Title of Invention

"FRAME STRUCTURE FOR MOTORCYCLE"

Abstract A frame structure in a motorcycle having a main frame extending rearwardly from a head pipe on which a front wheel is steerable supported, a pivot frame having an upper end welded to a side of a rear end of the main frame and extending downwardly, the pivot frame supporting a pivot of a rear arm on which a rear wheel is swingably supported, and a seat rail having a front end welded to a side of the rear end of the main frame and extending rearwardly, the seat rail supporting a seat on an upper surface thereof, characterized in that at least one of the upper end of the pivot frame and the front end of the seat rail is bent such that both said ends extend in the same direction as each other and are arranged in line with each other. to
Full Text [ Technical field of the invention]
The present invention relates to a fr,ame structure suitable for use in a motorcycle^or the like.
[ Prior art]
One conventional frame structure suitable for a motorcycle disclosed in Japanese patent publication No. 4-71747 has a main frame in the form of a round pipe extending rearwardly from a head pipe on which a front wheel is steerably supported, a pivot frame having an upper end welded to a side of a rear end of the main frame and extending downwardly, and a seat rail having a front end welded to a side of the rear end of the main frame and extending rearwardly .
The upper end of the pivot frame has its axis extending vertically and crossing the axis of the main frame and the axis of the front end of the seat rail.
Each of the pivot frame and the seat rails comprises a round pipe. The pivot frame has an intermediate pivot to which the front end of a rear arm is attached by a shaft, with a rear wheel supported on the
rear end of the rear arm. A seat is supported on the seat rail.
[Problems to be solved by the invention]
Because the axis of the pivot frame at its attachment region crosses the axis of the main frame, the pivot frame and the seat rail are welded in different directions, respectively.
Therefore, since the pivot frame and the seat rail need to be installed in different welding processes, the entire welding operation is complex and carried out in a large number of steps, and cannot easily be automatized.
Inasmuch as the pivot frame and the seat rail are welded separately from each other, different accuracy levels of the respective welding processes tend to greatly
affect the overall welding accuracy.
r n r\r\ n i [_ u u u u j
The main frame in the form of a round pipe makes it difficult to fabricate an abutment structure of the upper end of the pivot frame due to the accuracy requirement for a cut edge thereof. Furthermore, it is difficult to weld the pivot frame to the main frame because
the pivot frame needs to be welded along a three-dimensional line in the circumferential direction of the main frame.
The welding line cannot sufficiently be increased though increasing the welding line is desirable for increasing the welding strength.
[Means for solving the problems]
*
To solve the above problems, there is provided in accordance with the present invention a frame structure in a motorcycle having a main frame extending rearwardly from a head pipe on which a front wheel is steerably supported, a pivot frame having an upper end welded to a side of a rear end of the main frame and extending downwardly, the pivot frame supporting a pivot of a rear arm on which a rear wheel is swingably supported, and a seat rail having a front end welded to a side of the rear end of the main frame and extending rearwardly, the seat rail supporting a seat on an upper surface thereof, characterized in that at least one of the upper end of the pivot frame and the front end of the seat rail is bent such that both the ends extend in the same direction as each other and are arranged in line with each other.
The main frame may comprise a round pipe, and the upper end of the pivot frame and the front end of the seat rail may be staggered longitudinally substantially along the axis of the main frame.
[Effect of the invention]
At least one of the upper end of the pivot frame and the front end of the seat rail is bent such that both the ends extend in the same direction as each other and are arranged in line with each other. Therefore, the portions of the pivot frame and the seat rail which are welded to the main frame are positioned on a single continuous welding line.
Consequently, since the upper end of the pivot frame and the front end of the seat rail can be welded along the single continuous welding line, they can be welded with increased accuracy in a reduced number of steps. In addition, the welding process can easily be automatized .
If the main frame comprises a round pipe, and the upper end of the pivot frame and the front end of the seat
rail are staggered longitudinally substantially along the axis of the main frame, then the upper end of the pivot frame and the front end of the seat rail can be welded along a straight welding line substantially along the axis of the main frame.
Since the welding process can be effected along a straight line substantially parallel to the axis of the main frame, the upper end of the pivot frame and the front
i
end of the s*eat rail can easily and accurately be welded to the main frame even though the main frame comprises a round pipe. Furthermore, the upper end of the pivot frame and the front end of the seat rail, which serve as joints to the main frame, may be simplified in shape.
In addition, the upper end of the pivot frame and the front end of the seat rail may be welded along sufficient welding lines, respectively, and hence have sufficient levels of weldinq strenath.
Therefore, the subject of invention relates to a frame structure in a motorcycle having a main frame extending rearwardly from a head pipe on which a front wheel is
Steerabl M'supported, a pivot frame having an upper end welded
J to a side of a rear end of the main frame and extending
downwardly, the pivot frame supporting a pivot of a rear arm on which a rear wheel is swingably supported, and a seat rail having a front end welded to a side of the rear end of the main frame and extending rearwardly, the seat rail supporting a seat on an upper surface thereof, characterized in that at least one of the upper end of the pivot frame and the front end of the seat rail is bent. s-biefe both said ends extend
in the same direction as each other and are in line
[BRIEF DESCRIPTION OF THE DRAWINGS]
[FIG. 1] is an enlarged fragmentary side elevational view of a frame of a motorcycle; .
[FIG. 2 ] is a left-hand side elevational view of the motorcycle;
[Fid. 3] is a right-hand side elevational view of the motorcycle;
(FIG. 4] is an enlarged side elevational view of a portion of the motorcycle; and
[FIG. 5] is an enlarged fragmentary plan view of a main frame portion.
[Embodiment of the invention]
An embodiment of the present invention,
constructed as a customized motorcycle, will be described below with reference to the drawings. FIG. 1 is an
enlarged fragmentary side elevational view of a joint region of a main frame, a seat rail, and a pivot frame of the motorcycle. FIG. 2 is a left-hand side ejevational view of the motorcycle. FIG. 3 is a right-hand side elevational view of the motorcycle. FIG. 4 is a side elevational view of a motorcycle frame. FIG. 5 is an enlarged fragmentary plan view of the joint region shown in FIG. 1.
As shown in FIGS. 2 and 3, the motorcycle includes a front fork 2 which supports a front wheel 1 and has an upper portion angularly movably supported on a head pipe 5 by a bottom bridge 3 and a top bridge 4. A handlebar 6 is attached to and extends from the top bridge 4, and has grips 7 positioned rearwardly.
The head pipe 5 is mounted on a front end of a main frame 10 which extends longitudinally along the center of the motorcycle. A pair of laterally spaced down frames 11 extends obliquely downwardly laterally from a lower portion of the head pipe 5. The down frames 11 have respective lower ends contiguous to a lower frame 12 that extends longitudinally substantially horizontally.
A pair of laterally spaced pivot frames 13 extends downwardly from a rear end of the main frame 10 substantially parallel to the down frames 11 .as viewed in side elevation. The pivot frames 13 have respective lower ends connected to lower portions of a pair of laterally spaced rear stays 14 extending obliquely upwardly and rearwardly contiguously from a rear end of the lower frame 12.
A pair of laterally spaced seat rails 15 extends substantially horizontally rearwardly from the rear end of the main frame 10. The seat rails 15 have respective rear ends joined to respective upper portions of the rear stays 14.
The rear stays 14 are bent in the vicinity of the joined ends of the seat rails 15 and extend substantially horizontally rearwardly. The rear stays 14 have outer side surfaces covered with grab rails 16 mounted in place by attachments 17. The rear stays 14 have respective rear ends connected to a pair of laterally spaced auxiliary frames 18 extending rearwardly in the direction in which the rear stays 14 extend. Rear flashing indicators 19 are supported on the rear ends of the rear stays 14.
The main frame 10, the down frames 11, the lower frame 12, the pivot frames 13, the seat rails. 15, and the rear stays 14 jointly make up a motorcycle frame. The main frame 10, the down frames 11, the lower frame 12, and the seat rails 15, which serve as a front portion of the motorcycle frame, provides a cradle-shaped frame structure by which an engine 20 is supported.
The engine 20 draws air from an air cleaner in a side cover 22 through a carburetor 21, and discharges exhaust gases through an exhaust pipe 23 and mufflers 24.
The engine 20 has a crankcase 25 on which a starter motor 26 is mounted. The engine 20 drives a sprocket 30 coaxial with a rear wheel 29 through a drive gear 27 and a chain 28.
The rear wheel 29 is supported on rear ends of rear arms 31 whose front ends are vertically swingably mounted by a shaft to a pivot 32 on intermediate portions of the pivot frames 13. Dampers 33 are connected between rear portions of the rear arms 31 and upper portions of the rear stays 14.
A fuel tank 34 is supported on the main frame 10 and supports on a front upper surface thereof, an indicator panel 35 including various indicators and meters. A rider's seat 36 is supported on the seat rails 15 behind the fuel tank 34. [0028}-.
Behind the rider's seat 36, there is positioned a passenger's seat 37 supported on a rear cowl 38. A back rest 39 is disposed behind the passenger's seat 37 and mounted on a support 40 attached to the grab rails 16.
A rear fender 41 is attached a lower portion of the rear cowl 38. A tail light 42 and a mud guard 43 are mounted on a rear end of the rear fender 41 and supported on the auxiliary frames 18.
Front steps 45, a brake pedal 46, and a shift pedal 47 are positioned forwardly of a lower portion of the engine 20 so that the rider of the motorcycle can extend the legs forwardly in a customized-motorcycle riding fashion. {0031]-
The motorcycle also has a side stand 48, rear
steps 49, a wheel 50 of light alloy or the like, brake disks 51, brake calipers 52, a front fender 53, a head light 54, front flashing indicators 55, a horji 56, front side covers 57 laterally covering an upper portion of the cylinder of the engine 20, and reinforcing pipes 58.
Details of the frame structure will be described below. As shown in FIGS. 1 through 3, each of the pivot frames 13 comprises a round pipe, and includes a bent end portion 61 bent forwardly and having a flattened upper end 60.
The pivot frames 13 have an attachment axis LI near the upper ends 60 which is in substantial agreement with an axis LO of the main frame 10 in the form of a round pipe. The upper ends 60 have upper and lower longer sides 62 held against and welded to sides of the main frame 10 in a relatively long range along welding lines 63 that extend along the longer sides 62.
The seat rails 15 are attached in a manner similar to the pivot frames 13. The seat rails 15 include respective flattened front ends 70, and have an attachment axis L2 near the front ends 70 which is in substantial
agreement with the axis LO of the main frame 10.
The front ends 70 have upper and lowejr longer sides 72 held against and welded to sides of the main frame 10 in a relatively long range along welding lines 73 that extend along the longer sides 72. ^1036]*
These welding lines 63, 73 are positioned continuously in line with each other in sandwiching relation to welding lines 80 in an intermediate non-welding region. The welding lines 63, 73, 80 are continuously formed substantially in one process.
As shown in FIGS. 2 and 3, the upper ends 60 and the bent end portions 61 of the pivot frames 13 and the front ends 70 of the seat rails 15 are positioned in partially overlapping relation and staggered longitudinally
A process of assembling the frame structure and advantages thereof will be described below. As shown in FIGS. 1 through 3, since the attachment axes Ll, L2 lie substantially parallel to the axis LO of the main frame 10, the longer sides 62, 72 are held in contact with the sides
of the main frame 10 in long ranges.
When the upper ends 60 and the bent end portions 61 of the pivot frames 13 and the front ends 70 of the seat rails 15 are welded to the main frame 10, they are welded along the welding lines 63, 73 which are relatively long.
Therefore, the pivot frames 13 and the seat rails 15 are secured to the sides of the main frame 10 with sufficient welding strength.
Because the upper ends 60 and the front ends 70 are staggered longitudinally in overlapping relation as viewed in side elevation, the welding lines 63, 73 are arranged in line with each other, forming single continuous welding lines together with the welding lines 80, as shown in FIG. 1.Therefore, the upper ends 60 of the pivot frames 13 and the front ends 70 of the seat rails 15 can be welded in a single welding process for each of the upper and lower portions thereof. Thus, the welding process can be carried out in a reduced number of steps and can be automatized.
In addition, inasmuch as the upper ends 60 of the pivot frames 13 and the front ends 70 of the seat rails 15 are simultaneously welded, the overall welding accuracy does not depend on the welding accuracy of each of the pivot frames 13 and the seat rails 15, resulting in a welded structure with an excellent welding failure absorption capability.
Even though the main frame 10 comprises a round pipe, since the upper ends 60 of the pivot frames 13 and the front ends 70 of the seat rails 15 are staggered longitudinally substantially along the axis LO of the main frame 10, they can be welded to the main frame 10 along straight welding lines which extend substantially along the axis LO of the main frame 10.
Because the welding process is carried out on straight lines which extend substantially along the axis LO of the main frame 10, the upper ends 60 of the pivot frames 13 and the front ends 70 of the seat rails 15 can easily and accurately be welded to the main pipe 10 though the main pipe comprises a round pipe. Moreover, the upper ends 60 of the pivot frames 13 and the front ends 70 of the seat rails 15, which serve as joints to the main frame 10, may
be of a relatively simple shape.
Additionally, the welding lines at the upper ends 60 of the pivot frames 13 and the front ends 70 of the seat rails 15 can be sufficiently long for sufficient welding strength.
The welding lines 80 in the intermediate non-welding region may not necessarily be formed, but the pivot frames 13 and the seat rails 15 may be welded while skipping the welding lines 80. However, the welding process is facilitated by forming the welding lines 80. [0018] -
The main frame 10 may not be a round pipe, but may be a cast member having a rectangular cross section or the like at least in its rear portion. With such a modification, the upper ends 60 of the pivot frames 13 and the front ends 70 of the seat rails 15 may not necessarily be staggered in the longitudinal direction. Instead, the upper ends 60 of the pivot frames 13 and the front ends 70 of the seat rails 15 may be staggered obliquely vertically, and the front ends 70 of the seat rails 15 may be bent largely in the vertical direction in line with the upper ends 60 of the pivot frames 13.
[Description of reference numerals]
10: main frame, 13: pivot frame, 15: seat rail, 60: upper end of the pivot frame, 63: welding line, 70: front end of the seat rail, 73: welding line.



We claim:
1. A frame structure for a motorcycle having a main frame extending rearwardly from a head pipe on which a front wheel is steerable
supported, a pivot frame having an upper end welded to a side of a rear end of the main frame and extending downwardly, the pivot frame supporting a pivot of a rear arm on which a rear wheel is swingably supported, and a seat rail having a front end welded to a side of the rear end of the main frame and extending rearwardly, the seat rail supporting a seat on an upper surface thereof, characterized in that at least one of the upper end of the pivot frame and the front end of the seat rail is bent, both said ends extend in the same direction as each other and are placed in line with each other.
2. A frame structure in a motorcycle as claimed in claim 1, wherein said
main frame has a round pipe, and the upper end of the pivot frame
and the front end of the seat rail are staggered longitudinally along
the axis of the said main frame.
3. A frame structure in a motorcycle substantially as hereinbefore
described with reference to and as illustrated in the accompanying
drawings.

Documents:

3298-del-1997-abstract.pdf

3298-del-1997-claims.pdf

3298-del-1997-correspondence-others.pdf

3298-del-1997-correspondence-po.pdf

3298-del-1997-description (complete).pdf

3298-del-1997-drawings.pdf

3298-DEL-1997-Form-1.pdf

3298-del-1997-form-13.pdf

3298-del-1997-form-19.pdf

3298-del-1997-form-2.pdf

3298-del-1997-form-3.pdf

3298-del-1997-form-4.pdf

3298-del-1997-form-6.pdf

3298-del-1997-gpa.pdf

3298-del-1997-petition-138.pdf

abstract.jpg


Patent Number 215250
Indian Patent Application Number 3298/DEL/1997
PG Journal Number 10/2008
Publication Date 07-Mar-2008
Grant Date 22-Feb-2008
Date of Filing 18-Nov-1997
Name of Patentee HONDA GIKEN KOGYO KABUSHIKI KAISHA
Applicant Address 1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 HITOSHI SUZUKI C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
2 SEIJI HANAFUSA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
PCT International Classification Number B62K 11/02
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 HEI-8-341855 1996-12-20 Japan