DESC:FRONT FORK ASSEMBLY FOR CONTROLLING DAMPING FORCE
Field of the invention
The present invention relates to a front fork assembly of an automobile and more particularly, to a front fork assembly with leak proof arrangement for controlling damping force for superior ride handling.
Background of the invention
The typical motorcycle has a pair of fork tubes for the front suspension. Front fork serves as rigidity component just like a frame. The front fork maintains proper damping through traction with the road surface. Front suspension of two wheelers bears a direct relationship with damping force. Normally front forks are configured with a steel chrome plated inner tube sliding inside an outer tube made of aluminium, a spring and a piston. Holes on the piston are the major contributor for controlling both rebound and compression damping force of front fork. These holes are in the range of 1 mm to 1.5 mm depending on the required damping. The functional accuracy depends on the precision of holes. There are very minimal options of varying or tuning damping force to the vehicle requirement. Original conventional design does not allow providing controlled damping force at different velocities. This is one of the major draw-back of the conventional design which fails to provide tuning options of damping force. Secondly, the oil leakage happens due to exposed inner tube surface. The inner tube provides a guide surface and also acts as damping chamber. To keep the pace of technology development, it is necessary to build suspension with better controllability on the damping force, leak proof front fork design which provides an extended life and superior front suspension for two / three wheeler vehicles.
Accordingly, there exists need to provide a front fork assembly for superior damping force control, that overcomes the above mentioned drawbacks in the prior art.
Object of the invention
An object of the present invention is to provide enhanced controllability of damping force in front forks at different velocities for superior ride handling and safe ride of the user.
Another object of the present invention is to provide leak proof front fork design with an extended product life.
Yet, another object of the present invention is to provide a superior front suspension for two / three wheeler vehicles.
Summary of the invention
Accordingly, the present invention provides a front fork assembly (100) for controlling damping force consisting of an outer tube connected to the wheel hub of vehicle; an inner tube having one end slidingly received in the outer tube and other end connected to the handle means. The inner tube sealed at both the ends with sealing means is embedded with an oil chamber and a gas chamber separated by a floating piston. One end of the inner tube is sealed with oil seal that prevents the fluid in the oil chamber from entering into the outer tube. Other end of the inner tube is sealed with a bolt cap provided with gas filling port. A piston valve unit reciprocating within the oil chamber is operably connected to the outer tube through a solid piston rod, wherein the piston valve unit consists of plate valves and a piston with piston holes configured thereon, designed for controlling the oil flow there through. A floating piston is operably connected to the piston valve unit through a helical spring. The floating piston moves to and fro depending on the pressure difference between oil and gas chambers. A foam soaked in oil is housed inside the outer tube for lubricating the sliding surfaces of the inner tube and the outer tube. The plate valves and piston holes are designed for controlling the oil flow for fulfilling vehicle ride comfort requirement.
As the damping arrangement is inbuilt in the inner tube, oil does not enter the sliding portion inside the assembly. This prevents the failure of inner tube due to oil leak.
Brief description of the drawings
The objectives and advantages of the present invention will become apparent from the following description read in accordance with the accompanying drawings wherein,
Figure 1 shows across sectional view of a front fork assembly for superior damping force control, in accordance with the present invention.; and
Figure 2 shows detailed cross sectional view of a front fork assembly for superior damping force control, in accordance with the present invention.
Detail 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 assembly for superior damping force control at different velocities. The cartridge front fork assembly achieves confirmed controllability in damping force with a superior life and ride handling. The present invention provides leak proof front fork design for superior front suspension for two / three wheeler vehicles. This also increases the endurance of inner tube of front forks system by eliminating failure due to oil leak.
This present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. The components of the invention and the reference numbers are also listed in the table below:
Ref. No Description Ref. No Description
100 Front fork assembly 36 Helical spring
10 Outer tube 38 Spacer
12 Foam 40 Gas chamber
14 Strut base Screw 42 Gas filling port
16 Bore 44 Floating piston
20 Inner tube 46 Bolt cap
30 Oil chamber 50 Piston valve unit
32 Oil seal 52 Piston Rod
34 Rod guide
FIGS. 1 and 2 illustrate a front fork assembly (100) for controlling damping force, (hereinafter “the assembly (100)”), in accordance with the present invention is shown.
The assembly (100) is constructed to be incorporated between vehicle body and the wheel hub. The assembly (100) consists of an outer tube (10) connected to the wheel hub and an inner tube (20) slidingly received therein, with other end of the inner tube (20) connected to the vehicle handle means. The inner tube (20) is embedded with an oil chamber (30) and a gas chamber (40) therein, separated by a floating piston (36). One end of the inner tube (20) inside the outer tube (10) is concealed with an oil seal (34) and the other end outside the outer tube (10) is concealed with a bolt cap (46) provided with a gas filling port (42). The oil seal (32) prevents damping fluid entering into the outer tube (10).
A piston valve unit (50) slidingly received within the oil chamber (30) is operably connected to the outer tube (10) through a solid piston rod (52). The piston valve unit (50) is configured with plate valves and a piston. The reciprocating movement of piston rod (52) within the inner tube (20) is guided by a rod guide (34) fitted near the oil seal (32).
The floating piston (44) is operably connected to the piston valve unit (50) through a helical spring (36) and a spacer (38). Floating piston (44) moves to and fro depending on the pressure difference between oil and gas chambers. During fork compression stroke, oil force will push the floating piston (44) and apply pressure against gas chamber (40). During normal condition, gas pressure will be pushing the floating piston (44) keeping fork in extended condition.
A foam (12) soaked in oil is housed inside the outer tube (10) for lubricating the sliding surfaces of the inner tube (20) and the outer tube (10). In the piston valve unit (50), the plate valves and piston holes are designed for controlling the oil flow as per the vehicle ride comfort requirement. The damping is controlled with a plate valve design which can resist the oil flow with precision and repeatability. During functioning of the assembly (100), the inner tube (20) moves to and fro, oil passes thru piston valve unit (50) and provides damping (tuned resistance to oil flow). In addition to piston valve unit (50), the gas filling port (42) helps in avoiding the lagging action during changeovers of fork action.
Thus the assembly (100) provided with damping control arrangement shifted to the inner tube (20) provides enhanced controllability of damping force in front forks at different velocities for superior ride handling and safe ride of the user. Inner tube 20) acts as a concealed damper cartridge providing low friction movement and leak less front fork. Further, the suspension system (100) of the present invention may be used on motorcycles as well as other handlebar-steered vehicles.
Advantages of the invention
1. The system (100) provides enhanced controllability of damping force in front forks at different velocities for superior ride handling and safe ride of the user.
2. In the present system (100), damping control mechanism is shifted to inner tube by eliminating the forged piston with holes.
3. Another advantage of the system (100) is to increase the endurance of inner tube (20) in telescopic front forks system by eliminating failure due to oil leak and oil seal damage.
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 system, 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 scope of the invention.

,CLAIMS:CLAIMS
We claim:
1. A front fork assembly (100) for controlling damping force consisting of:
an outer tube (10) connected to the wheel hub of vehicle;
an inner tube (20) having one end slidingly received in the outer tube (10) and other end connected to the vehicle handle means, the inner tube (20) embedded with an oil chamber (30) and a gas chamber (40) separated by a floating piston (36), and sealed at both the ends with sealing means;
a piston valve unit (50) operably connected to the outer tube (10) through a solid piston rod (52) and reciprocating within the oil chamber (30), wherein the piston valve unit (50) consists of plate valves and a piston with piston holes configured thereon, designed for controlling the oil flow there through;
a floating piston (44) operably connected to the piston valve unit (50) through a helical spring (36), moving to and fro depending on the pressure difference between oil and gas chambers; and
a foam (12) soaked in oil housed inside the outer tube (10) for lubricating the sliding surfaces of the inner tube (20) and the outer tube (10);
wherein the plate valves and piston holes are designed for controlling the oil flow for fulfilling vehicle ride comfort requirement.
2. The front fork assembly (100) as claimed in claim 1, wherein sealing means is an oil seal (34) preventing fluid in the oil chamber (30) from entering into the outer tube (10).
3. The front fork assembly (100) as claimed in claim 1, wherein the sealing means is a bolt cap (46) provided with a gas filling port (42).
4. The front fork assembly (100) as claimed in claim 1, wherein the reciprocating movement of piston rod (52) within the inner tube (20) is guided by a rod guide (34) fitted near the oil seal (32).
Dated this 22nd day of January, 2018
Prafulla Wange
(Agent of Applicant),
(IN/PA-2058)