JP4902841B2 - Body frame - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle body frame capable of thinning thickness of a cross pipe and mounting required parts to the cross pipe at high accuracy. <P>SOLUTION: A bracket 27 for mounting parts is integrally formed on a cross pipe 34 provided at a bottom of a main frame 1 and extending rightward and leftward. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a body frame that forms a skeleton of a vehicle such as a motorcycle.

A body frame of a motorcycle is generally provided with a pair of left and right swing arm brackets at the rear end of a main frame, and a swing arm that supports the rear wheel is vertically moved via a pivot shaft at the front end of the swing arm bracket. A center stand for supporting the vehicle body upright is attached while being supported in a swingable manner. The center stand is rotatably supported by a support member provided on the bracket, with the bracket fixed to a cross pipe that is attached to the pair of left and right swing arm brackets (see Patent Document 1). ). In the single shock type, a shock absorber link mechanism for absorbing an impact from the rear wheel is connected to the swing arm bracket.
JP-A-11-165668

  However, in the conventional center stand mounting structure, since the bracket is fixed to the cross pipe by welding, thermal strain is generated during the welding, and stress concentration is likely to occur at the welded portion of the cross pipe and the bracket. Therefore, it is necessary to use a thick pipe material having a thickness of, for example, 5 to 6 mm as the cross pipe, which contributes to an increase in the weight of the vehicle body frame. In addition, a support member serving as a fulcrum of the link mechanism of the shock absorber is fixed to the cross pipe by welding. However, the support member is likely to be deformed due to thermal strain generated during the welding, and the mounting accuracy of the link mechanism is reduced. .

  Therefore, an object of the present invention is to provide a vehicle body frame in which a required part can be accurately attached to the cross pipe while reducing the thickness of the cross pipe.

In order to achieve the above object, a vehicle body frame according to the present invention is provided with a bracket for mounting a component on a cross pipe provided at a lower portion of a main frame and extending left and right, and the bracket projects from the cross pipe. A pair of left and right first mounting portions to which a link member connected to the shock absorber is mounted; and a pair of left and right second mounting portions to which a stand is mounted extending from the pair of left and right first mounting portions. 1 mounting part projects downward from the cross pipe, the second mounting part extends downward from the first mounting part, the stand has a pair of left and right main legs attached to the second mounting part, the link member is disposed between the pair of left and right main legs, said re-entrant recess is formed in left and right inward first mounting portion, between the inner wall facing each of the two recesses, Bo It said link member with the door is attached.

According to this configuration, the first attachment portion and the second attachment portion can be combined and formed in a small space, and the periphery of the cross pipe becomes compact.

In the present invention, preferably, the bracket and the cross pipe are integrally formed by molding. According to this configuration, since the bracket for mounting the component is integrally formed on the cross pipe, thermal strain and stress concentration on the welded portion when a separate bracket is fixed to the cross pipe by welding as in the past. Since this does not occur, the required parts can be accurately attached to the bracket while reducing the thickness of the cross pipe and reducing the weight. The bracket is integrally provided by, for example, casting such as casting or forging. In this way, the cross pipe with the bracket integrally formed can have a shape having a large fillet at the corner that becomes the boundary between the cross pipe and the bracket, thereby avoiding stress concentration. The thickness of the cross pipe can be further reduced.

  According to the vehicle body frame of the present invention, the bracket for mounting the components is integrally formed on the cross pipe provided at the lower part of the main frame, so that welding is not required, so that thermal strain during welding and stress concentration at the welding location Therefore, the required parts can be accurately attached to the bracket while reducing the thickness of the cross pipe and reducing the weight. Furthermore, the cross pipe can be further thinned by forming the corner portion that becomes the boundary between the cross pipe and the bracket into a shape having a large radius and suppressing the stress concentration.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a side view showing a motorcycle including a body frame according to an embodiment of the present invention. In the motorcycle shown in the figure, a head pipe 2 is attached to a front end portion of a main frame 1 constituting a front half portion of a vehicle body frame FR, and a steering shaft (not shown) is rotatably inserted into the head pipe 2. The upper bracket 4 and the lower bracket 5 are supported via the front bracket 8, the front fork 8 is supported on the upper bracket 4 and the lower bracket 5, and the front wheel 9 is supported on the lower end portion of the front fork 8. A handle 10 is attached to the upper bracket 4 at the upper end of the front fork 8.

  The main frame 1 has a side surface shape that slightly rises from the front part to the middle part in the front-rear direction and curves downward from the middle part toward the rear part. A pair of left and right swing arm brackets 11 are provided at the lower rear end of the main frame 1. A swing arm 12 is supported on the swing arm bracket 11 via a pivot shaft 13 at the front end so as to be swingable up and down. Yes. A rear wheel 14 is supported at the rear end of the swing arm 12. A multi-cylinder engine E is supported at the lower center of the main frame 1. Further, a plurality of exhaust pipes 18 are connected to the cylinder head 17 of the engine E, and these exhaust pipes 18 are connected to mufflers 20 arranged one by one on the left and right sides of the rear part of the vehicle body.

  A rear frame (seat rail) 21 connected to the rear portion of the main frame 1 constitutes the rear half of the frame FR, and a single seat in which a rider and a passenger are connected to the rear frame 21. 22 is supported. A fuel tank 19 is attached between the handle 10 and the seat 22 at the upper part of the main frame 1, that is, the upper part of the vehicle body. A resin cowling 25 that covers a portion from the front of the handle 10 to the side of the front portion of the vehicle body is attached to the front portion of the vehicle body.

  FIG. 2 shows a rear view of the main frame 1, in which the rear frame 21 (FIG. 1) connected to the main frame 1 is not shown. The main frame 1 has a monocoque structure (a clamshell structure or a stress skin structure), and an air cleaner portion 26 in which a cleaner element (not shown) is accommodated is provided in an internal space. A pair of left and right access holes 28 are opened in the upper surface of the intermediate portion of the main frame 1, and the access holes 28 are mounted on the upper surface of the main frame 1 and attached to the fuel tank 19 (FIG. 1). It is blocked by. A pair of left and right swing arm brackets 11, 11 are integrally formed at the rear end portion of the main frame 1, and welding P is performed with the upper cross pipe 33 being bridged between the upper end portions of both the swing arm brackets 11, 11. The lower cross pipe 34 is bridged between the lower ends of the swing arm brackets 11 and 11 by welding P. A boss portion 37 of FIG. 2 that supports the pivot shaft 13 of the swing arm 12 of FIG. 1 is formed at the middle portion of the swing arm brackets 11 and 11 in the vertical direction.

  As shown in FIG. 3, the bracket 27 formed integrally with the lower cross pipe 34 protrudes below the swing arm bracket 11. An upper end portion of a center stand 32 for standing and holding the vehicle body is rotatably connected to the bracket 27. The rear wheel suspension device of the motorcycle is a so-called single shock type, and a link mechanism LM is connected to the lower part of a single shock absorber 30, and one end of one link member 29 of the link mechanism LM is The bracket 27 is swingably connected via a bolt 50 (to be described later) serving as a support shaft. The other end of the link member 29 is connected to the lower end of the shock absorber 30. Further, the intermediate part of the link member 29 is connected to the swing arm 12 via a pair of left and right connecting links 31. Details of these configurations will be described later.

  The lower cross pipe 34 shown in FIG. 2 and the bracket 27 for mounting components are integrally formed by die molding by casting a metal such as an aluminum alloy, for example. The bracket 27 has a pair of left and right first mounting portions 38 and 38 and a pair of left and right second mounting portions 39 provided extending downward from the first mounting portions 38 and 38. Between the pair of first mounting portions 38, 38, a link member 29, which is a first component, is rotatably mounted. The second attachment portions 39, 39 each have a pair of attachment pieces 39a, 39a, and the upper end portion of the center stand 32, which is the second component, is rotatably attached to these attachment pieces 39a, 39a. .

  FIG. 4 is a cross-sectional view of the lower cross pipe 34 and the bracket 27. A relatively large fillet is attached to a corner 41 of the pair of left and right first mounting portions 38, 38 formed on the bracket 27 and the lower cross pipe 34. Each first attachment portion 38 is formed with a recess 45 that is recessed inwardly (in the center of the vehicle body), and a bolt for attaching the link member 29 to the opposite inner walls 46 of both recesses 45, 45. Insertion holes 47 and 47 are formed, respectively. When the link member 29 is mounted between the first mounting portions 38, 38, the bolt 52 is fitted from one (left side) bolt insertion hole 47 to the mounting hole 29 a at one end of the link member 29 and the other. By inserting the nut 53 inserted into the other recess 45 through the bolt insertion hole 47 on the (right side), one end of the link member 29 is rotatably mounted between the first mounting portions 38 and 38. . Thereby, the short thing of the grade which penetrates the inner walls 46 and 46 which both the 1st attachment parts 38 oppose can be used as the volt | bolt 50, and weight reduction can be achieved.

  One end of a pair of left and right connecting links 31 is rotatably connected to an intermediate portion of the link member 29 by a bolt 57 and a nut 58 inserted into a bush 56 fitted in the mounting hole 29b of the intermediate portion. ing. At the other end of the link member 29, the attachment piece 30a at the lower end of the shock absorber 30 is rotatable by a bolt 61 and a nut 62 inserted through a bush 60 fitted in the attachment hole 29c at the other end. It is connected. As shown in FIG. 3, the other ends of the pair of left and right connecting links 31 are rotatably connected to an attachment piece (bracket) 63 of the swing arm 12 by bolts 64 and nuts 65. The upper end portion of the shock absorber 30 is supported by an attachment piece 67 attached to the upper cross pipe 33. Therefore, the link member 29 receives the operation of the swing arm 12 that swings about the pivot shaft 13 as a fulcrum through the connection link 31, and this operation is buffered by the buffer device 30.

The center stand 32 shown in FIG. 2 includes a pair of left and right main legs 71, 71, support members 72, 72 provided at the upper ends of the main legs 71, a connecting rod 73 that connects the main legs 71, 71, A foot stay 74 provided on one (left side in FIG. 2) main leg 71 and a spring locking pin 75 provided on the other (right side in FIG. 2) main leg 71 are provided. As shown in FIG. 4, the center stand 32 has bushes 77 inserted into the through holes of the left and right support members 72, 72, and each support member 72 is between a pair of mounting pieces 39 a, 39 a of the second mounting portion 39. The main legs 71 and 71 are pivotally supported by both the second mounting portions 39 and 39 with the bolt 78 as a fulcrum. A mounting plate 80 is applied to the boss portion 86 bulging outward from the outer wall of the first mounting portion 38 , and the fixing screw 88 is screwed into the screw hole 89 of the boss portion 86, so that the boss portion 86 is fixed.

  Both ends of the tension spring 82 are hooked on a spring locking pin 75 provided on the main leg 71 shown in FIG. 2 and a support pin 81 planted on the mounting plate 80. As a result, the center stand 32 receives the spring force of the tension spring 82 and is selectively held at the standing position indicated by the solid line and the retracted position (not shown) that is flipped up backward.

  Further, as shown in FIG. 4, ribs 85, 85 that extend upward from the outer walls of the first mounting portions 38, 38, that is, the hollow portions of the cross pipe 34, are integrally formed on the lower cross pipe 34. The rigidity of the lower cross pipe 34 is enhanced by the ribs 85, 85.

  FIG. 5 is a perspective view of the state in which the center stand 32, the link member 29, and the pair of connecting links 31 are attached to the bracket 27 integral with the lower cross pipe 34, as viewed from the rear. As shown in the figure, the rib 85 extends in the front-rear direction along the inner bottom surface of the hollow cross pipe 34. The mounting plate 80 has a substantially inverted triangular shape in a side view, and the support pins 81 are implanted in the lower part. Two fixing screws 88 are provided through the upper portion of the mounting plate 80.

  In the above configuration, the bracket 27 for component mounting is integrally formed with the lower cross pipe 34. Therefore, when a separate bracket is fixed to the cross pipe by welding as in the prior art, generation of thermal strain during welding or welding is performed. Since the stress concentration on the part does not occur, it is possible to attach the parts such as the link member 29 and the center stand 32 to the bracket 27 with high accuracy while reducing the thickness of the lower cross pipe 34 and reducing the deformation.

  Further, since the lower cross pipe 34 and the bracket 27 are integrally formed by casting or the like, as shown in FIG. 4, the corner 41 of the cross pipe 34 and the bracket 27 has a shape having a large radius. can do. As a result, stress concentration can be avoided, and the lower cross pipe 34 can be made thinner. A large impact force is applied to the lower cross pipe 34 from the shock absorber 30 of FIG. 3 through the link member 29, and the weight of the vehicle body is applied from the center stand 32. Therefore, conventionally, the lower cross pipe 34 shown in FIG. The wall thickness t of the pipe 34 is set to 5 to 6 mm, but in the present invention, it can be reduced to about 3 mm.

  The bracket 27 is provided with second attachment portions 39, 39 to which a center stand 32, which is a second component, is attached to a pair of left and right first attachment portions 38, 38 to which a link member 29, which is a first component, is attached. Since it is a structure, the first attachment portions 38 and 38 and the second attachment portions 39 and 39 can be formed in combination in a small space, and the periphery of the cross pipe 34 can be made compact.

  Note that the bracket 27 may be provided with a second attachment portion for attaching the side stand instead of the center stand 32. Moreover, although the case where this invention was applied to the motorcycle was illustrated in the said embodiment, this invention is applicable also to a three-wheeled vehicle and a four-wheeled vehicle for rough terrain other than a motorcycle.

1 is a side view showing a motorcycle including a body frame according to an embodiment of the present invention. It is a rear view which shows the main frame in a vehicle body frame same as the above. It is a left view which shows the principal part in a vehicle body frame same as the above. It is sectional drawing which shows the principal part in a vehicle body frame same as the above. It is the perspective view seen from the back which shows the principal part in a vehicle body frame same as the above. It is a perspective view.

Explanation of symbols

FR body frame 1 main frame 27 bracket 29 link member (first part)
30 shock absorber 32 center stand (second part)
34 Lower cross pipe (cross pipe)
38 1st mounting part 39 2nd mounting part

Claims (3)

A bracket for component mounting is provided on the cross pipe that is provided at the lower part of the main frame and extends to the left and right.
The bracket includes a pair of left and right first mounting portions to which a link member that protrudes from the cross pipe and is coupled to a shock absorber is mounted, and a pair of left and right first mounting portions that extend from the pair of left and right first mounting portions and to which a stand is mounted. 2 mounting parts,
The first attachment portion protrudes downward from the cross pipe, the second attachment portion extends downward from the first attachment portion,
The stand has a pair of left and right main legs attached to the second attachment portion,
The link member is disposed between the pair of left and right main legs;
A vehicle body frame in which recesses recessed inwardly are formed in the pair of left and right first mounting portions, and the link member is mounted using bolts between opposing inner walls of the two recesses.   2. The vehicle body frame according to claim 1, wherein the pair of left and right second attachment portions has a pair of attachment pieces, and the main legs of the stand are rotatably attached to the pair of attachment pieces.   The vehicle body frame according to claim 1 or 2, wherein the bracket and the cross pipe are integrally formed by molding.

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