JPS6091008A - Transmission shaft made of fiber reinforced plastics - Google Patents

Abstract

PURPOSE:To enhance torsional fatigue strength of a fiber reinforced plastic (FRP) cylindrical pipe, by forming the FRP cylindrical pipe, having metallic sleeves, to be laminated so that the fiber material in its plastic may be wound at an angle of + or -25 deg.-+ or -35 deg. with respect to an axial direction of the pipe. CONSTITUTION:A fiber reinforced plastic (FRP) cylindrical pipe 1 is laminated on the periphery of a paper sleeve 2 and its both end metallic sleeves 3, 3. The metallic sleeve 3, providing on its internal surface a spline groove 3a, couples by a spline to a yoke 4 or the like. The sleeve 3, using an adhesive agent 5 to be applied onto its external surface, is adhesively mounted to the FRP cylindrical pipe 1. The cylindrical pipe 1 is formed by a fiber material so that it may be wound at an angle theta of + or -25 deg.-+ or -35 deg. with respect to an axial direction of the pipe. In this way, residual stress inside an FRP is reduced by equalizing a coefficient of thermal expansion of the FRP almost to that of metal so as to decrease tensile stress between the sleeve 3 and the cylindrical pipe 1 when they are molded to be cooled.

Description

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

Traditionally, steel shafts have been commonly used as transmission shafts for vehicles, but in recent years, lightweight, vibration-damping materials have been developed to reduce vibration and noise, as well as reduce weight and fuel consumption. The use of FRP transmission shafts with excellent characteristics is being considered. It is known that the torsional strength of a cylindrical tube made of FRP is greatest when the winding angle of the fiber body is ±45 degrees with respect to the axial direction of the cylindrical tube. Therefore, as an FRP transmission shaft,
Generally, it is considered best to wind the fibrous body at a winding angle of ±45 degrees, which has the highest torsional strength.

By the way, since the transmission shaft transmits rotational force from one end side to the other end side, it is necessary to connect other transmission parts to both ends thereof so that they can rotate together. To this end, it is necessary to provide metal parts at both ends of the FRP transmission shaft so that it can be joined by welding, bolting, or spline to other transmission parts. Such a metal part is attached by adhering to the FRP circular tube with a tube adhesive.

When bonding a circular FRP pipe tube fitting part in this way, the metal part is used as a sleeve, a thermosetting adhesive is applied to the outer surface of the sleeve, the sleeve is fitted onto a mandrel, and a thermosetting resin is impregnated on top of the sleeve. By wrapping the fibrous body and heating it, the thermosetting resin is cured to form a circular FRP tube-tube tube, and at the same time, the cylindrical tube and the metal sleeve are bonded by heating. becomes stronger and its workability is also extremely improved.

Therefore, the present inventors developed the FRP manufactured in this way.
A torsion test was conducted on the manufactured power transmission shaft. As a result, FRP
It has been found that the FRP parts adjacent to the metal sleeves at both ends of the manufactured power transmission shaft are destroyed before the central part of the cylindrical tube is destroyed. In particular, according to the data of the torsional fatigue test, it was concluded that an FRP power transmission shaft with a fibrous body wrapped at an angle of 145 degrees has a practical problem in terms of fatigue resistance, as shown in FIG. 4.

Based on these test results, the present inventors conducted research to increase the strength of the FRP in the area adjacent to the metal sleeve, and as a result, they found that by changing the winding angle of the fibers in the FRP, It has been found that the torsional strength can be increased. This is because the cause of the decrease in torsional strength is not only structural problems but also the FR of the part in contact with the metal sleeve.
This is thought to be due to residual stress inside P. F.R.
In an FRP transmission shaft manufactured by a method of bonding a metal sleeve and an FRP circular tube-tube at the same time as heating hardening of P, metal and F
Due to the difference in coefficient of thermal expansion with the HP, the portion of the FRP in contact with the metal sleeve is tensed, and the strain remains inside the FRP and acts as tensile stress in the FHP. Therefore, the torsional strength of the FRP in that portion decreases.

The present invention was made as a result of such test research, and its purpose is to provide an FRP power transmission shaft manufactured by the above-mentioned method with good workability, while improving its torsional strength and
In particular, the torsional fatigue strength should be increased to a level sufficient for use as a power transmission shaft.

In order to achieve this objective, the present invention provides a circular FRP tube in which the fibers in the FHP are laminated at a winding angle of ±25 degrees to ±35 degrees with respect to the axial direction of the cylindrical tube. I'm there.

Hereinafter, the present invention will be explained in more detail with reference to drawings and examples.

As shown in Figure 1 or Figure 2, the FRP cylindrical tube l
, a paper sleeve 2 and metal sleeves 3 at both ends thereof.
The inner diameter and the outer diameter are made to be uniform.

This FRP cylindrical tube 1 is formed by bundling several fibers, impregnating the fiber body with a thermosetting resin, and rolling it into a cylindrical shape. The method of winding the prepreg in the form of a tape or ribbon is also excellent in terms of workability, but in any case, the winding angle O of the m pyramid is in the axial direction of the FRP cylindrical tube l after forming. The angle should be between ±25 degrees and ±35 degrees. As reinforcing fibers for FRP, high-strength, high-modulus fibers such as carbon fiber, glass fiber, silicon car/dried fiber, poron fiber, and organic high-modulus fiber are used singly or in combination. However, carbon fiber is considered advantageous. The ratio of the reinforcing fiber to the thermosetting resin is 40 to 70% by volume.

The paper sleeve 2 is made of hard paper,
In addition to having uniform inner and outer diameters as shown in FIG. 1, it is also possible to have a notch 2a on the inner surface as shown in FIG. The depth of this notch 2a,
The spacing, width, etc. are selected as appropriate.

The metal sleeve 3 is provided with a spline groove 3a on its inner surface, and the yoke 4 and the like are spline-coupled by the spline groove 3a. A thermosetting adhesive 5 is applied to the outer surface of the metal sleeve 3, and a circular FRP tube is attached to the metal sleeve 3 by the adhesive 5. As this adhesive 5, an epoxy adhesive is suitable. The metal sleeve 3J includes one in which a taper is formed at the end in contact with the paper sleeve 2, extending from the center to the outer circumference, as shown in FIG. Although the example is shown as having no shape, other shapes may be used. However, when a tapered metal sleeve 3 as shown in Fig. 1 is used, when a rotational force is applied to the metal sleeve 3, F
1g of shear stress on one side of the RP circular tube tube l)
<As shown by the solid line in Figure 3, the stress applied to the FRP increases smoothly in the axial direction. Therefore, the stress distribution shown by the dotted line in FIG. 3 is obtained when the gold hIS sleeve 3 as shown in FIG. 2 is used.

FR
In terms of the lifespan of P, a tapered metal sleeve 3 as shown in FIG. 1 is advantageous.

In addition, if the inner and outer diameters of the metal sleeve 3 are made equal to the inner and outer diameters of the paper sleeve 2, the surface on which the fiber body is wound S will be flat, improving workability and heating. The integration of the FRP and the metal sleeve 3 when they are cured and bonded by heating can also be made strong. Moreover, the FRP cylindrical tube l after molding has a metal sleeve 3.
Even though the inner and outer diameters are uniform, it is possible to avoid the occurrence of extreme stress change areas due to steps, and it is possible to achieve high torsional strength.

When manufacturing such an FRP power transmission shaft, a paper sleeve 2 and a metal sleeve 3 are fitted onto a mandrel, and a fibrous body impregnated with a thermosetting resin is wound thereon at a predetermined winding angle. At this time, a thermosetting adhesive 5 is applied to the outer peripheral surface of the metal sleeve 3. Then, this is heated in a heating furnace to harden the resin and adhesive. In this way, the metal sleeve 3 and the FRP cylindrical tube l are firmly bonded together at the same time as the FRP is heated and cured.

The heating temperature and time are determined depending on the type of resin, and the heating temperature may be increased in stages as appropriate.

When curing is completed, stop heating, and after cooling, pull out the mandrel and remove the FR protruding from both ends of the metal sleeve 3.
The metal sleeve 3 and the FRP circular tubular tube 1 are bonded together and then cooled, as in the case of cutting and removing P to make a product, but the FJ'IP cylindrical tube I is The winding angle is set to ±2511[~±35 degrees with respect to the axial direction, and as a result, FRP has a coefficient of thermal expansion almost equal to that of metal, so when it is cooled, it is The tensile stress acting between the FRP circular tubular tubes 1 becomes extremely small. Therefore, the residual stress inside the FRP is reduced, and the torsional strength, especially the torsional fatigue strength, is significantly improved.

Example: A cylindrical paper sleeve with a thickness of 4.5 m+n as shown in Fig. 1 was fitted onto a metal mandrel with a diameter of 35 mm, and a tapered steel sleeve with an epoxy adhesive applied to the surface was attached to each end of the sleeve. Inserted. Carbon fiber Vesphite (pre-registration frame) ST manufactured by Toho Veslon Co., Ltd. is used as the fiber body.
-1-7'' is used to wrap 5 units at the same time on the surface of steel sleeves and paper sleeves while impregnating them with epoxy resin.The winding angle at this time is The angle was set at ±30 degrees with respect to the axial direction of the mandrel (same as the direction of the FRP circular tube tube after molding).The volume ratio of carbon fiber to epoxy resin was 60%, and the number of winding layers was 14. , the total thickness is 3.5 mm. This was heated in a heating furnace at 120°C for 3 hours, and then heated to the next step.
C'+eo'cTe 3 o'clock rfJI heating was performed to harden and mold the FRP, and the joining of the steel sleeve to the FRP was completed.

After natural cooling, the mandrel was removed, and the FRP protruding from both ends of the steel sleeve was cut and removed to obtain a product. The total length of the product was 272 am.

Same as the above example <FRP thickness 3.5cm #! 1! a
The one where only the winding angle of t was changed and the thickness of FRP was changed to 2
．． Table 1 shows the results of torsional fatigue data obtained for the fiber wrapping angles of 5.5 and 5.5. Figure 4 shows this in graph form.

lJ 1- No. 9 -- n=1 Conditions: ±80kg-m double swing, 2Hz to 4Hz As is clear from Table 1 and Figure 4, winding angle ±25 degrees to ±
The 35 degree angle is significantly superior to other types in terms of torsional fatigue strength. In other words, the lifespan against fracture at the joint between the steel sleeve and FRP is longer when the FRP thickness is 2.5 mm than when the winding angle is ±45 degrees.
(1) is also about 10 times larger for Note, and about 100 times larger for FRP with a thickness of 3.5 mm.

In this way, if the winding angle of the fiber body is ±30 (±5) degrees, the number of repetitions Nf until breakage will be approximately 106 or more, and even with safety in mind, it will be sufficiently practical as a power transmission shaft. In addition, it was confirmed that with this winding angle, not only the dynamic torsional fatigue strength was improved, but also the static oscillation torsional strength was improved.

As is clear from the above description, the present invention is lightweight, has excellent absorption characteristics such as gear noise and whining noise from the transmission, noise from tires, etc., and vibration reduction characteristics, and has excellent torsional strength, especially torsional strength. FRP transmission shaft with high fatigue strength,
It can be obtained by a manufacturing method with good workability.

[Brief explanation of the drawing]

Fig. 1 is a cutaway front view showing one embodiment of an FRP power transmission shaft according to the present invention, Fig. 2 is a cutaway front view showing another embodiment, and Fig. 3 is a diagram showing the shape and shape of a metal sleeve. An explanatory diagram showing the correspondence relationship with the stress component 1 (i) on the upper surface of the cylindrical tube. FIG. 4 is a graph showing the test results of the relationship between the winding angle of the fibrous body and the torsional fatigue strength. 1... Made of FRP Circular pipe tube 2...Paper sleeve 3.
...Metal sleeve 5...Adhesive applicant Honda Motor Co., Ltd. applicant Yokohama Rubber Co., Ltd. agent Patent attorney Yu Morishita Hajime

Claims (1)

[Claims] A cylindrical tube made of fiber-reinforced plastic formed by winding a fiber body impregnated with resin, and an adhesive applied to the outer surface of the cylindrical tube, which is placed inside both ends of the cylindrical tube, allows the fibers to be bonded. a metal sleeve that is heat-bonded to the cylindrical tube during thermoforming of the reinforced plastic cylindrical tube, and the fiber body in the fiber-reinforced plastic is tilted at an angle of ±25 degrees to ±± with respect to one direction of the cylindrical tube. A transmission shaft made of fiber-reinforced plastic, characterized by being laminated to form a winding angle of 35 degrees.