Bearing cage for a rolling bearing and method for producing such a bearing cage
The two-part bearing cage with positive locking elements addresses the issues of radial expansion and manufacturing costs by ensuring stable rolling element guidance and efficient production.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- AB SKF SKF PATENT DEPARTMENT
- Filing Date
- 2025-12-15
- Publication Date
- 2026-06-25
AI Technical Summary
Existing bearing cages for rolling bearings face issues such as radial bending and expansion at high speeds, leading to increased friction and jamming, and are often costly to manufacture due to processes like ultrasonic welding.
A two-part bearing cage design with axially extending connecting elements and complementary receptacles that form a positive lock when engaged, using heat or cold forming to create a secure connection between cage halves, eliminating the need for ultrasonic welding.
The design provides stable and secure hold of rolling elements at high speeds, preventing deformation and jamming, while being cost-effective to produce, with a homogeneous outer surface ensuring smooth lubricant flow and easy assembly.
Smart Images
Figure EP2025087181_25062026_PF_FP_ABST
Abstract
Description
[0001] 2024P00186DE
[0002] Bearing cage for a rolling bearing and manufacturing process of such a bearing cage
[0003] Technical field
[0004] The present invention relates to a two-part bearing cage for a rolling bearing according to the preamble of claim 1. Furthermore, the present invention relates to a rolling bearing according to claim 9. In addition, the present invention relates to a method for manufacturing a bearing cage according to claim 10.
[0005] Technical background
[0006] For various applications, such as ball bearings, a one-piece snap-in cage can be used. However, with previously used bearing cages, the elements used to hold the rolling elements can bend radially outwards at high speeds, causing the cage to expand and thus contact with the rings, resulting in increased friction or jamming of the rolling elements. The cage can also disengage.
[0007] Alternatively, two-part bearing cages can be used. These are currently joined using ultrasonic welding, which is very expensive.
[0008] It is therefore an object of the present invention to provide a bearing cage that is suitable for high speeds and can be manufactured cost-effectively and in a time-efficient manner.
[0009] Summary of the invention
[0010] This problem is solved by a bearing cage according to claim 1, by a rolling bearing according to claim 9, and by a method for manufacturing a bearing cage according to claim 10. 2024P00186DE
[0011] The following proposes a two-part bearing cage for a rolling bearing. The bearing cage consists of a first cage half and a second cage half, each with an annular base body. The bearing cage features axially extending connecting elements. The first cage half and / or the second cage half include complementary receptacles for the connecting elements. The connecting elements can engage in the receptacles of the first cage half and / or the second cage half. When engaged in the receptacles of the first cage half and / or the second cage half, the connecting elements are positively locked together and form bearing cage webs, between which several bearing cage pockets are formed to receive the rolling elements of the rolling bearing.In contrast to certain one-piece cages that only grip the rolling elements on one side and therefore do not reliably prevent the rolling elements from being ejected under high loads, the design of the bearing cage as a two-piece bearing cage has the advantage that the cage provides a secure hold and stability even at high rotational speeds, thereby preventing ejection or deformation of the bearing cage.
[0012] The first and second cage halves are connected by the interlocking of the connecting elements and their receptacles. To ensure a secure hold between the two cage halves, even at high rotational speeds, the connecting elements and receptacles feature a positive locking mechanism. This ensures a secure connection between the two cage halves, preventing a shielding effect (i.e., cage expansion) at high rotational speeds and thus avoiding deformation of the bearing cage.
[0013] According to one embodiment, the first cage half and / or the second cage half have connecting elements extending from the annular base body. In this embodiment, the connecting elements are thus part of one or both cage halves, with the other cage half having the corresponding number of connecting element receptacles. Alternatively, the connecting elements can also be designed as separate elements, distinct from both cage halves. 2024P00186DE
[0014] According to one embodiment, the connecting elements project beyond the first cage half and / or the second cage half after engaging the connecting element receptacles and are designed to be deformed, in particular to be melted by the application of heat, in order to form a positive connection with the connecting element receptacles of the first cage half and / or the second cage half.
[0015] Unlike previous cages, which were connected via a snap-fit mechanism, the positive locking system used here, created by heat, ensures a permanent connection between the two cage halves. Furthermore, a heat source that simply melts or deforms the connecting elements to create this positive locking is preferably sufficient. A complex and costly process such as ultrasonic welding is not required.
[0016] Instead of a form-fit connection through heating, cold forming can also be used. In this case, the fasteners are not melted, but pressed into the fastener receptacles by cold forming.
[0017] According to a further embodiment, the connecting elements and / or the connecting element receptacles are connected at least at the respective contacting surfaces by a layer consisting of a molten material of the connecting element.
[0018] According to a preferred embodiment, the first cage half, on the side facing away from the second cage half, and / or the second cage half, on the side facing away from the first cage half, have recesses in the area of the connecting element receptacles for receiving the molten portion of the connecting elements. These recesses have the advantage that the molten material of the projecting connecting elements can be collected in these recesses, thus homogeneously sealing the outer surface of the bearing cage. The homogeneous outer surface prevents, for example, lubricant located in the area of the bearing and the bearing cage from collecting in recesses on the cage body and thus no longer being available for the lubricant flow and therefore for the lubrication of the rolling elements. Furthermore, the homogeneous outer surface enables the rolling elements to be guided smoothly over the cage webs. 2024P00186DE
[0019] According to another embodiment, the connecting elements are cylindrical. In particular, the connecting elements can terminate opposite the base body in a truncated cone. Alternatively, the connecting elements can terminate opposite the base body in a rounded shape. Other shapes are also possible. In any case, the projecting portion of the connecting elements is designed to melt or otherwise deform upon the application of heat, particularly by force. For example, the connecting elements can be made of a plastic material that has a lower melting point than the rest of the cage material. This ensures that only the projecting portion, which is intended to form the positive connection, is melted.
[0020] The fasteners and fastener receptacles can be round or oblong. In particular, the respective shapes can be manufactured using machining processes, for example, by a milling machine.
[0021] The connecting elements can also be in the form of other fasteners, such as screws, rivets, or similar components, suitable for joining the two cage halves. In this case as well, a positive fit is created between the connecting elements and their receptacles.
[0022] According to another embodiment, a cage web between two cage pockets can be formed by two connecting elements and two connecting element receptacles, the two of which are engaged with each other. The advantages of this design are that there are two positive-locking connections per cage web, thus achieving greater stability of the connection between the two cage halves. Furthermore, the strength of the respective cage web can be increased by using two positive-locking connections. It is also possible to provide two connecting elements and corresponding connecting element receptacles for some cage webs, whereas for other cage webs only one connecting element with a corresponding connecting element receptacle is provided.
[0023] According to another embodiment, the connecting element receptacles are designed as through-holes into which the connecting elements can be inserted. When the two cage halves are assembled, these are engaged by the 2024P00186DE
[0024] The connecting elements are first held in position relative to each other within the through-holes of the connecting element receptacles. As explained above, the protruding portion of the connecting elements can be melted by applying heat, thereby fixing and joining the two cage halves. This prevents the rolling elements from jamming between the two cage halves in the fully joined cage, as the through-holes ensure a defined distance between the two cage halves and a secure alignment of the cage pocket halves.
[0025] According to a further embodiment, the cage webs formed by a connecting element and a connecting element receptacle each have a homogeneous outer surface. This homogeneous outer surface prevents, for example, lubricant located in the area of the bearing and the bearing cage from collecting in recesses on the cage body and thus no longer being available for the lubricant flow and lubrication of the rolling elements. Furthermore, the homogeneous outer surface enables the rolling elements to be guided smoothly over the cage webs.
[0026] According to a further embodiment, each cage half has several cage pocket half-shells, wherein the cage pocket half-shells in particular have a toroidal pocket geometry. This toroidal pocket geometry allows the rolling element, in particular a ball, to be partially enclosed both radially inside and radially outside, resulting in particularly good rolling element guidance.
[0027] According to a preferred embodiment, the first and second cage halves are made of plastic, in particular an injection-moldable plastic. A plastic such as PEEK, PA4.6, or PA6.6, preferably containing 15% to 30% carbon or glass fiber, is particularly advantageous. Alternatively, the plastic can also be unreinforced. Such plastic cage halves are easy to manufacture and simple to assemble, even in a two-part form. Since the bearing cage proposed here includes the connecting elements and complementary connecting element receptacles described above, the plastic cage remains stable even at high speeds. Such a lightweight plastic cage can be used in particular in ball bearings, especially deep groove ball bearings. High speeds can be achieved by using a plastic cage because it has low weight and good friction and wear properties.Furthermore, the 2024P00186DE plastic cage is easy and cost-effective to manufacture. The first and / or second cage halves can be machined, injection molded, and / or produced using an additive manufacturing process.
[0028] In another embodiment, the connecting elements, when they are part of the first or second cage half, have a radius relative to the base body of the respective cage half. This radius has the advantage of stabilizing the connecting elements and reducing the risk of them breaking off.
[0029] According to another aspect, a rolling bearing is proposed. This rolling bearing comprises an inner bearing ring, an outer bearing ring, and several rolling elements that roll on raceways between the bearing rings. These elements are held at uniform intervals by the bearing cage, which is designed as a two-part cage, as described above. As already explained, the two-part bearing cage has the advantage that even at high speeds, the cage does not bend, thus preventing the rolling elements from being ejected or the cage from deforming. Therefore, contact between the bearing cage and the outer or inner bearing ring can also be avoided. In this way, neither the friction in the rolling bearing is increased, nor is premature bearing failure to be expected.
[0030] In another aspect, a method for manufacturing a two-part bearing cage according to the invention for a rolling bearing for receiving rolling elements is proposed, comprising the following steps:
[0031] - Providing connecting elements and a first cage half and a second cage half, wherein the first cage half and / or the second cage half have complementary connecting element receptacles for the connecting elements;
[0032] - Assembling the first cage half with the second cage half by inserting the connecting elements into the connecting element receptacles of the first cage half and / or the second cage half, whereby the connecting elements project beyond the first cage half and / or the second cage half after engaging in the connecting element receptacles;
[0033] - Deformation, in particular heating, of the projecting connecting elements to form a positive fit with the complementary connecting element receptacles 2024P00186DE of the first cage half and / or the second cage half, in order to connect the first cage half and the second cage half.
[0034] In one embodiment, the first process step can involve forming a first cage half, with axially extending connecting elements and / or connecting element receptacles, and / or a second cage half, also with axially extending connecting elements and / or connecting element receptacles, wherein the first and / or second cage half are formed from plastic material. The first process step can also include forming the connecting elements as separate components. Such plastic cages are lightweight and can be used, in particular, in ball bearings. High rotational speeds can be achieved by using a plastic cage because it is lightweight and has good friction and wear properties. Furthermore, the plastic cage is easy and inexpensive to manufacture. The first and / or second cage half can be injection molded and / or produced by an additive manufacturing process.The cage components are preferably manufactured by machining. Alternatively, the cage components can also be manufactured by injection molding.
[0035] In a further embodiment, the process step of heating the projecting connecting elements to form a positive fit with the complementary connecting element receptacles of the first and / or second cage half can include heating the projecting portion of the connecting elements. During the heating process, after engagement with the connecting element receptacles, the projecting portion of the connecting elements melts, with the material remaining in the recesses of the connecting element receptacles and forming a homogeneous outer surface of the bearing cage. The molten portion forms a type of plastic rivet. The advantages of the manufacturing process for the two-part bearing cage result from the cost-effective and machine-machinable two-part bearing cage design, particularly for small production runs, as well as from the low tooling costs due to the simplified heating process.
[0036] Further advantages and advantageous embodiments are specified in the description, the drawings, and the claims. In particular, those described in 2024P00186DE are relevant.
[0037] The description and combinations of features shown in the drawings are purely exemplary, so that the features may also exist individually or in different combinations.
[0038] Brief character description
[0039] The invention will now be described in more detail with reference to exemplary embodiments illustrated in the drawings. These exemplary embodiments and the combinations shown therein are purely illustrative and do not define the scope of protection of the invention. The scope of protection is defined solely by the appended claims.
[0040] They show:
[0041] Fig. 1 : a schematic perspective view of a first and second cage half of a two-part bearing cage in the unassembled state;
[0042] Fig. 2: a schematic perspective view of the two-part bearing cage in its assembled state;
[0043] Fig. 3: a cross-section through the schematic perspective view of the two-part bearing cage of Fig. 2;
[0044] Fig. 4: a sectional view of the connection of the two-part bearing cage after assembly and heating;
[0045] Fig. 5: a schematic perspective view of a first and second cage half of a two-part bearing cage in the unassembled state according to a further embodiment;
[0046] Fig. 6: a cross-section through the schematic perspective view of the two-part bearing cage of Fig. 5 in the assembled state with partially inserted connecting elements;
[0047] Fig. 7: a cross-section through the schematic perspective view of the two-part bearing cage of Fig. 5 with fully inserted connecting elements; and
[0048] Fig. 8: a cross-section through the schematic perspective view of the two-part bearing cage of Fig. 5 with fully inserted and deformed connecting elements.
[0049] Detailed description of the invention
[0050] In the following, identical or functionally equivalent elements are identified by the same reference symbols. 2024P00186DE
[0051] Fig. 1 shows a schematic perspective view of a bearing cage 1 for a rolling bearing, which is composed of a first cage half 100 and a second cage half 200. Each of the cage halves 100 and 200, respectively, has an annular base body 10. As can be further seen in Fig. 1, the bearing cage 1 comprises several cage half-pockets 4a, 4b, which, after the cage halves 100, 200 are assembled, form several cage pockets 4 in which rolling elements (not shown) can be received. The cage pockets 4 have a toroidal shape. The toroidal design allows the rolling elements, for example, balls, to be well guided and partially enclosed in the cage pockets 4. The rolling bearing can be, for example, a deep groove ball bearing. Other types of rolling bearings and rolling elements, for example, a roller bearing with rollers, are also possible.
[0052] Fig. 1 shows axially extending connecting elements 6 that extend axially from the annular base body 10 of the first cage half 100. The second cage half 200 has complementary connecting element receptacles 8, 12 for the connecting elements 6 of the first cage half. The connecting elements 6 are preferably cylindrical, with each connecting element 6 terminating in a truncated cone 7 opposite the base body 10 in the embodiment shown here. Alternatively, the connecting element 6 can terminate in a rounded shape or in other shapes (not shown). The connecting element receptacles 8, 12 are designed as through-holes 12 into which connecting elements 6 can be inserted. On the side of the second cage half 200 facing away from the first cage half 100, the connecting element receptacles 8, 12 have recesses or countersinks 8, which are described in more detail below.
[0053] Figures 2 and 3 show a schematic perspective view of the two-part bearing cage 1 in its assembled form. The views show that the cage web 2 is formed by the engagement of the connecting element 6 of the first cage half 100 with the connecting element receptacle 8, 12 of the second cage half 200. The engagement of the connecting elements 6 with the connecting element receptacles 8, 12 is designed such that the cage halves 100, 200 form a homogeneous outer surface 14. Figures 2 and 3 also show that, after the cage halves 100, 200 are assembled, the bearing cage 1 forms several cage pockets 4 in which rolling elements (not shown) can be accommodated. Figure 2 further shows that the connecting elements 6 of the first cage half 100 are designed according to 2024P00186DE
[0054] The connecting elements 6 project over the second cage half 200 into the connecting element receptacles 8, 12. Upon application of heat, the projecting portion 7 of the connecting elements 6 melts to form a positive fit 28 (see Fig. 4) with the recesses 8 of the connecting element receptacles of the second cage half 200.
[0055] As mentioned above, Figures 1, 2, and 3 show that the second cage half 200 has recesses or indentations 8 on the side facing away from the first cage half 100 in the area of the connecting element receptacles. These serve to receive the molten portion of the connecting elements 6. This has the advantage that the outer surface of the bearing cage 1 has a homogeneous finish after melting. The bearing cage 1 is preferably made of plastic, in particular of an injection-moldable plastic, preferably PEEK, PA4.6, or PA6.6, preferably with a carbon or glass fiber content of 15%–30%.
[0056] Fig. 4 shows a schematic view of the connection between the first cage half 100 and the second cage half 200. Here, the projecting connecting element 6 of the first cage half 100 forms a positive fit 28 with the connecting element receptacle 8, 12 of the second cage half 200 after the application of heat. As described above, the molten portion of the connecting elements 6 is collected in the recesses 8.
[0057] It should be noted that cold forming is also possible instead of deformation by heat. In this case, the projecting portion 7 of the connecting elements 6 is not melted by heat, but is pressed into the recesses or indentations 8 by cold forming. Furthermore, the first cage half 100 also has connecting element receptacles and the second cage half 200 has corresponding connecting elements, and the connecting element receptacles and connecting elements can be distributed arbitrarily between the cage halves.
[0058] In a further embodiment, described in Figures 5 to 8, the connecting elements 6 are designed as separate elements, distinct from the cage halves 100, 200. The cage halves 100, 200 and the connecting elements 6 are constructed similarly to the cage halves 100, 200 and connecting elements 6 of Figures 1 to 4. Therefore, only the differences are described in more detail below. 2024P00186DE
[0059] According to the embodiment described in Figures 5 to 8, both the first and second cage halves 100, 200 have connecting element receptacles 8, 12. To connect the two cage halves 100, 200 to each other, the connecting elements 6 are inserted from one side, in the example shown, from the side of the first cage half 100 (see Figure 6). The connecting elements 6 can, for example, be cylindrical, with one end 16 forming a cone or a thickening of another shape.
[0060] This end 16 comes to rest in the recess 8 of the first cage half 100 (see Figs. 7 and 8). The end of the connecting element 6 protruding from the second cage half 200 can then be deformed, for example by heating, and fills the recess 8 of the second cage half 200 (see Fig. 8) to form the positive connection. It is also possible to deform both ends of the connecting element 6 instead of providing a thickened end 16.
[0061] In summary, a bearing cage, a rolling bearing with a bearing cage, and a method for manufacturing a bearing cage are proposed. The bearing cage ensures secure hold and stability of the two interconnected cage halves, even at high rotational speeds. For this purpose, the connecting elements and connecting element receptacles of the first and second cage halves form a positive fit, for example, after the application of heat, in order to subsequently join the two cage halves.
[0062] 2024P00186DE
[0063] Reference symbol list
[0064] 1 bearing cage
[0065] 2 cage bridges
[0066] 4 cage pockets
[0067] 4a Cage pocket half-shells
[0068] 4b Cage pocket half shells
[0069] 6 Connecting element
[0070] 7 truncated cones
[0071] 8 Recess / countersink for the connecting element receptacle
[0072] 10 basic shapes
[0073] 12 through holes
[0074] 14 homogeneous outer surface
[0075] 16 conical end
[0076] 28 Form closure
[0077] 100 first cage half
[0078] 200 second cage half
Claims
2024P00186DE Patent claims Bearing cage for a rolling bearing and manufacturing process of such a bearing cage 1. Two-part bearing cage (1) for a rolling bearing with a first cage half (100) and a second cage half (200), each having an annular base body (10), characterized in that the bearing cage (1) has axially extending connecting elements (6), wherein the first cage half (100) and / or the second cage half (200) have complementary connecting element receptacles (8, 12) for the connecting elements (6), wherein the connecting elements (6) engage in the connecting element receptacles (8, 12) of the first cage half (100) and / or the second cage half (200), wherein the connecting elements (6) can be connected to each other by a positive locking when engaging in the connecting element receptacles (8, 12) and form bearing cage webs (2) between which several bearing cage pockets (4) are formed for receiving the rolling elements of the rolling bearing.
2. Two-part bearing cage according to claim 1, wherein the first cage half (100) and / or the second cage half (200) have the connecting elements (6) which extend axially from the annular base body (10).
3. Two-part bearing cage according to claim 1 or 2, wherein the connecting elements (6) project beyond the first cage half (100) and / or the second cage half (200) after engaging the connecting element receptacles (8, 12) and are designed to be deformed, in particular to be melted by the application of heat, in order to form the positive locking (28) with the connecting element receptacles (8, 12) of the first cage half (100) and / or the second cage half (200) in order to connect the first cage half (100) and the second cage half (200). 2024P00186DE 4. Two-part bearing cage (1) according to claim 1 or 2, wherein the first cage half (200) has recesses (8) on the side facing away from the second cage half (200) in the area of the connecting element receptacles (8, 12) and / or the second cage half (200) has recesses (8) on the side facing away from the first cage half (100) in the area of the connecting element receptacles (8, 12) for receiving the molten portion of the connecting elements (6).
5. Two-part bearing cage (1) according to one of the preceding claims, wherein the connecting elements (6) are cylindrical, wherein in particular the connecting elements (6) terminate opposite the base body (10) in a truncated cone (7).
6. Two-part bearing cage (1) according to one of the preceding claims, wherein the connecting element receptacles (8, 12) are designed as through holes (12) into which the connecting elements (6) can be inserted.
7. Two-part bearing cage (1) according to one of the preceding claims, wherein the cage webs (2) formed by a connecting element (6) and a connecting element receptacle (8, 12) each have a homogeneous outer surface (14).
8. Two-part bearing cage (1) according to one of the preceding claims, wherein each cage half (100, 200) has several cage pocket half-shells (4a, 4b), wherein the cage pocket half-shells (4a, 4b) in particular have a toroidal pocket geometry.
9. Rolling bearings with an inner bearing ring, an outer bearing ring and several rolling elements rolling on raceways between the bearing rings, which are held at uniform intervals from each other by the bearing cage, characterized in that the bearing cage is designed as a two-part bearing cage (1) according to one of the preceding claims.
10. Method for manufacturing a two-part bearing cage (1) for a rolling bearing for receiving rolling elements according to any one of claims 1 to 8, comprising the following steps: 2024P00186DE - Providing connecting elements (6) and a first cage half (100) and a second cage half (200), wherein the first cage half (100) and / or the second cage half (200) have complementary connecting element receptacles (8, 12) for the connecting elements (6); - Assembling the first cage half (100) with the second cage half (200) by inserting the connecting elements (6) into the connecting element receptacles (8, 12) of the first cage half (100) and / or the second cage half (200), wherein the connecting elements (6) project beyond the first cage half (100) and / or the second cage half (200) after engaging in the connecting element receptacles (8, 12); - Deformation, in particular heating, of the projecting connecting elements (6) to form a positive connection with the connecting element receptacles (8, 12) of the first cage halves (100) and / or the second cage halves (200) in order to connect the first cage half (100) and the second cage half (200).