Bearing cage for rolling bearings

Abstract

To provide a two-component bearing holder that is suitable for high rotation speed, and resists a high radial load and axial load.SOLUTION: A two-component bearing holder for a rolling bearing includes a first holder half body 100, and a second holder half body 200 that is preferably configured as the same as the first holder half body. Each of the bearing holder half bodies includes an annular base body, a pin 6-1 axially extending from that, and a pin receiving portion 8-2 complementarily configured. The pin 6-2 of the one holder half body engages with the other pin receiving portion 8-1. At the time of engaging at the pin receiving portions, the pins form bearing holder bridges 2, and a bering holder pocket 4 is formed between them to receive a rolling body of the rolling bearing. The pin and / or pin receiving portion includes a sacrificial material on respective contact surfaces. The sacrificial material is configured to melt by the action of supersonic wave for connecting the first holder half body 100 and the second holder half body 200.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The invention relates to a two-part bearing cage for rolling bearings according to the preamble of claim 1. Furthermore, the invention relates to an ultrasonic welding device according to claim 11. Furthermore, the invention relates to a bearing cage for rolling bearings according to the preamble of claim 12. [Background technology]

[0002] It is known to use two-part bearing cages consisting of identical bearing cage halves in various applications, for example ball bearings. However, in the bearing cages used so far, the retaining elements used to connect the two bearing cage halves can bend radially outward at high speeds, causing the cage to expand and come into contact with the outer ring, resulting in increased friction or jamming of the rolling elements. The known bearing cages are also not suitable for high radial and axial loads, since in the event of failure of the retaining elements used, the radial and axial retention of the cage is lost. Summary of the Invention [Problem to be solved by the invention]

[0003] It is therefore an object of the present invention to provide a two-part bearing cage which is also suitable for high rotational speeds and which withstands high radial and axial loads. [Means for solving the problem]

[0004] This object is achieved by a bearing cage according to claims 1 and 12 and by an ultrasonic welding device for producing such a bearing cage according to claim 11.

[0005] The bearing cage comprises a first cage half and a second cage half preferably configured similarly to the first cage half, each cage half including an annular base body with pins extending axially therefrom and complementary configured pin receivers, the pins of one cage half being engageable with the pin receivers of the other cage half, the pins forming a bearing cage bridge and bearing cage pockets therebetween for receiving rolling elements of a rolling bearing.

[0006] To reliably hold the two cage halves together even at high rotational speeds, the pins and / or pin receivers contain a sacrificial material on their respective contact surfaces, which melts under the action of ultrasound when the first and second cage halves are assembled, and subsequently connects the two cage halves.

[0007] The use of ultrasound allows a quick connection of the cage halves, which is simple to perform and durable. To connect the first and second cage halves, the sacrificial material is melted by the action of ultrasound and can spread to the contact surfaces of the two cages, not only at the contact surface where it was originally present, but also by spreading in the molten state and flowing into any gaps that may exist between the cage halves. In this way, the connection between the two cage halves can be further improved.

[0008] According to one embodiment, each pin receiver includes an axially extending ring portion located radially outwardly, which supports radially outwardly each pin that engages in the pin receiver. The radial support of each pin prevents the pin from bending radially outwardly. This ensures that there is no contact between the bearing cage and the outer ring, even at high rotational speeds. In this way, there is no increased bearing friction and no premature bearing failure to be predicted.

[0009] Here, it is preferred if the axially extending ring portion is formed on the annular base body of the cage half, this integral design between the ring portion and the annular base body allows the radial forces introduced into the ring portion to be diverted to the base body, thus preventing the cage from expanding radially outwards even in the case of high stresses on the ring portion.

[0010] According to a further exemplary embodiment, each pin comprises a radially outer transition part which interacts with a ring part of the pin receiver in such a way that the cage bridge formed by the pin and the pin receiver has a uniform outer surface, which ensures that, for example, lubricant in the region of the bearing and the bearing cage does not collect in recesses in the cage body, which would cause lubricant flows and thus prevent lubrication of the rolling elements. Furthermore, the uniform outer surface allows trouble-free guiding of the rolling elements through the cage bridge.

[0011] During assembly of the two cage halves, they are first held apart by the sacrificial material. When the sacrificial material melts under the action of ultrasound, this spacing disappears and the two cage halves are forced closer together. The transition ensures that during melting of the sacrificial material, the two cage parts cannot be pressed further together than required, as they will abut against the transition. In this way, with a fully connected cage, it is possible to prevent the rolling elements from being pinched between the two cage parts, as the transition ensures a predetermined spacing between the cage halves.

[0012] According to a further embodiment, each cage half comprises a cage pocket half, which has a toroidal pocket shape that is fitted radially inwardly to a spherical shell and extends cylindrically radially outwardly. This toroidal pocket shape allows the rolling elements, in particular the balls, to be completely confined radially inward, resulting in a particularly good rolling element guiding. Furthermore, the cylindrical outer design of the pocket shape does not directly confine the rolling elements radially outwardly, but leaves gaps between the rolling elements and the pockets, which allow the lubricant to penetrate therein and thus allows a good supply of the lubricant.

[0013] According to a further embodiment, the cage is manufactured from plastic, in particular from an injection-moldable plastic. Particularly advantageous here are plastics such as PEEK, PA4.6, PA6.6, preferably manufactured with a carbon or glass fiber content of 15% to 30%. Such plastic cages are easy to manufacture and also easy to assemble in two parts. The bearing cage proposed here uses the above-mentioned pins for support, so that the plastic cage is stable even at high speeds. Such lightweight plastic cages can be used in particular for ball bearings. By using a plastic cage, high speeds can be realized due to the light weight of the plastic cage.

[0014] According to further embodiments, the sacrificial material is wedge-shaped, pyramidal or conical. Other shapes are possible. In any case, the sacrificial material is provided as additional material to the pin and / or the pin receiver, and the sacrificial material is melted under the action of ultrasound. The sacrificial material is preferably made of a plastic material that has a lower melting temperature than the remaining cage material.

[0015] In order to be able to melt the sacrificial material by the action of ultrasonic waves, the first retainer half and / or the second retainer half may comprise a primary contact surface adjacent to the contact surface, which allows for particularly good conduction of ultrasonic waves to the contact surface and / or the sacrificial material. An ultrasonic welding device is preferably applied to the primary contact surface in order to direct the ultrasonic waves via the primary contact surface to the contact surface or the sacrificial material.

[0016] According to a further embodiment, the first and / or second retainer halves include a secondary contact surface opposite the contact surface and configured to direct ultrasonic waves to the contact surface and / or the sacrificial material. Here, the secondary contact surface may be opposite the contact surface in the axial direction of the retainer. In this way, the sacrificial material can be heated by ultrasonic waves from two axial sides (by the primary and secondary contact surfaces).

[0017] Furthermore, a wedge-shaped surface may be formed on each retainer bridge, the wedge-shaped surface being configured to guide ultrasonic waves from the secondary contact surface to the contact surface. The wedge-shaped surface may comprise a material that is particularly suitable for the transmission of ultrasonic waves. This material may be realized, for example, by a plastic fiber component of the retainer material. The transmission of ultrasonic waves to the secondary contact surface accelerates the dissolution of the sacrificial material.

[0018] According to a further aspect, an ultrasonic welding device adapted to the shape of such a two-part bearing cage is proposed, which consists of a first part which is applied to the first cage half and a second part which is applied to the second cage half.

[0019] According to a further aspect, a bearing cage for a rolling bearing is proposed, comprising a first cage half and a second cage half, preferably constructed identically to the first cage half, each of the bearing cage halves comprising an annular base body and pins extending therefrom in the axial direction and complementary pin receivers. The pins of one cage half engage in the pin receivers of the other cage half, and by engagement with the pin receivers the pins form a bearing cage bridge, between which bearing cage pockets are formed for receiving the rolling elements of the rolling bearing. The pins and / or the pin receivers are connected at least at their respective contact surfaces by a layer composed of a molten sacrificial material. The sacrificial material can be composed of the same material as the two cage halves.

[0020] The ultrasonic welding process melts the sacrificial material and leaves it within the cage structure, meaning that the layers interconnecting the pins and pin receivers are constructed as welded connections and are located entirely inside the cage, with no weld seams or weld points visible from the outside.

[0021] Further advantages and advantageous embodiments are specified in the present specification, the drawings and the claims, where it is to be noted that the combinations of features specified in the present specification and the drawings are merely exemplary and that the features can be combined individually or in other ways.

[0022] In the following, the present invention will be described in more detail using exemplary embodiments depicted in the drawings, where the exemplary embodiments and the combinations shown in the exemplary embodiments are merely exemplary and are not intended to define the scope of the present invention, which is defined only by the pending claims. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 shows a schematic perspective view of a two-part bearing cage. [Diagram 2] FIG. 2 shows a schematic detail view of the first cage half. [Diagram 3] FIG. 2 shows a schematic detail view of the second cage half. [Figure 4] 4 illustrates a first exemplary embodiment of the sacrificial material of FIGS. 2 and 3. [Diagram 5] 4 illustrates a second exemplary embodiment of the sacrificial material of FIGS. 2 and 3. [Figure 6] 4 illustrates a third exemplary embodiment of the sacrificial material of FIGS. 2 and 3. [Figure 7] 1 shows a schematic diagram of the assembly of the two cage halves. [Figure 8] 4 shows a further schematic view of the assembly of the two cage halves. [Figure 9] 4 shows a further schematic view of the assembly of the two cage halves. [Figure 10] FIG. 2 shows a schematic detail view of a retainer half including a contact surface for an ultrasonic welding device. [Figure 11] FIG. 2 shows a further schematic detail of the retainer halves including the contact surfaces for the ultrasonic welding device. [Figure 12] FIG. 2 shows a further schematic detail of the retainer halves including the contact surfaces for the ultrasonic welding device. [Figure 13] FIG. 2 shows a further schematic detail of the retainer halves including the contact surfaces for the ultrasonic welding device. [Figure 14] 1 shows a schematic perspective view of a holding device for an ultrasonic welding device. [Figure 15] 15 shows a schematic perspective view of the retention device of FIG. 14 including an assembled bearing retainer. [Figure 16] A cross-sectional view of FIG. 15 is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] In the following, identical or functionally equivalent elements are indicated with the same reference numbers.

[0025] FIG. 1 shows a schematic spatial view of a bearing cage for a ball bearing 1, which is composed of a first bearing cage half 100 and a second bearing cage half 200. Here, the bearing cage halves 100 and 200 are constructed in the same way. As can be further seen from FIG. 1, the bearing cage 1 comprises a bridge 2 which forms a cage pocket 4 between them, which can receive rolling elements (not shown). The cage pocket 4 here is of toroidal shape, which means that the cage pocket 4 is constructed spherically at the radial inner side 4-1 and cylindrically at the radial outer side 4-2. This toroidal design ensures that the rolling elements, i.e. the balls, are properly guided at the radial inner side 4-1 and completely surrounded by the pocket 4, while being spaced from the bearing cage 1 in the radial outer area 4-2. This allows the lubricant to penetrate into the gap between the rolling elements and the bearing cage 1, which allows a particularly good lubrication of the balls. 1, it can be seen that the cage bridge 2 is formed by the engagement of the pins 6-1, 6-2 with corresponding pin receiving portions 8-1, 8-2 of the respective cage halves 100, 200. The engagement of the pins 6-1, 6-2 with the pin receiving portions 8-2, 8-1 is configured such that both radial and axial fixation of the cage halves 100, 200 is possible.

[0026] Each cage half 100 comprises an annular base body 10 through which the pins 6 extend, forming a pin receiving portion 8. Here, each pin receiving portion 8 comprises an axially extending ring portion 12 which extends axially over the pins 6 when the pins 6 are received therein and which supports the pins 6 radially outward. This axial ring portion 12 ensures that even under high centrifugal forces the cage pins 6 do not bend radially outward and come into contact with the bearing ring receiving the bearing cage 1, which would increase friction and potentially lead to premature failure of the bearing. Furthermore, from figures 2 and 3 it can be seen that the ring portion 12 is formed integrally with the annular base body 10. This allows radial forces to be supported and deflected towards the base body 10, so that bending open of the cage 1 does not occur even under high radial loads.

[0027] To achieve a particularly good engagement and a uniform outer surface 14 of the bearing cage 100, as shown for example in Fig. 1, the pin 6 includes a transition portion 16 which interacts with the ring portion 12. The design of the pin 6 and the pin receiver 8 can also be seen in the enlarged views of Figs. 2 to 6.

[0028] 2 shows a schematic view of the cage halves 100, 200. To enable the two cage halves 100, 200 to be correctly assembled, the pin receiver 8 is provided with a side surface 18, which serves as a centering surface for the corresponding pin 6. The pin receiver 8 includes a centering surface 20 for the correct insertion of the pin 6. Corresponding stop surfaces 22, 24 are provided on the pin receiver 8 and on the pin 6. These stop surfaces 22, 24 in addition to the transition 16 ensure that the two cage halves 100, 200 do not press together too much, but rather abut against each other at the stop surfaces 22, 24. In this way, the cage 1 has sufficient space for the balls.

[0029] The sacrificial material 28 is provided on the pin 6 or on the pin receiver 8 or on both and is melted by ultrasound after assembly of the cage halves 100, 200. Here, the sacrificial material is provided on the surfaces of the pin 6 and / or on the pin receiver 8, which surfaces are in contact with each other in the assembled state. The sacrificial material can have various shapes, for example, a wedge shape (see FIG. 4), a cone shape (see FIG. 5), or a pyramidal or spherical shape. Instead of the pin 6 as shown in FIGS. 4 and 5, the sacrificial material can also be provided on the pin receiver 8, as shown in FIG. 6. Furthermore, the sacrificial material can be provided on both the pin 6 and the pin receiver 8.

[0030] 7 to 9 illustrate the assembly of the two cage halves 100, 200. During assembly of the two symmetric cage halves 100, 200, they are radially aligned using the centering surface 19 and circumferentially aligned by the surfaces 20, 26. This has the advantage that it allows to compensate for distortions, deformations or dimensional deviations that may be caused by the manufacturing process of the cage halves 100, 200.

[0031] During the assembly of the two cage halves 100, 200, a gap of a few millimeters remains between the two cage halves. When the sacrificial material 28 melts by ultrasonic welding, it flows into the connecting surfaces 30, 32, 34 (see FIG. 9). This makes it possible to eliminate possible clearances between the cage halves 100, 200 that may occur due to manufacturing tolerances. Therefore, during the operation of the bearing, no relative movements occur that could lead to damage of the cage 1.

[0032] The stop surfaces 22, 24 define the axial spacing of the cage halves. Since the axial spacing is defined by these surfaces, a constant width of the ball pockets 4 can be ensured. This ensures that the balls do not jam in the pockets during assembly or operation of the bearing, since a minimum width cannot be exceeded. Such jamming can occur due to the expansion of different materials due to different temperatures, for example when using steel or ceramic balls and plastic cages. Furthermore, the axial stop by the stop surfaces 22, 24 also makes it possible to avoid possible gaps in the pockets 4, which would have a negative effect during operation. Such gaps can lead to wear of the cage and balls and can have a negative effect on the lubricating film.

[0033] In Figures 10 to 13, contact surfaces 36, 38, 42 for conducting ultrasonic waves to the pin 6 or pin receiver 8 and the corresponding sacrificial material 28 are shown. The ultrasonic welding device may include a primary contact surface 36 and two secondary contact surfaces 38 per retainer bridge, where the primary contact surface 36 directly abuts the sacrificial material 28. For example, as shown in Figure 13, the primary contact surface 36 is opposite the pin receiver 8. In this way, ultrasonic waves can be conducted directly to the sacrificial material 28. Thus, by the primary contact surface 36, ultrasonic waves are conducted directly to the surface containing the sacrificial material 28 or to the opposite surface.

[0034] Furthermore, the ultrasonic waves are directed via the adjacent surfaces 38 and are also conducted to the sacrificial material 28 via the wedge-shaped retainer bridge halves 40. Here, the retainer 1 can include fiber parts in plastic, in particular carbon fiber parts, which allow good conduction of the ultrasonic waves to the sacrificial material 28. The sacrificial material 28 melts particularly well, since the primary and secondary contact surfaces 36, 38 and the retainer bridge halves 40 allow the ultrasonic waves to be conducted to the pin receiving portion 8 or the opposite surface and to the pin 6 or the opposite surface.

[0035] In some embodiments of the cage 1, the ultrasonic welding device can be extended to a further primary contact surface 42 located on the pin 6. This is particularly useful for a wide variation of the cage 1, since the ultrasonic waves cannot advance sufficiently if the spacing between the two weld points per cage pocket bridge increases. This can be prevented by the further primary contact surface 42.

[0036] 14 to 16 show a holding device 300 of an ultrasonic welding device. The holding device 300 shows a negative profile 44 on the rear side of the cage. In the negative profile 44 there is a corresponding number of ball pockets, a support surface 46 for the bearing inner ring and a centering device 48 for the bearing inner ring. Since the rear surfaces of the pin receiving part 8 and the pin 6 now have to support the forces exerted during ultrasonic welding, the negative profile 44 is designed in such a way that these surfaces are mainly supported. Furthermore, in order to achieve high positional accuracy during ultrasonic welding, a rotation of the cage halves 100, 200 around the bearing rotation axis is prevented. This is also achieved by the negative profile 44 and the support surfaces 46, 48.

[0037] The support surface 46 vertically supports the bearing inner ring during ultrasonic welding. Furthermore, the centering device 48 of the bearing inner ring positions the inner ring so that it does not collide with the ultrasonic welding device due to the clearance of the cage. Furthermore, the support surfaces 50, 52 are provided on the cage, and the vertical distance of the support surfaces 50, 52 to the support surface 46 is configured such that there is an enclosed gap 56 between the rolling elements and the cage halves 100, 200. This prevents the rolling elements from directly contacting the vibrating parts, i.e. the cage halves 100, 200 and the ultrasonic welding device, and prevents the bearing from being damaged during the process of the ultrasonic welding device.

[0038] Only the inner bearing ring 58 abuts against the support surface 46. The outer bearing ring 60 is not supported vertically. During ultrasonic welding, a significant preload force 62 acts on the outer bearing ring 60 vertically towards the support surface 46, clamping the bearing parts, the outer bearing ring 60, the rolling elements 54 and the inner bearing ring 58 together. This clamping prevents any relative movement between the bearing parts during the welding process that could damage the bearing.

[0039] In summary, a simple production of a bearing cage by ultrasonic welding is proposed, the resulting cage being able to reliably hold the two cage halves even at high rotational speeds. For this purpose, the pins and / or the pin receivers contain sacrificial material on their respective contacting surfaces, which melts under the action of ultrasound and connects the two cage halves. [Explanation of symbols]

[0040] 1 Bearing cage 2 Bridge 4 Retainer pocket 6-pin 8 Pin Receptacle 10 Base body 12 Axial extending ring portion 14 Uniform outer surface 16 Transition 18, 19, 20 Centering surface 22, 24 Stopping surface 26 Centering surface 28 Sacrificial Materials 30, 32, 34 Connection surface 36 Primary contact surface 38 Secondary contact surface 40 Retainer bridge half 42 Primary contact surface 44 Negative Shape 46 Support surface 48 Centering 50 Support surface 52 Support surface 54 Ball 56 Gap 58 Inner Circle 60 Outer Ring 62 Preload 100 First retainer half 200 Second retainer half 300 Holding device

Claims

1. A bearing retainer half (100), which together with another identically constructed bearing retainer half (200) constitutes a two-part bearing retainer (1) for a rolling bearing, the bearing retainer half including an annular base body (10) and pins (6) extending axially from the annular base body (10), and complementarily constructed pin receivers (8), the pins (6) of the retainer half engaging with the pin receivers (8) of the other retainer half, the pins (6) forming a bearing retainer bridge (2) between which bearing retainer bridges are formed bearing retainer pockets (4) for receiving rolling elements (54) of the rolling bearing, said pin (6) and / or said pin receiving portion (8) comprising a sacrificial material (28) at their respective contact surfaces, said sacrificial material (28) being adapted to be melted by the action of ultrasonic waves to connect said retainer half (100) and said further retainer half (200); In the bearing retainer half, both the pin (6) and the pin receiving portion (8) are disposed between the bearing retainer pockets (4) adjacent to each other in the circumferential direction; The pins (6) each include an axial end wall; The pin receiving portions (8) each include an axial end wall; said sacrificial material (28) being axially located between said axial end wall of said pin (6) and said axial end wall of said pin receiving portion (8) when said pin (6) is located in said pin receiving portion (8).

2. 2. The bearing cage half according to claim 1, wherein each pin receiving portion (8) includes an axially extending ring portion (12) arranged radially outwardly, said ring portion radially outwardly supporting a pin (6) of said other bearing cage which is engaged with said pin receiving portion (8).

3. 3. The bearing retainer half of claim 2, wherein said axially extending ring portion (12) is formed on said annular base body (10) of said retainer half.

4. 4. A bearing cage half according to claim 2 or 3, wherein each pin (6) comprises a radially outer transition portion (16) which interacts with the ring portion (12) of the pin receiving portion (8) of the further bearing cage such that the cage bridge (2) formed by the pin (6) and the pin receiving portion (8) of the further bearing cage has a uniform outer surface (14).

5. 5. The bearing retainer half according to claim 1, wherein the retainer half (100, 200) includes a retainer pocket half shell, and the retainer pocket (4) has a toroidal pocket shape that is configured as a spherical shell on the radially inner side and extends cylindrically on the radially outer side.

6. 6. Bearing cage halves according to any one of claims 1 to 5, wherein the cage halves are manufactured from plastic, an injection mouldable plastic containing 15% to 30% carbon or glass fibre, PEEK, PA4.6 or PA6.

6.

7. The bearing cage half of any one of claims 1 to 6, wherein the sacrificial material (28) is wedge-shaped, pyramidal-shaped or conical-shaped.

8. The bearing retainer half of any one of claims 1 to 7, wherein the retainer half (100) comprises at least one primary contact surface (36, 42) abutting the contact surface and / or the sacrificial material (28) for conducting ultrasonic waves to the contact surface and / or the sacrificial material (28).

9. The bearing retainer half (100) according to any one of claims 1 to 8, wherein the retainer half (100) comprises a secondary contact surface (38) opposite the contact surface, the secondary contact surface (38) being configured to transmit ultrasonic waves to the contact surface and / or the sacrificial material (28).

10. 10. The bearing retainer half of claim 9, wherein each retainer bridge (2) defines a wedge-shaped surface (40) configured to conduct ultrasonic waves from the secondary contact surface (38) to the contact surface.

11. A bearing retainer half (100), which together with another identically constructed bearing retainer half (200) constitutes a two-part bearing retainer (1) for a rolling bearing, the bearing retainer half including an annular base body (10) and pins (6) extending axially from the annular base body (10), and complementarily constructed pin receivers (8), the pins (6) of the retainer half engaging with the pin receivers (8) of the other retainer half, the pins (6) forming a bearing retainer bridge (2) by engagement with the pin receivers (8), and bearing retainer pockets (4) for receiving rolling elements (54) of the rolling bearing being formed between the bearing retainer bridges, the pin (6) and / or the pin receiving part (8) are connected at least at their respective contact surfaces by a layer made of a meltable sacrificial material (28); In the bearing retainer half, both the pin (6) and the pin receiving portion (8) are disposed between the bearing retainer pockets (4) adjacent to each other in the circumferential direction; The pins (6) each include an axial end wall; The pin receiving portions (8) each include an axial end wall; said sacrificial material (28) being axially located between said axial end wall of said pin (6) and said axial end wall of said pin receiving portion (8) when said pin (6) is located in said pin receiving portion (8).

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