JPH051612Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a valve operating system for an internal combustion engine in an automobile or the like, and particularly relates to a lubrication structure for a roller in a roller type rocker arm.

<Prior Art> As a conventional valve train for an internal combustion engine, for example, there is one already proposed by the present applicant (Utility Application No. 1983).
-Refer to No. 113626).

To explain this based on FIGS. 8 and 9,
11 is a cylinder head of the engine, and a hydraulic lifter 12 is attached to the cylinder head 11. The hydraulic lifter 12 is connected to the rocker arm body 13.
The locking arm body 1 is engaged with one end of a.
3a is supported freely to swing. An oil passage 12a is formed inside the rocker arm body 13a. On the other hand, the other end of the rocker arm main body 13a is in contact with the base end of a valve 14, and the valve 14 receives the urging force of a valve spring 16 (not shown) compressed between the valve retainer 15 and the cylinder head 11. The intake port (or exhaust port) is closed.

A roller 1 is provided at the center of the rocker arm body 13a.
7 is provided, and the roller 17 is connected to the shaft 18.
It is rotatably supported by. The roller 17 is in contact with a drive cam 19, and the drive cam 19 rotates in response to the rotational force of the crankshaft. The rocker arm body 13a transfers the rotational movement of the drive cam 19 to the roller 17.
It swings vertically in the figure to open and close the valve 14. In this case, the hydraulic lifter 12
The locker arm main body 13a is pressed by lubricating oil pressure from the valve to automatically adjust the valve clearance. A concave oil bathtub 20 is formed in the center of the rocker arm body 13a, and an oil passage 21 is opened near the upper end of the oil bathtub 20.

The oil passage 21 communicates with the oil passage 12a formed inside the hydraulic lifter 12. oil bathtub 20
As shown in FIG. 8, the lower periphery of the roller 17 is housed inside the oil bathtub 20.
Lubricating oil is supplied through oil passages 12a and 21. The oil bathtub 20 is formed by cutting or machining the rocker arm body 13a, and holds lubricating oil therein.

In the above configuration, the lubricating oil supplied from the hydraulic lifter 12 through the oil path 21 accumulates in the oil bathtub 20 and is transferred to the rollers 17, roller shaft 18,
Lubricate the drive cam 19. Since the oil passage 21 opens near the upper end of the oil bathtub 20, the lubricating oil is retained and remains even after the engine is stopped. Therefore, even at the next startup after being stopped for a long time, the contact surfaces of the drive cam 19 and rollers 17, which are subject to high surface pressure, are immediately lubricated by the lubricating oil held in the oil bathtub 20, thereby eliminating noise. This prevents occurrence and abnormal wear. As a result, the durability of the rocker arm 13 and the drive cam 19 can be improved.

In addition, due to such improved durability, the roller 17 with a small diameter can be used.
This makes it possible to reduce the biasing force of the valve spring 16 by downsizing the cylinder head 11 and reducing the mass of the valve train, leading to improved fuel efficiency.

In addition, in this configuration, since the return oil from the hydraulic lifter 12 is used, the lubrication system can be simplified. Furthermore, the required circulation amount of the lubricating oil is reduced, the oil pump capacity can be reduced, and fuel efficiency can be improved by the reduction in pump work.

(Problems to be Solved by the Invention) However, in such a conventional valve train for an internal combustion engine, since a concave oil bathtub 20 is formed in the center of the rocker arm body 13a, Since the rocker arm body 13a around the roller needs to be made thicker, the rocker arm body 13a becomes larger and the weight of the rocker arm body 13a increases.

As a result, the inertial mass of the valve train increases rapidly, resulting in a problem that the surge limit of the valve train is lowered.
Furthermore, in order to guarantee the same surge limit, it is necessary to strengthen the spring, which causes a problem in that the rigidity of the head decreases.

Therefore, the present invention was developed by focusing on these conventional problems, and aims to reduce the weight of the rocker arm body by eliminating the need to form the oil bathtub in the rocker arm body and instead forming it in the cylinder head. Therefore, it is an object of the present invention to solve the above-mentioned conventional problems.

<Means for Solving the Problems> Therefore, in the present invention, a roller is rotatably supported by a rocker arm main body whose one end is supported to freely swing, and the roller receives the rotational movement of a drive cam to operate a valve. In a valve train for an internal combustion engine that is equipped with a rocker arm that opens and closes, an oil bathtub that holds lubricating oil that is supplied to each part by the rollers of the rocker arm coming into contact with each other during valve lift is installed in the cylinder head of each roller part. The configuration is as follows.

<Operation> When the roller of the rocker arm receives the rotational motion of the drive cam and, for example, a valve is fully opened, the roller comes into contact with the oil bathtub, and lubricating oil adheres to the surface of the bathtub, supplying the lubricating oil to each part. Lubricating oil constantly flows into and is held in the oil bathtub, for example, during engine operation. In this configuration, by forming the oil bathtub in the cylinder head,
The lock arm can be made smaller and lighter, and the surge limit of the valve train can be increased.

<Example> Hereinafter, an example of the present invention will be described based on FIGS. 1 to 13.

In FIGS. 1 to 3, the same elements as in FIGS. 8 and 9 are given the same reference numerals to simplify the explanation.

In FIGS. 1 and 2, a roller 17 is rotatably supported by a rocker arm main body 13a whose one end is swingably supported by a hydraulic lifter 12. The structure including the rocker arm 13 that opens and closes is the same as the conventional one, but the roller 17
is disposed in a mounting hole 22 formed vertically through the center of the arm body 13a, and the lower periphery of the roller 17 protrudes from the bottom opening of the mounting hole 22.

An oil bathtub 24 holds lubricating oil that is supplied to each part by contact with the roller 17 of the rocker arm 13 while the valve 14 is lifted.
is formed in the cylinder head 23 for each roller 17.

In this embodiment, when the rocker arm 13 swings to fully open the valve 14, the roller 17
is configured to come into contact with the lubricating oil in the oil bathtub 24.

That is, the oil bathtub 24 has a length extending from the periphery of the hydraulic lifter 12 of the cylinder head 23 to a position facing the roller 17, and is recessed into an oval area having a width larger than the width of the rocker arm body 13a. It is formed. In this case, the tip of the hydraulic lifter 12 protrudes from the upper surface of the oil bathtub 24, and the oil passage 12a opened in the tip surface is located outside the oil bathtub 24.

Next, the operation of this configuration will be explained.

When the roller 17 of the rocker arm 13 receives the rotational movement of the drive cam 19 and the valve 14 is fully opened,
The rocker arm 13 swings as shown by the two-dot chain line in FIG. In this state, the roller 17 comes into contact with the lubricating oil in the oil bathtub 24 and the roller 17
Lubricating oil adheres to the surface of the roller 17 itself,
Lubricate the roller shaft 18 and drive cam 19.
The lubricating oil flowing out from the oil passage of the hydraulic lifter 12 and the lubricating oil circulating during engine operation flow into the oil bathtub 24, and the lubricating oil is always maintained up to the upper surface.

The lubricating oil in the oil bathtub 24 remains as it is even when the engine is stopped, since the oil passage 12a opened at the tip end face of the hydraulic lifter 12 is located outside the oil bathtub 24.
Therefore, even at the next startup after being stopped for a long time, the lubricating oil will not run out, and each part will be sufficiently lubricated, improving durability.

Further, due to such improved durability, the biasing force of the valve spring 16 can be reduced by downsizing the cylinder head 23 and reducing the mass of the valve train, leading to improved fuel efficiency.

Furthermore, since the return oil from the hydraulic lifter 12 is used, the lubrication system can be simplified.

Furthermore, the required circulation amount of the lubricating oil is reduced, the oil pump capacity can be reduced, and fuel efficiency can be improved by the reduction in pump work.

These are the same advantages as conventional devices.

According to this configuration, by forming the oil bathtub 24 on the cylinder head 23, the rocker arm 13 can be made smaller and lighter, the inertial mass of the valve train can be reduced, and the surge limit of the valve train can be increased. Furthermore, there is no need to strengthen the spring in order to guarantee the same surge limit, thereby improving head rigidity.

Further, the oil bathtub 24 is connected to each hydraulic lifter 12.
Since the capacity is compact enough to ensure a space where a portion of each roller 17 can come into contact with the lubricating oil, even if the engine is tilted, lubricating oil can be supplied to each roller 17, and the lubricating oil is supplied. The amount can also be reduced.

Furthermore, since the rocker arm 13 and the hydraulic lifter 12 are arranged so that their swinging fulcrums are constantly immersed in the lubricating oil in the oil bathtub 24, abnormal wear of the swinging fulcrums can be prevented. Since the hydraulic lifter itself is located in the lubricating oil in the oil bathtub 24, there is also the advantage that air from outside the hydraulic lifter 12 is prevented from entering.

FIG. 3 shows another embodiment of the invention.

In this embodiment, a passage 24a for removing air and oil from the bottom of a hole for installing the hydraulic lifter 12 provided in the cylinder head 23 is communicated with the inside of the oil bathtub 24, and a passage 24a for removing air and oil from the bottom of a hole for installing the hydraulic lifter 12 is connected to the oil bathtub 24. The structure is such that leaked oil is also guided into the oil bathtub 24 to ensure lubricating oil within the oil bathtub 24.

The above embodiment is an example in which the present invention is applied to a type of valve train in which one valve 14 is driven by one rocker arm 13, but a valve train of a type in which two valves are driven by one rocker arm ( (See Utility Model Application No. 161157/1983).

To explain this type of valve train,
In FIGS. 10 and 11, two intake or exhaust valves 25a, 25b are provided for each cylinder, and these intake/exhaust valves 25a, 25b are biased to open by a valve spring 26, respectively.
Similarly to the previous embodiment, the cylinder head 27 is provided with a hydraulic lifter 28, and one end of the rocker arm body 29a is supported by the hydraulic lifter 28 so as to be freely swingable.

At the other end of the rocker arm main body 29a, there is a pair of arm parts 29A, 2 that extend from the rocking fulcrum side toward the base ends of the intake/exhaust valves 25a, 25b, respectively.
9B is formed, which causes the rocker arm 29
is formed into a substantially Y-shape. Each of the arm portions 29A,
At the tip of 29B, each intake/exhaust valve 25a, 25b
A valve follower 30 that abuts the end of the valve shaft is formed, respectively. As shown in FIG. 13, an intake/exhaust valve 25 is provided at the end of the valve follower 30.
Flanges 31 are provided to sandwich a and 25b, respectively. Further, a roller 3 that comes into contact with the cam 32 is installed in the assembly hole 36 in the approximate center of the rocker arm body 29a.
3 is rotatably supported.

Further, in the two types of valve operating devices according to the present invention described above, the structure of the roller portion is preferably as follows.

This will be explained based on the above-described valve operating system of the type in which the two valves, that is, the intake valves or the exhaust valves 25a and 25b, are driven by one rocker arm 29.

That is, conventionally, as shown in FIG. 12, the roller 33 has a large number of needle rollers 35 interposed between its inner peripheral surface and the outer peripheral surface of the roller shaft 34.
It is rotatably supported.

In this case, a large number of needle rollers 35 are provided on the inner peripheral surface.
The roller 33 incorporating the
a, and then insert the roller shaft 34 into the roller shaft hole 29b provided in the rocker arm body 29a, and caulk both ends of the roller shaft 34.

A groove or chamfer 37 is provided on the inner surface of the assembly hole 36 corresponding to both end surfaces of the roller 33 and on the cam lobe side. This groove or chamfer 3
7 extends to positions corresponding to both end surfaces of the needle roller 35.

However, such a structure of the roller part has the following problems.

That is, the rock arm main body 29a is made of general steel.
When using something equivalent to S40C, the part where the rotating sides of the roller 33 and needle roller 35 made of bearing steel on the rocker arm body are worn out, and the side clearance changes from a pre-controlled dimension to a dimension that expands over time of use. roller 35
The hitting sound gets louder. Moreover, if the above-mentioned wear is large, the rigidity of the rocker arm 29 will be reduced, and the abrasion will cause cutting powder to enter the rotating surface of the needle roller 35 and destroy the surface of the needle roller 35.
In order to solve these problems, the following configuration is adopted.

That is, as shown in FIG. 4, separate side wall members 38 are attached to the inner surface of the assembly hole 36 corresponding to both end surfaces of the roller 33, respectively. A through hole 38a for the roller shaft 34 is formed in this side wall member 38.

Then, as shown in FIG.
Both ends of the inner surface are cut out into a wedge shape, and both ends of a separate side wall member 38 are fitted into the cutouts and attached.

Therefore, with this configuration, when the needle roller 35 rotates together with the rotation of the roller 33, all of these rotating side surfaces come into contact with the side wall member 38.

Here, if the side wall member 38 is made of a material having the same hardness as the roller 33 and the needle roller 35, the wear of the side wall member 38 itself can be suppressed, and the situation of wear of the rocker arm body 29a can be prevented.

As a result, since the side clearance can be maintained at a pre-controlled dimension, it is possible to prevent the drumming noise of the roller 33 from becoming louder, and also to prevent the rigidity of the rocker arm 29 from decreasing and the surface of the needle roller 35 from being damaged by cutting powder. Note that the rocker arm 29 itself may be formed of an inexpensive steel material.

What is shown in FIG. 6 is such that when the above-mentioned side wall member 38 is provided on the rocker arm main body 29a, a square pipe material 39 is installed in the built-in hole 36 to constitute the side wall member. Compared to the case where a pair of side wall members 38 are provided as shown in the figure,
Easy to incorporate. That is, when providing the pair of side wall members 38, complicated processing such as spigot processing is required for positioning and fixing.
In the case shown in FIG. 4, this is not necessary.

Furthermore, in the case shown in FIG. 5, when installing the side wall member on the rocker arm main body 29a, a U-shaped member 40 is attached in the assembly hole 36 to constitute the side wall member. It is easy to manufacture and is easier to process and form than the square pipe material 39.

<Effects of the invention> As explained above, according to the invention, it is no longer necessary to form an oil bathtub in the rocker arm body, and instead, oil is supplied to each part by the rollers of the rocker arm coming into contact with each other during valve lift. An oil bathtub for holding lubricating oil is formed in the cylinder head for each roller section, which allows for effective lubrication of various parts such as the drive cam, and also reduces the weight of the rocker arm body. This has great practical effects, such as being able to increase the surge limit.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an embodiment of the valve train according to the present invention, and FIG. 2 is a plan view of the same embodiment.
Figure 3 is a front sectional view of another embodiment, Figures 4 to 7.
The figures each show the structure of the roller section applied to the valve train according to the present invention. FIG. 4 is a side view of the roller section, and FIGS. 5 to 7 are plan views of the rocker arm body showing the roller installation holes. 8 is a front sectional view showing an example of a conventional valve operating device, FIG. 9 is a plan view of the same conventional example, FIG. 10 is a front sectional view showing another example of the conventional valve operating device, and FIG. The figure is the plan view, the first
Figure 2 is a sectional view taken along line A-A in Figure 11, and Figure 13 is a cross-sectional view of Figure 1.
0 is a sectional view taken along line BB in FIG. 12, 28... Hydraulic lifter, 13, 29... Rocker arm, 13a, 29a... Rocker arm body, 14... Valve, 17, 33... Roller, 1
9, 32... Drive cam, 23, 27... Cylinder head, 24... Oil bathtub.

Claims (1)

[Scope of utility model registration request] A valve operating device for an internal combustion engine includes a rocker arm in which a roller is rotatably supported by a rocker arm main body whose one end is supported in a freely swinging manner, and the rocker arm receives the rotational movement of a drive cam to open and close a valve.
A valve operating device for an internal combustion engine, characterized in that an oil bathtub is formed in a cylinder head for each roller portion to hold lubricating oil that is supplied to each portion by contact with a roller of a rocker arm during a valve lift.