JPH048077Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to an improvement in the frame structure of a small vehicle having a low footrest, such as a scooter type motorcycle or a small three-wheeled motor vehicle.

(Prior art) The conventional frame structure of a small vehicle having this type of low-floor footrest is, for example,
As shown in No. 42776, the body frame of the motorcycle is composed of one down tube connected to a head pipe and a pair of substantially parallel left and right back stays whose front ends are connected to the lower end of this down tube. The front part of the backstay is a horizontally extending footrest floor support part, the middle part is a seat post part rising rearward and upward, and the rear part is a seat rail part extending rearward. The connection structure between the down tube and the back stay is such that the lower end of the down tube is bent toward the rear of the vehicle body, and the front ends of the left and right back stays are bent inward so as to approach each other. These are welded to the left and right sides of the bottom end of the tube.

On the other hand, the connection structure between the down tube and the back stay in the frame structure of a motorcycle shown in JP-A No. 57-114776 is such that the front ends of the left and right back stays are not bent inward but are extended toward the front of the vehicle body. They are arranged in parallel and spaced apart on both the left and right sides of the lower end of the down tube, and the front end of the backstay and the lower end of the down tube are welded via gussets, respectively.

However, in any of the above frame structures, the lower end of the down tube and the front end of the backstay are connected in a straight line when viewed from the side of the vehicle, that is, in a planar manner. By ensuring rigidity and rigidity against bending and torsion, the vehicle body frame becomes heavier.

(Purpose of the invention) The present invention was made to effectively solve the above-mentioned problems in the frame structure of a small vehicle having a low footrest floor. We aim to improve the joint strength between the down tube and the pair of left and right backstays,
To provide a frame structure for a small vehicle having a low footrest floor, which improves the lateral rigidity of the vehicle body frame, the rigidity against bending and torsion, and makes it possible to obtain a lightweight frame. .

(Structure of the invention) In order to achieve the above object, the present invention fixes the front ends of a pair of left and right backstays extending rearward to the lower part of one down tube that hangs downward from the head pipe, and A cross member is suspended horizontally between brackets hanging from the footrest floor support part that constitutes the front end of the backstay, and the lower end of the down tube is fixed to the cross member, so that the fixed portion of the down tube and the cross member is fixed to the cross member. , the down tube and the backstay are located below the fixed portion of the backstay, and the fixed portion of the down tube and the cross member is located below the backstay, thereby connecting the down tube and the backstay three-dimensionally. It is characterized by

(Embodiment) A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a side view showing a frame structure according to the present invention, FIG. 2 is a plan view of the main parts thereof, and FIG. 3 is a side view of a tricycle employing the frame structure according to the present invention.

The tricycle 1 consists of a front body 2A and a rear body 2B. The front body 2A includes a front frame 4 having a head pipe 3 at the front end. A front fork 5 is inserted into and supported by the head pipe 3, and the lower end of the front fork 5 is A front wheel 6 serving as a single steering wheel is rotatably supported, and a handle 7 is provided at the upper end of the front wheel 6.

The front frame 4 is composed of a single down tube 8 hanging rearward and downward from the head pipe 3, and a pair of left and right back stays 9, 9 made of pipe material extending rearward from the lower part of the down tube 8. The down tube 8 and the backstays 9, 9 are three-dimensionally connected via one of a plurality of cross members that are horizontally spanned between the backstays 9, 9, as will be described later. The backstays 9, 9 have footrest floor support parts 9a, 9a extending horizontally rearward from the lower part of the down tube 8,
It is formed into a substantially L-shape in side view with seat post parts 9b, 9b rising rearward and upward from the rear of the seat, and includes a down tube 8 including a head pipe 3, a footrest floor support part 9a, 9a, and a seat post part 9b. ，
9b each has a leg shield 1 to cover them.
0, foot rest floor 11, seat post cover 12
is attached, and a seat 13 is provided on the seat post cover 12. In the figure, 14 is a front fender, and 15 is a handle cover.

Rolling joint 1 on the above front body 2A
The rear vehicle body 2B is connected via 6. The rolling joint 16 consists of a joint case 16a that is fixed to the front frame 4 side and a joint shaft 16b that can be rolled freely.At the rear of the rolling shaft 16b, a rear frame 17 on the rear body 2B side is connected from the front end of the joint case 16a. Drooping bracket 18
It is fixed through. A luggage carrier 19 is placed and fixed on the rear frame 17, and at the front end of the rear frame 17 there is a rear fork 2 that supports left and right rear wheels 20, which are drive wheels, in a vertically swingable manner.
The left and right rear wheels 20 are driven by a power unit provided on the rear fork 21, and the rear fork 21 and the rear frame 17
A buffer is installed between the left and right sides. In this way, the front vehicle body 2A is connected to the rear vehicle body 2B for rolling movement. Note that 22 is a cover that also serves as a rear fender.

By the way, the down tube 8 constituting the front frame 4 of the front body 24 of the tricycle 1 described above and the left and right backstays 9 are connected as follows. That is, as shown in FIGS. 1 and 2, the lower part 8a of the down tube 8 is bent rearward, and the front portions of the horizontal footrest floor support portions 9a, 9a of the back stays 9, 9 are spaced apart from side to side. 9c,
9c inward, and the bent portions 9c, 9
The front end portions 9d, 9d of the lower bent portion 8a of the down tube 8 are welded to the left and right sides of the lower bent portion 8a of the down tube 8 at a position forwardly above the rear end portion 8a. Further, brackets 23, 23 are suspended from inside the substantially intermediate portions in the longitudinal direction of the footrest floor support portions 9a, 9a, respectively, and a cross member 24 is horizontally suspended between the front portions of these brackets 23, 23, so that the cross member 24 is 24 is disposed below the footrest floor support portions 9a, 9a, and the rear end portion 8b of the lower bent portion 8a of the down tube 8 is welded to the intermediate portion of the cross member 24.

In the above connection structure, down tube 8
The front ends 9d, 9d of the back stays 9, 9 welded on the left and right sides of the back stays 9, 9 and the footrest floor support parts 9a, 9a of the back stays 9, 9 are connected and welded to the cross member 24 disposed below these. As shown in the figure, it is separated from the rear end portion 8b of the down tube 8 by a distance a in the vertical direction and a distance b in the longitudinal direction,
In other words, down tube 8 and backstay 9,
9 is three-dimensionally connected.

The front end of the case 16a of the rolling joint 16 described above is supported between the rear parts of the brackets 23, 23 hanging from the footrest floor support parts 9a, 9a, and the footrest floor support part 9
The above-mentioned joint case 16 is attached to a bracket 26 provided on a cross member 25 that is suspended horizontally between the lower portions of seat post portions 9b and 9b that are continuous with a and 9a.
The rear part of a is supported, so that the rolling joint 16 is attached to the front frame 4, and the lower end 8b of the down tube 8 is placed behind the cross member 24 to which the lower end 8b of the down tube 8 is welded.

In the embodiment, the frame structure of the present invention was adopted for the front frame of a tricycle with a front and rear body frame divided, but it can of course also be applied to motorcycles, tricycles, etc. in which the front and rear frames are integrated. .

(Effect of the invention) As is clear from the above explanation, according to the invention, the cross member is horizontally suspended between the brackets hanging from the footrest floor support portions forming the front ends of the left and right back stays, and the cross member is placed between the footrests. The lower end of the down tube is fixed to this cross member, and the front ends of the left and right backstays are fixed to a position above and in front of the lower end of the down tube. The fixed part of the cross member is located below the fixed part of the down tube and backstay, and the fixed part of the down tube and cross member is located below the back stay, so that the down tube and the pair of left and right back stays are tertiary. Since the body frame is originally connected, the strength of these connections can be improved compared to the conventional planar connection structure, so the body frame including the gussets can be made smaller, and the body frame It is possible to reduce the weight of the vehicle body frame while ensuring sufficient rigidity in the lateral direction and rigidity against bending and torsion.

In addition, in a tricycle having a joint approximately in the center of the vehicle body as in the embodiment, the joint can be commonly attached to the bracket of the cross member, so the number of parts can be reduced and the number of parts can be reduced. Since the joint can be placed behind the cross member, the cross member can play the role of a guard and protect the joint.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a frame structure according to the present invention, FIG. 2 is a plan view of the main parts thereof, and FIG. 3 is a side view of a tricycle employing the frame structure according to the present invention. In the figure, 1 is a tricycle, 3 is a head pipe,
8 is a down tube, 9 is a backstay, 23 is a bracket, 24 is a cross member, and a and b are distances.

Claims (1)

[Scope of utility model registration request] The front ends of a pair of left and right backstays extending rearward are fixed to the lower part of a single down tube that hangs backward and downward from the head pipe, and the brackets hanging from the footrest floor support part that constitute the front ends of the left and right backstays are fixed. A cross member is horizontally suspended between them, the lower end of the down tube is fixed to the cross member, and the fixed portion of the down tube and the cross member is located below the fixed portion of the down tube and the backstay. , and a fixed portion of the down tube and the cross member is located below the backstay. A frame structure for a small vehicle having a low footrest floor.