ROLLING BEARING ASSEMBLY AND METHOD FOR PRODUCING A POCKET CAGE

Description

Field of the invention

[0001] The invention relates to a rolling bearing arrangement comprising a rolling bearing with an inner ring, an outer ring, rolling elements and a cage, wherein the inner ring has an inner ring raceway and the outer ring has an outer ring raceway, wherein the rolling elements are arranged rotatably between the inner ring and the outer ring in the cage at a distance from one another, wherein the rolling elements roll on the inner ring raceway and the outer ring raceway, wherein the rolling elements are designed as rolling element rollers and the cage is designed as a pocket cage having two coaxially arranged pocket cage rings which are connected to a plurality of pocket cage axial separating webs to form pocket openings for receiving the rolling elements. The invention further relates to a method for producing a pocket cage. Background of the invention

[0002] Rolling bearings with cage-guided rolling elements are well known in the art. Examples of such cages include JP H05 118337 A, JP 2000 352 423 A, DE 16 94 407 U, or DE 696 27 937 T2. They can be used, in particular, to enable rotary movements with the lowest possible friction losses. Rolling bearings can be used, in particular, to fix and / or support axles and shafts. Depending on their design, they absorb radial and / or axial forces while simultaneously enabling the rotation of the shaft or the components mounted on an axle.

[0003] For this purpose, rolling elements are arranged between an inner and outer ring of the rolling bearing. Between these three main components—inner ring, outer ring, and the rolling elements—the friction within the rolling bearing is generally primarily rolling friction. Since the rolling elements in the inner and outer rings can roll preferentially on hardened steel surfaces with optimized lubrication, the rolling friction of such bearings is relatively low.

[0004] DE 10 2007 046131 B3, which is considered to be the closest, discloses a method for producing a pocket cage for a rolling bearing, comprising the steps of providing a cylinder sleeve with an inner circumferential surface, placing the cylinder sleeve on a shaft so that the inner circumferential surface bears against the shaft, and punching out pocket openings from the cylinder sleeve so that a pocket cage is formed.

[0005] There is a continuing need to be able to produce rolling bearings cost-effectively and in large batch sizes. Object of the invention

[0006] Thus, the object of the invention is to provide a rolling bearing having a cage with a manufacturing-optimized design, in particular, one that is optimized for a stamping process. Furthermore, the object of the invention is to provide an optimized method for producing a cage for a rolling bearing. Description of the invention

[0007] This object is achieved by a rolling bearing arrangement having the features listed in claim 3.

[0008] The advantage of this design lies in the fact that this design of the pocket cage axial separators is particularly suitable for manufacturing the pocket cage in high-speed punching processes, where high shear forces can occur when punching out the pocket openings. This can lead to undesirable plastic deformation of the pocket cage axial separators in designs that deviate from the one proposed here. This is particularly critical for cage designs that have internal grooves on the pocket cage axial separators, which are present, for example, for guiding lubricant within the rolling bearing. With the design according to the invention, a cage can be provided that has the grooves necessary for guiding lubricant between the rolling element and the cage and can, at the same time, be manufactured particularly economically and reliably.

[0009] First, the individual elements of the claimed subject matter of the invention are explained in the order in which they appear in the set of claims, and subsequently, particularly preferred embodiments of the subject matter of the invention are described.

[0010] A rolling bearing can be single-row or multi-row.

[0011] The inner ring can, in particular, connect the shaft accommodating the rolling bearing to the rolling bearing or the rolling elements. In particular, the outer surface of the shaft can be connected to the inner surface of the inner ring, with the rolling elements of the rolling bearing rolling on the inner ring raceway opposite this surface. The inner ring can be made of a metallic and / or ceramic material. It is generally conceivable for the inner ring to be constructed in one or more parts, particularly in two parts.

[0012] The outer ring can, in particular, connect the bearing support surrounding the rolling bearing to the rolling bearing or the rolling elements. In particular, the side of the bearing support facing the rolling bearing can be connected to the outer surface of the outer ring, with the rolling elements of the rolling bearing rolling on the outer ring raceway opposite this surface. The outer ring can be made of a metallic and / or ceramic material. It is generally conceivable for the outer ring to be constructed in one or more parts, particularly in two parts.

[0013] Depending on the bearing design, the rolling elements are shaped like a roller. They roll along the raceways of the bearing and are responsible for transferring the force acting on a radial rolling bearing from the outer ring to the inner ring and vice versa. Roller-shaped rolling elements are also referred to as roller rolling elements, and spherical rolling elements are referred to as bearing balls. Roller-shaped rolling elements can be selected, for example, from the group of symmetrical spherical rollers, asymmetrical spherical rollers, cylindrical rollers, needle rollers, and / or tapered rollers.

[0014] In connection with the invention, it is particularly preferred that the rolling elements are designed as needle rollers.

[0015] A rolling bearing assembly according to the invention has a cage designed as a pocket cage that guides the rolling elements. The cage is designed to space the rolling element rollers apart from one another, for example, to minimize friction and heat generation of the rolling elements. Furthermore, the cage keeps the roller rolling elements at a fixed distance from one another during rolling, thereby achieving an even load distribution.

[0016] The cage can preferably be made in one piece, but can also be made in several pieces.

[0017] The rolling elements can roll within the rolling bearing, particularly on the inner raceway of the inner ring. For this purpose, the surface of the inner raceway can advantageously be designed to be abrasion-resistant, for example, by means of an appropriate surface treatment process and / or by applying an appropriate additional material layer.

[0018] The inner ring raceway can be flat or profiled. A profiled design of the inner ring raceway can, for example, serve to guide the rolling elements on the inner ring raceway. A flat design of the inner ring raceway, on the other hand, can, for example, allow a certain degree of axial displacement of the rolling elements on the inner ring raceway.

[0019] The rolling elements can roll within the rolling bearing, particularly on the outer raceway of the outer ring. For this purpose, the surface of the outer ring raceway can advantageously be designed to be abrasion-resistant, for example, by means of an appropriate surface treatment process and / or by applying an appropriate additional material layer.

[0020] The outer ring raceway can be flat or profiled. A profiled outer ring raceway can, for example, serve to guide the rolling elements on the outer ring raceway. A flat outer ring raceway, on the other hand, can allow a certain degree of axial displacement of the rolling elements on the outer ring raceway.

[0021] According to a preferred embodiment of the invention, it may be advantageous for the central contact surface to be arranged centrally on the pocket cage axial separators relative to their axial extent, so that shear forces acting on the pocket cage axial separators during production are distributed as evenly as possible in the axial extent across the pocket cage axial separators. Furthermore, the central arrangement provides a support point in the pocket cage axial separators where the greatest bending stresses can typically occur in the pocket cage axial separators during punching of the pocket openings.

[0022] It may further be advantageous for the grooves to each have an opening width of between 2% and 15% of the axial extent of the pocket cage axial separating webs, so that a sufficiently large support and contact surface can be provided when punching out the pocket openings during the manufacturing process of the cage.

[0023] In a further development of the invention, it may further be preferred that the grooves have an identical opening width, which has proven to be advantageous with regard to a symmetrical stress distribution in the pocket cage axial separating webs during the manufacturing process.

[0024] Furthermore, it can be advantageous for the grooves to have different axial cross-sectional contours, allowing the lubricant fill volume to be individually adjusted for each groove. However, it is also possible, and advantageous from a manufacturing perspective, for the grooves to have identical axial cross-sectional contours.

[0025] According to a further advantageous embodiment of the invention, it may be preferred that the axial section contour of at least one of the grooves, preferably all grooves, has a circular shape.

[0026] According to a preferred embodiment of the invention, it may be advantageous for the axial section contour of at least one of the grooves, preferably all of the grooves, to have a circular arc section, an extension section adjoining the circular arc section and running plane-parallel to the contact surface, and a ramp section adjoining the extension section. This allows for a comparatively large filling volume in the grooves for a lubricant and, at the same time, a sufficiently high level of protection against undesirable plastic deformations on the pocket cage axial separating webs during the manufacturing process.

[0027] In this context, it has proven particularly advantageous that the ramp sections of two axially adjacent grooves are aligned towards each other.

[0028] Furthermore, it is particularly preferred that the radial extent of the pocket cage axial separating webs be identical. In this context, it is also highly preferred that the pocket cage rings have a radial extent that corresponds to the radial extent of the pocket cage axial separating webs.

[0029] The object of the invention is achieved by a method for producing a pocket cage for a rolling bearing, comprising the steps listed in claim 1.

[0030] In this context, it may be advantageous for the shaft to have at least four punching pockets distributed over its circumference, into which a punching tool can engage to form a cage pocket, thereby enabling a particularly short production time for the pocket cage. Short description of the drawings

[0031] A preferred embodiment of the invention is explained in more detail below with reference to the accompanying drawings, without limiting the general inventive concept. In the drawings: Figure 1 shows a rolling bearing in an axial sectional view, Figure 2 shows a pocket cage in a perspective view, Figure 3 shows a first embodiment of a pocket cage axial separating web of the pocket cage in an axial sectional view, Figure 4 shows a second embodiment of a pocket cage axial separating web of the pocket cage in an axial sectional view, Figure 5 shows a cylinder sleeve in a perspective view, Figure 6 shows the introduction of grooves on the inner surface of the cylinder sleeve in a schematic view, Figure 7 shows a cylinder sleeve with internal grooves in a perspective view, Figure 8 shows the introduction of the pocket openings in the cylinder sleeve by means of a punching process in a perspective view, and Figure 9 shows a flow diagram of a method for producing a pocket cage. Detailed description of the drawings

[0032] The drawings are merely schematic in nature and serve exclusively to facilitate understanding of the invention. Like elements are provided with the same reference numerals. Furthermore, the different features of the various embodiments can be freely combined with one another within the bounds of technical feasibility.

[0033] Figure 1 shows a rolling bearing arrangement 1, comprising a rolling bearing 2 with an inner ring 3, an outer ring 4, rolling elements 5 and a cage Figure 6 . The inner ring 3 has an inner ring raceway 7 and the outer ring 4 has an outer ring raceway 8, wherein the rolling elements 5 are rotatably mounted in the cage between the inner ring 3 and the outer ring 4. Figure 6 are arranged at a distance from one another. The rolling elements 5 roll on the inner ring raceway 7 and the outer ring raceway 8 and, in the embodiment shown, are designed as rolling element rollers 9.

[0034] Accordingly, the Kä Figure 6configured as a pocket cage 10 formed from a metallic material, which in the Figure 2 is shown. The pocket cage 10 has two coaxially arranged identical pocket cage rings 11, which are connected to a plurality of pocket cage axial separators 12 to form pocket openings 13 for receiving the rolling elements 5. The pocket cage rings 11 and the pocket cage axial separators 12 are formed monolithically with one another.

[0035] A first embodiment of the pocket cage axial separators 12 is shown in Figure 3shown and is explained in more detail below. The pocket cage axial separators 12 have, on the radially inward-facing side, a substantially flat contact surface 14, each with two grooves 15 running in the circumferential direction of the pocket cage 10. The central contact surface 16, which is formed between the two grooves 15, has an axial extent that corresponds to 3% to 40% of the axial extent of one of the pocket cage axial separators 12. Between the pocket cage axial separators 12 and the pocket cage rings 11, a waist 31 is formed on each of the pocket cage axial separators 12 on both sides of the pocket cage axial separators 12 in order to not only guide lubricant through the waist 31 but also, in particular, to bring about a spring-elastic effect and / or tension guidance in the pocket cage axial separators 12.

[0036] The central contact surface 16 is arranged centrally on the pocket cage axial separating webs 12 with respect to the axial extent of the latter. This is shown in the Figure 2 by the central axis of the pocket cage axial separator 12, indicated by a dash-dot line. The mirror-symmetrical design of the pocket cage axial separator 12 along this central axis is clearly visible.

[0037] The grooves 15 also have identical opening widths 17 between 2% and 15% of the axial extent of the pocket cage axial separating webs 12. The axial section contour 18 of each of the grooves 15 has a circular shape in the embodiment shown.

[0038] Figure 4 shows one of the Figure 3 different design of the axial section contours 18 of the grooves 15. The axial section contour 18 of the grooves 15 according to the embodiment of the Figure 3has a circular arc section 19, an extension section 20 adjoining the circular arc section 19 and running plane-parallel to the contact surface 14, and a ramp section 21 adjoining the extension section 20. The ramp sections 21 of two axially adjacent grooves 15 are aligned toward each other. Here, too, the grooves 15 have identical opening widths 17 between 2-15% of the axial extension of the pocket cage axial separating webs 12.

[0039] A method 22 for producing a pocket cage 10 for a rolling bearing 2 is described with reference to Figures 5 to 9 explained in more detail: In a first process step a) a metallic cylinder sleeve 23 with an inner surface 24 is provided, as shown in the Figure 5It can be seen that the inner surface 24 of the semi-finished product is the later radially inner contact surface 14 of the pocket cage 10. The wall thickness of the cylindrical sleeve 23 corresponds to the later radial extent of the pocket cage axial separators 12 and the pocket cage rings 11.

[0040] Subsequently, in a process step b) two grooves 15 are introduced into the inner surface 24 of the cylinder sleeve 23, which is shown in the Figure 6 is shown. The grooves 15 are formed by means of a grooving tool 30, which is pressed radially from the inside outward against the inner circumferential surface 24. By rolling the grooving tool 30 against the inner circumferential surface of the cylinder sleeve 23, the grooves 15 can then be formed, in particular without cutting. The shaping geometries of the grooving tool 30 have an outer contour that corresponds to the later axial section contour 18 of the grooves 15.

[0041] The cylinder sleeve 23 prepared in this way is then placed onto a shaft 25 in a process step c) so that the inner circumferential surface 24 rests against the shaft 25. Finally, in the process step designated d), the pocket openings 13 are punched out of the cylinder sleeve 23 so that a pocket cage 10 is formed, as shown in the Figures 2 to 4 is shown. The punching tool 28 lowers toward the shaft 25 and punches out a corresponding pocket opening 13 from the cylinder sleeve 10. The shaft 25 can be rotated via the shaft drive 26, wherein the shaft drive 26 preferably comprises a stepper motor. The shaft 25, which can also be referred to as a die, has at least four punching pockets distributed over its circumference, into which the punching tool 28 can engage to form a pocket opening 13.

[0042] The cylindrical sleeve 23 can enable punching on a punching machine, such as an XAV machine, in particular thanks to the central contact surface 16 of the pocket cage axial separators 12, which is designed as a support surface. Due to the two axially spaced grooves 15, the central contact surface 16 thus remains a support surface for supporting a pocket cage axial separator 12 during punching.

[0043] The invention is not limited to the embodiments illustrated in the figures. The above description is therefore not to be considered restrictive, but rather explanatory. The following claims are to be understood as meaning that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. Where the claims and the above description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a priority. List of reference symbols

[0044] 1Rolling bearing arrangement 2Rolling bearing 3Inner ring 4Outer ring 5Rolling element 6Cage 7Inner ring raceway 8Outer ring raceway 9Rolling element rollers 10Pocket cage 11Pocket cage rings 12Pocket cage axial separators 13Pocket openings 14Contact surface 15Grooves 16Central contact surface 17Opening width 18Axial section contour 19Circular arc section 20Extension section 21Ramp section 22Process 23Cylinder sleeve 24Inner surface 25Shaft 26Shaft drive 27(not shown) 28Punching tool 29Cutting plane 30Grooving tool 31Sidecut

Claims

1. A method (22) for producing a pocket cage (10) for a rolling bearing (2), having the following steps: a) providing a cylinder sleeve (23) having an inner lateral surface (24), b) introducing at least two grooves (15) into the inner lateral surface (24), c) placing the cylinder sleeve (23) on a shaft (25) so that the inner lateral surface (24) rests against the shaft (25), d) punching out pocket openings (13) from the cylinder sleeve (23) so that a pocket cage (10) is formed, wherein a central contact surface (16) formed between the two grooves (15) in order to support a pocket cage axial separating web (12) during punching has an axial extent which lies between 3% and 40% of the axial extent of one of the pocket cage axial separating webs (12).

2. The method according to claim 1, characterized in that the shaft (25) has at least four punching pockets distributed over its circumference, into which a punching tool (28) can engage for forming a pocket opening (13).

3. A rolling bearing arrangement (1), comprising a rolling bearing (2) having an inner ring (3), an outer ring (4), rolling elements (5) and a cage (6), wherein the cage (6) is produced by the method according to any one of the preceding claims, wherein the inner ring (3) has an inner ring raceway (7) and the outer ring (4) has an outer ring raceway (8), wherein the rolling elements (5) are arranged between the inner ring (3) and the outer ring (4) at a distance from one another in the cage (6) so that they can rotate, wherein the rolling elements (5) roll on the inner ring raceway (7) and the outer ring raceway (8), wherein the rolling elements (5) are designed as rolling element rollers (9) and the cage (6) is designed as a pocket cage (10) having two coaxially arranged pocket cage rings (11) which are connected to a plurality of pocket cage axial separating webs (12) forming pocket openings (13) for receiving the rolling elements (5), characterized in that the pocket cage axial separating webs (12) have, on the radially inward-facing side, a substantially flat contact surface (14) with at least two grooves (15) running in the circumferential direction of the pocket cage (10), wherein the central contact surface (16), which is formed between the two grooves (15), has an axial extent which corresponds to between 3% and 40% of the axial extent of one of the pocket cage axial separating webs (12).

4. The rolling bearing arrangement (1) according to claim 3, characterized in that the central contact surface (16) is arranged centrally on the pocket cage axial separating webs (12) with respect to the axial extent thereof.

5. The rolling bearing arrangement (1) according to any one of the preceding claims 3 or 4, characterized in that the grooves (15) each have an opening width (17) between 2% and 15% of the axial extent of the pocket cage axial separating webs (12).

6. The rolling bearing arrangement (1) according to any one of the preceding claims 3 to 5, characterized in that the grooves (15) have an identical opening width (17).

7. The rolling bearing arrangement (1) according to any one of the preceding claims 3 to 6, characterized in that the grooves (15) have differing axial cutting contours (18).

8. The rolling bearing arrangement (1) according to claim 7, characterized in that the axial cutting contour (18) of at least one of the grooves (15) has a circular shape.

9. The rolling bearing arrangement (1) according to claim 7, characterized in that the axial cutting contour (18) of at least one of the grooves (15) has a circular arc section (19), an extent section (20) adjoining the circular arc section (19) and extending plane-parallel to the contact surface (14), and a ramp section (21) adjoining the extent section (20).

10. The rolling bearing arrangement (1) according to claim 9, characterized in that the ramp sections (21) of two axially adjacent grooves (15) are aligned towards each other.