JPH0741862B2 - Frame for motorcycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a frame for a motorcycle.

[Conventional technology]

Conventionally, in road sports motorcycles, a down tube and an engine mount portion in the center of the frame are interrupted, and a diamond frame in which an engine is mounted in this portion and a crankcase is a part of the frame is used. Then, as it is called a wide frame, a square pipe is used for the main frame, and it is proposed to extend it from the steering head pipe to the left and right of the vehicle body and to extend it rearward and downward to improve the appearance and rigidity of the vehicle body. There is.

[Problems to be solved by the invention]

By the way, the recent increase in output of the engine requires higher rigidity of this frame. To meet this demand, it is conceivable to make the square pipe of the main frame vertically long.

However, in the above diamond frame, when a vertically long pipe is used, it is difficult to bend it in the vertical plane, and the rear end of the main frame is bent into an arc like the conventional one, and the rear wheel is supported inside this bend. It is not possible to adopt a structure in which the placket that pivotally supports the swing arm is fixed by welding.

As another structure, the main frame extends linearly downward and rearward from the steering head pipe, and the engine support and swing arm pivot support brackets are abutted and fixed so as to match the shape of the rear end. It is conceivable to connect a seat pillar supporting the seat rail to the. However, in this case, the bracket has a complicated shape, and high precision is required for the abutting portion, which has been a factor of increasing the manufacturing cost of the entire frame. That is, the bracket has a complicated shape by forming a simulated rail-shaped portion in order to have continuity with the main frame, and the molding of the bracket becomes extremely complicated, and the seat pillar is attached to the bracket. There is a problem in that the brackets must be connected so as not to be displaced with respect to each other, and thus the mounting accuracy of the bracket must be increased.

The present invention has been made to solve this, and an object of the present invention is to improve the rigidity of the frame and to obtain a frame that is easy to manufacture and does not increase the cost.

[Means for solving problems]

The present invention has been made in consideration of the above-mentioned conventional drawbacks, and includes a main frame composed of a pair of right and left square pipes extending laterally from the steering head pipe and curved along the side edges of the tank and then extending rearward and downward. , A front end is connected to an upper surface of an intermediate portion of each of the main frames, extends inward from the front end, bends, and extends in a straight line slightly upward toward the rear, from a square pipe supporting a seat. A pair of left and right seat rails, the front end of which is connected to the upper surface of the rearmost portion of each of the main frames, and the rear end side of which is fixed in the middle of the seat rail and near the connecting member that connects the left and right seat rails. With a pair of left and right seat pillars consisting of square pipes that support the seat rail,
The front and rear edges of the bracket that pivotally supports the swing arm that supports the rear wheels are bent toward the inside of the vehicle body to form a groove-shaped cross section, and the upper edge of the bracket extends from the rear end of the main frame to the front edge of the seat rail. Fix it on the side surface of the nearby main frame in a substantially horizontal straight line, and fix the upper part of the front edge of the bracket to the lower surface of the main frame, and apply the upper part of the rear edge of the bracket to the rear end of the main frame to attach it to the main frame. A frame for a motorcycle is provided in which the bracket is fixed and is formed so as to be concave toward the rear, and the above-mentioned conventional drawbacks are eliminated.

[Work]

In the present invention, the frame is composed of a main frame made of a square pipe, a seat rail, a seat pillar, and a bracket, and the bracket is not connected to the seat pillar, and the upper edge shape of the bracket is easily formed. By doing so, the frame constituent members can be easily connected to each other, and the manufacturing cost of the frame can be reduced.

〔Example〕

Next, the present invention will be described in detail based on an embodiment shown in FIGS. 1 and 2.

In the figure, reference numeral 1 denotes a motorcycle frame, which is divided into left and right from a steering head pipe 2 and is curved so as to be along a side edge of a tank a, and extends rearward and downward. Frames 3, 3 and a down tube 4 that is connected to the lower part of the steering head pipe 2 and supports the front part of the engine c via a stay b.
And a pair of left and right seat rails 5 and 5 and seat pillars 6 and 6 connected to the main frames to support the seat d, and a pair of left and right steel plate brackets 7 connected to the main frames to support the rear part of the engine c. , 7
It is equipped with and. The frame 1 is a diamond frame in which the down tube 4 supports the front part of the engine c and the steel plate bracket 7 supports the rear part of the engine c, and the mountability of the engine is extremely good. Further, as shown in FIG. 1, the steel plate bracket 7 is welded and fixed to the rear end of the main frame 3 and pivotally supports the swing arm e. The welded and fixed portion of the steel plate bracket 7 will be described in detail. As shown in FIG. 2, the bracket upper edge 7a extends from the rear end 30c of the main frame 3 to the side surface of the main frame 3 near the front edge of the seat rail 5. The bracket front edge 7b and the bracket rear edge 7c are bent toward the inside of the vehicle body to form the horizontal cross section of the steel plate bracket 7 into a groove shape (substantially [shape]). There is. And
The upper part of the front edge 7b of the bracket is the lower surface 30b of the main frame 3.
The upper end of the bracket rear edge 7c is applied to the opening of the rear end 30c of the main frame 3 and fixed to the main frame by welding. Further, in this steel plate bracket 7, its front edge 7b is formed so as to be concave toward the rear, so that the workability of mounting the engine is improved.

The seat rails 5 and 5 and the seat pillars 6 and 6 are formed of square pipes, and the front ends of the seat rails are welded and fixed to the upper surface 30a of the rear portion of each main frame, and are bent inward and then directed rearward. The seat d so as to extend linearly and cover the seat rail.
The left and right seat rails are connected by the connecting member 50 to which the lamps are attached and the connecting member 51 to which the lamps at the rear of the vehicle body are attached, and the connecting member 50 and the seat biller are connected as shown in the figure.
The rear ends of 6, 6 are close to each other.

The front ends of the seat pillars are welded and fixed to the upper surfaces of the rearmost portions of the main frames, bent inward and then extended to the seat rail side, and joined to the seat rails at the rear end linear portions 60, respectively. The seat rail to which the seat d is attached is interposed and supported between the seat rail and the main frame. Thus, the seat rails 5 and 5 and the seat pillars 6 and 6 are made of steel plate brackets.
There is no need to intervene with 7, 7 intervening, and each connecting work directly to the main frame, that is, frame assembling work becomes easy, and the manufacturing cost can be reduced.

Further, as shown in FIG. 1, the main frames 3, 3 and the seat rails 5, 5 are straight in a side view, and in the shape before connection (welding), they are bent in a plane perpendicular to one side of the square pipe. ing. Therefore, the bending processing of the main frames 3, 3 and the seat rails 5, 5 is common to the left and right members, and the manufacturing cost can be reduced also in this respect.

〔The invention's effect〕

As described above, according to the present invention, the main frame is linearly extended downward from the steering head pipe, and the bracket is provided with the upper edge of the main frame located in the vicinity of the front end of the seat rail from the rear end of the main frame. Fixed in a substantially horizontal straight line on the side of the bracket, the front edge of the bracket and the rear edge of the bracket are bent toward the inside of the car body to form a groove-shaped cross section, and the upper front edge is on the lower surface of the main frame and the upper rear edge is Since it is fixed to the main frame by applying it to the rear end of the main frame, it is not necessary to bend the rear end of the main frame into a vertical plane, and a vertically long square pipe can be used. Is grooved and is strongly reinforced by the bracket extending in the vicinity of the front end of the seat rail, so that the rigidity of the entire frame can be increased. In addition, the bracket does not require high precision as in the case of butt-welding and fixing in conformity with the shape of the end portion of the main frame, and since it has a simple groove shape, it is easy to manufacture and it is possible to prevent cost increase. Like Also, since the upper part of the rear edge of the bracket is applied to the rear end of the main frame, it protects the rear end processing part of the main frame, prevents mud etc. from entering when the rear end is open, and also has a dedicated lid. Since no member is required, the cost can be reduced also from this point. Even if the upper edge of the bracket extends to the vicinity of the front end of the seat rail, the front edge of the bracket is formed so as to be recessed rearward, so that the engine can be mounted below the main frame from the side of the vehicle body. It will not interfere with the mounting work. Further, the bracket has a groove-shaped cross section, and the distance between the shaft supports of the swing arm can be made large in the vehicle body width direction, so that the swing arm can be stably supported.

Further, since the front end of the seat pillar is fixed to the upper surface of the main frame, the front end of the seat pillar is welded and fixed to the straight portion of the main frame, which facilitates the work, and the arc-shaped portion of the conventional frame. There is no need to change its arcuate curvature, unlike the one that fixes the bracket to. In addition, like the conventional frame in which the front end of the seat pillar is fixed to the placket and the bracket is fixed to the main frame, the accuracy of the frame can be improved without stacking members with dimensional errors. It has an excellent effect on sex.

[Brief description of drawings]

FIG. 1 is a side view of a vehicle incorporating an embodiment of a motorcycle frame according to the present invention, and FIG. 2 is an explanatory view of the embodiment. 1 …… Frame 3 …… Main frame 5 …… Seat rail 6 …… Seat pillar 7 …… Steel plate bracket

Claims (1)

[Claims] 1. A main frame composed of a pair of left and right square pipes extending laterally from a steering head pipe and curved along side edges of a tank and extending rearward and downward, and a front end on an upper surface of an intermediate portion of each main frame. A pair of left and right seat rails formed of square pipes for supporting the seat, the main rails being connected to each other, extending inward from the front end, bending, and extending rearward in a slightly upward linear shape. A left and right pair consisting of square pipes, each of which has a front end connected to the upper surface of the rearmost part thereof and a rear end side which is an intermediate part of the seat rail and fixed near a connecting member connecting the left and right seat rails to support the seat rail. The front and rear edges of the bracket that pivotally supports the swing arm that supports the rear wheels are bent inward of the vehicle body to form a groove-shaped cross section. From the rear edge of the main frame, fix the upper edge of the bracket on the side of the main frame near the front edge of the seat rail in a substantially horizontal straight line, and fix the upper front edge of the bracket to the lower surface of the main frame. A frame for a motorcycle characterized in that the upper portion of the rear edge is fixed to the main frame by applying the upper portion of the rear edge to the rear end of the main frame, and the bracket is formed to be concave toward the rear.