EP3320221A1

EP3320221A1 - Cylindrical roller bearing and method for producing a cylindrical roller bearing

Info

Publication number: EP3320221A1
Application number: EP16738663.0A
Authority: EP
Inventors: Reinhard Kick-Rodenbücher; Rainer Eidloth; Markus Mantau
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2015-07-09
Filing date: 2016-06-08
Publication date: 2018-05-16
Also published as: JP2018527520A; CN107850115A; WO2017005256A1; KR20180027409A; US20180363700A1; DE102015212829A1

Abstract

Cylindrical roller bearings have cylindrical rollers as rolling bodies. The cylindrical roller bearings can be configured as radial anti-friction bearings and transmit radial loads in this design. It is an object of the present invention to propose a cylindrical roller bearing and a method for producing it, with the result that the cylindrical roller bearing can be produced inexpensively and with sufficiently high quality. To this end, a cylindrical roller bearing (1) is proposed having an inner ring (3), having an outer ring (2) and having a plurality of cylindrical rollers (4), wherein the cylindrical rollers (4) are arranged between the inner ring (3) and the outer ring (2), wherein the outer ring (2) has an inner raceway (6) for the cylindrical rollers (4), a fixed rim section (7) and a flange rim section (9), and wherein the inner ring (3) has an outer raceway (10) for the cylindrical rollers (4), and wherein the inner raceway (6) and/or the outer raceway (10) are/is shaped into the final contour thereof by way of extrusion.

Description

Cylindrical roller bearing and method for manufacturing a Zylinderrollenlaqers

The invention relates to a cylindrical roller bearing with an inner ring, with an outer ring and with a plurality of cylindrical rollers, wherein the cylindrical rollers between the inner ring and the outer ring are arranged. The outer ring has an inner race for the cylindrical rollers, a Festbordabschnitt and a Bördelbordabschnitt, the inner ring has an outer raceway for the cylindrical rollers. Furthermore, the invention relates to a method for manufacturing the cylindrical roller bearing.

Cylindrical roller bearings have cylindrical rollers as rolling elements. The cylindrical roller bearings can be designed as radial roller bearings and transmit radial loads in this design. The raceways of the cylindrical roller bearings are formed as cylinder jacket surfaces coaxial and concentric with the respective axis of rotation of the cylindrical roller bearing. Usually, bearing rings for cylindrical roller bearings are made as solid rings, that is, starting from a solid semi-finished by means of separating, erosion and machining in particular machined. Such cylindrical roller bearings form the closest prior art.

In addition to the massive rings, a forming production of rings for bearings has already become known. Thus, US Pat. No. 2,267,229 discloses the production of rings by means of a forming step starting from a circular disk.

It is an object of the present invention to provide a cylindrical roller bearing and a method for its production, so that the cylindrical roller bearing can be manufactured inexpensively and with sufficiently high quality.

This object is achieved by the cylindrical roller bearing with the features of claim 1 and by the method having the features of claim 9. Preferred or advantageous embodiments of the invention will become apparent from the dependent claims, the following description and the accompanying drawings. The invention thus relates to a cylindrical roller bearing, which is in particular designed as a radial roller bearing, in particular with a pressure angle of 0 degrees. The cylindrical roller bearing has an inner ring and an outer ring, wherein the inner ring and the outer ring are arranged coaxially and / or concentrically with each other and to a main axis of rotation of the cylindrical roller bearing. Further, the cylindrical roller bearing comprises a plurality of cylindrical rollers, wherein the cylindrical rollers between the inner ring and the outer ring are arranged to roll.

The inner ring and the outer ring each have a raceway section, wherein the raceway section has a material thickness of preferably more than two millimeters and in particular more than three millimeters. Particularly preferred inner ring and / or outer ring are formed thick-walled. The cylindrical rollers are preferably formed with a diameter / length ratio of greater than 1:10, preferably greater than 1: 5. The cylindrical rollers have a circumferential axis of rotation of its own cylinder surface and two the cylindrical roller final faces.

The outer ring has, in particular in the region of the raceway section, an inner raceway, the inner ring has, in particular in the region of the raceway section, an outer raceway in each case for the cylindrical rollers. During operation of the cylindrical roller bearing, the cylindrical rollers roll or roll over the inner raceway or outer raceway.

Furthermore, the outer ring has a Festbordabschnitt and a Bördelbordabschnitt, wherein the two sections lead the cylindrical rollers or an optional cage of the cylindrical rollers in the axial direction to the main axis of rotation. For this purpose, the Festbordabschnitt an annular Festbordanlauffläche and the Bördelbordabschnitt a Bördelbordanlaufbereich on. The inner ring and the outer ring are made of metal, in particular of steel.

In the context of the invention it is proposed that the outer raceway and / or the inner raceway is formed by extrusion in the final contour or are. During extrusion, the temperature is in the workpiece, in this case in the inner ring or in the outer ring, lower than the recrystallization temperature of the base material of the workpiece. In particular, during extrusion, an inner ring blank or an outer ring blank is deformed at ambient or room temperature, preferably at a temperature of <50 degrees. During forming, however, it is possible that higher temperatures occur due to the work of forming in the workpiece, but also the higher temperatures are below the recrystallization temperature of the base material. It is advantageous that surface stresses in the inner ring or in the outer ring in the region of the respective raceway are generated by the extrusion, leading to an increase in performance. In addition, it is advantageous that the production process of extrusion molding can be carried out very inexpensively, especially at high volumes. Overall, the inner ring and the outer ring and thus the cylindrical roller bearing are inexpensive to produce and have good functional properties. By means of the method according to the invention, the inner raceway or the outer raceway is shaped by means of extrusion molding and thereby enables final contour or final shape production (net shape-shaping), in particular of the inner raceway or of the outer raceway. It also eliminates additional steps, such as the cleaning of scaling, which can occur during hot working.

It is particularly preferred that the outer raceway and / or the inner raceway in a longitudinal section along a main axis of rotation of the cylindrical roller bearing has a convex curvature, in particular elevation. In particular, the convex curvature is mirror-symmetrical to a radial plane in the axial center of the respective raceway. Alternatively or additionally, the convex curvature can be described in the longitudinal section as a circle segment, wherein the center of the circle segment lies in the median plane. In particular, a maximum raceway for the inner race is centered and / or a raceway minimum (based on the radial distance to the main axis of rotation) centered on the outer race. Alternatively or additionally, the outer race and / or the inner race is crowned.

Such a convex curvature causes the cylindrical rollers only a small contact area with the unloaded cylindrical roller bearing Outer raceway or inner raceway have. The low contact surface reduces friction so that the cylindrical roller bearing can run with low friction. On the other hand, if the cylindrical rollers roll on the outer raceway or the inner raceway, the outer raceway or inner raceway is deformed due to the Hertzian pressure, so that the cylindrical rollers have a linear or oval-linear contact area with the respective raceway. In this condition, stress can be dissipated over a large contact area.

Comparing the convex curvature of the outer raceway and / or the inner raceway with a straight cylinder jacket surface, wherein the cylinder jacket surface is applied to the peripheral, in particular local extremes of the outer race or inner race, the maximum deviation is at least two microns, preferably at least five microns. This small deviation is sufficient to reduce the friction. In contrast, it is preferred that the maximum deviation be less than twenty microns, preferably less than ten microns. The limitation of the deviation causes the outer raceway or inner raceway can be deformed in such a way that the cylindrical rollers lie linearly against the raceways at the normal load of the cylindrical roller bearing.

In a preferred embodiment of the invention, the cylindrical rollers in a longitudinal section along its own axis of rotation also on a convex curvature on the cylindrical roller track. Thus, a convex curvature of the cylindrical rollers rolls on a convex curvature of the raceways of the cylindrical roller bearing.

Another possible measure for reducing the friction in the cylindrical roller bearing is that the Festbordabschnitt forms a torusballige Festbordanlauffläche for the cylindrical rollers. The torusballige Festbordanlauffläche is characterized in that it is annular, but how a donut or toms is realized convex curved. The shape can also be referred to as a lifebuoy, tire or bead-shaped surface with a hole. Looking at a longitudinal section through the outer ring, so The contact surface extends rectified to a radial plane, which is aligned perpendicular to the main axis of rotation of the outer ring, over a circular ring area. Within this annular region, the torusballige fixed Bordanlauffläche a convex curvature, in particular increase.

It is preferable that the torus-ball fixed-flange abutment surface is made by extrusion molding. It is particularly preferred that the cylindrical rollers also have a torusballige contact surface or end face for engagement with the torusballige Festbordanlauffläche the Festbordabschnitts. Due to this development, the contact area between the cylindrical roller and Festbordabschnitt is particularly low, so that the friction in the cylindrical roller bearing is further minimized.

By torusballige Festbordanlauffläche, possibly further by the torusballige configuration of the end faces of the cylindrical rollers, it is achieved that the contact area between the end face of the cylindrical rollers and the Festbordabschnitt is reduced.

It is also preferable that the flange board portion forms a circumferential contact line as the flange flange starting portion. For this purpose, it is provided that the flange section - also considered in the longitudinal section - has a free end portion or collar, which is aligned at right angles to a radial plane perpendicular to the main axis of rotation, so that the Bördelbordanlaufbereich is formed by a free end, in particular corner of the free leg.

In a possible development of the invention, the Festbordabschnitt on an axial outside a securing contour in the form of a securing groove, which is formed circumferentially to the main axis of rotation. The securing contour is introduced by means of extrusion into the Festbordabschnitt. In a possible development of the invention, the Festbordabschnitt on a circumferential separating edge, which forms a passage opening of the outer ring. Another object of the invention relates to a method for manufacturing a cylindrical roller bearing according to the invention. In the context of the method, the outer race of the inner ring is made of an inner blank and / or the inner race of the outer ring of an outer ring blank by extrusion in final contour in a Hauptumformschritt. In particular, in the main forming step, the shaping for the inner race and / or for the outer race is implemented by extrusion into final contour.

The method according to the invention can optionally be supplemented by one, some or all of the following steps:

In a first possible step, the outer ring blank is extruded from a metal blank. In particular, the outer ring blank is formed as a cup with a circumferential wall and a bottom.

In the subsequent main forming step, the extrusion of the outer ring blank into an outer ring intermediate takes place, wherein in the Hauptumformschritt the inner race is formed. It is envisaged that in the Hauptumformschritt the bottom or at least a bottom edge portion of the outer ring blank is maintained.

In a subsequent optional step, cutting, in particular punching, of the bottom of the outer ring intermediate takes place to form the inner ring.

Optionally, it can be provided that the segregated soil forms a precursor for the inner ring. The inner ring is made by means of a Hauptumformschrittes starting from a circular disk. The annular disk can be formed by the ground or made of another semi-finished product.

Both in the extrusion of the outer ring and the inner ring raceways are made, which are aligned as a cylinder jacket surfaces coaxial and / or concentric with the main axis of rotation of the cylindrical roller bearing. It has become pointed out that the raceways automatically assume the previously described convex curvature by the manufacturing. Thus, the active surfaces of a tool for forming the raceways can be formed as straight cylinder jacket surfaces and still produce raceways, which has a convex curvature in the manner described. In particular, raceways are created in this way, which are formed in principle as undercut contours with respect to an axial Entformungsrichtung.

The torusballige Festbordanlauffläche, however, by forming technology by means of a tool which carries a negative contour of torusballigen Festbordanlauffläche introduced into the outer ring. The securing groove can already be introduced during the production of the outer ring blank by metal forming; alternatively, the securing groove is introduced during the main forming step.

Further features, advantages and effects of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying drawings. Showing:

Figures 1 a, 1 b, 1 c an outer ring, an inner ring and a rolling element of a cylindrical roller bearing as an embodiment of the invention;

Figure 2 is an illustration of the inventive method for manufacturing the cylindrical roller bearing with the components according to Figures 1 a, 1 b, 1 c.

1 a shows in a schematic longitudinal section a first component of a cylindrical roller bearing 1 (see FIG. 2) in the form of an outer ring 2. FIG. 1 b shows, as a further component of the cylindrical roller bearing 1, an inner ring 3 in a schematic longitudinal section. In FIG. 1 c, a rolling element in the form of a cylindrical roller 4 is shown in highly schematic form as a further component of the cylindrical roller bearing 1. The three components are each shown in a schematic longitudinal section along a main axis of rotation H of the cylindrical roller bearing 1. The outer ring 2 according to FIG. 1a has an inner raceway section 5 which carries an inner raceway 6 on the radially inner surface. The inner race 6 is aligned coaxially and / or concentrically to the main axis of rotation H and is realized in the coarse form as a cylinder jacket surface.

At one axial end, a Festbordabschnitt 7 is integrally formed on the inner raceway portion 5, which projects at right angles from the inner raceway portion 5 in the longitudinal section shown. The Festbordabschnitt 7 provides a Festbordanlauffläche 8 for the cylindrical rollers 4 available.

On the opposite axial side, the outer ring 2 has a flanged portion 9, which is also angled approximately at right angles from the inner race portion 5. The Bördelbordabschnitt 9 carries a Bördelbordanlaufbereich 12. The outer ring 2 has for mounting a circumferential, outer cylinder jacket-shaped bearing surface.

The inner ring 3 is formed as a straight hollow cylinder, which is aligned coaxially and / or concentrically with the main axis of rotation H. At its radial outer side of the inner ring 3 carries an outer race 10. The outer race 10 is formed in approximately cylinder jacket-shaped. Furthermore, the inner ring 3 has a passage opening 1 1 for receiving a support structure, such as an axle or a shaft.

The cylindrical rollers 4 are arranged between the outer race 10 and the inner race 6 and run or roll on this. In the axial direction, the cylindrical rollers 4 are guided by the Festbordabschnitt 7 and the Bördelbordabschnitt 9 and the corresponding Festbordanlauffläche 8 and the Bördelbordanlaufbereich 12.

A closer look at the components reveals the following details regarding the shape: In the basic form cylinder jacket-shaped inner race 6 according to Figure 1 a is convexly curved inwardly in the longitudinal section shown. In the figure 1 a, the convex curvature 13 of the inner race 6 is shown overdrawn with a dashed line. Compared to an unbent inner race, the convex curvature 13 of the inner race 6 has a height h of about ten micrometers. The convex curvature 13 of the inner race 6 is arranged centrally to the inner race 6, so that the extremum of the convex curvature 13 of the inner race 6 is located in the middle of the inner race 6. The convex curvature 13 may also be referred to as a part-circular curvature.

At Festbordabschnitt 7, the Festbordanlauffläche 8 has a convex curvature 14 of Festbordanlauffläche 8, which is torusballig formed in the longitudinal section shown.

The flanged portion 9 has in the longitudinal section shown a free end leg 15, which is aligned approximately perpendicular to the inner raceway section 5. Compared to a radial plane R perpendicular to the main axis of rotation H, the end leg 15 is inclined inwardly toward the inner raceway section 5. In this way, as a contact surface for the cylindrical rollers 4 in the longitudinal section, only a punctiform area or, viewed in the entirety, a circumferentially linear area results as the flange starting area 12.

The outer race 10 of the inner ring 3 according to Figure 1 b also has a convex curvature 17 (shown with a dashed line), which occupies a height h of about ten micrometers compared to a straight track.

As shown clearly in FIG. 1 c with a dashed line, the raceway surface of the cylindrical roller 4 also has a convex curvature 18 of the raceway surface. Optionally in addition, the cylindrical roller 4 at the end faces 19 each torusballige, circumferential structures 16 (shown overlined with a dashed line) have. It should be emphasized that the convex curvatures 13, 14, 18 and / or the torus-shaped structure 16 are greatly exaggerated in the figures and are smaller than 20 microns in height h.

As a result of the described details, the friction in the cylindrical roller bearing 1 (see FIG. 2) formed from the outer ring 2, the inner ring 3 and a plurality of cylindrical rollers 4 can be significantly reduced. In detail, the following improvements result: By the cooperation between the inner race 6 with the convex curvature 13 and the raceway surface of the cylindrical roller 4, optionally with the convex curvature 18, the friction in the cylindrical roller bearing 1 is reduced. By the cooperation between the outer race 10 with the convex curvature 17 and the raceway surface of the cylindrical roller 4, optionally with the convex curvature 18, the friction in the cylindrical roller bearing 1 is further reduced. Due to the interaction between the convex curvature 14 of the Festbordanlauffläche 8 and the torusballigen structure 16 at the end faces 19 of the cylindrical rollers 4, the friction in the cylindrical roller bearing 1 is further reduced. Due to the interaction between the Bördelbordanlaufbereich 12 and the torusballigen structure 16 on the end faces 19 of the cylindrical rollers 4, the friction in the cylindrical roller bearing 1 is further reduced.

FIG. 2 schematically shows a method for producing the cylindrical roller bearing 1 as an exemplary embodiment of the invention.

Starting from a metal blank 20, an outer ring blank 21 is produced in a preforming phase according to step I. The outer ring blank 21 has a bottom 22 and a circumferential wall 23 and is shown in partial section. The forming can be formed for example as a deep drawing. It can be seen that in the preforming step, a circumferential securing contour 24 is already introduced in the region of the bottom 22.

In a subsequent step II, the outer ring blank 21 is transferred into an outer ring intermediate product 25, which is shown in longitudinal section. Of the Step II is also referred to as the main forming step. The bottom 22 is separated along a separating edge 27, in particular punched out.

The floor punched out according to step II bottom 22 or another circular disk 26, shown here in section, forms a precursor for the inner ring 3. This is formed according to a step III from the punched-out bottom 22 or the circular disk 26 by folding and widening, as shown in the lower line of Figure 2 is shown. Under step III, a longitudinal section through the outer ring 2 after formation of the Bördelbordabschnitt 9 according to step IV is already shown in the upper row, but as this is only present in the fully assembled cylindrical roller bearing 1.

In a final step IV, the outer ring 2 (as shown in step II) and the inner ring 3 (as shown in step III) are mounted together with the cylindrical rollers 4 and the Bördelbordabschnitt 9 bent on the outer ring 2. As a result, an arrangement of the cylindrical rollers 4 in the outer ring 2 is fixed. The finished cylindrical roller bearing 1 is shown in the sectional view.

The convex curvature 13 of the inner race 6 and the convex curvature 17 of the outer race 10 result from extrusion in the method according to the invention. In particular, the active surfaces of the tool for forming the inner race 6 and the outer race 10 are formed as straight cylinder jacket surfaces. By contrast, the convex curvature 14 of the fixed flange contact surface 8 is embossed by a tool having a complementary active surface (see FIG. 1 a).

LIST OF REFERENCE NUMBERS

1 cylindrical roller bearing

2 outer ring

3 inner ring

4 cylindrical roller

5 inner race section

6 inner race

7 stall section

8 fixed ramp surface

9 Bördelbordabschnitt

10 outer raceway

1 1 passage opening

12 Bördelbordanlaufbereich

13 convex curvature of the inner race

14 convex curvature of the Festbordanlauffläche

15 thighs

16 torus-shaped structure

17 convex curvature of the outer raceway

18 convex curvature of the raceway surface of the cylindrical roller

19 front side

20 metal blanks

21 outer ring blank

22 floor

23 surrounding wall

24 securing contour

25 outer ring intermediate

26 circular disk

27 separating edge

H main axis of rotation

R radial plane

h height (maximum deviation)

Claims

claims

1 . Cylindrical roller bearing (1) with an inner ring (3), with an outer ring (2) and with a plurality of cylindrical rollers (4), wherein the cylindrical rollers (4) between the inner ring (3) and the outer ring (2) are arranged, wherein the Outer ring (2) has an inner race (6) for the cylindrical rollers (4), a Festbordabschnitt (7) and a Bördelbordabschnitt (9), and wherein the inner ring (3) has an outer raceway (10) for the cylindrical rollers (4), characterized in that the inner race (6) and / or the outer race (10) is or are formed by extrusion in final contour.

2. Cylindrical roller bearing (1) according to claim 1, characterized in that the inner raceway (6) and / or the outer raceway (10) in a longitudinal section along a main axis of rotation (H) of the cylindrical roller bearing (1) has a convex curvature (13,17).

3. Cylindrical roller bearing (1) according to claim 2, characterized in that the convex curvature (13,17) with respect to a straight cylindrical surface at least a maximum deviation (h) of 2 μιτι, preferably of at least 5 μιτι, and / or less than 20 μιτι , preferably of less than 10 μιτι has.

4. Cylindrical roller bearing (1) according to one of the preceding claims, characterized in that the cylindrical rollers (4) in a longitudinal section along a main axis of rotation (H) of the cylindrical roller bearing (1) have a convex curvature (18).

5. cylindrical roller bearing (1) according to any one of the preceding claims, characterized in that the Festbordabschnitt (7) a torusballige Festbordanlauffläche (8) and / or a convex curvature (14) of Festbordanlauffläche (8) for the cylindrical rollers (4).

6. cylindrical roller bearing (1) according to any one of the preceding claims, characterized in that the Bördelbordabschnitt (9) forms a circumferential contact line as Bördelbordanlaufbereich (12).

7. Cylindrical roller bearing (1) according to one of the preceding claims, characterized in that the Festbordabschnitt (7) has a securing contour (24), wherein the securing contour (24) by extrusion in forming the Festbordabschnitt (7) is introduced.

8. cylindrical roller bearing (1) according to one of the preceding claims, characterized in that the Festbordabschnitt (7) has a circumferential separating edge (27).

9. A method for manufacturing a cylindrical roller bearing (1) according to any one of the preceding claims, characterized in that the outer race (10) of the inner ring (3) of an inner ring blank and / or the inner raceway (6) of the outer ring (2) from an outer ring blank ( 21) is made by extrusion in final contour.

A method according to claim 9, characterized in that the method comprises one, some or all of the following steps:

Extruding an outer ring blank (21) from a metal blank (20), wherein the outer ring blank (21) is formed as a cup;

Extruding the outer ring blank (21) into an outer ring intermediate (25), wherein the inner race (6) is formed into final contour; Cutting out a bottom (22) from the outer intermediate product (25) to form the inner ring (2).