Axial-radial sliding bearing

Abstract

The invention relates to axial-radial sliding bearings (10) comprising at least a first and a second bearing element (20, 30) mounted coaxially relative to one another and rotatably about a bearing axis (12), and at least one polymer sliding element (70) which is located between the bearing elements (20, 30) and 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) has a multi-part form and the second bearing element (30) is at least partly guided in at least one sliding channel (73) of the polymer sliding element (70), the sliding channel being formed between bearing parts of the first bearing element (20) that are interconnected for conjoint rotation, characterized in that the first bearing element (20) comprises an arrangement of bearing discs (21, 22) and / or bearing-disc segments that are interconnected for conjoint rotation and axially between them enclose at least one spacer ring (40) or at least one spacer-ring segment designed to form at least one groove channel (11), which runs at least partially around the circumference and accommodates at least one polymer sliding element (70) for rotatable guidance of the second bearing element (30).

Description

[0001] Axial-radial sliding bearings

[0002] 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, also called a plastic 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.

[0003] 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 are particularly evident in the low friction between the bearing elements, maintenance-free operation, inexpensive production, robust construction, and high wear resistance. The multitude of these advantages has resulted in the increased use of such bearings, particularly axial-radial plain bearings designed as polymer rotary table bearings (PRT), in a wide variety of fields.

[0004] An axial-radial plain bearing of the type mentioned above 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 in order 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.

[0005] For many applications, a low overall height of the rotary table bearing is desirable. Certain applications require particularly small and lightweight components. Furthermore, there is a fundamental need for rotary table bearings to be structurally simple.

[0006] 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.

[0007] 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, which, 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.

[0008] 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.

[0009] 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.

[0010] 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 rotatable 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. The polymer sliding element can, for example, be a sliding element which is made from tribologically optimized plastic.

[0011] The axial-radial plain bearing according to the invention is characterized in particular in that the first bearing element has an arrangement of rotationally interconnected bearing discs and / or bearing disc segments which axially enclose between them at least one spacer ring or at least one spacer ring segment 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.

[0012] The axial-radial plain bearing according to the invention can, for example, have a particularly simple structure composed of stacked discs and / or rings of different diameters, which form 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 steps or recesses.

[0013] Such a rotary table bearing can, in a particularly advantageous manner, comprise metal parts which are designed as identical parts, which ensures both a low overall height and simple production. For example, the bearing disks can be designed as identical parts. For example, the bearing disks can each be made from a metal sheet, for example each be cut from a sheet metal, for example by means of punching or laser cutting. For example, the bearing disks can have the same thickness, i.e. extension along the bearing axis, or each be made from a metal sheet which each has the same thickness.For example, the spacer ring may have a thickness which is less than 20 times, in particular less than 10 times, in particular less than 5 times, and more than 1.5 times, in particular more than 2 times, in particular more than 3 times the thickness of the spacer rings.

[0014] The designation of surfaces of the plain bearing according to the invention or of its components as axial surfaces means 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 axis of rotation of the bearing. In a corresponding manner, a radial surface of the bearing or of one of its components extends essentially parallel to the axis of rotation 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.

[0015] The bearing elements can, for example, be designed as bearing discs made of aluminum. The spacer ring or several spacer ring segments, preferably complementing one another to form a closed ring, can also be designed as aluminum components.

[0016] The at least one polymer sliding element can, for example, be made from a thermoplastic plastic filled with a sliding material or from a tribologically optimized plastic or from a tribologically optimized polymer. Such a tribologically optimized polymer is a polymer optimized with regard to wear reduction and friction reduction. Such a polymer usually has a base polymer, for example the thermoplastics polyethylene, polypropylene, polyacetal, polycarbonate, polyamide, polyvinyl chloride, polytetrafluoroethylene and, in the case of thermosets, phenolic resins. Lubricants, in particular finely divided solid lubricants, for example molybdenum disulfide or graphite, and / or fillers, for example plastic or textile fibers or particles, are added to this base polymer.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] The fastening means are preferably arranged at a regular and uniform angular spacing over the circumference of the bearing disks of the spacer ring on a common bolt circle. The sliding channel formed by the at least one polymer sliding element preferably has an approximately U-shaped, preferably radially outwardly opening, 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 disks of the first bearing element.

[0021] The at least one polymer sliding element generally preferably forms both axial bearing surfaces and at least one radial bearing surface for the second bearing element. The polymer sliding element preferably bears against the spacer ring with a first radial bearing surface and against the second bearing element with a second radial bearing surface radially opposite this, such that the two opposite radial bearing surfaces of the polymer sliding element enable sliding with as little friction as possible between the spacer ring and the second bearing element. The polymer sliding element extends radially between the aforementioned radial bearing surfaces, such that it extends radially between the spacer ring and the second bearing element.Accordingly, the sliding friction present between the spacer ring and the second bearing element when the two bearing elements rotate relative to one another is determined by the sliding pairing “spacer ring polymer sliding element” on the one hand and by the sliding pairing “second bearing element polymer sliding element” on the other. The polymer sliding element preferably has axially opposite axial bearing surfaces for the second bearing element, between which the second bearing element is arranged, wherein it has a further axial bearing surface on its axial upper side and on its axial lower side, with which it bears against one of the two bearing disks of the first bearing element.The polymer sliding element thus extends axially, on the one hand, between a first of the bearing discs and the second bearing element, and also between the second bearing disc and the second bearing element, so that sliding friction during rotation of the two bearing elements relative to one another is defined, on the one hand, by the sliding pairing of the polymer sliding element and the bearing discs, and, on the other hand, by the sliding pairing between the polymer sliding element and the second bearing element. In general, it should be noted that the present explanations regarding a polymer sliding element can apply to each of the polymer sliding elements when multiple polymer sliding elements are provided.

[0022] In one embodiment, the sliding channel formed by the polymer sliding element has an approximately U-shaped, preferably radially outwardly opening, cross-sectional profile, wherein the groove base of the U-shaped cross-sectional profile extends axially and forms 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.

[0023] Particularly preferably, the axial-radial plain bearing according to the invention comprises a plurality of polymer sliding elements that are preferably distributed over the circumference of the bearing axis. These can, for example, form partial circle segments of the sliding channel that encircles the bearing axis.

[0024] The polymer sliding elements can be used, for example, as

[0025] Cross-section U-shaped profile segments, in particular in the manner of a clamp, can be formed, a large number of which can be inserted into the groove channel formed between the bearing discs.

[0026] 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.

[0027] During assembly of the axial-radial plain bearing according to the invention, the profile segments can, for example, have been previously placed on 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.

[0028] The axial-radial plain bearing according to the invention is advantageously designed so that the individual parts can be assembled into a package in the manner of a sandwich. The second bearing element, pre-assembled with the profile segments, can be inserted during assembly between the bearing discs, which are connected to one another via fastening means, in particular via fastening means penetrating the bearing discs and the spacer ring.

[0029] The legs of the U-shaped profile segments advantageously have a flexibility that allows the selected thickness of the spacer ring and / or the selected pre-tension of the fastening means during

[0030] Installation of the axial-radial plain bearing to adjust the bearing clearance.

[0031] 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 correspond to 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 that is open on only one side.

[0032] 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.

[0033] The axial-radial plain bearing according to the invention can 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.

[0034] 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.

[0035] The bearing discs are preferably designed as substantially flat discs, i.e., their thickness is significantly smaller than their width. The bearing discs can have the same inner diameter and the same outer diameter.

[0036] The spacer ring can have a greater thickness and a smaller width than the bearing discs. For the purposes of the present invention, the thickness refers to the axial dimension, and the width refers to the radial extent.

[0037] 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.

[0038] The axial-radial plain bearing according to the invention expediently comprises exactly four parts which form the bearing elements as well as the polymer sliding elements arranged between the bearing elements.

[0039] The invention further relates to a method for producing an axial-radial plain bearing which comprises at least a first and a second bearing element which are mounted coaxially relative to one another and rotatably about a bearing axis. In the axial-radial plain bearing produced by means of the method, at least one polymer sliding element is arranged between the bearing elements, said element having radial and axial sliding surfaces for radially and axially decoupling the bearing elements from one another. At least the first bearing element is constructed 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 formed between bearing parts of the first bearing element which are connected to one another in a rotationally fixed manner. The second bearing element is designed in the manner of a ring which has a central annular recess, as is of course usual for a ring.The first bearing element can comprise the two bearing discs and the spacer ring described above, wherein each of the two bearing discs and the spacer ring is preferably designed in the manner of a ring, each with a central annular recess. Generally, the second bearing element preferably projects radially beyond the first bearing element.In the method according to the invention, the at least one polymer sliding element is slipped onto the second bearing element from the annular recess of the second bearing element, the second bearing element with the slipped-on polymer sliding element is then placed onto a first bearing disk of the first bearing element and a second bearing disk of the first bearing element is then fixed to the first bearing disk, as a result of which a groove channel is formed between the bearing disks, in which groove channel the at least one polymer sliding element and the section of the second bearing element onto which the polymer sliding element has previously been slipped is arranged. The method according to the invention makes it particularly easy to produce an axial-radial plain bearing.In a preferred embodiment, before the second bearing disc is fixed to the first bearing disc, a spacer ring is arranged between the bearing discs, the thickness of which determines the axial length of the groove channel in which the at least one polymer sliding element and the section of the second bearing element onto which it is mounted are arranged. Preferably, in the method according to the invention, the thickness of the spacer ring is specifically selected to adjust the axial play between the bearing elements.In one embodiment, various axial-radial plain bearings are produced using the method according to the invention, wherein a first pair of different axial-radial plain bearings has the same bearing disks but a different spacer ring, the spacer rings differing in their thickness, and / or wherein a second pair of different axial-radial plain bearings each have an identically designed first bearing element, the different axial-radial plain bearings of the second pair differing either in the design of their at least one polymer sliding element or in the design of the second bearing element, the different polymer sliding elements in particular differing in their thickness, i.e. axial extension length, and / or the different second bearing elements differing in their radial extension length.

[0040] The invention further relates to a set consisting of various axial-radial plain bearings, which can differ from one another as explained here.

[0041] The invention is explained below with reference to and with reference to an embodiment shown in the accompanying drawings.

[0042] It shows :

[0043] Fig . 1 : a perspective view of the axial-radial

[0044] plain bearing according to the invention;

[0045] Fig. 2 : a sectional view along a central

[0046] Cross section through the axial-radial plain bearing according to the invention; Fig. 3: a perspective view of parts of the axial-

[0047] Radial plain bearing according to the invention;

[0048] Fig. 4 : a perspective view of a polymer

[0049] Guide element of the axial-radial plain bearing according to the invention; and

[0050] Fig . 5 : another perspective view of parts of the

[0051] Axial-radial plain bearing according to the invention.

[0052] 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.

[0053] 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.

[0054] The first bearing element 20 is made up of several parts and comprises a first and a second bearing disk 21, 22 which are connected to one another in a rotationally fixed manner by means of fastening means (not shown), for example by means of threaded bolts, with the interposition of a spacer ring 40. The bearing disks 21, 22 are designed as essentially flat disks, i.e. their thickness is significantly smaller than their width. The bearing disks 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, the bolt circles 50 of the first and second bearing disks corresponding to one another.

[0055] 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 context of the present invention, the thickness refers to the axial dimension, and the width refers to the radial extent.

[0056] The thickness of the spacer ring 40 determines the clear width of the groove 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 supported. The first and second bearing discs 21, 22 each form head plates of the axial-radial plain bearing 10, which is designed as a polymer rotary table bearing.

[0057] 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.

[0058] Figure 3 shows a perspective view of the axial-radial plain bearing according to the invention, in which, for the sake of clarity, the second bearing disk 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. The polymer sliding elements 70 have a configuration as shown in the perspective view according to Figure 4. They are designed as U-profile segments with two legs 71 which are connected to one another via a profile web 72. These are, as can be seen in particular from the illustration in Figure 3, not connected to one another and are inserted into the groove channel 11 and form a radially outwardly open sliding channel 73 into which, as shown in Figure 5, the second bearing element 30 is inserted.

[0059] Figure 5 shows a perspective view of the axial-radial plain bearing 10 according to the invention, which corresponds to the view in Figure 3, wherein the second bearing disc 22 and some of the polymer sliding elements 70 are not shown for reasons of simplification.

[0060] The legs 71 of the polymer sliding elements 70 each encompass axial surfaces 31 of the second bearing element 30. The profile web 72 of the polymer sliding elements 70 rests in the installed position 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

[0061] Form axial bearing surfaces.

[0062] List of reference symbols

[0063] Axial-radial plain bearing groove channel

[0064] Bearing axis first bearing element first bearing disc second bearing disc second bearing element axial surface spacer ring

[0065] Radial bearing surface first bolt circle

[0066] Mounting holes second bolt circle mounting holes polymer sliding elements leg

[0067] Profile webs Axial bearing surfaces

Claims

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 the radial and axial decoupling of the bearing elements (20, 30), wherein at least the first bearing element (20) is designed 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 have at least one spacer ring (40) or at least one Include spacer ring segment,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).

2. Axial-radial plain bearing (10) according to claim 1, characterized in that the spacer ring (40) is rotationally connected to at least one, preferably two bearing discs (21, 22).

3. Axial-radial plain bearing (10) according to one of the preceding claims, characterized in 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 bolt circle (50).

4. Axial-radial plain bearing (10) according to one of the preceding claims, characterized in that 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), 5. Axial-radial plain bearing (10) according to one of the preceding claims, characterized in that a radial bearing surface of the at least one polymer sliding element (70) decouples the second bearing element (30) from the spacer ring (40) and two axial bearing surfaces of the polymer sliding element (70) decouple the second bearing element (30) from the first bearing element (20), in particular from the bearing disks (20, 21).

6. Axial-radial plain bearing (10) according to one of the preceding Claims comprising a plurality of polymer sliding elements (70) which are arranged distributed over the circumference of the bearing axis (12).

7. Axial-radial plain bearing (10) according to claim 6, characterized in that the polymer sliding elements (70) form partial circle segments of the sliding channel (73) encircling the bearing axis (12).

8. Axial-radial plain bearing (10) according to one of the preceding claims, characterized in that the polymer sliding elements (70) are at least partially formed from a tribopolymer.

9. Axial-radial plain bearing (10) according to one of the preceding claims, characterized in that the polymer sliding elements (70) form partial circle segments.

10. Axial-radial plain bearing (10) according to one of the preceding claims, characterized by a single one-piece spacer ring (40) whose thickness 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.

11. Axial-radial plain bearing (10) according to one of the preceding claims, characterized in that the thickness of the spacer ring (40) determines an axial bearing clearance.

12. Axial-radial plain bearing (10) according to one of the preceding claims, characterized in that 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 mounting holes for attaching a connecting component.

13. A method for producing 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, wherein the second bearing element (30) is designed in the manner of a ring which has a central ring recess, characterized in thatthat the at least one polymer sliding element (70) is placed from the ring recess onto the second bearing element and then the second bearing element (30) is placed onto a first bearing disc (21) of the first bearing element (20) and then a second bearing disc (22) of the first bearing element (20) is fixed to the first bearing disc (21), whereby a groove channel (11) is formed between the bearing discs (21, 22), in which the at least one polymer sliding element (70) is arranged, wherein in particular before the second bearing disc (22) is fixed to the first bearing disc (21), a spacer ring (40) is arranged between the bearing discs (21, 22), the thickness of which spacer ring determines an axial length of the groove channel (11).

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