DE102009032961A1 - Rolling bearing cage - Google Patents

Abstract

Rolling bearing cage made of a fiber composite material, comprising a thermoplastic material with fibers embedded therein, the rolling bearing cage (1, 3) being produced by injection molding.

Description

Field of the invention

The The invention relates to a roller bearing cage of a A fiber composite material comprising a thermoplastic material with fibers embedded therein.

Background of the invention

Ball bearing cages this type are components of rolling bearings for high-speed rotating equipment, for example be used in medical technology. A typical field of application are Dental instruments using an air turbine is used to drive a rotor shaft, which is a dental Editing tool is located. The for the storage of Air turbine used bearings are at speeds of Operated 200,000 rpm to 500,000 rev / min, accordingly occur very high centrifugal forces, the extreme demands on put the used components and materials. About that In addition, such dental instruments become regular in autoclave at elevated temperature and pressure sterilized, whereby the rolling bearing also loaded becomes.

Next this application to a dental instrument Such rolling bearing cages and other maintenance-free Storages can be used, which are operated at very high speeds. In addition, rolling bearing cages come this Type also used in spindle bearings.

In the DE 197 42 939 A1 a bearing for a very high speed rotating assembly is described. There it is mentioned that rolling bearing cages may consist of polyimide resin or of phenolic resin with embedded fiber layer. In this construction, however, there is a risk that water is absorbed by the resin.

From the DE 38 90 466 T1 a rolling bearing cage is known, which consists of polyphenylene sulfide (PPS) resin and should have a good resistance to heat, oil and chemicals. In addition, other materials for the rolling bearing cage are proposed, for example polyamide, polyacetal, polybutylene terephthalate. These plastics can be used either alone or as a fiber composite material by being reinforced by glass fibers or carbon fibers (carbon fibers).

Even though Such rolling bearing cages for some time Time are used, their use is associated with some disadvantages. For example, have conventional rolling bearing cages no or only very poor emergency running properties, in particular with insufficient lubrication. Due to the high speeds it can in case of insufficient or missing lubrication after a short time to one Failure of the rolling bearing cage and thus the rolling bearing come. Likewise, the material properties by the already mentioned sterilization in an autoclave at temperatures of about 135 ° C at overpressure and in a steam atmosphere impaired. Finally, the high will be Price of conventional rolling bearing cages as considered disadvantageous.

Summary of the invention

Of the Invention is therefore the object of a rolling bearing cage specify from a fiber composite, which at very high speeds can be used and at the same time inexpensive to produce.

to Solution to this problem is in a rolling bearing cage of the type mentioned above provided according to the invention, that it is made by injection molding.

By the inventively provided injection molding the thermoplastic resin material having embedded therein Fibers, the rolling bearing cage can be particularly efficient and manufactured inexpensively. The inventive Rolling bearing cage is characterized by a good high temperature resistance, a low water absorption and a good dimensional stability out. In addition, the rolling bearing cage against organic and inorganic chemicals resistant. By inventively provided Production of rolling bearing cage by injection molding will receive a product that meets the very high demands on the Strength and temperature resistance met.

at the rolling bearing cage according to the invention can it may be provided that the plastic material is comprised of the group Polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyethersulfone (PES), Polyetherimide (PEI), and liquid crystal polymers (Liquid Chrystal Polymer, LCP). these plastic materials, which are also referred to as high performance plastics draw characterized by high melting temperatures, so that the good mechanical Properties even at temperatures above 200 ° C remain. Certain high performance plastics, for example PPS, are chemically resistant to almost all solvents, many acids and alkalis as well conditioned also to oxygen at high temperatures.

It is also within the scope of the invention that the roller bearing cage according to the invention consists of a plastic material, the at least one of mixtures include: PEEK and PES, PEEK and PPS, PEEK and PEI. The term PEEK is used in this application as a generic term for polyetheretherketones, which also include the following PEEK derivatives: PEK, PEEEK, PEEKEK, PEKEKK, PAEK or PEKK. These PEEK derivatives can also be used as plastic material for the roller bearing cage, either as a single plastic material or in a mixture, for example with PES, PPS or PEI. If a mixture of at least two different plastic materials is used, the material properties can be specifically influenced in order to adapt them to the technical requirements which the rolling bearing cage according to the invention has to fulfill.

at the rolling bearing cage according to the invention can the fibers from the group comprising glass fibers, carbon fibers (Carbon fibers), aramid fibers and PTFE fibers selected be. Each of these fibers has certain advantageous properties, for example show glass and to an even greater extent Carbon fibers have a high rigidity when combined with the thermoplastic Plastic material connected as a matrix to a fiber composite material are. Aramid fibers in turn have high toughness, so that the emergency running properties of the rolling bearing cage be improved. Similarly, increase PTFE fibers runflat as they act as a solid lubricant Act.

It are also embodiments of the invention Rolling bearing cage conceivable in which at least two different types of fibers are used. For example, you can Glass fibers could be combined with aramid fibers, as well Carbon fibers are combined with aramid fibers. Also one Combination of glass fibers with PTFE fibers is conceivable.

at the rolling bearing cage according to the invention can the proportion of fibers based on the mass of the rolling bearing cage 5 to 50%, it is particularly preferred if the proportion 10 to 20%.

According to one Further development of the rolling bearing cage according to the invention it can be provided that he at least one solid lubricant containing from the group comprising polytetrafluoroethylene (PTFE), Graphite and molybdenum disulfide. These Solid lubricants improve the emergency running properties, if that conventional lubricants, such as a grease or an oil, not available in sufficient quantity stands. Preferably, the proportion of the solid lubricant is related to the mass of the rolling bearing cage up to 30%, especially it is preferred if the proportion of the solid lubricant up to 15%.

at the rolling bearing cage according to the invention can the plastic material contains one or more fillers, the one selected from the following group or are: carbon black, graphite, nanoscale fillers the group of oxides, hydrated oxide, hydroxide, carbonate, nitrates or Nitrites of an element, wherein the element is selected from the group Boron, aluminum, barium, magnesium, calcium, gallium, indium, silicon, Germanium, tin, titanium, zirconium, zinc, yttrium or iron is.

Especially can in the rolling bearing cage according to the invention the nanoscale filler selected from the following group be: synthetic or natural phyllosilicates, clay minerals like allevardite, amesite, beidellite, bentonite, feldspar, fluorhectorite, Fluoro-vermiculite, mica, halloysite, hectorite, kaolin, montmorillonite, Muscovite, nontronite, palygorskite, saponite, sepiolite, smectite, stevensite, Talcum, vermicullite and synthetic talcum types, as well as from the alkali metal silicates Maghemite, Magadiite, Kenyaite, Makatite, Silinaite, Grumantite, Revdit and their hydrated forms and crystalline silicas.

alternative The nanoscale filler can be selected from the following group be selected: inorganic layer compounds such as hydrotalcites, Double hydroxides and heteropolyacids.

Of the Proportion of filler or fillers in the rolling bearing cage according to the invention until amount to 20% of the mass of the rolling bearing cage.

Short description of the drawing

1 shows a first embodiment of a rolling bearing cage according to the invention in a perspective view; and

2 shows a second embodiment of a rolling bearing cage according to the invention in a sectional view.

Detailed description the drawing

The in 1 shown rolling bearing cage 1 has an annular basic shape, in the circumferential direction are circular recesses 2 provided, in each of which a spherical rolling element can be held and guided. Such rolling bearing cages 1 are called window cages.

The in 1 shown rolling bearing cage 1 is made of polyetheretherketone (PEEK) with embedded glass fibers to form a fiber composite. The proportion by weight of the glass fibers is 10% in the illustrated embodiment. The rolling bearing cage 1 is made by injection molding. In addition, polytetrafluoroethylene (PTFE) as a solid lubricant with a weight fraction of 5% ent hold. Furthermore, the rolling bearing cage 1 Kaolin, titanium dioxide and aluminum oxide as nanoscale fillers in a weight ratio of 3%.

Of the Window cage is using thermoplastic injection molding produced by forced removal, which also allows complex geometries can be produced in a single process step, without a subsequent machining is required.

The in 2 shown roller bearing cage of the second embodiment has in accordance with the first embodiment, an annular basic shape and recesses 4 on. These recesses 4 are to one side of the rolling bearing cage 3 open, such cages are also referred to as a snap cage. the rolling bearing cage 3 consists of a blend of the plastic materials PEEK and PES (polyethersulfone). In addition, 10% carbon fibers and 10% aramid fibers, based on the mass of the rolling bearing cage 3 , contain. The rolling bearing cage 3 has for lubrication molybdenum disulfide as a solid lubricant in a proportion of 5 weight percent. The nanoscale fillers used are calcium carbonate and zinc sulfide in an amount of 5% by weight.

The rolling bearing cage 3 is produced in the thermoplastic injection molding process with forced removal, a subsequent machining is not required.

LIST OF REFERENCE NUMBERS

1

Rolling bearing cage

2

recess

3

Rolling bearing cage

4

recess

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19742939 A1 [0004]
• - DE 3890466 T1 [0005]

Claims (14)

Rolling bearing cage made of a fiber composite material, comprising a thermoplastic material with embedded fibers, characterized in that the rolling bearing cage ( 1 . 3 ) is made by injection molding. Rolling bearing cage according to claim 1, characterized in that the plastic material is selected from the group comprising polyetheretherketone (PEEK), polyphenylene sulphide (PPS), Polyethersulfone (PES), polyetherimide (PEI), and liquid crystal polymers (Liquid Chrystal Polymer, LCP) is selected. Rolling bearing cage according to claim 2, characterized in that it comprises a mixture of at least two includes various plastic materials. Rolling bearing cage according to claim 3, characterized in that the plastic material at least one of the following blends: PEEK and PES, PEEK and PPS, PEEK and PEI. Rolling bearing cage according to one of the claims 2 to 4, characterized in that at least one of the plastics a PEEK derivative, in particular PEK, PEEEK, PEEKEK, PEKEKK, PAEK or PEKK. Rolling bearing cage according to one of the preceding Claims, characterized in that the fibers the group comprising glass fibers, carbon fibers, aramid fibers and PTFE fibers are selected. Rolling bearing cage according to one of the preceding Claims, characterized in that it comprises at least two includes various types of fibers. Rolling bearing cage according to one of the preceding claims, characterized in that the proportion of the fibers based on the mass of the rolling bearing cage ( 1 . 3 ) Is 5 to 50%, preferably 10 to 20%. Rolling bearing cage according to one of the preceding Claims, characterized in that it comprises at least one Contains solid lubricant, which consists of the group Polytetrafluoroethylene (PTFE), graphite, and molybdenum disulfide, is selected. Rolling bearing cage according to claim 9, characterized in that the proportion of the solid lubricant based on the mass of the rolling bearing cage ( 1 . 3 ) is up to 30%, preferably up to 15%. Rolling bearing cage according to one of preceding claims, characterized in that the plastic material contains one or more fillers, the or those from the group comprising carbon black, graphite, nanoscale Fillers from the group of oxides, hydrated oxide, hydroxide, Carbonate, nitrates or nitrites of an element is selected or are, wherein the element from the group comprising boron, aluminum, Barium, magnesium, calcium, gallium, indium, silicon, germanium, Tin, titanium, zirconium, zinc, yttrium or iron is. Rolling bearing cage according to claim 11, characterized in that the nanoscale filler from the group consisting of synthetic or natural phyllosilicates, Clay minerals such as allevardite, amesite, beidellite, bentonite, feldspar, Fluorohectorite, fluoro vermiculite, mica, halloysite, hectorite, kaolin, Montmorillonite, muscovite, nontronite, palygorskite, saponite, sepiolite, Smectite, stevensite, talc, vermicullite and synthetic talc types, as well as from the alkali metal silicates Maghemit, Magadiit, Kenyait, Makatit, Silinaite, grumantite, revdite and their hydrated forms and crystalline silicas. Rolling bearing cage according to claim 11, characterized in that the nanoscale filler from the group comprising inorganic layer compounds such as hydrotalcites, Double hydroxides and heteropolyacids selected is. Rolling bearing cage according to one of claims 11 to 13, characterized in that the proportion of the filler or of the fillers based on the mass of the rolling bearing cage ( 1 . 3 ) is up to 20%.

Images