CN117359962A - Forming device and forming method of connecting ring - Google Patents

Abstract

The invention relates to a molding device and a molding method, wherein the molding device comprises a core mold, a plurality of circumferential stop blocks and a plurality of pushing parts; wherein the mandrel comprises a molding surface for disposing a material to be cured; the plurality of circumferential stops being movably disposed around the mandrel; the plurality of pushing members are used for pushing the plurality of circumferential stoppers to move in a direction approaching the molding surface. According to the forming device of the embodiment of the invention, through the arrangement of the plurality of axial stop blocks and the pushing component, the annular uniform pressurization of the core mold can be effectively realized, and the internal quality of a manufactured product is improved.

Description

Forming device and forming method of connecting ring

Technical Field

The present invention relates to molding devices, and more particularly, to a molding device for a connecting ring.

Background

The connecting ring is an important part for connecting the antenna housing of the aircraft, with the rapid development of the aerospace technology, the speed of the aircraft is increased increasingly, and urgent demands of light weight, high temperature resistance, high bearing capacity and low expansion are put forward for the connecting ring. At present, the connecting ring is generally made of low-expansion alloy steel, and the thermal expansion coefficient of the connecting ring is relatively low, but the connecting ring is large in material specific gravity, long in processing period and high in manufacturing cost. The composite material has the characteristics of high specific strength, high specific rigidity, designability and the like, and the connecting ring is prepared by using the composite material, so that the weight reduction of the structure can be effectively realized, the production period is shortened, and the manufacturing cost is reduced.

However, the traditional epoxy resin-based composite material has lower temperature resistance level, and fails in a high-temperature use environment, so that the use requirement of the connecting ring cannot be met. The polyimide composite material is one of the resin-based composite materials for the structure with the highest temperature resistance level at present, the long-term use temperature range is 200-500 ℃, the polyimide composite material can be used as a bearing structural member in a high-temperature service environment, and the adoption of the high-temperature resistant polyimide for preparing the connecting ring is an effective thought for realizing the weight reduction of the structure, improving the temperature resistance level of the connecting ring and ensuring the high-temperature bearing strength.

The traditional composite material ring structure is molded by RTM molding or winding molding, but the high-temperature resistant polyimide resin has high crosslinking density, and the partially imidized resin oligomer has high segment rigidity, is solid at room temperature, has high softening point temperature, and has high difficulty in RTM molding and high equipment requirement. On the other hand, polyimide resin has larger viscosity at high temperature, poor fluidity, complex solvent volatilization, imidization and crosslinking reactions during the curing process, the problem of difficult control of the gel content and poor internal quality stability of products due to winding molding is solved, and the molded products have low surface quality, poor dimensional accuracy and complex post-processing treatment.

Disclosure of Invention

To overcome at least one of the above-mentioned drawbacks of the prior art, in one aspect, an embodiment of the present invention provides a molding apparatus, including:

a core die comprising a molding surface for providing a material to be solidified;

a plurality of circumferential stops movably disposed around the mandrel; and

and a plurality of pushing members for pushing the plurality of circumferential stoppers to move in a direction approaching the molding surface.

According to an embodiment of the invention, the circumferential block comprises a first side face and a second side face which are arranged opposite to each other, the circumferential block pressing the molding surface through the first side face, and receiving the pressure from the pushing member through the second side face.

According to an embodiment of the invention, the pushing member comprises a third side and a fourth side arranged opposite each other, the third side being intended to act on the second side; the third side face is an inclined face, and the shape of the second side face is matched with that of the third side face.

According to an embodiment of the invention, the pushing member is a wedge; and/or the number of the groups of groups,

the molding device comprises a shell and a cover body, wherein the shell is provided with a cavity, and the core mold, the plurality of circumferential stop blocks and the plurality of pushing components are all arranged in the cavity.

According to one embodiment of the invention, a positioning component is arranged on the shell, and the circumferential stop block is arranged on the positioning component and can be close to or far away from the forming surface along a specific route under the action of the positioning component.

According to an embodiment of the present invention, a boss is provided on the housing, a guide groove is provided on the pushing member, or a guide groove is provided on the housing, a boss is provided on the pushing member; the guide groove is sleeved on the boss, and the pushing component can enter or leave the shell along a specific route under the action of the boss and the guide groove.

According to an embodiment of the present invention, a plurality of through holes are provided in the case, and projections of the through holes in the axial direction of the core mold are located within a region of projections of the pushing member in the axial direction of the core mold.

According to an embodiment of the present invention, the plurality of pushing members press the core mold through the plurality of circumferential stoppers, a first gap is formed between two adjacent circumferential stoppers, a second gap is formed between two adjacent pushing members, and the first gap communicates with the second gap.

According to an embodiment of the present invention, the molding apparatus further includes a stripper ring for stripping the cured product from the core mold, the stripper ring being disposed outside the core mold.

According to an embodiment of the present invention, the pushing member and the circumferential stopper each include an arc-shaped body, and a center of the arc-shaped body of the pushing member and a center of the arc-shaped body of the circumferential stopper are located on the same straight line.

In another aspect, an embodiment of the present invention provides a molding method, including performing compression molding and curing molding using the molding apparatus, including the steps of:

paving a material to be solidified on the molding surface of the core mold; and

the molding surface is pressurized by the pushing components and the circumferential stoppers so as to cure and mold the material to be cured.

According to the forming device of the embodiment of the invention, through the arrangement of the plurality of axial stop blocks and the pushing component, the annular uniform pressurization of the core mold can be effectively realized, and the internal quality of a manufactured product is improved.

In the invention, the technical schemes can be mutually combined to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention. Wherein:

fig. 1 is a sectional view of a molding apparatus according to an embodiment of the present invention taken along the axial direction of a core mold;

FIG. 2 is a top view of the molding apparatus of FIG. 1 without a cover;

FIG. 3 is a schematic view of a connecting ring according to an embodiment of the present invention;

FIG. 4 is a CT photograph of a connecting ring made in accordance with an embodiment of the present invention.

The reference numerals are explained as follows:

10. a core mold; 11. a molding surface; 12. a stripper ring; 20. a circumferential stop; 21. a positioning member; 30. a pushing member; 40. a housing; 41. a bottom; 411. a through hole; 42. a side portion; 421. a boss; 50. a cover body; 60. a gap; 100. and a connecting ring.

Detailed Description

The following detailed description of preferred embodiments of the invention, which form a part hereof, and together with the description of the invention serve to explain the principles of the invention, are not intended to limit the scope of the invention.

An embodiment of the present invention provides a molding apparatus, which can be used to prepare the connection ring 100, and in particular, to prepare the connection ring 100 by using a polyimide composite material as a raw material.

Referring to fig. 1 and 2, a molding apparatus according to an embodiment of the present invention includes:

a core mold 10 including a molding surface 11 for setting a material to be solidified;

a plurality of circumferential stoppers 20 movably disposed around the core mold 10; and

a plurality of pushing members 30 for pushing the plurality of circumferential stoppers 20 to move in a direction approaching the molding surface 11; the circumferential stopper 20 is brought into contact with the molding surface 11 by the pushing member 30, and pressurizes the material to be solidified on the molding surface 11 to perform press solidification.

The product produced by the molding device according to an embodiment of the present invention may be a thin-walled structural component, further a thin-walled annular component, and the shape of the molding surface 11 may be matched with the corresponding shape of the product produced. For example, as shown in fig. 3, the shape of the prepared coupling ring 100 may be the same as the shape of the molding surface 11 of the core mold 10 as the shape of the inner surface of the coupling ring 100, and a material to be solidified may be laid on the annular side surface of the core mold 10, and after the material is solidified, the coupling ring 100 having the same cavity shape as the core mold 10 may be prepared.

In one embodiment, referring to fig. 1, the molding device includes a housing 40 and a cover 50, the housing 40 has a cavity, the mandrel 10, the plurality of circumferential stoppers 20 and the plurality of pushing members 30 are disposed in the cavity of the housing 40, and the cover 50 is disposed on the plurality of circumferential stoppers 20, the plurality of pushing members 30 and the housing 40.

In one embodiment, the shell 40 includes a bottom 41 and a side 42 connected to the bottom 41, and the cavity is surrounded by the bottom 41 and the side 42, and the core mold 10 is disposed on the bottom 41.

In one embodiment, the core mold 10 includes an upper surface, a lower surface, and a side surface connecting the upper surface and the lower surface, and the side surface is a molding surface 11, that is, in operation, a material to be cured is disposed on the side surface of the core mold 10, and after the material is cured and molded, the inner surface of the connecting ring 100 is attached to the outer surface (molding surface 11) of the core mold 10. Further, the molding surface 11 of the core mold 10 may have a ring shape, and the upper and lower surfaces of the core mold 10 have a circular shape.

In one embodiment, a plurality of circumferential stoppers 20 are provided on the outer periphery of the core mold 10 and are capable of moving in the radial direction of the annular core mold 10 by an external force. In operation, the circumferential stopper 20 is pressed against the core mold 10 by the pushing member 30, and the material to be solidified is sandwiched between the circumferential stopper 20 and the core mold 10.

In one embodiment, the peripheral stop 20 includes oppositely disposed first and second sides, the first side being adapted to act on the molding surface 11 of the core 10 and the second side being adapted to contact the push member 30. The shape of the first side may match the shape of the molding surface 11 so that the circumferential stop 20 does not disrupt the shape of the material to be cured when pressed against the molding surface 11 by the first side.

In one embodiment, the core mold 10 is annular, the circumferential stoppers 20 are arc-shaped bodies, and the plurality of circumferential stoppers 20 are uniformly disposed around the core mold 10, and the number of circumferential stoppers 20 may be 2, 3 or 4, for example.

In one embodiment, the circumferential stopper 20 is disposed on the bottom 41, and further, a positioning member 21 is disposed on the bottom 41, and the circumferential stopper 20 is disposed on the positioning member 21. The positioning component 21 can movably position the circumferential stop block 20 on a specific movement track so as to avoid deviation of the circumferential stop block 20 during movement; further, the positioning member 21 may be a positioning groove.

In one embodiment, the pushing member 30 includes a third side and a fourth side disposed opposite to each other, and the pushing member 30 acts on the circumferential block 20 through the third side, and further, the pushing member 30 contacts the second side of the circumferential block 20 through the third side.

In one embodiment, the third side is a chamfer, such as an arcuate chamfer, and the angle between the third side and the axis of the core 10 can be 10 to 30, such as 12, 15, 18, 20, 22, 25, 28. Further, the cross section of the push member 30 in the direction parallel to the axis of the core mold 10 includes a side on the third side, and the angle between the side and the axis of the core mold 10 may be 10 to 30 °, for example, 12 °, 15 °, 18 °, 20 °, 22 °, 25 °, 28 °. If the included angle is larger than the range of 10-30 degrees, excessive friction force can be caused in the pressing process, and the operation among the components is affected; if the pressure is less than 10-30 degrees, the applied hoop pressure is too small, and the compactness and the molding quality inside the product can be affected.

In one embodiment, the shape of the third side matches or is identical to the shape of the second side of the circumferential stop 20; further, the cross section of the circumferential stopper 20 in the direction parallel to the axis of the core mold 10 includes a side on the second side, and the angle between the side and the axis of the core mold 10 may be 10 to 30 °, for example, 12 °, 15 °, 18 °, 20 °, 22 °, 25 °, 28 °.

In one embodiment, the pushing member 30 is a wedge, and specifically, the pushing member 30 has an inverted trapezoid shape in cross section in a direction parallel to the axis of the core mold 10. The inverted trapezoid includes an upper base adjacent to the cover 50, a lower base adjacent to the bottom 41, and a first side (waist) and a second side (waist) connecting the upper base and the lower base, wherein the length of the upper base is greater than that of the lower base, the first side is located on the third side, and the second side is located on the fourth side.

In one embodiment, the pushing member 30 is disposed between the side portion 42 and the circumferential stop 20, the pushing member 30 is connected to the side portion 42 through the fourth side surface, the pushing member 30 is movably disposed on the side portion 42, for example, the pushing member 30 is disposed on the side portion 42 through the cooperation of the protrusion and the groove; further, a guide groove is provided on the fourth side, a boss 421 matching the guide groove is provided on the side 42, and the guide groove and the boss 421 may extend along the length direction of the second side. The arrangement of the guide groove and the boss 421 can realize the positioning of the pushing component 30 in the moving process.

In an embodiment, the pushing members 30 are arc-shaped bodies, for example, the third side and the fourth side are arc-shaped surfaces, the pushing members 30 may be uniformly disposed around the circumferential stoppers 20, and the number of the pushing members 30 may be the same as the number of the circumferential stoppers 20.

In an embodiment, the pushing member 30 and the circumferential block 20 are both arc-shaped bodies, and the arc-shaped body of the pushing member 30 and the arc-shaped body of the circumferential block 20 have the same circle center; further, the core mold 10 has an axis, and the center of the arc of the pushing member 30 and the center of the arc of the circumferential stopper 20 are both located on the axis of the core mold 10.

In the molding device according to an embodiment of the present invention, during operation, the core mold 10 on which the material to be cured is laid is first disposed on the bottom 41 of the shell 40, and then the plurality of circumferential stoppers 20 are disposed around the core mold 10 by the positioning members 21, and a certain gap is provided between the circumferential stoppers 20 and the core mold 10; after that, the pushing member 30 is pushed up and down along the boss 421 into the cavity between the side portion 42 and the circumferential stopper 20 by the pressing of the cover 50. Along with the downward movement of the pushing member 30 in the vertical direction, a radial force in the horizontal direction near the core mold 10 is provided to the circumferential stopper 20, and the circumferential stopper 20 moves toward the core mold 10 along the positioning member 21 and contacts the core mold 10 while pressurizing the material to be cured, thereby achieving mold-pressing curing of the material.

In the molding device of the embodiment of the invention, in the pressurizing process of the pushing component 30 of the cover body 50, the pushing component 30 is driven to move towards the molding surface 11, so that downward pressure is converted into annular acting force, the annular uniform pressurizing of the connecting ring 100 is realized, the uniform stability of quality is improved, the further discharge of solvent micromolecules in the high-temperature curing process is facilitated under the action of pressure, the porosity in the product is reduced, and the compactness and molding quality of the product are improved.

In one embodiment, after the to-be-pushed member 30 is pressed against the core mold 10 by the circumferential stoppers 20, a first gap is formed between two adjacent circumferential stoppers 20, and a second gap is formed between two adjacent pushing members 30, and the first gap is in communication with the second gap. Further, each first gap communicates with a second gap to form a gap 60, and one or more gaps 60 are formed between the core 10 and the side 42. Still further, the first gap and the second gap have the same axis, for example, the first gap and the second gap may be bar-shaped gaps having the same width and the same axis, so that the gap 60 becomes a linear bar-shaped gap. The width of the gap 60 may be 0.3 to 0.5mm. The arrangement of the gap 60 can provide an exhaust passage, which is beneficial to the discharge of small molecules in the high-temperature curing process, reduces the porosity in the product and improves the internal quality of the product.

In one embodiment, a plurality of through holes 411 are formed on the bottom 41, after the material is solidified into a product, the pushing member 30 can be ejected out of the shell 40 through the through holes 411, and then the circumferential stopper 20 is removed, and the core mold 10 is taken out. Preferably, the projection of the through hole 411 in the axial direction of the core mold 10 is located within the area of the corresponding projection of the pushing member 30.

In an embodiment, the positioning of the pushing component 30 can be effectively realized by the arrangement of the guide groove, so that the pushing component 30 can only move along a reserved track in the pressurizing process, and the pushing component 30 further pushes the circumferential stop block 20 to move towards the forming surface 11, thereby realizing uniform circumferential pressurizing of the product; on the other hand, the guide groove has a positioning and demolding effect, and in the reverse ejection process through the through hole 411, the pushing part 30 can only move along a reserved track due to the demolding guide effect, so that the problem of jamming caused by angle change is effectively avoided, and the quality and demolding efficiency of a product are improved.

The molding apparatus according to an embodiment of the present invention further includes a stripper ring 12, and the stripper ring 12 has a ring-shaped structure that can be disposed outside the core mold 10.

In one embodiment, stripper ring 12 is annular and surrounds the bottom of core 10 with its upper profile conforming to the end surface of the bottom of coupler ring 100.

After the compression molding solidification is completed, the product is tightly attached to the core mold 10, and the end face of one side of the product is directly knocked to force the other side to release the product in the prior art, so that layering defects of the product are easily caused. In one embodiment of the invention, the force bearing area can be increased by knocking the demoulding ring 12, and the axial direction acting force is indirectly applied to the product, so that the effective demoulding of the product can be realized, and the internal quality of the product is effectively ensured.

In one embodiment, the material to be cured may be a polyimide composite material, such as a polyimide prepreg containing a modified polyimide Z-pin, which is prepared by dipping fibers in a polyimide hybrid glue solution and by a pultrusion process.

The invention provides a preparation method of a high-temperature-resistant polyimide composite material connecting ring, which comprises the following steps:

s1: device design and manufacture:

the core mold 10 is designed according to the external dimensions and structural characteristics of the coupling ring 100.

S2: layering of prepregs:

after preheating the core mold 10, layering polyimide prepreg on the molding surface 11 of the core mold 10 according to a designed layering mode, and vacuumizing at a certain temperature to remove the solvent in advance.

S3: mold filling and curing

The preform after the pre-solvent removal is subjected to edge trimming, the core mold 10 with the preform is set in the molding apparatus shown in fig. 1 and 2, and after the preform reaches the pressing point, the pushing member 30 is pushed by the cover 50 to move the circumferential stopper 20 toward the core mold 10, thereby being cured by pressing.

S4: demolding

After the apparatus cools to room temperature, the cover 50 is opened, the pushing member 30 is ejected, the circumferential stopper 20 and the core mold 10 are taken out, the product of the connecting ring 100 is taken out from the core mold 10, and surface finishing is performed.

The molding device of the embodiment of the invention can be used for compression molding of products and can improve the internal quality of the prepared products.

According to the embodiment of the invention, through the optimal design of the forming device, the uniform circumferential pressurization is effectively realized, and the prepared connecting ring has the advantages of high bearing strength, compact and reliable internal quality, low porosity, high dimensional accuracy, flat internal and external surface quality and uniform and stable performance.

The molding apparatus and the use thereof according to an embodiment of the present invention will be further described below with reference to the drawings and examples.

Examples

Mixing 100 parts by weight of YH-550 thermosetting polyimide resin, 1 part by weight of negative expansion filler beta-eucryptite and 150 parts by weight of organic solvent, and performing ultrasonic treatment at room temperature for 4 hours to prepare polyimide mixed glue solution; adding the polyimide mixed glue solution into a glue dipping tank of a pultrusion machine, dipping carbon fiber M40J into the polyimide mixed glue solution, and preparing modified polyimide Z-pin with the diameter of 0.5mm, the polyimide content of 30%, the beta-eucryptite content of 0.3% and the carbon fiber content of 69.97% through a pultrusion process. The modified polyimide Z-pin is implanted into the M40J/YH-550 polyimide prepreg by ultrasonic, and the volume fraction of the modified polyimide Z-pin is 1.5%.

The obtained polyimide prepreg containing the modified polyimide Z-pin is subjected to compression molding solidification in the forming device, and the specific process comprises the following steps:

the preheated core 10 is laminated by using M40J/YH-550 polyimide prepreg, and the following laminating direction is adopted: and (5) performing solvent pre-removal by a vacuum bag method after layering, heating to 240 ℃ for 2h, performing local trimming after cooling, performing compression molding and curing by a molding device shown in figures 1 and 2, wherein the curing process is that the temperature is heated to 180 ℃ for 1h, the temperature is kept for 1h at 240 ℃, the temperature is then heated to 350 ℃, the temperature is kept for 20min, the pressure is increased to 3-5 MPa, the temperature is then increased to 370 ℃, the temperature is kept for 3h, cooling is started, demoulding is performed after cooling, and then the product is placed in a high-temperature oven for 2h of aftertreatment at 400 ℃.

CT detection of the prepared polyimide composite material connecting ring shows that no delamination and loosening defects are found, and the result is shown in figure 4.

Carrying out a normal temperature static strength test and a static heat combined test on the high temperature resistant polyimide, wherein the structure of the connecting ring is kept complete under 120% of use load in the normal temperature static strength test; the results of the static heat combined test show that the breaking load of the connecting ring under the severe temperature load of 520 ℃ is 12.45kN (120% of the using load), and the design requirement of the heat strength is met.

The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention.

Claims (10)

1. A molding apparatus comprising:

a core die comprising a molding surface for providing a material to be solidified;

a plurality of circumferential stops movably disposed around the mandrel; and

and a plurality of pushing members for pushing the plurality of circumferential stoppers to move in a direction approaching the molding surface.

2. The molding apparatus of claim 1, wherein the circumferential stop includes oppositely disposed first and second sides, the circumferential stop pressing against the molding surface through the first side and receiving pressure from the pushing member through the second side.

3. The molding apparatus of claim 2, wherein the pushing member includes third and fourth oppositely disposed sides, the third side for acting on the second side; the third side face is an inclined face, and the shape of the second side face is matched with that of the third side face.

4. The molding apparatus of claim 1, wherein the pushing member is a wedge; and/or the number of the groups of groups,

the molding device comprises a shell and a cover body, wherein the shell is provided with a cavity, and the core mold, the plurality of circumferential stop blocks and the plurality of pushing components are all arranged in the cavity.

5. The molding apparatus of claim 4, wherein a positioning member is provided on the housing, the circumferential stop being provided on the positioning member and being capable of approaching or moving away from the molding surface along a specific path by the positioning member.

6. The molding apparatus of claim 4, wherein a boss is provided on the housing, a guide groove is provided on the pushing member, or a guide groove is provided on the housing, a boss is provided on the pushing member; the guide groove is sleeved on the boss, and the pushing component can enter or leave the shell along a specific route under the action of the boss and the guide groove.

7. The molding apparatus according to claim 4, wherein a plurality of through holes are provided in the housing, and projections of the through holes in an axial direction of the core mold are located within a region of projections of the pushing member in the axial direction of the core mold.

8. The molding apparatus of any one of claims 1 to 7, wherein the plurality of pushing members press the core mold through the plurality of circumferential stoppers with a first gap formed between adjacent two of the circumferential stoppers and a second gap formed between adjacent two of the pushing members, the first gap being in communication with the second gap; and/or the number of the groups of groups,

the pushing component and the circumferential stop block both comprise arc-shaped bodies, and the circle centers of the arc-shaped bodies of the pushing component and the circumferential stop block are positioned on the same straight line.

9. The molding apparatus of any one of claims 1 to 8, further comprising a stripper ring for stripping the cured product from the mandrel, the stripper ring being disposed outside the mandrel.

10. A molding method comprising press-curing molding using the molding apparatus according to any one of claims 1 to 9, the method comprising the steps of:

paving a material to be solidified on the molding surface of the core mold; and

the molding surface is pressurized by the pushing components and the circumferential stoppers so as to cure and mold the material to be cured.