DE102022204576A1 - Rolling bearing with measuring roller - Google Patents

Abstract

The invention relates to a rolling bearing comprising a first bearing ring, a second bearing ring arranged rotatably relative to the first bearing ring, and at least one row of axially symmetrical rolling bodies (5) with at least one end face (7), the rolling bodies (5) running along the row of rolling bodies for transmitting forces a load direction (L) between the bearing rings and are accommodated in cage pockets spaced apart from one another by a cage, with a generator pole shoe (11) being arranged on the end face (7) of a rolling body (5) designed as a measuring roller (6), which has a plurality of coils (12) arranged on a circular path (K) coaxial with the rolling body axis (A) and interacts with a magnet holder (13) fastened opposite in the associated cage pocket, which carries a plurality of magnets (14), the magnets (14) are strip-shaped, the strip-shaped magnets (14) extending in the load direction (L) and covering the circular path (K) in sections.

Description

State of the art

The invention relates to a rolling bearing with a rolling body designed as a measuring roller according to the preamble of claim 1.

Rolling bearings, in particular large rolling bearings, with at least one rolling body designed as a measuring roller are known from the prior art. The measuring roller is used to record and store data in the interior of the bearing during operation of the rolling bearing or to transmit it wirelessly to the outside. In this way, for example, data on the current load on the rolling bearing, temperature, rotation speed, position and/or slip of the measuring roller can be recorded. To fulfill its tasks, the measuring roller requires electrical energy. The energy can, for example, be stored in the measuring roller using a battery, although the capacity of the battery limits the functionality of the measuring roller in time.

In order to overcome this disadvantage, autonomous energy supplies have already been proposed in the prior art to generate the electrical energy from the relative movement between the measuring roller and a cage pocket surrounding the measuring roller.

For example, this is off DE 698 28 236 T2 a rolling bearing with a rolling body is known which has a cylindrical hole in which an electrical energy generating device is arranged. The electrical energy generating device is a dynamometric generator or a Hertzian loop and is coupled via an elastic coupling element to the rolling element cage located outside the rolling element. The generator in the rolling element bore is driven by a reduction gear that is connected to the elastic coupling member. The disadvantage is that the rolling element contains a large number of moving parts and a mechanical connection to the cage is necessary to drive the generator. Both are potentially error-prone, with destruction of the elastic coupling even leading to foreign bodies in the bearing's raceway system, which can impair the function of the entire rolling bearing.

DE 11 2013 007 412 T5 therefore describes a sensor roller whose energy generation is based on a non-contact, inductive interaction between the sensor roller and the cage. The sensor roller has a bore that receives a sensor unit and a first section of a generator assembly. A second portion of the generator assembly is provided by the cage, with at least one magnetic circuit opening and closing as a function of relative rotation between the cage and the sensor roller. The second section of the generator assembly includes two permanent magnets connected by a metal plate with high magnetic permeability. The magnetization directions of the permanent magnets are identical and axially aligned with respect to the axis of rotation of the sensor roller. Limitations are given by the maximum degree of miniaturization for the generator assembly to be accommodated in the bore of the roller and the amount of power that can be generated at a certain rotation speed.

DE 10 2016 116 118 A1 describes a measuring roller with a microgenerator that has increased power output. For this purpose, a plurality of coils arranged on a circular path are provided, which are arranged on the measuring roller radially between a central bore of the measuring roller and its outer jacket. For example, at the location of the measuring roller, the cage includes four magnets that enable the microgenerator to induce a current.

However, these solutions known from the prior art have not proven to be particularly reliable. It was found that the known inductive generators often only provide a greatly reduced amount of electrical energy, especially in situations of increased load on the rolling bearing due to tilting moments.

Disclosure of the invention

The object of the 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 on the rolling bearing, which does not require any moving parts in the measuring roller.

This task is solved by a rolling bearing with the features of claim 1.

This creates a rolling bearing which comprises a first bearing ring, a second bearing ring arranged rotatably relative to the first bearing ring, and at least one row of axially symmetrical rolling bodies. The axially symmetrical rolling elements have at least one end face. The rolling elements of the rolling element row are arranged to be able to roll between the bearing rings in order to transmit forces along a load direction and are accommodated in cage pockets at a distance from one another in a cage. On the end face of a rolling body designed as a measuring roller, a generator pole shoe is arranged, which has a plurality of on a coaxial to the rolling body axis Carrying coils arranged in a circular path. The generator pole piece interacts with a magnet holder which is fastened opposite one another in the associated cage pocket and which carries a plurality of magnets. The magnets are strip-shaped, extend in the load direction and cover the circular path in sections.

The invention is based on the knowledge that loading situations on the rolling bearing can lead to deformations of the rolling bearing rings during operation, which negatively influence the energy generation of the measuring roller. Particularly in the case of uneven loads over the circumference of the rolling bearing rings, such as tilting moments, local deflections of ring sections in the load direction can occur, which are transmitted by the rolling bodies between the bearing rings. In contrast, the cage inserted into the raceway system with a certain amount of play experiences only a smaller deformation compared to the bearing rings, so that there is a relative movement between the rolling elements and the cage in the load direction. The relative movement reduces the energy yield of the inductive generators known from the prior art because the coils lose their alignment with respect to the magnets and the magnetic flux passing through the coils decreases accordingly. Even a shift of a few millimeters can lead to a collapse of the energy supply with the measuring rollers known from the prior art.

According to the invention, the relative movement between the cage and the rolling element is compensated for by the strip-shaped extension of the magnets in the load direction. The coils carried by the generator pole shoe therefore remain arranged opposite the respective magnet even under a relative movement between the cage and the measuring roller, so that the magnetic flux passing through the coils is maintained even under the relative movement.

In preferred embodiments, magnets arranged adjacent to one another along the circular path are polarized in opposite directions in the direction of the rolling body axis. By changing the polarization direction between all adjacent magnets, the energy yield is increased because an induced voltage occurs when the measuring roller rotates in each coil, which is shifted from the field of one magnet into the field of a magnet adjacent along the circular path. However, configurations are also conceivable in which the polarization of the magnets changes at larger intervals, for example two equally polarized magnets follow each other along the circular path.

In further preferred embodiments of the invention, the coils carried by the generator pole piece are connected in series, with mutually adjacent coils each having an opposite winding direction. The series connection of the coils allows the generator to be easily connected, with the changing winding direction of the coils ensuring a rectified addition of the induced voltage pulses.

It is further preferred that the strip-shaped magnets have a width transverse to the load direction that is at least as large as an inner diameter of the coils. The inner diameter of the coils defines the area 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 area is at least temporarily completely covered by the width of the strip-shaped magnets.

It is advantageous if a majority of the strip-shaped magnets have a length in the load direction that is at least twice as large as an outer diameter of the coils. Such an extension of the magnets ensures sufficient compensation of relative movements between the cage and the rolling elements in the load direction. In particular, it has been found that it is sufficient if a majority of the magnets ensure that the circular path is covered in sections, even under loads. If, for manufacturing reasons, not all magnets can be made the same length, this usually only has a minor effect on the power supply to the measuring roller.

The number of coils preferably corresponds to the number of strip-shaped magnets. This means that each coil is assigned exactly one magnet at any time during the movement on the circular path, which further increases the energy yield. At least six coils are preferably arranged on the circular path.

The magnet holder is preferably made of a material with a magnetic permeability less than 2, preferably less than 1.5 and particularly preferably less than 1.1. The magnetic permeability of the material is determined at the usual reference field strength of the magnetic field of 8,000 A/m (= approx. 100 Oe). It has been found that materials with a higher permeability lead to an at least partial short-circuit of the magnetic field lines within the magnet holder. This part of the magnetic flux provided by the magnet is then no longer available for inductive energy generation and leads to a noticeable reduction in energy yield. The lower the permeability of the material of the magnet holder, the greater the proportion of the magnet's magnetic flux that can be used to generate energy, thereby increasing the efficiency of energy generation.

The magnet holder is preferably made of an austenitic steel or bronze. Due to their microstructure, austenitic steels have a very low magnetic permeability close to 1 compared to ferrite or martensite steels. Austenitic steels and bronzes therefore have a combination of the advantageous properties of low magnetic permeability and high mechanical resilience and are therefore suitable for absorbing the mechanical loads on the rolling element cage even over long service lives. In principle, however, magnetic holders made of other materials are also conceivable, for example high-strength plastics such as PEEK.

In preferred embodiments, 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 over long service lives that the magnet holder remains in the cage pocket and that neither fasteners nor the magnet holder itself can come loose and get into the raceway system of the rolling bearing. However, other types of fastening, such as screwing or gluing, are also conceivable for the magnet holder.

The strip-shaped magnets are preferably held separately from one another in the magnet holder by webs that are parallel to one another. The webs also contribute to flux separation between neighboring magnets and thereby increase the energy yield.

Finally, it is advantageous if the strip-shaped magnets are of the same width or of different widths to equalize the arc lengths of the covered sections of the circular path. Magnets of equal width allow the use of standard components, such as rectangular magnets. On the other hand, equalizing the covered arc lengths using magnets of different widths has the advantage of a phase-synchronous addition of the voltage pulses induced in the coils, which contributes to a higher energy yield.

Further advantageous embodiments can be found in the following description and the subclaims.

The invention is explained in more detail below using the exemplary embodiments shown in the accompanying figures.

Brief description of the drawings

• 1 shows schematically an exemplary embodiment of a rolling bearing according to the invention with a rolling body designed as a measuring roller in a partially sectioned detailed view,
• 2 shows schematically a perspective view of the rolling body designed as a measuring roller 1 accommodated in a cage pocket of the rolling element cage with a magnet holder,
• 3A shows a schematic perspective view of the arrangement of the measuring roller and magnet holder 2 , whereby the magnet holder is only partially occupied with strip-shaped magnets,
• 3B and 3C show schematically the arrangement according to 3A without magnets in an unloaded and a loaded situation of the rolling bearing, and
• 4 shows schematically an arrangement of a measuring roller and a magnet holder according to a second exemplary embodiment in a front plan view.

Embodiments of the invention

In the various figures, the same parts are always provided with the same reference numbers and are therefore usually only named or mentioned once.

In 1 a partially sectioned detailed representation 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 arranged rotatably relative to the first bearing ring 2 and a row 4 of axially symmetrical rolling elements 5.

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 such that they can be rolled along a load direction L between the bearing rings 2, 3 in order to transmit forces. The rolling elements 5 are accommodated in cage pockets 9, 10 at a distance from one another in a cage 8.

On one of the end faces 7 of a rolling body 5 designed as a measuring roller 6, a generator pole piece 11 is arranged, which has a plurality of circular paths K coaxial with the rolling body axis A arranged coils 12 carries (cf. 3A) . The generator pole piece 11 cooperates with a magnet holder 13 which is fastened opposite one another in the associated cage pocket 10 and which carries a plurality of magnets 14. The magnets 14 are strip-shaped. The strip-shaped magnets 14 extend in the load direction L and cover the circular path K in sections.

The magnet holder 13 with the strip-shaped magnets 14 interacts with the coils 12 carried by the generator pole piece 11 to form an inductive generator.

Permanent magnets, in particular rare earth magnets, for example neodymium magnets, are preferably used as strip-shaped magnets 14.

2 shows a detailed representation of the measuring roller 6 accommodated in the cage pocket 10. Opposite the end face 7 of the measuring roller 6, the magnet holder 13 is fastened in the cage pocket 10. For this purpose, the magnet holder 13 is preferably inserted into a pocket-side recess 16 of the cage 8 and is particularly preferably glued therein.

In the circumferential direction of the rolling bearing, the measuring roller 6 is accommodated in the cage pocket 10 with a small amount of play between two partition walls 17 of the cage. A relative displacement of the generator pole shoe 11 arranged on the front side of the measuring roller 6 relative to the magnet holder 13 in the circumferential direction of the rolling bearing 1 is effectively prevented by this positive connection. However, depending on the load situation of the rolling bearing, a relative displacement of the generator pole shoe 11 relative to the magnet holder 13 in the load direction L can occur.

3A shows the arrangement of measuring roller 6 and magnet holder 13 in a perspective front view. The magnet holder 13 is only occupied with strip-shaped magnets 14 in the left half. In the right half, for the sake of clarity, the strip-shaped magnets have been removed to allow a view of the coils 12 and the generator pole shoe 11 behind them. In the normal operating state of the rolling bearing 1, the magnet holder 13 is fully occupied with magnets 14. In the 3B and 3C All magnets 14 have been removed to further simplify the illustration.

3A and 3B show measuring roller 6 and cage 8 in a no-load state of the rolling bearing 1. In the no-load state, the rolling body axis A pierces the magnet holder 13 in a central area between the strip-shaped magnets 14. In the loaded state, the rolling body axis A, however, pierces the magnet holder 13 at a point in the load direction L shifted, eccentric position.

As in 3A until 3C shown, it is advantageous if exactly one strip-shaped magnet 14 is provided for each coil 12. In such a configuration, the number of coils 12 corresponds to the number of strip-shaped magnets 14. Thus, during the rolling movement of the measuring roller 6, each coil 12 is assigned to one of the magnets 14 and its magnetic field flows through it. At least six coils 12 are preferred, for example ten coils 12 as in 3A until 3C shown, are arranged on the circular path K.

The magnets 14 arranged along the circular path K are preferably polarized in the direction of the rolling body axis A. Particularly preferably, magnets 14 arranged adjacent to one another are polarized in opposite directions. Furthermore, it is preferred if the coils 12 carried by the generator pole shoe 11 are connected in series, with mutually adjacent coils 12 each having an opposite winding direction. In such a configuration, the magnetic field lines of each of the magnets 14 run on the rolling body side through the interior of the coil 12 currently assigned to the magnet 14, through the generator pole piece 11, the interior of the adjacent coils 12 and the adjacent magnets 14 and are on the side of the rolling body facing away from the rolling body 5 Magnet holder 13 closed in the material of the cage 8. When the coil 12 moves through the magnetic fields of the magnets 14, the field direction inside the coil changes, as a result of which voltage pulses in the correct phase are generated in all coils 12.

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

In 4 a second exemplary embodiment of an arrangement according to the invention of measuring roller 6 and magnet holder 13 is shown, in which further geometric variables are designated.

For the most complete possible penetration of the coils 12 with the magnetic field of the strip-shaped magnets 14, the strip-shaped magnets 14 preferably have a width B transverse to the load direction L, which is at least as large as a Inner diameter d of the coils 12. It is then ensured that the coils 12 achieve the geometrically maximum possible overlap with the magnets 14 during the movement on the circular path K, thereby increasing the energy yield.

Furthermore, it is advantageous if a majority of the strip-shaped magnets 14 have a length I in the load direction L, which is at least twice as large as an outer diameter D of the coils 12. The length I of the magnets 14 determines the maximum tolerance of the generator to relative displacements between Measuring roller 6 and magnet holder 13 in the load direction L. For sufficient tolerance, it is sufficient if the majority of the coils 12 remain arranged opposite one of the magnets 14 even under load. In particular, a majority of the magnets 14 preferably have a length I of at least 2 cm, particularly preferably of at least 3 cm.

The above statements also apply to the in 3A until 3C illustrated embodiment, even if the width and length of the magnets 14 are not specifically designated there. Since the height of the magnet holder in the load direction L is limited by the height of the cage 8 (cf. 2 ), it may be necessary, in particular, to design the middle magnets 14 with a shorter length I in order not to exceed the maximum total height of the magnet holder 13 (cf. 3A until 3C ). Depending on the design of the rolling bearing, an asymmetrical arrangement of magnets may also be necessary in order to be able to maintain the dimensions of the magnet holder specified by the dimensions of the cage (not shown).

In contrast to the exemplary embodiment according to 3A until 3C are in the exemplary embodiment 4 the strip-shaped magnets 14 are not of the same width, but rather of different widths in order to equalize the arc lengths b1, b2 of the covered sections of the circular path K. By equalizing the arc lengths b1, b2, the change of the coils 12 between adjacent magnets 14 can be better synchronized during the rolling movement, which allows a phase-synchronous addition of the induced voltage pulses.

As in the exemplary embodiment 4 shown, the strip-shaped magnets 14 can in particular be rectangular, parallelogram-shaped or trapezoidal.

Another difference from the first exemplary embodiment is that in the exemplary embodiment according to 4 only eight coils 12 are arranged on the circular path K.

Otherwise, the comments on this apply 1 until 3 illustrated embodiment for the embodiment according to 4 accordingly.

Reference symbol list

1

roller bearing

2

first bearing ring

3

second bearing ring

4

Row of rolling elements

5

rolling elements

6

measuring roller

7

front side

8th

Cage

9, 10

Cage bags

11

Generator pole shoe

12

Kitchen sink

13

Magnetic holder

14

magnet

15

web

16

recess

17

Partitions

A

Rolling body axis

b1, b2

Arc lengths

b

Width of the strip-shaped magnets

d

Inside diameter of the coils

D

Outer diameter of the coils

K

circular path

I

Length of the strip-shaped magnets

L

Load direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 69828236 T2 [0004]
• DE 112013007412 T5 [0005]
• DE 102016116118 A1 [0006]

Claims (12)

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 axially symmetrical rolling bodies (5) with at least one end face (7), the rolling bodies (5 ) the row of rolling elements (4) for transmitting forces along a load direction (L) between the bearing rings (2, 3) are arranged so that they can be rolled and are accommodated in cage pockets (9, 10) spaced apart from one another by a cage (8), with on the end face ( 7) a generator pole shoe (11) is arranged on a rolling body (5) designed as a measuring roller (6), which carries a plurality of coils (12) arranged on a circular path (K) coaxial with the rolling body axis (A) and with one in the associated cage pocket (10) oppositely attached magnet holder (13) which carries a plurality of magnets (14), characterized in that the magnets (14) are strip-shaped, the strip-shaped magnets (14) extending in the load direction (L) and the Cover the circular path (K) in sections. Rolling bearings Claim 1 , characterized in that magnets (14) arranged adjacent to one another along the circular path (K) are polarized in opposite directions in the direction of the rolling body axis (A). Rolling bearings Claim 1 or 2 , characterized in that the coils (12) carried by the generator pole piece (11) are connected in series, with mutually adjacent coils (12) each having an opposite winding direction. Rolling bearings according to one of the Claims 1 until 3 , characterized in that the strip-shaped magnets (14) have a width (B) transverse to the load direction (L) which is at least as large as an inner diameter (d) of the coils (12). Rolling bearings according to one of the Claims 1 until 4 , characterized in that a majority of the strip-shaped magnets (14) have a length (I) in the load direction (L) which is at least twice as large as an outer diameter (D) of the coils (12). Rolling bearings according to one of the Claims 1 until 5 , characterized in that the number of coils (12) corresponds to the number of strip-shaped magnets (14). Rolling bearings according to one of the Claims 1 until 6 , characterized in that at least six coils (12) are arranged on the circular path (K). Rolling bearings according to one of the Claims 1 until 7 , characterized in that the magnet holder (13) is made of a material with a magnetic permeability less than 2, preferably less than 1.5 and particularly preferably less than 1.1. Rolling bearings according to one of the Claims 1 until 8th , characterized in that the magnet holder (13) is made of an austenitic steel or bronze. Rolling bearings according to one of the Claims 1 until 9 , characterized in that the magnet holder (13) is welded to the cage (8). Rolling bearings according to one of the Claims 1 until 10 , characterized in that the strip-shaped magnets (14) are held separately from one another in the magnet holder (13) by mutually parallel webs (15). Rolling bearings according to one of the Claims 1 until 11 , characterized in that the strip-shaped magnets (14) are of the same width or of different widths to equalize the arc lengths (b1, b2) of the covered sections of the circular path (K).

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