Rubber diaphragm for urea pump

Abstract

The utility model relates to the technical field of rubber diaphragms, in particular to a rubber diaphragm for a urea pump, which comprises a top rubber layer, a first reinforcing layer, an isolating layer, a second reinforcing layer and a bottom rubber layer which are stacked from top to bottom. A metal framework is embedded in the groove, the cross section of the metal framework is in a T shape, the horizontal end of the metal framework is wrapped in the bottom rubber layer, the contradiction between urea corrosion resistance and mechanical strength is solved through combination of the double-material rubber layers, the T-shaped metal framework is combined with the groove wrapping structure, and double insurance of mechanical anchoring and bonding is achieved. The interface stripping under high-pressure alternating load is eliminated, the tensile property and the impact resistance are optimized through the double-layer heterogeneous reinforced fiber layout, the fatigue resistance is remarkably improved, the micropore isolation layer blocks a corrosion medium permeation path, the hidden danger of aging and failure of an interlayer adhesive is reduced, and the dynamic sealing reliability is enhanced through the integrally-formed convex ring.

Description

Technical Field

[0001] This utility model relates to the field of rubber diaphragm technology, and specifically discloses a rubber diaphragm for urea pumps. Background Technology

[0002] The rubber diaphragm used in urea pumps is the core sealing element of automotive selective catalytic reduction (SCR) systems. It typically consists of a rubber body layer, a reinforcing fabric layer, and an internal metal skeleton. Through reciprocating deformation, it achieves high-pressure delivery and sealing isolation of urea solution.

[0003] Existing urea pump diaphragms generally adopt a single-material rubber layer and a single-layer fabric reinforcement structure. Due to the contradiction between the urea corrosion resistance and mechanical strength of rubber materials, swelling and embrittlement are prone to occur when in contact with urea solution for a long time. At the same time, the simple coating structure of traditional skeleton and rubber is prone to interfacial peeling under high pressure alternating load. In addition, the method of bonding dissimilar material layers with adhesives alone poses a risk of aging failure, resulting in insufficient fatigue resistance of the diaphragm and limited sealing life. Utility Model Content

[0004] This invention proposes a rubber diaphragm for urea pumps. By combining two rubber layers, the contradiction between urea corrosion resistance and mechanical strength is resolved. The T-shaped metal frame combined with the grooved covering structure achieves dual protection of mechanical anchoring and adhesion, eliminating interface peeling under high pressure alternating loads.

[0005] This invention is implemented as follows: a rubber diaphragm for a urea pump, comprising:

[0006] The layers are stacked from top to bottom: a top rubber layer, a first reinforcing layer, an insulating layer, a second reinforcing layer, and a bottom rubber layer.

[0007] The lower surface of the bottom rubber layer has an inwardly recessed groove;

[0008] A metal skeleton is embedded inside the groove. The cross-section of the metal skeleton is T-shaped, and its horizontal end is wrapped inside the bottom rubber layer.

[0009] A raised ring is provided on the upper surface of the top rubber layer, and the raised ring is integrally formed with the top rubber layer.

[0010] As a preferred embodiment of the rubber diaphragm for a urea pump according to this utility model, the first reinforcing layer is made of polyester fiber fabric and the second reinforcing layer is made of aramid fiber fabric.

[0011] As a preferred embodiment of the rubber diaphragm for a urea pump according to this invention, the isolation layer is a microporous polytetrafluoroethylene film with a thickness of 0.05-0.2 mm and an average pore size of 5-20 μm.

[0012] As a preferred embodiment of the rubber diaphragm for a urea pump according to this utility model, the vertical section of the metal frame extends to the outside of the groove, and the horizontal section is bonded to the inner wall of the groove by an adhesive.

[0013] As a preferred embodiment of the rubber diaphragm for a urea pump according to this utility model, the top rubber layer, the first reinforcing layer, the isolation layer, the second reinforcing layer, and the bottom rubber layer are all bonded together with each other by an adhesive.

[0014] As a preferred embodiment of the rubber diaphragm for a urea pump according to this invention, the height of the convex ring is 0.5-1.5mm.

[0015] As a preferred embodiment of the rubber diaphragm for a urea pump according to this utility model, the top rubber layer is nitrile rubber and the bottom rubber layer is ethylene propylene diene monomer (EPDM) rubber.

[0016] The beneficial effects of this utility model are:

[0017] This invention resolves the contradiction between urea corrosion resistance and mechanical strength by combining two rubber layers. The T-shaped metal skeleton combined with the grooved covering structure provides dual protection for mechanical anchoring and adhesion, eliminating interfacial delamination under high-pressure alternating loads. The double-layer heterogeneous reinforcing fiber layout optimizes tensile and impact resistance, significantly improving fatigue resistance. The microporous isolation layer blocks the penetration path of corrosive media, reducing the risk of aging and failure of interlayer adhesives. The one-piece molded convex ring enhances the reliability of dynamic sealing. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0019] Figure 1 This is a front sectional view of the overall structure of this utility model;

[0020] Figure 2 This is a top view of the structure of this utility model.

[0021] The markings in the diagram are: 1. Top rubber layer; 2. Bottom rubber layer; 3. First reinforcing layer; 4. Isolation layer; 5. Second reinforcing layer; 6. Metal skeleton; 7. Groove; 8. Raised ring. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments to aid in understanding its content. Unless otherwise specified, the methods used in this invention are conventional methods; the raw materials and apparatus used, unless otherwise specified, are conventional commercially available products.

[0023] Please see Figure 1-2 A rubber diaphragm for a urea pump, comprising:

[0024] The layers are arranged from top to bottom: a top rubber layer 1, a first reinforcing layer 3, an isolation layer 4, a second reinforcing layer 5, and a bottom rubber layer 2.

[0025] The lower surface of the bottom rubber layer 2 has an inwardly recessed groove 7;

[0026] A metal skeleton 6 is embedded inside the groove 7. The cross-section of the metal skeleton 6 is T-shaped, and its horizontal end is wrapped inside the bottom rubber layer 2.

[0027] A raised ring 8 is provided on the upper surface of the top rubber layer 1, and the raised ring 8 is integrally formed with the top rubber layer 1.

[0028] In this embodiment: the rubber diaphragm adopts a double-layer design with a top rubber layer 1 and a bottom rubber layer 2. Nitrile rubber has excellent oil resistance, ensuring a seal on the fuel contact side. EPDM rubber is resistant to urea corrosion and resists swelling of the bottom layer. The groove 7 is embedded with a T-shaped metal skeleton 6, the horizontal section of which is covered by rubber to form a mechanical anchor, and the vertical section is exposed to achieve pump body positioning, eliminating the risk of peeling off the traditional skeleton. The first reinforcing layer 3 made of polyester fiber provides basic tensile strength, and the second reinforcing layer 5 made of aramid fiber reinforces the toughness of the high-pressure area. The double reinforcing layer inhibits fatigue cracking under alternating loads. The isolation layer 4 made of microporous polytetrafluoroethylene blocks urea molecules from penetrating into the gaps between the reinforcing layers, avoiding adhesive aging and failure. The top integrally molded convex ring 8 forms a radial self-tightening seal after compression, improving the reliability of the high-pressure seal.

[0029] As a technical optimization of this utility model, the first reinforcing layer 3 is made of polyester fiber fabric, and the second reinforcing layer 5 is made of aramid fiber fabric.

[0030] In this embodiment: polyester fiber fabric has low cost and good creep resistance, while aramid fiber fabric has high modulus and impact resistance. The two materials complement each other to improve the overall resistance to high pressure deformation.

[0031] As a technical optimization of this utility model, the isolation layer 4 is a microporous polytetrafluoroethylene film with a thickness of 0.05-0.2 mm and an average pore size of 5-20 μm.

[0032] In this embodiment, the microporous polytetrafluoroethylene film utilizes its low surface energy and chemical inertness to prevent adhesive failure caused by interlayer chemical corrosion.

[0033] As a technical optimization of this utility model, the vertical section of the metal frame 6 extends to the outside of the groove 7, and the horizontal section is bonded to the inner wall of the groove 7 by an adhesive.

[0034] In this embodiment: the vertical section of the metal skeleton 6 is exposed to achieve precise positioning, the horizontal section is bonded to the groove 7, and the rubber coating forms a mechanical anchor to disperse alternating stress and avoid interface peeling.

[0035] As a technical optimization of this utility model, the top rubber layer 1, the first reinforcing layer 3, the isolation layer 4, the second reinforcing layer 5 and the bottom rubber layer 2 are all bonded together by an adhesive.

[0036] In this embodiment: the interlayer adhesive bonding ensures the integrity of the laminated structure, and the isolation layer 4 blocks the medium penetration path and avoids the risk of delamination.

[0037] As a technical optimization of this utility model, the height of the convex ring 8 is 0.5-1.5mm.

[0038] In this embodiment: the top integrally formed convex ring 8 forms a radial self-tightening seal after compression, improving the reliability of the high-pressure seal.

[0039] As a technical optimization of this utility model, the top rubber layer 1 is nitrile rubber and the bottom rubber layer 2 is ethylene propylene diene monomer (EPDM) rubber.

[0040] In this embodiment: the top rubber layer 1 is nitrile rubber, and the bottom rubber layer 2 is ethylene propylene diene monomer (EPDM) rubber. Nitrile rubber has excellent oil resistance, ensuring a seal on the fuel contact side, while EPDM rubber is resistant to urea corrosion and resists swelling of the bottom layer.

[0041] The working principle and usage process of this utility model are as follows: The rubber diaphragm adopts a double-layer design with a top rubber layer 1 and a bottom rubber layer 2. Nitrile rubber has excellent oil resistance, ensuring a seal on the fuel contact side. EPDM rubber is resistant to urea corrosion and resists swelling of the bottom layer. The groove 7 is embedded with a T-shaped metal skeleton 6. Its horizontal section is covered by rubber to form a mechanical anchor, and the vertical section is exposed to achieve pump body positioning, eliminating the risk of peeling off the traditional skeleton. The first reinforcing layer 3 made of polyester fiber provides basic tensile strength, and the second reinforcing layer 5 made of aramid fiber strengthens the toughness of the high-pressure area. The double reinforcing layer inhibits fatigue cracking under alternating loads. The isolation layer 4 made of microporous polytetrafluoroethylene blocks urea molecules from penetrating into the gaps between the reinforcing layers, avoiding adhesive aging and failure. The top integrally molded convex ring 8 forms a radial self-tightening seal after compression, improving the reliability of the high-pressure seal.

[0042] In the description of this utility model, it should be understood that the terms "left", "right", "up", "down", "top", "bottom", "front", "back", "inner", "outer", "back", "middle", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0043] However, the above description is only a specific embodiment of this utility model and should not be construed as limiting the scope of implementation of this utility model. Therefore, any substitution of equivalent components or equivalent changes and modifications made in accordance with the scope of protection of this utility model should still fall within the scope of the claims of this utility model.

Claims

1. A rubber diaphragm for a urea pump, characterized in that: include: The layers are stacked from top to bottom: a top rubber layer (1), a first reinforcing layer (3), an isolation layer (4), a second reinforcing layer (5), and a bottom rubber layer (2). The lower surface of the bottom rubber layer (2) is provided with an inwardly recessed groove (7); A metal skeleton (6) is embedded inside the groove (7). The cross-section of the metal skeleton (6) is T-shaped, and its horizontal end is wrapped inside the bottom rubber layer (2). The upper surface of the top rubber layer (1) is provided with a raised ring (8), which is integrally formed with the top rubber layer (1).

2. A rubber diaphragm for a urea pump according to claim 1, characterized in that: The first reinforcing layer (3) is a polyester fiber fabric, and the second reinforcing layer (5) is an aramid fiber fabric.

3. A rubber diaphragm for a urea pump according to claim 1, characterized in that: The isolation layer (4) is a microporous polytetrafluoroethylene film with a thickness of 0.05-0.2 mm and an average pore size of 5-20 μm.

4. A rubber diaphragm for a urea pump according to claim 1, characterized in that: The vertical section of the metal frame (6) extends to the outside of the groove (7), and the horizontal section is bonded to the inner wall of the groove (7) by an adhesive.

5. A rubber diaphragm for a urea pump according to claim 1, characterized in that: The top rubber layer (1), the first reinforcing layer (3), the isolation layer (4), the second reinforcing layer (5), and the bottom rubber layer (2) are all bonded together with each other by an adhesive.

6. A rubber diaphragm for a urea pump according to claim 1, characterized in that: The height of the convex ring (8) is 0.5-1.5mm.

7. A rubber diaphragm for a urea pump according to claim 1, characterized in that: The top rubber layer (1) is nitrile rubber, and the bottom rubber layer (2) is ethylene propylene diene monomer (EPDM) rubber.

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