewed from the seven directions in FIG.

FIG. 8 is a block diagram of a control system

FIG. 9 is a flowchart illustrating the operation.

[Explanation of symbols]

9 _L , 9 _R crank pedal 13 assist motor 15 running battery 16 power switch 69 rotational position sensor 70 braking means 71 control means 72 storage means D drive mechanism (power transmission system) Wr rear wheel (wheel)

─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Satoshi Honda Satoshi Wako-shi, Saitama Prefecture 1-4-1 Chuo R & D Co., Ltd. (56) Reference JP-A-6-40375 (JP, A) JP A 56-120470 (JP, A) JP 4-334688 (JP, A) JP 4-321479 (JP, A) JP 54-146358 (JP, A) JP 53-27936 (JP, A) Actual Kaihei 5-89186 (JP, U) Actual Kaihei 3-69594 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62M 23/02 B62M 3/08

Claims (3)

(57) [Claims] 1. An assist motor (13) driven by a traveling battery (15) is provided in a power transmission system (D) for transmitting pedaling force of crank pedals (9 _L , 9 _R ) to wheels (Wr). in bicycles assist motor for driving the assist motor (13) in response to the depression force applied to the crank pedals (9 _L, 9 _R), a power switch (16) to allow the assist running by the assist motor (13), wherein a rotational position sensor for detecting a rotational position of the crank pedals (9 _L, 9 _R) (69), storage means for storing an initial position of the crank pedals (9 _L, 9 _R) at the time of start (72), wherein the crank pedals during closing of the power switch _{(16) (9 L, 9} R) wherein the rotational position of the order match the stored initial position the the storage means (72) assist motor (1 Contact) and a drivable control means (71) to
The storage means (72) stores the initial position stored in the storage means (72).
The crank pedals (9 _L , 9 _R ) can be changed and the power switch
The assist motor when the switch (16) is closed.
Can be automatically moved to the initial position by the driving force of (13)
And characterized in that the crank pedal position controller in a bicycle with an assist motor. 2. A braking means (70) for braking the rotation of the crank pedal (9 _L , 9 _R ) so as to stop the crank pedal (9 _L , 9 _R ) at an initial position. A crank pedal position control device for a bicycle with an assist motor according to claim 1. 3. The pedal effort of the crank pedal (9 _L , 9 _R )
The power transmission system (D) for transmitting to the wheels (Wr) is equipped with a traveling bag.
Via an assist motor (13) driven by a terri (15)
The crank pedal (9 _L , 9 _R ) according to the pedal effort.
Self with assist motor that drives cyst motor (13)
Assisted driving by the assist motor (13) is possible during rolling
The power switch (16) and the rotational position of the crank pedals (9 _L , 9 _R ) are detected.
Rotational position sensor (69) and the crank pedal (9 _L , 9 _R )
A storage means (72) for storing a fixed position and the crank pedal when the power switch (16) is closed.
To the storage means (72) for the rotational position of the _ring (9 _L , 9 _R ).
The assist mode is set to match the stored initial position.
And a control means (71) capable of driving the computer (13)
Ri, crank pedals during start (9 _L, 9 _R) when the first depression force is applied to the crank pedals (9 _L at that time,
A crank pedal position control device for a bicycle with an assist motor , characterized in that the rotational position of 9 _R ) is stored in the storage means (72) as an initial position.