Assembling method for butt joint of composite material part and metal part and preparation method of shaft

Abstract

According to the method for assembling the composite material part in butt joint with the metal part, the metal part provides a first installation face, the composite material part provides a second installation face, a microstructure with array-shaped protrusions is prepared on the first installation face, the microstructure is a shape memory alloy, and the microstructure deforms to be in a non-protruding state under the first condition; restoring to the protruding state under the second condition; the second mounting surface is provided with a sacrificial fiber fabric layer, the sacrificial fiber fabric layer comprises array-shaped gaps, and the array-shaped gaps correspond to the array-shaped protrusions; butting the first mounting surface and the second mounting surface under the first condition; and enabling the butted first mounting surface to be in a second condition, and enabling the bulges of the microstructure to be recovered and inserted into the array-shaped gaps. The invention further provides a preparation method of the shaft. According to the method, enough connection strength can be provided, and damage to the composite part is avoided.

Description

Technical Field

[0001] The present invention relates to the field of composite materials, and in particular to the field of methods for preparing composite material parts. Background Art

[0002] As a core component of rotating machinery, the drive shaft plays a very important role in the power system of aviation, automobiles and ships. Its main function is to transfer torque and energy between the engine and the output shaft. The use of advanced composite materials to prepare the drive shaft can bring significant performance advantages, such as improving the natural frequency of the drive shaft, avoiding resonance, achieving supercritical design, reducing vibration and noise, reducing energy loss in the transmission system, good wear resistance, and corrosion resistance.

[0003] Composite drive shafts are usually composed of composite shaft tubes and metal joints. Conventional connection methods, such as interference fit and bolt connection, can easily cause local damage to the composite material, destroy the connection strength, and reduce the load-bearing capacity of the drive shaft. Local damage can also cause problems such as reduced fatigue life and oil leakage. Summary of the invention

[0004] An object of the present invention is to provide an assembly method for joining a composite material part to a metal part, which can provide sufficient connection strength and avoid damage to the composite material part.

[0005] In an assembly method for butting a composite material part against a metal part, the metal part provides a first mounting surface, and the composite material part provides a second mounting surface, the first mounting surface and the second mounting surface are opposite to each other, and the assembly method includes the following steps: preparing a microstructure with array-like protrusions on the first mounting surface, wherein the microstructure is a shape memory alloy, and deforming the microstructure to a non-protruding state under a first condition and restoring the microstructure to a protruding state under a second condition; providing a sacrificial fiber fabric layer on the second mounting surface, wherein the sacrificial fiber fabric layer includes array-like gaps, and the array-like gaps correspond to the array-like protrusions; butting the first mounting surface under the first condition against the second mounting surface; placing the butted first mounting surface under the second condition, and restoring the protrusions of the microstructure and inserting them into the array-like gaps.

[0006] In one or more embodiments, the protrusions of the microstructure are arranged to have different extension directions.

[0007] In one or more embodiments, the top dimension of the protrusion is less than or equal to the bottom dimension.

[0008] In one or more embodiments, the protrusion is in the shape of a triangle and / or a cube and / or a frustum and / or a cone and / or a cuboid and / or a quadrangular pyramid.

[0009] In one or more embodiments, the array-shaped gaps are of unequal sizes, and the size of the protrusions is set to be larger than 1 mm and smaller than the length of a single gap in the warp extension direction or the weft extension direction of the sacrificial fiber fabric layer.

[0010] In one or more embodiments, the pitch of the microstructures is set to be a multiple of the gap length.

[0011] In one or more embodiments, the height of the protrusion is set to be no higher than the height of the sacrificial fiber fabric layer.

[0012] In one or more embodiments, the sacrificial fiber fabric layer also includes a resin portion, and the resin portion is distributed in the array-shaped gap; the method also includes the following steps: after each protrusion is inserted into the array-shaped gap, the second mounting surface and the first mounting surface are slowly moved relative to each other, and it is ensured that the protrusion does not separate from the array-shaped gap.

[0013] In one or more embodiments, the first condition is a first temperature or a first stress, and the second condition is a second temperature or a second stress.

[0014] In one or more embodiments, the composite material is made of carbon fiber, glass fiber, Kevlar fiber, polyimide fiber or SiC fiber.

[0015] In one or more embodiments, the composite material piece is manufactured by winding, braiding, weaving or sewing.

[0016] In one or more embodiments, the fabric structure of the sacrificial fiber fabric layer is satin weave, plain weave or twill weave.

[0017] In one or more embodiments, the sacrificial fiber fabric layer includes one or more layers of fiber fabric.

[0018] Another object of the present invention is to provide a method for preparing a shaft, which includes a composite shaft body and metal joints located at both ends of the shaft body, and an assembly method for connecting metal parts using the above-mentioned composite materials, wherein the inner circumferential surface of the metal joint is a first mounting surface, and the outer circumferential surfaces at both ends of the shaft body are second mounting surfaces.

[0019] In one or more embodiments, the step of preparing the shaft body includes: providing a forming core mold; first preparing a sacrificial fiber fabric layer at both ends of the forming core mold, and then winding or covering the fiber material for manufacturing the shaft body.

[0020] In one or more embodiments, the axial length of the sacrificial fiber fabric layer is not less than the axial length of the contact between the assembly surface of the shaft body and the metal joint.

[0021] In one or more embodiments, the circumference of the sacrificial fiber fabric layer is not less than the circumference of the forming core mold.

[0022] The above method uses memory alloy material to manufacture the microstructure on the surface of the metal part. The microstructure fits into the existing gap of the composite material to achieve fixation. This method minimizes assembly damage to the composite part and improves assembly reliability and engine safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0024] Figure 1 is a schematic diagram of a composite shaft with a metal joint;

[0025] Figure 2 It is the assembly schematic;

[0026] Figure 3A-3B Schematic diagram of a metal joint with microstructured protrusions;

[0027] Figure 4 It is a schematic diagram of the assembly position of the shaft body and the metal joint;

[0028] Figure 5 yes Figure 4 Enlarged view of point C in the middle;

[0029] Figure 6 is a schematic diagram of the matching state between the array-shaped gaps of the sacrificial fiber fabric layer and the array-shaped protrusions of the microstructure;

[0030] Figure 7 It is a flow chart of the assembly method of the composite material part butting the metal part;

[0031] Figure 8 is a flow chart of a method for preparing a shaft. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0033] It should be noted that these and other subsequent drawings are only examples and are not drawn to scale, and should not be used to limit the actual scope of protection required by the present invention.

[0034] When composite parts and metal parts need to be assembled and fixed, the traditional bolt fixing structure will cause damage to the composite parts. Figure 1 As shown, the composite shaft with a metal joint includes a shaft body 410 and metal joints 420 located at both ends. The shaft body 410 and the metal joints 420 are generally interference fit by bolts, but this connection method will destroy the connection strength, causing problems such as a decrease in the load-bearing capacity of the transmission shaft, affecting the connection strength.

[0035] The present invention discloses an assembly method for butting a composite material part against a metal part, which can provide sufficient fixing strength while ensuring requirements such as torque transmission and sealing, and does not cause damage to the composite material part.

[0036] Reference Figure 2 As shown, the metal component provides a first mounting surface 100 , and the composite component provides a second mounting surface 200 . The first mounting surface 100 and the second mounting surface 200 face each other to form an assembly surface.

[0037] Composite materials can be manufactured using carbon fiber, glass fiber, Kevlar fiber, polyimide fiber, SiC fiber, etc., by methods including but not limited to winding, braiding, weaving, stitching, etc.

[0038] This method is Figure 7 As shown, the following steps are included: S301. Prepare a microstructure with array-like protrusions on the first mounting surface, the microstructure is a shape memory alloy, and the microstructure is deformed to a non-protruding state under a first condition, and restored to a protruding state under a second condition; S302. Make the second mounting surface include a sacrificial fiber fabric layer, the sacrificial fiber fabric layer includes array-like gaps, and the array-like gaps correspond to the array-like protrusions; S303. Butt the first mounting surface under the first condition with the second mounting surface; S304. Make the first mounting surface after docking be in the second condition, so that the protrusions of the microstructure are restored and inserted into the array-like gaps.

[0039] Among them, steps 301 and 302 do not necessarily constitute a sequence.

[0040] Specifically, in step S301, a layer of shape memory alloy microstructure 101 is added to the metal surface of the metal part. Shape memory alloy refers to a material that restores a deformed structure to its original shape by adjusting characteristics including but not limited to temperature and stress.

[0041] The microstructure protrusion 102 of the shape memory alloy material is deformed to a non-protruding state under the first condition, and restored to a protruding state under the second condition. For example, a certain temperature / stress is uniformly applied to the first mounting surface 100 until the surface is smooth and uniform without obvious protrusions, and the temperature / stress at this time is the first condition; another temperature / stress is uniformly applied to the first mounting surface 100, and the microstructure protrudes again, and the temperature / stress at this time is the second condition.

[0042] In some embodiments, the protrusions 102 of the microstructure 101 are arranged to have different extension directions, such as Figure 2 This is because considering that the component bears loads in multiple directions such as torsion and axial direction, setting protrusion structures in different directions can improve the overall load-bearing performance of the connection.

[0043] The top size of the protrusion 102 is preferably smaller than or equal to the bottom size, including but not limited to being in the shape of a triangle and / or a cube and / or a frustum and / or a cone and / or a cuboid and / or a quadrangular pyramid as a whole.

[0044] The spacing of the microstructures is a multiple of the gap length, and the number, density and arrangement of the surface protrusions are determined according to design requirements.

[0045] In step S302, the second mounting surface 200 is provided with a sacrificial fiber fabric layer 210, and the sacrificial fiber fabric layer 210 includes warp threads 201, weft threads 202, and array-shaped gaps 203 woven from the warp threads 201 and the weft threads 203. That is, a fiber in the x direction and a fiber in the y direction of the fiber fabric constitute an interlacing point of the fiber fabric, and the area between the four interlacing points constitutes a gap of the fiber fabric.

[0046] The array-shaped gaps correspond to the array-shaped protrusions, preferably one-to-one, so that each protrusion distributed in the array can extend into the array-shaped gaps.

[0047] The fabric structure of the sacrificial fiber fabric layer 210 is a wrought weave, a plain weave, or a twill weave. Figure 2 and Figure 6 While one layer of fabric is shown, the sacrificial fabric layer 210 may also include multiple layers of fabric.

[0048] In some embodiments, the gap sizes of the array-like gaps are not equal, and the size of the protrusion 102 is set to be larger than 1 mm and smaller than the length in the extension direction of the warp 201 or the length in the extension direction of the weft 202 of a single gap 203 of the sacrificial fiber fabric layer 210, so that the protrusion can extend into the gap without causing damage to the fibers of the sacrificial fiber fabric layer 210 itself.

[0049] That is, 1mm≤the maximum size of the protrusion≤the length of a gap in the fabric in the direction of extension of the weft 202 (the length is equal to the length between adjacent warp 201), or the length of a gap in the direction of extension of the warp 201 (the length is equal to the length between adjacent weft).

[0050] Preferably, the height of the protrusion 102 in a direction perpendicular to the plane where the sacrificial fiber fabric layer 210 is located is set to be no higher than the height of the sacrificial fiber fabric layer 210 .

[0051] The spacing between the protrusions 102 of the microstructure is a multiple of the gap length, and the number, density and arrangement of the surface protrusions are determined according to design requirements.

[0052] After the first mounting surface 100 and the second mounting surface 200 are prepared, step S303 is performed to dock the first mounting surface 100 in the first condition with the second mounting surface 200. At this time, the first mounting surface 100 does not present a protruding state, so it can better contact with the second mounting surface 200.

[0053] Finally, step S304 is performed to place the first mounting surface 100 in a second condition after docking, so that the protrusions of the microstructure are restored and inserted into the array-shaped gap. Under the second condition, the protrusions 102 of the microstructure 101 made of shape memory alloy reappear.

[0054] In some embodiments, the sacrificial fiber fabric layer 210 also includes a resin portion, which plays a role in supporting and impregnating the fibers, and the resin portion is distributed in the array-shaped gap 203. After each protrusion is inserted into the array-shaped gap, the second mounting surface 200 and the first mounting surface 100 are slowly moved relative to each other, and the protrusion is ensured not to be separated from the array-shaped gap. The microstructure of the protrusion slowly rubs against the sacrificial fiber fabric layer 210. Compared with the warp 201, the weft 202 and other fibers, the resin portion is more fragile. Therefore, during the heating and rubbing process, the resin will first be slowly destroyed and worn away by the microstructure. The microstructure of the protrusion is inserted into the gap of the fiber fabric, and the resin in the gap is crushed. The microstructure further bites and jams with the fibers around the gap, so that the protrusion 102 is engaged in the gap 203 to achieve further fixation.

[0055] The above-mentioned assembly method utilizes the existing fiber fabric gaps in the composite material and realizes fixed bite through the coordination of array-like protrusions and gaps, which can significantly reduce the damage caused by assembly and ensure that the contact area at the assembly connection between metal parts and composite parts is larger, the bite is tighter, and the structural stability is higher.

[0056] Combined with the introduction of the above-mentioned method for assembling a composite material part and a metal part, a method for preparing a composite material shaft can also be understood, such as Figures 3A to 6As shown, the composite material shaft includes a composite material shaft body 410 and metal joints 420 located at both ends of the shaft body, the inner circumference of the metal joint 420 is the first mounting surface 100, and the outer circumferences at both ends of the shaft body 410 are the second mounting surfaces 200.

[0057] The steps of preparing the shaft body include: providing a forming core mold (not shown in the figure); preparing a sacrificial fiber fabric layer 210 at both ends of the forming core mold by winding or draping, and then winding or draping the fiber material for manufacturing the shaft body. The thickness of a single fiber fabric layer of the sacrificial fiber fabric layer 210 is preferably 1.5 mm.

[0058] The axial length of the sacrificial fiber fabric layer 210 is not less than the axial length of the contact between the shaft body and the assembly surface of the metal joint; the circumference of the sacrificial fiber fabric layer 210 is not less than the circumference of the forming core mold.

[0059] Use a suitable molding process and use heating, pressurization, vacuum or any other appropriate process methods to cure the resin, demould the cured composite shaft, and complete subsequent machining.

[0060] The metal joints 420 at both ends of the composite shaft are made of shape memory alloy material. A microstructure is set on the circumferential surface of the end of the metal joint, that is, the connection part of the metal joint and the composite shaft, and a certain number of protrusions 102 are arranged in an array shape according to a certain gap. The extension direction of the protrusions 102 can be different, such as the length direction of some protrusions is consistent with the extension direction of the warp of the fiber fabric, and the length direction of some protrusions is consistent with the extension direction of the weft of the fiber fabric.

[0061] After the microstructure is manufactured, a certain temperature / stress is uniformly applied to the surface of the metal joint until the surface is smooth and uniform, so that the microstructure is in the first condition and has no obvious protrusions for easy assembly.

[0062] The tolerance range of the outer diameter of the metal joint end without microstructure and the inner diameter of the composite shaft with the sacrificial fiber fabric layer 210 is 0 to 0.127 mm.

[0063] The metal joint 420 is slowly inserted into the end of the composite shaft body 410, and then the second condition is uniformly applied to the metal joint, such as uniformly heating the assembly parts of the two, and simultaneously rotating the metal joint and the composite shaft in reverse with a small amplitude and slowly.

[0064] The microstructure of the surface of the metal joint made of memory alloy will slowly recover under the second condition. The temperature / stress is continuously applied until the microstructure protrudes again. The protruding microstructure slowly rubs against the sacrificial fiber fabric layer 210 of the composite shaft until the protrusion is engaged in the gap between the fibers.

[0065] The composite material part of the shaft manufactured by the above method has less damage and better assembly reliability.

[0066] The present application uses specific words to describe the embodiments of the present application, such as "one embodiment", "an embodiment", and / or "some embodiments" to refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0067] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for assembling a composite material component and a metal component, wherein the metal component provides a first mounting surface, and the composite material component provides a second mounting surface, wherein the first mounting surface and the second mounting surface face each other. It is characterized in that The steps include: A microstructure with array-shaped protrusions is prepared on the first mounting surface, wherein the microstructure is a shape memory alloy, and the microstructure is deformed to a state without protrusions under a first condition, and restored to a protrusion state under a second condition; The second mounting surface is provided with a sacrificial fiber fabric layer, wherein the sacrificial fiber fabric layer includes array-shaped gaps, and the array-shaped gaps correspond to the array-shaped protrusions; butting the first mounting surface in the first condition with the second mounting surface; The first mounting surface after docking is placed in the second condition, so that the protrusions of the microstructure are restored and inserted into the array-shaped gap.

2. The method according to claim 1, It is characterized in that The protrusions of the microstructure are arranged to have different extending directions.

3. The method according to claim 1, It is characterized in that The top dimension of the protrusion is smaller than or equal to the bottom dimension.

4. The method according to claim 1, It is characterized in that The protrusion is in the shape of a triangle and / or a cube and / or a frustum and / or a cone and / or a cuboid and / or a quadrangular pyramid.

5. The method according to claim 1, It is characterized in that The sizes of the array-shaped gaps are not equal, and the size of the protrusions is set to be larger than 1 mm and smaller than the length of a single gap in the warp extension direction or the weft extension direction of the sacrificial fiber fabric layer.

6. The method according to claim 1, It is characterized in that The pitch of the microstructures is set to be a multiple of the gap length.

7. The method according to claim 1, It is characterized in that The height of the protrusion is set to be no higher than the height of the sacrificial fiber fabric layer.

8. The method according to claim 1, It is characterized in that The sacrificial fiber fabric layer further includes a resin portion, and the resin portion is distributed in the array-shaped gaps; The method further comprises the following steps: after each protrusion is inserted into the array-shaped gap, the second mounting surface and the first mounting surface are slowly moved relative to each other, and it is ensured that the protrusion does not separate from the array-shaped gap.

9. The method according to claim 1, It is characterized in that The first condition is a first temperature or a first stress, and the second condition is a second temperature or a second stress.

10. The method according to claim 1, It is characterized in that The composite material piece is made of carbon fiber, glass fiber, Kevlar fiber, polyimide fiber or SiC fiber.

11. The method according to claim 1, It is characterized in that The composite material piece is manufactured by winding, braiding, weaving or sewing.

12. The method of claim 1, It is characterized in that The fabric structure of the sacrificial fiber fabric layer is in the form of a satin weave, a plain weave, or a twill weave.

13. The method of claim 1, It is characterized in that The sacrificial fiber fabric layer includes one or more layers of fiber fabric.

14. A method for preparing a shaft, the shaft comprising a composite shaft body and metal joints located at both ends of the shaft body, It is characterized in that Using the assembly method for joining composite materials to metal parts as described in any one of claims 1 to 13, the inner circumferential surface of the metal joint is the first mounting surface, and the outer circumferential surfaces at both ends of the shaft body are the second mounting surfaces.

15. The preparation method according to claim 14, It is characterized in that The steps of preparing the shaft body include: Provide forming core mold; A sacrificial fiber fabric layer is first prepared at both ends of the forming core mold, and then the fiber material for manufacturing the shaft body is wound or covered.

16. The preparation method according to claim 15, It is characterized in that The axial length of the sacrificial fiber fabric layer is not less than the axial length of the contact between the assembly surface of the shaft body and the metal joint.

17. The preparation method according to claim 15, It is characterized in that The circumference of the sacrificial fiber fabric layer is not less than the circumference of the forming core mold.

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