JPH04134607U - Seal for valve stem - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a valve stem seal that can maintain sealing performance regardless of pressure fluctuations and temperature changes in a mixed gas chamber. [Structure] One end side of a cylindrical guide 2 is arranged facing the mixed gas chamber 5, and the valve stem 4 is inserted into the guide 2 so as to be able to reciprocate, and at a position facing the mixed gas chamber 5.
A resin seal ring 23 that contacts the outer periphery of the valve stem 4 is provided to seal engine oil supplied from the other end of the guide 2 to the sliding surface between the guide 2 and the valve stem 4. A rubber-like elastic packing 15 having an inner diameter smaller than the outer diameter of the resin seal ring 23 is attached to the outer periphery of the ring 2, and blocking members 9 and 22 prevent contact between the packing 15 and engine oil. has been established.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea is based on valves used in the intake and exhaust systems of automobile engines, for example. Regarding the sticker for the system.

0002

[Conventional technology]

FIG. 3 shows a conventional valve stem seal of this type. to cylinder head 100 A cylindrical guide 101 is provided along the vertical direction, and inside this guide 101 A valve stem 103 having a head 102 is inserted into the valve stem 103 so as to be able to reciprocate. Ma In addition, between the guide 101 and the valve stem 103, a variable pressure fluid (high temperature mixed A rubber-like elastic packing 105 is provided at a position facing the gas chamber 104.

0003 In the above configuration, the valve stem 103 reciprocates and engages the variable pressure fluid chamber 104 and the combustion chamber. A port 107 connecting to the chamber 106 is opened and closed. In addition, this operating guide 1 Lubricating oil (engine oil) is supplied from the top between 01 and valve stem 103. and lubricates its sliding surfaces. In addition, the packing 105 is is prevented from leaking to the variable pressure fluid chamber 104 side.

0004 Here, the packing 105 is placed at the lowest part of the guide 101, that is, in the variable pressure fluid chamber 104. The lubricating oil is placed closer to the sliding surface to supply lubricating oil evenly to the sliding surfaces and to reduce the amount of leakage. By minimizing the amount of deposits generated on the valve stem 103, etc. This is for the purpose of Note that the packing 105 is formed of a resin alone in addition to a rubber-like elastic material. Sometimes.

[0005]

[Problem that the idea aims to solve]

However, in the above conventional example in which the packing 105 is made of a rubber-like elastic body, teeth, Pressure fluctuations (positive pressure to negative pressure) in the variable pressure fluid chamber 104 due to opening and closing of the port 107 are The packing 105 receives this directly and is elastically deformed.

[0006] The vulcanized rubber constituting the packing 105 is exposed to a variable pressure fluid, that is, a high-temperature mixed gas. Contact causes deterioration (decreased elasticity, etc.).

[0007] Due to these two reasons, the sealing performance of the packing 105 deteriorates, causing the lubricating oil to flow under variable pressure. There was a risk that a large amount would leak into the body chamber 104 or the combustion chamber 106.

[0008] Also, if the packing 105 is made of a single resin, it will be more rigid than a rubber-like elastic material. Although the above problem does not occur because it is high and can withstand high temperature and high pressure, Due to poor adhesion to the valve stem, the sealing performance inevitably deteriorates.

[0009] This idea was developed to solve the above problem, and prevents lubricating oil from leaking into the variable pressure fluid chamber. It is possible to prevent the pressure fluctuations and temperature changes of the variable pressure fluid in the variable pressure fluid chamber. The purpose is to provide a valve stem seal that can ensure sealing performance without any Ru.

0010

[Means to solve the problem]

In order to achieve the above purpose, this invention has one end side of the cylindrical guide facing the variable pressure fluid chamber. Insert the valve stem into this guide so that it can reciprocate, and Slide the guide and valve stem from the other end of the guide in a position facing the pressure fluid chamber. Made of resin that contacts the outer periphery of the valve stem to seal the lubricating oil supplied to the surface. A seal ring is provided on the outer periphery of the resin seal ring. Attach a rubber-like elastic packing with an inner diameter smaller than the A blocking member is provided to prevent contact between the packing and the variable pressure fluid.

[0011]

[Effect]

The diameter of the resin seal ring is reduced by the elastic force of the rubber-like elastic packing, and the band is closed. The contact pressure of the resin seal ring against the lubstem increases. In addition, the blocking member Prevent the packing from contact with variable pressure fluid.

0012

【Example】

Next, an embodiment of this invention will be described based on the drawings. Figure 2 shows how this idea can be applied to a car. This figure shows an example of use in the intake/exhaust system of a commercial engine. to cylinder head 1 A cylindrical guide 2 is provided along the vertical direction, and one end (lower side) of the guide 2 is It faces the pressurized fluid (high temperature, high pressure gasoline mixed gas) chamber 5. This guide 2 A valve stem 4 having a head 3 is inserted into the stem hole 7 so as to be able to reciprocate. Also, between the guide 2 and the valve stem 4, the lower side, that is, the area where the mixed gas passes A valve stem seal 6 is provided at a position facing the pressure fluid chamber 5.

[0013] FIG. 1 is an enlarged sectional view of the valve stem seal 6. As shown in FIG. Below the valve guide 2 A fitting hole 8 is provided which is concentric with the stem hole 7 and has a larger diameter than the stem hole 7. child The fitting hole 8 and stem hole 7 are formed after the valve guide 2 is assembled to the cylinder head 1. It is processed into.

[0014] A metal retaining ring 9 is fitted and fixed to the inner periphery of the fitting hole 8. this The retaining ring 9 has a small diameter portion 10 fitted to the inner periphery of the fitting hole 8 and one end side of the small diameter portion 10, i.e. , an outward flange 11 formed on the side of the variable pressure fluid chamber 5, and an outer peripheral end of the flange 11. The connected large diameter portion 12 and the annular stopper 1 formed inward at one end of the large diameter portion 12. 3.

[0015] The flange portion 11 is in close contact with the lower end surface 14 of the valve guide 2, and the large diameter portion 12 is in close contact with the lower end surface 14 of the valve guide 2. It is set to have a larger diameter than the small diameter portion 10 and approximately the same outer diameter as the outer diameter of the valve guide 2. be.

[0016] The inner periphery of the large diameter portion 12 is made of rubber-like elastic material (nitrile rubber, acrylic rubber, silicone A packing 15 made of rubber, etc.) is attached. The outer peripheral surface 16 of this packing 15 is large. While the side surfaces 17 and 18 are in close contact with the inner periphery of the diameter portion 12, the flange portion 11 and the stock They are closely following Pa13. In addition, the inner periphery of the packing 15 is provided with an inwardly protruding portion. An annular pressure applying portion 19 is formed.

[0017] Further, the packing 15 is baked and bonded to a metal ring 20 having an L-shaped cross section. The metal ring 20 includes a cylindrical portion 21 and an inward flange 22. When the ring 22 contacts the stopper 13 of the retaining ring 9, the packing 15 is positioned in the axial direction. It is fixed.

[0018] The inner diameter of the inward flange 22 of the metal ring 20 is equal to the pressure applying part 1 of the packing 15. Set the inner diameter to be smaller than the inner diameter of valve stem 4 and not contact the valve stem 4. There is.

[0019] A seal ring made of resin (tetrafluoroethylene resin, etc.) is provided on the inner peripheral side of the packing 15. A ring 23 is attached. The inner diameter of the pressure applying portion 19 is sealed with a resin seal. It is set smaller than the outer diameter of the ring 23. The retaining ring 9 and the metal ring 20 are This is a blocking member in the patented invention, and allows the variable pressure fluid in the variable pressure fluid chamber 5 to come into contact with the packing 15. Prevents touching.

[0020] Note that the variable pressure fluid chamber 5 communicates with a combustion chamber 25 via a port 24.

[0021] Next, the operation of the above embodiment will be explained. The valve stem 4 reciprocates to open the port 24. opens and closes to intake and exhaust the mixed gas. Also, during this operation, the stem hole 7 Lubricating oil (engine oil) is supplied from the top to the guide 2 and valve stem 4. Lubricate the sliding surfaces.

[0022] In addition, the elastic force of the pressure applying portion 19 of the packing 15 causes the resin seal ring 2 to 3 is reduced in diameter, and the adhesion of the sealing surface 26 to the valve stem 4, that is, the contact pressure is improving. Therefore, the lubricating oil can be prevented from leaking into the variable pressure fluid chamber 5. .

[0023] Additionally, the pressure of the mixed gas in the variable pressure fluid chamber 5 fluctuates as the port 11 opens and closes. (Positive pressure to negative pressure) Then, this pressure fluctuation occurs between the resin seal ring 23 and the stem 4. It is applied in the axial direction to the end surface 26a of the packing 9 from between. However, the resin seal Since the ring 23 has high rigidity, it does not deform due to pressure fluctuations, and the sealing surface 26 Sealing performance can be ensured. In addition, it is not easily deformed even at high temperatures, ensuring sealing performance. can.

[0024] Furthermore, since the variable pressure fluid is blocked by the retaining ring 9 and the metal ring 20, the packing 15 Do not come into contact with. Therefore, the packing 15 is not deteriorated by the mixed gas, Has a stable elastic force imparting function.

[0025] In the above configuration, the outer diameter of the valve stem 4 is set to about 6 mm, and the outer diameter of the guide 2 is set to about 6 mm. It is set to about 10mm. In this way, the outer diameter of the guide 2 is set thin, and the retaining ring 9 is configured to fit into the inner circumference of the fitting hole 8 of the guide 2, since the mixture inside the variable pressure fluid chamber 5 is This is to prevent the flow of the combined gas from being disturbed as much as possible.

[0026] Furthermore, the packing 11 and the resin seal ring 23 are aligned to the inner circumference of the retaining ring 9. Since they are physically combined, just by fitting the retaining ring 9 into the stem hole 8, the guide 2 can be attached. installation can be completed. Therefore, the installation workability is also good.

[0027]

[Effect of the idea]

Since this device is constructed as described above, it is possible to prevent lubricant oil from leaking. Of course, the sealing performance of the seal surface is maintained regardless of pressure fluctuations and temperature changes in the variable pressure fluid chamber. can be maintained.

[Brief explanation of drawings]

FIG. 1 is a half-sectional view showing the main parts of an embodiment in which the present invention is applied to an intake/exhaust system of an automobile engine.

FIG. 2 is a sectional view showing the overall configuration of FIG. 1.

FIG. 3 is a sectional view showing the configuration of a valve stem seal used in the intake/exhaust system of a conventional automobile engine.

[Explanation of symbols]

1 cylinder head 2 Guide 3 head 4 Valve stem 5 Variable pressure fluid chamber 6 Valve stem seal 7 Stem hole 8 Fitting hole 9 Retaining ring 10 Small diameter part 11 Flange part 12 Large diameter part 13 Stopper 14 Lower end surface 15 Packing 16 Outer surface 17,18 Side 19 Pressure applying section 20 Metal ring 21 Cylindrical part 22 Inward flange 23 Resin seal ring 24 ports 25 Combustion chamber 26 Seal surface 26a End face

Claims (1)

[Scope of utility model registration request] Claim 1: One end of a cylindrical guide is placed facing a variable pressure fluid chamber, a valve stem is inserted into the guide so as to be able to reciprocate, and the other end of the guide is placed in a position facing the variable pressure fluid chamber. A resin seal ring is provided that contacts the outer periphery of the valve stem in order to seal the lubricating oil supplied to the sliding surfaces between the guide and the valve stem. A seal for a valve stem, which is equipped with a packing made of a rubber-like elastic body having an inner diameter smaller than the outer diameter, and is provided with a blocking member that prevents contact between the packing and a variable pressure fluid.