JPWO2015019479A1 - Joint structure - Google Patents

Abstract

The present invention provides a fast and reliable FRP pipe and metal member fastening structure that is small and simple, and an FRP structure including such a fastening structure. A straight pipe-shaped FRP pipe, and a taper surface inclined at substantially the same angle as the metal member, the metal member consisting of a split piece taper toward the longitudinal axis direction of the FRP pipe disposed around the FRP pipe The fastening structure is configured by inserting the metallic joint and the joint in a manner of fitting in a tubular metallic joint having the inner side. As a result, it is possible to achieve a compact and simple fastening and improve the reliability of the fastening structure.

Description

The present invention relates to a joint structure, and more particularly to a joint structure suitable for fastening with a fiber-reinforced plastic member.

  Fiber reinforced plastic (hereinafter referred to as FRP) is not only excellent in specific strength and specific rigidity, but also excellent in corrosion resistance, and is therefore widely used in various fields. In the future, it is expected to expand the application to construction machines and buildings used in environments with severe loads such as fatigue and impact. In particular, FRP pipes can be manufactured at low cost by pultrusion molding, filament winding molding, sheet winding molding, and the like, and have a high degree of freedom in length, thickness, and cross-sectional shape, and thus can be applied to various structural members.

  When an FRP pipe is used as a structural member, the reliability of the joint portion is a major issue. When the FRP pipe is fastened, there are cases where the reinforcing fiber is cut by the processing and the strength is remarkably lowered by the method of screwing the joint portion to fasten or the method of pinning by drilling.

  As means for solving such problems, a tapered portion is provided at the end of the FRP pipe by changing the diameter of the FRP pipe itself in the longitudinal direction, and the FRP pipe and the joint member are fastened using the tapered portion. (Patent Document 1).

On the other hand, a structure has been proposed in which an FRP pipe and a metal member are fastened in such a manner that the pipe is clamped by a metal joint from both the inside and outside of the FRP pipe (Patent Document 2).

JP-A-5-164116 JP 2011-37313 A

  In the technique according to Patent Document 1, when a compressive load is applied to the FRP pipe, when the compressive load is supported at the end of the FRP pipe, the diameter of the FRP pipe itself is changed in the longitudinal direction to form a tapered portion. Therefore, there is a possibility that FRP compressive fracture occurs from the end. This is because FRP causes local buckling of the fiber and breakage between layers when the compressive force is applied to the end portion where the fiber is exposed, and the compressive strength is significantly reduced.

  In the technique according to Patent Document 2, it is necessary to provide a slit in the outer joint in order to apply a radial compressive force to the outer peripheral surface of the FRP pipe, and the cross-sectional area of the fastening structure may increase.

An object of the present invention is to provide a joint structure that is compact and can be easily fastened and has a highly reliable fastening structure.

  In order to achieve the above object, according to the present invention, a straight fiber reinforced plastic pipe having a uniform outer diameter, a first joint member facing one end of the pipe, and a longitudinal direction of the pipe An intermediate member disposed around the pipe so as to be in contact with the pipe, and the intermediate member has a tapered portion whose diameter gradually increases from the other side of the pipe toward the one side. The second joint member and the first joint member have a second joint member in contact with the taper portion, and the second joint member and the pipe are pressed against each other via the taper portion. It was configured to be fastened.

Specifically, a metal member composed of a straight pipe-shaped FRP pipe and divided pieces tapered toward the longitudinal axis direction of the FRP pipe disposed around the FPR pipe is substantially the same as the metal member. It is constructed by inserting a tubular metallic joint having a tapered surface inclined at an angle inside and engaging the metallic joint with the joint in a fitting manner. This is achieved by the fastening structure and the FRP structure including the fastening structure.

According to the present invention, by engaging the joint, a compressive force in the joint radial direction acts on the contact surface between the member disposed around the FRP pipe and the FRP pipe. It becomes possible to do. At the same time, since it is not necessary to perform complicated processing on the FRP pipe and the joint, the fastening structure can be made smaller and more reliable.

External view of Example 1 Sectional view of Example 1 Sectional drawing of Example 2 AA sectional view in FIG. Sectional drawing of Example 3 Sectional drawing of Example 3 Sectional drawing of Example 3 Sectional drawing of Example 4 Sectional drawing of Example 4 Sectional drawing of Example 4 Sectional drawing of Example 5 Sectional drawing of Example 5 Sectional drawing of Example 6 Enlarged view of part A in FIG. External view of Example 7 Sectional drawing of Example 7 Sectional drawing of Example 7 Sectional drawing of Example 7 Sectional drawing of Example 8 Sectional drawing of Example 8 Sectional drawing of Example 9 Sectional drawing of Example 10 Sectional drawing of Example 11

Hereinafter, an example of a fastening structure according to the present invention will be described with reference to the drawings.

  1 and 2 show a fastening structure 1 as a first embodiment. The FRP pipe 2 (fiber reinforced plastic pipe 2) has a straight pipe shape, and the outer diameter is uniform d1 in the longitudinal direction. The inner diameter is also uniform d2. The metal member 3 is formed of two members having the same shape, and each has a shape in which the cross-sectional area gradually increases in the downward direction on the paper (also referred to as the Y direction for convenience). The metal member 3 has a tapered portion 3-1 by gradually increasing the cross-sectional area in the downward direction on the paper surface (Y direction). The inner diameter of the metal member 3 is a substantially constant curvature radius d1 (substantially the same as the outer diameter of the FRP pipe 2), and the inner diameter of the metal member 3 is formed so as to be in contact with the outer diameter of the FRP pipe 2 on the surface. Here, the virtual diameter equivalent of the bottom is defined as r.

  The outer joint 4 is made of a metal, and a space is formed on the inner side so that the cross-sectional area gradually decreases in the downward direction (Y direction). The outer joint 4 has a tapered portion 4-2 that gradually increases the inner diameter in the downward direction (Y direction) in the drawing by gradually reducing the cross-sectional area. The taper portion 3-1 of the metal member 3 and the taper portion 4-2 of the outer joint 4 have the same inclination. When the metal member 3 is installed in contact with the outer joint 5 and the outer joint 4 is fastened to the inner joint 5, the tapered portion 3-1 and the tapered portion 4-2 are in surface contact with each other. It is configured. An inner diameter d3 of the lower end (Y direction) of the taper portion 3-1 is formed smaller than the above-described virtual diameter equivalent r. A female screw 4-1 is cut inside the lower joint (Y direction) end of the outer joint 4.

  The inner joint 5 is made of metal and has a cylindrical shape. A male screw 5-1 is cut at the end of the inner joint 5 from the top to the top (X direction). The female screw 4-1 and the male screw 5-1 are formed to fit each other. Therefore, by rotating the female screw 5-1, the inner joint 5 moves in the paper surface upward direction (also referred to as the Y direction for convenience) with respect to the outer joint 4. The inner joint 5 and the outer joint 4 are structured to be fastened to each other at a predetermined moved position.

  As described above, the fastening structure 1 shown as the first embodiment in FIGS. 1 and 2 includes the straight pipe-shaped FRP pipe 2 and the FRP disposed around the FRP pipe as shown in the appearance and cross-sectional shape thereof. A metal member 3 made of a split piece provided with a taper in the longitudinal direction of the pipe is inserted inside a tubular metal outer joint 4 having a tapered surface inclined at substantially the same angle as the metal member. In this embodiment, the metal inner joint 5 having the threaded portion 5-1 on the outer surface is engaged with the joint.

As a result, when a tensile force in the longitudinal axis direction acts on the FRP pipe 2, a high fastening force is generated by the frictional force acting between the outer joint 4 and the tapered surface of the metal member 3. Further, when the outer joint 4 and the inner joint 5 are engaged, the inner joint 5 and the metal member 3 are in strong contact with each other. As a result, even when a compressive force in the longitudinal direction is applied to the FRP pipe 2, the taper surfaces of the outer joint 4 and the metal member 3 do not come off, so that the looseness is not easily lost. Therefore, there is an advantage that compression fracture at the end of the FRP pipe 2 can be prevented.

  Examples 2 to 11 will be described below. The second to eleventh embodiments will be described with a focus on differences from the first embodiment. Therefore, the part in which the description is omitted is basically the same as in the first embodiment.

The fastening structure 1 shown as Example 2 in FIGS. 3 and 4 is an embodiment in which a columnar or tubular metal rod 6 is arranged inside the FRP pipe 2 in the fastening structure of Example 1 as shown in the cross-sectional shape thereof. is there. As a result, a reaction force can be applied by the metal rod 6 to the compressive force applied to the FRP pipe 2 from the metal member 3 during fastening, so that the fastening force can be improved.

  The fastening structure 1 shown as Example 3 in FIGS. 5-7 is the implementation which reduced the thickness of the circumferential direction edge part of the metal member 3 in the fastening structure of Example 1 or Example 2 as shown in the cross-sectional shape. It is a form.

In the embodiment shown in FIG. 5, a taper is provided at a part of the circumferential end, and in the embodiment shown in FIG. 6, the thickness is continuously reduced by providing a curved portion at the end. In the embodiment shown in FIG. 7, the portion from the end to a certain distance is thinned with a certain thickness. Thereby, the stress concentration in the vicinity of the end when fastening or an external force is applied to the FRP pipe 2 can be reduced, and damage to the FRP pipe 2 starting from the stress concentration portion can be prevented.

  The fastening structure 1 shown as the fourth embodiment in FIGS. 8 to 10 is, as shown in its cross-sectional shape, in the fastening structure of the first or second embodiment, the joint member extends from the fastening portion to the longitudinal direction end of the metal member 3. It is embodiment which provided the site | part which protrudes in a direction.

In the embodiment shown in FIG. 8, a protrusion 7a having a taper inclined at an angle larger than the taper surface of the fastening portion is provided, and in the embodiment shown in FIG. 9, the protrusion 7b having a thickness continuously reduced by a curved portion. Is provided. Further, in the embodiment shown in FIG. 10, a protruding portion 7c having a constant thickness is provided. Thereby, when a bending load is applied to the FRP pipe 2 at the time of fastening, the stress concentration at the end of the fastening portion can be reduced, and damage to the FRP pipe 2 starting from the stress concentration portion can be prevented.

  The fastening structure 1 shown as the fifth embodiment in FIGS. 11 and 12 has a slit in the longitudinal end portion or the circumferential end portion of the metal member in the fastening structure of the first embodiment or the second embodiment as shown in the cross-sectional shape thereof. In this embodiment, 8a or 8b is provided.

By providing the slit, when the bending load is applied to the FRP pipe 2 at the time of fastening, the stress concentration at the end of the fastening portion or the end of the metal member 3 can be reduced, and the FRP starting from the stress concentration portion. Damage to the pipe 2 can be prevented. Further, both of the slits 8 a and 8 b may be provided in the metal member 3.

  In the fastening structure 1 shown as Example 6 in FIGS. 13 and 14, as shown in its cross-sectional shape, the metal member 3 is connected to the metal member 3a and the metal member 3b arranged in series with respect to the longitudinal direction of the joint structure. This is a divided embodiment. A taper is provided on the outer surface of the metal member 3b, and a taper that is inclined at substantially the same angle as the taper and is shorter than the taper is provided inside the longitudinal end of the metal member 3a. Yes.

Thereby, when a bending load is applied to the FRP pipe 2 at the time of fastening, the stress concentration at the end of the fastening portion can be reduced, and damage to the FPR pipe 2 starting from the stress concentration portion can be prevented. Further, as shown in FIG. 14, by increasing the taper angle provided on the metal member 3b than the taper angle provided on the metal member 3a, the compressive force applied to the FRP pipe 2 from the metal member 3b is increased. , The fastening force can be improved.

  The fastening structure 1 shown as Example 7 in FIG. 15 to FIG. 18 divides the metal member 3 into a metal member 3c and a metal member 3d in the radial direction of the joint structure, as shown in the appearance and the cross-sectional shape. It is embodiment which has arrange | positioned the metal member in parallel with respect to the longitudinal direction of the joint structure.

  In the embodiment shown in FIGS. 15 and 16, the area of the outer surface of the metal member 3d is larger than the inner surface of the metal member 3c. In the embodiment shown in FIG. It is divided into. As a result, stress concentration at the end of the fastening portion and at the end of the metal member 3d at the time of fastening or when an external force is applied to the FRP pipe 2 can be reduced, and damage to the FPR pipe 2 starting from the stress concentration portion can be prevented.

  In the embodiment shown in FIG. 18, curved portions having different curvatures are provided on the outer side and the inner side of the metal member 3 d, respectively, and the fastening can be performed even when the curvatures of the inner surface of the joint 4 and the outer surface of the FPR pipe 2 are different.

In the above embodiment, by reducing the thickness of the metal member 3d, the followability of the metal member 3d with respect to the cross-sectional shape of the FRP pipe 2 is improved, and the outer surface of the FRP pipe 2 and the inner surface of the metal member 3d are surely secured. It becomes possible to make it contact.

  The fastening structure 1 shown as Example 8 in FIG. 19 and FIG. 20 has the said metal member or said metal on the contact surface of the metal member 3 and FRP pipe 2, or the metal rod 6, and FRP pipe 2, as shown in the sectional drawing. This is an embodiment in which a metal film 9 having higher thermal conductivity than a rod is arranged.

  It is known that when a fatigue load acts on the FRP, the FRP and the resin constituting the FRP deteriorate due to the heat generated inside the resin and the heat generated due to the damage inside the FRP, and the fatigue life and fatigue strength of the FRP decrease. It has been. In the fastening structure shown in FIG. 19 and FIG. 20, even when a fatigue load is applied to the FRP pipe 2, heat can be radiated from the fastening structure by the metal film 9. It becomes possible to prevent the fatigue life and fatigue strength of the FRP pipe 2 from decreasing.

By arranging the metal film 9 on both the contact surface of the metal member 3 and the FRP pipe 2 and the contact surface of the metal rod 6 and the FRP pipe 2, or by projecting from the fastening portion in the longitudinal direction of the fastening structure. ， The heat dissipation effect can be improved. Moreover, in this embodiment, since the contact surface of the metal film 9 and the FRP pipe 2 can be firmly brought into contact by a compressive force, a high heat dissipation effect can be exhibited.

  The fastening structure 1 shown as Example 9 in FIG. 21 is the fastening structure shown in the said Examples 1-8 as shown in the cross-sectional shape, and the metal plate 10 is protruded radially around the outer joint 4. It is the arranged embodiment.

As a result, even when a fatigue load is applied to the FRP pipe 2 and heat is generated in the fastening portion, it is possible to dissipate heat from the outer surface of the outer joint 4 and to prevent deterioration of the FRP pipe 2 due to heat. Therefore, the fatigue life and fatigue strength of the fastening structure can be improved.

The fastening structure 1 shown as Example 10 in FIG. 22 is a fixed structure between the end of the FRP pipe 2 and the inner joint 5 in the fastening structure shown in Examples 1 to 9 as shown in the sectional shape thereof. This is an embodiment in which a gap is provided. As a result, when a compressive load is applied to the FRP pipe 2, no compressive force is applied to the end of the FRP pipe 2, so that it is possible to prevent the FRP pipe 2 from being compressed and broken from the end. it can.

Example 11 shown in FIG. 23 is an FRP structure configured by connecting the fastening structure shown in Examples 1 to 10 and the structure 12 as shown in the cross-sectional shape thereof.

In each of the above embodiments, the cross section of the FRP pipe is circular or elliptical, but may be a polygonal cross section such as a quadrangle. In this case, a metal member having a circular outer tapered surface and a polygonal inner surface may be disposed around the FRP pipe.

The fastening structure according to the present invention has advantages such as easy manufacture, simple fastening, and high reliability.

DESCRIPTION OF SYMBOLS 1 ... Fastening structure, 2 ... FRP pipe, 3, 3a, 3b, 3c, 3d ... Metal member, 4 ... Outer joint, 5 ... Inner joint, 6 ... Metal rod, 7a, 7b, 7c ... Projection part, 8a, 8b ... Slit, 9 ... Metal film, 10 ... Metal plate, 11 ... Gap, 12 ... Structure

Claims (10)

A straight fiber reinforced plastic pipe having a uniform outer diameter, a first joint member facing one end of the pipe, and the pipe in contact with the pipe over the longitudinal direction of the pipe. An intermediate member disposed around, the intermediate member having a tapered portion whose diameter gradually increases from the other side of the pipe toward the one side, and a second joint member in contact with the tapered portion; A joint structure, wherein the second joint member and the first joint member are fastened so that the second joint member and the pipe are pressed against each other via the tapered portion.
The joint structure according to claim 1, wherein a columnar or tubular metal bar having the same cross-sectional shape as the inside of the pipe is fitted into the inside of the pipe.
3. The joint structure according to claim 1, wherein a thickness of an end portion in a circumferential direction of the intermediate member disposed around the pipe is reduced.
3. The method according to claim 1, wherein a portion projecting from the fastening portion in the longitudinal direction of the joint structure is provided at a longitudinal end portion of the intermediate member arranged around the pipe. Joint structure.
3. The fastening structure according to claim 1, wherein a slit-like recess is provided at a longitudinal end or a circumferential end of the intermediate member arranged around the pipe. A characteristic joint structure.
3. The outer surface of one member according to claim 1, wherein the intermediate member arranged around the pipe is divided into two members arranged in series with respect to the longitudinal direction of the joint structure. And the other member is in contact with the taper surface of the member through a taper surface that is shorter than the taper provided at the end in the longitudinal direction and is inclined at substantially the same angle as the taper. A joint structure characterized by that.
3. The intermediate member arranged around the pipe according to claim 1, wherein the intermediate member is divided into two members arranged in parallel with respect to the radial direction of the joint structure, and one member is arranged on the outer side thereof. A joint structure, wherein the joint member is in contact with the joint through a taper provided on the surface, and the other member is in contact with the inner surface of the member through an outer surface having a larger area than the inner surface of the member. .
8. The intermediate member according to claim 1, wherein the intermediate member is a metal member, and the metal member and the contact surface of the pipe or the contact surface of the metal rod and the pipe or the contact surface of both of the metal members. A joint structure in which a metal having higher thermal conductivity than a member or a metal rod is disposed.
9. The joint structure according to claim 1, wherein the intermediate member is a metal member, and a radially projecting metal plate is disposed on an outer surface of the metal joint. 10.
  10. The joint structure according to claim 1, wherein a constant gap is provided between an end portion of the pipe and a joint in a joint longitudinal direction.

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