Technical Field
[0001] The present invention generally relates to a motorcycle and
particularly, but not exclusively relates to a body frame for said motorcycle. Background
[0002] Typically, motorcycles include a body frame extending
rearwardly throughout a length of a motorcycle. Particularly, the body frame includes a head pipe, a main frame extending rearwardly from said head pipe towards an intermediate portion thereof and then extending downwardly towards a rear engine mounting bracket, a down frame extending downwardly and rearwardly from said head pipe towards a front engine mounting bracket, a pair of upper frames extending rearwardly from the main frame, and a pair of side frames. extending forwardly downwards from the pair of upper frames towards the main frame. Typically, an engine at its front end is mounted to the down frame, and at its rear end is mounted to the main frame. Thus, a front portion of the body frame including the head pipe, the main frame, the down frame, and the engine forms a cage like structure. Particularly, a front engine mounting bracket and the rear engine mounting bracket is used to mount the engine to the down tube and the main frame respectively. The engine functions as a stressed member in said cage like structure.
[0003] Load distribution is an important aspect to be ensured in the
body frame where engine is used as the stressed member. In conditions where weight of the engine is increased due to change in design of the

same, the body frame has to be sufficiently reinforced to bear load from
the engine. However, while providing enhanced rigidity to the body frame,
it is also important to ensure that weight of the body frame does not
increase substantially. Besides, it is also essential to ensure that the
engine is reliably mounted to the body frame without involving
cumbersomeness in assembly.
Summary of the Invention
[0004] The present invention has been made in view of the above
circumstances.
[0005] It is an object of the present invention to provide a
motorcycle including a body frame having enhanced rigidity.
[0006] It is another object of the present invention to provide a body
frame which facilitates ease of engine mounting.
[0007] It is yet another object of the present invention to provide a
body frame which facilitates mounting of a crash guard and an engine
guard without involving the use of additional individual mounting brackets
or fasteners.
[0008] It is still another object of the present invention to provide a
body frame which facilitates effective load distribution from the engine.
[0009] Accordingly, as per an aspect of the present invention, a
motorcycle is provided, which comprises a body frame, and an engine
suspendedly supported to said body frame. Particularly, the body frame
includes a head pipe, a main frame extending rearwardly from said head

pipe, with at least a portion of the main frame extending downwardly from an intermediate portion of the body frame, a reinforcement bracket rigidly attached to the head pipe and the main frame on either sides, a pair of down frames separated in a motorcycle width direction and extending downwardly and rearwardly from said reinforcement bracket, a bridge tube sandwiched between the reinforcement bracket and extending from the head pipe towards at least a portion of the main frame and rigidly attached thereto, a pair of upper frames extending rearwardly from the main frame, and a pair of side frames extending forwardly and obliquely downwards from said pair of upper frames towards a rear engine mounting bracket. The engine is disposed in a front portion of the body frame. Particularly, the engine is supported below the bridge tube and between the pair of down frames and the main frame.
[0010] As per an embodiment of the present invention, the engine is
mounted to the main frame by means of a rear engine mounting bracket, and to each down frame of the pair of down frames by means of a C shaped bracket. Particularly, the C shaped bracket is attached to each down frame of the pair of down frames individually, and is adapted to receive a front portion of the engine.
[0011] According to an aspect of the present invention, the C
shaped bracket is detachably attached to a lower portion of the pair of down frames by means of fasteners. The C shaped bracket is disposed in . a manner such that at least a portion of the same is sandwiched between

the pair of down frames. In other words, at least a portion of the C shaped
bracket extends in a motorcycle width direction and covers at least
partially a front portion of the engine when viewed from a motorcycle front
direction. The C shaped bracket thus disposed is adapted to receive a
crash guard mounting bracket and an engine guard apart from the engine,
thereby eliminating the need for separate mounting structures to be
provided on the body frame, and thereby aiding in reducing overall weight
of the body frame. Moreover, since the C shaped bracket is individually
attached to each down frame of the pair of down frames, the engine can
be easily handled and attached to each side of the pair of down frames,
thus facilitating ease of engine assembly. Problems relating to
misalignment of the C shaped bracket with the pair of down frames are
also eliminated since the same is individually mounted to each down
frame of the pair of down frames rather than providing the same as a
single piece structure. Moreover, casting of the C shaped bracket provided
as per the present embodiment is also less complex.
[0012] According to another aspect of the present invention, in
order to improve rigidity of the body frame, and to ensure load distribution in the front portion of the body frame, the reinforcement bracket includes at least a pair of reinforcement plates, which is rigidly attached to the reinforcement, bracket. Further, at least one cross tube is sandwiched between the at least a pair of reinforcement plates in a manner such that it extends in a motorcycle width direction from both sjdes of the bridge tube.

Additionally, since the pair of down frames is rigidly attached to the
reinforcement bracket, said reinforcement bracket including the at least a
pair of reinforcement plates for local strengthening, load borne by the pair
of down frames is transferred to the at least one cross tube. Further load
from the at least one cross tube is transferred to the bridge tube, and from
the bridge tube to the main frame. Furthermore, since the bridge tube is
also attached to the head pipe at its front end, load is also transferred to
the head pipe. Thus, load distribution is ensured throughout the front
portion of the body frame.
[0013] Summary provided above explains the basic features of the
invention and does not limit the scope of the invention. The nature and
further characteristic features of the present invention will be made clearer
from the following descriptions made with reference to the accompanying
drawings.
Brief Description of Drawings
[0014] The above and other features, aspects, and advantages of
the subject matter will be better understood with regard to the following
description and accompanying drawings where:
[0015] FIG.1 is a side view of a motorcycle including a body frame
in accordance with an embodiment of the present invention.
[0016] FIG.2 is a side view of a body frame of a motorcycle in
accordance with an embodiment of the present invention..

[0017] FIG.3 is a side view of the body frame depicting a C shaped
bracket in accordance with an embodiment of the present invention.
[0018] FIG-4 is a front view of the body frame in accordance with an
* embodiment of the present invention.
[0019] FIG.5 is a perspective view of a C shaped bracket in
accordance with an embodiment of the present invention.
[0020] FIG.6 is a side view of the body frame depicting an engine
guard as mounted to the C shaped bracket in accordance with an embodiment of the present invention.
[0021] FIG.7 is a side view of the body frame depicting a crash
guard as mounted to the C shaped bracket in accordance with an embodiment of the present invention.
[0022] FIG.8 is a cross sectional view of the body frame depicting a
cross section of a reinforcement bracket taken along line X-X.
Detailed Description of the Preferred Embodiments
[0023] The present subject matter described herein relates to a
body frame of a motorcycle and particularly relates to a means for mounting the engine and for improving load distribution in said body frame where the engine is a stressed member.
[0024] Exemplary embodiments detailing features of the body
frame, in accordance with the present invention will be described hereunder with reference to the accompanying drawings. Various aspects

of different embodiments of the present invention will become discernible from the following description set out hereunder.
[0025] A general description of a motorcycle 100 having a body
. frame 10 in accordance with an embodiment of the present invention is made with reference to FIG.1
[0026] FIG- 1 illustrates a side view of a motorcycle 100 in
accordance with the present invention. The motorcycle 100 includes a
body frame 10 forming a body framework thereof. A head pipe 11 is
provided at a front end of the body frame 10. The head pipe 11 supports a
steering shaft (not shown) rotatably in a certain range. In an upper portion
of the head pipe 11, a handlebar 25 is rotatably integrally connected to the
steering shaft. The handlebar 25 is used to steer the motorcycle 100 and
is connected to a front wheel 26 through the steering shaft. An upper
portion of the front wheel 26 is covered by a front fender 27 which
prevents mud and water from getting deflected towards the steering shaft.
Further, a front fork assembly 28 is mounted over the front fender 27.
[0027] In a front portion of the front fork assembly 28, a lighting
device such as a headlamp 29, a pair of signalling devices such as turn
signal lamps 30, a display device such as a speedometer (not shown) etc
are housed by a holding structure 31 mounted thereto.
[0028] Furthermore, in a front portion of the body frame 10 a fuel
tank 32 is arranged immediately behind the handlebar 25 and is disposed over an engine 20.

[0029] A seat 36 is disposed behind the fuel tank 32. The seat 36
includes a front rider portion and rear pillion portion. In one embodiment the front rider portion and the rear pillion portion are included as a one continuous portion of the seat 36. In another embodiment, the front rider portion and the rear pillion portion may be included as two separate portions of the seat 36.
[0030] Suspension systems are provided for comfortable steering of
the motorcycle 100 on the road. The front fork assembly 28, which forms the front suspension system, serves as rigidity component just like the body frame. The front fork assembly 28 clamped to the head pipe 11 through an upper bracket (not shown) and a lower bracket (not shown) is capable of being moved to the left and right. Further, a rear suspension system, which is a hydraulic damped arrangement, is connected to the body frame 10.
[0031] The engine 20 is mounted to a front lower portion of the body
frame 10 by means of an engine mounting bracket. The engine 20 is equipped with an exhaust system that includes an exhaust pipe (not shown) connected to the engine 20 and a muffler (not shown) connected to the exhaust pipe. The muffler (not shown) extends rearwards along the right side of the rear wheel 40.
[0032] Further, a swing arm 41 extending rearwards is swingably
connected to a lower rear portion of the body frame 10. The rear wheel 40 is rotatably supported at a rear end of the swing arm 41. Power from the

engine 20 is transmitted to the rear wheel 40 through a power drive mechanism, such as a drive chain, so as to drive and rotate the rear wheel 40.
[0033] A rear fender 45 for covering an upper side of the rear wheel
40 is mounted to a rear portion of body frame 10 to prevent mud and water splashed by the rotating rear wheel 40 from entering the muffler, the engine 20 and other parts disposed close by.
[0034] To enhance the overall aesthetics of the motorcycle 100 and
to prevent undesired foreign particles from entering parts of the two wheeled vehicle, a plurality of rear covers 50 is attached to a rear portion of the body frame 10.
[0035] The body frame 10 as per the present embodiment is
elaborated with reference to FIG.2. The body frame 10 suspendedly supports the engine 20 in a front lower portion thereof. The body frame 10 as per an embodiment includes the head pipe 11, a main frame 12 extending rearwardly from the head pipe 11 up to its intermediate portion 12a, and extending downwardly therefrom, a reinforcement bracket 13 rigidly attached to the head pipe 11 and the main frame. 12 on either sides, a pair of down frames 14 separated in a motorcycle width direction and extending downwardly and rearwardly from the reinforcement bracket 13, a bridge tube 15 sandwiched between the reinforcement bracket 13 and extending rearwardly from the head pipe 11 towards at least a portion of the main frame 12 and rigidly attached thereto, a pair of upper frames 16

extending rearwardly from the main frame 12, and a pair of side frames 17 extending forwardly and inclinedly downwards from the pair of upper frames 16. Further, the body frame 10 includes a rear engine mounting bracket 18 combinedly mounted to the main frame 12 and the pair of side frames 17 to receive a rear portion of the engine 20. Furthermore, the body frame 10 includes at least one C shaped bracket 19 mounted to the pair of down frames 14 in order to receive a front portion of the engine 20. Particularly, the C shaped bracket 19 is detachably attached to each down frame of the pair of down frames 14. Preferably/two long bolts are used to detachably attach the C shaped bracket 19 to each down frame of the pair of down frames 14.
[0036] Particularly, since the C shaped bracket 19 extends curvedly
towards the engine 20, a bulging front portion of the engine 20 can be accommodated at least partially within the C shaped bracket 19. Thus, even high capacity engines can be comfortably accommodated and supported by said C shaped bracket 19. As may be seen in FIG.3, the C shaped bracket 19 is provided with at least two engine mounting holes 19a, 19a to receive the engine 20.
[0037] FIG.4 illustrates a front view of the body frame 10 depicting a
front side of the C shaped bracket 19. As may be seen, at least a portion of the C shaped bracket 19 extends in a motorcycle width direction from each down frame of the pair of down frames 14 so as to at least partially cover.a front portion of the engine 20. Further, a front portion of the C

shaped bracket 19 is provided with an engine guard mounting bracket 19b
for receiving an engine guard 22 (shown in FIG.6), provided to protect
vulnerable parts of the engine 20. In other words, the engine guard
mounting bracket 19b is integrally formed with the C shaped mounting
bracket 19. Preferably, the engine guard mounting bracket 19b is provided
in a front portion of the C shaped bracket 19, and in a manner such that it
extends in a motorcycle width direction from a peripheral portion of said C
shaped bracket 19. In the present embodiment, the engine mounting
bracket 19b is provided on one of the two C shaped brackets 19 that is
adapted to be mounted to the pair of down frames 14. However, in another
embodiment, the engine guard mounting bracket 19b may be provided on
each C shaped bracket 19 mounted to each down frame of the pair of
> down frames 14. Thus, provision of the C shaped bracket 19 aids in
eliminating the need for a separate mounting structure for the engine
guard 22.
[0038] FIG-5 illustrates a perspective view of the C shaped bracket
19. In the present embodiment of the C shaped bracket 19 includes at
least two engine mounting holes 19a, 19a to receive the engine 20, at
least two top mounting holes 19c,19c for mounting to the pair of down
i frames 14, and at least one engine guard mounting bracket 19b.
Preferably, the engine guard mounting bracket 19b is provided with a pip
19bb to receive the engine guard 22.

[0039] FIG.6 illustrates the engine guard 22 as mounted to the C
shaped bracket 19. As may be seen, the engine guard 22 is provided with
a single point mounting at its front portion to the C shaped bracket 19.
Particularly, the pip 19bb (shown in FIG.4) provided in the engine guard
mounting bracket 19b aids in the location and fastening of the engine
guard 22 with the C shaped bracket 19. Thus, the engine guard 22 may be
easily and conveniently mounted to the C shaped bracket 19.
[0040] Further, as shown in FIG.7, the C shaped bracket 19 is also
adapted to receive at least a portion of a crash guard 21 through a crash guard mounting bracket 21a. However, in another embodiment, the crash guard 21 may be directly mounted to the C shaped bracket 19. As per an aspect of the present invention, the crash guard mounting bracket 21a is adapted to be combinedly mounted to the pair of down frames 14 together with the C shaped bracket 19. Thus, at least a portion of the crash guard mounting bracket 21a overlaps with at least a portion of the C shaped bracket 19, so that the same may be combinedly mounted to the pair of down frames 14. In other words, the crash guard mounting bracket 21a is sandwich mounted together with the C shaped bracket 19 to the pair of down frames 14 through said at least two top mounting holes 19c,19c. Thus, since the crash guard mounting bracket 21a is sandwich mounted with the C shaped bracket 19, the need for individual fastening members such as bolts and nuts is eliminated, reducing part count and therefore the overall weight of the body frame 10.

[0041] ~ Thus, the front portion of the body frame 10 including the C shaped bracket 19 together with engine 20 forms a cage like structure. In the present embodiment, the engine 20 serves as stressed member. Load from the engine 20 suspendedly supported to the body frame 10 requires to be distributed throughout the front portion of the body frame 10 for enhancing overall durability of the body frame 10. Moreover, stiffness of the body frame 10 also needs to be increased while ensuring ride handling of the motorcycle.
[0042] Stiffness and load distribution achieved in the body frame 10
may be' explained with reference to FIG.8. As per the present embodiment, the reinforcement bracket 13 includes at least a pair of reinforcement plates 13a rigidly attached thereto on either sides thereof. Preferably, each reinforcement plate of the at least a pair of reinforcement plates 13a is rigidly attached to an inner side wall of the reinforcement bracket 13, on both sides of said reinforcement bracket 13. Thus, the pair of reinforcement plates 13a serves to stiffen the reinforcement bracket 13 locally. Further, at least a portion of each down frame of the pair of down frames 14 is rigidly attached to the reinforcement bracket 13 on each side thereof, and particularly on an outer surface of said reinforcement bracket 13. Additionally, at least one cross tube 21 is sandwiched between the at least a pair of reinforcement plates 13a in a manner such that at least a portion on one side of the cross tube 21 is rigidly attached to each reinforcement piate of the pair of rejnforcement plates 13a, and at least

another portion on the other side of the same is rigidly attached to the
bridge tube 15. Thus, the at least one cross tube 21 extends in a
motorcycle width direction from both sides of the bridge tube 15.
[0043] Thus, load from the front portion of the engine 20 is
transferred to the pair of down frames 14 through the C shaped bracket 19. Further, load from the pair of down frames 14 is transferred to the reinforcement bracket 13, the pair of reinforcement plates 13a, and to the at least one cross tube 21 from the reinforcement bracket 13. Further, load from the at least one cross tube 21 gets transferred to the bridge tube 15. Further, load gets transferred to the main frame 12 from the bridge tube 15, which is rigidly attached at its one end to the main frame 12. Some load is also transferred to the head pipe 11 through the bridge tube 15, which is rigidly attached at its other end to the head pipe 11. Thus, it is ensured that load is equally distributed to all parts of the front portion of the body frame, thus ensuring that there is no compromise in strength of any part of the body frame.
[0044] As it is apparent from the above teaching, provision of the C
shaped bracket aids in ease of engine mounting. It particularly aids in cases where the engine bulges in its front side and where the length of the i down frame has to be reduced in order to accommodate the engine. Mounting of individual C shaped brackets to the pair of down frames not only aids in easing assembly but also aids in reducing weight of the body frame.

[0045] While the present invention has been shown and described
with reference to the foregoing preferred embodiments, it will be apparent
to those skilled in the art that changes in form, connection, and detail may
be made therein without departing from the spirit and scope of the
invention as defined in the appended claims.

We Claim:
1. A body frame (10) for a motorcycle (100), said motorcycle (100) comprising an engine (20) suspendedly supported to said body frame (10), wherein said body frame (10) includes: a head pipe (11);
a main frame (12) extending rearwardly from the head pipe (11);
a reinforcement bracket (13) rigidly attached to the head pipe (11) on either sides and to the main frame (12) on either sides;
a pair of down frames (14) separated in a motorcycle width direction and extending downwardly and rearwardly from the reinforcement bracket (13);
a bridge tube (15) extending from said head pipe (11) towards said main frame (12), and rigidly attached thereto;
characterized in that, the body frame (10) further includes at least two C shaped brackets (19), each C shaped bracket (19) adapted to be detachably attached to each down frame of the pair of down frames (14), wherein at least a portion of said C shaped bracket (19) extends substantially in a motorcycle width direction, and wherein said C shaped bracket (19) is adapted to receive at least a front portion of the engine (20).

2. The body frame (10) as claimed in claim 1, wherein the C shaped bracket (19) includes at least two engine mounting holes (19a, 19a) for receiving the engine (20).
3. The body frame (10) as claimed in claim 1, wherein the C shaped bracket (19) integrally includes an engine guard mounting bracket (19b) to receive an engine guard (22).
4. The body frame (10) as claimed in claim 1, wherein the C shaped bracket (19) includes at least two top mounting holes (19c, 19c) to receive at least a portion of a crash guard (21).
5. The body frame (10) as claimed in claim 4, wherein said at least a portion of crash guard (21) includes a crash guard mounting bracket (21a).
6. A body frame (10) for a motorcycle (100), said motorcycle (100) comprising an engine (2Q) suspendedly supported to said body frame (10), wherein said body frame (10) includes:
a head pipe (11);
a.main frame (12) extending rearwardly from the head pipe (11);
a reinforcement bracket (13) rigidly attached to the head pipe (11)
on either sides and to the main frame (12) on either sides;
a pair of down frames (14) separated in a motorcycle width direction
and.extending downwardly and rearwardly from the reinforcement
bracket (13);

a bridge tube (15) extending from said head pipe (11) towards said main frame (12), and rigidly attached thereto; characterized in that, the reinforcement bracket (13) includes at least a pair of reinforcement plates (13a), each reinforcement plate of said at least a pair of reinforcement plates (13a) adapted to be rigidly attached to an inner side wall on both sides of said reinforcement bracket (13).
7. The body frame as claimed in claim 6, wherein the body frame (13) further includes at least one cross tube (21) rigidly attached between the at least a pair of reinforcement plates (13a) and at least a portion of the bridge tube (15).
8. The body frame as claimed in claim 7, wherein the at least one cross tube (21) extends in a motorcycle width direction from both sides of the bridge tube (15).