JP4870198B2 - Motorcycle frame - Google Patents

Description

  The present invention relates to a motorcycle frame, and more particularly to a motorcycle frame in which a bracket for mounting a component is disposed on a lower frame extending downward from a head pipe.

  For example, a motorcycle frame mainly includes a head pipe for pivotally supporting a steering shaft on which a steering handle is mounted, a main frame extending rearward from the head pipe, and extending downward from the head pipe. With a down tube. The motorcycle frame includes a lower frame extending substantially rearward from the lower end of the down tube, and a pivot frame (also referred to as a swing arm bracket) between the rear end of the lower frame and the rear end of the main frame. There are also those connected by (see, for example, Patent Documents 1 and 2).

JP 2004-331001 A JP 2004-330999 A

  By the way, various components are attached to the frame constituted by the main frame, the pivot frame, the down tube, and the lower frame. For example, there is an engine as the main one, and this engine is supported on the frame via a plurality of brackets. When the engine is water-cooled, a radiator is disposed in front of the down tube, and the radiator is supported by the down tube via a bracket. In particular, in a motocrosser type motorcycle, an engine guard is disposed below the engine, and the engine guard is supported by the lower frame via a bracket. Further, in order to further strengthen the connection of the main frame and the down tube to the head pipe, the main frame and the down tube may be connected with a reinforcing gusset.

  Thus, conventionally, various brackets and gussets are formed separately from each other and welded to the frame. However, in this case, it is necessary to weld each bracket etc. while ensuring the accuracy of assembling each component (engine, radiator, gusset, etc.) to the frame. It is difficult to plan.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a motorcycle frame capable of reducing the number of welded parts and realizing improved work efficiency.

  The present invention has been made in view of the above-described circumstances, and a motorcycle frame according to the present invention includes a head pipe that supports a steering shaft, and an engine mounted on the head pipe that extends downward from the vehicle body. A lower frame, a bracket that attaches a component to the lower frame, and a connection member that is attached to the lower frame and connects another component to the lower frame, the bracket being attached to the connection member It is integrally formed.

  With such a configuration, it is possible to reduce the number of independent welding parts, and it is possible to improve the work efficiency while ensuring the accuracy with which the components are assembled to the frame.

  The main body further includes a main frame extending from the head pipe to the rear of the vehicle body, the connecting member includes a gusset for connecting the main frame and an upper portion of the lower frame, and the bracket is attached to the lower frame. A radiator mounting bracket for attaching a radiator may be provided, and the gusset and the radiator mounting bracket may be integrally formed. With such a configuration, the gusset and the radiator mounting bracket can be integrated, and there is no need to weld them separately.

  Also,. The lower frame has a down tube extending downward from the head pipe, and a lower frame extending from the lower portion of the down tube to the rear of the vehicle body, and the gusset is provided on an upper rear side of the down tube. A main body connecting the main frame and the down tube; and an extending portion extending from the main body toward the front of the vehicle body to the side of the down tube, and the radiator mounting bracket is integrated with the extending portion. It may be formed automatically. With such a configuration, it is not necessary to separately provide the gusset and the radiator mounting bracket, and the number of parts can be reduced.

  The bracket includes an engine mounting bracket for mounting the engine on the lower frame, and the connecting member includes a guard mounting for connecting the lower frame and an engine guard covering a lower portion of the engine, The engine mounting bracket and the guard mounting tool may be integrally formed. By adopting such a configuration, the engine mounting bracket and the guard mounting tool can be integrated, and there is no need to weld them separately.

  The lower frame includes a down tube extending downward from the head pipe and a pair of left and right lower frames extending from the lower portion of the down tube to the rear of the vehicle body, and the engine mounting bracket includes the left and right lower frames. A main body part that is attached to the upper side of the middle part and attaches the engine to the lower frame; and a projecting part that protrudes from the main body part toward the center in the left-right direction of the vehicle body. You may form integrally in the protrusion part of the said engine mounting bracket. With such a configuration, the engine mounting bracket and the guard mounting tool can be integrated with a simple configuration.

  According to the motorcycle frame of the present invention, it is possible to reduce the number of welded parts to improve work efficiency and to improve the accuracy of assembly of components to the frame.

1 is a side view of a motocrosser type motorcycle employing a frame according to an embodiment of the present invention. Fig. 2 is a side view of a frame provided in the motorcycle shown in Fig. 1. It is a side view which shows the structure of the gusset shown in FIG. It is the rear view which looked at the gusset shown in FIG. 3 from IV arrow direction. FIG. 3 is a perspective view showing left and right engine mounting brackets attached to the lower frame shown in FIG. 2 and the surrounding configuration. FIG. 6 is a side view of the right engine mounting bracket shown in FIG. 5. It is the front view which looked at the engine mounting bracket shown in FIG. 6 from the VII arrow direction.

  Hereinafter, a motorcycle frame according to an embodiment of the present invention will be specifically described with reference to the drawings. FIG. 1 is a side view of a motorcycle 1 of a motocrosser type, and FIG. 2 is a side view of a frame 2 provided in the motorcycle 1 shown in FIG. In FIG. 1, the frame 2 is indicated by a solid line, and the other portions are indicated by two-dot chain lines. In addition, the concept of direction used in the following description will be described as being the same as the concept of direction viewed from a rider (not shown) riding on the motorcycle 1.

  As shown in FIG. 1, the motorcycle 1 includes a front fork 3 having a predetermined caster angle and extending in a substantially vertical direction, and a front wheel 4 as a steering wheel is rotatably provided at a lower portion of the front fork 3. It is supported. A lower part of a steering shaft 6 extending in the vertical direction is connected to the upper part of the front fork 3, and a bar-type steering handle 7 extending in the horizontal direction is supported on the upper part of the steering shaft 6 at a central portion. Yes. The steering shaft 6 is pivotally supported by a head pipe 10 constituting the frame 2 so that the rider can turn the front wheel 4 left and right by turning the steering handle 7 left and right. Yes.

  As shown in FIGS. 1 and 2, the frame 2 includes a head pipe 10 and a main frame 11 extending rearward while facing slightly downward from the upper portion of the head pipe 10, and the main frame 11 includes a pair of left and right main frames 11. 1 and 2 (only the left main frame 111 is shown in FIGS. 1 and 2; see FIG. 4 for the right main frame 112). Further, an upper part of a down tube (lower frame) 12 extending downward while being slightly rearward facing from the lower part of the head pipe 10 is connected, and a lower frame (lower frame) 13 is extended from the lower part of the down tube 12. Yes. The lower frame 13 is also composed of a pair of left and right lower frames 131 and 132 (only the left lower frame 131 is shown in FIGS. 1 and 2; see FIG. 5 for the right lower frame 132). The frame 13 extends substantially downward from the lower part of the down tube 12, is curved in the middle, and extends rearward. A pivot frame (also referred to as a swing arm bracket) 14 is connected between the rear portion of the lower frame 13 and the rear portion of the main frame 11.

  As shown in FIG. 2, a main frame tongue 10 </ b> A extends substantially rearward from the upper portion of the head pipe 10, and covers the front portion of the main frame 11 from above. Further, from the lower part of the head pipe 10, a tongue piece 10 </ b> B for a down tube extends substantially downward, and covers the upper part of the down tube 12 from the front.

  As shown in FIG. 2, a pivot hole 14A is formed at a position slightly lower than the center position in the vertical direction of the pivot frame 14, and the front portion of the swing arm 16 extending substantially in the front-rear direction is inserted into the pivot hole 14A. It is supported by a pivot shaft 14B. As shown in FIG. 1, a rear wheel 5 as a driving wheel is rotatably supported at the rear part of the swing arm 16, and the rear wheel 5 is swingable in the vertical direction about a pivot shaft 14B. It has become. A suspension unit 17 is interposed between the upper portion of the pivot frame 14 and the swing arm 16 to urge the swing arm 16 downward.

  As shown in FIGS. 1 and 2, a gusset 30 and a support bar 31 for reinforcing the rigidity of the frame 2 are provided between the front portion of the main frame 11 and the upper portion of the down tube 12. As will be described later, the gusset 30 integrally includes a radiator mounting bracket 32 (see FIG. 2), and the radiator mounting bracket 32 supports a radiator 18 disposed in front of the down tube 12.

  An engine E is mounted in a space S surrounded by the head pipe 10, the main frame 11, the down tube 12, the lower frame 13, and the pivot frame 14 constituting the frame 2. This engine E is a four-cycle engine in the present embodiment, and is supported via another bracket 51 with respect to a plurality of engine mounting brackets 50a, 50b, 50c (see FIG. 2) provided in each part of the frame 2. Has been. As shown in FIG. 1, the output shaft (not shown) of the engine E is connected to the rear wheel 5 via a chain (or belt) C, and when the engine E is driven, the rear wheel 5 rotates in conjunction, The motorcycle 1 obtains a driving force.

  As shown in FIG. 1, a fuel tank 19 is provided above the main frame 11 and behind the steering shaft 6, and a seat 20 straddling a rider is disposed behind the fuel tank 19. ing.

  FIG. 3 is a side view showing the configuration of the gusset 30, and FIG. 4 is a rear view of the gusset 30 shown in FIG. 3 and 4, the main frame 11 (111, 112) and the down tube 12 are indicated by a two-dot chain line.

  As shown in FIG. 3, the gusset 30 extends from the main body portion 35 connecting the main frame 11 and the down tube 12 toward the front side (a direction orthogonal to the extending direction of the main body portion 35). And provided extension portions (forward extension portions) 36 and 36. The main body portion 35 has a down tube connecting portion 37 extending substantially vertically along the longitudinal direction of the down tube 12, and the down tube connecting portion 37 covers the rear surface of the down tube 12. . The down tube connecting portion 37 has a channel shape in which a cross section perpendicular to the longitudinal direction is opened forward, and the width direction dimension is substantially the same as the width direction dimension of the upper portion of the down tube 12. The gusset 30 is connected to the down tube 12 by welding a portion 30 </ b> A along the front edge of the left and right side wall portions 37 </ b> B of the down tube connecting portion 37.

  The main body portion 35 also has a main frame connection portion 38 provided on the upper side of the down tube connection portion 37 and connected to the main frame 11. The main frame connecting portion 38 includes an inner connecting portion 38A extending in a claw shape from the upper portion of the rear wall portion 37A (see also FIG. 4) of the down tube connecting portion 37 and the left and right sides of the down tube connecting portion 37. It has a triangular lower side connection part 38B extending in a pointed shape from the upper part of the side wall part 37B. As shown in FIG. 4, the inner connection portion 38 </ b> A is formed to have a slightly larger dimension in the width direction than the down tube connection portion 37.

  As shown in FIGS. 3 and 4, the main frame connecting portion 38 is connected to the front portions of the left and right main frames 111, 112 that are opened rearward. More specifically, the left main frame 111 extends obliquely leftward from the front of the gusset 30. The front portion of the main frame 111 has an outer wall portion on the center side in the width direction supported by the inner connection portion 38A of the main frame connection portion 38, and the lower outer wall portion thereof is supported by the main frame connection portion 38. Is supported by the lower connection portion 38B. In this state, the portion 30B along the peripheral edge of the main frame connecting portion 38 is welded, and the gusset 30 and the left main frame 111 are connected.

  The right main frame 112 is similarly connected to the gusset 30. That is, the right main frame 112 is extended obliquely from the front of the gusset 30 to the right rearward. The front portion of the main frame 112 has an outer wall portion on the center side in the width direction supported by an inner connection portion 38A of the main frame connection portion 38, and a lower outer wall portion of the main frame connection portion 38 of the main frame connection portion 38. It is supported by the lower connection portion 38B. In this state, the portion 30C (see FIG. 4) along the peripheral edge of the main frame connection portion 38 is welded, and the gusset 30 and the right main frame 112 are connected.

  In the down tube connecting portion 37 of the gusset 30, a bar attaching portion 40 for attaching the support bar 31 is provided at a position slightly lower than the center in the longitudinal direction. This bar attaching part 40 is extended in the left-right direction at the rear part of the down tube connecting part 37, and has a channel shape that opens in a cross section orthogonal to the longitudinal direction toward the rear. A substantially U-shaped support bar 31 that opens rearward in a plan view is attached to the bar attachment portion 40 at its central portion 41. The left and right end portions 42 of the support bar 31 extend rearward from the central portion 41 and are connected to the lower surface of the rear portion of the main frame 11 as shown in FIG. And the support bar 31 is connected between the bar attaching part 40 and the main frame 11 by welding a connection edge part with each.

  As shown in FIG. 3, the left and right side wall portions 37 </ b> B of the down tube connecting portion 37 are formed with extending portions 36 that extend forward (project forward) from the center position in the longitudinal direction. The extending portion 36 is formed with a radiator mounting bracket 32 having a through hole 32A penetrating in the left-right direction. A bolt (not shown) is attached to the through hole 32A when the radiator 18 (see FIG. 2) is attached. ) Is inserted. The gusset 30 according to the present embodiment is formed by forging or casting, and a radiator mounting bracket 32 is integrally formed. Further, when connecting the gusset 30 to the down tube 12, a portion 30D along the peripheral edge of the radiator mounting bracket 32 is welded.

  As described above, since the radiator mounting bracket 32 is integrally formed on the gusset 30, the number of parts can be reduced, and the gusset and the bracket for mounting the radiator can be formed individually and individually. Compared with the case of welding to the down tube 12, the burden on the welding work can be reduced. Further, since the gusset 30 and the radiator mounting bracket 32 are integrally formed by casting or forging, the positioning of the radiator mounting bracket 32 with respect to the gusset 30 can be achieved with high accuracy, and as a result, the radiator 18 is attached to the radiator mounting bracket 32. It is possible to improve the assembling accuracy when assembling.

  Further, as in the case of the head pipe 10 according to the present embodiment, in the case where the upper part of the down tube 12 is sandwiched from the front and rear by the down tube tongue 10B and the gusset 30, the down tube tongue 10B and the gusset The area of the exposed portion 12 </ b> A (see FIG. 3) of the down tube 12 between 30 is reduced. Therefore, the work of welding a single bracket for attaching a radiator to such a narrow exposed portion 12A is complicated, and the configuration of the gusset 30 shown in the present embodiment is also from the viewpoint of avoiding such complexity. Exerts an excellent effect.

  Next, the configuration of the engine mounting bracket 50a will be described. As shown in FIG. 2, the lower frame 13 extends downward from the lower end portion of the down tube 12, curves in the middle, and extends rearward in a substantially horizontal direction. The engine mounting bracket 50 a is disposed at the front portion of the horizontal portion 13 </ b> A of the lower frame 13.

  FIG. 5 is a perspective view showing the left and right engine mounting brackets 50a attached to the lower frame 13 and the surrounding configuration. As shown in FIG. 5, the lower frame 13 includes a pair of left and right lower frames 131 and 132, and the engine mounting bracket 50 a includes left and right engine mounting brackets 501 and 501 disposed on the left and right lower frames 131 and 132, respectively. 502. An engine guard 60 that covers the lower part of the engine E from below is disposed between the left and right lower frames 131 and 132.

The engine guard 60 is composed of a plate member in which a plurality of punch holes for weight reduction are formed. The engine guard 60 extends in the front-rear direction along the horizontal portion 13A of the lower frame 13 and extends downward from the front portion of the lower covering portion 60A . The lower covering portion 60A covers the lower portion of the engine E from below. And a front side covering portion 60B that covers the lower front side portion of the engine E. The engine guard 60 is supported by the left and right lower frames 131 and 132 via the left and right engine mounting brackets 501 and 502 at the front position of the lower covering portion 60A .

  6 is a side view of the right side engine mounting bracket 502 shown in FIG. 5, and FIG. 7 is a front view of the engine mounting bracket 502 when viewed from the direction of arrow VII in FIG. As shown in FIG. 6, the engine mounting bracket 502 has a main body 53 that is formed in a substantially rhombus shape in a side view by a relatively thick plate member, and has a normal line extending in the left-right direction and extending in the up-down direction. A through hole 54 to the left and right is formed in the upper portion of the main body 53, and the engine E (see FIG. 2) is fixed to the engine mounting bracket 502 by a bolt (not shown) passed through the through hole 54.

  From the lower part of the main body 53 of the engine mounting bracket 502, a thick projecting portion 55 projects in the left direction (that is, toward the center in the width direction of the vehicle body). The protrusion 55 is integrally formed with the main body 53 by forging or casting, and the protrusion 55 constitutes a guard attachment 61 to which the engine guard 60 is attached. As shown in FIGS. 6 and 7, when the guard fixture 61 is cut along a plane parallel to the main body 53, the guard fitting 61 has a substantially rectangular cross section with rounded front and rear corners, and supports the engine guard 60. It has sufficient rigidity. Further, a through hole 62 penetrating in a substantially vertical direction is formed in the vicinity of the front end portion of the guard fixture 61, and the engine guard 60 is attached to the guard fixture 61 with a bolt (not shown) passed through the through hole 62. It is done.

  Further, as shown in FIG. 7, a plate-like extending portion 56 having a substantially horizontal surface is extended from the lower portion of the main body portion 53 of the engine mounting bracket 502 in the direction opposite to the protruding portion 55 described above. . The extended portion 56 is also formed integrally with the main body portion 53 by forging or casting, and the lower surface of the extended portion 56 is formed so as to match the upper surface shape of the installation location on the lower frame 132. .

  The right engine mounting bracket 502 is disposed on the upper portion of the horizontal portion 13A of the right lower frame 132 as shown in FIG. More specifically, the lower outer surface (right side surface) of the main body 53 extending in the vertical direction is in contact with the inner side surface (left side surface) of the lower frame 132, and the lower surface of the extending portion 56 is the lower frame 132. The right engine mounting bracket 502 is disposed on the lower frame 132 so as to be in contact with the upper surface. Then, a portion 50 </ b> A along the lower peripheral edge of the main body 53 and the peripheral edge of the extending portion 56 is welded, and the engine mounting bracket 502 is connected to the lower frame 132. As a result, the upper part of the main body 53 in which the through hole 54 for bolting the engine E is formed protrudes above the lower frame 132, and the guard mounting tool in which the through hole 62 for screwing the engine guard 60 is formed. 61 projects inward in the vehicle width direction.

  Note that the left engine mounting bracket 501 has a substantially symmetrical shape with the right engine mounting bracket 502 described above, and a detailed description thereof will be omitted. Further, the connection mode of the left engine mounting bracket 501 to the left lower frame 131 is the same as the above-described connection mode of the right engine mounting bracket 502, and therefore detailed description thereof will be omitted.

  Since the left and right engine mounting brackets 501 and 502 are integrally formed with the guard mounting 61, the number of parts can be reduced, and the engine mounting brackets 501 and 502 and the guard mounting 61 can be reduced. As compared with the case where each is formed as a single piece and welded to the lower frames 131 and 132, the burden on the welding work can be reduced. Further, since the engine mounting brackets 501 and 502 and the guard mounting 61 are integrally formed by casting or forging, the positioning of the guard mounting 61 with respect to the engine mounting brackets 501 and 502 can be achieved with high accuracy. The assembly accuracy when the engine guard 60 is assembled to the guard fixture 61 can be improved.

  Furthermore, the guard fixture 61 integrally formed with the engine mounting brackets 501 and 502 according to the present embodiment is excellent in rigidity because it has a substantially rectangular cross section and is relatively thick. In a motocrosser type motorcycle, an impact may be applied to the engine guard 60 from the outside during traveling, but the above-described high-rigidity guard fitting 61 is excellent in resistance to such an external impact.

  The present invention can be applied not only to the motocrosser described in the present embodiment but also to an American type or a road racer type motorcycle. In addition, the present invention can be applied to a frame having a single main frame type, two down tube types, or a single lower frame type.

  The present invention is applicable to motorcycles of motocrosser type, American type, and road racer type, and can be employed in these frames.

DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Frame 6 Steering shaft 10 Head pipe 11, 111, 112 Main frame (component)
12 Down tube (lower frame)
13, 131, 132 Lower frame (lower frame)
18 Radiator (structure)
30 Gusset 32 Radiator mounting bracket 35 Main body 36 Extension part (front extension part)
37 Down tube connection part 38 Main frame connection part 50a, 501, 502 Engine mounting bracket 50b, 50c Engine mounting bracket 53 Main body part 55 Projection part 60 Engine guard (component)
61 Guard fitting E Engine (component)

Claims (3)

A head pipe that pivotally supports the steering shaft, a lower frame that extends from the head pipe to the lower side of the vehicle body and on which the engine is mounted, a bracket that attaches a component to the lower frame, and another structure that is attached to the lower frame A connecting member for connecting an object to the lower frame,
The bracket includes an engine mounting bracket for attaching the engine to the lower frame, and the connecting member includes a guard mounting for connecting the lower frame and an engine guard that covers a lower portion of the engine, and the engine mounting The bracket and the guard fitting are integrally formed ,
The lower frame has a pair of left and right lower frames, and the engine mounting bracket is attached to the left and right lower frames to attach the engine to the lower frame, and from the main body to the left-right direction of the vehicle body A frame for a motorcycle , wherein the guard fitting is integrally formed with the projection of the engine mounting bracket . Before SL engine guard, motorcycle frame according to claim 1, characterized in that connecting the left and right of the lower frame through the bracket. The left and right lower frames have a horizontal portion extending substantially horizontally toward the rear of the engine, and the engine guard includes a lower covering portion that covers a lower portion of the engine from below and a front portion of the lower covering portion. A front covering portion extending and covering a lower front portion of the engine;
The motorcycle frame according to claim 2 , wherein the bracket supports a front position of the lower stomach portion of the engine guard at a front portion of the horizontal portion of the lower frame. .

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