JP2011105148A - Power unit for vehicle - Google Patents

Abstract

In a power unit for a vehicle in which an internal combustion engine and a power transmission device thereof are integrated and a rear wheel as a drive wheel is swingably supported with respect to a vehicle body, the power unit is reduced in size and appearance is reduced. , Improve the freedom of design.
The power transmission device includes a V-belt continuously variable transmission, a gear reducer linked to a rear axle, and a clutch shaft that serves as an input shaft of the gear reducer, and includes a V-belt continuously variable transmission. The driven pulley shaft is a separate shaft from the clutch shaft, the driven pulley shaft is provided close to the drive pulley shaft, and the power transmission portion from the driven pulley shaft to the clutch shaft is extended forward of the space for housing the gear reducer. Arranged in the outlet.
[Selection] Figure 3

Description

  The present invention relates to a vehicle power unit including a V-belt continuously variable transmission and a gear reducer.

  In the conventional vehicle power unit, the drive pulley and the driven pulley of the V-belt type continuously variable transmission are provided apart from each other in the front and rear, and the starting clutch is provided on the driven pulley shaft. On the left side, the driven pulley portion projects greatly to the side of the transmission case, and on the right side, the gear reducer projects to the inside of the rim portion of the rear wheel (see, for example, Patent Document 1). ).

JP 2006-248524 A (FIG. 3).

  The present invention seeks to improve the degree of design freedom by reducing the size of the power unit and reducing the appearance.

The present invention solves the above problems, and the invention according to claim 1
In a vehicle power unit in which an internal combustion engine and a power transmission device thereof are integrated, and a rear wheel as a drive wheel is swingably supported with respect to a vehicle body,
The power transmission device includes a V-belt continuously variable transmission, a gear reducer connected to a rear axle, and a clutch shaft serving as an input shaft of the gear reducer, and a driven pulley shaft of the V-belt continuously variable transmission. And the clutch shaft are separate shafts, the driven pulley shaft is provided close to the drive pulley shaft, and the power transmission portion from the driven pulley shaft to the clutch shaft is disposed in the front extension of the space for housing the gear reducer The present invention relates to a vehicle power unit.

The invention according to claim 2 is the vehicle power unit according to claim 1,
The power transmission case that accommodates the power transmission device is divided by a gear case, and is divided into a transmission chamber that accommodates a V-belt type continuously variable transmission and a gear chamber that accommodates a gear reducer, and the driven pulley shaft A clutch shaft input gear that receives power from the clutch shaft and a clutch shaft output gear that outputs power from the clutch shaft toward the rear axle are provided on the clutch shaft. The starting clutch extends through the gear case, extends into the transmission chamber, and supports a clutch inner on one shaft and a clutch outer on the other shaft.

The invention according to claim 3 is the power unit for a vehicle according to claim 2,
The clutch shaft that penetrates the gear case and extends to the transmission chamber has an inner shaft supported at both ends by the outer wall body of the gear chamber of the power transmission case and the outer wall body of the transmission chamber of the power transmission case, The outer shaft is supported on the inner shaft, and the outer shaft is supported by the gear case at an intermediate portion thereof.

According to a fourth aspect of the present invention, in the vehicle power unit according to the second aspect,
A breather labyrinth structure for performing breathing in the gear chamber is provided on an upper portion of a portion of the gear chamber that houses a gear for transmitting power from the driven pulley shaft gear to the clutch shaft input gear. .

According to a fifth aspect of the present invention, in the vehicle power unit according to the fourth aspect,
Power transmission between the driven pulley shaft gear and the clutch shaft gear is transmitted through an idle gear, and an oil reservoir is provided on the lower wall of the gear chamber that houses the idle gear. It is what.

The invention according to claim 6 is the power unit for a vehicle according to claim 4,
The gear chamber is characterized in that both upper and lower walls are long in the front-rear direction inclined forward and upward.

The invention according to claim 7 is the vehicle power unit according to claim 1,
The driven pulley shaft is supported by wall bodies on both sides of the gear chamber via ball bearings.

The invention according to claim 8 is the vehicle power unit according to any one of claims 2 to 6,
A pulley chamber for housing the pulley and a clutch chamber for housing the starting clutch are separated by providing a partition, and the starting clutch is lubricated with lubricating oil supplied from a gear chamber. .

In the invention of claim 1,
The power unit can be miniaturized and the appearance can be made slim, and the power transmission unit and the gear reducer can be placed in the same space so that the lubricating structure can be shared and simplified.

In the invention of claim 2,
The gear chamber is a wet space filled with lubricating oil, and the transmission chamber is a dry dry space. The starting clutch can be disposed in a dry transmission chamber without making it wet, and the gear chamber can be downsized and the clutch cooling structure can be simplified.

In the invention of claim 3,
Since the inner shaft is supported at a wide interval and the intermediate portion of the outer shaft is also supported, the rotating shaft can be stably supported and the shaft can be prevented from being enlarged.

In the invention of claim 4,
Since a sufficient distance from each gear of the gear reducer to the breather inlet can be secured, the intrusion of oil mist or the like can be reduced and the breather performance can be improved.

In the invention of claim 5,
Lubricating oil can be fed to the lubrication part of the driven pulley shaft far from the gear reducer with the tooth tip of the idle gear.

In the invention of claim 6,
By using the inclination of the upper and lower walls of the gear chamber, the return of the lubricating oil is improved, and while the lubricating oil is returning, it is made to return while reducing the friction of the rotating part, so the drain return structure is simplified and maintained. Can be improved. The lubricating oil that has returned to the rear oil sump is swept up by the intermediate shaft large-diameter gear and is used for lubrication again.

In the invention of claim 7,
Since the driven pulley shaft can be attached to the wall bodies on both sides of the gear chamber via ball bearings, the driven pulley and the like can be attached, so that the assemblability is improved.

In the invention of claim 8,
Since the pulley chamber is downsized, stagnation of cooling air for cooling the pulley and the like is prevented, and lubricity is improved in the starting clutch.

1 is a side view of a motorcycle according to an embodiment of the present invention. It is a side view of the power unit of the motorcycle. FIG. 3 is a developed sectional view taken along the line III-III in FIG. 2. It is an enlarged plan view of the front half part of a power transmission device. It is an enlarged plan view of the latter half part of a power transmission device. It is the figure which looked at the cross section of the rear part of a power transmission case from the left. It is an enlarged plan view concerning another embodiment of the latter half part of a power transmission device.

  FIG. 1 is a side view of a motorcycle 2 equipped with a power unit 1 according to an embodiment of the present invention. The body frame 3 of the motorcycle 2 includes a main frame 5 that extends rearward and downward from the head pipe 4, a pair of left and right rear frames 6 that are connected to an intermediate portion of the main frame 5 and extend rearward, and the head pipe 4. It is composed of a down frame 7 that extends downward from the rear frame, bends backward, is connected to the lower end of the main frame 5, is further bent upward, and is connected to an intermediate portion of the rear frame 6. The head pipe 4 rotatably supports the front fork 8, a front wheel 9 is pivotally supported at the lower end of the front fork 8, and a steering handle 10 is connected to the upper portion of the front fork 8. A front fender 11 covering the upper portion of the front wheel 9 is supported by the front fork 8. A fuel tank 12 is provided between the main frame 5 and the down frame 7.

  The power unit 1 is suspended from the body frame 3. The power unit 1 includes a front internal combustion engine 13 and a rear power transmission device 14. The internal combustion engine 13 is fixed to the vehicle body frame 3, and the power transmission device 14 swings around a crankshaft 15 of the internal combustion engine 13. Is possible. A rear cushion unit 16 is provided between the rear end portion of the power transmission device 14 and the rear frame 6. A rear wheel 18 is attached to a rear axle 17 provided in the power transmission device 14 and is driven by the power unit 1. An air cleaner 19 is provided on the upper right side of the power unit 1 and is connected to a throttle body 21 connected to the inlet pipe 20 via a connecting pipe 22.

  A storage box 23 for storing a helmet or the like is provided above the power unit 1, and a riding seat 24 is disposed above the storage box 23. A vehicle body cover 25 including a plurality of synthetic resin members is attached to the vehicle body frame 3 to cover the power unit 1 and other devices. The front half of the power transmission device 14 is covered with a front cover 46. A rear fender 26 is provided at the rear of the vehicle. An exhaust pipe 27 and a muffler 28 for an internal combustion engine are provided on the right side of the vehicle. A radiator 29 for cooling the internal combustion engine cooling water is provided on the front surface of the down frame 7.

  FIG. 2 is a side view of the power unit 1. The power unit 1 includes an overhead valve type four-stroke cycle two-cylinder water-cooled internal combustion engine 13 fixed to a vehicle, and a power transmission device 14 supported on the crankshaft 15 so as to be swingable up and down. It has become. The power transmission device 14 includes a V-belt continuously variable transmission 30, a gear reducer 31, and a power transmission unit 80 that transmits power from the V-belt continuously variable transmission 30 to the gear reducer 31. An arrow F points to the front of the power unit 1.

  In the internal combustion engine 13, a cylinder block 34, a cylinder head 35, and a cylinder head cover 36 are connected in an overlapping manner with the cylinder block 34, the cylinder head 35, and the cylinder head cover 36 facing forward slightly from the front end surface of the crankcase 33.

  The power transmission device 14 is accommodated in a power transmission case 37. A plurality of rotating shafts are incorporated in the power transmission case 37. Although details will be described later with reference to FIGS. 3 to 6, a clutch serving as an input shaft for the crankshaft and continuously variable transmission drive pulley shaft 15, continuously variable transmission driven pulley shaft 38, idle shaft 39, and gear reducer 31. A shaft 40, a gear reducer intermediate shaft 41, and a rear axle 17. A drive pulley 42 is provided on the drive pulley shaft 15. A driven pulley 43 is provided on the driven pulley shaft 38. The clutch shaft 40 is provided with a centrifugal start clutch 90. The continuously variable transmission driven pulley shaft 38, the idle shaft 39, the clutch shaft 40, the intermediate shaft 41, and the rear axle 17 are provided with gears that mesh with each other. A rear axle 17 is incorporated in the rear wheel support portion 32, and the power of the internal combustion engine 13 is transmitted to the rear wheel 18 fitted to the rear axle 17.

  3 is a developed sectional view taken along the line III-III in FIG. Arrows L and R represent the left and right sides of the power unit corresponding to the left and right sides of the vehicle. The crankcase 33 is a left-right halved type, and includes a left crankcase 33L and a right crankcase 33R. The crankshaft 15 is rotatably supported by the journal bearing portions 47A and 47B of the left and right crankcases 33L and 33R. Pistons 49 are slidably fitted in a pair of cylinder holes 48 formed in the cylinder block 34, and are connected to the crankshaft 15 via connecting rods 50, respectively. A combustion chamber 51 is formed on the bottom surface of the cylinder head 35 facing the end surface of the piston 49, a spark plug 52 is mounted from the top of the cylinder head cover 36, and its tip faces the combustion chamber 51. As shown in FIG. 2, the cylinder head 35 has an intake port 53 and an exhaust port 54 connected to the combustion chamber 51, and an intake valve 57 that opens and closes the combustion chamber side opening of the intake port 53, and an exhaust port 54. An exhaust valve 58 that opens and closes the combustion chamber side opening is slidably fitted into the cylinder head 35. FIG. 3 shows an exhaust valve 58.

  In FIG. 3, a cam shaft 55 is supported between the cylinder head 35 and the cylinder head cover 36 in parallel with the crankshaft 15, and the intake valve 57 and the exhaust valve 58 are driven to open and close by the cam 56 provided on the cam shaft 55. . The camshaft 55 is cranked by the crankshaft 15 by an endless chain 61 wound between a drive sprocket 59 provided at the right portion of the crankshaft 15 and a driven sprocket 60 provided at the right end of the camshaft 55. The shaft 15 is rotationally driven at a half speed.

  A right crankcase cover 62 is provided outside the right crankcase 33R, and an alternator 65 is composed of a stator 63 fixed to the inner surface of the right crankcase 33R and a rotor 64 surrounding the stator 63 and fixed to the crankshaft 15. Has been. A gear provided adjacent to the AC generator 65 is a starter driven gear 67 that transmits the rotational driving force from the starter motor 66 (FIG. 2) to the crankshaft 15.

  A power transmission case 37 that accommodates the power transmission device 14 of the power unit 1 includes a left power transmission case 37L, a right power transmission case 37R, and a gear case 37G. The right power transmission case 37R is rotatably supported on the left and right of the crankcase 33. On the left side of the crankcase 33, the right power transmission case 37R is rotatably supported by a ball bearing 70 held by a support metal 69 attached to the left crankcase 33L by a bolt 68 (the enlarged view is shown in the figure). 4). The front half of the power transmission case 37 is covered with a front cover 46. The front cover 46 is fixed to the left power transmission case 37L by bolts (not shown).

  On the right side of the crankcase 33, the right power transmission case 37R can be pivoted to a support hardware 72 attached to the right crankcase cover 62 with bolts 71 via connection hardware 74A and 74B supported by a roller bearing 73. It is supported by. The right power transmission case 37R and the connecting hardware 74A, 74B are integrated with bolts 75A, 75B. Since the front end of the rear fork 76 that supports the rear axle 17 is attached to the connection hardware 74A, 74B via the bolt 75B, the rear fork 76 rotates together with the connection hardware 74A, 74B and the right power transmission case 37R.

  The internal space of the power transmission case 37 is divided into two by a gear case 37G. The transmission chamber 44 is on the left side and the gear chamber 45 is on the right side. A plurality of rotating shafts are incorporated in the power transmission case 37. From the front, the crankshaft and continuously variable transmission drive pulley shaft 15, the continuously variable transmission driven pulley shaft 38, the idle shaft 39, the clutch shaft 40, the gear reducer intermediate shaft 41, and the rear axle 17. A drive pulley 42 provided on the drive pulley shaft 15, a driven pulley 43 provided on the driven pulley shaft 38, and a starting clutch 90 provided on the clutch shaft 40 are provided in the transmission chamber 44. Gears provided on the driven pulley shaft 38, the idle shaft 39, the clutch shaft 40, the intermediate shaft 41, and the rear axle 17 and meshing with each other are provided in the gear chamber 45. A rear wheel 18 is attached to the rear axle 17. A gear reducer 31 is constituted by gears provided on the clutch shaft 40, the gear reducer intermediate shaft 41, and the rear axle 17.

  In the above configuration, the driving pulley 42, the driven pulley 43, and the starting clutch 90 are arranged in the front-rear direction of the power unit 1, so that the width in the left-right direction of the power unit 1 can be reduced, the power unit 1 can be downsized, , Can improve the degree of freedom of appearance design.

  Further, since the rotation surface of the V belt 79 wound around the pulleys 42 and 43 and the rotation surface of the start clutch 90 are arranged at the same position in the vehicle width direction, both the pulleys 42 and 43 and the start clutch The right side surface of 90, that is, the side surface on the rear wheel 18 side becomes flat, and the overhang to the rear wheel 18 side can be reduced.

  In the conventional technique, the drive pulley shaft 15 and the driven pulley shaft 38 are separated from each other, and the driven pulley shaft 38 is disposed behind the front end 18a of the rear wheel 18. However, in this embodiment, the driven pulley shaft 38 is Since it is disposed between the drive pulley shaft 15 and the front end 18a of the rear wheel 18, the power unit 1 can be reduced in size by bringing the pulley shafts 15 and 38 closer to each other.

  FIG. 4 is an enlarged plan view of the front half of the power transmission device 14 and mainly shows the V-belt type continuously variable transmission 30 in the transmission chamber 44. The drive pulley shaft 15 of the V-belt type continuously variable transmission 30 is the crankshaft 15 itself, and the drive pulley 42 of the V-belt type continuously variable transmission 30 is provided on the left extension portion of the crankshaft 15. The driven pulley shaft 38 of the V-belt type continuously variable transmission 30 is rotatably supported by a left power transmission case 37L, a gear case 37G, and a right power transmission case 37R via ball bearings 77A, 77B, and 77C. . An endless V-belt 79 is bridged between the driving pulley 42 and the driven pulley 43, and the rotation of the driving pulley 42 is transmitted to the driven pulley 43.

  The drive pulley 42 includes a drive pulley fixed half 42A, a drive pulley movable half 42B, a weight roller 42C, and a ramp plate 42D. The driven pulley 43 includes a driven pulley fixed half 43A, a driven pulley movable half 43B, and a coil spring 43C. Before the driven pulley 43 is attached to the driven pulley shaft 38, the driven pulley shaft 38 is supported by the ball bearing 77B of the gear case 37G and the ball bearing 77C of the right power transmission case 37R. As described above, the driven pulley shaft 38 and the like can be mounted in a state where the driven pulley shaft 38 is supported on the wall bodies on both sides of the gear chamber via ball bearings. improves.

  When the rotational speed of the crankshaft 15 increases, in the drive pulley 42, the weight roller 42C between the drive pulley movable half 42B and the ramp plate 42D moves outward by centrifugal force, and the drive pulley movable half 42B Is pushed, the distance between the two halves 42A, 42B of the drive pulley 42 is reduced, and the winding diameter of the V-belt 79 is increased. As a result, the tension of the V-belt 79 increases, so that on the driven pulley 43 side, the driven pulley movable half 43B moves against the biasing force of the coil spring 43C, and the distance between the two halves 43A and 43B increases. The winding diameter of 79 becomes smaller. As a result, the rotational speed of the driven pulley 43 increases in accordance with the dimensional ratio of the winding diameter of the V belt 79. In this way, a continuously variable transmission is automatically performed.

  FIG. 5 is an enlarged plan view of the rear half of the power transmission device 14. The power transmission case 37 is divided into left and right parts by a gear case 37G. FIG. 5 shows a rear portion of the transmission chamber 44 and a gear chamber 45. A starting clutch 90 is accommodated in the rear part of the transmission chamber 44. A gear reducer 31 composed of three rotating shafts is provided behind the driven pulley shaft 38. Between the driven pulley shaft 38 and the gear reducer 31, a power transmission unit 80 centering on an idle gear 82 that transmits the output of the driven pulley shaft 38 to the gear reducer 31 is provided.

  The driven pulley shaft 38 of the V-belt type continuously variable transmission 30 passes through the gear case 37G and is supported by the left power transmission case 37L, the gear case 37G, and the right power transmission case 37R via ball bearings 77A, 77B, and 77C. The driven pulley shaft gear 81 of the output gear of the continuously variable transmission 30 is formed integrally with a portion sandwiched between the gear case 37G and the right power transmission case 37R of the driven pulley shaft 38.

  Next to the driven pulley shaft 38, an idle shaft 39 is rotatably supported by a right power transmission case 37R and a gear case 37G via a ball bearing, and has a large diameter meshing with the driven pulley shaft gear 81. An idle gear 82 is integrally formed.

  Conventionally, a starting clutch is generally provided on the driven pulley shaft, and the driven pulley shaft is long. However, in the power unit 1, the driven pulley shaft 38 and the clutch shaft 40 are provided independently. Since it is shorter, the bank angle can be secured easily. The driven pulley shaft 38 is a short shaft structure close to the drive pulley shaft 15 and the driven pulley shaft 38 is located near the front end of the rear wheel 18, but the driven pulley shaft 38 is short, Interference between the pulley shaft 38 and the rear wheel 18 can be avoided. Further, since the driven pulley shaft 38 is short, the shaft distortion due to the tension of the V belt 79 can be reduced.

  The movable half 43B of the driven pulley 43 is disposed on the left side of the vehicle, that is, on the outer side in the left-right direction with respect to the center of the driven pulley 43. Since the position of the driven pulley shaft 38 is closer to the front than in the prior art, the movable half 43B portion having a large overhang in the driven pulley 43 is closer to the front of the power unit 1, so that the continuity by the vehicle body cover 25 is given. Design freedom is improved.

  In the above configuration, the power transmission unit 80 centered on the idle gear 82 for transmitting power from the driven pulley shaft 38 to the clutch shaft 40 is provided in an extension space that extends forward from the accommodation space of the gear reducer 31. Since the power unit 1 is downsized, the appearance is slim, and the power transmission unit 80 and the gear reducer 31 are shared by the same space, the structure is simplified.

  The driven pulley shaft gear 81, the idle gear 82, and the clutch shaft input gear 87 are arranged at the same position in the vehicle width direction, that is, on the same rotation surface. As a result, the width of the gear chamber 45 can be reduced, so that the left and right widths of the transmission chamber 44 can be relatively wide, and air circulation is improved. Improvements can be made.

  Next to the idle shaft 39, a clutch shaft 40 serving as an input shaft of the gear reducer 31 is provided. The clutch shaft 40 includes a clutch shaft inner shaft 40A and a clutch shaft outer shaft 40B. The clutch shaft inner shaft 40A is supported by a left power transmission case 37L and a right power transmission case 37R via ball bearings 83A and 83B. The clutch shaft outer shaft 40B is supported by the clutch shaft inner shaft 40 via a ball bearing 83C and a needle bearing 84, and is supported by a gear case 37G via a ball bearing 85. The structure that supports the clutch shaft inner shaft 40A at a wide interval and also supports the intermediate portion of the clutch shaft outer shaft 40B can stably support the rotating shaft and prevent the shaft from becoming large. it can.

  A clutch shaft input gear 87 having the same diameter as the driven pulley shaft gear 81 is integrally formed with the clutch shaft outer shaft 40B. The clutch shaft input gear 87 meshes with the idle gear 82 and rotates at the same speed as the driven pulley shaft gear 81. A clutch inner 88 is connected to the left end of the clutch shaft outer shaft 40B protruding toward the transmission chamber 44, and a clutch outer 89 is connected to the left end of the clutch shaft inner shaft 40A. It is configured in the chamber 44. When the rotational speed of the clutch shaft outer shaft 40B exceeds a predetermined rotational speed, the starting clutch 90 is connected by centrifugal force, and the clutch shaft inner shaft 40A starts rotating. A small-diameter clutch shaft output gear 91 is integrally formed at the right end portion of the clutch shaft inner shaft 40A.

  A clutch shaft input gear 87 that receives power from the driven pulley shaft 38 and a clutch shaft output gear 91 that outputs power from the clutch shaft 40 toward the rear axle 17 are provided on the clutch shaft 40 in an overlapping manner. The shafts for supporting both gears extend through the gear case 37G to the transmission chamber 44, and are provided with a clutch inner 88 on one shaft and a clutch outer 89 on the other shaft. The gear chamber 45 is a wet space filled with lubricating oil, and the transmission chamber 44 is a dry space. Since the starting clutch 90 is disposed in the dry transmission chamber, the gear chamber 45 can be downsized and the cooling structure of the starting clutch 90 can be simplified.

  A gear reducer intermediate shaft 41 is provided next to the clutch shaft 40, and an intermediate shaft large diameter gear 92 that meshes with the small diameter clutch shaft output gear 91 is fitted and adjacent to the right side of the intermediate shaft large diameter gear 92. Thus, the intermediate shaft small-diameter gear 93 is integrally formed with the gear reducer intermediate shaft 41.

  Next to the gear reducer intermediate shaft 41, a rear axle 17 is provided. The rear axle 17 is rotatably supported by a gear case 37G and a right power transmission case 37R via ball bearings 95A and 95B, and a right end protruding outward is provided with a ball bearing 95C on the rear fork 76. It is rotatably supported via (FIG. 3). A rear axle large diameter gear 94 that meshes with the intermediate shaft small diameter gear 93 is fitted to the rear axle 17. With the above configuration, the torque of the driven pulley shaft 38 is decelerated via the gear reducer 31 and transmitted to the rear axle 17, and the rear wheel 18 (FIG. 3) is rotationally driven together with the rear axle 17.

  In the gear reducer 31, the speed is reduced through meshing of a plurality of gears from the small diameter clutch shaft output gear 91 to the rear axle large diameter gear 94 and is input to the rear wheel 18. The gears of the gear reducer 31 are meshed so as to be sequentially inward in the vehicle width direction, and a gentle bend in the width direction of the power transmission case 37 is ensured. The stress can be reduced.

  FIG. 6 is a cross-sectional view of the rear part of the power transmission case 37 as viewed from the left. A gear chamber peripheral wall 100 that forms the periphery of the gear chamber 45 is erected on the inner side of the right power transmission case 37R. A large number of screw holes 101 are provided around the peripheral wall 100 of the gear chamber, and a gear case 37G is attached thereto. The gear case 37G is not flat, but has a peripheral wall having an edge that abuts against the peripheral wall 100 of the gear chamber (FIG. 5). A gear chamber 45 is formed by the gear case 37G, the gear chamber peripheral wall 100, and the wall surface of the right power transmission case 37R. The gear chamber 45 is a wet space into which lubricating oil is injected. On the other hand, the space outside the gear chamber 45 divided by the gear case 37G is a transmission chamber 44 in which the V-belt type continuously variable transmission 30 and the starting clutch 90 are accommodated. In the V-belt type continuously variable transmission 30, the transmission chamber 44 becomes a dry space because it does not function when the belt contact portion slips.

  The gear chamber 45 is provided with an extension of the driven pulley shaft 38, an idle shaft 39, a gear holding portion of the clutch shaft 40, an intermediate shaft 41, and the rear axle 17, and a gear is provided on each shaft. In the figure, the driven pulley 43 and the starting clutch 90 of the transmission chamber 44 are also shown by phantom lines. The rotation direction of each gear, the driven pulley 43, and the starting clutch 90 is indicated by an arrow W.

  The labyrinth structure of the breather 102 that performs breathing in the gear chamber 45 is provided above the driven pulley shaft gear 81 and the idle gear 82 in the gear chamber 45, and the oil mist flowing from the breather inlet 102a is separated into gas and liquid. . The arrow M and the arrow described in the maze structure indicate the direction of the oil mist flow.

  The gas component is discharged from the upper gas discharge hole 103 and sent to the air cleaner 19 (FIG. 1). The liquid oil adhering to the wall of the breather 102 returns into the gear chamber 45 from the liquid discharge hole 104 below the breather 102. The breather 102 at this position can sufficiently secure the distance from each gear in the gear chamber 45 to the breather inlet 102a, so that intrusion of oil mist can be reduced and the breather performance can be improved.

  An oil reservoir 105 is provided on the lower wall 100b of the gear chamber 45 that accommodates the idle gear 82. The oil sump portion 105 has a depth at which the tooth tip of the idle gear 82 is immersed, and the lubricating oil can be lifted by the tooth tip of the idle gear 82 and supplied to the meshing portions of the front and rear gears. Lubricating oil can also be supplied to the lubricating portion of the driven pulley shaft 38 that is remote from the gear reducer 31.

  Both the upper wall 100a and the lower wall 100b of the gear chamber peripheral wall 100 are long in the front-rear direction inclined forward. Therefore, the lubricating oil adhering to the upper and lower walls 100a and 100b as a splash in the gear chamber 45 flows rearward along the upper and lower walls 100a and 100b and falls to the rear oil reservoir 106. Utilizing the slopes of the upper and lower walls 100a and 100b of the gear chamber 45, the return of the lubricating oil is improved, and while the lubricating oil returns, it returns while reducing the friction of the rotating part, so the drain return structure is simplified and maintainability Has improved. The lubricating oil that has returned to the rear oil sump 106 is lifted up by the intermediate shaft large-diameter gear 92 and used again for gear lubrication.

  The power transmission device 14 introduces outside air from the air intake 98 on the front side of the power transmission case 37 by the blades 97 of the driving pulley fixing half 42A (FIGS. 3 and 4), and V-belt type continuously variable transmission. A cooling mechanism for cooling the machine 30 and the starting clutch 90 is provided. In the transmission chamber 44, the driving pulley 42, the driven pulley 43, and the starting clutch 90 are rotating. These rotating bodies rotate in the same direction and act to push the air in the lower half of the transmission chamber 44 backward. The air flow in the transmission chamber 44 is indicated by the arrow A in FIG. Since the gear is in the gear chamber 45, it is not related to the flow of air. The driving pulley 42, the driven pulley 43, and the starting clutch 90 are cooled by this air flow. The cooling fins 99 are provided on both halves 43A and 43B of the driven pulley 43, and the cooling fins 96 are also provided on the clutch outer 89 of the starting clutch 90 (FIG. 5). . The air that has reached the end is exhausted from the exhaust hole 107 at the rear of the transmission chamber 44, but a part of the air moves from the upper part of the transmission chamber 44 to the front of the transmission chamber 44 as the start clutch 90 rotates. Taken back to cool each device.

  Since the drive pulley 42, the driven pulley 43, and the starting clutch 90 rotate in the same direction, and the rotation surfaces thereof are substantially on the same plane, the transmission chamber 44 has almost no unevenness in its plan view, and the driven pulley Since the dimension of the shaft 38 is also shortened, the flow of internal cooling air becomes smooth, the cooling performance of the rear start clutch 90 is improved, and the durability of the power transmission device 14 can be improved.

  FIG. 7 is an enlarged plan view according to another embodiment of the latter half of the power transmission device 14. This embodiment is different from the embodiment of FIG. 5 in that a left power transmission case side partition wall 108 and a gear case side partition wall 109 are provided and their edges are brought into contact with each other. The transmission chamber 44 shown in FIG. 5 is separated into a pulley chamber 44A and a clutch chamber 44B. A sealing material 110 is provided at the contact portion between the partition walls 108 and 109 to prevent leakage of gas or liquid. Portions other than those described above are the same as those shown in FIG.

  In the above configuration, the pulley chamber 44A is a dry space, and the clutch chamber 44B is a wet space. The driving pulley 42, the driven pulley 43, and the V belt 79 are cooled by outside air introduced from the air intake port 98. The starting clutch 90 is lubricated by lubricating oil supplied from the gear chamber 45 through a supply hole (not shown). In this embodiment, since the pulley chamber 44A is downsized, the cooling air is prevented from staying, so that the cooling performance is improved and the start clutch 90 is lubricated with the lubricating oil supplied from the gear chamber 45. The lubricity of the clutch 90 is improved.

As described in detail above, the following effects are brought about in the above embodiment.
(1) The power unit 1 and the gear reducer 31 can be placed in the same space and the lubrication structure can be shared and simplified while downsizing the power unit 1 and making the appearance slim.
(2) The gear chamber 45 is a wet space into which lubricating oil is injected, and the transmission chamber 44 is a dry dry space. The start clutch 90 can be disposed in a dry transmission chamber without making it wet, and the gear chamber 45 can be downsized and the cooling structure of the clutch 90 can be simplified.
(3) The structure that supports the inner shaft 40A of the clutch shaft 40 at a wide interval and also supports the intermediate portion of the outer shaft 40B, so that the rotating shaft can be supported stably and the enlargement of the shaft is prevented. can do.
(4) Since the distance from each gear of the gear reducer 31 to the breather inlet 102a can be sufficiently secured, the intrusion of oil mist or the like can be reduced, and the performance of the breather 102 can be improved.
(5) Lubricating oil can be swept up and supplied to the lubricating portion of the driven pulley shaft 38 far from the gear reducer 31 by the tooth tip of the idle gear 82.
(6) Since the return of the lubricating oil is improved by utilizing the inclination of the upper and lower walls 100a and 100b of the gear chamber 45, the drain is returned while reducing the friction of the rotating portion while the lubricating oil is returning. Maintenance can be improved by simplifying the structure. The lubricating oil that has returned to the oil sump portion 106 at the rear is scraped up by the intermediate shaft large-diameter gear 92 and is used for lubrication again.
(7) Since the driven pulley shaft 38 is supported by the gear case 37G and the right power transmission case 37R via the ball bearings 77B and 77C, the operation of attaching the driven pulley 43 and the like is easy and the assembly is easy. improves.
(8) In another embodiment in which the pulley chamber 44A and the clutch chamber 44B are partitioned, the pulley chamber 44A is reduced in size, so that the cooling performance is improved and the start clutch 90 is lubricated with the lubricating oil supplied from the gear chamber 45. Therefore, the lubricity of the starting clutch 90 is improved.

  DESCRIPTION OF SYMBOLS 1 ... Power unit, 13 ... Internal combustion engine, 14 ... Power transmission device, 15 ... Crankshaft / drive pulley shaft, 17 ... Rear axle, 18 ... Rear wheel, 30 ... V belt type continuously variable transmission, 31 ... Gear reducer, 37 ... Power transmission case, 37L ... Left power transmission case, 37G ... Gear case, 37R ... Right power transmission case, 38 ... Driving pulley shaft, 40 ... Clutch shaft, 40A ... Clutch shaft inner shaft, 40B ... Clutch shaft outer shaft, 44 ... Transmission chamber, 45 ... Gear chamber, 79 ... V belt, 80 ... Power transmission part, 81 ... Driven pulley shaft gear, 82 ... Idle gear, 87 ... Clutch shaft input gear, 88 ... Clutch inner, 89 ... Clutch outer , 90 ... Starting clutch, 91 ... Clutch shaft output gear, 100 ... Gear chamber peripheral wall, 100a ... Gear chamber upper wall, 100b ... Gear chamber lower wall, 102 ... Breather, 102a ... Breather inlet, 105 ... Oil reservoir, 106 ... Oil sump, 108 ... Left power transmission case side partition, 109 ... Gear case side partition, 110 ... Sea A: Cooling air flow direction, M: Oil mist flow direction, W: Rotating body rotation direction

Claims (8)

In a vehicle power unit in which an internal combustion engine and a power transmission device thereof are integrated, and a rear wheel as a drive wheel is swingably supported with respect to a vehicle body,
The power transmission device includes a V-belt continuously variable transmission, a gear reducer connected to a rear axle, and a clutch shaft serving as an input shaft of the gear reducer, and a driven pulley shaft of the V-belt continuously variable transmission. Is a separate shaft from the clutch shaft, the driven pulley shaft is provided close to the drive pulley shaft, and the power transmission portion from the driven pulley shaft to the clutch shaft is disposed in the front extending portion of the space for housing the gear reducer. A vehicle power unit characterized by that.   The power transmission case that accommodates the power transmission device is divided by a gear case, and is divided into a transmission chamber that accommodates a V-belt type continuously variable transmission and a gear chamber that accommodates a gear reducer, and the driven pulley shaft A clutch shaft input gear that receives power from the clutch shaft and a clutch shaft output gear that outputs power from the clutch shaft toward the rear axle are provided on the clutch shaft. 2. The vehicle according to claim 1, wherein a starting clutch is formed by extending through the gear case and extending into the transmission chamber, and supporting a clutch inner on one shaft and a clutch outer on the other shaft. Power unit.   The clutch shaft that penetrates the gear case and extends to the transmission chamber has an inner shaft supported at both ends by the outer wall body of the gear chamber of the power transmission case and the outer wall body of the transmission chamber of the power transmission case, 2. The vehicle power unit according to claim 1, comprising an outer shaft supported on the inner shaft, and the outer shaft being supported by the gear case at an intermediate portion thereof.   2. A maze structure of a breather for performing breathing in the gear chamber is provided on an upper portion of a portion of the gear chamber that houses a gear for transmitting power from a driven pulley shaft gear to a clutch shaft input gear. The vehicle power unit described in 1.   Power transmission between the driven pulley shaft gear and the clutch shaft gear is transmitted through an idle gear, and an oil reservoir is provided on the lower wall of the gear chamber that houses the idle gear. The vehicle power unit according to claim 4.   5. The vehicle power unit according to claim 4, wherein the gear chamber has a long shape in the front-rear direction in which both upper and lower walls are inclined forward.   2. The vehicle power unit according to claim 1, wherein the driven pulley shaft is supported by wall bodies on both sides of the gear chamber via ball bearings.   3. A pulley chamber for housing the pulley and a clutch chamber for housing the starting clutch are separated by providing a partition, and the starting clutch is lubricated with a lubricating oil supplied from a gear chamber. The vehicle power unit according to claim 6.

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