JPS6251709A - Lubricating oil feeding device for dohc engine - Google Patents

Abstract

PURPOSE:To enable the feed of quantities of lubricating oil to a bearing part on the exhaust side, by a method wherein an oil passage, being closed passage, is provided for being communicated with a port, through which oil is fed through the suction side and the exhaust side of a cylinder head to a cam shaft bearing part, and the oil introducing port of the oil passage is formed on the suction side. CONSTITUTION:Bearing parts 4a and 4b for cam shafts on the suction side and the exhaust side, respectively, are disposed to a cylinder head 1 one on each one along axes 3a and 3b. In this case, oil passages 10a and 10b are formed in the side walls on the suction and exhaust sides, respectively, of the cylinder head 1 throughout about the overall length of the side wall. Further, oil passages, through which the oil passages 10a and 10b are communicated with oil feed pots 8a and 8b of the bearing parts 4a and 4b, respectively, are provided. The both end parts of the oil passages 10 and 10b are intercommunicated through two oil passages 12 and 13 formed in the front and the rear end of the cylinder head 1 to form a closed passage. An oil introduction port 14 is formed about in the central part of the oil passage 10a on the suction side to feed lubricating oil to the oil passage 10b on the exhaust side.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a lubricating oil supply device for a DOHC engine, and particularly to a cam for a DOHC engine with a so-called 4-pulp configuration, which has two intake valves and two exhaust valves per cylinder. The present invention relates to a lubricant supply structure for a shaft bearing.

(Prior art) A DOHC engine has a camshaft for the intake valve and a camshaft for the exhaust valve arranged above the cylinder head, and these two camshafts directly drive the intake pulp and the exhaust valve, respectively. , it is possible to combine the V-shaped valve arrangement with high filling efficiency and the center plug method, and the operating weight of the valve train is small, so the valve operation timing is accurate even during high-speed rotation. It has traditionally been used as an output engine. Among such OHC engines, there is a so-called 4-valve configuration in which two intake valves and two exhaust valves are provided per cylinder, as described in Japanese Utility Model Application No. 58-56104, for example. Since the weight per unit can be further reduced and the valve area per cylinder can be increased, the output can be further improved, resulting in an ideal configuration.

By the way, the so-called 4-valve configuration DOH as mentioned above
In the case of the C engine, in order to make the engine more compact, the overall length of the cylinder head is shortened, and the camshaft bearings that rotatably support the camshaft are installed at each cylinder for each cylinder. It is installed in the middle position between two valves. An oil passage extending along the extension direction of the camshaft is provided in both side walls of the cylinder head, and a communication passage is provided to communicate this oil passage with an oil filler port formed on the bearing surface of the camshaft bearing. lubricating oil is supplied to each camshaft bearing.

However, due to the compactness of the engine and the relationship with the valve packet, the camshaft bearing part has a narrow part, and this narrow part makes it impossible to secure an appropriate amount of lubricating oil, causing oil film to run out. may occur. Furthermore, the exhaust side of the engine is at a higher temperature than the intake side, and therefore the lubricating oil supplied to the camshaft bearing on the exhaust side is likely to deteriorate. Therefore, if equal amounts of lubricating oil are supplied to the camshaft bearings on the intake side and exhaust side, even if the amount of lubricating oil is sufficient on the intake side, it is likely to be insufficient on the exhaust side. There is a risk of For this reason, it is desirable to be able to supply a larger amount of lubricating oil to the camshaft bearing on the exhaust side than on the intake side, but in conventional engines of this type, such considerations have not been specifically implemented. No concise structure has been proposed for this purpose.

(Object of the Invention) The present invention has been made in view of the above circumstances, and has an extremely economical structure, but is capable of supplying a larger amount of lubricating oil to the camshaft bearing on the exhaust side than on the intake side.
The purpose of the present invention is to provide a lubricating oil supply device for an HC engine.

(Structure of the Invention) The present invention is characterized in that an oil passage is provided in the cylinder head, and the intake side and exhaust side of the cylinder head are bent and extended, and the oil supply port for each camshaft bearing portion is connected to the closed passage. The oil inlet of the oil passage is provided on the intake side, and the lubricating oil is introduced from the oil inlet and flows through the oil passage to the exhaust side.

(Effects of the Invention) According to the above configuration, due to the influence of the dynamic pressure of the lubricating oil introduced into the oil passage from the oil inlet, the camshaft bearing located far from the oil inlet is Since the amount of oil discharged increases, a larger amount of lubricating oil can be supplied to the camshaft bearing on the exhaust side.

(Example) Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a plan view of a cylinder head of a DOHC engine to which the present invention is applied, and FIGS. 2 and 3 are cross-sectional views taken along the lines ■--■ and III--III in FIG. 1, respectively. Note that FIG. 1 shows the body with the camshaft removed. 4 and 5 are cross-sectional views of the camshaft bearing section taken along the TV--TV line and the V--■ line in FIG. 3.

A cylinder head 1 for a 4-cylinder, 4-valve DOHC engine includes an intake camshaft 2a and an exhaust camshaft 2b (axis 3a in FIG. 1).

3b is shown) are arranged along the axes 3a, 3b, one for each cylinder, i.e. four on both the intake and exhaust sides. . Intake valves and exhaust valves (not shown) each driven by the camshafts 2a and 2b are arranged in a V-shape with a predetermined included angle θ (see FIG. 3). Each valve is driven through a hydraulic lash adjuster (not shown) that can automatically adjust valve lash to zero to reduce noise and eliminate the need for valve lash adjustment work. A packet support portion 6 having holes 5 for guiding the packet of the lash adjuster is provided integrally with the vessel wall of the cylinder head 1. The camshaft bearing parts 4a and 4b are the shafts of the camshafts as seen in FIG.
a, 3b.

The center portions of the bearing surfaces 7a, 7b of the camshaft bearings 4a, 4b on the side of the cylinder rad 1 are provided at an intermediate position of the packet support portion 6, and As is clear from the figure, the bearing surface 7a is made narrow in order to avoid interference with the lash adjuster packet.

Refueling ports 8a and 8b are opened on 7b. 9a, 9b
is the bearing cap.

Oil passages 10a and 10b are formed in the intake side and exhaust side walls of the cylinder head 1 over substantially the entire length of the side walls. As shown in FIG. 3, an oil passage 11a is provided that communicates between the oil passage 10a on the intake side and the oil filler port 8a of the camshaft bearing 4a, and similarly, an oil passage 11a is provided that communicates with the oil passage 10b on the exhaust side. An oil passage 11b is provided that communicates with the oil supply port 8b of the camshaft bearing portion 4b. Oil passage 10a, 1
Both ends of 0b are communicated by two oil passages 12 and 13 formed at the front and rear ends of the cylinder head 1 and extending in a direction perpendicular to the direction of extension of the camshafts 2a and 2b. The passages 10a, 12.1 (lb and 13) form a closed path as shown in FIG. , an oil inlet 1 as shown in FIG. 2 is located approximately in the center of the oil passage 10a on the intake side.
4 is provided, and the lubricating oil fed from the lower cylinder block (not shown) to the oil inlet 14 flows from this oil inlet 14 into the oil passage 10a on the intake side, and the lubricating oil is supplied to the oil passage 10a on the intake side. The oil flows through passages 12 and 13 to the oil passage 10b on the exhaust side. This means that the oil passages 10a, 1
2. This means that the dynamic pressure of the lubricating oil flowing in the closed circuit formed by 10b and 13 is highest in the oil passage 10b on the exhaust side, which is the farthest position from the oil inlet 14. A larger amount of lubricating oil will be discharged from the oil supply port 8b of the camshaft bearing portion 4b.

Note that although FIG. 1 shows an oil filler port 15 for supplying lubricating oil to the packet guide hole 5, this oil filler port 15
The oil passages 10a and 10 are connected to each other via a communication oil passage (not shown).
b, thereby supplying oil to the packet guide hole 5.

16 is a mounting hole for a spark plug.

As is clear from the above explanation, according to the present invention, a larger amount of lubricating oil is supplied to the camshaft bearing portion 4b on the exhaust side of the RAD 1 to the cylinder, which is at a higher temperature than the intake side. , which eliminates the risk of insufficient lubricating oil quantity due to deterioration of lubricating oil due to high temperatures;
The configuration of the present invention that can supply a larger amount of lubricating oil to the camshaft bearing portion 4b on the exhaust side is as shown in this embodiment in which the valves are directly driven through the lash adjuster. There is special significance in this case. That is, as is clear from FIGS. 1, 4, and 5, the bearing surfaces 7a of the camshaft bearings 4a, 4b
, 7b are formed narrow in width to avoid interference with the lash adjuster packet. On the other hand, in this type of engine, when the intake side is on the left side as shown in the figure, the cam shirts 2a and 2b both rotate clockwise as shown in Figure 3, so the cam on the intake side As shown in FIG. 4, the oil supply port 8a of the shaft bearing part 4a is necessarily located on the advancing side with respect to the rotational direction of the camshaft 2a, but the oil supply port 8a of the camshaft bearing part 4b on the exhaust side is As shown in FIG. 5, the opening 8b is necessarily located on the lag side with respect to the rotational direction of the camshaft 2b. Therefore, in the camshaft bearing part 4a on the intake side, the entire amount of lubricating oil discharged from the oil supply port 8a is used to lubricate the bearing part 4a, whereas in the camshaft bearing part 4b on the exhaust side, A phenomenon occurs in which a part of the lubricating oil discharged from the oil filler port 8b falls from above the bearing surface 7b in the narrow part of the bearing surface, and only a portion of the lubricant oil supplied from the oil filler port 8b is provided for lubrication. Become. Therefore, unless the amount of oil supplied from the oil filler port 8b is increased, there is a risk that the lubricating oil will deteriorate due to the high temperature and the lubricating function will become insufficient. For the above reasons,
The configuration of the lubricating device according to the present invention is as shown in this embodiment.
This is particularly effective in OHC engines.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the cylinder throat of a DOHC engine to which the present invention is applied, with the camshaft removed;
Figure 2 is a cross-sectional view taken along line nn in Figure 1, and Figure 3 is a cross-sectional view of Figure 1.
A cross-sectional view taken along line m-m in the figure, Figure 4 is It/- of Figure 3.
A cross-sectional view of the camshaft bearing on the intake side as seen from the rV line,
FIG. 5 is a sectional view of the camshaft bearing portion on the exhaust side as seen from the line V--■ in FIG. 3. 1-Cylinder head 2a12b--Camshaft 3a, 3b-Camshaft axis 4a, 4b-Camshaft bearing portion 5-Bakeno l-X inner hole 6-Bakenoto support portion 7a, 7
b-bearing surface 8a, 8b-oil filler port 9a29b-bearing cap 10a, 10b, lla, llb, 12.13-oil path
14 - Oil inlet 15 - Fuel filler port 16 - Spark plug mounting hole Patent applicant Mazda Motor Corporation representative Patent attorney Toshihito Yamamoto Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] A lubricating oil supply device for a DOHC engine having a cylinder head having two intake valves and two exhaust valves for each cylinder, and a camshaft bearing between each of these two valves. An oil passage is formed in the cylinder head as a closed passage that extends over the intake side and the exhaust side of the cylinder head and communicates with the oil supply port for each camshaft bearing,
The DOHC engine is characterized in that an oil inlet of the oil passage is provided on the intake side, and the lubricating oil is introduced from the oil inlet and flows in the oil passage, and flows to the exhaust side. Lubricating oil supply device.