Double row roller bearing

Abstract

Double-row roller bearing (1), comprising an outer ring (2) and two inner rings (3, 4), and rolling elements (7) rolling between the outer ring (2) and the inner rings (3, 4), wherein the outer ring (2) provides rolling element raceways (8, 9) for both rows of rolling elements (5, 6) and each inner ring (3, 4) provides a rolling element raceway (10, 11), and wherein the outer ring (2) forms a central flange (12) between the rows of rolling elements (5, 6) and each inner ring (3, 4) forms a flange (14, 15) at a bearing end face, and wherein the roller bearing has a thrust surface (20) positioned on the outer circumferential surface of the inner rings (3, 4) between their rolling element raceways (10, 11) and holding the inner rings (3, 4) together by means of a snap connection. a center flange retaining clip (16) providing for the rolling elements (7) of both rows of rolling elements (5, 6), characterized in that the center flange retaining clip (16) extends into the inner rings (3,4) by means of snap lugs (17) offset alternately around the circumference into a groove-like recess of the inner rings (3, 4) and thus holds the inner rings (3, 4) together and has a lubrication groove (13) on the axial opposite side of a snap lug (17).

Description

[0001] The invention relates to a double-row roller bearing comprising a single outer ring and two inner rings according to the preamble of claim 1.

[0002] Such a roller bearing is known, for example, from DE 10 2016 211 630 A1. This is a double-row cylindrical roller bearing. Further roller bearings having the features of the preamble of claim 1 are described, for example, in documents DE 10 2017 111 044 A1 and DE 10 2013 220 702 A1. In these cases, they are tapered roller bearings.

[0003] DE 10 2016 204 459 A1 discloses a multi-row cylindrical roller bearing which has an intermediate ring arranged between two adjacent rows of cylindrical rollers. The intermediate ring has two axially outward-facing radial surfaces which are inclined in a defined manner to reduce the friction between these surfaces and the end faces of the cylindrical rollers.

[0004] In the case of a double-row bearing arrangement disclosed in WO 2011 / 029 764 A1, either two inner rings or two outer rings are formed in one piece. Between the other two bearing rings, i.e., those arranged side by side and each providing exactly one rolling element raceway, means are placed with which an axially acting preload force can be generated.

[0005] DE 10 2005 005 377 B4 describes a bearing outer ring comprising a ring body and a separate flange ring arranged in the region of a first axial end of the ring body. Optionally, flange rings are located on both end faces of the bearing. The flange ring is snapped into a contour of the ring body and is hardened at least in certain areas. Overall, the bearing described in DE 10 2005 005 377 B4 is a single-row cylindrical roller bearing.

[0006] Another bearing ring arrangement with a separate flange ring is known from DE 10 2013 202 736 A1. In this case, an additional retaining element is provided for fastening the flange ring in a bearing ring.

[0007] A possible design for a flange ring for a cylindrical roller bearing, tapered roller bearing or spherical roller bearing is described in DE 10 2016 219 789 A1. In this case, a base body of the flange ring is provided, at least in some areas, with a support layer formed from a metal.

[0008] Documents DE 198 55 539 A1, DD 32 999 A5 and CN 2 01 262 194 Y describe variants of rolling bearings which have several bearing rings arranged side by side, held together by annular retaining elements. In each of these cases, the annular retaining elements are significantly smaller than the bearing rings and are attached to the outer surface of the outer rings in such a way that the central axis of each annular retaining element intersects the axis of rotation of the rolling bearing orthogonally.

[0009] The invention is based on the objective of further developing a double-row roller bearing compared to the aforementioned prior art, particularly with regard to lubricant distribution and manufacturing aspects.

[0010] This problem is solved according to the invention by a double-row roller bearing with the features of claim 1. The roller bearing comprises, in a basic design known per se, a single outer ring and two inner rings, as well as rolling elements rolling between the outer ring and the inner rings. The outer ring provides raceways for both rows of rolling elements, while each of the inner rings forms a single raceway. The bearing rings have a total of three flanges. The outer ring forms a central flange between the rows of rolling elements. Each inner ring has exactly one flange. This flange is located on one end face of the roller bearing.

[0011] According to claim 1, a center-rim retaining clip, also referred to as a retaining ring, exists. This clip, positioned on the outer circumferential surface of the inner rings between their rolling element raceways, provides axial bearing surfaces for the rolling elements of both rows of rolling elements. The center-rim retaining clip engages the inner rings by means of alternately offset snap lugs in groove-like recesses of the inner rings, thus holding the inner rings together. The snap lugs are alternately offset in that they are distributed around the circumference of the center-rim retaining clip and exhibit an angular offset from each other around the circumference for the other inner ring. A lubrication groove is provided on the axial opposite side of each snap lug.

[0012] Together with an opening located at the joint between the inner rings, this allows for radial lubrication of the double-row roller bearing from the inside. The lubrication groove of the center retaining clip ensures particularly advantageous distribution of the lubricant directly into each row of rolling elements. Grease is particularly suitable as a lubricant. Oil lubrication of the roller bearing is also possible.

[0013] Alternatively or in addition to the lubrication openings in the inner rings and the retaining ring, at least one lubrication bore may be located on the outer ring. Such a lubrication bore may be arranged between the rows of rolling elements and thus penetrate the center flange of the outer ring.

[0014] Preferably, the centerboard retaining clip has a lubrication groove on the axial opposite side of each snap lug. This enables a particularly uniform lubricant distribution.

[0015] A double-row roller bearing can be either a cylindrical roller bearing or a tapered roller bearing. In both cases, the double-row roller bearing can function as a fixed bearing within a machine where a rotating part is supported by several bearings of different designs.

[0016] Provided the rollers of both rows of rolling elements are identically dimensioned, the double-row roller bearing, excluding the center retaining clip, can exhibit mirror symmetry with respect to a mirror plane located centrally between the two bearing faces. Minor deviations from mirror symmetry are possible if the arrangement of the two inner rings is a split bearing ring that was reassembled during bearing assembly. Otherwise, each inner ring is tangent to the aforementioned mirror plane. The two inner rings are typically designed as identical parts.

[0017] Materials suitable for manufacturing the centerboard retaining clip include metallic materials as well as plastics, including fiber-reinforced versions, although the retaining clip itself is not necessarily constructed from a single material. The retaining clip does not transmit axial operating loads but guides the rolling elements, thus helping to prevent excessive twisting of the rolling elements. However, regarding manufacturing, it has been found that the offset snap-in tabs make injection molding from plastic particularly advantageous, as the undercuts present from a manufacturing perspective can be demolded without forced demolding in the open / close direction. This also results in a simplified tool design for the injection molding process.Since no undercuts need to be forced demolded, the overlap height can be variably adjusted, thus allowing for significantly greater design freedom. This design also offers advantages for machining, as the tools for forming the retaining lugs require less swing-out. This also results in substantial improvements for 3D printing.

[0018] If multiple lubrication grooves are present, they are arranged alternately. This eliminates the need for radial slides in the injection mold during manufacturing, thus saving on tooling costs and avoiding complex contact geometries. From a functional perspective, the lubrication grooves offer the advantage of simplified relubrication due to the larger lubricant reservoir, which delivers the lubricant directly to the rolling element rows / interlocking surfaces. Furthermore, the grooves also serve to create targeted ovalization during retainer ring assembly onto the inner rings, thereby reducing assembly forces and component stress while simultaneously enabling higher contact ratios between the retainer ring and inner ring. The elimination of lubrication holes in the center retainer clip simplifies subsequent machining, as purely radial machining is no longer necessary.

[0019] This also offers advantages in a conceivable 3-stage printing process, as less support structure is required, which would otherwise have to be removed manually.

[0020] Furthermore, the increased flexibility achieved through the lubrication grooves and reciprocal retaining lugs allows for a higher radial height of the retaining ring, which increases the rolling element guide surface and is advantageous in terms of guiding behavior.

[0021] Furthermore, the centerboard retaining clamp serves as a transport safety device.

[0022] When assembling the double-row roller bearing, the retaining ring is first snapped onto one of the two inner rings. Together with a row of rolling elements, the inner ring and retaining ring can then be inserted into the outer ring until the rolling elements contact the center flange of the outer ring. In this position, the second inner ring, along with the second row of rolling elements, can be inserted into the outer ring until the retaining ring snaps into place on the second inner ring. The retaining ring can be either a closed or an open ring.

[0023] Compared to double-row bearings, in which inner ring components are held together by an internally mounted, plastically deformable sheet metal retaining ring, the patented double-row roller bearing is characterized by reduced assembly effort. In particular, plastic deformation of metallic retaining elements is eliminated. Furthermore, because the retaining ring is mounted externally on the inner rings, the aforementioned rolling element guidance can be performed as an additional function of the retaining ring.

[0024] The double-row roller bearing is particularly suitable as a pulley bearing, capable of absorbing high radial and axial forces. Mobile applications, such as in rail vehicles, are also possible. The rolling elements of the roller bearing can be guided in a cage. Otherwise, the double-row roller bearing is a full complement bearing.

[0025] In comparison to inner rings with two flanges, the inner rings of the roller bearing according to the application, each with only a single flange, are of a significantly simpler design. Optionally, the rolling bearing, designed as a double-row roller bearing, is sealed on one or both sides.

[0026] An embodiment of the invention is explained in more detail below with reference to a drawing. The drawing shows: Fig. 1. A double-row roller bearing, namely cylindrical roller bearing, in a cutaway perspective view. Fig. 2 the roller bearing after Fig. 1 in another view, Fig. 3 a perspective view of the centerboard retaining clip 16.

[0027] A rolling bearing, designated by reference numeral 1, is constructed as a double-row roller bearing and is used in a pulley bearing, with the roller bearing 1 functioning as a fixed bearing. The roller bearing 1 comprises an outer ring 2 and two inner rings 3, 4. The two rows of rolling elements in the roller bearing 1 are designated 5, 6. Each row of rolling elements 5, 6 comprises numerous cylindrical rollers as rolling elements 7. The rollers 7, i.e., cylindrical rollers, are not guided in a cage in this case. That is, the rolling bearing 1 is designed as a full complement bearing. The raceways on the outer ring 2 are designated 8, 9, and the raceways on the inner rings 3, 4 are designated 10, 11.

[0028] A central flange 12 is located between the rows of rolling elements 5 and 6 on the outer ring 2. The outer ring 2 has no flanges on the end faces of the roller bearing 1. Seals 19 can be provided for sealing the bearing, as shown in the figures.

[0029] In contrast to the outer ring 2, the inner rings 3, 4 have flanges 12, 14, 15 located on the end faces of the roller bearing 1. Axial forces between the outer ring 2 and one of the inner rings 3, 4 can be transmitted via the flanges 12, 14, 15. In a manner known per se, the flanges 12, 14, 15 serve to guide the rolling elements 7.

[0030] If an axial force is exerted on the outer ring 2, which, with reference to the arrangement according to the Fig. 1 and Fig. 2, acting from left to right, this force loads exclusively the edge 15 of the right inner ring 4. Similarly, an axial force applied from the right to the outer ring 2 loads exclusively the edge 14 of the left inner ring 3.

[0031] In addition to the center rim 12, there is, in this case, a center rim retaining clip 16 made of plastic, which is also referred to as a retaining ring and holds the two inner rings 3, 4 together, thus serving primarily as a transport safety device. No axial force is transmitted between the outer ring 2 on the one hand and either of the inner rings 3, 4 on the other via the retaining ring 16. Therefore, despite visual similarities, the function of the retaining ring is not comparable to the function of the center rim 12.

[0032] The centerboard retaining clip 16 shows, as can be seen from the Fig. 1 and Fig. As shown in Figure 2, on each side of the inner rings 3 and 4, there are snap-on lugs 17 that are alternately offset. The snap-on lugs 17 are alternately offset in that they are distributed over the circumference of the center retaining clip 16 and have an angular offset from each other over the circumference for the other inner ring. The snap-on lugs 17 engage in annular grooves 18, each of which is formed by one of the inner rings 3 and 4. Analogous to the snap-on lugs 17, the annular grooves 18 do not necessarily extend over the entire circumference of the inner rings 3 and 4. A lubrication groove 13 is provided on the axial opposite side of the snap-on lug 17.

[0033] The lubrication grooves 13 of the center retaining clip 16, in conjunction with an opening 21 in the inner rings 3, 4, ensure ideal lubrication of the bearing. Particularly good lubricant distribution is guaranteed when the opening 21 in the inner rings 3, 4 is aligned with the lubrication grooves 13 of the center retaining clip 16. The lubricant is thus distributed to the two rows of rolling elements 5, 6. The end faces of the retaining ring 16, designated 20, serve as contact surfaces for the end faces of the rolling elements 7, i.e., cylindrical rollers.

[0034] Fig.Figure 3 shows the centerboard retaining clip 16 in a perspective view. The snap lugs 17 are partially distributed alternately around the circumference. The retaining ring itself is closed. This closed design provides robust rigidity. At the same time, the alternating snap lugs 17 allow for larger overlaps compared to known solutions, as the retaining ring no longer needs to be fully expanded during assembly of the inner ring. Instead, the retaining ring ovalizes, reducing the load during assembly and resulting in lower edge fiber strain in the material and thus reduced stress. The lubrication grooves 13 are also arranged alternately. Reference symbol list 1 Roller bearing, rolling bearing 2 outer ring 3 inner ring 4 inner ring 5 row of rolling elements 6 row of rolling elements 7 rolling elements, roller 8 Rolling element raceway on the outer ring 9 Rolling element raceway on the outer ring 10 Rolling element raceway on the inner ring 11 Rolling element raceway on the inner ring 12 Midboard 13 Lubrication groove 14. Edge of the inner ring 3 15 Edge of the inner ring 4 16 Centerboard retaining clip, retaining ring 17 snappy noses 18 Ring groove 19 Seal 20 axial approach surface 21 Opening formed by the inner rings

Claims

[1] Double-row roller bearing (1) with an outer ring (2) and two inner rings (3, 4), and rolling elements (7) rolling between the outer ring (2) and the inner rings (3, 4), wherein the outer ring (2) provides rolling element raceways (8, 9) for both rows of rolling elements (5, 6) and each of the inner rings (3, 4) provides a rolling element raceway (10, 11), and wherein the outer ring (2) forms a central flange (12) between the rows of rolling elements (5, 6) and each inner ring (3, 4) forms a flange (14, 15) at a bearing end face, and wherein the roller bearing has a thrust surface on the outer circumferential surface of the inner rings (3, 4) between their rolling element raceways (10, 11) which holds the inner rings (3, 4) together by means of a snap connection. (20) has a center retaining clip (16) providing for the rolling elements (7) of both rows of rolling elements (5, 6), characterized by, that the center rim retaining clip (16) engages in the inner rings (3, 4) by means of snap lugs (17) offset alternately around the circumference into a groove-like recess of the inner rings (3, 4) and thus holds the inner rings (3, 4) together and has a lubrication groove (13) on the axial opposite side of a snap lug (17). [2] Roller bearing (1) according to claim 1, characterized by , that the centerboard retaining clip (16) has a lubrication groove (13) on the axial opposite side of each snap lug (17). [3] Roller bearing (1) according to claim 1 or 2, characterized by that this is designed as a cylindrical roller bearing. [4] Roller bearing (1) according to claim 1 or 2, characterized by that this is designed as a tapered roller bearing. [5] Roller bearing (1) according to any one of claims 1 to 4, characterized by , that the centerboard retaining clip (16) is made of metal. [6] Roller bearing (1) according to any one of claims 1 to 4, characterized by, that the centerboard retaining clip (16) is made of plastic. [7] Roller bearing (1) according to any one of claims 1 to 6, characterized by , that the centerboard retaining clip (16) is designed as a closed ring. [8] Roller bearing (1) according to any one of claims 1 to 7, characterized by , that the centerboard retaining clip (16) is designed as an open ring. [9] Use of a roller bearing (1) according to claim 1 or 2 in a pulley bearing.

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