Claims:1. An anti-dive front fork suspension (1000) for motor vehicle comprising
an outer tube (100),
an inner tube (110) telescopically slidable within the outer tube (100),
a seat pipe (150) fixed on its one end to the outer tube (100) by a hollow fastening means (130),
a main spring (160) resting on the seat pipe (150) at its one end (163) and on a spacer tube (170) on its other end,
said the spacer tube (170) further interacts with a fork bolt (180) which is affixed onto the inner tube (110),
a brake actuator (290) connected to the electronic control unit (1) and the said electronic control unit (1) is further connected to the front fork suspension (1000) via connecting wire (330),
wherein said seat pipe (150) having a seat pipe internal chamber (210), a damping orifice (190) positioned within said seat pipe internal chamber (210), a spring resting arrangement and, said seat pipe internal chamber (210) having a hollow fastening means (130) placed on an electromechanical actuating means and the hollow fastening means (130) being further attached to an electronic control unit (1) by connecting wire (330).
2. The anti-dive front fork suspension (1000) for motor vehicle as claimed in claim 1, wherein said electromechanical actuating means is an electromechanical valve (250).
3. The anti-dive front fork suspension (1000) for motor vehicle as claimed in claim 1, wherein said electromechanical actuating means is a motor (340)

4. The anti-dive front fork suspension (1000) for motor vehicle as claimed in claim 1, wherein said electromechanical actuating means is positioned above said seat pipe internal piston (240) positioned within the seat pipe internal chamber (210) and is connected to the electronic control unit (1) by the connecting wire (330).
5. The anti-dive front fork suspension (1000) for motor vehicle as claimed in claim 1, wherein said hollow fastening means (130) is a hollow bolt.
6. The anti-dive front fork suspension (1000) for motor vehicle as claimed in claim 1, wherein said spring resting arrangement is a stepped portion (220).
7. The anti-dive front fork suspension (1000) for motor vehicle as claimed in claim 1, wherein the connecting wire (330) is further connected to an anti-lock braking system.
8. The anti-dive front fork suspension (1000) for motor vehicle as claimed in claim 1, wherein the connecting wire (330) is further connected to a combined braking system.
9. A motor vehicle having front fork suspension with anti-dive mechanism as claimed in claim 1.
, Description:FIELD OF INVENTION
The invention relates to front fork suspension utilised in motor vehicles. It more particularly relates to an anti-dive mechanism that can be provided in front fork suspensions of motor vehicle.
BACKGROUND OF THE INVENTION
Modern two-wheelers are equipped with front fork suspension which helps in providing safety to the riders as well as a comfortable ride by acting as a shock absorber. Nevertheless when brake is applied in a vehicle, in order to stop the vehicle, the centre of gravity shifts forward due to the inertia of the vehicle. This causes the vehicle “to nose dive” i.e. the lowering of the front of the vehicle when the moving vehicle is suddenly braked. This effect causes the angle of the rider's body to change and lowers his field of vision momentarily, thereby reducing his driving manoeuvrability and requiring extra attention.
There has been various developments in the prior art to overcome this dive effect while braking. Such mechanisms dealing with diving phenomenon can either be purely mechanical or a combination of electronic and mechanical components.
A low powered two wheeler motor vehicle does not need an anti-dive suspension as the improvements in stability, control and comfort does not justify the added cost. This does not hold true in case of high performance two wheeler motor vehicle where even slight improvement in stability, control and comfort has great overall significance. As of now, cost concerns dictate whether an anti-dive suspension is provided or not.
The prior art JP62191209A discloses an anti-dive mechanism which resists diving by increasing damping force produced during braking. The suspension unit disclosed is functionally linked to the hydraulic braking system. In the said prior art, shock absorber 10 (as shown in Figure 1) is provided with an anti-dive modulator 9 for improving the suspension unit’s anti-dive performance. The bypass passages 20 and 21 connect the dive modulator 9 with the shock absorber 10. During normal operation, oil flow happens from chamber 18 to chamber 19 though both orifice 17a provided on the piston 17 and also through the bypass passages 20 and 21. During braking, the pressure in the chamber 23 increases which causes the valve member 22 to move and come to rest against the valve seat 28, then the oil flows through orifice 17a only. This allows the suspension unit to resist rapid retraction. It may be observed here that the bypass 20 and 21 and the anti-dive modulator 9 add to the bulk of the suspension unit. The anti-dive modulator 9 and the bypasses (20 and 21) being external components are also vulnerable to damage due to external elements. Furthermore, the space constraints on a two wheeler motor vehicle would not allow such an anti-dive mechanism to be provided on it. The disclosed shock absorber 10 hence cannot be readily utilised in two wheeler vehicles. Furthermore, the size and complexity of the suspension unit also add to its overall cost.
Hence, in light of the cited prior art and the limitations cited there is a requirement of an anti-dive front fork suspension which is economical.
Thus the first objective of the present invention is to provide an anti-dive front fork suspension with reduced vulnerability of damage of the anti-dive mechanism.
The second objective of the present invention is to provide an anti-dive front fork suspension which houses the anti-dive mechanism within the front fork suspension itself.
The third objective is to provide an anti-dive front fork suspension which has a simple construction with lesser number of components.
The fourth objective of the present invention is to provide an anti-dive front fork suspension that can be readily utilised in a motor vehicle.
BRIEF DESCRIPTION OF THE INVENTION
In order to achieve the above objective, the present invention provides an anti-dive mechanism with the damping adjustment mechanism in the suspension. On the sudden application of the front brakes, the vehicle’s weight gets transferred to the front axle which thereby results in disturbance of the ride height as well as results in an unstable ride. In the present invention, the electronic control unit is connected with the brake actuator and also the suspension outer tube. On the application of the brake lever, the electronic control unit sends signals to the electromechanical actuating means which is electromechanical valve (in one embodiment) or to the motor (in second embodiment of the present invention). This control unit adjusts the electromechanical valve (as in first embodiment) or the motor (as in the second embodiment) which is positioned over the seat pipe internal piston. This action thereby controls the opening and closing of the damping orifice and thus the damping rate of the front fork suspension is controlled in case of diving situation.
Thus the stability of the vehicle is maintained and also this results in anti-dive condition in the suspension. The anti-dive mechanism being situated within the front fork suspension is of simple and compact construction, with reduced number of components and reduced vulnerability of damage due to external elements. It can be readily utilised in a two wheeler motor vehicles.
Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiment contained therein.
BRIEF DESCRIPTION OF DIAGRAMS
Other aspects of the invention will become apparent by consideration of the accompanying drawings and their description stated below, which are merely illustrative of a preferred embodiment of the invention and do not limit in any way the nature and scope of the invention.
Figure 1 illustrates the outer view of the anti-dive front fork suspension according to the present invention.
Figure 2 illustrates a cross sectional view of the anti-dive front fork suspension according to the first embodiment of the present invention.
Figure 3 illustrates the magnified cross sectional view of the anti-dive mechanism according to the first embodiment of the present invention.
Figure 4 illustrates the magnified cross sectional view of the anti-dive mechanism according to the second embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described with reference to the accompanying drawings which do not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.
According to Figure 1, the anti-dive front fork suspension (1000) for a motor vehicle as per one of the embodiments of the present invention comprises of an outer tube (100), an inner tube (110) telescopically slidable within the outer tube (100). Other components conventionally forming part of a front fork suspension namely, a seat pipe (150), a main spring (160) resting on the seat pipe (150). The actuation of the brake lever (290) sends signal to the electronic control unit (1) which thereby controls the movement of the electromechanical actuating unit which is electromechanical valve (according to the first embodiment) or the motor (according to the second embodiment) which again controls the motion of the seat pipe internal piston (240) and thus controlling the opening and closing of the damping orifice (190).
Figure 2 according to the illustrative embodiment is the cross sectional view of suspension system (1000) with the complete damper adjustment mechanism. The electromechanical actuating unit is placed on the seat pipe internal piston (240). The piston has an ‘O’-ring (260) which rests on the groove of the piston. The electromechanical actuating unit is connected to the electronic control unit (1) by the connecting wires (330 as in figure 3). When the vehicle hits a bump the main spring (160) compresses and absorbs the energy of the impact. As the main spring (160) compresses, the damping fluid flows into the seat pipe (150) through a damping orifice (190 as shown in figure 3). The damping fluid then flows out of the opening at the other end of the seat pipe (150) (the seat pipe (150) being hollow and open at its other end). The flow of damping fluid through the orifice (190) produces the required compression damping. When the vehicle returns to level surface allowing the main spring (160) to expand, the flow of damping fluid is reversed. During compression of the main spring (160), some amount of damping fluid also flows through the gap between the seat pipe (150) and inner tube (110) via a valve (provided in said gap), into a chamber formed between the seat pipe (150) and the inner tube (110). The valve (provided in said gap) present between the inner tube (110) and the seat pipe (150) prevents backflow of the damping fluid through the gap between the seat pipe (150) and the inner tube (110). Therefore when the main spring (160) expands, only the damping orifice (200) allows the damping fluid to flow out of the chamber formed in between the seat pipe (150) and the inner tube (110). The net result is that uncontrolled oscillation of the front fork suspension is avoided. The functioning of other components (like the rebound spring, seals and washers) is similar to those provided in a conventional front forks as known in the art.
Figure 3 illustrates the enlarged view of the anti-dive mechanism as per the current invention indicated by dotted portion (500) in Figure 2 as per the first embodiment of the invention (500A) having the electromechanical actuating unit which is an electromechanical valve (250) as the damping adjustment unit. The anti-dive mechanism provided comprises of the seat pipe (150) having the seat pipe internal chamber (210), the seat pipe internal piston (240), the seat pipe internal spring (270), the hollow connecting means which is a hollow bolt (130) and electromechanical valve (250) which is connected to the electronic control unit (1) with the connecting wires (330). A damping orifice (190) is positioned within the seat pipe internal chamber (210). The damping orifice (200) is provided on the seat pipe (150) close to the end of the seat pipe (150) on which the main spring (160) rests. The seat pipe internal piston (240) is provided with an O-ring (260) in the groove. The seat pipe internal piston (240) interacts with the spring resting arrangement which is a stepped portion (220) via a seat pipe internal spring (270). Upon operation of a brake actuator (290 shown in figure 1) by the rider, the electronic control unit (1) sends signal to the electromechanical valve (250). This electromechanical valve (250) thereby pushes the seat pipe internal piston (240) with the plunger (320) of electromechanical valve (250). Hence the seat pipe internal piston (240) experiences a force which causes it to compress and retract towards the stepped portion (220). The seat pipe internal piston (240) while retracting covers the damping orifice (190) partially causing the damping force produced to increase, thus controlling the dive. When the rider ceases to operate the brake actuator (290) the electronic control unit (1) again sends signal which causes the electromechanical valve (250) to return back to its original position. With the force no longer acting over the seat pipe internal piston (240), the seat pipe internal piston (240) returns to its original position under the action of the seat pipe internal spring (270) and the retraction of the electromechanical valve (250). This causes the damping orifice (190) to be uncovered. The change in damping setting hence lasts as long as the rider continues to operate the brake actuator. This insulates the braking system from any pressure oscillations due to vehicle hitting a big road surface irregularity.
Figure 4 illustrates the enlarged view of the anti-dive mechanism as per the current invention indicated by dotted portion (500) in Figure 2 as per the second embodiment of the invention (500B) having the electromechanical actuating means which is a motor (340) as the damping adjustment unit. The anti-dive mechanism provided comprises of the seat pipe (150) having the seat pipe internal chamber (210), the seat pipe internal piston (240), the seat pipe internal spring (270), the hollow fastening means which is a hollow bolt (130) and a motor (340) which is connected to the electronic control unit (1) with the connecting wires (330). A damping orifice (190) is positioned within the seat pipe internal chamber (210). The damping orifice (200) is provided on the seat pipe (150) close to the end of the seat pipe (150) on which the main spring (160) rests. The seat pipe internal piston (240) is provided with an O-ring (260) in the groove. The seat pipe internal piston (240) interacts with the stepped portion (220) via a seat pipe internal spring (270). Upon operation of a brake actuator (290 shown in figure 1) by the rider, the electronic control unit (1) sends signal to the motor (340) which is positioned on the slit of the retainer socket (350) which is threadedly placed over a locking bush (360). This arrangement thereby pushes the seat pipe internal piston (240) which hence experiences a force which causes it to compress the seat pipe internal spring (270) and retract towards the stepped portion (220). The seat pipe internal piston (240) while retracting covers the damping orifice (190) partially causing the damping force produced to increase, thus controlling the dive. When the rider ceases to operate the brake actuator (290) the electronic control unit (1) again sends signal which causes the motor (340) to return back to its original position. With the force no longer acting over the seat pipe internal piston (240), the seat pipe internal piston (240) returns to its original position under the action of the seat pipe internal spring (270) and the reverse rotation of the motor (340). This causes the damping orifice (190) to be uncovered. The change in damping setting hence lasts as long as the rider continues to operate the brake actuator. This insulates the braking system from any pressure oscillations due to vehicle hitting a big road surface irregularity.
While it is stated that the anti-dive front fork (1000) is electronically connected by brake actuator to front wheel circuit or rear wheel circuit or both. The stated pathway can be altered to be electronically connected with an Anti-lock Braking System (ABS) or a Combined Braking System (CBS) as well. Any modification carried out to the anti-dive front fork (1000) to allow such connection to be made lie within the scope of the invention.
The technical advancements offered by the present disclosure include:
• The present invention results in reduced diving mechanism on sudden application of brakes.
• Shorter braking distance can be achieved by the present invention as the front brake resists the weight of the vehicle being pushed onto the front wheel.
• The front suspension can be adjusted without being set-up to resist compression when the front brake is applied.
• Due to the damping adjustment mechanism on application of the front brake, the unevenness of the road is encountered.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

List of reference numbers
1-Electronic Control Unit
100-Outer Tube
110-Inner Tube
130-Hollow Fastening Means
150-Seat Pipe
160-Main Spring
170-Spacer Tube
180-Fork Bolt
190, 200-Damping Orifice
210-Seat Pipe Internal Chamber
220-Stepped Portion
240-Seat Pipe Internal Piston
250-Electromechanical Valve
260-O-ring
270-Seat Pipe Internal Spring
290-Brake Actuator
320-Plunger of Electromechanical Valve
330-Connecting wire to ECU
340-Motor
350-Retainer Socket
360-Locking Bush
500-Outer tube portion with damping adjuster
500A-Outer tube portion with Electromechanical Valve
500B-Outer tube portion with Motor
1000-Anti-dive Front Fork