A composite material bus bottom mold with convenient demoulding and its preparation method

Abstract

The invention relates to a composite passenger car underbody mold for easy demoulding and a preparation method thereof; a floor molding part between front wheels and a floor molding part between rear wheels of a main body mold are designed with movable blocks, a front movable block mold conforming to the floor molding part between the front wheels and a rear movable block mold conforming to the floor molding part between the rear wheels are respectively prepared by using composite materials, and an installation position of a push mechanism is designed, and the cooperation with the push mechanism during demoulding can realize rapid demoulding of the product, the front movable block mold and the rear movable block mold are made of the same material as the main body mold, have the same thermal expansion coefficient, will not be deformed or dislocated during the molding and heating process, and deformation of the obtained underbody plate is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle bottom moulds, and in particular to a composite material passenger vehicle bottom mould which is convenient for demoulding and a preparation method thereof. Background Art

[0002] With the rapid development of the global automotive industry, automobile lightweighting has become a core strategy to improve fuel efficiency, reduce emissions and enhance vehicle performance, and bus chassis design is also undergoing continuous technological innovation. The chassis of traditional buses is mainly made of metal materials such as steel. These materials have high strength, toughness and stability, but they show significant limitations in lightweight, corrosion resistance and fuel efficiency. In recent years, composite materials, as an advanced new material, have been widely used in the automotive manufacturing industry due to their excellent properties such as light weight, high strength and corrosion resistance. Especially in bus chassis design, the application of composite materials has shown great potential. The composite vehicle bottom can not only significantly reduce the weight of the vehicle, but also improve fuel economy and driving stability, while providing better sound insulation and heat insulation, and improving the integration of components. However, as Figure 1 As shown, it is a composite vehicle floor panel, including front door pedal 91, cockpit area 92, front wheel cover 93, front wheel floor 94, front and rear wheel floor 95, rear door pedal 96, rear wheel cover 97, rear wheel floor 98 and rear step 99. The above structure is usually a non-standard multi-faceted irregular shape, including multiple concave and convex vertical surfaces, curved surfaces and inclined surfaces, and folded edges perpendicular to these surfaces are evenly distributed around. Composite products with this structure often face challenges in molding quality control and demoulding. The molds used to replicate vehicle bottom products also face design and manufacturing difficulties. Therefore, the mold structure design, function design and molding method of vehicle bottom products are particularly critical.

[0003] CN106273099A discloses a demoulding structure and demoulding method for a large vacuum infusion mold. The mold adopts metal inserts and ejection and exhaust mechanisms to solve the problem of demoulding products due to complex product appearance and structure and too small draft angle. The ejection and exhaust mechanisms are used to solve the problem of product infusion defects caused by excessive thickness of local layers of the product. The ejection and exhaust mechanisms that do not need to be embedded in the main shell of the mold are used to avoid the problem of cracking of metal embedded parts in the main shell of the composite material mold. However, there are many disadvantages of the inserts designed as above, which are mainly manifested in: 1) The inserts are made of metal, which does not match the thermal expansion coefficient of the composite material main mold, resulting in deformation, dislocation and other problems in the mold during use; 2) Composite materials are sensitive to temperature, and metal inserts may cause local overheating of the composite material, affecting its performance; 3) There are many vertical surfaces at the wheel hubs of the four wheels, and an insert is designed for each vertical surface, resulting in too many vertical surfaces, increasing the complexity and cost of the mold, extending the processing cycle, increasing the difficulty of maintenance, and increasing the risk of deformation of the wheel profile; 4) When encountering a narrow aisle between the wheel hubs of the two wheels, although this insert design method can solve the demolding problem, the machine tool head cannot enter the narrow space to process the positive mold of the bottom of the vehicle, and faces manufacturing difficulties.

[0004] Therefore, in view of the above problems, the present invention urgently needs to provide a composite material bus bottom mold that is easy to demould and a preparation method thereof. Summary of the invention

[0005] The purpose of the present invention is to provide a composite bus underbody mold that is easy to demold and a preparation method thereof. The method for preparing a composite bus underbody mold that is easy to demold can solve the technical problems in the prior art that the composite bus underbody structure is a non-standard multi-faceted irregular shape, the existing mold is difficult to demold, and the product surface is easily damaged.

[0006] The present invention provides a method for preparing a composite bus underbody mold that is easy to demould, comprising the following steps:

[0007] According to the required shape of the vehicle floor, a main mold for preparing the vehicle floor is prepared by using composite materials. The floor forming part between the front wheels and the floor forming part between the rear wheels of the main mold are designed with movable blocks. The floor forming part between the front wheels is reserved with a front limit groove, and the floor forming part between the rear wheels is reserved with a rear limit groove. The bottoms of the front limit groove and the rear limit groove are both reserved with embedded grooves for installing a push mechanism, and the bottoms of each embedded groove are provided with a through hole for a push rod of the push mechanism to pass through.

[0008] A front movable block mold conforming to the molding part of the floor between the front wheels and a rear movable block mold conforming to the molding part of the floor between the rear wheels are respectively prepared by using composite materials;

[0009] A push mechanism is installed in each embedded groove, and a push rod of the push mechanism is fixed to the main mold through a nut through a through hole, and the front movable block mold is fixed to the front limit groove, and the rear movable block mold is fixed to the rear limit groove. After assembly, a composite bus bottom mold that is easy to demould is obtained.

[0010] Preferably, the pushing mechanism includes a flange that is tightly fitted into the embedded groove, and the lower end surface of the flange is provided with a pushing rod that passes through the through hole, and the bottom of the pushing rod is provided with an exhaust hole, which passes through the flange upward, and the outer wall of the pushing rod is provided with an external thread, and the nut is screwed and fixed to the pushing rod through the external thread.

[0011] Preferably, a sealing groove is provided on the lower plate surface of the flange along the periphery of the push rod, and a sealing gasket is tightly embedded in the sealing groove.

[0012] Preferably, the front live block mold comprises a first front live block unit, a second front live block unit and a third front live block unit which are sequentially spliced. After the front live block mold is installed in the front limit groove, the gap between the first front live block unit and the second front live block unit and the splicing seam between the second front live block unit and the third front live block unit are filled with fillers;

[0013] The joint surfaces of the first front movable block unit, the second front movable block unit and the third front movable block unit are all provided with a draft angle;

[0014] The rear movable block mold comprises a first rear movable block unit, a second rear movable block unit and a third rear movable block unit which are sequentially spliced. After the rear movable block mold is installed in the rear limit groove, the gap between the first rear movable block unit and the second rear movable block unit and the splicing seam between the second rear movable block unit and the third rear movable block unit are filled with fillers;

[0015] The joint surfaces of the first rear movable block unit, the second rear movable block unit and the third rear movable block unit are all provided with draft angles.

[0016] Preferably, the draft angle is 4°-6°.

[0017] Preferably, the first front movable block unit, the second front movable block unit and the third front movable block unit are provided with front hanging holes on opposite sides;

[0018] Rear hoisting holes are arranged on opposite sides of the first rear movable block unit, the second rear movable block unit and the third rear movable block unit.

[0019] Preferably, four embedded grooves are provided on the main mold, namely the first embedded groove, the second embedded groove, the third embedded groove and the fourth embedded groove. The first embedded groove is located below the first front live block unit, the second embedded groove is located below the third front live block unit, the third embedded groove is located below the first rear live block unit, and the fourth embedded groove is located below the third rear live block unit.

[0020] Preferably, heating wires are provided in the first front live block unit, the second front live block unit, the third front live block unit, the first rear live block unit, the second rear live block unit and the third rear live block unit, and the power line of each heating wire is led out from the exhaust hole of the corresponding or adjacent pushing mechanism.

[0021] Preferably, the preparation method of the first front live block unit, the second front live block unit and the third front live block unit comprises:

[0022] Prepare a male mold A, which includes two mating bottom plates A, each bottom plate A has an outer end surface provided with a side plate A extending upward, the bottom plate A and the two side plates A are surrounded by a molding groove A, three plug-in grooves A are provided along the length direction of the bottom plate A, and the inner wall of the corresponding side plate A is provided with a side groove A that penetrates the plug-in groove A;

[0023] Insert the partition plate A into each insertion slot A, and insert both side ends of each partition plate A into the corresponding side slot A to separate the forming slot A into three unit slots A;

[0024] In each unit slot A, hand lay up the fiberglass reinforced plastic according to the shape. After solidification, a heating wire is laid on the fiberglass reinforced plastic and fixed. Then, fiberglass cloth, foam and fiberglass cloth are laid. The vacuum infusion process is used for molding. The male mold A is removed to obtain the first front block unit, the second front block unit and the third front block unit.

[0025] The preparation method of the first rear movable block unit, the second rear movable block unit and the third rear movable block unit comprises:

[0026] Prepare a male mold B, which includes two mating bottom plates B, each bottom plate B has a side plate B extending upward on its outer end surface, and the bottom plate B and the two side plates B are surrounded by a molding groove B;

[0027] Three plug-in slots B are provided along the length direction of the bottom plate B, and the inner wall of the corresponding side plate B is provided with a side slot B which is connected with the plug-in slots B;

[0028] Insert the partition plates B into each insertion slot B, and insert both side ends of each partition plate B into the corresponding side slots B, so as to separate the forming slot B into three unit slots B;

[0029] FRP is laid up by hand in each unit slot B. After solidification, heating wires are laid on the FRP and fixed. Glass fiber cloth, foam and glass fiber cloth are laid. Vacuum infusion process is used for molding. The positive mold B is removed to obtain the first rear live block unit, the second rear live block unit and the third rear live block unit.

[0030] The present invention also provides a composite material bus bottom mold that is easy to demould, obtained based on any of the above-mentioned methods for preparing a composite material bus bottom mold that is easy to demould.

[0031] The composite material bus underbody mold and its molding method provided by the present invention have the following improvements compared with the prior art:

[0032] 1. The present invention provides a method for preparing a composite bus underbody mold that is easy to demold. The floor molding parts between the front wheels and the floor molding parts between the rear wheels of the main mold are designed with movable blocks. Composite materials are used to prepare a front movable block mold that follows the molding part of the floor between the front wheels and a rear movable block mold that follows the molding part of the floor between the rear wheels, and the installation position of the push mechanism is designed. During demolding, the front movable block mold, the rear movable block mold and the push mechanism cooperate to quickly demold the molded product. The front movable block mold and the rear movable block mold are made of the same material as the main mold and have the same thermal expansion coefficient. They will not be deformed or dislocated during the molding and heating process, thereby preventing the obtained underbody from being deformed.

[0033] 2. The present invention has three functions through the design of the pushing mechanism. First, it can apply an upward jack force to the pushing mechanism to realize the ejection of the front block mold and the rear block mold; second, it can output the gas generated when the front block mold and the rear block mold are connected to the main mold of the bottom of the vehicle; third, heating wires are arranged inside the front block mold and the rear block mold, and the power cord of the heating wire can be led out from the exhaust hole. The structural design is simple, and can complete the functions of exhaust, power cord lead-in and pushing, which is convenient for installation and disassembly.

[0034] 3. The method for preparing a composite bus underbody mold provided by the present invention adopts a split design of a movable block mold, wherein the front movable block mold includes a first front movable block unit, a second front movable block unit and a third front movable block unit which are connected in sequence; the rear movable block mold includes a first rear movable block unit, a second rear movable block unit and a third rear movable block unit which are connected in sequence, that is, the front movable block mold and the rear movable block mold are divided into three parts, which is convenient for processing and subsequent demolding.

[0035] 4. The method for preparing a composite material bus underbody mold provided by the present invention comprises four installation grooves on the main mold, namely a first installation groove, a second installation groove, a third installation groove and a fourth installation groove, the first installation groove is located below the first front live block unit, the second installation groove is located below the third front live block unit, the third installation groove is located below the first rear live block unit, and the fourth installation groove is located below the third rear live block unit. During demolding, the first front live block unit and the third front live block unit are demolded together with the product, and the first rear live block unit and the third rear live block unit are demolded together. A plurality of pushing mechanisms can be installed to share the stress points of the front live block mold and the rear live block mold to avoid stress concentration, affect the shape of the finished product, and improve the quality of the obtained product. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 It is a structural schematic diagram (stereoscopic diagram) of the vehicle bottom plate described in the background technology;

[0038] Figure 2 It is a structural schematic diagram of the main mold described in the present invention (stereoscopic diagram, without the front live block mold and the rear live block mold);

[0039] Figure 3 It is a structural schematic diagram (stereoscopic diagram) of the main mold of the present invention;

[0040] Figure 4 It is a structural diagram (partial cross-sectional view) of the installation of the ejector rod and the main mold of the present invention;

[0041] Figure 5 It is a structural schematic diagram (stereoscopic diagram) of the front live block mold of the present invention;

[0042] Figure 6 It is a structural schematic diagram (stereoscopic diagram) of the rear movable block mold described in the present invention;

[0043] Figure 7 It is a structural schematic diagram (stereoscopic diagram) of the male mold A described in the present invention;

[0044] Figure 8 It is a structural schematic diagram (stereoscopic diagram) of the male mold B described in the present invention;

[0045] Description of reference numerals:

[0046] 1. Main body mold; 2. Front movable block mold; 21. First front movable block unit; 22. Second front movable block unit; 23. Third front movable block unit; 3. Rear movable block mold; 31. First rear movable block unit; 32. Second rear movable block unit; 33. Third rear movable block unit; 4. Front limit groove; 5. Perforation; 6. Flange; 7. Push rod; 8. Air hole; 9. Nut; 10. Rear limit groove; 12. Male mold A; 121. Bottom plate A; 122. Side plate A; 123. Partition plate A; 13. Male mold B; 131. Bottom plate B; 132. Side plate B; 133. Partition plate B. DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0049] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] like Figure 2 , Figure 3 As shown, the present embodiment provides a method for preparing a composite bus underbody mold that is easy to demould, comprising the following steps:

[0051] 101) According to the required shape of the vehicle floor, a main body mold 1 for preparing the vehicle floor is prepared by using composite materials. The front wheel inter-floor forming part and the rear wheel inter-floor forming part of the main body mold 1 are designed with movable blocks. The front wheel inter-floor forming part is reserved with a front limiting groove 4, and the rear wheel inter-floor forming part is reserved with a rear limiting groove 10. The bottoms of the front limiting groove 4 and the rear limiting groove 10 are both reserved with embedded grooves for installing a push mechanism, and the bottoms of each embedded groove are provided with a through hole 5 for a push rod of the push mechanism to pass through;

[0052] 102) A front movable block mold 2 conforming to the molding part of the floor between the front wheels and a rear movable block mold 3 conforming to the molding part of the floor between the rear wheels are respectively prepared using composite materials;

[0053] 103) A push mechanism is installed in each embedded groove, and a push rod of the push mechanism is fixed to the main mold 1 through a through-hole 5 and a nut 9, and the front movable block mold 2 is fixed to the front limit groove 4, and the rear movable block mold 3 is fixed to the rear limit groove 10. After assembly, a composite bus bottom mold that is easy to demould is obtained.

[0054] The present invention provides a method for preparing a composite bus underbody mold that is easy to demold. The floor molding parts between the front wheels and the floor molding parts between the rear wheels of the main mold 1 are designed with movable blocks. A front movable block mold 2 that follows the molding part of the floor between the front wheels and a rear movable block mold 3 that follows the molding part of the floor between the rear wheels are prepared using composite materials. The installation position of a push mechanism is designed. During demolding, the front movable block mold 2, the rear movable block mold 3 cooperate with the push mechanism to quickly demold the molded product. The front movable block mold 2 and the rear movable block mold 3 are made of the same material as the main mold 1 and have the same thermal expansion coefficient. They will not be deformed or misaligned during the molding and heating process, thereby preventing the obtained underbody from being deformed.

[0055] The design of the front limit groove 4 and the rear limit groove 10 of the present invention facilitates the precise matching of the front movable block mold 2 and the rear movable block mold 3. The bottoms of the front limit groove 4 and the rear limit groove 10 are lower than the upper end surfaces of the front wheel cover molding parts and the rear wheel cover molding parts adjacent to the main mold 1. The front movable block mold 2 and the rear movable block mold 3 can be embedded to a certain depth to avoid shaking of the front movable block mold 2 and the rear movable block mold 3, thereby ensuring the stability of the installation.

[0056] The filler of the present invention is filled with putty. The joint between the front movable block mold 2 and the main mold is filled with putty, scraped flat, and covered with Teflon high-temperature tape; the joint between the rear movable block mold 3 and the main mold 1 is filled with putty, scraped flat, and covered with Teflon high-temperature tape.

[0057] like Figure 4 As shown, the pushing mechanism provided in this embodiment includes a flange 6 which is tightly fitted into the embedded groove, the lower end surface of the flange 6 is provided with a pushing rod 7 which passes through the through hole 5, the bottom of the pushing rod 7 is provided with an exhaust hole, the exhaust hole passes through the flange 6 upward, the outer wall of the pushing rod 7 is provided with an external thread, and the nut 9 is screwed and fixed to the pushing rod 7 through the external thread; heating wires are arranged inside the front live block mold 2 and the rear live block mold 3; it can ensure that the front live block mold and the rear live block mold have the heating function like the main mold, so as to ensure the overall molding effect of the vehicle floor.

[0058] The present invention designs a pushing mechanism, and the pushing mechanism has three functions. First, an upward jack force can be applied to the pushing mechanism to realize the ejection of the front block mold 2 and the rear block mold 3; second, the gas generated when the front block mold 2 and the rear block mold 3 are connected to the main mold 1 of the bottom of the vehicle can be output; third, heating wires are arranged inside the front block mold 2 and the rear block mold 3, and the power cord of the heating wire can be led out from the exhaust hole. The structural design is simple, and the functions of exhaust, power cord lead-in and pushing can be completed, which is convenient for installation and disassembly.

[0059] like Figure 4 As shown, a sealing groove is provided on the lower plate surface of the flange 6 of this embodiment along the periphery of the push rod 7, and a sealing gasket is tightly embedded in the sealing groove; the sealing gasket is made of rubber and fits tightly to the main mold 1, thereby preventing leakage of gas, resin glue, etc., ensuring the sealing of the system and preventing leakage of the medium.

[0060] like Figure 5 As shown, the front live block mold 2 of this embodiment includes a first front live block unit 21, a second front live block unit 22 and a third front live block unit 23 which are spliced ​​in sequence. After the front live block mold 2 is installed in the front limit groove 4, the gap between the first front live block unit 21 and the second front live block unit 22 and the splicing seam between the second front live block unit 22 and the third front live block unit 23 are filled with fillers; the splicing surfaces of the first front live block unit 21, the second front live block unit 22 and the third front live block unit 23 are all provided with a draft angle; due to design requirements, the outer wall of the front live block mold 2 needs to be processed into a vertical surface, The vertical surface of 800mm is not easy to demold, so the front block mold 2 is designed to be split, and the joint surfaces of the first front block unit 21, the second front block unit 22 and the third front block unit 23 are all provided with draft angles to facilitate demolding. In addition, the overall weight of the front block mold 2 is about 400 kg, which is inconvenient to hoist as a whole. The split design makes hoisting convenient. During ejection, due to the split setting of the front block mold 2, the weight of the unit component is reduced, and the ejection force required is reduced compared to the integral component, thereby avoiding adverse effects on the overall shape of the product due to excessive ejection force.

[0061] like Figure 6As shown, the rear movable block mold 3 of this embodiment includes a first rear movable block unit 31, a second rear movable block unit 32 and a third rear movable block unit 33 which are spliced ​​in sequence. After the rear movable block mold 3 is installed in the rear limit groove 10, the gap between the first rear movable block unit 31 and the second rear movable block unit 32 and the splicing seam between the second rear movable block unit 32 and the third rear movable block unit 33 are filled with fillers; the splicing surfaces of the first rear movable block unit 31, the second rear movable block unit 32 and the third rear movable block unit 33 are all provided with a draft angle; the two sides of the rear movable block mold 3 are right-angled surfaces, which are not easy to demold during demolding. Therefore, the front movable block mold 2 is split-designed, and the splicing surfaces of the first rear movable block unit 31, the second rear movable block unit 32 and the third rear movable block unit 23 are all provided with a draft angle to facilitate demolding. In addition, the overall weight of the rear movable block mold 3 is about 400 kilograms, which is inconvenient to hoist as a whole. The split design is convenient for hoisting. Furthermore, during ejection, since the rear live block mold 3 is separately arranged, the weight of the single component is reduced, and the ejection force required is reduced compared to the integral component, thereby avoiding adverse effects on the overall shape of the product due to excessive ejection force.

[0062] In some embodiments, the draft angle is 4°-6°, and the setting of the draft angle makes demolding easier.

[0063] In some embodiments, the first front movable block unit 21, the second front movable block unit 22 and the third front movable block unit 23 are provided with front lifting holes on both sides; the first rear movable block unit 31, the second rear movable block unit 32 and the third rear movable block unit 33 are provided with rear lifting holes on both sides. The above design facilitates grabbing with a lifting hook and facilitates lifting.

[0064] In some embodiments, four embedded grooves are provided on the main mold 1, namely the first embedded groove, the second embedded groove, the third embedded groove and the fourth embedded groove. The first embedded groove is located below the first front live block unit 21, the second embedded groove is located below the third front live block unit 23, the third embedded groove is located below the first rear live block unit 31, and the fourth embedded groove is located below the third rear live block unit 33. Multiple pushing mechanisms can be installed to share the force points of the front live block mold 2 and the rear live block mold 3 to avoid stress concentration, affect the shape of the finished product, and improve the quality of the obtained product.

[0065] like Figure 7 As shown, the preparation method of the first front live block unit 21, the second front live block unit 22 and the third front live block unit 23 of this embodiment includes:

[0066] 201) preparing a male mold A12, the male mold A12 comprising two mating bottom plates A121, the outer end surface of each bottom plate A121 is provided with a side plate A122 extending upward, and the bottom plate A121 and the two side plates A122 are surrounded by a molding groove A;

[0067] 202) Three plug-in slots A are provided along the length direction of the bottom plate A121, and the inner wall of the corresponding side plate A122 is provided with a side slot A which penetrates the plug-in slots A;

[0068] 203) Insert the partition plates A123 into each insertion slot A, and insert both side ends of each partition plate A123 into the corresponding side slot A, so as to separate the forming slot A into three unit slots A;

[0069] 204) FRP is hand-laid in each unit slot A. After solidification, heating wires are laid on the FRP and fixed. Glass fiber cloth, foam and glass fiber cloth are laid. Vacuum infusion process is used for molding. The positive mold A is removed to obtain the first front block unit 21, the second front block unit 22 and the third front block unit 23.

[0070] The inner wall of the male mold A12 needs to be processed to obtain the required shape of the floor molding part between the front wheels. The bottom width of the male mold A12 is only 450-500mm. If the integral male mold A12 is used, the processing head of the CNC machine tool cannot be inserted to perform surface processing, and it can only be processed manually, with low production efficiency and poor accuracy. The design of the male mold A12 of the present invention is that the male mold A12 includes two matching bottom plates A121, and the outer end surface of each bottom plate A121 is provided with a side plate A122 extending upward. The bottom plate A121 and the two side plates A122 are surrounded by a molding groove A. The split design is conducive to using the processing head of the CNC machine tool to process it into the required shape, which is convenient for processing and improves work efficiency. At the same time, the split design is also conducive to later demolding. In addition, the design of the partition plate A123 can realize the simultaneous molding of the first front live block unit 21, the second front live block unit 22 and the third front live block unit 23, and can be demolded smoothly.

[0071] like Figure 8 As shown, the preparation method of the first rear movable block unit 31, the second rear movable block unit 32 and the third rear movable block unit 33 of this embodiment includes:

[0072] 301) Prepare a male mold B13, the male mold B13 comprises two mating bottom plates B131, the outer end surface of each bottom plate B131 is provided with a side plate B132 extending upward, and the bottom plate B131 and the two side plates B132 are surrounded by a molding groove B;

[0073] 302) Three plug-in slots B are provided along the length direction of the bottom plate B131, and the inner wall of the corresponding side plate B132 is provided with a side slot B which is connected with the plug-in slots B;

[0074] 303) Insert the partition plates B133 into each insertion slot B, and insert both side ends of each partition plate B133 into the corresponding side slots B to separate the molding slot B into three unit slots B;

[0075] 304) FRP is laid up by hand in each unit slot B. After solidification, heating wire is laid on the FRP and fixed. Glass fiber cloth, foam and glass fiber cloth are laid. Vacuum infusion process is adopted to form the FRP. The positive mold B is removed to obtain the first rear live block unit 31, the second rear live block unit 32 and the third rear live block unit 33.

[0076] The inner wall of the male mold B13 needs to be processed to obtain the required shape of the rear wheel inter-floor forming part. The bottom width of the male mold B13 is only 450-500mm. If the integral male mold B13 is used, the processing head of the CNC machine tool cannot be inserted to perform profile processing, and it can only be processed manually, with low production efficiency and poor accuracy. The design of the male mold B13 of the present invention is that the male mold B13 includes two matching bottom plates B131, and the outer end surface of each bottom plate B131 is provided with a side plate B132 extending upward. The bottom plate B131 and the two side plates B132 are surrounded by a forming groove A. The split design is conducive to using the processing head of the CNC machine tool to process into the required shape, which is convenient for processing and improves work efficiency. At the same time, the split design is also conducive to later demolding. In addition, the design of the partition plate B133 can realize the simultaneous molding of the first rear movable block unit 31, the second rear movable block unit 32 and the third rear movable block unit 33, and can be demolded smoothly.

[0077] The front movable block mold 2 and the rear movable block mold 3 of the present invention are internally added with foam, so as to reduce the overall weight while ensuring the thickness.

[0078] In the preparation process of the main mold 1, glass fiber cloth is laid, and vacuum infusion process is adopted to form. After curing, heating wire is laid on the glass fiber reinforced plastic and the heating wire is fixed, and then glass fiber cloth is laid, and vacuum infusion process is adopted to form. Therefore, the main mold 1, the front movable block mold 2 and the rear movable block mold 3 all have heating function.

[0079] Installation process of composite bus bottom mold for easy demoulding:

[0080] 1) Fix the push mechanism in the first embedded groove, the second embedded groove, the third embedded groove and the fourth embedded groove respectively;

[0081] 2) Lift the prepared first front movable block unit 21, second front movable block unit 22 and third front movable block unit 23 respectively, and place the first front movable block unit 21, second front movable block unit 22 and third front movable block unit 23 into the front limit groove 4. Before they are completely placed, the power cords of the first front movable block unit 21, second front movable block unit 22 and third front movable block unit 23 are led out from the corresponding pushing mechanism, and the positions are adjusted. The joints between the first front movable block unit 21, second front movable block unit 22 and third front movable block unit 23 are filled with putty, scraped flat and covered with Teflon high-temperature tape. The joints between the first front movable block unit 21, second front movable block unit 22 and third front movable block unit 23 and the front limit groove 4 are filled with putty, scraped flat and covered with Teflon high-temperature tape.

[0082] 3) Lift the prepared first rear movable block unit 31, second rear movable block unit 32 and third rear movable block unit 33 respectively, and place the first rear movable block unit 31, second rear movable block unit 32 and third rear movable block unit 33 in the rear limit groove 10. Before they are completely placed, the power lines of the first rear movable block unit 31, second rear movable block unit 32 and third rear movable block unit 33 are led out from the corresponding pushing mechanism, and the positions are adjusted. The joints between the first rear movable block unit 31, second rear movable block unit 32 and third rear movable block unit 33 are filled with putty, scraped flat, and covered with Teflon high-temperature tape. The joints between the first rear movable block unit 31, second rear movable block unit 32 and third rear movable block unit 33 and the rear limit groove 10 are filled with putty, scraped flat, and covered with Teflon high-temperature tape.

[0083] Car floor preparation process:

[0084] Lay biaxial / quadruple-axial carbon fiber cloth / glass fiber cloth, PVC foam, embedded parts and other main materials on the assembled vehicle bottom mold, and then lay auxiliary materials for infusion, connect the exhaust device and the push rod arranged on the surface of the auxiliary materials to the vacuum pump respectively, and perform vacuum infusion after reaching the specified infusion pressure and maintaining it stably. After the infusion is completed, connect the power cord of the heating wire to the power supply, heat and cure, and obtain the vehicle bottom plate;

[0085] Demolding process of vehicle floor:

[0086] Disconnect the power supply, configure a bottom bracket at the lower end of the push rod, support the hydraulic jack at the bottom of the bottom bracket, the hydraulic jack applies a vertical upward force to the bottom bracket, and at the same time use a lifting mechanism to lift the vehicle bottom plate to complete the demoulding of the vehicle bottom plate.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a composite passenger car bottom mold that is easy to demould, characterized in that: The steps include: A main body mold (1) for preparing the vehicle floor panel is prepared using composite materials according to the required shape of the vehicle floor panel. The main body mold (1) is designed with movable blocks at the front wheel inter-floor molding part and the rear wheel inter-floor molding part. The front wheel inter-floor molding part reserves a front limit groove (4), and the rear wheel inter-floor molding part reserves a rear limit groove (10). The bottoms of the front limit groove (4) and the rear limit groove (10) are both reserved with embedded grooves for installing a push mechanism. The bottom of each embedded groove is provided with a through hole (5) for a push rod of the push mechanism to pass through. A front movable block mold (2) conforming to the molding part of the floor between the front wheels and a rear movable block mold (3) conforming to the molding part of the floor between the rear wheels are respectively prepared using composite materials; A push mechanism is installed in each embedded groove, a push rod of the push mechanism passes through a through hole (5) and is fixed to the main mold (1) through a nut (9), the front movable block mold (2) is fixed to the front limit groove (4), and the rear movable block mold (3) is fixed to the rear limit groove (10), and after assembly, a composite material bus bottom mold that is easy to demould is obtained; The push mechanism comprises a flange (6) which is tightly fitted into the inner groove, a push rod (7) which is passed through the through hole (5) is provided on the lower end surface of the flange (6), an air extraction hole is provided at the bottom of the push rod (7), the air extraction hole passes through the flange (6) upward, an external thread is provided on the outer wall of the push rod (7), and a nut (9) is screwed and fixed to the push rod (7) through the external thread; The front movable block mold (2) comprises a first front movable block unit (21), a second front movable block unit (22) and a third front movable block unit (23) which are sequentially spliced ​​together. After the front movable block mold (2) is installed in the front limit groove (4), the gap between the first front movable block unit (21) and the second front movable block unit (22) and the splicing seam between the second front movable block unit (22) and the third front movable block unit (23) are filled with fillers; The joint surfaces of the first front movable block unit (21), the second front movable block unit (22) and the third front movable block unit (23) are all provided with a draft angle; The rear movable block mold (3) comprises a first rear movable block unit (31), a second rear movable block unit (32) and a third rear movable block unit (33) which are sequentially spliced ​​together. After the rear movable block mold (3) is installed in the rear limit groove (10), the gap between the first rear movable block unit (31) and the second rear movable block unit (32) and the splicing seam between the second rear movable block unit (32) and the third rear movable block unit (33) are filled with fillers; The joint surfaces of the first rear movable block unit (31), the second rear movable block unit (32) and the third rear movable block unit (33) are all provided with a draft angle; The main body mold (1) is provided with four embedded grooves, namely a first embedded groove, a second embedded groove, a third embedded groove and a fourth embedded groove, the first embedded groove being located below the first front movable block unit (21), the second embedded groove being located below the third front movable block unit (23), the third embedded groove being located below the first rear movable block unit (31), and the fourth embedded groove being located below the third rear movable block unit (33).

2. The method for preparing a composite passenger car bottom mold with convenient demoulding according to claim 1, characterized in that: A sealing groove is provided on the lower plate surface of the flange (6) along the periphery of the push rod (7), and a sealing gasket is tightly embedded in the sealing groove.

3. The method for preparing a composite passenger car bottom mold with convenient demoulding according to claim 1, characterized in that: The draft angle is 4°-6°.

4. The method for preparing a composite passenger car bottom mold with convenient demoulding according to claim 1, characterized in that: Front hanging holes are provided on opposite sides of the first front movable block unit (21), the second front movable block unit (22) and the third front movable block unit (23); Rear lifting holes are provided on opposite sides of the first rear movable block unit (31), the second rear movable block unit (32) and the third rear movable block unit (33).

5. The method for preparing a composite passenger car bottom mold with convenient demoulding according to claim 1, characterized in that: The first front movable block unit (21), the second front movable block unit (22), the third front movable block unit (23), the first rear movable block unit (31), the second rear movable block unit (32) and the third rear movable block unit (33) are all provided with heating wires, and the power line of each heating wire is led out from the exhaust hole of the corresponding or adjacent pushing mechanism.

6. The method for preparing a composite passenger car bottom mold with convenient demoulding according to claim 5, characterized in that: The preparation method of the first front live block unit (21), the second front live block unit (22) and the third front live block unit (23) comprises: A male mold A (12) is prepared, wherein the male mold A (12) comprises two mating bottom plates A (121), the outer end surface of each bottom plate A (121) is provided with a side plate A (122) extending upward, the bottom plate A (121) and the two side plates A (122) are surrounded by a molding groove A, three plug-in grooves A are provided at intervals along the length direction of the bottom plate A (121), and the inner wall of the corresponding side plate A (122) is provided with a side groove A that penetrates the plug-in groove A; Insert the partition plates A (123) into each insertion groove A, and insert both side ends of each partition plate A (123) into the corresponding side groove A to divide the forming groove A into three unit grooves A; Hand lay up the glass fiber reinforced plastic in each unit groove A, and after solidification, lay out a heating wire on the glass fiber reinforced plastic and fix the heating wire, then lay out glass fiber cloth, foam and glass fiber cloth, adopt vacuum infusion process to form, remove the positive mold A, and obtain a first front movable block unit (21), a second front movable block unit (22) and a third front movable block unit (23); The preparation method of the first rear movable block unit (31), the second rear movable block unit (32) and the third rear movable block unit (33) comprises: Prepare a male mold B (13), the male mold B (13) comprising two mating bottom plates B (131), the outer end surface of each bottom plate B (131) being provided with a side plate B (132) extending upward, and the bottom plate B (131) and the two side plates B (132) being provided with a molding groove B; Three plug-in slots B are provided at intervals along the length direction of the bottom plate B (131), and the inner wall of the corresponding side plate B (132) is provided with a side slot B that penetrates the plug-in slots B; Inserting a partition plate B (133) into each insertion slot B, and inserting both side ends of each partition plate B (133) into the corresponding side slot B, so as to divide the forming slot B into three unit slots B; The glass fiber reinforced plastic is hand-laid in each unit groove B. After solidification, a heating wire is laid on the glass fiber reinforced plastic and fixed. Then, glass fiber cloth, foam and glass fiber cloth are laid. The vacuum infusion process is used to form the glass fiber reinforced plastic. The male mold B is removed to obtain a first rear movable block unit (31), a second rear movable block unit (32) and a third rear movable block unit (33).

7. A composite material bus underbody mould that is easy to demould obtained based on the method for preparing a composite material bus underbody mould that is easy to demould according to any one of claims 1 to 6.

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