Axial-radial plain bearings

Abstract

An axial-radial plain bearing (10) comprising at least a first and a second bearing element (20, 30) which are mounted coaxially relative to one another and rotatably about a bearing axis (12), at least one polymer sliding element (70) which is arranged between the bearing elements (20, 30) and which has radial and axial sliding surfaces for radial and axial decoupling of the bearing elements (20, 30), wherein at least the first bearing element (20) is formed in several parts and the second bearing element (30) is guided at least in sections in at least one sliding channel (73) of the polymer sliding element (70), which is formed between bearing parts of the first bearing element (20) which are connected to one another in a rotationally fixed manner, characterized in that the first bearing element (20) comprises an arrangement of bearing disks (21, 22) and / or bearing disk segments which are connected to one another in a rotationally fixed manner and which axially enclose at least one spacer ring (40) or at least one spacer ring segment between them,which is designed to form at least one at least partially circumferential groove channel (11) which accommodates at least one polymer sliding element (70) for rotatably guiding the second bearing element (30).

Description

[0001] The invention relates to an axial-radial plain bearing, in particular a rotary table bearing, comprising at least a first and a second bearing element which are mounted coaxially relative to one another and rotatably about a bearing axis, at least one polymer sliding element which is arranged between the bearing elements and which has radial and axial sliding surfaces for the radial and axial decoupling of the bearing elements, wherein at least the first bearing element is designed in several parts and the second bearing element is guided at least in sections in at least one sliding channel of the polymer sliding element, wherein the sliding channel is formed between bearing parts of the first bearing element which are connected to one another in a rotationally fixed manner.

[0002] Such axial-radial plain bearings are designed to absorb both axial and radial forces and are used, for example, in rotary indexing tables, dividing heads, for the design of CNC rotary axes, etc. The advantages of such plain bearings include, in particular, the low friction between the bearing elements, maintenance-free operation, cost-effective production, robust construction, and high wear resistance. The multitude of these advantages has resulted in the increased use of such bearings, particularly those designed as polymer rotary table bearings (PRT), in a wide variety of applications.

[0003] An axial-radial plain bearing of the aforementioned type is known, for example, from DE 10 2021 125 527 A1. The axial-radial plain bearing described in this publication has a first bearing ring and a second bearing ring, wherein the bearing rings are arranged to rotate relative to one another about a bearing axis, and the second bearing ring forms a substantially U-shaped cross-section to accommodate the first bearing ring at least in sections. The known axial-radial plain bearing comprises sliding elements made of a polymer optimized for tribological purposes. Such polymers are generally also referred to as tribopolymers.

[0004] For a wide range of rotary table bearing applications, a low overall height is desirable. Certain applications require particularly small and lightweight components. Furthermore, there is a fundamental need for rotary table bearings with a simple design.

[0005] In the rotary table bearing described in DE 10 2021 125 527 A1, as in many other known rotary table bearings, the bearing elements or bearing rings are intended to be manufactured from metal parts, for example from turned parts.

[0006] Typically, the bearing rings are designed to have two spaced-apart bearing disc sections and at least one bearing cylinder section arranged between the two bearing disc sections and associated with a bearing ring, optionally formed integrally with the bearing ring. This cylinder section, together with the bearing disc sections of one bearing element, forms a U-shaped receiving channel for the other bearing element. This arrangement largely determines the dimensions and structure of the rotary table bearing.

[0007] The invention is based on the object of providing a structurally simplified rotary table bearing which is easy to manufacture and has a particularly low overall height.

[0008] The object underlying the invention is achieved by a rotary table bearing having the features of claim 1. Advantageous embodiments of the invention emerge from the subclaims.

[0009] According to one aspect of the invention, an axial-radial plain bearing is provided which comprises at least a first and a second bearing element, wherein the bearing elements are mounted coaxially relative to one another and rotatably about a bearing axis, the axial-radial plain bearing further comprising at least one polymer sliding element which is arranged between the bearing elements and which has radial and axial sliding surfaces for the radial and axial decoupling of the bearing elements, wherein at least the first bearing element is designed in several parts and the second bearing element is guided at least in sections in at least one sliding channel of the polymer sliding element which is arranged between bearing parts of the first bearing element which are connected to one another in a rotationally fixed manner.

[0010] The axial-radial plain bearing according to the invention is characterized in particular in that the first bearing element has an arrangement of bearing discs and / or bearing disc segments connected to one another in a rotationally fixed manner, which axially enclose at least one spacer ring or at least one spacer ring segment between them, which is designed to form at least one at least partially circumferential groove channel which accommodates at least one polymer sliding element for the rotatable guidance of the second bearing element.

[0011] The axial-radial plain bearing according to the invention can, for example, be composed of a particularly simple structure consisting of stacked discs and / or rings of different diameters, forming a particularly compact package and can be designed, for example, as simple metal stampings, laser-cut metal parts, in particular laser-cut metal sheets, or metal castings. Such parts are simpler and cheaper to manufacture than metal turned parts with shoulders or recesses.

[0012] Such a rotary table bearing can, in a particularly advantageous manner, comprise metal parts that are designed as identical parts, which ensures both a low installation height and simple production.

[0013] The designation of surfaces of the plain bearing according to the invention or of its components as axial surfaces refers to surfaces whose surface normal runs essentially in the axial direction or which extend essentially perpendicular to the axial direction of the bearing or to the bearing axis or rotational axis of the bearing. Similarly, a radial surface of the bearing or one of its components extends essentially parallel to the rotational axis of the bearing. In this way, the outer surface of a cylinder is to be referred to as a radial surface to which a radius vector is perpendicular.

[0014] The bearing elements can be designed, for example, as bearing discs made of aluminum. The spacer ring or several spacer ring segments, preferably complementing each other to form a closed ring, can also be designed as aluminum components.

[0015] The at least one polymer sliding element can, for example, be formed from a thermoplastic material filled with a sliding material.

[0016] In particular, the fact that the axial-radial plain bearing is, in the simplest case, composed of a package of essentially flat metal discs which are radially and axially decoupled from one another by at least one polymer sliding element makes it possible to provide a particularly light, simple and compact plain bearing.

[0017] In a preferred variant of the axial-radial plain bearing according to the invention, it is provided that the spacer ring is connected in a rotationally fixed manner to at least one, preferably to both, bearing discs arranged at a distance from one another, which form between them a circumferential, preferably U-shaped groove channel which is open radially outwards and is delimited on the inside by a circumferential surface of the spacer ring.

[0018] Preferably, the spacer ring and the bearing discs comprise fastening means extending parallel to one another, preferably in the form of threaded bolts, by means of which the bearing discs are axially clamped against the spacer ring, preferably in the installed position of the axial-radial plain bearing.

[0019] The fastening means are preferably arranged at a regular and uniform angular distance over the circumference of the bearing discs of the spacer ring on a common bolt circle.

[0020] The sliding channel formed by the at least one polymer sliding element preferably has an approximately U-shaped, preferably radially outwardly open, cross-sectional profile which encompasses the second bearing element, wherein a radial bearing section or a radial bearing surface decouples the second bearing element from the spacer ring and two axial bearing sections or axial bearing surfaces decouple the second bearing element from the bearing discs of the first bearing element.

[0021] The at least one polymer plain bearing preferably forms both axial bearing surfaces and at least one radial bearing surface, with the groove base of the U-shaped cross-sectional profile preferably extending axially and forming a radial bearing that decouples the second bearing element from the spacer ring. The two legs of the U-profile each form axial bearing sections that decouple the second, preferably also disk-shaped, bearing element from the bearing disks of the first bearing element.

[0022] Particularly preferably, the axial-radial plain bearing according to the invention comprises a plurality of polymer sliding elements, which are preferably distributed over the circumference of the bearing axis. These can, for example, form partial circle segments of the sliding channel encircling the bearing axis.

[0023] The polymer sliding elements can, for example, be designed as profile segments with a U-shaped cross section, in particular in the manner of a clamp, a plurality of which can be inserted into the groove channel formed between the bearing discs.

[0024] The profile segments can be inserted into the groove channel without any connection to one another, largely without gaps, whereby they do not necessarily have to lie against one another radially outwards, but can fan out to form gussets, i.e. wedge-shaped spaces.

[0025] During assembly of the axial-radial plain bearing according to the invention, the profile segments can, for example, have been previously placed onto the second bearing element, which preferably forms a receiving ring for a connecting component, wherein the legs of the U-shaped profile segments engage around axial surfaces of the receiving ring.

[0026] The axial-radial plain bearing according to the invention is advantageously designed so that the individual parts can be assembled into a sandwich-like package. The second bearing element, pre-assembled with the profile segments, can be inserted between the bearing discs during assembly, which are connected to one another via fastening means, in particular via fastening means penetrating the bearing discs and the spacer ring.

[0027] The legs of the U-shaped profile segments advantageously have a flexibility that allows the bearing clearance to be adjusted via the selected thickness of the spacer ring and / or the selected preload of the fastening means when installing the axial-radial plain bearing.

[0028] As mentioned above, the polymer sliding elements can alternatively be designed as individual partial circle segments that form a circumferential sliding channel. At least some partial circle segments can be connected to one another, for example, via radially extending film hinges. The number of partial circle segments can be selected to suit any desired division of a full circle into different partial circles. For example, it would be possible to provide a single polymer sliding element in the form of a ring open on only one side.

[0029] The polymer sliding elements are preferably formed at least partially from a tribopolymer. These can, for example, be formed from an injection-molded thermoplastic filled with a solid lubricant.

[0030] The axial-radial plain bearing according to the invention may comprise a single one-piece spacer ring, the thickness of which is greater than the clear width of the sliding channel and which preferably has a smaller outer diameter than the bearing discs and which further preferably forms a continuously circumferential groove channel between the bearing discs.

[0031] Preferably, the bearing discs of the first bearing element are designed as head discs of the axial-radial plain bearing and the second bearing element is preferably designed as a receiving ring with fastening means for fastening a component.

[0032] The bearing discs are preferably designed as substantially flat discs, meaning that their thickness is significantly smaller than their width. The bearing discs can have the same inner diameter and the same outer diameter.

[0033] The spacer ring can have a greater thickness and a smaller width than the bearing discs. For the purposes of the present invention, thickness refers to the axial dimension, while width refers to the radial extent.

[0034] Advantageously, the bearing discs and the receiving ring of the axial-radial plain bearing according to the invention are designed as metal components, preferably made of stainless steel or aluminum.

[0035] The axial-radial plain bearing according to the invention advantageously comprises exactly four parts which form the bearing elements as well as the polymer sliding elements arranged between the bearing elements.

[0036] The invention is explained below with reference to and with reference to an embodiment shown in the accompanying drawings.

[0037] They show: Fig. 1: a perspective view of the axial-radial plain bearing according to the invention; Fig. 2: a sectional view along a central cross section through the axial-radial plain bearing according to the invention; Fig. 3: a perspective view of parts of the axial-radial plain bearing according to the invention; Fig. 4: a perspective view of a polymer sliding element of the axial-radial plain bearing according to the invention; and Fig. 5: another perspective view of parts of the axial-radial plain bearing according to the invention.

[0038] The axial-radial plain bearing 10 according to the invention comprises a first and a second bearing element 20, 30, wherein the first bearing element and the second bearing element 20, 30 are guided and mounted coaxially and rotatably relative to one another. The annular disk-shaped bearing elements 20, 30 are rotatable relative to one another about a common bearing axis 12. The bearing axis 12 defines the axial direction of the axial-radial plain bearing 10.

[0039] The first and the second bearing element 20, 30 form a circumferential and radially outwardly open groove channel 11, in which the second bearing element 30 is guided rotatably relative to the first bearing element 20.

[0040] The first bearing element 20 is constructed in several parts and comprises a first and second bearing disc 21, 22, which are connected to one another in a rotationally fixed manner by fastening means (not shown), for example by threaded bolts, with the interposition of a spacer ring 40. The bearing discs 21, 22 are designed as essentially flat discs, i.e., their thickness is significantly smaller than their width. The bearing discs 21, 22 each have the same inner diameter and the same outer diameter and each comprise a first bolt circle 50 with fastening bores 51, wherein the bolt circles 50 of the first and second bearing discs correspond to one another.

[0041] The spacer ring 40 comprises a corresponding hole circle 50 with corresponding fastening bores 51. The spacer ring 40 generally preferably has a greater thickness and / or a smaller width than the bearing discs 21, 22. In the sense of the present invention, the thickness refers to the axial dimension, and the width refers to the radial extent.

[0042] The thickness of the spacer ring 40 determines the clear width of the grooved channel 11, in which the second bearing element 30 is rotatably guided. The second bearing element 30 is designed as an annular disc or an annular disc-shaped receiving ring for a connecting component to be rotatably mounted. The first and second bearing discs 21, 22 each form the end plates of the axial-radial plain bearing 10, which is designed as a polymer rotary table bearing.

[0043] The second bearing element 30 is decoupled both axially and radially from the first bearing element 20 and the spacer ring 40 within the groove channel 11 via polymer sliding elements 70. The second bearing element 30, which is designed as a receiving ring for a connecting component, comprises a second bolt circle 60 with second receiving bores 61 for fastening means of the connecting component.

[0044] Fig. 3 shows a perspective view of the axial-radial plain bearing according to the invention, in which the second bearing disc 22 of the first bearing element 20 and the second bearing element 30 as well as some of the polymer sliding elements 70 are not shown for the sake of illustration.

[0045] The polymer sliding elements 70 have a configuration as shown in the perspective view according to Fig. 4. These are designed as U-profile segments with two legs 71, which are connected to each other via a profile web 72. These are, as can be seen in particular from the illustration in Fig. 3, are inserted into the groove channel 11 without being connected to one another and form a radially outwardly open sliding channel 73, in which, as shown in Fig. 5, the second bearing element 30 is inserted.

[0046] Fig. Figure 5 shows a perspective view of the axial-radial plain bearing 10 according to the invention, which is similar to the view in Fig. 3, wherein the second bearing disc 22 and some of the polymer sliding elements 70 are not shown for reasons of simplification.

[0047] The legs 71 of the polymer sliding elements 70 each engage around axial surfaces 31 of the second bearing element 30. In the installed position, the profile web 72 of the polymer sliding elements 70 rests against a radial surface / circumferential surface 41 of the spacer ring 40. The profile web 72 of the polymer sliding elements 70 thus forms a radial bearing surface, whereas the legs 72 of the polymer sliding elements each form axial bearing surfaces. List of reference symbols 10 axial-radial plain bearings 11 Groove channel 12 bearing axle 20 first bearing element 21 first bearing disc 22 second bearing disc 30 second bearing element 31 Axial surface 40 spacer ring 41 Radial bearing surface 50 first bolt circle 51 mounting holes 60 second bolt circle 61 mounting holes 70 polymer sliding elements 71 legs 73 profile webs 73 axial bearing surfaces QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 125 527 A1 [0003, 0005]

Claims

[1] Axial-radial plain bearing (10) comprising at least a first and a second bearing element (20, 30) which are mounted coaxially relative to one another and rotatably about a bearing axis (12), at least one polymer sliding element (70) which is arranged between the bearing elements (20, 30) and which has radial and axial sliding surfaces for radial and axial decoupling of the bearing elements (20, 30), wherein at least the first bearing element (20) is formed in several parts and the second bearing element (30) is guided at least in sections in at least one sliding channel (73) of the polymer sliding element (70), which is formed between bearing parts of the first bearing element (20) connected to one another in a rotationally fixed manner, characterized byin that the first bearing element (20) comprises an arrangement of bearing discs (21, 22) and / or bearing disc segments which are connected to one another in a rotationally fixed manner and which axially enclose at least one spacer ring (40) or at least one spacer ring segment which is designed to form at least one at least partially circumferential groove channel (11) which receives at least one polymer sliding element (70) for the rotatable guidance of the second bearing element (30). [2] Axial-radial plain bearing (10) according to claim 1, characterized by that the spacer ring (40) is connected in a rotationally fixed manner to at least one, preferably two bearing discs (21, 22). [3] Axial-radial plain bearing (10) according to one of claims 1 or 2, characterized byin that the spacer ring (40) and two bearing discs (21, 22) are connected in a rotationally fixed manner by means of fastening means extending parallel to the bearing axis (12), preferably in the form of threaded bolts, wherein the fastening means are preferably arranged at a regular and equal angular distance over the circumference of the bearing discs (21, 22) and the spacer ring (40) on a common hole circle (50). [4] Axial-radial plain bearing (10) according to one of claims 1 to 3, characterized bythat the at least one polymer sliding element forms at least one sliding channel (73) and that preferably the sliding channel (73) of the at least one polymer sliding element (73) has an approximately U-shaped cross-sectional profile which encompasses the second bearing element (30), wherein a radial bearing surface of the polymer sliding element (70) decouples the second bearing element (30) from the spacer ring (40) and two axial bearing surfaces decouple the second bearing element (30) from the first bearing element (20), in particular from the bearing disks (20, 21). [5] Axial-radial plain bearing (10) according to one of claims 1 to 4, comprising a plurality of polymer sliding elements (70) which are arranged distributed over the circumference of the bearing axis (12). [6] Axial-radial plain bearing (10) according to claim 5, characterized by that the polymer sliding elements (70) form partial circle segments of the sliding channel (73) circulating around the bearing axis (12). [7] Axial-radial plain bearing (10) according to one of claims 1 to 6, characterized by that the polymer sliding elements (70) are at least partially formed from a tribopolymer. [8] Axial-radial plain bearing (10) according to one of claims 1 to 7, characterized by that the polymer sliding elements (70) form partial circle segments. [9] Axial-radial plain bearing (10) according to one of claims 1 to 8, characterized by a single one-piece spacer ring (40), the thickness of which is greater than the clear width of the sliding channel (73), which preferably has a smaller diameter than the bearing discs (21, 22) and which further preferably forms a continuously circumferential groove channel (11) between the bearing discs. [10] Axial-radial plain bearing (10) according to one of claims 1 to 9, characterized by that the thickness of the spacer ring (40) determines an axial bearing clearance. [11] Axial-radial plain bearing (10) according to one of claims 1 to 10, characterized bythat the bearing discs (21, 22) of the first bearing element (20) are designed as head discs of the axial-radial plain bearing (10) and that the second bearing element (30) is designed as a receiving ring with fastening holes for fastening a connecting component.

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