A gasket structure for an engine exhaust pipe

Abstract

The utility model relates to the technical field of engine exhaust pipe, and disclose a gasket structure for engine exhaust pipe, including the gasket main part, the outer periphery edge of gasket main part and the inner circle of mounting hole are provided with first binding and second binding respectively, and the inner wall of the center hole of gasket main part has the combined sealing rib that butts with the exhaust pipe or cylinder cover gas mouth end face. The utility model discloses through first binding, second binding and the gasket main part edge of wrapping and the inner circle of mounting hole, cooperate the combined sealing rib of center hole, form multiple sealing barriers, utilize stainless steel binding and closely combine exhaust pipe and cylinder cover connecting surface, fill up tiny gap, and the combined sealing rib is further compacted sealing surface through elastic deformation, effectively reduces high temperature gas leakage rate, solves the core problem of insufficient sealing performance.

Description

Technical Field

[0001] This utility model relates to the field of engine exhaust pipe technology, specifically a gasket structure for engine exhaust pipes. Background Technology

[0002] Engine exhaust pipe gaskets are key sealing components in the exhaust system. They are installed between the exhaust pipe and the cylinder head exhaust port. Through the compression deformation of elastic materials (such as graphite, metal, or asbestos-free composite materials), they fill the microscopic unevenness of the connection surface, forming a physical barrier. When high-temperature exhaust gas passes through, the gasket is further compacted under the preload of the bolts and thermal expansion to prevent gas leakage. Its sealing performance depends on the high temperature resistance of the material (usually needing to withstand temperatures above 600°C) and the uniform pressure of the contact surface.

[0003] Most existing engine exhaust pipe gaskets are of traditional design, which has the following shortcomings:

[0004] 1. The connection surfaces between the gasket body edge and the exhaust pipe and cylinder head exhaust port may have tiny gaps due to part machining errors or thermal deformation, resulting in insufficient tightness, reduced sealing performance, and increased high-temperature gas leakage rate.

[0005] 2. Because the edges of the gasket body and the inner circumference of the mounting hole lack edging, the gasket body (such as graphite) may be corroded or oxidized by high-temperature exhaust gas, and may also cause significant mechanical damage during installation and disassembly, resulting in a reduction in the actual service life of the gasket.

[0006] To address the aforementioned issues, this application proposes a gasket structure for an engine exhaust pipe. Utility Model Content

[0007] To address the technical problems existing in the background art, this utility model proposes a gasket structure for engine exhaust pipes.

[0008] The present invention proposes a gasket structure for exhaust pipe of high horsepower natural gas engine, including a gasket body, the outer peripheral edge of the gasket body and the inner peripheral edge of the mounting hole are respectively provided with a first edge and a second edge, and the inner wall of the central hole of the gasket body has a combined sealing rib that connects with the exhaust pipe or cylinder head port end face.

[0009] Addressing the issues of insufficient sealing performance and susceptibility to corrosion from high-temperature exhaust gases in traditional exhaust pipe gaskets, this structure achieves multiple layers of protection through "edge wrapping + combined sealing ribs." The first and second edge wrappings cover the edges and mounting holes, filling tiny gaps caused by processing errors or thermal deformation. The combined sealing ribs further compact the sealing surface through elastic deformation, forming a three-dimensional sealing barrier. The high-temperature gas leakage rate is reduced to below 0.1%. The edge wrapping also prevents the main gasket material, such as graphite, from being oxidized, withstands temperatures above 600℃, avoids edge tearing during installation, and extends the service life to more than twice that of traditional gaskets.

[0010] As a further optimized solution of this utility model, both the first edge and the second edge are made of stainless steel, and the first edge and the second edge are welded and fixed to the main body of the pad. The thickness of the first edge and the second edge is 0.25mm, made of SUS301 (1Cr17Ni7) stainless steel, and fixed to the main body of the pad by brazing.

[0011] SUS301 stainless steel combines corrosion resistance and elasticity. Its 0.25mm thickness reduces weight while maintaining strength, making it 15% lighter than traditional steel edging. The brazing connection (temperature 1050℃) ensures that the bonding strength between the edging and the main body of the pad is ≥50MPa, with no false welds. It will not fall off during thermal cycling (-40℃ to 650℃) and is suitable for high-pressure exhaust conditions (pressure ≤0.5MPa).

[0012] As a further optimized solution of this utility model, the pad body includes a core plate, a first pad, and a second pad arranged sequentially from the inside to the outside. One end of the core plate and the second pad extends outward to form the edge of the pad and is fixed to the first edge. One end of the first pad and the other end of the second pad extend inward to form a combined sealing rib.

[0013] The multi-layer structure design achieves functional layering: the core plate provides an elastic base, the first and second gaskets form sealing ribs, and the edges and edging work together to enhance the overall rigidity. The layered design of the combined sealing ribs makes the compression more uniform and solves the problem of insufficient elasticity of the sealing ribs made of single materials. It is especially suitable for scenarios with flatness deviation between the cylinder head and the exhaust pipe.

[0014] As a further optimized solution of this utility model, there are two first gaskets, which are respectively installed on the upper and lower surfaces of the inner end of the core plate. The inner end of the first gasket has a first inclined rib extending toward the central hole of the main body of the gasket. The free ends of the two first inclined ribs extend downward and are each equipped with a first horizontal rib. The two first horizontal ribs fit together.

[0015] The double first gaskets are symmetrically distributed, and the first inclined rib has an inclination angle of 30°, which can absorb the deformation caused by the installation pre-tightening force (50-100N・m). The first horizontal rib is tightly attached to the sealing surface to form the first sealing defense line. The fitting design ensures that the upper and lower forces are balanced, avoids one-sided leakage, and is suitable for engine vibration conditions.

[0016] As a further optimized solution of this utility model, the first gasket, the first inclined rib and the first horizontal rib are all made of DSN9 stainless steel plate and are integrally formed, with a thickness of 0.25mm and a hardness of (430~490)HV.

[0017] DSN9 stainless steel has a high elastic limit, and the one-piece molding process avoids welding stress, ensuring the consistency of deformation of inclined and horizontal ribs. The 0.25mm thickness is lightweight and can withstand high-frequency thermal cycling without fatigue fracture.

[0018] As a further optimization of this utility model, there are two second gaskets, which are respectively installed and fixed on the outer surface of the two first gaskets. One end of each of the two second gaskets extends outward and forms a gap that matches the core plate. One end of the core plate extends outward and is fixed in the gap between the two second gaskets. The other end of each of the two second gaskets is equipped with a second inclined rib extending toward the center hole of the gasket body. The second inclined rib is opposite to the first inclined rib and a second horizontal rib is installed at its free end. The second horizontal rib is opposite to the adjacent first horizontal rib.

[0019] The second gasket forms a nested structure with the first gasket, and the core plate is embedded in the gap to enhance the overall rigidity. The second inclined rib is inclined in the opposite direction to the first inclined rib at an angle of 30°, forming a "two-way elastic buffer" that can compensate for ±0.2mm of sealing surface displacement. The second horizontal rib is opposite to the first horizontal rib to form a second seal, and the double protection further reduces the risk of leakage.

[0020] As a further optimized solution of this utility model, the second gasket, the second inclined rib, and the second horizontal rib are all made of SUS301 stainless steel plate and are integrally formed.

[0021] SUS301 stainless steel has excellent cold working properties. The integrally formed second inclined rib and second horizontal rib have uniform mechanical properties and an elasticity retention rate of ≥80% at high temperature (600℃), avoiding local embrittlement caused by welding, and is suitable for the continuous high temperature conditions of natural gas engines.

[0022] As a further optimization of this utility model, the horizontal distance between the second horizontal rib and the second gasket is 2mm, and the vertical distance between the second horizontal rib and the second gasket is 0.8mm.

[0023] Precise dimensional design ensures that the second horizontal rib fits perfectly against the sealing surface under pre-tightening force. The horizontal distance of 2mm provides space for the deformation of the inclined rib, and the vertical distance of 0.8mm ensures the strength of the rib and avoids plastic deformation caused by excessive compression (compression rate controlled at 10%).

[0024] As a further optimization of this utility model, the core plate is expanded graphite, and the surfaces of the core plate, the first gasket, and the second gasket all have an HBN high-temperature lubricating coating, which can still maintain its unique stability at high temperatures. The compression rate of the second inclined rib and the second horizontal rib is 10%, and the springback rate is ≥20%.

[0025] Expanded graphite provides excellent sealing and thermal conductivity. The HBN coating remains lubricant (friction coefficient ≤0.1) at 800°C, reducing wear on the sealing surface. A 10% compression ratio ensures a tight fit, and a ≥20% rebound rate compensates for thermal expansion and contraction, maintaining stable sealing pressure during engine start-stop cycles.

[0026] As a further optimized solution of this utility model, the core board, the first gasket, and the second gasket are connected and fixed by arc spot welding through spot welding holes;

[0027] Arc spot welding ensures that the multi-layer structure is free of delamination, and the spot weld holes are filled with sealant to further prevent interlayer leakage. This connection method is lightweight and does not damage the overall elasticity of the gasket, making it suitable for engine environments with frequent vibrations.

[0028] The gasket structure for engine exhaust pipes proposed in this utility model has the following beneficial effects:

[0029] (i) The edging and combined sealing ribs work together to enhance the sealing and leakage prevention capabilities.

[0030] By wrapping the edge of the main body of the pad plate and the inner circumference of the mounting hole with the first and second edging, and in conjunction with the combined sealing ribs of the center hole, multiple sealing barriers are formed. The stainless steel edging is tightly fitted to the connection surface between the exhaust pipe and the cylinder head to fill the tiny gaps. The combined sealing ribs further compact the sealing surface through elastic deformation, effectively reducing the high-temperature gas leakage rate and solving the core problem of insufficient sealing performance.

[0031] (ii) Metal edging protection enhances corrosion resistance and service life.

[0032] The first and second edging are made of SUS301 stainless steel and are fixed to the main body of the pad by brazing. They can withstand temperatures above 600℃ and effectively block the corrosion and oxidation of the core board, such as expanded graphite, by high-temperature exhaust gas. At the same time, the edging enhances the edge strength, which can reduce the mechanical damage rate during installation and disassembly, thereby improving the service life of the pad.

[0033] (iii) Multi-layer gasket structure, adapted to thermal cycling and pressure fluctuations

[0034] The core plate, the first gasket, and the second gasket form a composite structure. The elastic design of the first and second inclined ribs has a compression rate of 10% and a rebound rate of ≥20%, which can absorb the deformation caused by thermal expansion and contraction. For example, in the temperature cycle of engine start-stop, the inclined ribs compensate for the displacement of the sealing surface by bending and stretching, ensuring stable sealing pressure, especially suitable for high exhaust pressure conditions.

[0035] (iv) Integrated positioning and protection simplify assembly and reduce damage.

[0036] The second edge banding also serves a positioning function, preventing the bolt threads from scratching the gasket during assembly. Arc spot welding reinforces the core plate and gasket layer, preventing delamination and detachment. During installation, the edge banding guides the gasket alignment, thereby improving the actual assembly efficiency and preventing damage to the mounting holes caused by bolt thermal expansion.

[0037] (v) High-temperature lubrication coating reduces friction and maintenance costs.

[0038] The HBN high-temperature lubricating coating on the core plate and gasket surface remains stable above 600℃, reducing friction and wear between sealing surfaces and significantly reducing the adhesion rate of gaskets during disassembly. At the same time, the coating enhances corrosion resistance and can withstand trace amounts of acidic substances produced by natural gas combustion, further extending the maintenance cycle.

[0039] (vi) Adapt to various working conditions and enhance equipment versatility

[0040] By adjusting the height and edge thickness of the combined sealing ribs, it can be adapted to the exhaust pipes of high-horsepower natural gas engines with different displacements. The sealing performance is not affected by gas components such as methane and propane. Compared with traditional special gaskets, the equipment versatility is greatly improved, and inventory and replacement costs can be significantly reduced, which is beneficial to the production efficiency of enterprises.

[0041] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0042] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0043] Figure 2 This is a top view of the structure of this utility model;

[0044] Figure 3 This is a cross-sectional structural diagram of the main body of the pad of this utility model;

[0045] Figure 4 This utility model Figure 3 Enlarged structural diagram at point A;

[0046] Figure 5 This is a cross-sectional structural diagram of the second edge of this utility model.

[0047] Figure descriptions: 1. Main body of the pad; 11. Core plate; 12. First gasket; 121. First inclined part; 122. First horizontal part; 13. Second gasket; 131. Second inclined part; 132. Second horizontal part; 2. First edging; 3. Second edging; 4. Combined sealing rib; 5. Spot weld hole. Detailed Implementation

[0048] The embodiments of this utility model are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0049] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0050] See Figures 1-5 A gasket structure for natural gas engine exhaust pipes is disclosed. This gasket structure addresses the sealing requirements of high-horsepower natural gas engine exhaust pipes operating at high temperatures and pressures exceeding 600°C and pressures ≤0.5MPa. It employs a "multi-layer composite + edge protection + combined sealing ribs" design to achieve efficient sealing and long-term durability. The specific implementation method is as follows:

[0051] like Figure 1 , Figure 2 and Figure 5 As shown, the main body 1 of the pad is the core bearing unit. The outer periphery and the inner periphery of the mounting hole are respectively covered and protected by the first edge 2 and the second edge 3. The combined sealing rib 4 of the inner wall of the central hole is tightly fitted with the exhaust pipe or cylinder head port end face to form a triple sealing barrier of "edge-mounting hole-central hole".

[0052] Under the action of bolt preload (50-100 N·m), the combined sealing rib 4 undergoes elastic deformation, filling the micro-unevenness (≤0.2 mm) of the sealing surface. The first edge 2 and the second edge 3 compensate for the gaps caused by part processing errors and thermal deformation. The multi-layer composite structure offsets the effects of thermal expansion and contraction through elastic rebound (rebound rate ≥20%), ensuring that the high-temperature exhaust gas leakage rate is ≤0.1%.

[0053] Specifically, the first edge 2 and the second edge 3 are both made of 0.25mm thick SUS301 stainless steel (1Cr17Ni7), which are cold rolled and then fixed to the pad body 1 by brazing. The first edge wraps around the outer periphery of the pad, and the second edge is embedded in the inner periphery of the mounting hole. The bonding strength between the two and the pad body is ≥50MPa, and there is no detachment during thermal cycling from -40℃ to 650℃.

[0054] Stainless steel edging prevents high-temperature exhaust gases from directly corroding the core board 11 and avoids oxidation of expanding graphite. The rounded corners of the edging edges reduce mechanical damage when tightening bolts.

[0055] like Figure 3 and Figure 4 As shown, the multi-layer composite pad body 1 includes

[0056] Core board 11: uses a density of 1.8 g / cm³ 3 The expanded graphite plate has excellent sealing and thermal conductivity, and the surface is coated with HBN high-temperature lubricating coating (5μm thick). The coefficient of friction is ≤0.1 at 800℃, which reduces wear on the sealing surface.

[0057] First gasket 12: Two DSN9 stainless steel plates (thickness 0.25mm, hardness 430-490HV) are symmetrically attached to the upper and lower surfaces of the core plate. The inner end is integrally formed with a first inclined rib 121 (inclination angle 30°) and a first horizontal rib 122. The two first horizontal ribs are tightly attached to form the first sealing line, which can absorb the deformation caused by the pre-tightening force (maximum deflection 0.3mm).

[0058] Second gasket 13: Two SUS301 stainless steel plates (0.25mm thick) cover the outside of the first gasket, with one end extending outward to form a gap, and the edge of the core plate embedded in it to enhance the overall rigidity. The other end is integrally formed with a second inclined rib 131 (30° inclination angle, opposite to the first inclined rib) and a second horizontal rib 132. The second horizontal rib is 0.5mm away from the first horizontal rib, forming a second seal. The double protection reduces the leakage rate to 1 / 10 of that of traditional gaskets.

[0059] Furthermore, the vertical height difference between the first horizontal rib 122 and the second horizontal rib 132 is 0.8mm, and the horizontal distance is 2mm, ensuring that the sealing surfaces are sequentially fitted during pre-tightening, the contact pressure is evenly distributed, and the sealing surface with a flatness deviation of ≤0.1mm is suitable.

[0060] Furthermore, the elastic deformation range of the first inclined rib 121 and the second inclined rib 131 is 0.1-0.3mm, which can compensate for the displacement of the sealing surface caused by engine start-stop, and the elasticity retention rate is ≥80% after 1000 thermal cycles.

[0061] Specifically, the core board 11, the first gasket 12, and the second gasket 13 are connected by arc spot welding through φ2mm spot welding holes 5. The weld strength is ≥30MPa to prevent interlayer separation. The spot welding holes are filled with high-temperature sealant to further block the interlayer leakage channels.

[0062] It is important to note that when disassembling this gasket structure, the preload must be released first to avoid tearing of the sealing rib due to instantaneous rebound. Before reuse, the integrity of the sealing rib must be checked. The worn areas of the HBN coating need to be recoated. If the mounting hole shows elliptical deformation, the second edge or the entire gasket needs to be replaced to prevent leakage caused by loose bolts.

[0063] In summary, this gasket structure, through multi-layer composite design and precise dimensional control, solves the problems of insufficient sealing performance and susceptibility to high-temperature corrosion of traditional gaskets. It can achieve more than twice the service life in the exhaust pipe sealing of high-horsepower natural gas engines, significantly reducing maintenance costs.

[0064] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A gasket structure for an engine exhaust pipe, comprising a gasket body (1), characterized in that, The outer periphery of the pad body (1) and the inner periphery of the mounting hole are respectively provided with a first edge (2) and a second edge (3). The inner wall of the center hole of the pad body (1) has a combined sealing rib (4) that connects with the exhaust pipe or cylinder head port end face. The pad body (1) includes a core plate (11), a first gasket (12), and a second gasket (13) arranged sequentially from the inside to the outside. One end of the core plate (11) and the second gasket (13) extends outward to form the edge of the gasket and is fixed with the first edge (2). One end of the first gasket (12) and the other end of the second gasket (13) extend inward to form a combined sealing rib (4). There are two first gaskets (12) and they are respectively installed on the upper and lower surfaces of the inner end of the core plate (11). The inner end of the first gasket (12) has a first inclined rib (121) extending toward the center hole of the gasket body (1). The free ends of the two first inclined ribs (121) extend downward and are each equipped with a first horizontal rib (122). The two first horizontal ribs (122) fit together.

2. The gasket structure for an engine exhaust pipe according to claim 1, characterized in that, The first edge band (2) and the second edge band (3) are both made of stainless steel, and the first edge band (2) and the second edge band (3) are welded and fixed to the main body (1) of the pad respectively.

3. The gasket structure for an engine exhaust pipe according to claim 1, characterized in that, The first gasket (12), the first inclined rib (121), and the first horizontal rib (122) are all made of DSN9 stainless steel plate and are integrally formed.

4. A gasket structure for an engine exhaust pipe according to claim 1, characterized in that, There are two second gaskets (13) and they are fixed on the outer surfaces of the two first gaskets (12). One end of each second gasket (13) extends outward and forms a gap that matches the core plate (11). One end of the core plate (11) extends outward and is fixed in the gap between the two second gaskets (13). The other end of each second gasket (13) is equipped with a second inclined rib (131) extending toward the center hole of the pad body (1). The second inclined rib (131) is opposite to the first inclined rib (121) and a second horizontal rib (132) is installed at its free end. The second horizontal rib (132) is opposite to the adjacent first horizontal rib (122).

5. A gasket structure for an engine exhaust pipe according to claim 4, characterized in that, The second gasket (13), the second inclined rib (131), and the second horizontal rib (132) are all made of SUS301 stainless steel plates and are integrally formed.

6. A gasket structure for an engine exhaust pipe according to claim 4, characterized in that, The horizontal distance between the second horizontal rib (132) and the second shim (13) is 2mm, and the vertical distance between the second horizontal rib (132) and the second shim (13) is 0.8mm.

7. A gasket structure for an engine exhaust pipe according to claim 1, characterized in that, The core plate (11) is expanded graphite, and the surfaces of the core plate (11), the first gasket (12), and the second gasket (13) are all coated with HBN high-temperature lubricating coating.

8. A gasket structure for an engine exhaust pipe according to any one of claims 1-7, characterized in that, The core plate (11), the first gasket (12), and the second gasket (13) are connected and fixed by arc spot welding through the spot welding hole (5).

Images