JP2001115814A - Four cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a four cycle engine which is lubricated in every operating attitude of an engine with a good efficiency without enlarging. SOLUTION: This engine E is provided with a cylinder body 10 and a crank case 32 for forming a crank chamber 23, a valve chamber 72 is disposed which is disposed adjacent to the crank chamber 23 and which is communicated through a check valve 71, a first oil supplying passage 74 for communicating the valve chamber 72 and a valve system housing chamber 23, and a second oil supplying passage 75 for communicating a lower part of the valve system housing chamber and an inside of the crank chamber 23, and an outlet of the second oil supplying passage 75 is opposed to the crank shaft 36 and an interlocking parts in the crank chamber. The crank shaft 36 is vertically disposed, a driving gear 52 and a driven gear 51 are disposed on a lower end part of the crank shaft, a gear chamber 73a is disposed so as to house the driving gear 52 and the driven gear 51, and the second oil supplying passage 75 is made to pass the gear chamber 73a on the way thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-stroke engine used for a power source such as an outboard motor, a lawn mower, a scooter, or a general-purpose engine.

[0002]

2. Description of the Related Art As an engine used for such a power source, an inexpensive and small two-stroke engine is widely used.

[0003]

However, in recent years, the use of a four-cycle engine has been demanded from the viewpoint of exhaust gas purification. However, a four-stroke engine needs to circulate and store oil exclusively for lubrication.
That makes the engine bigger.

[0004] In an engine used for a power source such as an outboard motor, a lawnmower, a scooter, or a general-purpose engine,
It is necessary to reliably lubricate each part of the engine regardless of the operating posture of the engine.

The present invention has been made in view of the above circumstances, and has as its object to provide a four-stroke engine that can efficiently lubricate any operating posture without increasing the size. I do.

[0006]

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 the first aspect of the present invention, there is provided a crankshaft having a cylinder body in which a cylinder in which a piston reciprocates is formed, and a crankcase forming a crank chamber accommodating a crankshaft together with the cylinder body. A first valve chamber that is adjacent to the chamber and communicates via a check valve, and that communicates the valve chamber with a valve operating chamber that houses a valve operating component that presses an end of the check valve; An oil supply path, a second oil supply path communicating between the lower part of the valve train accommodating chamber and the crank chamber are arranged, and an outlet of the second oil supply path is opposed to a crank chamber interlocking component composed of a crank shaft, a connecting rod and a piston. A four-stroke engine, characterized in that: ].

According to the first aspect of the present invention, by arranging the check valve, it is possible to circulate the oil by the fluctuation of the pressure in the crank chamber without using an oil pump. Also, when the circulating oil enters the crank chamber from the outlet of the second oil supply path, it collides with the interlocking components of the interlocking crank chamber and is converted into mist by the action of centrifugal force. Since the gas in the crankcase circulates, the amount of oil in the oil circulation path can be reduced. In addition, no special tool is required to convert the oil into mist, especially when using a stirrer attached to the crankshaft to convert the oil into mist. Thus, there is a possibility that the engine becomes larger in the crankshaft direction. However, this is not necessary, the engine can be made compact, and the valve train can be lubricated regardless of the attitude of the engine.

According to a second aspect of the present invention, there is provided a crankshaft having a cylinder body in which a cylinder in which a piston reciprocates is formed, and a crankcase forming a crank chamber accommodating a crankshaft together with the cylinder body. A first valve chamber that is adjacent to the chamber and communicates via a check valve, and that communicates the valve chamber with a valve operating chamber that houses a valve operating component that presses an end of the check valve; An oil supply path, a second oil supply path communicating between the lower part of the valve train accommodating chamber and the crank chamber is arranged, and an outlet of the second oil supply path is opposed to a crank chamber interlocking component consisting of a crank shaft, a connecting rod and a piston, The crankshaft is arranged vertically, a driving gear is arranged at a lower end of the crankshaft, a driven gear meshing with the driving gear is arranged on the camshaft, and a gear chamber for accommodating the driving gear and the driven gear is provided. Oy 4-cycle engine supply path, characterized in that to pass through the gear chamber in the middle. ].

According to the second aspect of the present invention, the crankshaft is vertically arranged, and a driving gear is provided at the lower end of the crankshaft.
A driven gear meshing with the driving gear is disposed on the camshaft, and a gear chamber for accommodating the driving gear and the driven gear is provided. The second oil supply passage passes through the gear chamber halfway, so that the gear lubrication is performed. Is easy.

According to a third aspect of the present invention, there is provided a four-stroke engine according to the first or second aspect, wherein an oil inlet to which a cap is detachably attached is disposed in the valve chamber. ].

According to the third aspect of the present invention, since the oil inlet for detachably attaching the cap is disposed in the valve chamber, the valve chamber can be used as an oil pan.

According to a fourth aspect of the present invention, there is provided a four-stroke cycle according to any one of the first to third aspects, wherein a blow-by gas discharge path communicating the crank chamber with the outside is arranged. engine. ].

According to the fourth aspect of the present invention, since the blow-by gas discharge path that connects the crank chamber to the outside is arranged, the amount of gas in the crank chamber that enters the valve chamber is reduced, thereby reducing the oil circulation capacity. However, the amount of blow-by gas in contact with the valve train can be reduced, and the durability of the lubricated portion is improved.

[0015]

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 where 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 disposed horizontally in the bracket unit 3 is provided.
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. 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 vertically arranged, and which is connected to the lower end of the output shaft 59 and is vertically arranged. 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 has two crankshafts. 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 arranged at the upper end of the crankshaft 36, and a manual starter means 42 is arranged 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 arranged in a vertical direction. 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 are
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, 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, the position of the output shaft 59 is shifted from the position of the crankshaft 36. 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 disposed on the hull side and the cylinder head 31 is disposed 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 is provided. The propeller 8 is arranged at the end of the means C, and the drive shaft means C is provided with a camshaft 50.
And the crankshaft 36 is disposed on the hull side with respect to the camshaft 50 while keeping the distance between the drive shaft means C and the tilt shaft 4 constant in the front-rear direction. , The center of gravity of the tilting portion that rotates around the tilt shaft 4 of the outboard motor 5 is shifted toward the tilt shaft side, so that the tilt-up load can be reduced.

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

In the case half 32b of the crankcase 32 forming the crank chamber 23, a valve chamber 72 is arranged adjacent to the crank chamber 23. The valve chamber 72 communicates with 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.

Further, an oil communication passage 76 for communicating the first oil supply passage 74 with the crank chamber 23 is provided between the oil passage 76 a 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 an upper portion 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 every 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.

During 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 via 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 path 74 and flows through the oil communication path 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 through the tappet chamber 73b, the rod hole 73c and the gear chamber 73a from the first oil supply path 74, and circulates from the second oil supply path 75 to the crank chamber 23.

For 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 due to the movement of the piston 33 from the bottom dead center to the top dead center is reduced. 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 passage 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 to 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 increases with the movement of the piston 33 from the top dead center to the bottom dead center. 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 does not flow out to prevent 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 reciprocating motion 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 13, the inlet of the second oil supply passage 75 on the tappet chamber 73b side is located below the tappet chamber 73b and on the tilt shaft 4 side. For this reason, even in a shallow water navigation 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 keeps the lowermost part of the tappet chamber 73b. Oil circulation to the chamber 73a and further to the crank chamber 23 is smoothly performed.
That is, oil circulation is enabled regardless of the usage state of the outboard motor 5.

Further, since the air circulating contains air bubbles in the crank chamber, the specific gravity is reduced, and the rocker arms 69 and 70 and the cam followers 94 and 95 that move in the tappet chamber 73b and the gear chamber 73a are used. The bubbles are crushed into an oil mist, and the rocker arm 69,
70, the push rods 91 and 92, and the cam followers 94 and 95 can be sufficiently lubricated. 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 an embodiment applied to a lawn mower, FIG. 8 is a side view of the lawn mower, FIG. 9 is an enlarged side view of a part of the lawn mower, and FIG. It is sectional drawing of the engine part of a lawnmower.

The lawn mower 101 of this embodiment has four
A cycle engine E is mounted. The four-cycle engine E has the same configuration and effects as those mounted on the outboard motor shown in FIGS. Description is omitted.

The lawn mower 101 has a cutter deck 104 supported by a pair of left and right wheels 102 and 103, which are respectively disposed in front and rear. The cutter deck 104 is made of aluminum casting, resin, or sheet metal, and a handle 105 is attached to the cutter deck 104 so as to protrude rearward and upward from a rear portion. When the handle 105 is pushed forward, the wheels 102 and 103 roll on the grass surface 106 and the cutter deck 104 moves forward.

A 4-cycle engine E is mounted on the cutter deck 104, and the fuel tank 21 is provided with stays 130,
131 is supported by the engine body 10. In this four-stroke engine E, a crankshaft 36 is disposed in a vertical direction, and a cutter blade 113 extending in a horizontal direction via a clutch 112 is detachably attached to a lower end of a drive shaft 9 connected to a camshaft 50 by a bolt 114. Screwed. In the four-cycle engine E, by increasing the engine speed, a large output can be obtained even with a small displacement and small and light engine, and a speed reduction device is not particularly necessary when decelerating to a required speed of connected equipment. The size and weight can be reduced.

Cutting blades 113a are formed at both ends of the cutter blade 113. The 4-stroke engine E is driven to rotate the cutter blade 113 in the direction shown by the arrow in FIG. If it moves, the cutting blade 113a will cut the turf on the turf surface 106 one by one with the forward movement.

The lower surface of the cutter deck 104 has a circular shape in plan view that covers the upper surface and the outer peripheral surface of the rotation trajectory of the cutter blade 113, that is, the cutter deck 104 also serves as a housing 115 for the cutter blade 113. The cutter deck 104 includes a housing 11.
A pair of left and right cover plates 120 extending in the front-rear direction is provided so as to cover the gap 119 between the lower end on both sides of the side 5 and the grass surface 106.

A grass bag 118 is connected to the rear of the housing 115 and is formed of a ventilated resin steel material. Then, when the cutter blade 113 is rotated, the wing blades 116 are also rotated, and the grass cut by the cutter blade 113 is rotated by the wing blades 1.
When it reaches the rear of the housing 115 with the airflow created by 16, it is thrown into the grass bag 118. Here, the airflow passes through the grass bag 118 and is discharged to the outside, while the cut grass is left and stored in the grass bag 118. In this state, if the cutter deck 104 is moved forward by the pushing operation of the handle 105, the lawn mowing operation as described above is sequentially performed with this forward movement. Reference numeral 21a is an engine cover that covers the upper part of the four-cycle engine E.

In this lawn mower 101 as well, if the torque reaction force is large, rolling around the drive shaft 9 may occur and the running track may be displaced, or the whole may greatly vibrate. Since the rotation direction of the drive shaft 9 and the rotation direction of the crankshaft 36 are changed,
The torque reaction force can be reduced, the running track can be prevented from being shifted, and the vibration caused by the torque reaction force can be suppressed. Further, the cutter blade 11 is moved from the crankshaft 36.
In the power transmission system up to 3, the engine itself may be of the reciprocating type, causing large torsional vibration, but there is little deviation between the crankshaft angle and the camshaft angle. Therefore, since the intake valve 65 and the exhaust valve 66 open and close correctly at a predetermined crank angle, a stable engine output is always exhibited.

FIG. 11 shows an embodiment applied to a general-purpose engine, and FIG. 11 is a sectional view of the general-purpose engine.

The general-purpose engine 201 of this embodiment has a four-cycle engine E mounted thereon. The four-cycle engine E has the same configuration as that of the outboard motor shown in FIGS. Since they have the same operation and effect, the same reference numerals are given and the description is omitted.

The general-purpose engine 201 has a frame body 205 constituted by a pair of left and right annular support frames 202 arranged vertically and connected by a pair of front and rear frame pipes 203 and 204 arranged vertically. The engine body 10 is arranged in the frame 205. The lower portion of the support frame 202 of the frame 205 is fixed to the installation surface 207 by an anchor stay 206. The lower part of the engine body 10 is supported via a mount 209 on a stay 208 provided at the lower part of the support frame 202 and connected and fixed to the left and right support frames 202, and the upper part of the engine body 10 is provided on the upper part of the support frame 202. A mount 211 is mounted on a stay 210 connected and fixed to the left and right support frames 202.
, And has a support structure that suppresses vibration of the engine body 10.

The four-stroke engine E is mounted so that the crankshaft 36 is oriented horizontally, and various devices are connected to an output shaft 59 constituted by a camshaft 50. The fuel tank 21 is disposed above the frame 205, and a fuel supply pipe 220 for supplying fuel to the engine is connected to the fuel tank 21. The fuel cock 221 disposed on the fuel supply pipe 220 is connected to a stay 22 fixed to the support frame 202.
2 attached. In the four-cycle engine E, by increasing the engine speed, a large output can be obtained even with a small displacement and small and light engine, and a speed reduction device is not particularly necessary when decelerating to a required speed of connected equipment. It is possible to reduce the size and weight of the frame 205
It is mounted compactly.

By setting the crankshaft 36 below the camshaft 50 which is the output shaft 59, the four-stroke engine E can be arranged below while the position of the output shaft 59 is raised. The overall height can be reduced. Furthermore, by keeping the cylinder 34 in the horizontal direction while maintaining the vertical arrangement of the crankshaft 36 and the camshaft 50, the overall height of the general-purpose engine 201 can be further reduced.

The general-purpose engine 201 is also connected to the general-purpose engine 20 via the anchor stay 206.
If the torque reaction force is large when the motor 1 is simply placed on the ground, there is a possibility that the crankshaft 36 rolls and the grounding of the anchor stay 206 is broken, so that the output shaft 59 cannot drive the load correctly. Output shaft 5
9, the rotation direction of the crankshaft 36 is changed, so that the torque reaction force can be reduced, the correct installation of the anchor stay 206 can be prevented, and the vibration caused by the torque reaction force can be prevented. Can be suppressed. 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 may cause a large torsional vibration. It is difficult (timing is performed correctly),
Since the intake valve 65 and the exhaust valve 66 open and close correctly at a predetermined crank angle, a stable engine output is always exhibited.

FIGS. 12 to 14 show another embodiment applied to an outboard motor. FIG. 12 is a longitudinal sectional view of an outboard motor mounted on a ship, and FIG. 13 is a longitudinal sectional view of an engine portion of the outboard motor. FIG. 14 is a sectional view taken along line XIV-XIV 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 a hull 302 via a clamp bracket 303 and a swivel bracket 304 so as to be tiltable around a tilt shaft 360 and steerable.

The four-stroke engine E is mounted on the upper part of the outboard motor 301, and the fuel tank 2 is disposed 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.

As described above, in the outboard motor 301 equipped with the four-cycle engine E, even if the overall reduction ratio (= crankshaft rotation speed / propeller rotation speed) is the same as in the prior art, 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.

Further, 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 exhaust manifold 12 has a water jacket 3
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.

FIG. 15 is a power transmission diagram as viewed from the top of the scooter, showing an embodiment applied to the scooter.

The scooter 600 has a steering handle 601 and a front wheel 602 at a front portion, and a rear wheel 603 at a rear portion. A two-cylinder four-cycle engine E is mounted below a seat (not shown) at the center. The drive gear 5 is provided at the end of the crankshaft 36.
2 are arranged, and the drive gear 52 rotationally drives the driven gear 51 held by the camshaft 50 arranged parallel to the crankshaft 36. The flywheel 44 is arranged at one end of the camshaft 50, and the other end serves as an output shaft 59 to the continuously variable reduction device 611.

The four-cycle engine E is mainly provided with the continuously variable reduction device 611, the front bevel gear mechanism 612, and the drive shaft 61.
3. A power transmission device 610 including a rear bevel gear 614 is connected. The rotational force of the crankshaft 36 is reduced to half and transmitted to the camshaft 50, and the centrifugal stepless speed reducer 6
The speed is further reduced at 11 and transmitted to the rear wheel 603 via the front bevel gear mechanism 612, the drive shaft 613, and the rear bevel gear 614.

Also in this embodiment, since the overall reduction ratio (= crankshaft rotation speed / rear wheel rotation speed) can be increased, the engine can be made smaller and faster than the conventional one, and the engine weight can be reduced. Can be made small and compact. In addition, the stepless reduction gear 61
In No. 1, although the transmission force is large, the rotation speed can be reduced, so that the centrifugal force acting on the belt 61la can be reduced. In addition, since the flywheel 44 is disposed on the camshaft, torque fluctuations of the power transmission system from the crankshaft 36 to the rear wheel 603 due to the crank mechanism can be reduced even if the weight of the flywheel 44 is reduced, thereby reducing the weight. Becomes possible.

Further, in this embodiment, the crankshaft 36, the driving gear 52, the driven gear 51, the continuously variable transmission reduction mechanism 611, the front bevel gear mechanism 612, Drive shaft 613,
Even when the power transmission system reaching the rear bevel gear mechanism 614 and the rear wheel 603 generates torsional vibration, the relationship between the camshaft angle and the crank angle is always maintained in a predetermined relationship by the driving gear 52 and the driven gear 51. Time synchronization function,
Gas exchange in the combustion chamber is always performed stably regardless of torsional vibration, and a stable engine output can be obtained.

Further, when the flywheel 44 is stopped from being disposed at the end position 50B of the camshaft 50 and is disposed on the crankshaft 36 (for example, the end position 36A), the camshaft 50 is driven. Since the cam 59 is arranged on one side and the rotational force output section 50a is provided on the other side with the arrangement site of the gear 51 as a boundary, the camshaft 50 itself is less likely to generate torsional vibration, Since the arrangement portion of the cam 59 is not twisted with respect to the arrangement portion of the trick drive gear 51, the cam shaft angle in the arrangement portion of the cam 59 with respect to the crank angle is always maintained in a predetermined relationship, and is stable. Engine power can be obtained.

Further, the arrangement of the flywheel 44 at the end position 50B of the camshaft 50 is stopped, and the camshaft 5 is stopped.
Similarly, in the case where the cam 59 is disposed at the end position 50C above the cam 59, the cam 59 is not twisted relative to the driven gear 51. Is always maintained in a predetermined relationship, and a stable engine output can be obtained. In addition, the inertial mass of the flywheel 44 can be made smaller than when the flywheel 44 is attached to the crankshaft.

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 with respect to 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.

[0090]

As described above, according to the first aspect of the present invention, by arranging the check valve, the oil circulation can be performed by the pressure fluctuation of the crank chamber without using an oil pump. Further, when the circulating oil enters the crank chamber from the outlet of the second oil supply path, it collides with an interlocking part of the interlocking crank chamber, and is mist-formed by the action of centrifugal force. At the same time, the gas in the crankcase circulates, so that the amount of oil in the oil circulation path can be reduced. In addition, no special tool is required to convert the oil into mist, especially when using a stirrer attached to the crankshaft to convert the oil into mist. And the engine may grow in the crankshaft direction,
This eliminates the need for a compact engine, and enables lubrication of the valve train regardless of the attitude of the engine.

According to the second aspect of the present invention, the crankshaft is arranged vertically, a driving gear is arranged at the lower end of the crankshaft, and a driven gear meshing with the driving gear is arranged at the camshaft. Since the gear chamber for housing is provided so that the second oil supply passage passes through the gear chamber on the way, lubrication of the gear is easy.

According to the third aspect of the present invention, since the oil inlet for detachably attaching the cap is disposed in the valve chamber, the valve chamber can be used as an oil pan.

According to the fourth aspect of the present invention, since the blow-by gas discharge path for communicating the crank chamber with the outside is arranged,
By reducing the amount of crankcase gas entering the valve chamber, the oil circulation capacity is reduced, but the amount of blow-by gas that comes into contact with the valve train can be reduced, and the durability of the lubricated portion improves.

[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 side view of the lawn mower.

FIG. 9 is an enlarged side view in which a part of the lawnmower is broken.

FIG. 10 is a sectional view of an engine portion of the lawnmower.

FIG. 11 is a sectional view of a general-purpose engine.

FIG. 12 is a longitudinal sectional view of an outboard motor mounted on a ship.

FIG. 13 is a longitudinal sectional view of an engine portion of the outboard motor.

FIG. 14 is a sectional view taken along the line XIV-XIV in FIG.

FIG. 15 is a top view power transmission diagram of the scooter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Engine main body 23 Crank chamber 33 Piston 33 Crank case 34 Cylinder 35 Connecting rod 36 Crankshaft 50 Camshaft 51 Driven gear 52 Drive gear 59 Output shaft 60 Intake passage 62 Combustion chamber 71 Check valve 72 Valve room 73 Valve system accommodation room 73a gear chamber 74 first oil supply path 75 second oil supply path E four-stroke engine

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F02F 1/24 F02F 1/24 F 7/00 7/00 LF term (reference) 3G013 AA03 AA04 AA16 AB01 AB02 AB03 BA04 BB12 BC11 BD26 BD28 BD47 CA01 3G015 AA03 AA04 AA16 AB01 AB02 AB03 BB01 BB06 BB10 BD10 BD11 BD24 BE03 BF05 BF08 BL09 CA01 CA06 CA07 DA10 EA26 3G024 AA47 AA50 AA69 BA23 BA24 DA01 DA03 FA04 EA14 DA16

Claims (4)

[Claims] 1. A check valve having a cylinder body in which a cylinder in which a piston reciprocates is formed, and a crankcase forming a crank chamber for accommodating a crankshaft together with the cylinder body. A first oil supply passage communicating the valve chamber and a valve operating system housing accommodating a valve operating system component that presses a check valve end; and a valve operating system. A four-stroke engine characterized in that a second oil supply passage communicating between a lower portion of the storage chamber and the crank chamber is arranged, and an outlet of the second oil supply passage faces an interlocking part of the crank chamber including a crankshaft, a connecting rod, and a piston. . 2. A check valve having a cylinder body in which a cylinder in which a piston reciprocates is formed, and a crankcase forming a crank chamber accommodating a crankshaft together with the cylinder body. A first oil supply passage communicating the valve chamber and a valve operating system housing accommodating a valve operating system component that presses a check valve end; and a valve operating system. A second oil supply passage communicating between the lower portion of the storage chamber and the crank chamber is disposed, and an outlet of the second oil supply passage faces a crank chamber interlocking component including a crank shaft, a connecting rod, and a piston, and the crank shaft is vertically disposed. A driving gear at the lower end of the crankshaft, a driven gear meshing with the driving gear on the camshaft, and a gear chamber for accommodating the driving gear and the driven gear are provided, and the second oil supply path is provided halfway. 4-cycle engine is characterized in that so as to pass through the cabin. 3. The four-stroke engine according to claim 1, wherein an oil inlet to which a cap is detachably attached is arranged in the valve chamber. 4. The four-stroke engine according to claim 1, further comprising a blow-by gas discharge passage communicating the crank chamber with the outside.