Claims:We Claim:
1. A suspension assembly (135) for a step through type vehicle (100), where said suspension assembly (100) comprising:
An outer tube (301);
An inner tube (302) having two ends where one end is slidably connected to one end of said outer tube (301);and
Said outer tube (301) is divided into two parts, main cylinder body (313) and bottom axle bracket (312), where said bottom axle bracket (312) has a projected portion (401) to engage a piston (303) of said suspension assembly (100).
2. The suspension assembly (135) as claimed in claim 1, wherein said piston (303) includes piston rod (303a) and piston head (303b)
3. The suspension assembly as claimed in claim 1 or claim 2, wherein said projected portion (401) has threaded portion (403) which conforms with the threaded portion (404) of said piston rod (303a).
4. The suspension assembly (135) as claimed in claim 1, wherein said projected portion (401) is fixedly attach to said bottom axle bracket (312).
5. The suspension assembly (135) as claimed in claim 4, wherein said projected portion (401) is disposed orthogonal to upper surface (402) of said bottom axle bracket (312).
6. A suspension assembly (135) for a step through vehicle (100), where said suspension assembly (135) comprising:
An outer tube (301);
An inner tube (302) having two ends where one end is slidably connected to one end of said outer tube (301); and
Said outer tube (301) is divided into two parts, main cylinder body (313) and bottom axle bracket (312), where said bottom axle bracket (312) has a cylindrical threaded opening (507) which attaches a piston (303) of said suspension assembly (135).
7. The suspension assembly (135) as claimed in claim 6, wherein said piston (303) includes piston rod (303a) and piston head (303b).
8. The suspension assembly (135) as claimed in claim 6, wherein said bottom axle bracket has two-part, outer region (508) and inner region (509), where said inner region (509) has a cylindrical threaded opening (507).
9. The suspension assembly (135) as claimed in claim 8, wherein said cylindrical threaded portion (507) has an outer diameter D.
10. The suspension assembly (135) as claimed in claim 8, wherein said outer diameter D is in predetermined range of 5mm to 15mm.
11. The suspension assembly (135) as claimed in claim 7, wherein said piston rod (303a) has a depressed portion (511) having threaded portion (510), where said depressed portion (511) having threaded portion (510) is detachably attached to said cylindrical threaded opening (507) of said inner region (509) of said bottom axle bracket (312).
12. The suspension assembly (135) as claimed in claim 1 or claim 6, wherein said main cylinder body (313) and said bottom axle bracket (312) is detachably attached by press fit and a grub screw (504).
13. The suspension system (135) as claimed in claim 1 or claim 6, wherein said main cylinder body (313) and said bottom axle bracket (312) has a sealing member (503) disposed in between said main cylinder body (313) and bottom axle bracket (312).
14. The suspension system (135) as claimed in claim 1 or claim 6, wherein said bottom axle bracket (312) includes a brake anchor (505), where said brake anchor (505) is an integral part of said bottom axle bracket (312).
15. The suspension system (135) as claimed in claim 1 or claim 6, wherein said bottom axle bracket (312) has an opening (506) to attach a wheel axle from it.
16. The suspension assembly as claimed in claim 1 or claim 6, wherein said main cylinder body (313) includes a fender assembly bracket (501) to attach a fender assembly.
, Description:TECHNICAL FIELD
[0001] The present subject matter relates generally to a saddle type vehicle. More particularly, the present subject matter relates to a front fork assembly for the saddle type vehicles.
BACKGROUND
[0002] Typically, vehicle layout design for a backbone frame type vehicle features a step-through frame and a flat surface called as a floorboard used for disposing legs of a rider when the rider puts his/her feet on the floorboard. Further, the vehicle features bodywork that conceals all or most of the mechanisms. Since, most of the parts in the vehicle are concealed by the body, the body parts are to be designed such that they fit into the body space achieving optimum utilization of space in the vehicle. Traditionally, the small size vehicle wheels are smaller than conventional wheels. The smaller size of the small size vehicle, lower handle bar height in addition to compact packaging of front suspension assembly and smaller wheels requires a suspension assembly of the vehicle to have small suspension assembly. Therefore, taking space constraint and the typical vehicle layout of the small size vehicles into consideration, a suitable small suspension assembly is used in the backbone frame type vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The detailed description is described with reference to a saddle type two wheeled vehicle along with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0004] Fig.1 is a side view of the step through type vehicle.
[0005] Fig. 2 is a perspective view of the backbone frame structure as per one embodiment of the present invention.
[0006] Fig. 3 is a sectional view of the suspension assembly as per one embodiment of the present invention
[0007] Fig. 4 is an exploded view of the outer tube with the bottom axle bracket as per one embodiment of the present invention.
[0008] Fig. 4a is a top view of the bottom axle bracket with projected member as per one embodiment of the present invention.
[0009] Fig. 4b is a side view of the piston rod as per one embodiment of the present invention.
[00010] Fig.5 is an exploded view of suspension assembly with the bottom axle bracket as per another embodiment of the present invention.
[00011] Fig. 5a is a side view of the bottom axle bracket with the brake anchor as per another embodiment of the present invention.
[00012] Fig. 5b is an inclined view of the bottom axle bracket and piston rod as per another embodiment of the present invention.
DETAILED DESCRIPTION
[00013] Generally, several types of vehicles utilize one or more suspension assemblies operably positioned between one or more wheels of the vehicle and the body of the vehicle. The operator control is improved by the suspension assemblies as it absorbs the bumps or any other irregularities, in the surface where the vehicle is moving/traversing. The straddle/ saddle/ step through type vehicles having a single front wheel often use a front suspension assembly to absorbs the bumps encountered by the front wheel. The elastic member and the damping fluid present inside the front suspension assembly govern the performance of the front suspension assembly and also maintain the stability of the vehicle.
[00014] Such suspension assemblies typically include a pair of fork legs arranged on opposing sides of the front wheel. Each fork leg includes an upper fork tube engaged with a lower fork tube. A separately formed bracket member interconnects an upper end of the fork legs and is coupled to a handlebar assembly of the vehicle. The front wheel of the vehicle is usually supported by a lower end of the fork legs. Impact forces are imparted on the front wheel as the vehicle encounters bumps, or other irregularities, of the surface on which it is traversing. These forces are transferred to the junction of the bracket member and the upper fork tubes.
[00015] Further, there are two main types of front fork assembly which are in current use, namely telescopic forks and leading link forks respectively. The telescopic fork comprises of two parallel legs each formed as a pair of co-centric tubular member having resilient suspension means acting between the two, and a wheel spindle is rigidly connected to and extends between the lower end of two legs. Further, typically, the telescopic type of small suspension assembly used in the vehicles operate under two modes, viz., an extension stroke, and a compression stroke. Further, the load carrying capacity of the suspension assembly depends on the elastic member which is typically a compression spring design, space available for the compression spring and the quantity of oil filled inside the suspension assembly.
[00016] In the leading link fork arrangement, a pair of parallel rigids, and usually tubular, legs are provided, and the wheel spindle is connected thereto by a pair of suspension links which are pivotally attached to the lower ends of the legs. Suspension springs are connected at their ends to points part-way along the suspension links and the legs respectively. In this case therefore the only relative movement of parts of the assembly to provide the suspension, is at the pivotal connection of the suspension links and the fork legs.
[00017] Typically, a conventional front suspension assembly comprises an inner tube slidably connected to an outer tube. The inner tube of the front suspension assembly is mounted to the handle bar assembly and the outer tube is mounted to an axle of a front wheel. The main spring assembled inside the fork is engaged to the anchor plate present in the anchor rod assembly which has provisions to which one end of main spring is engaged. Other end of the main spring is also engaged to a top anchor which has anchor plate similar to that provided in anchor rod assembly. The top anchor consists of anchor plate which is welded to a threaded locating member. The top anchor plate with spring engaged to it is held in its position by fastening a nut to a threaded locating member further supported by a bent welded washer in the inner tube. One or more bushes are provided on the outer diameter of spring to avoid spring rubbing with inner tube.
[00018] Suspension assembly is also filled with hydraulic fluid which helps in lubricating various child parts present inside the fork as well as dissipating the heat energy generated as a result of damping of the shock loads & vibrations. A pair of dust seal and oil seal is also provided to avoid entry of foreign particles into the fork assembly and leakage of hydraulic fluid from the fork. In this kind of design, it is the top anchor which is used as a guide to locate suspension assembly onto the upper bracket and the clamping of fork to upper bracket is done by fastening a nut to the threaded portion of the top anchor.
[00019] Further, the performance of suspension assembly to deliver improved riding comfort is achieved by introducing hydraulic damping and air load characteristics. This requires changes in child parts one of which is the addition of top bolt cap member to provide sealing and generate air load. It is in this aspect that a bolt cap member is used to mount the inner tube of the front suspension assembly to the handle bar assembly such that it seals the fork assembly.
[00020] The bolt cap member is connected to the inner tube either through thread engagement or through a snap ring. The bolt cap member supports the main spring of fork assembly. Further, a sealing member is provided on the bolt cap member which prevents leakage of fluid present inside the fork. Spinning is done at one end of the inner tube which provides required seating support to a rebound spring or a rebound rubber. Rebound spring or rubber restricts the rebound stroke of the fork. The separation of inner tube from outer tube is avoided by the piston head, rebound spring/rubber and inner tube interaction which act as a stopper.
[00021] Further, a piston rod is disposed and connected to the outer tube. A portion of the piston rod provides a seating surface to the elastic member. The piston rod consists of one or more holes configured to provide required damping due to the motion of damping fluid inside the front suspension assembly. The elastic member is disposed inside the inner tube. The elastic member receives support from the piston head. The inner tube is prevented from slipping out of the outer tube by assembling with the piston head, a rebound spring, and further interaction with the inner tube. Further, to facilitate proper functioning of the front suspension assembly, a pair of bushes are disposed either on the inner tube or on the outer tube, one mounted on the outer tube and other mounted either on the outer tube or the inner tube, the pair of bushes guides the inner tube to facilitate the sliding motion over the outer tube. Typically, the outer tube having the pair of bushes is made of aluminum. A seal member held in position by a snap ring is assembled in the outer tube to avoid leakage of hydraulic fluid from the fork. Additional dust seal member is also used which prevents entry of foreign particles inside the fork and contamination of hydraulic fluid, thereby preventing damage to the seal member. Suspension assembly further consists of a spindle taper which generates required force during full stroke condition and prevents the inner tube assembly from bottoming.
[00022] Furthermore, the load carrying capacity of the suspension assembly can be increased by increasing any of the following characteristics, including, the length of the spring, the wire diameter, and pitch that has consequential impact on the length and outer diameter of the spring & often undesirable owing to the excess space it requires as well as adverse weight & cost impact..
[00023] Further, in state of art, the piston rod is supported on the hollow cylindrical portion present in the bottom axle bracket of the suspension assembly. As the bottom axle bracket has hollow cylindrical portion, it reduces the support from the bottom axle bracket to guide the piston rod thereby leading to tilting of piston rod which ultimately increases the friction in the suspension assembly since when the inner tube is in stroking mode, the piston rod slidably rubs against the inner tube of the suspension assembly.
[00024] Furthermore, with respect to the outer tube, a casted outer tube cannot be implemented in a layout of the vehicle which has low front axle width since it requires changes in the interfacing part to accommodate the addition of the material on the cast outer tube and requires additional fastener to mount the piston rod with the outer tube, which makes the system complex, increases number of parts, increases width of the vehicle at the front axle region as well as increase the cost of the vehicle.
[00025] Further, above layout vehicle may have the axle bracket member with a provision to enable mounting of the wheel axle and also, a provision to enable mounting of the piston. Additionally, a brake anchor is typically welded to the outer tube and another bracket attached to the outer tube for enabling mounting of the fender. In steel outer tube designs, the strength of the steel outer tube decreases due to the welding of the brake anchor and bracket.
[00026] Another way of providing a casted outer tube is where the main cylinder body and axle bracket are made an integral part of the outer tube. Although it is possible to integrate brake anchor and axle bracket to main body of outer tube but this has a process limitation. A thread is required to be drilled in the outer tube at axle bracket end which is difficult due to a constrain on the length of the outer tube. Increasing the length to incorporate a thread the bracket end will lead to increase in length of the fork assembly which adversely affect the handle bar height of the vehicle & thereby leading to unergonomic & undesirable layout of the vehicle.
[00027] Hence, there exists a challenge of designing an improved outer tube which can satisfactorily provide the support and guidance to the piston rod without any major change in design and manufacturing set-up of the vehicle overcoming all of the problems cited above & other problems of known art.
[00028] Hence, it becomes essential to provide a new design of an outer tube which has the mounting of bottom axle bracket, a projected portion to engagibly attach to the piston rod and also with a brake anchor which is integrated with it. The present invention provides a solution to the above problems while meeting the requirements of minimum modifications in the vehicle with ease of assembly etc.
[00029] With the above objectives in view, the present invention relates to the bottom axle bracket and more particularly to the improved mounting of bottom axle bracket with the outer tube where the outer tube is configured to be split & made up of two parts. The main cylinder body and the bottom axle bracket, where the bottom axle bracket has a provision for mounting both the axle mounting and brake anchor, thereby, increasing ease of assembly and reducing number of components.
[00030] As per one aspect of the present invention, the suspension assembly for a vehicle comprises a pair of front forks. The pair of front forks each comprises an outer tube and an inner tube slidably connected to at least one end of the outer tube. One end of the pair of front forks is mounted to a wheel axle and another end of the pair of front forks is attached to a bracket assembly. The bracket assembly is, for example, a lower bracket in scooter type vehicles and backbone frame type vehicles and motorcycles including both the lower brackets and the upper brackets holding the handlebar assembly. An elastic member is disposed inside the inner tube. The outer tube is connected to the wheel axle and the inner tube is connected to the handlebar assembly.
[00031] Further as per one aspect of present invention, the outer tube of the suspension assembly is divided into two parts namely the main cylinder body and the bottom axle bracket where the bottom axle bracket is detachably attached to the main cylinder body. Further, as per one embodiment the axle bracket is detachably attached to the main cylinder body by different attachment means like interference fit, the thread lock etc. Further, as per one aspect of the present invention, in the main cylinder body, the piston rod is disposed. Further, the piston rod having threaded portion conforms with the threaded portion of the projected portion present in the bottom axle bracket, thereby eliminating the need for additional fastener to hold the piston rod, thereby reducing the number of components.
[00032] Further, as per another aspect of the present invention, the bottom axle bracket is detachably attached to the main cylinder body. Further, the bottom axle bracket is divided into two parts namely, outer part and inner part where the inner part has a cylindrical threaded portion. Further, the piston rod which is disposed inside the main cylinder body, has a threaded profile which interlocks with the threaded profile of the cylindrical threaded portion present in the inner part of bottom axle bracket, thereby providing the support to piston rod which reduce the friction and improve the durability of the bottom axle bracket of the suspension assembly and also, eliminate the need for additional fastener to mount the piston rod with the bottom axle bracket.
[00033] Further, as per another aspect of the present invention, the bottom axle bracket is provided with a slot at the end, to support the one end of the wheel axle and another end of wheel axle is attached to the wheel of the vehicle. Further, the bottom axle bracket is provided with the brake anchor which is an integral part of the bottom axle bracket and the bottom axle bracket is manufactured by the different processes, for example: casting process, which ensures that the brake anchor strength is improved and hence, can bear higher braking loads acting on the fork. Further, as the load bearing capacity of the brake anchor increased , a material having comparatively lower strength than the material used in bottom axle bracket, can be used for casting main cylinder body of the outer tube, which makes the system light in weight as well as cost effective while maintaining the strength of the structure. Further, as per another aspect of the present invention, an sealing member which can be a rubber seal is disposed in between the bottom axle bracket and the main cylinder body, thereby ensuring adequate sealing of the joint and eliminating any leakage of the damping fluid thereat. Further, as per another aspect of the present invention, the bottom axle bracket can be detachably attached to the main cylinder body with the different attachment means e.g. bottom axle bracket is press fit against the main cylinder tube body and is coupled together with a grub screw, thereby ensuring rigid attachment of the axle bracket with the outer tube.
[00034] Various other features of the invention are described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number. With reference to the accompanying drawings, wherein the same reference numerals will be used to identify the same or similar elements throughout the several views.
[00035] In the ensuing exemplary aspects, the vehicle is a step through type vehicle. However, it is contemplated that the concepts of the present invention may be applied to any of the two wheeled vehicles without defeating the spirit of the invention.
[00036] Fig. 1 is a left side view of an exemplary two-wheeled step through type vehicle, in accordance with an embodiment of present subject matter. The vehicle (100) has a mono-tube type frame (101), which acts as the skeleton for bearing the loads and is also referred to as backbone frame as (shown in Fig 2). Instrument cluster (119) is mounted on handle bar assembly (126). The handle bar assembly (126) is pivotally disposed through the head tube where it includes brake levers (113). The handle bar assembly (126) is connected to a front wheel (129) by one or more suspension(s) assembly (130). The handle bar assembly (126) is connected to the front wheel (129) by using a pair of mounting brackets namely top mounting brackets (136) and lower mounting brackets (137). A front fender (131) is disposed above the front wheel (129) for covering at least a portion of the front wheel (129). A leg shield (112) is provided on the vehicle (100). A fuel tank (103) having fuel cap (114) is mounted to the main tube (101b) (as shown in Fig. 2) of the mono-tube type frame (101) and it is disposed in the front portion F of a step-through space of the mono-tube type frame (101). The vehicle (100) has lighting means which includes Head lamp (127), Tail lamp (106), Turning indicators which includes front side indicators (111) and rear side indicator (102) respectively and daytime running lamp (104). The power unit (125) is mounted to the lower portion of said mono-tube type frame (101). In an embodiment, the power unit (125) is an IC power unit. The fuel tank (103) is functionally connected to the power unit (125).
[00037] In an embodiment, cylinder axis (C-C’) inclined to a front of said vehicle (100) in a substantially forward rearward direction. A swing arm (134) is swingably connected to the mono-tube type frame (101). A rear wheel (133) is rotatably supported by the swing arm (134). One or more rear suspension(s) (135) connect the swing arm (134) at an angle, to sustain both the radial and axial forces occurring due to wheel reaction, to the mono-tube type frame (101). A license plate (105) and reflector (116) mounted on a rear fender (128) is disposed above the rear wheel (133). A seat assembly (132a, 132b) is disposed at a rear portion (R) of the step-through space. In an embodiment, the seat assembly (132) includes a rider seat (132a), and a pillion seat (132b). The vehicle (100) is provided with the grab rail (109). Further, the seat assembly (132a, 132b) is positioned above the rear wheel (133). The vehicle is supported by a center stand (120) mounted to the frame assembly. A tool box (110) is provided on the left side of said vehicle (100). A cover member (118) is mounted on down tube (101c) (as shown in Fig. 2). The cover member (118) covers at least a portion of the powerunit (125).
[00038] The powerunit (125) includes an, an air intake system (not shown), an exhaust system (not shown), and a starter system (not shown). The starter system includes an electric starter mechanism or a mechanical starter mechanism. The electrical starter system is powered by an auxiliary power source, for cranking the powerunit. Power generated by powerunit is transferred to the rear wheel (133) through a transmission system (not shown).
[00039] The powerunit (125) comprises a cylinder head (123), a cylinder (124) and a chain cover (121) in order from the front to the rear direction of a powerunit assembly (122). The cylinder (124) protrudes in a forward direction from the front-end portion.
[00040] Fig. 2 is a perspective view of the backbone frame structure which is generally of a convex shape, where main tube (101b) extending rearwardly and downwardly from a head tube (101a) of the mono-tube type frame (101), further a down tube (101c) of the mono-tube type frame (101) extends rearward forming a substantial floorboard space for utility & step through, along a longitudinal axis (L-L’) of the vehicle (100) from a rear portion of the main tube (101b).
[00041] The powerunit (125) (as shown in Fig. 1) is a four-stroke air-cooled powerunit where the center portion of the powerunit is supported to the mono-tube type frame (101) via a front bracket (204), and the rear portion thereof is supported by the rear bracket (202). Further, both front bracket (204) and rear bracket (202) brackets are positioned on the lower portion of the down tube (101c) when viewed from the left or right side of the vehicle (100).
[00042] The cover member (118) is disposed adjacent to the down tube (101c) using attaching means. The attaching means includes two floor mounting brackets (201) attached to the down tube (101c) of the mono-tube type frame (101) to support the cover member (118).
[00043] Fig. 3 is a sectional view of the suspension assembly as per one embodiment of the present invention. Further, as per one embodiment of the present invention, the suspension assembly (130) includes the pair of forks. Further, the suspension assembly also includes the outer tube (301 and inner tube (302) where one end of the inner tube is attached with the outer tube (301) and another end is attached with the handle bar assembly of the vehicle. Further, a damping fluid operates within the inner tube (302). The suspension assembly also includes a piston (303) including a piston rod (303a) having a piston head (303b) at one end, and a guide member (305. Further, a compression damping orifice (306, an extension damping orifice (307, a check valve (308), a compression chamber (309), an extension chamber (310 and a fluid reservoir (311 are also provided in the suspension assembly.
[00044] Typically, the suspension assembly works under the two strokes, namely, the compression stroke and the extension stroke, where during compression stroke, the suspension assembly (130) is in compressed state, therefore, the volume decreases in the compression chamber (309) and the volume increases in the extension chamber (310). As a result, the damping fluid present inside the compression chamber (309) is compressed and through the compression damping orifice (306), the damping fluid starts flowing to the extension chamber (310). The check valve (308) is open during the compression stroke and allows the flow of the damping fluid primarily from the compression chamber (309) into the extension chamber (310). Some amount of damping-fluid also reaches the fluid reservoir (311) during the compression stroke. Further, most of the damping fluid flowing into the fluid reservoir (311) gets accumulated in the guide member (305) disposed upon the piston rod (303a).
[00045] Moreover, during the extension stroke, when the suspension assembly is extended state, the area of the extension chamber (310) decreases. As per an aspect of the present invention, during extension stroke the damping fluid tries to escape to the compression chamber (309) from the extension chamber (310). The check valve (308) is closed during the working of the extension stroke, and hence the damping fluid has to escape to the compression chamber (309) through the extension orifice (307) located in the lower part of the piston (303) and present inside of the extension chamber (310). Therefore, the damping fluid flows from the extension chamber into the piston through the extension damping orifice, flows downwards and finally enters into the compression chamber through a relatively bigger compression damping orifice. Further, as per one embodiment of the present invention, the outer tube assembly (301) is divided into two parts namely bottom axle bracket (312) and main cylinder body (313), where the bottom axle bracket (312) is detachably attached to the main cylinder body (313) of suspension assembly.
[00046] Fig. 4 is an exploded perspective view of the main cylinder body with the bottom axle bracket as per one embodiment of the present invention. Further, as per one embodiment of the present invention, the bottom axle bracket (312) has a projected portion (401) integrally attached to the upper surface (402) of the bottom axle bracket (312), where the projected portion (401) has threading profile (403) on its surface (as shown in fig. 4a). Further, as per one embodiment of the present invention, the projected portion (401) is fixedly attached or integrated in the center of the upper surface (402) of the bottom axle bracket (312). The projected portion is disposed at an angle A with respect to the upper side (402) of the bottom axle bracket (312). Further, as per one embodiment of the present invention, the angle A is substantially orthogonal to the upper surface (402). Any major tilt in this angle can lead to tilting of the piston rod, ultimately increasing the friction in the inner tube. Further, as per one embodiment of the present invention, the piston rod (303a) is disposed inside the main cylinder body (313) and detachably attached to the bottom axle bracket (312).
[00047] Fig. 4b is a perspective view of the piston as per one embodiment of the present invention. Further, as per one embodiment of the present invention, the piston rod (303a) has a profile which has a threaded portion (404). The threaded portion (404) present in the profile engages in an interlocked manner with the threaded portion (403) present on the projected portion (401) of the bottom axle bracket (312), thereby ensuring the rigid attachment of the piston rod, eliminating the need of additional fastener to attach piston rod and also, increasing ease of assembly as here the projected portion acts as the guiding medium for piston rod and also provide support to the piston rod.
[00048] Fig. 5 is an exploded perspective view of main cylinder body with the bottom axle bracket. As per another embodiment of the present invention, the outer tube is divided into two parts that is main cylinder body (313) and bottom axle bracket (312), where the main cylinder body (313) has a depressed portion (502) which is detachably engaged to the bottom axle bracket (312) by various attachment means namely press fit, with the grub screw (504) to attach them rigidly. Further, as per another embodiment of the present invention, a sealing member (503) is disposed between the main cylinder body (313) and the bottom axle bracket (312), thereby restricting the leakage of the damping fluid. Further, as per another embodiment of the present invention, fender assembly is mounted by a fender assembly bracket (501) and clamped to the main cylinder body (313) via screw (504), which ensures the rigid mounting of the fender assembly.
[00049] Fig. 5a is a front view of the bottom axle bracket with the brake anchor as per another embodiment of the present invention. Further, as per another embodiment of the present invention, the brake anchor (505) is fixedly attached to the bottom axle bracket (312) the profile of which conforms with the engaging counterpart profile provided on the brake hub. Further, as per another embodiment, the brake anchor (505) is made integral with the bottom axle bracket (312) and the bottom axle bracket (312) is manufactured through casting process, thereby increase the strength and also, can take large braking loads acting on the forks of the suspension assembly. Further, as per another embodiment of the present invention, the bottom axle bracket has an opening (506) to accommodate wheel axle, thereby ensuring the attachment of outer tube with the wheel axle.
[00050] Fig. 5b is the inclined perspective view of the bottom axle bracket with a threaded portion and piston rod with a threaded portion. As per another embodiment of the present invention, the bottom axle bracket has two portions namely, outer region (508) and inner region (509), where the inner region (509) has a cylindrical threaded opening (507). The cylindrical threaded opening (507) has an outer diameter D. As per an embodiment, the outer diameter D is in range of 5-15mm. More than 15mm will also increase the diameter of the piston rod, which adversely affects the attachment of the piston rod with the bottom axle bracket & eats away into valuable space for the damping fluid leading to poor damping performance of the suspension as well as it increases the width of the axle support opening (506) leading to undesirable increase in lateral width dimension at the axle region. Further, diameter less that 5mm will lead to decrease the width of the piston rod which adversely affects the strength, perpendicularity geometry and assembly of the piston rod with the bottom axle bracket. Further, as per an aspect of this additional embodiment of the present invention, the piston rod has depressed portion (511) having threaded portion (510), where the piston rod is detachably attached to the cylindrical threaded opening (507) of the bottom axle bracket thereby, the cylindrical threaded portion act as the guiding and attaching member for the piston rod and also, eliminates the need of additional fastener to mount the piston rod with the axle bracket.
[00051] Further, as the outer tube is made into two parts that is main cylinder body (313) and the bottom axle bracket (312), thereby, it enables use of relatively lower strength material for the main cylinder body where the loads are much lower as compared to the axle bracket with brake anchor which experience large breaking loads, thereby making it cost effective and provides adequate structural strength.
[00052] The invention helps in overcoming the problem of use of additional fastener to attach the piston with the axle bracket ultimately increasing the strength of the axle bracket while ensuring the original layout of the vehicle
[00053] Advantageously, the embodiments of the present invention, describes the potential modifications in the assembly of the piston rod with the axle bracket. Also, brake anchor being an integral part of the axle bracket. This facilitates the simple and easy assembly of the piston with the axle bracket and also easy engagement of the brake hub with brake anchor which efficiently increases the ease of assembly and structural strength of the bracket.
[00054] Many other improvements and modifications like using different elastic means having stiffness may be incorporated herein without deviating from the scope of the invention.
List of reference symbol:
Fig. 1:
100: Step Through Vehicle.
126: Handle Bar Assembly
119: Instrument Cluster
127: Head Lamp
111: Front Side Indicator
104: Daytime Running Lamp
112: A leg Shield
131: A front Fender
129: Front Wheel
130: Suspension
113: Brake Lever
103: Fuel Tank
114: Fuel cap
118: Cover Member
123: Cylinder Head
124: Cylinder
122: Power unit Assembly
125: Power unit
132 (132a, 132b): Seat Assembly
101: Mono tube frame
109: Grab Rail
106: Tail Lamp
105: License Plate
102: Rear Side Indicator
128: Rear Fender
116: Reflector
135: Rear Suspension
133: Rear Wheel
134: Swing Arm
121: Chain Cover
120: Center Stand
110: Tool Box
C-C’: Cylinder Axis
136: Top Mounting Bracket
137: Lower Mounting Bracket
Fig. 2:
101: Mono Tube Type Frame
101a: Head Tube
101b: Main Tube
101c: Down tube
201: Floor Mounting Brackets
202: Rear Bracket
204: Front Bracket
Fig. 3:
301: Outer Tube
302: Inner Tube:
303: Piston
303a: Piston Rod
303b: Piston Head
305: Guide member
306: Compression Damping Orifice
307: Extension Orifice
308: Check Valve
309: Compression Chamber
310: Extension Chamber
311: Fuel Reservoir
312: Main cylinder Body.
313: Bottom Axle Bracket
Fig. 4
401: Projected Portion
Fig. 4a
402: Upper Part
403: Threaded Portion
A: Angle with respect to the upper part of bottom axle bracket.
Fig. 4b
404: Threading
Fig. 5
501: Fender Bracket
502: Depressed Portion
503: Rubber Seal
504: Grub Screw
506: Slot
Fig. 5a:
505: Brake Anchor
Fig. 5b
507: Cylindrical threaded portion
508: Outer Part
509: Inner Part
D: Diameter
511: Depressed Portion
510: Threaded Portion.