WO1994000290A1

WO1994000290A1 - Process for producing fibre-reinforced synthetic resin mouldings

Info

Publication number: WO1994000290A1
Application number: PCT/EP1993/001546
Authority: WO
Inventors: Dieter Pippart; Gerhard Greb
Original assignee: Glacier Gmbh - Deva Werke
Priority date: 1992-06-22
Filing date: 1993-06-17
Publication date: 1994-01-06
Also published as: HU212230B; HU9400488D0; DE4220327C1; EP0603364A1; PL302402A1; CA2114801A1; AU4419093A; ZA934198B; CZ37694A3; HUT71531A; FI940622A0; JPH06510250A; BR9305570A; FI940622A

Abstract

In a process for producing fibre-reinforced synthetic resin mouldings (17), in which the fibres soaked in synthetic resin are wound upon a spindle (5) and the wound bodies (22) thus produced are cured by heating and subsequently worked, a mould shell (2) or several mould shells (2) separated by a partition plate (3) as separating supports (3') are drawn on a rotary shaft (1) and axially clamped together integrally in rotation thereupon to form a spindle (5). The fibres soaked in synthetic resin are then wound on the spindle (5) between the supports (3') up to a radial thickness of the wound body (22) which is greater than the radial extent of the supports (3') or the partition plates (3). As soon as it has cured, the wound body (22) is radially worked off between the supports (3') to the radial extent of the partitions (3) or the supports (3') if there are no partitions (3), the clamping force is released and then the individual, separated mouldings (17) are drawn off the spindle (1).

Description

Process for the production of fiber-reinforced synthetic resin molded articles

The invention relates to a method for producing fiber-reinforced synthetic resin molded bodies, in which synthetic resin-impregnated fibers are wound onto a winding mandrel and the winding body thus produced is cured by heating and then processed.

The use of modern winding technology in the manufacture of fiber-reinforced synthetic resin moldings opens up new design options in many technical areas due to rational manufacturing options and the high strength of wound bodies. In particular in connection with the use of high-strength materials, it leads to the revision of many conventional constructions, in which fiber-reinforced synthetic resin is already used, but also to considerations in constructions that previously used other materials, e.g. Steel, were reserved to use fiber-reinforced synthetic resin parts manufactured in the winding process. This increased demand requires ever more rational production methods for the production of such synthetic resin bodies, not only with regard to mass production, but also for small series and for one-off production, in which the proportion of non-production times is particularly high. This is particularly the case with small series and individual parts in addition to simplifying production processes and reducing the number of manufacturing steps. B. especially minimizing set-up times and avoiding any reworking of individual parts.

One way to reduce the manufacturing idle times is to have several similar elements from a semi-finished product, such as a fiber-reinforced synthetic resin blank produced in the winding process. From DE-GM 76 19 591 a profile grinding machine is known which grinds several round or oval parts from the outside in one working or grinding process by means of a profile grinding roller and a feed roller from a c cylindrical blank. This known profile grinding roller has several identical profile grinding sections lying next to one another, the radial outer contour of which corresponds in each case complementarily to the radial outer contour of the part to be produced. The radial distance between the high and the

I Q low point of a Profilschlei section corresponds at least to the radius of the cylindrical blank, so that with the completion of the shaping of the parts to be manufactured they are also separated from each other at the same time. In this known profile grinding machine, there must be a separate profile grinding roller for each type of molded part to be produced. Short-term variations

, c in the composition of the synthetic resin moldings to be produced, e.g. the

Manufacture of shaped bodies of different lengths with the same radial extent is not possible with such a profile grinding roller, which profile is not easily changed.

20 For the manufacture of self-lubricating composite bearings, a process for the production of fiber-reinforced, wound synthetic resin moldings is known from US Pat. No. 4,867,889, in which synthetic resin-impregnated fibers are wound onto a winding mandrel. The winding process takes place in two steps with a first, thinner layer of PTFE fibers, which are twisted with 5 fibers of a polymer matrix and are soaked in a synthetic resin bath enriched with carbon particles before the winding process, and a second thicker layer of z. B. glass fibers that are wound up to the required thickness of the winding body produced. The finished package is cured by heating and then removed from the Q mandrel. The winding bodies produced in this way are given the final radial and axial outer contour in separate work steps, since these processing tools for each composite material bearing have to be controlled via measuring devices in order to maintain the desired dimensions of the composite material bearing. Since this processing step has to be carried out individually for each composite OK material store, considerable set-up and processing times are incurred. Here, the invention is intended to remedy this situation and to improve a method of the type mentioned at the outset such that a simpler yet faster manufacture of such shaped bodies can be carried out, and conversion to molded bodies of a different shape is possible without great effort and is required for the shaped bodies produced Post-processing requires only a small amount of equipment and is also greatly reduced.

According to the invention, this is achieved in a method of the type mentioned at the outset in that one shaped sleeve or a plurality of shaped sleeves, each separated from one another by a cutting disk, and as an axial closure on both sides

Support elements are mounted on a rotary shaft and braced axially in a rotationally fixed manner to form a winding mandrel, then the synthetic resin-impregnated fibers up to a radial thickness of the winding body that is greater than the radial extension of the support elements or the separating disks, at least between the Support elements are wound onto the winding mandrel, then the hardened winding body between the support elements is worked down to the radial extent of the cutting discs or the supporting elements, if there is no cutting disc, and then the bracing is released, after which the individual or each other separate molded body is withdrawn from the rotary shaft.

The method according to the invention allows one or more fiber-reinforced synthetic resin molded articles to be produced simultaneously in a few simple operations. The fact that the fibers are not wound directly on a rotary shaft used as a Wickeidorn, but the winding mandrel is in turn composed of cutting disks, shaped sleeves and support elements arranged on its axial ends, which are mounted on a rotary shaft and then axially fixed against one another, is possible , each of the moldings to be produced has its own

To assign molded sleeve, the radial outer contour of which already defines the radial inner contour of the molded body. On the other hand, the shaped sleeves can be separated from one another by cutting disks and thus even shaped bodies of different shapes can be wound in one operation. Furthermore, it is not necessary to control the winding process in such a way that only fibers are wound onto each of the shaped sleeves, rather the cutting disks and support elements can be easily wrapped, so that an externally uniform-looking winding body is present after the winding process has ended. After the synthetic resin has hardened, the winding body can be mechanically processed, for example ground. Since the radial outer contour of the cutting discs or the supporting elements corresponds to the final shape of the shaped bodies, the radial processing of the winding body achieves two things, at least between the supporting elements except for the expansion of the cutting discs or the supporting elements, if there is no cutting disc: firstly the shaped bodies obtain their finished outer shape without any further mechanical reworking being necessary, and on the other hand they are separated from one another at the same time, since through the processing of the winding body except for the outer radius of the cutting disks, each connection of the shaped bodies to one another the thrust washers are removed so that they can then only be separated from one another by the cutting disks and can be separated immediately by releasing the tension of the winding mandrel (and the resulting separation of cutting disks, shaped sleeves and support elements).

In a preferred embodiment, the radial extent of the support elements and the cutting disks is the same. In the final mechanical radial processing of the winding body, it is not necessary to make certain starting points in this way when attaching the processing means. Mechanical processing can begin at any point on the peripheral surface of the bobbin over the support members at one end and end anywhere on the peripheral surface of the support members at the other end.

In some applications, however, it can also be advantageous to choose a radial extension of the support elements larger than that of the cutting disks when using several shaped sleeves. The synthetic resin-impregnated fibers are only wound between the support elements, as a result of which the winding body produced is limited in the axial direction from the outset, thus reducing the consumption of fibers. The synthetic resin-impregnated fibers are preferred in a regular

Wound composite wound under controlled pre-tension in a cross composite.

In this way, the bond between the fibers and thus the homogeneity and the load-bearing capacity of the finished package can be increased.

In an advantageous development of the invention, a first layer of synthetic resin-impregnated PTFE and / or high-strength fibers is wound as a bearing sliding layer for the production of bearing shells. The resin impregnation of the fibers to be wound up is carried out in a simple operation in that the fibers are run through a synthetic resin bath enriched with solid lubricants before being wound onto the winding mandrel. A further layer of synthetic resin-impregnated glass fibers is wound as a base layer on such a first layer in the form of a sliding layer. For certain

Areas of application can also be used advantageously other reinforcing fibers, such as carbon or boron fibers. Reinforced, stretched PTFE fibers are preferably used to form the bearing sliding layer, as a result of which the wear resistance of this layer can be increased.

In a very particularly preferred embodiment of the invention, the shaped sleeves have a spherical outer surface and, again advantageously, remain in each case as a structural element in the shaped body when it is pulled off the winding roll. In this case, the radial outer surfaces of the molded sleeves, onto which the fibers impregnated with synthetic resin are wound, are preferably designed as sliding surfaces. In this way, for example in the production of spherical bearings, which have an inner ring with a spherical outer diameter and an outer ring with a spherical bore, the separate production of an outer ring and the complex machining of its spherical inner diameter are avoided. A separate production of the sliding layer and its subsequent introduction into the spherical inner diameter of the outer ring is also eliminated. In addition, the production of a split outer ring or the blasting of the outer ring and the subsequent insertion of the inner ring is avoided, which greatly simplifies and shortens the production of, for example, a radial spherical plain bearing. In a preferred development of the invention, a sliding film or a suitable sliding fabric, for example PTFE fiber fabric, is applied to the sliding surface of the molded sleeves, whereupon the resin-impregnated fibers are then wound up. As a result, there is hardly any need to dispense with the application of a first fiber layer as a sliding layer. In this embodiment, the base layer made of fibers impregnated with synthetic resin is immediately wound onto the slide film, the slide film remaining in the finished molded body.

In a further advantageous embodiment of the invention, the axial outer surfaces of the cutting disks or that of the support elements or their heads define the finished axial end surfaces of the shaped bodies. With a corresponding shaping of the axial outer surfaces of the cutting disks or the supporting elements, any complementary axial outer surfaces of the

Moldings which e.g. can also have undercuts. It is no longer necessary to process these surfaces in a further operation. After the radial processing of the winding body, there are thus completely finished shaped bodies, the radial inner surface of which is provided by the radial outer surfaces of the shaped sleeves, the axial end faces of which are by the corresponding side surfaces of the cutting disks or the support elements, and the radial outer circumference of which is the radial extent of the opening disks or the support elements are defined.

The invention is explained in more detail below in principle by way of example with reference to the drawing. Show it:

1 shows a longitudinal section through a basic illustration of support elements, cutting disks and shaped sleeves which are being pulled onto a rotary shaft just to form a winding mandrel for carrying out a method according to the invention;

2 shows a longitudinal section through a winding mandrel wound with fibers, the winding body being shown above the longitudinal axis of the rotary shaft during the radial processing and below the longitudinal axis in its radially processed state, and Fig. 3 in cross-section finished, wound molded body, which are separated from each other and from the cutting discs or the support elements after the radial processing of the winding body and are withdrawn from the rotary shaft.

The manufacture of radial spherical plain bearings is shown as an exemplary embodiment in the figures.

First, shaped sleeves 2 and cutting disks 3 are alternately mounted on a rotary shaft 1 (FIG. 1), the sequence beginning and ending with a support element 3 ¹ . The support elements 3 'can be sleeve-shaped in order to bridge the distance to the elements of the tensioning device 4 (FIG. 2) attached to the ends of the rotary shaft 1. With this clamping device 4, the support elements 3 ¹ , form sleeves 2 and

Cutting disks 3 are axially fixed against each other so that a mandrel 5 is formed, the radial outer surface 6, on which the fibers are to be wound, is not smooth, but profiled. The shape of this profiling is determined by the shape of the shaped sleeves 2, cutting disks 3 and support elements 3 ¹ and can thus be adapted to the particular requirements in a relaxed manner.

In the example shown, the radial outer surfaces 7 of the shaped sleeves 2 are spherically shaped and provided with flat end surfaces 8 in the axial direction. The cutting discs 3 comprise a rectangular web arranged radially on the inside

9 and a radially outer head 10 projecting at right angles to the shaped sleeves 2 axially beyond the web 9. Here, the axial extension of the cutting discs 3 is configured such that it gives the shaped body the desired axial contour with undercuts. Clamping or sealing elements corresponding to the standard can later be introduced into these undercuts. With the radial inner surface 11 of the webs 9, the cutting discs 3 rest on the rotary shaft 1, while the axial outer surfaces 12 of the webs 9 rest on the flat end surfaces 8 of the shaped sleeves 2. The axial outer surfaces 13 of the head 10 of a cutting disc 3, starting from the protrusion over the web 9, initially in the radial direction perpendicular to the longitudinal axis 14 of the rotary shaft 1 and then obliquely to the neighboring shaped sleeve 2 αbgewαndten side in the radial outer surface 15 of the cutting disc 3, so that an undercut is formed in the axial end surface 1 of the molded body 17 to be wound. The radial outer surface 15 of the cutting disc 3 is flat in the example shown and parallel to the longitudinal axis 14 of the rotary shaft

1.

The axial outer surfaces 13 of the heads 10 of the cutting disc 3 correspond complementarily to the desired shape of the axial end surfaces 16 of the shaped bodies 17. With their heads 10, the cutting discs 3 engage somewhat over the molded sleeves 2, the axially outer and radially inner edges 18 of the head 10 rest on the spherical outer surfaces 7 of the shaped sleeve 2. In the area of the shaped sleeves 2, the design of the outer surfaces (9 ', 10', IT, 12 ') of the support elements 3' corresponds to that of the cutting discs 3.

There is one molding sleeve for each plastic molding 17 to be produced

2 provided. The outer diameters of the cutting disks 3 and the support elements 3 'are identical to one another and larger than the diameter at the apex 19 of the shaped sleeves 2, which are likewise identical to one another. The shaped sleeves 2 shown correspond to the conventional inner rings used for the manufacture of radial spherical plain bearings have usually been used so far. They should remain in the molded body 17 to be produced as a structural element, in other words as an inner ring. The shaped sleeves 2 can also be made entirely solid or as a hollow body.

On the support elements 3 ', which are braced to form a winding mandrel 5, cutting discs

3 and shaped sleeves 2, a first layer 20 of, for example, resin-impregnated, reinforced, stretched PTFE and high-strength fibers is wound in a first winding pass, which are soaked before winding in an epoxy resin bath, which is enriched with solid lubricants in the form of graphite powder . In the hardened state, this first layer 20 forms a bearing sliding layer with good sliding properties. The fibers of this first layer 20 are usually wound cross-wise (at approximately 60 ° to the longitudinal axis of the winding mandrel) and under controlled prestressing directly on or around the spherical sliding surface of the shaped sleeves 2. As an alternative to producing the sliding layer from wound synthetic resin-impregnated fibers, this sliding layer could also be applied in the form of a suitably prepared, suitable sliding film or sliding fabric.

A second layer 21 of glass fibers soaked in epoxy resin is then wound onto this first fiber layer 20 and form a base layer in the hardened state. Here, the glass fibers are wound under controlled pretension in a cross connection (at approx. 45 ° to the longitudinal axis of the mandrel) until a predetermined outer diameter is reached, which is greater than the radial expansion of the cutting discs 3 and support elements 3 '.

After reaching a predetermined winding thickness of the winding body 22, the winding process is ended and the resulting winding body 22 is cured by heating. It is then radially ground down to the outer circumference of the support elements 3 ¹ and cutting disks 3 over the entire length of the winding body 22 with a grinding wheel 24 (FIG. 2), as a result of which the shaped bodies 17 receive their desired radial dimension and at the same time are mutually separated .

Now the axial bracing of the winding mandrel 5 is also released, after which the shaped bodies 17 can be separated from the supporting elements 3 ¹ and cutting disks 3 and the radial spherical plain bearings are present as finished individual parts 23.

Additional reworking of the radial spherical plain bearings produced in this way is no longer necessary, since the shaped sleeves 2 remain as structural elements, namely as inner rings, in the outer rings made of hardened, fiber-reinforced synthetic resin surrounding them, the first winding layer 20, which is designed as a sliding layer, compared to the each facing sleeve 2 is rotatable.

The radial spherical plain bearings produced in this way have the advantage that they are almost completely maintenance-free and have the best corrosion resistance, as well as a favorable weight and favorable sliding properties (low friction) between the inner ring and outer ring, furthermore great resistance to dirt as well as high impact and impact resistance and generally a very high level good resilience αut

An example for the production of spherical and spherical plain bearings with a bearing width of 18 mm and a width of the steel bushing of 22 mm is described below:

For the production, 32 shaped sleeves in the form of ball bushings with a ball radius of 40.7 mm in connection with spacer rings are placed on a winding mandrel with a diameter of 30 mm and clamped axially against each other by means of a clamping nut. The mandrel, ball bushings and spacer rings had been carefully cleaned beforehand. The surfaces of the ball bushings and the spacer rings are then covered with a suitable release agent. treated. The outer diameter (47 mm) of the spacer rings corresponds to the desired outer diameter of the ones to be manufactured, which are seated on the ball bushings

Shaped bodies in the form of spherical rings. The width of the ball rings and thus the bearing width (18 mm) is determined by flat radial surfaces on the side of the spacer rings.

During the winding process, the ball bushing (consisting of a sliding layer and a base layer) is wound. The sliding layer consists of PTFE composite threads, namely of PTFE fibers that are twisted with polyamide fibers (such as DACRON from Dupont) and have a final texturing of 660 den. These PTFE composite threads are coated with an epoxy resin based on toluene (SINOTHERM 4301 from the company

Hüttenes-Albertus), which is provided with an addition of 12.5% by weight of natural graphite (as is commercially available under the trade name Atoin 3033). The PTFE composite threads so impregnated with epoxy resin are then wound onto the ball bushings at a constant thread speed of 48.73 m / min. Then it dries in one

Continuous furnace for 20 min. at 1 10 ° C.

The base layer is then wound up. For this, glass fiber threads become one

Texturing of 1,200 den, also with an epoxy resin based on toluene (SINOTHERM 4301 from Hüttenes-Albertus, but without

Addition of natural graphite) were soaked in a cross bond at 60 ° Winding angle at a uniform winding speed of 48.73 m / min. wound up. After the desired outer diameter (47 mm) has been reached, another closed winding layer is then overwound in order to create a bond between the individual parts between the spacer rings, with an excess of about 1-2 mm being wound. This is followed by a short drying in a continuous oven, after which there is a. Curing in a curing oven for 90 min. at 90 ° C.

In a subsequent machining process, the hardened composite pipe is ground down to a finished ball bushing dimension (47 mm) on a grinding mandrel. After loosening the clamping nut, the individual spherical bearings and spacer rings can then be removed from the grinding arbor.

Claims

Expectations

1. A process for the production of fiber-reinforced synthetic resin molded bodies, in which synthetic resin-impregnated fibers are wound onto a winding mandrel and the winding body thus produced is cured by heating and then processed, characterized in that one molded sleeve (2) or several each by a cutting disc (3 ) separate molded sleeves (2) and supporting elements (3 ¹ ) are drawn onto a rotary shaft (1) as axial ends on both sides and braced axially in a rotationally fixed manner to form a winding mandrel (5), then the synthetic resin-soaked fibers up to a radial thickness of Winding body (22), which is larger than the radial extension of the support elements (3 ¹ ) or the cutting discs (3), are wound between the support elements (3 ') on the winding mandrel (5), then the winding body ( 22) after its hardening radially between the support elements (3 ¹⁾ to the extension of the blades (3) or of the distances tzelemente (3 ^1), if no cutting disc (3) is present, processed and the tension is released and then the or each separated from one another form-body (17) is withdrawn from the rotary shaft (1) is / are.

2. The method according to claim 1, characterized in that the radial Er¬ extension of the support elements (3 ¹ ) and cutting discs (3) is the same size.

3. The method according to claim 1, characterized in that when using several shaped sleeves (2), the radial extent of the support elements (3 ') is greater than that of the cutting discs (3).

4. The method according to any one of claims 1 to 3, in which the synthetic resin-impregnated fibers are wound up in a regular winding assembly, characterized in that the synthetic resin-impregnated fibers are controlled Preload can be wound in a cross bond.

5. The method according to any one of claims 1 to 4, in which to produce bearings on the mandrel first a first layer of fibers, which are soaked in a synthetic resin bath enriched with solid lubricants, to form a sliding layer and then a second fiber layer to form a Base layer are wound, characterized in that twisted stretched PTFE fibers are used to form the sliding layer with high-strength reinforcing fibers.

6. The method according to any one of claims 1 to 5, characterized in that shaped sleeves (2) with a spherical outer surface (7) are used.

7. The method according to any one of claims 1 to 6, characterized in that when removing the shaped body (17) from the rotary shaft (1), the shaped sleeves (2) are each left as a structural element in the shaped bodies (17).

8. The method according to any one of claims 1 to 7, characterized in that the radial radial surfaces (7) of the shaped sleeves (2) are designed as sliding surfaces.

9. The method according to any one of claims 1 to 8, characterized in that a sliding film (20) is applied to the radial circumferential surface of the shaped sleeves (2) before winding up the resin-impregnated fibers.

10. The method according to any one of claims 1 to 9, characterized in that the axial side surfaces (13) of the cutting discs (3) and support elements (3 ') define the axial end surfaces (16) and contours of the shaped body (17).