Rolling bearing with measuring roller

Abstract

The invention relates to a rolling bearing comprising a first bearing ring, a second bearing ring which is rotatably arranged relative to the first bearing ring, and at least one row of axially symmetric rolling bodies (5) which have at least one end face (7), the rolling bodies (5) of the row of rolling bodies being arranged between the bearing rings in a load direction (L) so as to be rollable in order to transmit a force, the invention relates to a measuring roller (6) comprising a rolling body (5) and a cage pocket (7) arranged on the rolling body (5) and accommodated at a distance from each other by the cage in the cage pocket, a generator pole piece (11) being arranged on the end face (7) of the rolling body (5) designed as the measuring roller (6), the generator pole piece supporting a plurality of coils (12) arranged on a circular path (K) coaxial to the rolling body axis (A), the invention relates to a cage for a motor vehicle, in particular for a motor vehicle, comprising a circular track (K) and a plurality of cage pockets (13) arranged in the circular track (K) and interacting with magnet holders (13), which are fixed opposite each other in the corresponding cage pockets and which support a plurality of magnets (14), the magnets (14) being strip-shaped, the strip-shaped magnets (14) extending in the load direction (L) and partially covering the circular track (K).

Description

Technical Field

[0001] The invention relates to a rolling bearing having rolling elements designed as measuring rollers according to the preamble of claim 1 . Background Art

[0002] Rolling bearings, in particular large rolling bearings, are known from the prior art, which have at least one rolling element designed as a measuring roller. The measuring roller serves to record and store data in the interior of the bearing during operation of the rolling bearing, or to transmit the data wirelessly to the outside. In this way, for example, data about the current load, temperature, rotational speed, position of the rolling bearing and / or slippage of the measuring roller can be detected. In order to perform its tasks, the measuring roller requires electrical energy. The energy can be stored in the measuring roller, for example, by means of a battery, but the capacity of the battery limits the time for which the measuring roller remains functional.

[0003] In order to eliminate this disadvantage, autonomous energy supply has already been proposed in the prior art, the electrical energy being generated by the relative movement between the measuring roller and the cage pocket surrounding the measuring roller.

[0004] For example, DE 698 28 236 T2 discloses a rolling bearing with rolling elements having a cylindrical bore in which an electric energy generator is arranged. The electric energy generator is a dynamometric generator or a Hertz ring and is connected to a rolling element cage located outside the rolling elements via an elastic clutch component. The generator in the rolling element bore is driven by a reduction gear mechanism connected to the elastic clutch component. The disadvantage is that the rolling element contains a plurality of movable parts and a mechanical connection to the cage is necessary in order to drive the generator. Both are potentially prone to failure, wherein damage to the elastic clutch can even lead to the presence of foreign matter in the raceway system of the bearing, which can affect the function of the entire rolling bearing.

[0005] Thus, DE 11 2013 007 412 T5 describes a sensor roller, the energy generation of which is based on a contactless inductive interaction between a sensor roller and a cage. The sensor roller has a bore for accommodating a sensor unit and a first part of a generator assembly. The second part of the generator assembly is provided by the cage, wherein at least one magnetic circuit is opened and closed as a function of a relative rotation between the cage and the sensor roller. The second part of the generator assembly comprises two permanent magnets, which are connected by a metal plate with a high magnetic flux ratio. The magnetization directions of the permanent magnets are identical and are oriented axially with respect to the rotation axis of the sensor roller. The limitations are given by the maximum degree of miniaturization of the generator assembly to be mounted in the bore of the rolling roller and the amount of power to be generated at a certain rotation speed.

[0006] DE 10 2016 116 118 A1 describes a measuring roller with a microgenerator having an increased power output. For this purpose, a plurality of coils arranged on a circular track are provided, which are arranged radially on the measuring roller between the central hole of the measuring roller and its outer circumference. For example, at the location of the measuring roller, the cage includes four magnets, which allow the microgenerator to induce an electric current.

[0007] However, these solutions known from the prior art have not proven to be particularly reliable. It has been found that, in particular when the load on the rolling bearing is increased due to tilting moments, the known induction generators generally only provide significantly reduced electrical energy. Summary of the invention

[0008] The object of the present invention is to provide a rolling bearing with a measuring roller which ensures a particularly reliable energy supply to the measuring roller in all load situations of the rolling bearing, without requiring movable parts to be provided in the measuring roller.

[0009] This object is achieved by a rolling bearing having the features of claim 1 .

[0010] A rolling bearing is thus provided, which comprises a first bearing ring, a second bearing ring rotatably arranged relative to the first bearing ring, and at least one row of axisymmetric rolling bodies. The axisymmetric rolling bodies have at least one end side. The rolling bodies of the rolling body row are arranged rollably between the bearing rings in the load direction for the purpose of transmitting force and are accommodated in cage pockets spaced apart from one another by a cage. A generator pole piece is arranged on the end side of the rolling body configured as a measuring roller, which supports a plurality of coils arranged on a circular track coaxial with the axis of the rolling body. The generator pole piece cooperates with a magnet holder fixed oppositely in the corresponding cage pocket, which supports a plurality of magnets. The magnet is configured as a bar, which extends in the load direction and partially covers the circular track.

[0011] The invention is based on the recognition that the load conditions of rolling bearings can lead to deformations of the rolling bearing rings during operation, which deformations have a negative effect on the energy acquisition of the measuring roller. In particular, in the case of non-uniform loads on the circumference of the rolling bearing rings, such as tilting moments, local displacements of sections of the rings in the load direction can result, which are transmitted by the rolling elements between the bearing rings. In contrast, the cage, which is inserted into the raceway system with a certain clearance, is subject to only a small deformation compared to the bearing rings, resulting in a relative movement between the rolling elements and the cage in the load direction. This relative movement reduces the energy yield of the induction generator known from the prior art, because the coil loses its orientation relative to the magnet and the magnetic flux passing through the coil is correspondingly greatly reduced. In the measuring rollers known from the prior art, displacements of a few millimeters can lead to a collapse of the energy supply.

[0012] According to the invention, the relative movement between the cage and the rolling elements is compensated by the strip-shaped extension of the magnets in the load direction. Thus, even in the case of relative movement between the cage and the measuring roller, the coils supported by the generator pole pieces remain arranged opposite the respective magnets, so that the magnetic flux through the coils remains available even in the case of relative movement.

[0013] In a preferred embodiment, the magnets arranged adjacent to one another along the circular track are polarized in opposite directions in the direction of the rolling element axis. The energy yield is increased by the change in polarization direction between all adjacent magnets, since an induced voltage is generated in each coil that is transferred from the field of one magnet to the field of an adjacent magnet along the circular track when the measuring roller rotates. However, configurations are also conceivable in which the polarization of the magnets changes at greater intervals, i.e., for example, two identically polarized magnets are arranged one after another along the circular track.

[0014] In another preferred embodiment of the present invention, the coils supported by the generator pole pieces are connected in series, wherein adjacent coils have opposite winding directions. The series connection of the coils allows a simple connection of the generator, wherein the respectively alternating winding directions of the coils ensure that the induced voltage pulses are added in the same direction.

[0015] Furthermore, it is preferred that the bar magnet has a width transversely to the load direction that is at least as large as the inner diameter of the coil. The inner diameter of the coil determines the region of the generator pole piece that is sensitive to the magnetic flux. In order to ensure the greatest possible energy yield, it is advantageous if this region is at least temporarily completely covered by the width of the bar magnet.

[0016] Advantageously, the majority of the bar magnets have a length in the load direction of at least twice the outer diameter of the coil. This extension of the magnets ensures adequate compensation for relative movements between cage and rolling element in the load direction. In particular, it has proven sufficient if the majority of the magnets also guarantee partial coverage of the circular track under load. If, for manufacturing reasons, not all magnets can be designed with the same length, this generally has only a minor effect on the power supply of the measuring roller.

[0017] Preferably, the number of coils corresponds to the number of bar magnets. Thus, during the movement of each coil on the circular track, there is exactly one magnet corresponding to each coil at each moment, thereby further improving the energy yield. Preferably, at least six coils are arranged on the circular track.

[0018] The magnet holder is preferably made of a material with a magnetic permeability of less than 2, preferably less than 1.5, and particularly preferably less than 1.1. The magnetic permeability of the material is determined at a typical reference magnetic field strength of 8000 A / m (= about 100 Oe). It has been shown that materials with a higher magnetic permeability lead to at least partial short-circuiting of the magnetic field lines inside the magnet holder. As a result, this part of the magnetic flux provided by the magnet is no longer used for inductive energy generation and leads to a significant reduction in energy production. The lower the magnetic permeability of the material of the magnet holder, the greater the part of the magnetic flux of the magnet that can be used for energy generation, thereby increasing the efficiency of energy generation.

[0019] Preferably, the magnet holder is made of austenitic steel or bronze. Due to its metallographic structure, austenitic steel has a very low magnetic permeability of close to 1 compared to ferrite or martensitic steel. Austenitic steel and bronze thus combine the advantageous properties of low magnetic permeability and high mechanical load capacity and are therefore suitable for absorbing mechanical loads on the rolling element cage over a long service life. However, in principle, it is also conceivable to make the magnet holder from other materials, for example from high-strength plastics, such as PEEK (polyetheretherketone).

[0020] In a preferred embodiment, the magnet holder is welded to the cage. Welding provides a secure connection of the magnet holder to the cage without the use of additional fasteners. In this way, it is ensured that the magnet holder remains in the cage pocket over a long service life and that neither the fastener nor the magnet holder itself can loosen and enter the raceway system of the rolling bearing. However, other types of fastening for the magnet holder are also conceivable, such as a threaded connection or an adhesive connection.

[0021] Preferably, the bar magnets are held in the magnet holder separated from one another by webs that are parallel to one another. The webs also contribute to the separation of the magnetic flux between adjacent magnets and thus increase the energy yield.

[0022] Finally, it is advantageous to design the bar magnets to be of equal width or, in order to make the arc lengths of the respectively covered sections of the circular track uniform, to design them to be of different widths. Magnets of equal width allow the use of standard components, such as rectangular magnets. On the other hand, the advantage of making the covered arc length uniform by magnets of different widths is that the voltage pulses induced in the coils are added in a phase-synchronous manner, which contributes to a higher energy yield.

[0023] Further advantageous embodiments can be gathered from the following description and the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention is explained in more detail below with reference to an exemplary embodiment shown in the drawings.

[0025] Figure 1 An embodiment of a rolling bearing according to the invention is schematically shown in a partially sectional detail view, the rolling bearing having rolling elements configured as measuring rollers,

[0026] Figure 2 Schematically shows the Figure 1 a three-dimensional image of a rolling element designed as a measuring roller, which rolling element is accommodated in a cage pocket of a rolling element cage having a magnetic retaining element,

[0027] Figure 3A Schematically shows the Figure 2 a three-dimensional illustration of an arrangement of a measuring roller and a magnet holder, wherein the magnet holder is only partially filled with bar magnets,

[0028] Figure 3B and Figure 3C Schematic diagram showing the rolling bearing without load and with load, without magnets Figure 3A The layout, and

[0029] Figure 4 The arrangement of the measuring roller and the magnet holder according to the second embodiment is schematically shown in an end view from above. DETAILED DESCRIPTION

[0030] In the various figures, identical components are always provided with the same reference symbols and are therefore usually also each named or mentioned only once.

[0031] exist Figure 1 , a partial cross-sectional detail view of a rolling bearing 1 according to the invention is shown. The rolling bearing 1 comprises a first bearing ring 2, a second bearing ring 3 rotatably arranged relative to the first bearing ring 2, and a row 4 of axially symmetrical rolling elements 5.

[0032] In the exemplary embodiment shown, the rolling elements 5 are cylindrical rollers and have two end faces 7. The rolling elements 5 of the rolling element row 4 are arranged rollably between the bearing rings 2, 3 for force transmission in a load direction L. The rolling elements 5 are accommodated by a cage 8 in cage pockets 9, 10 at a distance from one another.

[0033] On one of the end faces 7 of the rolling element 5 designed as a measuring roller 6, a generator pole piece 11 is arranged, which carries a plurality of coils 12 arranged on a circular track K coaxial with the rolling element axis A (see Figure 3A ). The generator pole piece 11 cooperates with a magnet holder 13 fixed oppositely in a corresponding cage pocket 10, and the magnet holder 13 supports a plurality of magnets 14. The magnets 14 are configured as bars. The bar magnets 14 extend in the load direction L and partially cover the circular track K respectively.

[0034] The magnet holder 13 with the bar magnets 14 cooperates with the coil 12 supported by the generator pole piece 11 to form an induction generator.

[0035] Permanent magnets, in particular rare earth magnets such as neodymium magnets, are preferably used as bar magnets 14 .

[0036] Figure 2 A detailed view of a measuring roller 6 accommodated in a cage pocket 10 is shown. A magnet holder 13 is fixed in the cage pocket 10 opposite the end face 7 of the measuring roller 6. For this purpose, the magnet holder 13 is preferably inserted into a pocket-side recess 16 of the cage 8 and is particularly preferably adhesively bonded therein.

[0037] In the circumferential direction of the rolling bearing, the measuring roller 6 is accommodated in the cage pocket 10 with a small gap between the two partition walls 17 of the cage. Through this form fit, the generator pole piece 11 arranged on the end side of the measuring roller 6 is effectively prevented from being relatively displaced relative to the magnet holder 13 along the circumferential direction of the rolling bearing 1. However, depending on the load condition of the rolling bearing, the generator pole piece 11 may be relatively displaced relative to the magnet holder 13 along the load direction L.

[0038] Figure 3A The arrangement of the measuring roller 6 and the magnet holder 13 is shown in a three-dimensional end view. The magnet holder 13 is only filled with bar magnets 14 in the left half. In the right half, the bar magnets have been removed for a better overview so that the coils 12 and the generator pole pieces 11 located behind them can be seen. In the normal operating state of the rolling bearing 1, the magnet holder 13 is completely filled with magnets 14. Figure 3B and Figure 3C In order to further simplify the illustration, all magnets 14 are removed.

[0039] Figure 3A and Figure 3B The measuring rollers 6 and the cage 8 are shown in the unloaded state of the rolling bearing 1. In the unloaded state, the rolling element axis A passes through the magnet holder 13 in the central region between the bar magnets 14. On the other hand, in the loaded state, the rolling element axis A passes through the magnet holder 13 at a displaced, eccentric position in the load direction L.

[0040] As in FIG. 3A to FIG. 3C As shown in FIG. 1 , it is advantageous if exactly one bar magnet 14 is provided for each coil 12. In such a configuration, the number of coils 12 corresponds to the number of bar magnets 14. Thus, during the rolling movement of the measuring roller 6, each coil 12 corresponds to one of the magnets 14 and is penetrated by its magnetic field. Preferably, at least six coils 12, for example ten coils 12, are provided. FIG. 3A to FIG. 3C As shown in FIG. 1 , it is arranged on a circular track K.

[0041] The magnets 14 arranged along the circular track K are preferably polarized in the direction of the rolling element axis A. Particularly preferably, the magnets 14 arranged adjacent to each other are polarized in opposite directions. It is also preferred that the coils 12 supported by the generator pole pieces 11 are connected in series, wherein the adjacent coils 12 each have opposite winding directions. In this configuration, the magnetic field lines of each magnet 14 extend on the rolling element side through the interior of the coil 12 currently associated with the magnet 14, through the generator pole piece 11, the interior of the adjacent coil 12, and the adjacent magnet 14, and close in the material of the cage 8 on the side of the magnet holder 13 facing away from the rolling element 5. When the coil 12 moves through the magnetic field of the magnet 14, the field direction inside the coil changes respectively, whereby phase-correct voltage pulses are generated in all coils 12.

[0042] Preferably, the magnet holder 13 is made of a material with a magnetic permeability of less than 2, in particular less than 1.5, and particularly preferably less than 1.1, in order to avoid short-circuiting of magnetic field lines in the magnet holder 13. The magnet holder 13 can be made of austenitic steel or bronze, for example, and / or welded to the holder 8.

[0043] exist Figure 4 2 shows a second exemplary embodiment of the arrangement of measuring roller 6 and magnet holder 13 according to the invention, in which further geometric dimensions are indicated.

[0044] In order to ensure that the coil 12 is covered as completely as possible by the magnetic field of the bar magnet 14, the bar magnet 14 preferably has a width B transversely to the load direction L, which is at least as large as the inner diameter d of the coil 12. This ensures that the coil 12 achieves the greatest possible geometric coverage with the magnet 14 during its movement on the circular track K, thereby increasing the energy yield.

[0045] Furthermore, it is advantageous if the majority of the bar magnets 14 have a length l in the load direction L which is at least twice as large as the outer diameter D of the coil 12. The length l of the magnets 14 determines the maximum tolerance of the generator with respect to the relative displacement between the measuring roller 6 and the magnet holder 13 in the load direction L. The tolerance is sufficient if the majority of the coils 12 also remain arranged relative to one of the magnets 14 under load. In particular, the majority of the magnets 14 preferably have a length l of at least 2 cm, particularly preferably at least 3 cm.

[0046] The above implementation scheme is also applicable to FIG. 3A to FIG. 3C , even though the width and length of the magnet 14 are not individually indicated there. Since the height of the magnet holder in the load direction L is limited by the height of the holder 8 (see Figure 2 ), it may be necessary to specifically configure the middle magnet 14 to have a smaller length l so as not to exceed the maximum overall height of the magnet holder 13 (see FIG. 3A to FIG. 3C ). Depending on how the rolling bearing is constructed, it may also be necessary to arrange the magnets asymmetrically in order to be able to maintain the dimensions of the magnet holder given by the dimensions of the cage (not shown).

[0047] According to FIG. 3A to FIG. 3C The embodiments are different, in accordance with Figure 4 In the embodiment of the invention, the bar magnets 14 are not designed with equal width, but are designed with different widths in order to make the arc lengths b1, b2 of the respectively covered sections of the circular track K uniform. By making the arc lengths b1, b2 uniform, the switching of the coils 12 between adjacent magnets 14 can be better synchronized during the rolling motion, which allows the induced voltage pulses to be added in a phase-synchronous manner.

[0048] As per Figure 4 As shown in the embodiment of FIG. 1 , the bar magnet 14 can be designed in particular as a rectangle, a parallelogram or a trapezoid.

[0049] Another difference from the first embodiment is that, according to Figure 4 In the embodiment of FIG. 1 , only eight coils 12 are arranged on the circular track K.

[0050] In addition, Figure 1 The embodiments shown in the exemplary embodiment of FIG. 3 apply accordingly to the embodiment according to Figure 4 Embodiment of the invention.

[0051] Description of Reference Numerals

[0052] 1 Rolling bearings

[0053] 2 First bearing ring

[0054] 3 Second bearing ring

[0055] 4 rolling element rows

[0056] 5 Rolling elements

[0057] 6 Measuring roller

[0058] 7 End side

[0059] 8 Cage

[0060] 9, 10 cage pockets

[0061] 11 Generator pole piece

[0062] 12 Coil

[0063] 13 Magnet holder

[0064] 14 Magnet

[0065] 15. Splice

[0066] 16 recess

[0067] 17 Divider Wall

[0068] A Rolling element axis

[0069] b1, b2 arc length

[0070] B Width of bar magnet

[0071] d Inner diameter of the coil

[0072] D Coil outer diameter

[0073] K Circular track

[0074] l Length of bar magnet

[0075] L Load direction

Claims

1. A rolling bearing comprising a first bearing ring (2), a second bearing ring (3) arranged rotatably relative to the first bearing ring (2), and at least one row (4) of axisymmetric rolling bodies (5), the rolling bodies having at least one end side (7), wherein: The rolling bodies (5) of the rolling body row (4) are arranged between the bearing rings (2, 3) in a rollable manner along the load direction (L) for the purpose of transmitting force and are accommodated in cage pockets (9, 10) spaced apart from each other by a cage (8), wherein a generator pole piece (11) is arranged on the end side (7) of the rolling body (5) configured as a measuring roller (6), the generator pole piece supporting a plurality of coils (12) arranged on a circular track (K) coaxial with the rolling body axis (A) and cooperating with a magnet holder (13) fixed oppositely in the corresponding cage pocket (10), the magnet holder supporting a plurality of magnets (14), characterized in that the magnets (14) are strip-shaped, wherein the strip-shaped magnets (14) extend in the load direction (L) and partially cover the circular track (K).

2. The rolling bearing according to claim 1, characterized in that: The magnets (14) arranged adjacent to one another along the circular track (K) are polarized oppositely in the direction of the rolling element axis (A).

3. The rolling bearing according to claim 1 or 2, characterized in that: The coils (12) supported by the generator pole pieces (11) are connected in series, wherein the coils (12) adjacent to each other have opposite winding directions.

4. The rolling bearing according to any one of claims 1 to 3, characterized in that The bar-shaped magnet (14) has a width (B) transversely to the load direction (L) which is at least as large as the inner diameter (d) of the coil (12).

5. The rolling bearing according to any one of claims 1 to 4, characterized in that Most of the bar-shaped magnets (14) have a length (l) in the load direction (L) that is at least twice as large as the outer diameter (D) of the coil (12).

6. The rolling bearing according to any one of claims 1 to 5, characterized in that The number of coils (12) corresponds to the number of bar-shaped magnets (14).

7. The rolling bearing according to any one of claims 1 to 6, characterized in that At least six coils (12) are arranged on a circular track (K).

8. The rolling bearing according to any one of claims 1 to 7, characterized in that The magnet holder (13) is made of a material having a magnetic permeability of less than 2, preferably less than 1.5, and particularly preferably less than 1.

1.

9. The rolling bearing according to any one of claims 1 to 8, characterized in that The magnet holder (13) is made of austenitic steel or bronze.

10. The rolling bearing according to any one of claims 1 to 9, characterized in that The magnet holder (13) is welded to the holder (8).

11. The rolling bearing according to any one of claims 1 to 10, characterized in that The bar-shaped magnets (14) are held in the magnet holder (13) by webs (15) which are parallel to each other and separated from each other.

12. The rolling bearing according to any one of claims 1 to 11, characterized in that The bar-shaped magnets (14) are designed to have a constant width or, in order to make the arc lengths (b1, b2) of the respectively covered sections of the circular track (K) uniform, are designed to have different widths.

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