JPH01170703A - Valve system for engine - Google Patents

Abstract

PURPOSE:To supply sufficiently lubricating oil to a slide section on the front side in the rotational direction of a cam shaft having on both sides intake and exhaust rocker arms disposed by providing a means forming an oil injection path in the boss of rocker arm for example. CONSTITUTION:On both upper sides of a cam shaft 22 disposed on the upper central portion of a cylinder head 31 are respectively disposed rocker arm shafts 23, 24 in which fit slidably respectively bosses 25a, 28a of respective exhaust and intake rocker arms 25, 28. Thus, the respective bosses 25a, 28a overlap each other axially of the cam shaft 22 while being formed with respective oil injection paths 62, 60 opening to each other. The respective rocker arm shafts 23, 24 are formed respectively with communicating paths 63, 61 for affording and interrupting communication between the respective oil supply paths 58, 49 and oil injection paths 62, 60.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a valve train for an engine, and more specifically, the present invention relates to a valve train for an engine. This invention relates to a lubrication mechanism for sliding parts.

(Conventional technology) The so-called 5OHC is used in engines installed in automobiles, etc.
There is something called an engine. In the valve train of this 5OHC engine, two rocker arm shafts are arranged parallel to each other on both sides of one camshaft located above the cylinder head, and the intake and exhaust valves also provided in the cylinder head are opened and closed. Rocker arms for driving are swingably supported on the rocker arm shafts. and,
A suction provided at one end of each of the rocker arms on the camshaft;
When brought into contact with the exhaust cam, these rocker arms are caused to swing according to the rotational movement of the camshaft, and the swinging movement opens and closes the intake and exhaust valves at predetermined timings.

By the way, in such a valve train, since one end of the rocker arm slides against the outer peripheral surface of the cam, it is necessary to lubricate the sliding portion between the two, and conventionally, as this type of lubrication means, For example, there is one described in JP-A-60-88809. This is as shown in Figure 5.
A rocker arm shaft 2 is disposed horizontally in parallel with the camshaft 1 on the upper side of the camshaft 1, which is disposed horizontally in a state perpendicular to the paper surface, and is supported by the rocker arm shaft 2 so as to be freely swingable. In a structure in which the cam contact portion 4 at one end of the rocker arm 3 is brought into contact with the cam 5 on the camshaft 1, and the other end of the rocker arm 3 is brought into contact with the upper end of the stem of the valve 6 from above, the rocker arm 3 is An oil injection passage 8 opening downward is formed in the lower part of the boss part 7 fitted to the rocker arm shaft 2 in the radial direction. An oil supply passage 9 is formed, and a communication passage 10 whose one end is constantly in communication with the oil supply passage 9 and extends downward in the radial direction.
It was formed by When the cam abutting part 4 of the rocker arm 3 rides on the bulge part of the cam 5 and is lifted up, the rocker arm 3 rotates clockwise in the drawing around the rocker arm shaft 2. As shown by the two-dot chain line, the above-mentioned communication path 10 and oil injection path 8
and communicate with each other. Therefore, according to this valve train, when the rocker arm 3 is lifted up,
The lubricating oil supplied to the oil supply passage 9 by appropriate means passes through the communication passage 10 and the oil injection passage 8, and is injected toward the outer peripheral surface of the cam 5 located below.

(Problems to be Solved by the Invention) However, in the above-described lubrication method, regarding the rocker arm 3 disposed on the front side with respect to the rotational direction A of the camshaft 1 shown in FIG. There are two disadvantages: (1) the sliding parts between the cam 4 and the cam 5 cannot be sufficiently lubricated; Since the opening faces forward in the camshaft rotational direction A of the sliding part, lubricating oil is injected toward the front side of the camshaft rotational direction of the sliding part.Therefore, the camshaft 1 is approximately Lubricating oil is supplied to the sliding parts for the first time after one revolution, but during that time, the lubricating oil adhering to the outer circumferential surface of the cam 5 is splashed off by centrifugal force.
The lubricating oil may fall due to its own weight and is not sufficiently supplied to the sliding parts.

In view of these problems, the present invention provides an engine in which rocker arms for intake valves and rocker arms for exhaust valves are arranged on both sides of a single camshaft, respectively. The purpose of this invention is to provide a valve operating device for an engine that can sufficiently supply lubricating oil to the sliding portion between the cam contact portion of the rocker arm and the cam.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, rocker arms for intake valves and exhaust valves are respectively disposed on both sides of one camshaft and supported by rocker arm shafts. A valve operating system for an engine in which a rocker arm is brought into contact with and oscillated by an intake cam and an exhaust cam provided on the camshaft, respectively, is configured as follows.

That is, of the rocker arms on both sides, at least one rocker arm located on the rear side with respect to the rotational direction of the camshaft has a cam contact portion that overlaps in the axial direction of the camshaft with the cam contact portion of the other rocker arm that faces this rocker arm. an oil injection passage opening toward the cam abutting portion of the other rocker arm; A communication path is provided that connects and disconnects the oil supply path and the oil injection path by the rocking motion of one of the rocker arms.

(Function) According to the above configuration, the cam abutting portion of the rocker arm on the front side with respect to the rotational direction of the camshaft has the cam contact portion of the rocker arm located on the rear side with respect to the rotational direction of the camshaft facing the rocker arm. Lubricating oil will be intermittently injected from the oil injection path provided in the boss, but in that case, the lubricating oil injection position will be adjusted between the cam abutting part of the front rocker arm and the cam. It is possible to position the sliding portion on the rear side in the rotational direction of the camshaft, that is, on the front side of the sliding portion.

Therefore, the lubricating oil is supplied to the sliding portion at the same time or immediately after being injected onto the outer peripheral surface of the cam, and a sufficient amount of lubricating oil for the sliding portion is ensured.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

As shown in FIGS. 1 and 2, a camshaft 22 is disposed in the upper center of a cylinder head 21 constituting the engine 20 along the longitudinal direction.

A rocker arm shaft 23 for an exhaust valve is disposed on one side of the upper part of the camshaft 22, and a rocker arm shaft 24 for an intake valve is disposed on the other side in parallel to the camshaft 22. A boss portion 25a at the center of an exhaust rocker arm 25 is slidably fitted onto the negative rocker arm shaft 23, and a cam contact portion provided at one end of the exhaust rocker arm 25 26 comes into contact with an exhaust cam 27 provided on the camshaft 22.

Further, on the other rocker arm shaft 24, a first intake rocker arm 28 facing opposite to the exhaust rocker arm 25 is provided.
A boss portion 28a at the center of is fitted in a swingable manner.

As is clear from FIG. 2, the boss portion 28a of the first intake rocker arm 28 has an axial dimension such that it overlaps the cam contact portion 26 of the exhaust rocker arm 25 and the camshaft 22 in the axial direction. The first intake rocker arm 28 is also provided with a cam abutting portion 3o at one end that abuts the first intake cam 29 provided on the camshaft 22.

In this embodiment, as shown in FIG. 2, the boss portion 25a of the exhaust rocker arm 25 also overlaps with the cam contact portion 30 of the first intake rocker arm 28 in the axial direction of the camshaft 22. The axial dimension is set so that

Further, a second intake rocker arm 31 is provided adjacent to the first intake rocker arm 28, and a boss portion 31a at the center of the second intake rocker arm 31 is pivotally fitted to the rocker arm shaft 24, and a cam at one end. The contact portion 32 is connected to the camshaft 2
It comes into contact with a second intake cam 33 provided at 2.

On the other hand, the cylinder head 21 has a combustion chamber ceiling surface 34 formed by recessing its lower surface upward.
the surface 34 and the cylinder surface 36 of the cylinder block 35;
A combustion chamber 37 is constituted by the upper surface of the piston (not shown). The cylinder head 21 is provided with an intake port 38 that communicates with the combustion chamber 37 from one side, and an exhaust port 39 that communicates with the combustion chamber 37 from the other side. .39 intake and exhaust valves 4 that open and close the openings to the combustion chamber ceiling surface 34
0.41 respectively. Here, although not shown, two intake boats 38 and two intake valves 40 are provided, and as shown in FIG. 1, the first intake boats 38 include a high-load boat 38a and a low-load boat 38b.
It is divided into

The first intake valve 40 that opens and closes the first intake boat 38 has a valve body portion 40a that is seated on a valve seat 42 that is fixed to the opening of the intake boat 38 to the combustion chamber ceiling surface 34.
A stem portion 40b is provided that extends upward from the cylinder head, and this stem portion 40b passes through the cylinder head 21 diagonally upward to the left, and there is a space between the spring retainer 43 attached to the upper end of the stem portion 40b and the upper surface of the cylinder head 22. A valve spring 44 is interposed, and the valve spring 44
The intake valve 4o is held in a closed state by the urging force of the intake valve 4o. Further, the upper end of the stem portion 40b is brought into contact with a plunger 46 of an HLA (high traction lash adjuster) mechanism 45 built in the end of the first intake rocker arm 28 on the side opposite to the cam contact portion. There is. Here, a hydraulic chamber 47 is formed in the upper part of the HLA mechanism 45, and in this hydraulic chamber 47, there is a linear HLA actuator whose negative end opens to the inner circumferential surface of the boss portion of the first intake rocker arm 28. The other end side of the oil supply passage 48 is connected. Further, the rocker arm shaft 24 that supports the first intake rocker arm 28 is provided with an oil supply passage 49 in the longitudinal direction through which lubricating oil supplied by appropriate means passes, and is branched from this oil supply passage 49. A first communication passage 50 that can communicate with the HLA hydraulic oil supply passage 48 is provided in the radial direction of the rocker arm shaft 24 . Note that the above first intake valve 40
The structure of the first intake rocker arm 28 is the same as the structure of the second intake valve or the second intake rocker arm 31.

Furthermore, the exhaust valve 41 has a similar structure to the first intake valve 40, and includes a valve body portion 41a that is seated on a valve seat 51 that is fixed to an opening to the combustion chamber ceiling surface 34 of the exhaust boat 39.
It has a stem portion 41b extending upward from the stem portion 4.
A valve spring 53 is interposed between a spring retainer 52 attached to the upper end of the cylinder head 1b and the upper surface of the cylinder head 21. The exhaust valve 41 is held in a closed state by the biasing force. In this exhaust valve 41 as well, the upper end of the stem portion 41b is brought into contact with the plunger 55 of the HLA mechanism 54 built in the end of the exhaust rocker arm 25 on the side opposite to the cam contact portion. In addition, the above HLA machine side 5
The hydraulic chamber 56 formed in the upper part of the exhaust rocker arm 25 is connected to the other end of an HLA hydraulic oil supply passage 57 whose one end opens to the inner circumferential surface of the boss of the exhaust rocker arm 25, and which supports the rocker arm 25. The rocker arm shaft 23 has
A longitudinal oil supply passage 58 and a radial first communication passage 59 branched from this passage 58 and communicated with the HLA hydraulic oil supply passage 57 are provided.

In addition to the above configuration, the boss portion 28a of the first intake rocker arm 28 has an oil injection passage 60 for the HLA which opens toward the vicinity of the cam contact portion 26 of the opposing exhaust rocker arm 25. It is formed to penetrate on the same straight line as the hydraulic oil supply passage 48 . Further, a second communication passage 61 that is branched from the oil supply passage 49 and can communicate with the oil injection passage 60 is provided in the rocker arm shaft 24 that supports the first intake rocker arm 28 in the radial direction. ing. Also, in the boss portion 25a of the exhaust rocker arm 25, an oil injection passage 62 that opens toward the vicinity of the cam contact portion 30 of the first intake rocker arm 28 is located on the same straight line as the HLA hydraulic oil supply passage 57. It is formed through the
The rocker arm shaft 23 that supports the rocker arm 25 is provided with a second radial communication passage 63 that is branched from the oil supply passage 58 and communicated with the oil injection passage 62 .

According to the above configuration, as shown in FIG.
0 and the exhaust valve 41 are both closed, the camshaft 2
2 rotates in clockwise direction A, as shown in Figure 3,
The cam contact portion 26 of the exhaust rocker arm 25 is connected to the exhaust cam 2.
7 and when the rocker arm 25 swings in the clockwise direction B around the rocker arm shaft 23, the oil injection passage 62 provided in the boss portion 25a and the second communication passage 63 of the rocker arm shaft 23 are connected. While the communication state of
An oil supply passage 49 is connected to the outer peripheral surface of the exhaust cam on the rear side, that is, on the front side, from the oil injection passage 60 of the first intake rocker arm 28 that communicates with the second communication passage 61 of the rocker arm shaft 24.
The lubricating oil inside is supplied by injection. As the camshaft 16 rotates in the A direction, this lubricating oil is immediately supplied to the sliding part between the cam contact part 26 of the exhaust rocker arm 25 and the exhaust cam 27, which is located immediately in front of the camshaft 16 in the direction of rotation. become.

In addition, as shown in FIG. 4, the first intake rocker arm 2
The cam contact portion 30 of No. 8 is lifted up by the first intake cam 29, and the rocker arm 28 is connected to the rocker arm shaft 24.
When rocked in the counterclockwise direction C about the center, communication between the oil injection passage 60 provided in the boss portion 28a and the second communication passage 61 of the rocker arm shaft 24 is cut off; The lubricating oil in the oil supply passage 58 flows from the oil injection passage 62 of the exhaust rocker arm 25 to the sliding part between the cam contact part 30 of the first intake rocker arm 28 and the intake cam 29 through the second communication passage 63. It will be supplied by injection.

In this way, the sliding portion between the cam contact portion 26 of the exhaust rocker arm 25 and the exhaust cam 27 and the sliding portion between the cam contact portion 30 of the first intake rocker arm 28 and the first intake cam 29 are , the lubricating oil is injected from the oil injection passages 60.62 of the rocker arms 28.25 facing each other. Since the injection is supplied directly to the position directly in front of the sliding part or to the sliding part, if it is supplied to a position past the sliding part, it will not scatter around or fall under its own weight before being supplied to the sliding part. In particular, it is possible to sufficiently supply lubricating oil to the cam contact portion 26 of the exhaust rocker arm 25 and the exhaust cam 27 located on the front side with respect to the rotational direction of the camshaft 22. becomes.

Here, in the above embodiment, the HLA hydraulic oil supply passage 48.57 and the oil injection passage 60.62 in the first intake rocker arm 28 and the exhaust rocker arm 25 are provided on the same straight line, respectively. , these can be formed at the same time with one drill bit.

In addition, the oil injection passage 6 in the double-ended hook arm 28.25
0.62 and the second communication passage 61.63 in the rocker arm shaft 24.23 are connected and disconnected by the swinging of the rocker arm 28.25, the lubricating oil from the oil injection passages 60, 62 can be By reducing the injection amount to the minimum required amount, a significant drop in lubricating oil pressure can be avoided.

Note that the first. Cam contact portions 30, 3 of second intake rocker arm 28.31
2 and 1st. As for the sliding part with the second intake cams 29, 33, the rocker arm 28, as in the conventional example shown in FIG.
．． The lubricating oil may be injected from an oil injection path provided in the 31 itself.

That is, in this case, the lubricating oil can be injected directly in front of the sliding portion in the camshaft rotation direction A.

(Effects of the Invention) As described above, according to the present invention, in a configuration in which suction and exhaust rocker arms are arranged on both sides of one camshaft, at least one of the rocker arms on both sides is arranged in the rotational direction of the camshaft. One rocker arm located on the rear side of the rocker arm is provided with a boss portion that overlaps the cam contact portion of the other rocker arm facing this rocker arm in the axial direction of the camshaft. Provide an oil injection path that opens toward the cam contact area,
By intermittently injecting lubricating oil from the oil injection path, the lubricating oil is applied to a position immediately in front of the sliding part between the cam contacting part and the cam of the other rocker arm on the forward side in the rotational direction of the camshaft. It becomes possible to inject it. This makes it possible to supply sufficient lubricating oil to the sliding parts, where lubricating oil was conventionally supplied after approximately one rotation of the camshaft, and the lubricating oil in the sliding parts This will prevent shortages and improve durability.

[Brief explanation of the drawing]

Figures 1 to 4 show embodiments of the present invention. Figure 1 is a vertical sectional view of the upper part of the engine taken along line I-I in Figure 2, and Figure 2 is a partial plan view of the engine. 3 is an enlarged longitudinal sectional view of the main part when the exhaust rocker arm is lifted up, and FIG. 4 is an enlarged longitudinal sectional view of the main part when the first intake rocker arm is lifted up. Moreover, FIG. 5 is a sectional view of a main part showing a conventional example. 22...Cam shaft, 23.24...Rocker arm shaft,
25.28...Rocker arm, 28a...Boss part,
27.29...Cam, 49...Oil supply passage, 6
0...Oil injection path, 61...Communication path.

Claims (1)

[Claims] (1) Intake and exhaust rocker arms supported by rocker arm shafts are arranged on both sides of one camshaft,
A valve operating system for an engine in which these rocker arms are brought into contact with an intake cam and an exhaust cam provided on the camshaft, respectively, and oscillated, the rocker arms on both sides of the rocker arms being rotated at least by the rotation of the camshaft. One rocker arm located on the rear side with respect to the direction is provided with a boss portion that overlaps the cam contact portion of the other rocker arm facing this rocker arm in the axial direction of the camshaft. An oil injection passage that opens toward the cam contact portion of the rocker arm is provided, and the oil supply passage formed in the shaft and the oil injection passage are connected to the rocker arm shaft that supports the one rocker arm. A valve train for an engine, characterized in that a communication passage is provided that is interrupted by dynamic motion.