JP2006312348A - Motorcycle body frame structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motorcycle body frame structure capable of effectively improving the dimensional accuracy, layout or the like. <P>SOLUTION: Right and left head pipe parts 11A, a pair of right and left main frame parts 11b extending backwardly and downward from the head pipe parts 11A, and a pair of right and left pivot bracket parts 11C connected to rear ends of the right and left main frame parts 11B are connected to each other to form an integrated product, and the head pipe parts 11A are fastened to and joined with each other at a front end of a body frame 10. A power unit 110 is suspended by an engine suspension unit in a holding manner from the right and left sides, and the right and left pivot bracket parts 11C are connected to each other at a rear end of the body frame 10 via a supporting shaft 19. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure of a body frame particularly in a motorcycle.

  Regardless of the material of the body frame of a motorcycle, a bridge member is generally provided between the left and right sides of the frame. This bridge member is welded by a welding frame, and may be assembled by bolts without using welding.

  For example, the body frame of Patent Document 1 includes a pair of left and right main frames and a pair of left and right rear arm brackets provided below the main frames and supporting the rear arms in the middle of the upper and lower sides. A connecting member as a bridge member having an axial center extending left and right is disposed between the rear arm brackets, and the left and right rear arm brackets are integrally connected by welding the connecting members.

Japanese Patent Publication No. 4-51395

  However, in the welding frame, there is a problem such as deformation of the frame due to heat at the time of welding by welding the bridge member, and some measures must be taken to prevent it. Further, in the case of a body frame assembled using bolts, processing for attaching a bridge member is required, and the layout of the bridge member must be constrained by any part of the body frame, that is, a place where the bridge member can be processed.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a body frame structure for a motorcycle that can effectively improve dimensional accuracy, layout, and the like.

  A motorcycle body frame structure according to the present invention includes a left and right head pipe portion that forms a head pipe that swingably supports a steering shaft, and a pair of left and right main frame portions that extend rearward and downward from the head pipe portion, A pair of left and right pivot brackets connected to the rear ends of the left and right main frame parts and swingably supporting the swing arm in the middle of the upper and lower parts are integrally molded on the left and right sides, and left and right at the front end of the body frame. The head pipe portion is brought into contact with the joint surface to be fastened and joined, and the power unit is suspended from right and left by an engine suspension portion provided at an appropriate position of the main frame portion and the pivot bracket portion. The left and right pivot brackets are connected via a support shaft for supporting the rear cushion unit at the rear end of the frame. And wherein the door.

Further, in the motorcycle body frame structure of the present invention, the power unit is suspended so as to be sandwiched from right and left by engine suspension portions provided at a plurality of appropriate positions of the main frame portion and the pivot bracket portion. And

  Further, in the vehicle body frame structure of the motorcycle according to the present invention, a connecting hole whose axial center is directed to the left and right is formed at the lower end portion of the left and right pivot bracket portions, and the corresponding left and right end portions of the support shaft correspond to the corresponding connecting holes. The rear end portions of the vehicle body frame are integrally connected with the left and right pivot bracket portions.

  Further, in the vehicle body frame structure of the motorcycle of the present invention, a rear frame extending from the rear upper part of the vehicle body frame to the rear upper side and detachably formed is coupled, and a bridge member provided at a front end portion of the rear frame, A bracket for supporting the upper end of the rear cushion unit is provided.

  Further, in the body frame structure of the motorcycle according to the present invention, the engine suspension portion is disposed in the vicinity of the attachment portion of the support shaft and the bridge member in the body frame.

  According to the present invention, the left and right sides of the vehicle body frame are each integrally molded by casting, and the bridge member that connects them is fastened by screwing rather than by welding, so that the dimensional accuracy is high, resulting in stable steering. A good frame can be formed.

  In addition, the engine suspension part is formed integrally with the left and right body frames, the pivot pipe of the swing arm that acts as a head pipe part and a bridge member that joins the left and right body frames, the support shaft of the cushion lever, the engine case, A joint surface corresponding to the engine cylinder portion is machined based on a common processing reference surface. Since a bonding surface with high dimensional accuracy can be formed, the bonding strength by fastening each bonding portion can be greatly increased. That is, a vehicle body frame having high rigidity, good dimensional accuracy and excellent steering stability can be formed.

  Further, since the bridge member can be attached together with the rear frame, it is possible to provide a body frame that is easy to assemble and inexpensive. In addition, the rigidity of the pivot bracket portion that supports the front end of the swing arm having a high contribution to the torsional rigidity of the vehicle body frame in a swingable manner can be effectively increased.

A preferred embodiment of a body frame structure for a motorcycle according to the present invention will be described below with reference to the drawings.
First, an overall configuration of the motorcycle 100 according to the present embodiment will be schematically described. In FIG. 1, two front forks 101 supported by a head pipe portion 11A so as to be turnable to the left and right are provided at a front portion of a vehicle body frame 10 to be described later made of, for example, steel or aluminum alloy. A handle bar 102 is fixed to the upper end of the front fork 101, and grips 103 are provided at both ends of the handle bar 102. A front wheel 104 is rotatably supported on the lower portion of the front fork 101, and a front fender 105 is fixed so as to cover the upper portion of the front wheel 104. The front wheel 104 has a brake disc 106 that rotates integrally with the front wheel 104.

  A swing arm 107 is swingably provided at the rear of the body frame 10, and a rear cushion unit 108 is indirectly mounted between the body frame 10 and the swing arm 107. A rear wheel 109 is rotatably supported at the rear end of the swing arm 107, and the rear wheel 109 is rotationally driven via a driven sprocket around which a chain (not shown) is wound.

  The vehicle body frame 10 has a main frame portion 11B and a pivot bracket portion 11C, and a power unit 110 is mounted via an engine mount (engine suspension portion) set to them as will be described later. The power unit 110 is supported by the body frame 10 so as to be covered from both the left and right sides, and a fuel tank 111 is disposed above the power unit 110. In the space below the fuel tank 111, a fuel supply device (carburetor or fuel injection device) and an air purification device which are intake devices are disposed. The fuel unit is supplied to the power unit 110 by the fuel supply device and the air purification device, and the exhaust gas after combustion is exhausted through the exhaust pipe 112.

  The plurality of exhaust pipes 112 extends downward from the front portion of the power unit 110, gathers at a lower portion thereof, and extends obliquely upward from the rear portion of the power unit 110 as an exhaust pipe 113. A muffler 114 (FIG. 2) is coupled to the rear end of the exhaust pipe 113. A radiator 115 is disposed at the front of the power unit 110.

  A rear frame 12 extends from the vicinity of the rear portion of the vehicle body frame 10 in a form that is inclined obliquely upward and rearward. The rear frame 12 includes a seat rail 13 and a seat rail pillar tube 14 so as to support the seat 116 and the like. As will be described later in detail, the rear frame 12 is mainly coupled to the main frame portion 11B to ensure rigidity.

  Further, in FIG. 1, a headlamp unit 117 is supported at the front end portion of the body frame 10, and the headlamp unit 117 is mounted with a meter unit including a speedometer, a tachometer, various indicator lamps and the like. A rear cowling 118 is attached to the lower side of the seat 116 so as to cover the rear frame 12 and the like, and a grab bar 119, a tail lamp 120 and the like are disposed near the rear end thereof.

  Further, the inner fender 121 is supported at an appropriate position of the swing arm 107 so as to cover the vicinity of the upper front portion of the rear wheel 109, and the rear fender 122 is supported at an appropriate position of the rear frame 12 so as to cover the upper portion of the rear wheel 109. . A blinker lamp 123 is mounted on the rear fender 122. Moreover, it has the virion footrest 126 attached to the footrest 124 and footrest bracket 125 for drivers | operators.

  FIG. 2 (and FIG. 3) shows a configuration example around the vehicle body frame 10. The body frame 10 is integrated in a pair of left and right, but the head pipe portion 11A, the main frame portion 11B, and the pivot bracket portion 11C on the left and right sides are typically formed as an integrally molded product by casting. As shown in FIG. 2, the head pipe portion 11A is located at the front apex, the main frame portion 11B extends from the head pipe portion 11A so as to be inclined rearward and obliquely downward, and the pivot bracket portion 11C is further extended to the main frame. It extends downward from the vicinity of the rear end of the portion 11B. Further, as a result of the pair of left and right being coupled, the vehicle body frame 10 has a substantially deformed U-shape as shown in FIG. 3A, and a wide space is secured inside thereof.

  The head pipe portion 11A supports the left and right semi-cylindrical bodies so as to swing left and right so as to sandwich the steering shaft (steering stem) provided on the front fork 101 from the left and right by integrating the left and right semicylindrical bodies. In this example, the left and right semi-cylindrical bodies of the head pipe portion 11A are fastened to each other by six bolts 15 as shown in FIG. 2, thereby constituting the head pipe portion 11A.

  Here, as shown in FIG. 3B, the vehicle body frame 10 generally has a channel-shaped (substantially U-shaped) cross section from the main frame portion 11B to the pivot bracket portion 11C. A plurality of reinforcing ribs 16 are disposed at appropriate directions and intervals inside the channel shape, and high rigidity and strength are ensured.

  The power unit 110 is supported by the body frame 10 as described above. In this case, the engine cylinder part (near the cylinder head) and the engine case part (near the crankcase) of the power unit 110 are left and right on the lower edge part of the main frame part 11B and the upper and lower ends of the front edge part of the pivot bracket part 11C. Engine suspensions 17A, 17B, 17C, and 17D are integrally provided so as to be sandwiched between the two. As a result, the power unit 110 is supported, and the left and right sides of the vehicle body frame 10 are integrally connected to each other and have high rigidity.

  A pivot shaft 18 that supports the front end of the swing arm 107 so as to be swingable up and down is provided in the middle of the pivot bracket portion 11C. In this example, the rear cushion unit 108 is mounted in the vicinity of the rear portion of the pivot bracket portion 11C, but is appropriately deviated to the left side. This is to prevent interference with the exhaust pipe 113.

  The lower end of the rear cushion unit 108 is supported by a cushion lever 127. Between the left and right pivot bracket portions 11C, there is disposed a shaft member (support shaft 19 that supports the one end of the cushion lever 127 of the rear cushion unit 108 so as to be freely slidable vertically. At the lower end of the bracket portion 11C, connecting holes 20 whose axial centers are directed to the left and right are formed, and the left and right ends of the support shaft 19 of the cushion lever 127 are fitted into the corresponding connecting holes 20 and fastened. Thus, the rear end portions of the left and right pivot bracket portions 11C are integrally connected.

  The rear frame 12 extends from the rear upper part of the vehicle body frame 10 to the rear upper part and is detachable. Here, FIG. 4 shows a configuration example of the rear frame 12. The seat rail 13 is composed of a pair of left and right, and a bridge member 21 is horizontally mounted on the front end portion in the left-right direction. Further, mounting brackets 22 extend forward from the front end portion where the bridge member 21 is horizontally mounted, and these brackets 22 are fastened to mounting portions 23 provided on the left and right main frame portions 11B.

  The seat rail pillar tube 14 is configured as a pair of left and right, and is disposed below the seat rail 13. A bridge member 24 is horizontally mounted on the front end of the seat rail pillar tube 14 in the left-right direction. Both ends of the bridge member 24 are fastened to attachment portions 25 provided near the boundary between the main frame portion 11B and the pivot bracket portion 11C.

  Thus, the bridge member 24 connects the attachment portions 25 corresponding to the front ends of the left and right seat rail pillar tubes 14. The upper end of the rear cushion unit 108 whose lower end is supported by the other end of the cushion lever 127 is attached to the bridge member 24. That is, a rear cushion unit mounting bracket 26 is provided at a portion that is moderately biased to the left side of the bridge member 24, and the upper end of the rear cushion unit 108 is coupled to the bracket 26. Note that another bridge member 27 is also laid across the rear portion of the seat rail 13.

  Here, the attachment of the bridge member 24 at the front end of the seat rail pillar tube 14 provided with the support shaft 19 of the cushion lever 127 provided on the pivot bracket portion 11C of the body frame 10 and the attachment bracket 26 of the rear cushion unit 108 is provided. In close proximity to the part 25, engine suspension parts 17C and 17D for suspending the engine case part of the power unit 110 are arranged.

  In the above configuration, the left and right sides of the body frame 10 are each integrally molded by casting. In this case, the left and right head pipe portions 11 </ b> A are fastened to each other at the front portion of the vehicle body frame 10, and the left and right pivot bracket portions 11 </ b> C are connected to each other through the support shaft 19. In the main frame portion 11B, the power unit 110 is supported via the engine suspension portions 17A, 17B, 17C, and 17D, and the left and right sides of the body frame 10 are integrally connected as a whole. These members substantially function as a bridge for connecting the left and right sides of the body frame 10, that is, the body frame 10 itself can secure high rigidity without having a bridge member.

  Furthermore, by joining the rear frame 12, bridge members 21 and 24 for connecting the left and right of the vehicle body frame 10 are added, and higher rigidity is obtained. In this case, the bridge members 21 and 24 that connect the left and right of the body frame 10 are fastened not by welding but by screws. Therefore, it is possible to form a frame having higher dimensional accuracy than that integrally joined by welding and, as a result, good steering stability.

  Further, the engine suspension portions 17A, 17B, 17C, and 17D are integrally formed with the left and right body frames 10, and the pivots of the swing arm 107 that acts as a head pipe portion 11A that joins the left and right body frames 10 and a bridge member. Since the joint surfaces corresponding to the shaft 18, the support shaft 19 of the cushion lever 127, and the engine case and the engine cylinder portion are machined based on a common processing reference surface, a joint surface with high dimensional accuracy can be formed. And the joint strength by fastening of each junction part can be raised significantly. That is, the vehicle body frame 10 having high rigidity, good dimensional accuracy, and excellent steering stability can be formed.

  Further, since the bridge members 21 and 24 can be attached together with the rear frame 12, it is possible to provide the body frame 10 that is easy to assemble and is inexpensive. In addition, the rigidity of the pivot bracket portion 11C that supports the front end of the swing arm 107 having a high contribution to the torsional rigidity of the vehicle body frame 10 in a swingable manner can be effectively increased.

As mentioned above, although this invention was demonstrated with embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
For example, the number of engine suspensions and the like can be increased or decreased as necessary, and the same effects as those in the above embodiment can be obtained.

1 is a side view of a motorcycle according to an embodiment of the present invention. It is a side view showing an example of composition around a body frame concerning an embodiment of the present invention. It is the top view and sectional view of a body frame concerning an embodiment of the present invention. It is a figure which shows the structural example of the rear frame which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Body frame 11A Head pipe part 11B Main frame part 11C Pivot bracket part 12 Rear frame 13 Seat rail 14 Seat rail pillar tube 15 Bolt 16 Reinforcement rib 17A, 17B, 17C, 17D Engine suspension part 18 Pivot shaft 19 Support shaft 20 Connection Holes 21 and 24 Bridge member 22 Brackets 23 and 25 Mounting portion

Claims (5)

Connected to the left and right head pipe portions that form a head pipe that swingably supports the steering shaft, a pair of left and right main frame portions that extend rearward and downward from the head pipe portion, and the rear ends of the left and right main frame portions And a pair of left and right pivot brackets that swingably support the swing arm in the middle of the upper and lower parts as an integrally molded product on both the left and right sides,
At the front end of the vehicle body frame, the joint surfaces of the left and right head pipe portions are brought into contact with each other and fastened and joined, while the rear end portion of the vehicle body frame passes through a support shaft for supporting the rear cushion unit. A body frame structure for a motorcycle, wherein the pivot bracket portion is connected.   2. The body frame of a motorcycle according to claim 1, wherein the power unit is suspended from left and right by engine suspension portions provided at a plurality of appropriate positions of the main frame portion and the pivot bracket portion. Construction.   The left and right pivot bracket portions are respectively formed with connecting holes whose axial centers are directed to the left and right, and the left and right end portions of the support shaft are fitted into the corresponding connecting holes and fastened. 3. The body frame structure for a motorcycle according to claim 1, wherein a rear end portion of the body frame is integrally connected by a portion.   A rear frame that extends from the rear upper part of the vehicle body frame to the rear upper part and is detachable is coupled, and a bracket that supports the upper end of the rear cushion unit is provided on the bridge member provided at the front end of the rear frame. The body frame structure of a motorcycle according to any one of claims 1 to 3.   5. The vehicle body frame structure for a motorcycle according to claim 4, wherein the engine suspension portion is disposed in proximity to a mounting portion of the support shaft and the bridge member in the vehicle body frame.

Images