JP2013121769A - Fastening structure of vehicle body frame - Google Patents

Abstract

Provided is a body frame fastening structure capable of suppressing the occurrence of an undesired fastening stress at a fastening portion even when a part has a manufacturing error, an assembly error, or the like.
A fastening structure M for fastening a subframe 10 constituting a part of a vehicle body frame FR to a main frame 1 constituting another part of the vehicle body frame FR by a bolt 64. A fixing hole 48 that is an insertion hole for the bolt 64 is provided in the main frame 1 with a fixing hole 56 that is a screw hole, and the bolt 64 is inserted through the fixing hole 48 through a gap to be fixed. Spherical seats 46 and 54 are formed around the hole 48 and the fixing hole 56 to be brought into pressure contact with each other by fastening.
[Selection] Figure 5

Description

  The present invention relates to a fastening structure for fastening a member constituting a part of a vehicle body frame to a member constituting another part of the vehicle body frame.

  For example, in a vehicle such as a motorcycle, there is a structure in which a subframe that reinforces the main frame is attached to the side of the main frame that supports the engine (for example, Patent Document 1). Such a subframe is generally fixed to a main frame with bolts.

JP 2006-062646 A

  Members such as the main frame and the subframe are often mass-produced products by welding and casting, and include manufacturing errors larger than machining. Further, when assembling these members, an assembly error may occur. Due to such an error, the mounting surfaces of the main frame and the sub frame may be inclined, and if the bolt is tightened in such a state, an undesired tightening stress may be generated.

  The present invention has been made in view of the above problems, and even when there is a manufacturing error or an assembly error in a part, the fastening of the body frame that can suppress the occurrence of an undesired fastening stress at the fastening part. The purpose is to provide a structure.

  In order to achieve the above object, a fastening structure for a vehicle body frame according to one configuration of the present invention comprises: a fixed member that forms part of a vehicle body frame and has a fixed hole formed of a through hole; The other part of the frame constitutes a fixing member in which a fixing hole for fixing the fixing member is formed, a shaft portion having a smaller diameter than the fixing hole, and the fixing hole. A fastening unit having a large-diameter head, and the fastening unit is fastened by the head by inserting the shaft portion through the fastening hole and fastening on the fixing member side. A member is pressed against the fixing member to fasten the fixed member and the fixing member, and a first contact surface between the fixed member and the fixing member is a virtual surface on each first contact surface and the first contact surface The first predetermined distance is moved in one direction of the center line from the intersection with the center line of the fixing hole. A first fitting portion that is curved along a first curved surface with a first center point as a center of curvature; and a second contact surface between the fixed member and the bolt unit head includes Along the second curved surface with the second center point moved from the intersection of the virtual surface on the second abutting surface and the center line of the fixing hole in one direction of the center line as a center of curvature. The 2nd fitting part which curves is constituted.

  According to this configuration, since the fixed member is pressed along the curved surface by the fastening unit head and the fixing member, the fixed member becomes the fixing member by an amount corresponding to the gap between the shaft portion of the fastening unit and the fixing hole. Even if it is inclined, it can be fastened. As a result, even if there is a dimensional error, assembly error, etc. between the fixed member and the fixed member and they are relatively inclined, they can be connected to each other in an inclined state, and undesired tightening stress is generated. Can be prevented.

  In the present invention, the to-be-fixed member has an elongated shape, and both end portions in the longitudinal direction are fixed to separate members, and the fastening structure is used only at one end portion of these both end portions. It is preferable that According to this configuration, both high strength and dimensional error tolerance can be achieved by allowing an error at one end and carrying a strength at the other end.

  In the present invention, the first and second curved surfaces are preferably spherical. According to this configuration, since the first and second curved surfaces are spherical, it is possible to effectively absorb multi-directional inclinations between the fixed member and the fixing member.

  In this invention, a 1st annular body is interposed between the said fixing member and a to-be-fixed member, and the said 1st fitting part is the one end surface of the said 1st annular body, the said fixing member, or the said to-be-fixed member. The fastening unit includes a bolt and the second annular body, the second annular body is interposed between the fixed member and the head of the bolt, and the second A fitting portion is formed between one end surface of the second annular body and the fixed member or the bolt, and the first and second annular bodies are set to have a larger inner diameter than the shaft portion of the bolt. The other end surface is preferably formed as a flat surface orthogonal to the center line (C) of the fixing hole. According to this configuration, it is possible to absorb the axial displacement of the fixing member and the fixed member at the other end surface while absorbing the inclination of the fixing member and the fixing member at the one end surfaces of the first and second annular bodies.

  In the present invention, it is preferable that the first predetermined distance and the second predetermined distance are the same. According to this configuration, since the curvatures of the first annular body and the second annular body are the same, the first annular body and the second annular body can be shared, and the number of parts is reduced. be able to.

  In the present invention, the fixing hole of the fixing member is preferably a screw hole. According to this configuration, a nut is unnecessary, and the number of parts is reduced.

  In the present invention, the body frame is a body frame of a motorcycle that supports an engine, the fixing member is a main frame that is welded to a head pipe and extends rearward, and the fixed member is a side of the main frame. Preferably, the sub-frame is attached to the side and extends from the front side to the rear side of the engine. This subframe can prevent unexpected movement to the side of the engine.

  According to the fastening structure of the vehicle body frame of the present invention, the fixed member is pressed along the curved surface by the fastening unit head and the fixing member, so that the portion to be covered is equal to the gap between the shaft portion of the fastening unit and the fixing hole. Even if the fixing member is inclined with respect to the fixing member, it can be fastened. As a result, even if there is a dimensional error, assembly error, etc. between the fixed member and the fixed member and they are relatively inclined, they can be connected to each other in an inclined state, and undesired tightening stress is generated. Can be prevented.

1 is a side view showing a motorcycle including a body frame fastening structure according to a first embodiment of the present invention. It is a perspective view which shows the same vehicle body frame. (A) is a side view which shows the sub-frame which comprises some vehicle body frames, (b) is a top view, (c) is the IIIC-IIIC sectional view taken on the line of (a). It is a disassembled perspective view which shows the fastening structure. It is a longitudinal cross-sectional view which shows the fastening structure of the rear-end part of the sub-frame of FIG. FIG. 6 is a longitudinal sectional view showing an inclined state of a subframe, which is different from FIG. 5. It is a longitudinal cross-sectional view which shows the modification of the fastening structure. It is a longitudinal cross-sectional view which shows the fastening structure of the vehicle body frame which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the modification of the fastening structure. It is a longitudinal cross-sectional view which shows the fastening structure of the vehicle body frame which concerns on 3rd Embodiment of this invention. It is a longitudinal cross-sectional view which shows the modification of the fastening structure. It is a longitudinal cross-sectional view which shows the fastening structure of the vehicle body frame which concerns on 4th Embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
A motorcycle body frame FR shown in FIG. 1 includes a main frame 1 constituting a front half, a rear frame 2 connected to a rear part of the main frame 1 and constituting a rear half, and a pair of left and right frame brackets 8. The main frame 1 includes a pair of left and right subframes 10 extending from the front to the rear. A front fork 5 is supported by the head block 3 at the front end of the main frame 1, a front wheel 7 is supported at the lower end portion of the front fork 5, and a handle 9 is attached to the upper end portion. The main frame 1 is fixed to the head block 3 at the tip end by, for example, welding.

  As shown in FIG. 2, the main frame 1 is formed by connecting a pair of left and right main frame pieces 1a, 1a with a plurality of cross bars 1b. Each main frame 1 a is formed with swing arm brackets 11, 11 at rear end portions inclined downward and rearward, and the swing arm brackets 11, 11 have the front end portion of the swing arm 13 of FIG. It is supported freely. A rear wheel 17 is supported at the rear end of the swing arm 13. A rear suspension 19 is disposed between the main frame 1 and the swing arm 13. An engine E is mounted at a position below the central portion of the main frame 1, and the rear wheel 17 is driven by the engine E via a transmission member 21 such as a chain. The engine E is supported on the vehicle body frame FR by three engine support portions 12, 14, and 16.

  Each sub-frame 10 is connected to a frame bracket 8 that extends downward from the front portion of the main frame 1, and a front end portion 10 a is connected to the side of the engine E so as to extend from the front of the engine E to the rear thereof. It is connected to the rear part and reinforces the main frame 1 and at the same time has an engine support part 12 in the middle part in the front-rear direction. The sub-frame 10 prevents unexpected movement of the engine E to the side. Each subframe 10 and each swing arm bracket 11 are partially or entirely covered from the outside by resin covers 22 and 24, respectively.

  A fuel tank 23 is disposed on the upper part of the main frame 1, a resin front cowl 25 covering the front of the head block 3 is mounted in front of the fuel tank 23 at the front of the vehicle body, and a headlamp unit 27 is mounted on the front cowl 25. It is installed. A side cowl 29 that forms a windshield against the rider's legs is disposed in front of the engine E and supported by the main frame 1. A driver seat 31 and a passenger seat 33 are mounted on the upper portion of the rear frame 2, and both sides of the rear frame 2 are covered with a rear cover 35.

  The front part of the vehicle body frame FR with the covers 22 and 24 removed is shown in FIG. The main frame 1, the frame bracket 8, and the subframe 10 are, for example, steel castings. The frame bracket 8 has an upper end 8a connected to the front end 1aa of the main frame piece 1a. The subframe piece 10 extends rearward from the lower end portion 8 b of the frame bracket 8 and reaches the rear portion 1 ab of the main frame 1. The upper end portion 8a of the frame bracket 8 is overlapped with the outer surface of the front end portion 1aa of the main frame piece 1a that is outside the vehicle body, the front end portion 10a of the subframe 10 is overlapped with the outer surface of the lower end portion 8b of the frame bracket 8, and The rear end portion 10b of the frame 10 is overlapped with the outer surface of the rear portion 1ab of the main frame 1 and connected by bolts 100, 102, 64 inserted from the outside of the vehicle body.

  In other words, the sub-frame 10 is a fixed member fixed to the frame bracket 8 and the main frame 1 that are fixing members, has an elongated shape, and both end portions 10a and 10b in the longitudinal direction are separate members. In the embodiment, both ends are fixed to the lower end portion 8b of the frame bracket 8 and the rear portion 1ab of the main frame piece 1a.

  The connection between the front end 1aa of the main frame piece 1a and the upper end 8a of the frame bracket 8 is performed by inserting a bolt 100 having a male screw formed at the tip into a bolt insertion hole (not shown) provided in the frame bracket 8, This is done by tightening in a screw hole (not shown) provided in the main frame piece 1a. To connect the lower end portion 8b of the frame bracket 8 and the front end portion 10a of the subframe 10, the bolt 102 is inserted into the first bolt insertion hole 42 (FIG. 3A) provided in the subframe 10, and the frame bracket is inserted. This is done by tightening into a screw hole (not shown) provided in FIG. A fastening structure M of the present invention to be described later is used to connect the rear end portion 10b of the subframe 10 and the rear portion 1ab of the main frame piece 1a.

  As shown in FIGS. 3A and 3B, the sub-frame 10 has two first bolt insertion holes 42 formed in the front end portion 10a, which is one end portion in the longitudinal direction, and an intermediate portion in the longitudinal direction. Further, a boss portion 12 constituting one of the engine support portions is formed, and a second bolt insertion hole 12a is formed in the boss portion. Two fixed portions 44, 44 that are part of the fastening structure M of the present invention are provided at the rear end portion 10b of the subframe 10 so as to be bifurcated vertically.

  The fixed portion 44 is formed of a first spherical seat 46 having a curved surface 44a facing the vehicle body outside and smoothly curved toward the vehicle body inside, and a surface 44b facing the vehicle body inner side shown in FIG. It consists of a flat surface. Further, a fixed hole 48 including a through hole is formed in the fixed part 44.

  As shown in FIG. 4, the rear end portion 10 b of the subframe 10 is bolted to the intermediate member 50 that is a part of the main frame 1 via first and second annular bodies 60 and 62. The intermediate member 50 is a forged product made of steel, for example, and is fixed to the main frame 1 by welding. The outer surface of the intermediate member 50 protrudes slightly outside the vehicle body from the outer surface of the main frame 1, thereby preventing direct contact between the rear end portion 10 b of the subframe 10 and the main frame 1. The intermediate member 50 may be omitted.

  The intermediate member 50 has a long and narrow shape extending in the vertical direction, and fixed portions 52 and 52 that are part of the fastening structure M are formed at both upper and lower ends. The fixed portions 52 and 52 are respectively located at positions corresponding to the fixed portions 44 and 44 of the subframe 10, and a second spherical seat having a surface 52 a facing the outside of the vehicle body is a curved surface smoothly curved toward the inside of the vehicle body. 54. Further, a fixing hole 56 made of a screw hole is formed in the fixing portion 52.

  The first and second annular bodies 60 and 62 are, for example, steel washers. The first annular body 60 is interposed between the fixing portion 52 of the main frame 1 and the fixed portion 44 of the second frame piece 40. The 2nd annular body 62 is interposed between the to-be-fixed part 44 of the 2nd frame piece 40, and the head 64a of the volt | bolt 64 which is a kind of fastening member. The bolt 64 and the second annular body 62 constitute a fastening unit U. As will be described later, the second annular body 62 may be integrally formed with a head portion 64a of the bolt 64. The shaft portion 64 b of the bolt 64 is inserted through the through hole 62 a of the second annular body 62, the fixing hole 48 of the fixed portion 44, and the through hole 60 a of the first annular body 60 in this order. By screwing into the fixing hole 56, the second frame 62, that is, the head of the fastening unit U, presses the subframe 10 as the fixed member against the main frame 1 as the fixing member, The main frame 1 is fastened.

  As shown in FIG. 5, one end surface of the first annular body 60, in this embodiment, the inner end surface on the main frame 1 side has a shape that matches the second spherical seat 54 of the main frame 1. The convex surface 66 is provided. That is, the second spherical seat 54 of the main frame 1 and the first convex surface 66 of the first annular body 60 serve as the first contact surface and constitute the first fitting portion 68.

  The first contact surfaces 54 and 66 are arranged in one direction of the axis C from the intersection A1 between the virtual surface V1 extending from the first contact surfaces 54 and 66 toward the center and the axis C of the bolt 64, in this embodiment. Then, it consists of a spherical surface centered on the first center point A2 moved to the outer side P by the first predetermined distance L1. On the other hand, the outer end surface 69, which is the other end surface of the first annular body 60, is formed as a flat surface orthogonal to the axis C and is in contact with the inner side surface 44 b facing the inner side of the vehicle body in the fixed portion 44 of the subframe 10. Yes.

  One end surface of the second annular body 62, in this embodiment, the inner end surface on the subframe 10 side has a second convex surface 70 having a shape that matches the first spherical seat 46 of the subframe 10. Yes. That is, the first spherical seat 46 of the subframe 10 and the second convex surface 70 of the second annular body 62 serve as the second contact surface and constitute the second fitting portion 72.

  The second abutting surfaces 46 and 70 are outward from the intersection B1 between the virtual surface V2 obtained by extending the second abutting surfaces 46 and 70 toward the center and the axis C of the bolt 64, which is one direction of the axis C. And a spherical surface centered on the second center point B2 moved by the second predetermined distance L2. The outer end surface 71, which is the other end surface of the second annular body 62, is formed as a flat surface orthogonal to the axial center C, and is in contact with the neck lower surface 64 aa of the bolt head portion 64 a that is a flat surface orthogonal to the axial center C. It touches. In the present embodiment, the first predetermined distance L1 and the second predetermined distance L2 are set to be the same. That is, the first and second contact surfaces are spherical and have the same curvature. Such first and second convex surfaces 66 and 70 having curved surfaces can be obtained by pressing the first and second annular bodies 60 and 62.

  The inner diameter d2 of the fixed hole 48 is set to be smaller than the diameter d1 of the second annular body 62 included in the head of the bolt unit U and larger than the diameter D2 of the shaft portion 64b. The diameter D1 of the head 64a of the bolt 64 is also set larger than the diameter d1 of the second annular body 62. Accordingly, the tightening force of the bolt 64 by the head portion 64 a acts on the subframe 10 straight along the axis C via the second annular body 62, so that it is excessive on the inner peripheral portion of the second annular body 62. Bending stress does not occur.

  The inner diameters d3 and d4 of the through holes 60a and 62a of the first and second annular bodies 60 and 62 are also smaller than the diameter D1 of the head portion 64a of the bolt 64 and larger than the diameter D2 of the maximum diameter portion of the shaft portion 64b. It is set large.

  Next, a method of attaching the engine E and the sub frame 10 of FIG. 1 to the main frame 1 will be described. First, the engine E is fixed to the two engine support portions 14 and 16 of the main frame 1 using bolts (not shown). Next, the upper end portion 8a of the frame bracket 8 is fixed to the front portion 1aa of the main frame piece 1a using the bolt 100 of FIG. Subsequently, the rear end portion 10b of the sub-frame 10 is loosely temporarily fixed to the rear portion 1ab of the main frame piece 1a by the bolt 64. Next, the lower end portion 8 b of the frame bracket 8 and the front end portion 10 a of the subframe 10 are connected using the bolt 102. Further, the rear bolt 64 is strongly tightened to fix the rear end portion 10b of the subframe 10 to the rear portion 1ab of the main frame piece 1a. Finally, the engine E (FIG. 1) is fixed to the engine support part 12 of the subframe 10 using a bolt (not shown).

  In the above configuration, since there are dimensional errors, assembly errors, and the like between the main frame 1 and the subframe 10, the shaft 64 b of the bolt 64 and the subframe 10 are fixed as shown in FIG. 6. The subframe 10 may be inclined with respect to the main frame 1 by the gap between the main hole 1 and the main frame 1 and the subframe 10 are bolted by the first fitting portion 68 that is a spherical seat. The second annular body 62 of the bolt unit U and the subframe 10 are also in contact with each other in the direction of the axis C of the bolt 64 without any gap. Thereby, even if the sub frame 10 is tilted with respect to the main frame 1, it is possible to prevent an undesired tightening stress from being generated.

  As shown in FIG. 2, the subframe 10 that is a member to be fixed has an elongated shape, and the fastening structure M is used only at one end portion 10 b of the both end portions 10 a and 10 b in the longitudinal direction. Therefore, by allowing the error at the one end (rear end) 10b and bearing the strength at the other end (front end) 10a, it is possible to achieve both high strength and dimensional error tolerance.

  Further, as shown in FIG. 5, since the first and second fitting portions 68 and 72 are spherical, the multi-directional inclination between the main frame 1 and the sub frame 10 can be effectively absorbed.

  The first and second annular bodies 60 and 62 have inner diameters d3 and d4 larger than the shaft portion 64b of the bolt 64, and the other end surfaces 69 and 71, which are end surfaces opposite to the contact surfaces 66 and 70, are axial lines. Since the first and second annular bodies 60 and 62 are absorbed by the end faces 66 and 70 of the first and second annular bodies 60 and 62 while absorbing the inclination of the main frame 1 and the subframe 10, 71 can absorb the misalignment between the main frame 1 and the subframe 10. That is, the subframe 10 and the first annular body 60 are in contact with each other on a flat surface, and the subframe 10 and the head 64a of the bolt 64 are in contact with each other on a flat surface via the second annular body 62. The sub-frame 10 is not restrained from moving in the direction orthogonal to the axis C of the bolt 64 with respect to the main frame 1. Therefore, since the parallel movement (axial deviation) between the main frame 1 and the sub frame 10 due to thermal deformation caused by the heat of the engine E or the like can be absorbed, generation of a large thermal stress can be suppressed.

  Further, since the first predetermined distance L1 and the second predetermined distance L2 are the same, the curvatures of the first annular body 60 and the second annular body 62 are the same, and the first annular body 60 and the second annular body 60 are the same. The annular body 62 can be made a common part, and the number of parts is reduced.

  Further, since the fixing hole 56 of the main frame 1 is constituted by a screw hole, a nut is not necessary, the number of parts is reduced, and the amount of protrusion of the shaft portion 64b of the bolt 64 inward in the vehicle width direction is reduced. Less.

  As shown in FIG. 2, the intermediate member 50 is formed so as to protrude outward in the vehicle width direction from the main frame 1, so that even if the subframe 10 is attached to the main frame 1 at an angle, the main frame 1 Can be prevented from interfering with. 4 is formed in the vicinity of the edge of the subframe 10, specifically, the front edge, so that even if the subframe 10 is largely inclined with respect to the main frame 1, the subframe The tip of 10 can be prevented from contacting the intermediate member 50.

  In the present embodiment, both end portions 10 a and 10 b of the subframe 10 shown in FIG. 2 are fixed to the main frame 1 at positions shifted in the vehicle width direction that is the axial center direction of the bolt 64. The main frame 1 to which both end portions 10a and 10b of the subframe 10 are fixed is not a single molded member but an assembly structure in which other members are welded or bolted to a single molded member. In such a case, there is a high possibility that the sub-frame 10 is inclined and attached due to a dimensional error, an attachment error, or the like, and therefore it is particularly effective to apply the fastening structure M of the present invention.

  FIG. 7 is a cross-sectional view showing a modification of the fastening structure according to the first embodiment. In this example, the first spherical seat 46A of the subframe 10 and the second spherical seat 54A of the main frame 1 are formed of curved surfaces that bulge outward. The first and second spherical seats 46A and 54A have shapes obtained by inverting the first and second spherical seats 46 and 54 of FIG. 5 by 180 °, respectively. The surface in contact with the main frame 1 in the first annular body 60 is configured by a first concave surface 74 that matches the shape of the second spherical seat 54A, and the surface in contact with the subframe 10 in the second annular body 62 is The second concave surface 76 conforms to the shape of the first spherical seat 46A.

  That is, the second spherical seat 54A of the main frame 1 and the first concave surface 74 of the first annular body 60 serve as a first contact surface to form the first fitting portion 68, and the subframe 10 The first spherical seat 46 </ b> A and the second concave surface 76 of the second annular body 62 serve as a second contact surface and constitute a second fitting portion 72. The first and second abutment surfaces are spherical and have the same curvature. The rest of the configuration is the same as that of the example of FIG. 5, and the modified example of FIG. 7 also has the same effect as the example of FIG.

  FIG. 8 is a cross-sectional view showing a fastening structure according to the second embodiment. In the second embodiment, the contact surface between the main frame 1 and the first annular body 60 is formed as a flat surface orthogonal to the axis C of the bolt 64, and the vehicle body inner side in the fixed portion 44 of the subframe 10. The second spherical seat 78 is formed with a curved surface 44b facing outward. The surface of the first annular body 60 that comes into contact with the sub-frame 10 is constituted by a first convex surface 80 that matches the shape of the second spherical seat 78. That is, the main frame 1 has no spherical seat.

  That is, the second spherical seat 78 of the subframe 10 and the first convex surface 80 of the first annular body 60 serve as a first contact surface and constitute the first fitting portion 68. The first contact surface has a spherical shape, and the curvature thereof is the same as that of the second contact surface. The other configuration is the same as the modification of the first embodiment in FIG. In the second embodiment, the same effects as in the first embodiment are obtained. Further, in the second embodiment, since the spherical seat is not formed on the main frame 1, the large main frame 1 can be easily manufactured.

  FIG. 9 is a cross-sectional view showing a modification of the fastening structure according to the second embodiment. In this example, the first spherical seat 46 of the sub-frame 10 is formed with a curved surface recessed inward, and the second spherical seat 82 is formed with a curved surface bulging inward, and the first annular body 60 is formed. The surface in contact with the sub-frame 10 is composed of a first concave surface 84 that matches the shape of the second spherical seat 82. The surface of the second annular body 62 that comes into contact with the subframe 10 is constituted by a second convex surface 70 that matches the shape of the first spherical seat 46.

  That is, the second spherical seat 82 of the subframe 10 and the first concave surface 84 of the first annular body 60 serve as a first contact surface to form the first fitting portion 68, and the first spherical seat 46 and the first convex surface 70 of the first annular body 60 serve as a second abutting surface and constitute a second fitting portion 72. The first and second abutment surfaces are spherical and have the same curvature. The other configuration is the same as that of the example of FIG. 8, and the modification of FIG. 9 has the same effect as the example of FIG.

  FIG. 10 is a cross-sectional view showing a fastening structure according to the third embodiment. In the third embodiment, the first annular body is omitted. In the third embodiment, a second spherical seat 54 having a curved surface recessed inward is formed in the main frame 1, and a surface 44 a facing the vehicle body and a surface 44 b facing the inside of the fixed portion 44 of the subframe 10 are formed. The first spherical seat 46 and the second spherical seat 82 are formed by curved surfaces that bulge inward. The bolt unit U <b> 1 is a hooked bolt, and the surface of the flange 86 of the bolt 64 </ b> A that contacts the subframe 10 has a curved surface 88 that is a curved surface that matches the first spherical seat 46. That is, the bolt unit U1 is obtained by integrating the bolt 64 and the second annular body 62 in the first embodiment.

  The second spherical seat 82 of the subframe 10 and the second spherical seat 54 of the main frame 1 serve as a first contact surface to form a first fitting portion 68, and the first spherical seat of the subframe 10. 46 and the curved surface 88 of the collar portion 86 of the bolt 64 </ b> A serve as a second contact surface to constitute the second fitting portion 72. The first and second abutment surfaces are spherical and have the same curvature. Other configurations are the same as those of the first and second embodiments.

  Also in the third embodiment, the inclination of the mounting surfaces of the main frame 1 and the subframe 10 can be absorbed, as in the first and second embodiments. In the third embodiment, the sub-frame 10 and the main frame 1 are in direct contact with each other via the second spherical seat 82, and the bolt unit U1 having the flange portion 86 is in direct contact with each other through the second fitting portion 72. Therefore, the sub frame 10 cannot move in the direction perpendicular to the axis C of the bolt 46 </ b> A with respect to the main frame 1. Therefore, the effect of absorbing the axial displacement between the subframe 10 and the main frame 1 as in the first and second embodiments is not achieved, but the first annular body is omitted and the second annular body 62 is replaced with a bolt unit. Since it is integrally formed with U1, the number of parts can be reduced.

  FIG. 11 is a cross-sectional view illustrating a modification of the fastening structure according to the third embodiment. In this example, the second spherical seat 54A of the main frame 1 is formed with a curved surface that bulges outward, and the second spherical seat 78 of the subframe 10 matches the second spherical seat 54A of the main frame 1. The first spherical seat 46A of the subframe 10 is formed with a curved surface that bulges outward, and the curved surface 88 of the flange 86 of the bolt 64A is a curved surface that matches the shape of the first spherical seat 46A. It consists of Other structures are the same as those of the third embodiment shown in FIG. Also in this modification, the same effects as those of the third embodiment shown in FIG. 10 are obtained.

  FIG. 12 is a cross-sectional view showing a fastening structure according to the fourth embodiment. In the fourth embodiment shown in FIG. 10, the fixing hole 56 formed of a screw hole of the main frame 1 is used as a fixing hole 56 </ b> A formed of a through hole, and a bolt 64 A is tightened by a nut 90. The other configuration is the same as that of the third embodiment in FIG. According to the fourth embodiment, the number of parts is increased as compared with the third embodiment, but tapping processing is not required for the main frame 1. In the fourth embodiment, the nut 90 is provided in the third embodiment of FIG. 10, but also in the embodiments of FIGS. 5 to 9 and 12, the screw hole of the main frame 1 is replaced with a through hole and the nut 90 is provided. You can

  Moreover, in each said embodiment, although the fastening structure M of this invention is used only for one edge part 10b of the sub-frame 10, you may provide in both edge part 10a, 10b. Furthermore, for example, the fastening structure of FIG. 5 can be adopted at one end 10b of the subframe 10, and the fastening structure of FIG. 10 can be adopted at the other end 10a. Thereby, the inclination of an attachment surface is accept | permitted by the fastening structure of both ends 10a and 10b, and inclination and an axial shift can be accept | permitted by the fastening structure of one edge part 10b. Besides this, it is possible to arbitrarily combine the fastening structures of FIGS.

  Furthermore, when the inclination direction of the subframe 10 with respect to the main frame 1 is limited to one plane, the first and second fitting portions 68 and 72 may be formed by a part of a cylindrical surface instead of a spherical surface. it can. In that case, since the direction in which the subframe 10 is inclined is included in a plane orthogonal to the line L1 connecting the axes of the two bolts 64 and 64 in the example of FIG. 2, the axis parallel to the straight line L1. A part of a cylindrical surface having a heart is used.

  Alternatively, the frame bracket 8 may be integrally formed with the subframe 10 to form an L-shaped subframe 10. Furthermore, although each said embodiment demonstrated the case where the to-be-fixed member was the sub-frame 10, it is applicable to the whole fastening structure of the two members which comprise the vehicle body frame FR. In particular, in the case of an elongated member that is fastened to both ends of the fixed member, if the mounting surfaces at both ends are displaced in the fastening direction, the mounting surface is likely to be tilted. The fastening structure of the invention is preferably applied. The fastening unit U may have a separate head and shaft. That is, a structure in which nuts are screwed to both ends of a long screw bolt that is a shaft portion may be employed.

  Moreover, although the structure connected with a volt | bolt as a fastening unit was demonstrated, it is not limited to this, For example, you may press-fix a fixing member and a to-be-fixed member. Examples of pressing and fixing include a wedge structure or a holding structure that uses the elastic force of a material by sandwiching a fixing member and a fixed member between U-shaped members.

  Further, even when the two annular bodies 60 and 62 are not used, when the first and second contact surfaces 46 and 54 are cut, the first predetermined distance L1 and the second predetermined distance L2 are set to be the same. Thereby, the processing process of each contact surface 46 and 54 can be made common. Further, the first predetermined distance L1 and the second predetermined distance L2 may be different. Accordingly, the curvatures of the two contact surfaces 46 and 54 are different, and an allowable mounting error can be increased. For example, the first center point A2 in FIG. 5 is moved upward to coincide with the second center point B2, thereby making the second predetermined distance L2 longer than the first predetermined distance L1 and the first contact surface. The curvature of 54 is made larger than the curvature of the second contact surface 46. Thereby, a larger inclination of the subframe 10 with respect to the main frame 1 can be allowed.

  The present invention is not limited to the contents shown in the above embodiments, and various additions, modifications, or deletions can be made without departing from the spirit of the present invention. It is included in the range.

1 Main frame (fixing member)
10 Subframe (fixed member)
46, 46A First spherical seat (second contact surface)
48 Fixed holes 54, 54A, 78, 82 Second spherical seat (first contact surface)
56 fixing hole 60 first annular body 62 second annular body 64, 64A fastening member (bolt)
64a Head 64b Shaft portions 66, 80 First convex surface (first contact surface)
68 1st fitting part 70 2nd convex surface (2nd contact surface)
72 2nd fitting part 74,84 1st concave surface (1st contact surface)
76 Second concave surface (second contact surface)
88,88A Curved surface (second contact surface)
FR body frame U, U1 fastening unit

Claims (7)

A fixed member that constitutes a part of the body frame and has a fixed hole formed of a through hole;
A fixing member that constitutes another part of the vehicle body frame and has a fixing hole for fixing the fixed member;
A fastening unit having a shaft portion having a smaller diameter than the fixed hole and a head portion having a larger diameter than the fixed hole;
The fastening unit is inserted on the fixing hole through the shaft portion and fastened on the fixing member side, so that the fixing member is pressed against the fixing member by the head portion and the fixing member and the fixing member. Fasten the fixing member,
The first contact surface between the fixed member and the fixed member is a center line (C1) from the intersection (A1) between the virtual surface on each first contact surface and the center line (C) of the fixing hole. ) Constitutes a first fitting portion that curves along a first curved surface with the first center point (A2) moved in the first direction by a first predetermined distance (L1) as the center of curvature,
The second contact surface between the fixed member and the fastening unit head is a center line from the intersection (B1) between the virtual surface on each second contact surface and the center line (C) of the fixing hole. (C) The vehicle body frame constituting the second fitting portion that curves along the second curved surface with the second center point (B2) moved in the one direction as the second predetermined distance (L2) as the center of curvature. Fastening structure.   2. The fixed member according to claim 1, wherein the fixed member has an elongated shape, and both end portions in the longitudinal direction are fixed to separate members, and the fastening structure is provided only at one end portion of the both end portions. Fastening structure of the body frame used.   The fastening structure for a vehicle body frame according to claim 1 or 2, wherein the first and second curved surfaces are spherical. In Claim 1, 2, or 3, a 1st annular body is interposed between the fixing member and a member to be fixed, and the 1st fitting part is the end face of the 1st annular body, the fixing member, or Formed between the fixed member,
The fastening unit has a bolt and the second annular body,
The second annular body is interposed between the fixed member and the head of the bolt, and the second fitting portion is formed between one end surface of the second annular body and the fixed member or the bolt. Formed between,
The first and second annular bodies have an inner diameter larger than that of the shaft portion of the bolt, and the other end surface of the body frame is formed as a flat surface perpendicular to the center line (C) of the fixing hole. Fastening structure.   The fastening structure for a vehicle body frame according to any one of claims 1 to 4, wherein the first predetermined distance and the second predetermined distance are the same.   The fastening structure for a vehicle body frame according to any one of claims 1 to 5, wherein the fixing hole of the fixing member is a screw hole. The vehicle body frame according to any one of claims 1 to 6, wherein the body frame is a body frame of a motorcycle that supports an engine.
The fixing member is a main frame that is welded to the head pipe and extends rearward.
The fastening member is a fastening structure of a vehicle body frame that is a sub-frame that is attached to a side of the main frame and extends from the front to the rear on the side of the engine.

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