Motorcycle

A motorcycle having a swingable front frame, a stable, non-swingable main frame, a front cowling supported by the main frame and covering a forward part of the motorcycle and an extension projecting laterally outwardly from each side of the front cowling. An air stream rectifier is provided in each laterally projecting extension of the front cowling.

BACKGROUND OF THE INVENTION 
The present invention relates to a motorcycle capable of cornering at high 
speeds. 
When cornering or turning a motorcycle, for example, when driving or 
cornering along a circumferential path it is necessary for a driver to 
have his body banked together with the motorcycle or vehicle body to the 
lateral side of the vehicle body toward the circumferential center to 
balance or overcome centrifugal force resulting from such a turn. 
In a chassis frame of a conventional motorcycle, however, the front wheel 
supporting front frame and the rear wheel supporting main frame are formed 
integral. When banking such a vehicle body during cornering, the center of 
gravity of the entire vehicle body including the driver moves toward the 
lateral side of the body inside the turn because each frame banks 
simultaneously. Upon cornering during a high speed run, a greater extent 
or degree of banking is required which increases the change ratio of the 
center of gravity in proportion to the increase in speed. 
The front and rear wheels supported on the front frame and the main frame 
of a conventional motorcyle have substantially the same width and are 
formed to allow the vehicle body to bank for cornering. Accordingly, 
during cornering, the ground gripping areas of the front and rear wheels 
which bank laterally toward one side of the vehicle body decrease in 
proportion to the banking angle of each frame. 
Under these circumstances, the vehicle body is required to be banked to a 
larger extent when cornering at a considerable high speed such as during 
sports racing. Therefore, in a conventional motorcycle, the running speed 
of the motorcycle may have to be decreased during cornering depending upon 
several conditions. 
To overcome the aforesaid disadvantages, it is an object of the present 
invention to provide a motorcycle capable of cornering at a high speed and 
capable of more effectively controlling the air streams at the lateral 
sides of a vehicle body during running to obtain a greater running 
stability than that obtained with a conventional motorcycle. 
SUMMARY OF THE INVENTION 
The present invention provides a motorcycle comprising a chassis frame 
including a front frame suspending a front wheel and a main frame 
suspending a rear wheel, the front frame and the main frame are connected 
together with the front frame forward of the main frame, and includes a 
connecting axle disposed between the main frame and the front frame. The 
front frame is supported on the connecting axle for swinging movement 
toward each side of the chassis and a rear wheel is provided on the main 
frame which has a width sufficient to prevent the main frame from turning 
relative to the connecting axle. A front cowling is supported by the main 
frame and covers a forward part of the motorcyle supported by the front 
wheel and the front frame and includes an extension projecting laterally 
outwardly from each respective side of the front cowling. 
In the preferred embodiment an air stream rectifier is provided in each 
laterally projecting extension with each air stream rectifier defined by a 
front opening located at a forward end of the extension and an air passage 
provided internally of the extension and communicating the front opening 
with a rear opening. The rear opening may be provided in an upper or in a 
lateral side surface of the extension and, in the preferred embodiment, 
the air passage includes an air flow directing surface curving toward the 
rear opening. 
In a preferred embodiment a fluid cooling radiator is provided internally 
of the air passage and the lower surface of the extension curves 
rearwardly and upwardly to develop a downward force resulting from air 
flowing between the lower surface of the extension and a surface traversed 
by the motorcycle. 
An air intake opening and a second air passage may also be provided to each 
extension to provide a source of air for a carburetor or turbocharger. 
The motorcycle of the present invention thus has a swingable front frame, a 
stable, non-swingable main frame, and a front cowling providing lateral 
extensions. Air stream improving devices are provided on the extensions of 
the front cowling which is preferably mounted to the main frame, whereby 
the air stream improving devices may rectify the air stream flowing in a 
direction from the forward to the rearward part of the vehicle body during 
running. The air pressure is thus directed to force the vehicle body 
downwards toward the ground. Also, other parts such as a fluid cooling 
radiator may be provided at desired locations on or in the extensions. 
The present invention and the advantages provided thereby will be more 
fully understood with reference to the following detailed description of 
preferred embodiments of the invention and the claims taken together in 
conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The present invention will now be described in detail with reference to the 
accompanying drawings wherein like reference numerals and characters 
designate the same or like parts. 
With reference to FIG. 1, there is shown a perspective view of one 
embodiment of the invention wherein reference character "A" denotes a 
front cowling and "a" denotes extensions of the cowling which extend 
laterally of the vehicle body at the front part of the vehicle body. 
Reference character b"denotes fluid cooling radiators which are provided 
within a forward or front opening "c" on forward portions of the 
extensions "a" and "d" denotes rearward openings of the extensions "a" 
through which an air stream introduced from the front opening "a" and 
passing through the radiators "b" is discharged. A pair of air stream 
rectifiers "R" are thus provided as part of the extensions "a", with the 
openings "c" and "d", the radiator "b", a rearward wall "e" and a lower 
wall "f" of the extension "a" as more clearly shown in FIG. 7 serving to 
rectify the air stream flowing along each side of the motorcyle vehicle 
body as will be further explained hereinafter. A relatively wide tire 2 
having a flat tread is mounted on a rear wheel. A round tire A having a 
more conventional tread is mounted on a front wheel. A seat 20 is 
supported between the front and rear wheels. 
The inner construction of the front cowling "A" as shown by FIGS. 1-3 will 
be explained with reference to FIG. 4. In FIG. 4, a front frame 1 and a 
main frame 23 are connected with each other to thereby constitute a 
chassis frame having an upwardly inclined front portion like a chassis 
frame of a conventional motorcyle. 
As shown in FIG. 4, a front wheel 4 is suspended through a wheel axle 5 by 
a steering knuckle 6. Upper and lower swing arms 9 and 10 are each 
respectively connected at one end thereof through pillow ball/joints 7 and 
8 to the upper and lower portions of the steering knuckle 6. The other 
ends of the swing arms 9 and 10 are pivotally connected to the front frame 
1. One end of a steering rod 12 is mounted on the lower portion of the 
upper pillow ball/joint 7 of the knuckle arm 6. The other end of the 
steering rod 12 mounts the lower part of a steering handle or handlebar 11 
which is provided on the front end of the front frame 1. The handlebar 11 
is angularly rotatable in a plane generally parallel to the upper swing 
arm 9 and normal to a plane defined by the steering knuckle 6 and the 
upper and lower swing arms 9 and 10. 
A regulating device 13 is arranged between the upper swing arm 9 and the 
lower swing arm 10, to regulate the upward and downward movement of the 
front vehicle body. One end of the regulating device 13 is mounted on the 
front frame 1 in common with the upper swing arm 9. The other end of the 
regulating device 13 is mounted through a link 14 and a bracket 15 on the 
lower swing arm 10 and connected through the link 14 and a link 16 to a 
bracket 17 of the front frame 1. The regulating device 13 is effective to 
raise or permit upward movement of the front of the vehicle body through 
the common mounting of the upper end of the device with the upper swing 
arm 9 and the links 14 and 16 pivotally connected between the brackets 15 
and 17 which permit upward pivotal movement of the upper and lower swing 
arms 9 and 10 relative to the front frame 1. 
A swingable frame 18 is provided on the upper part of the front frame 1. 
The swingable frame 18 is provided on the front frame 1 along a straight 
line extending between the mounting portions of the upper and lower swing 
arms 9 and 10 to the front frame 1, and is allowed to swing together with 
the front frame 1 about a connecting shaft or axle 1a which connects the 
front frame 1a to the main frame 23. The riding seat 20 and a fuel tank 19 
are arranged and supported on the upper part of the swingable frame 18. 
The main frame 23 has an engine 21, a transmission case 22 and other 
related conventional parts mounted thereon and is joined to the rear 
portion of the front frame 1 coaxially with the connecting shaft 1a of the 
front frame 1. A step or footrest 3 is provided on the lower portion of 
the main frame 23. 
A chain 26 extends between a sprocket 24 provided to the transmission case 
22 and a sprocket 25 disposed on an axle (not shown) for the rear wheel 2. 
Upper and lower swing arms 28 and 29 are each pivoted at one end to the 
transmission case 22. The other ends of the upper and lower swing arms 28 
and 29 are coupled to upper and lower ends of a knuckle arm 27 arranged 
between the sprocket 25 and the axle of the rear wheel 2 and coaxially 
slidable on the rear wheel axle. 
A rear cushion 32 is mounted on the main frame 23 and coupled to the lower 
portion of the lower swing arm 29 through a bracket 30 and a link 31. 
The front cowling "A" of the present invention is mounted to the main frame 
23 by front and rear mounting stays. The front mounting stay "B" for the 
front cowling "A" is coupled to the main frame 23 in a coaxial relation 
with the connecting shaft 1a between the main frame 23 and the front frame 
1 so as to extend adjacent the lower area of the handlebar 11. A rear 
mounting stay "D" for the front cowling "A" is coupled through a bracket 
to the main frame 23 and extends from the main frame 23 to the lower 
portion of the front frame 1 along the inner surface of the front cowling 
"A". 
FIG. 5 shows not only the mounting condition of the front mounting stay "B" 
and the rear mounting stay "D" against the main frame 23 but also the 
mounting condition of the front cowling "A" against the mounting stays "B" 
and "D". As shown in FIGS. 5 and 6, the forward ends of the respective 
mounting stays "B" and "D" project laterally outwardly of the vehicle 
chassis frame to a considerable extent where they fixedly mount the front 
cowling "A" with the lateral ends of the mounting stay "D" secured 
internally of the projected portions or lateral extensions "a" of the 
front cowling "A". 
The operation of a motorcycle incorporating the above described features of 
the present invention, especially during cornering at high speed, will now 
be explained in detail with reference to the drawings. 
In FIG. 4, when the driver shifts his force to the banking direction 
through the handlebar 11 upon cornering in order to bank the vehicle body, 
the force is transmitted through the upper swing arm 9, the steering 
knuckle 6 and the lower swing arm 10 to the front frame 1. The front frame 
1 swings around the connecting shaft 1a between the front frame 1 and the 
main frame 23, so that all of the forward components mounted on the front 
frame 1, such as the front wheel 4, seat 20 and fuel tank 10 are caused to 
bank or swing together with the front frame 1. At this time, a banking 
angle detector (not shown) provided in the regulating device 13 detects 
the banking angle of the front frame 1 thereby causing the front of the 
vehicle body to move upwards, and thus the handlebar 11 is raised up to a 
predetermined level. 
The condition in which only the front frame 1 and those components mounted 
thereon are caused to bank will be explained in detail with reference to 
FIG. 6. 
As shown in FIG. 6, upon cornering, the front wheel is caused to bank 
together with the front frame 1 through the manipulation of the handlebar 
11, by the driver. The main frame 23, however, is prevented from banking 
because the rear wheel tire 2 mounted thereon has a wide flat tire tread 
and also because the force causing the above described forward components 
of the vehicle body to bank is not transmitted to the main frame 23. The 
front frame 1 pivots or swings about the connecting shaft 1a between the 
front frame 1 and the main frame 23 while the main frame 23 remains normal 
to the ground or other surface traversed by the motorcycle. Therefore, 
since each of the mounting stays "B" and "D" are coupled to and supported 
by the main frame 23, they are not banked, and the front cowling "A" and 
lateral extensions "a" of the front cowling "A" are maintained in a 
generally parallel condition relative to the ground. 
The air stream rectifier "R" of the embodiment of the present invention 
shown by FIGS. 1-7 will be explained in detail hereunder with reference to 
FIG. 7. 
As shown in FIG. 7, the air stream entering through the front opening "c" 
of the projected portion or lateral extension "a" in the direction of an 
arrow "E" during running passes through the radiator "b". At this time, 
the heat generated in the engine which is transferred to the radiator by a 
heated cooling fluid is a radiated and cooled by the air stream passing 
through the radiator "b". After passing through the radiator "b" the air 
stream then flows against the upwardly curved rearward wall "e" and is 
discharged out of the rear opening "d" of the air passage in the direction 
of an arrow "F". A reaction force is developed when the air flows against 
the rearward wall "e" and is guided upwards in the direction of the arrow 
"F", which forces the projected extension portions "a" downward as a 
result of the moving air pressure directed against the wall "e". 
As also shown in FIG. 7, an air stream flowing in the direction of an arrow 
"G" is introduced from a narrow space forwardly of the projected portion 
"a" and between the lower wall or bottom surface "f" of the projected 
extension portion "a" and the ground in the direction of the arrow "G" and 
flows outward into a gradually widening space under the rear of the 
projected extension portion "a" as represented by the arrow "H". This air 
flow generates a negative pressure in the space below the lower wall "f" 
thereby cooperating with and enhancing the downward force generated by the 
air stream flowing through the front opening "c" against the internal rear 
wall "e" of the air passage. 
FIGS. 8 through 10 show another embodiment of the present invention, 
wherein the air passage of an air stream rectifier "R" has a rear opening 
"d'" provided through side surface of each extension "a" provided to the 
front cowling "A". Air passing through a radiator "b'" from a front or 
forward opening "c" flows out of the rear opening "d'". An air intake 
opening is provided in the forward face of an air intake scoop "g" mounted 
to the upper surface near the rear end of the lateral extensions "a". The 
air intake opening of the scoop "g" is connected to a second air passage 
in the form of a duct "h" through the extension "a" as shown by FIGS. 8 
and 10, and is provided to positively supply air during running to a 
carburetor or turbocharger of the motorcycle engine fuel delivery system. 
The embodiment of the invention according to the above construction, 
provides an improved suction efficiency to supply air to an engine fuel 
delivery system during running, and stabilizes both sides of the vehicle 
body by providing substantially equal wind pressure developed in the 
nonswingable laterally projecting portions or extensions "a" at both sides 
of the front cowling. 
According to the present invention, a non-swingable front cowling is 
provided to a motorcycle having a swingable front frame and a 
non-swingable rear frame and air stream rectifiers are provided to lateral 
extensions projecting from each side of the front cowling. 
The air stream flowing from forward to rearward of the vehicle body during 
running may be modified by the lateral extensions and the air stream 
rectifiers provided therein to develop a favorable air pressure forcing 
the vehicle body downward toward the ground. Also, other desired 
components like a radiator may be installed in the air passages through 
the extension. Accordingly, the present invention provides a motorcycle 
which permits high speed cornering and more effectively controls the air 
stream at each lateral side of the vehicle body to obtain greater 
stability during running. 
Although preferred embodiments of the invention have been described in 
detail, the present invention is not to be construed as limited to the 
particular forms of the embodiments disclosed herein since the foregoing 
description is to be regarded as illustrative rather than restrictive and 
it should be understood that modifications and variations in the details 
of the construction may be made without departing from the spirit and the 
scope of the invention as defined by the claims appended hereto.