Composite material hollow guide vane forming die and manufacturing method

Abstract

A composite material hollow guide vane forming die comprises a bottom die and a pressing die, the bottom die is fixedly arranged, the pressing die can move relative to the bottom die, and the pressing die and the bottom die jointly define a forming space of a composite material hollow guide vane. Wherein the bottom die comprises a core die, the core die comprises an expansion body, the circumferential surface of the expansion body is configured to be an annular laying supporting face, and the expansion body enables the laying supporting face to expand in the radial direction. The mold can provide uniform pressure from inside to outside for the prefabricated body in the forming process, the uniformity of forming pressure distribution is improved, the prefabricated body is fully compacted, the quality defect caused by dimensional deviation or thermal expansion performance difference is avoided, and the part performance is improved. The invention further provides a manufacturing method of the composite hollow guide vane.

Description

Technical Field

[0001] The invention belongs to the field of aeroengines, and in particular relates to a composite material hollow guide vane forming die and a manufacturing method. Background Art

[0002] Ceramic matrix composites (CMC) have the advantages of light weight, high strength, high service temperature and good corrosion resistance, and have been increasingly used in aircraft engines. The hollow turbine guide vanes of aircraft engine stators are one of the typical application scenarios of CMC materials. Usually, the manufacturing process of hollow guide vanes is: CMC materials such as fiber unidirectional tapes or fiber fabrics are wound and laid on the surface of the core mold to form a preform, and then the preform is extruded and limited by a die, and finally the finished blades are obtained through processes such as curing and sintering. In this process, since the CMC material laying process usually requires adhesion through slurry, and there is a significant size difference between the radial outer contour surface of the preform and the core mold, the die cannot fully and evenly press the preform, which is easy to cause structural strength defects due to uneven compaction or form fiber wrinkles at the die joints, affecting the surface quality of the finished parts. Therefore, providing a molding die that can improve the quality of preform pressurization is of great value for improving the manufacturing quality of hollow guide vanes of aircraft engines. Summary of the invention

[0003] The purpose of the present invention is to provide a composite hollow guide vane forming die to improve the pressure forming effect of the hollow guide vane preform. The present invention also provides a composite hollow guide vane manufacturing method.

[0004] According to an embodiment of one aspect of the present invention, there is provided a composite hollow guide vane forming mold, comprising a base mold and a pressure mold, wherein the base mold is fixedly arranged, and the pressure mold can move relative to the base mold, and the base mold and the pressure mold together define a forming space for the composite hollow guide vane, wherein the core mold comprises an expansion body, the circumferential surface of the expansion body is configured as an annular paving support surface, and the expansion body can expand radially to expand radially under the paving support surface.

[0005] By setting up an expandable core mold, the composite material preform can be supported outward from the inside during the hollow guide vane forming process, forming a uniform support effect on the composite material preform and improving the compaction state of the composite material layer. At the same time, the expandable core mold can compensate for the thermal mismatch between the bottom mold, the composite material preform and the die during the sintering process, avoiding dimensional deviation of the finished material geometry due to different thermal expansion coefficients.

[0006] Furthermore, in some embodiments, the expansion body includes a plurality of circumferentially arranged core modules, and surfaces of the plurality of core modules jointly form the draping support surface. When the draping support surface radially expands, gaps between the plurality of core modules increase.

[0007] Furthermore, in some embodiments, the core modules are connected by flexible materials to isolate the internal space enclosed by the core modules from the external space. The flexible connecting material can ensure that the relative positions of the core blocks do not deviate, and prevent the external composite material from invading the internal space enclosed by the core modules to affect the operation of the expansion body.

[0008] Furthermore, in some embodiments, the expansion body includes an expansion mechanism, and the expansion mechanism includes one or more combinations of a mechanical expansion mechanism, a hydraulic expansion mechanism, a pneumatic expansion mechanism, or a supporting structure that can expand or deform at a certain temperature.

[0009] Furthermore, in some embodiments, the bottom mold further includes mold seats disposed at both ends of the core mold, and the mold seats are provided with edge plate molding surfaces for edge plate molding of the composite hollow guide vane.

[0010] Furthermore, in some embodiments, the core mold further includes a connecting section, and the connecting section is arranged on both axial sides of the paving support surface to allow the core mold to be connected to the mold.

[0011] Further, in some embodiments, the die includes an end die and a middle die, the end die includes a first end die and a second end die respectively arranged at two axial ends of the core die, and the middle die is arranged between the first end die and the second end die. The end die can be used to form the end and edge plate portion of the blade body, and the middle die is used to form the middle section of the blade body and provide pressure for the end die.

[0012] Furthermore, in some embodiments, the cross-section of the middle die is configured to be a wedge shape that gradually expands from one end close to the core die to one end away from the core die, so as to allow the middle die to exert a pushing action on the first end die and the second end die away from each other when applying molding pressure.

[0013] According to an embodiment of another aspect of the present invention, there is provided a method for manufacturing a composite hollow guide vane, which adopts the composite hollow guide vane forming mold provided in any of the aforementioned embodiments and includes the following steps: providing a composite material paving material, paving the composite material paving material on the core mold to form a composite material preform; applying molding pressure and limiting the composite material preform by the pressing mold; pushing the paving support surface to expand by the expansion structure; curing and sintering, removing the composite material hollow guide vane forming mold, and obtaining a composite material hollow guide vane finished product.

[0014] Furthermore, in some embodiments, the composite material paving material includes unidirectional tape or fiber fabric, and the composite material paving material includes one or more combinations of carbon / silicon carbide, silicon carbide / silicon carbide, zirconium boride / silicon carbide, silicon dioxide, aluminum oxide, and SiCN. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 An exploded view of a composite hollow guide vane forming mold structure in one embodiment;

[0016] Figure 2 An exploded view of the bottom mold structure in one embodiment;

[0017] Figure 3 It is a schematic diagram of the assembly of the core mold and the end pressing mold in one embodiment;

[0018] Figure 4 A schematic diagram of the assembly of a die in one embodiment;

[0019] Figure 5 This is a schematic structural diagram of the assembly state of a composite hollow guide vane forming mold in one embodiment;

[0020] Figure 6a This is a schematic diagram of the structure of the core mold before expansion in one embodiment;

[0021] Figure 6b This is a schematic diagram of the structure of the core mold after expansion in one embodiment;

[0022] Figure 7a This is a schematic diagram of the structure of the core mold before expansion in another embodiment;

[0023] Figure 7b This is a schematic diagram of the structure after the core mold is expanded in another embodiment;

[0024] Figure 8 It is a schematic diagram of the cross-sectional structure of a composite hollow guide vane forming mold in another embodiment.

[0025] The purpose of the above drawings is to explain the present invention in detail so that those skilled in the art can understand the technical concept of the present invention. For the sake of simplicity, the above drawings only schematically illustrate structures related to the technical features of the present invention, and do not strictly illustrate the complete structure and all details in accordance with the actual proportion. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0027] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The phrase appearing in various locations in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive independent or alternative embodiments. Those skilled in the art should be able to understand that the embodiments herein may be combined with other embodiments without causing structural conflicts.

[0028] In the description of this article, unless otherwise clearly specified and limited, the technical terms "installed", "connected", "connected" and the like should be understood in a broad sense, which can be a movable connection, a fixed connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0029] In the description of this document, terms indicating orientation or positional relationships, such as "up", "down", "left", "right", "horizontal", "vertical", "height", "length", and "width", are intended to accurately describe the embodiments and simplify the description, but are not intended to limit the parts or structures involved to have a specific orientation, be installed or operate in a specific orientation, and should not be construed as a limitation on the embodiments in this document.

[0030] In the description of this article, the terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating relative importance or limiting the quantity, specific order or primary and secondary relationship of the described technical features. In the description of this article, the meaning of "plurality" is at least two.

[0031] In order to solve the problems of uneven preform molding pressure distribution and inconsistent strength and surface quality caused by poor size matching between the bottom mold, the pressure mold and the preform during the molding process of composite hollow guide vanes in aircraft engines, and inconsistent thermal expansion properties, an embodiment of the present invention provides a composite hollow guide vane molding mold and a manufacturing method thereof.

[0032] The exploded diagram of the molding die structure is shown in Figure 1 As shown, it includes a bottom mold and a pressure mold, wherein the bottom mold is fixedly arranged, including a left mold base 1, a right mold base 2 and a core mold 3; the pressure mold can move relative to the bottom mold and apply molding pressure, including a left pressure mold 4 as an end pressure mold, a right pressure mold 5 and a middle pressure mold 6.

[0033] In different embodiments, the die can be divided into multiple sub-components according to the specific structure of the guide vane. Figure 1As shown, the die is divided into two parts: the pressure surface sub-component and the suction surface sub-component, specifically including the suction surface left die 4S, the suction surface right die 5S, the suction surface middle die 6S, the pressure surface left die 4P, the pressure surface right die 5P and the pressure surface middle die 6P. Among them, the suction surface die sub-component and the pressure surface die sub-component limit the suction surface and the pressure surface of the guide vane respectively, jointly define the edge plates at both ends of the guide vane, and provide molding pressure. In other embodiments, a leading edge sub-component or a trailing edge sub-component may also be provided to apply molding pressure to the guide vane preform.

[0034] The structure of the bottom mold is as follows Figure 2 As shown, the core mold 3 is provided with connecting sections 31 and 32 at both axial ends, which can be respectively inserted into the slots 13 and 23 on the left mold base 1 and the right mold base 2 for connection, and then fastened by inserting bolts into the bolt holes 12 and 21, so as to assemble the bottom mold into a whole. The middle part of the core mold 3 is an expansion body that can expand circumferentially. The surface of the expansion body is an annular paving support surface 37, which is used to form the hollow inner contour surface of the guide vane. After the bottom mold is assembled, the paving support surface 37 and the edge plate support surfaces 17 and 27 on the left mold base 1 and the right mold base 2 together form the support surface for the composite material paving. Figure 3 (The left mold base 1 and the right mold base 2 are not shown), CMC composite material is laid, wound or laid layer by layer on the support surface. In different embodiments, the material can be made of unidirectional tape, fiber fabric or other fillers. The material of the material can be made of one or more combinations of carbon / silicon carbide, silicon carbide / silicon carbide, zirconium boride / silicon carbide, silicon dioxide, aluminum oxide, SiCN, etc. to make a composite material preform 7. The slider 41 on the left die 4 and the slider 52 on the right die 5 can respectively cooperate with the slide groove 14 on the left die base 1 and the slide groove 25 on the right die base 2, so that the left die 4 and the right die 5 can be inserted into the left die base 1 and the right die base 2; combined Figure 4 , Figure 5 The sliders 61 and 62 on the middle die 6 can respectively cooperate with the slide groove 16 of the left die base 1 and the slide groove 26 of the right die base 2, so that the middle die 6 can be inserted between the left die 4 and the right die 5, and connected with the left die base 1 and the right die base 2. The assembled composite hollow guide vane forming mold structure is shown in FIG. Figure 5 As shown, the left die 4, the right die 5, and the middle die 6 jointly define the profile of the guide vane under the guidance and limiting action of the above-mentioned multiple groups of sliders and slide grooves. Finally, fastening bolts are installed in the bolt holes 60 of the middle die 6 to fix the die. After the die assembly is completed, the core mold 3 can expand radially, so that the covering support surface 37 can evenly compact the preform 7 from the inside to the outside, eliminating the problems of uneven molding pressure distribution and insufficient compaction caused by size differences.

[0035] In some embodiments, depending on the different structural features of the guide vane, the mold base can also be set as a composite mold including multiple mold sub-components to better achieve the paving of the material; or one of the left mold base 1 or the right mold base 2 can be set as an integrated structure with the core mold 3 to reduce the number of parts and simplify the assembly process.

[0036] In a preferred embodiment, if Figure 4 As shown, the cross-sectional shape of the middle die 6 is a wedge-shaped structure with a narrow end 672 close to the core die 3 and a gradually widened end away from the core die 3. The two side surfaces 64 and 65 of the wedge-shaped structure are respectively in contact with the left die 4 and the right die 5. After the fastening bolts are installed in the bolt holes 60, the middle die 6 exerts a pushing action on the left die 4 and the right die 5 to move away from each other, so as to achieve the following Figure 3 The end 672 of the middle die 6, together with the left die 4 and the right die 5, applies molding pressure to the blade section 72 of the preform 7.

[0037] During the molding process, the draping molding surface 37 can expand radially under the action of the expansion body, providing pressure from the inside to the outside for the preform 7. This ensures that even if there is a certain mismatch between the guide vane molding space formed by the compression mold and the bottom mold before the core mold 3 expands and the size of the preform 7, or the thermal expansion properties of the bottom mold and the compression mold are not completely matched, the core mold 3 can still apply uniform and sufficient molding pressure to the preform after expansion, thereby improving the compaction state of the preform 7 and improving the mechanical properties and uniformity of the guide vane finished product.

[0038] In one embodiment, Figure 6a As shown, the middle section of the core mold 3 is configured as an expansion core 300 made of thermal expansion material. Figure 1 The draping molding surface 37 shown is the outer surface of the expansion core 300. The expansion core 300 itself serves as an expansion mechanism. During the heating and curing process of the CMC preform (in some embodiments, the curing temperature is 160° C.-500° C.), the expansion core 300 is heated and expanded. Figure 6b As shown, the volume increases to become the expanded core 310, and uniform compression is applied to the preform 7 from the inside to the outside, so that the preform can be fully compacted.

[0039] In another embodiment, Figure 7aAs shown, the core mold 3 includes a plurality of circumferentially arranged core modules 301, and the paving molding surface 37 is formed by the outer surfaces of these core modules 301, and the expansion mechanism (not shown) is arranged in the cavity 303 surrounded by the core modules 301. The core modules 301 are connected by a connecting material 302 with a certain flexibility, so as to isolate the expansion mechanism from the space outside the core mold 3 to avoid the paving material from invading the cavity 303 and interfering with the normal operation of the expansion mechanism during the manufacturing process. Before the core mold 3 expands, the connecting material 302 is folded inward and stored in the cavity 303 surrounded by the core modules 301 to avoid the connecting material 302 and the paving material from interfering with each other. During the molding process, Figure 7b As shown, the expansion mechanism drives each core module 301 to move radially outward, the gap between the core modules 301 increases, and the connection 302 is stretched and expanded to maintain the relative position relationship between the core modules 301 unchanged to avoid deviation in the size of the finished product. The core module 301 pushes outward to apply uniform molding pressure to the preform 7 so that the preform can be fully compacted. In different embodiments, the expansion mechanism for pushing the core module 301 can adopt different structures. In some embodiments, an electrically driven mechanical expansion structure such as an umbrella rib structure can be adopted, and a mechanical expansion structure such as an umbrella rib structure can also be adopted. Figure 8 As shown, a hydraulic or pneumatic expansion mechanism is arranged in the cavity 303, and pressure is provided by an external pressure source 8 to drive the movement of the expansion mechanism. In some embodiments, the expansion mechanism can also be arranged as a support structure made of shape memory alloy, and the expansion mechanism is in a compressed state under low temperature conditions, and the expansion mechanism is expanded to push the core module 301 when heated.

[0040] After the core mold 3 expands, the curing and sintering of the preform 7 is completed, and after cooling, the composite hollow guide vane forming mold is removed to obtain a CMC hollow guide vane finished product.

[0041] By using the composite hollow guide vane forming mold provided in the above embodiment, on the one hand, it is possible to provide a sufficiently uniform forming pressure to the CMC preform to compact the preform uniformly, thereby improving the structural uniformity and overall mechanical properties of the finished guide vane; on the other hand, since the dimensional deviation between the preform 7 and the forming surface formed by the mold can be compensated by the expansion of the core mold 3, there is no need for excessive pressure between the preform 7 and the die before sintering after the preform 7 is paved and formed, and the molding surface of the preform 7 can be close to the molding surface formed by the die without exceeding it, thereby avoiding wrinkles caused by the paving and the extrusion of the die, which affects the surface quality of the finished product.

[0042] The purpose of the above embodiments is to further explain the present invention in detail in conjunction with the accompanying drawings so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, the optimization or equivalent replacement of the part structures and method steps involved, as well as the combination of implementation methods in different embodiments without conflict of structure and principle, all fall within the protection scope of the present invention.

Claims

1. A composite hollow guide vane forming mold, comprising a bottom mold and a pressure mold, wherein the bottom mold is fixedly arranged, the pressure mold can move relative to the bottom mold, and the bottom mold and the pressure mold jointly define a forming space for the composite hollow guide vane, characterized in that: The bottom mold includes a core mold, and the core mold includes an expansion body. The circumferential surface of the expansion body is configured as an annular paving support surface. The expansion body can expand radially to make the paving support surface expand radially.

2. The composite hollow guide vane forming mold according to claim 1, characterized in that: The expansion body includes a plurality of core modules arranged circumferentially, and surfaces of the plurality of core modules jointly form the draping support surface. When the draping support surface radially expands, gaps between the plurality of core modules increase.

3. The composite hollow guide vane forming mold according to claim 2, characterized in that: The core modules are connected to each other via a flexible material to isolate the inner space enclosed by the core modules from the outer space.

4. The composite hollow guide vane forming mold according to any one of claims 1 to 3, characterized in that: The expansion body comprises an expansion mechanism, and the expansion mechanism comprises one or more combinations of a mechanical expansion mechanism, a hydraulic expansion mechanism, a pneumatic expansion mechanism, or a supporting structure capable of expansion or deformation at a certain temperature.

5. The composite hollow guide vane forming mold according to any one of claims 1 to 3, characterized in that: The bottom mold also includes mold seats arranged at both ends of the core mold, and the mold seats are provided with edge plate molding surfaces for edge plate molding of the composite hollow guide vane.

6. The composite hollow guide vane forming die according to any one of claims 1 to 3, characterized in that: The core mold further comprises a connecting section, and the connecting section is arranged on both axial sides of the paving support surface to allow the core mold to be connected to the mold.

7. The composite hollow guide vane forming mold according to claim 6, characterized in that: The die comprises an end die and a middle die, wherein the end die comprises a first end die and a second end die respectively arranged at two axial ends of the core die, and the middle die is arranged between the first end die and the second end die.

8. The composite hollow guide vane forming mold according to claim 7, characterized in that: The cross section of the middle die is set to be a wedge shape that gradually expands from one end close to the core die to one end away from the core die, so as to allow the middle die to exert a pushing action on the first end die and the second end die away from each other when applying molding pressure.

9. A method for manufacturing a composite hollow guide vane, characterized in that: A composite hollow guide vane forming mold as claimed in any one of claims 1 to 8 is used, and the following steps are included: Providing a composite material pavement, and spreading the composite material pavement on the core mold to form a composite material preform; Applying molding pressure to the composite material preform and limiting the position by the pressing die; Expanding the expansion body to expand the paving support surface and evenly compact the preform; After solidification and sintering, the composite hollow guide vane forming mold is removed to obtain a composite hollow guide vane finished product.

10. The method for manufacturing a hollow guide vane according to claim 9, characterized in that: The composite material paving material comprises a unidirectional tape or a fiber fabric, and the composite material paving material comprises one or more combinations of carbon / silicon carbide, silicon carbide / silicon carbide, zirconium boride / silicon carbide, silicon dioxide, aluminum oxide, and SiCN.

Images