JP3580375B2 - Swing power unit type small vehicle - Google Patents

Description

[0001]
[Industrial applications]
The present invention can smoothly guide cooling air from a cooling fan directly connected to a crankshaft to a cylinder and a cylinder head of an internal combustion engine, can appropriately cool them, and can compactly mount a swing power unit to a vehicle body. The present invention relates to a small vehicle capable of performing the above.
[0002]
[Prior art]
There is a motorcycle in which a power unit cylinder in which an internal combustion engine and a transmission with a built-in transmission are integrated is directed to the front of the vehicle body, and a power unit is mounted on the vehicle body at the upper part of a crankcase so as to swing up and down. (See JP-A-2-181017).
[0003]
In the embodiment shown in FIGS. 1 to 3 of the above publication, a cooling air intake port is opened on the right side of the cylinder shroud surrounding the cylinder (the side opposite to the left side where the valve train chain is arranged). A radiator for cooling the cylinder head is provided at the cooling air inlet, and an axial cooling fan that is rotationally driven by a crankshaft is provided inside the radiator for cooling the cylinder head. The radiator for cooling the cylinder head is cooled by the sucked cooling air and the cylinder is cooled, and the cylinder head is cooled by the cooling water cooled by passing through the radiator for cooling the cylinder head.
[0004]
[Problem to be solved]
In the above-mentioned publication, it is necessary to pivot the cooling fan in parallel with the crankshaft and to connect the cooling fan to the crankshaft with gears or the like, so that the structure becomes complicated and the weight reduction is difficult.
[0005]
As an improvement, in the embodiment shown in FIG. 4 in which a centrifugal cooling fan is mounted at the shaft end of the crankshaft, the shroud surrounding the centrifugal cooling fan is inevitably increased in diameter, and the power unit is accordingly increased. It was inevitable that the pivot would move upward and the seat height would increase.
[0006]
Further, in the motorcycle described in the above publication, since the intake system is disposed above the cylinder shroud, the fuel tank above the intake system must also be installed at a high position. The seat height had to be high.
[0007]
Means for Solving the Problems and Effects
The present invention relates to an improvement of a swing power unit type small vehicle that overcomes such difficulties, and relates to a swing in which a power unit formed by integrating an internal combustion engine and a transmission with a built-in transmission is vertically swingably mounted on a vehicle body. In a power unit type small vehicle, a cylinder projects from the swing power unit main body in a substantially forward direction of the vehicle body, and a centrifugal cooling fan is attached to a shaft end of a crankshaft, and surrounds the outer periphery of the centrifugal cooling fan to the cylinder and the cylinder head. An upper portion of a fan shroud that guides the cooling air protrudes upward from an outer peripheral surface of the internal combustion engine body, and a hanger that supports the swing power unit is located closer to the center in the vehicle width direction than the fan shroud in plan view and in side view. The fan shroud is provided so as to protrude within a range bounded by an outer peripheral edge thereof. That.
[0008]
Since the present invention is configured as described above, the cooling air sucked by the centrifugal cooling fan from the opening of the fan shroud flows in the tangential direction of the fan and is guided to the cylinder and the cylinder head. Is cooled by the cooling air.
[0009]
Further, in the present invention, since the fan shroud is formed so that the upper portion of the fan shroud protrudes upward from the outer peripheral surface of the internal combustion engine body, the diameter of the fan shroud is increased, and the cooling air is efficiently supplied to the cylinder and the cylinder head. And the cylinder and the cylinder head are sufficiently cooled.
[0010]
Furthermore, in the present invention, the hanger supporting the swing power unit is positioned closer to the center in the vehicle width direction than the fan shroud in a plan view, and protrudes in a range bounded by the outer peripheral edge of the fan shroud in a side view. With the outer diameter of the fan shroud kept large, the hanger can be brought as close as possible to the vertical center position of the power unit, so that the seat height can be reduced and the space between the internal combustion engine and the seat can be increased. The capacity of the container, fuel tank and the like in the space can be increased.
[0011]
Still further, by configuring the present invention as described in claim 2, the hanger pin can be inserted through the hanger pin fitting opening without being hindered by a fan shroud extending upward from the outer peripheral surface of the internal combustion engine body. Can be inserted into the hanger and the maintenance of the small vehicle can be performed very easily. After the hanger pin is inserted, the lid is fitted into the hanger pin fitting opening. The combination allows the fan shroud to be hermetically sealed, thereby preventing the cooling air from leaking.
[0013]
【Example】
An embodiment of the present invention illustrated in the drawings will be described.
The swing power unit 2 mounted on the scooter type motorcycle 1 (a three-wheeled or four-wheeled vehicle having one or two front wheels and two rear wheels is also possible) has a cylinder block 14 and a cylinder head 15 located in front of the vehicle. An air-cooled internal combustion engine 3 oriented slightly upward and a V-belt continuously variable transmission 4 oriented rearward from the left side of the air-cooled internal combustion engine 3 are integrally connected to each other to form a V-belt continuously variable transmission. A rear wheel 6 is integrally fitted to the output shaft 5 of the engine 4, and a pair of right and left hangers 7 located above a crankcase portion of the air-cooled internal combustion engine 3 project downward from a rear frame 8 of the scooter type motorcycle 1. The swing power unit 2 is connected to the rear portion of the rear frame 8 via a shock absorber 11 while being attached to the brackets 9l and 9r so as to be swingable up and down via a link 10. Swing power unit 2 in accordance with the undulation of the road surface when the line is as capable of swinging up and down.
[0014]
As shown in FIG. 4, the swing power unit 2 includes a left crankcase 12 serving also as a crankcase of the air-cooled internal combustion engine 3 and a transmission case of the V-belt continuously variable transmission 4, a right crankcase 13, A cylinder block 14 integrally connected to the left crankcase 12 and the right crankcase 13, a cylinder head 15 connected to the top end of the cylinder block 14, and a transmission removably mounted on the left side of the left crankcase 12. The fan cover 18 is divided into a machine cover 16 and a right cover 17 connected to the right side of the right crankcase 13, and a fan cover 18 covering a centrifugal cooling fan 31 described later is detachably mounted on the right side of the right cover 17. Upper and lower cylinder shrouds 19 and 20 that cover the block 14 and the cylinder head 15 are cylinder heads. It is detachably mounted to the left crank case 12 and the fan cover 18 together are fitted with the projection 21 of 15.
[0015]
Further, a drive pulley 23 of the V-belt type continuously variable transmission 4 is provided at the left end of a crankshaft 22 rotatably supported by the left crankcase 12 and the right crankcase 13. A driven pulley 25 is provided via a centrifugal clutch (not shown) on a driven shaft 24 pivotally supported at the rear, and a V-belt 26 is bridged between the driving pulley 23 and the driven pulley 25. As the speed increases, the speed ratio of the V-belt continuously variable transmission 4 decreases steplessly, and the centrifugal clutch is automatically engaged when a predetermined number of revolutions is reached, so that the power of the air-cooled internal combustion engine 3 is increased. Is transmitted to the rear wheels 6 via the V-belt type continuously variable transmission 4.
[0016]
Further, a large number of cooling fins 27 and 28 are formed at predetermined intervals on the outer peripheral surfaces of the cylinder block 14 and the cylinder head 15, and the right end of the crankshaft 22 is integrally provided with the rotor 30 of the generator 29 in the right cover 17. , And a centrifugal cooling fan 31 is integrally attached to the rotor 30 within the fan cover 18.
[0017]
As shown in FIG. 5, the crankshaft 22 and the centrifugal cooling fan 31 rotate clockwise as viewed from the right side of the vehicle body, and the upper half of the cooling air passage 32 in the fan cover 18. The partition wall is formed spirally in a direction away from the center of the crankshaft 22 in a clockwise direction from the rear part to the front part via the upper part, and the right cover 17 is also partially missing in the right cover 17 along the spiral direction. A space 34 having substantially the same shape as the cooling air passage 32 is formed by the cooling air passage 33, and the upper right side of the cooling fin 27 of the cylinder block 14 extends along the spiral direction X of the cooling air passage 32 as shown in FIG. 5. After being inclined downward as it moves forward, it is curved so as to point downward.
[0018]
A suction opening 35 of the fan cover 18 is formed in a cylindrical shape concentric with the centrifugal cooling fan 31, and a louver 36 is fitted into the suction opening 35.
[0019]
The lower surface of the cylinder shroud 20 further has an exhaust port 37 opening rightward. The exhaust port 37 is sucked from the intake opening 35 of the fan cover 18 located on the right side of the swing power unit 2 and is swirled by the centrifugal cooling fan 31. The cooling air introduced into the space surrounded by the cylinder shrouds 19 and 20 from the cooling air passage 32 contacts the cooling fins 27 and 28 and exchanges heat with the cooling fins 27 and 28, and then is discharged from the lower exhaust port 37. ing.
[0020]
Further, as shown in FIG. 6, a bolt insertion hole 38 is formed on the left side wall of the right cover 17 at a position on the line connecting the centers of the left and right hangers 7 above the spiral cooling air passage 32. A bolt insertion hole 39 is also formed in the fan cover 18 at an extension thereof, and a rubber grommet 40 serving as a lid is fitted into the bolt insertion hole 39.
[0021]
Next, a link 10 for connecting the bracket 9 of the rear frame 8 and the hanger 7 of the swing power unit 2 includes a sleeve 43 surrounding a hanger bolt 41 penetrating the pair of right and left hangers 7, and a lower edge fixed to the sleeve 43. A connecting plate 44, a curved connecting tube 45 having a central curved portion integrally fixed to the connecting plate 44, a swing lever 46 integrally fixed to a left end of the curved connecting tube 45, and a swing lever 46. A shock absorbing rubber 47 provided at both ends of 46 and in contact with the left end 9l, a swing base 48 integrally fixed to the right end of the curved connecting pipe 45, and fitted to the swing lever 46 and the swing base 48, respectively. The buffer bush 49 is integrally connected to the brackets 91 and 9r, and the buffer bush 52 integrally fitted to the left and right hangers 7 is provided with the cushion bush 49. It is integrally connected to the sleeve 43 of the link 10 at the nut 42 screwed on the hanger bolt 41 and the hanger bolt 41 passing through the buffer bush 52 and the sleeve 43 of the guard 7.
[0022]
Note that an intake system 53 such as a carburetor is disposed above the cylinder shroud 19, and the intake system 53 does not contact the upper curved bottom 55 of the helmet container 54 above the intake system 53.
Further, a fuel tank 56 is disposed behind the helmet container 54.
[0023]
Since the embodiment illustrated in the drawings is configured as described above, when the air-cooled internal combustion engine 3 is in the operating state, the centrifugal cooling fan 31 rotates clockwise in FIGS. The cooling air, which is rotationally driven, is sucked from the suction opening 35 of the fan cover 18 on the right side of the vehicle body, is sent into the cylinder shrouds 19 and 20 from the lower part through the rear part and the upper part in the cooling air passage 32, The block 14 touches the cooling fins 27 and 28 of the cylinder head 15 and is discharged from the exhaust port 37 of the cylinder shroud 20 toward the right side of the vehicle body. The head 15 is cooled.
[0024]
The cooling air passage 32 is located further to the right outside the hanger 7 on the right side and extends upward without interference with the hanger 7, and the end of the cooling air passage 32 near the cylinder shrouds 19 and 20 is sufficiently wide. A large flow of cooling air can smoothly flow into the cylinder shrouds 19 and 20 without being disturbed, the flow path resistance is small, and the cooling performance is extremely high.
[0025]
Further, since the hanger 7 can be disposed below the upper edge of the swing power unit 2 , that is, closer to the center in the vertical direction , regardless of the cooling air passage 32 extending upward, the bottom 55 of the helmet container 54 is also connected to the curved connecting pipe 45 of the link 10. Helmet container 54 can be increased, and the height of seat 57 can be reduced.
[0026]
Furthermore, bolt insertion holes 38 and 39 are formed in the right cover 17 and the fan cover 18 on the center line of the left and right hangers 7, and the rubber grommet 40 is fitted in the bolt insertion holes 39 so as to be freely fitted. Therefore, by removing the rubber grommet 40, penetrating the hanger bolt 41 through the bolt insertion holes 39 and 38, the buffer bush 52 of the hanger 7, and the sleeve 43 of the link 10, and screwing the nut 42 to the hanger bolt 41, Since the hanger 7 of the swing power unit 2 can be attached to the rear frame 8 via the link 10, the hanger 7 can be connected to the body of the scooter type motorcycle 1 without removing the right cover 17 and the fan cover 18. Very easily, and a rubber grommet 40 is fitted into the bolt insertion hole 39. In Mudake, it is possible to easily seal the cooling air passage 32.
[0027]
In addition, the road surface reaction force applied to the rear wheel 6 accompanying the traveling of the scooter type motorcycle 1 is transmitted from the shock absorber 11 and the hanger 7 to the bracket 9 of the rear frame 8 via the link 10, and the shock and vibration are damped. The device 11, the buffer bush 52 of the hanger 7, the buffer rubber 47, and the buffer bush 49 are sufficiently absorbed.
[Brief description of the drawings]
FIG. 1 is a left side view showing a rear half of a swing power unit type small vehicle according to an embodiment of the present invention.
FIG. 2 is a right side view illustrating a rear half of the embodiment.
FIG. 3 is a plan view of the embodiment with a vehicle body cover removed.
FIG. 4 is a cross-sectional plan view of the air-cooled internal combustion engine of the embodiment.
FIG. 5 is an enlarged right side view of a main part of FIG. 2 with a fan cover removed.
FIG. 6 is a vertical sectional front view taken along the line VI-VI of FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Scooter type motorcycle, 2 ... Swing power unit, 3 ... Air-cooled internal combustion engine, 4 ... V-belt type continuously variable transmission, 5 ... Output shaft, 6 ... Rear wheel, 7 ... Hanger, 8 ... Rear frame, 9 ... Bracket, 10 link, 11 shock absorber, 12 left crankcase, 13 right crankcase, 14 cylinder block, 15 cylinder head, 16 transmission cover, 17 right cover, 18 fan cover, 19 , 20 ... cylinder shroud, 21 ... protrusion, 22 ... crankshaft, 23 ... drive pulley, 24 ... driven shaft, 25 ... driven pulley, 26 ... V belt, 27, 28 ... cooling fins, 29 ... generator, 30 ... Rotor, 31: centrifugal cooling fan, 32: cooling air passage, 33: partition wall, 34: space, 35: suction opening, 36: louver, 37: exhaust port, 38, 39 Bolt insertion hole, 40: rubber grommet, 41: hanger bolt, 42: nut, 43: sleeve, 44: connecting plate, 45: curved connecting pipe, 46: swing lever, 47: cushion rubber, 48: swing base Reference numerals 49, buffer bush, 50, bolt, 51, nut, 52, buffer bush, 53, intake system, 54, helmet container, 55, bottom, 56, fuel tank, 57, seat.

Claims (2)

In a swing power unit type small vehicle in which a power unit formed by integrating an internal combustion engine and a transmission with a built-in transmission is vertically swingably mounted on a vehicle body, a cylinder is directed substantially forward of the vehicle body from the swing power unit body. A centrifugal cooling fan is mounted on the shaft end of the crankshaft, and an upper portion of a fan shroud that surrounds the outer periphery of the centrifugal cooling fan and guides cooling air to the cylinder and the cylinder head projects upward from the outer peripheral surface of the internal combustion engine body. The hanger supporting the swing power unit is located closer to the center in the vehicle width direction than the fan shroud in plan view and protrudes in a range bounded by the outer peripheral edge of the fan shroud in side view. Swing power unit type small vehicle. On the outer peripheral surface of the shroud, a hanger bolt fitting opening is formed on a center line of the hanger, and a lid is removably fitted into the hanger bolt fitting opening. 2. The swing power unit type small vehicle according to claim 1, wherein:

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