DE102009014239A1 - Apparatus for determining movement of rolling body of bearing, particularly roller bearing, has annular coil for detecting change in magnetic field of rolling body during rotation of body of rolling body - Google Patents

Abstract

The apparatus has a magnetic field fixed at the body of a rolling body (5), where an annular coil (12) detects a change in the magnetic field of the rolling body during the rotation of the body of the rolling body. The magnetic field is arranged substantially perpendicular to the intrinsic rotation axis (6) of the rolling body. An independent claim is also included for a method for determining the movement of a rolling body of a bearing, particularly roller bearing.

Description

Field of the invention

The The invention relates to a device and a method for detection the movement of a rolling element of a bearing, in particular a rolling bearing, and a bearing, in particular a rolling bearing, with such a device.

Out practice is known that rolling elements of a Bearings, especially a rolling bearing, during operation of the bearing have a slip, during movement of the rolling element along a raceway of the bearing the rotation of the rolling body changes about its own axis of rotation. It is known that the occurrence of slippage, for example, of the type of lubricant in the bearing or the load on the Bearings, especially the load direction of the bearing and the arrangement the load zone in the warehouse, can depend. A capture the rotation of one of the rolling bodies in operation The bearing is therefore desirable at least for evidence of slippage.

DE 20 25 693 A describes a method or device for detecting the rotational speed of a cage, not the rolling element guided in the cage itself, wherein on the rolling elements magnetic steel rivets are arranged which generate a magnetic field which is detected by a magnetic sensor as soon as the steel rivets the magnetic Sensor happen. A conclusion of the detected speed of the cage on the rotation of the individual rolling elements is not readily possible.

EP 0 395 783 A1 describes a method and apparatus for detecting the rotational speed of a cage in which magnetic rivets are arranged. Again, it is not easy to deduce the rotation of the rolling elements about the respective axis of rotation.

GB 1 509 170 A describes a device for detecting the rotational speed of a cage whose rolling elements consist of a magnetically active, in particular magnetizable material. The device comprises a pole shoe as a flux guide element, wherein the pole piece points in the direction of the raceway. The pole piece is surrounded by a coil in which a voltage is induced when one of the rolling elements passes the point at which the pole piece is arranged. The device allows counting how often a rolling element passes the pole piece and thus a conclusion on the cage speed. The device is only indirectly indicative of a slip of the rolling elements, for example in the event that all rolling elements slip, so that the speed of the cage is massively affected, or in the event that averaged over all rolling elements slip affects the movement of the cage. A precise detection of the movement, in particular the rotation of a particular, picked out rolling element, is not possible.

Object of the invention

It The object of the invention is a device or a method for detecting the movement, in particular the rotational movement, a Rolling elements of a bearing about the axis of rotation specify the rolling element, so that the internal rotation in particular also easy to detect for full complement rolling bearings is.

Summary of the invention

These Object is according to the invention with a device according to claim 1 and by a method according to claim 9 for a bearing solved according to claim 10.

The firmly connected to the body of the rolling element Magnetic field increases with the movement of the rolling element, in particular to the rotational movement of the rolling body about its own axis of rotation, part, with a time-varying Magnetic field is created, detects the change in the toroidal coil becomes.

The Device requires only a minor intervention on one of the several rolling elements and leaves the kinematic Properties of the remaining rolling elements, also of the rolling element provided with the magnetic field, and the camp as a whole largely unaffected.

The Device is inexpensive and can, if necessary, in the case the damage analysis, in addition to a in division of labor installed bearing and removed again.

The Device is also for full complement bearings suitable, which have no cage, the rolling elements leads. The device is further independent of the type of rolling elements and thus for Cylindrical, barrel or conical rolling elements equally suitable. Another advantage is that the measurement result, that is, the voltage induced in the toroid, is led directly to the outside to the camp and there can be tapped as a voltage signal, so that a transmission the measurement result within the camp, for example via a arranged on the cage telemetry system, omitted.

Accordingly, the method provides that the magnetic field is provided on the body of the rolling body, and that then the change of the magnetic field in the rotation of the body of the rolling body about its axis of rotation by means of a Coil, for example, the toroidal coil is detected.

Of the the magnetic field having rolling elements and the Ring coils can be kept independent of a warehouse be installed in the bearing for measurement purposes only. It but it is understood that the rolling element having the magnetic field and the toroidal coil are permanently arranged in a warehouse, for example at a retraction of the warehouse or at a damage analysis.

Preferably is provided that the magnetic field is substantially perpendicular to arranged the axis of rotation of the rolling body is. Here, the toroidal coil is arranged substantially in the plane, within which the two or more poles of the magnetic field rotate, allowing a change of magnetic field during rotation of the rolling body about its own axis of rotation particularly strong and reliably detectable voltage induced in the toroidal coil.

Preferably is provided that the magnetic field through a permanent magnet is formed, which on the body of the rolling element is attached. Such a permanent magnet can be easily retrofitted, especially in an already in Install bearing in operating position. The permanent magnet is structurally made of the actual body of the rolling element and attached to the body of the rolling element, for example by means of a screw connection, which is a subsequent Removing the permanent magnet allows.

Regarding the formation of the magnetic field by a on the body of the rolling body additionally attached permanent magnets is preferred provided that the permanent magnet formed as a bar magnet is. A bar magnet can be designed so that the magnetic field forming poles arranged at the two ends of the bar magnet are such that upon rotation of the rolling element and thus the bar magnet depending one of the two poles of the toroidal coil comes close. It is further understood that two or more magnetic pole pairs can form the magnetic field on the rolling element, wherein each two adjacent magnetic poles of the two or more pairs of magnetic poles enclose a constant angle with each other form a multipolar magnetic field.

alternative to a bar magnet can also be a flat, permanent magnet be provided cylindrical disc, wherein at the two end faces the disc formed at least one north or south pole is. Again alternatively, as a permanent magnet, a flat cylindrical Was provided disc, wherein at one of the two end faces of the Disc extending in the circumferential direction of the disc sequence is formed by north and south poles. Again, alternatively this can be provided as a permanent magnet, a flat cylindrical disc be, wherein at both end faces one each in the circumferential direction the disk extending sequence of north and south poles is provided, and wherein a magnetic pole on the first end face an unlike pole on the second face opposite.

alternative to the formation of the permanent magnet by a bar magnet or by a flat, cylindrical solid disk, the permanent magnet by a flat ring or by a flat, hohlzylindri cal Be formed on the disc, being on the outside Lateral surface of the ring or the hollow cylindrical disc in the circumferential direction at least one north pole and at least one south pole are provided. Particularly preferred is one in the circumferential direction proceeding sequence of several poles.

Regarding the formation of the magnetic field by a on the body of the rolling body fixed permanent magnets is preferably provided that the permanent magnet as a multi-pole magnetic disk, in particular as Encoder ring, is formed. The multi-pole magnetic disk has two or more, formed at its periphery magnetic poles and can be used as a magnetic disc on a face fasten the rolling element. In comparison to one Bar magnet with two magnetic poles allows the Magnetic disc a finer temporal resolution of rotation of the rolling body about its own axis of rotation, as ever two adjacent poles provide a signal, so the full Rotation of the rolling element with a variety of Signals is encoded. Suitable magnetic disks are as encoder rings available.

Regarding the formation of the magnetic field is preferably provided that imprinted the magnetic field in the body of the rolling body is, so that an additional element attached to the body must be fixed, becomes unnecessary. With that the kinematic properties of the magnetic field Rolling elements not influenced, in particular in high-speed bearings or in small-sized rolling elements is advantageous. The magnetic field can be achieved by means of a pulsed current supply be imprinted on the body of the rolling element, provided the material of the body of the rolling element is magnetizable and electrically conductive.

Preferably, the device further comprises a magnetic switch which is arranged on the circumference of the raceway, and which detects the passage of the magnetic field of the rolling body. This can be in addition to the speed of the rolling element also detect at which point be the rolling elements be place. It can be seen, for example, to what extent the rotational speed of the rolling element changes when it enters the load zone of the bearing when the magnetic switch is arranged close to the load zone.

Preferably is provided with regard to the design of the magnetic switch, that the magnetic switch a magnetic field sensor (for example a Hall sensor or a magnetoresistive sensor), an inductive Sensor or a reed contact. The reed contact has one electrical conductive contact, which is closed when a Magnetic field of sufficient strength is present, and at Absence of the magnetic field can reopen.

Further Advantages and features of the invention will become apparent from the dependent Claims and from the description of an embodiment.

The Invention will be described in the following with reference to the appended Drawing described and explained in detail.

Short description of the drawing

1 shows a detail of a cross section of an embodiment of a device according to the invention, an embodiment of a bearing according to the invention and a sub-step in an exemplary implementation of the method according to the invention.

Detailed description the drawing

1 shows a detail of a camp 1 that has a first bearing ring 3 and a second bearing ring 2 having. The first bearing ring 3 is as outer ring of the bearing 1 formed and with respect to the second bearing ring 2 , which is formed as an inner ring, fixed. At a career 4 of the outer ring 3 Run from rolling elements, wherein the rolling elements shown one 5 has a magnetic field.

The rolling element 5 essentially moves around its own axis of rotation 6 rotatable along the closed track 4 of the outer ring 3 as well as another closed career 7 of the inner ring, leaving the bearing 1 is designed as a rolling bearing. The rolling element 5 has a substantially cylindrical body. The rotation axis 6 of the rolling element 5 defines a pitch circle of the rolling bearing, which is substantially in the middle between the two raceways 4 . 7 is arranged.

With the body of the rolling element 5 a magnetic field is firmly connected, so that during the rotation of the rolling element 5 around the self-rotation axis 6 The magnetic field rotates while the direction of the magnetic field is variable over time.

The magnetic field is through a permanent magnet 8th formed on the body of the rolling element 5 is attached. The bar magnet 8th has a north and a south pole, wherein at one pole, the magnetic field from the bar magnet 8th from and to the other pole back in the bar magnet 8th entry. The magnetic field is at an angle, substantially at a right angle, to the axis of self-rotation 6 of the rolling element 5 , The permanent magnet 8th is designed as a bar magnet, the rotationally fixed to the body of the rolling element 5 in a related to the axis of rotation 6 axial distance to an end face 9 the body of the rolling element 5 is attached by means of a screw connection.

The screw connection comprises a screw 10 , whose external thread in a in the body of the rolling element 5 at the end face 9 trained internal thread engages, the screw axis with the axis of rotation 6 is formed in alignment. The screw 10 includes an intermediate piece 11 on the front 9 of the rolling element 5 rests and on the bar magnet 8th is arranged so that the bar magnet 8th from the metallic body of the rolling element 5 is kept at a distance.

Rotationally fixed to the outer ring 3 and thus with respect to the rotating rolling elements 5 stationary is a toroidal coil 12 arranged, the coil axis with the axis of rotation of the inner ring, not shown 2 of the rolling bearing 1 flees. Around this axis of rotation of the bearing 1 is the toroidal coil 12 arranged concentrically, so runs relative to the two raceways 4 . 7 parallel to these, albeit offset in the radial and axial directions. The toroidal coil 12 comprises a plurality of windings of a copper conductor, which rotate around the axis of rotation or the coil axis multiple times and at the ends, not shown, the voltage can be tapped, in the toroidal coil 12 is induced when the ring coil 12 passing magnetic flux changes.

Such a change in the magnetic flux occurs, for example, when that with the rolling elements 5 connected, by the bar magnet 8th caused magnetic field with the rolling elements 5 rotates, in particular areas of the magnetic field of the bar magnet 8th outside of the ring coil 12 bordered area and thus to the ring coil 12 permeating magnetic flux no longer contribute.

To detect the temporal change of the magnetic field of the permanent magnet 8th To facilitate, is the toroidal coil 12 in the radial direction be pulled on the pitch circle with its own axis of rotation 6 arranged outside, in the direction of the axis of rotation 6 slightly axially from the permanent magnet 8th staggered. In the area of the toroidal coil 12 The field lines of the magnetic field curve to the one magnetic pole at one of the two ends of the bar magnet 8th , so that here is a strong gradient of the magnetic field during the rotation of the bar magnet 8th around the self-rotation axis 6 of the rolling element 5 arises.

The toroidal coil 12 is in a recording 13 arranged, which consists of a non-magnetic material such as plastic and by means of which the toroidal coil 12 on the outer ring 3 is releasably fixed.

The recording 13 with the toroidal coil 12 as well as the permanent magnet 8th with the screw 10 are from the camp 1 independently manufactured and subsequently to the outer ring 3 of the camp 1 or to the body of the rolling element 5 attached to the internal rotation of the rolling element 5 along the entire career 4 . 7 to be able to capture. To carry out the method described above, the rolling elements 5 by the attachment of the permanent magnet 8th on the body of the rolling element 5 provided with the magnetic field. In the further implementation of the method then becomes the case of the rotation of the rolling body 5 around its own axis of rotation 6 time-varying magnetic field by means of the coil, especially the toroidal coil 12 , detected.

The rolling element rotates 5 with a constant rotational speed about the axis of rotation 6 , is in the ring coil 12 induces a voltage which substantially corresponds to a sinusoid, wherein a zero crossing of the sine curve of half a revolution of the rolling body 5 equivalent. From the period of the sinusoid then the speed of the rolling element can be 5 around the self-rotation axis 6 determine. Stops the rotation of the rolling element 5 around the self-rotation axis 6 , the magnetic flux remains through the toroidal coil 12 essentially constant and it is in the toroidal coil 12 no voltage induced. Starts the rolling element 5 with the rotation about the axis of rotation 6 , a voltage in the toroidal coil 12 induced, whose amplitude and period increases. With the device described above can be determined in particular whether the designated with the magnetic field rolling elements 5 during one entire round along the raceways 4 . 7 a constant rotational speed about the axis of rotation 6 having. Furthermore, it can be determined under which conditions the rotation of the rolling element 5 around the self-rotation axis 6 slows or stops, so that a slip of the rolling element 5 becomes detectable.

In the embodiment described above, the magnetic field was on the rolling element 5 by a single bar magnet 8th designed as a permanent magnet. It is understood that the magnetic field can also be formed by solid or hollow cylindrical, thin disc-shaped permanent magnets, wherein at least one magnetic pole of at least one pair of magnetic poles is formed on the end faces or on the lateral surfaces of the discs, so that a magnetic field is created which exceeds having a pole pair. It is further understood that the magnetic field can also be formed by a solid or hollow cylindrical thin disk with two or more poles of unlike poles, wherein the disk on the end face 9 of the rolling element 5 is fixed, for example, solely by magnetic forces between the disc and the body of the rolling element 5 so that the screw connection can be omitted. The connection of the permanent magnet to the rolling elements 5 can also be made by gluing or pressing. If the magnet is embedded directly in the end face of the rolling element, a magnetic insulation must be provided so that the magnetic field in the direction of the toroidal coil 12 can train.

The invention has been described above with reference to an embodiment in which the rolling elements 5 a cylindrical shape with the axis of rotation 6 had. It is understood that the rolling element is also another, about an axis of rotation 6 can have rotationally symmetrical shape.

The invention has been described above with reference to an embodiment in which the toroidal coil 12 in the recording 13 on the outer ring 3 , So based on the by the rotation axis 6 circumscribed circle radially outboard, was arranged. It is understood that the toroidal coil 12 also on a bearing receiver, on which the outer ring 3 rotatably received, can be arranged. It goes without saying that the toroidal coil 12 also on the inner ring 2 , in particular with respect to the pitch radially inwardly disposed, may be arranged.

1

camp

2

second bearing ring

3

first bearing ring

4

career

5

rolling elements

6

Autorotation axis

7

career

8th

permanent magnet

9

face

10

screw

11

connecting piece

12

toroid

13

admission

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 2025693 A [0003]
• EP 0395783 A1 [0004]
• GB 1509170 A [0005]

Claims (11)

Device for detecting the movement of a rolling element of a bearing ( 1 ), in particular a rolling bearing, wherein the rolling elements ( 5 ) about an axis of rotation ( 6 ) rotatable along a closed track ( 4 . 7 ) of the warehouse ( 1 ), the device comprising: a with the body of the rolling element ( 5 ) fixed magnetic field, and a toroidal coil ( 12 ), which is a change of the magnetic field of the rolling element ( 5 ) during the rotation of the body of the rolling element ( 5 ) detected. Apparatus according to claim 1, characterized in that the magnetic field substantially perpendicular to the axis of rotation ( 6 ) of the rolling element ( 5 ) is arranged. Apparatus according to claim 1 or 2, characterized in that the magnetic field by a permanent magnet ( 8th ) is formed on the body of the rolling body ( 5 ) is attached. Device according to claim 3, characterized in that the permanent magnet ( 8th ) is designed as a bar magnet. Device according to claim 3, characterized in that that the permanent magnet as a multi-pole magnetic disc, in particular as an encoder ring is formed. Apparatus according to claim 3, characterized in that the magnetic field in the body of the rolling body ( 5 ) is imprinted. Device according to one of claims 1 to 6, further comprising a magnetic switch disposed on the periphery the track is arranged, and the passing of the magnetic field of the rolling body detected. Device according to claim 7, characterized in that that the magnetic switch has a Hall sensor, a magnetoresistive Sensor, an inductive sensor or a reed contact. Method for detecting the movement of a rolling element ( 5 ) of a warehouse ( 1 ), in particular a rolling bearing, wherein the rolling elements ( 5 ) about an axis of rotation ( 6 ) rotatable along a closed track ( 4 . 7 ) of the warehouse ( 1 ), the method comprising the steps of: providing a magnetic field to the body of the rolling element ( 5 ), and detecting a change in the magnetic field during the rotation of the body of the rolling body ( 5 ) about its own axis of rotation ( 6 ) by means of a coil ( 12 ). Bearings, in particular rolling bearings, comprising a Device according to one of claims 1 to 8. Bearing according to claim 10, characterized in that the coil ( 12 ) on a bearing ring ( 3 ) is fastened, along its career ( 4 ) of the rolling elements ( 5 ) moves.