Method for ascertaining a rolling component state of a rolling bearing
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
- Filing Date
- 2024-08-12
- Publication Date
- 2026-06-24
Smart Images
Figure EP2024072758_20022025_PF_FP_ABST
Abstract
Description
[0001] Method for determining a rolling component condition of a rolling bearing
[0002] The following disclosure relates to a method for determining a rolling component condition of a rolling bearing and a rolling bearing arrangement for determining a rolling component condition of a rolling bearing.
[0003] In large mechanical systems, such as wind turbines, drilling machines, or cranes, rolling bearings with diameters of several meters are used to enable the rotational movement of very large and heavy components. A rolling bearing comprises two rolling bearing rings and a set of rolling elements that space the rings apart. The set of rolling elements usually comprises a rolling element cage and a plurality of rolling elements arranged in the rolling element cage and spaced apart by it.
[0004] During operation of such large-scale systems, damage to rolling bearing components can occur, impeding the relative movement of the rolling bearing rings. Minor damage is tolerable for most applications. However, during operation, the damage typically progresses to a state where the bearing can no longer be rotated and must therefore be replaced.
[0005] Early detection of such damage makes it possible to either plan a replacement of the rolling bearing at an early stage or to relieve the load on the bearing by intervening in the operational management in order to extend the remaining usable service life of the rolling bearing.
[0006] Various methods for the early detection of damage are known in the prior art. For example, a change in the deformation of the rolling bearing rings is used to infer damage to the rolling bearing. Another approach is to use measurements of metal particles in regularly taken grease samples from the interior of a rolling bearing to make statements about damage to the bearing caused by metal abrasion. Furthermore, structure-borne sound measurements are also carried out on rolling bearings to detect changes in the rolling bearings. What all of these methods have in common is that they are indirect measurement methods. This means that an attempt is made to derive information about damage based on measured variables that are not directly influenced by damage. Drive torques are also measured in the prior art to detect damage.However, frictional torques in large rolling bearings, such as those used in large-scale plants, are often high and a relative change in the drive torque in the early stages of a failure is usually below the measurement uncertainty of the measuring methods used to determine the drive torque.
[0007] The objective underlying this disclosure is therefore to present an improved approach for determining damage to a rolling bearing.
[0008] This improved approach is realized by the method according to claim 1 and the rolling bearing assembly according to claim 14.
[0009] In the following, the method for determining a rolling bearing component condition of the rolling bearing is first described in detail.
[0010] The method according to the invention comprises the following steps:
[0011] Providing a rolling bearing comprising a first rolling bearing ring, a second rolling bearing ring, and a rolling element set, wherein the first rolling element ring is spaced from the second rolling element ring by the rolling element set, and the rolling element set comprises a rolling element cage and a plurality of rolling elements arranged within the rolling element cage, wherein the rolling elements are in frictional contact with raceways of the rolling bearing rings;
[0012] Determining a first position of the rolling element set; after determining the first position, rotating the first rolling bearing ring relative to the second rolling bearing ring; after rotating, determining a second position of the rolling element set;
[0013] Determining a rolling component condition as a function of the second position and an expected position that the rolling element set should have reached starting from the first position with an unchanged rolling component condition and / or in the absence of rolling component damage; and
[0014] Output of a status signal depending on the determined rolling component status.
[0015] The method is based on the inventors' finding that damage to the rolling components affects how the rolling elements roll on the raceways and consequently how the position of the rolling element set changes after the rolling bearing rings rotate from an initial position. In particular, damage can affect rolling element slippage, in which the entire rolling element either slides on the raceways or spins. The slippage of the entire rolling element must be distinguished from drilling slip and Heathcote or differential slip, which also occur in undamaged rolling bearings and in which only parts of the rolling element surface have a different speed than the raceways. The changed slippage of the individual rolling elements influences the movement of the entire rolling element set.The condition of the rolling components can thus be determined using the second position and the expected position resulting from the first position. A comprehensive inspection of the rolling bearing is not necessary.
[0016] In contrast to the aforementioned indirect measurement methods of the prior art, the rolling component condition is determined according to the invention using the specific first and second positions, which are directly influenced by the damage. This allows for a more precise determination of the rolling component condition. Compared to the torque measurement used in the prior art, the method according to the invention can be reliably used even with large rolling bearings.
[0017] Advantageous embodiments of the method are described below.
[0018] The rolling components are those components of the rolling bearing that have a direct influence on the rolling action of the rolling elements on the raceways when the rolling bearing rings rotate. In one embodiment, the rolling component condition can relate to the condition of the rolling elements, the raceways of the rolling bearing rings, and / or the raceway cage. These three rolling components usually have the greatest influence on the rolling action of the rolling elements. In a variant of this embodiment, the rolling component condition corresponds in particular to the raceway condition. This is advantageous because the raceways are usually the most susceptible to abrasion and damage usually manifests itself first in the raceways, or damage to the raceways has the greatest impact on the serviceability of the rolling bearing. To define the condition of the rolling components, in some embodiments a distinction can be made between damage-free and damaged.In other embodiments, a distinction can be made, alternatively or additionally, between an unchanged state and a changed state. The latter classification can be used, for example, if it is not known whether an initial state of the rolling components is already defective, but a change can only be used to infer additional damage.
[0019] The rotation of the first rolling bearing ring relative to the second rolling bearing ring can be performed according to a travel path. The travel path is at least one relative rotational movement between the first rolling bearing ring and the second rolling bearing ring. In some embodiments, the travel path can also be a sequence of relative rotational movements. The travel path can alternatively or additionally be characterized by a travel path length, which corresponds, for example, to a radian measure by which the rolling bearing rings are moved relative to one another.
[0020] The first and second positions of the rolling element set, which are determined in the method according to the invention, can be defined as a position, in particular a rotational position, of the rolling element set within a rotational plane of the rolling element set. The rotational plane can, for example, be defined by a plane spanned by the centers of gravity of the plurality of rolling elements or can run parallel to this plane.
[0021] The status signal, which is output depending on the rolling element set, can be acoustic, optical and / or electronic, depending on the design of the method.
[0022] The expected position that would have been reached with an unchanged rolling component condition and / or in the absence of damage can vary depending on the configuration of the rotation of the first rolling bearing ring relative to the second rolling bearing ring. Embodiments of the method according to the invention are described below in which the expected position differs. In one embodiment of the method for determining the rolling component condition, for example, the first rolling bearing ring can be in a starting position relative to the second rolling bearing ring when determining the first position.When rotating the rolling bearing rings, in this method the first rolling bearing ring can be moved from the ring starting position via a first travel path to an intermediate ring position relative to the second rolling bearing ring and then rotated back to the ring starting position to determine the second position via a second travel path that corresponds to a reversal of the first travel path. In other words, within the scope of this embodiment, the first rolling bearing ring is rotated from a ring starting position relative to the second ring to an intermediate ring position relative to the second rolling bearing ring and then back to the ring starting position. If the rolling components of the rolling bearing are undamaged, it can be assumed that the rolling action of the rolling elements is identical on both travel paths and that the expected position corresponds to the first position within the scope of measurement uncertainties.In the event of damage, differences in the rolling action of the rolling elements may occur depending on the travel distance, for example due to asymmetrical material breakout due to material fatigue or asymmetrical abrasion due to wear.
[0023] In another embodiment of the method, the first rolling bearing ring can alternatively be rotated relative to the second rolling bearing ring by a travel distance. The expected position can correspond to the position of the rolling element set that the rolling element set would have had to reach starting from the first position if the rolling elements were to roll ideally on the raceways of the rolling bearing rings while rotating the rolling bearing rings according to the travel distance. Ideal rolling is understood here to mean the absence of sliding or spinning of the entire rolling element. In one variant of this embodiment, the expected position is calculated as a function of the geometry of the rolling bearing, the travel distance, and the first position. In another variant, drilling slip or Heathcote slip can also be taken into account when determining the expected position.These two forms of slippage lead to sliding or spinning of only a part of the rolling bearings and occur even in undamaged rolling components.
[0024] In a further embodiment of the method, the first rolling bearing ring can alternatively rotate relative to the second rolling bearing ring between determining the first position and the second position of the rolling bearing set according to a travel path. Furthermore, before determining the first position of the rolling element set, further positions of the rolling element set can be determined in addition to the first position and the second position using the following method steps:
[0025] Determining a first auxiliary position of the rolling element set;
[0026] After determining the first auxiliary position, rotating the first rolling bearing ring relative to the second rolling bearing ring according to the travel path;
[0027] After rotating, determining a second auxiliary position of the rolling element set; and wherein the expected position is determined using the first auxiliary position, the second auxiliary position and the first position.
[0028] The first auxiliary position and the second auxiliary position, like the first position and the second position, are positions of the rolling element set. Using the auxiliary positions, it can be determined how far the rolling element set moves for a given travel distance at a first point in time. By determining the first and second positions for the same travel distance, a movement of the rolling element set at a second point in time can then be determined, with the rolling bearing performing its intended operation between the first and second points in time. If the rolling components remain unchanged, the movement of the rolling element set at the first and second points in time should be identical within the measurement uncertainty.
[0029] In a variant of this procedure, the expected position can therefore correspond to a sum of the first position and a difference between the second auxiliary position and the first auxiliary position.
[0030] Based on the expected position and the second position, the rolling component condition can be deduced. How this can be achieved is demonstrated using the embodiments of the method described below. In one of these embodiments, for example, the rolling component condition can be determined depending on a difference between the second position and the expected position. The difference serves as a measure of a deviation between the expected position and the second position. In particular, an absolute value of the difference can also be calculated within the scope of the method.
[0031] In a variant of this embodiment, the difference, or an absolute value of the difference, can additionally be compared with a predefined limit value, and the rolling component condition can be determined depending on the result of this comparison. Using the limit value, for example, method tolerances such as statistical fluctuations can be taken into account. This makes it possible to determine whether a difference value actually indicates damage or a change in the rolling element condition, or whether it is rather an expected fluctuation in the value. In this context, for example, a difference that is smaller than the limit value can additionally or alternatively be used to conclude that the rolling component condition is free of damage and / or unchanged. If the limit value is greater than the difference, a deterioration in the rolling component condition can additionally or alternatively be concluded.
[0032] In another variant of this embodiment, the limit value can additionally or alternatively be a relative limit value that depends on a travel path used when rotating the first rolling bearing ring relative to the second rolling bearing ring, in particular a travel path length of the used travel path. A longer travel path can result in a greater deviation from the expected position to the second position. This effect can be compensated for by the relative limit value.
[0033] The first position and the second position can be determined in various ways. In another embodiment, the first position and / or the second position can be determined additionally or alternatively by measuring an angle, in particular an angle in a range of 1° to 360°, between the rolling element set and a non-rotating fixed point.
[0034] In another embodiment, the first position and / or the second position can be determined additionally or alternatively by measuring a distance between a non-rotating fixed point and a rolling element of the rolling element set closest to the fixed point. A distance measuring unit can be provided to measure the distance. This can be designed, in particular, to measure a distance between the distance measuring unit itself and the rolling element closest to the distance measuring unit. In variants of this embodiment, the distance measuring unit can comprise, for example, an induction sensor or an ultrasonic sensor.
[0035] To arrange the distance measuring unit in the vicinity of the rolling element set, a through hole can also be machined through one of the rolling bearing rings, in which the distance measuring unit can be arranged. This can enable a space-saving and simultaneously protected arrangement of the distance measuring unit. Depending on the nature of the rolling elements, there are different, advantageous arrangements of the through hole within the rolling bearing ring. An advantageous arrangement of the distance measuring unit can be characterized in particular by the fact that a difference in a measured value of the distance measuring unit is as large as possible, depending on whether the rolling element closest to the distance measuring unit has a minimum or maximum distance from the distance measuring unit.
[0036] In one variant, for example, the rolling elements can be designed as rolling balls, each having a rolling element center of gravity, with the rolling element centers of gravity moving along a circular path as the rolling bearing rings rotate. It can be advantageous to arrange the through-hole, which has a longitudinal axis, within the rolling bearing ring such that a distance between an alignment of the through-hole along the longitudinal axis and the circular path at a point of closest proximity between the circular path and the alignment of the through-hole is less than or equal to a radius of the rolling balls. In particular, it can be advantageous if the alignment intersects the circular path.
[0037] If the rolling elements are rollers, each with a rotational axis and a rolling element side surface arranged perpendicular to the rotational axis, a different arrangement is possible. Here, the through-hole within one of the rolling bearing rings can be arranged such that, upon relative movement of the rolling bearing rings to one another, the side surfaces of the rolling rollers roll past an opening in the through-hole, and a center point of the opening is arranged outside a plane spanned by the rotational axis and a velocity vector of a rolling element rolling past the opening. In particular, the center point can be spaced from the plane by equal to or more than 1 / 3, in particular 2 / 3, of a radius of the rolling rollers.
[0038] The rolling bearing assembly mentioned above for determining the rolling component condition of a rolling bearing will now be described in detail. According to the invention, the rolling bearing assembly comprises a rolling bearing having a first rolling bearing ring, a second rolling bearing ring, and a rolling element set. The first rolling bearing ring is spaced apart from the second rolling bearing ring by the rolling element set, and the rolling element set comprises a rolling element cage and a plurality of rolling elements arranged within the rolling element cage. Furthermore, each of the plurality of rolling elements is in frictional contact with raceways of the rolling bearing rings. Furthermore, the rolling bearing assembly comprises a control unit, a position determination unit, and an evaluation unit. The control unit is configured to rotate the first rolling bearing ring relative to the second rolling bearing ring.The position-determining unit is configured to determine a first position of the rolling element set before the first rolling bearing ring rotates relative to the second rolling bearing ring, and to determine a second position of the rolling element set after the rotation. The evaluation unit is configured to determine a rolling component state as a function of the second position and an expected position that the rolling element set should have reached starting from the first position with an unchanged rolling component state and / or in the absence of rolling component damage. Furthermore, the rolling bearing arrangement comprises an output unit configured to output a state signal as a function of the determined rolling component state.
[0039] In one embodiment, the rolling bearing of the rolling bearing arrangement may be a large rolling bearing having a diameter of at least one meter.
[0040] In one embodiment of this arrangement, the rolling bearing assembly can, for example, be incorporated into a wind turbine. In a variant of this embodiment, the rolling bearing can, for example, be part of a rotor blade bearing of the wind turbine. In this specific application, the rolling bearing assembly can detect damage to the rotor blade bearing at an early stage, preventing blade shedding due to a failure of the rotor blade bearing and thus significantly increasing safety.
[0041] In the following, exemplary embodiments of the method and the arrangement are described with reference to the accompanying figures. First, an overview of the figures is provided.
[0042] Fig. 1 shows an example of a method for determining a rolling component condition of a rolling bearing;
[0043] Fig. 2 illustrates, using a rolling bearing, a process according to the method of Fig. 1;
[0044] Fig. 3 illustrates an alternative process using the rolling bearing from Fig. 2;
[0045] Fig. 4 illustrates another alternative process using the rolling bearing from Fig. 2;
[0046] Fig. 5a shows a plan view of an example of a rolling bearing assembly comprising a rolling bearing and a distance measuring unit arranged in a through hole;
[0047] Fig. 5b shows a section of a cross section through the rolling bearing from Fig. 5a;
[0048] Fig. 6 shows a graphical evaluation of the first and second positions of a set of rolling elements determined within the framework of the method from Fig. 1 using the distance measuring unit shown in Figs. 5a and 5b;
[0049] Fig. 7 shows a section of a cross section through a rolling bearing comprising a rolling element set with rolling rollers and a distance measuring unit arranged in a through hole;
[0050] Fig. 8a shows a rolling bearing arrangement for determining a rolling component condition of a rolling bearing; and
[0051] Fig. 8b shows a wind turbine comprising the rolling bearing arrangement from Fig. 8a.
[0052] The following describes in detail what is shown in the figures. Components of the methods and devices shown are referred to in the description of the figures using reference symbols. The same reference symbols are used for identical components.
[0053] First, an embodiment of a method for determining a rolling component condition of a rolling bearing is described with reference to Fig. 1 and Fig. 2.
[0054] Fig. 1 shows an example of a method 100 for determining a rolling component condition of a rolling bearing. Fig. 2 shows a rolling bearing 120 as used in the method 100 shown in Fig. 1.
[0055] The method 100 comprises a total of six method steps. In a first method step 102, the rolling bearing 120 is provided. The rolling bearing 120 comprises a first rolling bearing ring 122, a second rolling bearing ring 124, and a rolling element set 126. The first rolling element ring 122 is spaced from the second rolling element ring 124 by the rolling element set 126, and the rolling element set 126 has a rolling element cage 126.1 and a plurality of rolling elements 126.2AN arranged within the rolling element cage 126.1. The plurality of rolling elements 126.2AN are in frictional contact with raceways 122.1, 124.1 of the rolling bearing rings, on which they roll during a rotational movement of the first rolling bearing ring 122 relative to the second rolling bearing ring 124.
[0056] In a step 104, a first position of the rolling element set 126 is determined. In a step 106 following step 104, the first rolling bearing ring 122 is rotated relative to the second rolling bearing ring 124. In a subsequent step 108, a second position of the rolling element set 126 is determined. Subsequently, in a step 110 following step 108, a rolling component state is determined as a function of the second position and the first position. In a concluding step 112, a state signal is output as a function of the determined rolling component state.
[0057] The rolling components of the rolling bearing 120 are all components that can have a direct influence on the rolling action of the rolling elements 126.2AN on the raceways of the rolling bearing rings. These include, in particular, the rolling elements 126.2AN themselves, the raceways 122.1 and 124.1, and the rolling element cage 126.1. Damage to one or more of the rolling components can affect the rolling action of the rolling elements 126.2AN on the raceways 122.1, 124.1. In particular, it can lead to increased sliding and spinning of the entire rolling element on the raceways of the rolling bearing rings. This influences the second position, whereby a change in the rolling component condition can be detected by detecting the second position. Damage that may occur is in particular abrasion on a surface of the rolling elements 126.2AN or the raceways 122.1, 124.1.Structural damage, such as shattering, of the rolling elements 126.2AN and the rolling element cage 126.1 may also occur. However, damage to the raceways of the rolling bearing rings generally predominates, which is why the following considerations are limited to these.
[0058] There are various ways to draw conclusions about the rolling component state from the determined first position and the determined second position. In the example shown in Figs. 1 and 2, a difference is formed between the second position and an expected position. The expected position results from how the rolling bearing rings rotate. In the rolling bearing 120, when the rolling bearing rings 122, 124 rotate, the second rolling bearing ring 124 is held stationary and the first rolling bearing ring 122 is moved relative to the second rolling bearing ring 124. In the method 100, the first rolling bearing ring 122 is initially in a ring starting position relative to the second rolling bearing ring 124. In the example of Fig. 2, the ring starting position is characterized in that a marking point 122M of the first rolling bearing ring 122 is in a zero position N.A marking 126M of the rolling element set 126 is also in the zero position N before the rolling bearing rings move relative to one another, which corresponds to the first position, marked PI here. The markings 122M and 126M primarily serve to illustrate the position of the first rolling bearing ring and the rolling element set. The positions can also be determined in other ways, as will be explained in more detail later. During rotation, the first rolling bearing ring 122 is then moved to an intermediate ring position W, as illustrated by the now displaced marking 122M' in Fig. 2. The first rolling bearing ring 122 is then moved back to the zero position N. This back-and-forth movement is also indicated by the arrow 128. Following the back-and-forth movement, the second position of the rolling element set is determined.In the case of a damage-free raceway condition, it can be assumed that the second position of the rolling element set determined in step 108, indicated in Fig. 2 by a plane P2, corresponds to the first position PI. The first position PI therefore corresponds to the expected position. In method 100, the difference between the second position P2 and the expected position or first position is compared with a limit value. If the difference is greater than the limit value, the raceway condition is classified as damaged. However, if the difference is below this limit value, the raceway condition is classified as damage-free. By selecting the limit value, it can be determined at which extent of damage a condition signal should be output. This is helpful, for example, in cases in which a rolling bearing can initially continue to run unchanged in the event of minor damage and maintenance of the rolling bearing is only required when the damage reaches a certain extent.In addition, the limit value can be used to account for statistical fluctuations and intrinsic measurement uncertainties when determining positions. The limit value can also be defined so that it depends on the length of a travel path.
[0059] As an alternative to the reciprocating motion of the rolling bearing rings relative to each other, other process configurations can also be used. These are described below using Fig. 3 and Fig. 4.
[0060] Fig. 3 illustrates an alternative process using the rolling bearing 120 from Fig. 2.
[0061] As an alternative to the back-and-forth movement of method 100, it is also possible to move the first ring 122 relative to the second ring 124 by any desired travel path as part of step 106. This travel path is indicated, for example, in Fig. 3 by the rotational movement indicated by arrow 228, which brings the marking 122M of the first ring into a plane W', as indicated by the marking 122M'. If the rolling element set 126 is at the zero position N before movement, as indicated in Fig. 3 by the marking 126M, the expected position of the rolling element set 126 after the movement 228 of the rolling bearing rings 122, 124 can be determined based on the geometric dimensions of the rolling bearing 120, the travel path 228, and under the assumption that the rolling elements 126.2AN roll ideally on the raceways 122.1, 124.1. The expected position is indicated in Fig. 3 by the plane E.A deviation of the second position, indicated by plane P2, from this plane E may indicate raceway damage. The term "ideal rolling" refers to the rolling element not sliding or spinning as a whole on raceways 122.1 and 124.1 during rolling.
[0062] In another variant of the procedure, the expected position can also be determined using a previously performed measurement. This is described below with reference to Fig. 4.
[0063] Fig. 4 illustrates a further alternative method implementation using the rolling bearing 120 from Fig. 2. In the rolling bearing 120 shown in Fig. 4, the first rolling bearing ring 122 is initially located at the zero position N, as indicated by the marking 122M. The rolling element set 126 is also located at the zero position, as indicated by the marking 126M. The position of the rolling element set 126 is referred to as a first auxiliary position H1. Subsequently, the first rolling bearing ring 122 is moved along a travel path indicated by arrow 328 to a ring position W, as also indicated by the marking M122'. The rolling element set 126 is thereby displaced to a second auxiliary position, which is indicated by a plane H2. Now, the intended operation of the rolling bearing 120 is continued regularly, ie without determining positions, and the first rolling bearing ring 122 is moved further, which is indicated in Fig. 4 by way of example by an arrow 328'.After a certain time, the first rolling bearing ring 122 is located at a ring position W', as indicated by a marking 122M". The rolling element set 126 has moved further accordingly and is now located at the first position, which is marked with a plane PI. Now, the first rolling bearing ring 122 is rotated by the same travel distance 328 to a ring position W", as also illustrated by a marking 122M"'. The rolling element set 126 is then located at the second position, which is illustrated by a plane P2 in Fig. 4. If a raceway state of the raceways 122.1, 124.1 remains unchanged from the state of the raceways 122.1, 124 during the rotation of the first rolling bearing ring 122 from the position W' to the position W".1 when rotating the first rolling bearing ring 122 from the zero position N to the ring position W, a difference between the second auxiliary position H2 and the first auxiliary position H1 should be equal to a difference between the second position P2 and the first position PI of the rolling element set 126. This results in the expected position, which is illustrated in Fig. 4 with the plane E. A deviation from this may indicate a deterioration of the raceway condition.
[0064] By means of the marking 126M of the rolling element set 126 in Figs. 2-4, the position of the rolling element set 126 relative to a fixed point, for example the zero position N, can be clearly specified with an angle with a value range of 1 to 360°, up to a multiple of whole revolutions. This can be achieved, for example, using a rotary encoder. However, such a clear indication is often only technically feasible using complex means. However, a clear position indication is not absolutely necessary for the present application. In one embodiment of the method, the first position and the second position are therefore specified in the form of a distance between a distance measuring unit and a rolling element closest to the distance measuring unit. This is described below with reference to Figs. 5a and 5b and Fig. 6.
[0065] Fig. 5a shows a top view of a rolling bearing assembly 200 comprising a rolling bearing 220 and a distance measuring unit 240 arranged in a through-hole. Fig. 5b shows a section of a cross-section through the rolling bearing 220 from Fig. 5a. The cross-section runs along the cross-sectional plane AA shown in Fig. 5a. Fig. 6 shows a graphical representation of exemplary distance measurements recorded with the rolling bearing assembly 200.
[0066] The rolling bearing 220 comprises a first rolling bearing ring 222, which is designed as an outer rolling bearing ring, and a second rolling bearing ring 224, which is designed as an inner rolling bearing ring. Recesses in the rolling bearing rings form two intermediate spaces 223A and 223B, in each of which a set of rolling elements (not shown) is arranged. Rolling elements of the rolling element set arranged in the intermediate space 223A are in frictional contact with a raceway 222.1A of the first rolling bearing ring 222 and a raceway 224.1A of the second rolling bearing ring 224. Rolling elements of the rolling element set arranged in the intermediate space 223B are in frictional contact with a raceway 222.1B of the first rolling bearing ring 222 and a raceway 224.1B of the second rolling bearing ring 224. The intermediate spaces 223A, 223B are each delimited by a cover 228A or 228B. In the case of the cover 228A or228B is a sealing ring that prevents grease from escaping from the rolling bearing 220 or that environmental components from penetrating the rolling bearing 220.
[0067] The second rolling bearing ring 224 has two through holes 224.2A and 224.2B, which run perpendicular to a rotational axis of the second rolling bearing ring 224 and are each open to one of the intermediate spaces 223A, 223B. A distance measuring unit 240A or 240B is arranged within each of the through holes. Each of the distance measuring units 240A, 240B is designed to determine a distance from the respective distance measuring unit to a rolling element closest to the distance measuring unit. The distance measuring unit 240A, 240B can be, for example, an induction sensor. As an alternative to an induction sensor in a through hole, an ultrasonic sensor can also be used as the distance measuring unit. This ultrasonic sensor is aligned with the raceways and is designed to detect a position of a nearest rolling element through the rolling bearing rings.
[0068] In Fig. 6, a graphical evaluation 300 of the positions of the rolling element set in the intermediate space 223A determined in the context of the method 100 using the distance measuring unit 240A is shown as an example.
[0069] The distance 302 (y-axis) determined by the distance measuring unit 240A is plotted over a running time 304 (x-axis) of the rolling bearing 200. The running time 304 is divided into two time periods 304A and 304B, whereby between 304A and 304B the rolling bearing was operated for a longer period of time for its intended use. In time period 304A, the raceways 222.1A, 224.1A of the rolling bearing 220 are initially free of damage, and in time period 304B they exhibit raceway damage. In each time period 304A, 304B, three point pairs PP1-3 and PP4-6 are plotted. Each point pair corresponds to the first position determined within the scope of method 100 and the second position determined. Between determining the first position PI and the second position P2, the first rolling bearing ring 222 was moved back and forth relative to the second rolling bearing ring 224, as previously described.The determination of the raceway condition was illustrated graphically for point pair PPI of time period 304A and point pair PP4 of time period 304B. For both point pairs, a difference D or D' was first determined between the second position P2 or P2' and the first position PI or PI'. The difference was then compared with a limit value G. In the case of point pair PPI, the difference D is smaller than the limit value G, therefore it is concluded that the raceway condition is free of damage. For point pair PP4, however, the difference D' is greater than the limit value G. Therefore, it is concluded that the raceway condition has changed. It should also be noted here that the travel path of the rolling bearing rings between determining the first position and determining the second position of a point pair was selected to be the same for all point pairs to ensure comparability between the point pairs.
[0070] In Fig. 5a and Fig. 5b, the through-hole 224.2A is arranged within the second ring 224 such that an alignment of a longitudinal axis 224.2A.1 of the through-hole 224A.2A intersects a circular path on which the centers of mass of the rolling elements move during a relative movement between the first rolling bearing ring 222 and the second rolling bearing ring 224. The circular path is indicated in Fig. 5b by a cross 225A. The same applies to the through-hole 224.2B. This can be advantageous so that a difference in a measured value of the distance measuring unit is as large as possible, depending on whether the rolling element closest to the distance measuring unit has a minimum or a maximum distance from the distance measuring unit. In the case of rolling elements that are designed as rolling balls, as in Fig. 5a and Fig.5b, it is therefore generally advantageous if the through-hole is arranged within the rolling bearing ring such that the distance between an alignment along a longitudinal axis of the through-hole and a circular path along which the centers of gravity of the rolling rollers move is less than or equal to a radius of the rolling balls at a point of closest approach between the circular path and the alignment. However, if the rolling elements are rollers, a different arrangement of the through-hole may be appropriate. Such an arrangement is discussed below with reference to Fig. 7.
[0071] Fig. 7 shows a section of a cross section through a rolling bearing 400, which comprises a rolling element set with rolling rollers.
[0072] The rolling bearing 400 comprises a first rolling bearing ring 422 and a second rolling bearing ring 424. The rolling bearing ring 424 is spaced apart from the rolling bearing ring 422 by two rolling element sets, each comprising a rolling element cage and a plurality of rolling elements configured as rolling rollers. For better clarity, only one rolling roller 426A and 426B of each of the rolling bearing sets is shown in Fig. 7. Two through holes 423A, 423B are provided in the first rolling bearing ring 422 for arranging a distance measuring unit. The through hole 423A is arranged such that a center point of the opening 423A.2 does not lie within a plane 425A spanned by a rotational axis 426A.1 of the roller 426A rolling past the opening and its velocity vector. In particular, the center point is spaced from the plane 425A by a distance A, which corresponds to approximately 1 / 3 of the radius of the rollers.The same applies to the arrangement of the through hole 423B. The centers of the openings 423A.2, 423B.2 are shown in Fig.
[0073] 7 each represented by a longitudinal axis 423A.1, 423B.1 of the respective through hole 423A or 423B.
[0074] In the following, an arrangement for determining a rolling component condition of a rolling bearing will now be described with reference to Fig. 8a and Fig. 8b.
[0075] Fig. 8a shows a rolling bearing assembly 500 for determining a rolling component condition of a rolling bearing 520.
[0076] The rolling bearing 520 has a first rolling bearing ring 522, a second rolling bearing ring 524, and a rolling element set 526, wherein the first rolling bearing ring 522 is spaced from the second rolling bearing ring 524 by the rolling element set 526. Furthermore, the rolling element set 526 has a rolling element cage 526.1 and a plurality of rolling elements 526.2AN arranged within the rolling element cage 526.1, wherein each of the plurality of rolling elements is in frictional contact with raceways 522.1, 524.1 of the rolling bearing rings 522, 524.
[0077] The rolling bearing assembly 500 further comprises a control unit 570, a position-determining unit 540, and an evaluation unit 560, which is electrically connected to the control unit 570 and the position-determining unit 540. The control unit 570 is configured to rotate the first rolling bearing ring 522 relative to the second rolling bearing ring 524 by means of a rolling bearing ring motor 575, which is also included in the assembly 500. The position-determining unit 540 is configured to determine a first position of the rolling element set 526 before the first rolling bearing ring 522 rotates relative to the second rolling bearing ring 524 and to determine a second position of the rolling element set 526 after the rotation. For this purpose, the position determination unit 540 comprises a distance measuring unit configured to determine a distance between the distance measuring unit and a rolling element closest to the distance measuring unit. However, the position determination can also be performed differently.Furthermore, the evaluation unit 560 is designed to determine the rolling component state as a function of the second position and an expected position that the rolling element set would have had to reach starting from the first position with an unchanged rolling component state and / or in the absence of rolling component damage.
[0078] In addition, the rolling bearing assembly 500 includes an output unit 580. The output unit 580 is configured to receive the determined rolling component condition and output a condition signal depending on the determined rolling component condition. In the example shown in Fig. 8a, the output unit 580 is a mobile radio transmission unit, and the condition signal is an electromagnetic mobile radio signal. However, other forms of signal output can also be used.
[0079] The diameter of the rolling bearing 520 is several meters. The rolling bearing 520 can therefore be used in a variety of large-scale mechanical systems, such as wind turbines, drilling machines, cranes, or similar. In principle, however, the diameter of the rolling bearing 520 could also be smaller. The following describes its use in a wind turbine using Fig. 8b.
[0080] Fig. 8b shows a wind turbine 600 comprising the rolling bearing arrangement 500 from Fig. 8a.
[0081] The wind turbine 600 comprises a tower 606, at the upper end of which a nacelle 608 is rotatably mounted. Located inside the nacelle 608 is a generator connected to a rotor 604 via a shaft. Three rotor blades 602A-C are connected to the rotor 604. The rotor blades 602A-C are each rotatably connected to the rotor 604 via a rolling bearing 520 in order to be able to change the angle of attack of the rotor blades 602A-C. A rolling bearing arrangement 500 is used to monitor each of the rolling bearings. The position-determining unit 540 is arranged such that it is positioned in a zero-load zone of the rotor blade.
[0082] As an alternative to using the rolling bearing for the rotatable support of the rotor blades 602A-C, the rolling bearing 520 can also be used, for example, for the rotatable support of the nacelle or for the support of the shaft.
[0083] In summary, this disclosure describes a method (100) for determining a rolling component condition of a rolling bearing (120), comprising the following method steps: providing the rolling bearing (120) which has a first rolling bearing ring (122), a second rolling bearing ring (124) and a rolling element set (126), wherein the first rolling element ring (122) is spaced from the second rolling element ring (124) by the rolling element set (126), and the rolling element set (126) comprises a rolling element cage (126.1) and a plurality of rolling elements (126.2AN) arranged within the rolling element cage (126.1), wherein the rolling elements (126.2AN) are in frictional contact with raceways (122.1, 124.1) the rolling bearing rings (122, 124) are stationary (102); determining a first position (PI) of the rolling element set (104); after determining the first position (PI), rotating the first rolling bearing ring relative to the second rolling bearing ring (106); after rotating, determining a second position (P2) of the rolling element set (108); determining a rolling component state as a function of the second position (P2) and an expected position (E) that the rolling element set (126) should have reached starting from the first position (PI) with an unchanged rolling component state and / or in the absence of rolling component damage (110); and outputting a state signal as a function of the determined rolling component state (112).
Claims
Patent claims 1. Method (100) for determining a rolling component condition of a rolling bearing (120), comprising the following method steps: Providing the rolling bearing (120) having a first rolling bearing ring (122), a second rolling bearing ring (124) and a rolling element set (126), wherein the first rolling element ring (122) is spaced from the second rolling element ring (124) by the rolling element set (126) and the rolling element set (126) comprises a rolling element cage (126.1) and a plurality of rolling elements (126.2AN) arranged within the rolling element cage (126.1), wherein the rolling elements (126.2AN) are in frictional contact with raceways (122.1, 124.1) of the rolling bearing rings (122, 124) (102); Determining a first position (PI) of the rolling element set (104); after determining the first position (PI), rotating the first rolling bearing ring relative to the second rolling bearing ring (106); after rotating, determining a second position (P2) of the rolling element set (108); Determining a rolling component condition as a function of the second position (P2) and an expected position (E) that the rolling element set (126) should have reached starting from the first position (PI) with an unchanged rolling component condition and / or in the absence of rolling component damage (110); and Outputting a status signal depending on the determined rolling component status (112).
2. The method (100) according to claim 1, wherein the rolling component condition relates to a condition of the rolling elements (126.2AN), a condition of the raceways (122.1, 124.1) and / or a condition of the rolling element cage (126.1).
3. Method (100) according to claim 1 or 2, wherein when determining the first position (PI), the first rolling bearing ring (122) is located in a ring starting position (N) relative to the second rolling bearing ring (124); and when rotating, the first rolling bearing ring (122) is brought from the ring starting position (N) via a first travel path first into a ring intermediate position (W) relative to the second rolling bearing ring (124) and then to Determining the second position (P2) is rotated back to the ring starting position (N) via a second travel path which corresponds to a reversal of the first travel path; wherein the expected position (E) corresponds to the first position (PI).
4. The method (100) according to claim 1 or 2, wherein the first rolling bearing ring (122) is rotated relative to the second rolling bearing ring (124) by a travel path (238); and the expected position (E) corresponds to the position of the rolling element set (126) which the rolling element set (126) would have had to reach starting from the first position (PI) if, during the rotation of the rolling bearing rings (122, 124) according to the travel path (238), the plurality of rolling elements (126.2AN) were to roll ideally on the raceways (122.1, 124.1) of the rolling bearing rings (122, 124).
5. The method (100) according to claim 1 or 2, wherein the rotation of the first rolling bearing ring (122) relative to the second rolling bearing ring (124) takes place between the determination of the first position (PI) and the second position (P2) of the rolling bearing set (126) according to a travel path, and before the determination of the first position (PI) of the rolling element set (126), further positions of the rolling element set (126) are determined in addition to the first position (PI) and the second position (P2) by means of the following method steps: Determining a first auxiliary position (HP1) of the rolling element set (126); after determining the first auxiliary position (HP1), rotating the first rolling bearing ring (122) relative to the second rolling bearing ring (124) according to the travel path; after rotating, determining a second auxiliary position (HP2) of the rolling element set (126); and wherein the expected position (E) is determined using the first auxiliary position (HP1), the second auxiliary position (HP2), and the first position (PI).
6. Method (100) according to one of the preceding claims, wherein the rolling component condition is determined as a function of a difference (D, D') between the second position (P2) and the expected position (E).
7. Method (100) according to one of claims 6, wherein the difference (D, D') is compared with a predefined limit value (G) and the rolling component state is determined depending on a result of this comparison.
8. The method (100) according to claim 7, wherein, during rotation, the first rolling bearing ring (122) is moved relative to the second rolling bearing ring (124) by a travel distance; and the limit value (G) is a relative limit value dependent on the travel distance.
9. Method (100) according to one of the preceding claims, wherein the determination of the first position (PI) and / or the second position (P2) of the rolling element set (126) is carried out by means of a measurement of an angle between a non-rotating fixed point (N) and the rolling element set (126).
10. Method (100) according to one of the preceding claims, wherein the determination of the first position (PI) and / or the second position (P2) of the rolling element set (126) is carried out by means of a measurement of a distance between a non-rotating fixed point and a rolling element (126.2AN) closest to the fixed point.
11. The method (100) according to claim 10, wherein a distance measuring unit (240A) is provided for measuring the distance, and a through hole (224.2A) is machined through one of the rolling bearing rings (224), in which the distance measuring unit (240A) is arranged.
12. The method (100) according to claim 11, wherein the rolling elements are formed as rolling balls, each having a rolling element center of gravity, wherein the rolling element centers of gravity move along a circular path when the rolling bearing rings rotate; and the through-hole (224.2A) has a longitudinal axis and is arranged within the one rolling bearing ring (224) such that a distance between an alignment of the through-hole along the longitudinal axis (224.2A.1) and the circular path (225A) at a point of closest approach is less than or equal to a radius of the rolling balls.
13. The method (100) according to claim 11, wherein the rolling elements are designed as rolling rollers (426A), each having a rotational axis (426A.1) and a rolling element side surface (426A.2) arranged perpendicular to the rotational axis (426A.1), and the through-hole (423A) is arranged within the one rolling bearing ring (422) such that, upon a relative movement of the rolling bearing rings (422, 424) to one another, the side surfaces (426A.2) of the rolling rollers (426A) roll past an opening (423A.2) of the through-hole (423A) and a center point of the opening (423A.2) is arranged outside a plane (425A) which is defined by the rotational axis (426A.1) and a velocity vector of a rolling element rolling past the opening (423A.2). Roller roller (426A) is clamped.
14. Rolling bearing assembly (500) for determining a rolling component condition of a rolling bearing (520), comprising: a rolling bearing (520) having a first rolling bearing ring (522), a second rolling bearing ring (524) and a rolling element set (526), wherein the first rolling bearing ring (522) is spaced from the second rolling bearing ring (524) by the rolling element set (526), and the rolling element set (526) comprises a rolling element cage (526.1) and a plurality of rolling elements (526.2AN) arranged within the rolling element cage (526.2), wherein each of the plurality of rolling elements (526.2AN) is in frictional contact with raceways (522.1, 524.1) the rolling bearing rings (522, 524); a control unit (570) which is designed to rotate the first rolling bearing ring (522) relative to the second rolling bearing ring (524); a position determination unit (540) which is designed to determine a first position of the rolling element set (526) before the first rolling bearing ring (522) rotates relative to the second rolling bearing ring (524) and to determine a second position of the rolling element set (526) after the rotation; an evaluation unit (560) which is designed to state as a function of the second position and an expected position which the rolling element set (526) would have had to reach starting from the first position in the case of an unchanged rolling component state and / or in the absence of rolling component damage; and an output unit (580) which is designed to output a state signal in Dependence of the determined rolling component condition.
15. Wind turbine (600) comprising a rolling bearing arrangement (500) according to claim 14.