JP2000168663A - Car body frame of electric auxiliary bicycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce manufacturing cost and to make a car body frame high in precision, light and high in rigidity by fixing an electric power unit on a curved-in part and placing a battery unit for an electric power source on a horizontal plate. SOLUTION: A bracket 7 is formed so as to be furnished with a flat horizontal plate 8 extending horizontally in the longitudinal direction of a car body and a pair of left and right vertical plates 9 bent downward from both left and right edges of this horizontal plate 8 by bending and molding a plate material and has a cross-section of a square shape with one side open to open downward as seen in the longitudinal direction. Additionally, small holes 11 are drilled in the front and the rear of the horizontal plate 8, and a nut 12 is fastened from its back surface side. Additionally, curved-in parts 13 to be curved in from below upward are respectively formed on the left and right vertical plates 9. Furthermore, connecting sides 15, 16a, 16b along a central shaft of a down pipe 4 and a seat pipe 6 are formed on front end parts and rear end parts of the horizontal plates 9, and the connecting side 15 is welded on the down pipe 4 and the connecting sides 16a, 16b are welded on the seat pipe 6 respectively. Thereafter, an electric power unit 42 and a battery unit 43 are set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric assisted bicycle which combines a pedal depression force of an occupant with a driving assist force of an electric motor and transmits the resultant to driving wheels, thereby reducing a pedal depression force to facilitate running. It relates to a body frame.

[0002]

2. Description of the Related Art In this type of electric assist bicycle, an electric power unit including an electric motor, a resultant device, a controller and the like is installed on a body frame. An example of a general structure of the vehicle body frame is described in, for example, Japanese Patent Application Laid-Open No. 9-207859. In this vehicle, a sheet metal bracket is provided near an intersection of a down pipe extending obliquely rearward and downward from a head pipe of a body frame and a seat pipe supporting a saddle, and an electric power unit is fixed to the bracket.

[0003] The bracket has a curved back surface, and is formed to cover the upper part of the electric power unit when viewed from the side. The lower end of the down pipe and the lower end of the seat pipe are attached to two front and rear cylindrical mounting holes formed on the back surface of the bracket. Inserted and joined. The front ends of a pair of left and right chain stays are bolted to the rear of the bracket. By fixing the electric power unit to the bracket, the rigidity of the bracket is greatly increased, and the electric power unit itself is used as a strength member of the vehicle body frame.

[0004]

However, like the above-described vehicle body frame, the rear surface of the bracket is curved to form the electric power unit so as to surround the electric power unit from above, and the cylindrical shape for inserting the down pipe and the seat pipe is formed. In order to provide the mounting port, a sheet metal material is drawn using a large-sized press to manufacture a bracket, and the manufacturing process becomes complicated and difficult. For this reason, the yield of the bracket is reduced, and a large production cost is required including the equipment cost of the press machine and the press die. Moreover,
It is difficult to maintain good bracket accuracy.

In the vehicle body frame having the above structure, the seat pipe and the chain stay are connected to each other through the bracket made of sheet metal. Therefore, the rigidity of the frame, especially the lateral rigidity and the torsional rigidity, is weak, and the cost for reinforcing the rigidity is low. Hangs,
This also leads to an increase in the weight of the body frame.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a highly accurate, lightweight, and highly rigid body frame of an electric assisted bicycle that is easy to manufacture, has low manufacturing cost, and is low in cost. The purpose is to:

[0007]

According to a first aspect of the present invention, there is provided a body frame of a battery-assisted bicycle according to the present invention, wherein the down pipe extends obliquely rearward and downward from a head pipe of the body frame. In the body frame of the battery-assisted bicycle, the lower end of the seat is connected with a lower end of the seat pipe supporting the saddle by a sheet metal bracket, and the electric power unit is fixed to the bracket.
A pair of right and left vertical plates having a flat horizontal plate extending horizontally in the longitudinal direction of the vehicle body, and a bent portion bent downward from both left and right edges of the horizontal plate and bent upward from below in a side view. With a U-shaped cross section that opens downward as viewed in the front-rear direction, an electric power unit is fixed to the indentation, and a battery unit for power supply is mounted on a horizontal plate. It is characterized by the following.

According to a second aspect of the present invention, there is provided a vehicle body frame for an electric assisted bicycle, comprising a bridge extending in the vehicle width direction at a front end of a pair of left and right chain stays extending rearward from a vicinity of a lower end of the seat pipe. It is joined to the pipe and formed in a torii shape in plan view, and the bridge pipe is joined near the lower end of the seat pipe, and the rear end of the bracket is straddled near the lower end of the seat pipe and the bridge pipe. Joined.

Further, in the vehicle body frame of the electric assisted bicycle according to the present invention, the down pipe and the seat pipe of the down pipe and the seat pipe are respectively provided at the front and rear ends of the left and right vertical plates of the bracket. Joining sides along the central axis were formed, and these joining sides were joined to the down pipe and the sheet pipe.

According to the first aspect of the present invention, since the folding frame between the horizontal plate and the left and right vertical plates of the bracket is straight, the bracket can be easily formed without depending on the drawing process. Can be manufactured. Therefore, it is possible to significantly reduce the manufacturing cost and improve the accuracy of the body frame.

Further, according to the vehicle body frame of the electric assisted bicycle, the left and right chain stays are joined near the lower end of the seat pipe via the bridge pipe, and the joint is reinforced by the bracket. Therefore, the rigidity of the vehicle body frame is improved, and it is not necessary to provide another reinforcing member, so that it is possible to contribute to a reduction in manufacturing cost and weight of the vehicle body frame.

Further, when the vehicle body frame of the electrically assisted bicycle is configured as in claim 3, the joint length between the bracket, the down pipe, and the seat pipe can be increased, so that the rigidity of the vehicle body frame can be further improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a left side view showing an example of an electric assisted bicycle including a body frame according to the present invention, and FIG. 2 is a left side view of a body frame alone. FIG. 3 is an enlarged view of a portion III in FIG. 2, and FIGS. 4 and 5 are cross-sectional views taken along lines IV-IV and VV in FIG. 3, respectively.

The body frame 2 of the electric assist bicycle 1
A straight down pipe 4 extends obliquely rearward and downward from a head pipe 3 located at the forehead, while a seat pipe 6 supporting a saddle 5 extends in a vertical direction, and the lower end of the down pipe 4 and the seat pipe 6 Are connected to each other by a bracket 7 made of sheet metal.

The bracket 7 is formed by bending a sheet metal material to form a flat horizontal plate 8 extending horizontally in the longitudinal direction of the vehicle body, and a pair of left and right vertical plates 9 bent downward from both left and right edges of the horizontal plate 8. And has a U-shaped cross section that opens downward when viewed in the front-rear direction (see FIG. 4).
A small hole 11 is formed before and after the horizontal plate 8, and a nut 12 is fixed at that position from the back side. In addition, the left and right vertical plates 9 are each formed with an indentation portion 13 which indents from below to above in a side view, and two bolt holes 14 are provided before and after the indentation portion 13 in total. .

Further, the front and rear ends of the left and right vertical plates 9 of the bracket 7 have down pipes 4 in side view, respectively.
Sides 15, 16a, 16b along the central axis of the sheet pipe 6
Are formed linearly and the front joining side 15 is
Then, the rear joining sides 16a and 16b are joined to the seat pipe 6 by welding or the like. Note that the rear joining side 16
a and 16b are formed in two upper and lower parts and formed in opposite directions, and a slit 17 is formed along the center axis of the sheet pipe 6 between them, and the slit 17 is also formed on the upper and lower joining sides 16a and 16b. Is joined to the seat pipe 6 in the same manner as described above.

A pair of left and right chain stays 19 extend rearward from the vicinity of the lower end of the seat pipe 6. The front ends of these chain stays 19 are abutted and joined to a short bridge pipe 20 extending in the vehicle width direction. As shown in FIG. 5, it is formed in a torii shape in plan view. As shown in FIG. 6, a bridge recess 20 formed on the rear side near the lower end of the seat pipe 6 and a pair of right and left R-shaped cutouts 22 formed on the lower rear of the bracket 7 are provided with a bridge pipe 20. Are fitted and joined.

As described above, the rear end of the bracket 7 is joined to the vicinity of the lower end of the seat pipe 6 at the joints 15, 16a, 16b and the slit 17, and the bridge pipe 20 is formed at the notch 22. The bracket 7
Is fixed so as to straddle the sheet pipe 6 and the bridge pipe 20. Below the notch 22, a pair of left and right fixing pieces 23 are formed which are bent outward in the vehicle width direction and extend along the axial direction of the bridge pipe 20, and the upper edge of the fixing piece 23 is also formed on the bridge pipe 20. Joined.

As shown in FIG. 2, the rear ends of a pair of left and right chain stays 19 and the lower ends of a pair of left and right seat stays 25 extending obliquely downward and rearward from near the upper end of the seat pipe 6 are respectively attached to end plates 26. Joined. A battery holder 27 is fixed at a position slightly above the bracket 7 on the front surface of the seat pipe 6, and between the vicinity of the front ends of the left and right chain stays 19 and the vicinity of the upper ends of the left and right seat stays 25. Rear fender fixing plates 28 and 29 are installed.

In the body frame 2 constructed as described above, a front fork 31 is pivotally supported on the head pipe 3 so as to be rotatable left and right, and a front wheel 32 is pivotally supported at the lower end thereof. A handlebar 34, a front fender 35, a basket 36 and the like are provided so as to rotate integrally.
On the other hand, a rear wheel 37 is pivotally supported on the end plate 26 of the body frame 2, and a rear fender 38 and a rear carrier 39 covering the rear wheel 37 are provided on the rear fender fixing plates 28 and 29 and the end plates.
26, fixed near the upper end of the seat pipe 6. Also,
The saddle 5 is installed at the upper end of the seat pipe 6 via a saddle post 40.

As shown in FIG. 7, an electric power unit 42 and a battery unit 43 are installed on the bracket 7 of the vehicle body frame 2. As will be described in detail below, the electric power unit 42 is disposed in the indentation 13 formed in the left and right vertical plates 9 of the bracket 7, and the battery unit 43 is detachably mounted on the horizontal plate 8 of the bracket 7. .

The electric power unit 42 includes a casing 44 made of an aluminum alloy or the like, in which devices such as an electric motor 45, a resultant device 46, and a controller (not shown) shown in FIG. The four fixed pedestals 48 (see FIG. 7) are respectively sandwiched between the left and right vertical plates 9 of the bracket 7. Each fixing pedestal 48 is aligned with the position of the bolt hole 14 formed in the vertical plate 9 and
The fixing bolt 49 penetrates the bolt hole 14 and the fixing pedestal 48 in the vehicle width direction and a nut (not shown) is fastened from the opposite side, whereby the electric power unit 42 is fixed to the bracket 7. When the electric power unit 42 is fixed to the bracket 7, the rigidity of the bracket 7 is dramatically increased, and as a result, the rigidity of the entire body frame 2 is improved.

Then, a unit cover 50 made of synthetic resin is provided so as to cover the bracket 7 and the electric power unit 42. As shown in FIG. 7, a battery unit formed in a substantially rectangular parallelepiped shape is provided on an upper portion of the unit cover 50.
A battery recess 51 into which the battery 43 can be fitted is formed. The battery recess 51 is located at the lowest position between the down pipe 4 and the seat pipe 6 of the body frame 2 and has a bottom surface.
Two front and rear fastening pedestals 53 recessed in 52 are fastened by screws 54 to the nuts 12 provided on the back surface of the horizontal plate 8 of the bracket 7. The rear lower part of the unit cover 50 is fastened to the fixing piece 23 of the bracket 7 by a screw (not shown).

The battery unit 43 has a waterproof structure in which a battery 57 is housed in a battery case 56 made of synthetic resin. The battery case 56 is detachably fixed to the battery recess 51. For example, an engagement projection 58 protruding from the front surface of the battery case 56 is fitted into an engagement hole 59 formed on the front surface of the battery concave portion 51, and a locking portion (not shown) provided on the rear surface of the battery case 56. Is locked by a lock mechanism (not shown) provided on the battery holder 27 of the seat pipe 6. The lock mechanism is configured to be unlocked only by a specific key, thereby preventing the battery unit 43 from being stolen. The battery case
A carrying handle 60 (see FIG. 1) is provided on the upper surface of 56.

The crankshaft 63 is rotatably supported by the electric power unit 42 at the portion of the resultant device 46 in the vehicle width direction. Cranks 64 are fixed to both ends of the crankshaft 63 so as to rotate integrally therewith, and a pedal 65 is rotatably provided at the tip of each crank 64. Also, the crankshaft
A drive sprocket (not shown) located on the right side of the electric power unit 42 is mounted on the shaft 63. A chain is provided between the drive sprocket and a driven sprocket (not shown) provided on the right side of a hub (not shown) of the rear wheel 37. 66 is wound.

The crankshaft 63 is driven to rotate in the direction A by the occupant sitting on the saddle 5 depressing the pedal 65 with both feet.
45 is activated, and the rotational force of the crankshaft 63 (pedal force)
The output (drive assist force) of the electric motor 45 is combined with the resultant device 46, and the resultant force rotates the drive sprocket in the direction A, and this rotation is transmitted to the driven sprocket via the chain 66, and the rear wheel 37 is driven. Is done.

As described above, since the occupant's pedal depression force is assisted by the driving assist force of the electric motor 45, the burden on the occupant is reduced, and traveling is facilitated. The magnitude of the driving assist force is appropriately adjusted by a controller built in the electric power unit 42 in accordance with the pedaling force.

The body frame 2 of the electric assist bicycle 1
As described above, the bracket 7 is formed to have a U-shaped cross section including a flat horizontal plate 8 and a vertical plate 9 bent downward from both left and right edges thereof.
Since the fold curve between the vertical plate 9 and the vertical plate 9 is straight, the bracket 7 can be easily manufactured only by bending the sheet metal material.

Therefore, unlike the conventional case, there is no need to manufacture the bracket 7 by drawing, so that equipment such as a large press machine and a complicated press die is not required, and the process of machining the bracket 7 itself is greatly simplified. Therefore, it is possible to greatly contribute to reducing the manufacturing cost and improving the accuracy of the body frame 2. Since the electric power unit 42 is fixed to the indentation 13 formed on the left and right vertical plates 9 of the bracket 7, the bending rigidity and the torsional rigidity of the bracket 7 are dramatically increased by the electric power unit 42 itself.

In the vehicle body frame 2, the front ends of the left and right chain stays 19 are joined to the bridge pipe 20 to form a torii gate.
And the rear end (16a, 16b, 17, 22, 23) of the bracket 7 is joined so as to straddle the vicinity of the lower end of the seat pipe 6 and the bridge pipe 20. Therefore, the vicinity of the joint between the chain stay 19 and the seat pipe 6 is reinforced by the bracket 7, and the rigidity of the vehicle body frame 2 is significantly improved. In addition, since it is not necessary to provide another reinforcing member near the joint by the bracket 7, it is possible to reduce the manufacturing cost and the weight by reducing the number of parts of the body frame 2.

Furthermore, the joining sides 15, 16a, 16b (17) formed at the front and rear ends of the left and right vertical plates 9 of the bracket 7 are:
It is along the central axis of the down pipe 4 and the seat pipe 6 in a side view, and since these joining sides 15, 16a, 16b (17) are joined to the down pipe 4 and the seat pipe 6, the bracket 7 (vertical plate) 9) and a long joining length between the down pipe 4 and the seat pipe 6 can be ensured. Therefore, the rigidity of the body frame 2 can be further increased.

In the present embodiment, the front joining side 15 and the rear upper joining side 16a of the bracket 7 are extended upward to be higher than the horizontal plate 8, so that the joining length is maximized. Has been extended. In the present embodiment, the front and rear edges of the horizontal plate 8 are separated from the down pipe 4 and the seat pipe 6, but if this portion is also joined to the down pipe 4 and the seat pipe 6, the joining strength can be further increased. Can be.

When assembling the body frame 2, a front assembly in which the head pipe 3 and the down pipe 4 are previously assembled, and a rear assembly in which the seat pipe 6, the chain stay 19, the bridge pipe 20, and the seat stay 25 are assembled. It is only necessary to manufacture the assembly and connect the front and rear assemblies with the bracket 7, so that the number of assembling steps of the entire body frame 2 can be simplified, and this also contributes to the reduction of the manufacturing cost and the accuracy of the body frame 2. be able to.

Further, in the vehicle body frame 2, the battery unit 43 is mounted on the horizontal plate 8 of the bracket 7, so that the battery unit 43 can be installed very stably. Is installed at a low position, the center of gravity of the battery-assisted bicycle 1 is lowered to improve running stability, and the body frame 2
It is easy to straddle, and the rideability can be improved.

[0035]

As described above, the body frame of the battery-assisted bicycle according to the present invention connects the lower end of the down pipe and the lower end of the seat pipe to each other, and includes the sheet metal bracket on which the electric power unit is installed. A flat horizontal plate extending horizontally in the front-rear direction of the vehicle body, and a pair of right and left vertical plates having a bent portion bent downward from both left and right edges of the horizontal plate and bent upward from below in a side view. And has a U-shaped cross section that opens downward when viewed in the front-rear direction.The electric power unit is fixed to the indentation, and the battery unit for power supply is mounted on the horizontal plate. According to this, since the bracket can be easily manufactured without depending on the drawing process, the manufacturing cost of the body frame can be reduced and the body frame can be reduced. It is possible to improve the accuracy.

Further, in the vehicle body frame of the electric assisted bicycle according to the present invention, the front ends of a pair of left and right chain stays extending rearward from the vicinity of the lower end of the seat pipe are joined to a bridge pipe extending in the vehicle width direction, and the torii gate is viewed in plan. Formed into a shape
The bridge pipe was joined near the lower end of the seat pipe, and the rear end of the bracket was joined so as to straddle the lower end of the seat pipe and the bridge pipe. The joint of the body frame and the bracket is reinforced with a bracket to improve the rigidity of the body frame, and other reinforcing members can be omitted to reduce the manufacturing cost and weight of the body frame.

Further, in the vehicle body frame of the electric assisted bicycle according to the present invention, joint sides along the central axes of the down pipe and the seat pipe are formed at the front and rear ends of the left and right vertical plates of the bracket, respectively, in a side view. Since these joining sides are joined to the down pipe and the seat pipe, the joining length between the bracket, the down pipe and the seat pipe can be secured long, and the rigidity of the body frame can be further improved.

[Brief description of the drawings]

FIG. 1 is a left side view showing an example of an electric assist bicycle including a vehicle body frame according to the present invention.

FIG. 2 is a left side view of the vehicle body frame alone.

FIG. 3 is an enlarged view of a part III in FIG. 2;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

FIG. 5 is a sectional view taken along the line VV of FIG. 3;

FIG. 6 is a left side view showing a state before joining of a seat pipe, a bridge pipe, and a bracket.

FIG. 7 is an enlarged left side view showing a state in which the electric power unit, the battery unit, and the unit cover are mounted on the bracket, and is a view showing one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric assist bicycle 2 Body frame 3 Head pipe 4 Down pipe 5 Saddle 6 Seat pipe 7 Bracket 8 Horizontal plate 9 Vertical plate 13 Bay entrance 15, 16a, 16b Joining side 19 Chain stay 20 Bridge pipe 25 Seat stay 42 Electric power unit 43 Battery unit

Claims (3)

[Claims] 1. A lower end of a down pipe extending obliquely rearward and downward from a head pipe of a vehicle body frame and a lower end of a seat pipe supporting a saddle are connected by a sheet metal bracket, and an electric power unit is fixed to the bracket. In the body frame of the electric assisted bicycle, the bracket 7 is attached to a flat horizontal plate 8 extending horizontally in the vehicle front-rear direction.
And a pair of right and left vertical plates 9 having bent portions 13 that bend downward from both left and right edges of the horizontal plate 8 and bulge upward from below in a side view, and open downward in a front-rear direction. It is formed to have a U-shaped cross section, and
An electric power unit 42 is fixed to the vehicle body frame, and a battery unit 43 for power supply is mounted on the horizontal plate 8. 2. A front end of a pair of left and right chain stays 19 extending rearward from near the lower end of the seat pipe 6 is joined to a bridge pipe 20 extending in the vehicle width direction to form a torii gate in plan view. 2. The body of the electrically assisted bicycle according to claim 1, wherein the rear end of the bracket 7 is joined so as to straddle the vicinity of the lower end of the seat pipe 6 and the bridge pipe 20. flame. 3. At the front and rear ends of the left and right vertical plates 9 of the bracket 7, joining sides 15, 16a, 16b are formed along the central axis of the down pipe 4 and the seat pipe 6 in side view, respectively. The body frame of the electric assist bicycle according to claim 1, wherein the joining sides (15, 16a, 16b) are joined to the down pipe (4) and the seat pipe (6).