Retainer and turntable bearing

Abstract

The invention relates to a cage (1) for a rotary table bearing (2) for accommodating a plurality of rolling bodies (3) guided in the cage (1), the cage (1) being formed from a plurality of ring-segment cage segments (4a, 4b), each of which has a plurality of cage pockets (5) for accommodating the rolling bodies (3), the cage segments (4a, 4b) rest against each other at the circumferential end faces (6a, 6b, 6c, 6d) thereof when the cage segments (4a, 4b) are mounted in the turntable bearing (2), at least one of the end faces (6a, 6b, 6c, 6d) having a projection (7) projecting from the respective end face (6a, 6b, 6c, 6d) in the circumferential direction, and at least one of the end faces (6a, 6b, 6c, 6d) having a projection (7) projecting from the respective end face (6a, 6b, 6c, 6d) in the circumferential direction. In the mounted state of the cage (1), the protrusions are at least temporarily in contact with the end faces (6a, 6b, 6c, 6d) of the cage segments (4a, 4b) adjacent in the circumferential direction.

Description

Technical Field

[0001] The invention relates to a cage for a swivel bearing, which is used to accommodate a plurality of rolling elements guided in the cage. Among them, the cage is composed of a plurality of ring-segment cage segments, and each cage segment has a plurality of cage pockets for accommodating the rolling elements. Among them, in the state where the cage segments are installed in the swivel bearing, they abut against each other at their circumferential end faces. Background Art

[0002] Machine tools for material removal by means of machining usually are equipped with a swivel table supported in a rotatable manner about a vertical axis, and one or more workpieces to be machined are clamped on this swivel table. This swivel table is rotatably supported relative to the processing machine by means of a swivel bearing and is coupled to a drive. Known swivel bearings or swivel configurations for supporting such swivel tables, which can rotate about a vertical axis for example, usually are provided with multiple rows of thrust radial bearings. Such a configuration is known from WO 2013 / 034341 A1, in which one row of cylindrical rollers forms a radial row, and two rows of cylindrical rollers form the axial rows of the swivel bearing. The three rows of cylindrical rollers of this swivel bearing roll on the raceways provided by two bearing rings.

[0003] Another angular contact rolling bearing is known from DE 36 20 102 A1. As Figure 1 and the related description show, this bearing consists of an inner ring and an outer ring concentrically arranged with this inner ring, and cylindrical rolling elements for absorbing radial forces roll between this inner ring and this outer ring. Cylindrical rolling elements for absorbing axial forces are arranged on both sides of the outer ring, and their raceways are defined on the one hand by the end faces of the outer ring and on the other hand by two raceway washers also arranged on both sides. This bearing is fixed together by means of fastening screws passing through the inner ring and the two raceway washers. As especially Figure 2 、 3 and shown in 4, the cylindrical rolling elements of the two thrust bearings are guided in some way by cage segments such that each cylindrical rolling element is accommodated by a single cage segment. This single cage segment is provided with two circumferentially spaced-apart projections at its radially inner end, which engage into the gap formed by the inner ring and the outer ring. The longitudinal sides of the pockets of the respective cage segments are rounded. In addition, these cage segments also have slits in order to prevent the cylindrical rollers of the thrust bearing from being staggered in the axial direction, such that the longitudinal sides of these pockets are bent to a certain extent due to the existing slits. Summary of the Invention

[0004] The object of the invention is to provide an improved cage for a swivel bearing, which can achieve a higher rotational speed of the swivel bearing compared to the cages known from the prior art. The object of the invention also lies in realizing a correspondingly optimized swivel bearing.

[0005] The above object is achieved by a cage for a swivel bearing, the cage being adapted to accommodate a plurality of rolling elements guided in the cage, wherein the cage is composed of a plurality of ring-segment-shaped cage segments, each of the cage segments having a plurality of cage pockets for accommodating the rolling elements, wherein, in the state where the cage segments are installed in the swivel bearing, they abut against each other at their circumferential end faces, wherein at least one of the end faces has a raised portion protruding from the respective end face in the circumferential direction, and the raised portion contacts at least temporarily the end face of the cage segment adjacent in the circumferential direction in the installed state of the cage.

[0006] The advantage of this is that the friction between the cage segments occurring during the operation of the swivel bearing can be reduced by this raised portion, and thus the wear at the end-side contact surfaces of the cage segments adjacent in the circumferential direction can be reduced. Due to the reduced friction, the heat generation based on friction is reduced, and thus a higher rotational speed of the swivel bearing can be achieved. By the radius of the raised portion, when the respective cage segments are joined together, straight, flat, and curved surfaces always meet each other in a particularly preferred manner on the circumferentially adjacent end faces of the cage segments. Thereby, the generated contact surface is reduced to a line contact and a better lubricant supply in the intermediate gap generated by the raised portion is ensured.

[0007] The term "raised portion" in the present application refers to the surface shape of the end face of the cage segment, and this surface shape is not planar or flat, but is circular or outwardly curved towards the outside. In the present application, the ring-segment-shaped cage segment defines a geometric object having an inner circle radius and an outer circle radius, and an angle is formed in the circumferential direction between the two ends of this geometric object.

[0008] First, the individual elements of the claimed invention subject matter are set forth in the order in which they are presented in the claims, and particularly preferred embodiments of the invention subject matter will be described hereinafter.

[0009] The cage is in particular provided and designed for a swivel bearing, for example for a machine tool.

[0010] The swivel bearing may have an inner ring. The inner ring of the swivel bearing may be composed of metal and / or ceramic material. In principle, it is conceivable that the inner ring is integrally formed or composed of multiple parts, particularly composed of two parts. The inner ring may have an inner ring groove. In the inner ring groove, in particular, a cover plate, a sealing washer, and / or a seal may be arranged in a force-fitting and / or form-fitting manner. The inner ring groove is preferably constructed as a circumferential groove in the inner ring.

[0011] The turntable bearing may further include an outer ring. The outer ring of the turntable bearing may be made of metal and / or ceramic materials. In principle, it is conceivable that the outer ring is integrally formed or composed of multiple parts, especially two parts. The outer ring may have an outer ring groove. In the outer ring groove, a cover plate, a sealing washer and / or a seal may be arranged, especially in a force-fitting and / or form-fitting manner. The outer ring groove is preferably constructed as a circumferential groove in the outer ring.

[0012] The turntable bearing preferably has a plurality of rolling elements. Depending on the type of rolling bearing structure, the rolling elements have the shape of balls or rollers. Roller-shaped rolling elements are also referred to as roller rolling elements, while ball-shaped rolling elements are called bearing balls. Roller-shaped rolling elements can be selected, for example, from symmetrical spherical roller bearings, asymmetrical spherical roller bearings, cylindrical rollers, needle rollers and / or tapered rollers.

[0013] The rolling elements can roll within the turntable bearing, especially on the inner raceway of the inner ring. For this purpose, the surface of the inner raceway can advantageously be constructed in a correspondingly wear-resistant manner, for example, also by means of corresponding surface treatment methods and / or by applying corresponding additional material layers. The inner raceway can be constructed in a flat or profiled manner. The profiled design of the inner raceway can be used, for example, to guide the rolling elements on the inner raceway. The flat forming of the inner raceway can, for example, allow a certain axial displaceability of the rolling elements on the inner raceway.

[0014] The rolling elements can roll within the turntable bearing, especially on the outer raceway of the outer ring. For this purpose, the surface of the outer raceway can advantageously be constructed in a correspondingly wear-resistant manner, for example, also by means of corresponding surface treatment methods and / or by applying corresponding additional material layers. The outer raceway can be constructed in a flat or profiled manner. The profiled design of the outer raceway can be used, for example, to guide the rolling elements on the outer raceway. The flat forming of the outer raceway can, for example, allow a certain axial displaceability of the rolling elements on the outer raceway.

[0015] The rolling elements are guided within a cage and spaced apart from each other. The cage is preferably made of plastic. In addition, the cage preferably accommodates the rolling elements in a loss-preventing manner. The cage is especially constructed such that the rolling elements are spaced apart from each other, so as to keep, for example, the friction and heat generation of the rolling elements as low as possible. In addition, the cage keeps the rolling elements in a fixed state and in contact with each other during rolling, so that a uniform load distribution can be achieved. The cage is implemented in a multi-part manner.

[0016] The swivel bearing can also have a seal to prevent the lubricant from escaping from the swivel bearing or to prevent dirt or moisture from entering the swivel bearing. For this purpose, the seals used can be provided with one or more sealing lips that can bear against the components of the swivel bearing. These seals are designed such that, on the one hand, they seal the bearing as well as possible over the entire service life, and on the other hand, the friction caused by the bearing seals is not too high.

[0017] According to an advantageous design of the invention, it can be provided that the end face with a bulge protruding in the circumferential direction from the respective end face is at least temporarily in contact with the substantially flat end face of the cage segment adjacent in the circumferential direction in the installed state of the cage. The advantage of this design is that a particularly advantageous line contact can thereby be formed between the circumferentially adjacent cage segments.

[0018] According to another preferred refinement of the invention, it can also be provided that bulges protruding in the circumferential direction from the respective end face are formed on both end faces of the cage segment. This can further improve the circumferential contact of adjacent cage segments.

[0019] Furthermore, according to an equally advantageous design of the invention, it can be provided that the cage segments are constructed substantially as standard parts, which can thus have a positive effect on the manufacturing costs.

[0020] According to another particularly preferred embodiment of the invention, it can be provided that the bulge extends over the entire end face of the cage segment, which can in particular have a particularly positive effect on the wear susceptibility and structural stability of the respective end face.

[0021] Furthermore, the invention can be further improved in such a way that the cage segments are made of plastic, in particular of polyamide, and particularly preferably of fiber-reinforced polyamide. The advantage of this design is that the cage segments can thereby be produced in a cost-effective manner and have a relatively low self-weight.

[0022] In a likewise preferred design variant of the invention, it can also be provided that the cage pockets are arranged in a single row or in multiple rows, wherein a multiple-row layout can generally provide a greater axial load-carrying capacity.

[0023] The invention can also be further improved advantageously in the following manner: The cage segment has a radially inner side surface, and the radially inner side surface has a corrugated surface profile. The corrugated surface profile is designed such that during the operation of the rotary table bearing, a hydrodynamic lubricating film structure of lubricating oil is established between the inner side surface and a substantially flat cylindrical structure that is radially opposite to the inner side surface. In this way, direct frictional contact between the members rotating relative to each other can be avoided or at least reduced. Specifically, the lubricating film constructed during operation separates the inner side surface from the cylindrical structure, such that the inner side surface does not come into direct contact with the cylindrical structure. In this case, the corrugated shape of the inner side surface causes this hydrodynamic lubricating film structure and in principle avoids large-area frictional contact.

[0024] According to another preferred design of the subject matter of the invention, it can be set that when the pitch circle diameter of the cage is 600 - 800 mm, the radius of the raised portion is between 30 - 70 mm, which has been proven to be particularly advantageous for reducing friction and high rotational speeds.

[0025] The object of the invention is also achieved by a rotary table bearing, which includes a cage having rolling elements guided therein, wherein the cage is constructed according to any one of claims 1 to 9. Description of the Drawings

[0026] The present invention will be described in detail below in conjunction with the drawings without limiting the general inventive concept.

[0027] Wherein:

[0028] Figure 1 Partial sectional perspective view of the rotary table bearing,

[0029] Figure 2 Top view of two circumferentially adjacent cage segments of the cage,

[0030] Figure 3 Detailed top view of the circumferential contact points of the cage segment,

[0031] Figure 4 Detailed perspective view of the cage segment. Detailed Description of the Preferred Embodiment

[0032] Figure 1 The rotary table bearing 2 of the applicant is shown, which is also called a thrust radial bearing, and the type names are YRT and YRTC. These bearings are generally known from the prior art. For its overall design and working principle, refer to the relevant publications of the applicant.

[0033] The cage 1 will be described in detail below, which can be used in combination with Figure 1 the shown rotary table bearing 2. From Figure 1As can be seen, such a bearing may have cages 1a, 1b for guiding rolling elements 3a, 3b subjected to axial forces and a cage 1c for guiding rolling elements 3c subjected to radial forces. The cage 1 described hereinafter is particularly arranged to accommodate rolling elements 3a, 3b subjected to axial forces.

[0034] From Figure 2 As can be clearly seen, the cage 1 is composed of a plurality of ring-segment cages 4a, 4b which are arranged successively in the circumferential direction to form a circumferentially closed annular cage 1. A plurality of cage pockets 5 for accommodating rolling elements 3 are respectively formed in the cage segments 4a, 4b. Among them, in the state where the cage segments 4a, 4b are installed in the turntable bearing 2, they are respectively in contact with each other at their circumferentially adjacent end faces 6a, 6b, 6c, 6d.

[0035] In this case, one of these end faces 6a, 6c has a raised portion 7 protruding in the circumferential direction from the corresponding end face 6a, 6c. This raised portion is at least temporarily in contact with the end faces 6b, 6d of the circumferentially adjacent cage segments 4a, 4b in the installed state of the cage 1.

[0036] From Figure 3 As can be seen, in the illustrated embodiment of the cage 1, the end faces 6a, 6c having the raised portions 7 protruding in the circumferential direction from the corresponding end faces 6a, 6c are at least temporarily in contact with the substantially flat end faces 6b, 6d of the circumferentially adjacent cage segments 4a, 4b in the installed state of the cage 1. Figure 3 It is also shown that the raised portion 7 extends over the entire end face 6a of the cage segment 4a. Thus, a line contact is formed between the raised portion 7 and the circumferentially adjacent end face 6b, and the frictional contact between the cage segments 4a, 4b can be reduced by means of this line contact.

[0037] In this case, the cage segments 4a, 4b are basically constructed in a general-purpose manner and are made of plastic, particularly made of polyamide, and particularly preferably made of fiber-reinforced polyamide.

[0038] In Figure 3 the cage segment 4a is constructed such that the cage pockets 5 are arranged in a single row. Of course, the cage pockets 5 can also be arranged in multiple rows, although this is not shown in Figure 3 this case.

[0039] Figure 4 In particular, it is shown that the cage segments 4a, 4b have a radially inner side 9 which has a wavy surface profile. This wavy surface profile is designed such that during the operation of the turntable bearing 2, a hydrodynamic lubricating film structure of lubricating oil is established between the inner side 9 and a substantially flat cylindrical structure radially opposite to this inner side 9.

[0040] This can avoid or at least reduce the direct frictional contact between the members rotating relative to each other. Specifically, a lubricating film formed during operation separates the inner side surface from the cylindrical structure, such that the inner side surface does not come into direct contact with the cylindrical structure. In this case, the wavy shape of the inner side surface causes the formation of this hydrodynamic lubricating film and, in principle, avoids large-area frictional contact.

[0041] The present invention is not limited to the embodiments shown in the drawings. Therefore, the above description should not be construed as restrictive but rather as illustrative. The following claims should be understood to mean that the claimed features exist in at least one embodiment of the present invention. This does not exclude the existence of other features. If the claims and the above description define a "first" feature and a "second" feature, such designations are used to distinguish between two features of the same type and do not specify a priority order.

[0042] List of Reference Numerals

[0043] 1 Cage

[0044] 2 Turntable Bearing

[0045] 3 Rolling Element

[0046] 4 Cage Segment

[0047] 5 Cage Pocket

[0048] 6 End Face

[0049] 7 Protrusion

[0050] 9 Side Face

Claims

1. A cage (1) for a slewing bearing (2), the cage being used to accommodate a plurality of rolling elements (3) guided in the cage (1), wherein, The cage (1) is composed of a plurality of ring-segment type cage segments (4a, 4b), and the cage segments respectively have a plurality of cage pockets (5) for accommodating the rolling elements (3). Among them, in the state where the cage segments (4a, 4b) are installed in the slewing bearing (2), they are in contact with each other at their circumferential end faces (6a, 6b, 6c, 6d). It is characterized in that At least one of the end faces (6a, 6b, 6c, 6d) has a raised portion (7) protruding from the corresponding end face (6a, 6b, 6c, 6d) in the circumferential direction, and the raised portion is at least temporarily in contact with the end faces (6a, 6b, 6c, 6d) of the cage segments (4a, 4b) adjacent in the circumferential direction in the installed state of the cage (1).

2. The cage (1) according to claim 1, It is characterized in that The end face (6a, 6b, 6c, 6d) having the raised portion (7) protruding from the corresponding end face (6a, 6b, 6c, 6d) in the circumferential direction is at least temporarily in contact with the substantially flat end faces (6a, 6b, 6c, 6d) of the cage segments (4a, 4b) adjacent in the circumferential direction in the installed state of the cage (1).

3. The cage (1) according to claim 1 or 2, It is characterized in that Raised portions (7) protruding from the corresponding end faces (6a, 6b, 6c, 6d) in the circumferential direction are respectively constructed on two end faces (6a, 6b, 6c, 6d) of the cage segments (4a, 4b).

4. The cage (1) according to any one of the above claims, It is characterized in that The cage segments (4a, 4b) are constructed in a substantially universal part manner.

5. The cage (1) according to any one of the above claims, It is characterized in that The raised portion (7) extends over the entire end face (6a, 6b, 6c, 6d) of the cage segment (4a, 4b).

6. The cage (1) according to any one of the above claims, It is characterized in that The cage segments (4a, 4b) are made of plastic, especially made of polyamide, and particularly preferably made of fiber-reinforced polyamide.

7. The cage (1) according to any one of the above claims, It is characterized in that The cage pockets (5) are arranged in a single row or multiple rows.

8. The cage (1) according to any one of the above claims, It is characterized in that The cage segments (4a, 4b) have a radially inner side surface (9), and the radially inner side surface has a corrugated surface profile, and the corrugated surface profile is designed such that during the operation of the slewing bearing (2), a hydrodynamic lubricating film structure of lubricating oil is established between the inner side surface (9) and a substantially flat cylindrical structure radially opposite to the inner side surface (9).

9. The cage (1) according to any one of the above claims, It is characterized in that When the pitch diameter of the cage (1) is 600 - 800 mm, the radius of the raised portion (7) is between 30 - 70 mm.

10. A turntable bearing (2), which comprises a cage (1) having rolling elements (3) guided therein, wherein, The cage (1) is constructed according to any one of claims 1 to 9.

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