DESC:FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

TITLE OF THE INVENTION
“DAMPING CONTROL SYSTEM FOR SUSPENSION OF A MOTOR VEHICLE”

Endurance Technologies Limited
E-92, M.I.D.C. Industrial Area, Waluj,
Aurangabad – 431136, Maharashtra, India

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed.

Field of Invention

[001] The invention relates to shock absorber of motor vehicle. It more particularly relates to shock absorber having damping control / adjustment system that operates automatically based on sensed change in position of the spring preload adjuster that is considered in relation with input provided by the motor vehicle user.

Background of the Invention

[002] Conventionally available shock absorbers/suspensions are provided with independent mechanisms for adjusting preload of their main spring and the damping force provided by the valves/orifices/pistons. It is essential for shock absorbers to obtain a damping force that appropriately balances against the preload adjustment provided to the main spring. This is necessary because improperly adjusted preload and damping can make the vehicle unstable and very hard to handle safely at any given operating speed. Motor vehicle users are therefore always advised against attempting to perform these changes (damping force settings and preload settings) on their own. Using expert assistance for performing these changes not only reduces the chances of accidents, but also lead to increase the time and money required for correctly setting up a motor vehicle for use on different road surfaces. As such need of ensuring rider safety and comfort in different circumstances adds to motor vehicle operation and maintenance costs.

[003] The available mechanisms which may be provided on the shock absorbers for performing such tasks experience great deal of vibrations and negative effects resulting from there interaction with natural elements. Therefore, ensuring their continued reliable performance is a problem in itself. Adding redundancies to enhance reliability of these mechanisms increases the number of sensors, the size, the weight and the processor requirement of the suspension unit. Adding redundancies also make them very complex and therefore hard to manufacture and install on a small motor vehicle. Providing reliable performance while reducing overall size and complexity of such a shock absorber/suspension is therefore a technical challenge which also has cost implication.

[004] Given the normal installation position and orientation of shock absorbers on motor vehicles, users may with tools available to them, adjust the spring preload themselves. As such there exists a need of providing a damping control system for shock absorbers/suspensions enabling partial automation of the task of adjusting damping when the parameter of spring preload is adjusted manually by utilizing the least number of electronic components mounted on the shock absorber while enhancing the comfort and long term performance and reliability of the system.

Objectives of the Invention

[005] The main objective of the present invention is to provide a damping control system for shock absorber/suspension with a simple, compact and accurate sensing mechanism for sensing change in spring preload settings.

[006] Another object of the present invention is to provide a damping control system for a shock absorber/suspension that can accurately adjust damping based on the sensed change in spring preload settings and user given input.

[007] Yet another objective of the present invention is to provide a damping control system for a shock absorber that enhances rider comfort while ensuring rider safety.

[008] Still the objective of the present invention is to provide a shock absorber with automatic damping control system providing long term performance reliability.

Brief Description of Drawings

[009] This invention is illustrated in the accompanying drawings, throughout which like reference letters / numerals indicate corresponding parts in the various figures. The embodiments herein and advantages thereof will be better understood from the following description when read with reference to the following drawings, wherein
Figure 1a discloses the schematic view of the damping control system linked to a suspension unit of a motor vehicle in accordance with an embodiment of the present invention.
Figure 1b shows a cut sectional view of the suspension unit shown in Fig. 1a along a plane in which the attached gas canister is made visible.
Figure 2 shows perspective view of the lower sub-assembly of the suspension unit shown in Fig. 1a wherein the components of damping control system for sensing the change in preload of the spring are mounted in accordance with an embodiment of the present invention.
Figure 3 presents an exploded view of the lower sub-assembly of the suspension unit disclosed in Fig. 2.
Figures 4a, 4b and 4c show top view, cut sectional view and bottom view of the cylindrical piece forming a single integral structure with the spring preload adjustment ring as per the present invention.
Figure 5 presents perspective view of a suspension unit in accordance with second embodiment of the present invention.
Figure 6 shows the cut sectional view of the suspension unit disclosed in Fig. 5.
Figure 7 shows an exploded view of a sub-assembly of the suspension unit, with the components for sensing change in preload of the spring, as disclosed in Fig. 5 and 6.
Figure 8 presents perspective view of a suspension unit in accordance with third embodiment of the present invention.
Figure 9 shows the cut sectional view of the suspension unit disclosed in Fig. 8.
Figure 10 shows an exploded view of a sub-assembly of the suspension unit, with the components for sensing change in preload of the spring, as disclosed in Figs. 8 and 9.
Figure 11 presents perspective view of a suspension unit in accordance with fourth embodiment of the present invention.
Figure 12 shows magnified view of lower portion of suspension unit as shown in Fig. 11.
Figure 13a presents cut sectional view of the suspension unit as disclosed in Fig. 11 along a plane in which the actuation mechanism is visible.
Figure 13b shows another cut sectional view of the suspension unit as disclosed in Fig. 11 along a plane in which the gas canister is visible.
Figure 14 shows an exploded view of the lower sub-assembly of the suspension unit with the components for sensing change in preload of the spring as disclosed in Figs. 11-12.

Detailed Description of the Present Invention

[0010] Referring to Fig. 1a, a damping control system for a shock absorber/suspension of a motor vehicles comprises of at least a preload adjustment assembly (50), an electronic control unit (ECU) (52), a sensor (42), an actuation mechanism (10), a communication module (44) and a suspension unit (60). The preload adjustment assembly (50) itself comprises of a spring preload adjustment ring (30), a cylindrical piece (32), a hollow cylindrical cap (34), a magnet (36), a bracket (40) and a sensor (42). The preload adjustment assembly (50) is mounted below the spring(s) provided on the suspension unit (60). The preload adjustment assembly (50) is in communication with the ECU (52) through the communication module (44). The actuating mechanism (10) is fitted on a bracket (12) of the suspension unit (60) and is in continuous communication with the ECU (52) through the communication module (44). The ECU (52) is mounted suitably inside the vehicle in proximity of the sensor (42) and is configured to control the damping characteristics through the actuating mechanism (10) in response to the change in preload of main springs (18, 24). The extent of operation of the actuation mechanism (10) by the ECU (52) depends upon input given through the switch (52B) by the user/rider.

[0011] Referring to Figs. 2, 3, 6, 7, 9 and 10, the cylindrical piece (32), forming a single integral structure with the spring preload adjustment ring (30) at its upper end and the hollow cylindrical cap (34) at its lower end, is rotatably mounted below the main springs (18, 24) so as to be concentric with the outer tube (20). The profiled lower surface of the cylindrical piece (32) is located on the curved top surface of the projection (41P1) given on the outer curved surface of a bracket (41) of the outer tube (20). The magnet (36) is mounted on the outer flat surface of the projection (41P1) given on the bracket (41) of the outer tube (20) such that the hollow cylindrical cap (34) cuts the communication (i.e. the magnetic flux intensity) between the magnet (36) & the sensor (42) (the sensor (42) is working as a receiver). The sensor (42) is mounted on an inner surface of a profiled bracket (40). The bracket (40) is attached in alignment with the projection (41P1) given on the bracket (41) using suitable fastening means selected from welding, conventional fastening means, interlocking grooves arrangement and snap fit lock arrangement (refer Figs. 3, 7 and 10).

[0012] Alternatively, in the embodiments of the invention as shown in Figs. 8, 9, 10, 11, 13a and 14, the cylindrical piece (32) forms a single integral structure with the hollow cylindrical cap (34) located concentrically with it. The spring preload adjustment ring (30) is located at a level horizontal plane of the hollow cylindrical cap (34) and forms a single integral structure with the hollow cylindrical cap (34). The adjustment ring (30), the cylindrical piece (32) and the hollow cylindrical cap (34) are rotatably mounted below the main springs (18, 24) so as to be concentric with the outer tube (20), a washer (26) and/or spring seat (S3) is(are) located between the main spring (24) and the hollow cylindrical cap (34). The cylindrical piece (32) is configured so as to interact with the outer curved surface of the outer tube (20). The cylindrical piece (32) may interact with the outer curved surface of the outer tube (20) via matching threads given on the cylindrical piece (32) and the outer tube (20), in which case the lower surface of the cylindrical piece (32) will have a flat profile (refer Fig. 13a). In this case main spring’s preload adjustment would be caused by movement of the cylindrical piece (32) over the matching threads given over the outer tube (20) only when the adjustment ring (30) is rotated using a tool. The cylindrical piece (32) can also be configured to slide over the curved outer surface of the outer tube (20), in which case the lower surface of the cylindrical piece (32) would be profiled so as to cause main spring’s preload adjustment when it slides over the projection (41P1), which would happen only when the adjustment ring (30) is rotated using a tool. The lower surface of the cylindrical piece (32) is in both of these cases going to be located above the projection (41P1). The magnet (36) is mounted on inside flat surface of one leg of the bracket (40U) and the sensor (42) is mounted on inside flat surface of the other leg of the bracket (40U) in such way that the hollow cylindrical cap (34) cuts communication (i.e. magnetic flux intensity) between the magnet (36) (working as transmitter) and the sensor (42) (receiver).

[0013] The sensor (42) is in communication with the ECU (52) by the communication module (44). The actuation mechanism (10) is mounted on the bracket (12) of the suspension unit (60) using a bolt. The actuation mechanism (10) is in continuous communication with the ECU (52) through the communication module (44). The ECU (52) is mounted inside the vehicle in close proximity of the sensor (42). The ECU (52) is configured to control the damping characteristics automatically through the actuation mechanism (10) in response to the change in preload of the main spring(s) (18, 24) sensed by the sensor (42). The extent of operation of the actuation mechanism (10) by the ECU (52) depends upon input given through the switch (52B) by the user/rider.

[0014] The shaft of the actuation mechanism (10) is rigidly fixed to a screw (12S) inside the bracket (12) of the suspension unit (60), making positive and continuous communication with the said screw (12S). This is done to prevent occurrence of slipping between these components. The communication module (44) is selected from a group wired communication (wiring harness) and wireless communication or combination of thereof. The actuation mechanism (10) of the damping control system (100) is selected from a set of hydraulic actuator, pneumatic actuator, electro-magnetic mechanism. The choice of the type of mechanism is made depending upon the actuation force required as well as the space available for attaching said actuation mechanism (10) on the bracket (12). In any case, care is taken to configure the actuation mechanism (10) in such a manner that its input is transmitted via a shaft linked to the screw (12S), without slippage. The damping control system (100) is provided with a switch (52S) and a battery (52B) and said switch (52S) and said battery (52B) are in communication with the ECU (52) through the communication module (44). The sensor (42) of the damping control system (100) is preferably a Hall Effect sensor.

[0015] The switch (52S) when operated, alters the selection of reference/lookup table in the ECU (52) thereby altering the extent of operation of the actuation mechanism (10) for lowering/lifting the damping pin (11) within the piston rod (16), when the data received from the sensor (42) changes. As such, when the data received from the sensor (42) changes, the ECU (52) causes a(an) decrease/increase in the dimensions of the opening formed at the lower end of the damping pin (11) located on the central opening of the intermediate hollow cylindrical part (17), causing an increase/decrease in the damping force values. This is true for all the disclosed embodiments of the damping control system.

[0016] The suspension unit (60) in accordance with the first embodiment of the invention, as shown in Figs. 1a to 4c, comprises of brackets (12 & 41), main spring (18 & 24), an outer tube (20), spring seats (S1, S2 and S3), a canister (41GC), a base valve assembly (20BVA), a rebound spring (25), a piston rod (16), a guiding and sealing assembly (20GSA), a bump rubber (16BR). The piston rod (16) has a hollow cylindrical shape with its one end fitted within the mounting bracket (12). An intermediate hollow cylindrical part (17) is fitted and partially located within the other end of the piston rod (16). The intermediate hollow cylindrical part (17) has a lower cylindrical portion for locating and fixing the piston (19) and the piston (19) is positioned within the outer tube (20). A nut (17S) holds the piston (19) in its position on a lower cylindrical portion of the intermediate hollow cylindrical part (17). The orifice(s) (22) provided on the curved cylindrical surface of the piston rod (16) and the hollow central portion of the piston rod (16) together form a continuous passage for damping fluid with the central opening of the intermediate hollow cylindrical part (17). A set of ribs (16R) and O-rings (16O) are provided on the damping pin (11) above the location of the orifice(s) (22) to prevent any flow of damping fluid above their postion within the suspension unit (60). The rebound spring (25) is located between an annular rib given on the intermediate hollow cylindrical part (17) and the lower surface of the lower guide (G1).

[0017] The main spring (18) is located between the spring seat (S1) given on the bracket (12) and the spring seat (S2) given on the outer tube (20). The main spring (24) is located between lower end of the spring seat (S2) given on the outer tube (20) and a washer (26) located on the spring seat (S3) which itself is positioned on the upper surface of the spring preload adjustment ring (30) of the bracket (41) (refer Fig. 1a). The spring seat (S2) can slide up/down over the curved outer surface of the outer tube (20) when preload of the main springs (18, 24) is adjusted by rotating the spring preload adjustment ring (30) with a tool. The outer tube (20) is fixed within the open cylindrical portion of the bracket (41), the inner tube (21) is fixed concentrically with the outer tube (20) within the open cylindrical portion of the bracket (41). The canister (41GC) is fitted on lower end of the bracket (41) and is connected by a passage (41PA) to lower end of the open cylindrical portion of the bracket (41). The base valve assembly (20BVA) is mounted at the base of the open cylindrical portion of the bracket (41) and located within the inner tube (21), a passage given in the bracket (41) below the base valve assembly (20BVA) connects the space given below the base valve assembly (20BVA) and the space between the inner tube (21) and outer tube (20).

[0018] The guiding and sealing assembly (20GSA) has, a lower guide (G1) having surfaces resting on both the upper surface of inner tube (21) and inner curved surface of the outer tube (20), an upper guide (G2) having sealing lips that is located resting above the lower guide (G1) and has a curved surfaces resting on inner curved surface of the outer tube (20), and a top cap (20TC) located above the upper guide (G2) and fixed to the open end of the outer tube (20). The guiding sealing assembly (20GSA) has a central opening to allow the piston rod (16) to reciprocate (refer Figs. 1a and 1b). The damping pin (11) is located inside the hollow cylindrical portion of the piston rod (16) above the intermediate hollow cylindrical part (17). The screw (12S) is located above the damping pin (11) and within a hollow space within the bracket (12). The bump rubber (16BR) is located on the piston rod (16) between the top cap (20TC) and a flat fixing nut (12FN) given below the spring seat (S1) on the piston rod (16). The suspension unit (60) excluding the main springs (18 & 24) can be stated to be constituting a functional damping unit. Said damping unit can be selected from a hydraulic damper, emulsion damper, and gas filled damper.

[0019] In the second embodiment of the invention, as shown in Figs. 5, 6 and 7, the details pertaining to inter relation/association/connections between the preload adjustment assembly (50), the ECU (52), the battery (52B), the switch (52S), the sensor (42), the actuation mechanism (10), the communication medium (44) and suspension unit (60) remain the same as that shown in Fig. 1a and as detailed for the first embodiment. The suspension unit (60) of the second embodiment specifically comprises of brackets (12 & 41), a main spring (18), an outer tube (20), spring seats (S1 and S3), a piston rod (16), a guiding and sealing assembly (20GSA) and a bump rubber (16BR).

[0020] The piston rod (16) has a hollow cylindrical shape with its one end fitted within the mounting bracket (12). An intermediate hollow cylindrical part (17) is fitted and partially located within the other end of the piston rod (16). The intermediate hollow cylindrical part (17) has a lower cylindrical portion for locating and fixing the piston (19), and the piston (19) is positioned concentrically and movably within the outer tube (20). A nut (17S) holds the piston (19) in its position on a lower cylindrical portion of the intermediate hollow cylindrical part (17). The orifice(s) (22) provided on the curved cylindrical surface of the piston rod (16) and the hollow central portion of the piston rod (16) together form a continuous passage for damping fluid with the central opening of the intermediate hollow cylindrical part (17). A set of ribs (16R) and O-rings (16O) are provided on the damping pin (11) above the location of the orifice(s) (22) to prevent any flow of damping fluid above their postion within the suspension unit (60). The intermediate hollow cylindrical part (17) is provided with an annular rib and said annular rib rests on the lower surface of the lower guide (G1).

[0021] The main spring (18) is located between the spring seat (S1) given on the bracket (12) and the spring seat (S3) given on the outer tube (20), the spring seat (S3) itself is positioned on the upper surface of the spring preload adjustment ring (30) of the bracket (41). A cover (14) having an in general cylindrical shape and a ring shaped support surface at its one end is also provided in this embodiment. The ring shaped support surface of the cover (14) is positioned between one end of the main spring (18) and the spring seat (S1). The cover (14) functions to enclose and protect the piston (16), the bump rubber (16BR) and other enclosed sub-components from foreign elements such as dust, stones and mud/water. The outer tube (20) is fixed on the open cylindrical portion of the bracket (41).

[0022] The guiding and sealing assembly (20GSA) has, a lower guide (G1) which rests on a circlip (CP) given on inner curved surface of the outer tube (20), an upper guide (G2) having sealing lips that is positioned above the lower guide (G1) so as to rest on upper surface of the lower guide (G1) and a top cap (20TC) located above the upper guide (G2) and fixed to the open end of the outer tube (20). The guiding sealing assembly (20GSA) has a central opening to allow the piston rod (16) to reciprocate. The damping pin (11) is located inside the hollow cylindrical portion of the piston rod (16) above the intermediate hollow cylindrical part (17), the screw (12S) is located above the damping pin (11) and within a hollow space within the bracket (12). The bump rubber (16BR) is located on the piston rod (16) between the top cap (20TC) and a flat fixing nut (12FN) given below the spring seat (S1) on the piston rod (16).

[0023] Referring to Figs. 8 to 10, in the third embodiment of the invention, the details pertaining to inter relation/association/connections between the preload adjustment assembly (50), the ECU (52), the battery (52B), the switch (52S), the sensor (42), the actuation mechanism (10), the communication medium (44) and suspension unit (60) remain the same as that shown in Fig. 1a and as detailed for the first embodiment. The suspension unit (60) of the third embodiment specifically comprises of brackets (12 & 41), main spring (18), an outer tube (20), spring seats (S1 and S3), a base valve assembly (20BVA), a rebound spring (25), a piston rod (16), a guiding and sealing assembly (20GSA), a bump rubber (16BR).

[0024] The piston rod (16) has a hollow cylindrical shape with its one end fitted within the mounting bracket (12). An intermediate hollow cylindrical part (17) is fitted and partially located within the other end of the piston rod (16). The intermediate hollow cylindrical part (17) has a lower cylindrical portion for locating and fixing the piston (19) and the piston (19) is positioned within the outer tube (20). A nut (17S) holds the piston (19) in its position on a lower cylindrical portion of the intermediate hollow cylindrical part (17). The orifice(s) (22) provided on the curved cylindrical surface of the piston rod (16) and the hollow central portion of the piston rod (16) together form a continuous passage for damping fluid with the central opening of the intermediate hollow cylindrical part (17). A set of ribs (16R) and O-rings (16O) are provided on the damping pin (11) above the location of the orifice(s) (22) to prevent any flow of damping fluid above their postion within the suspension unit (60). The rebound spring (25) is located between an annular rib given on the intermediate hollow cylindrical part (17) and the lower surface of the lower guide (G1).

[0025] The main spring (18) is located between the spring seat (S1) given on the bracket (12) and the spring seat (S3) given on the outer tube (20), the spring seat (S3) is itself positioned on the upper surface of the spring preload adjustment ring (30) of the bracket (41). The outer tube (20) is fixed within the open cylindrical portion of the bracket (41), the inner tube (21) is fixed concentrically with the outer tube (20) within the open cylindrical portion of the bracket (41). The base valve assembly (20BVA) is mounted at the base of the open cylindrical portion of the bracket (41) and located within the inner tube (21), a passage given in the bracket (41) below the base valve assembly (20BVA) connects the space given below the base valve assembly (20BVA) and the space between the inner tube (21) and the outer tube (20).

[0026] The guiding and sealing assembly (20GSA) has, a lower guide (G1) having surfaces resting on both the upper surface of inner tube (21) and inner curved surface of the outer tube (20), an upper guide (G2) having sealing lips that is located resting above the lower guide (G1) and has a curved surfaces resting on inner curved surface of the outer tube (20), and a top cap (20TC) located above the upper guide (G2) and fixed to the open end of the outer tube (20). The guiding sealing assembly (20GSA) has a central opening to allow the piston rod (16) to reciprocate. The damping pin (11) is located inside the hollow cylindrical portion of the piston rod (16) above the intermediate hollow cylindrical part (17), the screw (12S) is located above the damping pin (11) and within a hollow space within the bracket (12). The bump rubber (16BR) is located on the piston rod (16) between the top cap (20TC) and a flat fixing nut (12FN) given below the spring seat (S1) on the piston rod (16).

[0027] Referring to Figs. 11 to 14, in the fourth embodiment of the invention, the details pertaining to inter relation/association/connections between the preload adjustment assembly (50), the ECU (52), the battery (52B), the switch (52S), the sensor (42), the actuation mechanism (10), the communication medium (44) and suspension unit (60) remain the same as that shown in Fig. 1a and as detailed for the first embodiment. The suspension unit (60) of the fourth embodiment specifically comprises of brackets (12 & 41), main spring (18 & 24), an outer tube (20), spring seats (S1 and S2), a canister (41GC), a base valve assembly (20BVA), a rebound spring (25), a piston rod (16), a guiding and sealing assembly (20GSA) and a bump rubber (16BR).

[0028] The piston rod (16) has a hollow cylindrical shape with its one end fitted within the mounting bracket (12). An intermediate hollow cylindrical part (17) is fitted and partially located within the other end of the piston rod (16). The intermediate hollow cylindrical part (17) has a lower cylindrical portion for locating and fixing the piston (19) and the piston (19) is positioned within the outer tube (20). A nut (17S) holds the piston (19) in its position on a lower cylindrical portion of the intermediate hollow cylindrical part (17). The orifice(s) (22) provided on the curved cylindrical surface of the piston rod (16) and the hollow central portion of the piston rod (16) together form a continuous passage for damping fluid with the central opening of the intermediate hollow cylindrical part (17). A set of ribs (16R) and O-rings (16O) are provided on the damping pin (11) above the location of the orifice(s) (22) to prevent any flow of damping fluid above their postion within the suspension unit (60). The rebound spring (25) is located between an annular rib given on the intermediate hollow cylindrical part (17) and the lower surface of the lower guide (G1). The main spring (18) is located between the spring seat (S1) given on the bracket (12) and the spring seat (S2) given on the outer tube (20). The main spring (24) is located between lower end of the spring seat (S2) given on the outer tube (20) and a washer (26) located on the upper surface of the spring preload adjustment ring (30) of the bracket (41).

[0029] The outer tube (20) is fixed within the open cylindrical portion of the bracket (41). The inner tube (21) is fixed concentrically with the outer tube (20) within the open cylindrical portion of the bracket (41). The canister (41GC) is fitted on lower end of the bracket (41) and is connected by a passage (41PA) to lower end of the open cylindrical portion of the bracket (41). The base valve assembly (20BVA) is mounted at the base of the open cylindrical portion of the bracket (41) and located within the inner tube (21), a passage given in the bracket (41) below the base valve assembly (20BVA) connects the space given below the base valve assembly (20BVA) and the space between the inner tube (21) and the outer tube (20).

[0030] The guiding and sealing assembly (20GSA) has a lower guide (G1) having surfaces resting on both the upper surface of inner tube (21) and inner curved surface of the outer tube (20), an upper guide (G2) having sealing lips that is located resting above the lower guide (G1) and has a curved surfaces resting on inner curved surface of the outer tube (20), and a top cap (20TC) located above the upper guide (G2) and fixed to the open end of the outer tube (20). The guiding sealing assembly (20GSA) has a central opening to allow the piston rod (16) to reciprocate. The damping pin (11) is located inside the hollow cylindrical portion of the piston rod (16) above the intermediate hollow cylindrical part (17), the screw (12S) is located above the damping pin (11) and within a hollow space within the bracket (12). The bump rubber (16BR) is located on the piston rod (16) between the top cap (20TC) and a flat fixing nut (12FN) given below the spring seat (S1) on the piston rod (16).

[0031] When the motor vehicle user rotates the spring preload adjustment ring (30), the profiled end/threads of the cylindrical piece (32) climbs/descends onto a new position on the projection (41P1)/the threads given on curved surface of the outer tube (20). This compresses/expands the main spring(s) (18 and 24 for first and fourth embodiment, just 18 for the second and third embodiment) which are located between the spring seats (S1, S2 and S3 for the first embodiment, S1 and S3 for the second embodiment and third embodiment, and S1 and the hollow cylindrical cap (34) for the fourth embodiment). The hollow cylindrical cap (34) which is integrated with the cylindrical piece (32) also moves upwards/descends with reference to the magnet (36) when user rotates the spring preload adjustment ring (30). The movement of the hollow cylindrical cap (34) causes change /disruption in the magnetic flux of the magnet (36). This change/disruption in magnetic flux is registered by the sensor (42). The sensor (42) sends a signal to the ECU (52) which indicates the occurrence of a change in sensed postion of the spring preload adjusting ring (30). The ECU (52) depending upon the user selected position of the switch (52S), sends a control signal to the actuation mechanism (10). As such, user can select different switches as per the perceived requirement to cause ECU (52) to load a different reference/look up table for causing damping setting adjustment. This control signal causes the shaft of the actuation mechanism (10) to start moving. This movement is registered by an encoder linked to the actuation mechanism (10) which then communicates it back to the ECU (52). When the shaft of the actuation mechanism (10) reach a specific postion, the ECU (52) causes the actuation mechanism (10) to stop moving by sending another control signal.

[0032] The movement of the shaft of the actuation mechanism (10) causes the screw (12S) to rotate as well. The damping pin (11) which is in firm sliding contact with the screw (12S) moves up/down in response to the movement of the screw (12S) thereby opening/obstructing the orifice of the intermediate hollow cylindrical part (17). This opening/obstructing action changes the flow rate of damping fluid through the central hole of the intermediate hollow cylindrical part (17), hence altering the damping force obtained therefrom. The damping fluid entering central hole of the intermediate hollow cylindrical part (17) exits from orifices (22) on the piston rod (16) that essentially lie above the piston (19). This state of damping fluid flow persists when the suspension unit (60) and hence its main spring(s) is still undergoing compression and therefore in that given moment is only partial compressed. When the suspension unit (60) begins re-expanding under the influence of the energy being released by the main spring(s), the damping fluid flow is reversed. The damping fluid now flows back through the orifice given on the piston rod (16) and out of the central hole given on the intermediate hollow cylindrical part (17). Hence, at any given position of the switch (52S) and the hollow cylindrical cap (34), the magnitude of compression and rebound damping force achieved are different. The number of selectable combinations available are also numerous. The user/rider can hence alter the damping performance to achieve a safe and comfortable range of damping force values for any given road condition and main spring preload/pre-compression setting.

[0033] The piston (19) and the base valve assembly (20BVA) (which is provided only in case of the first, third and fourth embodiment of the invention) also continue to function in accordance with their factory settings regardless of the postion of the damping pin (11). When the suspension unit (60) and hence the main spring(s) is getting compressed, the damping fluid flows from the chamber formed by the inner tube (21), into the chamber formed between the inner tube and the outer tube (20) via the base valve assembly (20BVA). This flow reverses when the suspension unit (60) starts re-expanding under the influence of energy released by the main spring(s). The damping fluid then flows from the chamber formed between the inner tube (21) and the outer tube (20) to the chamber formed by the inner tube (21) alone via the base valve assembly (20BVA).

[0034] The piston (19) that is linked to the piston rod (16) is provided with multiple orifices which are at least two different levels which are covered with their own different set of thin flat flexible metallic rings. The compression of suspension unit (60) causes the piston rod (16) and hence the piston (19) to move into the inner/outer tube. Therefore, during compression, damping fluid to exert a force and bend one set of metallic rings thereby allowing it to flow past it via one set of orifices given on the piston (19). During compression, the other set orifices of the piston (19) remain closed under the other set of metallic rings. The expansion of suspension unit (60) causes damping fluid to exert a force in opposite direction and bend another set of metallic rings thereby allowing the damping fluid flow back past the piston (19) via another set of orifices given on the piston (19). During this time the first set orifices, which were open during compression, remain closed by the first set of metallic rings. This construction allows a bare minimum amount of damping fluid to flow through the piston (19) and the base valve assembly (20BVA) (as provided in the first and fourth embodiments). This thereby allows the piston (19) and the base valve assembly (20BVA) (as provided in the first and fourth embodiments) to provide a baseline damping force during compression and expansion of the suspension unit (60).

[0035] Specifically in case of the first and fourth embodiments, a passage connects the base of the bracket (41) inside the outer tube (20) with the gas canister (41GC). The gas canister (41GC) so connected with the bracket (41), performs the function of keeping the damping fluid under sufficient pressure at all times thereby avoiding foaming of damping fluid/cavitation in the suspension unit during operation of said suspension unit (60). The gas canister (41GC) contains means for maintaining pressure over the damping fluid which can be either a pressurized gas filled bladder or a floating piston supported by a gas, metallic or non-metallic spring. Providing the gas canister (41GC) helps in maintaining consistent damping performance during long periods of rapid compression and expansion of the suspension unit (60).

[0036] The brackets (12 and 41) of the suspension unit (60) are connected to the mounting point on the motor vehicle and the wheel axle respectively. Therefore, the suspension unit (60) is capable of absorbing, releasing and dissipating the energy absorbed when the motor vehicle travels over a road surface irregularity. This thereby aids in providing a smooth motor vehicle riding experience. The damping force characteristics achieved due to the piston (19) and the base valve assembly (20BVA) (as additionally provided in the first and fourth embodiments) become fixed at the end of designing stage of the suspension unit. Whereas, the damping force characteristics achieved due to the positioning of the damping pin (11) above the central hole of the intermediate hollow cylindrical part (17) can be changed by the damping control system (100). The damping control system (100) therefore allows a unique resultant damping force characteristic to be achieved at different settings of the switch (52S). The damping force characteristics achieved due to a given position of the damping pin (11) above the central hole of the intermediate hollow cylindrical part (17), are considered along with the values achievable due to the orifice(s) (22) given on the piston rod (16).

[0037] Thus, the novel architecture of the damping control system (100) in suspension of a motor vehicle as disclosed above provides following technical advantages contributing to technical advancement of technology domain of damping control systems.
- The system is simple and compact in construction and hence is easy to manufacture and install motor vehicles, particularly in two wheeled vehicles.
- The system requires a sensor to be mounted on only one suspension unit to reliably sense the change in position of the spring preload adjuster.
- The system automatically adjust and balance the damping force against any adjustment made to the spring preload based upon sensed change in postion of the preload adjuster.
- The system is configured to accept user input to modulate the damping adjustment that is given to the suspension unit.
- It enhances rider comfort and safety in a motor vehicle, particularly two wheeled vehicles, in wide variety of operating conditions.
- The system provides consistent performance in a variety of operating conditions.

[0038] A person skilled in the art can arrive at different profiles for the sub-components of the preload adjustment assembly (50). Such different profiles must not be perceived to be placing the variants of the damping control system, arising of such alteration/change, outside the scope of this invention as long as the inter-relation/association/connection between said sub-components and other components of the suspension unit remains the same. More specifically, the profile of the bracket (40), the construction of the piston (19) and the base valve assembly (20BVA) can be altered or changed by person skilled in the art. Again, as long as the inter-relation/association/connection between said sub-components and other components of the suspension unit remains the same, the variant so achieved lies within the scope of this invention.

[0039] It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein. ,CLAIMS:We Claim

1. A damping control system (100) in suspension of a motor vehicle comprising of at least a preload adjustment assembly (50), an Electronic Control Unit (52), sensor (42), actuation mechanism (10), a communication module (44) and a suspension unit (60); wherein
- the preload adjustment assembly (50) comprising of a spring preload adjustment ring (30), a cylindrical piece (32), a hollow cylindrical cap (34), a magnet (36), a bracket (40, 40U) and a sensor (42) is mounted below the spring(s) provided on the suspension unit (60) and is in communication with the ECU (52) through the communication module (44);
- the actuation mechanism (10) is mounted on a bracket (12) of the suspension unit (60) and is in continuous communication with the ECU (52), through the communication module (44); and
- said ECU (52) is mounted inside the vehicle in close proximity of the sensor (42) and is configured to control the damping characteristics through the actuating mechanism (10) in response to the change in preload of main spring(s) (18, 24).

2. The damping control system (100) as claimed in claim 1, wherein
- the cylindrical piece (32), forming a single integral structure with the spring preload adjustment ring (30) given at its upper end and the hollow cylindrical cap (34) at its lower end, is rotatably mounted below the main spring(s) (18, 24) in such way that it is concentric with the outer tube (20); the profiled lower surface of the cylindrical piece (32) is located on the projection (41P1) given on the outer curved surface of a bracket (41) of the outer tube (20);
- the magnet (36) is mounted on the flat surface of a projection (41P1) given on the bracket (41) of outer tube (20) in such way that the hollow cylindrical cap (34) cuts the communication (magnetic flux) between the magnet (working as transmitter) (36) and the sensor (receiver) (42); and
- the sensor (42) is mounted on an inner surface of a profiled bracket (40).

3. The damping control system (100) in suspension of a motor vehicle as claimed in claim 1, wherein
- the cylindrical piece (32) forms a single integral structure with the hollow cylindrical cap (34) located concentrically with it, the spring preload adjustment ring (30) is located at a levelled horizontal plane of the hollow cylindrical cap (34) and forms a single integral structure with the hollow cylindrical cap (34);
- the adjustment ring (30), the cylindrical piece (32) and the hollow cylindrical cap (34) are rotatably mounted below the main springs (18, 24) so as to be concentric with the outer tube (20), a washer (26) and/or spring seat (S3) is(are) located between the main spring (24) and the hollow cylindrical cap (34);
- the cylindrical piece (32) is configured so as to interact with the outer curved surface of the outer tube (20) and the lower surface of said cylindrical piece (32) is located above the projection (41P1); and
- the magnet (36) is mounted on inside flat surface of one leg of the bracket (40U) and the sensor (42) is mounted on inside flat surface of the other leg of the bracket (40U) in such way that the hollow cylindrical cap (34) cuts communication (magnetic flux) between the magnet (36) (working as transmitter) and the sensor (42) (receiver).

4. The damping control system (100) as claimed in any of the claims 2 and 3, wherein
- the sensor (42) is in communication with to the ECU (52) by the communication module (44);
- the actuation mechanism (10) is fitted on the bracket (12) of the suspension unit (60) and is in continuous communication with the ECU (52) through communication module (44); and
- said ECU (52) is mounted inside the vehicle in close proximity of the sensor (42) and is configured to control the damping characteristics automatically through the actuation mechanism (10) in response to the change in preload of the main spring(s) (18, 24) sensed by the sensor (42).

5. The damping control system (100) as claimed in claim 4, wherein
- the actuation mechanism (10) is selected from a motor, mechanical actuation, hydraulic actuation, pneumatic actuation and electro-magnetic mechanism; and
- in case of the motor as the actuation mechanism (10), the shaft of said motor is rigidly fixed to a screw (12S) inside the bracket (12) of the suspension unit (60) in such way that it makes positive and continuous communication with the said screw (12S).

6. The damping control system (100) as claimed in claim 5, wherein
- said system (100) is provided with a switch (52S) and a battery (52B) and said switch (52S) and said battery (52B) are in communication with the controller (52) through the communication module (44);
- the communication module (44) is selected from a group of wired communication (wiring harness), wireless communication and combination of thereof; and
- the sensor (42) is preferably selected from a Hall Effect sensor.
7. The damping control system (100) as claimed in claim 6, wherein
the suspension unit (60) comprises of brackets (12 & 41), main spring (18 & 24), an outer tube (20), spring seats (S1, S2 and S3), a canister (41GC), a base valve assembly (20BVA), a rebound spring (25), a piston rod (16), a guiding and sealing assembly (20GSA) and a bump rubber (16BR); wherein
- the piston rod (16) has a hollow cylindrical shape with its one end fitted within the mounting bracket (12), an intermediate hollow cylindrical part (17) is fitted and partially located within the other end of the piston rod (16), the intermediate hollow cylindrical part (17) has a lower cylindrical portion for locating and fixing the piston (19) and the piston (19) is positioned within the outer tube (20), orifice(s) (22) provided on the curved cylindrical surface of the piston rod (16) and the hollow central portion of the piston rod (16) together form a continuous passage with the central opening of the intermediate hollow cylindrical part (17), a set of ribs (16R) and O-rings (16O) are provided on the damping pin (11) above the location of the orifice(s) (22) to prevent any flow of damping fluid above their position; and
- the rebound spring (25) is located between an annular rib given on the intermediate hollow cylindrical part (17) and the lower surface of the lower guide (G1).

8. The damping control system (100) as claimed in claim 7, wherein
- the main spring (18) is located between the spring seat (S1) given on the bracket (12) and the spring seat (S2) given on the outer tube (20), the main spring (24) is located between lower end of the spring seat (S2) given on the outer tube (20) and a washer (26) located on the spring seat (S3) which itself is positioned on the upper surface of the spring preload adjustment ring (30) of the bracket (41);
- the outer tube (20) is fixed within the open cylindrical portion of the bracket (41), the inner tube (21) is fixed concentrically with the outer tube (20) within the open cylindrical portion of the bracket (41), the canister (41GC) is fitted on lower end of the bracket (41) and is connected by a passage (41PA) to lower end of the open cylindrical portion of the bracket (41);
- the base valve assembly (20BVA) is mounted at the base of the open cylindrical portion of the bracket (41) and located within the inner tube (21), a passage given in the bracket (41) below the base valve assembly (20BVA) connects the space given below the base valve assembly (20BVA) and the space between the inner tube (21) and the outer tube (20);
- the guiding and sealing assembly (20GSA) has a lower guide (G1) having surfaces resting on both the upper surface of inner tube (21) and inner curved surface of the outer tube (20), an upper guide (G2) having sealing lips that is located resting above the lower guide (G1) and has a curved surfaces resting on inner curved surface of the outer tube (20), a top cap (20TC) located above the upper guide (G2) and fixed to the open end of the outer tube (20), the guiding sealing assembly (20GSA) has a central opening to allow the piston rod (16) to reciprocate;
- the damping pin (11) is located inside the hollow cylindrical portion of the piston rod (16) above the intermediate hollow cylindrical part (17), the screw (12S) is located above the damping pin (11) and within a hollow space within the bracket (12); and
- the bump rubber (16BR) is located on the piston rod (16) between the top cap (20TC) and a flat fixing nut (12FN) given below the spring seat (S1) on the piston rod (16).

9. The damping control system (100) as claimed in claim 6, wherein
the suspension unit (60) comprises of brackets (12 & 41), main spring (18), an outer tube (20), spring seats (S1 and S3), a piston rod (16), a guiding and sealing assembly (20GSA) and a bump rubber (16BR); wherein
- the piston rod (16) has a hollow cylindrical shape with its one end fitted within the mounting bracket (12), an intermediate hollow cylindrical part (17) is fitted and partially located within the other end of the piston rod (16), the intermediate hollow cylindrical part (17) has a lower cylindrical portion for locating and fixing the piston (19), and the piston (19) is positioned concentrically and movably within the outer tube (20), orifice(s) (22) provided on the curved cylindrical surface of the piston rod (16) and the hollow central portion of the piston rod (16) together form a continuous passage with the central opening of the intermediate hollow cylindrical part (17), a set of ribs (16R) and O-rings (16O) are provided on the damping pin (11) above the location of the orifice(s) (22) to prevent any flow of damping fluid above their postion; and
- the intermediate hollow cylindrical part (17) is provided with an annular rib and said annular rib rests on the lower surface of the lower guide (G1).

10. The damping control system (100) as claimed in claim 9, wherein
- the main spring (18) is located between the spring seat (S1) given on the bracket (12) and the spring seat (S3) given on the outer tube (20), the spring seat (S3) itself is positioned on the upper surface of the spring preload adjustment ring (30) of the bracket (41);
- the outer tube (20) is fixed on the open cylindrical portion of the bracket (41);
- the guiding and sealing assembly (20GSA) has a lower guide (G1) which rests on a circlip (CP) given on inner curved surface of the outer tube (20), an upper guide (G2) having sealing lips that is positioned above the lower guide (G1) so as to rest on upper surface of the lower guide (G1) and a top cap (20TC) located above the upper guide (G2) and fixed to the open end of the outer tube (20), the guiding sealing assembly (20GSA) has a central opening to allow the piston rod (16) to reciprocate;
- the damping pin (11) is located inside the hollow cylindrical portion of the piston rod (16) above the intermediate hollow cylindrical part (17), the screw (12S) is located above the damping pin (11) and within a hollow space within the bracket (12); and
- the bump rubber (16BR) is located on the piston rod (16) between the top cap (20TC) and a flat fixing nut (12FN) given below the spring seat (S1) on the piston rod (16).

11. The damping control system (100) as claimed in claim 6, wherein
the suspension unit (60) comprises of brackets (12 & 41), main spring (18), an outer tube (20), spring seats (S1 and S3), a base valve assembly (20BVA), a rebound spring (25), a piston rod (16), a guiding and sealing assembly (20GSA) and a bump rubber (16BR); wherein
- the piston rod (16) has a hollow cylindrical shape with its one end fitted within the mounting bracket (12), an intermediate hollow cylindrical part (17) is fitted and partially located within the other end of the piston rod (16), the intermediate hollow cylindrical part (17) has a lower cylindrical portion for locating and fixing the piston (19) and the piston (19) is positioned within the outer tube (20), orifice(s) (22) provided on the curved cylindrical surface of the piston rod (16) and the hollow central portion of the piston rod (16) together form a continuous passage with the central opening of the intermediate hollow cylindrical part (17), a set of ribs (16R) and O-rings (16O) are provided on the damping pin (11) above the location of the orifice(s) (22) to prevent any flow of damping fluid above their postion; and
- the rebound spring (25) is located between an annular rib given on the intermediate hollow cylindrical part (17) and the lower surface of the lower guide (G1).

12. The damping control system (100) as claimed in claim 11, wherein
- the main spring (18) is located between the spring seat (S1) given on the bracket (12) and the spring seat (S3) given on the outer tube (20), the spring seat (S3) is itself positioned on the upper surface of the spring preload adjustment ring (30) of the bracket (41);
- the outer tube (20) is fixed within the open cylindrical portion of the bracket (41), the inner tube (21) is fixed concentrically with the outer tube (20) within the open cylindrical portion of the bracket (41);
- the base valve assembly (20BVA) is mounted at the base of the open cylindrical portion of the bracket (41) and located within the inner tube (21), a passage given in the bracket (41) below the base valve assembly (20BVA) connects the space given below the base valve assembly (20BVA) and the space between the inner tube (21) and the outer tube (20);
- the guiding and sealing assembly (20GSA) has a lower guide (G1) having surfaces resting on both the upper surface of inner tube (21) and inner curved surface of the outer tube (20), an upper guide (G2) having sealing lips that is located resting above the lower guide (G1) and has a curved surfaces resting on inner curved surface of the outer tube (20), a top cap (20TC) located above the upper guide (G2) and fixed to the open end of the outer tube (20), the guiding sealing assembly (20GSA) has a central opening to allow the piston rod (16) to reciprocate;
- the damping pin (11) is located inside the hollow cylindrical portion of the piston rod (16) above the intermediate hollow cylindrical part (17), the screw (12S) is located above the damping pin (11) and within a hollow space within the bracket (12); and
- the bump rubber (16BR) is located on the piston rod (16) between the top cap (20TC) and a flat fixing nut (12FN) given below the spring seat (S1) on the piston rod (16).

13. The damping control system (100) in suspension of a motor vehicle as claimed in claim 6, wherein
the suspension unit (60) comprises of brackets (12 & 41), main spring (18 & 24), an outer tube (20), spring seats (S1 and S2), a canister (41GC), a base valve assembly (20BVA), a rebound spring (25), a piston rod (16), a guiding and sealing assembly (20GSA) and a bump rubber (16BR); wherein
- the piston rod (16) has a hollow cylindrical shape with its one end fitted within the mounting bracket (12), an intermediate hollow cylindrical part (17) is fitted and partially located within the other end of the piston rod (16), the intermediate hollow cylindrical part (17) has a lower cylindrical portion for locating and fixing the piston (19) and the piston (19) is positioned within the outer tube (20), orifice(s) (22) provided on the curved cylindrical surface of the piston rod (16) and the hollow central portion of the piston rod (16) together form a continuous passage with the central opening of the intermediate hollow cylindrical part (17), a set of ribs (16R) and O-rings (16O) are provided on the damping pin (11) above the location of the orifice(s) (22) to prevent any flow of damping fluid above their postion; and
- the rebound spring (25) is located between an annular rib given on the intermediate hollow cylindrical part (17) and the lower surface of the lower guide (G1).

14. The damping control system (100) as claimed in claim 13, wherein
- The main spring (18) is located between the spring seat (S1) given on the bracket (12) and the spring seat (S2) given on the outer tube (20), the main spring (24) is located between lower end of the spring seat (S2) given on the outer tube (20) and a washer (26) located on the upper surface of the spring preload adjustment ring (30) of the bracket (41);
- the outer tube (20) is fixed within the open cylindrical portion of the bracket (41), the inner tube (21) is fixed concentrically with the outer tube (20) within the open cylindrical portion of the bracket (41), the canister (41GC) is fitted on lower end of the bracket (41) and is connected by a passage (41PA) to lower end of the open cylindrical portion of the bracket (41);
- the base valve assembly (20BVA) is mounted at the base of the open cylindrical portion of the bracket (41) and located within the inner tube (21), a passage given in the bracket (41) below the base valve assembly (20BVA) connects the space given below the base valve assembly (20BVA) and the space between the inner tube (21) and the outer tube (20);
- the guiding and sealing assembly (20GSA) has a lower guide (G1) having surfaces resting on both the upper surface of inner tube (21) and inner curved surface of the outer tube (20), an upper guide (G2) having sealing lips that is located resting above the lower guide (G1) and has a curved surfaces resting on inner curved surface of the outer tube (20), a top cap (20TC) located above the upper guide (G2) and fixed to the open end of the outer tube (20), the guiding sealing assembly (20GSA) has a central opening to allow the piston rod (16) to reciprocate;
- the damping pin (11) is located inside the hollow cylindrical portion of the piston rod (16) above the intermediate hollow cylindrical part (17), the screw (12S) is located above the damping pin (11) and within a hollow space within the bracket (12); and
- the bump rubber (16BR) is located on the piston rod (16) between the top cap (20TC) and a flat fixing nut (12FN) given below the spring seat (S1) on the piston rod (16).

15. The damping control system (100) as claimed in any of the claims 8, 10, 12 and 14; wherein the suspension unit (60) has a damping unit and said damping unit is selected from a hydraulic damper, emulsion damper, and gas filled damper.

Dated 23rd day of May 2022

Sahastrarashmi Pund
Head – IPR
Endurance Technologies Ltd.

To,
The Controller of Patents,
The Patent Office, at Mumbai