FIELD OF THE INVENTION

[0001] The subject matter as described herein, relates generally to a two wheeled vehicle and more particularly, but not exclusively, to an air cleaner assembly for a scooter type motorcycle.

BACKGROUND OF THE INVENTION
[0002] Conventionally, a scooter type motorcycle is powered by an internal combustion engine disposed at a lower half of the motorcycle. Conventionally, such engine is provided with a CVT type transmission for easy and comfortable operation of the motorycle. The engine and the transmission are packaged in a long engine casing. A front portion of the engine casing is connected swingably to a front frame through a link mechanism and a rear portion of the engine casing is connected to a hub of the rear wheel. An air cleaner assembly is supported on such engine casing at two mounting points and swings with the engine.

[0003] However, to overcome the transmission losses by CVT, the engine is provided with a chain type transmission wherein the length of the engine reduces. In the engine with chain type transmisson, the engine is supported on a swing arm and chain type transmission connects the engine to the rear wheel. The mounting of the air cleaner assembly is thus difficult in a small length engine supported on the swing arm. Further, the positioning of air cleaner assembly in such construction is limited by space constraints and placement and packaging of the air cleaner assembly plays a key role.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The above and other features, aspects, and advantages of the subject matter will be better understood with regard to the following description and accompanying drawings where:

[0005] FIG. 1 is a side elevation view of a "scooter type motorcycle according to the present invention.

[0006] FIG. 2 shows a side view of a frame assembly of the naked motorcycle supporting an internal combustion engine and an air cleaner assembly.

[0007] FIG. 3 shows a rear perspective view of the assembly of the air cleaner assembly according to the present invention.

[0008] FIG. 4 shows a detailed side view of a naked rear portion of the motorcycle.

[0009] FIG. 5 shows a top view of the FIG. 2.

DETAILED DESCRIPTION
[00010] A scooter type motorcycle has a swinging engine casing housing an engine and a transmission. Conventionally, the transmission includes a continuously variable transmission (CVT) for ease of operation of the engine and better ride comfort. Usually, the engine casing is extended along the longitudinal axis of the motorcycle and supports an air cleaner assembly along its length. However, an AMT engine is provided with automatic gear shift and automatic clutch actuation. In such engine, the. CVT is replaced with a chain type transmission for reducing factional losses and hence the length of the engine casing reduces. Hence, it becomes disadvantageous to support the same air cleaner assembly on the casing of the AMT engine having reduced length. This is because the air cleaner assembly acts as an overhang on the engine casing because the length of the air cleaner assembly exceeds that of rear portion of the engine casing. Further, due to space constraints in the vehicle, the placement and packaging of the air cleaner assembly plays a key role in efficient performance of the motorcycle. It is also necessary to mount the air cleaner assembly close to a cylinder head of the engine for reduced suction loss and reduced pipe length. The centre of gravity of the motorcycle should not be affected to ensure ride comfort. The present invention disclosed herein is aimed at overcoming the challenges associated with the mounting of the air cleaner assembly in such vehicle configuration..

[00011] It is therefore an object of the present invention to provide a firm support to an air cleaner assembly in a scooter type motorcycle provided with a compact AMT engine having chain type transmission and fixedly supported on a swing.arm. It is another object of the present invention to mount the air cleaner assembly in such engine without disturbing the centre ..of gravity and without reducing the volume of the air cleaner assembly. It is another object of the present inventiont to package the air cleaner assembly proximately to an article container without compromising the article storage volume.

[00012] The present invention thus provides an air cleaner assembly positioned in the scooter type motorcycle having an AMT engine casing of reduced length. The air cleaner assembly is positioned between a crankshaft centre of the engine and a rotary centre of the rear wheel. More specifically, a front portion of the air cleaner assembly is supported on the engine casing between the crankshaft centre of the engine and a sprocket centre of the chain type transmission. A rear portion of the air cleaner assembly is supported on a rear frame, preferably swing arm, between the front most point of the rear wheel and the rotary centre of the rear wheel. The present invention achieves a firm mounting of the air cleaner assembly in a compact engine having chain type transmission fitted on a scooter type motorcycle.

[00013] The present subject matter and its embodiments would now be described in greater detail in conjunction with the figures in the following description. The following description provides a convenient illustration for implementing exemplary embodiments of the invention. 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 two wheeled scooter type motorcycle for illustration. However, the concepts disclosed in the present invention can be practiced in other two wheeled vehicles having similar configuration. 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 scooter type motorcycle. Furthermore, a longitudinal axis refers to a front to rear axis relative to the motorcycle, while a lateral axis refers to a side to side, or left to right axis relative to the motorcycle. 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. Various other features and embodiments of the present subject matter here will be discernible from the following further description thereof, set out hereunder. The detailed explanation of the constitution of parts other than the subject matter which constitutes an essential part has been omitted at suitable places.

[00014] FIG. 1 shows a side elevation view of the scooter type motorcycle (hereinafter 'motorcycle'). The motorcycle (1) includes a frame assembly made up of several tubes welded together supporting the body of said motorcycle (1). A lower half of the front portion of the motorcycle (1) has a steerable front wheel (2) and a driven rear wheel (4) driven by driving force generated by an IC engine (40). The rear wheel (4) is disposed behind the engine (40). The front wheel (2) of the motorcycle (1) is axially supported at a lower end of a front fork (3), and the front fork (3) is pivoted in a steerable manner in a head pipe (55) (FIG. 2) of the motorcycle frame.
[00015] The upper half of the front portion of the motorcycle (1) comprises of a handle bar (22) attached to an upper end of the head pipe (55). The handle bar (22) and a seat (12) are supported at opposing ends of the frame assembly and a generally open area is defined there between known as floorboard (9) which functions as a step through space. The seat (12) for a driver and a pillion is placed forward to a fuel tank and rearwardly of the floorboard (9). A side trim member (13) laterally beneath the floorboard (9) is provided to cover the lower frame members from being visible. The side trim member (13) is laterally present on both sides of the motorcycle (1); however, only one is visible in the side view. A side stand fixed to the left side of the frame supports the motorcycle (1) such that motorcycle (1) can incline to the left side without falling.

[00016] As further shown in FIG. 1, the vehicle frame assembly is covered by a plurality of motorcycle body covers including a front cover (16), a rear cover (21), an under seat cover (10), a left side cover (11), a right side cover and a bottom cover. The right side cover is symmetrical to the left side cover (11) and hence not shown. A front fender (17) is accommodated between the front cover (16) and the upper portion of the front wheel (2) to partially cover the front wheel (2). Likewise, the rear wheel (4) is covered by a rear fender. The rear cover (21) acts as a leg shield. The rear cover (21) is disposed below a headlamp unit (5), and is secured to and fixedly connected to the front cover (16). The headlamp unit (5) is arranged forwardly of the handle bar (22) and towards the upper end of. the steering tube. It is surrounded by a visor (6) from the front direction, and by a headlamp housing (20) from the rear direction. The headlamp housing (20) faces the vehicle rider and outlines the instrument cluster of the vehicle. It is detachably secured to the visor (6) from behind the headlamp unit (5). In said motorcycle (1), the engine (40) is configured to drive, and is supported on the vehicle frame assembly. In an embodiment of the present invention, the engine (40) is a four stroke single cylinder internal combustion engine.
[00017] FIG. 2 shows a side elevational view of the naked motorcycle (1) with the frame assembly. The frame assembly of the vehicle (1) is an elongated structure, which typically extends from a forward end to a rearward end of the vehicle (1). It is generally convex in shape, as viewed from a side elevational view. The vehicle frame assembly comprises of a front frame and a rear frame.
The front frame comprises of the head pipe (55), a downpipe (56) extending downwards from the head pipe (55) and a lower pipe (57) supporting the low- slung floorboard (9) extending rearwards from a lower end of the downpipe (56). The steering tube is disposed partially inside the head pipe (55). The rear frame of the vehicle comprises of a rear pipe (58) formed by curving a rear end section of the lower pipe (57) diagonally upwards. The rear pipe (58) forms a part of the rear frame of the vehicle and is made of an inclined section extending diagonally upwards from a rear end of the lower pipe (57), and a horizontal section extending rearwards substantially horizontally from the inclined section. The rear frame also comprises of a swing arm (30) for supporting the engine (40). The front portion of the swing arrir(30) is pivotally connected to the front frame; specifically the lower pipe (57), through a link mechanism and the rear portion of the swing arm (30) is fixedly, supported on the rear wheel (4). Thus, the swing arm (30) extends from the link mechanism to the rear wheel (4) of the vehicle and fixedly supports the engine (40). '.-.'.
[00018] The swing arm (30) further comprises of a first supporting tube (31) approximately parallel to the vehicle longitudinal axis, a second supporting tube (32) disposed angularly to and connected to the first supporting tube (31) and a cross tube (33) connecting the second supporting tube (32) on the first supporting tube (31). One end of the first supporting tube (31) and one end of the second supporting tube (32) converge at a rotary centre (P2) of the rear wheel (4), while the other ends are divergent to each other.

[00019] The engine (40) comprises of a cylinder head (41) and a crankcase (42) housing, among other things, a crankshaft and lubrication system of the engine (40). The engine (40) is initiated with the help of a starter motor (43) disposed above the crankcase (42). The crankshaft rotates along the crankshaft centre (PI). The crankshaft centre (PI) denotes the long axis.of the crankshaft about which it rotates as seen in the side view of the motorcycle (1). The cylinder head (41) is connected to the crankcase (42) and disposed forwardly of the crankcase (42). In an embodiment, the engine (40) has a forwardly tilted cylinder head (41). The crankcase (42) extends in a rear direction of the vehicle till a point just before the rear wheel (4). Thus, the crankcase (42) is compact and does not fouls with the rear wheel (4). Preferably, the engine (40) is equipped with an automatic transmission system comprising of an electrically operable gearshift actuation system and an electrically operable clutch actuation system. The AMT engine is compact and the torque from the engine crankshaft is carried to the rear wheel (4) through a chain type transmission. The chain type tranmission includes an engine sprocket member (18) taking its drive from the crankshaft when a clutch provided therein is engaged and a wheel sprocket member (19) supported on the rear wheel (4). The engine sprocket member (18) rotates around a sprocket rotary centre denoted by (P3) and the wheel sprocket member (19) rotates around the rotary centre (P2) of the rear wheel (4). An endless carrying member (15) rotating around the engine sprocket member (18) and the wheeel sprocket member (19), takes the drive from the engine (40) to the rear wheel (4). In an embodiment, the endless carrying member (15) is a chain. In another embodiment, the endless carrying member (15) is a belt. The rear wheel (4) on getting the drive rotates around its rotary centre (P2).
[00020] An air cleaner assembly (61) is operatively connected to the engine (40) for providing clean air to the engine (40) for better combustion/The air cleaner assembly (61) comprises of a pre filter member, a filter element and a post filter member whose detailed construction is known in the art. According to an aspect of the present invention, the air cleaner assembly (61) is positioned between a first conceptual vertical line (LI) passing through the crankshaft centre (PI) of the engine and a second conceptual vertical line (L2) passing through the rotary centre (P2) of the rear wheel (4). Thus, the air cleaner assembly (61) is positioned between the crankshaft centre (PI) of the engine (40) and the rotary « centre (P2) of the rear wheel (4). A third conceptual vertical line (L3) bisecting the air cleaner assembly (61) is behind a fourth conceptual vertical line (L4) passing through a front most point (P4) of the rear wheel (4) such that said air cleaner assembly (61) is disposed substantially behind the front most point (P4) of the rear wheel (4).
[00021] The first conceptual vertical line (LI), the second conceptual vertical line (L2), the third conceptual vertical line (L3), the fourth conceptual vertical line (L4) and the fifth conceptual vertical line (L5) are co-parallel and lie in the same plane. The fourth conceptual vertical line (L4) and the fifth conceptual vertical line (L5).when extends towards the vertical direction pass through the body of the air cleaner assembly (61). As seen is FIG. 4, the first conceptual vertical line (LI) passes through the crankshaft centre (PI) and also through a rotary centre (P2) of the starter motor (43). -

[00022] The air cleaner assembly (61) comprises of a front portion and a rear portion. According to an aspect, the front portion is supported on the crankcase (42) of the engine. Specifically, the front portion is disposed between the first conceptual vertical line (LI) passing through the crankshaft centre (PI) of the engine (40) and a fifth conceptual vertical line (L5) passing through the wheel sprocket rotary centre (P3) of the chain type transmission. FIG. 3 shows the mounting of the front portion in detail. The front portion of the air cleaner assembly (61) comprises of a front boss (62) provided at a lower surface of the air cleaner assembly (61), The front boss (62) is secured to a front mounting bracket (65) secured to the crankcase (42). In an embodiment, the front mounting bracket (65) is a U-shaped bracket secured to the crankcase (42) at least at two points. The front boss (62) is secured to a portion of the U-shaped front mounting bracket (65). In another embodiment, the front mounting bracket (65) is secured to the crankcase (42) at a single point.

[00023] The rear portion of the air cleaner assembly (61) is supported on the swing arm (30). Specifically, the rear portion disposed between the third conceptual vertical line (L3) passing through the front most point (P4) of the rear wheel (4) and the second conceptual vertical line (L2) passing through the rotary centre (P2) of the rear wheel (4). The rear portion is supported on the second supporting tube (32) of the swing arm (30). As shown in FIG. 3, the rear portion comprises of a rear boss (63) provided at a lower surface of the air cleaner assembly (61). The rear boss (63) is secured to a protruding support bracket (35). In an embodiment, the protruding support bracket (35) is formed integral with the second supporting tube (32). In another embodiment, the protruding support bracket (35) is mechanically connected to the second supporting tube (32), preferably by welding.

[00024] FIG. 5 shows the plan view of the naked motorcycle (1). The air cleaner assembly (61) is disposed outward of the rear wheel (4) in the vehicle lateral direction. Thus, the rear wheel (4) has a muffler (71) on one side and the air cleaner assembly (61) on the other side along with the chain type transmission system. The air cleaner assembly (61) is disposed on both sides of the rear pipe (58). As further shown in FIG. 4, a bottom end (66) of the air cleaner assembly (61) is positioned upwards of a front end (41a) of the engine (40). The front end (41a) represents the front most point of the engine (40). Hence, the air cleaner assembly (61) is not positioned at a very higher elevation from the ground. Thus, the centre of gravity of the vehicle is not disturbed owing to this arrangement. Outward mounting of the air cleaner assembly (61) in the lateral direction does not affect the article storing volume in the article storing container.

[00025] The present invention provides an optimal mounting arrangement for the air cleaner assembly (61) in vehicles having compact engines. Precisely, the present invention provides an optimal mounting arrangement for the air cleaner assembly (61) for the scooter type motorcycle (1) having an AMT engine with a chain type transmission. The air cleaner assembly (61) is thus firmly mounted at one end to the compact crankcase (42) and at the other end to the swing arm (30) of the motorcycle (1). The air cleaner assembly (61) does not act as an overhang even though it is extended in the rear direction beyond, the crankcase (42). Since the engine (40) is fixedly supported on the swing arm (30) and the air cleaner assembly (61) is supported on the engine (40) and the swing arm (30), the air cleaner asssembly (61), the engine (40). and the swing arm (30) swing^together which does not disturb the ride comfort of the motorcycle (61).

[00026] The present invention is thus briefly described. It will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the present invention.

We claim;

A scooter type motorcycle (1) comprising:
a vehicle frame assembly comprising a front frame and a rear frame, the rear frame having a swing arm (30) swingably connected to the front frame through a link mechanism and comprising a first supporting tube (31), a second supporting tube (32) angularly disposed to the first supporting tube (31) and a cross tube (33) supporting the second supporting tube (32) on the first supporting tube (31);
an internal combustion engine (40) fixedly supported on the swing arm (30);
a rear wheel (4) disposed behind the engine (40), a chain type transmission mechanism connecting the engine (40) to the rear wheel (4); and
an air cleaner assembly (61) operatively connected to the engine (40);
wherein the air cleaning assembly (61) is positioned between a first conceptual vertical line (LI) passing through a crankshaft centre (PI) of the engine (40) and a second conceptual vertical line (L2) passing through a rotary centre (P2) of the rear wheel (4),
and wherein said air cleaner assembly (61) is disposed substantially behind a front most point (P4) of the rear wheel (4) such that a third conceptual vertical line (L3) bisecting the air .cleaner assembly (61) is behind a. fourth conceptual vertical line (L4) passing through the front most point (P4) of the rear wheel (4).

2. The motorcycle (1) as claimed in claim 1, wherein the air cleaning assembly (61) comprises of a front portion disposed between the first conceptual vertical line (LI) passing through the crankshaft centre (PI) of the engine (40) and a fifth conceptual vertical line (L5) passing through a sprocket centre (P3) of the chain type transmission, and supported on a crankcase (42) of the engine (40).

3. The motorcycle (1) as claimed in claim 2, wherein the front portion of the air cleaning assembly (61) is supported on the crankcase (42) through a U-shaped mounting bracket (65).

4. The motorcycle (1) as-claimed in claim 1, wherein the air cleaning assembly (61) comprises of a rear portion disposed between the third conceptual vertical iine (L3) passing through the front most point (P4) of the rear wheel (4) and the second conceptual vertical line (L2) passing through the rotary centre (P2) of the rear wheel (4) and supported on the second supporting tube (32) of the swing arm (30).

5. The motorcycle (1) as claimed in claim 4, wherein the rear portion of the air cleaning assembly(61) is supported on the second supporting tube (32) through a protruding support bracket (35).

6. The motorcycle (1) as claimed in claim 1, wherein the bottom surface (66) of the air cleaning assembly (61) is positioned upwards of the front end (41a) of the engine (40).

7. The motorcycle (1) as claimed in claim 1, wherein the engine (40) is an automatic transmission engine having automatic gear shift and automatic clutch actuation.

8. The motorcycle (1) as claimed in claiml, wherein the first conceptual vertical line (LI), the second conceptual vertical line (L2), the third conceptual vertical line (L3), the fourth conceptual vertical line (L4) and the fifth conceptual vertical line (L5) are co-parallel and lie in the same plane.

9. The motorcycle (1) as claimed in claiml, wherein an endless carrying member (15) rotating around the engine sprocket member (18) and the wheeel sprocket member(19) takes the drive from the engine (40) to the rear wheel (4).

10. The motorcycle (1) as claimed .in claim 9, wherein, the endless carrying member (15) is a chain or a belt.