Composite material high-pressure box cover for rail transit vehicles and preparation method and mold thereof

Abstract

The present invention discloses a composite material high-voltage box cover for rail transit vehicles, a preparation method thereof, and a mold. The high-voltage box cover comprises a first glass fiber fabric / resin-based composite material layer, a second glass fiber fabric / resin-based composite material layer, and a foam layer and a strong core felt arranged between the first glass fiber fabric / resin-based composite material layer and the second glass fiber fabric / resin-based composite material layer. The foam layer is arranged inside, and the strong core felt is arranged at the edge. The present invention also comprises a metal piece and a bottom plate pre-placed in the first glass fiber fabric / resin-based composite material layer, and one end of the metal piece is fixed to the bottom plate. The present invention has the characteristics of light weight, integral molding, and stable product size, and also meets the 300kg load-bearing requirement of a traditional aluminum high-voltage box cover.

Description

Technical Field

[0001] The invention belongs to the field of rail transit equipment and relates to a composite material high-voltage box cover for rail transit vehicles and a preparation method and a mold thereof. Background Art

[0002] As the rail transit industry's "low carbon and environmental protection" requirements become increasingly stringent, the lightweighting of vehicles has become imperative. At present, composite materials have successfully achieved lightweight components in vehicle interior decoration parts, while functional parts are still in the early stage of research and development verification. The high-voltage box cover used in traditional rail transit vehicles is made of aluminum materials through welding technology.

[0003] Generally, the traditional aluminum high-voltage box cover is made of 4mm thick aluminum plate. In order to ensure the pressure requirements of the high-voltage box cover, aluminum reinforcement ribs are welded on the high-voltage box cover. The traditional aluminum high-voltage box cover has the following disadvantages:

[0004] (1) The high-voltage box cover is made of aluminum material and is heavy;

[0005] (2) When welding the steel reinforcement ribs on the high-voltage box cover, welding deformation is likely to occur, resulting in installation interface deviation;

[0006] (3) The high-voltage box is made of aluminum material, which is easy to conduct electricity and needs to be insulated later. Summary of the invention

[0007] The technical problem to be solved by the present invention is to solve the problems existing in the above-mentioned prior art and provide a composite material high-voltage box cover for rail transit vehicles, which achieves the characteristics of light weight, integral molding and stable product size, while also meeting the load-bearing requirement of 300kg of traditional aluminum high-voltage box covers, and the product itself is an insulator.

[0008] The invention also provides a method for preparing the composite material high-voltage box cover.

[0009] The invention also provides a mold for preparing a composite material high-pressure box cover.

[0010] The technical solution adopted by the present invention is:

[0011] A composite material high-voltage box cover for rail transit vehicles comprises a first glass fiber fabric / resin-based composite material layer, a second glass fiber fabric / resin-based composite material layer, and a foam layer and a strong core felt arranged between the first glass fiber fabric / resin-based composite material layer and the second glass fiber fabric / resin-based composite material layer, wherein the foam layer is arranged inside, and the strong core felt is arranged at the edge. The invention also comprises a metal part and a bottom plate pre-placed in the first glass fiber fabric / resin-based composite material layer, wherein one end of the metal part is fixed to the bottom plate, and the high-voltage box cover meets the requirement of bearing a load of 300 kg.

[0012] The main body in the middle of the high-voltage box cover adopts a glass fiber foam sandwich structure. In order to meet the requirements of the product installation interface, the installation interface positions around the high-voltage box cover adopt a glass fiber strong core felt sandwich structure, so that the high-voltage box cover meets the product load-bearing requirement of 300kg.

[0013] In order to meet the requirements of the product's external high-voltage equipment interface, a stainless steel metal piece is pre-placed in the first glass fiber layer of the high-voltage box cover. The metal piece has internal threads to provide an installation interface for the external high-voltage equipment. At the same time, the glass fiber layer is wrapped to form an insulation layer between the metal piece and the internal equipment. In order to ensure the strength of the installation interface, a base plate is welded to the bottom of the stainless steel metal piece to prevent the metal piece from rotating under repeated installation, while increasing the tensile strength required by the external equipment for this interface.

[0014] Preferably, the thickness ratio of the first glass fiber fabric / resin-based composite material layer, the foam layer and the second glass fiber fabric / resin-based composite material layer is (1-5): (10-20): (1-5). Further preferably, the thickness ratio is (1-3): (15-20): (1-3). Further preferably, the thickness ratio is 3:15:2. This thickness ratio structure can increase the rigidity of the high-voltage box cover, avoid excessive deformation when bearing weight, and reduce the weight of the product.

[0015] Preferably, the thickness ratio of the first glass fiber fabric / resin-based composite material layer, the strong core felt and the second glass fiber fabric / resin-based composite material layer is (1-5): (8-15): (1-5). Further preferably, the thickness ratio is (1-3): (8-10): (1-3). Further preferably, the thickness ratio is 3:10:2, which can effectively ensure the strength requirements of the installation interface while reducing the weight of the product.

[0016] Another aspect of the present invention relates to a method for preparing the above-mentioned high-voltage box cover, comprising the following steps:

[0017] S1. Set the positioning block at the designated position of the mold body to obtain the mold, clean the mold, and apply a release agent on the mold;

[0018] S2, fix the metal parts inside the positioning block, lay the first glass fiber fabric on the first layer, lay the foam in the center of the second layer, lay the strong core felt on the edge, and lay the second glass fiber fabric on the third layer;

[0019] S3, lay out the auxiliary materials, then seal, and keep the vacuuming interface and the resin injection interface;

[0020] S4, under vacuum conditions, inject the resin through the resin injection interface, and the resin completely penetrates into the first glass fiber fabric, the strong core felt, the foam, and the second glass fiber fabric. After the resin injection is completed, the entire mold is preliminarily heated and cured, and after the preliminarily heated and cured, it is cooled to room temperature;

[0021] S5, performing post-curing molding;

[0022] S6. Remove auxiliary materials and sealing materials, demould and remove the positioning block to obtain the high-pressure box cover.

[0023] Preferably, in S1, movable blocks are arranged on both sides of the mold body, and the edges of the high-pressure box cover after molding are located on the movable blocks. In S6, lifting rings are installed on the movable blocks to lift the lifting rings to demold the high-pressure box cover, thereby solving the problem of damage to the product caused by conventional manual demolding.

[0024] Preferably, in S4, the first glass fiber fabric, the core felt, the foam and the second glass fiber fabric are all laid in the effective area of ​​the mold, so as to reduce the cutting process of the ineffective area after the product leaves the mold.

[0025] Preferably, after the metal piece is fixed inside the positioning block in S2, the other end of the metal piece is fixed to the bottom plate.

[0026] Preferably, the temperature of the initial heating curing is 55-65°C for 5-7 hours, and the post-curing molding is heated at 75-85°C for 1.5-2.5 hours and at 90-100°C for 1.5-2.5 hours.

[0027] Another aspect of the present invention relates to a mold for preparing a composite material high-pressure box cover for rail transit vehicles, characterized in that it includes a mold body, an interface groove is provided in the mold body, a positioning hole is opened in the interface groove, a positioning block is arranged in the positioning hole, and fixing holes are opened on both sides of the mold body, the fixing holes are used to position the movable block, and a lifting ring is fixed on the movable block.

[0028] Preferably, the inner side of the movable block is arranged in a step shape.

[0029] The composite material high-voltage box cover of the present invention is mainly composed of epoxy resin as a matrix material, glass fiber fabric, strong core felt, foam material, and metal parts as reinforcing materials for overall composite molding. Compared with the traditional high-voltage box cover, it has the characteristics of light weight, integral molding and stable product size, and also meets the 300kg load-bearing requirement of the traditional aluminum high-voltage box cover.

[0030] The invention has been successfully tested and tested by finite element analysis software. The product is currently undergoing vehicle verification and no abnormalities have occurred. In actual use, the weight of the high-voltage box cover is effectively reduced, the product size is stable, and the error during installation is reduced.

[0031] The present invention has the following advantages:

[0032] (1) Lightweight, 15% lighter than aluminum high-pressure box cover.

[0033] (2) The product size is stable. The glass fiber composite high-pressure box cover is integrally formed through a composite process, avoiding welding deformation during the original aluminum material forming process.

[0034] (3) The product has its own insulation properties, which can reduce the subsequent insulation treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the planar structure of the high-voltage box cover of the present invention;

[0036] Figure 2 for Figure 1 AA cross-sectional diagram of ;

[0037] Figure 3 for Figure 1 BB cross-sectional diagram;

[0038] Figure 4 for Figure 1 Schematic diagram of CC cross section;

[0039] Figure 5 It is a three-dimensional structural schematic diagram of the high-voltage box cover of the present invention;

[0040] Figure 6 It is a schematic diagram of the planar structure of the mold described in the present invention;

[0041] Figure 7 for Figure 6 Schematic diagram of DD cross section. Specific implementation plan

[0042] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0043] Example

[0044] like Figure 1 , Figure 4 , Figure 5As shown, a composite material high-voltage box cover for rail transit vehicles includes a first glass fiber fabric / resin-based composite material layer 1, a second glass fiber fabric / resin-based composite material layer 2, and a foam layer 3 and a strong core felt 4 arranged between the first glass fiber fabric / resin-based composite material layer 1 and the second glass fiber fabric / resin-based composite material layer 2, wherein the foam layer 3 is arranged inside, and the strong core felt 4 is arranged at the edge, and also includes a metal part 5 and a bottom plate 6 pre-placed in the first glass fiber fabric / resin-based composite material layer 1, and one end of the metal part 5 is fixed to the bottom plate 6. The metal part 5 is made of stainless steel metal parts, and the periphery of the metal part 5 is filled with glass fiber fabric / resin-based composite materials for reinforcement greater than or equal to 50 mm, and no foam shall be filled. The strong core felt 4 is made of a strong core felt composited with polyester and aluminum hydroxide, the foam layer 3 is made of functional PVC foam material, and the metal part 5 is made of stainless steel metal parts.

[0045] like Figure 3 As shown, in order to meet the product's 300kg load-bearing requirement, a glass fiber sandwich structure is used in the middle of the high-voltage box cover. The thicknesses of the first glass fiber fabric / resin-based composite material layer 1, the foam layer 3, and the second glass fiber fabric / resin-based composite material layer 2 are 3mm, 15mm, and 2mm, respectively. This structure can increase the rigidity of the product, avoid excessive deformation when bearing load, and reduce the weight of the product. At the interface of the high-voltage equipment, the metal part 5 is wrapped with glass fiber, and the other side of the bottom plate 6 is the foam layer 3.

[0046] like Figure 2 As shown, in order to meet the requirements of the product installation interface, at the installation interface positions around the high-voltage box cover, the thicknesses of the first glass fiber fabric / resin-based composite material layer 1, the strong core felt 4 and the second glass fiber fabric / resin-based composite material layer 2 are 3mm, 10mm and 2mm respectively, and the glass fiber sandwich structure can effectively ensure the strength requirements of the installation interface while reducing the weight of the product.

[0047] like Figure 6-7 As shown, a mold for preparing a composite material high-voltage box cover for rail transit vehicles includes a mold body 7, an interface groove 8 is provided in the mold body 7, a positioning hole is opened in the interface groove 8, a positioning block 9 is set in the positioning hole, fixing holes 10 are opened on both sides of the mold body 7, a protrusion is provided below the movable block 11, the protrusion is stuck in the fixing hole 10, the fixing hole 10 is used to position the movable block 11, and a lifting ring 12 is fixed on the movable block 11. The inner side of the movable block 11 is set in a step shape, and the effective area 13 of the high-voltage box cover does not exceed the first step of the movable block 11.

[0048] The preparation method of a composite material high-voltage box cover for rail transit vehicles comprises the following steps:

[0049] 1. Mold design and preparation:

[0050] The mold is made of aluminum metal material and processed by a three-axis CNC machining center. In order to ensure the positioning of the threaded interface in the product, 4 independent screw positioning blocks are set at the corresponding positions of the mold to ensure the size of the interface; in order to facilitate the product to be separated from the mold, movable blocks with threaded holes are set on both sides of the mold, and lifting rings can be installed at the threaded holes. The outer area of ​​the movable block does not belong to the effective area of ​​the product, and the inner area of ​​the movable block belongs to the effective area of ​​the product. When the product is separated from the film, the lifting ring can be lifted by the crane to achieve the product separation.

[0051] Mould preparation: first assemble the movable blocks on both sides of the mould onto the main mould, then clean the screw positioning block and the assembled mould with alcohol or acetone, and then apply the release agent on the mould. Apply it more than 3 times, with an interval of 10 minutes each time, and set aside.

[0052] 2. Lamination

[0053] First, tighten the screw positioning block and the stainless steel metal part through threads to ensure that the two fit tightly, then place them in the corresponding position of the mold, and then lay the first layer of glass fiber fabric. Note: When laying, ensure that the stainless steel metal part is covered with glass fiber fabric all around; the glass fiber fabric all around is not allowed to exceed the effective area of ​​the product. Figure 7 13 is the effective area of ​​the product (the previous glass fiber fabrics all need to exceed the effective area of ​​the product to facilitate the product to be separated from the film manually. In this invention, movable blocks for separation from the film are designed on both sides of the mold. Through this design, the damage to the product caused by artificial separation from the film is solved, and the cutting and processing of the ineffective area after the product is separated from the film is reduced). After the first layer of glass fiber fabric is laid, the strong core felt and functional PVC foam material are laid, and finally the second layer of glass fiber fabric is laid. The strong core felt is a strong core felt of polyester + aluminum hydroxide.

[0054] 3. Vacuum bag sealing

[0055] After the raw materials are laid out, the release cloth, isolation film, guide net, guide tube and other auxiliary materials are laid out in sequence. Especially when arranging the guide tube, pay attention to the distance between each guide tube must be guaranteed to be 200mm. Then use sealing strips and vacuum bag film to seal the entire system. During the sealing process, a vacuum extraction interface and a resin injection interface must be retained.

[0056] 4. Resin injection and initial curing

[0057] Under the condition of vacuuming the sealing system, the prepared resin is injected into the sealing system through the reserved resin injection interface. During the entire resin injection process, the resin is ensured to be completely infiltrated into the glass fiber fabric, the strong core felt and the PVC functional foam. After the resin injection is completed, the entire mold is placed in an oven for preliminary heating and curing. The heating is performed at 60°C for 6 hours. After the heating is completed, it is placed in the oven to cool to room temperature.

[0058] 5. Post-curing molding

[0059] After the initial curing is completed, heating is performed at 80℃, 2h / 100℃, 2h.

[0060] 6. Product separation

[0061] Remove the vacuum bag film, sealing strips, demoulding cloth, isolation film, guide net, guide tube and other auxiliary materials, fasten the lifting rings to the movable blocks on both sides of the mold through threads, lift the product from the mold by crane, and finally rotate and remove the screw positioning block to complete the product.

[0062] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a composite material high-voltage box cover for rail transit vehicles, characterized in that: The composite material high-voltage box cover comprises a first glass fiber fabric / resin-based composite material layer (1), a second glass fiber fabric / resin-based composite material layer (2), and a foam layer (3) and a core-strengthening felt (4) arranged between the first glass fiber fabric / resin-based composite material layer (1) and the second glass fiber fabric / resin-based composite material layer (2), wherein the foam layer (3) is arranged inside, and the core-strengthening felt (4) is arranged at the edge, and further comprises a metal piece (5) and a bottom plate (6) pre-placed in the first glass fiber fabric / resin-based composite material layer (1), one end of the metal piece (5) being fixed to the bottom plate (6), and the high-voltage box cover meets the requirement of bearing a load of 300 kg; The preparation method of the composite material high-voltage box cover comprises the following steps: S1. Set the positioning block at the designated position of the mold body to obtain the mold, clean the mold, and apply a release agent on the mold; S2, fix the metal parts inside the positioning block, lay the first glass fiber fabric on the first layer, lay the foam in the center of the second layer, lay the strong core felt on the edge, and lay the second glass fiber fabric on the third layer; S3, lay out the auxiliary materials, then seal, and keep the vacuuming interface and the resin injection interface; S4, under vacuum conditions, inject the resin through the resin injection interface, and the resin completely penetrates into the first glass fiber fabric, the strong core felt, the foam, and the second glass fiber fabric. After the resin injection is completed, the entire mold is preliminarily heated and cured, and after the preliminarily heated and cured, it is cooled to room temperature; S5, performing post-curing molding; S6, remove auxiliary materials and sealing materials, demould and remove the positioning block to obtain the high-pressure box cover; In S1, movable blocks (11) are arranged on both sides of the mold body, and the edges of the high-pressure box cover after molding are located on the movable blocks. In S6, lifting rings are installed on the movable blocks, and the lifting rings are lifted to demould the high-pressure box cover. The inner side of the movable block (11) is arranged in a step shape.

2. The method for preparing a composite material high-pressure box cover according to claim 1, characterized in that: The thickness ratio of the first glass fiber fabric / resin-based composite material layer (1), the foam layer (3) and the second glass fiber fabric / resin-based composite material layer (2) is (1-5):(10-20):(1-5).

3. The method for preparing a composite material high-pressure box cover according to claim 1, characterized in that: The thickness ratio of the first glass fiber fabric / resin-based composite material layer (1), the core felt (4) and the second glass fiber fabric / resin-based composite material layer (2) is (1-5): (8-15): (1-5).

4. The method for preparing a composite material high-pressure box cover according to claim 1, characterized in that: In S4, the first glass fiber fabric, the core felt, the foam and the second glass fiber fabric are all laid in the effective area of ​​the mold.

5. The method for preparing a composite material high-pressure box cover according to claim 1, characterized in that: In S2, after the metal piece is fixed inside the positioning block, the other end of the metal piece is fixed to the bottom plate.

6. The method for preparing a composite material high-voltage box cover according to claim 1, characterized in that: The initial heating curing temperature is 55-65℃, the time is 5-7h, and the post-curing molding is heated at 75-85℃ for 1.5-2.5h and 90-100℃ for 1.5-2.5h.

7. The method for preparing a composite material high-pressure box cover according to claim 1, characterized in that: The composite material high-voltage box cover is made by using a mold, the mold comprising a mold body (7), an interface groove (8) is provided in the mold body (7), a positioning hole is provided in the interface groove (8), a positioning block (9) is provided in the positioning hole, fixing holes (10) are provided on both sides of the mold body (7), the fixing holes (10) are used to position a movable block (11), and a lifting ring (12) is fixed to the movable block (11).

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