ROLLER BEARING AND SPACER THEREFORE

Description

[0001] The present invention relates to a rolling bearing with two concentric races, between which a plurality of rolling elements are provided in a bearing gap, which roll on at least two raceways, wherein intermediate pieces are provided between the rolling elements, which keep the rolling elements spaced apart from one another.

[0002] To keep the rolling elements of a rolling bearing spaced apart from each other and evenly distributed in the running direction, spacers or rolling element cages are typically used. For example, if rolling elements are used in the form of balls, the spacers are usually cylindrical pieces whose end faces are approximately hemispherical indentations or troughs, so that each spacer with the end-face troughs can nestle against the leading and trailing balls, see, for example, WO 2019 / 048251 A1.

[0003] The cylindrical ring section of the intermediate piece is typically connected to a central section by connecting struts, as shown, for example, in documents DE 10 2015 223 511 A1, FR 23 43 922 A1, and JP 2002 173 951 A, or in the Liebherr "Slewing Bearing Product Catalog." These connecting struts, together with the central section and the ring section, form the end-face troughs. Alternatively, a closed-walled trough can also be provided, as schematically shown in WO 2019 / 048251 A1.

[0004] Depending on the shape of the rolling element, the aforementioned spacers can be contoured differently or adapted to the shape of the rolling element, whereby, for example, in the case of cylindrical rollers, end-face troughs adapted to the cylindrical shape can be formed.

[0005] Such conventional spacers take up a relatively large amount of space in the bearing or bearing gap, leaving relatively little room for the lubricant to be introduced into the bearing. For example, in slewing bearings with lifetime lubrication, as shown in WO 2019 / 201662 A1, the lubricant is usually stored in the bearing gap. Not only does the space required by the spacer itself reduce the amount of lubricant that can be stored, but there is also the problem that old grease accumulates in the recesses of the spacer, compromising the supply of fresh lubricant to the rolling elements.

[0006] More space for the lubricant is available when using rolling element cages. Such rolling element cages can, for example, form a ring in a pivot bearing, in which recesses for the rolling elements are provided at equal spacing, so that each rolling element is encompassed by the rolling element cage and adjacent rolling elements are spaced apart by a corresponding web.

[0007] A disadvantage of such rolling element cages, however, is that the raceways are shortened at their edges when viewed in cross-section. This is because the rolling element cages require space at the interface between the two raceways. The required gap between two adjacent raceways requires a certain thickness to accommodate the lateral edges of the rolling element cage. The rolling element cage typically runs in a plane perpendicular to the main support direction of the rolling element bearing—for example, in an axial bearing, in a plane perpendicular to the direction of rotation, and in a radial bearing, along a cylindrical surface between the outer and inner rings.

[0008] Particularly in slewing bearings, but also in other highly loaded rolling bearings, a shortening of the cross-sectional extent of the raceways at their edges can lead to what is known as edge wear. This means that very high point loads occur between the rolling element and the raceway directly at the shortened edges. For example, in ball bearings, the raceways of highly loaded bearings, viewed in cross-section, conform relatively closely to the respective hemispherical shape. However, if the edges of these raceways are shortened for the aforementioned reason to accommodate the rolling element cages, the load-bearing capacity decreases and edge wear can occur, which can lead to increased wear or even damage.

[0009] In addition, with rolling element cages the number of usable rolling elements is also reduced, which in turn has a negative impact on the load-bearing capacity of the bearing.

[0010] The present invention is therefore based on the object of creating an improved rolling bearing of the aforementioned type, in particular a slewing bearing, that avoids the disadvantages of the prior art and advantageously develops them further. In particular, the rolling elements are to be kept at a distance in a low-friction and space-saving manner, and comprehensive, permanent lubrication of the bearing is to be enabled.

[0011] According to the invention, the stated object is achieved by a rolling bearing according to claim 1. Preferred embodiments of the invention are the subject of the dependent claims.

[0012] It is therefore proposed to space the rolling elements using spacers with a reduced-volume, thus creating space. The reduced volume of the spacer allows a greater amount of lubricant to be introduced into the bearing gap and stored there, while simultaneously preventing the deposition of old lubricant. This allows for better oil delivery of the lubricant into the loaded contact area near the rolling contact, and thus an overall better supply of fresh lubricant to the rolling elements.

[0013] According to one aspect of the present invention, the ring or outer frame section of the intermediate piece, which is connected to the central section via struts, is designed as a rod or skeleton structure with window- and / or door-arch-like recesses. By using a lattice-like outer frame instead of a conventional solid material ring, more lubricant can be stored, especially in the area near the raceways, and the supply of lubricant to the contact points between the rolling elements and raceways can be improved. These recesses or openings can act as lubricant pockets in which lubricant can be kept in the immediate vicinity of the rolling elements.

[0014] In an advantageous development of the invention, the aforementioned recesses in the rod or skeleton structure of the outer frame or ring section can each be open toward an axial side of the intermediate piece and enclosed by a U-shaped frame section, in particular in the form of a U-shaped web frame. In particular, the outer frame or ring of the intermediate piece can have a castle-like configuration, in which preferably web-shaped material sections alternate with recesses open at the end when the intermediate piece is viewed in the circumferential direction. This allows lubricant to be stored in the region of the recesses and released to the contact points between the rolling element and the raceway.

[0015] Advantageously, the ring section or frame part of the intermediate piece can have recesses open towards opposite axial sides, so that open recesses are provided towards each axial or end face.

[0016] The recesses open towards opposite sides can in principle be arranged overlapping one another when viewed in the running direction, for example formed or enclosed by H-shaped borders.

[0017] Advantageously, the recesses open towards opposite axial sides can also be arranged offset from one another, so that, viewed in the circumferential direction, recesses open towards different axial sides can be provided in the ring section alternately.

[0018] In particular, the recesses can be open alternately to opposite axial sides and be enclosed by edge webs that form a meandering skeleton structure in the circumferential direction. Such a meandering skeleton structure can achieve structural elasticity that, on the one hand, prevents the respective intermediate piece from tilting, while, on the other hand, avoiding increased frictional resistance.

[0019] To ensure as much lubricant as possible is introduced into the bearing gap, the ratio of material sections to recesses in the outer frame or ring section can be relatively small. Advantageously, the material sections of the ring section or frame part can form less than 50%, less than 30%, or even less than 20% of the annular envelope surface that circumferentially encloses the ring section of the intermediate piece, including its recesses. In other words, the "bones" of the ring skeleton can make up or occupy less than half or even less than 1 / 4 of the annular envelope surface.

[0020] In the area of ​​the ring section, more material may be removed than is left for the skeletal structure. The ring or outer frame section may have more openings than skeletal bones.

[0021] Advantageously, said skeletal structure may consist of substantially uniformly thin and / or elongated rod or bone sections which are connected to one another and together form said skeletal structure.

[0022] In a further development of the invention, the ring section or the outer frame part of the intermediate piece can protrude beyond the central section on both axial sides, wherein said central section can be connected via the connecting struts to a central section of the ring section or outer frame part, viewed in the axial direction. The connecting struts can be hinged to the ring section approximately centrally, particularly viewed in the axial direction.

[0023] If the ring section is designed as a skeleton structure, for example a meandering skeleton structure, in the manner described, the connecting struts can be attached to rod or bone sections of the skeleton structure which extend at least approximately in the axial direction and / or form a side leg of the U-shaped borders of a respective recess.

[0024] According to the invention, the intermediate piece is contoured in such a way that at least substantially only the central section transmits the force and / or substantially only the central section forms the force-transmitting abutment surface of the intermediate piece in order to keep the rolling elements at a distance in the direction of rotation.

[0025] In particular, the connecting struts connecting said central portion to the ring or outer frame portion of the intermediate piece may be designed such that they remain without contact with the rolling elements and / or do not transmit any forces in the running direction between the rolling elements.

[0026] For example, the connecting struts mentioned can be designed as rod-shaped spokes, which are attached to the central section on one side and to the outer frame or ring section on the other. The spoke-shaped design of the connecting struts also creates plenty of space in the annular area around the central section to accommodate lubricant. At the same time, the buildup of old, used lubricant can be counteracted.

[0027] The central section of the intermediate piece, which forms the force-transmitting contact point of the intermediate piece in the running direction, can be relatively small compared to the overall diameter or the overall thickness or width of the intermediate piece. For example, the central section can have a thickness or transverse extent (transverse to the running direction) of less than 50%, less than 30%, or less than 20% of the maximum diameter or maximum transverse extent of the intermediate piece.

[0028] The invention is explained in more detail below using a preferred embodiment and the accompanying drawings. In the drawings: Fig. 1: a partial, cut-away, perspective view of a rolling bearing according to an embodiment of the invention, in which the spherically shaped rolling elements are kept at a distance by spacers, Fig. 2: a perspective view of an intermediate piece of the rolling bearing from Fig. 1 according to an advantageous embodiment of the invention, Fig. 3: a side view of the intermediate piece from Fig. 1 , which shows the meandering skeleton shape of the outer ring section of the intermediate piece, Fig. 4: a frontal plan view of the intermediate piece from the previous figures, which shows the spoke-shaped connecting struts between the central section and the outer ring section, and Fig. 5: a sectional view of the intermediate piece along the line AA in Fig. 4 .

[0029] How Figure 1shows, the rolling bearing 1 can be designed as a pivot bearing, for example in the form of a center-free large rolling bearing, and can have two bearing rings 2, 3, for example in the form of an inner and an outer ring, wherein the bearing can be designed as an axial bearing or as a radial bearing or even as a mixed form that supports both axial forces and radial forces.

[0030] When designed as a linear bearing, instead of the two in Figure 1 shown bearing rings 2, 3, corresponding bearing track bodies can also be provided, which then extend linearly and can, for example, be designed like rails.

[0031] How Figure 2shows, the rolling bearing 1 can comprise two rows of bearings, which can be arranged, for example, on opposite sides of a ring nose, with which one bearing ring 2 can engage in a groove in the other bearing ring 3. However, the rolling bearing 1 can also comprise only one row of rolling bearings or more than two rows of rolling bearings, wherein axial and radial rows can be combined with one another or provided individually.

[0032] The bearing rings 2, 3 can have a raceway 4 or 5 for each row of rolling elements, which face each other and are supported against each other by a row of rolling elements 6 which roll on the said raceways 4 and 5.

[0033] How Figure 1shows, the rolling elements 6 can, for example, be spherical. Accordingly, the raceways 4 and 5 can each be curved in a shell-like or half-shell-like manner in order to conform to the spherical rolling elements 6. Alternatively, partially shell-shaped raceways can also be provided in which the rolling elements 6 run if the bearing is designed as a multi-point bearing, for example a four-point bearing. However, it is understood that other rolling elements, for example cylindrical or barrel-shaped rolling elements, can also be provided, and the raceways 4 and 5 can then be adapted to the rolling elements 6 in a correspondingly different manner.

[0034] Spacers 7 are arranged between the rolling elements 6, which keep the rolling elements 6 at a distance and ensure a uniform distribution of the rolling elements 6 along the raceways 4, 5. An intermediate piece 7 can be provided between each two adjacent rolling elements 6.

[0035] The said intermediate pieces 7 can be designed separately or unconnected from one another.

[0036] How Figure 2 As shown, the spacers 7 each have a skeletal structure that can include openings both in the running direction and transversely to the running direction. Due to the absence of closed cross-sections in the axial direction and / or in the radial direction, lubricant can be exchanged or replenished past the spacers 7, and deposits of old, used lubricant in the area of ​​the spacers can be avoided.

[0037] As the Figures 2 to 5 show, the intermediate piece 7 comprises a central section 8 which is connected by connecting struts 9 to an outer frame part 10 which may be annular and surround the central section 8.

[0038] The central section 8 forms the force-transmitting abutment surfaces in the running direction of the rolling bearing row, which keep the adjacent rolling elements 6 at a distance or against which the rolling elements 6 can abut.

[0039] The outer frame part 10, which is significantly larger in diameter and transverse extent, holds the central section 8 in position and prevents said central section 8 from tilting. For this purpose, said frame part 10 can extend slightly over the adjacent rolling elements 6, which are held at a distance, in order to be able to support itself if necessary.

[0040] In particular, the intermediate piece 7 can have receiving spaces 11, 12 towards opposite end faces, cf. Figure 5which allow the spaced-apart rolling elements 6 to penetrate slightly into the space enclosed by the frame part 10 or into the intermediate piece body. The end edges 13 of the frame part 10 can be matched in their diameter or their clear width to the contour of the rolling element 6 to such an extent that the spaced-apart rolling elements 6 can support the frame part 10 against tilting.

[0041] As the Figure 2 and 3 show, the outer frame part 10 is provided with recesses 14 and has a rod or skeleton structure through which said recesses 14 extend. In particular, said skeleton structure of the frame part 10 can be formed by elongated, rod- or bone-like struts 16 and 17, which are connected to one another in a chain-like or polygonal manner and, overall, form a meandering skeleton structure that extends in the circumferential direction of the intermediate piece 7 or around the central section 8.

[0042] The skeleton structure of the frame part 10 can, in particular, comprise longitudinal struts 16, which are arranged spaced apart from one another in the circumferential direction and connected to one another in pairs by transverse struts 17. Said longitudinal struts 16 can extend approximately in the running direction or inclined at an acute angle thereto, while said transverse struts 17 extend substantially transversely to the running direction of the rolling element row.

[0043] A pair of adjacent longitudinal struts 16, together with a cross strut 17 connecting the two longitudinal struts 16, can form a U-shaped frame which encloses a recess 14.

[0044] The aforementioned recesses 14 can each be open toward an axial side, wherein advantageously, recesses 14 can be provided that are open alternately to the front and rear, so that the intermediate piece 7 comprises recesses 14 open toward each axial side. In particular, viewed in the circumferential direction of the intermediate piece 7, a recess 14 open toward a first axial side can alternate with a recess 14 open toward the opposite axial side. Adjacent recesses 14 face opposite sides with their openings.

[0045] In accordance with the meandering course of the skeleton structure of the frame part 10, the cross struts 17 are arranged alternately on opposite edge sections of the frame part 10, i.e., viewed in the running direction, once on a front edge section and once on a rear edge section, cf. Figure 3 .

[0046] Due to the skeletal, in particular meandering, design of the frame part 10, the frame part 10 has a shape-related structural elasticity, in particular through bending or deformation of the connecting sections acting as joints between the longitudinal and transverse struts 16, 17.

[0047] The connecting struts 9, which connect the central section 8 to the frame part 10, can advantageously be designed in the form of approximately rod-shaped spokes, which can have an at least approximately straight course. In particular, the spoke-shaped connecting struts 9 can extend in a radial plane transverse to the running direction of the row of rolling elements.

[0048] The connecting struts 9 can extend radially, cf. Figure 4. Regardless of this, 2 to 8, 3 to 6, or 4 to 5, for example, 4 spokes can be provided. This is sufficient to connect the frame part 10 to the central section 8 with sufficient stability and simultaneously creates space for the lubricant.

[0049] How Figure 4 As shown in Figure 1, the annular surface between the central section 8 and the frame part 10, which is bridged by the connecting struts 9, can comprise relatively large openings or material-free areas. For example, the connecting struts 9 can make up less than 50% or less than 30% of the aforementioned annular surface. In other words, viewed in the running direction, there are more openings than spokes.

[0050] The connecting struts 9 can advantageously be designed such that they do not come into contact with the rolling elements 6. For example, the central section 8 can protrude with its opposite abutting surfaces 18, 19 in the running direction or against the running direction beyond the aforementioned connecting struts 9. If one considers two - hypothetical - parallel planes that abut the opposite abutting surfaces 18 and 19 and extend perpendicular to the running direction of the row of rolling elements, the aforementioned connecting struts 9 can extend in the space between the two imaginary planes, cf. Figure 5 .

[0051] The connecting struts 9 can be thinner than the central section 8 when viewed in the running direction of the row of rolling elements, cf. Figure 5 .

[0052] The connecting struts 9 can each be attached to a central section of the frame part 10, so that the frame part 10 protrudes approximately the same distance towards opposite sides compared to the connecting struts 9. In particular, the connecting struts 9 can each be hinged approximately centrally to longitudinal struts 16, cf. Figure 2 and Figure 5 .

Claims

1. A rolling bearing having two concentric raceways (2, 3), between which there are provided, in a bearing gap (20), a plurality of rolling bodies (6) which roll on at least two tracks (4, 5), wherein intermediate pieces (7) which keep the rolling bodies (6) spaced apart from one another are provided between the rolling bodies (6), wherein the intermediate pieces (7) each comprise a central portion (8) which is connected via connecting struts (9) to an outer frame part (10) surrounding the central portion (8), characterized in that the central portion (8) in the direction of running of the rolling body row is formed individually to transmit force between the rolling bodies (6) that are to be kept spaced apart and / or the abutment surfaces that keep adjacent rolling bodies (6) spaced apart are formed individually on said central portion (8).

2. The rolling bearing according to the preceding claim, wherein the frame part (10) takes the form of a bar structure or skeleton structure with window-like and / or door arch-like cutouts (14), wherein the cutouts (14) are each formed to be open towards an end face of the intermediate piece (7) and are encompassed by a U-shaped frame part, in particular a U-shaped web frame.

3. The rolling bearing according to the preceding claim, wherein the cutouts (14) are alternately open towards opposite end faces of the intermediate piece (7) and are encompassed by frame struts (16, 17) forming a meandering skeletal structure in the circumferential direction of the intermediate piece (7).

4. The rolling bearing according to any of the preceding claims 2 or 3, wherein the frame part (10) annularly surrounds the central portion (8) and / or has a cylindrical, in particular a circularly cylindrical casing contour.

5. The rolling bearing according to any of the preceding claims 2 to 4, wherein the material portions of the frame part (10) between the cutouts (14) form less than 50% or less than 30% of the annular enveloping surface of the frame part (10) circumferentially enclosing the frame part (10) including the cutouts (14).

6. The rolling bearing according to any of the preceding claims 2 to 5, wherein the skeleton structure of the frame part (10) consists of substantially uniformly thin bar-shaped or bone-shaped struts (16, 17) which are connected to one another.

7. The rolling bearing according to the preceding claim, wherein the bar-shaped or bone-shaped struts (16, 17) of the skeleton structure comprise alternating longitudinal struts (16) and cross-struts (17).

8. The rolling bearing according to any of the preceding claims 2-7, wherein the frame part (10) projects outwardly beyond the central portion (8) towards both end faces of the intermediate piece (7) and / or has a length in the direction of running of the rolling body row which is more than twice the length of the central portion (18).

9. The rolling bearing according to any of the preceding claims 2-8, wherein the connecting struts (9) between the central portion (8) and the frame part (10) are connected to a middle portion of the frame part (10) between the end margins thereof and / or extend in a common plane perpendicular to the direction of running of the rolling body row.

10. The rolling bearing according to any of the preceding claims 2-9, wherein the connecting struts (9) between the central portion (8) and the frame part (10) take the form of bar-shaped spokes.

11. The rolling bearing according to any of the preceding claims 2-10, wherein the connecting struts (9) are formed thinner in the direction of running of the rolling body row than the central portion (8).

12. The rolling bearing according to any of the preceding claims, wherein the connecting struts (9) between the central portion (8) and the frame part (10) are formed free of contact with the rolling bodies (6).

13. The rolling bearing according to any of the preceding claims, wherein an annular area between the central portion (8) and the frame part (10) bridged by the connecting struts (9) is formed less than 50% or less than 30% by the connecting struts (9) and consists more than 50% or more than 70% of openings.

14. The rolling bearing according to any of the preceding claims, taking the form of an open centered large rolling bearing having a diameter greater than 0.5 m or greater than 1 m.