JPH0218254Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to the structure of a refueling device for a rocker arm chamber of a vertical shaft type engine.

[Conventional technology] In overhead valve type (OHV including OHC) engines,
An intake valve and an exhaust valve are arranged directly above the combustion chamber (in the direction of the cylinder axis), and a rocker arm for driving these valves is attached to the upper part of the cylinder head (in the direction of the cylinder axis).

Therefore, a rocker arm chamber in which a valve operating mechanism such as a rocker arm is housed is formed above the cylinder head.

This rocker arm chamber is usually formed in a head cover that covers moving parts such as the rocker arm's swing bearing, the contact area between the rocker arm and the valve stem, and the valve guide that slides and guides the valve stem.

These moving points must be lubricated, and for this purpose a lubrication device for the rocker arm chamber is provided.

Conventionally, this type of rocker arm chamber oil supply system has a structure in which passages (usually two locations) are formed between the crank chamber and the rocker arm chamber, and the oil in the crank chamber is circulated to the rocker arm chamber. It has been proposed in publications such as 1973-38736.

[Technical problem that the invention attempts to solve]

However, in an overhead valve type engine, the Rotsuker arm chamber is separated from the crank chamber, so the conventional oil supply method of simply providing an oil passage and scooping up the oil in the crank chamber and scattering it is not possible because the oil circulates smoothly and reliably. It was difficult to lubricate the surface.

In particular, in a vertical shaft type engine in which the crankshaft is arranged vertically, the oil supply passage is formed in the upper part of the cylinder, and the oil return passage is formed in the lower part of the cylinder. In some cases, the return was insufficient, and oil filled the rocker arm chamber during operation, causing oil to enter the combustion chamber through the valve guide, resulting in increased oil consumption or white smoke in the exhaust gas.

This tendency becomes even more noticeable when the engine leans forward and the cylinder head position drops.

At the same time, in the vertical shaft type engine, the upper bearing of the crankshaft is located at a position considerably higher than the oil level in the crank chamber, so simply scooping up and scattering the oil may tend to lack lubrication of the bearing. It was hot.

〔the purpose〕

The present invention has been made in view of such conventional technology, and in particular, by ensuring the return of oil from the Rocker arm chamber to the crank chamber, the oil circulation to the Rocker arm chamber is smoothed.
It is an object of the present invention to provide a lubricating device for a rocker arm chamber of a vertical shaft type engine, which can perform reliable lubrication and can also reliably lubricate the upper bearing of a crankshaft.

[Means for solving problems]

The present invention provides an oil supply system for a rocker arm chamber of a vertical shaft type engine in which oil in the crank chamber is circulated to the rocker arm chamber through an oil supply passage and a return passage, and the oil supply passage is formed by penetrating the upper part of the cylinder and the cylinder head. The return passage is formed through the cylinder and the lower portion of the cylinder head, and a mating surface of the return passage between the cylinder and the cylinder head opens when the pressure in the rocker arm chamber is equal to or higher than the pressure in the crank chamber. The above object is achieved by providing a check valve for valving and further opening the entrance of the oil feed passage between the upper bearing of the crankshaft and the oil seal.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a vertical sectional view of a main part of a vertical shaft type engine equipped with a rocker arm chamber oil supply device according to an embodiment of the present invention.

In FIG. 1, a crankshaft 3 is vertically supported in a crank case 2 forming a crank chamber 1, and a horizontal cylinder 4 is provided on the side of the crank chamber 1. The fitted piston 5 and the crankshaft 3 are connected by a connecting rod 6.

A cylinder head 7 is joined to the top surface of the cylinder 4, and a combustion chamber 8 is formed between the top surface of the piston 5 and the cylinder head 7.

An intake valve 10 and an exhaust valve 11 are fitted into the valve guides 9, 9 provided on the cylinder head 7, and these intake and exhaust valves 10, 11 are located above the cylinder head 7 (in the direction of the cylinder axis, as shown in the figure). In this case, the Rotsuker arm 12,1 is pivoted on the left side)
2, it is driven to open and close at a predetermined timing.

The rocker arms 12, 12 are housed in a rocker arm chamber 14 formed by joining a head cover 13 to the upper side (left side in the case shown) of the cylinder head 7.

The rocker arms 12, 12 may be provided with a tappet pushrod mechanism (not shown) that is reciprocated by a camshaft (not shown) that is pivotally supported within the crank chamber 1, or with a tappet push rod mechanism (not shown) that is pivotally supported within the rocker arm chamber 14. It is oscillatedly driven by a camshaft (not shown) that is rotatably driven by a transmission means such as a chain or a gear train provided between the crankshaft 3 and the crankshaft 3.

The crankshaft 3 is supported by a bearing 15 at the upper part of the crankcase 2, and an oil seal 16 is attached to the outside of the bearing 15.

Further, the lower part of the crankshaft 3 is supported by a bearing part 18 provided on a crank case cover (oil pan) 17 forming the bottom part of the crank chamber 1, and its downward protruding part serves as an output shaft.

In the illustrated engine, a cooling fan 19 that also serves as a flywheel is fixed to an upwardly protruding portion of the crankshaft 3, and a recoil starter 21 is attached to a fan cover 20 that covers the cooling fan 19.

Lubricating oil 22 at a predetermined level is provided inside the crankcase cover 17 (at the bottom of the crank chamber 1).
The oil 22 is collected in an oil splatter 23 rotated by the crankshaft 3, and the oil 22 is scraped up and scattered to lubricate desired locations such as the big end of the crank, the piston 5, and the bearing 15. .

Next, the oil supply system for the rocker arm chamber 14 will be explained.

In FIG. 1, an oil feed passage 24 and a return passage 25 are formed in the cylinder 4 and the cylinder head 7.

These passages 24 and 25 are for circulating the oil 22 in the crank chamber 1 to the rocker arm chamber 14, and the oil feed passage 24 that sends the oil 22 to the rocker arm chamber 14 connects the upper part of the cylinder 4 and cylinder head 7. The oil 2 is formed through the rocker arm chamber 14 to the crank chamber 1.
A return passage 25 for returning the cylinder 2 is formed through the cylinder 4 and the lower part of the cylinder head 7.

The return passage 25 is provided with a check valve 26 that opens when the pressure in the rocker arm chamber 14 exceeds the pressure in the crank chamber 1 and allows oil to flow toward the crank chamber 1.

In the illustrated example, a valve chamber is formed by enlarging the cross-sectional area of the portion of the return passage 25 that opens to the meeting surface of the cylinder 4 and the cylinder head 7, and the check valve 26 is located within this valve chamber. It is provided.

The inlet 36 of the oil feed passage 24 opens between the upper bearing 15 of the crankshaft 3 and the oil seal 16, and is also opened by the oil 22 fed from the crank chamber 1 into the rocker arm chamber 14. It is configured to lubricate the bearing 15.

2 to 4 show structural examples of the check valve 26, respectively.

The check valve 26 shown in FIG. 2 is inserted into and held in an opening of a head gasket 27 attached to the mating surface of the cylinder 4 and the cylinder head 7, and moves to the left when the crank chamber 1 is under positive pressure. The return passage 25 is closed by contacting the cylinder head 7 side, and the crank chamber 1
When the pressure is negative, the cylinder head 7 moves to the right.
The return passage 25 is operated to communicate with the return passage 25 through a through hole 28 formed in the head gasket 27.

The check valve 26 in FIG. 3 is formed of an elastically deformable leaf spring provided on the end face of the return passage 25 on the side of the cylinder head 7, and opens as shown in the figure when the crank chamber 1 is under negative pressure. The structure is designed to communicate with each other.

Note that a through hole 29 is formed in the head gasket 27 at a position corresponding to the return passage 25.

The check valve 26 in FIG. 4 is a valve holding member 3 fixed to the end of the return passage 25 on the cylinder 4 side by press fitting or the like.
0 and is held there.

An oil passage hole is formed in a notch 31 formed around the valve holding member 30, and an opening 32 is formed in a corresponding portion of the head gasket 27.

Therefore, the check valve 26 in this case also moves to the left when the crank chamber 1 is under positive pressure, contacts the cylinder head 7, closes the return passage 25, and closes the return passage 25.
When the pressure is negative, it moves to the right and separates from the cylinder head 7 and operates to communicate with the return passage 25.

Returning to FIG. 1, the Rocker arm chamber 14
A breather 33 is provided to separate oil mist (a mixture of oil and air) into oil and air and to guide the air to the outside.

The air discharged from the breather 33 is led to, for example, an intake pipe or an air cleaner, mixed with intake air, and supplied to the engine.

Lubrication within the rocker arm chamber 14 is performed as follows.

When the piston 5 descends (close to bottom dead center) and the crank chamber 1 becomes positive pressure, the oil splatter 23
The oil mist (mixture of oil and air) in the crank chamber that has been stirred up and scattered is introduced into the oil feed passage 24 through the inlet 36 opened between the bearing 15 and the oil seal 16, and 24 into the rocker arm chamber 14.

While the crank chamber 1 is under positive pressure, the return passage 25 is blocked by the check valve 26, so that the oil 22 is kept until the rocker arm chamber 14 reaches a predetermined pressure (the pressure inside the crank chamber 1). The rocker arm chamber 14 is filled.

The oil mist sent into the Rocker arm chamber 14 is separated into oil and air by the Rocker arm chamber 14 and the breather 33. , 12 and the intake/exhaust valves 10, 11 or cams, and the sliding parts between the intake/exhaust valves 10, 11 and the valve guides 9, 9.

On the other hand, air is led out through the breather 33 and sent to an intake pipe, an air cleaner, or the like.

When the piston 5 rises and the crank chamber 1 becomes negative pressure, the check valve 26 of the return passage 25 opens, and the oil accumulated in the lower part of the rocker arm chamber 14 passes through the return passage 25 and returns to the crank chamber 1 due to the negative pressure.
quickly and reliably.

According to the embodiment described above, the check valve 2 allows the oil to flow toward the crank chamber 1 into the return passage 25.
6 is provided, when the crank chamber 1 has positive pressure, the return passage 25 can be closed and oil can be sent from the oil supply passage 24 to the rocker arm chamber 14 until it reaches a predetermined pressure, and when the crank chamber 1 is under negative pressure, the return passage 25 can be closed. The oil can be returned to the crank chamber 1 by opening the passage 25 and using the suction force of the negative pressure, and the oil can be returned reliably.

In this way, the pressure fluctuations in the crank chamber 1 can be used to reliably feed and return oil with different phases, so the rocker arm chamber 1
It is possible to smoothly circulate an appropriate amount of oil to 4, and the lubrication function can be improved without increasing oil consumption.

Furthermore, since the inlet 36 of the oil feed passage 24 is opened between the upper bearing 15 of the crankshaft 3 and the oil seal 16, the oil 22 circulated into the rocker arm chamber 14 can also be used for the bearing 15 and the oil seal 16. Can lubricate the vicinity.

In particular, in a vertical shaft type engine, since the upper bearing 15 of the crankshaft 3 is located considerably above the oil level at the bottom of the crank chamber 1, it is relatively difficult to lubricate it. According to the above, since the oil 22 sent to the rocker arm chamber 14 passes through the inside of the bearing 15, it becomes possible to easily and reliably lubricate the inside of the bearing 15 and the bearing surface of the crankshaft 3. Ta.

Furthermore, since the check valve 26 in the return passage 25 is located at the meeting surface between the cylinder 4 and the cylinder head 7, the check valve 26 can be easily installed, maintained, and inspected by simply removing the cylinder head 7. be able to.

In the above embodiment, one oil supply passage 24 and one return passage 25 were provided, but these passages 2
A plurality of numbers 4 and 25 may be provided if necessary.

[Effect of idea]

As is clear from the above description, according to the present invention, in the oil supply device for the rocker arm chamber of a vertical shaft engine in which oil in the crank chamber is circulated to the rocker arm chamber through the oil feed passage and the return passage, the oil feed passage is connected to the cylinder and the oil return passage. The return passage is formed through the upper portion of the cylinder head, and the return passage is formed through the cylinder and the lower portion of the cylinder head. A check valve that opens when the pressure exceeds the pressure in the crank chamber is provided, and the entrance of the oil feed passage is opened between the upper bearing of the crankshaft and the oil seal, so that the locker arm chamber is closed. By ensuring the return of oil from the engine to the crank chamber, smooth oil circulation to the Rocker arm chamber can be achieved, and
A Rocker arm for a vertical shaft engine in which the above-mentioned check valve can be easily installed or maintained and inspected, and furthermore, the upper bearing of the crankshaft can be easily and reliably lubricated by using oil circulated to the Rocker arm chamber. A chamber refueling device is obtained.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing the main parts of a vertical shaft type engine equipped with a rocker arm chamber oil supply device according to an embodiment of the present invention, and FIGS.
FIG. 3 is a partial longitudinal cross-sectional view showing various structural examples of the check valve shown in the figure. 1...crank chamber, 3...crankshaft, 4...
Cylinder, 7... Cylinder head, 12... Rocker arm, 14... Rocker arm chamber, 15... Bearing, 16... Oil seal, 22... Oil, 24
...Oil supply passage, 25...Return passage, 26...Check valve, 3
6... Entrance of the oil supply passage.

Claims (1)

[Scope of utility model registration request] The oil 22 in the crank chamber 1 is passed through the oil supply passage 24 and the return passage 25 to the rocker arm chamber 14.
In the oil supply system for the rocker arm chamber of a vertical shaft type engine, the oil supply passage 24 is formed passing through the upper part of the cylinder 4 and the cylinder head 7, and the return passage 25 is formed under the cylinder 4 and the cylinder head 7. A check valve that is formed through the side portion and opens when the pressure in the rocker arm chamber 14 exceeds the pressure in the crank chamber 1 is provided at the mating surface of the cylinder 4 and the cylinder head 7 of the return passage 25. 26, and the inlet 36 of the oil feed passage 24 is opened between the upper bearing 15 of the crankshaft 3 and the oil seal 16.