JP2001130476A - Electric power-assisted bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-weight and inexpensive electric-power assisted bicycle having an electric-power assisted drive unit capable of being retrofitted easily on a normal bicycle. SOLUTION: This electric-power assisted bicycle comprises a bicycle body 1A having a foot drive chain sprocket 7 rotated by a foot operation and an electric-power assisted drive unit 10 installed on the bicycle body 1A. The electric-power assisted drive unit 10 further comprises an electric motor 31, a foot driven chain sprocket 9 taking in a power from the foot drive chain sprocket 7 as a foot power through a first chain 8 and a main operating chain sprocket 11 rotated by a power formed of the foot power taken in and an assist power by the electric motor 31. The power of the main operating chain sprocket 11 is transmitted to the rear wheel of the bicycle body 1A through a second chain 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrically assisted bicycle, and more particularly to a drive unit mounting structure and structure.

[0002]

2. Description of the Related Art FIG. 14 and FIG.
1 shows a side view and a plan view of a bicycle auxiliary power unit described in Japanese Patent No. 49277. In this auxiliary power unit, a first freewheel 02 and a second freewheel 03 are mounted on a hub 01 of a rear wheel, and a first chain 05 is provided between the first freewheel 02 and a drive-side chain sprocket 04. The second chain 08 is suspended between the second freewheel 03 and the chain sprocket 07 attached to the output shaft of the driving motor 06.
Is suspended.

In the middle of the first chain 05, a torque detector 09 is provided. This torque detector 09 is
It has a shaft that is rotated by the action of tension applied to the chain 05, and converts the rotation angle of this shaft into a corresponding electric quantity (for example, the magnitude of electric resistance or electric capacity).

When the rider steps on the pedal 014, the stepping force acts on the first chain 05 via the crank 015 and the drive-side chain sprocket 04. Accordingly, a tension corresponding to the stepping force is generated in the first chain 05, and the tension is detected by the torque detector 09.

When starting, accelerating, or climbing a hill, the pedal 014 is strongly depressed, so that the shaft of the torque detector 09 rotates by a predetermined angle or more.
In this case, electric power is supplied to the motor 06,
6 is transmitted to the second freewheel 03 via the chain sprocket 07 and the second chain 08 attached to its output shaft, and as a result, the rear wheels are driven by human power and the motor 06 generates driving torque. It is driven by the combined torque of the torques.

In the above-described auxiliary power unit, a second freewheel 03 attached to a rear wheel hub 01 and a second chain 08 wound around the freewheel 03 are positioned so as to protrude largely in the width direction of the bicycle. There is a disadvantage that. Also, the second freewheel 03 is attached to the hub 01
The extension (output shaft) of the hub 01 is cantilevered and is easily bent, so that it is difficult to balance the left and right of the hub 01. Further, since the power unit is located closer to the rear wheels, the weight distribution of the bicycle is biased toward the rear wheels, so that
Bicycle steering tends to be unstable due to the weight of the front wheels being too light.

Therefore, various proposals have been made to reduce the size of the bicycle in the axial direction and to improve the weight distribution of the front and rear wheels. For example, Japanese Patent Application Laid-Open No. 7-40878 proposes an auxiliary power unit in which an electric power unit is arranged coaxially with a crankshaft and an electric motor is arranged on the vehicle body front side of the crankshaft. According to this auxiliary power unit, the weight distribution balance of the vehicle body as a bicycle is improved, and at the same time, the power unit contains the pedaling torque detecting means, the one-way clutch, and the like, so that the size can be reduced.

[0008] However, although this auxiliary power unit is well integrated as a power unit, the hanger lug portion, which is a mounting portion of a normal bicycle pedal crank, is removed and the power unit is mounted there. Making frames is difficult. Also, weight gain and cost are increased significantly to maintain the required strength.

[0009] Japanese Patent Application Laid-Open No. 9-1970 discloses an auxiliary power unit that can be easily mounted without greatly changing the structure of a normal bicycle. In this auxiliary power unit, an electric motor and a mechanism for reducing the rotation speed are housed in a case, and the case is rotatably supported at a front position of the bicycle with respect to a center axis of a hanger lug of the bicycle. Then, while inserting the hollow output shaft of the reduction mechanism into the hanger lug of the bicycle, the pedal crankshaft is rotatably inserted into the hollow portion of the output shaft, and the rear wheel drive chain is wound around the pedal crankshaft. Sprocket is installed. The case is fixed to the bicycle frame so as not to rotate itself. According to the auxiliary power unit having this configuration, it is not necessary to modify the configuration of the bicycle main body except when replacing parts around the axis of the pedal crank.

[0010]

Since an electric bicycle with an auxiliary power unit is mainly powered by stepping, the feeling of running as a normal bicycle using a foot pedal is emphasized. Accordingly, it is desired that the auxiliary power unit be lighter and less expensive. The conventional electric bicycle with an auxiliary power unit described in JP-A-7-40878 is
The weight of the bicycle is high and the cost is high, since the structure of the normal bicycle is greatly changed to install the auxiliary power unit.

On the other hand, the conventional example disclosed in Japanese Patent Application Laid-Open No. 9-1970 discloses a structure in which the structure of a normal bicycle is not changed as much as possible and an auxiliary power unit can be retrofitted. And cost reduction.
However, in this conventional example, since a hollow shaft or a crankshaft is inserted into the hanger lug portion, if the inner diameter of the hanger lug is to be used as it is, the diameter of these shafts must be set small. Disappears. Since a large stepping force acts on the shafts, setting the diameter to be small may cause insufficient strength of the shafts. Further, since the hollow output shaft is inserted into the hanger lug of the bicycle, there is also an inconvenience that a bearing used for a pedal crankshaft of a normal bicycle cannot be used.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a lightweight and inexpensive electric assist bicycle including an electric assist drive unit that can be easily attached to a normal bicycle. It is an issue.

[0013]

According to a first aspect of the present invention, there is provided a bicycle body having a foot drive chain sprocket rotated by a stepping operation, and an electric assist drive unit attached to the bicycle body. An assist drive unit, an electric motor, a foot driven driven chain sprocket that takes in the power of the foot drive chain sprocket as the foot power via the first chain, a power obtained by combining the taken foot power and the assist power of the electric motor. And a driving chain sprocket rotated by the driving shaft, and the power of the driving chain sprocket is transmitted to a rear wheel of the bicycle body via a second chain. According to a second aspect of the present invention, in the first aspect of the invention, the foot driven driven sprocket and the driven sprocket are arranged concentrically. According to a third aspect of the present invention, in the first or second aspect, the electric assist drive unit is located in front of a hanger lug of the bicycle main body, and an upper portion of a casing of the electric assist drive unit is attached to the bicycle main body. In addition, the casing is provided with a support member that contacts the hanger lug to support the casing. According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the upper part of the casing of the electric assist drive unit is pivotally attached to an attachment member fixed to the bicycle body, and the attachment member and the electric assist drive unit are connected to each other. A supporting means for supporting the electric assist drive unit is interposed therebetween, and the electric assist drive unit is pivotally displaced around the pivoted portion by the support means.
It has a take-up function to adjust the tension of the chain. According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the electric assist drive unit is positioned in front of a hanger lug of the bicycle main body, and an upper portion of a casing of the electric assist drive unit is pivotally attached to the bicycle main body. And supporting means for supporting the casing by abutting the hanger lug on the casing, wherein the supporting means is configured to swing-displace the electric assist drive unit about the pivoted portion and to provide the second It has a take-up function to adjust the tension of the chain. According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the support means has a structure including a connecting portion for connecting and fixing itself to the bicycle body. According to a seventh aspect of the present invention, in any one of the first to sixth aspects of the present invention, the electric assist drive unit has a hollow deceleration output shaft, and a reduction mechanism for reducing the rotation speed of the electric motor;
A sun gear provided on a rotatable sun gear shaft concentric with the reduction output shaft, an internal gear directly connected to the foot driven chain sprocket, and the sun gear and the internal gear supported by a planetary gear carrier. A planetary gear mechanism having a planetary gear that rotates planetarily between the gears, and a planetary gear mechanism interposed between the reduction output shaft and the shaft of the driven chain sprocket, and the reduction output shaft drives the driven chain sprocket. A first one-way clutch that is engaged when the planetary gear carrier and the driving chain sprocket are engaged, and a second one that is engaged when the planetary gear carrier drives the driving chain sprocket. And a one-way clutch, which is housed in the casing. According to an eighth aspect of the present invention, in the invention of the seventh aspect, a stepping torque detecting means for detecting a stepping torque and a controller for controlling power supplied to the electric motor based on the stepping torque are provided in the casing. It is built-in. The invention of claim 9 is the invention of claim 8
In the invention, the stepping torque detecting means includes a torque detecting arm that swings with the rotation of the sun gear shaft, and a spring that applies a force proportional to the swing angle of the torque detecting arm to the torque detecting arm. And an angle detecting means for detecting a swing angle of the torque detecting arm as a stepping torque. According to a tenth aspect of the present invention, in the ninth aspect of the present invention, the torque detection arm includes a fan-shaped rack along a circumference around a rotation axis of the pinion, and the angle detection means meshes with the rack. And a potentiometer interlocked with the pinion.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is an overall side view of an electric assist bicycle according to a first embodiment of the present invention, and FIG. 2 is a side view showing a manner of mounting an electric assist drive unit. 3, FIG. 3 is a sectional view taken along the arrow B in FIG. 2, FIG. 4 is a sectional view taken along the line AA in FIG. 2, FIG. 5 is a sectional view in which the power transmission mechanism of the electric assist drive unit is developed, 6 is a sectional view taken along the line CC of FIG.

In the electric assist bicycle 1 shown in FIG. 1, an electric assist drive unit (hereinafter abbreviated as a drive unit) 10 is located in front of the hanger lug 4 of the bicycle main body 1A, and is arranged as shown in FIG. Mounted on bicycle body 1A. That is, the bicycle body 1A
The mounting member 14 is fixed to the diagonal frame 2 via a support plate 14a. The drive unit 10 is provided with a projection 41a on an upper portion of the speed reducer casing 41, and the support pin 15 is inserted into a hole formed in the projection 41a and a hole formed in the mounting member 14, whereby the bicycle body is 1A.

On the other hand, as shown in FIG. 4, the drive unit 10 is provided with fork-shaped support fittings 41c and 44a having semicircular concave tips on a reduction gear casing 41 and an inner wall 44 to be described later, respectively. , These support fittings 41
The tension of the chain 8 for transmitting the stepping force and the tension of the chain 13 for driving the rear wheel 17 are received by fitting the distal ends of the c and 44a to the outer peripheral surface of the hanger lug 4.

The pedal cranks 5 are respectively attached to both ends of a crankshaft 6 penetrating the hanger lug 4. A foot drive chain sprocket 7 is fixedly attached to one end of the crankshaft 6.
The chain 8 is wound around a chain sprocket 9 for taking the stepping drive force into the drive unit 10.

A drive chain sprocket 11 is mounted on the output shaft of the drive unit 10, and a driven chain sprocket 12 (see FIG. 1) is mounted on the shaft of the rear wheel 17 of the bicycle body 1A via a one-way clutch. ing. Both chain sprockets 11 and 12
, The chain 13 is wound around, so that power can be transmitted from the driving chain sprocket 11 to the driven chain sprocket 12. In addition, as shown in FIG. 1, a battery 77 for supplying electric power to the electric motor 31 is provided in an upper rear portion of the bicycle main body 1A.

The chain sprocket 9 and the driving sprocket 11 for taking in the stepping drive force into the drive unit 10
Are arranged concentrically and adjacently, so that the drive unit 10 can be configured to be small and compact while preventing interference between the sprockets 9 and 11.

The structure of the drive unit 10 will be described with reference to FIGS. The motor 31 includes a motor casing 38
And the inner wall 44. One end of the reduction gear casing 41 is integrally connected to the motor casing 38 with the middle wall 44 interposed therebetween, thereby forming a reduction gear casing.

The reduction gear casing 41 includes a two-stage gear reduction mechanism, a planetary gear mechanism described later, and one-way clutches 63 and 6.
4 and a later-described stepping torque detecting mechanism including a torque detecting arm 71, a potentiometer 72, and a compression spring 73. The motor 31 includes a stator 32 on which a coil is wound, and a rotor 34 on which a plurality of magnets 33 are attached at predetermined intervals along an inner peripheral surface facing the outer peripheral surface of the stator 32. This motor 31 has a so-called D
It is a C brushless motor, and a rotor 34 rotates by a rotating magnetic field generated when switching a coil current by a switching element such as a power transistor. The timing of the current sent to the coil is controlled by a Hall element or the like.

The first-stage large gear 51 (see FIG. 5)
The motor 31 is fixed to a rotating shaft 52 rotatably supported via a bearing on the casing 41 and meshes with a pinion 35 a formed at the tip of the rotating shaft 35 of the motor 31. On the rotation shaft 52 of the first-stage large gear 51, a small gear 52a that meshes with the second-stage large gear 53 is formed.
The second-stage large gear 53 is rotatably supported on a sun gear shaft 54, and transmits the forward driving force of the motor 31 to the output shaft 6.
1 to engage with the output shaft 61 via a one-way clutch 64. The pinion 35a, the first-stage large gear 5
1, the small gear 52a and the second-stage large gear 53 constitute a two-stage gear reduction mechanism. The hollow shaft portion of the second-stage large gear 53 concentrically located around the sun gear shaft 54 constitutes a reduction output shaft of the two-stage gear reduction mechanism. Through the output shaft 6
Engage with 1.

The planetary gear mechanism includes a sun gear shaft 54 disposed concentrically with a hollow output shaft 61, a sun gear 54a provided on the sun gear shaft 54, and a foot driven chain. An internal gear 56a directly connected to the sprocket 9,
Planetary gear carrier 57, sun gear 54a and internal gear 5
6a and a planetary gear 58 that rotates in a planetary manner. The planetary gear 58 is a planetary gear carrier 5
7 is supported via a pin 59.

The sun gear 54a is connected to the torque detecting arm 71
And rotates as a torque detecting means. The sun gear 54a is considered to have stopped rotating as an element of the power transmission planetary gear mechanism. Therefore, the planetary gear mechanism constitutes a reduction mechanism in which the internal gear 56a directly connected to the driven chain sprocket 9 that receives the stepping force is the driving side, and the reduced planetary gear carrier 57 is the output side.

A one-way clutch 63 is interposed between the planetary gear carrier 57 and the driven chain sprocket 11, and is engaged only when the bicycle 1 moves forward. A torque proportional to the stepping torque is transmitted to the sun gear shaft 54. Therefore, the compression spring 73 (see FIG. 6) interposed between the torque detection arm 71 fixed to the sun gear shaft 54 and the casing 41 works together with the potentiometer 72 for detecting the swing angle of the detection arm 71. It constitutes a pedal torque detection mechanism.

The output signal of the potentiometer 72 indicating the magnitude of the stepping torque is used as a function for controlling the output of the motor 31. An adjustment stopper 76 is screwed into a screw hole provided in the casing 41.
The adjustment stopper 76 adjusts the initial movement position of the detection arm 71 and applies an initial tension to the compression spring 73.

The rotational speed detecting sensor 74 attached to the casing 41 is a proximity sensor for detecting the teeth of a gear 61a provided on the output shaft 61. The rotational speed detection sensor 74 measures the output shaft rotational speed of the drive unit 10 by replacing the rotational speed with the number of teeth detected by the gear 61a in a unit time. Note that the rotation speed detection sensor 74 may be mounted at an appropriate location where the output shaft rotation speed of the drive unit or the running speed of the bicycle can be measured.

The operation of the bicycle 1 having the assist drive unit 10 will be described below with reference to FIG. 7, which shows a power transmission system and a control system of the bicycle 1. When the crankshaft 6 is rotationally driven manually by the pedal 16 and the pedal crank 5, the stepping torque is transmitted to the internal gear shaft 56 via the chain sprocket 7, the chain 8, and the chain sprocket 9.

Thus, the internal gear 56 of the planetary gear mechanism
a, the planetary gear 58 revolves around the fixed sun gear 54a, and as a result, the planetary gear carrier 57
Rotates. The rotation of the carrier 57 is controlled by the one-way clutch 6.
3, transmitted to the driving chain sprocket 11,
Further, the chain 13, the driven chain sprocket 12
Then, the rear wheel 17 is rotationally driven via a one-way clutch (not shown) provided on the rear wheel hub. When the driving chain sprocket 11 is rotated in the traveling direction of the bicycle with the crankshaft 6 stopped, the one-way clutch 63 does not engage and idles.

A torque proportional to the stepping torque is transmitted to the sun gear shaft 54. As described above, the initial pressure is applied to the compression spring 73 of the stepping torque detecting mechanism. Therefore, the potentiometer 72 of the stepping torque detecting mechanism sends an electric signal proportional to the stepping torque to the controller 75 when the stepping torque becomes equal to or more than a predetermined value set based on the initial pressure.

The controller 75 calculates an assist motor output torque corresponding to the stepping torque based on the stepping torque and a predetermined assist ratio (for example, 1). A power control circuit (not shown) built in the controller 75 controls the electric power supplied from the battery 77 so that the output of the motor 31 has a magnitude necessary for obtaining the motor output torque. 31. The rotation of the motor 31 is reduced to a required rotation by a two-stage gear reduction mechanism directly connected to the output shaft 35, and then transmitted to the driving chain sprocket 11 via the one-way clutch 64. Thus, the assist torque output from the drive mechanism of the motor 31 is added to the stepping torque.

When the bicycle 1 is driven only by the stepping force, the transmission of the stepping force to the motor 31 is interrupted by the one-way clutch 64.
The motor 31 does not become a load during the stepping operation.
Further, in a state where the bicycle 1 is driven while receiving the assist torque by the motor 31, when the speed of the bicycle 1 becomes equal to or higher than a preset speed, the motor 75 is stopped by the controller 75. The controller 7
5 judges that the speed of the bicycle 1 is over based on the output of the speed detection sensor 74.

In the electric assist bicycle 1 according to the first embodiment, the drive unit 10 is mounted on the frame 2 and the hanger lug 4 of the bicycle main body 1A by using the mounting member 14 and the support fittings 41c and 44a.
Further, the stepping force is applied to the drive unit 10 via the chain 8.
To the drive unit 1
After adjustment within 0, the rear wheel 1
7 is transmitted.

Therefore, according to the electric assist bicycle 1, the drive unit 10 can be attached to the bicycle main body 1A without modifying the normal specification bicycle main body 1A and without replacing basic parts of the bicycle main body 1A. Can be retrofitted. In addition, since standard components of a normal bicycle can be frequently used as functional components used for power transmission of the drive unit 10, cost reduction,
It is possible to improve the reliability and reduce the weight.

(Second Embodiment) The second embodiment is different from the first embodiment in the structure for attaching the drive unit to the bicycle main body 1A. That is, in the first embodiment, in order to attach the drive unit 10 to the bicycle main body 1A, one upper portion of the drive unit 10 is supported by the skewing frame 2 of the bicycle main body 1A via the support pins 15 and the attachment members 14. At the same time, the tips of a pair of fork-shaped support fittings 41c and 44a provided on the drive unit 10 are in contact with the outer peripheral surface of the hanger lug 4 of the bicycle body 1A.

On the other hand, in the second embodiment, as shown in FIG. 8, a unit mounting member 82 is fixed to the skew frame 2 and the saddle frame 3 of the bicycle body 1A, and The drive unit 80 is mounted in a pin joint type so that it can swing. Also, a take-up mechanism for adjusting the tension of the foot drive chain is added.

Hereinafter, the second embodiment will be described in more detail. Since the second embodiment and the first embodiment employ the same drive mechanism between the motor and the chain sprocket, the stepping torque detection mechanism, and the speed detection sensor in the drive unit, the following description will be made. A description thereof will be omitted. FIG. 8 is a side view showing a manner in which the electric assist drive unit 80 is attached to the bicycle main body 1A, and FIG. 9 is a view taken in the direction of arrow D in FIG.

In each figure, the drive unit 80 includes a mounting member 82 and a mounting member 83 substantially symmetrical to the mounting member 82.
And attached to the bicycle main body 1A. The mounting members 82 and 83 are opposed to each other so as to sandwich the skew frame 2 and the saddle frame 3 integrated with the hanger lug 4.
It is detachably fixed to the frames 2 and 3 by the fastening force of a plurality of bolts interposed between each other. The contact members 82a and 83 of the mounting members 82 and 83 are in pressure contact with the frames 2 and 3, respectively.

A pair of protrusions 81a and 81b are formed on the upper part of the casing 81 of the drive unit 80.
At the ends of the mounting members 82 and 83 on the side away from the hanger lug 4, a protrusion 82 a and a protrusion 83 a are provided, respectively.
Are formed. The drive unit 80 is rotatably supported by the mounting members 82 and 83 by inserting the pins 15 into the pin holes provided in the projections 81a, 81b and 82a and 83a, respectively.

An arm 82c protruding downward is formed at the end of the mounting member 82 on the hanger lug 4 side, and a projection 82d to which an adjustment screw 84 is screwed is formed at the tip of the arm 82c. I have. On the other hand, a contact plate 81d is provided on a projection 81c projecting obliquely downward from the casing 81, and the tip of the adjustment screw 84 is in contact with the contact plate 81d. The protruding portion 81c has a long hole 81e along the circumference centered on the pin 15, and the long hole 81e is provided.
The bolt 85 inserted in e is screwed into a screw hole provided at the tip of the arm 82c.

If the adjustment screw 84 is rotated with the bolt 85 loosened, the length of the adjustment screw 84 protruding from the projection 82d changes, and the drive unit 80
Rotate around a small angle around. Due to the rotational movement of the casing 81, the horizontal position of the drive unit 80 is adjusted, and as a result, the tension of the chain 8 that transmits the stepping force is adjusted. The adjusting screw 84 can be fixed to the projection 82d by a nut tightening operation. After the position adjustment of the drive unit 80 is completed,
The adjustment position of the drive unit 80 is maintained by tightening the bolt 85. Thus, the electric assist bicycle according to this embodiment has a take-up function of adjusting the tension of the chain 8.

In the electric assist bicycle according to the second embodiment, the drive unit 80 is attached to the frame 2 and the saddle frame 3 of the bicycle main body 1A by using attachment members 82 and 83. Further, the stepping force is transmitted to the drive unit 80 via the chain 8, and the assist driving force is transmitted to the rear wheel 17 via the chain 13 after being adjusted in the drive unit 80.

Therefore, according to the electric assist bicycle, the same effects as those of the first embodiment can be obtained. That is, the drive unit 80 can be retrofitted to the bicycle main body 1A without modifying the normal specification bicycle main body 1A and without replacing basic parts of the bicycle main body 1A. In addition, since standard components of a normal bicycle can be frequently used as functional components used for power transmission of the drive unit 80, cost reduction,
It is possible to improve the reliability and reduce the weight.

(Third Embodiment) The third embodiment differs from the first and second embodiments in the mounting structure of the drive unit to the bicycle main body and the structure of the stepping torque detecting and extracting mechanism. I have. That is, the third embodiment is common to the first embodiment in that the drive unit is supported by the pins at one position of the skewing frame 2. However, this embodiment differs from the first and second embodiments in the configuration (take-up mechanism) in which the horizontal position of the drive unit is adjusted by a pair of support fittings attached to the hanger lug 4.

Further, a base of the arm is mounted on a sun gear shaft capable of extracting a stepping torque, and a gear rack is provided at a tip end of the arm along a circumference centered on the sun gear axis, and the arm is controlled by the stepping torque. The present embodiment is different from the first and second embodiments in that a stepping torque detecting / extracting mechanism configured to transmit the rocking motion to the potentiometer through the rack and a pinion meshed with the rack is provided. A spring load proportional to the rotation angle is applied to the sun gear shaft via the arm.

Hereinafter, the third embodiment will be described in more detail. In the third embodiment and the first embodiment, the same drive mechanism between the motor and the chain sprocket in the drive unit and the same speed detection sensor are employed, so that the description thereof will be omitted below. I do.

FIG. 10 is a side view showing how the electric assist drive unit 90 is attached to the bicycle main body 1A, FIG. 11 is a rear view of FIG. 10, FIG. 12 is a sectional view taken along line E--E of FIG.
3 is a sectional view taken along line FF of FIG. In this embodiment,
Support brackets 88 and 89 are provided on the left and right sides of the bicycle main body 1A for supporting the drive unit 90 and adjusting the position in the horizontal direction, respectively.

The casing 91 of the drive unit 90 includes
An upper protrusion 91d having a mounting hole, and a protrusion chamber 91a for accommodating the pinion 94 of the stepping torque detecting mechanism.
(See FIG. 12). In the casing 91, a compression spring 96 (see FIG. 13), a spring support shaft 97 inserted into the compression spring 96, an inner protrusion 91b that slidably supports the support shaft 97, and a spring support shaft 97
Is provided.

On the outer surface of the casing 91, a female screw 91e (see FIG. 10) for mounting the support fitting 88 is provided, and a guide piece 91f for guiding the support fitting 88 in the horizontal direction is provided. The guide piece 91f is provided with a female screw hole 91g extending along the horizontal direction, and the adjusting screw 86 is screwed into the female screw hole 91g.

The inner wall 92 of the drive unit 90 shown in FIG.
Has substantially the same shape as the middle wall 44 (see FIG. 4) in the first embodiment. However, the middle wall 92 has a point at which the projecting portion 92a, which is a forming element of the projecting chamber 91a of the casing 91, is formed at the upper portion, and an extended wall 92b (see FIG. 11) for attaching the support member 89 in the lateral direction. This is different from the middle wall 44 in the first embodiment in the point.
The extension wall 92b is provided with a female screw 92c for attaching the support fitting 89.

As shown in FIG. 10, one end of the support bracket 88 has a semicircular concave edge 8 having the same diameter as the hanger lug 4.
8c is formed on the other end, and is parallelly extended in a fork shape in the horizontal direction and guided in the horizontal direction by the guide piece 91f provided in the casing 91.
A pair of arms 88d is formed. Each arm 8
8d is provided with a long hole 88a. The support bracket 88 extends rearward below a semicircular concave edge 88c to form a mounting hole at an end 88b of the extended portion. The supporting bracket 89 has a semicircular concave edge 89c having the same diameter as the hanger lug 4 and a pair of long holes 89a.
And a lower portion of the edge 89c is extended forward to form a mounting hole at the end 89b of the extension.

A mounting member 14 is fastened to the oblique pipe frame 2 integral with the hanger lug 4 by using a support plate 14a. The take-off drive unit 90 is pivotally supported by the frame 2 by passing the pin 15 through a hole provided in the mounting member 14 and a mounting hole provided in the upper protrusion 91 d of the casing 91.

The supporting brackets 88 and 89 have their semicircular concave edges 88c and 88c fitted and abutted on the front peripheral surface and the rear peripheral surface of the hanger lug 4, respectively, and their extended ends 88b and 89b have the following shapes. It is fastened together with a bolt to a mounting plate 87 fixed to a rear wheel support frame 18 extending rearward from the hanger lug 4. On the other hand, the support bracket 88 has the long hole 8.
8a into the female screw hole 91 of the casing 91.
e, screwed into the casing 91, and the support fitting 89 is used to screw a bolt inserted through the elongated hole 89a into a female screw hole 92c provided in the extension wall 92b of the middle wall 92. To the extension wall 92b.

The degree of tension of the chain 8 for transmitting the stepping force is determined by loosening the bolts attached to the long holes 88a, 89a of the support brackets 88, 89 and releasing the lock of the adjusting screw 86 to adjust the adjusting screw 86. Can be adjusted by executing the operation of turning. In other words, when the adjustment screw 86 is turned, the casing 91 is rotationally displaced about the pin 15 together with the chain sprocket 9, so that the chain 8
Can be adjusted. Thus, the support fitting 8
8, 89 are provided with a take-up function for adjusting the tension of the chain 8. When the tension adjustment of the chain 8 is completed, the adjusting screw 86 is locked with a lock nut, and the support brackets 88 and 89 are fixed with bolts.

Next, the stepping torque detecting mechanism will be described with reference to FIGS. The stepping torque detecting mechanism of the drive unit 90 rotates a rack arm 93 having a base end fixed to the sun gear shaft 54 and having a fan-shaped (arc-shaped) rack 93b formed on the outer peripheral end, and a pinion 94 meshing with the rack 93b. Potentiometer 95 fixed to shaft 95a
A support shaft 97 that abuts against the rack arm 93 to convert the rotational displacement of the arm 93 into a linear displacement; a compression spring 96 that biases the support shaft 97 toward the rack arm 93; and an initial position of the rack arm 93. An adjusting stopper 98 for defining the position and an adjusting stopper 91c for defining the displacement limit position of the support shaft 97.
And

The stepping torque is transmitted from the sun gear shaft 54 to the rack arm 93, and as a result, the rack arm 93
Rotates against the spring 96. Accordingly, the rack of the rack arm 93 rotates the potentiometer 95 via the pinion 94. The output signal of the potentiometer 95 is taken into the controller 75 shown in FIG. 7 as a signal indicating the stepping torque, and is used as a function for controlling the output of the motor 31. That is, the controller 75 sets the assist torque by executing a calculation of multiplying the stepping torque detected by the potentiometer 95 by a predetermined assist ratio (for example, 1), and sets the output of the motor 31 so that the assist torque is obtained. Control.

When a stepping torque is applied such that the assist torque reaches the allowable upper limit, the support shaft 97 comes into contact with the topper 91c. Therefore, further displacement of the rack arm 93 is prohibited, and rotation of the potentiometer 95 is also stopped. On the other hand, the rack arm 93
The initial position is set by the adjustment stopper 98 so that a predetermined initial compression force is applied to the compression spring 96. Therefore, while the stepping torque is small, the potentiometer 95 does not rotate, and therefore, no assist torque by the motor 31 is generated. Then, when the stepping torque increases to a magnitude corresponding to the initial compression force of the spring 96, the potentiometer 95 rotates and the assist torque by the motor 31 is generated. As described above, according to the stepping torque detection mechanism, the upper limit and the generation timing of the electric assist torque can be mechanically adjusted.

The drive unit 9 according to the third embodiment
The zero operation is basically the same as the operation of the drive unit 10 according to the first embodiment except for the operation of the stepping torque detection mechanism. Therefore, a block diagram showing a power transmission system and a control system of the bicycle 1 to which the drive unit 90 is applied is also represented as shown in FIG. However, the components of the stepping torque detection mechanism of the drive unit 10 are different from those of the stepping torque detection mechanism of the drive unit 10, and thus the components of the stepping torque detection mechanism of the drive unit 90 are shown in parentheses in FIG.

In the electric assist bicycle according to the third embodiment, the drive unit 90 is attached to the bicycle body by using the attachment member 14 and the support brackets 88 and 89. Further, the stepping force is transmitted to the drive unit 90 via the chain 8, and the assist driving force is adjusted in the drive unit 90 and then transmitted to the rear wheel 17 via the chain 13.

Therefore, according to this electric assist bicycle, the same effects as those of the first and second embodiments can be obtained. That is, the drive unit 90 can be retrofitted to the bicycle main body without modifying the bicycle main body of the normal specification and without replacing basic parts of the bicycle main body. The drive unit 90
Since standard components of ordinary bicycles can be frequently used as functional components used for power transmission of the vehicle, cost reduction, reliability improvement, and weight reduction can be achieved.

[0061]

According to the power assisted bicycle according to the first aspect, the drive unit 90 can be attached to the bicycle body without modifying the bicycle body of the normal specification and without replacing basic parts of the bicycle body. Can be retrofitted. Further, since standard components of a normal bicycle can be frequently used as functional components used for power transmission of the drive unit 90, cost reduction, reliability improvement, and weight reduction can be achieved. According to the electrically assisted bicycle according to the second aspect, the drive unit can be made compact. According to the electrically assisted bicycle according to the third aspect, the attachment operation of the electrically assisted drive unit is completed simply by attaching the upper part of the casing of the electrically assisted drive unit to the bicycle main body, so that the attachment operation is easy. According to the electrically assisted bicycle according to the fourth and fifth aspects, the tension of the second chain that transmits the power of the driving chain sprocket to the rear wheel of the bicycle body can be adjusted. According to the electric assist bicycle according to the sixth aspect, since the support means for supporting the electric assist drive unit is connected and fixed to the bicycle main body, the electric assist drive unit can be more stably mounted on the bicycle main body. According to the electric assist bicycle according to the seventh aspect, since the speed reduction means of the electric assist drive unit has a configuration in which the two-stage gear reduction mechanism and the planetary gear mechanism are combined, a sufficient reduction ratio can be obtained and the electric assist can be obtained. The drive unit can be made more compact. According to the electric assist bicycle according to the eighth aspect, since the stepping torque detecting means and the controller are housed in the casing of the electric assist drive unit, there is no one protruding around the unit. Therefore, the electric assist drive unit can be made more compact, and the weight distribution when the unit is mounted on the bicycle body is also improved. According to the electric assist bicycle according to the ninth and tenth aspects, the stepping torque can be detected by using the output of the sun gear shaft of the planetary gear mechanism, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view of an electric assist bicycle according to a first embodiment of the present invention.

FIG. 2 is a side view showing a mounting mode of the electric assist drive unit shown in FIG.

FIG. 3 is a view as seen in the direction of arrow B in FIG. 2;

FIG. 4 is a sectional view taken along line AA of FIG. 2;

FIG. 5 is an expanded sectional view of a power transmission mechanism of the drive unit of FIG. 2;

FIG. 6 is a sectional view taken along line CC of FIG. 4;

FIG. 7 is a block diagram showing a power transmission system and a control system of the electric assist bicycle using the drive unit shown in FIG. 2;

FIG. 8 is a side view showing a mounting mode of an electric assist drive unit in an electric assist bicycle according to a second embodiment of the present invention.

FIG. 9 is a view as viewed in the direction of arrow D in FIG. 8;

FIG. 10 is a side view showing a mounting state of an electric assist drive unit in an electric assist drive unit according to a third embodiment of the present invention.

11 is a rear view of the drive unit shown in FIG.

FIG. 12 is a sectional view taken along line EE of FIG. 10;

13 is a sectional view taken along line FF of FIG.

FIG. 14 is a side view showing an outline of a conventional auxiliary power unit.

FIG. 15 is a plan view of the auxiliary power unit shown in FIG. 14;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric assist bicycle 1A Bicycle main body 2 Diagonal frame 3 Saddle frame 4 Hanger lug 5 Pedal crank 6 Pedal crankshaft 7 Foot drive chain sprocket 8 Chain 9 Foot driven chain sprocket 10 Assist drive unit 11 Driven chain sprocket 12 Driven chain sprocket 13 Chain 14 Mounting member 17 Rear wheel 31 Motor 35 Motor shaft 35a Pinion 38 Motor casing 41 Casing 41c Fork-shaped support bracket 44 Middle wall 51 First stage large gear 52a Small gear 53 Second stage large gear 54 Sun gear shaft 54a Sun gear 56 Internal gear shaft 56a Internal gear 57 Planetary gear carrier 58 Planetary gear 63 One-way clutch 64 One-way clutch 71 Torque detection arm 72 Potentiometer 74 Speed sensor 75 Controller 80 Assist drive unit 82,83 Unit mounting member 86 Adjustment screw 88,89 Support bracket 90 Assist drive unit 91 Casing 92 Middle wall 93 Rack arm 94 Pinion 95 Potentiometer 96 Compression spring 98 Adjustment stopper

Claims (10)

[Claims] 1. A bicycle body having a foot drive chain sprocket rotated by a foot operation, and an electric assist drive unit attached to the bicycle body, wherein the electric assist drive unit is an electric motor, the foot drive A foot driven driven chain sprocket that takes in the power of the chain sprocket as stepping power via the first chain; and An electric assist bicycle, wherein power of the driving chain sprocket is transmitted to a rear wheel of the bicycle main body via a second chain. 2. The electric assist bicycle according to claim 1, wherein the step driven driven sprocket and the driven sprocket are arranged concentrically. 3. The electric assist drive unit is positioned in front of a hanger lug of the bicycle main body, and an upper portion of a casing of the electric assist drive unit is mounted on the bicycle main body. The electric assist bicycle according to claim 1 or 2, further comprising a support member that contacts and supports the casing. 4. An electric assist drive unit having a casing upper portion pivotally attached to an attachment member fixed to the bicycle body, and supporting the electric assist drive unit between the attachment member and the electric assist drive unit. A support means is interposed, and the support means has a take-up function of adjusting the tension of the second chain by swinging and displacing the electric assist drive unit around the pivoted portion. The electric assist bicycle according to claim 1 or 2, wherein 5. The electric assist drive unit is positioned in front of a hanger lug of the bicycle main body, and an upper part of a casing of the electric assist drive unit is pivotally attached to the bicycle main body. A take-up function for adjusting the tension of the second chain by swinging and displacing the electric assist drive unit about the pivoted portion, the supporting means being provided in contact with and supporting the casing; The electrically assisted bicycle according to claim 1, wherein the bicycle is provided with: 6. The electric assist bicycle according to claim 5, wherein said support means includes a connecting portion for connecting and fixing itself to said bicycle body. 7. The electric assist driving unit has a hollow deceleration output shaft, and is provided on a sun gear shaft concentric with the deceleration output shaft and rotatable, the deceleration mechanism being configured to reduce a rotation speed of the electric motor. A sun gear, an internal gear directly connected to the foot driven chain sprocket, and a planet gear supported by a planetary gear carrier and planetary rotating between the sun gear and the internal gear. A planetary gear mechanism, a first one-way clutch interposed between the speed reduction output shaft and the shaft of the driven chain sprocket, and engaged when the speed reduced output shaft drives the driven chain sprocket; A second gear carrier interposed between the gear carrier and the driving chain sprocket, wherein the planetary gear carrier is engaged when driving the driving chain sprocket. Includes the direction clutches, a motor-assisted bicycle according to any one of claims 1 to 6, characterized in that it has a structure that houses them to the casing. 8. A casing, comprising: a stepping torque detecting means for detecting a stepping torque; and a controller for controlling electric power supplied to the electric motor based on the stepping torque. Item 8. The electrically assisted bicycle according to item 7. 9. The stepping torque detecting means applies a torque proportional to a swing angle of the torque detecting arm to a torque detecting arm that swings with the rotation of the sun gear shaft. The electric assist bicycle according to claim 8, further comprising: a spring; and angle detecting means for detecting a swing angle of the torque detecting arm as a stepping torque. 10. The torque detection arm includes a fan-shaped rack along a circumference around a rotation axis of the torque detection arm, and the angle detection means includes a pinion meshed with the rack and a potentiometer linked to the pinion. The electric assist bicycle according to claim 9, wherein the bicycle is provided.