JP2873990B2 - Valve stem sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve stem sealing device mainly used for intake and exhaust valves of an internal combustion engine.

[0002]

2. Description of the Related Art FIG.
As shown in the figure, the valve stem 5 to which the valve 54 is fixed is shown.
A base end of a seal 52 is fitted and fixed to the end of the valve stem guide 51 on the side opposite to the combustion chamber, which is slidably and loosely fitted, and the lip 53 of the seal 52 is attached to the outer periphery of the valve stem 50. The valve stem is brought into contact with the engine to scrape off the engine oil to form an oil film of a required thickness on the peripheral surface of the valve stem, thereby preventing the valve stem guide 51 from sticking to the valve stem.

[0003]

In the conventional valve stem seal device as described above, the valve stem and the valve stem guide are lubricated by the amount of engine oil leaking from the lip of the valve stem seal. Therefore, in order to maintain lubrication and reduce the consumption of engine oil, the amount of leakage from the valve stem seal must be strictly adjusted, which is not always easy.

[0004] Insufficient amount of engine oil leakage promotes wear of the valve stem and the valve stem guide, and as a result, not only causes abnormal noise and seizure due to insufficient lubrication, but also causes a problem such as seizure. There is also a problem that the temperature of the cylinder head is raised, and an excessive amount of leakage of the engine oil naturally increases the consumption of the engine oil and generates white smoke due to the combustion of the engine oil.

Accordingly, the present invention has been made in view of the above circumstances, and aims to reduce a sliding friction loss by forming a sufficient oil film between a valve stem and a valve stem guide, and to lubricate the oil. Accordingly, it is an object of the present invention to provide a valve stem sealing device which increases a cooling effect and reduces consumption of engine oil.

[0006]

In order to achieve the above-mentioned object, a valve stem sealing device according to the present invention has a valve stem slidably and loosely fitted in a cylindrical valve stem guide, and the valve stem is sealed. The base end of the valve stem seal is fixed to the outer periphery, and a lip protruding downward from the base end is brought into contact with the outer periphery of the valve stem guide, and the valve stem seal is reciprocated as the valve stem reciprocates. A spiral which forms means for causing a pressure difference in the chamber formed by the above and causing the oil to flow into and out of the chamber by the pressure difference, and forming the oil on the inner peripheral portion of the valve stem guide.
To the oil passage via a groove and an oil reservoir provided below the spiral groove
Feeding feeds, that allowed to pumping to the oil chamber side through the check valve from the oil passage and its features, as a means for inflow and discharge the oil to the chamber formed by the valve stem seal, a valve stem guide A radial through hole is formed at a position corresponding to a substantially middle portion of a lip portion of a valve stem seal stroke, or a position corresponding to a substantially middle portion of a lip portion of a valve stem seal stroke of a valve stem guide. The outer diameter of the upper valve stem guide is slightly smaller than the outer diameter of the lower valve stem guide.

[0007]

The valve stem seal device according to the present invention has a valve stem seal base in which a valve stem is slidably and loosely fitted in a cylindrical valve stem guide, and a lip is projected downward on the outer periphery of the valve stem. The end is fitted and fixed, and the lip portion is brought into contact with the outer periphery of the valve stem guide. With the reciprocation of the valve stem, negative pressure and positive pressure are alternately generated in the chamber formed by the valve stem seal. This negative pressure
Since the means for inflowing and discharging oil into and from the chamber formed by the valve stem seal by the repetition of the positive pressure is provided, a sufficient oil film can always be formed around the valve stem and the valve stem can be formed. Since the oil in the room formed by the seal can be circulated, a cooling effect can be obtained. Further, the oil is pressure-fed from the oil passage through the check valve to the oil chamber side to circulate the oil and achieve a cooling effect. To get

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view of a valve stem seal device, FIG. 2 is a first embodiment of a device for flowing oil into and out of a chamber formed by a valve stem seal, and FIG.
A first embodiment will be described with reference to FIGS. 1 and 2. Reference numeral 1 denotes a cylindrical valve stem guide.
The valve stem 2 is slidably and loosely fitted in. Reference numeral 3 denotes a rubber valve stem seal. The valve stem seal 3 fits and fixes a base end portion 5 reinforced by a reinforcing ring 4 to a valve stem near an upper end of the valve stem guide 1, and attaches the lip portion 6 to the valve stem. Of the valve stem guide 1 at a required contact pressure, and slides on the outer periphery of the valve stem guide 1 at a constant stroke as the valve stem 2 reciprocates.

As a means for fixing the valve stem seal 3, as shown in FIG. 2, a base end 5 of the valve stem seal 3 may be fitted and fixed to a step portion of the valve stem 2. For example, there are various means (not shown) such as locking the upper and lower ends of the base end with snap rings engaged with upper and lower grooves formed in the valve stem.

Reference numeral 8 denotes a through hole formed in the radial direction of the valve stem guide 1 at a substantially middle position of the stroke of the lip portion 6 of the valve stem seal 3 which slides vertically on the outer periphery of the valve stem guide 1. Reference numeral 9 denotes a seal member mounted in a space provided on the inner periphery of the lower end of the valve guide 1. The seal member 9 prevents oil for lubricating the outer periphery of the valve stem 2 from leaking to the combustion chamber side. It is to prevent. A spiral groove 10 is provided on the inner periphery of the cylindrical valve stem guide.
The oil sump 11 is communicated with an oil sump 11 formed on the lower inner periphery of the valve stem guide 1, and is moved in one direction through a check valve 13 disposed at an end of the oil passage 12 from the oil sump 11.
The oil inside is supplied to the oil chamber 24.

The above-mentioned check valve 13 may be, for example, a reed valve or a ball valve, and may be any type of check valve.
In the figure, reference numeral 15 denotes a cylinder head, 16 denotes an intake port, 17 denotes a valve seat provided on the intake port 16 side, 18 denotes an intake valve fixed to a lower portion of the valve stem 2, and 20 denotes the intake valve. Camshaft that reciprocates the valve stem 2 against the valve spring 21
2 is a valve lifter, 23 is a spring retainer, and 24 is an oil chamber.

Since the first embodiment is constructed as described above, its operation will be described. The valve stem 2 which is slidably and loosely fitted to the valve stem guide 1 is vertically moved by the rotation of the camshaft 20. As the valve stem 2 reciprocates, the valve stem seal 3 whose base end 5 is fitted and fixed to the valve stem 2 also moves up and down with the reciprocation of the valve stem 2, and the lip portion 6 of the valve stem seal 3 moves. The valve moves up and down within a predetermined stroke while contacting the outer periphery of the valve stem guide 1. At this time, as described above, the base end 5 of the valve stem seal 3 is fitted and fixed to the valve stem 2, and the lip 6 protruding downward from the base end 5 is attached to the valve stem guide 1. Since the outer periphery is in contact with the required contact pressure, the chamber 7 is formed by the valve stem seal 3.

When the valve stem 2 rises, the valve stem seal 3 also rises at the same time, so that the volume in the chamber 7 formed by the valve stem seal 3 increases, and as a result, the chamber 7 In this state, the lip portion 6 of the valve stem seal 3 is located above the outer periphery of the valve stem guide 1. A radial through hole 8 formed substantially at the center of the lip portion 6 of the stroke of the valve stem seal 3 of the guide 1
Is opened outside the chamber 7, so that oil flows into the chamber 7 from the outside through the gap between the valve stem 2 and the valve stem guide 1 through the through hole 8 due to the negative pressure in the chamber 7. Thereby, a sufficient oil film is formed on the outer periphery of the valve stem 2.

When the valve stem 2 moves down,
As a result of the reduction in the volume of the chamber 7 formed by the valve stem seal 3, the inside of the chamber 7 becomes a positive pressure. At this time,
Radial direction of the through hole 8 of the valve stem guide 1, so positioned inside That chamber 7 side of the lip portion 6 of the valve stem seal 3 becomes a closed shape, the oil in the chamber 7 the inner circumference of the valves stem guide 1 The oil is pumped to the oil reservoir 11 formed in the lower inner periphery through the spiral groove 10 provided in the portion .

As described above, in the first embodiment, in order to form a sufficient oil film on the outer periphery of the valve stem 2, the inside of the chamber 7 formed by the valve stem seal 3 by the reciprocating motion of the valve stem 2 is subjected to a negative pressure.・ Alternately generate positive pressure,
As a result, oil flows into and out of the chamber 7 formed by the valve stem seal through the radial through hole 8 formed in the valve stem guide 1, and passes through the spiral groove 10 of the valve stem guide 1 to form the lower inner periphery. As a result, the lubrication of the valve stem 2 is sufficiently achieved and the cooling effect of the valve stem sealing device is increased.

Oil for lubricating the valve stem 2 is supplied to a spiral groove 10 formed on the inner periphery of the cylindrical valve stem guide 1.
Through the oil reservoir 11 provided below the valve stem guide 1, and is supplied to an oil chamber 24 via a check valve 13 through an oil passage communicating with the oil reservoir 11. As described above, the check valve 13 is provided at the tip of the oil passage 12, so that the oil in the oil chamber 24 does not flow back into the oil passage 12.

As described above in detail, according to the first embodiment of the present invention, the lip portion 6 of the valve stem seal 3 in which the base end 5 is fitted and fixed to the outer periphery of the valve stem 2 is connected to the valve stem guide 1. As the valve stem 2 reciprocates, the valve stem seal 3 also has its rib portion 6 slid on the outer periphery of the valve stem guide 1 with a constant stroke. On the other hand, a through hole 8 in the radial direction is formed at a predetermined position of the valve stem guide 1, and the reciprocating motion of the valve stem 2 causes a change in the volume in the chamber 7 formed by the valve stem seal 3. Since a negative pressure and a positive pressure are generated alternately, the oil in the chamber 7 is caused to flow in and out by this pressure difference, so that a sufficient oil film can be formed on the outer periphery of the valve stem 2 and lubrication can be performed. There is no danger of wear and seizure of the valve stem 2 due to shortage, and no increase in the temperature of the cylinder head. In addition, since the seal member 9 is mounted in the space provided on the inner periphery at the lower end of the valve stem guide 1, oil Thus, a valve stem sealing device having no increase in oil consumption or white smoke due to an increase in the amount of oil leakage can be obtained.

FIG. 3 shows a second embodiment of the means for allowing oil to flow into or out of the chamber 7 as the valve stem 2 reciprocates in the chamber 7 formed by the valve stem seal 3. The same parts as those of the embodiment are denoted by the same reference numerals. To explain this, the lip portion 6 of the valve stem seal 3 comes into contact with the outer periphery of the valve stem guide 1 in which the valve stem 2 is slidably and loosely fitted, and slides in a fixed stroke with the reciprocation of the valve stem 2. Is provided, and the chamber 7 is formed by the valve stem seal 3 as in the first embodiment.

The lip portion 6 of the valve stem seal 3 slides on the outer periphery of the valve stem guide 1 at a constant stroke, but the outer diameter a of the valve stem guide 1 above a substantially middle portion of the stroke of the lip portion 6. Is formed slightly smaller than the outer diameter b below it. The step between the small-diameter portion and the large-diameter portion preferably has a smooth curved shape.

In the second embodiment constructed as described above, when the valve stem 2 rises, the volume of the chamber 7 formed by the valve stem seal 3 increases, and a negative pressure is generated in the chamber 7. And at the same time, the lip 6 of the valve stem seal 3 is located at the small diameter portion of the valve stem guide 1, so that a small gap is formed between the lip 6 and the outer periphery of the valve stem guide 1. Oil flows into the chamber 7 at a more negative pressure. In addition, valve stem 2
When the pressure decreases, the volume of the chamber 7 formed by the valve stem seal 3 decreases, and the pressure in the chamber 7 becomes positive. At this time, the lip portion 6 of the valve stem seal 3 The guide 1 slides from the small-diameter portion to the large-diameter portion, and the lip portion 6 comes into contact with the large-diameter portion and becomes closed.
The oil inside is pumped to an oil sump 11 provided below the valve stem guide 1 through a spiral groove 10 formed on the inner periphery of the valve stem guide 1.

As described above, the oil in the chamber 7 formed by the valve stem seal 3 repeatedly flows in and out from the outside by the reciprocating motion of the valve stem 2. An oil film is to be formed.

[0022]

According to the valve stem seal device of the present invention, the base end of the valve stem seal is fitted and fixed to the outer periphery of the valve stem which is slidably and loosely fitted to the cylindrical valve stem guide. The lip protruding downward from the base end is pressed against the outer periphery of the valve stem guide, and the chamber formed by the valve stem seal alternately switches between negative pressure and positive pressure as the valve stem reciprocates. Since oil is caused to flow into and out of the chamber by the generated pressure, an oil film having a sufficient leak amount can always be formed on the outer periphery of the valve stem. Abrasion can be prevented, and there is no fear of an increase in oil consumption or generation of white smoke due to excessive oil supply. Further, in the present invention, the oil that has lubricated the valve stem is provided on the inner periphery of the valve stem guide.
The spiral groove formed in the part and the oil reservoir provided in the lower part of the spiral groove
It is fed to the oil passage through, because they are pumped in one direction through the check valve from the oil passage, in which the cooling effect of the valve stem seal device becomes larger.

[Brief description of the drawings]

FIG. 1 is a sectional view of a valve stem sealing device.

FIG. 2 is a sectional view of a first embodiment for allowing oil to flow into and out of a valve stem seal;

FIG. 3 is a sectional view of a second embodiment for allowing oil to flow into and out of a valve stem seal;

FIG. 4 is a sectional view of a conventional valve stem sealing device.

[Explanation of symbols]

 1 Valve Stem Guide 2 Valve Stem 3 Valve Stem Seal 5 Base End of Valve Stem Seal 6 Lip 8 Through Hole 10 Spiral Groove 12 Oil Passage 13 Check Valve 24 Oil Chamber

Claims (3)

(57) [Claims] A valve stem is slidably and loosely fitted in a cylindrical valve stem guide, a base end of a valve stem seal is fixed to an outer periphery of the valve stem, and is protruded downward from the base end. The lip portion is brought into contact with the outer periphery of the valve stem guide, and a pressure difference is generated in a chamber formed by a valve stem seal with the reciprocation of the valve stem, and the pressure difference causes oil to flow into the chamber. A means for discharging the oil is formed, and the oil is discharged from the valve stem guide.
A spiral groove formed in a peripheral portion and an oil reservoir provided below the spiral groove
Ri feed into the oil passage through the feeds, the valve stem seal device characterized by allowed to pumping to the oil chamber side through the check valve from the oil passage. 2. A means for allowing oil to flow into and out of the chamber formed by the valve stem seal, wherein the valve stem guide has a radial penetration through a position corresponding to a substantially middle portion of a stroke of a lip portion of the valve stem seal. The valve stem sealing device according to claim 1, wherein a hole is formed. 3. A valve stem above a position corresponding to a substantially middle portion of a stroke of a lip portion of a valve stem seal of a valve stem guide as a means for flowing oil into and out of a chamber formed by the valve stem seal. 2. The valve stem sealing device according to claim 1, wherein the outer diameter of the guide is smaller than the outer diameter below the guide.