DE102022118825A1 - roller bearing - Google Patents

Abstract

The present invention relates to a rolling bearing (1), a rolling bearing arrangement (20) with a rolling bearing (1) and a method for producing a rolling bearing (1), with an outer ring (2), an inner ring (4) and on Outer and on the inner ring (2, 4) provided raceways (3, 5) rolling rolling elements (7). The outer ring (2) has an axial outer side (10, 11) and a radially outer side (9) and the inner ring (4) has an axial outer side (15, 16). The outer ring (2) or the inner ring (4) has a directly connected insulation (12) made of thermoset, the insulation (12) radially overlapping an axial outer side (10, 11, 15, 16). A thrust washer (17) is connected directly to the thermoset in the direction of an axial outer side (10, 11, 15, 16) and is thereby electrically insulated from the respective outer or inner ring (2, 4).

Description

The invention relates to a rolling bearing, comprising an outer ring, an inner ring and rolling bodies arranged between them and rolling on raceways provided on the outer and inner ring, as well as a rolling bearing arrangement and a method for producing a rolling bearing.

Such rolling bearings are used in a wide variety of areas. One example is the use in electric motors, which are also used in a wide variety of cases, increasingly in the automotive sector, for example, as drives for partially electric or fully electric driving. Among other things, rolling bearings are used to pivot the rotor, which usually rotates at high speed, which is why high-speed bearings are usually used, so-called high-speed motor bearings (HSMB). When operating electric motors, bearing damage can sometimes occur due to current flow through the rolling bearing. Such a current passage results, for example, from circular currents in the electric motor. As a result of the passage of current, lightning discharges can occur within the rolling bearing, which can cause damage to the raceways on which the rolling elements, which can be balls or rollers or similar, roll. In extreme cases, the damage can be so severe that bearing failure occurs. In order to avoid the passage of current, it is known to provide the rolling bearing with an insulation level, as in the JP3705219B2 so that no current can pass through due to this electrical insulation. It is known to design the rolling bearings as ceramic bodies, usually ceramic balls, which means that the rolling bodies themselves form the insulation level. Alternatively, it is also known to cover one of the rings with an oxide ceramic layer, which also has an insulating effect. However, these bearing designs are very complex and expensive to produce.

The invention is therefore based on the problem of specifying a rolling bearing that is improved in comparison.

To solve this problem, a rolling bearing of the type mentioned at the beginning is characterized in that it has an outer ring, an inner ring and rolling bodies arranged between them and rolling on raceways provided on the outer and inner ring. The outer and inner rings each have an axial outer side, with at least the outer ring or the inner ring having a directly connected insulation made of thermoset and this insulation radially overlapping at least one axial outer side of a bearing ring, i.e. the outer ring and the inner ring. On at least one of these axially outer sides, a thrust washer is connected directly to the thermoset, so that it is electrically insulated from the respective outer or inner ring.

In general, technical attempts are made to keep the manufacturing effort of bearing components as well as the associated manufacturing risks and manufacturing tolerances as low as possible. In order to be able to achieve high installation precision, the axial contact area of insulated bearings to other machine elements is either left out in the injection molding process or subsequently reworked. During assembly, standard parts, such as spacers or pieces, or reworked special elements are placed on the blank or reworked axial outer side, depending on the required accuracy, to ensure the required accuracy. In contrast, according to the invention, a solution that is complex and, from a manufacturing point of view, significantly more complex and therefore absurd is used to provide a bearing that is easy to assemble.

The inventors' elements are described in more detail following the mention in the claim sentence.

Rolling bearings are used for the rotatable mounting of machine parts, elements and assemblies and, to reduce friction, have rolling bodies which roll between the inner ring and the outer ring and thus reduce the friction in the rotatable bearing. As already stated above, the rolling bearing has an inner ring and an outer ring. Alternatively, the rolling bearing also has more than just one inner and/or outer ring. In addition, the bearing rings are alternatively divided and each have a raceway or a portion of a raceway. One or more outer raceways are usually formed on the inner ring and accordingly one or more inner raceways on the outer ring. The rolling elements rolling on the raceways are either balls or rollers. The balls or rollers are often guided and held in cages. Rolling bodies of a rolling bearing are either arranged one behind the other in a row in the circumferential direction or alternatively the rolling bearing has several rows of rolling bodies arranged next to one another. Alternatively, rolling bearings are also axial bearings. In this case, both the inner ring and the outer ring are the axial disks, which have axial raceways. Such bearings can be protected with seals against external contamination or against lubricant leakage from inside the bearing.

The outer and inner rings of a rolling bearing each have an axial on each axial end side outer side, which is also referred to as the flank.

In addition, outer rings have a radially outer side, which in the case of radial rolling bearings usually transmits the radial forces and, depending on the design, also axial forces to another machine element, for example a housing.

In the rolling bearing according to the invention, insulation made of a thermoset, i.e. a plastic, is used, which is applied to the outer circumference, i.e. the radially outer side of the outer ring and its axially outer sides or the inner circumference, i.e. the radially inner side of the inner ring and its axially inner sides applied, preferably sprayed on. This insulating layer has sufficient electrical insulation properties so that it can reliably prevent current from passing through the rolling bearing. A suitable resin can be used as the thermoset, for example an epoxy resin or a formaldehyde resin or materials based on this.

The connection of metallic materials in injection molding represents a particular challenge. In order to ensure ideal adhesion of the thermoset to the thrust washer or the thrust washer to the thermoset, the thrust washer of the bearing preferably has at least one element or characteristic To improve the connection of the thermoset to the metallic thrust washer.

In order to further ensure that displacement or rotation of the thrust washer on the bearing ring is prevented, the rolling bearing has positive locking elements in a further advantageous embodiment.

In a particularly preferred embodiment, the two aforementioned features are combined in one approach. For this purpose, a knurl is provided on the contact surface of the thrust washer in the direction of the bearing ring in later contact with the thermoset. On the one hand, this increases the contact area between the thermoset and the metal substrate, which results in a larger adhesion area, and on the other hand, a positive connection is created between the pane and the thermoset.

Furthermore, it is preferred to implement the positive locking elements of the thrust washer as recesses located on the circumference of the thrust washer. It is conceivable to design these recesses in a wide variety of geometries. When designed as semicircular openings, particularly low notch effects can be ensured in the metallic structure of the thrust washer.

In a further preferred embodiment, the thrust washer has a surface coating to improve the adhesion of the thermoset. Significantly higher adhesion was found than on a bare metal surface. This is particularly effective in combination with the preferred embodiments mentioned above.

In order to be able to achieve particularly good axial positioning of the rolling bearing, a thrust washer is connected to both axially outer sides of the outer ring or to both axially outer sides of the inner ring of the rolling bearing.

Basically, rolling bearings are designed in such a way that both the outer ring and the inner ring are each connected to a machine element in a rotationally fixed manner. If the outer ring is provided with thermoset, it was found that the connection between the thermoset and the outer ring can loosen during operation due to thermal expansion or the different coefficient of thermal expansion between the thermoset and the metal. In order to be able to ensure a rotationally fixed fit or prevention of axial movement despite this finding, in a further particularly preferred embodiment, positive locking elements are provided on the radially outer side of the outer ring to improve the adhesion of the thermoset to the outer ring. These can be designed in a wide variety of forms, for example as grooves, contours, knurls.

The invention further relates to a method for producing an outer or inner ring provided with thermoset plastic with a connected thrust washer for a rolling bearing of the type described above.

First, an outer or inner ring is provided for the rolling bearing. This can already be finished according to the requirements in the area of the raceway or simply represent a blank for subsequent finishing. A thrust washer is provided below. The outer or inner ring is then inserted into an injection molding tool. In the next step, the thrust washer is positioned so that a distance from the outer or inner ring is ensured in order to be able to insert the electrically insulating thermoset between the thrust washer and the bearing ring. It is also conceivable to provide the thrust washer completely or partially with a plastic layer in the contact area with the inner ring or the outer ring in an upstream injection molding process and to simply attach the thrust washer to its outer circumference using thermoset plastic the. This is followed by overmolding the outer or inner ring with thermoset and connecting the thrust washer with thermoset in the same process step. If necessary, further and final processing of the bearing ring(s) is carried out before an assembly step.

The invention also relates to a rolling bearing arrangement with a rolling bearing of the type described above. This has a first and a second machine element, wherein the outer or inner ring on the first or second machine element is secured against axial displacement and the remaining outer or inner ring is biased against the first or the second machine element with a biasing element against the thrust washer. The first machine element can be designed, for example, as a housing and the second machine element as a shaft. The thrust washer forms the ideal contact surface between the preload element and the bearing ring. The biasing element can be designed in any form, for example as a spring, spring ring, spring element or as an elastomer ring.

• 1 eine Darstellung eines Wälzlagers in der Seitenansicht,
• 2 eine dreidimensionale Darstellung des Lagers aus 1 in Schnittdarstellung,
• 3 eine Schnittdarstellung des Lagers aus 1,
• 4 den Verfahrensablauf zur Herstellung eines erfindungsgemäßen Lagers,
• 5 eine Wälzlageranordnung mit einem Lager in einer schematischen Axialschnittansicht.

The invention is explained below using exemplary embodiments with reference to the drawings, which are to be viewed as explanatory and not restrictive. The drawings are schematic representations and show:

• 1 a representation of a rolling bearing in a side view,
• 2 a three-dimensional representation of the warehouse 1 in sectional view,
• 3 a sectional view of the warehouse 1 ,
• 4 the process sequence for producing a bearing according to the invention,
• 5 a rolling bearing arrangement with a bearing in a schematic axial section view.

1 shows a rolling bearing 1 according to the invention, comprising an outer ring 2 and an inner ring 4 and rolling bodies 7 arranged between them and rolling on raceways 3, 5 provided on the outer ring 2 and on the inner ring 4. The outer ring 2 has an axial outer side 10, 11 and a radial one outer side 23, the inner ring 4 has an axial outer side 15, 16. The outer ring 2 or the inner ring 4 have a directly connected insulation 12 made of thermoset, the insulation 12 having an axial outer side 10, 11 of the outer ring 2 or an axial outer side 15, 16 of the inner ring 2 radially at least partially overlapped. The thrust washer 17, in 1 shown as an example on the outer ring 2, is connected directly to the insulation 12 made of thermoset plastic in the direction of the axially outer side of the outer ring and is thereby electrically insulated from the outer ring. Of course, this is conceivable in an analogous form on the other side of the bearing, as well as on the inner ring. 1 also shows elements 18 to improve the connection of the thrust washer to the thermoset. These elements can at the same time serve as a positive locking element 19 to prevent rotation and can be designed as recesses 21 located on the circumference of the thrust washer 17.

2 clarifies the features of the warehouse using a three-dimensional representation 1 in sectional view.

3 shows a sectional view of the warehouse 1 . The radial positive locking elements 22 provided in a preferred embodiment are shown, for example as grooves running around the circumference. These radial form-fitting elements 22 serve, for example, to avoid so-called annular migration of the bearing ring 2 or the bearing in the area of the insulation 12 when there are temperature changes, as well as to improve the adhesion of the thermoset.

1. a) Bereitstellung eines Außen oder Innenrings 2, 4 Dabei wird ein Ringrohling oder optional ein fertig bearbeiteter Außen- oder Innenring 2, 4 dem Verfahren zugrunde gelegt.
2. b) Bereitstellung einer Anlaufscheibe 17 Im Folgeschritt wird eine Anlaufscheibe 17 bereitgestellt. Diese kann unterschiedlichste Charakteristika, wie Formschlußelemente, Elemente zur Haftungsverbesserung oder Beschichtungen, aufweisen.
3. c) Einlegen des Außen oder Innenrings 2, 4 in ein Spritzgießwerkzeug Im Weiteren wird der Außen oder Innenring 2, 4 in das Spritzgießwerkzeug eingelegt, bzw. positioniert und fixiert.
4. d) Positionierung der Anlaufscheibe 17, beabstandet von dem Außen oder Innenring 2, 4 oder in einem vorgeschalteten Spritzprozess im Kontaktbereich mit Außen oder Innenring (2, 4) zumindest teilweise bereits mit einer Kunststoffschicht versehen. Die im Verfahrensschritt b) bereitgestellte Anlaufscheibe 17 wird in einer Position, beabstanded zum vorliegenden Außen oder Innenring 2, 4 positioniert, sodass diese das Ausfüllen des entstehenden Zwischenraums zwischen axialer Außenseite des Rings und Anlaufscheibe mit Duroplast zur Realisierung einer isolierenden Zwischenschicht ermöglicht. Es ist denkbar, die Anlaufscheibe in einem vorgeschalteten Spitzprozess bereits im Kontaktbereich mit Innenring 2 oder Außenring 4 zumindest teilweise mit einer Kunststoffschicht zu versehen.
5. e) Umspritzen des Außen oder Innenrings 2, 4 sowie Anbinden der Anlaufscheibe 12 mit Duroplast in einem Prozessschritt Sodann erfolgt der Spritzgießprozess, in dem der Duroplast eingespritzt wird und eine Verbindung zwischen dem vorliegenden Außen oder Innenring 2, 4 schafft.
6. f) Optional Weiterbearbeitung und Montage Der vorliegende Verbund aus Außen oder Innenring 2, 4, Duroplast und Anlaufscheibe 17 kann im weiteren Verfahren weitebearbeitet werden. Dabei sind jegliche mechanische Verfahren wie beispielsweise Drehen, Fräsen oder Hohnen, denkbar. Im Anschluss wird der Lagerring mit den weiteren Teilen zu einem Lager montiert.

4 shows schematically a possible process sequence for producing a rolling bearing 1 described above. The process consists of the steps:

1. a) Provision of an outer or inner ring 2, 4 The process is based on a ring blank or optionally a finished outer or inner ring 2, 4.
2. b) Provision of a thrust washer 17 In the following step, a thrust washer 17 is provided. This can have a wide variety of characteristics, such as positive locking elements, elements to improve adhesion or coatings.
3. c) Inserting the outer or inner ring 2, 4 into an injection molding tool. Furthermore, the outer or inner ring 2, 4 is inserted into the injection molding tool, or positioned and fixed.
4. d) Positioning of the thrust washer 17, spaced from the outer or inner ring 2, 4 or already at least partially provided with a plastic layer in an upstream injection molding process in the contact area with the outer or inner ring (2, 4). The thrust washer 17 provided in method step b) is positioned in a position spaced from the existing outer or inner ring 2, 4 so that it fills the resulting gap between axial outside of the ring and thrust washer with thermoset to create an insulating intermediate layer. It is conceivable to at least partially provide the thrust washer with a plastic layer in the contact area with the inner ring 2 or outer ring 4 in an upstream sharpening process.
5. e) Injection molding around the outer or inner ring 2, 4 and connecting the thrust washer 12 with thermoset in one process step. The injection molding process then takes place in which the thermoset is injected and creates a connection between the existing outer or inner ring 2, 4.
6. f) Optional further processing and assembly The present composite of outer or inner ring 2, 4, thermoset and thrust washer 17 can be further processed in the further process. Any mechanical processes such as turning, milling or honing are conceivable. The bearing ring is then assembled with the other parts to form a bearing.

5 shows a rolling bearing arrangement 20 with an aforementioned bearing in a schematic axial sectional view and represents a possible arrangement for using the rolling bearing 1. The rolling bearing arrangement 20 comprises a rolling bearing 1, as well as a first and a second machine element 13 and 14. The illustration shows an embodiment of the Rolling bearing 1 shown, which has a thrust washer 17 on both axial sides 10, 11 of the outer ring. The first machine element 13 can be designed as a housing and the second machine element 14 as a rotating shaft. In the illustration, the inner ring 4 is secured on the second machine element 14 against axial displacement. This can be done, for example, on one axial side by means of a shaft shoulder 26 and on the axially opposite side by means of a snap ring 23. The outer ring 2 is biased against the first machine element 21 with a biasing element 24 against the thrust washer 17 and a housing shoulder 25. The biasing element 24 can be designed differently, for example as a spring, spring ring, spring element or as an elastomer ring.

Reference symbol list

1

roller bearing

2

Outer ring

3

career

4

Inner ring

5

career

6

-

7

rolling elements

8th

-

9

radial outer side

10

axial outer side of the outer ring

11

axial outer side of the outer ring

12

insulation

13

first machine element

14

second machine element

15

axial outer side of the inner ring

16

axial outer side of the inner ring

17

thrust washer

18

Elements to improve connectivity

19

Positive locking elements

20

Rolling bearing arrangement

21

recesses

22

radial positive locking elements

23

snap ring

24

Prestressing element

25

Case heel

26

Wave paragraph

27

Axis of rotation

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 3705219 B2 [0002]

Claims (10)

Rolling bearing (1), comprising an outer ring (2), an inner ring (4) and rolling bodies (7) arranged between them and rolling on raceways (3, 5) provided on the outer and inner ring (2, 4), the outer ring ( 2) has an axial outer side (10, 11) and a radially outer side (9) and wherein the inner ring (4) has an axial outer side (15, 16) and the outer ring (2) or the inner ring (4 ) has a directly connected insulation (12) made of thermoset, the insulation (12) radially overlapping an axial outer side (10, 11, 15, 16), characterized in that a thrust washer (17) in the direction of an axial outer side ( 10, 11, 15, 16) is connected directly to the thermoset and is thereby electrically insulated from the respective outer or inner ring (2, 4). Rolling bearing (1). Claim 1 , characterized in that the thrust washer (17) has at least one element (18) in order to improve its connection to the insulation (12) made of thermoset. Rolling bearing (1). Claim 1 , characterized in that the thrust washer (17) has positive locking elements (19) to prevent displacement or rotation. Rolling bearing (1). Claim 2 , characterized in that the elements (18) to improve the connection of the thrust washer (17) to the thermoset or the positive locking elements (19) are designed as knurls. Rolling bearing (1). Claim 3 , characterized in that the positive locking elements (19) of the thrust washer (17) are designed as recesses located on the circumference of the thrust washer (17). Rolling bearing (1) according to one of the preceding claims, characterized in that the thrust washer (17) has a surface coating to improve adhesion with the thermoset. Rolling bearing (1) according to one of the preceding claims, characterized in that there is a thrust washer (17) on both axially outer sides (10, 11) of the outer ring (2) or on both axially outer sides (15, 16) of the inner ring (4). ) is directly connected. Rolling bearing (1) according to one of the preceding claims, characterized in that positive locking elements are provided on the radially outer side (10, 11) of the outer ring (2) to improve the adhesion of the thermoset to the outer ring (2). Method for producing a rolling bearing (1) according to one of the preceding claims with the method steps: a) Provision of an outer or inner ring (2, 4) b) Provision of a thrust washer (17) c) Inserting the outer or inner ring (2, 4) into an injection molding tool d) Positioning the thrust washer (17), spaced from the outer or inner ring (2, 4) or in an upstream injection molding process in the contact area with the outer or inner ring 2, 4, at least partially already provided with a plastic layer. e) Injection molding of the outer or inner ring (2, 4) and the thrust washer (17) with thermoset in one process step f) Optional further processing and assembly Rolling bearing arrangement (20) comprising a rolling bearing (1) according to one of the preceding claims, as well as a first and a second machine element (13, 14), wherein the outer or inner ring (2, 3) on the first or second machine element (13, 14) is secured against axial displacement and the remaining outer or inner ring (2, 3) is prestressed against the first or second machine element (13, 14) with a prestressing element (24) against the thrust washer (17).

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