JP2716053B2 - Method and apparatus for attaching bracket to motorcycle frame - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for attaching a bracket for mounting an exterior member such as a cowl and a side cover to a motorcycle frame, and more particularly to a motorcycle. The present invention relates to a method and an apparatus for mounting a bracket for a motorcycle frame, in which after a frame for use is assembled, a pivot portion and a head pipe portion of the frame are positioned, and a bracket is mounted on the frame based on the pivot portion. [Background of the Invention] In general, in a motorcycle, an engine, a carburetor, and the like are incorporated in a body frame, and a cowl, a side cover, or the like is provided on an outer peripheral portion thereof to reduce wind resistance or to make the appearance beautiful. An exterior member is mounted. In this case, the exterior member is mounted via a bracket attached to a predetermined portion of the vehicle body frame. By the way, a body frame is mainly composed of an upper frame formed by joining a main pipe to a head pipe, a lower frame formed by joining a down tube and a cross pipe, and a rear frame joined to the upper frame and the lower frame. . In this case, a bracket for mounting an exterior member such as a cowl or a side cover is conventionally individually attached to each frame pipe before assembly by welding or the like based on design dimensions (see Japanese Utility Model Application Publication No. 59-55290). No.). However, when the brackets are attached in this manner, there is a possibility that an error may occur in the mounting attitude of the mutually related brackets due to the influence of welding distortion generated when each bracket is attached. In addition, when the frames with the brackets attached thereto are joined by welding and assembled, the influence of welding distortion also occurs. For example, there is a disadvantage that the relative positional relationship between the brackets attached to each frame causes an error. It is pointed out. As described above, when an error occurs in the mounting position of the bracket, not only is it extremely difficult to mount an exterior member such as a cowl or a side cover to the frame,
This causes a disadvantage that the exterior member is deformed to deteriorate the appearance and to be easily damaged. [Object of the Invention] The present invention has been made in order to overcome the above-described disadvantages. After assembling a body frame of a motorcycle, a pivot portion and a head pipe portion of the body frame are positioned, and the pivot portion is By mounting the bracket on the basis of the design dimension value as a reference, the positioning accuracy of the bracket with respect to the vehicle body frame is improved, the mounting of the exterior member on the bracket is facilitated, and the appearance of the vehicle body by the mounted exterior member is extremely good. It is an object of the present invention to provide a bracket mounting method and mounting of a motorcycle frame to be used. Means for Achieving the Object In order to achieve the above object, the present invention relates to a bracket mounting method for mounting an exterior member on a motorcycle frame, wherein the jig is assembled after the motorcycle frame is assembled. On the above, the positioning of the pivot portion and the head pipe portion of the motorcycle frame with respect to the jig is corrected, and further,
A plurality of brackets are positioned with respect to the motorcycle frame in a mutual positional relationship based on a design dimension value of the exterior member, with respect to the pivot portion, and then, using a joining means, to position the bracket with respect to the motorcycle frame. It is characterized in that each bracket is attached. In addition, the present invention provides a pivot clamp mechanism that corrects the positioning of the pivot portion of the motorcycle frame with respect to the jig, a head pipe clamp mechanism that corrects the positioning of the head pipe portion of the motorcycle frame with respect to the jig, and the motorcycle. A plurality of bracket clamp mechanisms for holding a bracket for mounting an exterior member attached to the frame in a predetermined posture, wherein each of the bracket clamp mechanisms is based on the pivot portion, A first and a second, which are arranged in a mutual positional relationship based on the design dimension value and are provided opposite to both side portions of the motorcycle frame so as to be able to move closer to the motorcycle frame under the action of the driving means. When the first and second side bases move close to each other, the pivot The first and second side bases are stopped at predetermined positions based on the design dimensions of the exterior member of the motorcycle frame with respect to the part, and the positioning of each bracket clamp mechanism with respect to the motorcycle frame is performed. And positioning means for performing. [Embodiment] Next, a preferred embodiment of a bracket mounting method for a motorcycle frame according to the present invention will be described in detail with reference to the accompanying drawings, in relation to a device for performing the method. In FIG. 1, reference numeral 10 denotes a body frame of a motorcycle to which a bracket is mounted by the bracket mounting device according to the present embodiment. The body frame 10 includes an upper frame, a lower frame, and a rear frame. The upper frame includes a head pipe 14 having a front fork insertion hole 12, and main pipes 16a and 16b having one ends joined to the head pipe 14. The lower frame includes down tubes 18a and 18b having upper ends joined to one ends of the main pipes 16a and 16b, and down tubes 20a and 20b having one ends joined to lower ends of the down tubes 18a and 18b.
And The upper ends of the pivot plates 24a and 24b having the swing arm mounting holes 22a and 22b are connected to the other ends of the main pipes 16a and 16b constituting the upper frame. The rear frame is the main pipe 16
a, 16b seat rail pipe 26a joined to the other end side
And a rear sub tube connecting the seat rail pipes 26a and 26b and the other ends of the down tubes 20a and 20b.
28a and 28b. The lower portions of the pivot plates 24a, 24b are connected to the rear sub tubes 28a, 28b. Between the main pipes 16a and 16b, cross pipes 30a and 30b and a cross plate 32a for reinforcing between both end portions and an intermediate portion are bridged. Also, down tubes 18a, 18b
Cross pipes 30c to 30e for reinforcement are also bridged between the spaces, between 20a and 20b, and between the rear sub tubes 28a and 28b, respectively. Further, a cross plate 32b and a cross pipe 30f are similarly bridged between the seat rail pipes 26a and 26b. Here, head pipe 14, main pipe 16a, 16b, down tube 18a, 18b, 20a, 20b, seat rail pipe
Predetermined brackets 34a to 34q for mounting exterior members such as cowls and side covers are attached to predetermined portions of 26a, 26b and rear sub tubes 28a, 28b by the bracket mounting device according to the present embodiment. Each bracket 34
a to 34q have holes 35a to 35q for mounting exterior members.
Are formed. Next, the configuration of the bracket mounting device according to the present embodiment will be described with reference to FIGS. Therefore, in FIG. 2, reference numeral 40 indicates a main body of the bracket mounting device. This body 40 is a base plate
A pivot clamp mechanism 44 arranged substantially at the center of 42,
A head pipe clamp mechanism 46 disposed in front of the base plate 42, and side bases 48A and 48B disposed on both sides of the base plate 42 and capable of approaching or separating from each other.
It is basically composed of In this case, the pivot clamp mechanism 44 positions the vehicle body frame 10 by engaging with the swing arm mounting holes 22a and 22b formed in the pivot plates 24a and 24b. Further, the head pipe clamp mechanism 46 positions the vehicle body frame 10 by engaging with the front fork insertion hole 12 formed in the head pipe 14. In addition, side bases 48A and 48B
a ~ 34h and 34i ~ 34q are clamped to the body frame
Bracket clamp mechanism 50a to be set at a predetermined position of 10
~ 50h and 50i ~ 50q. The pivot clamp mechanism 44 is configured as shown in FIG. 3 and FIG. That is, a plate member 60 that stands parallel to the longitudinal direction (vehicle length direction) of the base plate 42 is erected at the center of the base plate 42, and two guide bars 62 a that are parallel to each other and are orthogonal to the plate member 60. And 62b are inserted. Both ends of the guide bars 62a and 62b are supported by support plates 64a and 64b erected on both sides of the base plate. A movable member 66a is engaged between the plate member 60 and the support plate 64a so as to be slidable with respect to the guide bars 62a and 62b, and the movable member 66a supports the support plate 68a.
A locate pin 70a that engages with the swing arm mounting hole 22a of the vehicle body frame 10 is attached through the hole. Similarly, plate 6
A movable member 66b is engaged between the support plate 64b and the support plate 64b, and a locate pin 70b that engages with the swing arm mounting hole 22b of the vehicle body frame 10 is attached to the movable member 66b via the support plate 68b. . In this case, a stopper 74 and an end stopper 76 for positioning the locate pin 70b with respect to the plate member 60 are attached to the opposing portions of the plate member 60 and the movable member 66b, respectively. On the other hand, cylinders 78a and 78b
One end of each of the cylinders 80a, 80b protruding from the other end of these cylinders 78a, 78b is connected to a connecting plate 82.
The movable members 66a and 66b are connected via a and 82b. Accordingly, the movable members 66a and 66b can be displaced in the direction of the arrow along the guide bars 62a and 62b under the driving action of the cylinders 78a and 78b. As shown in FIG. 3, the head pipe clamp mechanism 46 is supported via a support column 90 that is erected at the front center of the base plate 42 in a slightly inclined state. A front fork insertion hole in the head pipe 14 is provided at the upper end of the support column 90.
A lower clamp member 94 that engages the lower end of 12 is attached,
A cylinder 96 is mounted on the lower clamp member 94.
The other end of the upper clamp member 100 whose one end is engaged with the upper end of the front fork insertion hole 12 is axially attached to the tip of the cylinder rod 98 protruding from the cylinder 96. The middle part of the upper clamp member 100 is the lower clamp member 9
It is axially attached to the tip of the connecting plate 104 attached to 4. Side base 48A and 48B are bracket clamp mechanism
It has frames 106 and 108 that support 50a-50h and 50i-50q (see FIG. 2). These frames 10
6, 108 are pillars 110a, 110b and 112a, 112b standing upright at the front and rear of the base plate 42, and a horizontal member 114a extending from the middle of the pillars 110a, 110b toward the rear of the base plate 42. , 114b and horizontal members 118a, 118b further extending to the rear of the base plate 42 via the connecting members 116a, 116b and connected to the upper ends of the pillars 112a, 112b. In this case, side bases 48A and 48B are frame 10
Between pillars 110a, 110b and 112a, 11 constituting 6 and 108
Under the action of side base drive mechanisms 122 and 124 provided between 2b, they can be approached or separated from each other. Here, the side base drive mechanism 122 is configured as shown in FIG. That is, guide bars 126a and 126b extending toward the opposite frames 106 and 108 are implanted at lower ends of the pillars 110a and 110b constituting the frames 106 and 108, respectively. Is slidably fitted to guide members 130a and 130b mounted on the base plate 42. A cylinder 134 having one end attached to the pillar 110a is disposed above the guide bars 126a and 126b, and a cylinder rod 138 projecting from the other end of the cylinder 134 is engaged with the pillar 110b. Combine. On the other hand, since the side base drive mechanism 124 has the same configuration as the side base drive mechanism 122, the same reference numerals are given to the components, and the description of the configuration will be omitted. As a result, the side bases 48A and 48B can be moved closer to or away from each other under the driving action of the cylinder 134 forming the side base driving mechanisms 122 and 124. A rod-shaped side base stopper 144 supported by the support column 90 via the connecting plate 142 enters between the leg columns 110a and 110b. Also, the pillars 110a and 110b have recesses 146a and 146 formed at both ends of the side base stopper 144, respectively.
Stoppers 148a and 148b engaging with 46b are attached.
Similarly, as shown in FIG. 2 and FIG.
A rod-shaped side base stopper 15 attached to the upper end of a column 150 erected on the base plate 42 between 112b.
2 enters. In this case, recesses 154 formed at both ends of the side base stopper 152 are provided in the pillars 112a and 112b.
Stoppers 156a and 156b engaging with a and 154b are attached. Accordingly, the side bases 48A and 48B are positioned by the side base stoppers 144 and 152 when approaching. On the other hand, in FIG. 2 and FIG.
Bracket clamp mechanisms 50a to 50q for positioning the brackets 34a to 34q with respect to the vehicle body frame 10 are attached to predetermined portions of the frames 106 and 108 constituting A and 48B. Bracket clamp mechanisms 50a, 50b and 50j for positioning the brackets 34a, 34b and 34j are mounted on the upper ends of the pillars 110a and 110b in the frames 106 and 108. In this case, the bracket clamp mechanisms 50a and 50b
Are integrally formed as shown in FIG. That is, the bracket clamp mechanism 50a is connected to the cylinder 1 attached to the upper end of the pillar 110a via the mounting plates 158, 159 and 160.
62, a first clamp member 166 connected to the distal ends of the mounting plates 164a, 164b attached to the mounting plate 160, and a cylinder 162.
The connecting plate 169 is attached to the tip of the cylinder rod 168
a, 169b, and a second clamp member 170, one end of which is axially attached and the central part of which is axially attached to the mounting plates 164a, 164b. In this case, the first clamp member
166 has a locate pin (not shown) that engages with the hole 35a formed in the bracket 34a.
The other end of the clamp member 170 clamps the bracket 34a. The bracket clamp mechanism 50b includes a cylinder 174, a first clamp member 178 that is pivotally mounted on a distal end of a cylinder rod 176 protruding from the cylinder 174, and a hole formed in the bracket 174 with one end pivotally mounted on the cylinder 174 and the other end. It basically comprises a second clamp member 182 having a not-shown locating pin that engages with 35b. In this case, the first clamp member 17
8 and the second clamp member 182 are pivotally mounted on connecting plates 184a and 184b each having a central portion attached to the mounting plate 158.
4b is clamped. The bracket clamp mechanism 50j attached to the upper end of the pillar 110b has the same configuration as the bracket clamp mechanism 50b described above, and a description thereof will be omitted. Bracket clamp mechanisms 50c to 50e and 50k for positioning the brackets 34c to 34e and 34k to 34m at predetermined positions of the horizontal members 114a and 114b of the frames 106 and 108.
~ 50m is installed. In this case, the bracket clamp mechanism 50c is configured as shown in FIG. That is,
The bracket clamp mechanism 50c is attached to the mounting member 192 on the horizontal member 114a.
Cylinder 196 mounted via
4, a first clamp member 200 attached to the
The connecting plates 203a and 203b are attached to the tip of a cylinder rod 202 which is axially attached to the clamp member 200 and one end of which protrudes from the cylinder 196.
And a second clamp member 204 that is axially mounted via the second clamp member 204. In this case, the first clamp member 200 has a locate pin (not shown) that engages with the hole 35c of the bracket 34c.
Bracket 34c is clamped by the other end of the bracket 34c.
Note that the bracket clamp mechanisms 50d, 50e and 50k to 5k
Since 0m is a mechanism substantially similar to the bracket clamp mechanism 50c, the description of the configuration is omitted. On the other hand, connecting members 116 constituting frames 106 and 108
Bracket clamp mechanisms 50f to 50h and 50n to 50p, which are similar to the above-described bracket clamp mechanism 50c, are mounted on the a, 116b, the horizontal members 118a, 118b, and the pillars 112a, 112b. These bracket clamp mechanisms 5
0f to 50h and 50n to 50p clamp the brackets 34f to 34h and 34n to 34p to perform positioning with respect to a predetermined portion of the vehicle body frame 10. Bracket clamp mechanisms 50i and 50q for positioning the brackets 34i and 34q via mounting plates 220 are further mounted on the upper ends of the pillars 112a and 112b constituting the frames 106 and 108. In this case, the bracket clamp mechanism 50i is configured as shown in FIG. 9 and FIG. That is, the bracket clamp mechanism 50i is
Advancing / retracting cylinder 222 attached to mounting plates 221 and 223 through a cylinder rod 22 projecting from cylinder 222
4, a connecting plate 226 having a central portion attached thereto.
One end of each of guide bars 228a and 228b is attached to both ends of 226. The other ends of the guide bars 228a and 228b are connected to the guide members 230a and 230a attached to the mounting plate 223.
Slidably fits with 30b. A first clamp member 232 is attached to the connection plate 226 to which the guide bar 228b is attached, and a cylinder 234 for clamping is fixed to one end of the first clamp member 232. In this case, the first clamp member 232
At the other end, two locate pins 238a and 238b that engage with the two holes 35i of the bracket 34i are implanted. Further, a center portion of the second clamp member 244 is axially attached to a distal end portion of the cylinder rod 240 protruding from the cylinder 234 via a connecting plate 242. In this case, one end of the second clamp member 244 is axially attached to the center of the first clamp member 232, and the bracket 34i is clamped by the other end and the locate pins 238a and 238b. The bracket mounting device according to the present embodiment is basically configured as described above. Next, the operation and effect and the mounting method will be described. Here, a predetermined bracket 34 is attached to the bracket clamp mechanisms 50a to 50q attached to the side bases 48A and 48B.
a to 34q are clamped. That is, in FIGS. 6 and 7, the hole 35a of the bracket 34a is engaged with a not-shown locate pin of the first clamp member 166 constituting the bracket clamp mechanism 50a. When the second clamp member 170 is displaced in the direction of arrow A under the driving action of the cylinder 162, the bracket 34a is moved to the first and second positions.
It is clamped between the clamp members 166 and 170. Also, the second clamp member 182 constituting the bracket clamp mechanism 50b
The hole 35b of the bracket 34b is engaged with a locate pin (not shown), and the bracket 34b is clamped by the first clamp member 178 and the second clamp member 182 which are displaced in the direction of arrow B under the driving action of the cylinder 174. You. Further, the bracket clamp mechanism 50j is connected to the bracket clamp mechanism 50b.
Clamp the bracket 34j in the same manner as described above. The brackets 34c to 34h and 34k to 34p are clamped by predetermined bracket clamp mechanisms 50c to 50h and 50k to 50p, respectively. For example, in FIG. 8, a locating pin (not shown) of the first clamp member 200 is engaged with the hole 35c of the bracket 34c,
0 and the second clamp member 204 which is displaced in the direction of arrow C under the driving action of the cylinder 196. Further, the brackets 34i and 34q are clamped by the bracket clamp mechanisms 50i and 50q. That is, in FIG. 9 and FIG.
One of the holes 35i has the locate pin 23 of the first clamp member 232
8a and 238b are engaged, and the bracket 34i is clamped by the first clamp member 232 and the second clamp member 244 which is displaced in the direction of arrow D by the driving action of the cylinder 234. Similarly, the bracket 34q is connected to the bracket clamp mechanism 5
It is clamped by a bracket clamp mechanism 50q having the same configuration as 0i. Therefore, first, the head pipe 14, the main pipe 16a, 1
6b, pivot plates 24a, 24b, seat rail pipes 26
a, 26b and the rear sub tubes 28a, 28b are joined by welding or the like to assemble the vehicle body frame 10 (see FIG. 1). Next, the assembled vehicle body frame 10 is mounted on the main body 40 of the bracket mounting device shown in FIG. 2 for positioning. In this case, first, the swing arm mounting holes 22a and 22b are positioned using the pivot clamp mechanism 44. That is, in FIG. 3 and FIG.
When a and 78b are driven, the cylinder rods 80a and 80b are displaced, and the movable members 66a and 66b are moved through the connecting plates 82a and 82b.
Displaced in the directions of arrows E and F along 62a and 62b, respectively. When the movable member 66b is displaced by a predetermined amount toward the plate member 60, the locate pin 70b attached to the movable member 66b via the support plate 68b engages with the swing arm mounting hole 22b of the pivot plate 24b. When the locate pin 70b is displaced by a predetermined amount in the direction of arrow F, the end stopper 76 attached to the movable member 66b abuts the stopper 74 of the plate member 60, and the displacement operation is stopped. As a result, the swing arm mounting hole 22b is positioned in the vehicle width direction of the main body 40 in the bracket mounting device. On the other hand, the locate pin 70a attached to the movable member 66a via the support plate 68a is displaced by a predetermined amount in the direction of arrow E and engages with the swing arm mounting hole 22a. Next, the head pipe 14 is positioned by the head pipe clamp mechanism 46. Therefore, the lower end of the front fork insertion hole 12 formed in the head pipe 14 is engaged with the lower clamp member 94, and the upper clamp member 100 is displaced in the direction of arrow G under the driving action of the cylinder 96. In this case, the front end of the upper clamp member 100 is
Positioning is performed by engaging with the upper end of 2. As described above, the body frame 10 is positioned and corrected with respect to the main body 40 of the bracket mounting device by the pivot clamp mechanism 44 and the head pipe clamp mechanism 46. In this case, an error such as a twist due to welding heat generated at the time of assembling the body frame 10 is corrected by the pivot clamp mechanism 44 and the head pipe clamp mechanism 46. When the positioning of the body frame 10 is completed, the side bases 48A and 48B are then displaced toward both sides of the body frame 10 under the driving action of the side base driving mechanisms 122 and 124. That is, in FIG. 2 and FIG. 5, each cylinder constituting the side base driving mechanisms 122 and 124
When the 134 is driven, the cylinder rod 138 is displaced in the direction of arrow E, and the frame 10 constituting the side bases 48A and 48B is displaced.
6 and 108 are displaced in the directions of arrows E and F via the guide bars 126a and 126b while being supported by the guide members 130a and 130b. And these frames 10
When 6 and 108 are displaced and approach each other by a predetermined amount, the pillars 110a, 11
The recesses 146a, 146b and 154a at both ends of the side base stoppers 144 and 152 between 0b and 112a and 112b,
Stoppers 148a, 148b and 156a, 156b engage with 154b,
The movement of the frames 106 and 108 stops (see FIGS. 2 and 3). At this time, the brackets 34a to 34q excluding the brackets 34i and 34q are positioned with respect to the predetermined portions of the vehicle body frame 10 by the bracket clamp mechanisms 50a to 50q disposed at predetermined portions of the frames 106 and 108. In addition,
The brackets 34i and 34q clamped by the bracket clamp mechanisms 50i and 50q are positioned relative to the vehicle body frame 10 by being displaced in the direction of the arrow H via the connecting plate 226 by driving the forward / backward cylinder 222 (see FIG. 9 and 10). Next, in the state where the brackets 34a to 34q are positioned at predetermined portions of the body frame 10 as described above, each of the brackets 34a to 34q is
Is performed. In this case, each of the brackets 34a to 34q is accurately positioned with respect to the swing arm mounting holes 22a and 22b of the pivot plates 24a and 24b, and a bracket clamp mechanism disposed at a predetermined portion of the side bases 48A and 48B. The relative positional relationship is accurately set by 50a to 50q. Therefore, the bracket
34a to 34q will be attached very accurately to the body frame 10. [Effects of the Invention] As described above, according to the present invention, after assembling the vehicle body frame, the pivot portion and the head pipe portion are subjected to positioning correction with respect to the jig by using the pivot clamp mechanism and the head pipe clamp mechanism, and then, The bracket is positioned with respect to the vehicle body frame by a plurality of bracket clamp mechanisms that hold a predetermined bracket and are disposed on both sides of the vehicle body frame. In this case, since the body frame is positioned by the pivot clamp mechanism and the head pipe clamp mechanism, the bracket is accurately positioned at a predetermined position of the body frame with respect to the pivot portion. Further, the relative positional relationship between the brackets is accurately set by the relative positional relationship between the plurality of bracket clamp mechanisms. As a result, the exterior member such as the side frame can be attached to the vehicle body frame in a correct posture via the bracket. In particular, since the exterior members such as the cowl divided at the front and rear of the vehicle body are joined with high precision, there is obtained an advantage that the appearance of the completed vehicle is extremely good. As described above, the present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to these embodiments, and various improvements and design changes can be made without departing from the gist of the present invention. Of course.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an assembled structure of a motorcycle body frame to which a bracket mounting device according to the present invention is applied, FIG. 2 is a schematic structural perspective view of the bracket mounting device according to the present invention, 3 is a side view of the vehicle body frame positioned by the pivot clamp mechanism and the head pipe clamp mechanism in the bracket mounting device according to the present invention. FIG. 4 is a perspective view showing the configuration of the pivot clamp mechanism in the bracket mounting device according to the present invention. FIG. 7 is a perspective view showing the configuration of a side base drive mechanism in the bracket mounting device according to the present invention. FIG. 6 is a side view showing the positional relationship between the bracket clamp mechanism and the vehicle body frame in the bracket mounting device according to the present invention. 9 to 10 show a bracket clamping mechanism in a bracket mounting device according to the present invention. Configuration perspective and a front diagram. 10 Body frame, 14 Head pipes 24a, 24b Pivot plates 34a to 34q Bracket 40 Body, 42 Base plate 44 Pivot clamp mechanism 46 Head pipe clamp mechanisms 48A, 48B ... Side bases 50a to 50q ... Bracket clamp mechanisms 70a, 70b ... Locate pins 78a, 78b ... Cylinder 94 ... Lower clamp member, 96 ... Cylinder 100 ... Upper clamp members 106, 108 ... Frames 122, 124 …… Side base drive mechanism 134 …… Cylinder 144, 152 …… Side base stopper

Continuation of front page                   (56) References JP-A-52-135138 (JP, A)                 JP-A-54-102737 (JP, A)                 JP-A-54-113141 (JP, A)                 JP-A-60-191766 (JP, A)                 Shokai Sho 61-133485 (JP, U)

Claims (1)

(57) [Claims] A bracket mounting method for mounting an exterior member on a motorcycle frame, comprising, after assembling the motorcycle frame, performing positioning correction of a pivot portion and a head pipe portion of the motorcycle frame on the jig on the jig. Further, a plurality of brackets are positioned with respect to the motorcycle frame in a mutual positional relationship based on a design dimension value of the exterior member with reference to the pivot portion, and then, using the joining means, for the motorcycle. A bracket mounting method for a motorcycle frame, wherein the brackets are mounted on the frame. 2. A pivot clamp mechanism that corrects the positioning of the pivot portion of the motorcycle frame with respect to the jig; a head pipe clamp mechanism that corrects the positioning of the head pipe portion of the motorcycle frame with respect to the jig; and an exterior attached to the motorcycle frame. A plurality of bracket clamp mechanisms for holding a bracket for mounting members in a predetermined posture, wherein each of the bracket clamp mechanisms is based on a design dimension value of an exterior member of the motorcycle frame with respect to the pivot portion. And first and second side bases provided opposite to both sides of the motorcycle frame so as to be able to approach and move toward the motorcycle frame under the action of driving means, When the first and second side bases move close to each other, the pivot portion is used as a reference. Positioning means for stopping the first and second side bases at a predetermined position based on a design dimension value of the exterior member of the motorcycle frame, and positioning each of the bracket clamp mechanisms with respect to the motorcycle frame. A bracket mounting device for a motorcycle frame, comprising: