[0001] The present subject matter relates to a saddle type vehicle. More
particularly, the. present subject matter relates to a vehicle transmission system and alignment method therefor.
BACKGROUND
[0002] In a known scooter-type two- and three wheeled vehicle, a swing arm
is pivotably joumaled to a body frame with a pivot member and a rear wheel is rotatably mounted to the swing arm. A vehicle transmission system comprises an internal combustion engine configured to deliver power to the rear wheel. The engine is mounted on the swing arm through one or more mounting bosses and drivingly connected to the rear wheel via a transmission member. The engine includes a crankshaft or an output shaft configured to rotate. Further, the transmission system comprises a drive member mounted to the output shaft for rotation therewith and a driven member connected to the rear wheel. The transmission member such as a chain or the belt couples the drive and driven member, such that rotation of the output shaft is transmitted to the driven member and the rear wheel. The torque from the engine is transferred to the drive member, which in turn transfer the torque to the driven member through the transmission member.
BRIEF DESCRJPTION 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.l is a side view of a scooter type two-wheeled vehicle as per one
embodiment of the present invention.
[0005] Fig.2 is a top view of at least a rear portion of the scooter type two-
wheeled vehicle illustrating mounting of an engine on a vehicle swing arm, as per one embodiment of the present invention.

[0006] Fig. 3 is a top view of at least a rear portion of the vehicle of Fig.l
illustrating a transmission system for the vehicle, as per one embodiment of the present invention.
[0007] Fig.4 is an exploded view of said at least a rear portion of the vehicle
illustrating the mounting of the engine to at least a portion of the swing arm, as per one embodiment of the present invention.
[0008] Fig.5 is an exploded view of said at least a rear portion of the vehicle
illustrating one or more mounting portions being integrally formed with said at least a portion of an engine crankcase assembly, as per one embodiment of the present invention
DETAILED DESCRIPTION
[0009] In an existing scooter type two-and three wheeled vehicle, a swing arm
acts as a load carrying member and mounting for an internal combustion engine.
The swing-arm-is furmer-operationally-ehgagXd^im-aird supports a rear wheel to
adjust and align a chain or belt with respect to the swing arm. Typically, said engine is detachably secured to at least a portion of the swing arm through at most two mounting members integrally formed with.at least a portion thereof.
[00010] In a known saddle type vehicle, a transmission member including the belt or the chain is coupled between a drive member of an output shaft of the engine and a driven member of the rear wheel. However, since the engine is mounted on the swing arm with said at most two mounting members, thus when the vehicle is operated, the rear wheel is vibrated according to the conditions of the road surface, and the vibration transmitted from the rear wheel to the engine through the swing arm potentially results in a positional misalignment of the engine on the swing arm. Thus, the transmission member coupled between the drive member and the driven member and aligned with respect to said drive and driven member, tends to be twisted or distorted, putting undue stresses on the surfaces of the drive and driven members. Thus, due to wear and damages in said transmission member.arising out

of the above problem, the efficiency in the transmission system for the vehicle is reduced.
[00011] In another known saddle type vehicle, the engine adapted for delivering power to said rear wheel through the transmission member is mounted to said swing arm through two mounting portions. Thus, during periods of rapid acceleration and deceleration, the alignment of the transmission member including the belt- or chain changes dramatically. As a result, during operation of the engine, the transmission member including the belt generates a substantial amount of tension which reacts to certain sensed conditions that indicate a- potential for, or occurrence of, belt slip, which may be detrimental to the belt.
[00012] Thus, problem arises with the existing transmission system, when the
vehicle layout must accommodate the engine on said swing arm, a transmission member including a belt or chain being coupled between the drive and the driven member. In such layout, said engine and said drive and driven member of the transmission system must be maintained in the precise geometric positional relationship with respect to one another to avoid mechanical wear and failure of the transmission system.
[00013] Hence, it is desirable to provide an improved mounting mechanism for the engine on the swing arm of the scooter type saddle type vehicle for securing said engine to the swing and thereby minimize the impact on the transmission member resulting from engine positional misalignment and variations during operation. Further, it is desirable to provide an improved transmission system for the vehicle in which said transmission member coupled between the drive member and the driven member is aligned optimally with precise alignment of its geometry, thereby providing an efficient transmission system.
[00014] With the above objectives in view, the present invention provides an
improved transmission system which includes a modified mounting mechanism for removably mounting said engine to said swing arm of the scooter type saddle type vehicle such that an alignment of the engine, the drive and driven member and the

[00015] According to one embodiment, the scooter type saddle type vehicle comprises a swing arm adapted to support a rear wheel, said swing arm includes one or more mounting bosses fixedly attached to at least a portion thereof, a transmission system including an internal combustion engine configured to deliver power to the rear wheel. In one embodiment, said engine mounted to said swing arm through said one or more mounting bosses. Further, the transmission system comprises a drive member mounted to an output shaft of said engine, a driven member connected to the rear wheel, and a transmission member coupled between the drive member and the driven member. As per one embodiment, a pair of mounting bosses of said one or more mounting bosses are coaxially aligned with each other such-that the drive member and the driven member are in a same plane of symmetry and substantially equidistant from a longitudinal centerline axis of the vehicle.
[00016] Further, referring to one embodiment, said swing arm. comprises a pair of lateral support portions surrounding the pivot shaft, a first arm portion extending rearwardly from one lateral support portion of the pair of lateral support portions to a position along one lateral side of the rear wheel, a second arm portion extending rearwardly from other lateral support portion of the pair of lateral support portions to a position along other lateral side of the rear wheel, a cross-portion extending in the widthwise direction of the vehicle in order to connect the first arm portion to the second arm portion and further said at least one cross-member extending between said first arm portion and said second arm portion. Particularly, as per one embodiment, said pair of mounting bosses of said one or more mounting bosses are detachably secured to at least a portion of said first arm portion of the swing arm.
[00017] Further, as per one embodiment, the transmission member is optimally
aligned to maintain a constant relative orientation with respect to said drive member
and the driven member. Referring to one embodiment, one or more mounting
portions integrally formed to at least a portion of the engine corresponds to said pair
of mounting bosses. In one embodiment, said one or more mounting portions
includes at least one dowel pin. Further, said pair of mounting bosses are configured
to receive said at least one Hnwel nin f™- H^f-h^hi,, <.«.„»;— „„:,) -_^ •.,

swing arm. In one embodiment, said driven member are pulleys. In another embodiment, said drive member and said driven member are sprockets. As per one embodiment, said transmission member is a chain. In another embodiment, said transmission member is a drive belt.
[00018] Furthermore, said one embodiment of the present invention includes a method of aligning a transmission system on the scooter type saddle type vehicle. In one embodiment, said method comprises the steps of providing said one or more mounting bosses to said at least a portion of the swing arm by welding, providing said one or more mounting portion on said at least a portion of the engine by welding, mounting said engine to said swing arm through said one or more mounting bosses and said one or more mounting portions, mounting a drive member to an output shaft of the engine and connecting a driven member to a rear wheel, and coupling a transmission member between the drive member and the driven member. As per one embodiment, said method further comprises the step of aligning position of said drive member and said driven member at equidistance from a longitudinal centreline- axis of the vehicle to maintain a constant relative orientation of said transmission member, by maintaining a coaxial alignment of a pair of mounting bosses of said one or more mounting bosses.
[00019] The present invention relates to an alignment of the transmission member with respect to the drive and driven member for the vehicle transmission system. In one embodiment, the provision of said pair.of mounting bosses coaxially aligned with each other on said first arm of the swing arm facilitates in fixed orientation of said engine on said at least a portion of the swing arm in a front-rear direction of the vehicle, such that the transmission member including the belt is properly aligned between the drive member and driven member, thereby preventing any damage to the drive belt.
[00020] 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. 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. It should be noted that the drawings should be viewed in the direction of orientation of the reference numerals.
[00021] 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 hybrid two wheeled ' scooter type vehicle.
[00022] 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 two-wheeled vehicle. Furthermore, a longitudinal axis refers to a front to rear axis relative to the vehicle, while a lateral axis refers to a side to side, or left to right axis relative to the 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.
[00023] With reference to Fig.l, a description is made of a hybrid two wheeled scooter type vehicle (1) (hereinafter "vehicle") in accordance with one embodiment of the present invention. In one embodiment, said vehicle (1) illustrated, has a step-through type frame assembly (not shown) extending from a front portion (F) to a rear portion (R) along the vehicle longitudinal direction (AA»). The vehicle (1) includes a plurality of body panels for covering the frame assembly and is mounted thereto. In one embodiment, said plurality of body panels includes a front panel (6), a leg shield (25), an under-seat cover (23), and a left and a right side panel (13). Further, a glove box may be mounted to said leg shield (25). In a step through space formed between said leg shield (25) and said under seat cover (23), a floorboard (11) is provided. Further, a seat assembly (12) is disposed above said under-seat cover (23), and is mounted to the frame assembly (not shown). A utility box (not shown) is disposed below the seat assembly (12). A fuel tank (not shown) is positioned below the utility box. A pillion handle (14) is disposed behind said seat assembly (12). A front fender (5) is disposed above a front wheel (20) and between

left and right suspensions (4) supporting the front wheel (20). A rear fender (16)for covering at least a portion of the rear wheel (17) is positioned below the fuel tank. One or more suspension(s)/shock absorbers (19) are provided in the rear portion (R) of said vehicle (1) for comfortable ride. Further, said vehicle (1) comprises of plurality of electrical and electronic components including a headlight (7), a taillight (15), a transistor controlled ignition (TCI) unit (not shown), a starter motor (not shown) and the like. A touch screen LCD unit (not shown) is provided on a handle bar (9) to display various operating modes, power flow partem and warning signals. Rear view mirrors (8) are mounted on the right and left sides of the handle bar (9). In one embodiment, said vehicle (1) is also provided with hazard lamps (not shown).
[00024] Further in Fig.l, as per one embodiment, said vehicle (1) includes a swing arm (22) adapted to support the rear wheel (17) and pivotably rotate about an axis on the frame structure. In one embodiment, a transmission system. (200) includes an internal combustion engine (24) configured to deliver power to the rear wheel (17). The engine (24) is removably mounted to said swing arm (22). The rear wheel (17) and the swing arm (22) are connected to at least a rear frame portion by means of a pair of shock absorbers (19) provided on either side of the vehicle (1). Further, said vehicle (1) includes an electric motor (18) mounted on a hub of the rear wheel (17). In one embodiment, said electric motor (18) is powered by the engine (24) to deliver driving force to the vehicle (1). A controller (not shown) is also provided to control various vehicle operative modes. Referring to one embodiment of the present invention, the vehicle (1) is configured to be propelled either by the engine (24) alone or by the electric motor (18) alone or by both engine (24) and the electric motor (18) simultaneously. At zero vehicle speed, a rider can select any of the following four operating drive modes with the help of a mode switch. The four operating drive modes of the vehicle (1) are: (a) a sole engine mode where engine (24) alone powers the vehicle (1), (b) a sole motor mode where the electric motor (18) alone powers the vehicle (1), (c) a hybrid power mode wherein the engine (24) and the electric motor (18) together power the hybrid vehicle (1), (d) a hybrid economy mode wherein only the engine (24) or onlv the

electric motor(18) or both power the hybrid vehicle (1) depending on the vehicle operating conditions. In other words, the rear wheel (17) of the vehicle (1) is driven by either the engine (24) alone or by the motor (18) alone or by both the engine (24) and the motor (18) simultaneously. Particularly, power from the engine (24) to the rear wheel (17) is transmitted by a transmission system (200), as per an embodiment of the present invention.
[00025] Fig 2. is a top view of at least a rear portion of the vehicle (1) illustrating the mounting of said engine (24) on said at least a portion of the swing arm (22) through said one or more mounting bosses (201), (202), (203), (204), as per one embodiment of the present invention. As per one embodiment, said swing arm (22) adapted to support the rear wheel (17) includes said one or more mounting bosses (201), (202), (203), (204) fixedly attached to at least a portion thereof. In one embodiment, said vehicle transmission system (200) includes said engine (24) mounted to said swirig arm (22) through said one or more mounting bosses (201), (202), (203), (204), the drive member (29) mounted to the output shaft of said engine (24), the driven member (28) connected to the rear wheel (17) and the transmission member (21) coupled between the drive member (29) and the driven member (28). In one embodiment, said drive member (29) and said driven member
(28) are pulleys. In another embodiment said drive member (29) and said driven
member (28) are sprockets. As per one embodiment, said transmission member (21)
is drive belt. In another embodiment of the present invention, said transmission
member (21) is a drive belt.
• [00026] Fig. 3 and Fig.4 are top views of said at least a rear portion of the vehicle (1) illustrating the transmission system (200) for the vehicle (1), as per one embodiment of the present invention. In one embodiment, said vehicle transmission system (200) includes the engine (24) configured to deliver power to the rear wheel (17). In one embodiment, said engine (24) is mounted to said swing arm (22) through said one or more mounting bosses (201), (202), (203), (204) (shown in Fig.4 and Fig.5). Further, said transmission system (200) includes the drive member
(29) mounted to the output shaft of said engine (24), the driven member (28)

connected to the rear wheel (17) and the transmission member (21) coupled between the drive member (29) and the driven member (28).As per one embodiment, said pair of mounting bosses (202), (203) of said one or more mounting bosses (201), (202), (203), (204) are coaxially aligned with each other such that the drive member (29) and the driven member (28) are in the same plane of symmetry and substantially equidistant (D) from said longitudinal centerline axis (XX') of the vehicle (1). "
[00027] Fig.5 is an exploded view of said at least a rear .portion of the vehicle
illustrating the mounting of the engine (24) to said at least a portion of the swing
arm (22), as per one embodiment of the present invention. In one embodiment, said
swing arm (22) adapted to support the rear wheel (17) comprises said pair of lateral
support portions (28a), (28b) surrounding the pivot shaft (28), the first arm portion
(22a) extending rearwardly from one lateral support portion (28a) of the pair of
lateral support portions (28a), (28b), to a position along one lateral side of the rear
wheel (17), the second arm portion (22h) extending rearwardly from other lateral !
support portion (28b) of the pair of lateral support portions (28a), (28b); to a
position along other lateral side of the rear wheel (17), a non-planar cross-portion
(22c) extending in the widthwise direction of the vehicle (1) in order to connect the
first arm portion (22a) to the second arm portion (22b) and further said at least one
cross-member (22d) extends between said first arm portion (22a) and said second
arm portion (22b).
[00028] Further in Fig.5, referring to one embodiment, said one or more mounting bosses (201), (202), (203), (204) being fixedly attached to at least a portion of the swing arm (22) are configured for mounting said engine (24) to the swing arm (22). As per one embodiment, said pair of mounting bosses (202), (203) of said one or more mounting bosses (202), (203) being fixedly attached to the first arm (22a) of the swing arm (22) are coaxially aligned with each other. Further, at least one mounting boss (201), (204) includes a first mounting boss (201) and a second mounting boss (204), being fixedly attached to said cross-member (22d) and said non-planar cross-portion (22c) of the swing arm (22), respectively. In one

embodiment, said first mounting boss (201) is configured to receive said one or ■ more mounting elements (201b), (201c), said second mounting boss (204) is adapted to receive one or more mounting members (204a), (204b) and said pair of mounting bosses (202), (203) are adapted to receive at least one engine integral dowel pin (205), (206) (shown in Fig.6). Thus, said pair of said mounting bosses (202), (203) and said at least one mounting boss (201), (204) of said one or more mounting bosses (201), (202), (203), (204) are adapted for detachably securing said engine (24) on said swing arm (22) of the vehicle (1). This configuration of the mounting scheme also enables ease of assembly of the power train onto the vehicle as well as during service.
[00029] Fig.6 is an exploded view of said at least a rear portion of the vehicle (1) illustrating said one or more mounting portions (205), (206) being integrally formed with said at least a portion of the engine crankcase assembly (29), as per embodiment of the present invention. As per one embodiment, said engine (24) includes the crankcase assembly (29) divided into, a left crankcase half (29L) and a right crankcase half (29R). In one embodiment, said one or more mounting portions (205), (206) including at least one dowel pin is integrally formed to a lateral end of the bottom surface (27) of the left crankcase half (29L), such that said pair of mounting bosses (202), (203) fixedly attached to said first arm (22a) of the swing arm (22) and coaxially aligned with each other and are configured to receive said at least one dowel pin of said one or more mounting portions (205), (206) for detachably securing said engine (24) on at least a portion of the vehicle (1).
[00030] It is advantageous to provide an improved mounting mechanism for detachably securing said engine on said at least a portion of the scooter type two-wheeled which provides the benefits of vibration control and the drive belt reliability of optimally aligned transmission system such that one or more operational characteristics of the vehicle through a proper alignment of the drive belt coupled between the drive member and the driven member of the transmission * system is substantially enhanced. Furthermore, advantageously, with said provision of said at least one mounting mechanism, the engine is detachably secured to the

swing arm by rigid mounting. Thus, such rigid mounting of the engine on the swing arm provides a more definite placement and geometric accuracy of said transmission member between said drive member and the driven member during operation, and in addition, the vibration transferred from the rear wheel to the engine is reduced.
[00031] Improvements and modifications may be incorporated herein without deviating from the scope of the invention.

We Claim:
1. A saddle type vehicle (1), said vehicle (1) comprising:
a swing arm (22) adapted to support a rear wheel (17), said swing arm (22)
includes one or more mounting bosses (201), (202), (203), (204) fixedly
attached to at least a portion thereof; •
a transmission system (200) including an internal combustion engine (24)
configured to deliver power to the rear wheel (17), said engine (24)
mounted to said swing arm (22) through said one or more mounting bosses
(201), (202), (203), (204);
a drive member (29) mounted to an output shaft of said engine (24),
a driven member (28) connected to the rear wheel (17), and
a transmission member (21) coupled between the drive member (29) and
the driven member (28);
wherein a pair of mounting bosses (202), (203) of said one or more
mounting bosses (201), (202), (203), (204) are coaxiaUy aligned with each
other such that the drive member (29) and the driven member (28) are in a
same plane of symmetry and substantially equidistant from a longitudinal ■
centreline axis (XX') of the vehicle (1).
2. The saddle type vehicle (1) as claimed in claim 1, wherein the transmission member (21) is configured to have precise geometric alignment to maintain a constant relative orientation with respect to said drive member (29) and the driven member (28).
3. The saddle type vehicle (1) as claimed in claim 1, wherein said pair of mounting bosses (202), (203) are configured to receive one or more engine mounting portions (205), (206) for detachably securing said engine (24) on said swing arm (22).
4. The saddle type vehicle (1) as claimed in claim 1, wherein at least one mounting boss (201), (204) includes a first mounting boss (201) and a second mounting boss (204), being fixedly attached to said cross-member (22d) and said non-planar cross-portion (22c) of the swing arm (22), respectively

5. A method of aligning a transmission system (200) of a saddle type vehicle (1); said method comprising the steps of:
mounting said engine (24) to said swing arm (22) through said one or more mounting bosses (201), (202), (203), (204) and said one or more mounting portions (205), (206);
mounting a drive member (29) to an output shaft of the engine (24) and connecting a driven member (28) to a rear wheel (17); coupling a transmission member (21) between the drive member (29) and the driven member (28); and
aligning position of said drive member (29) and said driven member (28) at an equidistance from a longitudinal centreline axis OCX*) of the vehicle (1) to maintain a constant relative orientation of said transmission member (21), by maintaining a coaxial alignment of a pair of mounting bosses of said one or more mounting bosses (201), (202), (203),- (204).