JPS6316567B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil supply device that supplies lubricating oil to a movable shaft such as an exhaust valve of a diesel engine.

Conventionally, lubricating the sliding parts of the valve guide and valve stem of a diesel engine has been done by forming spiral grooves or vertical grooves on the inner peripheral surface of the valve guide and letting lubricating oil flow through these grooves. Since it is a lubrication system, it is difficult to lubricate the appropriate amount of lubrication, and insufficient lubrication can cause premature wear, seizure, or exhaust gas blowing into the cylinder head bonnet. For this reason,
A system has been developed in which an independent oil supply machine is installed to forcibly supply lubricating oil to the valve guide, but this has the drawbacks of being complex, expensive, and prone to failure. .

The present invention includes a movable shaft that is movably inserted in the axial direction into a shaft hole that is connected to an oil reservoir and is provided in a guide member, a seal ring groove is formed on the inner peripheral surface of the shaft hole, and a seal ring groove is formed on the inner peripheral surface of the shaft hole. A seal ring that moves in the axial direction of the movable shaft together with the movable shaft is inserted into the groove by fitting onto the outer periphery of the movable shaft, and the outer periphery of the seal ring and the inner periphery of the seal ring groove on the moving surface of the seal ring are inserted. This solution solves the above-mentioned conventional problems by providing a gap for the flow of lubricating oil between the sliding parts and the sliding parts, and the structure is simple and inexpensive. , an object of the present invention is to provide a lubricating device for a movable shaft. Hereinafter, the present invention will be explained with reference to the drawings.

FIGS. 1 to 3 show an embodiment of the present invention, and in these figures, reference numeral 1 indicates a valve guide (guide member). A circular shaft hole 1a is bored in the center of this valve guide 1, and the shaft hole 1a
A valve stem (movable shaft) 2a of the exhaust valve 2 is inserted into the exhaust valve 2 so as to be movable in the axial direction. Above exhaust valve 2
The valve main body 2b provided at the lower end of the valve stem 2a (in FIG. 1) is brought into close contact with the valve seat 3 to close the exhaust hole 4. As is well known, the valve body 2b provided at the lower end of the valve stem 2a (in FIG. The upper end of the valve stem 2a is pushed against the elasticity of the valve body 5, thereby separating the valve body 2b from the valve seat 3 and opening the exhaust hole 4.

An oil reservoir 1b is located on the upper end surface of the valve guide 1.
A seal ring groove 1c is provided in the upper inner peripheral surface of the shaft hole 1a of the valve guide 1. The oil reservoir 1b receives lubricating oil supplied from a lubricating oil supply source (not shown), and is formed between the outer peripheral surface of the valve stem 2a and the inner peripheral surface of the shaft hole 1a. The seal ring groove 1c is connected to the seal ring groove 1c through a relatively large gap G of, for example, about 0.2 mm. Further, a seal ring 6 such as an O-ring made of rubber or an equivalent material is placed in the seal ring groove 1c.
The lubricating oil is inserted between the inner circumferential surface of c and the outer circumference of the seal ring 6 with a slight gap R for lubricating oil flowing therebetween.
The length l of the seal ring groove 1c is determined so that the moving distance (lt) of the seal ring is slightly smaller than the moving stroke of the valve stem 2a, where t is the wall thickness of the seal ring 6, and the seal ring groove 1c is The ring 6 is relatively tightly fitted onto the valve stem 2a. With the above configuration, the seal ring 6
follows the axial movement of the valve stem 2a relative to the valve guide 1, and moves up and down within the seal ring groove 1c in FIGS. 2 and 3.

Next, the operation of the oil supply system of the present invention configured as described above will be explained.

As is well known, the exhaust valve 2 moves up and down by the action of the locking arm and the spring 5,
The exhaust hole 4 is opened and closed in synchronization with the movement of the exhaust valve 2, and lubricating oil is supplied to the oil reservoir 1b by a required means in conjunction with the operation of the exhaust valve 2.

Fig. 2 shows a state in which the exhaust valve 2 is lowered, the valve body 2b is separated from the valve seat 3, and the exhaust hole 4 is opened, and the seal ring 6 is in contact with the lower surface F1 of the seal ring groove 1c. Since the small gap g between the outer circumferential surface of the valve stem 2a and the inner circumferential surface of the shaft hole 1a is closed, exhaust gas will not blow upward through the gap g. The exhaust valve 2 which has opened the exhaust hole 4 immediately rises to close the exhaust hole 4, but following the rise of the exhaust valve 2, the seal ring 6 rises within the seal ring groove 1c. At this time, the lubricating oil in the seal ring groove 1c moves below the seal ring 6 through a small gap between the outer peripheral surface of the seal ring 6 and the vertical surface F2 of the seal ring groove 1c.

When the exhaust valve 2 moves up with the seal ring 6 as shown in FIGS. 1 and 3 and finishes closing the exhaust hole 4, it moves down again with the seal ring 6. On this occasion,
The seal ring 6 presses the lubricating oil in the seal ring groove 1c downward and forces it into the gap g between the valve stem 2a and the shaft hole 1a, and also fills the oil reservoir 1b.
The lubricating oil inside is sucked into the seal ring groove 1c.

The seal ring 6 has a special function as a so-called check valve, which allows the lubricating oil to move downward when it goes up, and conversely prevents the oil from moving upward when it goes down. Although not always, the upper gap G of the seal ring groove 1c is relatively large and the lower gap G is relatively small, and the flow (suction) resistance of the lubricating oil is smaller than the gap G.
Since the gap g side is larger than the above, and gravity acts from the top to the bottom, an appropriate pumping action occurs when the seal ring 6 moves.

FIGS. 4 and 5 show another embodiment of the present invention, and this example has a lubricating oil passage groove (flow gap) in the upper surface F3 and the upper half of the vertical surface F2 of the seal ring groove 1c. 7 is formed. In this oil supply device, when the seal ring 6 moves upward through the passage groove 7, the lubricating oil moves to the lower side of the seal ring 6 through the passage groove 7, and the seal ring 6 moves upward through the passage groove 7. When moving downward through the lower part of the seal ring groove 1c where no seal ring is formed, a pumping action occurs and the lubricating oil is forced downward. Note that the same effect as above can be obtained by forming part or the entire vertical surface F2 of the seal ring groove into a tapered shape that tapers upward as shown in Fig. 6 or tapers downward as shown in Fig. 7. You can also do it.

In the above embodiment, the seal ring groove 1c
The length l is the moving distance of the seal ring 6 (l-
In this example, t) is slightly smaller than the movement stroke of the exhaust valve 2, but the movement stroke of the stem 2a may be sufficiently larger than (lt).
Note that the amount of oil supplied can be adjusted by selecting the moving distance (lt) of the seal ring 6 within a dimensional range that is equal to or less than the moving stroke of the stem 2a. It is also possible to provide vertical grooves or spiral grooves on the inner circumferential surface of the shaft hole 1a and the outer circumferential surface of the valve stem 2a as in the conventional case. Further, although the above description has been made regarding the case where the present invention is applied to an exhaust valve of an internal combustion engine, the present invention can be applied to any other device as long as the shaft is movably inserted into the shaft hole.

As explained above, in the oil supply device of the present invention, the movable shaft is movably inserted in the axial direction into the shaft hole provided in the guide member and communicated with the oil reservoir, and the inner peripheral surface of the shaft hole is sealed. A ring groove is formed, and a seal ring that moves together with the movable shaft in the axial direction of the movable shaft is inserted into the seal ring groove by being fitted around the outer periphery of the movable shaft. A lubricating oil circulation gap is provided between the outer periphery of the seal ring and the inner periphery of the seal ring groove, and as the movable shaft moves, the seal ring moves within the seal ring groove and pumps. Since the lubricating oil has an action, an appropriate amount of lubricating oil can be evenly and accurately fed into the gap between the movable shaft and the shaft hole. Therefore, wear of the guide member and movable shaft can be suppressed as much as possible to extend their lifespan, and when used in the exhaust valve of an internal combustion engine, the presence of a seal ring and the presence of an oil film in the gap can be avoided. Maintenance has the advantage of preventing exhaust gas from blowing through. Moreover, since the structure is simple,
It has the advantage of being easy to implement and being inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an exhaust system for a diesel engine equipped with the oil supply system of the present invention, FIGS. 2 and 3 are cross-sectional views of the oil supply system of the present invention, and FIG. FIG. 5 is an enlarged sectional view taken along the line --- in FIG. 4, and FIGS. 6 and 7 are sectional views showing two other embodiments of the present invention. 1... Valve guide (guide member), 1a...
Shaft hole, 1b... Oil reservoir, R, 7... Distribution gap, 1
c...Seal ring groove, 2a...Valve stem (movable shaft), 6...Seal ring.

Claims (1)

[Claims] 1. A movable shaft is movably inserted in the axial direction into a shaft hole provided in a guide member and communicated with an oil reservoir, and a seal ring groove is formed on the inner peripheral surface of the shaft hole, and a seal ring groove is formed in the inner peripheral surface of the shaft hole. A seal ring that moves in the axial direction of the movable shaft together with the movable shaft is fitted and inserted on the outer periphery of the movable shaft, and the outer periphery of the seal ring and the inner periphery of the seal ring groove on the moving surface of the seal ring are inserted. A lubrication device for a movable shaft such as an exhaust valve, characterized in that a lubricating oil circulation gap is provided between the surface and the surface.