JP3338205B2 - Vertical engine and outboard motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical engine having a crankshaft oriented vertically and an outboard motor equipped with such a vertical engine.

[0002]

2. Description of the Related Art Japanese Unexamined Utility Model Publication No. Hei 3-21509 and Japanese Unexamined Utility Model Publication No. Hei 3-23609 disclose a vertical engine (an upright engine) in which a crankshaft is directed in the vertical direction. A flywheel is provided at a lower end of the crankshaft protruding from the engine body.

[0003] The flywheel is housed in a flywheel chamber, and an oil for engine lubrication is housed in a transmission housing provided below and connected to the flywheel chamber. To prevent the oil from entering the flywheel chamber, the inside of the transmission housing and the inside of the engine body are communicated by a feed pipe and a return pipe arranged around the outside of the flywheel chamber, and the oil in the transmission housing is removed. The oil is fed to the oil pump in the upper part of the crank chamber through the feed pipe, and the return oil returns from the oil reservoir formed near the lower end of the crank cover to the inside of the transmission housing via the return pipe.

[0004]

In the above conventional vertical engine, oil in the engine body is returned to the transmission housing through a return pipe from an oil reservoir having only a flat bottom formed near the lower end of the trunk cover. There is a concern that the oil will not return smoothly.

Also, since the return pipe is connected at the lower end of the oil reservoir on the side opposite to the cylinder head and is connected directly to the transmission housing so as to bypass the flywheel chamber downward, the engine is mounted, for example. When the cylinder head side is lowered due to the inclination of the other side, the return of oil in the crank chamber becomes poor. In an outboard motor as an example of mounting a vertical engine,
This is, for example, during acceleration or when sailing without performing trim adjustment about the tilt axis.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and in the present invention, the crankshaft is directed vertically and the bottom wall of the crankcase of the crankshaft is provided. In a vertical engine in which a flywheel is provided at a lower end portion that penetrates and protrudes and an oil pan is provided at a position below the flywheel, an oil return passage that communicates the crank chamber and the oil pan is provided on a side of the flywheel. And the oil return passage is located below the flywheel and is connected to the oil pan in a vertical first passage portion, and the outer peripheral portion of the flywheel is directed toward the first passage portion. And a second passage portion extending downward and inclined.

According to the present invention, the oil in the crank chamber is returned to the oil pan through the oil return passage formed along the outer periphery of the flywheel, so that an external return connecting the crank chamber and the oil pan is provided. There is no need to provide pipes or the like, and the engine can be compacted.

The oil return passage extends from the crank chamber side of the outer periphery of the flywheel while being inclined downward, and reaches the second passage portion below the flywheel and above the oil pan. From the lower end position of the first oil passage to the oil pan in the vertical direction downward, so that the oil smoothly bypasses the flywheel from the upper crank chamber to the lower oil pan through the oil return passage. Even if the engine falls down, the return of oil does not deteriorate.

[0009]

An embodiment of an outboard motor to which the present invention is applied will be described below.

FIG. 1 is an overall side view of an outboard motor 1 equipped with a vertical engine according to the present invention. Reference numeral 1a denotes an outboard motor main body case including an extension case 2, a gear case 3, and the like, on which an engine 4 according to the present invention is mounted, and an upper portion of which is covered by an engine cover 5.

The outboard motor 1 is mounted on a stern 7 via a mounting device 6. The mounting device 6 includes a bracket 8 fixed to the stern 7 via bolts, and a swivel case 10 pivotally attached to the bracket 8 via a tilt shaft 9 mounted on the front end thereof so as to swing up and down. A swivel shaft 11 is pivotally supported by the swivel case 10 so as to be vertically rotatable. The outboard motor 1 is connected to the swivel shaft 11 by upper and lower connecting members.
They are connected via 12, 12a.

A crankshaft 13 of the engine 4 is oriented vertically, and a drive shaft 14 connected to the crankshaft 13 extends downward in the extension case 2 to reach the gear case 3. The lower end of the drive shaft 14 is connected to a propeller shaft 16 via a forward / reverse switching device 15 in the gear case 3, and the propeller 17 is transmitted via the crankshaft 13, the drive shaft 14, the forward / reverse switching device 15 and the propeller shaft 16. It is rotationally driven by engine power.

FIG. 2 is a longitudinal sectional view of the engine 4, and FIG. 3 is a schematic plan view showing the engine 4 in the engine cover 5 together with its accessories. As described above, the crankshaft 13 is vertically oriented. As shown in FIG. 1, the engine 4 is mounted with the crankshaft 13 positioned closer to the front (the boat side) of the outboard motor 1 and the cylinder head positioned closer to the rear. That is, in FIGS. 2 and 3, the right side corresponds to the front side of the outboard motor 1.

The main body of the engine 4 includes a cylinder block 18 integrally provided with a skirt portion 18a forming a half of a crankcase, a half crankcase 19 forming a remaining crankcase half, a cylinder head 20, and a cylinder. The head cover 21 is provided. The half-split crankcase 19 has the mating surface as the mating surface 18 of the skirt 18a.
c, and is integrally connected to the skirt portion 18a by the bolt 22.
23 are formed.

In the cylinder block 18, four cylinders are provided.
24 are arranged one above the other. That is, engine 4
Is an in-line four-cylinder four-stroke engine, in which each piston 25 is connected to a single vertically oriented crankshaft 13 via a connecting rod 26. The crankshaft 13 is provided on the cylinder block 18 side and the half-split crankcase 19 side, is fastened by bolts 27, and opposes bearing parts 28a,
It is rotatably supported in the crank chamber 23 by being sandwiched between 28b.

A camshaft 30 is disposed vertically in a valve operating chamber 29 formed in the cylinder head 20. This camshaft 30
Is the upper end 13 projecting from the crank chamber 23 of the crankshaft 13.
a driven pulley 31 mounted on the upper end of the cam shaft 30 protruding from the cylinder head 20.
And a belt 33 wound between the pulleys 31 and 32, and is driven by the crankshaft 13 via a winding transmission. On the upper end 13a of the crankshaft 13, a generator 36 is further mounted above the drive pulley 31.

The drive shaft 14 is connected to a lower end 13b of the crankshaft 13 which protrudes through the bottom wall of the crank chamber 23. A disk-shaped flywheel 34 is further connected to the lower end 13b by screws 35, and extends parallel to the lower surface of the engine body. By providing the flywheel at the lower end of the crankshaft and at the connection with the drive shaft, torsional vibration of the engine is reduced.

In FIG. 3, 37 is an intake valve, 38 is an exhaust valve,
Reference numerals 39, 39 denote rocker arms, and such a valve mechanism whose opening and closing are controlled by the cam shaft 30 is provided for each cylinder 24. Reference numeral 40 denotes an intake port provided in the cylinder head 20, and an intake pipe 41 connected to the intake port 40 extends forward along a side surface of the engine 4. 42 is a vaporizer, 42a
Is an intake silence box. Such an intake pipe 41 is used for each cylinder.
It is provided every 24, and is juxtaposed vertically along the side surface of the engine 4.

On the other side of the engine 4, an exhaust passage 43 extends in the vertical direction.
The exhaust port 44 corresponding to. The exhaust passage 43 is communicated with the upper end of an exhaust pipe (not shown) extending in the extension case 2 in the vertical direction. Exhaust gas is discharged from the lower end of the exhaust pipe into the water through a boss of a propeller through the exhaust pipe. .

On the same side as the exhaust passage 43 of the engine 4, an electric component box 45 containing electric components is provided in the front, and a starter motor 46 is provided below it. Reference numeral 45a denotes a spark plug cord which is connected to a spark plug on a side surface of the cylinder head 20. The output shaft 46a of the starter motor 46 protrudes downward and is gear-engaged with a ring gear 47 (FIG. 2) provided on the outer periphery of the flywheel 34.

FIG. 4 is a bottom view of the main block of the engine 4 composed of the cylinder block 18 and the half crankcase 19 connected thereto. As can be seen from FIG. 4 and FIGS. A lower portion of the block 18 is formed with a projecting portion 48a that extends laterally of the engine and the left and right sides of the outboard motor along the rotation plane of the cylinder head. In the outboard motor, a projecting portion 48b projecting forward is formed. These overhangs 48
a, 48b are respectively provided on the outer peripheral edges of the surrounding walls
a, 49b are provided. Enclosure walls 49a and 49b are mating surfaces
18c, they are joined together to form a dish-shaped portion that opens downward on the lower surface of the main blocks 18, 19 (the left and right surrounding walls 49a are close to the cylinder head, and are connected to each other rearward in the outboard motor). There).

On the lower surface of the cylinder block 18, the surrounding wall
An enclosing wall 50 is further provided on the inner side of 49a so as to be substantially concentric with respect to the bearing portion 28, and a semi-annular recess 51 which opens downward is formed between the enclosing wall 50 and the enclosing wall 49a. I have. The front end surface of the surrounding wall 50 forms a part of the mating surfaces 18c, are adapted to the end face of the branch portion 49b ₁ of the half crankcase 19 side enclosure 49b. Therefore, the recess 51 is closed at the front end.

FIG. 5 is an end view showing the end of the cylinder block 18 on the half crankcase 19 side. A packing surface 52 is provided on the end surface along the outer periphery from the skirt portion 18a to the lower overhang portion 48a. 22a is a bolt hole through which the bolt 22 passes. The end surface of the bottom wall 53 extending from the cylinder side and defining the lower part of the crank chamber 23 also forms a packing surface 54 together with the end surfaces of the surrounding walls 50 on both sides thereof. On the upper surface of the bottom wall 53, two left and right boss portions 55 are provided so as to protrude, and extend toward the rear cylinder portion. The end surfaces of the bosses 55 form part of the packing surface 54, and the bosses 55 are also provided with the same bolt holes 22a as described above.

A packing surface similar to the packing surfaces 52 and 54 is also provided on the half crankcase 19 side, and the bolts 22 are inserted into the bolt holes 22a by aligning these packing surfaces. The block 18 and the half crankcase 19 are integrally connected to form a crankcase.
Form 23. That is, the aforementioned mating surface 18c is formed by the packing surface 52 and the packing surface 54.

The crank bearing 28a is provided on the skirt 18
A is formed and supported on a bearing wall 56 protruding from the inner wall surface of the skirt portion 18a. However, the bearing 28a
Are substantially flush with the packing surface 52, but the end surface of the bearing wall 56 is drawn rearward from these surfaces, that is, toward the cylinder.

The bearing wall which corresponds to the bearing portion 28a ₁ of the lowermost
56 ₁ is formed integrally with the bottom wall 53,
The lower surface of the bearing portion 28a ₁ is located above the upper surface of the bottom wall 53,
Gap 57 is formed between the bearing portion 28a ₁ and the bottom wall 53. A relatively large-diameter semi-circular hole 58 is formed in this portion of the bottom wall 53, and the enlarged lower end portion 13 b of the crankshaft 13 penetrating through the bearing portion 28 a ₁ is formed through a seal piece 59. Fits in hole 58. Thus the gap 57 is shut off from the lower side of the bottom wall 53 by the crankshaft lower end portion 13b and the seal piece 59 oil-tightly and since the outer peripheral portion of the bearing portion 28a ₁ is connected to the bottom wall 53,
When the half crankcase 19 having the same structure is mounted with the crankshaft 13 interposed therebetween, the gap 57 becomes a closed space that is sealed from the surroundings. However by forming the recess slight on the end surface of the connection portion between the outer peripheral portion and the bottom wall 53 of the bearing portion 28a ₁ (mating surfaces of the half crankcase 19), the outer bottom wall a gap 57 in the left and right sides Communication hole 60 communicating with the top of 53
Is formed. Note bearing wall 56 ₁ is to continuously reinforce the wall in the side of the cylinder.

The flywheel 34 is attached to the lower end portion 13b of the crankshaft below the bottom wall 53 as described above. The flywheel 34 is covered by the bottom wall 53 and the upper wall of the protruding portion 48b on the half-split crankcase 19 side (see FIG. 2), and the periphery is surrounded by the surrounding wall 50 and the surrounding wall 49b connected thereto. In a downward recess. This recess forms the upper part of the flywheel chamber 61 (FIG. 2) which houses the flywheel. That is, the lower surface side of the bottom wall 53 corresponds to the ceiling of the flywheel chamber 61.

As shown in FIG. 2, a mounting case 62 is attached with bolts to the flat lower surfaces of the main blocks 18, 19 formed by surfaces connecting the lower end surfaces of the surrounding walls 49a, 49b, 50. The engine 4 is mounted on the extension case 2. As shown in FIG. 6, on the upper surface of the mount case 62, an enclosing wall 63a which abuts on the enclosing wall 50 and an enclosing wall 63b which abuts on the enclosing wall 49b are formed to project in a continuous annular shape. The recess containing the flywheel 34 on the main block side is closed from below by the enclosed portion to form a flywheel chamber 61.

Further, an enclosure 63c abutting on the enclosure 49a.
Is provided between the surrounding wall 63a and the surrounding wall 63c.
And a recess 51a is formed, which is connected to the opening 51 and closes the recess 51 from below (see FIG. 7).

As shown in FIG. 4, the output shaft of a starter motor 46 which projects into the flywheel chamber 61 from above and engages with the ring gear 47 of the flywheel 34 on one side of the surrounding walls 50 and 63a. In order to accommodate the 46a part, a recess 64
Is provided. In FIG. 6, 51b is a concave portion 51c which is cut off from the concave portion 51a by the concave portion 64.
The portion below the bottom wall portion 64 communicates with the recess 51a.

The mount case 62 is connected to a pair of left and right connecting members 12 via a mount rubber 65 extending in the left and right direction. The mount rubber 65 includes a core material 65a and a rubber 65b surrounding the core material 65a.
a. Rubber 65b is a holding member fastened to the bottom wall of flywheel chamber 61 by bolt 66
Pressed from above by 67.

An oil pan 68 is attached to a flat lower surface of the mount case 62 below the portion constituting the flywheel chamber 61 and rearward from the drive shaft 4 and hangs down. Has been placed. The inside of the mount case 62 is
A portion 62a constituting the portion 61 and a portion communicating with the oil pan 68
62b.

Oil suction pipe having a strainer 69 at the lower end
70 extends upward from the bottom of the oil pan 68 through the oil suction passage 71a of the mount case 62, and is connected to the oil suction passage 71 formed at the lower portion of the cylinder block 18. The oil suction passage 71 is provided at a lower end of the camshaft 30 and communicates with a suction port 73 of an oil pump 72 driven by the camshaft 30. The oil suction pipe 70 may be connected to the oil suction passage 71 of the cylinder block 18 through the oil communication portion 62b and an oil return port 84 described later.

As shown in FIGS. 1 and 3, the oil pressurized by the oil pump 72 passes through the oil supply passage 91a located below the lowermost cylinder from the pump outlet 72a to form the bottomed bottom of the mount case 62. Relay part 91b (see FIG. 6)
Sent to Up to this point, the lubrication route of the conventional vertical engine is almost the same. In the relay portion 91b, the oil supply path rises upward, communicates with an oil supply path 91c extending horizontally from the lowermost cylinder by one cylinder upward, and the oil passes through the oil supply path 91c to the front of the half crankcase 19, Further, it is sent to an oil filter 74 mounted above the mating surface 5a (FIG. 1) of the engine cover and the under case. Due to such an arrangement of the oil supply passage, even if there are a flywheel and a flywheel chamber below the crankcase and an oil return passage provided on the bottom wall of the crankcase, the cylinder head does not interfere with them. Oil can be sent from the side to the crankcase side. In addition, removal and replacement of the oil filter can be easily performed.

The oil that has exited the oil filter 74 flows into an oil passage 75 disposed vertically in the center of the front half of the half crankcase 19 in the left-right direction. Reach the bearings 28 to lubricate the bearings in these bearings. This oil further reaches the inside of the crankpin bearing 78 and the cylinder 24 through an oil passage 77 formed in the crankshaft 13, and lubricates the crankpin bearing 78 and the inner surface of the cylinder. Also, the crankshaft from above the oil passage 75
13. Passed above the cylinder block 18 through the oil passage 75a, is sent to the cylinder head 20 side to lubricate the camshaft 30.

The oil that has reached the inside of the cylinder 24 is
The cylinder wall portion 79 that defines the upper and lower cylinders 24 has a thickness equal to the thickness of the bearing portion 28a connected thereto. Since it is thinner than (width), a step a is generated in this portion, and the oil easily remains in the step a. Therefore, an oil hole 80 for connecting the upper and lower cylinders 24, 24 to this part
The remaining oil is dropped into the cylinder 24 below.

The oil hole 80 is provided in the skirt portion 18a of the cylinder block 18 in the open half-split crankcase.
By directing a drilling tool such as a drill obliquely upward from the mating surface side with 19, it is possible to easily drill without interfering with other parts. Therefore, the oil hole 80 is formed obliquely upward from the lower surface side of the cylinder wall portion 79 toward the rear.

Similar oil holes 80 are also provided between the lower cylinders 24, and the oil in each cylinder 24 sequentially flows downward through these oil holes 80 to reach the lowermost cylinder 24. . The lower cylinder 24 also has the oil hole
Although an oil drop hole 81 similar to 80 is provided, this oil drop hole 81 is, in a plane including the axis of the cylinder,
Drilled in the bearing wall 56 ₁ of the bearing portion 28a ₁ (FIG. 5), opens into the gap 57. The oil drop hole 81 can also be formed in the packing surface 54 without making a hole by directing a tool obliquely from the mating surface side with the half crankcase 19.

Since the lower portion of the gap 57 is closed by the lower end portion 13b of the crankshaft 13 whose diameter has been increased and the seal piece 59,
The oil that has flowed down to the gap 57 through the oil drop hole 81 does not flow into the flywheel chamber 61 that houses the lower flywheel 34, but passes through the communication holes 60 on the left and right and on the adjacent upper surface portion 53a of the bottom wall 53. Leaked to Lowermost bearing 28a ₁
From the oil seal 58 directly from the oil seal 58
Is returned through.

[0040] However, since the adjacent upper surface portion 53a is blocked to the outside by the boss portion 55, to guide the spilled oil here, through the bearing wall 56 ₁ and integrated therewith in the crank chamber wall portion An oil return passage 82 extending rearward, that is, toward the cylinder head. The oil return passage 82 reaches the upper position of the surrounding wall 50, that is, the outer peripheral portion of the flywheel chamber, as shown in FIG. Accordingly, the oil that has passed through the oil return passage 82 flows into the recess 51 formed outside the enclosure 50, and falls into the recess 51a of the mount case 62 that receives the recess 51 from below. .

[0041] Also in the outside of the boss portion 55, similar oil return passage 83 is provided through the bearing wall 56 _1, the recess 51a through the oil return passage 83 collects the return oil to the outside of the bottom wall 53 To be dropped.

As described above, the outside of the flywheel chamber 61 is positioned near the mating surface of the cylinder block 18 and the half crankcase 19 by the recess 51 on the cylinder block 18 side and the recess 51a on the mount case 62 side. An oil return passage that surrounds in a semi-circular shape is formed toward the rear. The bottom wall of the oil return passage, that is, the bottom wall 51b of the recess 51a is
As shown in FIGS. 2, 7 and 8, it is inclined downward toward the rear and has an oil return port at its lowest rear end.
84 (FIG. 6), and is open to the oil pan communication portion 62b of the mount case 62. Therefore, the oil that has fallen into the recess 51a via the oil return passages 82 and 83 is
The oil flows through the oil return port 84 to the oil return port 84 side, falls through the oil pan communication portion 62b from the oil return port 84, and is returned into the oil pan 68 below.

In other words, an oil return passage communicating the crank chamber 23 and the oil pan 68 is formed on the side of the flywheel 34, and the oil return passage is provided for the oil in the oil pan communication portion 62b to return to the oil return port 84b. A first vertical passage portion which is formed below the flywheel 34 and which communicates with the oil pan 68 and which is formed by a portion (a portion indicated by a phantom line 84a in FIG. 2) Place
A second passage portion, which is formed by 51 and 51a, extends downward while inclining the outer peripheral portion of the flywheel 34 toward the first passage portion 48a. The oil return passage is formed in a housing portion that covers the flywheel 34 and is formed by the surrounding walls 49, 50, 63 and the like.

Thus, the flywheel chamber 61 below the crank chamber 23 is located between the crank chamber 23 and the oil pan 68.
The oil return passage, which is detoured around the engine, is formed without increasing the size of the engine, and is conveniently mounted on the extension case 2 as shown in FIG. FIG.
In the figure, 89 is an undercase forming the lower part of the engine room, 90 is an undercover for covering the lower outer periphery thereof, and the undercase 89, the undercover 90 and the extension case 2 give the outboard motor body a gentle contour. ing. Further, the outlet of the oil return passage, that is, the oil return port 84 is provided at a position sufficiently lower than the bottom of the crank chamber 23 due to the inclination of the bottom wall 51b. To the crankcase
Even if the 23 side is lower than the cylinder head 20 side, the oil in the crank chamber 23 can be returned to the oil pan 68 without any trouble.

The oil lubricated around the cam shaft 30 reaches the oil return port 86 through the oil passage 85, and is returned to the oil return passage 86.
87, the oil is returned to the oil pan 68 via the oil return pipe 88.

[0046]

According to the present invention, in a vertical engine in which a crankshaft is directed substantially vertically and a flywheel is provided at a lower end protruding through a bottom wall of the crankcase of the crankshaft, a lower portion of the flywheel is provided. A passage for returning oil around the flywheel from the upper crankcase to the oil pan is formed inside the engine, and the entire engine can be made compact. Further, the oil can be smoothly returned from the crank chamber to the oil pan, and the oil return does not deteriorate even when the engine is tilted.

[Brief description of the drawings]

FIG. 1 is an overall side view of an outboard motor equipped with a vertical engine according to the present invention.

FIG. 2 is a vertical side view of the engine.

FIG. 3 is a schematic plan view showing an engine in an engine cover together with its accessories.

FIG. 4 is a bottom view of an engine main block including a cylinder block and a half crankcase coupled thereto.

FIG. 5 is an end view showing an end portion of a cylinder block on a half crankcase side.

FIG. 6 is a top view of the mount case.

FIG. 7 is a cross-sectional view of the mount case coupled to the cylinder block, cut along an end surface of the cylinder block.

FIG. 8 is a schematic sectional view taken substantially along the line VIII-VIII in FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outboard motor, 2 ... Extension case, 3 ... Gear case, 4 ... Engine, 5 ... Engine cover, 6 ... Mounting device, 7 ... Stern, 8 ... Bracket, 9 ... Tilt shaft, 10 ... Swivel case, 11 ... Swivel Shaft, 12 connecting member, 13 crankshaft, 14 drive shaft, 15 forward / reverse switching device, 16 propeller shaft, 17 propeller, 18 cylinder block, 19 half crankcase, 20 cylinder head, 21 ... cylinder head cover, 22 ... bolt, 23 ... crank chamber, 24 ... cylinder, 25 ... piston, 26 ... connecting rod, 27 ... bolt, 28 ...
Bearing part, 29: Valve train chamber, 30: Cam shaft, 31: Drive pulley, 32
... driven pulley, 33 ... belt, 34 ... flywheel, 35
... screws, 36 ... generator, 37 ... intake valve, 38 ... exhaust valve, 39 ... rocker arm, 40 ... intake port, 41 ... intake pipe, 42 ... carburetor, 43 ... exhaust passage, 44 ... exhaust port, 45 ... electrical equipment Box, 46 ... Starter motor, 47 ... Ring gear, 48 ... Overhang, 49, 50 ... Enclosure wall, 51 ... Recess, 52 ... Packing surface, 53 ... Bottom wall, 54 ... Packing surface, 55 ... Boss, 56 ... Bearing Wall, 57… Gap, 58… Round hole, 59… Seal piece, 60… Communication hole, 61… Flywheel chamber, 62… Mount case, 63… Enclosure wall, 64… Recess, 65… Mount rubber, 66… Bolt, 67 ... holding member,
68… oil pan, 69… strainer, 70… oil suction pipe,
71 ... oil suction passage, 72 ... oil pump, 73 ... suction port,
74… oil filter, 75… oil passage, 76, 77… oil passage,
78… Crank pin bearing, 79… Cylinder wall part, 80… Oil hole, 81… Oil drop hole, 82, 83… Oil return passage, 84
... oil return port, 85 ... oil passage, 86 ... oil return port,
87 ... oil return passage, 88 ... oil return pipe, 89 ... under case, 90 ... under cover, 91 ... oil supply passage.

Claims (3)

(57) [Claims] 1. A vertical, in which a crankshaft is vertically oriented, a flywheel is provided at a lower end portion protruding through a bottom wall of a crankcase of the crankshaft, and an oil pan is provided below the flywheel. In the engine,
An oil return passage for communicating the crank chamber and the oil pan is formed on a side of the flywheel, and the oil return passage is located below the flywheel and is a first up-down direction that communicates with the oil pan. A vertical engine comprising: a passage portion; and a second passage portion which extends while inclining downward at an outer peripheral portion of the flywheel toward the first passage portion. 2. The vertical engine according to claim 1, wherein said oil return passage is formed in a housing covering said flywheel. 3. An outboard motor mounted on a stern by a mounting device having a tilt shaft and a swivel shaft, wherein a drive shaft extending in a vertical direction is disposed at a position forward of the main body of the outboard motor, that is, at a position close to the stern. A vertical engine having a vertically oriented shaft mounted thereon, wherein the vertical engine is mounted with the crankshaft disposed forward and the cylinder head disposed rearward, and penetrated through the crankcase bottom wall of the crankshaft. A flywheel is provided at the lower end protruding and the drive shaft is connected, an oil pan is provided at the rear of the drive shaft, and an oil return passage communicating the crank chamber and the oil pan is provided on a side of the flywheel. A first vertical passage portion communicating with the oil pan, and an outer peripheral portion of the flywheel. And a second passage portion extending downward while being inclined toward the first passage portion.