JPH0828234A - Lubrication device of valve system cam for longitudinal overhead cam type engine - Google Patents

Abstract

PURPOSE:To prevent oil from blowing back from oil return holes of a vertical overhead cam type engine. CONSTITUTION:Oil storage parts 3 and an return holes 7 are provided in the upper face 2 of the cylinder head of a longitudinal overhead cam type engine E. Eaves 10 for shelter are faced to the oil return holes 7 in such a state as covering over them. Oil guide grooves 12 are recessedly provided in the upper face 2 of the cylinder head and the oil storage parts 3 are communicated to the oil return holes 7 by the oil guide grooves 12. Therefore, when oil is blown back from the oil return holes 7 by pressure change of a crank chamber, etc., oil invasion in a head cover chamber 4 is prevented by the eaves 10 for shelter. Or, oil to be supplied to the oil storage parts 3 is guided to the oil return holes 7 gradually by the oil guide grooves 12 so that oil storage quantity can be appropriately regulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating cam lubricating device for a vertical overhead cam engine, which prevents the oil from being blown back to the head cover chamber, and also ensures that the amount of lubricating oil in the valve operating cam is appropriate. Provide something that can be adjusted.

[0002]

BACKGROUND OF THE INVENTION The basic structure of a lubricating mechanism for a valve operating cam of a vertical overhead cam engine, which is the subject of the present invention, has a basic structure as shown in FIG. 4 and FIG. The valve camshaft 5 is arranged laterally in the chamber 4, and the valve cam 6 of the valve camshaft 5 can be used to open and close the open / close valve 8.
An oil reservoir 3 is recessed in the upper surface 2 of the cylinder head 1, the valve operating cam 6 faces the oil reservoir 3 from above, and an oil return hole 7 is opened in the upper surface of the cylinder head 1. The head cover chamber 4 is communicated with the crank chamber via the return hole 7 to lubricate the valve operating cam 6 with the oil stored in the oil storage portion 3 and to return the oil from the oil return hole 7 to the crank chamber. It is of the form

[0003]

2. Description of the Related Art As a conventional technique of this type, as shown in FIGS. 5 and 6, a two-cylinder vertical overhead cam type engine E is used.
A horizontally long oil storage groove 3 is formed on the upper surface 2 of the cylinder head along the valve operating cam shaft 5, and oil return holes 7 are formed at four corners of the upper surface 2 of the cylinder head along side walls 11 of the cylinder head 1. However, there is one in which a breather device 30 is attached to the upper wall of the head cover 14.

In the above-mentioned prior art, the rotating valve cam 6 is used.
Is immersed in the oil stored in the oil storage groove 3 to be lubricated, while the oil supplied to the oil storage groove 3 by the lubrication pump overflows from the storage groove 3 through the oil return hole 7 through the crank chamber to the oil pan. Returned to.

[0005]

Generally, in a single-cylinder engine or a two-cylinder engine in which explosions are set at equal intervals, the pressure in the crank chamber greatly fluctuates as the piston moves up and down.

Therefore, in the above-mentioned prior art, when the crank chamber is pressurized, the crank chamber becomes a positive pressure with respect to the head cover chamber 4, so that the oil to be returned to the crank chamber from the oil return hole 7 is reversed. However, there is a risk of being blown back into the head cover chamber 4. Further, the oil overflowing from the oil storage groove 3 may flow on the upper surface 2 of the cylinder head, and a large amount of oil may flow into the oil return hole 7 all at once. In this case, a larger amount of oil is blown back. Become.

When the oil is blown back, the head cover chamber 4 is excessively filled with oil mist, so that the oil flows out from the breather device 30, resulting in an excessive oil consumption and polluting the atmosphere. Alternatively, in the type in which the breather device 30 is returned to the primary chamber of the air cleaner via the return path, oil may be attached to the filter element of the air cleaner and the element may be clogged. An object of the present invention is to prevent blowback of oil from an oil return hole of a vertical overhead cam engine.

[0008]

Means for achieving the above object will be described below with reference to FIGS. 1 to 4 showing an embodiment. That is, according to the present invention, in the lubricating device for the valve operating cam of the vertical overhead cam engine having the basic structure, the oil return hole 7 is made to face the shielding eaves 10 from above, and the upper surface 2 of the cylinder head 1 is covered. The oil guide groove 12 is formed in the oil guide groove 12, and the oil reservoir 3 is communicated with the oil return hole 7 through the oil guide groove 12.

The vertical overhead cam type engine E includes both a method of directly opening / closing the opening / closing valve 8 by the valve operating cam 6 and a method of indirectly driving the opening / closing valve 8 via a rocker arm. .

[0010]

When the oil is blown back from the oil return hole 7 due to the pressure fluctuation in the crank chamber, the oil return hole 7
The shielding eaves 10 covering the head cover 4 prevent the head cover chamber 4 from entering. That is, the oil adheres to the shielding eaves 10 and then flows down to the oil returning hole 7 again, or collides with the shielding eaves 10 and is directly splashed back to the oil returning hole 7. Therefore, the head cover chamber 4 is not excessively filled with oil mist, and even if a breather device is provided in the head cover chamber, there is no possibility that oil will flow out from the breather device.

In addition, the oil reservoir 3 is connected to the oil guide groove 12
Since it is communicated with the oil return hole 7, the oil supplied to the oil storage portion 3 is smoothly returned to the oil return hole 7 through the oil guide groove 12 successively, so that the amount of stored oil can be properly adjusted. Therefore, unlike the prior art,
A large amount of oil does not overflow from the oil storage groove 3 to the oil return hole 7 all at once, and it is possible to smoothly prevent a large amount of oil from being blown back from the oil return hole 7.

[0012]

【The invention's effect】

(1) When the oil is blown back from the oil return hole due to the pressure fluctuation in the crank chamber, the shielding eaves can prevent the oil from entering the head cover chamber, so the head cover chamber is not overfilled with oil mist. . Therefore, even when the breather device is provided in the head cover chamber, there is no fear that oil will flow out from the breather device, the oil consumption amount can be kept small, and air pollution and clogging of the air cleaner can be prevented.

(2) The oil supplied to the oil reservoir is
The oil guide groove guides the oil smoothly to the oil return hole one by one, so the amount of oil stored is adjusted properly, and the valve operating cam is sufficiently lubricated, while the oil blowback in (1) above is more efficient. It can be prevented well.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a main part of a lubricating device for a valve operating cam of a vertical overhead cam engine, FIG. 2 is a vertical sectional side view of an oil return hole of the lubricating device, and FIG. 3 is a vertical sectional front view of the lubricating device. Figure 4
FIG. 3 is a vertical cross-sectional side view of the intake / exhaust valve of the lubrication device.

As shown in FIGS. 1 to 4, a side wall 11 having an upward spread shape is erected on the outer peripheral portion of the cylinder head 1 of the vertical two-cylinder engine E, and a head cover 14 is attached to the upper side of the cylinder head side wall 11 to attach the head cover The rocker arm shaft 13 is arranged on the upper side of the chamber 4, and the valve operating cam shafts 5 are arranged in parallel on the lower side thereof in the left-right direction.
It is interlocked with a crankshaft (not shown) via 0.

The rocker arm 1 is attached to the rocker arm shaft 13 described above.
5, the valve cam 6 of the valve cam shaft 5 is interlocked with the input part of the rocker arm 15 and the output part of the rocker arm 15 is interlocked with the intake / exhaust valve 8, respectively. The intake / exhaust valve 8 can be opened and closed via the rocker arm 15 by the rotation of 6.

As shown in FIGS. 1 to 4, one oil storage groove 3 is formed in the center of the upper surface 2 of the cylinder head 1 so as to extend in the left-right direction with an arcuate cross section. This oil storage groove 3
The valve operating cam 6 of the valve operating cam shaft 5 is exposed from above, and the rotating valve operating cam 6 is immersed in the stored oil in the oil storage groove 3.

As shown in FIG. 3, a shaft oil passage 21 is provided so as to extend in the axial direction of the valve camshaft 5, and a lubricating pump 16 is provided in the vertical overhead cam engine E. The suction side of the lubricating pump 16 is provided. The oil passage 17a is routed through the oil strainer 18 to the oil pan 1
9, the discharge side oil passage 17b of the lubricating pump 16 is connected to the oil storage groove 3 and the shaft oil passage 21 of the valve operating camshaft 5.

As shown in FIGS. 1 and 2, substantially rectangular oil return holes 7 are formed at the four corners of the upper surface 2 of the cylinder head 1, and the oil return holes 7 are formed along the cylinder head side wall 11. . The head cover chamber 4 is communicated with the crank chamber (not shown) and the oil pan 19 through the oil return hole 7 to lubricate the valve operating cam 6 with the oil stored in the oil storage groove 3 and to return the oil. The oil is returned from the hole 7 to the oil pan 19 via the crank chamber.

As shown in FIGS. 1 and 2, a substantially rectangular shielding eaves 10 is laterally projected from the cylinder head side wall 11 and the oil evacuation hole 7 is made to face the shielding eaves 10 from above. . The shielding eaves 10 may be formed separately from the cylinder head side wall and fixed, but if formed integrally with the cylinder head side wall 11 as in this embodiment, the number of parts and the number of assembling steps are small. The structure is simple. A total of four oil guide grooves 12 are formed in a U-shaped cross section, one pair on the left and right sides of the cylinder head upper surface 2, and the oil reservoirs 3 communicate with the oil return holes 7 at the four corners by the oil guide grooves 12. To do.

As shown in FIGS. 1, 3 and 4, a breather device 30 is provided on the upper wall 14a of the head cover 14, a breather port 31 of the breather device 30 is opened in the head cover chamber 4, and the breather port 31 leads. The valve 32 is exposed and the breather outlet 33 is directly communicated with the outside air, or is communicated with a primary chamber of an air cleaner (not shown) through a return passage.

Therefore, the function of the lubricating mechanism for the valve operating cam of the vertical overhead cam engine of this embodiment will be described. (1) When the oil is about to be blown back from the oil return hole 7 due to the pressure fluctuation in the crank chamber due to the ascent and descent of the piston, this oil is transferred to the head cover chamber 4 by the shielding eaves 10 that closely covers the oil return hole 7. Are prevented from entering. That is, the oil adheres to the lower surface of the shielding eaves 10 and then flows down along the cylinder head side wall 11 toward the oil returning hole 7 again, or collides with the shielding eaves 10 and directly reaches the oil returning hole 7 directly. It is bounced back by. Therefore, the head cover chamber 4 is not excessively filled with oil mist, and the risk of oil flowing out from the breather device 30 attached to the head cover 14 can be eliminated, so that the oil consumption amount can be kept small and air pollution and air pollution can be prevented. Eliminates clogging of the air cleaner.

(2) Since the oil storage groove 3 is communicated with the oil return hole 7 by the four oil guide grooves 12, the oil supplied to the oil storage groove 3 is successively passed through the oil guide groove 12 and the head cover chamber. It is smoothly returned to the oil return holes 7 at the four corners of No. 4, and the amount of oil stored can be adjusted appropriately. For this reason, it is possible to more efficiently prevent the blowback of the oil in (1) while sufficiently lubricating the valve operating cam 6.

The present invention can also be applied to a vertical overhead cam engine in which the intake / exhaust valve 8 is directly opened / closed by the valve operating cam 6. Further, instead of forming the oil storage portion 3 for lubricating the valve operating cams 6 as one storage groove as in the above embodiment, for example, an oil reservoir is individually provided on the lower surface facing each valve operating cam 6. You may make it concave.
Moreover, the present invention can be applied to both spark ignition engines and diesel engines.

[Brief description of drawings]

FIG. 1 is a plan view of a main part of a lubrication device for a valve operating cam of a vertical overhead cam engine.

FIG. 2 is a vertical sectional side view around an oil return hole of the lubricating device.

FIG. 3 is a vertical sectional front view of the lubricating device.

FIG. 4 is a vertical sectional side view of the vicinity of the intake / exhaust valve of the lubricating device.

FIG. 5 is a view equivalent to FIG. 1 showing the prior art.

FIG. 6 is a view corresponding to FIG. 2 showing the conventional technique.

[Explanation of symbols]

1 ... Cylinder head, 2 ... Cylinder head upper surface, 3 ...
Oil storage part (oil storage groove), 4 ... Head cover chamber,
5 ... Valve cam shaft, 6 ... Valve cam, 7 ... Oil return hole,
8 ... Open / close valve (intake / exhaust valve), 10 ... Shielding eaves, 12 ... Oil guide groove, E ... Vertical overhead cam engine.

Claims (1)

[Claims] 1. A head cover chamber (4) for a vertical engine (E).
The valve camshaft (5) is placed sideways on the valve camshaft (5)
The opening / closing valve (8) can be opened / closed by the valve operating cam (6), and the oil storage portion (3) is recessed in the upper surface (2) of the cylinder head (1). The valve operating cam (6) is faced to 3) from above, an oil return hole (7) is opened in the upper surface (2) of the cylinder head (1), and the head cover chamber (7) is opened through this oil return hole (7). 4)
Of the vertical type which communicates with the crank chamber, lubricates the valve operating cam (6) with the oil stored in the oil storage part (3), and returns the oil from the oil return hole (7) to the crank chamber. In a lubricating device for a valve operating cam of an overhead cam engine, the oil return hole (7) is made to face the shielding eaves (10) from above, and the oil guide is provided on the upper surface (2) of the cylinder head (1). The groove (12) is recessed, and the oil reservoir (3) is in the oil guide groove.
A lubricating device for a valve operating cam of a vertical overhead cam type engine, which is communicated with an oil return hole (7) at (12).