JPS6382728A - Manufacture of fiber-reinforced resin pipe with metallic coupling - Google Patents

Abstract

PURPOSE:To improve productivity drastically while enabling strong adhesion between fiber-reinforced resin pipe and a metallic coupling, by a method wherein the metallic coupling is inserted into an expanded pipe end by interposing an adhesive agent and then the adhesive agent is cured at a temperature lower than a heating, expanding and operating temperature. CONSTITUTION:A metallic coupling 2 whose outside diameter is made into about the same size as the inside diameter of a fiber-reinforced resin pipe 1 is manufactured separately, to the surface of which an adhesive agent 3 is applied. After prepreparation like this, a pipe end of the above-mentioned fiber-reinforced resin pipe 1 is expanded in a diametral direction. The metallic coupling 2 is inserted into the pipe end whose diameter has been expanded and then cure of the adhesive agent 3 is performed by heating the same at a temperature lower than a heating, expanding and operation temperature by keeping the same as it is. It follows that the metallic coupling 2 is tightened up by the fiber-reinforced resin pipe 1 and the adhesive agent 3 displays strong joining force through its tightening action as the fiber-reinforced resin pipe 1 is contracted in the diametral direction, in heating and curing treatment of the adhesive agent 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of manufacturing a fiber-reinforced resin pipe with a metal joint used for a power transmission shaft of a vehicle or the like.

[Prior art]

In order to reduce the weight of vehicles, attempts are being made to apply fiber-reinforced resin products to various parts. Among these, when used as a power transmission shaft, a structure in which fiber-reinforced resin is formed into a tube and a metal joint is connected to the end of the tube is used.

For fiber-reinforced resin pipes with metal joints used in such power transmission shafts, it is necessary to firmly connect the fiber-reinforced resin pipe and metal joint so that they do not easily separate due to the transmission torque. It has become an important issue.

Therefore, when manufacturing fiber-reinforced resin pipes with metal joints, it is effective to tightly wrap the fibers around the outer periphery of the metal joint when gluing the metal joint to the end of the fiber-reinforced resin pipe while inserting it. has been done.

FIG. 6 explains the conventional manufacturing method of such a fiber-reinforced resin pipe with a metal joint. First, a long spacer 16 and a short spacer 17 made of a paper tube or the like are placed on a mandrel 15.
and the metal joints 12 are fitted alternately. The long spacer 16 is used to regulate the distance between the metal joints 12.12 and to form a surface that is flush with the metal joint 12, and the short spacer 17 is used to control the spacing between the metal joints 12. ) Fiber reinforced resin pipe aI with metal joint,
a8. It is provided as a cutting margin when separating into a.

Adhesive is applied to the outer circumferential surfaces of the metal joint 12 and spacers 16 and 17 that are continuously assembled on the mandrel 15 in this way, and reinforcing fibers such as filament-like carbon fibers impregnated with uncured resin are spirally applied thereon. The fiber-reinforced resin pipe 11 is formed by repeatedly winding the fiber into a shape. Thereafter, the fiber-reinforced resin pipe 11 is heated to partially cure the fiber-reinforced resin pipe and the adhesive at the same time (generally known as co-cure).
re) law]. Next), cut at the spacer 17 part and attach multiple fiber-reinforced resin pipes with metal joints.
+”!+23.

In addition, when attaching a connecting means such as a yoke to the metal joint 12, the spacer 17 is removed as described above, and the end of the metal joint 12 is exposed.
The connecting means is attached to the exposed portion by welding or the like.

However, according to the above-mentioned conventional manufacturing method, when heating and curing the fiber-reinforced resin pipe 11, heat conduction is different between the metal joint 12 and the spacer 16, 17, so it cannot be cured in the same way. However, there is a disadvantage that the yield of products increases and productivity decreases. In addition, since the spacer 17 is cut, part of the fiber reinforced resin becomes waste and is thrown away, which increases the cost.Also, the spacer 16 remains inside. Therefore, there is a disadvantage that it cannot help but be disadvantageous for the purpose of weight reduction.

[Purpose of the invention]

An object of the present invention is to provide a fiber-reinforced resin pipe with a metal joint that can significantly improve productivity while solving the problems of the prior art described above and enabling strong adhesion between the fiber-reinforced resin pipe and the metal joint. The purpose is to provide a manufacturing method.

[Structure of the invention]

To achieve the above object, the present invention provides a method for manufacturing a fiber-reinforced resin pipe in which a metal joint is connected to the end thereof. The tube is heated and expanded to a diameter larger than the diameter of the hand joint, the metal joint is inserted into the expanded tube end with an adhesive interposed therebetween, and the adhesive is then cured at a temperature lower than the heating and expansion operation temperature. It is characterized by the following.

In the present invention, any fibers conventionally used as reinforcing fibers can be used as the fibers used for the fiber-reinforced resin pipe, especially carbon fibers.

Examples include glass fiber, aramid fiber, boron fiber, and carbonized carbide fiber. These reinforcing fibers may be used alone or as a hybrid in combination with other fibers. Further, as the resin used for the fiber-reinforced resin pipe of the present invention, a thermosetting resin is preferable,
Epoxy, unsaturated polyester, vinyl ester, etc. can be mentioned.

Furthermore, the adhesive used in the present invention is preferably a thermosetting resin type adhesive, such as an epoxy type adhesive.

Unsaturated polyester-based and vinyl ester-based materials are preferred.

In the present invention, when preforming a fiber-reinforced resin pipe, the fibers mixed in the fiber-reinforced resin may be in the form of continuous filaments (long fibers) or short fibers cut into short lengths. However, especially in the case of fiber-reinforced resin tubes used for power transmission shafts, it is better to use continuous filament tubes.

In order to form a fiber-reinforced resin tube from such filament-like fibers, especially for use in power transmission shafts, it is best to use the well-known filament winding method.
In other words, there is a method in which filament-shaped reinforcing fibers are impregnated with uncured resin and wound around a rotating mandrel at a predetermined winding angle, or prepreg is made by impregnating filament-shaped reinforcing fibers with uncured resin. This method involves wrapping the prepreg at a predetermined angle while rotating a mandrel. By winding the filamentary fibers on the mandrel in this manner, a fiber-reinforced resin tube wound in a twill pattern can be obtained.

The mandrel used at this time should have a diameter that is equal to the outer diameter of the joint of the metal joint that will be connected later, so that the inner diameter of the fiber-reinforced resin pipe is different from the outer diameter of the joint of the metal joint. can be the same size.

As mentioned above, the fiber-reinforced resin tube that is formed by being wrapped around a mandrel is heated as it is to cure the resin and then removed from the mandrel, but at this time the resin is not completely cured. It is also possible to leave the mold in a fully cured or incompletely cured state. It is more preferable to demold in the latter incompletely cured state. This not only facilitates demolding from the mantle, but also allows metal joints to be made When adhering to a material, the adhesive force can be further strengthened. However, regardless of whether it is completely cured or incompletely cured, since the curing process is performed on a single mandrel, the way the heat is transmitted to the fiber-reinforced resin tube is uniform throughout, resulting in a homogeneous product with a high yield. A fiber-reinforced resin pipe can be obtained.

The fiber-reinforced resin tube formed as described above is then cut into a predetermined length according to the intended use, such as a power transmission shaft, and separated into a plurality of fiber-reinforced resin tubes.

In order to improve adhesiveness of the fiber-reinforced resin pipes separated into predetermined lengths, it is desirable to pre-treat the adhesive surface on the inner surface of the pipe end with a puff treatment or a brimer treatment. In this case, In the case of a fiber-reinforced resin pipe in which the resin is completely cured, it is preferable to perform pretreatment to improve adhesiveness by plasma treatment.

On the other hand, in addition to such pretreatment for the fiber-reinforced resin pipe, the surfaces of the metal joints to be connected thereto are also pretreated for adhesion, and an adhesive is applied in advance. As an adhesive at this time, carving and adhesive may be applied alone, but
It is convenient to use it in the form of a so-called carrier-containing sheet adhesive. In other words, a carrier-containing sheet adhesive uses a mesh-like fabric such as a coarse woven fabric as a carrier;
It is impregnated with adhesive, and when used as an adhesive, it not only facilitates the application operation and improves workability, but also ensures a uniform adhesive thickness because it does not flow out during curing. This is because it is possible to secure stronger adhesive strength.

In the present invention, when connecting a metal joint prepared as described above and a fiber-reinforced resin pipe, the fiber-reinforced resin pipe is heated and expanded, and at least the inner diameter of the pipe end is made of metal coated with an adhesive. Make it larger than the outside diameter of the connecting part of the joint. Insert the metal joint with the adhesive material into the end of the expanded fiber-reinforced resin pipe, and heat it in that state at a temperature lower than the heating expansion temperature to prevent the adhesive from curing and to prevent any imperfections. In the case of a cured fiber reinforced resin pipe, the resin is cured. During the heat curing process of this adhesive, the fiber-reinforced resin tube contracts in the radial direction, so
A tightening action occurs on the surface of the metal joint. Therefore, the adhesive is constantly tightened while curing, which results in an extremely strong adhesive force.

In the case of a fiber-reinforced resin pipe formed by filament winding as described above, the circumferential direction (therefore proportional to the radial direction)
It is observed that the degree of thermal expansion (coefficient of thermal expansion) of is different depending on the winding angle θ of the filament. That is, the fourth
As shown in the figure, if the winding angle with respect to the axial direction of the filament F in the fiber-reinforced resin pipe 1 is θ, then as shown in the graph of FIG. 5, when the filament is carbon fiber, it changes like a curve C. As a result of experiments, it was observed that in the case of glass fibers, the curve G changes, and in the case of aramid fibers, the curve A changes.

On the other hand, the coefficient of thermal expansion of steel is 10~llXl0-
#'/'C. Therefore, when the metal joint is made of steel, in order to heat-expand the fiber-reinforced resin pipe according to the present invention, the winding angle θ of the filament must be larger than the coefficient of thermal expansion of the steel. It is necessary to select a wrap angle in a region that provides the coefficient of thermal expansion. In other words, in the case of carbon fiber/epoxy resin, set the thermal expansion coefficient of steel to the lower limit of 10XIO.
-'/℃, it is around 0 x 1 θ 1 x 306, and in the case of glass fiber/epoxy resin, it is 0 x)
θ1 is around 35°, and in the case of aramid fiber/epoxy resin, it is around 0x1θl<41''.

Regarding the relationship between the winding angle θ and the coefficient of thermal expansion, the required winding angle can be found in the same manner as described above even in the case of a hybrid fiber-reinforced resin pipe in which two or more types of reinforcing fibers are combined.

The figure is an explanatory diagram showing a specific example of the manufacturing method of the present invention.

In the examples shown in FIGS. 1A and 1B, a fiber-reinforced resin pipe 1 that has been previously formed and cut into a predetermined length as shown in FIG. 1A is prepared. The inner surface of the end of the fiber-reinforced resin tube 1 is subjected to puff treatment or plasma treatment as a pretreatment to improve adhesiveness.

On the other hand, a metal joint 2 having the same outer diameter as the inner diameter of the fiber-reinforced resin pipe 1 is separately produced, and an adhesive 3 is applied to its surface.

After such preliminary preparation, the end of the fiber-reinforced resin pipe 1 is expanded in the radial direction by heat treatment, the metal joint 2 is inserted into the diameter-expanded end, and then the temperature of the heating expansion operation is increased as it is. Adhesive 3 (and its resin in the case of incompletely cured fiber-reinforced resin pipes) by heating at a lower temperature.
Curing is performed.

During the heat curing process of the adhesive 3, the fiber-reinforced resin pipe 1 contracts in the radial direction, so the fiber-reinforced resin pipe 1 tightens the metal joint 2, and the tightening action causes the adhesive 3 to exert a strong bonding force. It becomes like this.

In the case of FIGS. 1A and B, the metal joint 2 has an open end shape, but as in the example shown in FIGS. 2A and B, the yoke 2
The present invention can be carried out in the same manner by using a metal joint 2 of a closed end type in which a is integrally formed. However, when using this end-closed metal joint 2, it is necessary to provide an air vent hole 4 at the end thereof.

In addition, in the case of this end-closed metal joint 2, Fig. 3A and B
It is preferable to use one provided with a flange-like protrusion 5 as shown in , C. By providing this protrusion 5, when inserting the metal joint 2, it is only necessary to insert it until the protrusion 5 and the end face of the fiber-reinforced resin pipe 1 come into contact, so that the position relative to the fiber-reinforced resin pipe 1 can be accurately It is possible to obtain products with extremely high dimensional accuracy.

Furthermore, the fiber-reinforced resin pipe does not necessarily have to have the same diameter in the entire longitudinal direction as shown in Fig. 1A, B, etc.;
, B may be a stepped fiber-reinforced resin pipe 1 in which the diameter is different between the part to which the metal joint is bonded and the other part.

〔Example〕

While impregnating the carbon fiber filament with uncured epoxy resin, the outer diameter of the carbon fiber filament is 4.
After winding a 6.20mm mandrel with a winding angle of ±30@ and a winding thickness of 14mm, this was heat-cured at 120°C for 40 minutes, resulting in an outer diameter of 5mm with the resin incompletely cured.
A fiber-reinforced resin pipe with a length of 3 m+* and an inner diameter of 46.20 mm was obtained.

This fiber-reinforced resin pipe was cut and separated into lengths of 2,001 mm to obtain straight fiber-reinforced resin pipes as shown in Figure 1A and B, and then the adhesive surfaces on the inner surfaces of both ends of one of the pipes were puffed. , Primer treatment was performed.

On the other hand, after blasting and primer treatment were applied to the adhesion surface of a separately produced metal joint as shown in FIGS. 1A and 1B, a carrier-containing sheet of epoxy adhesive was applied. The outer diameter including this adhesive is 46.4On+m,
The length was 50fflT1.

Next, the fiber-reinforced resin tube was heated in a heating oven for 200 minutes.
A heat treatment was performed for .degree. After inserting the metal joint, it was heated and cured for 160'c x 5 hours to cure the adhesive and the resin in the partially cured fiber-reinforced resin pipe, then it was removed from the heating oven and slowly cooled to room temperature. A final fiber-reinforced resin pipe with metal joints was obtained as a product.

The above fiber reinforced resin pipe with metal joint is used as a power transmission shaft,
Torsional fatigue was applied 1 million times under the condition of applying a torque of ±100 kg-n+ (double swing), but no peeling of the adhesive surface occurred at all, and the fatigue level was similar to that explained in the prior art section.・It was comparable to adhesion using the cure method.

〔Effect of the invention〕

As mentioned above, the manufacturing method of the present invention involves forming a fiber-reinforced resin pipe in advance and connecting it to a separately manufactured metal joint. There is no waste caused by cutting and removing.
In addition, since uneven heat conduction is not imparted to the fiber-reinforced resin tube during heat curing, resulting in no uneven quality, productivity can be significantly improved.

Furthermore, when bonding, the metal joint is inserted into a fiber-reinforced resin tube whose diameter has been heated and expanded through an adhesive, and the adhesive is cured at a temperature lower than the operating temperature of the heating expansion, so that the adhesive is bonded to the fibers. It hardens while being subjected to the tightening pressure caused by the contraction of the reinforcing resin tube, which results in extremely strong adhesive strength.

[Brief explanation of the drawing]

Figures 1A and B are explanatory views showing the manufacturing method according to the present invention; Figures 2A and B; Figures 3A, B, and C1; Figures 4A and B are explanatory views showing methods according to other embodiments, respectively. , Fig. 5 is an explanatory diagram explaining the winding angle θ of fibers in a fiber reinforced resin pipe, Fig. 6 is a graph showing the relationship between the coefficient of thermal expansion of a fiber reinforced resin pipe and the winding angle θ, and Fig. 7 is a conventional diagram. FIG. 2 is an explanatory diagram showing a manufacturing method. 1...Fiber reinforced resin pipe, 2...Metal joint, 3...
··glue.

Claims (4)

[Claims] (1) In a method for manufacturing a fiber-reinforced resin pipe with a metal joint connected to the end, a pre-formed fiber-reinforced resin pipe is heated and expanded to a diameter larger than the diameter of the connection part of the metal joint, and the expanded pipe end A method for manufacturing a fiber-reinforced resin pipe with a metal joint, comprising: inserting the metal joint with an adhesive interposed therein, and then curing the adhesive at a temperature lower than the heating and expansion operation temperature. (2) The method for manufacturing a fiber reinforced resin pipe with a metal joint according to claim 1, wherein the fiber reinforced resin pipe is formed by filament winding. (3) The method for manufacturing a fiber-reinforced resin pipe with a metal joint according to claim 1, wherein a fiber-reinforced resin pipe in which the resin is incompletely cured is molded, and the fiber-reinforced resin pipe is heated and expanded. (4) A fiber-reinforced resin pipe with a metal joint according to claim 1, wherein the metal joint side is coated with a carrier-containing sheet adhesive in advance, and the metal joint is inserted into the pipe end of the fiber-reinforced resin pipe. Production method.