JP2003104267A - Body frame of scooter type motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a body frame of a scooter type motorcycle, wherein a pair of right and left brackets for supporting a power unit can be welded with good productivity. SOLUTION: Brackets 25 for supporting a power unit are provided at a pair of right and left backstays of a body frame 2. Cross members 43 for connecting both of the right and left brackets are laterally crosslinked between the brackets 25 for supporting the power unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a body frame of a scooter type motorcycle in which a front end portion of a unit swing type power unit is supported by a pair of left and right back stays.

[0002]

2. Description of the Related Art Conventionally, a body frame of a scooter type motorcycle has a down tube extending rearward and downward from a head pipe to a front portion of a footrest portion, and a pair of left and right back stays extending rearward from a rear end portion of the down tube. It has and. The back stay is bent rearward and upward at a rear portion of the footrest portion and extends from the bent portion to a rear portion of the vehicle body through a lower portion of the seat.

In the back stay, a power unit supporting bracket is welded in the vicinity of the bent portion, and a unit swing type power is attached via a link rotatably supported by the bracket with the vehicle width direction as the axial direction. It supports the front end of the unit. The rear end of the power unit is suspended from the rear end of the backstay via a cushion unit. In the connecting portion between the power unit supporting bracket and the link, a support shaft is inserted into a shaft hole formed in the bracket, and the support shaft supports a boss at the tip of the link via a damper rubber.

In order to weld the power unit supporting bracket to the back stay, the shaft holes of both brackets are positioned on the same axis parallel to the vehicle width direction so that the links can be accurately attached. The brackets (shaft holes) are positioned in the front-rear direction so that the unit can be mounted in the correct position. The positioning in the front-back direction is performed by moving the brackets so that the length from the head pipe to both brackets (shaft holes) matches the design value.

[0005]

However, the body frame of the conventional scooter type motorcycle constructed as described above has a positioning between the left and right brackets when welding the power unit supporting bracket to the back stay. Since it is necessary to position both of these brackets in the front-rear direction with respect to the back stay at the same time, there is a problem in that productivity is deteriorated because a special jig has to be used.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a body frame of a scooter type motorcycle capable of welding a pair of right and left power unit supporting brackets with high productivity. .

[0007]

In order to achieve this object, in a vehicle body frame of a scooter type motorcycle according to the present invention, a cross member for connecting left and right brackets to each other is horizontally mounted on a bracket for supporting a power unit. It is a thing. According to the present invention, an assembly is formed by connecting two brackets to each other with a cross member in a state where the power unit mounting portions are located on the same axis, and the assembly is formed to have a predetermined length from the head pipe. Further, the welding work of the two brackets is completed by positioning the two power unit mounting portions so as to be aligned in the vehicle width direction and welding them to the back stay. Therefore, it is possible to position the two brackets in advance,
Positioning in the front-rear direction with respect to the back stay can be performed when the bracket is welded.

A vehicle body frame for a scooter type motorcycle according to a second aspect of the present invention is the vehicle body frame for a scooter type motorcycle according to the first aspect,
A cross member is provided at a portion of the power unit supporting bracket near the power unit mounting portion. According to the present invention, the torsional rigidity of the power unit supporting bracket can be improved by the cross member.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a vehicle body frame of a scooter type motorcycle according to the present invention will be described in detail below with reference to FIGS. 1 is a side view of a scooter using a vehicle body frame according to the present invention, FIG. 2 is a side view of the vehicle body frame, FIG. 3 is a plan view of the vehicle body frame, FIG. 4 is a rear view of the vehicle body frame, and FIG. Enlarged side view,
6 is a sectional view taken along line VI-VI of the power unit supporting bracket and the front end portion of the link in FIG. 5, and FIG. 7 is a sectional view taken along line VII-VII of the rear end portion of the link and the compression bar in FIG.

In these figures, reference numeral 1 is a scooter type motorcycle according to this embodiment. This motorcycle 1 has a body frame 2 according to the present invention.
The unit swing type power unit 3 described later is mounted on the lower rear portion of the vehicle body frame 2 so as to be vertically swingable. In FIG. 1, reference numeral 4 indicates a front wheel, 5 indicates a front fork, 6 is a steering handle, 7 is a seat, 8 is a storage box, 9 is a rear wheel, and 1 is a rear wheel.
Reference numeral 0 indicates a vehicle body cover.

As shown in FIGS. 2 to 4, the body frame 2 includes a head pipe 11, a down tube 12 extending rearward and downward from the head pipe 11, and a connecting plate 13 to the down tube 12. A pair of left and right back stays 14 connected to each other and extending to the rear of the vehicle body,
15 and the first to fifth cross members 16 to 20 connecting the back stays 14 and 15 to each other. The pair of left and right back stays 14 and 15
Is a front portion 22 that extends rearward and upward substantially parallel to the footrest portion 21 (see FIG. 1) from the front end portion to a portion below the seat front portion in a side view, and the inclination angle with respect to the horizontal is larger than that of the front portion 22. As described above, the central portion 23 extends rearward and upward from the rear end of the front portion 22, and the rear portion 24 extends substantially parallel to the front portion 22 from the rear end of the central portion 23.

The front portions 22 of the back stay 14 on the left side of the vehicle body and the back stay 15 on the right side of the vehicle body are connected by the first to third cross members 16 to 18, and the rear portions 24 are connected to the fourth and fifth cross members. It is connected by members 19 and 20. The first cross member 16 has a central portion in the vehicle width direction welded to the down tube 12 and connects the down tube 12 and both backstays 14 and 15. The second cross member 17 connects the left and right backstays 14 and 15 at the rear end portion of the footrest portion 21. Further, the second cross member 17 is formed in a gate shape as shown in FIG. 3 in order to avoid interference with the engine of the power unit 3, and as shown in FIGS. 1 and 5,
It is provided so as to be inclined forward and upward in a side view.

The third cross member 18 is formed in a gate shape projecting upward, and the left and right back stays 14, 15 are formed.
The rear end portions of the front portion 22 are connected to each other, and the upper end portion supports the front end portion of the storage box 8.
Between the second cross member 17 and the third cross member 18 in the front portion 22 of the backstays 14 and 15, a power unit supporting bracket 25 for supporting the front end portion of the power unit 3 is provided downward. It is projected and welded. In FIG. 1, the front portion 2 of the back stays 14 and 15
Reference numeral 26 provided below 2 is a fuel tank. The fuel tank 26 is supported by the back stays 14 and 15 by a bracket (not shown), and an oil supply pipe 26 a is extended to the left side of the head pipe 11.

The fourth cross member 19 and the fifth cross member 20 connect the rear end portions of the rear portions 24 of the back stays 14 and 15 to each other. The fourth cross member 19 extends below the back stays 14 and 15 in the vehicle width direction. The fifth cross member 20 is formed in a gate shape and protrudes upward from the back stays 14 and 15, and the upper end portion supports the rear end portion of the storage box 8.
The storage box 8 has a structure in which the luggage entrance 8a at the upper end is opened and closed by the seat 7, and is formed with a capacity capable of accommodating a full-face helmet 27 and other luggage (not shown) as shown in FIG. ing.

The power unit 3 has the same structure as that well known in the prior art, and has a four-cycle single cylinder engine 31 and a crankcase 32 of the engine 31.
And a transmission device (not shown) housed inside the transmission case 33, and the like. In addition, as shown in FIG. 1, the power unit 3 has a front end portion (a lower front portion of the crankcase 32).
Is supported by the power unit supporting bracket 25 of the back stays 14 and 15 in a vertically swingable manner by a link 34, and a rear end portion (a rear end portion of the transmission case 33) is supported by a cushion unit 35 on the left side of the vehicle body. It is suspended at the rear end of the stay 14. Link 3
Between the power unit side end of 4 and the body frame 2,
The compression bar 36 is provided to prevent the front portion of the power unit 3 from moving upward with respect to the body frame 2.

The engine 31 of the power unit 3 is formed so that the axis line of the cylinder 37 is directed toward the front of the vehicle body, and the cylinder 37 is formed in the back stay 1 of the vehicle body frame 2.
It faces between 4 and 15. The cylinder 37 has an intake pipe 38 connected to an upper portion thereof and an exhaust pipe (not shown) connected to a lower portion thereof. The carburetor 3 is installed in the intake pipe 38.
9, and an air cleaner 40 is connected to the carburetor 39.

Here, the structure of the connecting portion between the front end of the power unit 3 and the vehicle body frame 2 will be described in more detail with reference to FIGS. As shown in FIG. 6, the power unit supporting bracket 25 is formed by welding together an outer plate 41 located outside the vehicle body and an inner plate 42 located inside the vehicle body. Further, the bracket 25 provided on the backstay 14 on the left side of the vehicle body and the bracket 25 provided on the backstay on the right side of the vehicle body are connected to each other by the bracket cross member 43, and are connected to the backstays 14 and 15 in a state of forming one assembly. We are welding.

The cross member 43 is formed in a U shape in a downward cross section, and both ends thereof are welded to the inner plates 42 of both brackets 25, respectively. Also, both brackets 25
As shown in FIG. 5, an auxiliary bracket 44 is provided at the rear end portion for attaching the upper end portion of the compression bar 36. As shown in FIGS. 4 and 7, the auxiliary bracket 44 has an outer plate 44a integrally formed with the outer plate 41 of the power unit supporting bracket 25.
And an inner plate 44b integrally formed with the inner plate 42 of the power unit supporting bracket 25.

As shown in FIGS. 5 and 6, the link 34 is welded to the front link 45 connected to the power unit supporting bracket 25 and the center portion of the front link 45 in the vehicle width direction. It is configured by a rear link 46 that connects the power unit 3 to the rear end. The front link 45 is formed by welding a boss 45b to the front end of a U-shaped pipe 45a that is open toward the front in plan view. The boss 45b is fitted with a connecting member having an inner cylinder 47 and an outer cylinder 48 that are connected to each other via a damper rubber 45c.

The inner cylinder 47 of this connecting member is fitted with a supporting bolt 49 provided so as to extend toward the inside of the vehicle body on the inner plate 42 of the power unit supporting bracket 25. The plate 42 is fastened to the inner end surface of the vehicle body. The supporting bolt 49
Is inserted into the bolt hole 42a of the inner plate 42 from the outside of the vehicle body through the through hole 41a formed in the outer plate 41. The bolt hole 42a constitutes a power unit mounting portion of the power unit supporting bracket according to the present invention. The bolt hole 42a is formed near the rear of the cross member 43 that connects the brackets 25 to each other.

Bosses 45b, 45b at both ends of the front portion 22
Of the bosses 45 on the right side of the vehicle body, as shown in FIGS. 5 and 6, when the lower end portion of the compression bar 36 is removed from the link 34 and the power unit 3 moves upward with respect to the vehicle body frame 2. A stopper 50 is provided in order to restrict the further upward movement of the power unit 3. The stopper 50 is formed of a plate material, one end of which is welded to the outer periphery of the boss 45b, and the other end of which is projected from the boss 45b toward the front of the vehicle body so as to face above the cross member 43.

The rear link 46 of the link 34 is formed by welding a tubular member 46b to the rear end of the connecting member 46a extending rearward from the pipe 45a of the front link 45. As shown in FIG. 7, the tubular member 46 b supports the connecting bolt 51 in a penetrating state, and the two connecting plates 52 of the power unit 3 and the compression bar 36 are supported via the connecting bolt 51. Is connected to the lower end portion (end portion on the power unit 3 side) of. The connecting plate 52 is formed integrally with the crankcase 32, and
It is rotatably supported by the connecting bolt 51 via the connector 3.

The lower end of the compression bar 36 is elastically supported by the connecting bolt 51 via a boss 36a equivalent to the boss 45b of the front link 45 and a connecting member. Reference numeral 54 denotes an inner cylinder of a connecting member provided in the boss 36a, 55 denotes an outer cylinder, and 56 denotes a damper rubber. Upper end of the compression bar 36 (end on the body frame 2 side)
Adopting the same structure as the lower end, the inner cylinder 57 on the boss 36b,
A connecting member having an outer cylinder 58 and a damper rubber 59 is provided, and is supported by the auxiliary bracket 44 via the boss 36b and the connecting member. The inner cylinder 57 is fastened to the auxiliary bracket 44 by a supporting bolt 60.

By thus supporting the front end of the power unit 3 on the vehicle body frame 2 by the link 34 and the compression bar 36, the front end of the power unit 3 is deformed by the elastic deformation of the damper rubbers 45c, 56, 59. The frame 2 can be rotated in the vertical direction.

In order to weld the power unit supporting bracket 25 to the back stays 14 and 15, first, the bracket 25 on the left side of the vehicle body and the bracket 25 on the right side of the vehicle body are connected to each other by a cross member 43, and the bracket assembly is assembled. Form. The welding of the cross member 43 is performed such that the bolt hole 42a of the bracket 25 on the left side of the vehicle body and the bolt hole 42a of the bracket 25 on the right side of the vehicle body are located on the same axis, and the angle (inclination) of both brackets 25 in a side view. ) Are matched. That is, the positioning between the left and right brackets 25 is performed in this step. Next, the bracket assembly is temporarily placed below the front portions 22 of the back stays 14 and 15 by using a jig or the like (not shown), and the length from the head pipe 11 becomes a predetermined length and at two positions. The bolt holes 42a, 42a are positioned so as to be aligned in the vehicle width direction and welded to the back stays 14, 15. In this process, both brackets 25 are positioned in the front-rear direction.

Therefore, according to the vehicle body frame 2 according to this embodiment, the positioning between the two brackets 25 can be performed in advance, and the back stays 14 and 15 can be positioned.
Since the positioning in the front-rear direction can be performed when the bracket 25 is welded, the bracket 25 can be welded to the vehicle body frame 2 easily and accurately. Further, since the cross member 43 is provided at a portion of the power unit supporting bracket 25 close to the bolt hole 42a, the torsion rigidity of the bracket 25 can be improved by the cross member 43.

[0027]

As described above, according to the present invention, the positioning between the two brackets can be performed in advance, and the positioning in the front-rear direction with respect to the back stay can be performed when the brackets are welded. The productivity can be improved as compared with the conventional body frame in which two types of positioning are simultaneously performed and welding is performed.

According to the second aspect of the present invention, since the cross member improves the torsional rigidity of the power unit supporting bracket, it is possible to provide the vehicle body frame of the scooter type motorcycle which can firmly support the power unit.

[Brief description of drawings]

FIG. 1 is a side view of a scooter using a vehicle body frame according to the present invention.

FIG. 2 is a side view of a body frame.

FIG. 3 is a plan view of a body frame.

FIG. 4 is a rear view of the body frame.

FIG. 5 is a side view showing an enlarged main part.

6 is a sectional view taken along line VI-VI of the front end portion of the power unit supporting bracket and the link in FIG.

7 is a sectional view of the rear end portion of the link and the compression bar in FIG. 5, taken along line VII-VII.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scooter type motorcycle, 2 ... Body frame, 3 ... Unit swing type power unit, 14, 15 ... Back stay, 21 ... Foot rest part, 25 ... Power unit supporting bracket, 42a ... Bolt hole, 43 ... Cross member .

Claims (2)

[Claims] 1. A scooter type motorcycle comprising a pair of left and right back stays extending rearward and upward from a footrest portion, and a power unit supporting bracket for supporting a front end portion of a unit swing type power unit, each of which is welded to the back stay. A body frame of a scooter type motorcycle, wherein a cross member for connecting the brackets to each other is horizontally mounted on the bracket. 2. The vehicle body frame of the scooter type motorcycle according to claim 1, wherein a cross member is provided at a portion of the power unit supporting bracket near the power unit mounting portion.