JP3606495B2 - Body frame structure of motorcycle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a body frame structure of a motorcycle, and relates to a technique for reducing weight and size while securing rigidity of the body frame.
[0002]
[Prior art]
There are various types of body frames that constitute the main body of a motorcycle. Generally, a head pipe that supports a steering shaft, a main frame (down tube) that extends rearward from the head pipe and supports an engine, It is connected to the rear part of the main frame, and includes a pair of left and right side frames that support a seat on which a driver sits, a fuel tank, and the like. The body frame is most required to ensure rigidity. Conventionally, the subframe is spanned between the main frame and the side frame, or the side frame is extended forward to overlap the rear end of the main frame. By adopting a structure such as lengthening the length, the rigidity was improved.
[0003]
[Problems to be solved by the invention]
However, the above conventional structure has a problem of increasing the weight. Usually, the rear part of the main frame is equipped with parts such as an oil tank and an air cleaner because it is the central part of the vehicle body under the seat. However, there are disadvantages in that the degree of freedom is reduced and the shape and size of parts are restricted.
[0004]
The present invention has been made in view of the above-described problems of the prior art, and aims to provide a vehicle body frame structure for a motorcycle that can be reduced in weight while ensuring rigidity, and that can expand the space for arranging components. To do.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a vertical frame having an upper portion and a lower portion extending vertically from the rear end portion is fixed to the rear end portion of one main frame extending rearward from the head pipe, An upper gusset is fixed to the upper frame and the main frame, and a lower gusset is fixed to the lower frame and the main frame. The lower gusset extends in the longitudinal direction of the vehicle body. A rear arm that rotatably supports the rear wheel is attached to the rear end of the rear arm via a pivot shaft, and a rear cushion unit that cushions the swinging of the rear arm extends between the rear arm and the upper part of the vertical frame. a vehicle body frame structure of a motorcycle being passed, the upper gusset and the upper gusset said main A hollow box surrounded by an upper frame and an upper part of the vertical frame, and an upper end of the rear cushion unit is supported on the box, and the rear cushion unit is disposed on a rear surface of the upper end of the vertical frame. The upper end of is fixed .
[0006]
According to the above configuration, the upper and lower gussets improve the connection strength between the main frame and the vertical frame. Further, when the rear cushion unit expands and contracts with the swing of the rear arm, for example, a load in the front-rear direction is applied to the main frame through the vertical frame, and this load is received by the interaction of the upper and lower gussets. The upper and lower gussets can reduce the weight while ensuring the rigidity of the frame, and the periphery of the upper and lower gussets can be widened as a component arrangement space.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In a preferred embodiment, the rear arm is configured such that front end portions of a pair of left and right arm members are connected to each other by a connecting member, and one end of the rear cushion unit is attached to a plate-like bracket integrally fixed to the connecting member. The parts are connected.
In a preferred embodiment, the upper gusset is provided with a seat support member for supporting a seat on which a driver is seated.
[0008]
In a preferred embodiment, an engine is attached to the lower gusset.
Further, in a preferred embodiment, the upper gusset is made of a member having a U-shaped cross section, forms a hollow box together with the main frame and the vertical frame, and communicates with an intake duct of the air cleaner on one side surface thereof. And an air inlet for introducing outside air is formed on the other side surface.
[0009]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0010]
FIG. 1 is a side view of a motorcycle 1 to which a vehicle body frame structure according to the present invention is applied. In the figure, reference numeral F is a body frame, 5 is an engine, 18 and 21 are front wheels, rear wheels, 10 is a driver, and a tandem seat with a front and rear part on which an occupant (tandem rider) can sit, 14 is It is a body cover.
[0011]
As shown in FIGS. 2 and 3, the vehicle body frame F includes a down tube (main frame) 4 constituting a front portion of the vehicle body, a head pipe 3 fixed to the front end portion of the down tube 4, and the down tubes 4. And vertical pipes having upper and lower front gussets 30a and 30b fixed over the head pipe 3 and an upper part 72a and a lower part 72b fixed to the rear end part of the down tube 4 and extending in the vertical direction from the rear end part ( (Vertical frame) 72, an upper gusset 9 fixed over the upper portion 72a of the vertical pipe 72 and the down tube 4, a lower gusset 8 fixed over the lower portion 72b of the vertical pipe 72 and the down tube 4, and an upper gusset 9 And a seat support pipe (seat support member) 11 that is fixed to the upper portion and extends upward, and is fixed to the upper gusset 9 and extends rearward of the vehicle body. A pair of left and right upper pipe frame 12, and a respective upper pipe frame 12 and the pair of right and left lower pipe frame 13 for connecting the lower gusset 8, etc.. The body frame F is made of a metal material such as steel or aluminum, and the elements to be joined are joined together by welding.
[0012]
As shown in FIG. 1, a steering shaft 2 is passed through the head pipe 3. A steering wheel crown 15 that supports a pair of left and right front forks 17 is fixed to the upper and lower ends of the steering shaft 2, and a steering wheel 16 is fixed to the upper steering wheel crown 15. A front wheel 18 is rotatably supported at the lower end of the front fork 17. A front fender 24 that covers the upper portion of the front wheel 18 is fixed to the front fork 17. Further, a cowling 19 that covers the front of the handle 16 is fixed to the front fork 17, and a headlight 20 is attached to the cowling 19.
[0013]
The down tube 4 is composed of a single round pipe, and extends obliquely downward from the head pipe toward the rear. As shown in FIG. 3 (plan view of the vehicle body frame), the down tube 4 has a front end portion that is along the center line L of the vehicle body, but the center portion is slightly bent to the right, and the rear end portion Is bent again so as to be parallel to the center line L. The vertical pipe 72 fixed to the rear end portion of the down tube 4 is an angle member having a rectangular cross section as shown in FIG. 4, and the long side direction of the cross section is along the left-right direction and is slightly tilted backward. Thus, the central portion is joined to the down tube 4. The vertical pipe 72 has a T-shape with the down tube 4. As described above, the upper side of the joint to the down tube 4 is an upper part 72 a and the lower side is a lower part 72 b.
[0014]
As shown in FIGS. 2 and 3, the lower gusset 8 is composed of a pair of left and right plate members 8a and 8b, and these plate members are fixed so as to face each other across the lower portion 72b of the vertical pipe 72 and the down tube 4. Yes. The lower gusset 8 is a plate material having a substantially L-shaped cross section, the longitudinal direction is along the vertical direction of the vehicle body, the upper edge portion is aligned with the side surface of the rear end portion of the down tube 4, and the upper rear edge portion is a vertical pipe. The L-shaped end portions of the left and right plate members overlap each other on the rear side of the vertical pipe while being aligned with the side surface of the lower portion 72b and fixed by welding.
[0015]
On the other hand, as shown in FIGS. 2 to 4, the upper gusset 9 fixed over the upper portion 72a of the vertical pipe 72 and the down tube 4 includes an upper plate portion 9a and a pair of side plate portions 9b facing each other. It is a member having a U-shaped cross section and a triangular shape as a whole. In the upper gusset 9, two sides of the side plate portion 9b are fixed to the upper portion 72a of the vertical pipe 72 and the rear end portion of the down tube 4 by welding. In this fixed state, the upper plate portion 9a is along the longitudinal direction of the vehicle body, and the inside is surrounded by the upper plate portion 9a, both side plate portions 9b, the down tube 4 and the upper portion 72a of the vertical pipe 72, and is a hollow box. Is forming. The upper end portion of the rear cushion unit 71 (FIGS. 1 and 6) is supported by the box, and the upper end portion of the rear cushion unit 71 is fixed to the rear surface of the upper end portion of the vertical pipe (vertical frame) 72. That is, as shown in FIGS. 2 and 4, an upper cushion bracket 31 having a U-shaped cross section protruding to the rear of the vehicle body is fixed to an upper end portion of the vertical pipe 72 constituting the box .
[0016]
As shown in FIGS. 1 and 5, the front end of the rear arm 22 is swingably attached to the lower gusset 8 made of the left and right plate members via a pivot shaft 75 extending in the left-right direction. These rear arms 22 include a pair of left and right arm members 22a and 22b, extend rearward from the pivot shaft 75, and a rear wheel 21 is rotatably supported at a rear end thereof. Incidentally, FIG. 5 shows a hub 21a constituting the rear wheel 21, and a chain sprocket 32 is fixed to an end surface on the left side (lower side in FIG. 5) of the hub 21a. A drive chain 33 wound around a drive sprocket (not shown) of the engine 5 is wound around the chain sprocket 32. The upper winding side of the drive chain 33 is covered with a chain case 23 fixed to the left rear arm 22.
[0017]
As shown in FIGS. 5 and 6, the front end portion of the rear arm 22 near the pivot shaft 75 is connected to the connecting member 34 formed in a box shape, and is substantially spaced apart from the rear side of the connecting member 34. They are connected to each other via a U-shaped cross pipe 35. Further, the connecting member 34 and the cross pipe 35 are connected to each other via a lower cushion bracket (plate-shaped bracket) 74 formed by bending a sheet metal into a U-shape. The lower cushion bracket 74 is disposed at the center in the width direction of the vehicle body, and is fixed to the lower surface of the connecting member 34 and the upper surface of the central portion of the cross pipe 35. A hole 74 a is formed in the lower cushion bracket 74. The upper and lower cushion brackets 31 and 74 are fixed to the upper and lower ends of a rear cushion unit 71 that cushions the swinging of the rear arm 22, respectively.
As shown in FIG. 2, the vertical pipe 72 has a linear shape between the pivot shaft 75 that supports the rear arm 22 and the upper cushion bracket 31 that is a portion that fixes the upper end portion of the rear cushion unit 71.
[0018]
As shown in FIG. 7, the rear cushion unit 71 itself has a generally known structure including a coil spring 80 and a damper 81 that suppresses the resilient force of the coil spring 80. The parts are provided with mounting rings 81a and 81b, respectively. The rear cushion unit 71 has an upper end mounting ring 81a fixed to the upper cushion bracket 31 and a lower end mounting ring 81b fixed to the lower cushion bracket 74 by bolts 82 and nuts 83, respectively. A shim 84 is interposed between the upper cushion bracket 31 and the bolt 82 and between the lower cushion bracket 74 and the bolt 82.
[0019]
Thus, the rear cushion unit 71 has a lower end fixed to the rear arm 22 via the lower cushion bracket 74, the connecting member 34 and the cross pipe 35, and an upper end connected to the vertical pipe 72 via the upper cushion bracket 31. In other words, the rear cushion unit 71 is stretched over the rear arm 22 and the upper portion 72a of the vertical pipe 72.
[0020]
As shown in FIG. 2, the upper and lower portions of the front portion of the lower gusset 8 are engine brackets 36 and 37. The engine 5 is bolted to these engine brackets 36 and 37 and another engine bracket 6 fixed to the central portion of the down tube 4. As shown in FIG. 1, an exhaust muffler 38 that is routed rearward of the vehicle body is connected to the engine 5.
[0021]
Further, as shown in FIGS. 1 and 6, the lower gusset 8 is provided with a main stand 7 for stably supporting the vehicle body during parking and a footrest 39 on which the driver's feet are placed. As shown in FIGS. 6 and 8, the main stand 7 includes a pair of left and right stand pipes 46 connected to each other by a reinforcing pipe 45, and the base end portion of each stand pipe 46 pivots to the lower end portion of the lower gusset 8. It is rotatably attached via 47. The main stand 7 is rotated forward from the spring-up position (storage position) shown in FIG. 6 and the spring-up position shown in FIG. 1 by a spring 48 spanned between the left stand pipe 46 and the lower gusset 8. It is held at two positions, the position that supports the vehicle body. As shown in FIG. 6, the footrest 39 is attached to the front of the lower end portion of the lower gusset 8 via a stay 40.
[0022]
Next, the upper gusset 9 will be described.
As shown in FIGS. 2 and 3, the front end portions of the pair of left and right upper pipe frames 12 are fixed to the rear end portion of the upper plate portion 9 a of the upper gusset 9. These upper pipe frames 12 extend obliquely from the joint to the upper gusset 9 to the outside of the vehicle body, and then extend rearward of the vehicle body with a center line L (see FIG. 3) of the vehicle body as a symmetry line. The rear end portion 12a of the upper pipe frame 12 is bent upward, and the rear bracket 50 is fixed between the rear end portions 12a.
[0023]
As shown in FIG. 1, a grab bar 41 that is held by a tandem rider is attached to the rear bracket 50. A rear fender 25 covering the upper portion of the rear wheel 21 is fixed to the rear end portion 12 a of the upper pipe frame 12, and a tail lamp 43 is provided between the rear fender 25 and the grab bar 41. The lower pipe frame 13 is spanned and fixed between the center portion of each upper pipe frame 12 and the upper portion of the lower gusset 8. A handle portion 12b is formed behind the joint portion of the left upper pipe frame 12 with the lower pipe frame 13 to lift the vehicle body and support the vehicle body with the main stand 7. In addition, a tandem footrest 49 on which a tandem rider's foot is placed is attached to the center of the left and right lower pipe frames 13 via a stay 73.
[0024]
As shown in FIGS. 1 and 2, the seat support pipe 11 extending upward is fixed to the center of the upper plate portion 9 a of the upper gusset 9. The lower end of the front end of the seat 10 is hinged to the upper end of the seat pipe 11 via a pivot shaft 11a. The seat 10 is supported by a fuel tank 63 supported on the left and right upper pipe frames 12, and the rear end portion thereof is supported by the rear bracket 50 and is detachably engaged through a seat lock.
[0025]
Also, an air cleaner 51 is disposed on the left side of the upper gusset 9 as shown in FIGS. 9 and 10, and an oil tank 60 is disposed on the upper side to the right side as shown in FIG. ing.
[0026]
As shown in FIG. 9, the air cleaner 51 includes an air cleaner case 52, an element 54 that divides the air cleaner case 52 into an upstream chamber 53 a and a downstream chamber 53 b, and the outside air and the upstream chamber through the downstream chamber 53 b and the element 54. An intake duct 55 that communicates with 53a, and an intake manifold that connects the downstream chamber 53b and the carburetor 28 of the engine 5 are provided. As shown in FIG. 10, the air cleaner 51 has flanges 52 a and 52 b formed at the front end portion and the rear end portion of the air cleaner case 52, which are screwed to the left side plate portion 9 b and the lower pipe frame 13 of the upper gusset 9, respectively. It has been stopped. Round holes 57 and 58 are formed in both side plate portions 9b of the upper gusset 9, respectively. In this case, the round hole 57 of the right side plate portion 9 b is located slightly above, and the round hole 58 of the left side plate portion 9 b is located behind and below the right round hole 57. And the edge part of the intake duct 55 of the air cleaner 51 is inserted in the round hole 58 of the left side plate part 9b. That is, the inside of the upper gusset 9 is an air cleaner chamber 9A (FIG. 9) communicating with the intake duct 55, and the right circular hole 57 is an intake port for introducing outside air into the air cleaner chamber 9A. The hole 58 is a communication port to the intake duct 55 of the air cleaner 51. In this air cleaner 51, outside air is introduced into the air cleaner chamber 9 </ b> A inside the upper gusset 9 from the air inlet (round hole 57) of the right side plate portion 9 b of the upper gusset 9, and from there to the left round hole 58. Through the intake duct 55 and enters the upstream chamber 53a. Next, outside air is filtered by passing through the element 54, enters the downstream chamber 53 b, and is introduced into the carburetor 28 from the intake manifold 56.
[0027]
The oil tank 60 is mounted on and mounted on the upper gusset 9, and as shown in FIG. 1, a main body portion 60a mounted on the upper gusset 9, and a right side of the upper gusset 9 hanging from the main body portion 60a. Side portion 60b. The main body 60 a covers the air cleaner 51. In the oil tank 60, a flange (not shown) formed at the upper front end of the main body 60a is fixed to the seat support pipe 11, and the bottom is held by a bracket (not shown) on the vehicle body frame F side. The upper position is maintained.
[0028]
Further, as shown in FIG. 1, a battery 62 and a fuel tank 63 are disposed behind the oil tank 60 and between the seat 10 and the upper pipe frame 12. The fuel tank 63 has four corners of flanges protruding from the side surfaces thereof, which are received by the receiving brackets 12c (FIG. 3) provided at the front and rear ends of the left and right upper pipe frames 12, respectively. It is fixed. The vehicle body frame F, the engine 5, the air cleaner 51 attached to the vehicle body frame F, the oil tank 60, the battery 62, the fuel tank 63, and the like are covered with the vehicle body cover 14 shown in FIG. The vehicle body cover 14 covers the side of the upper part of the down tube 4 and the engine 5 and connects the left and right front side covers 26 having the under cowl 27 and the upper ends of the front side cover 26 to the upper side of the down tube 4. A front top cover 64 that covers the air cleaner 51, and an air cleaner 51 and an oil tank 60 attached to the upper gusset 9, and a side portion of a battery 62, a fuel tank 63, an upper pipe frame 12, and other parts disposed below the seat. The rear side cover 70, a sprocket cover 65 that covers the side of the drive sprocket of the engine 5, and a tail cover 66 that covers the top of the tail lamp 43 are configured. These covers 26, 64, 70, 65, 66 are fixed to mounting portions provided at appropriate positions of the vehicle body frame F by means such as screwing. For example, the front top cover 64 is fixed together with an attachment portion 67 provided at the front end of the upper plate portion 9a of the upper gusset 9 together with the lower front cover 64a.
[0029]
Next, the operation of the body frame structure described above and the effects accompanying it will be described. Paying attention to the center of the vehicle body below the front portion of the seat 10, the vertical pipe 72 is fixed to the rear end portion of one down tube 4, and the upper gusset extends over the upper and lower portions 72 a and 72 b of the vertical pipe 72 and the down tube 4. 9 and the lower gusset 8 are fixed. With this frame configuration, the center of the vehicle body becomes extremely slim and light weight is achieved. Further, the space for arranging the parts such as the air cleaner 51 and the oil tank 60 is widened. As a result, the layout of these parts and the degree of freedom of the shape and size of the parts are remarkably improved. In the present embodiment, the air cleaner 51 is disposed on the left side of the upper gusset 9, and the oil tank 60 has a shape extending from the upper side (main part 60a) to the right side (side part 60b) of the upper gusset. That is, the space around the upper gusset 9 is effectively used, and the capacity thereof increases.
[0030]
Further, according to the vehicle body frame F, the connection strength between the down tube 4 and the vertical pipe 72 is improved by the upper and lower gussets 9 and 8.
Further, when the rear wheel 21 moves up and down due to road surface irregularities or the like, the rear arm 22 swings, and the rear cushion unit 71 expands and contracts accordingly. As a result, for example, a load in the front-rear direction is applied to the down tube 4 via the upper cushion bracket 31 and the vertical pipe 72, but this load is received by the upper and lower gussets and the durability is increased.
As a result, although the structure is simple, the rigidity of the vehicle body frame F is greatly improved, and an equipment such as an excessive reinforcing frame is not required.
Since the lower cushion bracket 74 is a plate-like member formed by bending a sheet metal, the connecting structure with the rear cushion unit 71 is simplified, the manufacturing is facilitated, and the weight and the size are reduced.
[0031]
Further, the upper gusset 9 is effectively used as a mounting bracket for mounting components mounted on the upper part of the vehicle body such as the seat 10, the air cleaner 51, the oil tank 60, the front top cover 64, and the front lower cover 64a. This is also true for the lower gusset 8. The lower gusset 8 is provided with components mounted on the lower part of the vehicle body such as the main stand 7 and the footrest 39, and the engine is mounted through the mounting holes 36 and 37. It is also used as an engine bracket to be supported, and there is no need for a dedicated bracket or the like for mounting these parts. Further, the upper gusset 9 constitutes a hollow box body, and the inside of the upper gusset 9 is also used as an air cleaner chamber 9 </ b> A for temporarily storing outside air introduced into the air cleaner 51. For this reason, the exclusive component of an air cleaner chamber is not required.
As a result, the number of parts can be reduced and the cost can be reduced, and the slimming and weight reduction of the vehicle body can be promoted.
[0032]
【The invention's effect】
As described above, according to the motorcycle body frame structure of the present invention, the weight can be reduced while the rigidity is ensured, and the layout of the parts and the parts can be increased by expanding the part placement space in the center part of the car body. The degree of freedom of the shape and size of the is improved.
[Brief description of the drawings]
FIG. 1 is a side view of a motorcycle to which a vehicle body frame structure according to an embodiment of the present invention is applied.
FIG. 2 is a side view of a vehicle body frame.
FIG. 3 is a plan view of a vehicle body frame.
4 is a cross-sectional view taken along the line CC in FIG. 2;
FIG. 5 is a plan view mainly showing a rear arm.
FIG. 6 is a side view mainly showing a lower part of a rear portion of the vehicle body.
FIG. 7 is a side view of the rear cushion unit.
FIG. 8 is a plan view showing a main part of the main stand.
FIG. 9 is a plan view showing an air cleaner attached to the upper gusset.
FIG. 10 is a side view of the same.
[Explanation of symbols]
4 ... Down tube (main frame), 7 ... Main stand, 8 ... Lower gusset, 9 ... Upper gusset, 9A ... Air cleaner chamber, 10 ... Seat, 11 ... Seat support pipe (seat support member), 14 ... Body cover, 21 ... rear wheel, 22 ... rear arm, 34 ... connecting member, 36, 37 ... engine bracket, 39 ... footrest, 51 ... air cleaner, 55 ... air intake duct, 57 ... round hole (intake port), 58 ... round hole (communication port) , 60 ... Oil tank, 71 ... Rear cushion unit, 72 ... Vertical pipe (vertical frame), 72a ... Upper part of vertical pipe, 72b ... Lower part of vertical pipe, 74 ... Lower cushion bracket (plate bracket), 75 ... Pivot , F ... Body frame.

Claims (6)

A vertical frame having an upper portion and a lower portion extending in the vertical direction from the rear end portion is fixed to the rear end portion of one main frame extending rearward from the head pipe, and extends over the upper portion and the main frame of the vertical frame. An upper gusset is also fixed over the lower part of the vertical frame and the main frame, respectively.
A rear arm that extends in the front-rear direction of the vehicle body and rotatably supports the rear wheel at the rear end is attached to the lower gusset via a pivot shaft so as to be swingable.
A vehicle body frame structure of a motorcycle in which a rear cushion unit for buffering the swing of the rear arm is stretched over the rear arm and the upper portion of the vertical frame ,
The upper gusset forms a hollow box surrounded by the upper gusset, the main frame, and the upper part of the vertical frame,
The upper end of the rear cushion unit is supported on this box,
A vehicle body frame structure for a motorcycle , wherein an upper end portion of the rear cushion unit is fixed to a rear surface of the upper end portion of the vertical frame . The body frame structure for a motorcycle according to claim 1, wherein the vertical frame has a linear shape between a pivot shaft that supports the rear arm and a portion that fixes an upper end portion of the rear cushion unit. The rear arm is configured by connecting front end portions of a pair of left and right arm members with a connecting member, and one end portion of the rear cushion unit is connected to a plate-like bracket fixed integrally to the connecting member. The body frame structure of a motorcycle according to claim 1 or 2 , characterized by the above-mentioned. The body frame structure of a motorcycle according to any one of claims 1 to 3, wherein a seat support member for supporting a seat on which a driver is seated is attached to the upper gusset. The body frame structure of a motorcycle according to any one of claims 1 to 4 , wherein an engine is attached to the lower gusset. Wherein the gusset is made of members of U-shaped cross section, said constitutes a hollow box body together with the main frame and the vertical frame has a communication port communicating with the intake duct d Akurina on one side thereof, the other The body frame structure for a motorcycle according to any one of claims 1 to 5, wherein an intake port for introducing outside air is formed on a side surface.

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