Field of the invention
The present invention relates to "Antilock brake system for Motorcycle" and more particularly this invention relates to mounting of hydraulic electronic control unit or antilock brake system control unit in a typical two wheeled motorcycle having a tubular frame construction.
Background of the invention
Antilock brake system (hereinafter referred to as ABS) in motorcycle prevents locking of the front and rear wheels by automatically regulating the braking force acting on the front and rear wheels at the time of braking operation. The antilock brake system consists of a hydraulic-electronic control unit or antilock brake system control unit ( hereinafter referred to as ABS unit) that controls the brake fluid pressure and a typical disc brake system, which includes master cylinders, connecting hoses and calipers for front and rear.
Various locations are disclosed in the prior art with respect to the mounting of the hydraulic electronic control unit or ABS unit in a two wheeler. In scooter type two wheeled motor vehicle, an ABS unit is normally located in the vicinity of a head pipe at the front end of a vehicle body frame, such as disclosed in US20050134114.This arrangement is determined in consideration with maintaining proper weight distribution between the front and rear of the vehicle body, avoiding an expansion and design constraints of a front cowl associated with the installation of ABS unit, and so on. But it is difficult to secure sufficient space for ABS unit behind the head pipe in a typical motorcycle layout having a tubular frame construction which has a head tube, main tube(s) and down tube(s) and wherein the space between these mentioned tubes are used to locate components like fuel tank assembly, power unit.

transmission unit, battery box, air cleaner case etc. Further, locating the ABS unit behind the head tube of such motorcycle is not technically possible since the space is occupied by the fuel tank assembly. Since in such motorcycles the centre of gravity (CG)lies below the riders' seat, locating the ABS unit away from the CG would result in unstable riding conditions. In another prior art Patent JP2007076555, it discloses a location on the rear side of the main frame of a monocoque structure to locate the ABS Unit., which again makes it difficult to access for servicing, even requires more assembling time. In another patent JP8113179, it discloses a location near the swing arm pivot, since this location is very close to the tyre, there is every chance of dust accumulation in the ABS unit. In all the above mentioned locations the hose lengths are not uniform for front and rear thereby a good brake feel cannot be achieved.
Hence, the objective of the present invention is to locate the ABS unit in a motorcycle having a tubular frame construction having a head tube, main tube(s) and down tube(s), wherein the space between these mentioned tubes are used to locate components like fuel tank, power unit, transmission unit, battery box, air cleaner case etc which overcomes the above mentioned problems associated with the prior art.
Summarv of the invention
An object of the present invention is to substantially overcome the problems or defects or drawbacks encountered in the prior art mentioned above and to adapt an anti lock brake system control unit in a two wheeled a motorcycle having a tubular frame construction with least modifications in comparison to the existing tubular frame construction without having a provision for ABS unit.

Another object of the present invention is to locate the ABS unit near the centre of gravity in order to provide better stability to the vehicle.
Another object of the present invention is to optimize the brake performance by keeping more or less same brake hose length for the front and rear.
Another object of the present invention is to locate the ABS unit in such a way which will render it easy for servicing without the need for removing any near by parts.
Further object of the present invention is to provide an excellent brake feel or brake performance for the rider.
Yet another object of the present invention is to utilize the existing free space available within the vehicle body frame, wherein the ABS unit can be located.
The nature and further characteristic features of the present invention will be made clearer from the following description made with reference to the accompanying drawings.
Brief description of the drawinos
Figure 1 illustrates a conventional two wheeler motorcycle.
Figure 2 is a right side view of the motorcycle according to the first embodiment of the present invention.
Figure 3 is a left side view of the motorcycle according to the first embodiment of the present invention.
Figure 4 is the top view of the motorcycle according to the first embodiment of the present invention.

Figure 5 is the right side view of the frame of the motorcycle according to the second embodiment of the present invention.
Figure 6 is the right side view of the frame of the motorcycle according to the third embodiment of the present invention.
Detailed description of the drawings:
A preferred embodiment of the present invention will be described hereunder with reference to the accompanying drawings.
First, with reference to Figure 1 a motorcycle comprises of a frame (101), front fori< (102) attached to a pivot tube (201) of the vehicle frame, a front wheel (103) attached to these front forks (102), a handle bar (104) connected to the front forks (102), a fuel tank (105) attached so as to straddle an upper part of the vehicle frame, a seat (106) attached to the upper rear portion of the vehicle frame, an engine unit (107) attached to the lower front section of the vehicle frame, a swing arm (108) attached to a lower rear section of the vehicle frame, suspended by a rear shock absorber (not shown) from the vehicle frame and a rear wheel attached to a rear end of swing arm (108). The intake system of the engine comprises of a fuel air metering device such as a carburettor (109), intake duct and an air cleaner. The exhaust system of the engine comprises of exhaust pipe and a muffler. The motorcycle is also provided with a side cover for covering a side section of the vehicle frame, a seat cover for covering a rear section of the vehicle frame below the seat, a front fender (110) for covering an upper part of the front wheel (103), and a rear fender (111) for covering an upper part of the rear wheel (112). The drive from the engine (107) is transmitted from the engine to the driven wheel sprocket mounted on the rear wheel hub mounted on the rear wheel assembly.

As shown in Figure 2, with the side covers open, the body frame of the motorcycle includes a head pipe/ steering pivot/pivot tube (201) at the front end of the body frame. From the top portion of the head pipe (201) one main tube (202) extends backwards and obliquely downwards. Both sides of the lower portion of the main tube is provided with a bracket (203) for rear engine mounting. A tube centre stand (204) is disposed horizontally at the lower portion of the main tube (201), extending outward through an opening on the two sides of the bracket (203).
From the lower portion of the head pipe a pair of left and right down tubes (205) extends obliquely downward and backward, while extending parallel in the direction towards the rear engine mounting bracket (203). The end portion of the said down tubes (205) is welded to the said tube centre stand (204).
From the portion where the main tube starts descending, a pair of upper tubes (206) extends backward and slightly upward towards the rear side of the upper tubes (206) with respect to the horizontal direction.
A pair of side tubes (207) extending from a middle portion of the rear engine bracket (203) and extending backward and upward, while extending parallel in a direction so as to get welded with the end rear portion of the upper tubes (206).
The pair of left and right body frame components such as the down tubes (205) and upper tubes (206) as mentioned above are firmly interconnected with a plurality of horizontal bridges stretching between the pair of pipes and along the width of the vehicle body.

Two reinforcing members (211,212), one between the front end portions of the main tube (202) and down tubes (205) and the other just below the rear end of the upper tubes (206).
The engine assembly comprises engine (214), transmission unit (213) and air fuel metering device / carburettor (109). The engine (214) with the transmission unit
(213) is disposed along the lower side of the vehicle body frame, through the rear engine bracket (203). The hydraulic electronic control unit or ABS unit (215) is placed at the middle portion of the main tube (202) oblique portion with the help of a retaining bracket. The ABS unit (215), the front and rear disc brakes, the master cylinder, brake calliper and brake hose for front and rear constitute a anti lock brake system according to the present invention. The said ABS unit (215) is located in an intermediate position in close proximity to the front of the oblique portion of the main tube (202). The engine (214) with the transmission unit (213) is disposed along the lower side of the vehicle body frame, through the rear engine bracket (203). And both the down and front portion of the ABS unit (215) is surrounded with the engine
(214) and transmission unit (213). Moreover, the space above the top portion of the ABS unit (215) is utilized to locate the fuel tank (216). A battery box (217) is placed behind the said ABS unit (215) in an enclosed space formed by the upper tubes (206), side tubes (207) and oblique portion of main tube(s) (202).
Still furthermore, the brake hoses (not shown in Figure 2) directly from the outlet of the ABS unit (215) run towards the master cylinders and brake calliper front and rear. The brake hose extends backward along the swing amn and is connected to the brake calliper for the rear disc brake. The brake hose extending to the front follow the vehicle body frame and is connected to the front master cylinder and brake calliper.

Referring to Figure 3, which is a left side view of the motorcycle, with side covers open, the ABS unit (215) is placed adjacent to the carburettor (109), making the ABS unit (215) placed offset with respect to the oblique portion of the main tubes (202) near to the CG of the motorcycle. An air cleaner case (301) is placed behind the ABS unit on the right side.
Referring to Figure 4, which is a top view of the motorcycle, with fuel tank removed, the ABS unit (215) is placed little offset towards the right side of the motorcycle body frame.
Locating the ABS unit (215) of the anti lock brake system directly in close proximity to the front of the main tube (202) oblique portion, ensures effective use of free space and provides proper weight distribution between the front and the rear of the vehicle body. By placing the ABS unit (215) in this location ensures almost equal distribution of brake hose length front and rear, thereby optimizing the brake performance. This also provides ease of maintenance of the ABS unit (215).
In another preferred embodiment as shown in Figure 5, the vehicle body frame has only down tube (501) extending from the lower portion of the head tube (502) and one main tube (503) extending from the top portion of the head tube (502). From the top portion of the head pipe (502) the said main tube (503) extends backwards and obliquely downwards. The ABS unit (215) is located in an intermediate position in close proximity to the front of the oblique portion of the main tube (503).And both the down and front portion of the ABS unit (215) is surrounded with the engine (505) and transmission unit (506). Moreover, the space above the top portion of the ABS unit (215) is utilized to locate the fuel tank and air cleaner case.

In another preferred embodiment as shown in Figure 6, the vehicle b.ody frame has one main tube (601) extending from the top portion of the head tube (not shown in the figure) and the said main tube (601) after certain length gets branched into a pair of main tubes (603) extending backwards and obliquely downwards. The ABS unit (215) is located in an intermediate position in close proximity to the front of the oblique portion of the main tubes (603). And both the down and front portion of the ABS unit (215) is surrounded with the engine and transmission unit. Moreover, the space above the top portion of the ABS unit (215) is utilized to locate the fuel tank and air cleaner case.
It is further to be noted that the present invention is not limited to the described embodiment and many other changes and modifications may be made without departing from the scope of the appended claims.

We Claim:
1. A motorcycle provided with an antilock brake system (ABS) having a front fork supporting a front wheel of a motorcycle is supported to be rotatable by a head pipe located at a front end portion of a body frame of the motorcycle, at least one main tube extending from upper portion of the head tube obliquely downward and backward, at least one down tube extending obliquely from lower portion of the head tube towards back and a ABS control unit is disposed in an intermediate oblique portion in close proximity to the front of the main tube, surrounded by the components viz. engine assembly, fuel tank assembly, battery box, air cleaner case, and the said ABS unit is substantially covered by the side cover(s).
2. A motorcycle provided with an antilock brake system as claimed in claim 1 wherein the said engine assembly comprises an engine, a transmission unit and fuel air metering device.
3. A motorcycle provided with an antilock brake system as claimed in claim 1 wherein the said ABS unit Is placed offset from the oblique portion of the main tube due to adjacently placed fuel air metering device.
4. A motorcycle provided with an antilock brake system as claimed in claim 1 wherein the said ABS unit front side Is substantially covered by engine unit.
5. A motorcycle provided with an antilock brake system as claimed in claim 1 wherein the said ABS unit bottom portion is substantially covered by transmission unit.
6. A motorcycle provided with an antilock brake system as claimed In claim 1 wherein the said ABS unit top portion Is substantially covered by fuel tank.

7. A motorcycle provided with an antilock brake system as claimed in claim 1
wherein the said ABS control is a hydraulic electronic control unit.
8. A motorcycle provided with an antilock brake system as claimed in claim 2 wherein the said engine unit is a vertical mounted engine.
9. A motorcycle provided with an antilock brake system as claimed in claim 2 wherein the said engine is a horizontal mounted engine.