ROLLER BEARING

Description

Technical field

[0001] The invention relates to a roller bearing, in particular a double-row spherical roller bearing, comprising an inner ring and an outer ring as well as a plurality of rolling elements arranged in two rows on corresponding raceways on the inner ring and the outer ring, wherein the outer ring is radially divided to form at least two ring sections.

[0002] Such a double-row spherical roller bearing is known, for example, from DE 10 2011 086 925 A1. The spherical roller bearing described therein is characterized by the fact that the outer ring and / or the inner ring consist of two ring sections or ring halves that connect circumferentially, meaning that the respective ring is radially divided, with each section having a radial division plane. Such divided rings are primarily used in large bearings, as this simplifies bearing assembly. Because the inner and / or outer ring is multi-part, its components can be mounted separately. Such bearings are used, for example, in complex drive trains and offer the advantage that, in the event of bearing failure, the bearing can be replaced without partial or complete disassembly of the drive train.

[0003] The ring is typically divided by breaking it at defined points or in a defined plane, thus preventing material loss during separation, which would occur, for example, if it were sawn apart. Breaking creates a defined fracture line, meaning the ring material breaks along the grain boundaries, with the fracture line running in the desired plane. During assembly, the corresponding ring sections are then reassembled. In the case of a split inner ring, for example, it is fixed to the shaft using laterally circumferential clamping rings, while a split outer ring is inserted into the corresponding housing component.

[0004] The invention is therefore based on the problem of providing an improved spherical roller bearing in comparison.

[0005] When such split roller bearings or spherical roller bearings are used, for example, in wind turbines, the rolling elements, which roll on the raceways of the ring sections and over the transitions between them, subject the joints between the ring sections to high loads. It has been found that, due to ring fractures whose fracture lines run perpendicular to the raceway, the microstructure of the ring material can create tiny peaks or irregularities at the edges on the raceway side of the ring sections, which impair the raceway's smoothness. If the rolling elements then roll over these slightly disturbed raceway areas during operation, raceway damage can occur over time, and the rolling elements themselves can also be damaged.To counteract this phenomenon, it is known from DE10 2017 110 742 A1 to provide the area where the raceway sections of two ring sections abut each other with a relief grinding, i.e., to slightly deepen the raceway locally by creating a groove- or pit-like depression with a continuous cross-section in the area of ​​contact, which is only a few tenths of a millimeter to a few millimeters deep and wide. Nevertheless, the connecting elements that form the outer ring of the roller bearing between the respective ring sections are subject to high stress. In the operation of split roller bearings, it has been observed that the connecting elements between the ring sections on the outer ring loosen or even break off, thereby leading to bearing damage.

[0006] WO 2013 / 047617 A1 and US 2012 / 087611 A1 each disclose a roller bearing with rings consisting of several segments and featuring a relief. However, the ring segments do not have butt joints because the ring segments are spaced apart from each other.

[0007] Therefore, the invention is based on the objective of providing a split roller bearing, in particular a spherical roller bearing, with improved service life with regard to the connecting means between the ring sections. Description of the invention

[0008] This problem is solved with the features specified in claim 1. Advantageous embodiments and further developments of the invention can be found in claims 2 to 9. If at least each relief on the outer ring has an arc-shaped profile extending transversely to the impact area, wherein the greatest radial depth T of the relief lies exactly in the impact area, and if each relief extends in the circumferential direction of the raceway of the outer ring over a length that corresponds at most to the circumferential distance X between the contact point of a first rolling element and the contact point of a rolling element next but one with respect to this first rolling element with the raceway, and which is greater than half the diameter of a rolling element at its largest diameter point, then a design or further development of the invention is achieved.Threading grooves for rolling elements are created on both sides of the impact zone between two ring sections. These grooves function as disengagement grooves, gradually reducing the pressure of the rolling elements in the raceways until they reach the immediate impact zone. Conversely, as threading grooves, they gradually increase the pressure of the rolling elements in the raceways after they have rolled over the immediate impact zone. According to the applicant, this gradual transition ensures that the connecting elements are subjected to little or no stress in the circumferential direction when rolling over the impact zones, and that such forces only result in elastic deformation of the ring sections. It is advantageous if the depth T of the relief groove lies between 0.05 and 0.0001 times the diameter D of the rolling element at its largest diameter point, as such depths T eliminate the need for measures to compensate for the weakening of the outer ring.

[0009] Assembly and disassembly are simplified if the inner ring and / or the outer ring is radially divided into more than two ring sections, with a relief groove provided at each joint. It is preferred if the outer ring is divided into two mutually orthogonal planes. The ring then consists of four ring sections, each circumferentially rotating at 90°, which complement each other circumferentially. In this case, the divided ring has four joints, each with corresponding relief grooves.

[0010] A further advantageous embodiment of the invention provides that the outer ring is axially divided into two partial rings, forming axially adjacent ring sections. According to this embodiment, the outer ring, unless radially divided, is divided into two separate partial rings that are axially adjacent to one another. Due to the axial division, there are then two ring sections, each forming a single partial ring. However, if the outer ring is divided into circumferentially complementary ring sections in one or more radial planes, and is additionally divided in an axial plane, then there is a plurality of corresponding ring sections, which, on the one hand, complement each other circumferentially to form a partial ring, and on the other hand, the two multi-part partial rings then complement each other to form the complete outer ring.If, for example, the outer ring is divided radially along a plane into two ring sections and additionally divided axially, there are a total of four ring sections, with each pair of ring sections forming a partial ring. If the outer ring is divided radially in two orthogonal planes, and an additional axial division is provided, there are a total of eight ring sections, with each pair of ring sections forming a partial ring. This axial division also simplifies the assembly of the bearing, especially in the case of an asymmetric bearing.

[0011] It is conceivable that the partial rings are in contact with each other in the assembled position, with at least one radial bore provided in the area of ​​the axial separation point for supplying lubricant into the bearing interior. Here, the partial rings abut directly against each other. To lubricate the bearing, it is therefore advantageous to provide one or more radial bores that penetrate the assembled outer ring in the area of ​​the separation plane or separation point. Lubricant can be supplied into the rolling bearing interior via these bores to ensure continuous lubrication.

[0012] Alternatively, the two partial rings can be axially spaced apart, forming an annular gap. This axial spacing can be achieved, for example, by slightly grinding the axial end faces, thus removing a small amount of material. When the partial rings are mounted and slid onto the rows of rolling elements, the grinding or material removal prevents them from being pushed completely against each other without creating an unacceptably high bearing preload. This means that a circumferential gap exists, allowing lubricant to be supplied. Furthermore, it is possible to adjust the preload or bearing clearance for one or both rows of rolling elements, depending on how each partial ring is axially positioned relative to its respective row.The design is such that the two partial rings do not touch axially even when the bearing clearance is zero, i.e., when there is no operating clearance or a low preload is set.

[0013] In addition to the outer ring, the inner ring can also be divided into one or more planes. This inner ring also features a corresponding relief in the respective joint area.

[0014] If the inner ring is also radially split, it is advisable to clamp it to the shaft using appropriate clamping rings. These clamping rings, which also consist of two ring halves, are placed around the split inner ring at each end and screwed together, thus clamping the inner ring firmly onto the shaft.

[0015] The rolling elements of each row are preferably received or guided within a rolling element cage. This rolling element cage, which is preferably made of metal and is, for example, a sheet metal component (although a plastic version is not excluded), secures or guides the corresponding rolling elements, in this case, spherical rollers. It may be advantageous if each rolling element cage is radially divided into at least two cage sections, which in turn facilitates assembly.

[0016] The spherical roller bearing itself can be an asymmetrical bearing, meaning that the contact angle of the first row of rolling elements and the contact angle of the second row of rolling elements are different. Preferably, identical rolling elements are used in both rows of rolling elements, unlike in the prior art, particularly according to DE 10 2011 086 925 A1, where different rolling elements are provided in each row. However, it can also be a symmetrical bearing in which the contact angles are the same. Brief description of the characters

[0017] They show: Figure 1 is a perspective partial view of a two-row spherical roller bearing according to the invention, Figure 2 is a sectional view of a part of the spherical roller bearing made of Figure 1 along line II - II, Figure 2: embodiment of a free-cutting according to the invention; Figure 3: a sectional view along line III - III in Figure 1, and Figure 4 shows a second embodiment of a spherical roller bearing according to the invention in a sectional view. Figure 3 . Ways to implement the invention

[0018] The invention will now be explained in more detail using the figures.

[0019] Figure 1 Figure 1 shows an asymmetric double-row spherical roller bearing 1 according to the invention, comprising an outer ring 2, an inner ring 3 and, see for example, the figure 1. Figure 2 , a multitude of rolling elements 4 rolling between outer ring 2 and inner ring 3, here in the form of barrel-shaped rollers, as in Figure 3 The rolling elements 4 of both rows are identical, see e.g. the Fig. 3 and 4 Such a bearing can be used, for example, in a wind turbine. In such an application, the bearing typically has a width of several hundred millimeters.

[0020] In the example shown, the outer ring consists of two sub-rings 5a, 5b, as shown in particular by the Figure 3 and 4 show that it is divided along an axial plane 6.

[0021] Furthermore, each subring 5a, 5b consists of two ring sections 7a, 7b and 8a, 8b respectively, which are adjacent to each other, see Figure 1 , circumferentially to the respective subrings 5a, 5b. The subrings are thus aligned along a radial plane 9, see Figure 1 , divided. This means that the outer ring 2 is divided along an axial plane 6 and a radial plane 9 into a total of four ring sections 7a, 7b and 8a, 8b, which complement each other to form two circumferential partial rings 5a, 5b.

[0022] In the example shown, the inner ring 3 is also divided into two ring sections 10a, 10b along a radial plane 11. These ring sections 10a, 10b also complement each other circumferentially to form the inner ring 3. How Figure 3However, as shown, the inner ring is not axially divided; it is only divided along the radial plane 11.

[0023] To fix the inner ring 3 to a shaft (not shown) or the like, two clamping rings 12, 13 are provided, each consisting of two clamping ring sections 12a, 12b and 13a, 13b respectively, and which are firmly connected to one another by corresponding screw connections 14 in order to clamp the split inner ring 3, on whose axial end sections they are arranged, firmly onto the shaft. For this purpose, the inner ring 3 can have a corresponding annular groove-like engagement geometry 15, 16 at the respective ends, into which the clamping rings 12, 13 engage in a form-fitting manner.

[0024] As described, the rings can be fractured along the respective planes 6 and especially 9. Due to the microstructure of the material, usually steel, this results in a fracture zone that is undefined from the surface after the fracture occurs along the grain boundaries. Consequently, when the ring sections are joined circumferentially, local peaks or inhomogeneities arise, particularly in the edge region of ring sections 7a, 7b, 8a, 8b and 10a, 10b respectively, where the respective raceways 17, 18 are located on the outer ring 2 and the inner ring 3. These are eliminated by grinding a relief 19, 20 in the joint area of ​​each of the two ring sections, see [reference]. Figure 2a , is formed. Such a relief grind forms a depression 21, 22 with a depth T of a few tenths of a millimeter to a few millimeters, as in Figure 2aThe basic design is not shown to scale for the recess 22. This relief 19, 20 or the recess 21, 22 extends over the entire length of the axial joint. An embodiment according to the invention of a recess 21 or a relief 19 on an outer ring 2 or between the ring sections 8a, 8b forming the outer ring 2 is Fig. 2b The relief 19 shown there is formed as an arc-shaped, radially outwardly directed recess 21 in the raceway 17 of the outer ring 2, the greatest radial depth T of the recess 21 being located where the two ring sections 8a, 8b abut each other. In the embodiment according to Fig. 2b The depth T is approximately 0.025 times the diameter D of the rolling elements 4. This recess 21 has in Fig. 2bIn the illustrated embodiment, the width—that is, the circumferential extent—corresponds to the diameter D of the rolling elements 4 rolling between the bearing rings 2, 3. This relatively large width of the recess 21 between the two ring sections 8a, 8b of the outer ring 2 serves a dual purpose: The respective reliefs 19 (20) and their circumferential extent of the bearing 1 relieve the corresponding impact zones of load. This ensures continuous operation despite the inevitable microstructural inhomogeneity in the impact zone due to the fracture, as the respective raceways in the impact zones are not subjected to load and thus cannot be damaged. Furthermore, the large circumferential extent of the recesses 21 (22) of the bearing 1 also ensures that the fitted screw 29, which according to Fig. 2bThe two ring sections 8a, 8b forming the outer ring 2 are not subjected to load by rotating rolling elements 4 during the operation of the bearing 1, even if the bearing rings 2 formed by ring sections 8a, 8b deviate somewhat from the shape of an ideal circular ring. Rather, the large circumferential dimensions of the arcuate recesses 21( 22), together with the tangential transition area of ​​the raceway and the relief 19 (20), form a kind of entry and exit zone for rolling elements 4 that have passed the immediate interface between two ring sections 8a, 8b. In order for the respective recesses 21, 22 to actually function as entry and exit zones that relieve the screws 29, the circumferential width of the recesses 21, 22 should be equal to or greater than half the diameter D of the rolling elements 4 used.Advantageous effects of recesses 21, 22 are no longer perceptible when their circumferential extent is greater than the circumferential distance X between the contact point B1 of a first rolling element 4 and the contact point B2 of a rolling element 4 next but one with the raceway 17.

[0025] Figure 3 shows a sectional view along line III - III according to Figure 1 The rolling elements 4 are evidently designed as barrel-shaped rollers that roll on the corresponding raceways 17a, 18a and 17b, 18b of the inner ring 3 and the partial rings 5a, 5b. They are each received and guided in a cage 23, 24, which may optionally also be radially divided into at least two cage halves. In the embodiment according to Figure 3The two partial rings 5a, 5b lie axially against each other, i.e., they touch each other in the area of ​​the axial plane 6 separating them. In order to supply lubricant, one or more radial bores 25 are provided.

[0026] Due to the axial contact of the partial rings 5a, 5b, the design according to Figure 3 It is not possible to adjust the bearing clearance within the respective rows of rolling elements, therefore no clearance compensation is provided.

[0027] Figure 4 In contrast, shows an embodiment of a double-row spherical roller bearing 1, which in this respect corresponds to the embodiment according to the Figures 1 to 3 corresponds, in particular with regard to the formation of the corresponding ring sections and the corresponding reliefs 19, 20 at the joint areas. In the design according to Figure 4However, the partial rings 5a, 5b are not positioned axially abutting each other; rather, a circumferential annular gap 26 is formed, through which the lubricant can be supplied. This annular gap 26 can be formed by grinding the end faces 27a, 27b of the partial rings 5a, 5b, thus removing a small amount of material.

[0028] Secondly, since they do not touch each other, the clearance or bearing clearance in the respective rows of rolling elements can be adjusted, as exemplified in Figure 4Figure 28 shows a small clearance 28 in the area of ​​the right-hand bearing row. This clearance, or bearing air, can be adjusted by appropriate axial positioning of the respective sub-ring 5a, 5b. However, it can also be completely eliminated if desired, meaning that there is no clearance, and a small preload can also be set if necessary. Regardless, even with a small preload, the two sub-rings 5a, 5b do not axially contact each other, as this would ultimately limit the adjustment possibilities.

[0029] As the Figure 3 and 4Finally, it can be shown that the spherical roller bearing 1 is an asymmetrical spherical roller bearing, since the contact angles exhibited by the two rows of rolling elements differ slightly. The contact angle of the row of rolling elements shown on the right is somewhat larger than the contact angle of the row of rolling elements shown on the left. The contact angles are represented by α and β for illustrative purposes. However, the rolling elements 4 of both rows of rolling elements are identical.

[0030] Although in the described example the outer ring 2 and the inner ring 3 are divided circumferentially into two ring sections 7a, 7b and 8a, 8b respectively with respect to the outer ring 2 and 10a, 10b with respect to the inner ring 3, it is of course conceivable to divide one or both rings radially in two preferably orthogonal planes, so that each ring or partial ring would then consist of four complementary ring sections. Reference symbol list

[0031] 1. Spherical roller bearing 2. Outer ring 3. Inner ring 4. Rolling element 5a. Partial ring 5b. Partial ring 6. Axial plane 7a. Ring section 7b. Ring section 8a. Ring section 8b. Ring section 9. Radial plane 10a. Ring section 10b. Ring section 11. Radial plane 12a. Clamping ring section 12b. Clamping ring section 13a. Clamping ring section 13b. Clamping ring section 14. Screw connection 15. Engagement geometry 16. Engagement geometry 17. Raceway 17a. Raceway 17b. Raceway 18. Raceway 18a. Raceway 18b. Raceway 19. Relief 20. Relief 21. Recess 22 Recess 23 Cage 24 Cage 25 Radial bore 26 Annular gap 27a End face 27b End face 28 Clearance 29 Dowel screw 30 Shank, unthreaded

Claims

1. A roller bearing, in particular a spherical roller bearing, comprising an inner ring and an outer ring as well as a plurality of rolling elements arranged in two rows on corresponding raceways (17a, 17b, 18a, 18b) on the inner ring (3) and on the outer ring (2), wherein the inner ring (2) and / or the outer ring (3) is radially divided, forming at least two ring sections, wherein at least one fitted screw (29) is provided in the abutment area of each pair of ring sections (7a, 7b, 8a, 8b, 10a, 10b), which fitted screw connects the two ring sections (7a, 7b; 8a, 8b; 10a, 10b), wherein the abutment area between the respective ring sections (7a, 7b; 8a, 8b; 10a, 10b) cuts each threadless shaft (30) of the respective fitted screw (29), and wherein the raceway in the abutment area of two ring sections (7a, 7b, 8a, 8b, 10a, 10b) has a relief (19, 20) locally deepening the raceway (17a, 17b, 18a, 18b), characterised in that at least each relief (19) on the outer ring (3) has an arc-shaped profile extending transversely to the abutment area, wherein the greatest radial depth (T) of the relief lies exactly in the abutment area, and each relief (19) extends in the circumferential direction of the raceway (17) of the outer ring (3) over a length that corresponds at most to the circumferential distance (X) between the contact point (B1) of a first rolling element (4) and the contact point (B2) of a rolling element (4) next but one with respect to this first rolling element (4) with the raceway (17) and is greater than half the diameter (D) of a rolling element (4) at its largest diameter point.

2. The roller bearing according to claim 1, characterised in that the depth (T) of the relief is between 0.05 and 0.0001 * the diameter (D) of the rolling element (4) at its largest diameter point.

3. The roller bearing according to claim 1 or 2, characterised in that the inner ring (3) and / or the outer ring (3) is radially divided into more than two ring sections (8a, 8b, 10a, 10b), wherein a relief (19, 20) is provided in each abutment area.

4. The roller bearing according to any one of the preceding claims, characterised in that the inner ring (3) and / or the outer ring (2) are each divided into two planes (9) extending orthogonally to each other.

5. The roller bearing according to any one of the preceding claims, characterised in that the outer ring (3) is axially divided into two partial rings (5a, 5b), forming ring sections (7a, 7b; 8a, 8b) that are axially adjacent to one another.

6. The roller bearing according to claim 5, characterised in that the partial rings (5a, 5b) abut each other, wherein at least one radial bore (25) is provided for supplying a lubricant into the bearing interior in the region of the axial separation point.

7. The roller bearing according to claim 5, characterised in that the two partial rings (5a, 5b) are axially separated from each other, forming a gap (26).

8. The roller bearing according to any one of the preceding claims, characterised in that the pressure angle (α) of the first row of rolling elements and the pressure angle (β) of the second row of rolling elements are different, wherein the rolling elements of both rows of rolling elements are identical.

9. The roller bearing according to any one of the preceding claims, characterised in that the rolling elements (4) of each row are received in a rolling element cage (23, 24).