JPS6071231A - Manufacture of transmission shaft made of fiber- reinforced plastic - Google Patents

Abstract

PURPOSE:To manufacture a lightweight transmission shaft made of FRP having excellent nature such as high twist strength with a high workability by inserting a paper sleeve light and inexpensive between a metal mandrel and the FRP. CONSTITUTION:A cylindrical paper sleeve 2 is fitted into a mandrel 1 and a metal sleeve 3 coated with an epoxy.nitryl based adhesive 4 on the surface thereof is fitted into both ends thereof. Then, a continuous fiber body 5 obtained by impregnating a carbon fiber material with an epoxy resin is wound on the surfaces of the cylindrical paper sleeve 2 and the metal sleeve 3. The work is hardened by heat in a heating furnace and after it is cooled, the mandrel 1 is pulled off. Then, FRP extruded at both ends of the metal sleeve 3 is cut away to obtain the desired product.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a transmission shaft made of fiber reinforced plastic (hereinafter abbreviated as FRP) suitable for a drive shaft of a small and lightweight vehicle such as a front engine front wheel drive vehicle. be.

In the past, steel transmission shafts were generally used for vehicles, but in recent years, lightweight and vibration-damping materials have been developed to reduce vibration and noise, as well as to reduce weight and fuel consumption. The use of FRP transmission shafts with excellent characteristics is being considered. And this kind of FRP
Various proposals have been made in the past to increase the torsional strength of manufactured power transmission shafts. For example, JP-A-53-71423 discloses a structure in which FRP and a metal material are laminated so that the characteristics of the metal material are added to the FRP.

Furthermore, Japanese Patent Application Laid-Open No. 53-73731 discloses a composite structure in which FRP and rubber or thermoplastic resin are laminated. However - such laminates are F
Since it is heavier than RP, a transmission shaft made of FRP made of laminated materials inevitably becomes heavier. Also,
When rubber or thermoplastic resin is used as a laminated material, F
When heated to cure RP, the laminate may become deformed.

The present inventors have been researching the torsional strength of FRP power transmission shafts, and as a result, they have found that one of the causes of the reduction in the torsional strength of FRP power transmission shafts is a problem with the manufacturing method. In other words, generally FRP transmission shafts are
It is produced by wrapping a continuous fiber impregnated with resin around a metal mandrel, heating and hardening it in a heating furnace, and extracting it from the mandrel after cooling. Therefore, when the heat curing is completed in the heating furnace and the product is cooled,
The difference in thermal expansion coefficient between FRP and metal mandrel generates tensile stress between them, which remains as residual stress inside the FRP layer. This residual stress is one of the reasons for the decrease in torsional strength.

The present invention was made as a result of such research, and its main purpose is to reduce the residual stress remaining in the FRP layer and to reduce the residual stress that remains in the FRP layer, and to reduce the amount of stress remaining in the FRP layer, and to reduce the amount of stress remaining in the FRP layer, thereby making it possible to produce an FRP transmission shaft that is lightweight and has high torsional strength. The purpose is to provide a method.

In addition, the present invention provides an F that is low cost and has excellent workability.
Another object of the present invention is to provide a method for manufacturing a power transmission shaft made of RP.

In order to achieve these objectives, in the present invention, prior to winding a continuous mist body impregnated with resin around a mandrel, a paper sleeve is fitted onto the mandrel, a fibrous body is wound thereon, and the fiber body is heated in a heating furnace. I'm trying to harden it.

In this method, the paper sleeve fitted into the mandrel serves as a buffer that absorbs the difference in thermal expansion coefficient between the metal mandrel and the FRP. Such buffers are required to have the following properties: ■ Light weight and low cost; ■ Resistance to thermal deformation; ■ Capable of absorbing external stress; ■ Not damaging the mandrel; ■ Good workability. However, paper sleeves can be said to be the most suitable material that satisfies these requirements.

Next, the present invention will be explained in more detail using the drawings.

First, a paper sleeve 2 is fitted onto a metal mandrel l. This paper sleeve 2 is made of hard paper and has uniform inner and outer diameters as shown in FIG. In addition, there is a notch 2a on the inner surface as shown in Figure 2.
Those having the following can also be used. This notch 2
The depth, spacing, width, etc. of a can be selected as appropriate.

Usually, metal sleeves 3 are arranged on both sides of this paper sleeve 2. This metal sleeve 3 is provided with a spline groove 3a on its inner surface, and rotation is transmitted by fitting a spline shaft into the spline groove 3a.

In addition to steel, aluminum alloy, titanium alloy, etc. can be used for the metal sleeve 3, thereby further reducing the weight of the entire power transmission shaft. Furthermore, a thermosetting adhesive 4 is applied to the outer surface of the metal sleeve 3. As a result, the FRP layer 5 and the metal sleeve 3 are bonded together at the same time as the FRP layer 5 is heated and hardened, which improves the efficiency of one operation. As the thermosetting adhesive 4 applied to the outer surface of the metal sleeve 3, an epoxy adhesive whose main component is epoxy, nitrile resin, or the like is suitable. Furthermore, by making the thickness of the paper sleeve 2 and the metal sleeve 3 the same, winding of the fiber body becomes easy and desirable results can be obtained in terms of strength.

As reinforcing fibers for FRP, fibers with high strength and high elastic modulus such as carbon fibers, glass fibers, silicon carbide m-fibers, and poron fibers are used alone or in combination, and carbon fibers are considered to be particularly advantageous. The continuous fiber body of the present invention is
Although several fibers are bundled and wrapped with resin while being impregnated with it, it goes without saying that a method of wrapping prepreg in the form of a tape or ribbon is also superior in terms of workability. As the resin to be impregnated into the continuous fiber body, thermosetting resins such as epoxy resins, phenol resins, polyester resins, and polyimide resins are used. The ratio of the continuous fiber body and the resin impregnated therein is usually 4:6 to 7: carbon fiber 1III: eboshiki resin in terms of volume ratio.
Although it is within the range of about 3, it is not limited to this range.

In this way, after the continuous fiber body impregnated with resin is wound around the upper surface of the paper sleeve 2 to form the FRP layer 5, the FRP layer 5 is placed in a heating furnace and heated and hardened by a conventional method. The bonding between the metal sleeve 3 and the FRP layer 5 is completed by the thermosetting adhesive 4 applied to the outer surface of the metal sleeve 3 when the FRP is heated and cured. The heating temperature and time are determined depending on the type of resin, but it is desirable to start curing at a relatively low temperature and increase the curing temperature in two or three stages.

When curing is completed, the heating is stopped, and after cooling, the mandrel l is removed and the FR protruding from both ends of the metal sleeve 3 is removed.
The P layer 5 is cut and removed to obtain a product.

According to this method, compared to a method in which resin-impregnated fibers are directly wound on the surface of a metal mandrel and cured by heating, no residual stress is generated inside the FRP layer, so the torsional strength of the transmission shaft can be improved. The FRP transmission shaft obtained by this method is extremely lightweight as a whole, and has excellent absorption characteristics of gear noise and whining noise from the transmission, noise from tires, etc. Furthermore, due to the presence of both the FRP and paper three layers, the vibration reduction effect is better than that of FRi alone. Also, F.R.
The residual stress inside FRP is smaller than that in which P is laminated with metal.

In particular, if metal sleeves are placed at both ends of the paper sleeve as described above, the resin-impregnated fiber body can be wrapped without any steps, and the metal sleeve can be assembled onto the transmission shaft without any steps. You will be able to do this. Further, by applying a thermosetting adhesive to the outer surface of the metal sleeve, the FRP layer and the metal sleeve can be bonded together at the same time as the FRP is cured. Therefore, after hardening and forming FRP into a cylindrical shape,
Compared to the method of gluing metal sleeves, metal yokes, etc. on both ends with adhesive, this method not only makes the bond stronger, but also has superior workability and can be expected to reduce costs. Become something.

An example of this method will be described below.

Example l On a mandrel with a diameter of 35II+1, the first layer with a thickness of 4.5H
A cylindrical paper sleeve as shown in the figure was fitted, and a metal sleeve whose surface was coated with an epoxy-nitrile adhesive manufactured by American Cyanamid was fitted into both ends of the sleeve. Carbon fiber "Besphite (registered trademark) ST-1-7" manufactured by Toho Bethlon Co., Ltd. was used as the continuous fiber body, and 5 units of 6000 fibers were simultaneously impregnated with epoxy resin and made into metal sleeves and paper sleeves. wrapped around the surface of. At that time, the capacity ratio of carbon fiber to epoxy resin was 60%, the number of winding layers was 14, and the total thickness was 3.5%.
■It was. This was heated in a heating furnace at 120°C for 3 hours and then at IeO'C for 3 hours to harden it. After curing, it was cooled, the mantle was removed, and the FRP protruding from both ends of the metal sleeve was removed. The product was cut and removed. The total length of the product is 272cm.

As shown in FIG. 1, the end of the metal sleeve on the paper sleeve side is tapered from the center toward the outer circumference. This taper allows the stress generated in the FRP to increase smoothly in the axial direction when a torsional force is applied to the metal sleeve, thereby helping to disperse stress concentration. The taper also serves to smoothly reduce residual stress in the FRP layer after thermosetting due to the difference in thermal expansion coefficient between the metal sleeve and the FRP in the axial direction.

Flow Example 2 An FRP power transmission shaft was manufactured under the same conditions as in Example 1, except that a paper sleeve having the shape shown in FIG. 2 was used. By providing a notch on the inner surface of the paper sleeve, we were able to further reduce the overall weight.

As is clear from the above description, according to the present invention, an FRP transmission shaft that is lightweight, has high torsional strength, and has excellent noise absorption characteristics and vibration reduction characteristics can be manufactured by a method with excellent workability. be able to.

[Brief explanation of drawings]

Fig. 1 is a cutaway front view showing the state in one step for explaining the method of manufacturing an FRP power transmission shaft according to the present invention, and Fig. 2 is Fig. 1 showing an example using a different paper sleeve. It is a notch front view similar to. l...Mandrel 2...Paper sleeve 3...Metal sleeve 4...Adhesive 5...FRP layer Applicant Ichi Honda Motor Co., Ltd. Agent Patent attorney Yu Morishita Hajime

Claims (1)

[Claims] A paper sleeve is fitted into a mandrel, and a resin-impregnated continuous fiber body is wound around the mandrel to form a fiber-reinforced plastic layer, which is then heated in a heating furnace to A method for producing a power transmission shaft made of fiber-reinforced plastic, characterized in that the fiber-reinforced plastic layer is hardened, cooled, and then extracted from the mandrel.