DE102011122145A1 - Rolling element assembly useful for rotational connection with ball-rolling element raceway system, comprises overlap region at initial- and end region of hardened rolling body raceway, where overlap region has region of lesser hardness - Google Patents

Abstract

Rolling element assembly for rotational connection with tapered roll shaped rolling elements (2), preferably a ball-rolling element raceway system (1), comprises at least one overlap region at the initial- and end region of the hardened rolling body raceway, which extends along the rolling body raceway. The overlap region has a region of lesser hardness than the hardened region surrounding the overlap region, which includes a non-hydrogenated and/or annealed region, preferably a hardness gap region, which extends inclined or obliquely, preferably non-linearly through the overlap region. Rolling element assembly for rotational connection with spherical-, cylindrical roll-, barrel roll-, or tapered roll shaped rolling elements (2), preferably a ball-rolling element raceway system (1), or a roll/ball combination raceway system, for relative adjustment of many rotating bodies (3) mounted on- or against each other, preferably two bearing rings mounted on- or against each other, or many consecutive bearing ring segments or segmented rings, where at least one rolling body raceway is hardened along its ring shape in a contact region between the rolling element and bearing ring, using induction or induction hardening, comprises at least one overlap region at the initial- and end region of the hardened rolling body raceway, which extends along the rolling body raceway. The overlap region has a region of lesser hardness than the hardened region surrounding the overlap region, which includes a non-hydrogenated and/or annealed region, preferably a hardness gap region, which extends inclined or obliquely, preferably non-linearly through the overlap region.

Description

The invention relates to a rolling element arrangement for a rotary joint for the purpose of relative adjustment of several, at least two, mutually supported rotary body, in particular bearing bearings mounted against each other, wherein at least one Wälzkörperlaufbahn is hardened along its annular shape in the contact area between rolling elements and rolling bearing ring, according to the preamble of the main claim. Characterizing the invention is an overlap region at the beginning and end of the respective rolling element raceway according to characterizing part of the main claim and according to the independent claims.

Current state of the art provides for rolling bearing rings before a hardening of the raceways, as among other things, the load capacity, and consequently the life of a rolling element assembly for a rotary joint is increased. According to the prior art, on the one hand continuous hardening furnaces are known, in which the workpieces to be through-hardened, for example roller bearing rings, pass through a device in the longitudinal direction and thereby are heated, whereby only certain partial areas of the respective rolling bearing ring are hardened. One of the most common hardening methods used for race hardening is induction hardening. In this method, inductors or induction heads are moved relative to a ring to be hardened or relative to a raceway to be hardened or a partial point of the rolling bearing ring.

The patent document DE 10 2007 014 637 has such a device for inductive heating at least of peripheral layers of an annular workpiece. The inductors or induction heads are at least spatially variable with each other at least in terms of their radial distances.

Also the WO2010007635 ( PCT / IT2008 / 000475 ) and the EP1988179 have methods and devices with which partial areas or raceways of Wälzkörperringen can be inductively hardened. At least two inductors or induction heads are used, which are mounted at a preset distance from the surface to be hardened, while the workpiece to be hardened and the inductor move relative to one another. Finally, the disclosure further DE 10 2005 006 701 a method for producing a bearing ring for slewing bearings, which works on a fundamentally similar principle.

For the installation of the rotary joints in practice also plays the so-called "hardness" a partly important role. This hardness slug refers to the impact point between the beginning and the end of the runway hardening. This point is in practice that point which was not or hardly hardened during the hardening process of the track, in particular during the induction hardening process. Almost all rolling element arrangements according to the state of the art of this technology have such a hardness-slipping area.

This site is therefore therefore usually of lower hardness than the surrounding, hardened material. Less hard tracks are for the rolling behavior of the rolling elements usually associated with disadvantages, since the load capacity is less in less hard career sections than at the hardened raceway sections.

In addition, many Wälzkörperanordnungen, in particular ball slewing, for example, in four-point bearing, via holes with which the raceway system with rolling elements, in particular ball rolling elements, can be filled. These holes are provided with appropriately fitted, corresponding to the Bohrlohdurchmesser filling plug and sealed. The region of the filling bore and the associated filling stopper also represents a weak point of the raceway system, since the carrying capacity is lower in that region of raceway sections than on the hardened raceway sections.

In practice, one tries to mitigate the two disadvantages mentioned by the fact that in place of the hardening slipper and those holes for inlet and outlet of the rolling elements in and out of the raceway system close together, so instead of two places with lower carrying capacity in Laufbahnsysten only one such place is given. In the practice of ball slewing, for example in four-point bearings, the location of the hardness is thus also characterized by the filler for a hole through which the rolling elements are pushed when filling the raceway system and removal from the track system. This hole usually has a slightly larger cross-section than the rolling elements of the raceway system itself. In some rolling element arrangements, for example in roller slewing rings, no such filling holes are required.

In practice and according to the state of the art, this region of the hardness slack follows an imaginary line which extends from the center of the roller bearing ring and extends radially. The area of the hardness slug thus marks the beginning and the end of the hardened area of a rolling bearing ring.

In all currently used systems for (inductive) heating of portions of an annular workpiece, even in all the above-mentioned systems for particular inductive Heating the Wälzkörperlaufbahnen a rolling bearing ring, the at least one inductor or induction head is perpendicular to the rolling body to be cured, so that at the beginning and at the end of each inductively hardened zone results in a nearly exactly radially extending to the raceway Härteschlupf area. The hardened area, as well as the hardened area, is parallel to the plane which is circularly traversed by the inductor or induction head during the hardening process. Hardness zone and hardened zone thus always result on the same workpiece surface / Wälzkörperlaufbahn.

This range of hardness may range between one and more than fifteen millimeters, in some cases even significantly more, sometimes up to 100 or 200 millimeters, and depends on the rolling element size, the machine setting and the operation of the inductive hardening device or induction hardening machine. In some cases, induction hardening machines are equipped with incremental encoders, which allow the hardening to begin at, for example, 0 ° and end at, for example, 359 °, so that the inductor or induction head always passes through a non-360 ° circle segment. As a rule, attempts are made to keep this hardness range as low as possible, since this represents an area of lower hardness and thus an area of lower loading capacity, which is usually back-ground or must be back-ground. That back grinding causes another process step, which means more effort.

A disadvantage of the previous, conventional systems for inductive hardening Wälzkörperringen is that the above almost exactly radially to the track extending hardness slippage area in practice, especially when overrunning the generally hardened rolling elements on this hardness range, negative behaves. Consequently, even hardened by conventional systems for inductive hardening rolling bearing rings in the hardness zone are disadvantageous compared to the hardened areas.

On the one hand, the load-bearing capacity of a conventionally inductively hardened rolling bearing ring in the area of hardening slippage is reduced compared with the remaining part of the hardened raceway; second, this hardness slug area extends in exactly radially along an imaginary line from the center of the ring to the outside, so that an abrupt change of the running behavior of the rolling element results in the rotary joint, which just passes through the region of the hardness slippage, which provides for thirdly increased running noise of the entire rolling element assembly or rotary joint.

Considering these disadvantages, it is an object of the present invention to provide an improved rolling element arrangement which has improved running behavior with simultaneously increased load capacity in the beginning and end regions of the track hardening (s) with simultaneously reduced running noise of the rotary joint or rolling element arrangement, in particular in the beginning. and end areas of the track hardening (s) and in particular in the respective area of the hardening slippage.

A rolling element arrangement according to the invention for a rotary joint with ball, (cylinder) roller, tonnenrollen-, tapered roller or cross roller-shaped rolling elements, for example a ball rolling element raceway system, but preferably in particular a roller / ball combination runway system, in which several on or against each other Rotary body can be adjusted relative to each other and concentric. This applies, for example, to two bearing rings mounted on or against one another, but also, for example, to a plurality of ring segments or segmented rings mounted one on top of the other. The rolling element arrangement according to the invention. Is always designed so that at least one rolling element is present, which has hardened along its annular shape in the contact area between the rolling element and the rolling bearing ring, in particular by an induction or inductive hardening process has been cured.

The inductive hardening is formed according to the invention by a strong heating of the material to be hardened, which is usually present as a body made of tempered steel or bearing steel, to more than 600 ° C, in particular to over 800 ° C. By a subsequent quenching of the material by means of a suitable quenching medium, which is usually a liquid emulsion, such as a preparation of polyglycols, additives and water, the structure of the material / steel changes. It is on the one hand finely crystalline and the other harder. The main hardenable steel materials for rolling bearings are 25CrMo4 or 42rCrMo4, or C45N, and semi-precious steels, such as X20Cr13.

The raceway system according to the invention to be hardened can - depending on the shape and task - include different rolling elements. As rolling elements, which can be used in the arrangement according to the invention are basically ball, roller, ball-roller, barrel, cone, -shaped or cross-shaped roller-shaped or even pendulum-shaped rolling elements in question. The track system can also be designed as a combined bearing or combination system, for example as a roller / ball combination.

Advantageously, the hardening process for the track is to be designed so that the degree of hardness of the hardened raceway is about the hardness of the rolling elements used, or slightly lower, for example in the coarse range between 48 HRC and 65 HRC.

This inventively improved Wälzkörperanordnung is thus as a rotary joint for the purpose of relative adjustment of at least two on or against each other supported rotary body to understand, in particular two on or against each other mounted rolling bearing rings, wherein at least one Wälzkörperlauf cured along its annular shape in the contact area between rolling elements and rolling bearing ring, in particular by an induction - Was hardened or inductive hardening process.

Characterizing the invention is at least one overlapping region at the beginning and at the end of the at least one hardened rolling element raceway extending along this rolling element raceway, said overlapping region having a region of lesser hardness, referred to hereinbefore as a hardness slug, passing through the overlap region below a certain one Angle extends over the raceway normal. Under the track normal to understand is the imaginary line, which extends radially out of the circle center of the rolling bearing assembly, ergo from the axis of rotation of the rotary joint, radially towards the ring.

The raceway system can also be suitable for receiving cages or spacers, or for a Beabstandungskomponenten loose system, for example, for a full complement or vollkugelige rotary joint, be suitable. Particularly advantageous in the context of the invention is an inclined between 0 ° and 90 ° Härteschlupf area, preferably inclined at an angle to track normal of greater than 5 ° and less than 85 °. As a practice-relevant and good to produce preferably angles have proven to runway normal of about 45 °.

This angular "inclination" is achieved, for example, by the fact that special inductors or induction heads are not placed exactly radially to Wälzkörperring during the inductive hardening process, so are not exactly rectified or employed parallel to the aforementioned career standards, but at said inclination angle. As a result, the region of lower hardness does not extend exactly radially over the hardened rolling bearing body or rolling bearing ring, but rather in an inclined manner over the hardened rolling bearing body or rolling bearing ring, for example in a spur-shaped or band-like manner by the above-described overlapping region.

In a further embodiment of the invention, the inclined course of the Härteschlupf area is not exactly linear, but may follow a freeform or curve shape or arcuate shape, or even a combination of freeform and / or curve shape and / or arch shape, optionally with existing straight sections, consequences. In any case, however, the course will basically extend obliquely or beveled over the overlap area.

In a further continuing embodiment of the invention, the overlapping region can be located near the at least one filling plug hole introduced into the rotary body or be congruent to this filling plug bore area or at least overlap or penetrate this area of the filling plug bore.

When multiple raceways are hardened, multiple overlap areas and areas of hardness slippage are created - typically, and preferably one hardness zone per cured track. According to the invention, a respective overlapping area and hardness-slipping area is always located between the beginning and the end of the respective track hardening.

According to the invention, the at least one overlap region accordingly, in each case at least one region of lower hardness, so-called Härteschlupf area, compared to the respective directly surrounding hardened track area, said area of lower hardness is fully or partially processed, so that also a spur-shaped or band-like relief area can result. As a particularly advantageous, a subsequent machining, for example, a regrinding or a Hinterschliefen has proven.

Consequently, said undercut area can overlap or overlap with the area of the hardness zone in whole or in part. According to the invention, at least one overlap region with a region of lesser hardness can be introduced into each raceway of the rolling element arrangement.

Because of the raceway design, a consequence of the invention is that the run-off zones or run-out regions of the hardened regions, in particular the run-out regions of the hardness zones, are inclined in the overlapping region at a certain angle with respect to the raceway normal. These angles of inclination may for example be very pronounced and be between 0 ° and 90 °, but preferably at an angle of greater than 5 ° and smaller than 85 °, have, but in particular be at an angle of about 45 °.

As a further sequence of the invention is to be imagined that in the operation of the rotary joint or Wälzkörperanordnung the rolling-over area rolling over rolling elements are supported there relief area mainly in the hardened area or the hardness zones and are supported.

In general, with regard to the invention, the hardening depth of the hardened area or hardening zone may be less than 20 mm, preferably less than 10 mm.

With regard to the relief area or the hardened area, it should be noted overall that the spur-shaped or band-like area of lesser hardness is narrower than 200 mm, preferably narrower than 50 mm.

Further advantages and embodiments will be apparent from the following examples by way of example. Here are an example:

1 a schematic radial section of a Wälzkörperlaufbahnsystems a ball slewing, designed as a four-point bearing with both sides indicated mounting options for connection structures and indicated sealing systems and (dashed lines) indicated plug filling bore

2 a perspective view of a rotary connection of a Wälzkörperlaufbahnsystems a combination of roller / ball with two axially about one above the other arranged raceways. The upper track system indicates a (cage-guided) roller slewing connection. The lower raceway system indicates a ball slewing connection (with spacers).

2a a partial section (detail / detail) as a schematic radial section of the rotary joint of a rolling body raceway system of a combination of roller / ball with two approximately axially superposed raceways. In particular, hardened areas on the raceways are indicated in dark color.

3 a plan view of the roller raceway (rolling element roller), which is present in the respective rolling bearing ring and roll on which roller rolling elements. It is pointed to a section. For simplicity, only the career is dargstellt. On details of the rolling element arrangement is omitted here.

3a a section of a plan view of the roller track (rolling element roller), which shows the inductively hardened area and the overlap area and the beginning and end of the track hardening. Also shown is a band or track-shaped area which has a slope at an angle ε.

4 a schematic view (detail / detail), greatly enlarged, a possible curve of hardness and hardness zone within the overlap region in the contact area between the rolling element and raceway.

1 shows, for example, a schematic radial section of a rolling body raceway system ( 1 ) a ball slewing connection, configured as a four-point bearing with fastening options for connecting structures indicated on both sides and seals located above and below the raceway system (US Pat. 6 ; 7 ) for the purpose of sealing the rolling element gap ( 8th ). as well as indicated filling plug bore ( 14 ). The rolling element track for the balls ( 16 ) is filled and emptied through that hole ( 14 ), which is closed by means of a Füllstopfens. This plug prevents foreign matter from entering and exiting the track system by closing the track system. The filling plug bore ( 14 ) has approximately the diameter of the rolling elements ( 2 ), but in practice is designed to be slightly larger. The rolling element track ( 16 ) is in both rotating body ( 3 ; 4 ) alike.

2 shows by way of example a perspective view of a rotary connection of a rolling body raceway system of a roller / ball combination (FIG. 15 ) with two axially about one above the other arranged raceways ( 16 ; 17 ). The upper raceway system ( 17 ) indicates a (cage-guided ( 18 )) Roller slewing connection. The lower raceway system indicates a ball slewing connection (with spacers ( 18 )) at. Both careers ( 16 ; 17 ) are inductively hardened in large parts. The rolling elements ( 2 ) are also hardened and roll over the raceways ( 16 ; 17 ). Shown is a rotary joint, which is an outer roller bearing ring ( 4 ) against an inner rolling bearing ring ( 3 ) can twist.

3 represents, for example, the top view of the track system of the roller ( 17 ), for simplicity only the (hardened) career is shown. A section ( 20 ) marks the overlap area ( 12 ) and also the beginning and end of the track hardening.

2a shows by way of example a partial section (detail / detail) as a schematic radial section of the rotary connection of a rolling body raceway system of a roller / ball combination (FIG. 15 ) with two approximately axially superimposed raceways. In particular, hardened areas on the raceways are indicated in dark color. In particular, hardened areas ( 9 ; 11 ) to the Careers ( 16 ; 17 ). The hardened areas extend up to a certain hardening depth ( 23 ) in the rolling bearing ring material. According to the invention, an inclined region of lower hardness results ( 22 ), which extends through outlet areas ( 10 ) of the hardened areas of the area of lower hardness ( 22 ) delimits. As a rule, the hardened area runs along a track ( 17 ) for roller rolling elements not to the end of the plane surface, but is spaced, thus runs at a distance ( 28 ) from the hardened area ( 9 ; 11 ) to the edge.

3a discloses an exemplary section ( 20 ) a plan view of the roller track ( 17 ) (Wälzkörperlaufbahn role), which the inductively hardened area ( 9 ; 11 ) as well as the overlap area ( 12 ). The raceway is in each case in the rolling bearing ring ( 3 ; 4 ) brought in. The hardened area is located in the middle of the track, so it is spaced from the edge ( 28 ). In particular, the hardened area ( 9 ; 11 ) of the career. The overlap area ( 12 ) defines the beginning and end of the at least hardened rolling element raceway ( 17 ), which extends along this rolling body track ( 17 ).

The light color opposite the dark color settling region indicates a region of lower hardness ( 22 ), in particular a range of hardness ( 22 ). This hardness slipper area ( 22 ) extends through the overlap area ( 12 ) at a certain angle (ε) with respect to the track normal ( 29 ). The career standard ( 29 ) is the imaginary line, which is radially out of the circle center of the rolling bearing assembly, thus from the axis of rotation ( 13 ) of the rotary connection extends radially in the direction of the ring. This angle (ε) is between 0 ° and 90 °, preferably greater than 5 ° and less than 85 °, in particular about 45 °. The area of lower hardness ( 22 ) extends, for example, in a spur-shaped or band-like manner through the overlapping region (FIG. 12 ).

3a further discloses, for example, that the hardness slug area ( 22 ) in the overlapping area ( 12 ), but also one or both sides more or partially reground or relief ground, so that a spur-shaped or band-like relief area ( 21 ), whereby this relief region ( 21 ) and hardened area ( 22 ) completely or partially overlap or overlap. The spur-shaped or band-like area of lower hardness ( 22 ) is usually narrower than 25 mm.

4 discloses schematically and by way of example a schematic view (detail / detail), greatly enlarged, of a possible course ( 24 ) of hardness zone and hardness ( 22 ) in the contact area between the rolling element and the raceway. Shown are hardening depth ( 23 ) and contact area ( 25 ; 26 ) of rolling elements and Wälzkörperlaufbahn. The hardening depth ( 23 ) of the hardened area ( 9 ) or the hardening zone ( 11 ) is usually less than 20 mm.

LIST OF REFERENCE NUMBERS

1

Rolling element track system ball

2

rolling elements

3

First rotatable body (rotating body), z. B .: rolling bearing ring

4

Second rotatable body (rotating body), z. B .: rolling bearing ring

5

upper or lower overlap area

6

sealing arrangement

7

sealing arrangement

8th

gap

9

hardened area

10

discharge area

11

Hardness zone of the hardened rolling element track

12

Area of overlap

13

Axis of rotation; Circle center

14

Stopper hole (indicated by dashed lines)

15

Rolling element track system combination roller / ball

16

Rolling element ball

17

Rolling element roller

18

Wälzkörperdistanzstück

19

Rolling Element

20

Cutting of rolling element roller

21

Relief-area

22

Area of lower hardness, z. B: hardness slippage area

23

hardening depth

24

Hardness progression symbolic

25

Contact area rolling element raceway

26

Contact area raceway rolling elements

28

Distance hardened area to edge

29

Track normal axis

30

Connecting line between upper and lower overlap area

ε

tilt angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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

• DE 102007014637 [0003]
• WO 2010007635 [0004]
• IT 2008/000475 [0004]
• EP 1988179 [0004]
• DE 102005006701 [0004]

Claims (16)

Rolling element arrangement for a rotary connection with ball, cylindrical roller, barrel roller or taper roller-shaped rolling bodies, for example a ball rolling track system ( 1 ), preferably also a roller / ball combination runway system ( 15 ), for the purpose of relative adjustment of several on or against each other mounted rotary bodies ( 3 ; 4 ), in particular two on or against each other mounted rolling bearing rings, for example even several mutually mounted ring segments or segmented rings, wherein at least one Wälzkörperlaufbahn ( 16 ; 17 ) along its ring shape in the contact area between rolling elements ( 2 ) and rolling bearing ring ( 3 ; 4 ), in particular hardened by an induction or inductive hardening process, characterized in that at least one overlapping region ( 12 ) at the beginning and end of the at least one hardened rolling element raceway ( 16 ; 17 ), which extends along this rolling body track ( 16 ; 17 ), this overlapping area ( 12 ) an area of lower hardness ( 22 ) as the hardened area surrounding it ( 9 ; 11 ), preferably an uncured and / or annealed region, in particular a hardness-slub region (US Pat. 22 ), which inclined or oblique, for example, non-linear, by the overlap region ( 12 ). Rolling element arrangement for a rotary joint according to claim 1, characterized in that the beginning and the end of the track hardening, in particular the starting area and the end area of the hardened area ( 9 ; 11 ) of a career ( 16 ; 17 ) along the raceway normal ( 29 ) cover, overlay or overlap. Rolling element arrangement for a rotary joint according to claim 1 or claim 2, characterized in that the hardening-slipping region ( 22 ) or the area of lower hardness ( 22 ) at a certain angle (ε) with respect to the track normal ( 29 ) is inclined between 0 ° and 90 °, preferably at an angle (ε) in relation to track normal ( 29 ) of greater than 5 ° and less than 85 °, in particular at an angle (ε) to raceway standards ( 29 ) of about 45 °. Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that the hardening-slipping region ( 22 ) or the area of lower hardness ( 22 ) in the direction of an imaginary connecting line ( 30 ) between the upper and lower overlapping areas ( 12 ), the actual course of this hardness ( 22 ) follows, at least in part, a freeform and / or a curve shape and / or an arch shape. Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that the hardening-slipping region ( 22 ) or the area of lower hardness ( 22 ) in the direction of an imaginary connecting line ( 30 ) between the upper and lower overlapping areas ( 12 ), the actual course of this hardness ( 22 ) includes at least an approximately straight section. Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that the area of lower hardness ( 22 ) spur-shaped or band-like through the overlapping area ( 12 ), for example following a free form and / or a curve shape and / or an arc shape, in particular includes at least one approximately straight section. Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that the at least one overlapping region ( 12 ) an area of lower hardness ( 22 ) as the directly surrounding area ( 9 ; 11 ), wherein that region of lower hardness ( 22 ) is wholly or partially eroded, for example, machined by machining, in particular reground or beveled, so that in particular a spur-shaped or band-like relief area ( 21 ). Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that the relief area ( 21 ) and area of lower hardness ( 22 ) or hardened area ( 22 ) close to each other, or even completely or partially along the raceway normal ( 29 ) overlap or overlap. Rolling element arrangement for a rotary joint according to claim 7 or 8, characterized in that the relief area ( 21 ) is wider than the area of lower hardness ( 22 ) or the hardening slipper area ( 22 ). Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that in each track ( 16 ; 17 ) of the rolling element arrangement at least one Ürlappungsbereich ( 12 ) with a region of lower hardness ( 22 ) given is. Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that the outlet areas ( 10 ) of the hardened areas ( 9 ), in particular the outlet areas ( 10 ) of the hardness zones ( 11 ), in the Overlap area ( 12 ) at a certain angle (ε) between 0 ° and 90 °, preferably at an angle (ε) of greater than 5 ° and less than 85 °, with respect to the track normal ( 29 ) are inclined. Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that the relief area ( 21 ) Rolling bodies ( 2 ) are there in the main of the hardened area ( 9 ) or the hardness zones ( 11 ) are supported and carried by them. Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that the hardening depth ( 23 ) of the hardened area ( 9 ) or the hardening zone ( 11 ) is less than 20 mm, preferably less than 10 mm. Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that the spur-shaped or band-like region of lower hardness ( 22 ) is narrower than 200 mm, preferably narrower than 50 mm. Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that at least one roller bearing ring ( 3 ; 4 ) of a tempered steel or bearing material, for example of a 25CrMo4 or 42rCrMo4 material, preferably also of C45N, in particular also of a semi-precious steel material, such as X20Cr13 exists. Rolling element arrangement for a rotary joint according to at least one of the preceding claims, characterized in that hardened regions ( 9 ; 11 ) have a Rockwell hardness between 48 HRC and 65 HRC and areas of lower hardness ( 22 ) have a Rockwell hardness of, for example, less than 48 HRC, or in particular the core hardness of the base material.

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