JP2006272656A - Metal/resin composite pipe and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a metal outer pipe and an FRP inner pipe of a metal/resin composite pipe from being released apart in a cooling process after thermal molding and also, the buckling of the inner pipe/breakage of a material from occurring, in the metal/resin composite pipe. <P>SOLUTION: When the metal outer pipe and the FRP inner pipe are molded by heat and under pressure, a fiber-reinforced resin whose ratio of compression strength to compression modulus in the pipe axial direction can meet a specified relationship, is sandwiched between both outer/inner pipes as a buffer layer. Consequently, the compression load of the outer pipe by heat shrinkage in the pipe axial direction, is absorbed by the compression and shear deformation of the buffer layer. Besides, in the pipe axial direction of the composite pipe, the value (Rc2) of the compression strength/compression modulus of a second fiber-reinforced resin is higher than the value (Rc1) of the compression strength/compression modulus of a first fiber-reinforced resin. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composite pipe formed by integrally heating and pressure-molding a metal and a resin and a method for manufacturing the same.

  In order to enjoy the slidability, solvent resistance and workability of metal materials and the high specific strength, specific rigidity and heat distortion resistance of fiber reinforced resin (hereinafter referred to as “FRP”), A composite tube in which an FRP tube is combined is provided.

  The manufacturing method of such a composite pipe is roughly classified into four types: (1) adhesion method, (2) cladding method, (3) plating method, and (4) pressure bonding method.

(1) The bonding method is a manufacturing method in which an adhesive is applied to the surface of the FRP tube and this is adhered to the inner peripheral surface of the metal tube. However, in order to evenly bond the FRP tube and the metal tube, it is necessary to smoothly polish the outer surface of the FRP tube, resulting in damage to fibers in the resin and an increase in processing cost. In addition, since the strength and rigidity of the adhesive is lower than those of metal pipes and FRP pipes, there is a problem that the adhesive strength of both pipes, particularly the interlaminar shear strength, is not sufficient.

(2) The cladding method is a manufacturing method in which a metal tube and an FRP tube are formed to fit together, and the FRP tube is press-fitted into the metal tube. In the case of such a manufacturing method, strict tolerance management is required, and the processing cost is increased. In addition, the problem of fiber damage caused by the need to polish the surface of the FRP tube also occurs in the same manner as in the above-described bonding method. Furthermore, since the metal tube and the FRP tube are only in contact with each other by the frictional force, it is difficult to obtain sufficient interlaminar shear strength between the two tubes.

(3) The plating method is a manufacturing method in which metal plating is performed on the surface of the FRP tube. However, when a metal is plated on the FRP surface, there is a problem that the bonding force between the two is significantly inferior to the case where a metal is plated on a metal material. Further, in order to obtain a metal layer having a sufficient thickness as a structural member by metal plating, the processing cost is extremely large and not realistic.

(4) The crimping method is a manufacturing method in which an FRP tube arranged on the inner peripheral surface of a metal tube is pressure-bonded integrally with the metal tube. Such a manufacturing method is excellent in terms of processing cost and high interlaminar shear strength of both pipes after molding.

  As a prior art using the pressure bonding method, Patent Document 1 (Japanese Patent Laid-Open No. 5-50511: paragraphs [0020], [0022], [0027]) discloses an invention relating to a method for producing a metal-coated fiber-reinforced resin cylindrical member. Patent Document 2 (Japanese Patent Laid-Open No. 8-114216: paragraphs [0009] and [0029]) describes inventions related to the composite roller and a method for manufacturing the same.

  In the invention described in Patent Document 1, a fiber-impregnated resin or a metal thin plate including a glass cloth prepreg sheet is impregnated as an inner tube, and a thermosetting resin such as an epoxy resin is impregnated as an adhesive layer for joining this to a metal outer tube. Each of the resin-impregnated reinforcing fibers is used. Further, it is disclosed that pressurization with compressed air is used in combination when the adhesive layer is heat-cured.

When the FRP roller is combined with the inner peripheral surface of the metal pipe, the invention described in Patent Document 2 eliminates the fiber disturbance by orienting the fibers in the circumferential direction of the innermost layer and the outermost layer of the FRP roller. It is possible to firmly bond the inner and outer tubes. As for the method for forming the inner and outer tubes, it is disclosed that the expansion cone is screwed and the expansion cam is rotated in a heated environment.
JP-A-5-50511 JP-A-8-114216

  In the pressure bonding method, when a metal outer tube and an inner tube made of FRP prepreg are to be strongly pressure-molded, the FRP base material (matrix) is a thermosetting resin or a thermoplastic resin. Regardless of this, the pressurizing operation is performed at a high molding temperature. At this time, due to the difference in coefficient of linear expansion (CTE) between the metal and FRP, in the cooling step after heating and pressure forming, separation between both tubes, buckling of the inner tube, or material destruction may occur.

As shown in FIG. 9, when both pipes are cooled from the state A of the composite pipe in which the metal outer pipe 10 and the FRP inner pipe 12 are pressure-bonded under heating, the outer part having a large CTE is obtained. Since the pipe 10 is greatly heat-shrinked along the direction of the pipe axis having a particularly long length, the peeling 11 (state B) is performed when the joining force between the two pipes is weak, and the buckling 13 ( This is because the material C breaks in the state C) or mainly in the outermost layer of the inner tube. As an example of the metal material, the CTE of stainless steel is 17 to 18 [10 ⁻⁶ / K], and the CTE of aluminum is 25 to 26 [10 ⁻⁶ / K]. In the case of carbon fiber reinforced plastic, CTE is extremely low, around 1 [10 ⁻⁶ / K].

  Here, in the case of the invention described in the prior art document 1, the fiber type and the orientation of the inner cylinder 1 and the resin-impregnated reinforcing fiber 2 are not particularly examined, and the respective compression elastic modulus and shear elastic modulus in the tube axis direction are not examined. In addition, since the glass cloth prepreg sheet is allowed to be used for both the inner cylindrical body 1 and the resin-impregnated reinforcing fiber 2, the above-described peeling, buckling, and material destruction may occur. was there.

  In the case of the invention described in the prior art document 2, the outermost layer (and the innermost layer) of the FRP pipe is fiber oriented in the circumferential direction, but the inner pipe is made of a single fiber reinforced resin. If the metal pipe that directly contacts the heat shrinks, if the rigidity of the composite pipe as a whole is to be maintained high, the problem that material breakage tends to occur especially in the vicinity of the outer layer of the inner pipe is inevitable. .

  In light of these problems of the prior art, in the present invention, a metal / resin composite pipe composed of a metal outer pipe and an FRP inner pipe is cooled after heat forming while maintaining its rigidity high. The object is to prevent peeling between both pipes in the process, buckling of the inner pipe, and material destruction.

  Therefore, in order to solve the above problems, the present inventor has intensively studied, and when the metal outer tube and the FRP inner tube are heated and pressure-molded, the ratio between the compression strength in the tube axis direction and the compression elastic modulus is a predetermined ratio. By sandwiching a fiber reinforced resin satisfying the relationship different from the inner tube as a buffer layer between the two tubes, the compressive load in the tube axis direction due to the thermal contraction of the outer tube is absorbed by the compression and shear deformation of the buffer layer. I came up with the knowledge that This also prevents the axial load caused by heat shrinkage of the outer tube from being directly applied to the inner tube, avoiding the inner / outer tube peeling, the inner tube buckling or material breakage. Since this means that it can be done, the present invention that solves the above-described problems has been completed based on this finding. In addition, by using a fiber reinforced resin instead of an epoxy-based adhesive as the buffer layer, the rigidity of the composite pipe as a whole is also ensured.

That is, according to the following invention, the above-described problems can be solved.
(1) A metal / resin composite in which an inner tube made of a first fiber reinforced resin is heated and pressure-molded on an inner peripheral surface of a metal outer tube with a buffer layer made of a second fiber reinforced resin interposed therebetween A tube,
Regarding the tube axis direction of the composite tube, the compression strength / compression modulus value (Rc2) of the second fiber reinforced resin is larger than the compression strength / compression modulus value (Rc1) of the first fiber reinforced resin. A metal / resin composite tube characterized by that.

The present invention includes the following related inventions as specific embodiments thereof.
(2) The metal / resin composite tube according to (1), wherein Rc2 is 1.5 times or more of Rc1.

(3) The metal / resin composite tube according to (1) or (2), wherein the outer tube, the inner tube, and the buffer layer have a rectangular cross-sectional shape perpendicular to the tube axis.

(4) The metal / resin composite tube according to any one of (1) to (3), wherein the inner tube is made of carbon fiber reinforced plastic and the buffer layer is made of glass fiber reinforced plastic.

(5) The metal / resin composite tube according to (4), wherein the ratio of the thickness of the inner tube to the buffer layer is 10: 1 to 100: 1.

(6) a first step of attaching an inner tube made of a first fiber reinforced resin around a core material provided with an internal pressure load means;
A second step of depositing a buffer layer made of a second fiber reinforced resin on the outer periphery of the inner tube;
A third step of inserting the inner tube with the buffer layer deposited inside the metal outer tube;
A fourth step in which the outer tube, the buffer layer and the inner tube are heated to a predetermined molding temperature (° C.), and these are integrally pressure-molded by the internal pressure load means;
A metal / resin composite pipe manufacturing method comprising a fifth step of aging at a temperature (° C.) of 40 to 80% of the molding temperature (° C.),
For the tube axis direction of the composite tube, the compression strength / compression modulus value (Rc2) after pressure molding of the second fiber reinforced resin is the compression strength / compression after pressure molding of the first fiber reinforced resin. A method for producing a metal / resin composite pipe, characterized by being larger than a value of elastic modulus (Rc1).

  When a metal outer tube and an FRP inner tube are pressure-formed in a heated environment, a metal tube with a large CTE undergoes a large thermal expansion deformation when heated to the molding temperature, and FRP with a small thermal deformation in that state. It is press-molded integrally with the made inner tube. According to the metal / resin composite tube according to the present invention, in the tube axis direction of the composite tube, the compression strength / compression modulus value (Rc2) of the buffer layer sandwiched between them is the compression strength / compression elasticity of the inner tube. It is characterized by being larger than the rate value (Rc1).

  As a result, when the entire composite tube is cooled from the heated / pressurized state and the outer tube contracts, the buffer layer is compressed and deformed by being dragged on the outer tube side due to the low compression elastic modulus. Since the side is held in a restrained state, the whole undergoes shear deformation in the tube axis direction. For this reason, the thermal stress generated between the metal outer tube and the FRP inner tube can be received as the compression and shear stress of the buffer layer and absorbed.

  FIG. 8 is an explanatory diagram showing the thermal deformation characteristics of the composite pipe according to the present invention. By sandwiching the buffer layer 14 between the outer tube 10 and the inner tube 12, compression and shear deformation of the buffer layer 14 due to thermal contraction due to cooling of the thermally expanded outer tube 10 (state A) occurs (state B). It shows how the thermal stress is absorbed.

  The stress applied to the buffer layer is generally the most critical compressive stress on the outermost surface in direct contact with the outer tube due to the magnitude of the strain. It is avoided that the buffer layer itself is destroyed even by compressive deformation. On the other hand, the compressive strength and shear strength of fiber reinforced resin generally have a positive correlation, and the buffer layer also has a high shear strength. However, the shear stress applied to the buffer layer from the outer tube is the thickness of the buffer layer. Since the load is applied to the entire buffer layer in inverse proportion to this, the value becomes small, and it is also avoided that the buffer layer itself is sheared.

  In conventional composite pipes that do not have such a buffer layer, material destruction of the outermost layer of the inner pipe due to stress overshoot that occurs at the start of cooling, or when the heat shrinkage strain of the outer pipe increases as cooling progresses, Peeling and buckling failure of the entire inner tube are particularly problematic, but the value of compressive strength / compression modulus (Rc) in the tube axis direction is large between the metal outer tube and the FRP inner tube as in the present invention. By providing the buffer layer, these problems can be solved.

  Further, by using the fiber reinforced resin as the buffer layer, the rigidity of the composite pipe as a whole can be ensured to be high as compared with the conventional method in which the inner / outer pipes are bonded with an adhesive. As a result, a metal / resin composite tube can be obtained that can enjoy all of the slidability, workability, solvent resistance of the metal outer tube, and the advantages of the high specific strength, specific rigidity, and heat distortion resistance of the FRP inner tube. .

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the following embodiments particularly with respect to the cross-sectional shape of the composite tube, the shape of the tube shaft, the specific method of the pressurizing means, and the like. The shape of the cross section (longitudinal cross section) along the tube axis of the metal / resin composite tube according to the present invention is shown in FIG. FIG. 2 shows the shape of a cross section (cross section) perpendicular to the tube axis. FIG. 2 corresponds to the AA cross section of FIG. 10 represents an outer tube, 12 represents an inner tube, 14 represents a buffer layer, and 20 represents a composite tube.

  The outer tube 10 is made of a metal material. As a result, advantages such as surface slidability, workability such as cutting, welding and plating, and solvent resistance in the case of a composite tube with resin can be obtained. The metal material is not particularly limited, and is appropriately selected from the viewpoints of use, availability, workability, and the like from, for example, stainless steel (SUS), steel, aluminum (aluminum), iron, copper, titanium, magnesium, or alloys thereof. it can.

  Further, the outer peripheral surface of the outer tube 10 is subjected to a mechanical polishing process such as a general wire brush or a sander, a degreasing process, a chemical conversion process such as sulfurization and oxidation, a plating process such as rust prevention, an anodizing process, and a surface effect process. Further, a film treatment or the like may be performed before molding. However, these surface treatments can also be performed after combining with the inner tube 12.

  On the other hand, the inner peripheral surface of the outer tube 10 is preferably subjected to degreasing treatment, primer treatment, mechanical polishing treatment, chemical conversion treatment, etc. in order to improve the adhesive strength with the buffer layer 14, but these are essential. This is not a process. Depending on the metal material used, suitable treatments such as non-chromate conversion treatment on aluminum pipes, phosphate coating treatment on steel pipes, and epoxy primer treatment on SUS pipes can be selected as appropriate.

  1 and 2, the vertical cross-sectional shape of the outer tube 10 is illustrated as a straight line and the cross-sectional shape is illustrated as a rectangle, but the shape of the outer tube 10 for achieving the object of the present invention is not limited to this. Alternatively, it may be a deformed tube whose longitudinal direction is not straight including the presence or absence of branching, a tube having a special cross-sectional shape such as a circular cross section or a triangular cross section, and the cross section may change along the longitudinal direction.

  The inner tube 12 is made of a first fiber reinforced resin material. Thereby, specific strength, specific rigidity, heat distortion resistance, corrosion resistance, chemical resistance, and the like exceeding the metal pipe can be obtained as a composite pipe by suitable setting of the base material, fiber type, and fiber orientation.

  Examples of the base material (matrix) used for the first fiber reinforced resin include epoxy resin (EP), phenol resin (PF), unsaturated polyester resin (FRP), alkyd resin, bismaleimide resin (BMI), cyanate resin, Thermosetting resin such as silicone resin, polyimide resin (PI), or polyurethane resin (PUR), or polyamide (PA), polyacetal (POM), polypropylene (PP), polysulfone (PSF), polybutylene terephthalate (PBT), Polycarbonate (PC), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyetherimide (PEI), polyethersulfone (PES), polyamideimide (PAI), polyarylate (PAR), polyarylenketo Can be used by mixing polyarylene sulfide or select one of a thermoplastic resin such as polyester (PET),, or two or more kinds. Among these, an epoxy resin or a cyanate resin is preferably used from the viewpoints of strength, moldability, and availability.

  In addition, for example, carbon fibers, aramid fibers, Kevlar fibers, natural fibers, boron fibers, ceramic fibers, silicon carbide fibers, or alumina fibers are used as the reinforcing fibers (fibers) used for the first fiber reinforced resin. .

  These reinforcing fibers may be any one type or a mixture of two or more types, and the fiber length is not limited to short fibers or long fibers. However, the viewpoint of increasing the specific strength and specific rigidity of the inner tube, and hence the composite tube. Therefore, it is preferable to use carbon fibers, aramid fibers, or silicon carbide fibers as long fibers.

  The method for combining the reinforcing fiber and the resin is not particularly limited. For example, the resin can be impregnated in a state where the reinforcing fibers are three-dimensionally knitted into the shape of the inner tube. However, the reinforcing fibers are aligned in one direction, and the base material is impregnated with the above-mentioned base material so as to be in a semi-cured state. A method of forming a plurality of prepregs and laminating them appropriately is preferable because it is easy to reinforce a predetermined direction of the composite pipe (for example, the pipe axis direction) by fiber orientation design.

  From the viewpoint of increasing the axial elastic modulus of the composite pipe 20 as a whole, the inner pipe 12 is formed by orienting a unidirectional (UD) material prepreg sheet of carbon fiber around the pipe axial direction (0 degree direction). Lamination molding is particularly suitable.

  The shape of the inner tube 12 is not particularly limited. In FIGS. 1 and 2, the vertical cross-sectional shape is a straight line and the cross-sectional shape is rectangular like the outer tube 10, but the shape is not limited to this, and similarly to the outer tube 10, a deformed tube or a special-shaped cross-sectional shape is used. It may be a tube. Moreover, it is not necessary to make the vertical or horizontal cross-sectional shape of the inner tube 12 the same as or similar to that of the outer tube 10, and the thickness, opening shape, and opening area required for the inner tube can be appropriately employed.

  The buffer layer 14 sandwiched between the outer tube 10 and the inner tube 12 and joining them is made of a second fiber reinforced resin material. Thereby, the thermal stress generated between the two pipes can be absorbed as compressive and shear stress on the buffer layer 14 while maintaining the rigidity of the composite pipe as a whole.

  For the base material (matrix) used for the second fiber reinforced resin, select one of the thermosetting resins or thermoplastic resins widely exemplified as the first fiber reinforced resin, or two or more types. It can be used by mixing.

  In addition, the reinforcing fibers (fibers) used for the second fiber reinforced resin can be used by mixing any one or a plurality of types of fiber materials widely exemplified as the first fiber reinforced resin. However, in order to achieve the object of the present invention, the buffer layer 14 is formed by impregnating the resin, and in a state where the buffer layer 14 is heated and pressure-molded, the compression strength / compression modulus value ( Rc2) needs to be larger than that of the inner tube 12 (Rc1). By making Rc2 larger than Rc1, it is possible to prevent peeling of the inner / outer tube and material destruction or buckling failure of the inner tube 12 in the cooling step after thermoforming.

  Therefore, glass fiber, aramid fiber, Kevlar fiber or carbon fiber as the reinforcing fiber, and epoxy resin, cyanate resin, or unsaturated polyester resin as the base material are the viewpoints of high compression and shear strength, and appropriate compression and shear modulus. Are preferably used.

  However, for example, when both the first and second fiber reinforced resins are carbon fibers impregnated with an epoxy resin, Rc2 is made larger than Rc1 as described above, so the content and / or orientation direction of the reinforced fibers. In particular, it is preferable to use a cloth material laminated in the 0/90 degree direction. In addition, glass cloth FRP, glass mat FRP, GFRP such as glass fiber reinforced thermoplastic resin, Kevlar cloth FRP, and the like are preferably used from the viewpoint of an appropriate balance between compression strength and compression elastic modulus.

  In the case of the conventional technique in which the inner / outer pipes are bonded with an adhesive, it is necessary to increase the thickness of the adhesive layer to match the shear strength in order to prevent the peeling of both pipes due to the shrinkage of the metal pipe. When the above-mentioned fiber reinforced resin is used for the buffer layer 14, the metal / resin composite pipe is high without reducing the elastic modulus of the outer tube alone. It is possible to obtain the advantage of the present invention that it can be maintained at a value. For example, when carbon fiber reinforced plastic is used as the inner tube, the outer tube is made of a single material without causing problems such as peeling even if the material of the outer tube is not only aluminum or titanium but also SUS having a high elastic modulus. A metal / resin composite tube that maintains the elastic modulus can be obtained.

  Although the buffer layer 14 is sandwiched between the outer tube 10 and the inner tube 12, the distribution and thickness thereof are not particularly limited. However, a space formed between the inner peripheral surface of the outer tube 10 and the outer peripheral surface of the inner tube 12 from the viewpoint of avoiding problems such as peeling of the inner / outer tube and maintaining high rigidity of the entire composite tube. It is preferable that the thickness of the buffer layer 14 is substantially uniform throughout, and the buffer layer 14 is sandwiched in such a space.

  In the invention according to claim 2 of the present invention, it is preferable that the Rc2 is 1.5 times or more, preferably 2.0 times, more preferably 3.0 times or more of Rc1. Thereby, the stress caused by the thermal contraction of the outer tube 10 can be sufficiently absorbed by the buffer layer 14, and problems of peeling of the inner / outer tube and destruction of the inner tube can be more preferably avoided.

  In the invention according to claim 3 of the present invention, the cross-sectional shapes of the outer tube, the inner tube and the buffer layer can be rectangular. This is because the composite pipe manufacturing method according to the present invention, which will be described later, employs a system in which an internal pressure is applied from the inside of the inner pipe 12, and therefore, unlike a conventional external pressure load system using a shrink tape or the like, a metal pipe is used. This is because, even though it is a composite pipe having an outer side and a rectangular cross section, a high pressure load is also applied to each corner portion, and peeling of each layer after molding can be eliminated.

  In the invention according to claim 4 of the present invention, it is preferable that the inner tube is made of carbon fiber reinforced plastic and the buffer layer is made of glass fiber reinforced plastic. Thereby, the object of the present invention can be achieved, in which the compression strength / compression modulus value (Rc2) of the buffer layer can be made larger than that (Rc1) of the inner tube.

  In the invention according to claim 5 of the present invention, the ratio of the thickness of the inner tube to the buffer layer is preferably 5: 1 to 200: 1, more preferably 10: 1 to 100: 1. . By keeping the thickness of the buffer layer having a relatively low elastic modulus within this range, the thermal stress between the inner tube 12 and the inner tube 12 caused by the thermal contraction of the outer tube 10 is buffered while maintaining the rigidity of the entire composite tube high. The layer 14 can be suitably absorbed by compression and shear deformation.

Regarding the invention according to claim 6 of the present invention,
A first step of depositing the inner tube 12 around the core material having the internal pressure loading means, a second step of depositing the buffer layer 14 on the outer periphery thereof, and a first step of inserting these into the outer tube 10 Three steps, a fourth step in which the outer tube 10, the buffer layer 14 and the inner tube 12 are heated to a predetermined molding temperature (° C.) while the inner pressure load means integrally press-molds them, and the molding temperature ( A metal / resin composite pipe comprising a fifth step of aging at a temperature (° C.) of 40 to 80% of
In the tube axis direction of the composite tube, it is preferable that the compression strength / compression modulus value (Rc2) of the buffer layer 14 after pressure molding is larger than that of the inner tube 12 (Rc1). . As a result, the metal / resin composite tube according to the present invention can be obtained and the prestress at the time of molding can be removed.

  The core material is a core provided with an internal pressure loading means 18 to be described later, and the inner tube 12 is formed on the outer periphery thereof by a method such as winding a prepreg. The material can be appropriately selected from metals such as SUS, copper, aluminum or ceramics, and resin materials.

  The internal pressure loading means is a means for pressing the laminated inner tube 12 and buffer layer 14 from the inside of the composite tube and press-molding integrally with the outer tube 10. Although a specific method is not particularly limited, a method in which a bar having a taper at the center of the separated core material or a method in which high-pressure air is poured into the central portion of the separated core material is preferably used.

  Aging removes the prestress which each material receives at the time of heating and pressure molding. The temperature and time are not particularly limited, but it is preferably 40 to 80% of the molding temperature in degrees Celsius. If the temperature is lower than this range, the effect of aging is not sufficiently obtained, and if the temperature is higher than this range, the amount of thermal expansion of the outer tube 10 increases again, and new pre-stress occurs.

  Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 3 is an explanatory view showing a first step of the manufacturing method according to the present embodiment. A rectangular column made of SUS (compression elastic modulus: 200 [GPa]) made of SUS having a height of 5 cm and a width of 10 cm is used as the core 16, and a unidirectional material prepreg made of the first fiber reinforced resin is wound around the surface. The inner tube 12 was formed. As the first fiber reinforced resin, an epoxy resin was used as a base material, and pitch-based carbon fibers (long fibers) were used as reinforced fibers. In order to reinforce the rigidity in the tube axis direction, which is the longitudinal direction, the prepreg is oriented at a rate of 1 layer in the 45 degree direction with respect to 2 layers in the 0 degree direction (tube axis direction), and the total thickness is 4 mm. Went. The compressive modulus of the prepreg in the fiber direction (0 degree direction) was 250 [GPa], and the compressive modulus in the axial direction of the inner tube formed by the above lamination was about 220 [GPa].

  FIG. 4 is an explanatory view showing the second step. A second fiber reinforced resin prepreg was wound around the surface of the inner tube 12 to form a buffer layer 14 having a rectangular cross section. As the second fiber reinforced resin, four types of FRP materials shown in Table 1 were used. That is, in Example 1, the fiber is a long fiber glass cloth and the matrix is an FRP using an unsaturated polyester resin, in Example 2, the fiber is a short fiber glass mat, the matrix is an FRP using an unsaturated polyester resin, and in Example 3, the fiber is carbon. Fiber (cloth material) and FRP using a matrix as a cyanate resin, and in Example 4, FRP using a fiber as a Kevlar cloth and a matrix as an epoxy resin were used. The buffer layer 14 was laminated with a thickness of about 0.2 mm on the entire surface of the inner tube 12.

For the first and second fiber reinforced resins used in Examples 1 to 4, the compressive strength [MPa] in the tube axis direction, the compressive elastic modulus [GPa], and the compressive strength / compressive elastic modulus (Rc1, Rc2) [10 ^{− 3} ], ratios of Rc2 and Rc1 are shown in Table 1, respectively.

  FIG. 5 is an explanatory view showing the third step. A rectangular tube made of SUS having a thickness of 5 mm was used as the outer tube 10, and this was put on the buffer layer 14. In order to reduce the stroke of the internal pressure loading means 18 to be described later, the inner peripheral surface of the outer tube 10 was cut so as to be in a state as close as possible to the buffer layer 14. The inner peripheral surface of the outer tube 10 was treated with an epoxy primer to improve the adhesion with the buffer layer 14.

  FIG. 6 is an explanatory view showing the fourth step. The core member 16 is provided with an internal pressure loading means 18 so that the inner tube 12 and the buffer layer 14 can be pressurized against the outer tube 10 from the inside. The inner pressure load means 18 applied a pressure of 30 [MPa] to the inner tube 12. Further, the entire composite tube was heated to 130 [° C.] by a heater (not shown) to form 180 [min].

  The internal pressure loading means 18 is shown in FIG. A method was adopted in which a tapered SUS bar 18 corresponding to the taper hole formed in the center of the core material 16 separated into four was inserted. A desired internal pressure can be applied to the core 16 and the inner tube 12 by inserting and removing the rod 18 by a predetermined length in the tube axis direction.

  After the molding time had elapsed, the bar 18 was extracted from the core 16 and aged at 80 [° C.] for 120 [minutes] to obtain metal / resin composite tubes according to Examples 1 to 4. Each of the obtained composite pipes was cut into several parts along the pipe axis, and the cross section was observed visually. As a result, neither delamination nor material destruction was observed, and it was confirmed that good molding was performed. . The composite pipes according to Examples 1 to 4 all maintain a high value of 204 [GPa] or more as the compressive elastic modulus in the pipe axis direction, which exceeds the elastic modulus of the SUS outer pipe alone. Met.

  The metal / resin composite tube according to the present invention has specific strength, specific rigidity, and heat distortion resistance due to FRP, and the outer tube is metal, so that general cutting can be performed. As a result, a composite pipe having a predetermined thickness and shape can be cut out, and since it is excellent in slidability and weldability, it can be used for a robot hand or a pipe as a structural member.

The longitudinal cross-sectional view of the composite pipe concerning embodiment of this invention The cross-sectional view of the composite pipe concerning embodiment of this invention Explanatory drawing which shows the 1st process of the manufacturing method of the composite pipe | tube concerning the Example of this invention. Explanatory drawing which shows the 2nd process of the manufacturing method of the composite pipe | tube concerning the Example of this invention. Explanatory drawing which shows the 3rd process of the manufacturing method of the composite pipe | tube concerning the Example of this invention. Explanatory drawing which shows the 4th process of the manufacturing method of the composite pipe | tube concerning the Example of this invention. Explanatory drawing which shows the internal pressure load means used for the Example of this invention Explanatory drawing which shows the heat deformation characteristic of the composite pipe concerning this invention Explanatory drawing showing delamination and buckling failure in a conventional composite pipe

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Outer pipe 11 Separation 12 Inner pipe 13 Buckling 14 Buffer layer 16 Core material 18 Internal pressure load means 20 Composite pipe

Claims (6)

The inner tube made of the first fiber reinforced resin is a metal / resin composite tube that is heated and pressed with the buffer layer made of the second fiber reinforced resin on the inner peripheral surface of the metal outer tube. And
Regarding the tube axis direction of the composite tube, the compression strength / compression modulus value (Rc2) of the second fiber reinforced resin is larger than the compression strength / compression modulus value (Rc1) of the first fiber reinforced resin. A metal / resin composite tube characterized by that. 2. The metal / resin composite tube according to claim 1, wherein Rc2 is 1.5 times or more of Rc1. The metal / resin composite pipe according to claim 1 or 2, wherein the outer pipe, the inner pipe and the buffer layer have a rectangular cross-sectional shape perpendicular to the pipe axis. 4. The metal / resin composite tube according to claim 1, wherein the inner tube is made of carbon fiber reinforced plastic and the buffer layer is made of glass fiber reinforced plastic. 5. The metal / resin composite pipe according to claim 4, wherein the ratio of the thickness of the inner pipe to the buffer layer is 10: 1 to 100: 1. A first step of attaching an inner tube made of a first fiber reinforced resin around a core material having an internal pressure load means;
A second step of depositing a buffer layer made of a second fiber reinforced resin on the outer periphery of the inner tube;
A third step of inserting the inner tube with the buffer layer deposited inside the metal outer tube;
A fourth step in which the outer tube, the buffer layer and the inner tube are heated to a predetermined molding temperature (° C.), and these are integrally pressure-molded by the internal pressure load means;
A metal / resin composite pipe manufacturing method comprising a fifth step of aging at a temperature (° C.) of 40 to 80% of the molding temperature (° C.),
For the tube axis direction of the composite tube, the compression strength / compression modulus value (Rc2) after pressure molding of the second fiber reinforced resin is the compression strength / compression after pressure molding of the first fiber reinforced resin. A method for producing a metal / resin composite pipe, characterized by being larger than a value of elastic modulus (Rc1).