KR20230139401A - Fiber reinforced composite material propellers for drone and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a fiber-reinforced composite propeller for drones, which comprises: a foam core with slots formed in the longitudinal direction; a first prepreg layer surrounding an outer surface of the foam core; a prepreg web formed in the longitudinal direction by penetrating the foam core in a direction perpendicular to the ground through the slots of the foam core, and whose upper and lower parts are continuously connected to the first prepreg layer; and a second prepreg layer surrounding an outer surface of the first prepreg layer. Through optimization of the orientation and lamination configuration of such fiber-reinforced composite materials, it is possible to provide a propeller and a manufacturing method thereof that can minimize weight and increase bending characteristics.

Description

Fiber-reinforced composite material propellers for drones and their manufacturing method {FIBER REINFORCED COMPOSITE MATERIAL PROPELLERS FOR DRONE AND MANUFACTURING METHOD THEREOF}

The present invention relates to a propeller and a method of manufacturing the same, and more specifically, to a fiber-reinforced composite material propeller for drones to which the fiber-reinforced composite material is applied and a method of manufacturing the same.

In general, unmanned aerial vehicles (UAVs) are called by various terms depending on the situation, purpose, and country, but they are called drones and do not have a pilot on board according to a pre-programmed program, but are guided by radio wave guidance or their own navigation system. It is a general term for an airplane or helicopter-shaped unmanned aerial vehicle that can be flown or controlled by a drone. In the early days, unmanned aerial vehicles were studied for military purposes as air force missile bombing practice objects, and the first unmanned aerial vehicle named 'Bug' was developed in the United States in the 1910s when World War I was in full swing. Recently, as commercial use has increased, including logistics transportation, agriculture, information and communication, disaster observation, and aerial photography, the value of its use in various fields is increasing.

The main performance of an unmanned aerial vehicle is determined by propeller performance and efficiency, motor efficiency, and battery. In particular, the propeller is a propulsion device that rotates by driving the engine or motor and generates thrust by changing momentum in a large amount of air. It is one of the key components that determines the performance of As a way to improve propellers, which have a significant impact on the performance of unmanned aerial vehicles, a method of manufacturing propellers from fiber reinforced plastic (FRP) is being researched and developed.

Fiber-reinforced plastic is a composite material that is lightweight yet has high mechanical properties and vibration absorption characteristics, and can improve flight control capabilities compared to metal propellers. Additionally, due to the low coefficient of thermal expansion, aerodynamic performance can be improved due to less geometric deformation due to temperature changes.

In order to actually apply these fiber-reinforced plastics to propellers, from a structural aspect, appropriate orientation and lamination of the fibers and the physical properties of the laminated material are needed, and from a manufacturing aspect, a method of manufacturing a propeller with low cost and uniform quality is required. . However, conventional technology lacks a technical solution to this problem. For example, Republic of Korea Patent Publication No. 10-2019-0008202 discloses a propeller made of carbon fiber, but only discloses that the propeller material is simply composed of carbon fiber, and the structure and structure for effectively applying carbon fiber to the propeller. The composition, etc. are not disclosed at all.

Republic of Korea Patent Publication No. 10-2019-0008202

The present invention was created to solve the problems of the prior art as described above. The problem that the present invention aims to solve is optimization of the orientation and stacking configuration of the fiber-reinforced composite material for a propeller composed of the fiber-reinforced composite material. The aim is to provide a propeller and a manufacturing method thereof that can minimize weight and increase bending characteristics.

The above and other objects and advantages of the present invention will become apparent from the following description of preferred embodiments.

The above purpose is to form a foam core with a slot formed in the longitudinal direction, a first prepreg layer surrounding the outer surface of the foam core, and a longitudinal layer that penetrates the foam core in a direction perpendicular to the ground through the slot of the foam core, and the upper This is achieved by a fiber-reinforced composite material propeller for drones, which includes a prepreg web whose lower portion is continuously connected to the first prepreg layer and a second prepreg layer surrounding the outer surface of the first prepreg layer.

Preferably, the first prepreg layer and the prepreg web include carbon fibers arranged in one direction, and the carbon fibers arranged in one direction are arranged at any one of 0 to 45 degrees in the direction perpendicular to the ground in the longitudinal direction of the propeller. It may have an angle.

Preferably, the second prepreg layer includes carbon fibers arranged in both directions, and may have an angle of -45 degrees/+45 degrees between the carbon fibers arranged in both directions.

Preferably, the thickness of the foam core may be 0.1 to 7 mm.

Preferably, the thickness of the first prepreg layer may be 0.3 to 0.7 mm, and the thickness of the second prepreg layer may be 0.1 to 0.3 mm.

Preferably, the width of the prepreg web may be 1 to 3 mm.

Preferably, the prepreg web may be formed of two or less.

Preferably, the flexural strength of the fiber-reinforced composite material propeller for drones may be 230 to 400 MPa.

Preferably, the bending rigidity of the fiber-reinforced composite material propeller for drones may be 40 to 60 GPa.

Preferably, the weight of the fiber-reinforced composite material propeller for drones may be 26 to 35 g, and the length may be 16 to 18 inches.

Preferably, the foam core may have two or fewer slots.

In addition, the above object is, in the method of manufacturing the fiber-reinforced composite material propeller for drones described above, the step of performing release treatment on the inside of the upper and lower propeller molds, the first prepreg layer, the second prepreg layer, and the prepreg web. Cutting the prepreg, forming a slot into which the prepreg web is inserted into the foam core, sequentially stacking the cut second prepreg layer and the first prepreg layer on the upper and lower molds, the laminated first prepreg layer 1. Locally arranging the prepreg web on the prepreg layer to correspond to the slot position, laminating the foam core on the first prepreg layer and the prepreg web, joining the upper mold and the lower mold, joining. This is achieved by a method of manufacturing a fiber-reinforced composite propeller for drones, which includes the steps of mounting the mold on a press, heating and pressurizing it, and demolding and trimming the molded propeller.

Preferably, the heating temperature in the heating and pressurizing step may be 120 to 150°C.

Preferably, the pressing pressure in the heating and pressurizing steps may be 0.1 to 10 MPa.

Preferably, it is performed before the heating and pressurizing steps. It may further include preheating the joined mold at a temperature of 80 to 100°C.

Preferably, the heating and pressurizing steps may be performed in two or more multi-stage pressing processes.

According to the fiber-reinforced composite material propeller for drones and its manufacturing method according to the present invention, high specific strength and specific rigidity can be achieved through the internal foam core and external prepreg structure.

In addition, through the arrangement direction of the reinforcing fibers considering the purpose and structure of the propeller and the prepreg web penetrating the foam core, it is possible to minimize the weight and at the same time maximize the bending characteristics.

However, the effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

Figure 1 is a cross-sectional view in the width direction of a fiber-reinforced composite propeller for drones according to an embodiment of the present invention.
Figure 2 is an enlarged view of portion A of Figure 1.
Figure 3 is a longitudinal cross-sectional view of the foam core of a fiber-reinforced composite material propeller for drones according to an embodiment of the present invention.
Figure 4 is a cross-sectional view in the width direction of a fiber-reinforced composite propeller for drones according to another embodiment of the present invention.
Figure 5 is a diagram for explaining a method of manufacturing a fiber-reinforced composite propeller according to an embodiment of the present invention.
Figure 6 is a flow chart showing a method of manufacturing a fiber-reinforced composite propeller according to an embodiment of the present invention.

With reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein.

In the drawing, the thickness is enlarged to clearly express various layers and areas. Throughout the specification, similar parts are given the same reference numerals. When a part of a layer, membrane, region, plate, etc. is said to be "on" another part, this includes not only being "directly above" the other part, but also cases where there is another part in between. Conversely, when a part is said to be “right on top” of another part, it means that there is no other part in between.

Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. In case of conflict, the present specification, including definitions, will control. Although methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, suitable methods and materials are described herein.

Hereinafter, the present invention will be described in detail with reference to the attached drawings.

Figure 1 is a cross-sectional view in the width direction of a fiber-reinforced composite material propeller for drones according to an embodiment of the present invention, Figure 2 is an enlarged view of portion A of Figure 1, and Figure 3 is a drone for drones according to an embodiment of the present invention. This is a longitudinal cross-sectional view of the foam core of a fiber-reinforced composite propeller.

Referring to Figures 1 to 3, the fiber-reinforced composite material propeller for drones according to an embodiment of the present invention includes a foam core 140, a first prepreg layer 110 surrounding the outer surface of the foam core 140, A prepreg web 120 and a first prepreg layer 110 are formed in the longitudinal direction by penetrating the foam core 140 in a direction perpendicular to the ground, and the upper and lower parts are continuously connected to the first prepreg layer 110. It includes a second prepreg layer 130 surrounding the outer surface of.

Among the components of the present invention, the foam core 140 is formed of a foam material, and a method of manufacturing the foam core separately and laminating the first prepreg layer 110, the prepreg web 120, and the second prepreg layer 130. can be used, and can also be formed by foaming the foam material directly within the propeller mold. As an example, the foam core 140 of the present invention is a sheet-shaped foam core inserted into the sheet-shaped foam on the first prepreg layer 110 and prepreg web 120 laminated during molding of the propeller 100. The cores are stacked, and the prepreg web 120 is inserted into the sheet-shaped foam core 140 during the molding process in the mold.

In addition, due to the variability due to the cross section of the airfoil of the propeller 100, the thickness of the foam core 140 is preferably 0.1 to 7 mm, and can be formed by compressing a foam sheet with a constant thickness.

In addition, the foam core 140 is provided with a slot 142 formed in the longitudinal direction so that the prepreg web 120 can be formed. The prepreg web 120 may be formed in the longitudinal direction by penetrating the foam core 140 in a direction perpendicular to the ground through the slot 142 of the foam core 140. At this time, it is preferable that the number of slots 142 formed in the foam core 140 is two or less.

The foam core 140 or the foam sheet forming the foam core 140 is made of one or more selected from polyvinyl chloride (PVC), polyethylene tereplate (PET), polypropylene (PP), and polymethacrylimide (PMI). It is desirable to include it.

When dividing the fiber-reinforced composite material propeller for drones into the longitudinal direction (X-axis), the width direction (Y-axis), and the direction perpendicular to the ground (Z-axis), the prepreg web 120 is located inside the foam core 140. It is located across the longitudinal direction (Z-axis), and during the propeller manufacturing process, the prepreg located between the first prepreg layer 110 and the foam core 140 is inserted into the slot 142 of the foam core 140. is formed.

The first prepreg layer 110 and the prepreg web 120 include carbon fibers arranged in one direction, and the carbon fibers are angled from 0 to 45 degrees in the direction perpendicular to the ground (Z axis) in the longitudinal direction of the propeller (X axis). It is desirable to have one of the arrangement angles. In addition, the first prepreg layer 110 and the prepreg web 120 prevent the propeller 100 from bending in the longitudinal direction, so it is recommended to use a unidirectional prepreg that can exhibit higher rigidity at the same weight per unit area. desirable. At this time, the first prepreg layer 110 and the prepreg web 120 may be formed of one prepreg, or may be formed by laminating two or more prepregs.

The second prepreg layer 130 is exposed to the surface of the propeller 100 and serves to prevent the propeller 100 from being twisted from the load generated by the rotation of the propeller 100. To this end, the second prepreg layer 130 includes two or more carbon fibers arranged in both directions, and preferably has an angle of -45 degrees/+45 degrees between the carbon fibers arranged in both directions. If it is outside the above range, the orientation direction of the fiber becomes closer to the longitudinal direction, which is advantageous for reinforcing bending strength and rigidity, but there may be a problem of lowering torsional strength and rigidity.

The second prepreg layer 130 has an angle of -45 degrees/+45 degrees rather than the same direction as the first prepreg layer 110, so that the first prepreg layer 110 and the second prepreg layer 130 have an angle of -45 degrees/+45 degrees. The directions of the fibers of the prepreg layer 130 are crossed, which serves to prevent deformation due to external force applied to the propeller 100. At this time, the second prepreg layer 130 can be formed by using a single prepreg or by stacking two or more prepregs. At this time, the second prepreg layer 130 may be either a unidirectional prepreg or a fabric prepreg, but in the case of unidirectional prepreg, cross-lamination must be performed, and in this case, the symmetry of the lamination must be considered, so the number of laminations inevitably increases. This may cause an increase in the overall weight of the propeller 100 and a decrease in workability. Therefore, considering weight and workability, it is preferable to use fabric prepreg for the second prepreg layer 130.

The thickness of the first prepreg layer 110 is preferably 0.3 to 0.7 mm, and the thickness of the second prepreg layer 130 is preferably 0.1 to 0.3 mm. As the size of the propeller 100 increases, the required thrust increases, so the number of prepreg stacks increases. In general, the size of the propeller 100 using a fiber-reinforced composite material is 10 inches or more, and it is necessary to achieve the above thickness in order to satisfy the thrust required for the propeller 100 with a size of 10 inches or more. If the above thickness is not achieved, sufficient bending and twisting characteristics to achieve the required thrust are not developed. On the other hand, if the thickness is too thick, the weight increases and lightweighting cannot be achieved. In particular, due to the nature of the elongated shape of the propeller 100, deformation occurs more severely due to bending than torsion, so reinforcement in the longitudinal direction of the propeller 100 is more important. Therefore, it is desirable to reinforce the first prepreg layer 110 to be thicker than the second prepreg layer 130.

The prepreg web 120 has a length in which the prepreg layered between the first prepreg layer 110 and the foam core 140 penetrates and is inserted into the slot 142 formed in the foam core 140 in a direction perpendicular to the ground. formed in a direction. At this time, the prepreg web 120 has a structure in which the upper and lower parts are continuously connected to the first prepreg layer 110.

And it is preferable that the number of prepreg webs 120 is two or less. At this time, if the number of prepreg webs 120 exceeds two, the rigidity can be increased, but the weight becomes heavy, making it impossible to achieve lightweighting, which has the problem of deteriorating overall performance.

Additionally, the width (w) of the prepreg web 120 is preferably 1 to 3 mm. At this time, if the width (w) of the prepreg web 120 is less than 1 mm, the effect of reinforcing rigidity is insignificant, and if it is more than 3 mm, the lightweight effect is reduced and the overall performance of the propeller is reduced.

The first prepreg layer 110, prepreg web 120, and second prepreg layer 130 are formed of prepreg containing carbon fiber and polymer resin (matrix resin). The polymer resin preferably contains at least one selected from thermosetting resins such as epoxy, vinyl ester, and unsaturated polyester resin, and it is more preferable to use epoxy resin.

In addition, since the weight of the propeller is a very important influencing factor in the performance of the propeller 100, in order to reduce it, it is desirable to use carbon fiber with high specific strength and specific stiffness in the prepreg.

The first prepreg layer 110, prepreg web 120, and second prepreg layer 130 may further include functional materials as a way to strengthen toughness for shock absorption. The functional material is a thermoplastic resin particle with high toughness and can be used by adding it to the matrix resin. Thermoplastic resin particles include polyacryl, polyester, polyvinyl, polyurethane, polyether, polyamide, polyimide, and polyether amide ( polyether amide), polyketone, polyether ketone, polyetheretherketone, polysulfone, polyethersulfone, polyetherethersulfone, polyphenylsulfone Any one or more selected from the group of polyphenylsulfone and polyphenylene oxide can be used.

As shown in FIG. 3, in order to form the prepreg web 120, a slot 142 is formed in the foam core 140 in the longitudinal direction of the propeller as long as the prepreg web 120, and the formed slot ( The prepreg forming the prepreg web 120 positioned corresponding to 142) penetrates into the slot 142 of the foam core 140 by the heat and pressure applied to the mold during molding to form the prepreg web 120. do. By forming such a prepreg web 120, bending rigidity can be increased compared to a typical conventional propeller, and weight reduction is possible compared to a propeller having the same bending rigidity.

It is preferable that the flexural strength of the fiber-reinforced composite propeller for drones according to an embodiment of the present invention is 230 to 400 MPa.

And it is preferable that the bending rigidity of the fiber-reinforced composite propeller for drones according to an embodiment of the present invention is 40 to 60 GPa.

In addition, the weight of the fiber-reinforced composite material propeller for drones according to an embodiment of the present invention is preferably 26 to 35 g, and the length is 16 to 18 inches.

Figure 4 is a cross-sectional view in the width direction of a fiber-reinforced composite propeller for drones according to another embodiment of the present invention.

Referring to FIG. 4, two prepreg webs 120 can be formed instead of just one as shown in FIG. 1. By creating two slots inside the foam core 140 to form two prepreg webs 120, the bending rigidity of the propeller 100 can be further increased.

Figure 5 is a diagram for explaining a method of manufacturing a fiber-reinforced composite propeller according to an embodiment of the present invention, and Figure 6 is a flow chart showing a method of manufacturing a fiber-reinforced composite propeller according to an embodiment of the present invention.

Referring to Figures 5 and 6, the method of manufacturing a fiber-reinforced composite propeller according to an embodiment of the present invention includes the step of performing release treatment on the inside of the upper and lower propeller molds (S601), a first prepreg layer, and a second Cutting the prepreg of the prepreg layer and the prepreg web (S602), forming a slot into which the prepreg web is inserted into the foam core (S603), cutting the second prepreg layer and the first prepreg layer. Sequentially stacking the upper and lower molds (S604), locally arranging the prepreg web on the stacked first prepreg layer to correspond to the slot position (S605), the first prepreg layer and the prepreg web Laminating the foam core on top (S606), joining the upper mold and the lower mold (S607), mounting the joined mold on the press, heating and pressurizing (S608), and demolding and trimming the molded propeller. It may include a step (S609).

First, in the step of performing release treatment on the inside of the upper and lower propeller molds (S601), a release agent is applied to the inner surfaces of the upper and lower propeller molds 300 and 310. At this time, it is preferable to use a liquid mold release agent rather than a solid phase so that the propeller mold surface can be made uniform and smooth. Additionally, it is desirable to finish the surface on which the release agent is applied by wiping it with a woven material such as silk. If the release agent is not applied evenly and smoothly to the surface, stains of the release agent remain on the mold surface, which may be transferred to surface stains on the molded product after molding. Adhesion to the mold surface during prepreg lamination is reduced due to the excessive release agent remaining on the mold surface. This may fall.

Next, the step of cutting the prepregs of the first prepreg layer, the second prepreg layer, and the prepreg web (S602) is to cut the prepregs forming the first prepreg layer 110 and the prepreg web 120. It may include the step of cutting in the direction of arrangement of the fibers and the step of cutting the prepreg forming the second prepreg layer 130 at an angle of -45 degrees/+45 degrees with respect to the direction of arrangement of the fibers.

Next, in the step of forming a slot into which the prepreg web is inserted into the foam core (S603), a slot 142 is formed in the foam core 140 in the longitudinal direction of the propeller. The slots 142 formed in the foam core 140 are formed so that the prepreg web 120 can be formed in the longitudinal direction by penetrating the foam core in a direction perpendicular to the ground, and one or two slots may be formed. In addition, in the present invention, the foam core 140 is formed using a sheet-shaped foam material (foam sheet) so that the prepreg web 120 can be formed by penetrating the foam core 140.

Next, the step (S604) of sequentially stacking the cut second prepreg layer and the first prepreg layer on the upper and lower molds is equally applied to both the lower mold 310 and the upper mold 300. The second prepreg layer 130 and the first prepreg layer 110 are sequentially stacked on the surfaces of the molds 300 and 310.

Next, the step of locally arranging the prepreg web on the laminated first prepreg layer to correspond to the slot position (S605) is to place the prepreg web 120 on the first prepreg layer 110 with a foam core ( It is positioned to correspond to the slot 142 formed in 140). At this time, the prepreg forming the prepreg web 120 is not located over the entire surface of the first prepreg layer 110, but is positioned in the slot 142 so that it can be inserted into the slot 142 of the foam core 140. It is located locally only at the location corresponding to .

In steps S604 and S605 described above, it is preferable to stack the prepregs so that no bubbles remain at the interface between the laminated prepregs and the prepreg-mold surface. In particular, air bubbles remaining at the interface between the prepreg and the mold surface can cause poor appearance, so air bubble removal is more important.

Next, the step of laminating the foam core on the first prepreg layer and the prepreg web (S606) is performed on the first prepreg layer 110 and the prepreg web 120 of the lower mold 310 laminated through step S605. ) Laminate the cut sheet-shaped foam core 140 on top. At this time, the position of the prepreg web 120 and the position of the slot 142 created in the sheet-shaped foam core 140 are arranged to match.

More specifically, in steps S605 and S606 described above, prepreg forming the second prepreg layer 130 is stacked in the upper mold 300 and the lower mold 310. Then, unidirectional prepreg is laminated in the longitudinal direction of the propeller forming the first prepreg layer 110 on the prepreg forming the second prepreg layer 130, and then the prepreg web 120 is formed. Unidirectional prepregs are stacked in the longitudinal direction of the propeller to form the prepreg web 120 at the position. Next, the sheet-shaped foam core 140 is stacked on the first prepreg layer 110 and the prepreg web 12 laminated on the lower mold 310, and through the subsequent process, the upper mold 300 is placed on the lower mold 310. They are placed on the mold 310, joined together, and molded in a press.

Next, in the step of engaging the upper mold and the lower mold (S607), the upper mold 300 and the lower mold 310 are engaged. At this time, when covering the upper mold 300 with the lower mold 310, it is desirable to prevent the prepreg laminated inside the mold from being pushed or falling off the mold surface. To achieve this, it is desirable to apply guide pins or guide plates for positioning the upper and lower molds to the propeller mold itself.

Next, before performing step S608, which will be described later, a step of preheating the joined mold at a temperature of 80 to 100° C. may be further performed. This is to improve flowability by lowering the viscosity of the polymer resin (matrix resin) impregnated in the prepreg. Through this preheating process, the appearance of the propeller can be improved and performance can be improved. At this time, if the preheating temperature is less than 80℃, the effect of lowering the viscosity of the polymer resin (matrix resin) is low and the resin flowability is not improved. If the preheating temperature is above 100℃, the flowability of the polymer resin (matrix resin) is maximized, but curing progresses and appearance problems occur. can cause

Next, the step of heating and pressurizing the joined mold after mounting it on the press (S608) is performed on the first prepreg layer 110, prepreg web 120, and second prepreg layer 130 placed inside the mold. By applying a predetermined temperature and pressure through a press, the prepreg web 120 penetrates or flows into the slot 142 of the foam core 140 by heat and pressure, penetrating the foam core 140 and forming a prepreg web ( 120) is formed.

At this time, the temperature applied to the mold (press temperature) is preferably 120 to 150°C, and the pressing time is preferably 0.5 to 5 hours. If the pressing temperature is less than 120°C, problems with molding defects and deterioration of physical properties occur due to non-curing of the first prepreg layer 110, prepreg web 120, and second prepreg layer 130, and the pressing temperature is 150°C. If the temperature exceeds ℃, the problem of resin deterioration due to excessive temperature occurs in the foam core 140, first prepreg layer 110, and prepreg web 120 inside the propeller mold.

In addition, it is preferable that the pressing pressure applied to the mold (pressing pressure of the press) is 0.1 to 10 MPa. If the pressure is less than 0.1 MPa, the prepreg placed inside the mold is not sufficiently pressurized due to the low pressure, leading to problems such as non-impregnation of the surface or deterioration of the interlayer adhesion between the first prepreg layer 110 and the prepreg web 120. If the pressure exceeds 10 MPa, the mold may be deformed due to excessive pressure or the cross-sectional shape of the propeller may change as a result.

In addition, in the step of heating and pressurizing the joined mold after mounting it on the press (S608), it is preferable to perform two or more multi-stage pressing processes in the process of pressing through the press.

Next, the step of demolding and trimming the molded propeller (S609) is preferably performed after the molds 300 and 310 are cooled below the glass transition temperature of the matrix resin. When demolding above the glass transition temperature, the cross-section of the propeller swells due to the compression repulsion force of the foam core 140, which may cause performance to deteriorate. In addition, the trimming step is a process of removing burrs of resin or carbon fiber protruding outside the propeller shape and drilling holes for mounting on the motor, and is preferably performed through machining. In addition, it is desirable to position the hole in an accurate position so that it is not biased to the left, right, front, or back.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims are also possible. falls within the scope of rights.

100: Fiber-reinforced composite material propeller for drones
110: first prepreg layer
120: prepreg web
130: Second prepreg layer
140: Foam core
142: slot
300: upper mold
310: lower mold

Claims (16)

Foam core with slots formed in the longitudinal direction;
A first prepreg layer surrounding the outer surface of the foam core;
A prepreg web is formed in the longitudinal direction by penetrating the foam core in a direction perpendicular to the ground through a slot of the foam core, and the upper and lower portions are continuously connected to the first prepreg layer; and
a second prepreg layer surrounding the outer surface of the first prepreg layer;
A fiber-reinforced composite material propeller for drones, including. According to paragraph 1,
The first prepreg layer and the prepreg web include carbon fibers arranged in one direction, and the carbon fibers arranged in one direction have an arrangement angle of any one of 0 to 45 degrees in the direction perpendicular to the ground in the longitudinal direction of the propeller. A fiber-reinforced composite material propeller for drones. According to paragraph 1,
The second prepreg layer includes carbon fibers arranged in both directions, and has an angle of -45 degrees / +45 degrees between the carbon fibers arranged in both directions. A fiber-reinforced composite propeller for drones. According to paragraph 1,
A fiber-reinforced composite material propeller for drones, wherein the foam core has a thickness of 0.1 to 7 mm. According to paragraph 1,
The thickness of the first prepreg layer is 0.3 to 0.7 mm,
A fiber-reinforced composite propeller for drones, wherein the thickness of the second prepreg layer is 0.1 to 0.3 mm. According to paragraph 1,
A fiber-reinforced composite propeller for drones, wherein the prepreg web has a width of 1 to 3 mm. According to paragraph 1,
A fiber-reinforced composite material propeller for drones, wherein the prepreg web is formed of two or less. According to paragraph 1,
The fiber-reinforced composite material propeller for drones has a flexural strength of 230 to 400 MPa. According to paragraph 1,
The fiber-reinforced composite material propeller for drones has a bending rigidity of 40 to 60 GPa. According to paragraph 1,
The weight of the fiber-reinforced composite material propeller for drones is 26 to 35 g, and the length is 16 to 18 inches. According to paragraph 1,
The foam core is a fiber-reinforced composite propeller for drones having two or less slots. In the method of manufacturing a fiber-reinforced composite propeller for drones according to claim 1,
Performing mold release treatment on the inside of the upper and lower propeller molds;
Cutting the prepreg of the first prepreg layer, the second prepreg layer, and the prepreg web;
Forming a slot into which the prepreg web is inserted into the foam core;
sequentially stacking the cut second prepreg layer and first prepreg layer on the upper and lower molds;
Locally disposing a prepreg web on the laminated first prepreg layer to correspond to the slot position;
Laminating a foam core on the first prepreg layer and the prepreg web;
joining the upper mold and the lower mold;
Mounting the joined mold on a press and then heating and pressurizing it; and
Demolding and trimming the molded propeller;
Method for manufacturing a fiber-reinforced composite material propeller for drones, including. According to clause 12,
A method of manufacturing a fiber-reinforced composite propeller for drones, wherein the heating temperature in the heating and pressurizing step is 120 to 150°C. According to clause 12,
A method of manufacturing a fiber-reinforced composite propeller for drones, wherein the pressing pressure in the heating and pressurizing step is 0.1 to 10 MPa. According to clause 12,
It is performed before the heating and pressurizing steps. Preheating the joined mold at a temperature of 80 to 100°C;
A method of manufacturing a fiber-reinforced composite propeller for drones, further comprising: According to clause 12,
A method of manufacturing a fiber-reinforced composite material propeller for drones, wherein the heating and pressurizing steps are performed through two or more multi-stage pressing processes.