A seal structure for a gas valve and a gas valve conduit

Abstract

The utility model discloses a kind of sealing structure for air valve and air valve conduit, including cylinder cover, air valve and air valve conduit;Air valve conduit is positioned and installed in the conduit installation hole shaped by cylinder cover, and the guide hole of air valve conduit is slidably arranged with the valve stem body of air valve;Air-tight chamber of annular structure is equipped between air valve conduit and valve stem body, high-pressure gas that can form high-pressure air-tight ring is introduced into air-tight chamber, and the high-pressure gas is supercharged air from fuel engine air intake tank.The utility model uses gas as sealing medium, without additional other sealing material, and has good sealing performance and low maintenance cost.

Description

Technical Field

[0001] This utility model relates to the technical field of engines, and in particular to a sealing structure that can enhance the sealing performance between engine valves and valve guides, specifically a sealing structure for valves and valve guides. Background Technology

[0002] The basic working principle of an engine is to burn fuel in the combustion chamber (S), converting the fuel's chemical energy into heat energy, thereby generating high-temperature, high-pressure combustion gases. As these gases expand, they push the piston, which then performs work through the connecting rod and crankshaft, converting heat energy into mechanical energy. The entire conversion process is completed within the combustion chamber (S), primarily revolving around the four strokes of "intake, compression, power, and exhaust." Figure 1 As can be seen, the combustion chamber S is a cavity formed by the cylinder head 1, cylinder liner 8, piston 9, and valves 2 (which are further divided into exhaust valves and intake valves). The cycle of the four strokes is detailed as follows: Piston 9 moves downward from top dead center (highest point), the intake valve opens, the exhaust valve closes, the pressure in the combustion chamber S decreases, and air is drawn into the combustion chamber S through the intake valve. Then, after piston 9 reaches bottom dead center (lowest point), it moves upward. Both the intake and exhaust valves are closed, and the air in the combustion chamber S is compressed, its volume decreases, and its temperature rises (exceeding the fuel ignition point). When piston 9 approaches top dead center, the injector injects atomized fuel into the combustion chamber S. The fuel mixes with the high-temperature air and quickly ignites, producing high-temperature, high-pressure gas, which pushes piston 9 downward. This gas drives the crankshaft to rotate and output power through the connecting rod. After reaching bottom dead center, piston 9 moves upward again, and at the same time, the exhaust valve opens and the intake valve closes, and the exhaust gas is discharged from the exhaust valve. This cycle repeats continuously.

[0003] In the above process, valve 2 (intake and exhaust valves) acts as a "controllable switch" in the engine combustion chamber, allowing the orderly entry and exit of gases (air / mixture, exhaust gas) through periodic opening and closing; while valve guide 3 guides and supports valve 2. The valve stem 21 of valve 2 and valve guide 3 are in sliding fit, such as... Figure 2 As shown. A proper gap must be maintained between the two. If the gap is too small, the chance of oil entering between the valve stem body 21 and the valve guide 3 decreases, but frictional heat can cause valve 2 to become stuck, preventing it from closing and potentially causing it to collide with the piston 9, leading to engine failure. If the gap is too large, an effective seal cannot be formed, and oil will enter along the excessive gap between the valve stem body 21 and the valve guide 3, causing oil leakage. Oil will then seep into the combustion chamber S along the outer circumference of valve 2, resulting in oil burning and excessive oil consumption.

[0004] Therefore, an appropriate gap needs to be maintained between the air valve 2 and the air valve guide 3. However, this requires extremely high machining precision and has limited sealing effect. Therefore, the common practice is still to leave a gap and then seal it by adding a sealing device. In existing technology, the commonly used sealing methods are mainly O-rings and oil seals. The structure using an O-ring seal is as follows: Figure 3 As shown, the O-ring 71 is installed in the sealing groove inside the valve guide 3, forming axial compression with the valve stem body 21. The material undergoes controllable deformation, and under pressure, it adheres like a "high-viscosity fluid," forming a positive seal. Oil seal covers can be used in two ways, such as... Figure 4 and Figure 5 As shown, one type involves the lip of the oil seal cover 72 being fitted onto the valve stem body 21 and moving up and down with the air valve 2, blocking the oil outside the oil seal cover 72. Another type involves installing an elastic oil seal cover 72 at the upper end of the air valve guide 3, with the lip of the oil seal cover 72 tightened by a spring, forming a "dynamic contact seal" tightly against the surface of the valve stem body 21. However, these commonly used sealing structures all suffer from high installation precision requirements, and the materials are prone to aging, deformation, and oil leakage due to high temperatures, oil contamination, and friction. Therefore, they need to be replaced regularly, and the replacement process is quite labor-intensive. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to provide a sealing structure for gas valves and gas valve conduits that uses gas as a sealing medium, has a good sealing effect, and has low maintenance cost, in light of the current status of the prior art.

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: A sealing structure for a valve and a valve guide includes a cylinder head, a valve, and a valve guide; the valve guide is positioned and installed in a guide mounting hole formed in the cylinder head, and the valve stem body of the valve slides through and cooperates with the guide hole of the valve guide; an annular gas-tight chamber is provided between the valve guide and the valve stem body, and high-pressure gas that can form a high-pressure gas-tight ring is introduced into the gas-tight chamber, the high-pressure gas being pressurized air from the intake box of a fuel engine.

[0007] To optimize the above technical solution, the specific measures also include: The aforementioned air valve conduit has a concave inner ring air groove formed in the guide hole, and the air-tight chamber is formed by the space enclosed by the inner ring air groove and the outer circumferential surface of the valve stem body.

[0008] On the outer circumferential surface of the aforementioned valve conduit, a concave outer ring groove is formed at the position corresponding to the lower part of the inner ring groove, and a radial channel for radially connecting the outer ring groove and the inner ring groove is formed in the valve conduit.

[0009] The cylinder head described above has a supply channel for delivering pressurized air formed at the position corresponding to the outer ring groove.

[0010] The air intake end of the aforementioned supply channel is spirally fitted with a pipe joint, which is connected to the engine's air intake box via an air intake steel pipe.

[0011] Compared with existing technologies, this invention features an annular gas-tight chamber between the valve guide and valve stem of the engine. High-pressure gas is introduced into this chamber, forming a high-pressure gas-tight ring. The high-pressure gas is pressurized air from the intake box of the fuel engine. Under the influence of the pressure difference, the pressurized air flows along the gap between the valve guide and valve stem, preventing oil infiltration and thus achieving a gas-tight seal. This invention uses gas as the sealing medium, eliminating the need for additional sealing materials, resulting in excellent sealing performance and low maintenance costs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of an engine combustion chamber in the prior art; Figure 2 This is a schematic diagram of the assembly structure of the valve stem body and the valve guide of the air valve. Figure 3 This is a schematic diagram of an existing technology that uses O-ring seals; Figure 4 This is one of the schematic diagrams of a structure using an oil seal cover in the prior art; Figure 5 This is the second schematic diagram of a structure using an oil seal cover for sealing in the existing technology; Figures 1 to 5 The attached diagrams are labeled as follows: combustion chamber S, cylinder head 1, valve 2, valve stem body 21, valve guide 3, O-ring 71, oil seal cover 72, cylinder liner 8, and piston 9.

[0013] Figure 6 This is a schematic diagram of the gas-tight structure of this utility model; Figure 7 yes Figure 6 A magnified view of a portion of point I; Figure 8 This is a schematic diagram of the structure of the air valve conduit of this utility model; Figure 9 yes Figure 8 A magnified view of a portion of section II; Figures 6 to 9 The attached diagrams are labeled as follows: cylinder head 1, supply channel 11, valve 2, valve stem body 21, valve guide 3, guide hole 3a, inner ring groove 31, outer ring groove 32, radial channel 33, air seal chamber 4, pipe joint 5, intake steel pipe 6. Detailed Implementation

[0014] The embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0015] Figures 6 to 9 This is a schematic diagram of the structure of this utility model. As shown in the figure, this utility model discloses a sealing structure for a cylinder head and a valve guide, which includes a cylinder head 1, a valve 2, and a valve guide 3. The valve 2 is further divided into an intake valve and an exhaust valve. Figure 6 As shown, the cylinder head 1 has a guide pipe mounting hole, and the valve guide pipe 3 is tightly fitted and inserted into the guide pipe mounting hole of the cylinder head 1. The valve 2 includes a slender valve stem body 21 and a valve seat formed at the bottom of the valve stem body 21. The valve seat can seal and cooperate with the intake and exhaust ports formed in the cylinder head 1. The valve stem body 21 of the valve 2 slides through the guide hole 3a of the valve guide pipe 3, and the valve guide pipe 3 can provide guidance and support for the up and down movement of the valve 2. Figure 7 As shown, the present invention provides an annular gas-tight chamber 4 between the valve conduit 3 and the valve stem body 21. High-pressure gas is introduced into this gas-tight chamber 4, forming a high-pressure gas sealing ring within it, thereby improving the sealing performance between the valve conduit 3 and the valve 2 and preventing oil seepage. The high-pressure gas in this invention is pressurized air from the intake box of a fuel engine.

[0016] This invention proposes a technical solution for achieving a seal between the air valve 2 and the air valve conduit 3 using gas as the sealing medium. This solution abandons the traditional sealing structure that uses O-rings or oil seals, and utilizes the pressure of pressurized air to form an air-sealing ring to achieve the air-sealing effect. The air-sealing principle of this invention is as follows: When the engine is running, the engine's turbocharger draws in air, which is then pressurized by the turbocharger's compressor and cooled by the intercooler before being forced into the engine's intake box. The pressurized air in the intake box is then introduced into the air-sealing chamber 4 through a pipeline, forming a ring-shaped high-pressure air-sealing ring within the air-sealing chamber 4. The high-pressure gas pushes against the entry of engine oil along the gap between the valve stem body 21 and the air valve conduit 3, thereby achieving the air-sealing effect.

[0017] In the embodiments, such as Figure 7 , Figure 8 and Figure 9 As shown, a concave inner ring air groove 31 is formed in the guide hole 3a of the air valve conduit 3 of this utility model. The air-tight chamber 4 mentioned above is formed by the space enclosed by the inner ring air groove 31 and the outer peripheral surface of the valve stem body 21.

[0018] from Figure 9As can be seen, a concave outer ring groove 32 is also formed on the outer circumferential surface of the valve guide 3 of this utility model at the position corresponding to the lower part of the inner ring groove 31. Furthermore, a radial channel 33 is formed in the valve guide 3 for radially connecting the outer ring groove 32 and the inner ring groove 31. In this way, the pressurized air from the engine intake box can enter the airtight chamber 4 through the outer ring groove 32 and the radial channel 33.

[0019] In the embodiments, as shown Figure 6 As shown, the cylinder head 1 of this utility model has a supply channel 11 for conveying pressurized air formed at the position corresponding to the outer ring groove 32.

[0020] The intake end of the supply channel 11 is screwed with a pipe joint 5, which is connected to the intake box of the engine via the intake steel pipe 6.

[0021] This invention utilizes the pressurized air of the engine to achieve sealing. During installation, it is only necessary to connect the air-sealed chamber 4 at the valve stem body 21 to the supply channel 11 of the cylinder head 1. Therefore, installation requirements are low, and no additional sealing materials are needed, eliminating material limitations and the need for periodic replacement. The pressure difference between the inside and outside of the air-sealed chamber ensures close contact with the sealing surface, eliminating friction and preventing frictional resistance in the movement of the valve 2. Overall, the sealing structure of this invention has the following advantages: 1) Low maintenance cost, no need to install additional sealing materials, and no need to replace them regularly; 2) The sealing medium is gas, and the movement of the gas valve has virtually no frictional resistance; 3) Good sealing performance; the pressure difference between the inside and outside of the air chamber allows it to adhere tightly to the sealing surface, effectively preventing oil penetration. 4) The reciprocating speed of the air valve increases with the increase of working conditions, and the pressure of the booster air also increases, which increases the pressure difference in the air-tight chamber, increases the sealing pressure and tightness, so this structure can flexibly adapt to the sealing requirements under different working conditions. 5) The requirements for the clearance between the valve stem and the guide tube are not high, and sealing can be achieved for large clearances and large tolerances; 6) The air chamber structure has a certain degree of elasticity, which can reduce the wear of the air valve and the conduit caused by mechanical vibration and extend their service life; 7) It can compensate for the sealing surface to a certain extent, and the processing accuracy requirements of the sealing surface are relatively low. Even if there is slight unevenness in the sealing surface, the sealing effect can be guaranteed.

[0022] The above embodiments provide a systematic and detailed description of the present utility model. These are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A sealing structure for a valve and a valve guide, comprising a cylinder head (1), a valve (2), and a valve guide (3); wherein the valve guide (3) is positioned and installed in a guide mounting hole formed in the cylinder head (1), and the valve stem body (21) of the valve (2) slides through and cooperates with the guide hole (3a) of the valve guide (3); characterized in that: The valve conduit (3) and the valve stem body (21) are provided with an annular gas-tight chamber (4). High-pressure gas that can form a high-pressure gas-tight ring is introduced into the gas-tight chamber (4). The high-pressure gas is pressurized air from the fuel engine intake box.

2. A sealing structure for a gas valve and a gas valve conduit according to claim 1, characterized in that: The guide hole (3a) of the air valve conduit (3) has a concave inner ring air groove (31) formed in it, and the air-tight chamber (4) is formed by the space enclosed by the inner ring air groove (31) and the outer circumferential surface of the valve stem body (21).

3. A sealing structure for a gas valve and a gas valve conduit according to claim 2, characterized in that: On the outer circumferential surface of the valve conduit (3), a concave outer ring groove (32) is formed at the position corresponding to the lower part of the inner ring groove (31), and a radial channel (33) for radially connecting the outer ring groove (32) and the inner ring groove (31) is formed in the valve conduit (3).

4. A sealing structure for a gas valve and a gas valve conduit according to claim 3, characterized in that: The cylinder head (1) has a supply channel (11) for delivering pressurized air at the position corresponding to the outer ring groove (32).

5. A sealing structure for a gas valve and a gas valve conduit according to claim 4, characterized in that: The air intake end of the supply channel (11) is spirally fitted with a pipe joint (5), which is connected to the air intake box of the engine via an air intake steel pipe (6).

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