JP2001106188A - Outboard motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outboard motor capable of reducing the tilt-up load and improving the operatability. SOLUTION: This outboard motor 5 comprises a bracket unit 3 fixed to a hull 2, a casing unit 6 mounted at a back of a tilt shaft 4 horizontally mounted while supported on this bracket unit 3, held by the tilt shaft 4, and rotatable about the tilt shaft, and a four-cycle engine E loaded on the upper side of the casing unit 6, the four-cycle engine E has a valve driving means B including a valve for opening and closing at least one of an intake port to a combustion chamber 62 formed on a cylinder head 31a, and an exhaust port in interlocking with a crank-shaft 36 mounted on a crank chamber 23, and a cam formed on a cam shaft, and driving the valve, the crank chamber 23 is mounted at a hull side, the cylinder head 31a is mounted on the side opposite to the hull side, a driving shaft means C is connected to an output shaft 59 of the engine and accommodated in the casing unit 6, a propeller 8 is mounted on an end of the driving shaft means C, the driving shaft means C is connected to the cam shaft 50, and the crankshaft 36 is mounted on the hull side with respect to the cam shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an outboard motor equipped with a four-stroke engine.

[0002]

2. Description of the Related Art Such an outboard motor is inexpensive and small.
It has a cycle engine.

[0003]

However, in recent years, the use of a four-cycle engine has been demanded from the viewpoint of exhaust gas purification. However, when the four-stroke engine is mounted on the outboard motor, the load when tilting up the outboard motor with the tilt axis supported by the bracket unit fixed to the hull and arranged horizontally as a fulcrum increases, There are problems such as poor sex.

The present invention has been made in view of the above circumstances, and has as its object to provide an outboard motor capable of reducing a tilt-up load and improving operability.

[0005]

Means for Solving the Problems In order to solve the above problems and achieve the object, the present invention has the following constitution.

According to a first aspect of the present invention, there is provided a bracket unit fixed to a hull, and arranged behind a tilt shaft supported by the bracket unit and arranged in a horizontal direction and held by the tilt shaft. An outboard motor including a casing unit rotatable around a tilt axis and a four-cycle engine mounted on an upper side of the casing unit, wherein the four-cycle engine is connected to a combustion chamber formed in a cylinder head. A valve that opens and closes at least one of an intake port and an exhaust port of the crankshaft in conjunction with a crankshaft disposed in a crankcase, and a valve drive unit that drives a valve including a cam formed on a camshaft; A drive arranged with the chamber on the hull side and the cylinder head on the non-hull side and connected to the output shaft of the engine and housed in the casing unit Means having a propeller disposed at an end of the drive shaft means, the drive shaft means being connected to the camshaft, and the crankshaft being disposed on the hull side with respect to the camshaft. Outboard motor. ].

According to the first aspect of the present invention, the crank chamber is disposed on the hull side and the cylinder head is disposed on the non-hull side, and the drive shaft means connected to the output shaft of the engine and housed in the casing unit is provided. The propeller is disposed at the end of the drive shaft means, and the drive shaft means is connected to the camshaft, and the crankshaft is disposed on the hull side with respect to the camshaft. As a result, the tilt-up load can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the description of the embodiments and the drawings.

First, FIGS. 1 to 7 show an embodiment applied to an outboard motor, FIG. 1 is a side view showing a state in which the outboard motor is attached to a hull, and FIG. 2 is an engine part of the outboard motor. FIG. 3 is a longitudinal sectional view, FIG. 3 is a sectional view taken along the line III-III of FIG.
5 is a sectional view taken along the line VV in FIG. 2, FIG. 6 is a sectional view taken along the line VI-VI in FIG. 2, and FIG.
FIG. 4 is a diagram showing intake and exhaust timings.

In the marine vessel 1 of this embodiment, a bracket unit 3 is fixed to a stern plate 2a of a hull 2, and a tilt shaft 4 arranged in a horizontal direction is attached to the bracket unit 3.
Is supported. Behind the tilt shaft 4, a casing unit 6 of the outboard motor 5 is arranged. The casing unit 6 is rotatably held by a tilt bracket 3a, and the tilt bracket 3a is held by the tilt shaft 4 and a bracket body. 3b, it is possible to tilt around the tilt axis if the engagement is released.

The casing unit 6 comprises a top cowling 6a, an upper case 6b and a lower case 6c, and the top cowling 6a further comprises an upper cowl 6a1 and a bottom cowl 6a2. The upper case 6b has an upper part covered by an engine plate 15 and a lower part covered by a lower case 6c, respectively, and a propeller 8 is mounted on the lower case 6c. Above the engine plate 15, the four-cycle engine 7 and the bottom cowl 6a2 are placed so as to cover the four-cycle engine 7. Bottom cowl 6a
2, the upper cowl 6a1 can be opened with the hull side as a fulcrum, and the bottom cowl 6a2 can be opened left and right. This enables maintenance of the four-cycle engine E.

The outboard motor 5 has a drive shaft 9 in which the output shaft 59 of the four-stroke engine E is arranged vertically, and which is connected to the lower end of the output shaft 59 and is arranged vertically. 9, a pinion 502 arranged at the lower end portion
A propeller shaft 501 connected to the drive shaft 9 is disposed by a forward / backward and neutral switching device 500 having a bevel gear mechanism including a pair of forward / backward reducing gears 503a and 503b meshing with the pinion 502. Propeller shaft 5
01 with a propeller.

Conventionally, when the rotation of the crankshaft 36 is transmitted to the propeller 8 after being reduced, the speed is reduced by a bevel gear mechanism. On the other hand, in the outboard motor 5 of this embodiment, since the drive shaft 9 has already been reduced by half with respect to the rotation of the crankshaft 36, the reduction by the bevel gear mechanism is unnecessary or the reduction ratio ( = Drive shaft rotation speed / propeller shaft rotation speed), the reduction gear 50 arranged perpendicular to the propeller shaft 501 arranged in the front-rear direction.
3a, 503b can be made smaller in size, and the reduction gear 503
a, the projected area in the traveling direction of the lower case 6c accommodating the 503b can be reduced and the fluid resistance can be reduced. Also,
By using the camshaft 50 as the output shaft 59 and increasing the speed of the bevel gear mechanism to increase the overall reduction ratio (= crankshaft rotation speed / propeller rotation speed), the rotational torque on the crankshaft 36 is reduced by the propeller. Since a larger rotational torque can be provided on the shaft 501 and a large propulsive force can be obtained, acceleration can be improved.
Also, in this case, the external shape of the reduction gears 503a and 503b can be reduced, or the fluid resistance can be reduced or kept the same by making the reduction gears 503a and 503b equivalent to the conventional one.

An intake manifold 11 is mounted on one side of the engine body 10 of the four-cycle engine E, and an exhaust manifold 12 is mounted on the other side. The intake manifold 11 has a carburetor 1
3. The intake silencer 14 is connected in this order, and the intake silencer 14 is sucked in by the intake system constituted by these components. The exhaust manifold 12 has cooling fins 12a, and the exhaust manifold 12 is connected to an engine plate 15 on which the engine body 10 is mounted. An exhaust passage 16 is formed in the engine plate 15, and exhaust gas from the exhaust manifold 12 is guided to an expansion chamber 18 formed in the upper case 6 b through the exhaust passage 16, and is exhausted by an exhaust system formed by these. Is done. The upper case 6b is supported by the engine plate 15, and the upper case 6b is rotatably supported by the tilt bracket 3a via a bush 19 and a damper rubber 20.

A fuel tank 21 is mounted above the engine body 10, and an injection portion 21a of the fuel tank 21 is provided.
Project upward from the upper cowl 6a1, and the cap 2
2 is removed and fuel is supplied. The carburetor 13 guides the fuel from the fuel tank 21 using the pressure pulsation of the crank chamber 23 of the four-cycle engine E, returns the excess fuel to the fuel tank 21, and supplies the fuel to the intake passage in any posture. You can do it.

The engine body 10 includes a head cover 30
And a cylinder body of a cylinder block 31 integrally formed with a cylinder head 31a, and a crankcase 32 joined to the cylinder block 31. The cylinder block 31 is provided at the center thereof with a single cylinder 34 for accommodating a piston 33, and the piston 33 reciprocates in the cylinder 34. A large number of cooling fins 31b are provided on the outer periphery of the cylinder body.

In the crankcase 32, a pair of case halves 32a and 32b are joined to each other by a plurality of bolts (not shown) arranged on the periphery thereof, and a crankshaft 36 connected to a piston 33 via a connecting rod 35 is connected to both ends. A crankshaft 36, which is axially supported between the case halves 32 a and 32 b by ball bearings 37 and 38, sealed by seal members 39 and 40, and arranged vertically, passes through the crankcase 32.

A flywheel magnet 41 is disposed at the upper end of the crankshaft 36, and a manual starter means 42 is disposed above the flywheel magnet 41. Flywheel magnet 4
1 is covered by a case 43 and the flywheel 4 of the flywheel magnet 41 is rotated by rotation of the crankshaft 36.
4 rotates in conjunction with it, the outside air is sucked downward from the louver 45 of the upper cowl 6a1, water droplets are separated, further outside air is introduced from the suction hole 43a of the case 43, and further outside air is drawn from the suction hole 43a of the case 43. The shroud 46 that is introduced and covers the engine main body 10 flows through an air flow path 47 formed between the shroud 46 and the outer periphery of the engine main body 10 to cool the engine main body 10.
Is discharged to the outside through the opening of the bottom cowl 6a2 penetrating therethrough. At this time, the exhaust manifold 12 is cooled.

The manual starter means 42 includes a cover 48
By pulling the starter lip 49, the rotating member of the manual starter means 42 engages with the plate 44a of the flywheel 44 to forcibly rotate the crankshaft 36, thereby starting the engine.

At the other end of the lower end of the crankshaft 36, a driving gear 52 for driving a driven gear 51 arranged on the camshaft 50 is arranged. The camshaft driving means A for transmitting to the camshaft 50 is constituted. The drive gear 52 is sealed by a seal member 53. The upper end of the camshaft 50 is supported by the cylinder block 31 of the cylinder body via a ball bearing 54, and the lower end thereof is connected to a cover member 55 by a ball bearing 56.
And is sealed by a seal member 57. The cover member 55 is joined to the cylinder block 31, and a gear chamber 58 for accommodating the driven gear 51, the driving gear 52, and the like is formed at the joint.

The drive shaft 9 is coaxially connected to the camshaft 50 by spline engagement. An output shaft 59 from the engine body 10 is constituted by the camshaft 50, and the output shaft 59 is disposed vertically. The drive shaft 9 is connected to the lower end of the output shaft 59 and is disposed vertically. As described above, the camshaft driving means A is arranged in the middle of the power transmission from the crankshaft 36 to the output shaft 59. In addition, by disposing the camshaft 50 in the projection range in the crankshaft direction, the engine body 10 and the upper case 6b can be made compact when viewed from above, and a space at the stern can be secured, and hang-up, netting, and getting on and off can be performed. It will be easier.

The intake passage 60 and the exhaust passage 61
2, and an intake port 60 b and an exhaust port 61 b to the combustion chamber 62 are opened and closed by valve driving means B. A spark plug 64 is provided on the cylinder head 31a.
It is attached to face.

The valve driving means B includes an intake valve 65 and an exhaust valve 66 for opening and closing the intake port 60b and the exhaust port 61b, and a tappet 6 provided at the head of the intake valve 65 and the exhaust valve 66.
5a, 66a, springs 67, 68 for constantly biasing the intake valve 66 and the exhaust valve 66 in the closing direction, rocker arms 69, 70 for pushing the intake valve 66 and the exhaust valve 66, and adjusting the rocker arms 69, 70 Screw 69
a, push rods 91 and 92 pushed through 70a
Lock nuts 69b and 70b for preventing adjustment screws 69a and 70a from loosening, and push rod 9
The cam followers 94 and 95 are in contact with the cam followers 1 and 92 and are supported by the cam follower shaft 93, and the cam 96 formed on the cam shaft 50 that pushes the cam followers 94 and 95. That is, the driven gear 51 is provided on the upper portion of the camshaft 50, the lower portion becomes the rotational force output portion 50a, and the cam 96 is provided in the intermediate portion between the driven gear 51 and the rotational force output portion 50a.

The upper end of the cam follower shaft 93 is supported by the cylinder block 31 of the cylinder body, and the lower end is supported by the cover member 55. The valve driving means B opens and closes the intake valve 65 and the exhaust valve 66 once at the opening and closing timing shown in FIG. 7 every two rotations of the crankshaft 36.

As described above, the position of the output shaft 59 is shifted from the position of the crankshaft 36 by disposing the camshaft driving means A and the valve driving means B and using the camshaft 50 as a part of the power transmission system. It can be shifted, and the speed can be reduced to half of the crankshaft rotation speed. Further, the output shaft 59 is connected to the camshaft 5.
Since the number of rotations of the output shaft 59 is set to 0, the rotation speed of the output shaft 59 can be reduced to half of the rotation speed of the crankshaft without a special speed reducer, and the size and weight can be reduced. Moreover, since the output shaft 59 rotates in the reverse direction to the crankshaft 36 and the flywheel 44, the torque reaction force during acceleration and deceleration can be reduced.

That is, the flywheel 44, the crankshaft 36, the driving gear 50, the driven gear 51, and the camshaft 50
Constitutes a power transmission system in the engine body 10 and vibrates the engine body 10 with an inertia torque (torque reaction force) obtained by multiplying the respective moments of inertia and angular acceleration. However, flywheel 44, crankshaft 3
6 and the rotation direction of the drive gear 50, the driven gear 5
The rotation directions of 1 and the camshaft 50 are reversed, and the vector direction of the angular acceleration is also reversed, so that the integrated inertia torque is reduced. In particular, in the outboard motor 5, a large torque reaction force in which the inertia torque of the drive shaft 9 is added to the inertia torque of the output shaft is applied to the entire casing unit 6 including the upper body 6b and the lower case 6c in addition to the engine body 10. The torque reaction force acts as a force for rotating the casing unit 6 around the push 19, and acts on the steering handle 6a provided on the bottom cowl 6a2 and rotating the entire casing unit 6 for steering.
The steering load may be changed and increased, which may cause so-called steering wheel seizure. In this embodiment,
Since the rotation directions of the output shaft 59 and the drive shaft 9 and the rotation direction of the crankshaft 36 are changed, the change in the steering load is reduced, and the steering wheel is less likely to be removed.

Further, in the power transmission system including the flywheel 44, the crankshaft 36, the driving gear 50, the driven gear 51, the cam shaft 50, the drive shaft 9 and the propeller shaft 501, the engine itself may be a reciprocating type. ,
Although large torsional vibration may occur, the crankshaft 36
The cam shaft 50 and the cam shaft 50 are firmly connected by the driving gear 50 and the driven gear 51, so that there is little deviation between the crankshaft angle and the cam shaft angle (timing is correctly performed). , 95, push rod 91,
92, the rocker arms 69 and 70 move forward in accordance with the crank angle, and the intake valve 65 and the exhaust valve 66 open and close correctly at a predetermined crank angle (exhaust valve, intake valve corresponding to the crank angle shown in FIG. 7). The valve lift curve of the crankshaft 3
6 is correctly reproduced every two rotations), so that a stable engine output is always exhibited.

The cover member 55 is disposed on the upper surface of the exhaust guide 15, and the engine plate 15 is joined to the upper end of the upper case 6b constituting the casing unit 6. The upper case 6b has an upper part opened upward, and this opening is closed by the engine plate 15.

The cylinder head 31a has an intake passage 60
And an exhaust passage 61, and an exhaust passage 16 is provided in the engine plate 15.
Is connected to the cylinder block 31 of the cylinder body via the cover member 55, and the engine plate 15 is simultaneously attached to the cylinder head 31a of the exhaust manifold 12.
The exhaust passage 61 in the cylinder head 31a and the exhaust passage 16 in the engine plate 15 communicate with each other. An exhaust manifold 12 connects between an exhaust passage outlet 61a formed in the cylinder head 31a and an opening provided in a casing side wall of the engine plate 15. The lower end of the exhaust passage 16 in the engine plate 15 opens toward the upper opening of the upper case 6b.

As described above, the crank chamber 23 is arranged on the hull side and the cylinder head 31 is arranged on the non-hull side, and the drive shaft means C connected to the output shaft 59 of the engine and housed in the casing unit 6 is provided. A propeller 8 is disposed at the end of the shaft means C, and the drive shaft means C
0 and the crankshaft 36 is arranged on the hull side with respect to the camshaft 50 while keeping the distance in the front-rear direction between the drive shaft means C and the tilt shaft 4 constant. As a result, the tilting portion that rotates around the tilt shaft 4 of the outboard motor 5 moves closer to the tilt shaft side, so that the tilt-up load can be reduced.

Normally, the tilt-up is carried out by putting a hand from the hull in the upper upper corner of the rear portion of the upper cowl 6a1, or by a hydraulic or electric tilt-up device.

A valve chamber 72 is disposed adjacent to the crank chamber 23 in the case half 32 b of the crank case 32 forming the crank chamber 23, and the valve chamber 72 communicates via a check valve 71. Further, since the valve chamber 72 for storing oil is disposed on the hull side of the crank chamber 23, the tilt-up load can be reduced with respect to the oil weight.

A valve operating chamber 73 for accommodating valve operating components for pressing the end portions of the valve chamber 72 and the intake valve 65 and the exhaust valve 66.
The first oil supply path 74 that communicates with the valve operating system chamber 7
A second oil supply passage 75 communicating the lower portion of the crankcase 3 and the inside of the crank chamber 23 is disposed. The valve system housing chamber 73 includes a gear chamber 73a and a tappet chamber 73b.
3a and tappet room 73b are connected by push rod hole 73c. The first oil supply passage 74 includes an oil passage 74a in the cover member, an oil passage 74b in the cylinder block, an oil passage 74c in the cylinder head, and an oil passage 74d in the head cover. The second oil supply passage 75 is constituted by an oil passage 75a in the case half body.

The outlet of the second oil supply passage 75 is opposed to a crank chamber interlocking component consisting of the crankshaft 36, the connecting rod 35 and the piston 33. Here web 36
a. The second oil supply path 75
It is formed on the case half 32b of the crankcase 32 and passes through the gear chamber 58 on the way, so that the driven gear 51 and the driving gear 52 can be easily lubricated.

An oil communication passage 76 for communicating the first oil supply passage 74 with the crank chamber 23 is provided between the oil passage 76a in the cover member and the axis of the crank shaft 36.
The crankshaft oil passage 76b passes through the oil passage 76b.

An oil inlet 72a is provided at the top of the valve chamber 72, a cap 99 is detachably attached to the oil inlet 72a, and a drain plug 77 is provided at the bottom of the valve chamber 72. The valve chamber 72 can be used as an oil pan. In addition, since the oil inlet 72a is provided in the upper part of the valve chamber 72, the oil injection operation can be easily performed by removing the cap 99.
Further, the oil inlet 72a and the drain plug 77 are arranged concentratedly on the hull side, so that oil maintenance can be easily performed from the boat.

When the gas in the crank chamber together with the oil mist passes through the check valve 71 and enters the valve chamber 72, the oil in the valve chamber is pushed out and circulates by that amount, and passes through the check valve 71 for each reciprocation of the piston 33, and the crank chamber. Since the gas enters the valve chamber together with the oil mist, the oil at the time of injection is sequentially extruded, stays in the middle of the circulation path, and is lubricated.

The four-cycle engine E is provided with a blow-by gas discharge passage 78 that communicates the crank chamber 23 with the outside. The blow-by gas discharge passage 78 is provided with an oil mist separator 79 and an air passage 80a in the cylinder body.
, An air passage 80b in the cylinder head, an air passage 80c in the head cover, and a blow-by gas pipe 82 that connects the head cover 30 and the intake silencer 14 via a throttle 81. Oil mist separator 79
Has a cyclone chamber 79a as shown in FIG. 4, and mist-like oil is supplied from the inlet 79b to the cyclone chamber 79a.
Then, the oil portion is separated in the cyclone chamber 79a, and the blow-by gas is discharged from the discharge port 79c to the air passage 80a in the cylinder body.

In the four-cycle engine E, the valve chamber 72
The oil in the L-shaped oil pan chamber stays in the lower part of the L-shaped oil pan chamber. The valve chamber 72 is an L-shaped oil pan chamber, and an oil push-in port 74a is provided at a bottom corner thereof.
1 can be used for a vertically or horizontally mounted engine, and can be operated even when inclined.

In the operation of the four-cycle engine E, the pressure in the crank chamber 23 fluctuates as the piston 33 moves from the top dead center to the bottom dead center, and oil mist is released from the crank chamber 23 through the check valve 71. It is fed into the L-shaped oil pan chamber of the valve chamber 72, and the crank chamber 23, and further the check valve 71
Due to the pressure increase in the L-shaped oil pan chamber through the
4a1 enters the first oil supply path 74.

The oil branches off from the first oil supply passage 74 and flows through the oil communication passage 76, and circulates in the crank chamber 23 in the form of a mist due to the centrifugal action of the crank web 36 a of the crank shaft 36.

On the other hand, the oil that does not branch passes from the first oil supply path 74 to the tappet chamber 73b, the rod hole 73c and the gear chamber 73a, and circulates from the second oil supply path 75 to the crank chamber 23.

With respect to the oil reaching the outlet 76b1 of the crank web 36a from the oil passage 76b in the crankshaft of the oil communication passage 76, the pressure in the crank chamber is reduced due to the movement of the piston 33 from the bottom dead center to the top dead center. Negative pressure acts. Further, the outlet 76b of the crank web 36a
A centrifugal force also acts on the first oil, whereby the oil enters the crank chamber 23 as a mist from the outlet 76b1 of the crank web 36a.

The oil entering the tappet chamber 73b via the first oil supply path 74 stays in the lower portion, and the push rod hole 73c formed in the lower portion of the tappet chamber is opened from the tappet chamber side opening end of the push rod hole 73c. Through the inlet 75a2 of the second oil supply path 75, which opens into the gear chamber 73a, into the second oil supply path 75, and flows out of the outlet 75a1 into the crank chamber 23 when the pressure in the crank chamber drops. I do. The outlet 75a1 faces the crank web 36a, and the outflowing oil adheres to the crank web 36a and scatters in a mist state into the crank chamber 23 due to centrifugal force, and the oil exists in the mist state in the crank chamber 23. Will be.

As described above, the oil exists in the form of a mist in the crank chamber 23, and the pressure in the crank chamber rises as the piston 33 moves from the top dead center to the bottom dead center, and the oil mist is stopped. The air enters the L-shaped oil pan chamber of the valve chamber 72 together with the air in the crank chamber through the valve 71, and the pressure in the L-shaped oil pan chamber is increased. The oil in the L-shaped oil pan chamber stays in the lower portion of the L-shaped oil pan chamber in a form containing air in the crank chamber as air bubbles.

The air in the crank chamber containing the proby gas is separated from the oil mist by an oil mist separator 79, and the air passage 80a in the cylinder body, the air passage 80b in the cylinder head, the air passage 80c in the head cover,
The exhaust gas is discharged to the intake silencer 14 through the throttle 81 and the blow-by gas pipe 82, passes through the intake passage 60, and
The combustion components are combusted in the exhaust passage 6 and become exhaust gas.
Emitted from 1. The blow-by gas pipe 82 may be connected to an air cleaner or a carburetor to discharge blow-by gas to these.

Further, since the throttle 81 is provided in the blow-by gas discharge passage 78, a large amount of air in the crank chamber is prevented from flowing out, thereby preventing the crank chamber pressure and the L-shaped oil pan chamber pressure from increasing.

The oil flowing through the oil passages of the first oil supply passage 74, the second oil supply passage 75, and the oil communication passage 76 contains bubbles formed by a part of the total blow-by gas amount. However, since the amount is small, the influence on the lubricated portion is small. Further, the bubbles are partially separated in the tappet chamber 73b to increase the tappet chamber pressure, but the gas component flows out together with the oil staying in the lower part of the tappet chamber and flows from the push rod hole 73c to the gear chamber 73a,
Oil circulation becomes possible.

Further, as another embodiment of the blow-by gas discharge passage 78, an opening is provided in the upper part of the tappet chamber 73b,
A communication pipe may be connected to an intake silencer or a carburetor via a throttle, and the throttle may reduce the pressure in the tappet chamber 73b to prevent poor oil circulation from the tappet chamber 73b and to the gear chamber 73a. The amount of bubbles containing blow-by gas can be reduced.

As described above, in the oil lubrication mechanism of this embodiment, the pressure in the oil pan chamber, which is the valve chamber 72, is increased by the reciprocation of the piston 33, so that an oil pump is not required. Moreover, the oil circulation is started from the push-out port 74a1 at the lower part of the oil pan chamber, so that the oil circulation can be performed even when the oil amount in the oil pan chamber is small. Furthermore, when air is circulated, the oil circulation amount is insufficient and the lubricated part is easily damaged, and the blow-by gas is corrosive. Although easily damaged, the durability of the lubricated portion is improved by reducing the amount of blow-by gas mixed into the circulating oil.

In particular, as shown in FIGS. 2 and 9, the entrance of the second oil supply passage 75 on the tappet chamber 73 b side is
The lower portion 3b is on the tilt shaft 4 side. For this reason, even in a shallow running state in which the casing unit 6 is tilted up and the propeller 8 sails near the water surface, the tappet chamber 73b-side entrance maintains the lowermost portion of the tappet chamber 73b. Oil circulation to the chamber 73a and further to the crank chamber is smoothly performed. That is, oil circulation is enabled regardless of the usage state of the outboard motor 5. Further, since the air circulating is mixed with air bubbles of the air in the crank chamber, the specific gravity is reduced, and the tappet chamber 7
The rocker arm 6 which moves in the gear chamber 73a inside the chamber 3b
The air bubbles are crushed by the cam followers 9 and 70 and the cam followers 94 and 95 to form an oil mist.
And push rods 91 and 92 and cam follower 9
4, 95 etc. can be lubricated sufficiently. In the first oil supply path 74, air bubbles of the crank chamber air are mixed in the oil, and in the second oil supply path 75, the oil is in the form of mist or air bubbles. Regardless of the position, and regardless of the position of the tappet chamber 73b-side entrance of the second oil supply path 75 in the tappet chamber 73b, each oil supply path 7
Regardless of the shape of 4,75, the oil can be circulated.

8 to 10 show another embodiment applied to an outboard motor. FIG. 8 is a longitudinal sectional view of an outboard motor mounted on a ship, and FIG. 9 is a longitudinal sectional view of an engine portion of the outboard motor. FIG. 10 and FIG. 10 are sectional views taken along line XX in FIG.

The outboard motor 301 of this embodiment is equipped with a water-cooled four-cycle engine E, which is mounted on the outboard motor shown in FIGS. The air-cooled type and the fuel tank 21
02 are different in that they are arranged at 02, but the other components which are configured in the same way are given the same reference numerals and description thereof is omitted.

An outboard motor 301 is supported on a stern plate 302a of the hull 302 via a clamp bracket 303 and a swivel bracket 304 so that the outboard motor 301 can be tilted around a tilt shaft 360 and can be steered.

A four-stroke engine E is mounted on the upper part of the outboard motor 301, and the fuel tank 2 is mounted on the hull 302.
After the fuel is discharged from the primary pump 340 by the primary pump 340, the fuel is supplied by driving a fuel pump (not shown). The upper end of the drive shaft 9 is connected to the output shaft 59 of the four-cycle engine E, and the lower end of the drive shaft 9 has a shift rod 309, a shift cam 310, a pinion 311 and a pair of forward and backward reductions. Propeller shaft 307, propeller 308 via forward / reverse and neutral switching device 306 comprising gears 312a, 312b and a clutch dog (not shown).
Is connected. The forward / reverse and neutral switching device 306 is
The shift cam 310 is operated by the shift operation applied to the shift rod 309, and the drive shaft 9 and the propeller shaft 307 are operated.
Can be set to any of neutral, forward, and reverse states.

In the outboard motor 301 equipped with the four-cycle engine E in this manner, even if the overall reduction ratio (= crankshaft rotation speed / propeller rotation speed) is the same as that of the conventional motor, the camshaft 50 is mounted in this embodiment. The output shaft 59 is used, so that the reduction by the bevel gear mechanism is unnecessary or the reduction ratio (= drive shaft rotation speed / propeller shaft rotation speed) is smaller than that of the conventional shaft, and the propeller shaft 307 is disposed in the front-rear direction. The external shape of the reduction gears 312a and 312b arranged in the vertical direction can be reduced, the projected area in the traveling direction of the lower case 6c that accommodates the reduction gears 313a and 313b can be reduced, and the fluid resistance can be reduced. Also, by increasing the overall reduction ratio (= crankshaft rotation speed / propeller rotation speed) as compared with the conventional one, the rotation torque on the crankshaft 36 can be reduced.
Since a larger rotational torque can be obtained in the propeller shaft 307 and a large propulsion force can be obtained, acceleration can be improved. On the other hand, even in this case, the external shape of the reduction gears 312a and 312b can be reduced, or the fluid resistance can be reduced or kept the same by making the reduction gears 312a and 312b equivalent to those of the related art.

Since the torque reaction force can be reduced even when accelerating or decelerating, the entire casing unit 6 is rotated around the steering shaft 341 on the hull side from the upper case 6b to change the steering load of the steering handle 6d. The so-called handle take, which increases, can be reduced. Further, in the power transmission system extending from the crankshaft 36 to the output shaft 59, the engine itself may be of a reciprocating type, and large torsional vibration may occur. However, there is a deviation between the crankshaft angle and the camshaft angle. Since it is unlikely to occur (timing is performed correctly), the intake valve 65 and the exhaust valve 66
Opens and closes correctly at a predetermined crank angle, so that a stable engine output is always exhibited.

A water pump 330 is provided on the drive shaft 9, and cooling water is sucked from a water suction port 331 provided in the lower case 6 c by driving the water pump 330.
The cooling water is supplied to a water jacket 350 of the engine body 10 from a cooling water passage 333 formed in the engine plate 15 via a cooling water pipe 332 to cool each part.

The water manifold 3 is provided in the exhaust manifold 12.
The cooling water is guided from the water jacket 350 to the water jacket 351, and the exhaust manifold 12 is formed.
Is cooled and discharged to the expansion chamber 18 in the upper case 6b through the cooling water passage 352 formed in the engine plate 15. Here, reference numeral 17 denotes an exhaust muffler attached to the lower side of the engine plate 15 for improving output.

In each of the above embodiments, the drive gear 52 and the drive gear 52 are arranged such that the camshaft is 1 / the crankshaft in order to synchronize the valve opening / closing timing.
2 and a function as a speed reducer in the power transmission system, so that the number of parts can be reduced. Since the timing is always stable, a stable engine output can be obtained.

In this embodiment, similarly to the first embodiment, the driving gear 52 for reducing the rotation of the crankshaft 36 to 1/2 and transmitting the rotation to the camshaft 50, and the driven gear 5
1 also serves as a speed reducer in a power transmission system from the crankshaft 36 to the propeller 308, so that the size and weight of the engine E can be prevented by this much, and the lower case 6c which is below the water surface can be prevented. To increase the navigation speed by reducing the fluid resistance of the
The acceleration performance can be increased by increasing the torque. Further, since the rotation directions of the crankshaft 36 and the camshaft 50 are reversed, the inertia torque of the power transmission system can be reduced by that amount, so that the engine body 10 is not vibrated during acceleration or deceleration and does not cause vibration of the hull 302a. Further, since the torque reaction force is reduced, an increase in the steering load during acceleration or deceleration is prevented.

The driving gear 52 and the driven gear 5
1 is a part of a power transmission system from the crankshaft 36 to the camshaft 50 serving as the output shaft 59 from the engine body 10 and further to the propeller 308 serving as a load.
Although it is affected by torsional vibration, the timing function between the crankshaft angle and the camshaft angle is not lost because of the gear mechanism. For this reason, a stable engine output can be exhibited, and more stable navigation is possible. Also, the casing unit 6
Even if the center of gravity is behind the hull 302 a from the tilt shaft 360, the engine body 10 is moved horizontally toward the hull in the horizontal direction because the crankshaft 36 is disposed forward of the cam shaft 50, which is coaxially extended with the drive shaft 9. As the horizontal distance from the tilt shaft 360 to the center of gravity of the casing unit 6 becomes shorter, the moment for tilting up about the tilt shaft 360 becomes smaller, and the tilt-up becomes easier.

[0063]

As described above, according to the first aspect of the invention, the crank chamber is disposed on the hull side and the cylinder head is disposed on the non-hull side, and the drive is connected to the output shaft of the engine and housed in the casing unit. Shaft means, a propeller is arranged at an end of the drive shaft means, and the drive shaft means is connected to the camshaft, and the crankshaft is arranged on the hull side with respect to the camshaft. Above the hull, the tilt-up load can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view showing a state in which an outboard motor is attached to a hull.

FIG. 2 is a longitudinal sectional view of an engine portion of the outboard motor.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a cross-sectional view of an oil mist separation unit.

FIG. 5 is a sectional view taken along the line VV of FIG. 2;

FIG. 6 is a sectional view taken along the line VI-VI of FIG. 2;

FIG. 7 is a diagram showing intake and exhaust timings.

FIG. 8 is a longitudinal sectional view of an outboard motor mounted on a ship.

FIG. 9 is a longitudinal sectional view of an engine portion of the outboard motor.

FIG. 10 is a sectional view taken along line XX of FIG. 9;

[Explanation of symbols]

 2 Hull 3 Bracket unit 4 Tilt shaft 5,301 Outboard motor 6 Casing unit 8,308 Propeller 9 Drive shaft 10 Engine main body 23 Crank chamber 31a Cylinder head 32 Crank case 33 Piston 34 Cylinder 35 Connecting rod 36 Crank shaft 50 Cam shaft 51 Cover Drive gear 52 Drive gear 59 Output shaft 60 Intake passage 62 Combustion chamber 71 Check valve 72 Valve chamber 73 Valve train accommodating chamber 73a Gear chamber 74 First oil supply path 75 Second oil supply path 501 Propeller shaft E Four-cycle engine A Cam shaft drive means B Valve drive means C Drive shaft means

Claims (1)

[Claims] 1. A bracket unit fixed to a hull,
A casing unit supported by the bracket unit and disposed behind a horizontally arranged tilt shaft and held by the tilt shaft and rotatable around the tilt shaft; and a casing unit mounted on the upper side of the casing unit. An outboard motor including a four-cycle engine, wherein at least one of an intake port and an exhaust port to a combustion chamber formed in a cylinder head is interlocked with a crankshaft disposed in a crankcase. Valve that opens and closes,
A valve driving means including a cam formed on a camshaft and driving a valve is provided.The crank chamber is disposed on a hull side, the cylinder head is disposed on a non-hull side, and the casing unit is connected to an output shaft of an engine. A drive shaft means to be housed, a propeller disposed at an end of the drive shaft means, the drive shaft means being connected to the camshaft, and the crankshaft being disposed on the hull side with respect to the camshaft; An outboard motor characterized in that: