Rolling bearing cage and spindle bearing with such a rolling bearing cage

Abstract

Rolling bearing cage (4, 4d - 4f) with two side rings (9, 10) arranged parallel to one another and a plurality of webs (11) connecting these two side rings (9, 10), in which the side rings (9, 10) and two immediately adjacent webs (11) each form a cage pocket (6) for receiving a rolling element (5), in which the side rings (9, 10) with the webs (11) form a one-piece body, and in which the body consists of a fiber-reinforced plastic matrix, wherein the body has several layers (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33), wherein these layers (15 - 33) have a common matrix material in which different fiber arrangements are embedded, wherein the fiber arrangements differ from one another in their material and / or structure and wherein one layer (16, 20, 22) has a fiber reinforcement which has an increased stiffness compared to other layers,characterized in that the individual layers (23 - 33) of the body are arranged axially next to one another.,

Description

Field of the invention

[0001] The invention relates to a rolling bearing cage with two parallel side rings and a plurality of webs connecting these two side rings. The side rings and two immediately adjacent webs each form a cage pocket for accommodating a rolling element. The side rings and the webs form a one-piece body, and the body is made of a fiber-reinforced plastic matrix. Furthermore, the invention relates to a spindle bearing with such a rolling bearing cage. Background of the invention

[0002] Rolling bearing cages are known that consist of a cured synthetic resin with embedded fibers. The cured synthetic resin is usually referred to as the matrix of such a fiber composite material. An epoxy resin or a phenolic resin can be used as the synthetic resin, for example. The fibers are typically made of glass, carbon, aramid, or cotton. They are arranged, for example, as woven fabrics and / or as unidirectional fibers in the fiber composite material. Such cages made of fiber composite materials can be used in spindle bearings, where they are usually guided on the outside of a bearing outer ring or arranged in a rolling element-guided manner.

[0003] DE 10 2006 007 925 A1, for example, shows a rolling bearing designed as a single-row angular contact ball bearing for supporting a machine tool main spindle, wherein a bearing cage of this rolling bearing is designed as a hard fabric cage or plastic cage, which consists of two side rings and several transverse webs connecting these side rings to one another, and which is guided on an outer bearing ring of the rolling bearing.

[0004] Such a spindle bearing cage must generally be suitable for very high bearing speeds. At the same time, it should be as wear-resistant as possible during operation. Therefore, the properties of the cage's reinforcing fabric are particularly important. However, a homogeneous fiber reinforcement can only ever meet a compromise between requirements such as stiffness, emergency running properties, moisture swelling, and thermal expansion. When selecting the fiber material for reinforcing the resin matrix, prioritizing one specific property leads to a deterioration of one or more other properties of the cage.

[0005] For hard fabric cages of spindle bearings, in addition to the conventional, virtually single-material reinforcing fabrics, mixed fabrics have already been developed. These are consistently contained in the plastic matrix of a rolling bearing cage, but exhibit anisotropic properties. This should allow these cages to better withstand high centrifugal forces and high thermal loads. At the same time, the cage design is as delicate as possible.

[0006] DE 10 2013 225 339 A1 discloses an outboard-guided rolling bearing cage in which the cage body consists of two side rings that are integrally connected to one another by a number of webs to form cage pockets. The body is constructed from a plastic matrix into which a blended fabric is embedded for reinforcement and is continuously present throughout the entire body. The blended fabric is composed of two or more fiber types, synthetic fibers and / or natural fibers, that differ in their properties. For example, in the warp direction, i.e., the circumferential direction, the blended fabric contains a portion each of aramid fibers and cotton fibers, while in the weft direction, i.e., the axial direction, only cotton fibers run. This blended fabric exhibits direction-dependent properties.A cage constructed in this way has a higher tensile strength and a higher modulus of elasticity, particularly in the circumferential direction, and thus greater rigidity than in the axial direction. The cage's coefficient of thermal expansion is lower in the circumferential direction than in the axial direction. A slight expansion of the cage under high thermal and mechanical loads allows for relatively small clearance between the cage and the bearing outer ring in the outboard guide.

[0007] EP 2 871 378 A2 discloses a cage for rolling bearings that addresses the problem of weld line strength caused by the injection molding manufacturing process. Sharp edges, tight radii, or an unfavorable orientation of short reinforcing fibers can lead to stress peaks when loads are transferred from the rolling elements to the cage, ultimately leading to cage fracture. To prevent this, the cage has a bracing system with at least one pre-impregnated fiber. The method for manufacturing such a rolling bearing cage is also disclosed.

[0008] EP 3 006 753 A1 discloses a rolling element cage consisting of a base body and a resin portion. The base body has a higher strength than the resin portion. The resin portion is formed around the base body by injection molding and contains solid lubricant particles.

[0009] EP 2 476 925 A1 discloses a rolling element cage made of two different materials. One material is a fiber composite material, the other is a plastic. The plastic contains no fibers or contains different fibers than the fiber composite material. The cage has fiber composite sections made of fiber-reinforced plastic material. At least one plastic section is bonded to a fiber composite section. The cage's purpose is to ensure low-wear operation over wide temperature ranges. Object of the invention

[0010] Against this background, the invention is based on the object of further developing a rolling bearing cage of this type with regard to its wear behavior, suitability for high speeds, and design flexibility. In particular, such a rolling bearing cage should be suitable for use in a high-speed spindle bearing. Description of the invention

[0011] The object is achieved by a rolling bearing arrangement according to claim 1 or claim 2. The invention is based on the finding that in a fiber-reinforced rolling bearing cage, by means of a multi-layer, layer-specific structure, the favorable properties of various fiber materials, such as lubricant storage capacity, sliding friction coefficient, tensile strength, rigidity, thermal expansion coefficient and so on, can be used at those points or in those areas of the cage where the respective properties are particularly required and / or have a particularly advantageous effect.

[0012] The invention is therefore based on a rolling bearing cage with two side rings arranged parallel to one another and a plurality of webs connecting these two side rings, in which the side rings and two immediately adjacent webs each form a cage pocket for receiving a rolling element, in which the side rings form a one-piece body with the webs, and in which the body consists of a fiber-reinforced plastic matrix.

[0013] To achieve this objective, the invention provides that the body comprises several layers, that these layers share a common matrix material in which various fiber arrangements are embedded, and that the fiber arrangements differ from one another in their material and / or structure. One layer comprises fiber reinforcement, which has increased rigidity compared to other layers.

[0014] In a further development of this feature, it can be provided that a layer arranged on or near the inner diameter of the body has a fiber reinforcement which has an increased stiffness compared to other layers.

[0015] A layer is defined as a structure consisting of one fabric layer or several adjacent, identical fabric layers or as a structure consisting of one continuous fiber layer or several adjacent, identical continuous fiber layers.

[0016] A woven fabric is defined as a fiber arrangement in which the fibers are arranged at an angle to each other. A continuous fiber is defined as a unidirectionally wound fiber arrangement.

[0017] By utilizing a multi-layered body structure that combines the advantages of several materials through a locally differentiated combination of different materials, the properties of a rolling bearing cage for a high-speed rolling bearing, such as a spindle bearing, can be better adapted to the operational requirements and loads of such a bearing. According to the invention, the cohesion of the individual layers with different fiber arrangements is achieved by a common matrix material made of a resin or a resin-like material. The individual layers contain different fiber arrangements to optimize the properties of the cage.

[0018] In particular, the friction of the cage at contact points with the bearing rings can be reduced, thus improving the sliding friction and wear behavior of the cage, which increases the service life of the cage and reduces the maintenance effort for a spindle supported by such a bearing. Furthermore, improved thermal expansion behavior and moisture swelling behavior of such a cage can be achieved. This can reduce the guide clearance of the cage on the bearing rings and / or the play of the rolling elements in the cage pockets. Nevertheless, the emergency running properties of the bearing are fully maintained or even improved even with a small guide clearance in the event of insufficient lubrication of the cage, which can occur in rolling bearings with very high speeds.The geometric structure of the body with different fiber layers and / or fiber areas can be variably adapted to the requirements of a particular application and designed accordingly.

[0019] It should be noted here that the matrix of the fiber composite material can also be formed from a thermoplastic material instead of a resin, i.e., a thermoset, without deviating from the core of the invention described. Of course, it must be ensured that the plasticizing temperature of such a thermoplastic material is significantly higher than the expected operating temperature of such a bearing.

[0020] According to one solution, the body consists of a multi-layer structure, with the individual layers arranged axially next to one another. Accordingly, two or more layers with different reinforcement properties can be wound axially next to one another and arranged within the body.

[0021] According to a first, second solution, the body consists of a multi-layer structure, wherein the multi-layer structure comprises layers arranged radially one above the other and axially adjacent to one another. Accordingly, radially arranged and axially arranged layers with different reinforcement properties can be combined in the body.

[0022] The invention enables a configuration of the rolling bearing cage with fiber-reinforced layers, each of which specifically improves certain properties of the cage, such as particular suitability for high speeds, particularly good friction and wear behavior, and design freedom, and thus, in the combination of these properties, has a beneficial effect on the entire cage.

[0023] Suitability for high speeds is an important design criterion, especially for spindle bearings. The bearing cages of such spindle bearings are usually guided by an external flange. The required radial guide clearance between the outer side of the cage and a flange on the bearing outer ring should be as small as possible to minimize the centrifugal forces and frictional forces caused by the eccentricity of the cage. On the other hand, sufficient radial guide clearance must be present to ensure sufficient residual clearance in the event of cage expansion due to centrifugal forces, thermal expansion upon reaching operating temperature, and possibly swelling due to the influence of moisture, thus ensuring operational reliability at all times.

[0024] In a rolling bearing cage with the features of the invention, the suitability for high speeds can be improved by arranging a fiber reinforcement with a high modulus of elasticity, i.e., high rigidity, at a suitable location, for example, in a layer on or near the inner diameter of the cage. This can limit or significantly reduce changes in the cage diameter due to operating and / or environmental influences. Furthermore, the increased rigidity of certain fiber-reinforced layers can simplify the design of a cage suitable for high speeds.

[0025] According to a further embodiment of the invention, a layer of the body of the rolling bearing cage, the surface of which is in contact with a guide surface on a bearing outer ring or on a bearing inner ring, can be provided with a fiber reinforcement that has a lower coefficient of sliding friction than other layers. A low coefficient of sliding friction of such a layer can be achieved, for example, by having small depressions or grooves on its surface in which a lubricant can be deposited.

[0026] Since the contact surface of an outboard-guided rolling bearing cage forms a plain bearing with an adjacent guide surface on the bearing outer ring, the tribological properties of this contact surface are particularly important. In a rolling bearing cage according to the invention, the friction and wear behavior can be improved by arranging and acting on a fiber-reinforced layer with a comparatively low coefficient of sliding friction at the relevant contact points, for example, on the outer diameter of the rolling bearing cage.

[0027] At this point, it should be noted that the designs for bearing cages with an outboard guide are to be understood as examples. For bearing cages with an inboard guide or with a rolling element guide, corresponding concepts are possible with regard to the design of the body with the aforementioned layers of special sliding properties or rigidity, and can be easily implemented by a person skilled in the art with knowledge of the present invention.

[0028] According to a further embodiment of the invention, one layer of the body of the rolling bearing cage can be provided with fiber reinforcement with increased tensile strength compared to other layers. Accordingly, the design of the rolling bearing cage and, if applicable, other bearing components, such as sealing elements, can be simplified and designed more freely with the aid of at least one layer with increased tensile strength. In particular, this enables rolling bearing cages with relatively delicate webs between the cage pockets. If necessary, this can increase the number of rolling elements on a given pitch circle, thus increasing the load-bearing capacity of the bearing without requiring additional installation space.

[0029] According to another embodiment of the invention, it can be provided that a first fiber reinforcement is designed as a reinforcing fabric which is constructed from identical fibers in the circumferential direction and in the axial direction.

[0030] According to a further embodiment of the invention, it can be provided that a second fiber reinforcement is designed as a mixed reinforcement fabric which is constructed in the circumferential direction and / or in the axial direction from one or more types of fiber mixtures.

[0031] According to another embodiment of the invention, it can be provided that a third fiber reinforcement is constructed from unidirectionally wound continuous fibers of one fiber type.

[0032] According to a further embodiment of the invention, it can be provided that a fourth fiber reinforcement is constructed from unidirectionally wound continuous fibers of several fiber types.

[0033] Accordingly, one or more layers can consist of a woven fabric, i.e., a crosswise fiber arrangement, while one or more other layers consist of continuous fibers, i.e., a unidirectionally wound fiber arrangement only in the circumferential direction. It is also possible to provide only woven layers or only continuous fiber layers for all layers in a rolling bearing cage with the features of the invention.

[0034] In the simplest case, a fabric can be made up of identical fibers in the warp and weft directions. Another fabric can be made up of one type of fiber in the warp direction and a different type of fiber in the weft direction. More complex fabrics can consist of a fiber blend with two or more different fiber types within one direction. A different fiber blend can be used in the warp direction than in the weft direction. In another variant, single-type fibers can be used in one direction and a fiber blend in the other. Arrangements of continuous fibers wound in the warp direction can be made up of a single fiber type or of fiber blends.

[0035] According to a further embodiment of the invention, the fiber arrangements can consist of individual fibers, threads, and / or yarns. Instead of individual fibers, fibers bonded or twisted together to form threads or yarns can also be used to produce a woven fabric or a continuous fiber structure. These threads or yarns can, in turn, be single-variety or consist of fiber blends.

[0036] The structural design of the fiber arrangements for the individual layers of the cage can be adapted very variably to the requirements of the respective application thanks to this variety of possible variants of fiber arrangements.

[0037] According to a further embodiment of the invention, it can be provided that the fiber arrangements comprise at least one type of fibers from the group of cotton fibers, carbon fibers, aramid fibers, ceramic fibers, glass fibers, boron fibers, polyetheretherketone fibers, basalt fibers, polytetrafluoroethylene fibers, polyethylene terephthalate fibers, flax fibers, hemp fibers, jute fibers, sisal fibers, bamboo fibers, ramie fibers.

[0038] The choice of fiber materials for the individual cage layers can therefore be variably adapted to the requirements of the respective application. Polyamide fibers, such as aramid fibers, exhibit high strength. Thermoplastic fibers such as PEEK, PTFE, and PET are characterized by their acid resistance, temperature resistance, and / or low coefficient of sliding friction. Carbon fibers exhibit high strength and low weight. Glass fibers are suitable as reinforcement materials for most plastics and resins. Ceramic fibers can withstand very high temperatures. Natural fibers from renewable raw materials such as cotton, flax, hemp, jute, sisal, bamboo, or ramie exhibit good lubricant storage capacity and are also considered environmentally friendly.

[0039] For example, in an outboard-guided cage, the use of cotton fiber reinforcements is particularly advantageous, particularly in the axial direction, due to their good lubricant storage capacity on the outer cage surface in contact with the bearing outer ring. On the inside and inside of the rolling bearing cage, the use of carbon fibers is advantageous, particularly in the circumferential direction, due to their low thermal expansion and high rigidity. In a multi-layer structure in the axial direction, at least in one of the axial layers, which includes the cage pockets, the contact surfaces between the cage pockets and the rolling elements accommodated therein can be made of a fiber material with particularly favorable tribological properties.

[0040] The person skilled in the art has at his disposal numerous further expedient and advantageous combination possibilities of the embodiments of the invention mentioned here for achieving certain desired properties of rolling bearing cages.

[0041] Finally, the invention also relates to a spindle bearing, for example a fast-rotating angular contact ball bearing, for supporting a spindle, for example for supporting a main spindle in a machine tool, with a rolling bearing cage which is designed according to the features of the invention. Short description of the drawings

[0042] The rolling bearing cage designed according to the invention is explained in more detail below in several preferred embodiments with reference to the accompanying drawings. Fig. 1 a rolling bearing designed as an angular contact ball bearing in a cross section, Fig. 2 a rolling bearing cage of a rolling bearing according to Fig. 1 in a radial plan view, with a schematic reinforcing fabric according to the invention contained therein, Fig. 3 a rolling bearing cage in section BB according to Fig. 2, with a first schematic radial layer structure, Fig. 4 a rolling bearing cage in section BB according to Fig. 2, but with a second radial layer structure, Fig. 5 a rolling bearing cage in section AA according to Fig. 2, with a schematic radial layer structure, Fig. 6 a rolling bearing cage in section CC according to Fig. 2, with a schematic axial layer structure, Fig. 7 a rolling bearing cage in section CC according to Fig. 2, but with a different axial and schematically shown layer structure, and Fig. 8 a rolling bearing cage of a rolling bearing according to Fig. 1, in a radial plan view, with a further embodiment of a schematic reinforcing fabric according to the invention contained therein. Detailed description of the drawings

[0043] For the sake of simplicity, the figures each show sections of a rolling bearing or rolling bearing cages in which the information essential for explaining the invention is shown.

[0044] This shows Fig. 1 shows a rolling bearing 1 designed as a single-row angular contact ball bearing with a rotational axis R, such as is used, for example, as a rapidly rotating spindle bearing in a machine tool. The aforementioned DE 10 2006 007 925 A1, for example, shows an electric motor-driven main spindle of a machine tool that is mounted by two such angular contact ball bearings.

[0045] The rolling bearing 1 has a bearing outer ring 2, a bearing inner ring 3, a rolling bearing cage 4, and a number of rolling elements 5 designed as balls, each of which is accommodated and guided in cage pockets 6 of the rolling bearing cage 4. The rolling elements 5 are held at equal distances from one another in the circumferential direction of the bearing cage 4. The rolling elements 5 roll on an inner ring raceway 7 of the bearing inner ring 3 and on an outer ring raceway 8 of the bearing outer ring 2.

[0046] The rolling bearing cage 4 consists of a first side ring 9 and a second side ring 10, which are integrally connected to one another by a plurality of webs 11. Two immediately adjacent webs 11 and the associated side ring sections between these two webs 11 each form a cage pocket 6, in each of which a rolling element 5 is arranged. The walls of the cage pockets 6 are simply cylindrical in the example shown. Alternatively, the cage pockets 6 can be spherical or adapted to the rolling elements 5 with a different geometry.

[0047] The rolling bearing cage 4 is in the Fig. In the example shown in Figure 1, the roller bearing cage 4 is guided on the bearing outer ring 2, i.e., it is designed as an outboard-guided cage, with a radial guide clearance FS being present between the radial outer circumference of the rolling bearing cage 4 and the radial inner circumference of the bearing outer ring 2 in the region of a guide surface 35. Alternatively, the rolling bearing cage 4 can be inboard-guided or rolling element-guided.

[0048] The body of the rolling bearing cage 4 consists of a fiber-reinforced plastic matrix. Fig. 2 illustrates this in a radial plan view of a section of the cage 4 with a schematic representation of a fiber reinforcement formed as a fabric 12, which is embedded in a plastic matrix, for example made of an epoxy resin or a phenolic resin. The fabric 12 consists of a plurality of first fibers 13, which run in the circumferential direction, here in the warp direction of the fabric, and of a plurality of second fibers 14, which run in the axial direction, here the weft direction of the fabric 12. The fibers 13, 14 are interconnected crosswise to produce the fabric 12. One fabric layer or several identical such fabric layers placed on top of one another form a layer with reinforcing fibers.

[0049] The rolling bearing cage 4 has a two-layer or multi-layer structure, with different fiber arrangements embedded in the common resin matrix. Fig. 2 to 8 show different embodiments of this multi-layer structure.

[0050] Fig. 3 shows a non-inventive two-layered roller bearing cage 4a in the radial direction in section BB according to Fig. 2, with a radially outer layer 15, which is directly adjacent to a radially inner layer 16. In an outboard-guided cage, the surface of the outer layer 15 is in contact with the bearing outer ring 2, taking into account the guide clearance FS. The outer layer 15 is therefore constructed, for example, from a particularly low-friction reinforcing fabric. The radially inner layer 16, on the other hand, is advantageously constructed from a reinforcing fabric with particularly high tensile strength in the circumferential direction. In the example shown, the radially outer, low-friction layer 15 has a smaller thickness than the radially inner, strength-maximized layer 16.

[0051] Fig. Figure 4 shows a non-inventive, radially four-layered rolling bearing cage 4b ​​with four radially superimposed layers, 17, 18, 19, 20. All four of these layers 17, 18, 19, 20 have different fiber arrangements in their material and / or structure. Alternatively, two layers 17, 19; 18, 20 with the same properties can alternate in a structure. The layer thicknesses are shown in Fig. 4 shown embodiment is approximately the same.

[0052] Fig. 5 shows a non-inventive two-layered roller bearing cage 4c in the radial direction in section AA according to Fig. 2. This rolling bearing cage 4c has a radially outer layer 21 and a radially inner layer 22 immediately adjacent thereto. The radially outer layer 21 has a smaller thickness than the radially inner layer 22. The two layers 21, 22 have different material properties than the two layers 15, 16 according to Fig. 3, but the material properties can also be identical.

[0053] Fig. 6 shows a three-layered axially rolling bearing cage 4d according to the invention in section CC according to Fig. 2. This rolling bearing cage 4d has two narrow, axially outer layers 23, 24, between which a wider, axially middle layer 25 is arranged. The two outer layers 23, 24 can, for example, largely form the two side rings 9, 10 of the cage 4d. The middle layer 25 can largely form a web 11 connecting the side rings 9, 10 and the walls of a cage pocket 6. The two axially outer layers 23, 24 can have the same fiber reinforcement. The middle layer 25 has a different fiber reinforcement than the axially outer layers 23, 24. The middle layer 25 can be constructed from a fiber reinforcement with a low coefficient of sliding friction, so that the friction at the contact surfaces between the rolling element 5 and the cage pocket 6 is low.

[0054] Fig. 7 shows a five-layered rolling bearing cage 4e according to the invention in the axial direction in section CC according to Fig. 2. This rolling bearing cage 4e is constructed from five layers 26, 27, 28, 29, 30 of approximately equal width arranged axially next to one another. In this construction, two different fiber arrangements can be arranged alternately in the layers 26, 27, 28, 29, 30. Alternatively, all layers 26, 27, 28, 29, 30 of this rolling bearing cage 4e can have different fiber arrangements and thus different material properties.

[0055] Fig.Finally, Figure 8 shows a radial plan view of a rolling bearing cage 4f according to the invention, which has a three-layer structure in the axial direction. Accordingly, this rolling bearing cage 4f has three layers 31, 32, 33 of approximately equal width and arranged axially next to one another. These layers 31, 32, 33 are formed by a strip-shaped reinforcing fabric 34, wherein in the warp direction or circumferential direction of the rolling bearing cage 4f, the two axially outer layers 31, 32 consist of the same fibers, and the axially middle layer 33 consists of fibers that are different from the outer layers 31, 32. In the weft direction, i.e., in the axial direction of the rolling bearing cage 4f, the reinforcing fabric 34 consists of uniform fibers. However, such a rolling bearing cage can also have more than just three layers of the same or different fibers. List of reference symbols 1 rolling bearing 2 bearing outer ring 3 Bearing inner ring 4 rolling bearing cage 4a Rolling bearing cage (1st embodiment) 4b Rolling bearing cage (2nd embodiment) 4c Rolling bearing cage (3rd embodiment) 4d rolling bearing cage (4th embodiment) 4e Rolling bearing cage (5th embodiment) 4f rolling bearing cage (6th embodiment) 5 rolling elements 6 cage bag 7 inner ring raceway 8 Outer ring raceway 9 First side ring 10 Second side ring 11 jetty 12 Fabric of the rolling bearing cage 4 13 First fiber in warp direction 14 Second fiber in weft direction 15 First layer of the rolling bearing cage 4a 16 Second layer of the rolling bearing cage 4a 17 First layer of the rolling bearing cage 4b 18 Second layer of the rolling bearing cage 4b 19 Third layer of the rolling bearing cage 4b 20 Fourth layer of the rolling bearing cage 4b 21 First layer of the rolling bearing cage 4c 22 Second layer of the rolling bearing cage 4c 23 First layer of the rolling bearing cage 4d 24 Second layer of the rolling bearing cage 4d 25 Third layer of the rolling bearing cage 4d 26 First layer of the rolling bearing cage 4e 27 Second layer of the rolling bearing cage 4e 28 Third layer of the rolling bearing cage 4e 29 Fourth layer of the rolling bearing cage 4e 30 Fifth layer of the rolling bearing cage 4e 31 First layer of the rolling bearing cage 4f 32 Second layer of the rolling bearing cage 4f 33 Third layer of the rolling bearing cage 4f 34 Fabric of the rolling bearing cage 4f 35 Guide surface on the bearing outer ring FS leadership game R rotation axis

Claims

[1] Rolling bearing cage (4, 4d - 4f) with two parallel side rings (9, 10) and a plurality of webs (11) connecting these two side rings (9, 10), wherein the side rings (9, 10) and two immediately adjacent webs (11) each form a cage pocket (6) for receiving a rolling element (5), wherein the side rings (9, 10) and the webs (11) form a one-piece body, and wherein the body consists of a fiber-reinforced plastic matrix, the body having several layers (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33), wherein these layers (15 - 33) have a common matrix material in which different fiber arrangements are embedded, wherein the fiber arrangements differ from each other in their material and / or structure and wherein one layer (16, 20, 22) has a fiber reinforcement which has increased stiffness compared to other layers,characterized by , that the individual layers (23 - 33) of the body are arranged axially next to each other. [2] 1. Rolling bearing cage (4, 4d - 4f) with two parallel side rings (9, 10) and a plurality of webs (11) connecting these two side rings (9, 10), wherein the side rings (9, 10) and two immediately adjacent webs (11) each form a cage pocket (6) for receiving a rolling element (5), wherein the side rings (9, 10) and the webs (11) form a one-piece body, and wherein the body consists of a fiber-reinforced plastic matrix, the body having several layers (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33), wherein these layers (15 33) have a common matrix material in which different fiber arrangements are embedded, wherein the fiber arrangements differ from each other in their material and / or structure and wherein one layer (16, 20, 22) has a fiber reinforcement which has increased stiffness compared to other layers, characterized by , that the layers (15 - 33) of the body are arranged radially on top of each other and axially next to each other. [3] Rolling bearing cage (4, 4d - 4f) according to one of claims 1 or 2, characterized by , that a layer (15, 16, 17, 20, 21, 22) of the body, the surface of which comes into contact with a guide surface (35) on a bearing outer ring (2) or on a bearing inner ring (3), has a fiber reinforcement which has a lower coefficient of sliding friction compared to other layers. [4] Rolling bearing cage (4, 4d - 4f) according to one of claims 1 to 3, characterized by , that one layer (15 - 33) of the body has a fiber reinforcement with increased tensile strength compared to other layers. [5] Rolling bearing cage (4, 4d - 4f) according to any one of claims 1 to 4, characterized by, that a first fiber reinforcement is formed as a reinforcing fabric (12) which is composed of identical fibers in the circumferential and axial directions. [6] Rolling bearing cage (4, 4d - 4f) according to any one of claims 1 to 5, characterized by , that a second fiber reinforcement is formed as a mixed reinforcement fabric (34) which is made up of one or more types of fibers in the circumferential direction and / or in the axial direction. [7] Spindle bearing, designed as a high-speed angular contact ball bearing, for supporting a spindle, designed for supporting a main spindle in a machine tool, with a rolling bearing cage (4, 4d – 4f) which is designed according to one of the preceding claims.

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