Microporous foaming rubber sealing strip with composite structure

Abstract

The microcellular foaming rubber sealing strip of the composite structure comprises an annular sealing strip body of a microcellular foaming structure, one end face of the annular sealing strip body forms a sealing strip compression face, and the other end face of the annular sealing strip body forms a sealing strip installation face. A polyurethane aluminum oxide pad is bonded to the pressed face of the sealing strip, a pressure accumulation buffering groove is formed in the edge of the installation face of the sealing strip, and at least one set of metal net wires are further embedded in the annular sealing strip body. The sealing strip compression face of the annular sealing strip body is provided with the polyurethane aluminum oxide cushion layer, the abrasion resistance of the sealing face can be improved, the polyurethane aluminum oxide cushion layer and the annular sealing strip body are bonded into a whole through the rubber compound transition layer, the stability of the connecting structure is good, and the interface peel strength is high; and the pressure accumulation buffer groove is further formed in the sealing strip mounting surface of the annular sealing strip body, so that transient pressure fluctuation of the sealing strip body can be attenuated through deformation when the annular sealing strip body is stressed, the low leakage rate of the sealing strip is kept to the maximum extent, and practicability is high.

Description

Technical Field

[0001] This utility model relates to the field of sealing technology, specifically to a composite microporous foamed rubber sealing strip. Background Technology

[0002] In the field of industrial sealing, rubber sealing strips are widely used in hydraulic systems, pipeline connections, and mechanical equipment to prevent media leakage and the intrusion of external contaminants. Traditional rubber sealing strips are mainly made of a single rubber material. Although they have a certain degree of elasticity and sealing performance, they are prone to the following technical problems under high pressure, high frequency, or extreme operating conditions:

[0003] (1) Surface is prone to wear and cracking: Under long-term friction and high pressure, the pressure surface of conventional sealing strips is prone to surface cracking and material peeling. Especially in media containing solid particles, the wear rate of the sealing surface can reach 0.2 mm / 100 h, leading to seal failure;

[0004] (2) Poor pressure adaptability: The existing sealing structure lacks a pressure buffering mechanism under pressure fluctuation conditions, such as when the hydraulic system starts and stops. Tests show that when the system pressure exceeds 30MPa instantaneously, the instantaneous leakage rate of traditional O-rings will increase by 15% to 20%.

[0005] (3) Insufficient extrusion resistance: Single rubber materials are prone to plastic deformation under high pressure. Industry data shows that when the working pressure exceeds 45MPa, the extrusion damage rate of sealing strips without reinforcement structure is as high as 60%.

[0006] Therefore, we have made technical improvements to our existing rubber sealing strips, using a composite structure to increase the structural stability of the rubber sealing strips, thereby meeting the usage requirements. Utility Model Content

[0007] The technical problem to be solved by this utility model is to address the shortcomings of the existing technology by providing a microporous foamed rubber sealing strip with a composite structure, which on the one hand can improve the structural strength of the rubber sealing strip and prevent cracking of its stress surface, and on the other hand can make the rubber sealing strip elastic and plastic.

[0008] The technical problem to be solved by this utility model is achieved through the following technical solution: a microporous foamed rubber sealing strip with a composite structure, which includes an annular sealing strip body with a microporous foamed structure, one end face of the annular sealing strip body is formed as the sealing strip pressure surface and the other end face is formed as the sealing strip mounting surface.

[0009] A polyurethane aluminum oxide pad is bonded to the pressure-bearing surface of the sealing strip using a compound adhesive to prevent the pressure-bearing surface of the sealing strip from cracking under pressure.

[0010] A pressure accumulating buffer groove is provided at the edge of the sealing strip mounting surface to accumulate pressure when the sealing strip is under pressure.

[0011] At least one set of metal mesh wires is also embedded between the pressure-bearing surface and the mounting surface of the annular sealing strip body to improve the toughness of the annular sealing strip body. The placement direction of the metal mesh wires is parallel to the two end faces of the annular sealing strip body.

[0012] The technical problem to be solved by this utility model can also be achieved through the following technical solution: the microporous foamed rubber sealing strip with a composite structure described above, wherein the metal mesh wire is arranged in two layers at intervals.

[0013] The technical problem to be solved by this utility model can also be achieved through the following technical solution: the microporous foamed rubber sealing strip with a composite structure described above, wherein the metal mesh wire is a nickel-titanium alloy wire.

[0014] The technical problem to be solved by this utility model can also be achieved through the following technical solution: the microporous foamed rubber sealing strip with a composite structure described above, wherein the width of the metal mesh wire is 75% to 80% of the width of the annular sealing strip body.

[0015] The technical problem to be solved by this utility model can also be achieved through the following technical solution: the microporous foamed rubber sealing strip with composite structure described above, wherein the pressure accumulating buffer groove is an annular groove, the groove depth is 8% to 12% of the thickness of the annular sealing strip body, and the groove width is 15% to 20% of the thickness of the annular sealing strip body.

[0016] The technical problem to be solved by this utility model can also be achieved through the following technical solution: the microporous foamed rubber sealing strip with a composite structure described above, wherein the thickness of the polyurethane alumina pad is 5% to 10% of the thickness of the annular sealing strip body.

[0017] Compared with the prior art, the beneficial technical effects of this utility model are:

[0018] (1) The pressure-bearing surface of the annular sealing strip body has a polyurethane alumina pad, which can improve the wear resistance of the sealing surface. The polyurethane alumina pad is bonded to the annular sealing strip body through the compound rubber transition layer, resulting in good connection structure stability and high interface peel strength. In addition, a pressure accumulating buffer groove is provided on the sealing strip mounting surface of the annular sealing strip body, which can reduce the transient pressure fluctuation of the sealing strip body by deformation when the annular sealing strip body is under pressure, thus maintaining its low leakage rate to the greatest extent and making it highly practical.

[0019] (2) A double-layer metal mesh is embedded in the body of the annular sealing strip. During microporous foaming, the foam can be tightly formed around the double-layer metal mesh, thereby forming a mechanical cohesion. Based on the inherent characteristics of nickel-titanium alloy wire, such as large bending amount, high plasticity, and the ability to recover the initial shape after deformation, the elasticity of the annular sealing strip body is better and the fatigue resistance is stronger. Attached Figure Description

[0020] Figure 1 This is a top view of the structure of this utility model;

[0021] Figure 2 This is a partial cross-sectional view of the present invention from a top-down perspective;

[0022] Figure 3 This is a schematic diagram of the full cross-section of the present invention;

[0023] Figure 4 for Figure 3 A magnified schematic diagram of a portion of the structure.

[0024] In the diagram: 1. Annular sealing strip body; 101. Sealing strip pressure-bearing surface; 102. Sealing strip mounting surface; 2. Polyurethane aluminum oxide pad; 3. Compound rubber; 4. Pressure accumulator buffer tank; 5. Metal mesh. Detailed Implementation

[0025] The specific technical solutions of this utility model are further described below with reference to the accompanying drawings, so as to enable those skilled in the art to further understand this utility model, without constituting a limitation on its rights.

[0026] Example 1, referring to Figure 1-4 A composite microporous foamed rubber sealing strip includes an annular sealing strip body 1 with a microporous foamed structure. The inner and outer diameters of the body 1 can be selected according to the usage requirements. The microporous foamed structure of the annular sealing strip body 1 has a pore diameter of 50~300μm and a closed-cell rate of ≥90%. One end face of the annular sealing strip body 1 is formed as a sealing strip pressure surface 101 and the other end face is formed as a sealing strip mounting surface 102. The sealing strip pressure surface 101 is used to contact the external structure, while the sealing strip mounting surface 102 is used to contact the groove that accommodates the sealing strip.

[0027] A polyurethane alumina pad 2 is bonded to the pressure-bearing surface 101 of the sealing strip by a compound adhesive to prevent the pressure-bearing surface 101 of the sealing strip from cracking under pressure. The thickness of the polyurethane alumina pad 2 is 5% to 10% of the thickness of the annular sealing strip body 1. The compound adhesive is an existing technology and can be a compound adhesive 3 made by mixing hydrogenated nitrile rubber and polyurethane in a ratio of 6:4, and then adding 3wt% silane coupling agent and 1.5wt% dicumyl peroxide.

[0028] To improve the structural stability of the sealing strip under pressure, a pressure accumulating buffer groove 4 is provided at the edge of the sealing strip mounting surface 102. This groove is used to accumulate pressure when the sealing strip pressure surface 101 is under pressure. The pressure accumulating buffer groove 4 is an annular groove with a groove depth of 8% to 12% of the thickness of the annular sealing strip body 1 and a groove width of 15% to 20% of the thickness of the annular sealing strip body 1.

[0029] At least one set of metal mesh wires 5 is also embedded between the sealing strip pressure surface 101 and the sealing strip mounting surface 102 of the annular sealing strip body 1. The diameter of the metal mesh wires 5 can be 0.5mm to 1mm, for example, two layers are arranged vertically to improve the toughness of the annular sealing strip body 1. The placement direction of the metal mesh wires 5 is parallel to the two end faces of the annular sealing strip body 1. The metal mesh wires 5 are nickel-titanium alloy wires. The width of the metal mesh wires 5 is 75% to 80% of the width of the annular sealing strip body 1. The metal mesh wires 5 are arranged in a wavy shape with an amplitude of 0.3 to 0.8mm and a wavelength of 2 to 5mm.

[0030] The composite microporous foamed rubber sealing strip in Example 1 is manufactured as follows:

[0031] (1) Use fiber laser to cut NiTi alloy foil with a thickness of 0.5mm, perform thermomechanical treatment at 400℃, set the martensitic phase transformation temperature Af=65℃, pre-bend it into a wave shape with an amplitude of 0.3mm and a wavelength of 2mm to form a memory metal mesh;

[0032] (2) The EPDM rubber compound containing AC foaming agent is pre-cured at 160℃ and 15MPa for 3 minutes, and then foamed at 170℃ and 5MPa for 8 minutes. When the foaming expansion rate reaches 50%, the pretreated NiTi metal mesh is immediately implanted, and the expansion of the foam body forms a mechanical interlock with the metal mesh wire 5.

[0033] (3) Using a twin-screw co-extrusion process, the compound rubber 3 and 3wt% silane coupling agent are compounded and coated under a temperature gradient of 120℃-170℃, and the extrusion pressure is controlled at 12-15MPa to ensure interface density.

[0034] (4) The outermost polyurethane alumina pad 2 is completed by reaction injection molding (RIM), in which MDI prepolymer and polyether polyol containing 30% nano alumina are mixed at a volume ratio of 1:1.05 and cured in a mold at 80°C.

[0035] (5) Finally, the whole co-sulfurization is carried out at 150°C for 20 minutes to form chemical bonds between the layers. The memory metal mesh recovers the preset waveform after cooling to room temperature, forming a three-dimensional reinforcement structure inside the composite material.

[0036] (6) When it is necessary to reserve a pressure accumulating buffer groove 4 on the sealing strip mounting surface 102, we can use laser etching or mold pre-forming technology to process an annular pressure accumulating buffer groove 4 on the edge of the sealing strip mounting surface 102 before final vulcanization.

[0037] Compared with traditional single-structure sealing strips, the microporous foamed rubber sealing strip with the composite structure described in Example 1 has the following advantages:

[0038] 1. Improved compressive strength: The synergistic effect of the polyurethane alumina pad 2 and the corrugated nickel-titanium alloy mesh reduces the permanent compression deformation of the sealing strip under 50MPa high pressure to below 8% (traditional structure >25%).

[0039] 2. Dynamic sealing optimization: The design of the pressure accumulator buffer tank 4 reduces the starting force by 35% and reduces leakage by 60% when pressure fluctuates;

[0040] 3. Extended service life: The three-layer composite structure enables the wear-resistant life to reach 800,000 reciprocating motions (ISO 3601 test standard), which is 4-5 times that of traditional sealing strips;

[0041] 4. Intelligent adaptability: The shape memory metal mesh automatically adjusts the preload when the temperature changes (the restoring force reaches 15N / mm at 65℃), effectively compensating for differences in material thermal expansion;

[0042] 5. Multifunctional integration: It combines wear resistance (surface hardness 85 Shore D), tear resistance (tear strength > 45kN / m) and shock absorption (damping coefficient 0.25) to provide comprehensive performance, making it highly practical and applicable to a wide range of applications.

Claims

1. A microcellular foamed rubber weatherseal of composite construction characterised in that: It comprises a ring-shaped sealing strip body of microcellular foaming structure, one end surface of the ring-shaped sealing strip body is formed as a sealing strip pressure receiving surface, and the other end surface is formed as a sealing strip mounting surface; A polyurethane aluminum oxide pad is adhered to the sealing strip pressure receiving surface by a mixed rubber, so as to avoid cracking of the sealing strip pressure receiving surface when pressure is received; A pressure accumulation buffer groove is formed at the edge of the sealing strip mounting surface, so as to accumulate pressure when the sealing strip pressure receiving surface receives pressure; At least one set of metal wire meshes is embedded between the sealing strip pressure receiving surface and the sealing strip mounting surface of the ring-shaped sealing strip body, so as to improve the toughness of the ring-shaped sealing strip body, and the placement direction of the metal wire meshes is parallel to the two end surfaces of the ring-shaped sealing strip body.

2. A microcellular foamed rubber weatherseal of composite construction according to claim 1 characterised in that: The metal wire meshes are arranged in two layers in an up-down manner.

3. A microcellular foamed rubber weatherseal of composite construction according to claim 1, characterised in that: The metal wire meshes are made of nickel-titanium alloy wire.

4. A microcellular foamed rubber weatherseal of composite construction according to claim 1, characterised in that: The width of the metal wire meshes is 75% to 80% of the width of the ring-shaped sealing strip body.

5. A microcellular foamed rubber weatherseal of composite construction according to claim 1, characterised in that: The pressure accumulation buffer groove is a ring-shaped groove, the groove depth is 8% to 12% of the thickness of the ring-shaped sealing strip body, and the groove width is 15% to 20% of the thickness of the ring-shaped sealing strip body.

6. A microcellular foamed rubber weatherseal of composite construction according to claim 1, characterised in that: The thickness of the polyurethane aluminum oxide pad is 5% to 10% of the thickness of the ring-shaped sealing strip body.

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