JPS6232322B2 - - Google Patents

Abstract

PURPOSE:To have long-term supply of lubricating oil to the sliding surface of a cam in the dynamic valve system of a car by fitting an oil supplying tip while the cam shaft is in such a condition that its foremost part equipped with an oil outlet is protruding inward in the oil path. CONSTITUTION:One end of a processing hole 4 is open to an oil path 3 excavated in the cam shaft while the other end is open to the sliding surface of the cam. An oil supplying tip 5 shall be driven in the processing hole 4 so deep that the foremost part equipped with an oil outlet 5a protrudes inward for a certain specified distance l from the inside surface of oil path 3. Because it takes a certain while before the sludge 7 grows till a distance l corresponding to tip protrusion, the oil outlet 5a in the tip 5 can work for a long time before it is stopped up, to assure long-term supply of the lubricating oil to the sliding surface of the cam in good performance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camshaft with improved lubricity.

A camshaft used in automobile valve train systems consists of a camshaft body (hereinafter simply referred to as the shaft body) and a plurality of cam pieces (hereinafter simply referred to as cams) arranged at predetermined positions on the shaft body.
It also consists of journal pieces, etc.
Lubricating oil is constantly supplied to the cam sliding surface. To supply lubricating oil to this camshaft, for example, a hollow shaft member is used in the shaft body, and the hollow portion of the shaft member is connected to a lubricating oil supply passage (hereinafter simply referred to as an oil passage).
A method in which lubricating oil is supplied to the cam sliding surface through the oil passage in the shaft body and the oil supply hole in the cam, or a camshaft. The camshaft itself does not have an oil supply passage, but a separate oil supply device is provided outside the camshaft, and the cam sliding surface is supplied with oil from this device.

However, in the former so-called internal lubricant supply method that utilizes the oil passage in the hollow shaft body and the oil supply hole in the cam, the diameter of the oil supply hole is small, so when the lubricant deteriorates, it will leak inside the oil supply hole, especially Sludge, etc. adheres near the opening end of the oil passage of the oil supply hole, and this gradually grows and blocks the oil supply hole, gradually reducing the amount of oil supplied to the cam sliding surface, resulting in poor lubricant supply to the cam sliding surface. There is a risk of causing Increasing the diameter of the oil supply hole may be considered as a measure against the growth of sludge, etc. in the oil supply hole, but due to the increase in the amount of lubricant flowing out from the camshaft, the amount of lubricant supplied to other parts will decrease. This is undesirable as it causes imbalance.

The latter so-called lubricating oil external supply method in which a separate lubricating device is provided is undesirable because it requires a separate device and becomes structurally complex, resulting in increased cost and weight.

The present invention provides a camshaft with an internal lubricating oil supply system, whereby by changing the structure of the oil supply hole, the amount of oil supplied does not decrease due to the growth of oil sludge, etc., and lubricating oil can be supplied to the cam sliding surface for a long period of time. It provides a camshaft.

The camshaft of the present invention has a hole in which one end opens into the oil passage of the camshaft and the other end opens into the cam sliding surface, and the tip portion having an oil outlet protrudes further inward from the oil passage surface for oil supply. It is made by inserting a chip.

Hereinafter, the camshaft of the present invention will be explained based on the drawings.

FIG. 1 is a partial side view of a lubricating oil internal supply type camshaft according to the present invention, FIG.

In FIGS. 1 and 2, 1 is a shaft body, 2 is a cam, and 3 is an oil passage that passes through the camshaft in the axial direction. 4 is the cam base part 2a
This is a machined hole drilled with a drill etc. This machined hole 4 can have a larger diameter than the oil supply hole provided in the conventional cam base.

Reference numeral 5 denotes a lubricating tip (hereinafter simply referred to as a tip) driven into the machined hole 4. Chip 5
As shown in FIG. 2B, it has a cup shape with a closed tip in the driving direction and an open rear end, and has a tapered portion 51 whose diameter increases from the tip toward the rear end, and continues to the widening end of this tapered portion 51. It consists of a cylindrical part 52. The outer diameter of the cylindrical portion 52 is set to be the same as or slightly larger than the inner diameter of the machined hole 4 into which the refueling tip 5 is fitted, and is fitted into the machined hole 4 . An oil spill hole 5a is opened at approximately the center of the tip 5.
The amount of lubricating oil supplied from the tip 5 to the cam sliding surface is determined by the size of the oil outflow hole 5a.

The tip 5 is manufactured in a predetermined shape separately from the camshaft, and is driven into the machined hole 4 of the camshaft. The driving depth of the chip 5 into the processed hole 4 is:
The tip end side having the oil outflow hole 5a is made to protrude inward from the inner circumferential surface of the oil passage 3 by a predetermined distance (indicated by l in FIG. 2A).

In the camshaft constructed as described above, lubricating oil flows from the oil passage 3 of the camshaft into the tip 5 through the oil outflow hole 5a of the tip 5, and is supplied to the cam sliding surface through the machined hole 4. The influence of the growth of sludge, etc. (hereinafter simply referred to as sludge) at this time will be explained in comparison with a conventional camshaft having a structure without chips. In the conventional camshaft, as shown in FIG. 3A, lubricating oil 6 (indicated by dotted lines in the figure) is supplied to the cam sliding surface from an oil supply hole 4' formed in the cam base 2a.
The diameter of the oil supply hole 4' at the opening end on the oil passage 3 side is narrowed in order to adjust the amount of lubricating oil flowing out, and the oil sludge 7 gradually flows into the oil passage 3 after long-term use.
It adheres and grows near the opening of the oil supply hole 4'. Therefore, the amount of lubricating oil supplied to the cam sliding surface decreases.
On the other hand, in the camshaft of the present invention,
As shown in FIG. 3B, the tapered tip of the tip 5 is fitted into the machined hole 4 formed in the cam base 2a with the tip protruding inward by a distance l from the inner peripheral surface of the oil passage 3. , Suratji 7 first got chip 5
The sludge 7 adheres to the gap between the outer circumferential surface of the taper portion 51 and the inner circumferential surface of the machined hole 4 and gradually grows, but it takes time for the sludge 7 to grow to the protruding distance l of the chip 5. As a result, the oil outflow hole 5a of the tip 5 is less likely to be clogged, and a decrease in the amount of lubricating oil supplied to the cam sliding surface is prevented. In particular, the camshaft of this embodiment has the tip end portion of the oil supply tip tapered as shown in the figure, so that the tapered portion 5
A gap is created between the outer circumferential surface of the chip 1 and the inner circumferential surface of the machined hole 4, and sludge initially accumulates in this gap, so that the sludge reaches the tip surface of the chip 5, which is provided with the oil spill hole 5a. It takes a very long time to grow up to the point where the lubricating oil is supplied to the cam sliding surface for a long period of time.

The longer the tip protrusion distance l is, the better, since it will not be affected by sludge growth, but if it is too long, it will obstruct the flow of lubricating oil in the oil passage 3, and the tip 5
This is not preferable because the lubricating oil leakage from the oil spill hole 5a is obstructed. Therefore, the protrusion distance l is determined taking the above points into consideration, but in a standard size camshaft normally used in an automobile valve train, l is approximately 1 to 5 mm.

The shape of the chip used in the present invention is not limited to that of the above embodiment. For example, it may have a truncated conical shape, a stepped cylindrical shape in which cylindrical portions with different diameters are connected in series, or the like. The oil outlet provided at the tip end may be provided with a small hole on the tip surface as shown in the figure, or the entire tip may be open. The material of the chip is not particularly limited, but includes, for example, SPCC (cold rolled steel plate), BSBME (free cutting brass steel), and the like.

The camshaft is not limited to that of the above-mentioned example, but it may also be one in which an oil passage is provided in the shaft body and a cam having a machined hole that communicates with the oil passage is assembled and joined, or the oil passage and the hole for inserting the chip are in a predetermined position. Any lubricating oil supply type may be used, such as a cast type that is provided with lubricating oil. When creating a machined hole, it can be made larger in diameter compared to conventional oil supply holes, so even if the hole is drilled from the cam sliding surface side, there will be no edges at the end of the machined hole on the oil passage side. It does not protrude and is easy to work with.

As is clear from the above description, in the camshaft of the present invention, a lubricating tip is provided at a predetermined position of the cam so that the tip portion of the tip having the oil outlet protrudes inward of the oil passage of the camshaft (processing).
Since it has a structure that fits into the hole, the oil outlet of the chip is unlikely to be blocked even if sludge etc. adheres and accumulates.
Lubricating oil is well supplied to the cam sliding surface over a long period of time. In addition, since the lubricating tip is manufactured separately, it can be manufactured easily and precisely even if it is small and has a complicated shape.The diameter of the oil outlet can also be selected within an appropriate range, so the amount of lubricating oil flowing out can be adjusted to the optimal range. The oil amount balance in the automobile valve train system will not be disrupted. Therefore, the camshaft of the present invention has the advantage that the lubricating oil is well supplied to the cam sliding surface over a long period of time, so that the wear resistance and seizure resistance of the cam can be maintained at a high level.

[Brief explanation of the drawing]

Fig. 1 is a partial side view of a lubricant internal supply type camshaft, Fig. 2A is a sectional view taken along the line - - in Fig. 1, Fig. 2 is a perspective view showing an example of a lubricating tip used in the present invention, Figure 3A is an enlarged sectional view of the main part showing an example of sludge growth in a conventional camshaft.
The same figure shows an enlarged sectional view of a main part showing an example of sludge growth in the camshaft of the present invention. 1... Shaft body, 2... Cam, 3... Oil passage, 4... Machining hole, 5... Oil supply tip, 6...
Lubricating oil, 7...sludge.

Claims (1)

[Scope of Claims] 1. A hole whose one end opens into an oil passage inside the camshaft and whose other end opens into a cam sliding surface, with a tip portion having an oil outlet protruding further inward from the oil passage surface. A camshaft in which a lubricating tip is fitted.