DESC:TECHNICAL FIELD
[0001] The present subject matter relates to a saddle type vehicle. More particularly, the present subject matter relates to a rear suspension system for the saddle type vehicle.
BACKGROUND
[0002] Conventionally, a suspension system of saddle type vehicles including two-wheeled saddle type vehicles serves to improve the safety of the vehicle while also contributing to improve drive comfort by isolating the rider from road bumps, vibrations, etc. Typically, a rear suspension system generally falls into one of two categories: a ‘dual shock’ suspension system that uses two shocks or a ‘monoshock’ system which uses a single shock absorber. A monoshock is typically mounted in line with a central plane of the vehicle and can be oriented in several different positions within that plane. The selection and configuration of the rear suspension system depends heavily on the intended use of the vehicle, as well as its weight and dimensions. Independent of application, monoshock systems have some advantages over dual shock systems, such as lower weight and more consistent tuning. Since the shock absorber in a saddle type vehicle is an important component impacting the performance of the vehicle as well as for determining the comfort for the rider, the kinematic layout of the shock absorber & balance of its dynamic forces are critical for good performance of the vehicle. Therefore, there is a need to have an overall optimum vehicle layout including layout of the rear shock absorber so as to have a good balance or equilibrium of the dynamic forces acting on the structural portion of the vehicle. The mounting position of the shock absorber end pivots, the angle of the shock absorber as well as the disposition of the system in vehicle layout is critical. Also, the conventional mounting of monoshock in saddle type vehicles is vertical and much closer to center of rear wheel. This layout of the monoshock system affects the space available for accommodating a utility box below a seat assembly of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0004] Fig.1 illustrates a side view of a saddle type vehicle including a rear suspension system in accordance with an embodiment of the present invention.
[0005] Fig.2 illustrates a perspective view of a rear portion of the vehicle including a monoshock suspension system in accordance with one embodiment of the present invention.
[0006] Fig.3 illustrates a right side view of a rear portion of the vehicle including a monoshock suspension system in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
[0007] A saddle type vehicle exemplified herein is a two-wheeled vehicle comprising a frame structure including a head tube, a main frame member extending rearwardly from the head tube, a lower frame member extending obliquely downwardly and comprising a floor frame adapted to support floorboard. In one embodiment, a vehicle body cover is configured for covering said frame structure. The vehicle body cover includes a front body cover covering a front portion of the vehicle and a rear body cover covering a rear portion of the vehicle. Referring to one embodiment, said front body cover includes a front covering member and a rear covering member. In one embodiment said front covering member is separated from the rear covering member through a gap portion. In one embodiment, said rear body cover includes a pair of left and right side covers and a top cover. In one embodiment, a pair of left and right lid members is formed in at least a portion of each of said pair of left and right side covers Further, as per one embodiment, said saddle type vehicle comprises one or more batteries adapted for powering an electric motor for providing driving force to the vehicle. In one embodiment, said electric motor disposed on a rear portion of the vehicle is configured for transferring drive force to said rear wheel through a transmission assembly. In one embodiment, said transmission assembly comprises a transmission case having a transmission cover and a drive member including a belt and chain. In one embodiment, one or more components of the transmission assembly is held within the transmission cover of the transmission assembly.
[0008] In one embodiment, a rear suspension system of the vehicle comprises a monoshock suspension system comprising a single shock absorber and a spring unit. As per one embodiment, an upper end of said suspension system is connected to at least a portion of said upper frame and a lower end of said suspension system is detachably secured to said transmission case through at least one bracket member integrally formed therein. In one embodiment, said at least one bracket member is fixedly attached to said at least a portion of the transmission case and is adapted for securing said rear suspension system including shock absorber and spring unit to the vehicle.
[0009] The present invention provides an improved rear suspension system for the saddle type two-wheeled vehicle. As per one embodiment, said rear suspension system is constituted by a monoshock suspension system including a single shock absorber and spring unit. As per on embodiment, an upper end of said single shock absorber and spring unit is connected to a portion of the main frame member and a lower end of said shock absorber and spring unit is detachably secured to a transmission case of a transmission assembly through at least one bracket member such that said monoshock system is offset with respect to a lateral center of said vehicle and aligned with a portion of a main frame member of the vehicle frame structure, thereby facilitating a provision of mounting of an increased capacity storage box below a seat assembly of the vehicle. Furthermore, it is advantageous to detachably mount said monoshock suspension system on the vehicle such that said shock absorber and spring unit can be assembled and dissembled without dissembling any other vehicle components, thereby providing reduced assembling time for mounting said rear suspension system on the vehicle.
[00010] In one embodiment of the present invention, said monoshock system uses one shock, which is oriented offset with respect to lateral center of the vehicle and aligned with the frame structure. Furthermore, said improved rear suspension system constituted by said monoshock suspension system imparts lower weight and more consistent tuning due to having only one shock instead of two.
[00011] Various other features and advantages 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. 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. It should be noted that the drawings should be viewed in the direction of orientation of the reference numerals.
[00012] It is to be noted that in the ensuing description, the present invention is usable in a saddle type vehicle exemplified in the form of a electric two-wheeled vehicle. It is to be noted that in the ensuing description, the present invention is used in a saddle type vehicle exemplified in the form of an electric two-wheeled vehicle. However, the present application is also applicable to other saddle type two-wheeled and three-wheeled vehicles where a monoshock suspension is used.
[00013] Further “front” and “rear”, and “left” and “right” referred to in the ensuing description of the illustrated embodiment refer to front and rear, and left and right directions as seen in a state of being seated on a seat of the saddle type two-wheeled vehicle. Furthermore, a longitudinal axis refers to a front to rear axis relative to said vehicle, while a lateral axis refers to a side to side, or left to right axis relative to said vehicle. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
[00014] With reference to Fig.1, an exemplary description is made for a saddle type vehicle (100) (hereinafter “vehicle”), specifically for an electric two-wheeled saddle type vehicle in accordance with an embodiment of the present invention. In one embodiment, said vehicle (100) comprises a frame structure (119) extending from a front portion (F) to rear portion (R) of the vehicle in a vehicle longitudinal direction (A-A). Said frame structure (119) includes a head tube (not shown), a main frame member (118) extending rearwardly from the head tube, a lower frame member (not shown) extending obliquely downwardly and comprising a floor frame adapted to support a floorboard (117). Further, said vehicle includes a vehicle body cover (101) which is adapted for covering said frame structure (119). The vehicle body cover (101) includes a front body cover (109) covering the front portion of frame structure and a rear body cover (105) covering at least a portion of the lower frame member.
[00015] Particularly, as per an embodiment said front body cover (109) includes a front covering member (102) and a rear covering member (110). In one embodiment, said rear body cover (105) includes a pair of left and right side covers (105L), (105R) (the right side cover is symmetrical to the left side cover and hence not shown) and a top cover (not shown). Particularly, each side cover of said pair of left and right side covers (105L), (105R) is respectively provided with a lid member each (108L), (108R). In one embodiment, each lid member (108L), (108R) is pivotally attached to said at least a portion of said pair of left and right side covers (105L), (105R). Further, a seat assembly (113) is mounted to the main frame member (118) in the rear portion (R) of the vehicle (100). The seat assembly (113) includes a rider seat (113a) and a pillion seat (113b) A utility box (not shown) is disposed below the seat assembly (113). A front fender (103) is disposed above a front wheel (104) and between left and right suspensions supporting the front wheel (104). A rear fender (114) is adapted for covering at least a portion of a rear wheel (115). The rear wheel (115) is driven by an electric motor (202) which is connected to a transmission assembly having a transmission case (116) and a transmission cover (112). As per an aspect of the present subject matter, a rear suspension system (200) constituted by a monoshock suspension system comprising a shock absorber and a spring unit (201) is disposed behind said main frame member (118) and above the transmission assembly comprising said transmission cover (112) and said transmission case (116).
[00016] As per an aspect of the present invention, said shock absorber (201) is so disposed to make an angle (Ø) of less than 45 degrees with a horizontal line B-B’ passing through arear wheel axis. Further, as per another aspect of the present invention, axis of said shock absorber (201) is substantially aligned to a portion of the main frame member (118) disposed ahead of said shock absorber. Particularly, the line A-A’ passing through the axis of the shock absorber is held to be substantially orthogonal to the head tube (not shown) of the vehicle. This orientation of the shock absorber especially for a case of monoshock suspension system, enables optimum distribution of the loads coming from the rear wheel (115) & road undulations so that the structure of the vehicle is intact, thereby improving robustness and durability of the vehicle. Further, this orientation of the monoshock suspension system ensures that a wheel force acts in a perpendicular direction of the shock absorber force which acts in a direction substantially parallel to the shock absorber about its top pivot point, thereby giving a balanced force equilibrium as the wheel travel force direction is maintained substantially parallel to the front suspension of the vehicle. As per another aspect of the present invention, the line A-A’ intersects the line B-B’ at a position substantially downstream of the rear wheel axis & substantially within the outermost boundary of the rear edge of the vehicle. As per another aspect of the present invention, a bottom mounting point of the monoshock rear suspension system is secured substantially in the middle portion of the transmission case (116) which enables even force distribution. Additionally, a top pivot point (shown in Fig.2) of the shock absorber and spring unit in the described layout of the vehicle is disposed substantially below the mid region of the rider seat & in close vicinity to the rider seat contact point of the vehicle.
[0001] Fig.2 & Fig.3 illustrate a rear portion of the vehicle (100) depicting a mounting of said rear suspension system (200) of the vehicle (100) as per an embodiment of the present subject matter. In the present embodiment, said rear suspension system (200) is a monoshock suspension system which comprises a single shock absorber and spring unit (201). As per one embodiment, an upper end of said shock absorber and spring unit (201) comprising a top pivot point (201t) (shown in Fig.1) is connected to at least a portion of said main frame member (118) and a lower end including the bottom mounting point (201b) (shown in Fig.3) of said shock absorber-spring unit (201) is detachably secured to said transmission case (116) through at least one bracket member (116b) integrally formed with said transmission case (116). In another embodiment, said at least one bracket member (116b) may be fixedly attached to said at least a portion of the transmission case (116) and be adapted for securing said rear suspension system (200) including shock absorber-spring unit (201) to the vehicle (100). Whereas a portion of said bracket member (116b) extends from a front top portion of said transmission case (116) for holding one end of a bottom mounting point (201b) of said shock absorber (201), a portion of said bracket member (116b) extends from a rear top portion of said transmission case (116) for holding another end of a bottom mounting point (201b) of said shock absorber (201). Particularly, said bottom pointing point (201b) of the shock absorber (201) is secured to portion of the bracket member (116b) which extends from said front top portion of said transmission case (116) is formed in a top middle portion of said transmission case (116). More particularly, said bracket member (116b) is positioned such that said bottom mounting point (201b) of said shock absorber (201) lies away from a midpoint of a line joining a motor center (Y) and a rear wheel center (X) (shown in Fig.1) and pointing towards said front wheel (104) of the vehicle. This ensures that the shock absorber is shorter and more horizontal as compared to a conventional monoshock absorber, resulting in the availability of more space for the accommodation of the utility box of the vehicle.
[0002] Improvements and modifications may be incorporated herein without deviating from the scope of the invention.
,CLAIMS:We Claim:
1. A rear suspension system (200) for a saddle type vehicle (100), comprising:
a frame structure including a head tube, a main frame member (118) extending rearwardly from said head tube, and a lower frame extending obliquely downwardly and comprising a floor frame;
a rear body cover (105) covering at least a portion of lower frame;
a floorboard (117) constituted by said floor frame and disposed below at least a portion of said rear body cover (105);
a transmission assembly comprising a transmission case (116) and a transmission cover (112) disposed behind said floorboard (117);
said rear suspension system being constituted by a monoshock suspension system (200); said monoshock suspension system comprising a single shock absorber and spring unit (201) is substantially aligned with a portion of said main frame member (118) of said saddle type vehicle with a bottom mounting point (201b) of said suspension being provided away from a midpoint of a line joining a rear wheel center (X) and a motor center (Y) and pointing towards a front wheel (104).
2. The rear suspension system (200) as claimed in claim 1, wherein said shock absorber and spring unit (201) has said bottom mounting point (201b) secured to a bracket member (116b) formed substantially in a top middle portion of the transmission case (116).
3. The rear suspension system (200) as claimed in claim 2, wherein said bracket member (116b) is formed integrally in the transmission case (116).
4. The rear suspension system (200) as claimed in claim 1, wherein said shock absorber and spring unit (201) has a top pivot point (201t) which is connected to at least a portion of said main frame member (118).
5. The rear suspension system (200) as claimed in claim 1, wherein said monoshock suspension system is offset with respect to a lateral center of said vehicle (100).
6. The rear suspension system (200) as claimed in claim 1, wherein said monoshock suspension system makes an angle of 45° with a horizontal line B-B’ passing through a wheel axis of a rear wheel (115) of said vehicle.
7. The rear suspension system (200) as claimed in claim 1, wherein said monoshock suspension system includes an axis through which a line A-A’ is made to pass, said line A-A’ being orthogonal to the head tube of said vehicle (100).
8. The rear suspension system (200) as claimed in claim 7, wherein said line A-A’ intersects a line B-B’ at a position substantially downstream of a rear wheel axis & substantially within an outermost boundary of a rear edge of the vehicle.
9. The rear suspension system (200) as claimed in claim 1, wherein said monoshock suspension system exerts force which acts in a direction substantially parallel to the shock absorber about its top pivot point (201t) and perpendicular to direction of wheel force.