JPH0476210A - Head cover for overhead valve engine - Google Patents

Abstract

PURPOSE:To uniformize air-oil mist mixture and also to heighten a shielding effect on mechanical noise of movable valve parts through an effective lubricating ability for major parts by forming a cylinder head cover forming a valve system accomodating room approximately in a semi-spherical shape in an overhead valve engine. CONSTITUTION:Oil A in an oil pan 2 is sucked up by means of rotation of an oil slinger caused by rotation of a crank shaft 5 so as to lubricate the inside of a crank room S2 after the oil have turned into mist condition, and is also sent into a valve system accomodating room S1 through an oil supply route 38 by means of the pulsating pressure inside of the crank room S2 so as to recover it into the oil pan 2 through a return oil route 39 after having lubricated this accomodating room S1. In such lubricating structure, the valve system accomodating room S1 is formed as one united body with the upper surface of a cylinder head 100. This head cover 100 is formed approximately in a semi-spherical shape by means of a sheet metal drawing process and so on. Thereby, with regard to blowout of oil mist, reflection of oil mist 110 by means of the inside wall surface of the cylinder head cover can be made to be irregular reflection so that the mist can be supplied effectively to major parts needed to be lubricated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cylinder head cover applied to an overhead valve type engine.

[Prior Art] FIG. 5 shows a conventional example, in which an oil pan 2 is integrally formed in the lower opening of a crankcase 1, and a crank pin 5a and a piston 6 are connected to a connecting rod 7. The piston is slidably inserted into a cylinder 8 that projects laterally and horizontally from the side wall of the crankcase 1.

On the other hand, a gear 9 is fixed to the lower shaft 5b of the crankshaft 5. A camshaft 10 is supported in the crankcase 1 in parallel with the crankshaft 5 and on the opposite side of the cylinder 8, and a cam gear 10a formed integrally with the camshaft 10 meshes with the gear 9. It's forcing me. Further, cams 11 and 12 are integrally provided above the cam gear 10a. On the other hand, stems 16 and 17, which are integral with intake and exhaust valves 14 and 15, are disposed substantially horizontally penetrating the cylinder head 13, and the outer ends of these stems 16 and 17 are supported by rocker arms 18 and 19 in a seesaw shape. engage one end of the The other ends of the rocker arms 18 and 19 are engaged with the negative ends of bushing rods (not shown), and the other ends of the bushing rods are engaged with the respective cams 11 and 12. Valve 14.15 has spring retainer 24.25
The valve is biased toward the valve seat via valve springs 22 and 23 compressed and inserted between the cylinder heads 13, and the valve is closed when no external force is applied.

The cams 11 and 12, the bushing rods 20 and 21, the rocker arms 18 and 19, and the valves 14 and 15 constitute the main parts of an overhead valve (hereinafter abbreviated as OHV) mechanism. Note that a cylindrical member 13 is provided on the outer periphery of the cylinder head 13.
a to form a valve mechanism storage chamber S1.

Further, a flywheel 26 and a cooling fan 27 are fixed to the end of the upper shaft 5C of the crankshaft 5, and a recoil starter 28 is disposed opposite to the end of the upper shaft 5C. It is also equipped with a muffler 29, an auxiliary system 30, a fuel tank 31, etc., and a cutter plate (not shown) is fixed to the lower end of the lower shaft 5b. Further, the valve mechanism storage chamber S1 is formed by the head cover 60 and the cylinder head 13,
The head cover 60 is fixed to the cylinder head 13 with bolts or the like.

[Problems to be Solved by the Invention] However, the conventional OHV type head cover has the following problems.

(1) The lubricating oil introduced into the valve mechanism storage chamber S1 from the lubricating oil passage 38 is a mixture of lubricating oil mist and air, but since the top surface 60 of the head cover is flat, As shown, the mist scatters and there is a drawback that it is difficult to sufficiently lubricate the contact parts 19a between the valves 16 and 17 and the rocker arm, which are necessary lubrication parts of the valve mechanism of the OHV engine.

(2) Particularly when the engine is at a low temperature, the lubricating oil is not uniformly formed into a mist, so the rate of mist adhesion to the cylinder head canopy is high, and oil droplets must drip due to the aggregated mist.The lubricating oil is not supplied to the valve train parts. There was a problem in that seizures were likely to occur due to poor lubrication of the sliding parts.

(3) Furthermore, since the head cover itself is composed of a combination of flat parts, its function of blocking chatter noise caused by engine vibration and mechanical noise of valve train parts is insufficient.

An object of the present invention is to solve the problems of the conventional device, and to equalize the air-oil mist mixture in the valve mechanism storage chamber.
To provide an engine head cover that provides effective lubrication performance for parts requiring lubrication and sufficiently shields mechanical noise from valve operating parts.

[Means for Solving the Problems] The engine head cover according to the present invention has a substantially hemispherical shape, and the axis of the lubricating oil introduction hole with respect to the sliding part of the valve part of the OHV engine is aligned with the inner wall surface of the head cover. It is characterized in that the angle formed is within the range of approximately 15° to 60°.

[Function] Since the cylinder head cover is formed into a substantially hemispherical shape as described above, the sound emitting surface area of the head cover can be minimized, and high rigidity is obtained due to the hemispherical shape, thereby reducing chatter noise. Furthermore, the angle between the axis of the lubricating oil outlet hole and the wall surface of the cylinder head cover is configured to obtain the desired angle rather than the conventional right angle or parallel, making it possible to equalize the air-oil mist mixture in the valve mechanism housing chamber, which requires lubrication. Effective lubrication performance can be obtained for the parts.

[Example] An example of the present invention will be described below with reference to FIGS. 1 to 3.

Figure 1 is a longitudinal sectional view of the OHV type vertical engine, Figure 2
The figure is a partially sectional bottom view with the oil pan removed in FIG. 1, and FIG. 3 is a sectional view of a main part showing how oil mist is reflected.

In the above diagram, the component parts and their symbols are Herad cover 10
It is completely the same as that of the conventional example except for 0.

1 is a crankcase, 2 is an oil pan, 3 and 4 are bearings, 5 is a crankshaft, 5a is a crank pin, 6 is a piston, 7 is a connecting rod, 8 is a cylinder, 9 is a gear, 1
0 is the cam gear, 11.12 is the cam, 13 is the cylinder head, 14.15 is the valve, 16 and 17 are the same stem, 18
．． 19 is a rocker arm, 22.23 is a valve spring, 24°25 is a spring retainer, 26 is a flywheel, 27 is a cooling fan, 28 is a recoil starter, 2
9 is a muffler, 30 is an auxiliary machine, 31 is a fuel tank, SL is a valve mechanism chamber, and 100 is a head cover.

The head cover 100 is formed into a substantially hemispherical shape by sheet metal drawing or aluminum die casting, and is integrated with the upper surface of the cylinder head 100 to form a valve mechanism storage chamber S1.

In addition, as shown in FIG. 1, the angle θ between the axis of the lubricating oil outlet hole 38a and the wall surface of the head cover is 15@~60.
Configure it so that it is in the range of °.

Next, the engine lubrication structure in this embodiment will be explained.

The oil pan 2 contains a required oil (lubricating oil) A. The oil level upper limit Lu and oil level adjustment Ld of this oil A are each shown by a dashed line. On the other hand, a drive worm gear 2 is fixed on the camshaft 10 which is the lower limit of the gear 10a, and the worm gear 32 is engaged with a worm wheel 34 that is fixed on a drive shaft 33 disposed at a position orthogonal to the camshaft 10. It matches.

Further, a governor holder shaft 35 is arranged substantially parallel to the drive shaft 33, and a governor weight and an oil slinger 36 (not shown) are fixed to the shaft 35.

Part of the oil slinger 36 is the oil A in the oil pan 2.
Immersed inside. Also oil slinger one side cylinder 8
A return oil passage 39 is provided in the lower part of the cylinder head 13, passing through the interior thereof approximately parallel to the cylinder axis.The upstream opening end of the return oil passage 39 is located at the lowest part of the valve mechanism storage chamber S1. The downstream opening end faces and communicates with the lower part of the crank chamber S2, that is, the upper part of the oil pan 2.

Next, the behavior of the oil in the above-mentioned lubrication structure will be explained.

The rotation of the crankshaft 5 is transmitted through the path of crankshaft 5 → gear 9 → cam gear 10a → worm 32 → worm wheel 34 → (gear on shaft 33) → gear 37 → oil slinger 36, causing oil slinger 36 to rotate. . Due to the rotation of the oil slinger, the oil pan 2
The oil A in the crank chamber S2 is scraped up and the oil A is turned into a mist to lubricate the inside of the crank chamber S2, and these oil mists are fed to the oil supply path 3 by the pulsating pressure inside the crank chamber S2.
8 and is sent into the valve mechanism storage chamber S1. After lubricating the storage chamber, the oil passes through the return oil passage 39 at the bottom, passes through the pipe member 40 and the notch 41, and is recovered into the oil pan 2.

On the other hand, the parts in the valve mechanism storage chamber S□ that require lubrication include the contact portion 101a between the pivot bolt 101 and the rocker arm 19, the contact portion 19a between the valve 16.17 and the rocker arm 19, and the bushing rod 20. (21) and the contact portion 19b of the rocker arm 19. In the present invention, since the cylinder head cover is hemispherical with respect to the axis of the lubricating oil outlet hole 38, the oil is absorbed by the inner wall surface of the cylinder head cover against the ejection of oil mist. mist 110
Since the reflection becomes diffused reflection, an effective mist is supplied to areas that require lubrication. In the figure, the lubricating oil path is indicated by arrow H in the figure.

Although the above description has been made regarding the 0HV-vertical engine, the same applies to the 0HV-horizontal engine.

[Effects of the Invention] In the present invention, since the engine head cover has a substantially hemispherical shape, the sound radiation area of the head cover can be minimized, and due to this shape, chatter noise etc. can be reduced, and mechanical noise from valve train parts can be effectively reduced. The angle between the axis of the lubricating oil outlet hole and the inner wall surface of the head cover is set in the range of 15° to 60° to prevent oil mist inside the valve mechanism storage chamber and to improve lubrication of the valve mechanism storage chamber. When the oil mist collides with the head cover, the oil mist is reflected in a diffused manner, so the mist can be effectively supplied to the parts that require lubrication.This makes the oil mist concentration in the valve mechanism storage chamber uniform, reducing wear on important parts and reducing the risk of wear on the rocker arm. Sound can be reduced.

[Brief explanation of the drawing]

Figures 1 to 3 relate to the present invention; Figure 1 is a longitudinal sectional view of an OHV vertical engine, Figure 2 is a partially sectional bottom view with the oil pan removed in Figure 1, and Figure 3 is a vertical sectional view of the OHV vertical engine. 4 is a sectional view of a main part showing an oil mist reflection situation, FIGS. 4 and 5 are a conventional example, FIG. 4 is a view corresponding to FIG. 3, and FIG. 5 is a longitudinal sectional view of a HV vertical engine. 38... Oil supply path, 38a... Lubricating oil outlet hole,
100...Head cover, θ is the angle between the axis of the lubricating oil outlet hole and the inner wall surface of the head cover. Mixed 1st slide, middle J finished i-

Claims (3)

[Claims] (1) An oil pan is provided at the bottom of the engine, and the oil in the oil pan is sent to the valve mechanism storage chamber in the cylinder head through a supply passage, and from the storage chamber to the oil pan through an oil return passage. What is claimed is: 1. An overhead valve engine equipped with a lubrication mechanism that returns lubrication to the inside, wherein the cylinder head cover forming the valve mechanism storage chamber has a substantially hemispherical shape. (2) The overhead valve engine according to claim 1, wherein the axis of the lubricating oil outlet hole from the oil supply passage to the valve mechanism storage chamber and the wall surface of the cylinder head cover form a predetermined angle. (3) The overhead valve engine according to claim 2, wherein the predetermined angle is approximately within a range of 15° to 60°.