JP4015218B2 - Scooter type motorcycle - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a scooter type motorcycle including a unit swing type engine and an air intake system for introducing secondary air into an exhaust system of the engine.
[0002]
[Prior art]
In general, a scooter type motorcycle is equipped with a unit swing type engine. This unit swing type engine unites an engine as a drive source with a transmission case incorporating a V-belt type automatic transmission and a power transmission mechanism. It is comprised as.
[0003]
By the way, in a motorcycle that uses a two-cycle engine as a drive source, unburned components such as oil are contained in the exhaust gas discharged from the two-cycle engine, so fresh air is introduced into the exhaust pipe by an air intake system. Then, the exhaust gas may be purified by burning unburned components in the exhaust gas flowing through the exhaust pipe.
[0004]
[Problems to be solved by the invention]
However, when an air intake system is incorporated into a small scooter type motorcycle, the arrangement becomes a problem, and a compact and rational arrangement of the air intake system is desired.
[0005]
The present invention has been made in view of the above circumstances, and the object of the present invention is a scooter type motorcycle that can realize a compact and rational arrangement of the air intake system and keep the height of its components low. Is to provide.
[0006]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention arranges a unit swing type engine configured by integrating an engine and a transmission case including an automatic transmission and a power transmission mechanism below the seat, In a scooter type motorcycle equipped with an air intake system for introducing fresh air into an exhaust system, a valve unit that constitutes the air intake system and includes a check valve having a valve body is provided in the unit swing type engine. The valve unit is arranged in such a direction that the valve body opens and closes in the vertical direction. The valve unit includes a suction duct that allows the fresh air to flow into the valve unit, and a discharge duct that is provided above the suction duct. And the valve body is provided between the suction duct and the discharge duct and moves upward to check the check. Open, characterized by closing the check valve to move downward.
[0007]
Therefore, according to the present invention, since the check valve built in the valve unit constituting the air intake system is arranged in the direction in which the valve body opens and closes in the vertical direction, the height of the valve unit can be kept low, Accordingly, the compact valve unit having a low height can be rationally arranged on the transmission case of the unit swing type engine while avoiding interference with other parts.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0009]
First, the overall configuration of the scooter type motorcycle according to the present invention will be described with reference to FIG. FIG. 1 is an overall side view of a scooter type motorcycle according to the present invention.
[0010]
The scooter type motorcycle 1 according to the present embodiment is for off-road use, and a head pipe 2 is located at the front upper part of the vehicle body, and a steering shaft 3 is rotatably inserted into the head pipe 2. is doing. A steering wheel 4 is attached to the upper end of the steering shaft 3, and a front fork 5 is attached to the lower end of the steering shaft 3. A front wheel 6 is rotatable at the lower end of the front fork 5. It is pivotally supported.
[0011]
Further, after the down tube 7 extends obliquely downward toward the rear of the vehicle body from the head pipe 2, it is bent and extends substantially horizontally toward the rear of the vehicle body. A pair of seat rail frames 8 diverge and extend obliquely upward toward the rear of the vehicle body.
[0012]
By the way, the head pipe 2, the down tube 7 and the like at the front of the vehicle body are covered with a resin front cover 9, and a low floor type footrest 11 is provided between the handle 4 and the seat 10. Yes.
[0013]
On the other hand, a unit swing type engine 12 as a power unit is provided below the seat 10. The unit swing type engine 12 is configured by integrating a two-cycle engine 13 as a drive source and a transmission case 14 having a built-in V belt type automatic transmission and a power transmission mechanism (not shown). A rear wheel 15 is rotatably supported at one rear end of the engine 13 extending from one side (left side of the vehicle body) to the rear of the vehicle body. The exhaust pipe 16 led out from the exhaust system of the engine 13 extends on the right side of the vehicle body (the back side in FIG. 1) toward the rear of the vehicle body, and a muffler 17 disposed on the right side of the rear wheel 15 is connected to the rear end. Yes.
[0014]
Thus, the unit swing type engine 12 is swingably supported by an engine suspension bracket 18 fixed to an intermediate portion of the seat rail frame 8, and the rear end upper portion thereof is supported by the seat rail frame 8 via the rear cushion 19. It is supported by.
[0015]
On the other hand, a portion of the vehicle body below the seat 10 is covered with a resin vehicle body cover 20, and a storage box 21 and a fuel tank 22 having an upper surface opened are stored in the vehicle body cover 20 in the front and rear directions. These oil tanks 23 are arranged on the sides.
[0016]
By the way, the handle 4 is covered with a resin handle cover 24, and the grips 25 provided at both left and right ends of the handle 4 are covered with resin grip guards 26 at the front.
[0017]
Here, the configuration of the fresh air introduction system of the unit swing type engine 12 will be described with reference to FIGS. 2 is a partial side view of the lower part of the footrest showing the configuration of the fresh air introduction system of the unit swing type engine, and FIG. 3 is a partial plan view of the lower part of the footrest.
[0018]
The footrest 11 is integrally formed of resin, and its left and right ends are bent downward. As shown in FIG. 2, the footrest 11 is mounted and mounted on front and rear cross members 27 and 28 laid between the pair of left and right seat rail frames 8. Both sides are covered with an under cover 29 that is also integrally formed of resin. Therefore, a space surrounded by the footrest 11 and the under cover 29 is formed below the footrest 11.
[0019]
Thus, the space formed below the footrest 11 is partitioned by the front and rear panels 30 and 31 that are supported suspended from the front and rear of the footrest 11. A clean room S defined by the mounting table 11, the under cover 29, and the front and rear panels 30 and 31 is formed. The panels 30 and 31 are formed into a thin plate shape by flexible soft vinyl chloride or rubber. At the same time as the under cover 29 is attached, the foot mount 11 and the under cover 29 and A clean room S defined by the front and rear panels 30 and 31 is formed. In this case, since the peripheral edges of the flexible panels 30 and 31 are in close contact with the inner wall of the under cover 29, the gap is filled. Intrusion of mud etc. into the water is reliably prevented.
[0020]
On the other hand, as shown in FIGS. 2 and 3, an intake duct 37 is provided from an intake port 36 a of an air cleaner 36 provided at the front of the unit swing type engine 12 disposed on the left side of the vehicle body behind the footrest 11. This intake duct 37 is extended forward of the vehicle body, and its front end is drawn into the clean chamber S defined below the footrest 11 to open into the clean chamber S. It has been.
[0021]
The intake duct 37 includes a bellows-like flexible pipe 37a whose one end is connected to an intake port 36a of an air cleaner 36 by a clamp 38, and an intake pipe 37b connected to a tip portion of the flexible pipe 37a by a clamp 39. The intake pipe 37b is attached to and supported by the left seat rail frame 8 via the bracket 40.
[0022]
Incidentally, in the present embodiment, the interior of the air cleaner 36 is partitioned into two chambers S1 and S2 as shown in FIG. 2, and the intake port 36a is opened in one chamber S1, and the chamber S1 communicates with the inside of the transmission case 14 via a fresh air introduction duct 14a of the transmission case 14 connected to the discharge port 36b that opens rearwardly at the lower portion of the air cleaner 36. Further, another air inlet 36c is opened in the other chamber S2 of the air cleaner 36, and the chamber S2 is connected to a carburetor 46 (see FIG. 3) via an air intake pipe 45 connected to the upper surface of the air cleaner 36. ing.
[0023]
Next, the transmission case 14 of the unit swing type engine 12 and its internal configuration will be described with reference to FIGS. 4 is a partial plan sectional view of the unit swing type engine showing the configuration inside the transmission case, FIG. 5 is a side view of the transmission case, and FIG. 6 is an enlarged sectional view taken along line AA in FIG.
[0024]
As shown in FIG. 4, a crankshaft 71, a driven shaft 72, an intermediate shaft (not shown) and an output shaft (rear axle) 73 of the engine 13 are parallel to each other in the transmission case 14 from the front (left side in FIG. 4). It is arranged.
[0025]
Thus, the rotation of the crankshaft 71 is automatically shifted by the V-belt type automatic transmission 80 and transmitted to the driven shaft 72. The rotation of the driven shaft 72 includes the gear 72a formed on the driven shaft 72 and the intermediate shaft 72a. The rear wheel 15 is transmitted to the output shaft 73 through a power transmission mechanism including a gear (not shown) supported by the shaft and a gear 74 coupled to the output shaft 73, and the rear wheel 15 supported by the output shaft 73 is Driven by rotation.
[0026]
The V-belt type automatic transmission 80 has an endless V between a drive pulley 75 provided at one end portion of the crankshaft 71 and a driven pulley 76 provided at one end portion (overhang portion) of the driven shaft 72. The belt 77 is wound around.
[0027]
Incidentally, a fixed sheave 75a and a cam plate 78 are fixed at a predetermined distance to the end of the crankshaft 71, and a movable sheave 75b is slidably fitted on the crankshaft 71 therebetween. The drive pulley 75 includes a fixed sheave 75a and a movable sheave 75b. A plurality of centrifugal weights 79 are accommodated in a space formed between the movable sheave 75b and the back side of the cam plate 78 so as to be movable in the radial direction.
[0028]
Thus, a plurality of fins 81 are integrally formed on the outer periphery of the back surface of the fixed sheave 75a, and the fixed sheave 75a constitutes a centrifugal cooling fan.
[0029]
On the other hand, a hollow shaft 82 is rotatably supported on the outer periphery of the overhang portion of the driven shaft 72, and a fixed sheave 76 a is attached to the inner end portion of the hollow shaft 82. A movable sleeve 83 is fitted on the outer periphery of the hollow shaft 82 so as to be slidable in the axial direction, and the driven sheave 76b connected to the inner end of the movable sleeve 83 and the driven sheave 76a. A pulley 76 is configured.
[0030]
A centrifugal clutch 84 is provided at the end of the driven shaft 72, and a spring 86 is mounted between the clutch inner 85 of the centrifugal clutch 84 and the movable sheave 76 b of the driven pulley 76. The movable sheave 76b and the movable sleeve 83 are constantly urged toward the fixed sheave 76a by a spring 86.
[0031]
By the way, in the present embodiment, the transmission case 14 is constituted by a traditional case body integrated with the crankcase of the engine 13 and a case cover 14A covering the side portion of the main body, and a front end portion of the case cover 14A. A portion (a crescent-shaped portion hatched in FIG. 5) has a concave portion a (FIG. 4) close to the fixed sheave 75a of the drive pulley 75 (more specifically, the fin 81 constituting the cooling fan of the fixed sheave 75a). And FIG. 6). As shown in FIG. 5, a fresh air introduction duct 14a inclined downward toward the front of the vehicle body is integrally formed in the recess a of the case cover 14A. The fresh air introduction duct 14a is formed on the case cover 14A. Opening into the recess a.
[0032]
As shown in FIG. 4, a fresh air outlet 14b is opened at the rear of the case cover 14A. As shown in FIGS. 5 and 6, a circular opening 14c is formed at the upper front end of the case cover 14A. Is formed. As shown in FIG. 6, the opening 14c has a wall portion 14c-1 that is finned so that the fresh air flowing through the opening 14c is not affected by the wind induced by the cooling fan constituted by the fixed sheave 75a. 81 (see FIG. 4).
[0033]
Thus, the scooter type motorcycle 1 according to the present embodiment is provided with an air intake system (hereinafter referred to as AIS), and fresh air is introduced into the exhaust pipe 16 by this AIS. Thus, unburned components in the exhaust gas flowing through the exhaust pipe 16 are combusted, thereby purifying the exhaust gas.
[0034]
Here, the configuration and arrangement of the AIS will be described with reference to FIGS. 7 is a partially broken plan view of a unit swing type engine showing the configuration and arrangement of the AIS, FIG. 8 is a view in the direction of arrow B in FIG. 7, and FIG. 9 is a broken side view of the valve unit.
[0035]
As shown in FIGS. 7 and 8, a valve unit 50 is installed on the transmission case 14 of the unit swing type energin 12. As shown in FIG. 9, the valve unit 50 is configured by incorporating a filter element 52 and a valve 53 in a valve case 51 configured by joining an upper case 51A and a lower case 51B. Thus, the valve case 51 is covered with the case cap 55 via the damper 54.
[0036]
By the way, as shown in FIG. 9, a suction duct 51a that opens toward the front of the vehicle body is integrally provided on the left side of the front end of the lower case 51B of the valve unit 50, and a flange is provided at the rear end of the lower case 51B. 51b is integrally projected, and a circular hole 51c is formed in the flange 51b. Two columnar columns 51d are erected in the lower case 51B. Further, a discharge duct 51e that opens obliquely rightward toward the front of the vehicle body is integrally provided at the front end of the upper case 51A.
[0037]
Thus, the filter element 52 is supported in the valve case 51 by the plate 56 sandwiched between the upper case 51A and the lower case 51B, and the upper case S3 and the lower chamber S3 are supported by the filter element 52 in the valve case 51. It is partitioned into a room S4.
[0038]
As described above, the valve 53 is provided in the valve case 51, and two cylindrical bosses 57a project from the lower surface of the base plate 57 of the valve 53, and these bosses 57a are connected to the lower case. The base plate 57 is supported substantially horizontally in the valve case 51 as shown in the figure by fitting the column 51d upright on the column 51B from above. A thin plate-like reed valve 58 as a check valve for opening and closing an opening 57b formed in the base plate 57 is attached to the upper surface of the base plate 57 by screws 59, and the opening degree of the reed valve 58 is a valve stopper 60. Regulated by. Therefore, in the present embodiment, the valve 53 is arranged in such a direction that the reed valve 58 opens and closes in the vertical direction.
[0039]
The valve unit 50 configured as described above is installed on the transmission case 14 with a damper 61 interposed therebetween as shown in FIG. 8, and at the rear end portion of the lower case 51B as shown in FIG. The bolt 62 passing through the circular hole 51c of the projecting flange 51b is fastened to the boss 14b projecting from the upper surface of the transmission case 14, and is fixed to the transmission case 14. A grommet 63 is fitted on the periphery of the circular hole 51c of the flange 51b.
[0040]
On the other hand, as shown in FIGS. 7 and 8, a plug joint 64 that opens toward the rear of the vehicle body is attached to the opening 14 c formed in the upper front portion of the transmission case 14. The suction duct 51a protruding from the lower case 51B of the valve unit 50 is connected by a flexible hose 65. In addition, the plug 66 is inserted into the plug joint 64 and the suction duct 51 a by a clip 66.
[0041]
Further, as shown in FIG. 7, one end of a flexible hose 67 is inserted into the discharge duct 51e protruding from the upper case 51A of the valve unit 50 and tightened by a clip 68. The other end extends from the valve unit 50 across the transmission case 14 to the right side of the vehicle body, is inserted into a metal AIS pipe 69 arranged on the right side of the vehicle body, and is fastened by a clip 70. The AIS pipe 69 is opened in the exhaust pipe 16 (see FIG. 1).
[0042]
Thus, according to the present embodiment, fresh air is introduced into the front cover 9 from the opening on the top surface of the front cover 9 and the space formed by the footrest 11 and the under cover 29 is directed toward the rear of the vehicle body. However, even in the off-road scooter type motorcycle 1, the intrusion of mud and dust into the clean room S defined below the footrest 11 is Since it is prevented by the panels 30, 31, etc., only clean fresh air in the clean room S is sucked into the air cleaner 36 of the unit swing type engine 12 through the intake duct 37 that opens into the clean room S. The fresh air sucked into the air cleaner 36 is purified by passing through a filter element (not shown) built in the air cleaner 36, and a part thereof is guided from the chamber S1 to the transmission case 14 via the fresh air introduction duct 14a. Then, the air is supplied to the inside of the transmission case 14 for cooling, and other fresh air passes from the chamber S2 through the intake pipe 45 to the carburetor 46 to be used for formation of the air-fuel mixture in the carburetor 46.
[0043]
A part of the fresh air used for cooling the transmission case 14 is introduced into the exhaust pipe 16 by the AIS, and is used for burning unburned components in the exhaust gas flowing through the exhaust pipe 16. That is, the fresh air in the transmission case 14 is drawn by the negative pressure generated in the exhaust pipe 16 from the suction duct 51a to the lower chamber S4 in the valve unit 50 constituting the AIS through the plug joint 64 through the hose 65. Inflow. The fresh air that has flowed into the lower chamber S4 of the valve unit 50 passes through the filter element 52 to be purified, reaches the upper chamber S3, is discharged from the discharge duct 51e to the outside of the valve unit 50 through the reed valve 58, The unburned components in the exhaust gas introduced into the exhaust pipe 16 through the hose 67 and the AIS pipe 69 and flowing through the exhaust pipe 16 are used for combustion. When the pressure in the exhaust pipe 16 is positive, the reed valve 58 built in the valve unit 50 is closed, so that the backflow of the exhaust gas flowing through the exhaust pipe 16 to the valve unit 50 side is prevented. .
[0044]
As described above, fresh air is supplied into the exhaust pipe 16 by the AIS, and unburned components in the exhaust gas flowing through the exhaust pipe 16 are burned, so that the exhaust gas discharged from the exhaust pipe 16 is purified. The
[0045]
Thus, in the present embodiment, the valve 53 built in the valve unit 50 constituting the AIS is arranged in such a direction that the reed valve 58 opens and closes in the vertical direction, so that the height of the valve unit 50 is kept low. Therefore, the compact valve unit 50 having a low height can be rationally arranged on the transmission case 14 of the unit swing type engine 12 while avoiding interference with other parts.
[0046]
Further, since the valve unit 50 is arranged on the transmission case 14 arranged on the left side of the vehicle body, the exhaust pipe 16 and the muffler 17 arranged on the opposite side (right side) may become an obstacle to the maintenance of the valve unit 50. Therefore, replacement of the filter element 52 of the valve unit 50 is facilitated, and maintenance is improved.
[0047]
Further, in the AIS, the problem of intake noise does not occur because fresh air is sucked in from the transmission case 14, and the filter element 52 of the valve unit 50 is small in order to suck fresh air once purified by the air cleaner 36. Can be
[0048]
In the present embodiment, a scooter type motorcycle equipped with an AIS that introduces secondary air into the exhaust pipe of a two-cycle engine has been described. However, the present invention provides an exhaust passage formed in a cylinder head of a four-cycle engine. Of course, a scooter type motorcycle equipped with an AIS for introducing secondary air is also included in the application.
[0049]
【The invention's effect】
As is apparent from the above description, according to the present invention, the unit swing type engine configured by integrating the engine and the transmission case including the automatic transmission and the power transmission mechanism is disposed below the seat. In addition, in a scooter type motorcycle equipped with an air intake system for introducing fresh air into the exhaust system of the engine, a valve unit constituting the air intake system is disposed on a transmission case of the unit swing type engine, Since the check valve built in the valve unit is arranged in such a direction that the valve body opens and closes in the vertical direction, a compact and rational arrangement of the air intake system can be realized, and the height of its components can be kept low. The effect is obtained.
[Brief description of the drawings]
FIG. 1 is an overall side view of a scooter type motorcycle according to the present invention.
FIG. 2 is a partial side view of the lower part of the footrest showing the structure of the fresh air introduction system of the unit swing type engine.
FIG. 3 is a partial plan view of the lower part of the footrest showing the structure of the fresh air introduction system of the unit swing type engine.
FIG. 4 is a partial plan sectional view of a unit swing type engine showing a configuration inside a transmission case.
FIG. 5 is a side view of the transmission case.
6 is an enlarged sectional view taken along line AA in FIG.
FIG. 7 is a partially broken plan view of a unit swing type engine showing the configuration and arrangement of an air intake system (AIS).
8 is a view in the direction of arrow B in FIG.
FIG. 9 is a cutaway side view of a valve unit constituting an air intake system (AIS).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Scooter type motorcycle 10 Seat 12 Unit swing type engine 13 Engine 14 Transmission case 16 Exhaust pipe 50 Valve unit 53 Valve (check valve)
58 Reed valve

Claims (1)

Air for introducing fresh air into the exhaust system of the engine while arranging the unit swing type engine, which is constructed by integrating the engine and the transmission case with built-in automatic transmission and power transmission mechanism, under the seat In a scooter type motorcycle equipped with an intake system,
A valve unit that constitutes the air intake system and includes a check valve having a valve body is disposed in the unit swing type engine, and is disposed in a direction in which the valve body is opened and closed in the vertical direction.
The valve unit has a suction duct for allowing the fresh air to flow into the valve unit, and a discharge duct provided above the suction duct,
The valve body is provided between the suction duct and the discharge duct, and moves upward to open the check valve, and moves downward to close the check valve. Scooter type motorcycle.

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