阅读说明：本技术 一种预埋金属螺母复合材料箱体的rtm成型模具及方法 (RTM (resin transfer molding) forming die and method for embedded metal nut composite material box ) 是由 韩霞 程浩 王微 王亚飞 张凯 华继凡 于 2020-11-26 设计创作，主要内容包括：本发明公开了一种预埋金属螺母复合材料箱体的RTM成型模具,包括阴模、阳模以及螺栓,阴模上设置有注胶口、出胶口及螺纹孔,阳模上依次铺放有下层纤维织物、复合材料板和上层纤维织物,复合材料板上嵌套有多组金属螺母,上层纤维织物包覆复合材料板并预留螺母容置孔,螺栓依次穿过阴模的螺纹孔、上层纤维织物的螺母容置孔后旋入金属螺母,还公开了其RTM一体成型工艺；本发明制造的复合材料箱体自带有金属螺母,能够稳定的安装于其它设备上,有效避免复合材料打孔造成的结构和力学损伤,保证复合材料箱体的密封性能,可以实现复合材料箱体与金属结构或其他设备的连接固定,稳定性更好,箱体密封性优异。(The invention discloses an RTM forming die of a pre-embedded metal nut composite material box body, which comprises a female die, a male die and a bolt, wherein the female die is provided with a glue injection port, a glue outlet and a threaded hole, the male die is sequentially paved with a lower layer fiber fabric, a composite material plate and an upper layer fiber fabric, a plurality of groups of metal nuts are nested on the composite material plate, the upper layer fiber fabric coats the composite material plate and is reserved with nut accommodating holes, and the bolt sequentially passes through the threaded hole of the female die and the nut accommodating holes of the upper layer fiber fabric and then is screwed into a metal nut; the composite material box body manufactured by the invention is provided with the metal nut, can be stably installed on other equipment, effectively avoids structural and mechanical damages caused by punching of the composite material, ensures the sealing performance of the composite material box body, can realize the connection and fixation of the composite material box body and the metal structure or other equipment, and has better stability and excellent box body sealing performance.)

1. The utility model provides a RTM forming die of pre-buried metal nut combined material box which characterized in that: the mold comprises a female mold (7) and a male mold (1) which can form a closed mold cavity after mold assembly, and a connecting bolt (9), wherein the female mold (7) is provided with a glue injection port used for connecting an injection machine, a glue outlet used for connecting a resin pipe of vacuum equipment, and a plurality of threaded holes (8), the male mold (1) is sequentially paved with a lower layer fiber fabric (5), a composite plate (4) and an upper layer fiber fabric (6), the composite plate (4) is nested with a plurality of groups of metal nuts (3) which are just opposite to the threaded holes (8), the upper layer fiber fabric (6) coats the composite plate (4) and reserves a nut containing hole, the thickness of the composite plate (4) is smaller than that of the metal nuts (3), and the bolt (9) is screwed into the metal nuts (3) after sequentially penetrating through the threaded holes (8) and the nut containing hole.

2. The RTM forming die for the embedded metal nut composite box body as claimed in claim 1, wherein the metal nuts (3) are stainless steel flange nuts completely embedded in the composite box body, and the number of the metal nuts is 4-6.

3. An RTM forming method of an embedded metal nut composite material box body is based on the forming die of claim 1, and is characterized by comprising the following steps:

step 1, carving a cavity on a composite material plate (4), and embedding a plurality of groups of metal nuts (3) into the composite material plate (4);

step 2, respectively layering a lower layer fiber fabric (5) and an upper layer fiber fabric (6) on two lower sides of the composite material plate (4);

step 3, laying a lower layer of fiber fabric (5) on the male die (1), coating the composite material plate (4) with an upper layer of fiber fabric (6), reserving a nut accommodating hole in the upper layer of fiber fabric (6), and aligning the nut accommodating hole with the metal nut (3);

step 4, placing a female die (7) above the upper-layer fiber fabric (6), aligning a threaded hole (8) with a nut accommodating hole and a metal nut (3) and fixing the threaded hole and the nut accommodating hole through a bolt (9) to form a die set I;

and 5, selecting N sets of first mold sets and 5-N sets of second mold sets which are only composed of female molds (7) and male molds (1) to assemble the molds, injecting fiber reinforced resin matrix composite materials into the closed mold cavity through an injection machine, and preparing the composite material box body (10) with N embedded metal nut panels and 5-N top openings without the metal nut panels through an RTM (resin transfer molding) process, wherein N =1, 2, 3, 4 or 5.

4. The RTM forming method of the embedded metal nut composite material box body according to claim 3, wherein the fibers are glass fiber fabrics or/and carbon fiber fabrics.

5. The RTM forming method of the embedded metal nut composite material box body according to claim 4, wherein the resin is unsaturated resin, vinyl resin or epoxy resin.

Technical Field

The invention belongs to the technical field of integrated molding of resin-based composite materials and metal parts, and particularly relates to an RTM (resin transfer molding) molding die and an integrated molding method for a composite material box body with multiple groups of embedded metal nuts.

Background

Compared with the traditional lightweight material, the high-performance fiber reinforced resin matrix composite material has the advantages of small density, high strength, high modulus and the like, and is widely applied to lightweight design in rail transit equipment.

The RTM process is a process in which a low viscosity resin flows between a closed male and female mold, and is impregnated with a reinforcing material and cured. With the development of composite material technology, the RTM process is widely used for producing larger regular parts, the RTM process is low in cost and environmentally friendly, and larger parts such as composite material water tanks, containers and the like are also gradually applied to ships and vehicles.

Because the structure and the mechanics damage are easily caused by punching the composite material structural part, the sealing performance of the composite material box body is damaged, the composite material box body is difficult to be connected and fixed with other equipment, and the composite material box body is easy to shake and topple over during the driving process, so that potential safety hazards are generated.

Therefore, when the composite material box body with the embedded multiple groups of metal nuts is subjected to RTM (resin transfer molding) integrated molding, the molding failure is easily caused.

Disclosure of Invention

In order to overcome the technical defects, the invention provides an RTM (resin transfer molding) mold for a composite material box with embedded sets of metal nuts.

The technical scheme adopted by the invention for solving the technical problems is as follows: an RTM forming die of a pre-embedded metal nut composite material box body comprises a female die and a male die which can form a closed die cavity after die assembly and a connecting bolt, wherein a glue injection port for connecting an injection machine, a glue outlet for connecting a resin pipe of vacuum equipment and a plurality of threaded holes are formed in the female die, the injection machine injects resin into the closed die cavity and then solidifies and forms the composite material box body, a lower layer of fiber fabric, a middle composite material plate and an upper layer of fiber fabric are sequentially paved on the male die, a plurality of groups of metal nuts which are right opposite to the threaded holes are nested on the composite material plate, the upper layer of fiber fabric coats the composite material plate and reserves nut containing holes, the positions of the upper layer of fiber fabric and the metal nuts of the composite material plate are consistent, the composite material plate is positioned and fixed with the female die through the bolt, the RTM of the composite material plate is formed, the thickness of the, and a plurality of groups of metal nuts are embedded into the composite plate according to design positions, and the bolts sequentially penetrate through the threaded holes of the female die and the nut accommodating holes of the upper layer of the fiber fabric and are screwed into the metal nuts to ensure the vacuum degree after die assembly.

The RTM forming die for the pre-embedded metal nut composite material box body is characterized in that a metal nut is a standard stainless steel flange nut which is completely embedded into the composite material box body, the threaded end of the nut is flush with the surface of the box body, and the number of the metal nuts is not limited.

The invention also aims to provide a method for performing RTM (resin transfer molding) integrated molding on the embedded metal nut composite material box body based on the molding die, so that the technical problems that the composite material box body is difficult to connect and fix and easy to shake and topple in the prior art are solved, the structural and mechanical damage caused by punching of the composite material is effectively avoided, and the sealing performance of the composite material box body is ensured.

The technical scheme adopted by the invention for solving the technical problems is as follows: an RTM forming method of a pre-embedded metal nut composite material box body comprises the following steps:

step 1, embedding a plurality of groups of metal nuts on an intermediate composite material plate: RTM (resin transfer molding) molding of the composite material plate, wherein the thickness of the RTM molding is smaller than that of the nut, a cavity is carved on the composite material plate according to the external dimension of the nut, and a plurality of groups of metal nuts are embedded into the composite material plate according to the designed positions;

step 2, respectively layering a lower layer fiber fabric and an upper layer fiber fabric on the two lower sides of the composite material plate;

step 3, directly laying the lower layer of fiber fabric on the male die, coating the composite material plate with the upper layer of fiber fabric, reserving a nut accommodating hole in the upper layer of fiber fabric, and aligning the nut accommodating hole with the metal nut;

step 4, placing the female die above the upper-layer fiber fabric, aligning the threaded hole with the nut accommodating hole and the metal nut, and fixing the threaded hole, the nut accommodating hole and the metal nut through bolts to form a die set I;

and 5, combining the N sets of the first mold sets and 5-N sets of the second mold sets which are only composed of female molds and male molds, injecting fiber reinforced resin matrix composite materials into the closed mold cavity through an injection machine, and preparing the composite material box body which is provided with N pre-embedded metal nut panels and 5-N composite material box bodies without the metal nut panels and provided with openings at the tops through an RTM (resin transfer molding) process, wherein N =1, 2, 3, 4 or 5.

Furthermore, the fiber is glass fiber fabric or/and carbon fiber fabric.

Further, the resin is unsaturated resin, vinyl resin or epoxy resin.

Compared with the prior art, the invention has the beneficial effects that: the composite material box body prepared by the forming die disclosed by the invention is provided with the metal nut, so that the composite material box body can be connected and fixed with a metal structure or other equipment, can be stably arranged on other equipment, effectively avoids structural and mechanical damages caused by punching of a composite material, ensures the sealing performance of the composite material box body, and is better in stability.

The RTM molding process adopted by the invention realizes the positioning of the metal nut inserts and the integrated molding process of the composite material box body with the embedded multiple groups of metal nuts through the design of the RTM mold, has low RTM integrated molding process cost and small pollution to workshop environment, can meet the increasingly strict requirements of environmental protection laws and regulations, and can provide composite material parts with excellent performance.

Compared with a metal box body, the composite material box body not only ensures the structural strength of the box body, but also reduces the weight. Meanwhile, the composite material box body is connected with other metal parts, can be stably installed on other equipment, can effectively avoid structural and mechanical damages caused by punching of the composite material, and ensures the sealing performance of the composite material box body. The composite material box body is applied to a ship-borne or vehicle-borne water tank or container, and the position of the box body can be fixed through bolts, so that the box body is prevented from moving or toppling due to shaking or vibration.

Drawings

FIG. 1 is a schematic structural view of a forming die of the present invention;

FIG. 2 is a structural diagram of a composite material box formed by the method of the present invention.

The figures are numbered: the manufacturing method comprises the following steps of 1-male die, 2-side wall or bottom, 3-metal nut, 4-composite material plate, 5-lower layer fiber fabric, 6-upper layer fiber fabric, 7-female die, 8-threaded hole, 9-bolt and 10-composite material box body.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

As shown in figure 1, the RTM forming die of the pre-embedded metal nut composite material box body disclosed by the invention comprises a female die 7 and a male die 1 which can form a closed die cavity after die assembly and a connecting bolt 9, wherein a glue injection port for connecting an injection machine, a glue outlet for connecting a resin pipe of vacuum equipment and a threaded hole 8 are arranged on the female die 7, the injection machine injects resin into the closed die cavity and then solidifies and forms a composite material box body 10, a lower layer fiber fabric 5, a middle composite material plate 4 and an upper layer fiber fabric 6 are sequentially laid on the male die 1, a plurality of groups of metal nuts 3 which are right opposite to the threaded hole 8 are nested on the composite material plate 4, the upper layer fiber fabric 6 coats the composite material plate 4 and reserves nut containing holes, the positions are consistent with those of the metal nuts 3 of the composite material plate 4, and are positioned and fixed with the female die 7 through the bolt 9, the composite material plate 4 is formed by RTM, the material is the same as the box body, the thickness of the composite material plate is smaller than that of the metal nuts 3, the composite material plate 4 and a panel of the box body are integrally formed after injection molding, the outer size of the nuts is carved on the composite material plate 4, a plurality of groups of metal nuts 3 are embedded into the composite material plate 4 according to design positions, and the bolts 9 sequentially penetrate through threaded holes 8 of the female die 7 and nut accommodating holes of the upper layer of fiber fabric 6 and then are screwed into the metal nuts 3 to ensure the vacuum degree after die assembly. Wherein metal nut 3 is the standard stainless steel flange nut of embedding in the combined material box 10 completely, need imbed the box panel completely after the shaping, and nut thread end and panel surface parallel and level, 3 quantity of metal nut are 4 ~ 6.

The embodiment 1 of the invention provides a glass fiber reinforced plastic storage battery groove with a plurality of groups of embedded metal nuts, and the integrated molding process of the glass fiber reinforced plastic storage battery groove with the plurality of groups of embedded metal nuts is an RTM (resin transfer molding) liquid process. The glass fiber reinforced plastic storage battery tank is used for storing electrolyte and electrodes, and the metal nut is used for fixing the position of the storage battery tank, so that the storage battery tank is prevented from moving or toppling over due to shaking or vibration. The RTM liquid forming process comprises a mold design and a metal nut embedding scheme. The glass fiber reinforced plastic storage battery tank with the embedded groups of metal nuts is made of fiber reinforced resin matrix composite materials, and the reinforced fibers comprise glass fiber fabrics; the resin is modified epoxy resin.

The middle composite plate 4 is nested with the metal nut 3, the composite plate 4 is formed by vacuum pressure molding, the reinforcing fiber is glass fiber fabric, and the resin is modified epoxy resin. And (3) closing the female die 7 and the male die 1 to form a closed die cavity, mixing the modified epoxy resin into a curing agent by an injection machine, injecting into the closed die cavity, and curing and molding.

Example 2

The embodiment 2 of the invention provides a carbon fiber battery pack with a plurality of groups of embedded metal nuts 3, and the integrated forming process of the carbon fiber battery pack with the plurality of groups of embedded metal nuts 3 is an RTM liquid process. The carbon fiber battery package is used for placing a new energy battery, and the metal nut 3 is used for connecting the carbon fiber battery package and metal parts, so that structural and mechanical damages possibly caused by punching of the battery package are avoided. The RTM liquid forming process comprises a mold design and a metal nut embedding scheme. The carbon fiber battery pack with the embedded multiple groups of metal nuts is made of fiber reinforced resin matrix composite materials, and the reinforced fibers comprise carbon fiber fabrics; the resin is modified epoxy resin.

The metal nuts 3 are standard stainless steel flange nuts, are completely embedded into the four side faces 2 of the carbon fiber battery pack, are flush with the surface of the carbon fiber battery pack, and are 12 in number.

The metal nut 3 pre-embedding scheme is as follows: the fiber layering comprises a lower layer of fiber fabric 5, a middle composite material plate 4 and an upper layer of fiber fabric 6. The lower carbon fiber fabric is directly laid on the metal male die 1, and the upper carbon fiber fabric covers the middle composite material plate 4 and is reserved with a threaded hole 8. The middle composite material plate 4 is embedded with the metal nuts 3, the composite material plate 4 is formed by compression molding of carbon fiber prepreg, the thickness of the composite material plate 4 is smaller than that of the nuts, the outer size of the nuts is carved on the composite material plate 4, and a plurality of groups of nuts are embedded into the composite material plate 4 according to design positions.

And (3) closing the female die 7 and the male die 1 to form a closed die cavity, mixing the modified epoxy resin into a curing agent by an injection machine, injecting into the closed die cavity, and curing and molding.

Example 3

The invention relates to a forming die for RTM forming of a pre-embedded metal nut composite material box body, which comprises the following steps:

step 1, nesting a metal nut 3 in an intermediate composite plate 4: carving a cavity on the composite material plate 4 according to the outer size of the nut, and embedding a plurality of groups of metal nuts 3 into the composite material plate 4 according to the designed positions;

step 2, respectively layering a lower layer fiber fabric 5 and an upper layer fiber fabric 6 on the two lower sides of the composite material plate 4;

step 3, directly laying a lower layer of fiber fabric 5 on the male die 1, coating the composite material plate 4 with an upper layer of fiber fabric 6, reserving a nut accommodating hole on the upper layer of fiber fabric 6, and aligning the nut accommodating hole with the metal nut 3;

step 4, placing a female die 7 above the upper-layer fiber fabric 6, aligning a threaded hole 8 with a nut accommodating hole and a metal nut 3, and fixing the threaded hole, the nut accommodating hole and the metal nut 3 through a bolt 9 to form a die set I;

and 5, selecting one set of mold group I and four sets of mold group II which only consists of a female mold 7 and a male mold 1 to assemble the molds, injecting fiber reinforced resin matrix composite material into the closed mold cavity through an injection machine, and preparing the composite material box body 10 with one embedded metal nut panel and four top openings without metal nut panels (side walls or bottom 2 in the drawing) through an RTM (resin transfer molding) process, wherein the structure of the composite material box body is shown in figure 2.

The fiber is glass fiber fabric or/and carbon fiber fabric, and the resin is unsaturated resin, vinyl resin or epoxy resin.

The RTM integral forming process designed by the invention has low cost and small pollution to workshop environment, can meet increasingly strict requirements of environmental protection laws and regulations, and can provide a composite material part with excellent performance.

Example 4

The embodiment of the invention is different from the embodiment 3 in the step 5 of assembling two sets of die sets I and three sets of die sets II which are only composed of a female die 7 and a male die 1, then injecting fiber reinforced resin matrix composite material into a closed die cavity through an injection machine, and preparing the composite material box body with two embedded metal nut panels and three top openings without metal nut panels through an RTM (resin transfer molding) process.

Example 5

The embodiment of the invention is different from the embodiment 3 in the step 5 of assembling three sets of die sets I and two sets of die sets II which are only composed of a female die 7 and a male die 1, then injecting fiber reinforced resin matrix composite material into a closed die cavity through an injection machine, and preparing the composite material box body with three embedded metal nut panels and two top openings without metal nut panels through an RTM (resin transfer molding) process.

Example 6

The embodiment of the invention is different from the embodiment 3 in the step 5 of assembling four sets of die sets I and a set of die set II which is only composed of a female die 7 and a male die 1, then injecting fiber reinforced resin matrix composite material into a closed die cavity through an injection machine, and preparing a composite material box body which is provided with four embedded metal nut panels and a top opening without a metal nut panel through an RTM (resin transfer molding) process.

Example 7

The difference between the embodiment of the invention and the embodiment 3 is that in the step 5, five sets of die sets, namely one set, are selected to be assembled and closed, then the fiber reinforced resin matrix composite material is injected into the closed die cavity through an injection machine, and the composite material box body with the top opening and five embedded metal nut panels is prepared through an RTM (resin transfer molding) process.

The above-described embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.