JP2003307155A - Crank case and its lubricating structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crank case and its lubricating structure capable of securing a sufficient oil pressure for a lubricating oil without increasing the mechanical loss while the number of components remains a minimum, and of being achieved in a compacted construction. <P>SOLUTION: A bulkhead 66 is formed to partition the inside space 33 of a crank case 21 into a front and a rear compartment, and part of the bulkhead is formed so as to overlap on any object to be lubricated 47 installed in the front chamber 33 when viewed on the side elevation, and shafts 45 and 57 to bear objects to be lubricated are located close to each other so that the rotational track 47P of the object 47 in the front compartment 33 and the rotational track 19P of another object to be lubricated 19 installed in the first chamber 56 formed outside of the crank case will overlap, while an opening 67 to open according to the manufacturing method when the bulkhead is to be formed is blocked with a separately provided partitioning member 68 so as to make different the level of the lubricating oil in the inside space 33 of the crank case from the level of the lubricating oil in the first chamber 56 outside the crank case. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crankcase and its lubricating structure.

[0002]

2. Description of the Related Art Since a power system such as an engine and a transmission mechanism has many sliding parts and rotating parts, a lubricating device is used to supply lubricating oil to each part, and the lubricating oil works to increase the frictional resistance of each part. It is designed to be reduced and the engine functions to the fullest.

A general lubricating structure of a lubrication device for a four-cycle engine is, for example, an oil pan (wet sump) provided integrally or separately under the crankcase of the engine or an oil tank provided separately from the engine. Lubricating oil stored in the (dry sump) is sucked up by an oil pump and pressure-fed to each lubrication part in the engine (forced lubrication), for example, a part of crankshaft, transmission gear, clutch mechanism is lubrication oil in an oil pan. There is a method in which the lubricating oil is agitated by the rotation of the crankshaft, the transmission gear, and the clutch mechanism to be scattered in the crankcase or the mission chamber (natural lubrication).

By the way, a power system installed in a scooter type vehicle is installed in a driving seat or under the floor of a vehicle body cover. Therefore, the power system is required to have a shape that suppresses the total height. Therefore, the shafts provided in the power system are arranged substantially horizontally and in parallel, and as a result, the shape of the power system is long in the front-rear direction.

If the shape of the power system is long in the front and rear,
Lubricating oil in the oil pan provided on the crankcase moves greatly in the front-rear direction as the vehicle accelerates and decelerates, making it difficult to secure a reliable hydraulic pressure. .

In order to solve this problem, therefore, a power system in which the shape of the power system is elongated in the front-rear direction has a crankcase in the front-rear direction in the crank chamber in which the crankshaft is housed and in the mission chamber in which the mission mechanism mechanism is housed. To reduce the front and rear length of the oil pan, and forcibly lubricate the crankcase.
The mission room had a lubrication structure such as natural lubrication.

[0007]

However, in order to separate the crankcase into the front and rear, it is necessary to provide a partition wall in the crankcase, which further lengthens the shape of the power system and causes an increase in the size of the vehicle body. I will end up.

On the other hand, the wet sump type lubrication structure has a simple structure and requires a small number of parts. On the other hand, in order to reliably secure the hydraulic pressure, it is necessary to secure a certain level or more for the lubricating oil suction port and the oil level height. On the contrary, if the oil level is too high, for example, the resistance increases when the lubricating oil is agitated by the rotation of the clutch mechanism, which causes a problem that the clutch is dragged (mechanical loss) at the time of engine start and the startability is deteriorated. Therefore, in the wet sump type lubrication structure, it is necessary to secure a certain vertical dimension of the crankcase and it is difficult to reduce the engine height.

On the other hand, since the dry sump type lubricating structure can reliably secure the lubricating oil under any condition, the crankcase can be packed particularly in the vertical direction and the engine height can be easily lowered. On the other hand, as described above, the oil tank is required separately, which greatly restricts the layout of the vehicle.

Further, in the case of a dry sump type lubrication structure,
It requires two oil pumps, a main pump for oil supply and a scavenging pump for oil recovery.
When both oil pumps are laid out coaxially, the lubricating oil may flow back into the crankcase through the scavenge pump, so a backflow prevention mechanism such as a backflow prevention valve is required. In addition, many parts are required for defoaming the lubricating oil containing air in the oil tank. Therefore, in the dry sump type lubrication structure, the number of parts and the cost increase, and the weight also increases.

The present invention has been made in consideration of the above-mentioned circumstances, and it is possible to secure a sufficient oil pressure of the lubricating oil with a minimum number of parts and to increase the mechanical loss, and to make the apparatus compact. It is an object of the present invention to provide a crankcase and a lubricating structure thereof.

[0012]

In order to solve the above-mentioned problems, the crankcase and the lubricating structure thereof according to the present invention have chambers inside and outside with an outer wall interposed therebetween, as set forth in claim 1. In a crankcase in which a plurality of objects to be lubricated and a plurality of shafts for supporting them are housed in the chamber, partition walls are formed to partition the chamber in the crankcase back and forth, for example, into a crank chamber and a mission chamber. , A rotation path of the primary driven gear disposed in the crank chamber and formed outside the crankcase by forming a part of the partition wall so as to overlap with the lubrication target disposed in the crank chamber, for example, a primary driven gear. The first chamber formed in, for example, the other lubrication target placed in the clutch chamber, for example, the rotation path of the clutch mechanism, should be overlapped. While the shafts that support the object to be lubricated are arranged in proximity to each other, the oil level of the lubricating oil accumulated in the crank chamber and the clutch chamber by closing the opening that is opened by the manufacturing method when the partition wall is formed by a separate partition member. Can be made different.

In order to solve the above-mentioned problems, as described in claim 2, a first oil pump for lubricating the lubricated object housed inside and outside the crankcase is provided, and the clutch chamber is provided. A second oil pump for collecting the lubricating oil accumulated in the crankcase, and the lubricating oil discharged by the second oil pump is returned to the lubricating oil stored in the crank chamber in the crankcase. The pump is arranged above the oil level of the lubricating oil stored in the crank chamber in the crankcase.

Further, in order to solve the above-mentioned problems,
As described in claim 3, a second chamber, for example, a magneto chamber is formed outside the crankcase with the outer wall sandwiched therebetween, and the discharge port of the second oil pump is opened to face the magneto chamber, and the magneto chamber is opened. The chamber and the crank chamber are communicated with each other below the oil level of the lubricating oil stored in the crank chamber.

Furthermore, in order to solve the above-mentioned problems, as described in claim 4, the second oil pump is housed in the crank chamber.

In order to solve the above problems,
As described in claim 5, the second oil pump is provided at a rear end of a wall portion forming the magneto chamber so as to straddle the wall portion from the back side, and the second oil pump discharge port is provided in the magneto chamber. A guide rib for guiding the lubricating oil flowing out from the downward direction is provided.

Further, in order to solve the above-mentioned problems, as described in claim 6, a rib is formed on the bottom surface of the clutch chamber to form an oil reservoir capable of temporarily storing lubricating oil, and Notches are provided in a part of the ribs so that the lubricating oil in the oil reservoir can be easily discharged.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a left side view showing an example of a scooter type motorcycle to which the present invention is applied. As shown in FIG. 1, the motorcycle 1 has a vehicle body frame 2, and a head pipe 3 is provided at the front end of the vehicle body frame 2. The head pipe 3 is provided with a front fork 5, a handlebar 6, etc. that rotatably support the front wheels 4, and the handlebars 6 steer the front wheels 4 rotatably left and right.

A power unit 7 is mounted on the lower center of the body frame 2. A transmission unit 8 is arranged at the rear of the power unit 7, and a front portion of the transmission unit 8 is pivotally attached to the rear of the power unit 7. The transmission unit 8 also functions as a swing arm type rear wheel suspension device, and is elastically and swingably supported by the vehicle body by a shock absorber 9. Then, the rear wheel 10, which is a driving wheel, is held at the rear end of the transmission unit 8.

An article storage chamber 11 which is a storage container for a helmet, luggage, tools and the like (not shown) is provided above the rear wheel 10. Further, above the article storage chamber 11, a driver's seat 12 for seating an occupant, which doubles as a lid of the article storage chamber 11, is openably and closably installed. Further, a fuel tank 13 is arranged between the lower front portion of the operation seat 12 and the upper rear portion of the power unit 7. The body frame 2 is covered with a body cover 14, which is a synthetic resin molded product, for example.

The vehicle body frame 2 and the vehicle body cover 14 between the head pipe 3 and the front portion of the driver's seat 12 are curved downward in a large U-shape to form a foot passing space extending in the width direction of the vehicle body, and the bottom portion thereof is formed. A footrest floor 15 for a rider, which is a low floor on which the driver puts his / her feet, is located between the upper frame 2a and the lower frame 2b of the vehicle body frame 2, is formed on the left and right of the vehicle. Further, behind the left and right rider footrest floors 15 are formed pillion rider footrest floors 16 on which passengers put their feet.
Further, a tunnel-shaped portion 17 is formed at the center of the rider footrest floor 15 so as to extend in the front-rear direction and project upward.

FIG. 2 is an enlarged left side view of the power unit 7 and the transmission unit 8. Further, FIG. 3 shows II of FIG.
It is sectional drawing which follows the I-III line. Furthermore, FIG.
It is the figure which expanded the power unit 7 part of. As shown in FIGS. 2 to 4, the power unit 7 includes an engine 18, which is a power generation unit, a clutch mechanism 19, and a mission mechanism 20.
And a transmission case 23 in which a V-belt type automatic transmission 22 is installed. The engine 18 is mainly composed of a front portion of the crankcase 21 and a cylinder assembly 24 arranged substantially horizontally in the front portion of the crankcase 21, and the crankcase 21 is provided with a plurality of engine mounting portions 25. It is fixed to the body frame 2.

The engine 18 mounted on the motorcycle 1 is water-cooled, and a radiator 26 for cooling engine cooling water is arranged in the vehicle body cover 14 between the front wheel 4 and the engine 18. It

An intake pipe (not shown) is connected to the upper portion of the cylinder head 27 provided on the front side of the cylinder assembly 24. On the other hand, the base end of the exhaust pipe 28 is connected to the lower portion of the cylinder head 27. The exhaust pipe 28 is guided to the lower portion of the power unit 7 and extends rearward, and the muffler 29 is connected to the downstream end thereof. In the present embodiment, the muffler 29 is arranged on the right side in the traveling direction of the vehicle body.

The engine 18 used in this embodiment is a so-called parallel two engine in which two cylinders (not shown) sharing a crankshaft 30 extending in the vehicle width direction inside a crankcase 21 are arranged side by side. It is a cylinder engine.

The crankcase 21 is molded by, for example, a die-casting method, and as shown in FIGS. 3 and 4, is provided with a mating surface 32 which extends in the front-rear direction and is parallel to the traveling direction axis 31 of the vehicle. It can be divided into. In addition, the crankcase 21 includes a front crankcase 21A and a middle crankcase 21 from the front to the rear.
B and the rear crankcase 21C are divided into three parts.

A crank chamber 33, which is a chamber inside the crankcase 21, is formed inside the front crankcase 21A, and the above-mentioned crankshaft 30 is disposed in the crank chamber 33 with both ends thereof being pivotally supported. . An annular wall portion 34 is formed on the opposite side of the crank chamber 33 with the outer wall of the left crankcase 21L interposed therebetween, that is, on the front outer side of the left crankcase 21L, and extends outward in the vehicle width direction. The formed opening is covered with the alternator cover 35 to form a magneto chamber 36 as a second chamber outside the crankcase 21 therein. The left end of the crankshaft 30 projects into the magneto chamber 36, and an alternator 99 (power generator) is attached to the projecting end.

A primary drive gear 37 is provided on one side of the crankshaft 30 in the crank chamber 33, that is, on the left side in this embodiment. Further, a starter driven gear 38 and a starter clutch 39 are arranged on the other side of the crankshaft 30, and the starter driven gear 38 is arranged in front of and above the crankcase 21 (FIG. 2).
See) Starter motor 40 and starter idle gear 41
Operatively connected via.

Further, a balancer shaft 42 constituting a balancer device is arranged above and below the crankshaft 30 in parallel with the crankshaft 30,
Primary drive gear 37 and starter driven gear 3
8 and a balancer drive gear 43 provided on the balancer shaft 42.
4 by operatively connecting the balancer shaft 42
Is driven to rotate. Although the lower balancer device is not shown, it basically has the same structure as the upper balancer device.

The left rear portion of the front crankcase 21A located behind the primary drive gear 37 is extended rearward to form the crank chamber 33 in a substantially L shape in plan view, and the inside of the extended portion 21a. A counter shaft 45, which is a shaft that axially supports the object to be lubricated and is arranged in parallel with the crankshaft 30, is axially supported.

The counter shaft 45 is provided with a primary driven gear 47, which is an object to be lubricated, through a known primary damper 46, which is a shock absorber, to form a primary reduction gear, and the primary driven gear 47 is provided on the crankshaft 30. The rotation of the crankshaft 30 is transmitted to the countershaft 45 by being operatively connected to the primary drive gear 37.

Extension portion 21a of front crankcase 21A
Further, a transmission case 23 is arranged on the right side of the middle crankcase 21B located behind it, and a V-belt type automatic transmission 22 is arranged inside thereof. The transmission 22 has a drive shaft 49 having a drive pulley 48 and a driven shaft 51 having a driven pulley 50. The drive shaft 49 is located behind the crankshaft 30 and in the width direction of the counter shaft 45 and the vehicle body. The counter shaft 45 is disposed coaxially with the counter shaft 45, and the driven shaft 51 is disposed in parallel with the drive shaft 49 behind the drive shaft 49.

The end portion of the drive shaft 49 facing the counter shaft 45, which is the left end portion in this embodiment, is splined to the counter shaft 45, for example.
A V-belt 52 is stretched between the drive pulley 48 and the driven pulley 50, and the rotational driving force of the engine 18 is transmitted from the driven pulley 50 to the driven shaft 51 via the V-belt 52. Then, the left end of the driven shaft 51 projects toward the inside of the middle crankcase 21B.

The middle crankcase 21B and the rear crankcase 21C arranged behind it have a mission chamber 53 (a front mission chamber 53A in the middle crankcase 21B and a rear mission chamber 53B in the rear crankcase 21C) therein. Prepare In addition, the front mission chamber 53A is sandwiched by the outer wall of the left crankcase 21L.
On the opposite side of the left crankcase 21L, that is, on the outer side of the middle of the left crankcase 21L, an annular wall portion 54 is formed toward the outer side in the width direction of the vehicle. A clutch chamber 56, which is the first chamber outside the crankcase 21, is formed therein.

The left end of the driven shaft 51 extends in the front mission chamber 53A toward the clutch chamber 56, and the projecting end of the driven shaft 51 is an inner clutch shaft which is a shaft for coaxially supporting the object to be lubricated. A wet multi-plate centrifugal clutch mechanism 19, which is an object to be lubricated, is attached via 57A and the outer clutch shaft 57B.

A secondary output shaft 58 is provided in the rear mission chamber 53B inside the rear crankcase 21C.
The secondary output shaft 58 is arranged in parallel with the driven shaft 51, and both the shafts 51, 58 are an output gear 59 provided on the outer clutch shaft 57B, a plurality of (two in this embodiment, front and rear) reduction gears 60a, It is connected via a fixed ratio reduction gear train 60 (located in front mission chamber 53A and rear mission chamber 53B) with 60b and an input gear 61 of secondary output shaft 58. Then, the rotational driving force of the engine 18, which is speed-changed by the speed change device 22 and interrupted by the clutch mechanism 19, is transmitted to the secondary output shaft 58. The input gear 61 is attached to the secondary output shaft 58 via a shock absorber, for example, a known mechanical damper 62.

The rotational driving force of the engine 18 transmitted to the secondary output shaft 58 is accommodated in the transmission unit 8 and a plurality of transmission gears 6 constituting a constant speed gear train 63.
It is transmitted to the axle shaft 65 of the rear wheel 10 via 4, 64 ...

FIG. 5 shows the crankcase 2 with the alternator cover 35 and the clutch cover 55 removed.
2 is a left side view of FIG. As shown in FIGS. 4 and 5, the crankcase 21 has a crank chamber 33 located in the front.
A partition wall 66 is provided for partitioning the rear mission chamber 53 and the rear mission chamber 53 (front mission chamber 53A and rear mission chamber 53B). The partition wall 66 is integrally formed inside the crankcase 21, and in the present embodiment, most of it is provided on the left crankcase 21L.

As shown in FIG. 4, the partition wall 66 extends in the plan view from the position immediately after the rotary orbit 47P of the primary driven gear 47 to the casting direction of the crankcase 21, that is, in the present embodiment, extends in the front-rear direction and extends in the vehicle traveling direction axis 31. After extending once in a direction orthogonal to the vehicle, that is, inward in the width direction of the vehicle, after extending forward, that is, in a direction orthogonal to the casting direction, in parallel with the side surface of the primary driven gear 47 and the axis 31 of the vehicle traveling direction. , Is again extended inward in the width direction of the vehicle.

That is, the mating surface 32 of the partition wall 66 provided on the left crankcase 21L with the right crankcase 21R is formed so as to overlap the primary driven gear 47 in a side view (see FIG. 5).

By the way, when a part of the partition wall 66 is formed in a direction perpendicular to the casting direction, it is necessary to use a mold (core) not shown, and an opening for removing the mold is required. . In the present embodiment, an opening 67 for removing the mold is formed on the wall surface of the left crankcase 21L facing the parallel portion of the partition wall 66 extending in parallel with the traveling direction axis 31 of the vehicle. The opening 67 is opened to face the clutch chamber 56. For example, the clutch chamber 56
It is closed from the side by a separate partition member 68.

The driven shaft 51, which constitutes the V-belt type automatic transmission 22 and has the clutch mechanism 19 at its end, has a rotational orbit 47P of the primary driven gear 47 when viewed axially as shown in FIG. The clutch mechanism 19 is arranged near the counter shaft 45 so as to overlap the rotation path 19P of the clutch mechanism 19 (see FIG. 5).

Since the power system such as the engine 18 and the mission mechanism 20 has many sliding parts and rotating parts, the lubricating device 6
Lubricating oil is supplied to each part using 9 or the like, and the function of the lubricating oil reduces the frictional resistance of each part so that the function of the engine 18 can be sufficiently exhibited. FIG. 6 is a system diagram showing the structure of the power system lubrication device 69 according to the present embodiment. In the following description, the positional relationship among the respective members is the position when the power unit 7 is mounted on the vehicle.

As shown in FIGS. 5 and 6, the engine 1
An oil pan 70 for storing lubricating oil is provided, for example, integrally with the crankcase 21 under the front crankcase 21A of FIG. Further, an oil reservoir 72 capable of storing lubricating oil is formed below the clutch chamber 56 by a rib 71 described later.

A first oil pump 73 for sucking up the lubricating oil in the oil pan 70 and pumping it to each lubricating portion in the engine 18 is provided, for example, in the lower front portion of the crankshaft 30. The first oil pump 73 is, for example, a well-known trochoid pump, and although not shown in detail, it is rotationally driven by a balancer shaft that constitutes the lower balancer device.

On the other hand, an oil pumping passage 74 is formed in the front crankcase 21A so as to extend from the oil pan 70 substantially forward and upward. A strainer 75 is provided at the upstream end of the oil pumping passage 74 and is always located in the lubricating oil in the oil pan 70. Further, the downstream end of the oil pumping passage 74 is connected to the first oil pump 73.
Is connected to the suction port 76.

On the other hand, a main gallery 77 is formed in the crankcase 21, and an oil supply passage 78 is branched from the downstream end of the main gallery 77 toward the sliding surface of the crankshaft 30 or a camshaft (not shown). It is formed.

A piston jet 79 for supplying lubricating oil is provided around the piston (not shown) in the front crankcase 21A.
Is connected to a jet passage 80 branched from the oil supply passage 78 (see FIG. 6).

Further, the upstream end of the main gallery 77 is opened to face the front lower part of the front crankcase 21A, and the outlet of an oil filter 81 for filtering impurities and the like in the lubricating oil is connected to this opening.

A sub gallery 83 extending from the discharge port 82 of the first oil pump 73 is connected to the inlet of the oil filter 81, and a relief passage 84 branches off from the middle of the sub gallery 83 to form an oil. Bread 70
Is provided toward the oil filter 8 by providing a relief valve 85 in the middle of the relief passage 84.
The hydraulic pressure (oil amount) in the sub gallery 83 upstream of 1 is controlled (see FIG. 6).

The lubricating oil that lubricates the sliding surfaces of the crankshaft 30 and the camshaft and the circumference of the piston is used as the internal space of the front crankcase 21A (crank chamber 33).
Is naturally dropped, or returned to the oil pan 70 via an oil drop passage (not shown) or the like.

On the other hand, an oil branch port 86 is formed at the downstream end of the main gallery 77, and an oil inlet 87 is formed at the front lower part of the wall portion 54 forming the clutch chamber 56. The branch port 86 is connected by the oil supply pipe 88, and the lubricating oil in the oil pan 70 is guided to the clutch chamber 56 by the first oil pump 73.

The lubricating oil introduced into the clutch chamber 56 is
For example, the oil passage 10 provided in the clutch cover 55
After being guided to the clutch mechanism 19 through 0 (see FIG. 2 and FIG. 4) and lubricating each part thereof, the internal space of the clutch chamber 56 is naturally dropped.

By the way, the clutch chamber 56 below the front reduction gear 60a disposed below the clutch shaft 57.
A rib 71 having a shape along the rotation orbit of the reduction gear 60a is integrally formed on the bottom surface of the wall portion 54 that forms the internal space of the clutch chamber 56 in an oil reservoir 72 formed by the rib 71. A part of the lubricating oil is temporarily stored (the rest falls to the bottom of the clutch chamber 56 and collects).

Then, the lubricating oil accumulated in the oil sump 72 is scattered into the clutch chamber 56 by the rotation of the reduction gear 60a and lubricates the reduction gears 60a and 60b and their surroundings. Further, an oil outlet 89 is formed in the lowest portion of the bottom surface of the wall portion 54, and a groove-shaped notch 90 is provided in a part of the rib 71, so that the lubricating oil accumulated in the oil sump 72 is discharged from the notch 90. It flows toward the oil outlet 89.

On the other hand, as shown in FIGS. 4 and 5, above the oil level 91 of the lubricating oil in the oil pan 70, inside the left crankcase 21L between the crankshaft 30 and the countershaft 45, and in the magneto chamber. Three
The second oil pump 92 is provided at the rear end of the wall portion 34 that forms 6
Is provided so as to straddle this wall portion 34 from the back side. The second oil pump 92 is also a known trochoid pump, for example, and is rotationally driven by a pump drive gear 93 provided on the counter shaft 45.

Further, the discharge port 94 of the second oil pump 92
Is opened on the wall surface of the left crankcase 21L near the rear end of the wall portion 34 of the magneto chamber 36 so as to face the interior of the magneto chamber 36, and the discharge port 94 is formed from the oil level 91 of the lubricating oil in the oil pan 70. It is located above.

Further, on the wall surface of the left crankcase 21L below the wall portion 34 of the magneto chamber 36, a communication hole 95 for communicating the interior of the magneto chamber 36 with the interior of the crank chamber 33 is provided below the oil level 91 of the lubricating oil in the oil pan 70. Is formed.

The suction port 96 of the second oil pump 92 and the oil outlet 89 on the bottom surface of the clutch chamber 56 are connected by an oil return pipe 97, and the clutch chamber 5
The lubricating oil accumulated in the bottom portion of 6 and the oil sump 72 is pumped up by the second oil pump 92, guided into the magneto chamber 36, and further returned from the communication hole 95 to the oil pan 70 in the crank chamber 33.

Further, at the discharge port 94 of the second oil pump 92, a guide rib 98 for guiding the lubricating oil flowing out from the discharge port 94 downward is provided from the upper side to the front side of the second oil pump 92 on the outer wall of the crankcase 21 and the inside of the alternator cover 35. (See FIG. 4).

Next, the operation of this embodiment will be described.

A partition wall 66 is formed in the crankcase 21 to partition the interior thereof into a front crank chamber 33 and a rear mission chamber 53 (a front mission chamber 53A and a rear mission chamber 53B), and a part of this partition 66 is formed. By forming the primary driven gear 47 arranged rearward (closer to the partition wall 66) in the crank chamber 33 so as to overlap with the primary driven gear 47 in a side view, the driven shaft 51 arranged forward (closer to the partition wall 66) in the mission chamber 53 is rotated. The rotation path 47P of the primary driven gear 47 and the clutch mechanism 1 when viewed from the direction.
It can be placed close to the counter shaft 45 so that the rotation orbit 19P of the crankshaft 9 overlaps with each other, and as a result, the crank chamber 33 and the mission chamber 53 can be separated without extending the front-rear length of the crankcase 21. 7 can be made compact.

Further, when the above-described partition wall 66 is formed by closing the opening 67 which is opened by the manufacturing method with a separate partition member 68, the oil level 91 of the lubricating oil accumulated inside and outside the crank chamber 33 can be made different.

Further, the oil pan 70 of the crank chamber 33 is used.
Oil pump 73 for supplying the lubricating oil stored in the crankshaft 30 and the camshaft (not shown)
Clutch mechanism 1 in clutch chamber 56, which is a separate chamber
By lubricating the lubricating oil 9 and the like, and then collecting the lubricating oil that has accumulated at the bottom of the clutch chamber 56 using the second oil pump 92 and returning it to the oil pan 70, the clutch mechanism 19 can be used. There is no problem that the resistance increases when the lubricating oil accumulated in 56 is agitated, and the clutch is dragged (mechanical loss) at the time of starting the engine 18 to deteriorate the startability.

As a result, it is possible to set an appropriate oil level 91 that can secure a reliable lubricating performance while suppressing the vertical dimension (height) of the crankcase 21.

The lubrication of the equipment in the clutch chamber 56 is based on the so-called dry sump system, but the oil pan 70 in the crank chamber 33 plays the role of a conventional oil tank. Therefore, the crankcase 21 can be reduced particularly in the vertical direction, and the height of the power unit 7 as a whole can be easily reduced.

On the other hand, the first oil pump 73 is a balancer shaft (not shown) constituting a lower balancer device (not shown), and the second oil pump 92 is a pump drive provided on the counter shaft 45. Gear 93
According to the above, the second oil pump 92 can be arranged extremely freely by rotatably driving the shafts separately. As a result, the oil level 91 of the lubricating oil stored in the oil pan 70 is set to the second oil pump 92.
Since it can be arranged on the upper side, the lubricating oil does not flow back from the second oil pump 92 into the crankcase 21 when the engine 18 is stopped, and a backflow prevention mechanism such as a backflow prevention valve is unnecessary.

Further, since the second oil pump 92 does not stir the lubricating oil, no mechanical loss occurs. Furthermore, since both pumps are driven to rotate by different shafts, the number of rotations can be set according to their respective functions, and the mechanical loss due to these oil pumps can be suppressed to the maximum.

Then, the second oil pump 92 is provided inside the left crankcase 21L and at the rear end of the wall portion 34 forming the magneto chamber 36 so as to straddle the wall portion 34 from the back side. The outlet 94 is connected to the oil pan 7
By opening the magnet chamber 36 facing the opening different from 0, the lubricating oil containing air can be easily and effectively defoamed without using a separate part, and the lubricating oil containing no air can be used as an oil. It is possible to return to the pan 70 and prevent a decrease in hydraulic pressure. Further, since the second oil pump 92 is housed in the crankcase 21, the space can be effectively used and noise can be reduced.

At the mounting position of the second oil pump 92 described above, the wall portion 34 and the guide rib 9 are provided on the opposite side (front side).
8 is present, the second oil pump 92 can be set at a position with high rigidity. Further, the guide rib 98 has a simple structure and can effectively prevent the lubricating oil flowing out from the discharge port 94 from scattering and guide the lubricating oil downward, so that the unnecessary lubricating oil adheres to the alternator 99. Can be prevented.

Furthermore, the clutch chamber 5 below the front reduction gear 60a, which is disposed below the clutch shaft 57.
A rib 71 having a shape along the rotation path of the reduction gear 60a is integrally formed on the bottom surface of the wall portion 54 forming the rib 7.
1 to the oil reservoir 72 formed by the clutch chamber 5
Since a part of the lubricating oil that has dropped in the internal space of 6 can be temporarily stored, the reduction gear 6 requiring lubrication
Lubricating oil can be supplied to 0a and 60b.

By providing, for example, a groove-shaped notch 90 in a part of the rib 71, the lubricating oil in the oil sump 72 can be easily discharged, and can be prevented from being stored more than necessary.

[0074]

As described above, according to the crankcase of the present invention, the front and rear chambers can be separated without extending the front-rear length of the crankcase, and the power unit can be made compact.

Further, according to the crankcase lubrication structure of the present invention, the lubricating oil does not flow back into the crankcase from the second oil pump when the engine is stopped.
Further, the lubricating oil containing air can be easily defoamed, and the lubricating oil containing no air can be returned to the oil pan.

Furthermore, the space can be effectively used,
Noise can be reduced, the second oil pump can be set at a position with high rigidity, and the lubricating oil flowing out from the discharge port of the second oil pump can be prevented from scattering with a simple structure.

Further, the lubricating oil can be supplied to the reduction gear or the like which requires lubrication of the clutch chamber, and the lubricating oil in the oil sump can be easily discharged so as not to be stored more than necessary.

[Brief description of drawings]

FIG. 1 is a left side view of a scooter type motorcycle showing an embodiment of a crankcase and a lubricating structure thereof according to the present invention.

FIG. 2 is an enlarged left side view of a power unit and a transmission unit.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is an enlarged view of a power unit portion of FIG.

FIG. 5 is a left side view of the crankcase with the alternator cover and the clutch cover removed.

FIG. 6 is a system diagram showing a structure of a power system lubricating device.

[Explanation of symbols]

1 Motorcycle 7 Power Unit 8 Transmission Unit 18 Engine 19 Clutch Mechanism (Lubrication Object) 19P Clutch Mechanism Rotation Orbit 21 Crankcase 22 V-belt Automatic Transmission 33 Crank Chamber (Crankcase Chamber) 34 Magnet Chamber (Crankcase Wall part forming outer second chamber 36 Magnet chamber (second chamber outside crankcase) 45 Counter shaft (shaft for supporting lubricated object) 47 Primary driven gear (lubricated object) 47P Rotational orbit of primary driven gear 56 Clutch Chamber (First Chamber Outside Crankcase) 57 Clutch Shaft (Shaft for Shaft Supporting Lubricated Object) 66 Partition 67 Opening Port 68 when Partition is Formed 68 Partition Member 69 Lubricating Device 70 Oil Pan 71 Forming Oil Sump Rib 72 Oil sump 73 First oil port Pump 90 Notch 91 Oil level of lubricating oil accumulated in oil pan 92 Second oil pump 94 Discharge port of second oil pump 98 Guide rib

Claims (6)

[Claims] 1. A crankcase having a chamber inside and outside with an outer wall sandwiched therein and housing a plurality of objects to be lubricated and a plurality of shafts for axially supporting them in the chamber, by forming a partition wall in the crankcase. The chamber is divided into front and rear, and a part of the partition wall is formed so as to overlap with the object to be lubricated arranged in the front chamber in a side view, and the object to be lubricated arranged in the front chamber is rotated. The shafts supporting the lubricated objects are arranged in proximity to each other so that the orbit and the rotational trajectory of the other lubricated objects arranged in the first chamber formed outside the crankcase overlap with each other. The clan is characterized in that the oil level of the lubricating oil accumulated in the chamber inside the crankcase and the first chamber outside the crankcase can be made different by closing the opening that opens due to the manufacturing method at the time of forming the Case. 2. A second oil that includes a first oil pump that lubricates the lubrication target housed inside and outside the crankcase, and that collects lubricating oil that collects in a first chamber formed outside the crankcase. The second oil pump is configured to return the lubricating oil discharged from the second oil pump to the lubricating oil stored in the crankcase chamber, while the second oil pump is stored in the crankcase chamber. The crankcase lubrication structure according to claim 1, wherein the lubrication structure is disposed above an oil level of the lubricating oil. 3. A second chamber is formed outside the crankcase with an outer wall interposed therebetween, and a discharge port of the second oil pump is opened so as to face the second chamber and the second chamber and the crankcase are inside. 3. The crankcase lubrication structure according to claim 2, wherein said chamber is communicated with the chamber below the oil level of the lubricating oil stored in the chamber in said crankcase. 4. The crankcase lubricating structure according to claim 2, wherein the second oil pump is housed in a chamber inside the crankcase. 5. The second oil pump is provided at a rear end of a wall portion forming the outer second chamber so as to straddle the wall portion from the back side, and the second oil pump is provided in the outer second chamber. The crankcase lubrication structure according to claim 3, further comprising a guide rib that guides the lubricating oil flowing out from the discharge port downward. 6. A rib is formed on the bottom surface of the first chamber formed outside the crankcase to form an oil reservoir capable of temporarily storing lubricating oil, and a notch is provided in a part of the rib to form an oil. The lubrication structure for a crankcase according to any one of claims 2 to 5, wherein the lubricating oil in the reservoir can be easily discharged.