DESC:Field of invention

The present invention relates to a suspension assembly of an automobile and more particularly, to a uni-directional self-aspirated front fork suspension assembly for automobiles such as two wheelers.

Background of the invention

Many types of vehicles utilize one or more suspension assemblies operably positioned between one or more wheels of the vehicle and the body of the vehicle. The suspension assemblies improve operator control by absorbing bumps, or other irregularities, on the surface that the vehicle is traversing. Straddle-type vehicles, such as motorcycles or motor scooters, for example, and other types of vehicles employing a single front wheel often use a telescopic front fork suspension assembly to absorb bumps encountered by the front wheel.

The suspension assemblies/shock absorbers on 2-wheeled vehicles (two-wheeler) are separated into a front fork and a rear cushion. Presently available front fork includes two limbs at the front of the vehicle to steer and provide comfort of ride. The front fork includes fork oil, a piston and springs configured therein. The fork oil and a combination of orifices provide the resistance for ride comfort. However, the front fork of the prior art is prone to leakage on one side thereof that leads to failure of the limb and rubbing noise thereby causing ride discomfort.

Accordingly, there is a need of a front fork for two wheelers that overcomes the above mentioned drawbacks of the prior art.
Objects of the invention

An object of the present invention is to provide friction free operation of two-wheelers by reducing rubbing noise.

Another object of the present invention is to reduce weight on front wheels.

Summary of the invention

Accordingly, the present invention provides a front fork suspension assembly for a vehicle. The front fork includes one limb with fork oil, a piston and springs configured therein and a second limb being uni-directional self-aspirated suspension limb. The second limb comprises an outer tube having open upper end and closed lower end and an inner tube capable of reciprocating within inner diameter of the outer tube. The inner tube comprises a closed upper end and open lower end. The inner tube comprises at least two openings configured in proximity of the lower open end portion, and low-density flexible foam configured on internal circumference thereof. The low-density flexible foam is impregnated with predefined quantity of oil. The inner tube also comprises inert gas filled therein and a non return valve configured at lower open end thereof, wherein the non-return valve allows the inert gas from the outer tube to be back in the inner tube. Wherein upon hitting a bump on a path, the inert gas within the inner tube flows in one direction through the low-density flexible foam and carries micro mist particles of the oil there along through the at least two openings, wherein the micro mist particles of oil get deposited on inner circumference of the outer tube thereby providing lubrication for damping.

Brief description of the drawings

Figure 1 and 2 shows a uni-directional self-aspirated second limb of a front fork assembly, in accordance with the present invention;

Figure 3 shows means for filing inert gas in the uni-directional self-aspirated second limb of the front fork assembly of figure 1; and

Figure 4 shows a non return valve of the uni-directional self-aspirated second limb of the front fork assembly of figure 1.

Detailed description of the invention

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides a front fork suspension assembly for a vehicle, specifically, for a two-wheeled vehicle. The front fork suspension assembly provides a uni-directional self-aspirated (UDSA) front fork. The UDSA front fork of the present invention provides friction free operation of the two-wheelers by reducing friction and thereby reducing the rubbing noise. The UDSA front fork of the present invention being lesser in weight reduces weight on front wheels.

Referring now to figures 1-2, there is shown a front fork suspension assembly (200) for vehicle, especially for two wheeled vehicle. The front fork assembly (200) includes first limb (not shown) with fork oil, a piston and springs configured therein. The first limb is similar to a limb of suspension assembly of the prior art. The front fork suspension assembly (200) further includes a second limb (100) being uni-directional self-aspirated suspension limb. In a preferred embodiment, the first limb is configured on left hand side of the two wheeled vehicle and the second limb (100) (uni-directional self-aspirated suspension limb) is configured on right hand side of the two wheeled vehicle.

The second limb (100) includes an outer tube (10) and an inner tube (50). In an embodiment, the outer tube (10) is made up of aluminium and the inner tube (50) is made of an alloy steel.

The outer tube (10) is fixed to a shaft of the front wheel of two wheeled vehicle. In an embodiment, the outer tube (10) is fixed to the shaft of the two wheeled vehicle by means nut and bolt. In preferred embodiment, the outer tube (10) includes an open upper end (12) and closed lower end (14).

The inner tube (50) is capable of reciprocating within inner diameter of the outer tube (10) through the open upper end (12).Specifically, inner tube (50) reciprocates within the outer tube (10) leaving no gap therebetween. In preferred embodiment, the inner tube (50) includes a closed upper end (52) and open lower end (54).The inner tube (50) is coupled to the handle of the two wheeled vehicle. In an embodiment, the inner tube (10) is fixed to the handle of the two wheeled vehicle by of a bolt.

The inner tube (50) includes at least two openings (26) configured thereon. Further, the inner tube (50) includes low density flexible foam (28) configured on internal circumference thereof. The low density flexible foam (28) is configured such that the foam (28) forms a tube within inner tube (50). In an embodiment, the low density flexible foam (28) is polyurethane foam.

The low density flexible foam (28) is being impregnated with predefined quantity of oil. For example, the quantity of oil may be 30 ml. The oil used for impregnating the low density flexible foam (28) is fork oil generally used within the suspension system.

The inner tube (50) includes inert gas filled therein and a non return valve (30) configured at lower open end of the inner tube (50). In an embodiment, the closed upper end of the inner tube (50) includes means for filling an inert gas therein. As shown in figure 3, the means for filling the inert gas in the inner tube (50) bolt cap assembly (40). The bolt cap assembly (40) includes a bolt cap (42) secured with O-ring (44) and a valve rubber (46). This arrangement provides filling of the inert gas within the inner tube (50) irreversibly.

In preferred embodiment, the inert gas is nitrogen gas. However, it may be evident to those skilled in the art to use other inert gases known in the art.

The non-return valve (30) at the lower open end of the inner tube (50) allows gas from the outer tube (10) to be back in the upper tube (50), if any. As shown in figure 4, the non return valve (30) includes elongated member (32) secured with 0-ring (34) within a housing (36) inside the inner circumference of the inner tube (50). Further, the non-return valve (30) includes a spring (38) wound over the elongated metal part (32). When the inert gas from the inner tube (50) goes into the outer tube (10) during operation of the second limb (100) and when the pressure of the inert gas in the outer tube (10) exceeds the threshold, the elongated member (32) is pushed back by the pressurised inert gas thereby leaving a space between the elongated member (32) and the O-ring (34) and thus allows the inert gas to escape to the inner tube (50). When the inert gas pressure in the outer tube (10) decreases, the spring (38) exerts pressure on the elongated member (32) such that the elongated member (32) is sealed to the inner tube (50) by O-ring (34) restricting escape of the inert gas from the inner tube (50) to the outer tube (10).

During operation, upon hitting a bump on a path, the inert gas within the inner tube (50) flows in one direction through the low density flexible foam (28) and carries micro mist particles of the oil there along through the at least two openings, wherein the micro mist particles of oil get deposited on inner circumference of the outer tube thereby providing lubrication for damping.

Specifically, upon hitting a bump on a path, the inert gas flows in one direction within the second limb (100), while the first limb (150) works normally as per conventional limb of the front fork. The flow of the air in the second limb (100) is proportional to the stroke length and the velocity of displacement (V) of the limb while hitting the bump. While flowing through the second limb (100), the inert gas carries the micro mist oil particles therewith. Here, the low density flexible foam (28) acts as a filter for the inert gas through which the inert gas carries oil mist particles which exits through the at least two openings (26). The micro mist particles of oil get deposited on the on inner circumference of the outer tube (10) thereby providing lubrication for damping.

The second limb (100) also includes a dust sealing assembly (60) provided on uppermost portion of the outer tube (10) for preventing mud and dust accumulation. Further, the second limb (100) oil seal (62) and circlip (64) is provided below the dust seal to prevent leakage of oil if any.
Advantages of the invention

1. The front fork suspension assembly (200) with uni-directional self-aspirated front fork (100) enables friction free operation of the two-wheeler.

2. The front fork suspension assembly with uni-directional self-aspirated front fork (100) is lesser in weight.

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed assembly, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention.

,CLAIMS:We Claim:

1. A front fork suspension assembly for a vehicle, the front fork having one limb with a fork oil, a piston and springs configured therein and a second limb being uni-directional self-aspirated suspension limb, the second limb comprising:
an outer tube having open upper end and closed lower end; and
an inner tube capable of reciprocating within inner diameter of the outer tube, the inner tube having a closed upper end and open lower end , the inner tube having,
at least two openings configured in proximity of the lower open end portion,
low-density flexible foam configured on internal circumference thereof, the low-density flexible foam being impregnated with predefined quantity of oil,
inert gas filled therein; and
a non return valve configured at lower open end of the inner tube, wherein the non-return valve allows the inert gas from the outer tube to be back in the inner tube,
wherein upon hitting a bump on a path, the inert gas within the inner tube flows in one direction through the low-density flexible foam and carries micro mist particles of the oil there along through the at least two openings, wherein the micro mist particles of oil get deposited on inner circumference of the outer tube thereby providing lubrication for damping.

2. The front fork suspension assembly as claimed in claim 1, wherein the upper closed end of the inner tube includes a means for filling an inert gas therein.

3. The front fork suspension assembly as claimed in claim 1, wherein the inert gas is nitrogen gas.

4. The front fork suspension assembly as claimed in claim 1, wherein a dust sealing assembly is provided on uppermost portion of the outer tube for preventing mud and dust accumulation.

5. The front fork suspension assembly as claimed in claim 1, wherein oil seal and circlip is provided below the dust seal to prevent leakage of oil if any.

6. The front fork suspension assembly as claimed in claim 1, wherein the low-density flexible foam is polyurethane foam.