DESC:FIELD OF THE INVENTION
[0001] The present disclosure is generally related to a shock absorber and more particularly, the present disclosure is related to a rebound stop arrangement provided within the shock absorber for the expansion stroke of the shock absorber.

BACKGROUND OF THE INVENTION
[0002] Shock absorbers are utilized by almost every type of vehicle. Shock absorber helps the vehicle absorb shock impacts like a pothole, irregular terrain and hence absorb the effects that may provide discomfort to a user when operating the vehicle.
[0003] Current shock absorbers use a plastic rebound stopper to absorb the expansion stroke end hits. During expansion stroke of the shock absorber, the piston of the shock absorber expands internally and may hit at the shock absorber body at a fully extended position. Rebound stoppers help in damping such impacts during the expansion stroke and improve the ride quality. Since the conventional plastic rebound stopper is a rigid member with very less cushioning effects, it still transmits a sudden hit or jerk with noise to the rider, which is a discomfort to the rider.
[0004] A solution adopted by the industry to solve this problem is to use rebound stoppers made up of more flexible materials as compared to a plastic one.
[0005] Another solution used is to provide a helical bound spring in order to provide end cushioning.
[0006] However, for both the above solutions, current packaging space for this specific application is a constraint and also, the stiffness and durability requirements are not met through these current approaches.
[0007] Therefore, there is a need of a more efficient shock absorber in order to solve discomfort problems to the operating user.

BRIEF SUMMARY
[0008] It will be understood that this disclosure is not limited to the particular systems, and methodologies described, as there can be multiple possible embodiments of the present disclosure which are not expressly illustrated in the present disclosure. It is also to be understood that the terminology used in the description is to describe the particular versions or embodiments only, and is not intended to limit the scope of the present disclosure.
[0009] In an example embodiment, a rebound stop arrangement is provided within the shock absorber. This arrangement is provided for the expansion stroke of the shock absorber. The shock absorber includes an outer casing tube disposed in a vertically extended direction, wherein said outer casing tube includes an upward portion and a lower portion, a rod guide disposed coaxially within the outer casing, a piston placed inside the outer casing tube configured to move up or down; and a piston rod having an upper and a lower portion, operably connected to a vehicle portion through its upper portion and the piston through its lower portion, ingressing the outer casing tube through the rod guide wherein the piston rod comprises, at its lower portion, at least one coned disc.

BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying drawings illustrate various embodiments of systems, methods, and embodiments of various other aspects of the disclosure. Any person with ordinary skills in the art will appreciate that the illustrated element boundaries (e.g. boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. It may be that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of one element may be implemented as an external component in another, and vice versa. Furthermore, elements may not be drawn to scale. Non-limiting and non-exhaustive descriptions are described with reference to the following drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating principles.
[0011] Fig. 1 illustrates a diagram of a conventional shock absorber;
[0012] Fig. 2 illustrates a shock absorber, in accordance with an embodiment of the invention.
[0013] Fig. 3A-3B illustrates advantages of using coned disc, in accordance with an embodiment of the invention.
[0014] Fig. 4 illustrates specific shape and structure with various dimension of at least one coned disc in accordance with an embodiment of the invention.

DETAILED DESCRIPTION
[0015] Embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings in which like numerals represent like elements throughout the several figures, and in which example embodiments are shown. Embodiments of the claims may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The examples set forth herein are non-limiting examples and are merely examples among other possible examples.
[0016] Some embodiments of this invention, illustrating all its features, will now be discussed in detail. The words “comprising,” “having,” “containing,” and “including,” and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.
[0017] It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, the preferred, systems and methods are now described.
[0018] Further, it must also be noted that the invention has been explained in terms of a dual tubeshock absorber however, the invention may be adapted to a monotube type shock absorber as well. It is also to be noted that there may be a dust cover 100A present within assembly of the shock absorber described. Furthermore, an external coil spring may also be present which has been eliminated from the description for ease of understanding. It is to be understood that the described shock absorber generally has a coil spring surrounding it.
[0019] FIG. 1 illustrates a shock absorber 100 according to prior art. The shock absorber may include an outer casing 101 disposed in a vertically extended direction, that includes an upward portion 101A and a lower portion 101B. Essentially, the shock absorber 100 may further include a rod guide 104 that may be disposed coaxially within the outer casing tube 101. The rod guide 104 is placed within the outer casing tube 101. The shock absorber 100 further includes a piston 116 that may be configured to move up and down during expansion and compression stroke of the shock absorber 100.
[0020] The shock absorber 100 further includes a piston rod 108 inside the outer casing tube 101 wherein, the piston rod 108 is connected to vehicle through its upper portion and to the piston 116 through its lower portion. The piston rod 108 is kept at its place by the rod guide 104 within the outer casing 101. The piston rod 108, further includes a rebound stop 114 that may be made up of rubber, or plastic in order to absorb any impact that is caused during expansion stroke of the shock absorber 100 wherein the rebound stopper 114 meets the rod guide during expansion stroke more specifically at end of the expansion stroke.
[0021] In the present inventions as depicted by Fig. 2, the rebound stopper114 in fig 1 is replaced by a single or a stack of coned discs 202 Fig 2. This arrangement acts as a gradual force absorbing member in place of sudden jerk imposed by expansion stroke at end. It also, eliminates noise caused by a sudden hit. To provide placement of such a stack of coned discs 202, a two stepped machined surface is provided on the piston rod 108 that helps to positively lock the at least one coned disc 202. It is to be appreciated that there may be a single coned disc or multiple stacked coned discs stacked together to produce the cushioning effect.
[0022] It is also to be noted that the piston rod 108 is in the form of a two stepped cylindrical piston rod which includes a first step 108A and a second step 108B. The stack of coned discs 202 abut against the first step 108A. The part of the piston rod 108 between the first step 108A and the second step 108B has a lesser cross-sectional diameter than the one post the second step 108B.
[0023] Also, the piston rod 108 includes a machined step in order to accommodate the stack of coned discs 202. This machining out of the piston rod 108, reduces the weight of the overall shock absorber 200 and makes it light weight to be used in vehicles. According to an embodiment of the invention, the machined step may be a circular machined step. It is to be appreciated the machined step is of a lesser measurement than the full cross section of the piston rod 108.
[0024] The various dimensions of the shock absorber 101 and the coned spring arrangement 202 are as follows:
The stack of coned discs has an internal disc diameter is of 11.2mm.
The stack of coned discs has an internal disc diameter within a range of 5~15mm.
The stack of coned discs has an external disc diameter of 22.5 mm.
The stack of coned discs has an external disc diameter within a range of 8-46mm.
The single coned disc has a free height of 1.75 mm.
The stack of coned discs has a free height within a range of 0.50-20mm.
The single coned discs has a free cone height of 0.50mm.
The stack of coned discs has a free cone height within a range of 0.2 ~7 mm.
The stack of coned discs are placed in a stack/ Single piece.
The free height of the stack is of 11.1mm. The free height of the stack/single piece is within a range of 0.45~40.
The compressed height of the stack is of 7.5mm.
The compressed height of the stack/single piece is within a range of 0.2-30mm.
[0025] However, as shown in Fig. 3B, illustrating usage of a two stepped piston rod 108 of the shock absorber 200, for a same downward force of X Nm, the height required is H2 wherein, H1>H2.
[0026] As another example similar to above observation, for a load of 2509 Nm, height required for a same stroke in terms of a helical spring is approximately 32.5 mm free length. However, for a similar 2509 Nm of force, height required of the coned discs 202 to provide same stroke, according to the advantage of invention, is 10.05 mm. Therefore, the height constraints are reduced to upto approx. 1/3rd of the helical spring’s height (reduced packaging space) for a similar load value.
[0027] In other features, the diameter of the coned discs required are also lesser than the helical spring’s diameter.
[0028] Although, it may be argued that placing the stack of coned discs 202 in place of a plastic stopper as in the background art may increase the weight. However, the machined step in which, material from piston rod is removed to accommodate the stack of coned discs 202 reduces the weight and hence, it may be comparable or lesser in weight than the piston with Plastic stopper which is not smooth during expansion strokes.
[0029] Referring now to Fig. 4 that illustrates specific cone shape of coned discs 202, structure and various dimensions in accordance with an embodiment of the invention.
[0030] The coned disc 202 includes a conical structure with a horizontal plate 400A which continues both sides to conical parts 401A and 401B. The length of the horizontal plate i.e. 402 is termed as internal disc diameter. Further, the full length of the coned disc i.e. 408 is termed as external disc diameter. Further, height at which the conical parts 401A and 401B raise the horizontal part is termed as free height 406 of the coned disc 202. Also, height 404 from the base of the horizontal plate 400A till the base of the coned disc 202 as displayed in the figure is termed as free cone height. Further, the thickness of disc i.e. 410 is appropriately displayed within the figure. It is to be appreciated that the free cone height of the disc 410 = free height 406 – thickness of disc 410.
[0031] Moreover, although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

,CLAIMS:We claim,

1. A shock absorber comprising:
an outer casing tube disposed in a vertically extended direction, wherein the outer casing tube includes an upward portion and a lower portion;
a rod guide disposed coaxially within the outer casing;
a piston placed inside the outer casing tube configured to move up or down; and
a piston rod having an upper and a lower portion, operably connected to a vehicle portion through its upper portion and the piston through its lower portion, ingressing the outer casing tube through the rod guide wherein the piston rod comprises, at its lower portion, at least one coned disc.
2. The shock absorber of claim 1, wherein the piston rod includes a machined step.
3. The shock absorber of claim 2, wherein the plurality of coned discs are locked positively in the machined step.
4. The shock absorber of claim 1, wherein the piston rod has a two stepped construction having a first step and a second step.
5. The shock absorber of claim 4, wherein the coned discs abut against the second step.
6. The shock absorber of claim 1, wherein the at least one coned disc has an internal disc diameter within a range of 5~15mm and preferably an internal disc diameter of 11.2mm.
7. The shock absorber of claim 6, wherein the at least one coded disc has an external disc diameter within a range of 8-46mm and preferably an external disc diameter of 22.5mm.
8. The shock absorber of claim 1, wherein the at least one coned discs are placed in a stack/ Single piece.
9. The shock absorber of claim 7, wherein a free height of the stack/single piece is within a range of 0.50~20mm and preferably a free height of 0.50mm.
10. The shock absorber of claim 8, wherein a compressed height of the stack is within a range of 0.20~30mm and preferably a compressed heigh of 7.5mm.