DE2852033C2 - - Google Patents

Description

The invention relates to a shaft for transmitting rotation moments and bending forces according to the generic term of the patent saying 1.

For a shaft for the transmission of torques and bending forces according to the preamble of claim 1 as they is known from DE-OS 20 58 016, are on a thorn that is wrapped with a protective layer, a first intermediate layer of high modulus fibers at an angle of about 45 ° to the mandrel axis, and a second intermediate layer of fibers with high modulus, which are under an equal size a small but opposite angle to the mandrel axis, wrapped. This structure comes with an outer protective layer wrapped and then cured in a mold. The well-known Although the shaft is lightweight, it is used to transmit high forces and torques, however, only suitable to a limited extent and leaves none high rotational speeds.

The invention has for its object a lightweight Wave of the type according to the preamble of claim 1 so train that despite different thermal physical Properties, e.g. B. different thermal expansion coefficients, for the metal core on the one hand and the fiber strong plastic coating on the other hand, is suitable, high Take up forces or moments and high rotational speed permit.

This object is achieved by the features of characterizing part of claim 1 solved.  

Most of the torque is from the metal core taken. The metal core and the fiber-reinforced plastic sheathing form a composite, in which the reinforcing fibers due to their orientation at a certain angle to the Longitudinal axis the differences in the physical properties compensate for the plastic coating and the metal core, ins special the difference in the thermal expansion coefficient targeted. Due to the larger diameter of the shaft in her middle range is particularly high for transmission Suitable for torsion and bending forces.

Preferred embodiments of the invention are the subject of Subclaims.

Exemplary embodiments of the invention are described below the drawing explained. It shows

Figure 1 is a partially cut, perspective Dar position of the assignment of the alternately applied layers to the metal core.

Fig. 2 in top view, the shape of the blank of the layers for the plastic enclosure;

Fig. 3 is a plan view of another form of layers of the plastic covering;

. Figure 4 is a further plan view of another form of the blank of the layers for the plastic enclosure;

Fig. 5 is a vertical section through the layers along the section line 5-5 of Fig. 2 and

Figure 6 is a perspective view of the wave, which is partially cutaway., Showing the fibers in the layers,

The shaft has a metal core 25 in the form of a cylindrical, hollow tube, as shown in Fig. 1. So that the shaft has the desired strength with a low weight, the metal core 25 is preferably made of aluminum or magnesium alloys. The following aluminum alloys are preferably used for the production of the metal core 25 : 2024, 7075, 7078 and 6061, these specifications being American alloy composition data. These alloys preferably have a T-6 age hardening. Aluminum alloys with the above-mentioned compositions and the above-mentioned hardness are commercially available and can be formed into tubes by conventional methods, which are formed by drawing or extruding thick-walled, cylindrical elements according to the required dimensions.

When manufacturing the shaft, it is important that the metal core 25 is completely clean. In order to avoid any possible surface contamination, the final cleaning of the metal core 25 is carried out with an agent such as alcohol or chlorofluorocarbon in order to remove traces of oil, grease etc.

The metal core 25 is surrounded by a sheath of resin-impregnated, directed graphite reinforcing continuous fibers 20, 22 and of glass fiber fabric, which are connected to the core 25 , so that a substantially one-piece component is formed. This covering made of fiber-reinforced plastic consists of individual layers. The two layers of fiber-reinforced plastic are finally bonded together by allowing the resin contained therein to harden.

In the manufacture of the shaft, a number of layers are initially put together, which are essentially the same shape. Thus, a layer, such as layer 26, is cut from a surface of a material reinforced with directional fibers. The reinforcing fibers are preferably made of carbon or graphite, and for the sake of simplicity these endless fibers are referred to below as reinforcing or graphite fibers. The layer 26 has a specific shape, the length of which is preferably somewhat greater than the axial length of the fiber-reinforced sheathing of the shaft. The reason for this oversize is a relief in the manufacture, which will become clear after the following. As is apparent from FIGS. 1 and 2, the preferred geometric shape 10 is triangular for the layers essentially are, where provided in end flaps 30 and 32 which extend from the base of the triangle to the outside. The width of the end flaps 30 and 32 is approximately twice the circumference of the tubular core 25 , so that the layers can be wrapped around the core 25 essentially twice. The width of the impregnated layers, measured from the tip of the triangle to the base line, should be sufficient so that the layer can be placed several times around the circumference of the metal core 25 . Preferably, the width of the impregnated layers is approximately six times the circumference of the metal core 25 .

As shown in FIGS. 3 and 4 show other forms, in the preparation of the layers together, and finally the amount of translated shaft can be used. Each layer can be cut out in the desired pattern or patterns by combining different geometric shapes. Thus, the shape 10 according to FIG. 2 has been created by putting together rectangular and triangular shapes which are alternately cut out and arranged. The shape 11 according to FIG. 3 is obtained by placing several rectangles next to one another, each subsequent rectangle being somewhat shorter than the previous rectangle. You get, for example, the shape 12 of FIG. 4 by putting together a trapezoid and a rectangle.

The resin material with which the graphite fibers 22 of the layer 26 are impregnated is a thermosetting resin. Basically the resin of all resin impregnated layers is thermosetting. Suitable thermosetting resins are, for example, epoxy and polyester resins.

The epoxy resins or polyepoxides, which are well known condensation products are Compounds containing oxirane rings with verbin with hydroxyl groups or active water atoms of matter, such as amines and aldehydes. The usual epoxy Resin compounds are those of epichlorohydrin and Bisphenols and their homologues.

The polyester resin is a condensation product made up of more basic acids with polyhydric alcohols. Typical poly esters include polyterephthalates such as polyethylene terephthalate.

These thermosetting resins can be additives such as hardeners and contain similar. The preferred, with modified Epoxy resin impregnated graphite fibers are commercially available available. For example, those pre-impregnated with epoxy Graphite fibers under the names Rigidite 5209 and Rigidite 5213, manufactured by the Narmco Division of Celasnese Cor poration, New York, V. St. A., distributed. Other reference Sources for the graphite fibers pre-impregnated with resin are the Industry known.

Generally, the resin impregnated layer 26 has a thickness of about 0.178 mm to about 0.254 mm and contains from about 50% to about 60% by volume of graphite fibers in the thermosetting resin. Layer 26 preferably contains 54% to 58% by volume of continuous rectified graphite fibers in the epoxy resin. The graphite fibers preferably have a Young's modulus of elasticity in the range from 2.11 × 10 ⁶ to 3.52 × 10 ⁶ kg / cm ² and a tensile strength in the range from approximately 14,085 kg / cm ² to approximately 20 169 kg / cm ² .

As shown in the drawings, layers 24 and 27 of glass fabric are also provided. The layers 24 and 27 have the same dimensions and geometric shapes as the resin-impregnated, fiber-reinforced layer 26 . Layers 24 and 27 have a thickness of about 0.0254 to about 0.0508 mm and are made of glass fiber fabric, which is a cloth-like fabric known as glass yarn scrim. Glass yarn scrim Style 107, sold by Bulington Glass Fabrics Company, New York, V. St. A., is particularly preferred. The glass fibers 21 of the scrim are at an angle of 0 ° and 90 ° on the longitudinal axis of layers 24 and 27 aligned.

As can be seen from the detail in FIG. 1, the directed graphite fibers 20 in the layer 28 are oriented at an angle R ₁ to the longitudinal axis of the layer 28 . In the next layer of resin-impregnated directional continuous graphite fibers, namely in layer 26 , the directional graphite fibers 22 are oriented at a negative angle R ₂ to the longitudinal axis of layer 26 . This angle is preferably the same size and of course an opposite sign to the orientation of the fibers in the first layer.

In the manufacture of the shaft, a plurality of layers of resin-impregnated, endless graphite fibers and glass fabric are cut out of a laminate in the desired flat shape. Each layer is the same size and shape. As already mentioned, the end flaps 30 and 32 have a sufficient width so that they could be whipped around the tubular metal core 25 at least twice completely. As has also already been mentioned, the main axis is essentially determined by the length of the shaft, the main axis preferably being somewhat longer than the shaft.

The different layers of the casing are arranged alternately, starting, for example, with a lower layer of resin-impregnated graphite fibers, followed by a layer of glass fibers, whereupon another layer of resin-impregnated graphite fibers is applied, to which a further layer of glass fibers follows. In FIG. 1, for example, the glass fiber layers 24 and 27 alternate with the graphite fiber layers 26 and 28 .

With each subsequent layer of resin-impregnated, directional reinforcing fibers, however, it should be noted that the reinforcing fibers 20, 22 are oriented at an orientation angle between approximately 5 ° and approximately 20 ° to the longitudinal axis of this layer, this orientation angle preferably being approximately 10 °. The orientation angles for the graphite fibers are preferably the same for each subsequent layer 26, 28 of the resin-impregnated graphite fibers, but with the opposite sign for each subsequent layer. Thus, the gain 1 or graphite fibers 20 in the layer 28 at an angle R ₁ and the reinforcing fibers or graphite fibers are of the layer 26 is disposed at an angle 22 to the longitudinal axis R ₂ in Fig..

In the embodiment of FIGS. 1, 2 and 5, the envelope contains a rectangular layer 19 . This layer 19 is a metal adhesive. The width of the rectangular layer 19 is sufficient to easily enclose the metal core 25 . The metal adhesive layer 19 must bind the resin-impregnated graphite fiber layer 28 to the tubular core 25 . The metal adhesive is one that is normally used for the bonding of plastics to metals, e.g. B. an elastomeric, modified epoxy resin or an elastomeric, modified phenolic urea resin. An example of such an adhesive is a polysulfide elastomeric, modified epichlorohydrin-bisphenol resin. Many of these adhesives are commercially available, one known as Metallbond 1133, which is an elastomeric, modified epoxy material available from the Narmco Division of Celanese Corporation, New York, V. ST. A. is sold. Another adhesive is FM123-2, sold by American Cyanamid, Wayne, V. St.A. The metal adhesive can be applied to the top of the glass fiber layer 24 if the physical consistency of the adhesive allows it. It can also be brushed or sprayed onto the circumference of the metal core 25 . According to a preferred embodiment, the adhesive is applied in the form of a thin film ( FIGS. 1, 2 and 5).

It has been shown that it is particularly geous before to brush or spray a solution of the same adhesive as it is in the layer 19 to the outside of the metal core 25 after the metal core 25 has been cleaned.

In general, the weight of the metal adhesive layer 19 ranges from about 0.0089 to about 0.0196 g / cm ² , with a weight of the adhesive layer 19 of about 0.0146 g / cm ^{2 being} preferred. With the amount of adhesive to be used, it should be taken into account that not only does a corresponding bond occur between the synthetic resin and the metal core 25 , but also that sufficient torsional rigidity of the metal core 25 is achieved with the longitudinal rigidity of the graphite fiber reinforcement.

In any case, a polygonal laminate, consisting of the adhesive layer 19 , resin-impregnated graphite fibers 20, 22 and a glass fabric (layers 24 and 27 ) is placed around the circumference of the metal core 25 . The adhesive is of course brought into contact with the tubular metal core 25 , and the endless, directed graphite fibers 20, 22 are aligned at an angle between ± 5 ° to ± 20 ° to the longitudinal axis of the metal core 25 , while the woven glass fiber layers 24, 27th are aligned so that the glass fibers 21 lie at an angle of 0 ° or 90 ° to the longitudinal axis of the metal core 25 . After the metal core 25 has been coated with the required layers, this structure can be held together using a cellophane tape. The structure can also be held together by a heat shrinking polypropylene film (not shown) which acts as a shape and is removed in the manner to be described below.

After covering the metal core 25 with the required number of layers, the arrangement is heated in an oven in order to achieve a bond between the individual layers to one another and to one another. The temperature to which the assembly is heated depends on several factors, including the type of resin used to impregnate the graphite fibers 20, 22 . These temperatures are well known. For a modified epoxy resin with which the graphite fibers 20, 22 are impregnated, the temperature is in the range from approximately 100 ° C. to approximately 180 ° C. and preferably approximately 140 ° C.

If a polypropylene film is applied on the outside in order to hold the various layers around the core 25 , this can very easily be peeled off manually from the surface of the shaft. Irregularities in the surface can be removed by sanding or grinding and similar processes. If required, the shaft can be coated with a color.

In view of the fact that it is not always possible to achieve a completely flat end face of the shaft, layer blanks which are somewhat longer than the final length of the shaft to be produced are generally used. A rounded shoulder 6 , as shown in Fig. 6, can be avoided by making a radial cut through the shaft behind the shoulder 6 , whereby a completely straight edge is achieved if this is desired for the shaft.

example

The production of a drive shaft for a truck is described. For such an application, the metal core 25 normally has a length of 1.22 m to 3.05 m, an inner diameter in the range of 5.08 to 11.43 cm and an outer diameter in the range of 5.08 to 12.7 cm. The core 25 carries a layer 19 of a metal adhesive with a weight in the range of approximately 0.0098 to 0.0196 g / cm ² . On the metal adhesive layer 19 two layers of a glass fiber fabric and a layer of epoxy resin-impregnated, directed graphite continuous fibers are applied. The glass fibers are at an angle of 0 ° and 90 ° to the longitudinal axis of the shaft, and the graphite fibers are at an angle of about 10 ° to it. The graphite fibers of the subsequent layers are also at an angle of 10 °, but in the opposite direction to the previous layer. The graphite fibers are thus aligned at an angle of ± 10 ° to the longitudinal axis.

As can be seen from FIG. 6, such a drive shaft has a first end part 42 and a second end part 43 and two intermediate regions 44 and 45 . Finally, there is a middle part 46 . The fiber reinforced sheath in the area of the first and second end parts 42 and 43 consist of two wraps of the core 25 . However, the number of wraps changes over the length of the shaft in such a way that the sheath is thickest in the Mittelbe rich of the shaft. For the truck drive shaft, the height of the triangular cut is selected so that six or seven windings of the central part 46 of the shaft are present, the number of windings in the intermediate regions 44 and 45 decreasing over the length of the shaft.

In contrast, a passenger car drive shaft would have an aluminum core 25 with a length between 102 cm to 183 cm, an outer diameter between 6.35 cm and 7.62 cm and an inner diameter between 5.72 cm and 6.99 cm. You would wear about two layers of fiberglass and endless graphite fibers impregnated with an epoxy resin. As with the drive shaft of the truck, the graphite fibers are oriented at an angle of ± 10 ° to the longitudinal axis of the shaft, while the Glass fibers lie at an angle of 0 ° and 90 ° to the longitudinal axis of the shaft. In addition, a layer 19 of a metal adhesive is provided between the metal core 25 and the casing.

Claims (6)

1. shaft for the transmission of torques and bending forces, with a tubular metal core ( 25 ) and with a covering made of fiber-reinforced plastic, characterized in that

• a) a metal adhesive layer ( 19 ) is applied to the outer surface of the metal core ( 25 ),
• b) the covering has a plurality of superimposed layers of resin-impregnated, rectified reinforcing fibers ( 20 ) which are placed around the circumference of the tubular metal core ( 25 ), layers between successive reinforcing fibers and between the metal core ( 25 ) with the adhesive layer ( 19 ) and the radially inner reinforcing fiber layer each have a layer of woven glass fibers ( 21 ),
• c) the fibers of each reinforcing fiber layer are oriented at an angle between 5 and 20 ° to the longitudinal axis of the metal core against the orientation of the closest reinforcing fiber layer, and that
• d) each of the layers of reinforcing or glass fibers has such a shape that when the metal core is wrapped with the prefabricated layers, the shaft has a larger diameter in its central region than in the end regions.

2. Wave according to claim 1, characterized in that the Resin is a thermosetting resin. 3. Shaft according to claims 1 or 2, characterized in that the reinforcing fibers ( 20, 22 ) consist of carbon or graphite, the fibers being oriented at an angle of approximately 10 ° with respect to the longitudinal axis of the tubular metal core ( 25 ) are. 4. Shaft according to one of the preceding claims, characterized in that the woven glass fibers ( 21 ) are aligned such that they form an angle of 0 ° or 90 ° with the longitudinal axis of the rohrför shaped metal core ( 25 ). 5. Shaft according to one of the preceding claims, characterized in that the tubular metal core ( 25 ) consists of an aluminum alloy. 6. Shaft according to one of the preceding claims, characterized in that the adhesive layer ( 19 ) has a thickness of about 0.0098 g / cm² to about 0.0196 g / cm ² .