JP2957680B2 - Motorcycle with swing power unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a motorcycle having a swing type power unit in which a power unit including an engine, a power transmission device and a drive wheel is vertically swingably connected to a vehicle body frame, and is particularly provided in an exhaust pipe of the engine. The present invention relates to an arrangement structure of an exhaust gas purification device to be used.

[Prior art]

2. Description of the Related Art Generally, an engine mounted on a motorcycle or the like is equipped with an exhaust purification device in a form provided in an exhaust pipe connected to the engine. This exhaust gas purification device is usually provided with a catalytic converter in which a granular or honeycomb-shaped catalyst body is packed in a muffler-shaped container, in the middle of an exhaust pipe, and through which exhaust gas passes in the same manner as a filter or the like.
HC is a air pollutants, CO, and NO _x and the like, harmless H ₂ O, C
It is designed to chemically change to O ₂ , N _2, etc. As this exhaust gas purifying apparatus, for example, Japanese Utility Model Publication No. 61-49
As shown in Japanese Patent Publication No. 4 (2004), a honeycomb body having the above-mentioned honeycomb-shaped catalyst body mounted inside a flat purification column,
The short axis of the purifier is arranged along the vertical direction in the middle of the exhaust pipe at the lower part of the engine, so that the minimum ground clearance of the motorcycle itself is as high as possible, and there is little effect when tilting the body. There is something.

[Problems to be solved by the invention]

However, like the motorcycle shown in the above publication,
Even if the exhaust purification device is mounted on the exhaust pipe so that the minimum ground clearance can be as high as possible, the minimum ground clearance is still the distance between the exhaust purification device and the road surface. That is, the exhaust gas purification device is most susceptible to road surface interference. In addition, a power unit including an engine, a power transmission device and driving wheels, which is often found in a scooter type motorcycle, is connected to a body frame so as to be swingable in a vertical direction. When applied to a motorcycle having a unit, the exhaust pipe connected to the engine also swings together with the power unit, so that the exhaust purification device easily contacts the road surface, and as a result, the exhaust purification device is likely to be damaged. This tendency is remarkable in a scooter-type motorcycle in which a vehicle body is small and small-diameter wheels are mounted. The present invention has been made in view of such circumstances, and in a motorcycle including a swing-type power unit, an exhaust purification device provided in an exhaust pipe is configured to reduce interference from a road surface due to rocking of the power unit. It is an object of the present invention to provide a motorcycle having a swing-type power unit which is not affected and therefore is prevented from being damaged.

[Means for Solving the Problems]

The present invention has been made to achieve the above object, and an engine to which an exhaust pipe is connected, a power transmission device that transmits the power of the engine to driving wheels, and a power unit including the driving wheels are provided. A motorcycle provided with a swing type power unit, which is swingably connected to a vehicle body frame in a vertical direction and the exhaust pipe is provided with an exhaust purification device in the middle of the exhaust pipe; The exhaust gas purification device is disposed at a tip end of an exhaust pipe main body connected to a cylinder block and continuously extending rearward, and is disposed substantially above a center line extending in the front-rear direction of the power unit in a side view. The pipe main body extends to a substantially central portion in a side view of the muffler, and the exhaust gas purification device is arranged so as to be shifted from a center position of the muffler in a plan view toward a vehicle body center. To have.

[Action]

According to the motorcycle including the swing-type power unit of the present invention, even when the power unit swings up and down during traveling, the exhaust gas purification device mounted on the exhaust pipe is unlikely to receive interference from the road surface. For this reason, the exhaust gas purification device is prevented from being damaged, and its function is maintained for a long time.

【Example】

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an overall side view of a scooter type motorcycle provided with a swing type power unit to which one embodiment is applied. In FIG. 1, reference numeral 1 denotes a body frame extending rearward from the front (left side in the figure) of the body, 2 denotes the engine,
Reference numeral 3 denotes a power transmission device, and reference numeral 4 denotes a rear wheel which is a drive wheel having a tire 4b mounted on a wheel 4a. The engine 2, the power transmission device 3 and the rear wheel 4 are configured as a swing type power unit 5. The power unit 5 is connected to a rear portion of the vehicle body frame 1 by a link mechanism 6 including a bracket 6a and a link 6b so as to be vertically swingable, and is supported by the vehicle body frame 1 via a suspension 7. I have. In FIG. 1, reference numeral 8 denotes a steering wheel, 9 denotes a front wheel having wheels 9a and tires 9b mounted thereon, 10 denotes a front fork mounted on the vehicle body frame 1 to support the front wheels, 11 denotes a seat whose front end is hinged and can be opened and closed. , 12 is a storage case such as a helmet provided under the seat 9, 13 is a fuel tank,
14 is a body cover, and 15 is a rear fender. The engine 2 is a two-cycle single cylinder type as shown in FIGS.
And a cylinder comprising a cylinder block 17a and a cylinder head 17b integrally fixed to the crankcase 16.
17b, a crankshaft 19 rotatably supported on a crankcase 16 via a bearing 18, and a slidably fitted crankshaft 19 in a cylinder block 17a.
A piston 21 connected to the cylinder head 17 via a connecting rod 20, and a plug 22 mounted on the cylinder head 17b.
In this case, the cylinder 17 of the engine 2 is inclined forward of the vehicle body. A rotor 23b of an AC generator 23 including a stator 23a and a rotor 23b is integrally fixed to a protruding end of the crankshaft 19 from the crankcase 16 on the right side of the vehicle body (the upper side in FIG. 3). And on the outer surface of this rotor 23b,
A cooling fan 24 having a fin 24b formed on a peripheral outer surface of a disk-shaped base 24a is integrally fixed. Note that the stator 23a is fixed to the crankcase 16. The engine 2 is entirely housed in a shroud 25. At a position of the shroud 25 facing the cooling fan 24, an intake port 25a is formed in a slit shape. When the engine 2 is operated, That is, when the crankshaft 19 rotates, the cooling fan 24 rotates, and outside air is introduced into the shroud 25 from the intake port 25a, so that the engine 2 is cooled. That is, the engine 2 is a forced air cooling type in which the engine 2 is cooled by the cooling fan 24 in the operating state. A carburetor 26 and an air cleaner, which constitute an intake system, are provided behind the cylinder block 17a of the engine 2.
An exhaust pipe 28 constituting an exhaust system is connected to the front of the cylinder block 17a. A secondary air supply path 29 that supplies secondary air into the exhaust pipe 28 is connected near the connection of the exhaust pipe 28 to the cylinder block 17a. The secondary air supply path 29 is an air cleaner that is fixed to the front outer surface of the storage case 12 and communicates with the storage case 12.
30, a reed valve 31 connected to the downstream side of the air cleaner 30, a supply pipe 32 connected to the exhaust pipe 28 in the vicinity of a connection part to the cylinder block 17a and extending upward, and a supply pipe 32 and the reed valve 31. And a flexible bendable hose 33 connecting the downstream side of the hose. According to the secondary air supply path 29, when the engine 2 is operated and the exhaust gas flows from the engine 2 (cylinder 17) to the exhaust pipe 28, the inside of the supply pipe 32 and the hose 33 are in a negative pressure state, so that the lead The valve 31 is opened, and the air in the storage case 12 is introduced into the exhaust pipe 28 through the air cleaner 30, the reed valve 31, the hose 33, and the supply pipe 32. Then, the unburned gas flowing through the exhaust pipe 28 immediately after being discharged from the engine 2 becomes
Reacts with the introduced air and burns. This prevents unburned gas from being discharged to the outside. Next, the power transmission device 3 will be described with reference to FIG. 3. The power transmission device 3 is a conventionally known power transmission device, and includes a case body 34a provided integrally with the crankcase 16 of the engine 2 and a case body 34a. A transmission system 35 is provided in a transmission case 34 including a side cover 34b for closing the side opening of the transmission case 35. This transmission system 35 is fixed to a protruding end of the crankshaft 19 of the engine 2 on the left side of the vehicle body (lower side in FIG. 3), and has a centrifugal variable diameter drive pulley 36 which rotates integrally with the crankshaft 19; A driven pulley 37 having a variable-diameter structure disposed behind the pulley 36 (right side in FIG. 3), and both pulleys
Drive belt 38 of V belt structure wound between 36 and 37
An automatic centrifugal clutch mechanism 39 provided on the side cover 34b side (left side of the vehicle body) of the driven pulley 37 and transmitting the rotation of the driven pulley 37 to the rear wheel 4, and provided between the driven pulley 37 and the rear wheel 4. , The power transmission shaft 40 of the clutch mechanism 39 and the rear wheel 4
A plurality of reduction gear groups (reduction mechanisms) 42 connecting the axle 41
It is composed of According to the transmission system 35, when the drive pulley 36 rotates together with the crankshaft 19, the rotation is transmitted to the driven pulley 37 by the drive belt 38, and the crankshaft 19
When the rotation of the vehicle becomes higher than a certain value, the clutch mechanism 39 is engaged and the power transmission shaft 40 rotates, and the rotation is transmitted to the axle 41 of the rear wheel 4 via the reduction gear group 42. Has become. In the drive pulley 36, as the speed increases, that is, as the rotation of the crankshaft 19 increases, the weight roller 43 provided on the drive pulley 36 increases.
Due to the centrifugal force, the width of the drive pulley 36 is reduced, and the effective radius around which the drive belt 38 is wound around the drive pulley 36 is increased. In addition, the drive belt 38 accordingly moves forward as a whole. At this time, the width of the driven pulley 37 is increased, and the effective radius of the drive belt 38 wound around the driven pulley 37 is reduced. With this operation, the effective radius of the drive belt 38 wound around the drive pulley 36 and the driven pulley 37 changes due to the change in the rotation speed of the crankshaft 19, and the rotation is automatically performed according to the rotation of the crankshaft 19, that is, the traveling speed. The speed is changed. The exhaust pipe 28 is connected to the front of the cylinder block 17a of the engine 2 and once extends downward and forward, bends to the right side of the vehicle body, extends rearward of the vehicle body right below the engine 2 and extends rearward of the vehicle body 2 below the engine 2. After passing through the exhaust pipe main body 28a, which rises substantially along the rear part of the engine 2 and further extends rearward, the tip end part of which covers the rising part of the exhaust pipe main body 28a whose diameter is enlarged like a trumpet. The silencer 28b is connected to the silencer 28b, and a silencer main body 44 having an exhaust duct 44a is attached to the end of the silencer 28b. In the muffler 28b and the muffler main body 44, a partition plate 45 and partition plates 46 and 47 for separating the upstream side and the downstream side are provided, respectively. Two exhaust chambers 48a and 48b are formed, and third and fourth exhaust chambers 49a and 49b are formed in the muffler main body 44, respectively.
The third exhaust chamber 49a and the fourth exhaust chamber 49b are provided with a partition plate.
The holes 47 (not shown) communicate with each other. The first exhaust chamber 48a and the second exhaust chamber 48b communicate with each other via a communication pipe 50, the second exhaust chamber 48b and the fourth exhaust chamber 49b communicate with each other via a communication pipe 51, and the third exhaust chamber 48b communicates with the third exhaust chamber 49b. Exhaust chamber 4
9a and the inside of the duct 44a at the end of the silencer main body 44 are communicated by a communication pipe 52. As a result, the exhaust gas generated in the engine 2 flows from the exhaust pipe main body 28a to the first exhaust chamber 48a →
Communication pipe 50 → second exhaust chamber 48b → communication pipe 51 → fourth exhaust chamber 4
The air is discharged from the duct 44a to the outside through a maze-like path such as 9b → third exhaust chamber 49a → communication pipe 52. Now, the exhaust pipe 28 is provided with an exhaust purification device 53 according to the present invention.
Is equipped. The exhaust gas purifying device 53 includes a first catalytic converter 54 provided at a bent portion which is a front end of the exhaust pipe main body 28a, and a second catalytic converter 55 provided at a front end of the exhaust pipe main body 28a.
Consists of The first catalytic converter 54 has a number of holes formed in the exhaust pipe body 28.
a, a cloth body (cloth) 54a carrying a catalyst substance is wound around the exhaust pipe main body 28a in a spiral shape so as to cover this hole (not shown), and is provided with a so-called cross catalyst body. It is a thing. The second catalytic converter 55 is a honeycomb-shaped multi-channel member made of ferritic stainless steel in which a plurality of honeycomb-shaped passages are formed in the axial direction, or a flat plate and a corrugated plate of the same material are superposed to form a column. The metal catalyst body 55a is formed by winding and tightening, and this metal catalyst body 55a is attached to the end of the exhaust pipe body 28a by the exhaust pipe body 28a.
And is mounted coaxially. By the first and second catalytic converters 54 and 55, the exhaust gas of the engine 2 flowing through the exhaust pipe main body 28a is:
Air pollutants contained therein (HC, CO, NO _x, etc.),
Chemically changes to harmless H ₂ O, CO ₂ , N ₂ etc.
b and is discharged outside through the silencer body 44. The second catalytic converter 55 is provided at the end of the exhaust pipe main body 28a. This position is, as shown in FIG. 2, the center line L of the power unit 5 extending in the front-back direction in a side view. It is located above ₁ . That is, the second catalytic converter 55 is not disposed above than the center line L _1. According to the swing type power unit scooter-type motorcycle provided with the above configuration, the second catalytic converter 55 that is provided on the exhaust pipe 28, the power unit 5, the center line L ₁ extending in side view the front-rear direction It is located above and at a relatively high position. Therefore, even if the power unit 5 swings up and down via the link mechanism 6 while the motorcycle is running, the second catalytic converter 5
The portion around 5 is unlikely to come into contact with the road surface, so that the second catalytic converter 55
There is no risk of damage. As a result, the function of the second catalytic converter 55 is maintained for a long time. 4 and 5 show another embodiment of the present invention. These figures show a swing type power unit 60 provided in a scooter type motorcycle as in the above embodiment. The power unit 60 includes a crankcase 61, a cylinder 62 including a cylinder block 62a and a cylinder head 62b,
Crankshaft 63 supported by crankcase 61, base 64a and fin 64b that rotate integrally with crankshaft 63
And a power transmission device 68 for transmitting the power of the engine 66 to a rear wheel 67 including wheels 67a and tires 67b. The power unit 60 is connected to the vehicle body frame 71 via a link mechanism 70 including a bracket 70a formed below a front portion of a transmission case 69 of the power transmission device 68 and a link 70b attached to the vehicle body frame 71. It is supported swingably up and down. In this case, the cylinder 62 of the engine 66 is slightly inclined rearward of the vehicle body, and is entirely stored in the shroud 72. In the shroud 72, similarly to the above embodiment, an intake port 72a of the cooling fan 64 is formed in a slit shape. At the rear of the cylinder block 62a of the engine 66, a carburetor (not shown) constituting an intake system and an air cleaner
An exhaust pipe 74 constituting an exhaust system is connected to the front part. The exhaust pipe 74 includes a pipe-shaped upstream exhaust pipe 74a, an intermediate exhaust pipe 74b, and a downstream exhaust pipe 7 having a flared shape.
4c is connected, and as a whole, once extends forward and downward from a connection portion to the cylinder block 62a, then bends to the right side of the vehicle body, extends rearward of the vehicle body right below the engine 66, and passes below the engine 66. Afterward, the engine 66 extends rearward while rising upward on the rear side of the engine 66. The exhaust pipe 74 covers the downstream exhaust pipe 74c and
5 is connected. An exhaust duct 75a is provided at the end of the silencer 75. At the end of the exhaust pipe 74c on the downstream side of the exhaust pipe 74, a metal catalyst body 77a similar to the second catalytic converter 55 of the above-described embodiment is provided as an exhaust purification device 76.
Is installed. The exhaust gas of the engine 66 enters the silencer 75 through the exhaust pipe 74, and is then exhausted from the exhaust duct 75a. Now, in the present embodiment, the catalytic converter 77 mounted on the exhaust pipe 74 is, as shown in FIG.
Of, are positioned substantially above the center line L ₂ extending in side view the front-rear direction. That is, the catalytic converter 77 is disposed above the the center line L _2. Therefore, similarly to the above embodiment, even if the power unit 60 swings up and down, the catalytic converter 77
The portion around the catalytic converter 77 in the above is unlikely to come into contact with the road surface, and therefore, there is no possibility that the catalytic converter 77 provided therein will be damaged. as a result,
The function of the catalytic converter 77 (exhaust gas purifying device 76) is maintained for a long time.

【The invention's effect】

As described above, according to the motorcycle including the swing type power unit of the present invention, an engine to which an exhaust pipe is connected, a power transmission device that transmits the power of the engine to driving wheels, A power unit comprising a swing type power unit, which is swingably connected to a vehicle body frame in a vertical direction, and the exhaust pipe is provided with an exhaust purification device in the middle thereof. Since the exhaust gas purifying device mounted on the exhaust pipe is disposed substantially above a center line extending in the front-rear direction of the power unit in a side view, even if the power unit swings up and down during traveling, the exhaust pipe is attached to the exhaust pipe. The exhaust gas purification device to be installed is hardly affected by interference from the road surface, so that the exhaust gas purification device is prevented from being damaged and its function is maintained for a long time. Further, since the exhaust gas purification device is disposed at the end of the exhaust pipe main body connected to the cylinder block and continuously extending rearward, the catalytic action can be promoted while keeping the exhaust gas touching the catalyst at a high temperature. Since the exhaust pipe main body extends to the approximate center of the digestive organ in side view,
The heat generated from the catalyst can prevent the muffler outer plate from becoming hot. Further, since the exhaust gas purification device is disposed so as to be shifted from the center position of the muffler toward the center of the vehicle body in plan view, the heat generated from the exhaust gas purification device causes the outer plate of the muffler, particularly, the outer plate outside the vehicle body to become hot. Can avoid
As a result, it is possible to prevent the heat damage caused by the exhaust gas purification device from extending to the outside of the vehicle body.

[Brief description of the drawings]

1 to 3 show an embodiment in which the present invention is applied to a scooter type motorcycle. FIG. 1 is an overall side view, FIG. 2 is a side view of a power unit, and FIG. 4 and 5 are views showing another embodiment of the present invention. FIG. 4 is a side view of a power unit, and FIG. 5 is a partially sectional plan view of the power unit. . 1, 71 ... body frame, 2, 66 ... engine, 3, 68
… Power transmission device, 4, 67… Rear wheel (drive wheel), 5, 60
… Power unit, 28, 74… Exhaust pipe, 53, 76… Exhaust gas purifier, L ₁ , L ₂ … Center line.

Claims (1)

(57) [Claims] An engine to which an exhaust pipe is connected, a power transmission device for transmitting the power of the engine to driving wheels, and a power unit including the driving wheels can swing vertically with respect to a body frame. The exhaust pipe is connected to a motorcycle provided with a swing-type power unit equipped with an exhaust purification device in the middle of the exhaust pipe. The exhaust purification device mounted on the exhaust pipe is connected to a cylinder block. Along with being disposed at the tip of an exhaust pipe main body extending continuously rearward, and disposed substantially above a center line extending in the front-rear direction of the power unit in a side view, the exhaust pipe main body extends to a substantially central portion in a side view of the muffler. An automatic exhaust system provided with a swing-type power unit, wherein the exhaust gas purifying device is extended and is displaced from a center position of the muffler toward a center of the vehicle body in a plan view. Car.