DE112013007412T5 - Bearing assembly comprising a sensor roller - Google Patents

Abstract

The invention relates to a bearing assembly comprising an inner ring (16), an outer ring (14), a plurality of rollers (10), comprising at least one sensor roller (10a) in a cage (18) between the inner ring (16) and the outer ring (14), wherein the sensor roller (10a) is provided with a bore (24) receiving a sensor unit (26) and at least a first portion of a generator assembly (28). It is contemplated that the generator assembly (28) includes a second portion provided by or disposed on the cage (18), wherein at least one magnetic circuit of the generator assembly (28) is at least partially spaced from the second portion as a function of relative rotation between the second assembly Cage (18) and the sensor roller (10a) is opened and closed, wherein the first portion of the generator assembly (28) is configured to interact with the second portion of the generator assembly to prevent relative rotation between the cage (18). and the sensor roll (10a) to generate energy.

Description

Technical area

The invention relates to a sensor roller and a bearing assembly comprising such a sensor roller.

Technical background

The provision of bearings with various sensors for load detection and for measuring temperature, rotation speed, noise, etc. is known. In some cases, sensors along with wireless transmitters are placed inside reels and need to be powered. One solution to this problem is the use of a battery. However, it has been found that the battery life falls below the bearing life in important applications and battery replacement is cumbersome.

The document EP 0637 734 A1 discloses a device for load measurement in roller bearings wherein the measurement is performed by means of sensors arranged to measure forces applied to the bearing. The sensors communicate with means for recording, processing and evaluating signals emitted by the sensors which are representative of the bearing load. Per roller body row at least one roller body is provided with a bore in which at least one sensor and means for amplifying and transmitting signals sent by the sensor to a receiver are provided. The receiver is provided on the non-rotating bearing ring of the bearing. The signals received by the receiver are forwarded to further external devices for signal processing.

The power supply of the transmission and amplification means is achieved by means of a small coil which is mounted in connection with the amplifier / transmitter in the bore of the roller and whose end protrudes outside the end of the roller. The coil is disposed in the sensor roller to communicate with a large stationary coil provided on the stationary bearing ring.

The stationary coil provides energy to the coil disposed in the roller, and the coil disposed in the bore sends continuous load data in the form of strain values from the sensors.

The solution in EP 0637 734 A1 has drawbacks in that the amount of energy that can be provided to the small coil may be limited particularly in the case of low rotational speeds of the bearing.

The document DE69828236 T2 teaches a bearing assembly having a roller with a bore providing a generator and gear within the bore. The transmission is connected via an elastic coupling element with a cage of the bearing.

In the DE69828236 T2 proposed solution has disadvantages in terms of robustness and life of the elastic coupling element. Furthermore, the elastic connection does not allow the internal components of the roller to be protected against damage by covering or slipping in the event of shocks or excessively high rotational speeds, and the elastic properties of the elastic coupling element are sensitive to temperature changes and subject to aging.

Summary of the invention

The object of the invention is to provide a sensor roll with integrated generator assembly with reduced maintenance costs, long life and potential for miniaturization.

The invention begins with a bearing assembly comprising an inner ring, an outer ring, a plurality of rollers, comprising at least one sensor roller, which is arranged in a cage between the inner ring and the outer ring, wherein the sensor roller is provided with a bore having a sensor unit and at least receives a first portion of a generator assembly.

It is contemplated that the generator assembly includes a second portion provided by or disposed on the cage, wherein at least one magnetic circuit of the generator assembly is at least partially opened and closed by the second portion as a function of relative rotation between the cage and the sensor roller; wherein the first portion of the generator assembly is configured to interact with the second portion of the generator assembly to generate energy from relative rotation between the cage and the sensor roller.

The distribution of the generator assembly via the sensor roller and the cage opens up the potential for miniaturization such that generators can be provided even for small bore rollers. Moving elements within the bore can be avoided, and thus the robustness and lifetime of the assembly can be further enhanced.

The use of a magnetic coupling instead of an elastic coupling element allows a practically wear-free operation and long life. The magnetic properties are less susceptible to external influences than elastic properties of an elastic coupling element. Furthermore, the magnetic interaction can be easily generated with permanent magnets and can contribute to the magnetic flux circuits used by the generator.

The invention is applicable to large sized roller bearings, such as bearings for wind turbines, which must be monitored. Restrictions 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 to be generated at a certain rotational speed. The bearings can be single-row or multi-row roller bearings and can be equipped with one or more sensor rollers per row.

The sensor unit may include strain sensors, temperature sensors, vibration sensors or other desired sensors.

It is further contemplated that the second portion of the generator assembly comprises at least one coil containing a magnetic flux of the magnetic circuit. The AC voltage induced in the coil can be used to generate energy.

In one embodiment of the invention, the generator assembly includes a brushless DC generator, wherein the first portion of the generator assembly is the stator portion of the brushless DC generator and the second portion of the generator assembly is the rotor portion of the brushless DC generator.

Preferably, the second portion of the generator assembly includes at least two permanent magnets disposed in positions symmetric about an axis of rotation of the sensor roller and connected by a high magnetic permeability metal plate.

In this case, it is preferable that the first portion of the generator assembly comprises at least one U-shaped magnetic core provided with at least one coil.

In another embodiment of the invention, the generator assembly includes a reluctance generator, wherein the first portion of the generator assembly is the stator portion of the reluctance generator and the second portion of the generator assembly is the rotor portion of the reluctance generator.

In this case, it is preferable that the first portion of the generator assembly comprises at least two permanent magnets arranged in positions symmetrical to a rotation axis of the sensor roller and connected to a magnetic core.

In the further embodiment of the invention, it is preferable that the second portion of the generator assembly comprises at least one high magnetic permeability metal plate arranged to face an axial end surface of a body of the sensor roller having an air gap.

The AC-to-DC converter and energy storage module may be a simple voltage output regulator (buck / boost) rectifier or a voltage multiplier circuit and a voltage regulator or battery charge circuit. Those skilled in the art will select the type of memory cell depending on the intended usage profile in combination with the roll speed profile. For example, for the detection of bearing defects, a measurement only makes sense when the bearing is moving. For static measurements such as temperature, strain, angle, etc., it is necessary to rely on the energy storage capacity of the module.

The type of energy storage device depends on the usage profile (measurement and transmission) in combination with the rotational speed profile. Strategies can be developed to perform measurements and transmission only when sufficient power is available from the generator, and to save the data in non-volatile memory under conditions where performance is insufficient. In this case, a small memory cell, for example a capacitor, can be used to cover the energy needs during data backup.

Furthermore, it is provided that the sensor unit comprises a wireless transmission unit in order to transmit sensor signals to a receiver unit.

Although the invention is applicable to other types of rollers such as toroidal roller bearings or tapered roller bearings, the widest possible applications are in cylindrical rollers.

Preferably, the sensor unit and the portion of the generator assembly received in the bore are preferably using encapsulated in a PUR potting compound to prevent corrosion by aggressive ingredients of lubricants used for the caster.

Preferably, the width of the air gap in the magnetic circuit separating the first and second sections of the generator assembly is at most 1 mm. Wider columns lead to insufficient efficiency of the generator assembly.

The above description of the invention as well as the appended claims, figures and the following description of preferred embodiments show several distinctive features of the invention in specific combinations. It will be readily apparent to those skilled in the art to contemplate other combinations or subcombinations of these features to adapt the invention as defined in the claims to its specific requirements.

Brief description of the drawings

1 is a schematic representation of a roller bearing comprising a sensor roller according to the invention.

2 is a schematic sectional view of the sensor roller of the bearing 1 ,

3 is a schematic sectional view of the sensor roller of a bearing according to a second embodiment of the invention.

4a - 4c show various configurations of a generator assembly of the bearing according to the invention, corresponding to the relative rotational positions of the sensor roller and the cage.

Detailed description of the embodiments

1 is a schematic representation of a roller bearing comprising a sensor roller 10a according to the invention.

The bearing is a single row roller bearing comprising a sensor roller 10a communicating wirelessly with a remote receiver unit 12 , for example, on the stationary ring 14 of the bearing or on a stationary ring 14 holding housing or spar is attached. The receiver unit 12 can have an integrated data processing device or an interface for forwarding the received data to another control and monitoring unit (not shown), which processes the sensor data as desired.

The bearing includes an inner ring 16 , an outer ring 14 and a plurality of cylindrical rollers 10 comprising the sensor roll 10a , In the case of this embodiment, the outer ring 14 the stationary ring.

The rollers 10 are in a cage 18 between the inner ring 16 and the outer ring 14 arranged. At the point of sensor roll 10a is the cage 18 with a metal plate 42 provided, at the two magnets 30a . 30b ( 2 ) are mounted.

2 is a schematic sectional view of the sensor roller 10a of the camp 1 ,

The sensor role 10a is with a hole 24 provided, which is a sensor unit 26 and at least a first section 28a a generator assembly 28 receives. The first paragraph 28a the in the sensor role 10a integrated generator module 28 is configured to work with the cage 18 to interact, resulting from a relative rotation between the cage 18 and the sensor role 10a Generate energy.

The generator module 28 includes a second section 28b who is at the cage 18 is arranged, wherein at least one magnetic circuit of the generator assembly 28 at least partially from the second section 28b as a function of relative rotation between the cage 18 and the sensor role 10a opened and closed. As a result, the reluctance of the magnetic circuit varies at a frequency proportional to the frequency of relative rotation between the pulley 10a and the cage 18 is proportional. Preferably, at least one permanent magnet is disposed in the magnetic circuit to generate a magnetic flux that oscillates in response to the variations in the reluctance of the magnetic circuit. The first paragraph 28a includes a coil pair 44a . 44b that's about a magnetic core 46 is wound, which conducts the magnetic flux, and in the coils 44a . 44b induced fluctuating voltage is used to generate electrical energy. This is the first section 28a the generator module 28 configured in the hole to work with the second section 28b the generator module 28 on the cage 18 interact to release energy from a relative rotation between the cage 18 and the sensor role 10a to generate.

In the in 2 illustrated embodiment is the generator assembly 28 formed as a brushless DC generator. The first paragraph 28a the generator module 28 plays the role of the stator section of the brushless DC generator, and the second section 28b the generator module 28 plays the role of the rotor section of the brushless DC generator, with the terms "stator" and "rotor" moving to a static position and one common to the body of the sensor roller 10a refer to rotating coordinate system relative rotation.

The second section 28b the generator module 28 includes two permanent magnets 30a . 30b which are arranged in positions symmetrical to a rotation axis of the sensor roller and through the metal plate 42 associated with high magnetic permeability. The magnetization directions of the permanent magnets 30a . 30b are identical and related to the axis of rotation of the sensor roller 10a axially aligned.

The first paragraph 28a the generator module 28 includes at least one U-shaped magnetic core 46 that with two coils 44a . 44b is provided around the axially extending legs of the core 46 are tortuous. In the rest position with minimal magnetic field energy, the axial end faces of the legs of the core 46 each one of the permanent magnets 30a . 30b facing, wherein between the permanent magnets 30a . 30b and the end faces of the core 46 a small air gap is provided.

The width of the air gap and the strength of the magnets 30a . 30b are chosen such that the magnetic flux is sufficiently strong to generate the required amount of energy, with slip of the roller 10a should of course be prevented due to excessive magnetic holding forces.

The generator module 28 further includes an AC-DC and energy storage circuit 32 and a wireless monitoring node 34 , The wireless monitoring node 34 includes the sensor unit 26 and a wireless transmission unit 36 for transmitting the sensor signals to the receiver unit in a wireless manner 12 ,

The AC-DC and energy storage circuits 32 includes a simple rectifier 38 with voltage output regulator (down / up), and storing energy is done with a simple capacitor 40 achieved, with more complicated tasks may require more complex energy storage solutions.

The wireless monitoring node 34 comprising the sensor unit 26 as well as the first section 28a the generator module 28 in the hole 24 are encapsulated using a polyurethane (PUR) potting compound to prevent corrosion by aggressive ingredients from lubricants used for the caster.

3 shows a further possible embodiment of the invention. In order to avoid repetition, the following description focuses on differences from the embodiment of FIG 1 and 2 , and the reader will look for characteristics that are similar or identical to the description of 1 and 2 directed. To clarify common functions or concepts, the same or similar reference numerals are used for features having identical or very similar functions.

In the embodiment in 3 includes the generator assembly 28 a reluctance generator, wherein the first section 28a the generator module 28 the stator section of the reluctance generator is and the second section 28b the generator assembly is the rotor portion of the reluctance generator. Again, the terms "stator" and "rotor" refer to a static position and one to a common with the body of the sensor roll 10a refer to rotating coordinate system relative rotation.

In this case it is the first section 28a the generator assembly, the two permanent magnets 30a . 30b includes, in to an axis of rotation of the sensor roller 10a symmetrical positions are arranged and with a magnetic core 46 are connected.

In the second embodiment of the invention, the second section comprises 28b the generator assembly at least one metal plate 42 with high magnetic permeability, which is arranged around an axial end face of a body of the sensor roller 10a to be facing with an air gap. The magnetic flux represented by arrows is thus through the body of the sensor roller 10a over the air gap to the metal plate 42 and radially inward of the permanent magnets 30a . 30b headed, im with a single coil 44 provided magnetic core 46 bundled and back into the body of the sensor roll 10a directed. The river reaches its maximum when the magnets 30a . 30b the metal plate 42 as in 4a are shown facing and is minimal when the elongated metal plate 42 as in 4c is aligned perpendicular to the axis of symmetry of the permanent magnet assembly. An intermediate configuration is in 4b shown. Of course, this principle can be easily generalized as needed for star-shaped magnet arrangements and metal plates.

In alternative embodiments of the invention, the cage 18 itself or parts thereof may be made of sufficiently magnetizable material, so that on the metal plate 42 could be waived.

The invention according to the two embodiments makes it possible to dispense with an external power source, and during the entire life of the bearing, the power can be generated internally. Compared with an embedded eccentric mass / pendulum type solution, significantly more power can be generated because of the force exerted by the magnetic interaction between the cage 18 and the generator shaft 42 is higher compared to the force generated by the eccentric mass.

Claims (12)

Bearing assembly comprising an inner ring ( 16 ), an outer ring ( 14 ), a plurality of rollers ( 10 ) comprising at least one in a cage ( 18 ) between the inner ring ( 16 ) and the outer ring ( 14 ) sensor roll ( 10a ), whereby the sensor roll ( 10a ) with a bore ( 24 ), which is a sensor unit ( 26 ) and at least a first portion of a generator assembly ( 28 ), characterized in that the generator assembly ( 28 ) a second section ( 28b ) received from the cage ( 18 ) is arranged, or arranged thereon, wherein at least one magnetic circuit of the generator assembly ( 28 ) at least partially from the second section as a function of relative rotation between the cage ( 18 ) and the sensor role ( 10a ) is opened and closed, the first section ( 28a ) of the generator assembly ( 28 ) is configured to communicate with the second section ( 28b ) of the generator assembly to interact to allow relative rotation between the cage (FIG. 18 ) and the sensor role ( 10a ) To generate energy. Bearing assembly according to claim 1, wherein the second section ( 28b ) of the generator assembly ( 28 ) at least one coil ( 44 . 44a . 44b ), which contains a magnetic flux of the magnetic circuit. Bearing assembly according to one of the preceding claims, wherein the generator assembly ( 28 ) comprises a brushless DC generator, the first section ( 28a ) of the generator assembly ( 28 ) is the stator section of the brushless DC generator and the second section ( 28b ) of the generator assembly ( 28 ) is the rotor portion of the brushless DC generator. Bearing assembly according to claim 3, wherein the second section ( 28b ) of the generator assembly ( 28 ) at least two permanent magnets ( 30a . 30b ), which in towards an axis of rotation of the sensor roller ( 10a ) symmetrical positions are arranged and by a metal plate ( 42 ) are associated with high magnetic permeability. Bearing assembly according to claim 3 or 4, wherein the first section ( 28a ) of the generator assembly at least one U-shaped magnetic core ( 46 ) provided with at least one coil. Bearing assembly according to one of the preceding claims, wherein the generator assembly ( 28 ) comprises a reluctance generator, wherein the first portion of the generator assembly ( 28 ) the stator section of the reluctance generator and the second section of the generator module ( 28 ) is the rotor portion of the reluctance generator. Bearing assembly according to claim 6, wherein the first section ( 28a ) of the generator assembly at least two permanent magnets ( 30a . 30b ), which in towards an axis of rotation of the sensor roller ( 10a ) symmetrical positions are arranged and with a magnetic core ( 46 ) are connected. Bearing assembly according to claim 7, wherein the second section ( 28b ) of the generator assembly at least one metal plate ( 42 ) is provided with high magnetic permeability, which is arranged to an axial end face of a body of the sensor roller ( 10a ) with an air gap in between. Bearing assembly according to one of the preceding claims, wherein the generator assembly ( 28 ) an AC to DC converter and energy storage circuit ( 32 ). Bearing assembly according to one of the preceding claims, wherein the sensor unit ( 26 ) a wireless transmission unit ( 36 ) for transmitting sensor signals to a receiver unit ( 12 ). Bearing assembly according to one of the preceding claims, wherein the sensor roller ( 10a ) is a cylindrical roller. Bearing assembly according to one of the preceding claims, wherein the sensor unit ( 26 ) and the first section of the generator assembly ( 28 ) in the hole ( 24 ) are encapsulated.

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