EP1429018A2

EP1429018A2 - Arrangement structure of an air cleaner for a scooter type vehicle

Info

Publication number: EP1429018A2
Application number: EP03104493A
Authority: EP
Inventors: Hidehiko Numata; Go Fukuma; Ken Adachi
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2002-12-10
Filing date: 2003-12-02
Publication date: 2004-06-16
Also published as: TWI233463B; CN1318255C; EP1429018A3; MY141841A; CN1506263A; MXPA03011361A; TW200419067A; BR0305285A; JP4133282B2; JP2004189085A

Abstract

The invention relates to an arrangement structure of an air cleaner for a scooter type vehicle wherein an engine 31, a transmission 126, and a drive shaft 63 are integrated with one another is supported for rocking motion on a vehicle body frame 11, crankshaft 62 of the engine is disposed sidewardly of a rear wheel 17, and a carburetor 35 is disposed above the engine while the air cleaner 36 is disposed above the rear wheel disewardly of the carburetor. The air cleaner is connected to the carburetor by a connecting tube 91. With such an arrangement, an air exit of the air cleaner substantially coincides with the carburetor in its heightwise direction, and the air exit is proximate to the carburetor in a forward and backward direction. Therefore, a connecting tube for connecting the air cleaner to the carburetor need not be bent by a great amount, and the length of an intake pipe from the engine to the air cleaner past the carburetor can be increased to increase the capacity of the intake pipe and raise the intake efficiency.

Description

Detailed Description of the Invention

Technical Field to which the Invention Pertains

This invention relates to an arrangement structure of an air cleaner for a scooter type vehicle.

Prior Art

In a conventional arrangement structure of an air cleaner, an engine is provided sidewardly of a rear wheel of a scooter type vehicle, and the air cleaner is disposed above the sidewardly provided engine (refer to, for example, patent document 1).
Meanwhile, in some scooter type vehicle wherein an engine is disposed between the front wheel and the rear wheel, an air cleaner is positioned forwardly of the rear wheel above the engine (refer to, for example, patent document 2).

Patent document 1

Japanese Utility Model Publication No. Hei 1-25119 (page 2, FIG. 3)

Patent document 2

Japanese Patent Publication No. Hei 3-71317 (pages 3-4, FIG. 1)
The patent documents 1 and 2 mentioned above are described in detail below the reference to the drawings.
FIG. 13 is a schematic view of a conventional supporting vehicle body for a motorcycle (copy of FIG. 3 of the patent document 1).
In the conventional supporting vehicle body for a motorcycle, a two-cycle engine is used and an engine/transmission assembly 13 is disposed on the left side of a rear driving wheel 17 while an air cleaner not shown in FIG. 13 is disposed at an upper portion in the inside (within a contour line) of the engine/transmission assembly 13. Further, a silencer 19 is accommodated in a cavity formed forwardly of the rear driving wheel 17.
FIG. 14 is a schematic view of a conventional motorcycle of the scooter type having a two-cycle engine (copy of FIG. 1 of the patent document 2).
In the conventional scooter type motorcycle, a carburetor 32 and an air cleaner 34 are disposed forwardly of a rear wheel 24 above an engine 20, and the air cleaner 34 is connected to the carburetor 32 by a joint 33. Consequently, the intake pipe length is comparatively short.

Problem to be Solved by the Invention

The supporting vehicle body for a motorcycle described above with reference to FIG. 13 is structured such that the air cleaner is provided at an upper portion of the engine/transmission assembly 13 for which a two-cycle engine is used, and where a four-cycle engine is used, it is necessary to secure a predetermined volume for the intake pipe in order to improve the intake efficiency. To this end, a predetermined length is required. For example, where the length of the intake pipe for a four-cycle engine is set to a predetermined length, there is the possibility that the intake pipe may interfere with a cowl 11, and the degree of freedom when a length of the intake pipe is to be set cannot be raised readily.
The scooter type motorcycle described above with reference to FIG. 14 uses the joint 33 for the connection between the carburetor 32 and the air cleaner 34. However, since the joint 33 has a channel-shape and is bent in an L-shape, the intake air resistance of the joint 33 is high.
Further, the intake pipe is connected to the front side of the air cleaner 34. Therefore, it is cumbersome, because the front side of the air cleaner 34 cannot be removed upon maintenance of the air cleaner 34.
Therefore, it is an object of the present invention to provide an arrangement structure of an air cleaner for a scooter type vehicle wherein a connecting tube for connecting the air cleaner to a carburetor can be set to a desired curve and length to achieve reduction of the intake air resistance and raise the intake efficiency of an intake system. Further, the air cleaner is accommodated compactly in a vehicle body cover and is easy in maintenance.

Means for Solving the Problem

In order to attain the object described above, according to claim 1, an arrangement structure of an air cleaner for a scooter type vehicle wherein a power unit including an engine, a transmission, and a support shaft for a rear wheel integrated with one another is disposed at a rear portion of a vehicle body below a seat and supported for rocking motion on a vehicle body frame is characterized in that a crankshaft of the engine is disposed sidewardly of the rear wheel while a carburetor is disposed above the engine, and the air cleaner is disposed sidewardly of the carburetor above the rear wheel.
An air exit of the air cleaner substantially coincides with the carburetor in its heightwise direction, and the air exit is proximate to the carburetor in a forward and backward direction. Therefore, a connecting tube for connecting the air cleaner to the carburetor need not be bent by a great amount, and the length of an intake pipe from the engine to the air cleaner past the carburetor can be increased to increase the capacity of the intake pipe and raise the intake efficiency.
According to claim 2, the arrangement structure of an air cleaner for a scooter type vehicle is characterized in that the air cleaner includes a front side case and a rear side case divided in forward and backward directions of the vehicle, and the rear side case is secured to the engine side while the carburetor is connected to the rear side case by a connecting tube.
Since the air cleaner includes the front side case and the rear side case and the carburetor is connected to the rear side case by the connecting tube, the rear side case is secured to the engine side, and by opening a vehicle body cover and removing the front side case of the air cleaner, maintenance of an element can be performed readily.
According to claim 3, the arrangement structure of an air cleaner for a scooter type vehicle is characterized in that a vehicle body cover, which covers the upper side of the engine below the seat, is supported for pivotal motion in upward and downward directions around a hinge provided on a rear side of the vehicle body.
Even where the arrangement structure of an air cleaner of the present invention, a space can be assured around the air cleaner and no much time is required for inspection of the air cleaner.
According to claim 4, the arrangement structure of an air cleaner for a scooter type vehicle is characterized in that the vehicle body frame is a pipe frame.
Since the vehicle body frame is not a monocock frame integrated with a cover, maintenance of the air cleaner and so forth can be performed readily by removing the cover.

Brief Description of the Drawings

FIG. 1 is a left side elevational view of a scooter type vehicle according to the present invention.
FIG. 2 is a left side elevational view of a power unit, which adopts an arrangement structure of an air cleaner according to the present invention.
FIG. 3 is a plan view of the power unit, which adopts the arrangement structure of an air cleaner according to the present invention.
FIG. 4 is an exploded view of the air cleaner according to the present invention.
FIG. 5 is a view as viewed in the direction indicated by an arrow mark 5 in FIG. 4.
FIG. 6 is a sectional view taken along line 6-6 of FIG. 2.
FIG. 7 is a sectional view taken along line 7-7 of FIG. 2.
[FIG. 8]
FIG. 8 is a left side elevational view of a body cover unit according to the present invention.
FIG. 9 is an exploded view of a hinge according to the present invention.
[FIG. 10]
FIG. 10 is a perspective view of a rear grip according to the present invention.
FIG. 11 is a sectional view taken along line 11-11 of FIG. 1.
FIG. 12 is a view illustrating opening/closing of a vehicle body cover, which covers the arrangement structure of an air cleaner according to the present invention.
FIG. 13 is a schematic view showing a conventional supporting vehicle body for a motorcycle.
FIG. 14 is a schematic view of a conventional scooter type motorcycle, which includes a two-cycle engine.

Mode for Carrying out the Invention

An embodiment of the present invention is described below with reference to the accompanying drawings. It is to be noted that the drawings should be viewed in the direction of reference characters. The "left" and the "right" are directions as viewed from a driver, and the "front" is the advancing side while the "rear" is the opposite side.
FIG. 1 is a left side elevational view of a scooter type vehicle according to the present invention. The scooter type vehicle 10 is a scooter, which includes, as principal components thereof, a vehicle body frame 11, a front fork 12 attached to a front portion of the vehicle body frame 11, and a front wheel 13, a front fender 14, and a handle bar 15 attached to the front fork 12. The scooter type vehicle 10 further includes, as principal components thereof, a power unit 16 of the swing type attached to a lower portion of the vehicle body frame 11, a rear wheel 17 attached to a rear portion of the power unit 16, and a rear suspension 21 on which the power unit 16 is suspended. The scooter type vehicle 10 further includes, as principal components thereof, a luggage box 22 disposed at a middle portion of the vehicle body frame 11, a seat 23 disposed above the luggage box 22, a fuel tank 24 attached to an upper portion of the vehicle body frame 11, a body cover 25 for covering the vehicle body frame 11, and a rear grip 26 provided at a rear portion of the vehicle body frame 11. Reference numeral 27 denotes a hinge attached to a rear portion of the vehicle body frame 11, and 28 a body cover unit. Although the body cover 25 is formed from an iron plate, it may otherwise be formed from a resin.
The power unit 16 includes a four-cycle engine 31 and a transmission mechanism 32. The engine 31 includes an exhaust system 33, and a carburetor 35 and an air cleaner 36 of an intake system 34.
The exhaust system 33 includes an exhaust pipe 37 and a silencer 38. The exhaust pipe 37 is attached to the engine 31, and a silencer 38 is connected integrally to the exhaust pipe 37. The silencer 38 is secured by a muffler stay 39.
FIG. 2 is a left side elevational view of the power unit, which adopts an arrangement structure of an air cleaner according to the present invention. FIG. 2 shows the engine 31, transmission mechanism 32, exhaust system 33 (muffler stay 39), carburetor 35, and air cleaner 36 of the power unit 16. FIG. 2 further shows that the carburetor 35 is disposed above the engine 31 and the air cleaner 36 is disposed above the rear wheel 17.
The muffler stay 39 is welded at a base portion thereof to the muffler and has upper and lower attaching portions 41 and 42 formed thereon for being attached to the power unit 16. A silencer attaching portion 43 and an air cleaner attaching portion 44 are formed at the upper attaching portion 41.
The air cleaner 36 includes a front side case 46 formed by division in the forward and rearward direction of the scooter type vehicle 10, a rear side case 47 secured to the engine side, and a filter element 48 provided between the front and rear side cases 46 and 47. Reference numeral 51 denotes an air entrance formed in the front side case 46.
The rear side case 47 has a case body 53 formed thereon for introducing air only by a predetermined volume. A first securing portion 54 is formed at a lower portion of the case body 53, and a rear fender 55 is provided such that it extends downwardly from a lower portion of the rear side case 47 and covers the front side of the rear wheel 17. A second securing portion 56 is formed at a lower portion of the rear fender 55. Further, a third securing portion 57 is formed at a lower portion of an edge of the case body 53, and an air exit 58 is perforated at a side portion of the case body 53.
FIG. 2 further shows the vehicle body frame 11, a suspension link 61 and the rear suspension 21, which support the power unit 16 for rocking motion on the vehicle body frame 11, a crankshaft 62 of the engine 31. The crankshaft 62 is disposed sidewardly of the rear wheel 17. Reference numeral 63 denotes a drive shaft as a rear wheel supporting shaft.
A supporting arm 65 for being supported on the suspension link 61 is formed on a crankcase 64 of the power unit 16, and first and second seat portions 66 and 67 for securing the air cleaner 36 are formed on the crankcase 64 of the power unit 16. Further, a third seat portion 68 for securing the muffler stay 39 is formed on the crankcase 64 of the power unit 16.
The vehicle body frame 11 is a pipe frame, which has a rear frame 72 joined to a centrally located down pipe 71.
The rear frame 72 is configured such that a lower cross member 74 is attached to lower portions of left and right left and right rear pipes 73, 73 (refer to FIG. 3) and a link connection member 75 (a pipe 76 and lugs 77, 77 [refer to FIG. 3]) is secured by welding to a rear end of the down pipe 71 while an upper first cross member 81 and an upper second cross member 82 are attached to an upper portion of the rear frame 72. A pair of support pipes 83 (refer also to FIG. 3) are provided between the pipe 76 and the lower cross member 74.
The rear frame 72 further includes brackets 84, 84 (refer to FIG. 11) attached to the upper first cross member 81 and a bracket 85 for the rear suspension 21 attached to the upper second cross member 82.
FIG. 3 is a plan view of the power unit, which adopts the arrangement structure of an air cleaner according the present embodiment. FIG. 3 shows the engine 31, transmission mechanism 32, exhaust system 33 (muffler stay 39), and intake system 34 (carburetor 35 and air cleaner 36) of the power unit 16 described hereinabove. FIG. 3 further shows that the air cleaner 36 is disposed sidewardly of the carburetor 35 and the crankshaft 62 of the engine 31 is disposed sidewardly of the rear wheel 17.
The intake system 34 is structured such that an L-shaped connecting tube 91 is connected to the air exit 58 of the rear side case 47 of the air cleaner 36 and the carburetor 35 is connected to the connecting tube 91 while an intake manifold 92 is connected to the carburetor 35 and further connected to the engine 31. External air is taken in as indicated by an arrow mark 1 ○ through the air entrance 51 of the front side case 46 of the air cleaner 36 and is filtered by the filter element 48. The clean air after the filtration is taken in through the air exit 58 and introduced as indicated by an arrow mark 2 ○ by the L-shaped connecting tube 91.
The air cleaner 36 is secured such that the first securing portion 54 of the rear side case 47 disposed above the rear wheel 17 is attached to the first seat portion 66 of the crankcase 64, the second securing portion 56 of the rear fender 55 is attached to the second seat portion 67 of the crankcase 64, and the third securing portion 57 is attached to the air cleaner attaching portion 44 of the muffler stay 39. Reference character 93, ... (... indicates a plural number. This similarly applies to the following description) denote fastening screws for fastening the front side case 46 to the rear side case 47.
FIG. 4 is an exploded view of the air cleaner according to the present invention. FIG. 4 shows the front side case 46, the rear side case 47, the filter element 48 provided between the front and rear side cases 46 and 47, and the fastening screws 93, .... As described hereinabove, the first securing portion 54 is formed at a portion of the rear side case 47 below the case body 53 and the rear fender 55 is provided such that it extends downwardly from a lower portion of the rear side case 47 and covers the rear wheel. Further, the second securing portion 56 is formed at a lower portion of the rear fender 55, and the third securing portion 57 is formed at a lower portion of an edge of the case body 53.
FIG. 5 is a view as viewed in a direction indicated by an arrow mark 5 in FIG. 4. FIG. 5 shows the first securing portion 54 of the rear side case 47, the rear fender 55, the second securing portion 56 formed at a lower portion of the rear fender 55, and the third securing portion 57 formed at a lower portion of an edge of the case body 53.
FIG. 6 is a sectional view taken along line 6-6 of FIG. 2 and shows a cross section of the suspension link 61 and the link connection member 75 (pipe 76 and lugs 77, 77).
The suspension link 61 includes an arm 105 secured to a buffer member 95 (an inner pipe 101, a first rubber member 102, a fitting pipe 103, and a second stopper rubber member 104). The suspension link 61 is attached in the following manner. First, the arm 105 of the suspension link 61 is connected to the supporting arm 65 of the crankcase 64 of the power unit 16 by means of a first bold 106, and then the buffer member 95 of the suspension link 61 is connected to the lugs 77, 77 of the link connection member 75 of the vehicle body frame 11 by means of a second bold 107. Then, the second stopper rubber member 104 is fitted simultaneously with the fitting pipe 103 into the down pipe 71.
It is to be noted that the power unit 16 may be assembled to the power unit 16 through the suspension link 61 in an arbitrary procedure.
The muffler stay 39 is secured to the power unit 16 in the following manner. The lower attaching portion 42 of the muffler stay 39 is attached to the third seat portion 68 positioned on the supporting arm 65 of the crankcase 64 by means of a bolt 111. Meanwhile, also the upper attaching portion 41 (refer to FIG. 2) of the muffler stay 39 is attached similarly by means of a bolt 111 (refer to FIG. 3).
FIG. 7 is a sectional view taken along line 7-7 of FIG. 2. FIG. 7 shows a cross section of the engine 31 of the power unit 16 and the transmission mechanism 32 in an exploded state and shows principal configurations of them.
The engine 31 is a four-cycle engine and includes a cylinder block 114, a cylinder head 115, a camshaft 116, a cam chain 117, a piston 118, the crankshaft 62, an AC generator (ACG) 121, a primary drive gear 122, and the crankcase 64.
The transmission mechanism 32 includes a clutch 125, a transmission 126, and the rear wheel 17.
The clutch 125 includes a primary driven gear 127, which meshes with the primary drive gear 122, a clutch disk 131, and a spring 132.
The cam chain 117 and the clutch 125 are disposed on the inner side of the vehicle body and prevented from projecting to the outside of the vehicle body.
The transmission 126 is a four-speed return type transmission and includes a main shaft 135 on which the clutch 125 is fitted, a drive gear 136 (driving side gear) fitted on the main shaft 135, a driven gear (receiving side gear) 137 fitted on the drive shaft 63, and a shift mechanism 139 for securing a desired gear (for example, a low gear 138) selected from the driven gear 137 to the drive shaft 63.
Now, the body cover unit, which covers the upper side of the engine 31, is described.
FIG. 8 is a left side elevational view of the body cover unit according to the present invention. The body cover unit 28 is formed from the luggage box 22, the seat 23, a rear cover 141, the rear grip 26, and a hinge first bracket 142 of the hinge 27 integrally assembled thereto. The body cover unit 28 covers the upper side of the engine 31 (refer to FIG. 1) below the seat 23. Reference character 22a denotes a bolt for securing a front lower portion of the luggage box 22.
FIG. 9 is an exploded view of the hinge according to the present invention. The hinge 27 includes a hinge second bracket 143 and a pivot pipe 144. The hinge second bracket 143 is assembled to the upper second cross member 82 at the rear ends of the left and right rear pipes 73, 73, and the pivot pipe 144 is attached to the hinge second bracket 143. The hinge 27 further includes cushion rubber members 145, 145 and U-Shaped guide members 146, 146. The cushion rubber members 145, 145, is attached to the opposite ends of the pivot pipe 144 as indicated by an arrow mark 3 ○, and the U-shaped guide members 146, 146 of the hinge first bracket 142 are fitted on the cushion rubber members 145, 145 as indicated by an arrow mark 4 ○. Reference numerals 147, 147 denote holes through which bolts for attaching the rear grip 26 (refer to FIG. 8) are passed.
FIG. 10 is a perspective view of the rear grip according to the present invention. The rear grip 26 servers also as a reinforcement member for the body cover unit 28 (refer to FIG. 8). The rear grip 26 is structured such that rear ends 152, 152 of a sub frame 151 for supporting the luggage box 22 (refer to FIG. 8) are attached to a U-shaped first grip 148, and second grips 153, 153 are secured to the sub frame 151. Further, lugs 155, 155 are attached to front ends 154, 154 of the sub frame 151. Lower ends 148a, 148a of the first grip 148 are fitted into recessed portions having holes 147(refer to FIG. 9), 147 (refer to FIG. 9) for passing bolts therethrough, and then bolts are screwed into them to secure the rear grip 26 to the hinge first bracket 142.
Now, an outline of attachment of the rear grip 26 is described.
First, the hinge first bracket 142 (refer to FIG. 9) is fastened to the lower ends 148a, 148a of the U-shaped first grip 148 by means of bolts, and a rear portion of the luggage box 22 and an upper end portion of the rear cover 141 are secured to the lugs 155, 155 provided at front ends of the sub frame 151 by means of stud bolts 157, 157 to form the body cover unit 28 (refer to FIG. 8) integrated with the rear grip 26 side. Then, the rear grip 26 is attached to the rear frame 72 (refer to FIG. 9) of the vehicle body frame. In particular, the hinge first bracket 142 (fitted as indicated by an arrow mark 4 ○ in FIG. 9) is assembled, and the lugs 155, 155 of the rear grip 26 are secured to the brackets 84 (refer to FIG. 2) of the upper first cross member 81 (refer to FIG. 2) of the vehicle body frame by means of opening/closing volts 158, 158. This is described particularly with reference to a next figure.
FIG. 11 is a sectional view taken along line 11-11 of FIG. 1 and shows a configuration for attachment and removal of a central portion of the body cover unit 28.
As described hereinabove, a central portion of the body cover unit 28 has an attachment configuration wherein the luggage box 22 and the rear cover 141 are combined integrally by means of the stud bolts 157, 157 welded to the lugs 155, 155 of the rear grip 26, and the three parts are secured to the brackets 84, 84 of the upper first cross member 81 of the vehicle body frame 11 by means of the opening/closing volts 158, 158. On the other hand, upon removal, the opening/closing volts 158, 158 and the bolt 22a (refer to FIG. 8) at a front lower portion of the luggage box 22 are removed (with the seat 23 opened). Consequently, the parts can be pivoted in an integrated state, that is, in the form of the body cover unit 28.
FIG. 12 is a view illustrating opening/closing of the vehicle body cover, which covers the arrangement structure of an air cleaner according to the present invention. The body cover unit 28 covers the upper side of the engine 31 below the seat 23 and is pivoted upwardly and downwardly (in the directions indicated by arrow marks 5 ○ and 6 ○) around the hinge 27 provided on the rear side of the vehicle body frame 11.
Now, an outline of opening and closing of the body cover unit 28 is described briefly.
First, the seat 23 is opened, and the bolt 22a (refer to FIG. 8) for securing the bottom of the luggage box 22 to the vehicle body frame 11 and the opening/closing volts 158, 158 for securing a central portion of the body cover unit 28 are removed, whereafter the seat 23 is closed. Then, the rear cover 141 is opened as indicated by an arrow mark 5 ○. In other words, the body cover unit 28 is pivoted upwardly (in the direction indicated by the arrow mark 5 ○).
Operation of the arrangement structure of an air cleaner for a scooter type vehicle described above is described below.
The crankshaft 62 of the engine 31 is disposed sidewardly of the rear wheel 17 and the carburetor 35 is disposed above the engine 31 while the air cleaner 36 is disposed above the rear wheel 17 sidewardly of the carburetor 35. Therefore, when the power unit 16 wherein the engine 31, transmission 126, and drive shaft (rear wheel supporting shaft) 63 are integrated with one another as shown in FIGS. 2 and 3 are attached, the center 162 of the air exit 58 of the air cleaner 36 substantially coincides with the center axial line 161 of the carburetor 35 in its heightwise direction (direction indicated by an arrow mark 7 ○). Further, the intake pipe extends from the engine 31 to the air cleaner 36 past the carburetor 35 without being bent, and consequently, the length of the intake pipe can be increased to expand the volume of the intake pipe thereby to improve the intake efficiency.
Further, where the connecting tube 91 is formed in an L-shape, the intake air resistance can be suppressed.
Further, since the air cleaner 36 includes the front side case 46 and the rear side case 47 and the carburetor 35 is connected to the rear side case 47 by the L-shaped connecting tube 91, the connecting tube 91 is simplified in shape and can be accommodated compactly in the body cover unit (vehicle body cover) 28.
As shown in FIG. 12, the body cover unit 28, which covers the upper side of the engine 31 below the seat 23, is pivoted upwardly and downwardly around the hinge 27 provided on the rear side of the vehicle body, more particularly, on the rear side of the vehicle body frame 11. Therefore, even where the arrangement structure (refer to FIGS. 1 and 2) of the air cleaner 36 is adopted, a space can be assured around the air cleaner 36, and no much time is required for inspection of the air cleaner 36 (refer to FIG. 4).
Further, since the body cover unit 28, which covers the upper side of the engine 31 below the seat 23, is pivoted upwardly and downwardly around the hinge 27 provided on the rear side of the vehicle body frame 11, even where the crankshaft 62 of the engine 31 is disposed sidewardly of the rear wheel 17 and the carburetor 35 is disposed above the engine 31, a great space can be assured around the engine 31.
With regard to the air cleaner 36, the first securing portion 54 is formed at a lower portion of the case body 53 of the rear side case 47, and the rear fender 55 is provided such that it extends downwardly from a lower portion of the case body 53 and covers the rear wheel. Further, the second securing portion 56 is formed at a lower portion of the rear fender 55, and the third securing portion 57 is formed at a rear portion of an edge of the case body 53. Consequently, the air cleaner 36 can be arranged at a predetermined position above the rear wheel 17.
It is to be noted that the shapes of the front and rear side cases 46 and 47 of the air cleaner 36 illustrated in the embodiment of the present invention are a mere example, and, for example, depending upon the specifications of the engine, the capacity of the air cleaner or the position of the crankcase 64 at which the air cleaner is secured may be changed. Also the position of the air entrance 51 can be changed.

Effects of the Invention

The present invention exhibits the following effects due to the configuration described above.
According to claim 1, an arrangement structure of an air cleaner for a scooter type vehicle wherein a power unit including an engine, a transmission, and a support shaft for a rear wheel integrated with one another is supported for rocking motion on a vehicle body frame is configured such that a crankshaft of the engine is disposed sidewardly of the rear wheel while a carburetor is disposed above the engine, and the air cleaner is disposed sidewardly of the carburetor above the rear wheel. Therefore, an air exit of the air cleaner substantially coincides with the carburetor in its heightwise direction, and the air exit is proximate to the carburetor in a forward and backward direction. Therefore, a connecting tube for connecting the air cleaner to the carburetor need not be bent by a great amount, and the length of an intake pipe from the engine to the air cleaner past the carburetor can be increased to increase the capacity of the intake pipe and raise the intake efficiency.
Further, where the connecting tube is formed in an L-shaped bent configuration and is set to a desired length, the intake air resistance can be suppressed to a desired value.
According to claim 2, the air cleaner includes a front side case and a rear side case divided in forward and backward directions of the vehicle, and the rear side case is secured to the engine side while the carburetor is connected to the rear side case by a connecting tube. Therefore, the rear side case is secured to the engine side, and by opening a vehicle body cover and removing the front side case of the air cleaner, maintenance of an element can be performed readily.
According to claim 3, a vehicle body cover, which covers the upper side of the engine below the seat, is supported for pivotal motion in upward and downward directions around a hinge provided on a rear side of the vehicle body. Therefore, even where the arrangement structure of an air cleaner of the present invention, a space can be assured around the air cleaner and no much time is required for inspection of the air cleaner.
Further, since the vehicle body cover, which covers the upper side of the engine below the seat, is pivoted upwardly and downwardly around the hinge provided on the rear side of the vehicle body, even where the crankshaft of the engine is disposed sidewardly of the rear wheel and the carburetor is disposed above the engine, a great space can be assured around the engine.
According to claim 4, the vehicle body frame is a pipe frame. Therefore, since the vehicle body frame is not a monocock frame integrated with a cover, maintenance of the air cleaner and so forth can be performed readily by removing the cover.

Claims

An arrangement structure of an air cleaner for a scooter type vehicle wherein a power unit including an engine, a transmission, and a support shaft for a rear wheel integrated with one another is disposed at a rear portion of a vehicle body below a seat and supported for rocking motion on a vehicle body frame, characterized in that
a crankshaft of said engine is disposed sidewardly of said rear wheel while a carburetor is disposed above said engine, and said air cleaner is disposed sidewardly of said carburetor above said rear wheel.
An arrangement structure of an air cleaner for a scooter type vehicle according to claim 1, characterized in that said air cleaner includes a front side case and a rear side case divided in forward and backward directions of said vehicle, and said rear side case is secured to said engine side while said carburetor is connected to said rear side case by a connecting tube.
An arrangement structure of an air cleaner for a scooter type vehicle according to claim 1, characterized in that a vehicle body cover, which covers the upper side of said engine below said seat, is supported for pivotal motion in upward and downward directions around a hinge provided on a rear side of said vehicle body.
An arrangement structure of an air cleaner for a scooter type vehicle according to claim 1, characterized in that said vehicle body frame is a pipe frame.