JPH05269868A - Production of perforated hollow composite material - Google Patents

Abstract

PURPOSE:To obtain a product strong against stress concn. while dispensing with the cutting of a fiber by attaching pins to the outer peripheral surface of a mandrel in a detachable manner and winding a fiber impregnated with a resin around the outer peripheral surface of the mandrel to mold the same and subsequently detaching the pins from the outer peripheral surface of the mandrel or sinking them into the mandrel. CONSTITUTION:A fiber 13 impregnated with a resin is wound around the outer peripheral surface of a mandrel 11 having detachable or sinkable pins 12 provided to the outer peripheral surface thereof at predetermined positions by a filament winding method. After molding and curing, the pins 12 are detached from the outer peripheral surface of the mandrel 11 or sunk into the mandrel 11. The pins 12 attached to the mandrel 11 have various shapes according to uses but the leading end of each of the pins 12 is formed into a shape prevented from the hooking with a filament during winding, for example, a semispherical shape. When these pins are pulled out after curing and molding, a tube having bolt holes is obtained and perforation processing cutting the fiber becomes unnecessary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hollow material having a hole for torque transmission such as a propeller shaft of an automobile by using a composite material such as fiber reinforced plastic (hereinafter abbreviated as "FRP"). It is about.

[0002]

2. Description of the Related Art In recent years, the demand for weight reduction of automobiles has been increasing from the viewpoint of environmental protection and energy saving.
Consideration is being given to shifting to lightweight materials. One of these is the application of FRP to propeller shafts, which is expected to bring about not only the weight-saving effect by improving specific rigidity and specific strength, but also the improvement in riding comfort due to the increase in vibration damping, and is being put to practical use. ..

By the way, when the FRP tube is used as a torque transmission shaft, the method of joining the metal members at both ends is the most important technical problem. This requires that the joints have sufficient strength for the torque transmitted by the drive shaft, but the usual means (eg welding) used in the case of metal drive shafts is Is not applicable. Therefore, various joining methods have been proposed.

The simplest method is a method using an adhesive. As an example, a synthetic resin agent impregnated into a fiber is used.
A method of adhering a P shaft to a metal member has been proposed (Japanese Patent Publication No. 61-54965).

Further, as disclosed in Japanese Patent Laid-Open No. 55-159310, a sleeve having a large number of sharp pins arranged radially, and as disclosed in Japanese Patent Publication No. 62-53373. Provide teeth on the outer circumference of the sleeve,
A mechanical engagement method is used, such as a method in which the FRP tube is engaged with the inner surface, or a sleeve having a polygonal outer circumference as shown in Japanese Patent Laid-Open No. 55-159314. To increase the bonding strength, or as shown in FIG.
No. 30) is used to fix the joint between the FRP tube 2 and the yoke 3.

[0006]

However, each of the various conventional coupling methods has the following problems. First,
The method using only an adhesive has a problem in that it requires a long sleeve due to low adhesive strength, becomes heavy, and lacks reliability in repeated use over a long period of time. In addition, since the pin is arranged, a large stress concentration occurs in a portion of the inner surface of the FRP tube that abuts the tip of the pin, so that it cannot be used repeatedly. Also, teeth are provided on the outer circumference of the sleeve to
The method of biting into the inner surface of the P-tube has a problem that the fiber is cut at the part where the teeth hit and a crack is apt to occur due to stress concentration.

Further, the method of fixing the joint portion by using the bolt is the most reliable method as the torque transmitting means, but the conventional method is to form a hole in the joint portion after molding the FRP tube. Therefore, as shown in FIG. 4, the fiber 4 is cut around the hole 2a of the FRP tube 2, and there is a problem that stress concentration near the hole under load cannot be endured and cracks easily occur.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method of manufacturing a perforated hollow composite material suitable for a method of fixing a joint portion using a bolt. I am trying.

[0009]

SUMMARY OF THE INVENTION The inventor of the present invention considers that the above-mentioned problems occur because a hole is formed in a joint portion of an FRP tube after molding in the conventional method. I think that if you do it, you can solve the problem,
The following method was invented.

That is, according to the present invention, fibers impregnated with resin by a filament winding method are wound around the outer peripheral surface of a mandrel having a detachable or retractable pin at a predetermined position on the outer peripheral surface thereof, and after molding and curing, This is a method for producing a hollow composite material having a hole, the gist of which is to remove or immerse the pin from the outer peripheral surface of the mandrel.

The mandrel to be used in the method of the present invention may have various shapes depending on its application, and the tip thereof should be sharpened or hemispherical so that the filament is not caught during winding. Is desirable.

In addition, when the method of the present invention is applied, in order to prevent the inner wall of the hole from being scratched when the pin is removed or retracted after molding and curing, not only the surface of the mandrel but also the surface of the pin is prevented. Also, it is desirable to apply a release material.

[0013]

In the present invention, when the filament is wound, the winding of the fiber with the pin standing at a predetermined position on the outer peripheral surface of the mandrel is performed by another method, that is, after forming the tube,
This is because the fiber is cut in the method of drilling the bolt hole by machining, and the strength around the hole is reduced. On the other hand, if the pin is used as in the present invention, the pin having the bolt hole can be obtained by removing the pin after the hardening and molding and extracting the core, and the hole forming process for cutting the fiber becomes unnecessary.

Further, if pins are provided during filament winding, the fibers will be dense around the pins, and as a result, the fiber density will increase around the holes after the pins are removed, resulting in high strength. It is also from.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 shows an embodiment of the present invention, and is a view showing a winding state of the fibers 13 on the mandrel 11 when the pin 12 is attached to the mandrel 11 and the filament winding is performed.

In this embodiment, two places on the mandrel 11 are
That is, an example is shown in which eight pins 12 are attached to each of the ends of the FRP propeller shaft, which are located at the joints with the metal yokes, and the filament winding is performed. In addition, 14 of FIG. 1 shows a filament eye.

By the way, the pin 12 attached to the outer peripheral surface of the mandrel 11 has a screw at its base so that it can be attached to and detached from the mandrel 11. Also, pin 1
The diameter of 2 is 1-2 than the bolt connecting the shaft and the yoke.
The fiber 13 is formed to have a larger size, and the tip thereof is thin so that the fiber 13 is not caught in the middle of the pin 12 and stopped.

When filament winding is carried out in this state, as shown in FIG.
All 3 will be gathered around the pin 12, increasing the fiber density around the pin 12 and obtaining a laminated structure that is strong against stress concentration. In addition, 15 of FIG. 2 shows an FRP tube.

When the wind is finished, the mandrel 11 is removed from the apparatus and cured in the curing oven. Then pull out the pin 12 and pull out the mandrel 11 (core)
And cut both ends to obtain a FRP propeller shaft.

The state of the end portion of the FRP propeller shaft manufactured by this method is as shown in FIG.
It can be seen that the fiber is not cut at the portion a. In the present embodiment, the pin 12 has been shown to be attachable to and detachable from the mandrel 11 by using the root of the pin as a screw, but it goes without saying that the pin 12 may be retractable in the mandrel electrically or manually.

[0021]

As described above, according to the method of the present invention, it is possible to manufacture a perforated hollow composite material free from defects such as fiber breakage, and thus it is possible to obtain a product having a fiber orientation that is strong against stress concentration. ..

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method of the present invention.

FIG. 2 is a diagram showing fibers at the pores of a perforated hollow composite material produced by the method of the present invention.

FIG. 3A is a cross-sectional view of a portion where a propeller shaft and a yoke are joined by using bolts, and FIG. 3B is A- of FIG.
FIG.

FIG. 4 is a view showing fibers in a hole portion of a perforated hollow composite material manufactured by a conventional method.

[Explanation of symbols]

 11 Mandrel 12 Pin 13 Fiber

Claims (2)

[Claims] 1. A mandrel having a detachable or retractable pin at a predetermined position on the outer peripheral surface thereof is wrapped with a resin-impregnated fiber by a filament winding method, molded and cured, and then the pin is attached to the outer periphery of the mandrel. A method for producing a hollow composite material having a hole, wherein the hollow composite material is removed from the surface or immersed. 2. The method according to claim 1, wherein the perforated hollow composite material is a propeller shaft having bolt holes.