JPH074998U - Fiber reinforced plastic truss member - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a truss member made of fiber reinforced plastic excellent in heat cycle resistance. [Structure] A cylindrical body 2 made of FRP or CFRP, a flange 3a, and a substantially cylindrical fitting portion 3b projectingly formed on one surface of the flange 3a. A screw hole 3c is formed in the center. A metal end fitting 3 and a locking fitting 5 fixedly provided on the opposite side of the fitting 3b of the end fitting 3 are provided. In the fiber-reinforced plastic truss member 1 configured by inserting and locking 3b, the inner peripheral surface of the cylindrical body 2 that abuts each other and the inner peripheral surface of the cylindrical body 2 of the outer peripheral surface of the fitting portion 3b of the end fitting 3 are tapered. Shaped locking portion 2a, and a tapered locking portion 3d on the outer peripheral surface of the fitting portion 3b.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a truss member made of fiber reinforced plastic suitable for a structure such as an aircraft or a space station that needs to be lightweight.

[0002]

[Prior art]

 FIG. 5 is a cross-sectional view of an end fitting mounting portion of an FRP truss member according to a conventional example.

The truss member 1 includes a tubular body 2 made of fiber reinforced plastic such as FRP or CFRP, end fittings 3 fitted and fixed in openings at both ends of the tubular body 2, and bolts 4 attached to the end fittings 3. It is constituted by a locking metal fitting 5 which is screwed and locked through. Reference numeral 9 is a detent nut of the locking fitting 5.

More specifically, the end fitting 3 includes a flange portion 3a and a fitting portion 3b formed on one side surface of the flange portion 3a in the axial direction so as to have a screw hole at the center portion in the axial direction. Forming 3c.

Then, the fitting portion 3b is fitted into the inner peripheral portion from the opening of the end portion of the cylindrical body 2, and the surface of the flange portion 3a on the outer peripheral side of the fitting portion and the end surface of the cylindrical body 2 are in contact with each other. Attach the end fitting 3 to the end of the cylinder 2.

A locking pin can be inserted into the locking hole 5a at the center of the locking metal member 5.

[0007]

[Problems to be solved by the device]

 In this way, the structure can be made lighter by making the tubular body 2 which is the main part of the truss member made of FRP or CFRP, but the end fitting 3 which is the joint portion needs to use metal. is there.

Generally, it is possible to fix the both by interposing an adhesive between the abutting surfaces of the inner peripheral portion of the cylinder and the fitting portion of the end fitting, but the two are in contact with each other horizontally in the axial direction. There is a problem with the heat cycle resistance if it is just fixed with a chemical.

That is, in a space structure, since there is a temperature cycle of about 300 ° C. in orbit, the cylindrical body 2 is subjected to thermal stress due to repeated expansion and contraction, and the adhesive is peeled off, and The end fittings may come off.

The present invention has been made based on such a background, and an object thereof is to provide a truss member made of fiber reinforced plastic excellent in heat cycle resistance.

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a tubular body made of fiber reinforced plastic, an end metal member including a flange portion and a fitting portion projectingly formed on one side surface of the collar portion in the axial direction, and the aforementioned collar portion. And a locking metal fitting provided on the opposite side of the fitting portion of the end fitting based on the above, and the fitting portion of the end fitting is fitted in the tubular end opening. In the strengthened plastic truss member, of the inner peripheral surface of the cylinder and the outer peripheral surface of the fitting portion of the end fitting that are in contact with each other, the inner peripheral surface of the cylinder is tapered so that the hole diameter decreases toward the end of the cylinder. And a tapered locking part on the outer peripheral surface of the fitting part of the end fitting so as to be in close contact with the taper of the locking part on the inner peripheral surface of the cylinder. It is a digit.

[0012]

[Action]

 The taper locking part on the inner peripheral surface of the cylinder and the taper locking part on the outer peripheral surface of the fitting part of the end fitting are fitted together to reliably prevent the axial disengagement.

[0013]

Embodiment An embodiment of the present invention will be described below with reference to the drawings. Incidentally, the same parts as those of the conventional example shown in FIG.

FIG. 1 is a sectional view of an end fitting mounting portion of a fiber-reinforced plastic truss member according to an embodiment, and FIG. 2 is an enlarged sectional view of a main part thereof.

In the present embodiment, an engaging portion 2a formed in a tapered shape is provided on the inner peripheral surface of the end of the tubular body 2 so that the hole diameter becomes smaller toward the end of the tubular body 2. The outer peripheral surface of the fitting portion 3b of the end fitting 3 corresponding to the locking portion 2a is formed in a tapered shape so as to be in close contact with the taper of the locking portion 2a on the inner peripheral surface of the tubular body 2. A stopper portion 3d is provided, and the stopper portion 2a and the stopper portion 3d are fitted to each other so as to lock them.

As described above, the inner peripheral surface of the tubular body 2 and the outer peripheral surface of the fitting portion 3b are not brought into contact with each other in parallel with each other in the axial direction, but by the tapered locking portions 2a and 3d. Since it is locked, it can be prevented from coming off in the axial direction.

It is effective that the inner peripheral surface of the cylindrical body 2 and the outer peripheral surface of the fitting portion 3b for forming the engaging portions 2a and 3d have a taper angle of 15 degrees or more.

Needless to say, if the adhesive is applied to the contact surfaces of the two, the retaining effect is enhanced.

When the cylindrical body 2 is manufactured, a cutout is partially provided in the circumferential direction of the outer peripheral end of the fitting portion 3b of the end fitting 3, and the cutout is made of a brazing material. The cylinder 10 is fitted, and the carbon fiber is wound around the outer circumference thereof.

After the winding of the carbon fiber is completed, the brazing material is melted by heating the truss member 1 and is made to flow out from the cylindrical body 2 through the screw hole 3c to the outside.

As shown in FIG. 2, the carbon fibers forming the tubular body 2 have a three-layer structure (strictly, a four-layer structure) in the winding direction.

The innermost layer 2b and the outermost layer 2b 'have a winding direction of ± 45 degrees. Specifically, for example, the innermost layer 2b has a winding direction of +45 degrees, and the outermost layer 2b 'has a winding direction of -45 degrees which intersects +45 degrees.

The winding direction of the intermediate layer 2c outside the innermost layer 2b is the axial direction (0 degree).

The winding direction of the intermediate layer 2d further outside the intermediate layer 2c is the circumferential direction (90 degrees).

By thus forming the carbon fiber into a multilayer structure having the intermediate layers 2c and 2d whose winding directions are changed, the strength of the FRP or CFRP cylinder 2 can be further increased.

FIG. 3 is a front view showing a part of the structure incorporating the truss member 1, and FIG. 4 is a sectional view taken along the line AA of FIG.

Between the cylindrical first frame 6 and the cylindrical second frame 7 parallel to the first frame 6, a large number of trusses are arranged so that the locking metal fittings 5 and 5 face each other. The member 1 is attached in a zigzag shape.

That is, each of the locking pieces 6a, 7a having symmetrical taper surfaces formed on the outer peripheral surfaces of the first frame 6 and the second frame 7 has a pair of locking metal fittings of the adjacent truss members 1, 1. 5 and 5 are locked.

Specifically, as shown in FIG. 4, a locking piece 6a (same for 7a) is fitted in a groove in the center of the locking metal fitting 5, and a pin 8 is inserted between the two to lock the two. is doing.

[0030]

[Effect of device]

 As described above, according to the present invention, since the tapered engagement portions that engage with each other are formed on the inner peripheral surface of the cylinder and the outer peripheral surface of the end fitting, both of them are prevented from coming off in the axial direction. It is possible to provide a truss member having excellent heat cycle resistance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an end fitting mounting portion of a fiber reinforced plastic truss member according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of an essential part of an end fitting of a fiber-reinforced plastic truss member according to an embodiment of the present invention.

FIG. 3 is a front view showing a part of a structure incorporating a truss member.

4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is a cross-sectional view of an end fitting mounting portion of a fiber-reinforced plastic truss member according to a conventional example.

[Explanation of symbols]

 1 Truss member (truss member made of fiber reinforced plastic) 2 Cylindrical body 2a Locking part 3 End fitting 3a Collar part 3b Fitting part 3d Locking part 5 Locking fitting

Claims (1)

[Scope of utility model registration request] 1. A tubular body made of fiber reinforced plastic, an end fitting including a flange and a fitting portion projectingly formed on one side surface of the flange in the axial direction, and the end fitting based on the flange. A truss member made of fiber reinforced plastic, which comprises a fitting fitting provided on the opposite side of the fitting portion, and the fitting portion of the end fitting is fitted in the tubular end opening. Of the contacting inner peripheral surface of the cylinder and the outer peripheral surface of the fitting portion of the end fitting, the inner peripheral surface of the cylinder is provided with a taper-shaped locking portion having a hole diameter that decreases toward the end of the cylinder. The fiber-reinforced plastic is characterized in that a locking portion formed in a tapered shape is provided on the outer peripheral surface of the fitting portion of the end fitting so as to be in close contact with the taper of the locking portion on the inner peripheral surface of the cylinder. Truss member.