Manufacturing method of anchor bolt nuts and anchor bolt nuts

Abstract

This invention provides a method for manufacturing an anchor nut and the anchor nut itself. The manufacturing method comprises: Step S1, winding prepreg tape onto the surface of a threaded mandrel to form a prepreg tape layer; Step S2, winding prepreg filaments onto the surface of the prepreg tape layer to form a prepreg filament layer; Step S3, winding prepreg sheet onto the surface of the prepreg filament layer to form a prepreg sheet layer, thus obtaining a prefabricated assembly; Step S4, molding the prefabricated assembly to obtain the anchor nut. This application, by winding prepreg tape, prepreg filaments, and prepreg sheet onto the surface of a threaded mandrel to form a prepreg tape layer, a prepreg filament layer, and a prepreg sheet layer arranged sequentially from the inside out, and subsequently molding the resulting anchor nut, effectively increases the strength and stiffness of the thread through different layup sequences to prevent slippage, while also effectively increasing the radial load of the nut.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and more specifically, to a method for manufacturing an anchor nut and the anchor nut itself. Background Technology

[0002] Rock bolts are the main support equipment in coal mine roadways. Due to their advantages such as non-metallicity, good durability, light weight, and low production cost, composite rock bolts are gradually replacing steel rock bolts in coal mine applications. Currently, ordinary fiberglass rock bolt nuts are generally molded from short-cut glass fiber reinforced bulk molding compound (BMC), resulting in low nut strength. During use, this leads to low load-bearing capacity at the connection between the fiberglass rock bolt tail and the nut, reducing the overall strength of the rock bolt. Rock bolt nut failure mainly manifests as the internal thread of the nut or the external thread section of the rock bolt being flattened and failing under shear stress, or the nut being deformed, cracked, or crushed by the support plate. The main reasons for failure are poor thread strength and stiffness, and low shear resistance of the nut thread, leading to nut pull-out and failure.

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] The main objective of this invention is to provide a method for manufacturing anchor bolt nuts and an anchor bolt nut in order to solve the problems of poor thread strength and stiffness, low shear resistance of the nut thread and failure caused by the pull-out of ordinary fiberglass anchor bolt nuts in the prior art.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for manufacturing an anchor nut is provided, the method comprising the following steps: step S1, winding a prepreg tape onto the surface of a threaded bar to form a prepreg tape layer; step S2, winding a prepreg bundle onto the surface of the prepreg tape layer to form a prepreg bundle layer; step S3, winding a prepreg sheet onto the surface of the prepreg bundle layer to form a prepreg sheet layer, thereby obtaining a prefabricated assembly; step S4, molding the prefabricated assembly to obtain an anchor nut; wherein the prepreg tape comprises a first fiber fabric and a first matrix resin attached to the first fiber fabric, the prepreg bundle comprises a fiber bundle and a second matrix resin attached to the fiber bundle, and the prepreg sheet layer comprises a fiber sheet and a third matrix resin attached to the fiber sheet.

[0006] Further, in step S1, the first fiber fabric is a carbon fiber fabric or a glass fiber fabric, and the areal density of the first fiber fabric is 150-250 g / m³. 2 .

[0007] Furthermore, the carbon fibers in the carbon fiber fabric have a tensile strength of 4600–4900 MPa and a tensile modulus of 230–250 GPa.

[0008] Furthermore, the tensile strength of the glass fiber is 3300–3700 MPa, and the tensile modulus is 90–100 GPa.

[0009] Furthermore, the width of the prepreg tape is 40–50 mm.

[0010] Furthermore, the prepreg tape is multi-layered.

[0011] Furthermore, with the central axis of the threaded mandrel as a reference, the winding direction of the prepreg tape is 40-50°.

[0012] Furthermore, in the prepreg tape, the mass content of the first fiber fabric is 40-55%.

[0013] Furthermore, the fiber bundles are carbon fiber bundles or glass fiber bundles.

[0014] Furthermore, the fiber bundle specifications are 24K to 48K.

[0015] Furthermore, the prepreg bundle layer is multi-layered.

[0016] Furthermore, with the central axis of the threaded mandrel as a reference, the winding angle of the prepreg bundle is 40–50° or 85–95°.

[0017] Furthermore, the mass content of the fiber bundle in the prepreg is 40-55%.

[0018] Further, in step S3, the fiber sheet includes a second fiber fabric and chopped fibers. The chopped fibers are laid on the second fiber fabric to form a chopped fiber layer. The second fiber fabric is a carbon fiber fabric or a glass fiber fabric with an areal density of 150–250 g / m². 2 The short-cut fibers are glass fibers or carbon fibers with a diameter of 6–13 μm.

[0019] Furthermore, the mass ratio of chopped fibers to second fiber fabric is 0.6-1:1.5-2.

[0020] Furthermore, the width of the prepreg sheet is 30–40 mm.

[0021] Furthermore, the fiber sheet content in the prepreg sheet is 40-55% by mass.

[0022] Further, in step S4, the molding temperature is 135–1450℃, the pressure is 15–25MPa, and the time is 10–20min.

[0023] Furthermore, the direction of the pressure applied is perpendicular to the central axis of the threaded mandrel.

[0024] Furthermore, the first matrix resin, the second matrix resin, and the third matrix resin are each independently an epoxy resin.

[0025] Furthermore, by weight percentage, the raw materials of epoxy resin include: 30-50% liquid bisphenol type epoxy resin, 10-30% polyfunctional epoxy resin, 20-40% solid epoxy E20 resin, 5-8% dicyandiamide, 3-5% organic urea accelerator, and 8-10% toughening agent, wherein the liquid bisphenol type epoxy resin is liquid bisphenol A type epoxy resin and / or bisphenol F type epoxy resin.

[0026] To achieve the above objectives, according to another aspect of the present invention, an anchor nut is provided, which is mainly prepared by any of the manufacturing methods provided in the first aspect.

[0027] Furthermore, the screw nut is frustum-shaped, and the taper of the anchor nut is 1:4 to 6, preferably 1:5.

[0028] Furthermore, the thread interface of the anchor nut is an arc with a radius of 6-7 mm, a thread height of 1.2-1.4 mm, and a thread width of 2.8-3.2 mm.

[0029] Furthermore, the concentricity tolerance of the anchor nut is ±0.1mm.

[0030] By applying the technical solution of this application, an anchor nut is formed by winding prepreg tape, prepreg bundles, and prepreg sheets onto the surface of a threaded mandrel to create a prepreg tape layer, a prepreg bundle layer, and a prepreg sheet layer arranged sequentially from the inside out. This is followed by compression molding to obtain the anchor nut. The different layup sequences of this anchor nut effectively increase the strength and stiffness of the thread to prevent slippage, while also effectively increasing the radial load of the nut. Furthermore, by using a prepreg sheet layer as the outer layer, the anchor nut can be given a certain degree of deformation capacity while meeting the nut's strength requirements. This allows the anchor nut to grip the anchor rod body tightly under the compression of the pallet, further increasing the overall load-bearing capacity of the anchor assembly. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0032] As analyzed in the background section of this application, current ordinary fiberglass anchor nuts are molded using ordinary glass fiber reinforced bulk molding compound. These nuts have poor thread strength and stiffness, and low shear resistance. During use, problems arise such as the internal thread of the nut or the external thread of the anchor bolt being flattened and failing under shear stress, and the nut being deformed, cracked, or crushed by the support plate. To solve this problem, this application provides a method for manufacturing an anchor nut and an anchor nut itself.

[0033] In one typical embodiment of this application, a method for manufacturing an anchor nut is provided, the method comprising the following steps: step S1, winding a prepreg tape around the surface of a threaded mandrel to form a prepreg tape layer; step S2, winding a prepreg bundle around the surface of the prepreg tape layer to form a prepreg bundle layer; step S3, winding a prepreg sheet around the surface of the prepreg bundle layer to form a prepreg sheet layer, thereby obtaining a prefabricated assembly; step S4, molding the prefabricated assembly to obtain an anchor nut; wherein, the prepreg tape comprises a first fiber fabric and a first matrix resin attached to the first fiber fabric; the prepreg bundle comprises a fiber bundle and a second matrix resin attached to the fiber bundle; and the prepreg sheet comprises a fiber sheet and a third matrix resin attached to the fiber sheet.

[0034] By applying the technical solution of this application, an anchor nut is formed by sequentially winding prepreg tape, prepreg filaments, and prepreg sheets onto the surface of a threaded mandrel to create a prepreg tape layer, a prepreg filament layer, and a prepreg sheet layer arranged from the inside out. This is followed by compression molding to obtain the anchor nut. The different layup sequences of this anchor nut effectively increase the strength and stiffness of the thread to prevent slippage, while also effectively increasing the radial load of the nut. Furthermore, by using a prepreg sheet layer as the outer layer, the anchor nut can be given a certain degree of deformation capacity while meeting the nut's strength requirements. This allows the anchor nut to grip the anchor rod body tightly under the compression of the pallet, further increasing the overall load-bearing capacity of the anchor assembly.

[0035] The specific types of the first matrix resin, second matrix resin, and third matrix resin are not specifically limited; any commonly used resin types in the art are acceptable. To further improve the strength of the anchor nut, it is preferable that the first matrix resin, second matrix resin, and third matrix resin are each independently epoxy resin.

[0036] Specifically, in some embodiments, the epoxy resin raw materials, by weight percentage, include: 30-50% liquid bisphenol type epoxy resin (e.g., 30%, 35%, 40%, 42%, 45%, 48%, 50%, or any range of two values), 10-30% multifunctional epoxy resin (e.g., 10%, 15%, 20%, 25%, 30%, or any range of two values), and 20-40% solid epoxy E20 resin (e.g., 20%, 25%, 30%, 32%, 35%, 38%, 40%, or any range of two values). The range of values ​​is defined as follows: dicyandiamide 5-8% (e.g., 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8% or any range of values); organic urea accelerator 3-5% (e.g., 3%, 3.5%, 4%, 4.5%, 5% or any range of values); toughening agent 8-10% (e.g., 8%, 8.5%, 9%, 9.5%, 10% or any range of values); wherein, the liquid bisphenol type epoxy resin is liquid bisphenol A type epoxy resin and / or bisphenol F type epoxy resin.

[0037] The specific type of the above-mentioned multifunctional epoxy resin is not limited, including but not limited to at least one of 4,4′-diaminodiphenylmethane tetraglycidylamine, triglycidyl p-aminophenol, and 4,5-epoxyhexane-1,2-dicarboxylic acid diglycidyl ester.

[0038] The specific type of the above-mentioned organic urea accelerator is not limited, including but not limited to at least one of phenyl dimethylurea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and N,N-(methylenedi-4,1-phenylene)bis(N,N-dimethylurea).

[0039] The specific type of toughening agent is not limited, including but not limited to at least one of carboxyl-terminated nitrile rubber, nano-core-shell rubber particles, polyurethane-modified epoxy resin, and polysulfide rubber.

[0040] In step S1 above, the first fiber fabric in the prepreg tape is preferably carbon fiber fabric or glass fiber fabric to further improve the strength of the prepreg tape, and thus further improve the strength of the anchor nut. In some embodiments, the areal density of the first fiber fabric is preferably 150-250 g / m³. 2 For example, 150g / m 2 180g / m 2 200g / m 2 250g / m 2Or a range of values ​​composed of any two values. The specific type of carbon fiber in the above-mentioned carbon fiber fabric is not limited; any carbon fiber commonly used in the art can be used. In some embodiments, the selected carbon fiber has a tensile strength of 4600–4900 MPa and a tensile modulus of 230–250 GPa, to facilitate higher strength of the prepreg tape formed by the adhesion of the first matrix resin to the carbon fiber fabric woven therefrom. The specific type of glass fiber in the above-mentioned glass fiber fabric is also not limited; any glass fiber commonly used in the art can be used. In some embodiments, the selected glass fiber has a tensile strength of 3300–3700 MPa and a tensile modulus of 90–100 GPa.

[0041] To facilitate the winding of prepreg tape onto the threaded mandrel, the preferred width of the prepreg tape is 40–50 mm (e.g., 40 mm, 42 mm, 45 mm, 48 mm, 50 mm, or any combination of two values). If the width of the prepreg tape is too small, the winding process becomes more complex, and it is difficult to form a prepreg tape layer of uniform thickness. If the width of the prepreg tape is too large, it is not conducive to winding onto the threaded mandrel.

[0042] There is no specific limit to the number of layers of the prepreg tape mentioned above. Depending on the needs of the anchor nut, it can be one layer or multiple layers. When the prepreg tape layer is multiple layers, it is more conducive to improving the strength of the threads in the anchor nut.

[0043] To further enhance the strength of the prepreg tape layer, it is preferable that when winding the prepreg tape onto the threaded mandrel, the winding direction of the prepreg tape is 40-50° with the central axis of the threaded mandrel as a reference. This further enhances the strength and stiffness of the thread and also increases the radial load on the nut. In some embodiments, the prepreg tape is first wound three layers clockwise on the surface of the threaded mandrel, and then three layers counterclockwise are wound on the surface of the threaded mandrel.

[0044] In step S2 above, in order to further improve the strength of the fiber bundle layer, it is preferable that the fibers in the fiber bundle are carbon fiber or glass fiber.

[0045] The specific specifications of the aforementioned fiber bundles are not limited. In some embodiments, the specifications of the fiber bundles are 24K to 48K, which is more conducive to improving the thread strength of the anchor nut.

[0046] The prepreg bundle layer has at least one layer. To further improve the strength of the anchor nut, it is preferable that the prepreg bundle layer has multiple layers.

[0047] To improve the efficiency of prepreg winding, it is preferable to use the central axis of the threaded mandrel as a reference, with the winding direction of the prepreg bundle at 40–50° or 85–95°, to further enhance the strength and stiffness of the thread, while also increasing the radial load on the nut. In some embodiments, the prepreg bundle is wound circumferentially around the outer surface of the prepreg tape layer to form a prepreg bundle layer, preferably with five layers.

[0048] In step S3 above, the fiber sheet includes a second fiber fabric and chopped fibers. The chopped fibers are laid on the second fiber fabric layer to form a chopped fiber layer, that is, the fiber sheet includes a second fiber fabric and chopped fibers stacked together; wherein, the second fiber fabric is a carbon fiber fabric or a glass fiber fabric with an areal density of 150-250 g / m³. 2 The chopped fibers are glass fibers with a diameter of 6–13 μm (e.g., 6, 8, 10, 11, or 13 μm). Preferably, the mass ratio of chopped fibers to the second fiber fabric in the fiber sheet is 0.6–1:1.5–2 (e.g., 0.6:1.5, 0.6:1.8, 0.6:2, 0.8:1.5, 0.8:1.8, 0.8:2, 1:1.5, 1:1.8, or 1:2), and the prepreg sheet formed from this fiber sheet has superior mechanical strength.

[0049] To facilitate the winding of the prepreg sheet onto the outer surface of the prepreg bundle layer to form the prepreg sheet layer, the width of the prepreg sheet is preferably 30-40 mm (e.g., 30 mm, 32 mm, 35 mm, 38 mm, 40 mm, or any range of two values).

[0050] To further improve the strength of the anchor nut, in some embodiments, the prepreg tape contains 40-55% by mass; such as 40%, 45%, 50%, 55%, or any combination of two values. In other embodiments, the prepreg tow contains 40-55% by mass; such as 40%, 45%, 50%, 55%, or any combination of two values. In still other embodiments, the prepreg sheet contains 40-55% by mass; such as 40%, 45%, 50%, 55%, or any combination of two values.

[0051] In step S4 above, the specific process conditions for compression molding are not limited, and commonly used compression molding conditions in the art are acceptable. To further improve the efficiency of compression molding, it is preferred that the compression molding temperature be 135-145℃ (e.g., 135℃, 138℃, 140℃, 142℃, 145℃ or any range of two values), the pressure be 15-25MPa (e.g., 15MPa, 18MPa, 20MPa, 22MPa, 25MPa or any range of two values), and the time be 10-20min (e.g., 10min, 12min, 15min, 18min, 20min or any range of two values).

[0052] When ordinary fiberglass anchor nuts are compression molded using chopped glass fiber reinforced bulk molding compound (BMC), the mold cavity is placed vertically. During vertical pressure application, the material around the threaded mandrel is compacted vertically, but the material pressure is lower in the horizontal direction, resulting in poor strength of the anchor thread after molding. In some embodiments, the direction of pressure application is perpendicular to the central axis of the threaded mandrel, which can improve the strength of the anchor thread after molding while ensuring thread compaction. Preferably, the anchor nut cavity is horizontally arranged, and the pressure is applied vertically between the upper and lower pressure heads of the threaded mandrel and the mold during compression molding.

[0053] It should be noted that the nut prepared by the manufacturing method of the anchor nut provided in this application can be any shape commonly used in the art. In order to improve its compatibility with the anchor, it is preferred to be a frustum-shaped pallet nut with the small diameter part as the head and the large diameter part as the tail. When the prepreg yarn is wound around the prepreg tape layer, the number of layers is increased sequentially from the head to the tail to form a frustum-shaped structure.

[0054] In a second typical embodiment of this application, an anchor nut is also provided, which is mainly prepared according to any of the manufacturing methods provided in the first typical embodiment described above.

[0055] The anchor nut provided in this application is provided with a prepreg tape layer, a prepreg filament layer, and a prepreg sheet layer from the inside out. By setting different layup sequences, the strength and stiffness of the thread are effectively increased to prevent slippage, while also effectively increasing the radial load of the nut. In addition, by using a prepreg sheet layer as the outer layer, the anchor nut is given a certain degree of deformation capacity while meeting the strength requirements. This allows the anchor nut to grip the anchor rod body tightly under the compression of the pallet, further increasing the overall load-bearing capacity of the anchor assembly.

[0056] In some embodiments, the anchor nut is frustum-shaped, i.e., a tray nut, with a taper of 1:4 to 6, more preferably 1:5, to further improve its compatibility with the anchor rod, so that the nut can grip the anchor rod body under the compression of the tray, thereby increasing the overall load-bearing capacity of the anchor rod assembly.

[0057] In some embodiments, the contact length between the anchor nut and the tray hole is 10-15 mm shorter than the height of the tray hole.

[0058] In other embodiments, the thread interface of the anchor nut is an arc with a radius of 6-7 mm, a thread height of 1.2-1.4 mm, and a thread width of 2.8-3.2 mm, in order to enhance the compatibility with the anchor bolt while further improving the tightness of the anchor bolt assembly, thereby increasing the overall load-bearing capacity of the anchor bolt assembly.

[0059] In some embodiments, the concentricity tolerance of the anchor nut is ±0.1mm, resulting in more stable and reliable quality.

[0060] The beneficial effects of this application will be further illustrated below with reference to embodiments and comparative examples.

[0061] Example 1

[0062] This embodiment provides a frustum-shaped anchor nut, which is prepared according to the following steps:

[0063] (1) A prepreg tape is provided. The prepreg tape is cut into narrow strips with a width of 40-50 mm. The narrow strips are first wound three times clockwise and then three times counterclockwise around the surface of the threaded mandrel to form a prepreg tape layer covering the threaded mandrel. The prepreg tape includes carbon fiber twill fabric and epoxy resin attached to the surface of the carbon fiber twill fabric. The areal density of the carbon fiber twill fabric is 200 g / m³. 2 The raw materials for the epoxy resin include: 40wt% liquid bisphenol A type epoxy resin, 15wt% polyfunctional epoxy resin, 25% solid epoxy E20 resin, 7% dicyandiamide, 4% phenyl dimethyl urea, 9% carboxyl-terminated butadiene nitrile rubber, and the content of carbon fiber twill fabric in the prepreg tape is 45wt%.

[0064] (2) Provide a prepreg bundle, with the central axis of the threaded mandrel as the reference, the prepreg bundle is wound three times on the outer surface of the prepreg tape layer along the winding direction of 45±5°, and then wound three times along the winding direction of -45±5°, and then the prepreg bundle is wound five times in a circumferential direction; with the small diameter part of the anchor nut as the head and the large diameter part as the tail, the prepreg bundle is wound ten times at the tail to form a frustum shape, thus obtaining a prepreg bundle layer; wherein the prepreg bundle includes fiber bundles and epoxy resin attached to the fiber bundles, the epoxy resin being the same as the epoxy resin on the prepreg tape, the fiber bundles being 24K carbon fiber bundles with a tensile strength of 4700Mpa and a tensile modulus of 240GPa, and the content of carbon fiber bundles in the prepreg bundle layer being 45wt%.

[0065] (3) Provide a prepreg sheet, cut the prepreg sheet into a prepreg sheet strip with a width of 30-40 mm, and wrap the prepreg sheet strip circumferentially around the outer surface of the prepreg fiber bundle layer, wrapping three layers to form a prepreg sheet layer, thereby obtaining a prefabricated assembly; wherein, the prepreg sheet includes a fiber sheet and epoxy resin attached to the fiber sheet, the epoxy resin being the same as the epoxy resin on the prepreg strip, the fiber sheet being composed of a continuous fiber fabric and randomly oriented chopped short fibers, the continuous fiber fabric having an areal density of 200 g / m². 2 The carbon fiber fabric has chopped carbon fiber with a diameter of 6-7 μm and a length of 30-50 mm. The mass ratio of chopped fiber to carbon fiber fabric is 1:1.5. The fiber sheet content in the prepreg is 45 wt%. The total mass of the prefabricated assembly is 180 g.

[0066] (4) Place the prefabricated assembly into the anchor nut mold. The mold has six cavities, and the cavities are placed horizontally. The mold temperature is controlled at 140±3℃. Then, apply pressure vertically to the cavities at a pressure of 20MPa and hold the pressure for 15 minutes. After holding the pressure, remove the part from the cavity, cool it, and trim the edges to obtain a frustum-shaped anchor nut.

[0067] Example 2

[0068] The difference between this embodiment and Embodiment 1 is that the carbon fiber twill fabric content in the prepreg tape is 40 wt%, the carbon fiber tow content in the prepreg tow is 40 wt%, and the fiber sheet content in the prepreg sheet is 40 wt%.

[0069] Example 3

[0070] The difference between this embodiment and Embodiment 1 is that the carbon fiber twill fabric content in the prepreg tape is 55 wt%, the carbon fiber tow content in the prepreg tow is 55 wt%, and the fiber sheet content in the prepreg sheet is 55 wt%.

[0071] Example 4

[0072] The difference between this embodiment and embodiment 1 is that in step (2), glass fiber bundles are used to replace carbon fiber bundles as fiber bundles in the prepreg bundles, and the tensile strength of the glass fiber bundles is 3500 MPa and the tensile modulus is 95 GPa.

[0073] Example 5

[0074] The difference between this embodiment and Embodiment 1 is that, in step (1), the prepreg tape uses a glass fiber plain weave fabric instead of a carbon fiber twill fabric, and the areal density of the glass fiber plain weave fabric is 200 g / m². 2 .

[0075] Example 6

[0076] The difference between this embodiment and Embodiment 1 is that, in step (1), the areal density of the carbon fiber twill fabric in the prepreg tape is 150 g / m². 2 .

[0077] Example 7

[0078] The difference between this embodiment and Embodiment 1 is that, in step (1), the areal density of the carbon fiber twill fabric in the prepreg tape is 250 g / m². 2 .

[0079] Example 8

[0080] The difference between this embodiment and Embodiment 1 is that, in step (1), the prepreg tape uses a surface density of 300 g / m³. 2 The glass fiber plain weave fabric replaces the carbon fiber fabric; in step (2), the glass fiber bundle replaces the carbon fiber bundle as the fiber bundle in the prepreg bundle, and the tensile strength of the glass fiber bundle is 3500 MPa and the tensile modulus is 95 Gpa.

[0081] Example 9

[0082] The difference between this embodiment and embodiment 1 is that in step (3), the mass ratio of carbon fiber fabric to chopped fiber in the fiber sheet is 0.6:1.5.

[0083] Example 10

[0084] The difference between this embodiment and embodiment 1 is that in step (3), the fiber sheet is a carbon fiber fabric, and no short-cut fibers are set on the carbon fiber fabric.

[0085] Example 11

[0086] The difference between this embodiment and embodiment 1 is that in step (2), the prepreg yarn is first wound three layers on the outer surface of the prepreg tape layer at a winding angle of 60±5°, and then wound three layers along the winding direction of -60±5°.

[0087] Example 12

[0088] The difference between this embodiment and embodiment 1 is that in step (2), the prepreg yarn is first wound three layers on the outer surface of the prepreg tape layer at a winding angle of 30±5°, and then wound three layers along the winding direction of -30±5°.

[0089] Example 13

[0090] The difference between this embodiment and embodiment 1 is that in step (4), the mold cavity is placed vertically while the direction of pressure application remains unchanged.

[0091] Comparative Example 1

[0092] The difference between this comparative example and Example 1 is that step (3) was not performed. In step (2), the prepreg bundles were wound in multiple layers to obtain a prefabricated assembly with a total mass of 180g.

[0093] Comparative Example 2

[0094] The difference between this comparative example and Example 1 is that step (2) was not performed. In step (1), the prepreg tape was wound in three layers and the prepreg sheet was wound in multiple layers to obtain a prefabricated assembly with a total mass of 180g.

[0095] Comparative Example 3

[0096] The difference between this comparative example and Example 1 is that step (1) was not performed. In step (2), the pre-filament bundle was wound in six layers and the prepreg sheet was wound in multiple layers to obtain a prefabricated assembly with a total mass of 180g.

[0097] Test case

[0098] The anchor nuts provided in the above embodiments and comparative examples were subjected to maximum load-bearing capacity and toughness tests, and the results are shown in Table 1 below. The maximum load-bearing capacity test method was MTT 1061-2008 Resin Anchor Bolt Glass Fiber Reinforced Plastic Rod Body and Accessories. The results are shown in Table 1 below.

[0099] Table 1

[0100]

[0101]

[0102] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: by winding prepreg tape, prepreg bundle, and prepreg sheet onto the surface of a threaded mandrel to form a prepreg tape layer, a prepreg bundle layer, and a prepreg sheet layer arranged sequentially from the inside out, and then molding the resulting anchor nut, the anchor nut effectively increases the strength and stiffness of the thread through different layup sequences to prevent slippage, while also effectively increasing the radial load of the nut. Furthermore, by using a prepreg sheet layer as the outer layer, the anchor nut can also provide a certain degree of deformation capacity while meeting the nut's strength requirements, thereby enabling the anchor nut to grip the anchor rod body tightly under the compression of the pallet, further increasing the overall load-bearing capacity of the anchor assembly.

[0103] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of manufacturing an anchor nut, characterized by, The manufacturing method comprises the following steps: Step S1, winding a prepreg tape on the surface of the threaded mandrel to form a prepreg tape layer; Step S2, winding a prepreg tow on the surface of the prepreg tape layer to form a prepreg tow layer; Step S3, winding a prepreg sheet on the surface of the prepreg tow layer to form a prepreg sheet layer, to obtain a preform assembly; Step S4, performing die forming on the preform assembly to obtain the anchor rod nut. The prepreg tape comprises a first fiber fabric and a first matrix resin attached to the first fiber fabric, the prepreg tow comprises a fiber tow and a second matrix resin attached to the fiber tow, and the prepreg sheet comprises a fiber sheet and a third matrix resin attached to the fiber sheet.

2. The manufacturing method according to claim 1, characterized by, The step S1, the first fiber fabric is carbon fiber fabric or glass fiber fabric, the areal density of the first fiber fabric is 150~250g / m 2 .

3. The manufacturing method according to claim 2, wherein the carbon fiber in the carbon fiber fabric has a tensile strength of 4600-4900 MPa and a tensile modulus of 230-250 GPa; and / or the glass fiber in the glass fiber fabric has a tensile strength of 3300-3700 MPa and a tensile modulus of 90-100 GPa. The prepreg tape has a width of 40-50 mm. The prepreg tape layer is a plurality of layers.

4. The production method according to claim 1, characterized by The prepreg tape is wound at an angle of 40-50° with respect to the central axis of the threaded mandrel. The first fiber fabric has a mass content of 40-55% in the prepreg tape. The fiber tow is a carbon fiber tow or a glass fiber tow. The fiber tow has a specification of 24K-48K. The prepreg tow layer is a plurality of layers.

5. The production method according to claim 1, wherein The prepreg tow is wound at an angle of 40-50° or 85-95° with respect to the central axis of the threaded mandrel. The fiber tow has a mass content of 40-55% in the prepreg tow.

7. The manufacturing method according to claim 6, wherein the mass ratio of the chopped fiber to the second fiber fabric is 0.6-1:1.5-2.

8. The manufacturing method according to claim 1, wherein the prepreg sheet has a width of 30-40 mm. The fiber sheet has a mass content of 40-55% in the prepreg sheet.

6. The production method according to claim 1, characterized by The step S3, the fiber sheet comprises a second fiber fabric and chopped fibers, the chopped fibers are laid on the second fiber fabric to form a chopped fiber layer, the second fiber fabric is a carbon fiber fabric or a glass fiber fabric, the areal density is 150-250 g / m 2 The chopped fibers are glass fibers or carbon fibers, and the diameter is 6-13 μm. The die forming is performed at a temperature of 135-145°C, a pressure of 15-25 MPa, and for a time of 10-20 min.

10. The manufacturing method according to claim 9, wherein the pressure is applied in a direction perpendicular to the central axis of the threaded mandrel. The first matrix resin, the second matrix resin, and the third matrix resin are each independently an epoxy resin.

12. The manufacturing method according to claim 11, wherein the prepreg tape, the prepreg tow, and the prepreg sheet are each independently a plurality of layers. ​ 9. The production method according to claim 1, characterized by, ​ ​ ​ 11. The production method according to any one of claims 1 to 10, characterized by, ​ ​ The raw materials of the epoxy resin include, in percentage by mass: 30-50% of a liquid bisphenol-type epoxy resin, 10-30% of a multifunctional epoxy resin, 20-40% of a solid epoxy E20 resin, 5-8% of dicyandiamide, 3-5% of an organic urea accelerator, and 8-10% of a toughening agent, wherein the liquid bisphenol-type epoxy resin is a liquid bisphenol A-type epoxy resin and / or a bisphenol F-type epoxy resin.

13. An anchor nut, characterized in that The anchor rod nut is mainly prepared by the manufacturing method in any one of claims 1 to 12.

14. A rock bolt nut according to claim 13, characterised in that, The anchor rod nut is in the shape of a circular truncated cone, and the taper of the anchor rod nut is 1:4-6.

15. A rock bolt nut according to claim 14, characterised in that, The taper of the anchor rod nut is 1:

5.

16. The anchor nut of claim 13, wherein, The interface of the thread of the anchor rod nut is a circular arc, the radius of the circular arc is 6-7 mm, the height of the thread is 1.2-1.4 mm, and the width of the thread is 2.8-3.2 mm.

17. A rock bolt nut according to any one of claims 13 to 16, characterised in that, The concentricity tolerance of the anchor rod nut is ±0.1 mm.

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