Raceway element of a rolling bearing and a retainer for the raceway element

Abstract

Raceway element (2) of a rolling bearing with • - a raceway side with at least one track for rolling-off of rolling bodies of the rolling bearing, and • - an other side being different, particularly opposite to the raceway side with at least one cable groove (14, 16), whereby the course of the cable groove on said side particularly corresponds at least in sections to the course of the track on the raceway side, and whereby at least one sensor cable (20) particularly comprising an optical fiber with a Bragg grating is arranged in the cable groove particularly for at least a spatially resolved detection of mechanical strains, and with an alignment groove (6) being designed to engage with an alignment element (8) of a retainer (4), to which the raceway element is intended to be mounted, particularly for a defined angular positioning and / or an anti-rotation locking between the raceway element and the retainer, whereby at least the shapes and courses of the cable groove and the alignment groove are designed at least the way that any damage of the properly arranged sensor cable by the intended engagement of the alignment element is excluded.

Description

[0001] Raceway element of a rolling bearing and a retainer for the raceway element

[0002] D e s c r i p t i o n

[0003] Technical field of the invention

[0004] The present invention relates raceway element of a rolling bearing and a retainer for the raceway element.

[0005] Background of the invention

[0006] In many technical applications, bearings are used for supporting shafts or the like. Depending on the application, the bearings need to operate under high-speed conditions which have high requirements with respect to lubrication, running accuracy etc. One example for such bearings are machine spindle bearings which are operating under tough high-speed conditions. In order to ensure proper functioning of the bearings, sensors may be used for monitoring the bearings, for example in the form of sensorized bearings, i.e., bearings which comprise a sensor.

[0007] Traditionally in machine spindles, the angular position of the bearing outer ring with respect to the housing is not so important. However, when sensors are to be integrated into the bearing, it may become very important how the bearing ring comprising the sensor is mounted into the housing or whether the bearing ring is stationary or not. When cables need to be guided from the sensor to the outside, this might be only possible when the bearing ring is stationary and the cables will not rotate together with the bearing ring, which could induce damage to the cables. However, in this case, the correct alignment of the bearing ring with respect to the housing or sleeve or any other component might become important as the sensor(s) and / or cables should be correctly arranged on the bearing ring and / or component.

[0008] It is therefore an object of the present invention to provide an improved raceway element of a rolling bearing and an improved retainer for the raceway element in this regard.

[0009] Summary of the invention

[0010] This object is solved by the subject of claims 1 and 6.

[0011] The raceway element of a rolling bearing comprises a raceway side with at least one track for rolling-off of rolling bodies of the rolling bearing and an other side being different to the raceway side with at least one cable groove. The course of the cable groove on said side particularly corresponds at least in sections to the course of the track on the raceway side. Further at least one sensor cable is arranged in the cable groove particularly comprising an optical fiber with a Bragg grating for at least a spatially resolved detection of mechanical strains. The other side comprises further an alignment groove being designed to engage with an alignment element of a retainer, to which the raceway element is intended to be mounted, particularly for a defined angular positioning and / or an anti-rotation locking between the raceway element and the retainer. Thereby at least the shapes and courses of the cable groove and the alignment groove are designed at least the way that any damage of the properly arranged sensor cable by the intended engagement of the alignment element is excluded. In addition at least the majority of sections of the cable groove are distanced to the alignment groove and / or the courses of the grooves are designed with a minimum number of intersections respectively crossings.

[0012] Therewith a structure is created on said side of raceway element, which copes with advantage the demands of a safe accommodation and routing of a sensor cable simultaneously fulfilling requirements of an angular positioning and anti-rotation locking between the raceway element and the retainer, minimizing unwanted influences respectively interferences between the different functionalities.

[0013] According to a preferred embodiment the cable groove and the alignment groove show an intersection, particularly approximately at a right angle, whereby the cable groove particularly is deeper than the alignment groove at least at the intersection, particularly so that the depth of the alignment groove is less than the remaining groove depth of the cable groove with the sensor cable arranged in there. With advantages the sensor cable is safe from any negative mechanical impact from the angular positioning and / or anti-rotation locking functionalities.

[0014] According to another preferred embodiment the cable groove comprises an arc-like branch that continues approximately in the direction of the alignment groove particularly parallel to it for feeding the sensor cable, whereby the continuation of the arc-like branch is particularly angularly distanced to the alignment groove by at least 15°. Also this supports with additional advantages said minimizations of undesired influences particularly from the angular positioning and anti-rotation locking functions onto the sensing functionality and accuracy. Of course, according to an alternative solution, said continuation also can be implemented by a groove directly adjacent to the alignment groove, but with a different depth than the one of the alignment groove, so e.g. it can be implemented as a kind of an axially extending shoulder or step of the alignment groove.

[0015] The raceway element particularly a bearing ring is stationary mounted into or onto the retainer, in particular a housing or sleeve. The bearing ring may be either an outer ring (e.g. mounted into a housing or into a sleeve) or an inner ring of a bearing (e.g. mounted onto a sleeve or a shaft). The raceway element is usually completed with another raceway element which can rotate relative to each other via the rolling bodies in between, which can be held distanced to each other by a bearing cage. This may for example be used as a machine spindle bearing but can also be used in any kind of application, where a bearing ring is mounted into or onto a retainer.

[0016] In order to allow a proper and precise angular arrangement of the raceway element with respect to the retainer, the raceway element comprises the alignment groove and the retainer comprises then alignment element. The alignment groove and the alignment element are configured to engage with each other in order to align the raceway element with the retainer. Particularly, the alignment groove and the alignment element may engage with each other during assembly of the raceway element in or on the retainer and may also engage with each other after the assembly, i.e., in the final position.

[0017] The alignment groove and the alignment element together define a predefined arrangement of the raceway element with respect to the retainer. This provides the advantage that sensors and sensor cables may be used which have a specific position in the raceway element or in the retainer. As the raceway element and the retainer are aligned and thus have the correct position in relation to each other, the sensor elements may be arranged at their specific positions, which are taken into account by the alignment of the raceway element and the retainer which will not damage the sensor elements. Further, the alignment of the raceway element and the retainer will be maintained during operation. This may ensure that potential sensor elements will also not be damaged during operation.

[0018] According to an embodiment, the retainer comprises an abutment element like a stop, wherein the abutment element is configured to abut particularly against a front end of the bearing ring in an assembled position. The abutment element may be a flange of the retainer or may be several discrete elements. In particular, the abutment element may ensure that a bearing ring can be slid in or on the retainer only as far as a position defined by the abutment element. Thus, the abutment element provides a correct end positioning in axial direction.

[0019] According to a further embodiment, the alignment groove is an axially extending recess in the circumferential surface of a bearing ring facing the retainer and the alignment element is configured to engage with the recess. The alignment element may be guided along the axially extending recess, or vice versa, and thus, the bearing ring and the retainer may be aligned with respect to each other. For example, the bearing ring may be slid onto / into the retainer using the guidance of the alignment groove till a contact with the abutment element, as described above.

[0020] According to a further embodiment, the alignment element is formed by one or more protrusion elements which particularly radially protrude from the retainer in the direction of a bearing ring, and which are configured to engage with the axially extending recess. The protrusion elements function as alignment elements in combination with the axially extending recess for ensuring the angular position of the bearing ring with respect to the retainer. At the same time, the radially protruding protrusions elements, when in engagement with the recess, function as anti-rotation means. This means that the protrusion elements prevent movement of the bearing ring with respect to the retainer in circumferential direction.

[0021] The protrusion elements may be formed separately from the retainer and may be inserted into radially extending holes within the retainer. For example, the protrusion elements may be screwed into threads formed at the inner surface of the radially extending holes. Preferably, the radially extending holes may be through holes. In this case, the protrusion elements may be inserted into the through holes from the outside. This may also allow access to the protrusion elements after assembly of the bearing ring and the retainer so that the protrusion elements may be tightened in the final position. Such a tightening may improve the hold between bearing ring and the retainer, thus improving the anti-rotation functionality.

[0022] In a further embodiment, the protrusion elements are preloaded and are compressed during assembly and are snapped into the axially extending recess in the assembled position. The protrusion elements may be springs or may comprise springs which can be compressed during assembly. This provides the advantage that the recess in the bearing ring does not need to be exactly aligned with the protrusion elements during assembly. Rather, the bearing ring and the retainer may be put together in any orientation. At the end, the bearing ring and the retainer may be rotated with respect to each other until the protrusion elements slide into the recess and are decompressed. In this final position, the protrusion elements are snapped into the axially extending recess.

[0023] According to a further embodiment, the protrusion elements are formed as nozzles being connectable to a lubricant supply unit. In this embodiment, the protrusion elements may have through holes through which lubricant may be inserted into the bearing unit. The nozzles may be connected to a pipeline through which lubricant can be supplied to the nozzles and then inside of the bearing. Thus, the alignment element, i.e., the protrusion elements, may provide the functionality of alignment, anti-rotation as well as lubrication.

[0024] The bearing ring may comprise through holes being formed in the recess and extending to the bearing interior. The nozzles may be arranged such that lubricant from the nozzles is guidable into the through holes and into the inside of the bearing. Thus, the nozzles and the through holes of the bearing ring may be aligned so that lubricant may be directly guided from the outside of the retainer, through the nozzles, through the through holes of the bearing ring and into the inside of the bearing.

[0025] According to a further embodiment, the cable groove comprises at least one circumferential groove on the circumferential surface of the bearing ring facing the retainer, wherein the at least one circumferential groove extends at least partially around the circumferential surface. In such a circumferential groove, a sensor (for example a fiber optic sensor in stripe or band form) and / or sensor cable may be arranged and may be guided along the circumference of the bearing ring. As the cable and / or sensor is arranged in the groove, there is enough space for the cable and / or sensor to be not damaged by the contact between the bearing ring and the retainer.

[0026] The circumferential groove may comprise at least one branching off arc-shaped groove particularly with a straight continuation to one of the front ends of the bearing ring. Using the arc-shaped groove and its continuation particularly somehow parallel to the alignment groove the cable and / or sensor may be guided from the circumference of the bearing ring to the outside and may then be coupled to a control or processing unit. Further preferred embodiments are defined in the dependent claims as well as in the description and the figures. Thereby, elements described or shown in combination with other elements may be present alone or in combination with other elements without departing from the scope of protection.

[0027] Brief description of the drawings

[0028] In the following, preferred embodiments of the invention are described in relation to the drawings, wherein the drawings are exemplarily only, and are not intended to limit the scope of protection. The scope of protection is defined by the accompanied claims, only.

[0029] The figures show:

[0030] Fig. 1 : a schematic perspective view of a bearing unit;

[0031] Fig. 2: a schematic perspective enlarged view of a bearing unit;

[0032] Fig. 3: a schematic plan view of a portion of a bearing unit;

[0033] Fig. 4: a schematic cross-sectional view of a portion of a bearing unit;

[0034] Fig. 5: a schematic plan view of a portion of a bearing unit; and

[0035] Fig. 6: a schematic plan view of a portion of a bearing unit.

[0036] Detailed description of the invention

[0037] In the following same or similar functioning elements are indicated with the same reference numerals.

[0038] Fig. 1 shows a bearing unit 1 which may be used in machine spindles or any other application. The bearing unit 1 comprises a bearing ring 2 and a retainer 4. In the embodiment shown in the figures, the bearing ring 2 is an outer ring and the retainer 4 is a sleeve. Alternatively, the retainer 4 could be a housing. Further, the bearing ring 2 could be an inner ring and / or the retainer 4 could be a shaft or housing.

[0039] In order to provide a proper alignment of the bearing ring 2 with respect to the retainer 4, the bearing ring 2 comprises a alignment groove 6, which has the form of a recess 6. The recess 6 extends axially from one front end of the bearing ring 2 to the other front end of the bearing ring 2. The retainer 4 comprises alignment elements 8. These alignment elements 8 are protrusion elements, which radially protrude from the retainer 4 in the direction of the bearing ring 2. The protrusion elements may be screwed into through holes 10 being formed in the retainer 4. The protruding portion of the protrusion elements 8 extends over the surface of the retainer 4 and engages with the recess 6 of the bearing ring 2. The combination of the protrusion elements 8 and the recess 6 provides an angular alignment of the bearing ring 2 with respect to the retainer 4. In addition, due to the engagement of recess 6 and protrusion elements 8, an anti-rotation functionality is provided so that the bearing ring 2 cannot rotate with respect to the retainer4.

[0040] The retainer 4 further comprises an abutment element 12. The abutment element 12 may be in the form of a flange as shown in Fig. 1. Alternatively, the abutment element 12 may consist of discrete elements (not shown). When the bearing ring 2 is slid into the retainer 4, the front end of the bearing ring 2 abuts against the abutment element 12 and is thus stopped in its axial movement.

[0041] Circumferentially extending grooves 14 are formed in the circumferential surface of the bearing ring 2. Further, axially extending grooves 16 may be formed in the circumferential surface of the bearing ring 2. Preferably, the circumferentially extending grooves 14 and the axially extending grooves 16 may be connected with each other. In these grooves, 14, 16, sensors, in particular sensors in band or stripe form, and / or sensor cables 20 may be arranged and may be guided around the circumference of the bearing ring 2. Further, the grooves 14 may comprise arc-shaped grooves 18 somehow connecting the circumferentially and axially extending grooves 14 and 16, among other things leading to the outside of the bearing ring 2 as also shown in Figs. 5 and 6 but also 1. In these grooves 18, the sensors and / or sensor cables 20 may be guided to the outside. Thereby the axially extending grooves 16 are essentially parallel to the axially extending recess 6 and are angularly distanced to each other e.g. of circa 25°. At least at the intersections respectively crossings of the recess 6 with the circumferentially extending grooves 14, the grooves 14 are deeper than the recess 6, particularly so that the depth of the recess 6 is less than the remaining groove depth of the groove 14 with the sensor cable 20 arranged in there.

[0042] The grooves 14, 16 and 18 may provide a grid of grooves so that the sensors and / or cables 20 may be arranged between the bearing ring 2 and the retainer 4 as needed. For example, the sensors and / or cables 20 may be guided to the outside at any side of the bearing ring 2 and at any angular position of the bearing ring 2.

[0043] As shown in Fig. 2, the through holes 10 may comprise threads into which the protrusion elements 8 may be screwed.

[0044] As shown in Figs. 2 and 3, in the recess 6, through holes 22 are formed. These through holes 22 serve as a connection between the outside of the bearing unit 1 and the inside of the bearing unit 1. As further shown in Fig. 4, the protrusion elements 8 comprise through holes 26. Lubricant may be guided through the through holes 22 and 26 to the inside of the bearing unit 1. A seal 24 is arranged at the junction of protrusion element 8 and bearing ring 2. The seal 24 reduces the risk of radial deformation of the bearing ring 2 when installing the protrusion element 8 and seals the contact between protrusion element 8 and bearing ring 2 to avoid leakage of lubricant.

[0045] In summary, the described bearing unit allows a proper alignment of the bearing ring with respect to the retainer and prevents the bearing ring to rotate with respect to the retainer while allowing lubrication of the bearing in the application. The bearing unit also enables to integrate and exit the bearing ring with little compromise of rigidity of the bearing arrangement.

[0046] Reference numerals

[0047] 1 bearing unit

[0048] 2 bearing ring

[0049] 4 retainer

[0050] 6 alignment groove / recess

[0051] 8 alignment element / protrusion element

[0052] 10 through hole

[0053] 12 abutment element

[0054] 14 groove

[0055] 16 groove

[0056] 18 groove

[0057] 20 cable

[0058] 22 through hole

[0059] 24 seal

[0060] 26 through hole

Claims

C l a i m s1. Raceway element of a rolling bearing with- a raceway side with at least one track for rolling-off of rolling bodies of the rolling bearing, and- an other side being different, particularly opposite to the raceway side with at least one cable groove, whereby the course of the cable groove on said side particularly corresponds at least in sections to the course of the track on the raceway side, and whereby at least one sensor cable particularly comprising an optical fiber with a Bragg grating is arranged in the cable groove particularly for at least a spatially resolved detection of mechanical strains, and with an alignment groove being designed to engage with an alignment element of a retainer, to which the raceway element is intended to be mounted, particularly for a defined angular positioning and / or an anti-rotation locking between the raceway element and the retainer, whereby at least the shapes and courses of the cable groove and the alignment groove are designed at least the way that any damage of the properly arranged sensor cable by the intended engagement of the alignment element is excluded.

2. Raceway element according to claim 1, whereby the cable groove and the alignment groove show an intersection, particularly approximately at a right angle, whereby the cable groove particularly is deeper than the alignment groove at least at the intersection, particularly so that the depth of the alignment groove is less than the remaining groove depth of the cable groove with the sensor cable arranged in there.

3. Raceway element according to claim 1 or 2, whereby the cable groove comprises an arclike branch that continues approximately in the direction of the alignment groove for feeding the sensor cable, whereby the continuation of the arc-like branch is particularly angularly distanced to the alignment groove by at least 15°.

4. Raceway element according to one of the claims 1 to 3, whereby the alignment groove comprises a lubrication through-hole penetrating the raceway element form the other to the raceway side for the transport of a lubricant towards the track.

5. Raceway element according to one of the claims 1 to 4, whereby the raceway element is ring-shaped and said raceway side and the other side are formed by the inner and outer jacket of the ring, the alignment groove follows an axial direction particularly along an entire axial length of the jacket, the cable groove extends at least in a circumferential direction and / or the continuation of the arc-like branch of the cable groove opens out into a side face of the ring-shaped raceway element.

6. Retainer, particularly a sleeve or a housing, to which the raceway element according to any of the preceding claims is or is intended to be mounted.

7. Retainer according to claim 6, whereby the alignment element is formed by at least one protrusion element which protrudes from the retainer in the direction towards the raceway element, and which is configured to engage with the alignment groove, whereby the protrusion element particularly projects from an inner jacket of the retainer in a radial direction towards an outer jacket of a ring-shaped raceway element.

8. Retainer according to claim 6 or 7, whereby the protrusion element is formed separately from the retainer and is inserted into a particularly radially extending hole within the retainer, whereby the protrusion element particularly is preloaded and compressed, particularly by a spring, during the mounting and / or in the mounted state.

9. Retainer according to one of the claim 6 to 8, whereby the protrusion element is formed as a lubricant nozzle being connectable to a lubricant supply system, whereby the alignment between the retainer and the raceway element is particularly designed so that the nozzle aligns with a lubrication through-hole penetrating the raceway element for the transport of a lubricant towards the track, whereby the nozzle particularly comprises a seal towards the alignment groove.

10. Retainer according to one of the claims 6 to 9, whereby the retainer comprises a stop determining together with the shape of the raceway element an additional orientation aspect between the raceway element and the retainer, particularly a stop in an axial direction of a ring-shaped raceway element.

Images