JP2011218757A - Fiber reinforced resin structure member, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber reinforced resin structure member capable of reducing weight, reducing a manufacturing cost, improving strength, also enabling mass production, inexpensive in a material and further capable of molding a complicated shape, and to provide a method for manufacturing the same.SOLUTION: In the fiber reinforced resin structure member 1 formed out of a composite material of a resin and fibers, an internal layer part 2 is composed of a core material in which a fiber structure is impregnated with a thermoplastic resin and an external layer part 3 covering the periphery of this internal layer part 2 is composed of a thermoplastic resin containing long fibers.

Description

  The present invention relates to a fiber-reinforced resin structural member reinforced with fibers and a method for producing the same.

  Conventionally, structural members such as the chassis of automobile powertrains have been manufactured by the aluminum die casting method, but further weight reduction and cost reduction are the challenges and requirements of the automobile industry. Manufacturing process transformation and weight reduction are near limits.

  Therefore, as described in Patent Document 1, a laminated structure made of a fiber reinforced resin has been proposed as a means for reducing weight and cost. Such a fiber reinforced resin injection-molded can be made lighter than aluminum die-casting, and can be manufactured at a lower cost without a post-process such as machining.

  However, in such a case, the weight is only about 30%, and it is difficult to say that the strength is sufficient in a case where a relatively large load such as an automobile part is applied.

  Accordingly, thermosetting carbon fiber reinforced plastics have been proposed as being capable of further reducing the weight and improving the strength.

JP 2007-307778 A

  However, such thermosetting carbon fiber reinforced plastics have problems that mass production is difficult, materials are expensive, and complicated shapes are difficult to mold.

  In view of the conventional technology, the present invention can reduce the weight, reduce the manufacturing cost, improve the strength, can be mass-produced, the material is inexpensive, and a complicated shape can be formed. An object of the present invention is to provide a fiber reinforced resin structural member and a method for producing the same.

  In order to solve this problem, the invention described in claim 1 is a fiber reinforced resin structural member made of a composite material of resin and fiber, wherein the inner layer portion is a core material in which a fibrous structure is impregnated with a thermoplastic resin. The outer layer part which comprises and covers the circumference | surroundings of this inner layer part was made into the fiber reinforced resin structural member which consists of a thermoplastic resin containing a long fiber.

  In addition to the structure of Claim 1, the invention according to Claim 2 is characterized in that the content ratio of the fiber to the thermoplastic resin is from the outer surface of the fiber reinforced resin structural member toward the center of the plate thickness. The fiber content is increased.

  The invention described in claim 3 is characterized in that, in addition to the structure described in claim 1 or 2, a metal or mineral powder is mixed in the thermoplastic resin of the outer layer portion.

  The invention described in claim 4 is characterized in that, in addition to the structure described in any one of claims 1 to 3, the fiber structure and the long fiber are carbon fibers.

  Invention of Claim 5 is a manufacturing method of the fiber reinforced resin structural member as described in any one of Claim 1 thru | or 4, Comprising: The said inner-layer part which is the said core material shape | molded in the predetermined shape previously The fiber-reinforced resin structural member is manufactured by injecting a thermoplastic resin containing the long fibers constituting the outer layer portion into the mold and molding the mold.

  The invention described in claim 6 includes, in addition to the configuration described in claim 5, a fixing means for fixing the inner layer portion to the mold when the inner layer portion is disposed in the mold. It is characterized by that.

  According to a seventh aspect of the invention, in addition to the configuration of the fifth or sixth aspect, the outer layer portion is injection-molded by at least a pair of discharge nozzles provided at substantially opposed positions of the fixed mold and the movable mold of the mold. It is characterized by being molded by injecting the molten thermoplastic resin containing the long fibers on both sides of the inner layer portion from the outlet.

  According to the first aspect of the present invention, the inner layer portion is composed of a core material in which a fiber structure is impregnated with a thermoplastic resin, and the outer layer portion is made of a thermoplastic resin containing long fibers. The cost can be reduced and the strength can be improved, mass production is possible, the material is inexpensive, and a complicated shape can be formed.

  According to the invention described in claim 2, since the content ratio of the fiber to the thermoplastic resin is increased from the outer surface of the fiber reinforced resin structural member toward the center of the plate thickness, Strength and rigidity can be improved.

  According to the invention described in claim 3, since the metal or mineral powder is mixed with the thermoplastic resin of the outer layer portion, the long fibers are not exposed on the surface, and the metal or mineral powder appears. By adjusting this metal or mineral powder, the color of the appearance can be adjusted.

  According to the invention described in claim 4, since carbon fibers are used for the inner layer portion and the outer layer portion, the strength can be effectively ensured with a lighter weight than other fibers.

  According to the invention described in claim 5, since the thermoplastic resin containing the long fibers constituting the outer layer portion is injected into the mold and molded around the inner layer portion, the fiber reinforced resin structural member can be easily formed. Can be molded.

  According to the invention described in claim 6, by providing the fixing means, the inner layer portion can be easily and stably disposed in the mold.

  According to the invention described in claim 7, the injection molding of the outer layer portion includes long fibers on both sides of the inner layer portion from at least a pair of discharge ports provided at substantially opposed positions of the fixed mold and the movable mold. Since the molten thermoplastic resin is injected, the molten resin can be easily spread all around the inner layer portion, and the wall thickness of the outer layer portion can be thinly and uniformly formed.

It is a perspective view which shows the gearbox for motor vehicles which is a fiber reinforced resin structural member which concerns on embodiment of this invention. It is sectional drawing of the fiber reinforced resin structural member which concerns on the same embodiment. It is a graph which shows the relationship between the plate thickness center direction in the cross section of the fiber reinforced resin structural member which is a molded article which concerns on the same embodiment, and the content rate of carbon fiber. It is a front view which shows the press die etc. which shape | mold the core material which concerns on the same embodiment. It is sectional drawing, such as a shaping | molding die which shows the shaping | molding state of the fiber reinforced resin structural member which concerns on the embodiment. It is sectional drawing of the state which released the shaping | molding die concerning the embodiment. It is a graph which shows the relationship between the fiber length which concerns on the same embodiment, and a fiber reinforcement effect coefficient. It is a graph which shows the relationship between the carbon fiber content rate and tensile strength which concern on the same embodiment.

  Embodiments of the present invention will be described below.

  1 to 8 are diagrams according to an embodiment of the present invention.

  A fiber reinforced resin structural member 1 according to this embodiment is an automotive gearbox as shown in FIG. 1 and is a resin structural member made of a composite material of resin and fiber, and as shown in FIG. It is comprised from the part 2 and the outer layer part 3 shape | molded so that the circumference | surroundings of this inner layer part 2 might be covered.

  The inner layer portion 2 is made of a core material in which a fiber structure is impregnated with a thermoplastic resin, and the outer layer portion 3 is made of a thermoplastic resin containing long fibers. As the thermoplastic resin of the inner layer portion 2 and the outer layer portion 3, for example, polypropylene (PP), polyamide (PA), polyphenylene sulfide (PPS), or the like is used. Here, the thermoplastic resin of the inner layer part 2 and the outer layer part 3 is formed of the same material in order to ensure adhesion, but not limited to this, any material can be used as long as it can ensure adhesion. good.

  The fiber structure and the long fiber are carbon fibers in this embodiment, but are not limited thereto, and may be fibers such as glass, stainless steel, and Kepler. The fiber structure may be a woven fabric, a non-woven fabric, or a mesh. Etc.

  Moreover, the content ratio of the carbon fiber to the thermoplastic resin is formed such that the carbon fiber content increases from the outer surface of the fiber reinforced resin structural member 1 toward the center of the plate thickness. That is, in FIG. 3, the relationship between the plate | board thickness center direction in the cross section of the fiber reinforced resin structural member 1 which is a molded article, and the content rate of carbon fiber is shown. According to this figure, the content of the carbon fiber on the surface of the outer layer portion 3 of the fiber reinforced resin structural member 1 is 0%, and rapidly increases to 40% from here toward the center of the plate thickness, and for a while at 40%. After that, it changes from 40% to 60%, and the inner layer part 2 (intermediate layer of the molded product) has a content of 60%.

  Further, the thermoplastic resin of the outer layer portion 3 is mixed with powder of metal (for example, aluminum, copper, iron, etc.) or mineral (for example, sapphire, etc.). Instead of the fibers appearing, the metal or mineral powder appears.

  Next, the manufacturing method of the fiber reinforced resin structural member 1 which consists of this structure is demonstrated.

  First, in order to shape | mold the inner layer part 2 (core material), as shown in FIG.

  That is, a plurality of carbon fiber woven fabrics 4 and a plurality of thermoplastic resin sheets 5 are laminated as a “fiber structure” and set between the lower mold 8 and the upper mold 9 of the press die 7. From this state, the lower mold 8 and the upper mold 9 are heated to a predetermined temperature, and the laminated carbon fiber woven fabric 4 and the plurality of thermoplastic resin sheets 5 are pressed. As a result, the thermoplastic resin sheet 5 is melted and impregnated in the carbon fiber woven fabric 4 and shaped into a predetermined shape, thereby completing the molding of the inner layer portion 2 (core material).

  Next, the inner layer portion 2 (core material) is set in a molding die 11 as shown in FIGS. 5 and 6, and a thermoplastic resin mixed with carbon fiber is injected around the inner layer portion 2 to inject the outer layer portion. 3 is formed.

  First, the mold 11 will be described. The mold 11 includes a fixed mold 13 fixed to the fixed side 12 of the molding machine and a movable mold 15 fixed to the movable side 14. The movable mold 15 is provided with hot runners 13a and 15a through which molten resin flows.

  The hot runners 13a and 15a have central passages 13b and 15b and branch passages 13c and 15c that branch from the central passages 13b and 15b and extend to an injection space (cavity), respectively. The central passage 13b of the hot runner 13a of the fixed mold 13 is such that molten thermoplastic resin flows from one end on the right side in the figure, and an open / close valve 13d is arranged on the other end on the left side in the figure. It is installed. Further, the central passage 15b of the hot runner 15a of the movable die 15 is provided with an opening / closing valve 15d at one end on the right side in the drawing, and the central passage 13b of the hot runner 13a of the fixed die 13 as shown in FIG. It communicates in a clamped state.

  Further, the branch passage 13c of the hot runner 13a of the fixed mold 13 has the discharge port at the tip thereof facing the right side of the accommodated inner layer part 2, and the branch passage 15c of the hot runner 15a of the movable mold 15 is The discharge port at the distal end faces the left side of the accommodated inner layer portion 2. Opening / closing valves 13e and 15e are provided at the distal ends of the branch passages 13c and 15c, respectively. The discharge port of the fixed mold 13 and the discharge port of the movable mold 15 are provided at positions where the molds 13 and 15 face each other, and the molten resin is injected from both of the discharge ports to both sides of the inner layer portion 2. ing.

  Further, the fixed mold 13 and the movable mold 15 are provided with a holding mechanism 16 as “fixing means” for fixing the inner layer portion 2 (core material) to the mold 11. The holding mechanism 16 is provided so that the holding pin 16a protrudes and appears in the injection space, and the inner layer portion 2 is sandwiched and fixed from both sides by the holding pin 16a in a protruding state. The holding pin 16a is protruded by hydraulic pressure, pneumatic pressure, a spring or the like, and a part of the holding pin 16a on the front end side is pushed and immersed by the force of the injected molten resin.

  The outer layer portion 3 is formed around the inner layer portion 2 using such a mold 11 as follows.

  First, the inner layer portion 2 molded as described above is accommodated in the injection space of the molding die 11, and the plurality of holding pins 16 a of the holding mechanism 16 are hydraulically or the like while the fixed die 13 and the movable die 15 are clamped. The inner layer portion 2 is clamped from both sides and fixed.

  In this state, the fixed mold 13 and the movable mold 15 are heated, and molten resin mixed with carbon fiber and metal or mineral powder flows into the central passage 13b of the hot runner 13a of the fixed mold 13, and the open / close valve 13d. , 15d is opened to allow the molten resin to flow into the central passage 15b of the hot runner 15a of the movable die 15.

  At the same time, by opening the on-off valves 13e and 15e, the molten resin is injected into the injection space from the central passages 13b and 15b through the branch passages 13c and 15c. In this case, the molten resin is injected to both sides of the inner layer portion 2 from the discharge ports of the branch passages 13c and 15c on both sides of the inner layer portion 2, so that the molten resin is injected around the inner layer portion 2. .

  By injecting the molten resin to both sides of the inner layer portion 2 in this way, the molten resin can be easily spread over the entire circumference of the inner layer portion 2 and the thickness of the outer layer portion 3 is formed to be uniformly thin. You can also. For example, when the molten resin is injected only from one side of the inner layer part 2, it is necessary to cause the resin to flow to the opposite side of the inner layer part 2, and the molten resin can be easily spread over the entire circumference of the inner layer part 2. It is not easy, and in order to spread the molten resin around the entire circumference of the inner layer part 2 before the molten resin is cured, it is necessary to increase the thickness. Cannot be thinned.

  At this time, the holding pin 16a is retracted from the injection space by a part of the tip side of the holding pin 16a being pushed and immersed by the force of the injected molten resin, so that the holding pin 16a exists. It is possible to spread the molten resin where it was.

  Further, by injecting the molten resin to the entire circumference of the inner layer portion 2 in this way, the content ratio of the carbon fiber to the thermoplastic resin is increased from the outer surface of the fiber reinforced resin structural member 1 toward the center portion of the plate thickness. The fiber content will increase. The thermoplastic resin of the outer layer part 3 is mixed with powder of metal (for example, aluminum, copper, iron, etc.) or mineral (for example, sapphire, etc.). Instead of appearing, the metal or mineral powder will appear. This is because when the molding die 11 is heated, the molten resin travels around the surface of the molded product (portion in contact with the molding die 11), so that the carbon fiber does not appear on the surface, or the metal mixed in the molten resin or This is because mineral powder appears.

  Then, the outer layer part 3 is shape | molded so that the circumference | surroundings of the inner layer part 2 may be covered by cooling this fixed mold | type 13 and the movable mold | type 15, and cooling and hardening a molten resin. Next, the molding is completed by removing the molded fiber-reinforced resin structural member 1 by moving the movable mold 15 and releasing the mold.

  In such a fiber reinforced resin structural member 1, the inner layer portion 2 is composed of a core material in which a fibrous structure is impregnated with a thermoplastic resin, and the outer layer portion 3 is made of a thermoplastic resin containing long fibers. Compared to aluminum die-casting, the weight can be reduced and the manufacturing cost can be reduced, and the strength can be improved compared to conventional injection-molded products. Mass production is possible compared to the molding of thermosetting resin. Is inexpensive and can be molded into a complicated shape.

  FIG. 7 shows the relationship between the fiber length and the fiber reinforcement effect coefficient in this case. As shown in this figure, the fiber reinforcement effect coefficient shows a large elongation up to a fiber length of about 4 mm, and a fiber having an arbitrary fiber length is used so that the strength is improved.

  FIG. 8 shows the relationship between the carbon fiber content and the tensile strength. As shown in this figure, when the carbon fiber content increases, the tensile strength increases.

  Furthermore, the content ratio of the carbon fiber to the thermoplastic resin increases the strength and rigidity because the carbon fiber content increases from the outer surface of the fiber reinforced resin structural member 1 toward the center of the plate thickness. Can do.

  Furthermore, since the metal or mineral powder is mixed with the thermoplastic resin of the outer layer portion 3, long fibers are not exposed on the surface, and the metal or mineral powder appears. By adjusting the color, the color of the appearance can be adjusted.

  Moreover, since carbon fiber is used for the inner layer part 2 and the outer layer part 3, it is lightweight and can ensure intensity | strength effectively compared with another fiber.

  Furthermore, since the thermoplastic resin containing the long fibers constituting the outer layer portion 3 is injected and molded around the inner layer portion 2 into the mold 11, the fiber reinforced resin structural member 1 can be easily molded.

  Furthermore, by providing the holding mechanism 16, the inner layer portion 2 can be easily and stably disposed in the mold 11.

  Also, the injection molding of the outer layer part 3 is carried out by heating around the core material (inner layer part 2) from at least a pair of discharge ports (branch passages 13c, 15c) provided at substantially opposing positions of the fixed mold 13 and the movable mold 15. Since the plastic resin is injected, the thin outer layer portion 3 can be uniformly formed around the inner layer portion 2.

  In the above-described embodiment, the present invention is applied to an automobile gear box as the fiber reinforced resin structural member 1. However, the present invention is not limited thereto, and any other structural member that requires strength, weight reduction, or the like can be used. However, the present invention can be applied effectively.

  Further, as a fixing means for fixing the inner layer portion 2 to the mold 11, the holding mechanism 16 is provided on the mold 11 side. .

DESCRIPTION OF SYMBOLS 1 ... Fiber reinforced resin structural member 2 ... Inner layer part 3 ... Outer layer part 4 ... Carbon fiber woven fabric 5 ... Thermoplastic resin sheet 7 ... Press die 8 ... Lower die 9 ... Upper die
11 ... Mold
13 ... Fixed type
13a… Hot runner
13b ... Central passage
13c ... Branch passage
15 ... Moveable type
15a… Hot runner
15b ... Central passage
15c ... Branch passage
16 ... Holding mechanism (fixing means)
16a ... Holding pin

Claims (7)

A fiber reinforced resin structural member made of a composite material of resin and fiber,
A fiber reinforced resin comprising an inner layer portion made of a core material in which a fiber structure is impregnated with a thermoplastic resin, and an outer layer portion covering the periphery of the inner layer portion made of a thermoplastic resin containing long fibers. Structural member.   2. The fiber according to claim 1, wherein a content ratio of the fiber to the thermoplastic resin is such that a content rate of the fiber increases from an outer surface of the fiber reinforced resin structural member toward a center portion of a plate thickness. Reinforced resin structural member.   The fiber-reinforced resin structural member according to claim 1 or 2, wherein a metal or mineral powder is mixed with the thermoplastic resin of the outer layer portion.   The fiber-reinforced resin structural member according to any one of claims 1 to 3, wherein the fiber structure and the long fibers are carbon fibers. It is a manufacturing method of the fiber reinforced resin structure member according to any one of claims 1 to 4,
The inner layer portion, which is the core material molded in a predetermined shape in advance, is placed in a mold, and the thermoplastic resin containing the long fibers constituting the outer layer portion is injected into the mold and molded. The manufacturing method of the fiber reinforced resin structural member characterized by these.   6. The method for producing a fiber-reinforced resin structural member according to claim 5, further comprising a fixing unit that fixes the inner layer portion to the mold when the inner layer portion is disposed in the mold. .   The injection molding of the outer layer portion is performed by melting the thermoplastic resin containing the long fibers on both sides of the inner layer portion from at least a pair of discharge ports provided at positions substantially opposed to the fixed die and the movable die of the molding die. The method for producing a fiber-reinforced resin structural member according to claim 5 or 6, wherein the fiber-reinforced resin structural member is molded by injecting a resin.