JPH0748963Y2 - Cam lubricator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an improvement of a cam lubrication device, for example, an oil delivery pipe for cam lubrication.

(Prior Art) As a conventional cam lubrication device, for example, there is one as shown in FIG. 4 (refer to “Lubrication” vol. 27 No. 5 1982 page 358 issued by the Japan Society of Lubrication in May 1982). .

A port 2 is formed in the cylinder head 1, and a valve 4 is mounted so as to be slidable inside a valve guide 3 press-fitted into the cylinder head 1.
A retainer 6 to which one end of a spring 5 for urging the valve 4 in the valve closing direction contacts is attached near the top end of the.

Further, a cam shaft 8 having a cam 7 formed to be biased to one side above the valve 4 is pivotally supported, and the cylinder head 1 is substantially parallel to the valve 4 on the side opposite to the valve 4 with the cam 7 interposed therebetween. Further, a lash adjuster insertion hole 15 is formed by pointing upward, and a hydraulic lash adjuster 16 is fitted in the insertion hole 15 so as to be retractable. One end of the rocker arm 9 is slidably supported by a tip spherical bearing portion 18 of a plunger 17 of the lash adjuster 16, and a curved sectional shape (hereinafter referred to as a crowning shape) formed on an upper portion of the rocker arm 9. The center upper surface of the rocker arm tip 10 having the sliding contact surface 10a) contacts the cam 7, and the valve contact portion 11 at the other end of the rocker arm 9 contacts the top end of the valve 4.

Further, a hollow cylindrical oil delivery pipe 12 is provided parallel to the axial direction of the camshaft 8 above the center extension of the camshaft 8 and extends through the center of the cam 7 in the width direction. In the upper pipe 12, the hollow part of the pipe 12
An oil jet hole 14 for lubricating the lubricating oil 13 in the cam 12a with the rocker arm tip 10 of the cam 7 is formed, and the lubricating oil is jetted and supplied toward the substantially center extension of the camshaft 8. It

Reference numeral 19 in the drawing denotes a valve seat with which the valve face 4b formed on the umbrella portion 4a of the valve 4 abuts, 20 indicates a cooling water passage formed on the cylinder head 1, and R indicates a rotational direction of the camshaft 8. ing.

(Problems to be Solved by the Invention) However, in such a conventional cam lubrication device, the oil jet hole 14 formed in the oil delivery pipe 12 is formed approximately on the center extension of the cam shaft 8. Lubricating oil is jetted and supplied toward the substantially center extension of the camshaft 8, and the lubricating oil 13 is slidably contacted to only one cam 7 from only one oil jet hole 14.
Since it is configured to inject toward the 7a, the lubricating oil 13 is insufficiently supplied to the entrainment side of the lubricating oil 13 due to the rotation of the cam 7, and at the time of high engine speed injection from the oil jet hole 14 The momentum of the lubricating oil 13 is increased, the lubricating oil 13 is scattered from the sliding contact surface 7a, and it becomes impossible to supply a sufficient amount of the lubricating oil 13 to the sliding contact surface 7a. 7 and rocker arm tip 10 sliding contact surface
There is a problem that 7a and 10a are significantly worn.
Further, since the rocker arm tip 10 has the crowning shape, the lubricating oil 13 is removed from the central portions of the sliding contact surfaces 7a and 10a, which makes the above problem more remarkable.

[Structure of the Invention] (Means for Solving the Problems) A cam lubricating device of the present invention for achieving the above object is a valve opening / closing mechanism for opening and closing a valve, which is arranged near a cam shaft. In a cam lubrication device having an oil jet hole for supplying lubricating oil to a sliding contact portion with a cam formed on a shaft, the oil jet hole is separated from a single cam in a plurality of positions in the axial direction of the cam shaft. In addition to the central axis of the camshaft, the oil jet hole is provided to the cam so that the injected lubricating oil is directed in the direction in which the injected lubricating oil comes into contact with the cam event portion of the cam on the side where the lubricating oil is entrained as the cam rotates. Placed offset.

(Operation) In the above configuration, since the oil jet holes are provided at a plurality of positions in the axial direction of the cam shaft for one cam, the lubricating oil is supplied over a wide range in the cam axial direction of the cam. . Further, the oil jet holes are arranged offset from the central axis of the cam shaft so that the injected lubricating oil is directed in the direction of coming into contact with the cam event portion of the cam on the side where the lubricating oil is entrained as the cam rotates. Before the cam event part comes into sliding contact with the valve opening / closing mechanism, most of the injected lubricating oil is always caught in the cam event part and used for lubrication of the sliding contact part, and also actively over a wide range of the sliding contact surface. Lubricating oil is supplied.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

However, the same parts as those of the conventional example are designated by the same reference numerals, and the description thereof will be omitted. Only different parts will be described.

FIG. 1 shows a first embodiment of the present invention, which has an outer diameter of φ10.
mm, the oil delivery pipe 12 with an inner diameter of φ6 mm has two oil jet holes 2 of φ1.5 mm each for one cam 7.
1a and 21b are formed, and the oil jet holes 21a and 21b are arranged so that the injected lubricating oil 13 comes into contact with the cam event portion 7b on the winding side of the lubricating oil 13 accompanying the rotation of the chill cast iron cam 7.
The oil delivery pipe 12 is provided below the oil delivery pipe 12, and the center of the oil delivery pipe 12 is the camshaft 8.
It is provided offset from the center line X passing through the center by L. (See Fig. 1A) Also, oil jet holes 21a, 21
b is formed at an angle of θ ₁ with respect to a center line X ′ passing through the center in the width direction so that the injected lubricating oil 13 intersects at the approximate center in the width direction of the sliding contact surface 7a (see FIG. 1B). ). 7
c is the cam nose top, which is the top of the cam 7, and 23 is 1
A rocker arm tip 23a made of high chromium cast iron containing 0% or more of Cr indicates a sliding contact surface.

The operation of the above configuration will be described. For one cam 7, the lubricating oil 13 is supplied from the oil jet holes 21a and 21b at two locations.
Therefore, the amount of lubricating oil supplied to the sliding contact surface 7a increases.

Further, since the lubricating oil 13 is jetted so as to come into contact with the cam event portion 7b on the winding side of the lubricating oil 13, most of the jetted lubricating oil 13 is always provided before the cam event portion 7b makes sliding contact with the rocker arm tip 23. Is used to lubricate the sliding contact portion by being caught in the cam event portion 7b, and the lubricating oil 13 is positively supplied over a wide range of the sliding contact surface 7a, so that the sliding contact surface 7a, the cam nose top 7c, and the rocker arm. The wear of the tip 10 can be significantly reduced.

Furthermore, the lubricating oil 1 injected from the oil jet holes 21a, 21b
Since 3 intersects at approximately the center of the sliding contact surface 7a in the width direction, the lubricating oil 13 from both sides collides there and is diffused on the sliding contact surface 7a. Lubricating oil 13
Will be supplied.

Next, a second embodiment of the present invention will be described with reference to FIG. 2. In this embodiment, the oil delivery pipe 12 on the center extension of the sliding contact surface 7a in the width direction of the first embodiment will be described. Furthermore φ
The 1.5 mm oil jet hole 21c is provided to increase the supply amount of the lubricating oil 13 and promote the diffusion of the lubricating oil 13 on the sliding contact surface 7a, which further reduces the wear of the cam nose top 7c and the rocker arm tip 10. Can be reduced.

Furthermore, the third embodiment of the present invention will be described based on FIG. 3 for the differences from the first embodiment. The oil jet holes 22a and 22b are arranged so that the injected lubricating oil 13 intersects in the space 24 between the cam nose top 7c and the oil delivery pipe 12 on the center extension of the sliding contact surface 7a in the width direction. Are formed at an angle of θ ₂ (θ ₂ > θ ₁ ) with respect to a center line X ′ passing through the center of the width direction of. With the above configuration, the lubricating oil 13 from both the oil jet holes 22a and 22b collides in the space 24 and is diffused in a mist state, so that the diffused lubricating oil 13 is reliably spread over the entire width of the sliding contact surface 7a. Is supplied to improve the lubrication.

Next, the conditions and results of the durability test in which the above-described respective examples and the conventional cam lubrication device were incorporated into the engine will be respectively described below.
The results are shown in Table 2 and Table 2.

From the above test results, it can be seen that the wear depth can be suppressed to about 3% as compared with the conventional cam lubrication device in each example, and as the number of oil jet holes is increased, the lubrication injected again It is understood that the wear of the cam nose top and the rocker arm tip can be prevented as the oil intersecting portion is located above the sliding contact surface. still,
Although not shown in the table, even if the number of oil jet holes is increased to four or more, the effect is not much different from the effect in each of the above-described embodiments, and the increase in the oil pressure causes a decrease in hydraulic pressure, which in turn causes a shortage of lubricating oil supply. There is 2 for each cam
It is desirable to form three oil jet holes.

(Effects of the Invention) As described above, according to the present invention, the oil jet holes are provided at a plurality of locations in the axial direction of the cam shaft for one cam, and the oil jet holes are injected for the cam. Since the lubricated oil is arranged offset from the central axis of the camshaft so that it points in the direction of contacting the cam event portion of the cam on the side of the oil entrained by the rotation of the cam, a wide range in the camshaft axial direction of the cam Lubricating oil can be supplied over. Further, before the cam event portion makes sliding contact with the valve opening / closing mechanism, most of the injected lubricating oil is always caught in the cam event portion and can be used for lubrication of the sliding contact portion, and the sliding contact surface can be widely used. Since the lubricating oil can be positively supplied over the entire range, it is possible to prevent the oil film from running off at the sliding contact portion and significantly reduce wear.

[Brief description of drawings]

FIG. 1 shows an embodiment of a cam lubrication device according to the present invention. FIG. 1A is a side view showing a partial cross section, and FIG. 1B is a partial cross section seen from the arrow Y direction in FIG. 1A. 2 and 3 are front views showing other embodiments, FIG. 4 shows a conventional example, and FIG. 4A is a side view showing a partial cross section.
FIG. 4B is a front view showing a partial cross section as viewed in the direction of the arrow Y in FIG. 4A. 7 ... Cam, 8 ... Cam shaft, 10,23 ... Rocker arm tip, 12 ... Oil delivery pipe, 14,21,21a, 21b, 21
c, 22a, 22b ... Oil jet holes.

Claims (1)

[Scope of utility model registration request] 1. A cam having an oil jet hole which is arranged near a cam shaft and which supplies lubricating oil to a sliding contact portion between a valve opening / closing mechanism for opening and closing a valve and a cam formed on the cam shaft. In a lubrication device, b) the oil jet hole is provided at a plurality of locations in the axial direction of the camshaft with respect to one cam, and c) the lubricating oil injected from the oil jet hole into the cam is The cam lubrication device is arranged offset from the central axis of the cam shaft so as to be oriented in the direction of contacting the cam event portion of the cam on the side where the lubricating oil is entrained due to the rotation of.