NCF composite fiber sheet and method for manufacturing wheel rim using same

Abstract

The present invention relates to an NCF composite fiber sheet and a method for manufacturing a wheel rim using same, wherein the sheet can, during the manufacture of a vehicle wheel rim using composite fibers, prevent the slipping of the composite fibers wound around a rounded portion of a mold and facilitate axial fiber arrangement.

Description

NCF composite fiber sheet and method for manufacturing wheel rim using the same

[0001] The present invention relates to an NCF composite fiber sheet capable of preventing slippage of composite fibers wrapped around a round portion of a mold when manufacturing a vehicle wheel rim using composite fibers, and a method for manufacturing a wheel rim using the same.

[0002]

[0003] Typically, vehicle rims are manufactured primarily from materials such as iron or aluminum. These rims form the wheel to which the tire is attached. They are hollow and, depending on the material, can directly affect the vehicle's weight.

[0004] In vehicles currently under development, weight reduction can be a key factor in improving energy efficiency, or fuel economy. Therefore, the need for lightweight vehicle rims that maintain the same strength as existing rims is growing.

[0005] Accordingly, vehicle wheels featuring composite fiber rims are being developed. Compared to steel or aluminum rims, composite fiber rims are significantly lighter and offer similar or even improved strength.

[0006] Referring to Figure 1, composite fiber sheets manufactured using composite fibers can be divided into fabric fiber sheets and NCF (Non Crimped Fabric) fiber sheets.

[0007] Specifically, the fabric fiber sheet is manufactured in a woven form by interweaving composite fibers in a bendable manner (see (a) of Fig. 1).

[0008] And the above NCF composite fiber sheet is manufactured by arranging composite fibers in multiple angle layers and then fixing them without weaving them to prevent bending of composite fibers and to facilitate application of various fiber directions (see (b) of Fig. 1).

[0009] In this case, the fabric fiber sheet may allow some deformation depending on the weaving density, but the range is limited.

[0010] In addition, the NCF composite fiber sheet also uses fixed threads to maintain fiber layers arranged at various angles, so deformation into various shapes is limited.

[0011] Meanwhile, a rim manufactured using the above composite fiber material can be manufactured through a method such as winding or braiding.

[0012] However, the rim manufacturing method using the above winding method causes the composite fibers to move along the geodetic path due to the tension applied during winding, and may cause the composite fibers to slip along the inclined surface (R) of the mold (see Fig. 2). Accordingly, winding may not be easy in certain areas of the mold, making it difficult to arrange the fibers along the axial direction of the mold.

[0013] The above-described method of manufacturing a rim using braiding allows for the composite fibers to be densely arranged in a small-diameter area by sliding along an inclined surface (R) (see Fig. 3) in a section where the diameter of the mold changes. In this case, it can be difficult to control the braiding angle and arrange the composite fibers along the axial direction of the mold.

[0014]

[0015] The present invention is intended to solve the above-described problems, and the purpose of the present invention is to provide an NCF composite fiber sheet that can prevent slippage of composite fibers wrapped around a round part of a mold and facilitate axial fiber arrangement when manufacturing a vehicle wheel rim using composite fibers, and a method for manufacturing a wheel rim using the same.

[0016]

[0017] In order to achieve the above-described purpose, the NCF composite fiber sheet according to the present invention may include a first NCF composite fiber sheet in which composite fibers are arranged at a predetermined angle with respect to a first direction and are continuously arranged along the first direction; a second NCF composite fiber sheet in which a plurality of strands of composite fibers are arranged on an upper surface of the first NCF composite fiber sheet in a direction intersecting with the composite fibers and are continuously arranged and laminated along the first direction; and an elastic thread stitched along the first direction of the laminated first and second NCF composite fiber sheets to impart elasticity to the first and second NCF composite fiber sheets so that they can be stretched along the first direction.

[0018] In this case, the composite fibers of the first NCF composite fiber sheet may be arranged at an angle of 30 to 60° with respect to the first direction, and the composite fibers of the second NCF composite fiber sheet may be arranged at an angle of -30 to -60° with respect to the first direction.

[0019] In addition, the elastic thread may include a plurality of strands spaced apart at a predetermined interval in a direction intersecting the first direction.

[0020] In addition, the lower surface of the first NCF composite fiber sheet or the upper surface of the second NCF composite fiber sheet may further include a third NCF composite fiber sheet laminated in which composite fibers are arranged in a direction perpendicular to the first direction and are continuously arranged along the first direction.

[0021] In addition, the elastic thread may include a thermoplastic elastomer (TPE) that is melted at a predetermined temperature and can be formed into a preform having a curve without a separate binder when pressed.

[0022] Additionally, the elastic thread may include a material formed of a material having a melting point set to be meltable at the resin injection temperature of the RTM (Resin Transfer Molding) process.

[0023] Additionally, the NCF composite fiber sheet may include one formed in a hollow cylindrical shape.

[0024] In addition, the elastic room may include a ring-shaped arrangement along the outer circumference based on the central axis of the cylinder.

[0025]

[0026] Meanwhile, a method for manufacturing a vehicle wheel rim using the NCF composite fiber sheet may include a step of applying a binder to the NCF composite fiber sheet; a step of winding the NCF composite fiber sheet to which the binder has been applied around the outer circumference of a mold and then pressing it with a press to form a preform having a curve; and a step of injecting a resin into the formed preform through an RTM (Resin Transfer Molding) process to manufacture a finished product.

[0027] In this case, the method may further include a step of winding and laminating another composite fiber on the outer surface of the NCF composite fiber sheet wound around the mold through a winding process.

[0028]

[0029] Meanwhile, a method for manufacturing a vehicle wheel rim using an NCF composite fiber sheet according to another embodiment may include: a step of applying a binder to the NCF composite fiber sheet; a step of wrapping the NCF composite fiber sheet to which the binder has been applied around the outer circumference of a mold, and then fixing the NCF composite fiber sheet by stitching while the two ends are in contact with each other; a step of forming a preform having a curve by compressing the NCF composite fiber sheet by a press; and a step of injecting a resin into the formed preform through an RTM (Resin Transfer Molding) process to manufacture a finished product.

[0030] In this case, in order to improve the circumferential strength of the vehicle wheel rim and to implement a shape in which the wheel rim thickness changes depending on the axial position, a step of winding and laminating another composite fiber on the outer surface of the NCF composite fiber sheet wound around the mold may be further included.

[0031]

[0032] The NCF composite fiber sheet according to the present invention having the above-described configuration and the method for manufacturing a wheel rim using the same can manufacture an NCF composite fiber sheet by laminating a first NCF composite fiber sheet and a second NCF composite fiber sheet in a direction intersecting at a predetermined angle, and stitching an elastic thread along one direction of the laminated first NCF composite fiber sheet and the second NCF composite fiber sheet to impart elasticity so that the NCF composite fiber sheet can be stretched in one direction.

[0033] That is, by imparting elasticity to the existing NCF composite fiber sheet, when manufacturing a cylindrical structure with a complex shape such as a vehicle wheel, the NCF composite fiber sheet with an axial direction or an arbitrary angle can be easily deformed and fixed according to the bend.

[0034] In addition, by manufacturing the NCF composite fiber sheet in a cylindrical shape and winding it around the outer surface of the mold, it is possible to manufacture a preform in which composite fibers are evenly spaced over the entire outer surface, including the rounded slope of the mold.

[0035] Additionally, the elastic thread may be made of a thermoplastic elastomer (TPE) that can be melted at a predetermined temperature and formed into a preform with a curve without a separate binder when pressed with a press.

[0036] Accordingly, the process of applying a separate binder during the process of forming a preform can be omitted, thereby simplifying the process and improving production efficiency.

[0037] In addition, the elastic thread is composed of a material having a melting point set to melt at the resin injection temperature of the RTM (Resin Transfer Molding) process, thereby ensuring excellent bonding strength with the RTM resin. Accordingly, the structural strength of the wheel rim, which is a molded body, can be improved.

[0038]

[0039] Figures 1 (a) and (b) are photographs showing the types of composite fiber sheets.

[0040] Figure 2 is a photograph showing a preform manufactured by a conventional winding method.

[0041] Figure 3 is a photograph showing a preform manufactured by a conventional braiding method.

[0042] Figure 4 is a plan view showing an NCF composite fiber sheet according to the present invention;

[0043] Figure 5 is an actual photograph of the NCF composite fiber sheet according to the present invention.

[0044] Figures 6 (a) and (b) are photographs showing that the NCF composite fiber sheet according to the present invention is stretched to both sides by the elasticity of the elastic thread.

[0045] Figure 7 is a perspective view showing a cylindrical NCF composite fiber sheet according to the present invention.

[0046] Figure 8 is a perspective view of a preform manufactured using an NCF composite fiber sheet according to the present invention.

[0047] FIG. 9 is a perspective view of a wheel rim manufactured using an NCF composite fiber sheet according to the present invention.

[0048]

[0049] ※Explanation of symbols※

[0050] 1: Mold P: Preform

[0051] 10: Wheel rim 11: Spoke

[0052] 100: NCF composite fiber sheet X: 1st direction

[0053] 110: 1st NCF composite fiber sheet 120: 2nd NCF composite fiber sheet

[0054] 130: Elastic room

[0055]

[0056] The configuration and operation of a specific embodiment of the present invention will be described in detail with reference to the attached drawings.

[0057] Here, when adding reference signs to components of each drawing, it should be noted that identical components are indicated with the same signs as much as possible even if they are shown in different drawings.

[0058] Fig. 4 is a plan view showing an NCF composite fiber sheet according to the present invention, and Fig. 5 is an actual photograph showing an NCF composite fiber sheet according to the present invention.

[0059] Referring to FIGS. 4 and 5, an NCF composite fiber sheet (100) for manufacturing a vehicle wheel rim according to a preferred embodiment of the present invention may include a first NCF composite fiber sheet (110), a second NCF composite fiber sheet (120), and an elastic thread (130).

[0060] The composition of the present invention is described in detail as follows.

[0061]

[0062] First, the first NCF composite fiber sheet (110) can be formed in such a manner that composite fibers are arranged at a predetermined angle with respect to an arbitrary first direction (X) (see FIG. 3), and multiple strands of the composite fibers are continuously arranged along the first direction (X).

[0063] In this case, the first NCF composite fiber sheet (110) may have composite fibers arranged in a continuous and dense manner along the first direction (X), or arranged at a predetermined interval along the first direction (X). In the present invention, an example in which the first NCF composite fibers are arranged in a continuous and dense manner along the first direction (X) will be illustrated and described. Of course, the present invention is not limited thereto.

[0064] For reference, the first direction (X) above is a direction intersecting the central axis of a mold (1) (see FIG. 7) for forming a vehicle wheel rim (10), and may also mean a direction in which an elastic thread (130) described later is stitched.

[0065]

[0066] The above second NCF composite fiber sheet (120) may be arranged on the upper surface of the first NCF composite fiber sheet (110) in a direction intersecting with the composite fibers of the first NCF composite fiber sheet (110), and may be configured in such a way that multiple strands of composite fibers are continuously arranged and laminated along the first direction (X).

[0067] In this case, an example in which the composite fibers of the second NCF composite fiber sheet (120) are densely arranged in a row along the first direction (X) to correspond to the composite fibers of the first NCF composite fiber sheet (110) will be illustrated and described.

[0068] Specifically, referring to FIG. 4, the composite fibers of the first NCF composite fiber sheet (110) may be arranged at an angle of 30 to 60°, preferably 45°, with respect to the first direction (X). And the composite fibers of the second NCF composite fiber sheet (120) may be arranged at an angle of -30 to -60°, preferably -45°, with respect to the first direction (X).

[0069] That is, if the multiple strands of composite fibers constituting the first and second NCF composite fiber sheets (110, 120) are outside the range of 30 to 60° and -30 to -60°, respectively, the stitching process using the elastic yarn (130) described later may not be smooth.

[0070] In this case, the composite fiber applied to the first and second NCF composite fiber sheets (110)(120) may be a long fiber such as glass fiber or carbon fiber, but the present invention does not specifically limit it.

[0071]

[0072] The above elastic room (130) can provide elasticity so that the laminated first and second NCF composite fiber sheets (110)(120) can stretch along the first direction (X).

[0073] Specifically, the elastic thread (130) can be applied in a stitching manner along the first direction (X) of the laminated first and second NCF composite fiber sheets (110)(120). Since the stitching process for fixing the laminated first and second NCF composite fiber sheets (110)(120) is a previously known technology, a detailed description thereof will be omitted.

[0074] In this case, the elastic thread (130) may be arranged in a plurality of strands spaced apart in parallel in a direction (Y) intersecting the first direction (X) to correspond to the area where the first and second NCF composite fiber sheets (110) (120) are laminated.

[0075] Referring to (a) and (b) of FIG. 6, the first and second NCF composite fiber sheets (110) (120) formed in the form of an NCF composite fiber sheet (100) by stitching using the elastic thread (130) as a medium are stretched to a predetermined length when pulled in both directions (see (b) of FIG. 6) in the first direction (X) due to the elasticity of the elastic thread (130).

[0076] In contrast, when the NCF composite fiber sheet (100) is pulled in an up-down direction intersecting the first direction (X), the NCF composite fiber sheet (100) does not stretch at all.

[0077] That is, the elastic thread (130) can provide elasticity only in the first direction (X). Accordingly, the direction intersecting the first direction (X) can be maintained in a fixed state by intertwining the first and second NCF composite fiber sheets (110) (120) with each other through the structure of the elastic thread (130) stitched in the first direction (X).

[0078] Referring to Fig. 7, the NCF composite fiber sheet (100) stitched via the elastic thread (130) may be formed into a hollow cylindrical shape. In this case, the elastic thread (130) may be arranged in a ring shape along the outer circumference based on the central axis of the cylinder.

[0079] Accordingly, the cylindrical NCF composite fiber sheet (100) can be wound around the outer surface of the mold (1) along the axial direction through a process of covering it, and as shown in FIG. 8, it is possible to manufacture a preform (P) in which composite fibers are arranged at uniform intervals over the entire outer surface including the rounded inclined surface (R) of the mold (1).

[0080]

[0081] In another embodiment, the elastic chamber (130) may be made of a thermoplastic elastomer (TPE) that can be melted at a predetermined temperature and formed into a preform having a curve without a separate binder when pressed with a press.

[0082] Accordingly, the process of separately applying a binder during the process of forming a preform can be omitted.

[0083] In addition, the elastic thread is composed of a material having a melting point set to melt at the resin injection temperature of the RTM (Resin Transfer Molding) process, thereby ensuring excellent bonding strength with the RTM resin. Accordingly, the structural strength of the wheel rim (10) can be improved.

[0084]

[0085] Then, the process of manufacturing a wheel rim using the NCF composite fiber sheet (100) according to the present invention having the above-described configuration will be described.

[0086] <First Embodiment>

[0087] First, a NCF composite fiber sheet (100) (see FIG. 7) is manufactured by stacking and arranging multiple strands of composite fibers constituting the first and second NCF composite fiber sheets (110) (120) respectively at a predetermined angle tilted relative to the first direction (X) and stitching an elastic thread (130) along the first direction (X), and then a binder is applied to the manufactured NCF composite fiber sheet (100). In this case, the NCF composite fiber sheet (100) can be manufactured in a cylindrical shape.

[0088] The NCF composite fiber sheet (100) to which the above binder is applied is wrapped around the outer surface of a mold (1) and then pressed with a press to form a preform (P) with a curve (see Fig. 8).

[0089] Afterwards, by injecting resin into the formed preform (P) through the RTM (Resin Transfer Molding) process, the manufacturing of the wheel rim (10) is completed (see Fig. 9). Since the RTM process is a well-known technology, a detailed description thereof will be omitted.

[0090] In this case, if the elastic room (130) is formed of a thermoplastic elastomer (TPE) that can melt at a predetermined temperature, a separate binder application process can be omitted.

[0091] In addition, since the elastic thread (130) is composed of a material having a melting point set to be meltable at the resin injection temperature of the RTM (Resin Transfer Molding) process, excellent bonding strength with the RTM resin can be secured. Accordingly, the structural strength of the wheel rim (10) can be improved.

[0092] And, by integrally joining a spoke (11) (see Fig. 8) manufactured through a separate process to one side opening of the wheel rim (10), a vehicle wheel structure can be completed.

[0093]

[0094] <Second Embodiment>

[0095] In another embodiment, a third NCF composite fiber sheet (not shown) may be further laminated on the bottom surface of the first NCF composite fiber sheet (110) or the top surface of the second NCF composite fiber sheet (120) in the first embodiment, in which composite fibers are arranged in a direction perpendicular to the first direction (X) and are continuously arranged along the first direction (X).

[0096] In this case, even if the third NCF composite fiber sheet is further laminated, the elasticity in the first direction (X) by the elastic room (130) can be maintained as is.

[0097]

[0098] <Third Embodiment>

[0099] In another embodiment, the NCF composite fiber sheet (100) can be applied by changing the stitching and laminating methods of the first and second NCF composite fiber sheets (110) (120) in a different manner.

[0100] Specifically, first, multiple strands of composite fibers are arranged along a first direction (X), and then elastic threads (130) are stitched along the first direction (X) to form a first NCF composite fiber sheet (110).

[0101] Then, a plurality of strands of composite fibers are arranged along the first direction (X) in a direction intersecting with the composite fibers of the first NCF composite fiber sheet (110), and then an elastic thread (130) is stitched along the first direction (X) to form a second NCF composite fiber sheet (120).

[0102] After that, a NCF composite fiber sheet (100) is formed by laminating a second NCF composite fiber sheet (120) on the upper surface of the first NCF composite fiber sheet (110). Then, a binder is applied to the formed NCF composite fiber sheet (100).

[0103] The NCF composite fiber sheet (100) to which the above binder is applied is wrapped around the outer surface of a mold (1) and then pressed with a press to form a preform (P) with a curve.

[0104] After that, by injecting resin into the formed preform (P) through the RTM (Resin Transfer Molding) process, the manufacturing of the wheel rim (10) is completed.

[0105] In this case, the present invention has been illustrated and described as an example in which a laminated structure of two sheets, such as the first and second NCF composite fiber sheets (110)(120), is applied, but of course, it is not limited thereto and may be changed and applied to a case in which a laminated structure of two or more sheets is applied. At this time, the composite fibers stitched via the elastic thread (130) may be arranged at different angles (90°, ±45°, etc.) with respect to the first direction (X) so as to be able to intersect.

[0106]

[0107] <Fourth Embodiment>

[0108] In another embodiment, the NCF composite fiber sheet (100) may be formed into a flat, expanded shape rather than a cylindrical shape as in the first embodiment.

[0109] In this case, a binder is applied to the NCF composite fiber sheet (100) developed above, and after the NCF composite fiber sheet (100) to which the binder is applied is wrapped around the outer surface of the mold (1), both ends of the NCF composite fiber sheet (100) are stitched together while facing each other and fixed.

[0110] After that, a finished product can be manufactured by sequentially performing the preform forming process by pressing as in the first embodiment and the process of injecting resin through the RTM process.

[0111]

[0112] <Example 5>

[0113] In another embodiment, in order to reinforce the structure of the NCF composite fiber sheet (100) wound around the mold (1) in the first to fourth embodiments, another composite fiber may be wound and laminated around the outer surface of the NCF composite fiber sheet (100) through a circumferential winding process. Accordingly, a fiber reinforcing effect can be expected in the direction of the outer surface of the mold (1), and the preform (P) can be formed into a more solid structure. The winding process may be selectively performed before or after the pressing process of the NCF composite fiber sheet (100).

[0114]

[0115] Although the present invention has been described and illustrated with specific embodiments above, the present invention is not limited to the above-described embodiments, and various changes and modifications are possible within a scope that does not depart from the technical spirit of the present invention.

Claims

1. A first NCF composite fiber sheet in which composite fibers are arranged in an arbitrary first direction and at a predetermined angle and are continuously arranged along the first direction; A second NCF composite fiber sheet having composite fibers arranged in a direction intersecting the composite fibers on the upper surface of the first NCF composite fiber sheet and continuously arranged along the first direction; and An NCF composite fiber sheet comprising an elastic thread stitched along the first direction of the laminated first and second NCF composite fiber sheets to provide elasticity to the first and second NCF composite fiber sheets so that they can be stretched along the first direction.

2. In paragraph 1, The composite fiber of the above first NCF composite fiber sheet is, It is arranged at an angle of 30 to 60° with respect to the first direction, The composite fiber of the above second NCF composite fiber sheet is, An NCF composite fiber sheet comprising a fiber arranged at an angle of -30 to -60° with respect to the first direction.

3. In paragraph 1, The above elastic room is, An NCF composite fiber sheet comprising a plurality of strands spaced apart at a predetermined interval in a direction intersecting the first direction.

4. In paragraph 1, An NCF composite fiber sheet further comprising a third NCF composite fiber sheet laminated on the lower surface of the first NCF composite fiber sheet or the upper surface of the second NCF composite fiber sheet, wherein composite fibers are arranged in a direction perpendicular to the first direction and are continuously arranged along the first direction.

5. In paragraph 1, The above elastic room is, An NCF composite fiber sheet comprising a thermoplastic elastomer (TPE) that can be melted at a predetermined temperature and formed into a preform having a curve when pressed.

6. In paragraph 5, An NCF composite fiber sheet including the elastic yarn formed of a material having a melting point set to be meltable at the resin injection temperature of an RTM (Resin Transfer Molding) process.

7. In paragraph 3, The above NCF composite fiber sheet, NCF composite fiber sheet including one formed into a hollow cylindrical shape.

8. In paragraph 7, The above elastic room is, An NCF composite fiber sheet comprising a ring-shaped arrangement along the outer circumference based on the central axis of the cylinder.

9. A method for manufacturing a vehicle wheel rim using any one of the NCF composite fiber sheets of clauses 1 to 8, A step of applying a binder to the above NCF composite fiber sheet; A step of forming a preform having a curve by wrapping the NCF composite fiber sheet coated with the above binder around the outer surface of a mold and then pressing it with a press; and A method for manufacturing a vehicle wheel rim, comprising: a step of manufacturing a finished product by injecting resin into the formed preform through an RTM (Resin Transfer Molding) process.

10. In paragraph 9, A method for manufacturing a wheel rim for a vehicle, further comprising a step of winding and laminating another composite fiber on the outer surface of the NCF composite fiber sheet wound around the mold through a winding process.

11. A method for manufacturing a vehicle wheel rim using any one of the NCF composite fiber sheets of clauses 1 to 6, A step of applying a binder to the above NCF composite fiber sheet; A step of wrapping the NCF composite fiber sheet to which the above binder has been applied around the outer surface of a mold and then fixing it by stitching while the two ends are aligned with each other; A step of forming a preform having a curve by pressing the NCF composite fiber sheet; and A method for manufacturing a vehicle wheel rim, comprising: a step of manufacturing a finished product by injecting resin into the formed preform through an RTM (Resin Transfer Molding) process.

12. In paragraph 11, A method for manufacturing a wheel rim for a vehicle, further comprising a step of winding and laminating another composite fiber on the outer surface of the NCF composite fiber sheet wound around the mold through a winding process.

Images