JP7211852B2 - ROLLING BEARING CONDITION MONITORING DEVICE AND ROLLING BEARING CONDITION MONITORING METHOD - Google Patents

Description

The present invention relates to a rolling bearing condition monitoring device and a rolling bearing condition monitoring method.

Japanese Patent Laying-Open No. 2010-159710 (Patent Document 1) discloses a monitoring device that monitors the state of a main shaft bearing (rolling bearing) of a wind turbine generator. This monitoring device includes load detection means and determination means. The load detection means detects the applied load acting on the main shaft bearing. The judging means uses the detection signal of the load detecting means as one piece of judgment information to make a predetermined judgment regarding the main shaft bearing, for example, judgment of when maintenance is required.

According to this monitoring device, it is possible to accurately determine, for example, prediction of when maintenance is required for a main shaft bearing in a wind turbine generator (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2010-159710

Bearings (rolling bearings) that are not easy to replace and that are used under relatively low speed conditions, such as the main shaft bearings of wind power generators, are often used continuously even if damage occurs. For this reason, with regard to such bearings, it is an issue to predict when the bearings should be replaced according to the progress of damage.

For rolling bearings used at low speeds, even if the damage progresses, the vibration does not increase to the extent that the component parts of the device (for example, the gearbox connected to the main shaft in a wind power generator) are damaged. . However, as the damage progresses, if the relative displacement between the inner and outer rings (indicating the runout of the rotating ring with respect to the stationary ring) increases, the parts supported by the bearing will be displaced, resulting in an adverse effect. Abnormal contact between a part and its adjacent parts, poor meshing of gears, etc. can occur. For example, in the case of a wind power generator, an increase in the relative displacement between the inner and outer rings due to damage to the main shaft bearings can cause problems such as poor meshing of the gears of the speed increaser connected to the main shaft. Therefore, for rolling bearings used under low-speed conditions, such as the main shaft bearings of wind power generators, it is desirable to predict when to replace the bearings based on the relative displacement between the inner and outer rings.

Rolling bearings used under such low-speed conditions include bearings for wind power generators, bearings for tidal power generators, and bearings for large rolling rollers and guide rollers. be.

The permissible amount of relative displacement between the inner and outer rings, which is the basis for bearing replacement timing, can be determined based on the parts supported by the bearing. Therefore, it is not easy to determine the permissible amount of relative displacement between the inner and outer rings based on the parts supported by the bearing.

The monitoring device described in Patent Literature 1 is useful as a method for accurately predicting when maintenance is required for a main shaft bearing in a wind power generator. There is room for improvement in the accuracy of predicting the replacement timing of bearings that

The inventors of the present application conducted various studies and experiments on the progress of damage to rolling bearings in order to predict the timing of bearing replacement. proportionally.), the relative displacement between the inner and outer rings increases in stages, and from a predetermined stage, the relative displacement increases abruptly to the extent that it can affect the bearing support parts. As a result of further investigation, the inventors of the present application have obtained knowledge about the damage state and damage progression mechanism at each stage of the relative displacement that increases step by step with respect to damage to the rolling bearing.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a rolling bearing condition monitoring device and a condition monitoring method capable of predicting when to replace the bearing.

According to the present invention, the rolling bearing condition monitoring device has a plurality of rolling elements arranged at regular intervals in the circumferential direction between a rotating ring and a stationary ring, and is used under a radial load. It is a monitoring device. The rolling bearing condition monitoring device includes a damage detection unit that detects damage occurring in the center of the load area of the raceway surface of the stationary ring, and a damage detection unit that detects damage at a position spaced apart from the center of the load area in the circumferential direction by the above distance. and a predicting unit that predicts, as the replacement time, the time when new damage will occur due to the damage. The prediction unit calculates the first total number of loads until the damage detection unit detects damage, and the first maximum contact surface when contact surface pressure is generated between the rolling elements and the raceway surface at the center of the load range. the second maximum contact surface pressure when it is assumed that no contact surface pressure occurs between the rolling elements and the raceway surface at the center of the load range; The timing of replacement is predicted using the relationship with the second total load count until damage occurs at a position separated by a distance in the direction. The first maximum contact surface pressure and the second maximum contact surface pressure are both maximum contact surface pressures generated between the rolling elements and the raceway surface at positions spaced apart from the center of the load area in the circumferential direction.

Preferably, the prediction unit calculates the first maximum contact surface pressure and the second maximum contact surface pressure based on the first radial load applied to the rolling bearing. The prediction unit calculates a second radial load at which the maximum contact surface pressure generated between the rolling elements and the raceway surface at the center of the load range is the first maximum contact surface pressure. The prediction unit calculates a third radial load at which the maximum contact surface pressure generated between the rolling elements and the raceway surface at the center of the load range is the second maximum contact surface pressure. The prediction unit calculates a first basic rating life from the second radial load and the basic dynamic load rating of the rolling bearing. The prediction unit calculates a second basic rating life from the third radial load and the basic dynamic load rating of the rolling bearing. The prediction unit is a relational expression between the first total number of times of load, the first basic rating life, the second basic rating life, and the second total number of times of load of the rolling bearing from occurrence of damage to replacement time. is used to calculate the second total load number.

Preferably, the rolling bearing condition monitoring device is configured to monitor the condition of the main shaft bearing of the wind turbine generator. The rolling bearing condition monitoring device further includes a control section that controls the power generated by the wind power generator. If the replacement time predicted by the prediction unit is less than the desired replacement time, the control unit compares the generated power after the time when damage was detected by the damage detection unit with the generated power before that time. to suppress.

Preferably, the rolling bearing condition monitoring device is configured to monitor the condition of the main shaft bearing of the wind turbine generator. The rolling bearing condition monitoring device further includes a control section that controls the power generated by the wind power generator. If the replacement time predicted by the prediction unit is less than the desired replacement time, the control unit compares the generated power after the time when damage was detected by the damage detection unit with the generated power before that time. configured to suppress Based on the desired replacement timing, the control unit calculates a third total number of loads after the damage detection unit detects damage until damage occurs at a position spaced apart in the circumferential direction from the center of the load range; The third basic rating life is calculated using the relational expression among the total number of load cycles, the first basic rating life, and the third basic rating life. The control unit calculates a fourth radial load from the third basic rating life and the basic dynamic load rating of the rolling bearing. The control unit provides a fifth maximum contact surface pressure generated between the rolling elements and the raceway surface at the center of the load range when a fourth radial load is applied to the rolling bearing to a second maximum contact surface pressure. Calculate the radial load. The control unit uses a relationship prepared in advance between the radial load applied to the rolling bearing and the generated power to calculate the suppression rate of the generated power based on the fifth radial load. The control unit uses the suppression rate to suppress the power generation after the damage is detected by the damage detection unit.

Preferably, the rolling bearing condition monitoring device further includes a displacement detector for detecting relative displacement in the radial direction between the inner and outer rings of the rolling bearing. The damage detector detects occurrence of damage based on the relative displacement detected by the displacement detector.

Preferably, the displacement detector includes a displacement sensor that detects relative displacement.
Preferably, the displacement detection unit detects the measured value using a relationship prepared in advance between the measured value of at least one of the vibration acceleration of the rolling bearing, the sound produced by the rolling bearing, and the stress produced by the rolling bearing, and the relative displacement. indirectly detects the relative displacement based on .

According to the present invention, there is provided a rolling bearing condition monitoring method in which a plurality of rolling elements are arranged between a rotating ring and a stationary ring at regular intervals in the circumferential direction and are used under a radial load. state monitoring method. A method for monitoring the condition of a rolling bearing comprises a step of detecting damage occurring in the center of the load area of the raceway surface of a stationary ring, and a step of detecting damage at a position spaced apart from the center of the load area in the circumferential direction. and predicting the time when new damage will occur due to the above as the replacement time. The step of predicting is the first total number of loads until the damage is detected in the step of detecting damage, and the first total number of loads when contact surface pressure is generated between the rolling elements and the raceway surface at the center of the load range. The maximum contact surface pressure, the second maximum contact surface pressure when it is assumed that no contact surface pressure occurs between the rolling elements and the raceway surface in the center of the load range, and after the step of detecting damage detects damage, The timing of replacement is predicted using the relationship with the second total number of loads until damage occurs at a position spaced apart in the circumferential direction from the center of the load range. The first maximum contact surface pressure and the second maximum contact surface pressure are both maximum contact surface pressures generated between the rolling elements and the raceway surface at positions spaced apart from the center of the load area in the circumferential direction.

Preferably, the predicting step includes calculating the first maximum contact surface pressure and the second maximum contact surface pressure based on the first radial load applied to the rolling bearing. The predicting step includes a step of calculating a second radial load at which the maximum contact surface pressure generated between the rolling elements and the raceway surface at the center of the load range becomes the first maximum contact surface pressure. The predicting step includes a step of calculating a third radial load at which the maximum contact surface pressure generated between the rolling elements and the raceway surface at the center of the load range becomes the second maximum contact surface pressure. The predicting step includes calculating a first basic rating life from the second radial load and the basic dynamic load rating of the rolling bearing. The predicting step includes calculating a second basic rating life from the third radial load and the basic dynamic load rating of the rolling bearing. The prediction step is the relationship between the first total number of loads, the first basic rating life, the second basic rating life, and the second total number of loads of the rolling bearing from occurrence of damage to replacement time. and calculating a second total load number using the formula.

Preferably, the rolling bearing condition monitoring method is configured to monitor the condition of the main shaft bearing of the wind turbine generator, and further includes the step of controlling the power generated by the wind turbine generator. In the controlling step, when the replacement timing predicted by the predicting step is less than the desired replacement timing, the generated power after the time point when the damage is detected by the damage detecting step is replaced with the power generated before the time point. Suppression compared to generated power.

Preferably, the rolling bearing condition monitoring method is configured to monitor the condition of a main shaft bearing of a wind turbine generator. The rolling bearing condition monitoring method further includes controlling the power generated by the wind power generator. In the controlling step, if the replacement timing predicted by the predicting step is less than the desired replacement timing, the generated power after the time when the damage is detected by the damage detection unit is replaced with the generated power before that time. is configured to suppress relative to The step of controlling comprises: a third total number of loads after the damage detection unit detects damage until damage occurs at a position spaced apart in the circumferential direction from the center of the load range, based on the desired replacement timing; A step of calculating a third basic rating life using a relational expression of the first total number of loads, the first basic rating life, and the third basic rating life. The controlling step includes calculating a fourth radial load from the third basic rating life and the basic dynamic load rating of the rolling bearing. When the fourth radial load is applied to the rolling bearing, calculate the fifth radial load at which the maximum contact surface pressure generated between the rolling elements and the raceway surface at the center of the load range becomes the second maximum contact surface pressure. including the step of The controlling step includes a step of calculating a generated power suppression rate based on the fifth radial load, using a relationship prepared in advance between the radial load applied to the rolling bearing and the generated power. The controlling step includes using a curtailment rate to curtail the generated power after the damage is detected by the damage detecting step.

According to the present invention, it is possible to provide a rolling bearing condition monitoring device and a condition monitoring method capable of predicting when to replace the bearing.

BRIEF DESCRIPTION OF THE DRAWINGS It is the figure which showed together the sectional view of the rolling bearing monitored by the state-monitoring apparatus according to embodiment, and the block diagram of a state-monitoring apparatus. FIG. 4 is a diagram schematically showing a state of a rolling bearing near the center of a load range before initial damage occurs. FIG. 4 is a diagram schematically showing a state of a rolling bearing near the center of a load range after initial damage. FIG. 4 is a diagram showing an example of a damaged state near the center of the load range in stage 1; FIG. 10 is a diagram showing an example of a damaged state near the center of the load range in stage 2; FIG. 10 is a diagram showing an example of a damaged state near the center of the load range in stage 3; FIG. 10 is a diagram showing an example of a damaged state near the center of the load range in stage 3; It is the figure which showed the relationship between the number of rolling elements of no load, and relative displacement (delta)x between an inner ring and an outer ring. FIG. 4 is a diagram showing the relationship between the total number of times the inner ring receives loads from a plurality of rolling elements and the relative displacement δx between the inner and outer rings. FIG. 4 is a diagram showing the relationship between the radial load at the same rotational speed and the total number of loads until initial damage occurs. FIG. 4 is a diagram showing the relationship between radial load and remaining life at the same rotational speed; FIG. 5 is a diagram showing the relationship between the rotational speed and the total number of loads until the initial damage occurs under the same radial load. FIG. 4 is a diagram showing the relationship between rotational speed and remaining life under the same radial load. 4 is a flowchart for explaining a process of calculating the remaining life of a rolling bearing, which is executed by a prediction unit; 4 is a flowchart for explaining a process of calculating a basic rating life of a rolling bearing, which is executed by a predictor; It is a figure showing the relationship between the radial load and the maximum contact surface pressure calculated based on the Hertzian theory. It is a figure showing the relationship between the predicted value and measured value of remaining life. 1 is a diagram schematically showing the configuration of a wind power generator to which a rolling bearing condition monitoring device according to Embodiment 1 is applied; FIG. FIG. 4 is a diagram showing the relationship between the power generated by the wind power generator and the radial load; It is a block diagram showing the configuration of a state monitoring device according to Embodiment 2 of the present invention. 5 is a flowchart for explaining a process of calculating a suppression rate of generated power, which is executed by a power generation control unit; It is a figure which shows the relationship between the radial load (horizontal axis) and the maximum contact surface pressure (vertical axis) based on the Hertzian theory. FIG. 4 is a diagram showing the relationship between the control rate of the power generated by the wind power generator and the desired remaining life ratio. FIG. 4 is a diagram showing the relationship between the total number of times the inner ring receives loads from a plurality of rolling elements and the relative displacement between the inner and outer rings in a ball bearing.

Hereinafter, embodiments will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and detailed description thereof will not be repeated.

[Embodiment 1]
(Configuration of rolling bearing and condition monitoring device)
FIG. 1 is a cross-sectional view of a rolling bearing monitored by a condition monitoring device according to Embodiment 1 of the present invention, together with a block diagram of the condition monitoring device. In this first embodiment, a case where a rolling bearing is constituted by a roller bearing whose outer ring is a rotating ring will be described as a representative example, but the scope of application of the present invention is limited to such a bearing condition monitoring device. Rolling bearings to be monitored may have a rotating inner ring, or may be a ball bearing or the like.

Referring to FIG. 1 , rolling bearing 10 includes an inner ring 12 , an outer ring 16 and a plurality of rolling elements 18 . The inner ring 12 is fitted over a non-rotating shaft 14 . The outer ring 16 is provided on the outer peripheral side of the inner ring 12 and rotates integrally with a rotating body (not shown). Each of the plurality of rolling elements 18 is a cylindrical "roller" and is interposed between the inner ring 12 and the outer ring 16 while being held at equal intervals from adjacent rolling elements by a retainer (not shown).

The inner ring 12 receives a radial load from those of the plurality of rolling elements 18 that are passing through the load range. In this embodiment, a load area is formed vertically above the central axis of the inner ring 12, which is a stationary ring. In a normal state in which the raceway surface (the outer peripheral surface of the inner ring 12) is not damaged, the inner ring 12 passes through the center of the load area of the plurality of rolling elements 18 located vertically above the inner ring central axis. The maximum load is received from the rolling elements that are

A condition monitoring device 100 that monitors the condition of the rolling bearing 10 includes a displacement sensor 102, a rotation sensor 104, a damage detection section 106, and a prediction section . The displacement sensor 102 is a sensor for detecting relative displacement δ between the inner ring 12 and the outer ring 16 in the radial direction. The displacement sensor 102 is fixed to the shaft 14 or a solid structure that does not displace with respect to the shaft 14, and detects the displacement of the outer ring 16 (rotating ring) in the vertical direction X with respect to the inner ring 12 (stationary ring) to detect damage. Output to the detection unit 106 . Rotation sensor 104 detects rotational speed dN of rolling bearing 10 and outputs the detected value to prediction unit 108 . Note that the rotation sensor 104 may detect the rotational position of the rolling bearing 10, and the prediction unit 108 may calculate the rotational speed dN based on the detected value.

As described above, the inner ring 12 receives the maximum load from the rolling elements passing through the center of the load range in the normal state where the raceway surface is not damaged. Therefore, there is a high probability that initial damage will occur in the center of the load area. Damage detection unit 106 detects that initial damage has occurred in the center of the load range based on the detection value of displacement sensor 102 . Specifically, the damage detector 106 detects the maximum radial displacement δx (displacement in the X direction in FIG. 1 ) between the inner ring 12 and the outer ring 16 based on the detection value of the displacement sensor 102 . The relative displacement δ between the inner and outer rings detected by the displacement sensor 102 repeats minute fluctuations as the plurality of rolling elements 18 revolve. 16 or one revolution of the rolling elements 18) is the maximum value of the relative displacement δ. Hereinafter, this maximum displacement δx is simply referred to as "relative displacement δx between the inner and outer rings".

The damage detection unit 106 detects that damage has occurred in the center of the load range in response to the increase in the relative displacement δx between the inner and outer rings, and notifies the prediction unit 108 of the occurrence of damage in the center of the load range. .

In response to the notification from the damage detection unit 106, the prediction unit 108 predicts the time from the occurrence of the initial damage to the first occurrence of the "roller pitch damage" based on the gradual increase pattern of the relative displacement δx. The replacement time of the bearing 10 is predicted by calculating the total number of load times of . The total number of loads is the number of loads that the raceway surface receives each time each of the plurality of rolling elements 18 passes at an arbitrary point (for example, the center of the load area) in the circumferential direction of the raceway surface of the inner ring 12 (stationary ring). , since the rolling bearing 10 was put into use. The total number of load times is, in other words, the total number of times the plurality of rolling elements 18 pass through the inner ring 12, and the total number of load times TL is the total number of revolutions TR of the rolling bearing 10 (the number of times the outer ring has been rotated since the rolling bearing 10 was put into use). 16 (representing the total number of rotations of the rotating wheel)), it can be calculated by the following equation (1).

TL=TR×Nc/dN×number of rolling elements (1)
Here, Nc indicates the revolution speed of the center of the rolling element, and can be calculated from dN if the diameter of the rolling element 18 and the pitch circle diameter are known.

That is, the inventors of the present application conducted various studies and experiments on the progress of damage to rolling bearings, and as a result, the total number of times a stationary ring is subjected to a load from a plurality of rolling elements (total number of times a plurality of rolling elements pass through a stationary ring) The inventors have found that the relative displacement between the inner and outer rings increases step by step as . Further, the inventors of the present application have further obtained knowledge that such an increase pattern of relative displacement is caused by "roller pitch damage" described below occurring on the raceway surface of the stationary ring. The timing at which "roller pitch damage" first occurs on the raceway surface of the stationary ring is set as the timing for replacing the bearing 10.

Therefore, in the following, the occurrence mechanism of this "roller pitch damage" and the gradual increase pattern of the relative displacement δx according to the increase in the total number of loads applied to the inner ring 12, which is the stationary ring, will be described in detail.

(Description of roller pitch damage)
FIG. 2 is a diagram schematically showing the state of the rolling bearing 10 near the center of the load range before initial damage occurs. FIG. 3 is a diagram schematically showing the state of the rolling bearing 10 near the center of the load range after the occurrence of initial damage. "Initial damage" means damage that first occurs on the raceway surface of the inner ring 12 (stationary ring). This initial damage has a high probability of occurring in the center of the load range where the contact surface pressure between the plurality of rolling elements 18 and the raceway surface of the inner ring 12 (stationary ring) is maximum, and the initial damage also occurs in the center of the load range. It shall be.

In FIGS. 2 and 3, the vicinity of the center of the load area of the rolling bearing 10 is shown enlarged, and the raceway surface is drawn linearly for ease of illustration. Then, when one of the plurality of rolling elements 18 is passing through the center of the load range, the next rolling element that passes through the center of the load range, the rolling element that is currently passing through the center of the load range, and the load Rolling elements 18-1, 18-2, and 18-3 pass through the center of the zone.

Referring to FIG. 2, the maximum contact surface pressure between the rolling elements 18-2 passing through the center of the load range and the raceway surface of the inner ring 12 (stationary ring) is defined as the maximum contact surface pressure Pmax0. At this time, the maximum contact surface pressure between the rolling elements 18-1 and 18-3 adjacent to the rolling element 18-2 and the raceway surface of the inner ring 12 is defined as the maximum contact surface pressure Pmax1. The maximum contact surface pressure Pmax1 corresponds to "first maximum contact surface pressure". Before the initial damage occurs, the contact surface pressure between the rolling elements 18-2 and the raceway surface of the inner ring 12 while passing through the center of the load range is the maximum. Therefore, maximum contact surface pressure Pmax0>maximum contact surface pressure Pmax1 is.

Referring to FIG. 3, it is assumed that initial damage occurs on the raceway surface of inner ring 12 at the center of the load range where the contact surface pressure between the plurality of rolling elements 18 and the raceway surface of inner ring 12 is maximum. When the initial damage is expanded to a certain extent, the inner ring 12 receives almost no load from the rolling element 18-2 passing through the center of the load range (or the contact surface is larger than that of the adjacent rolling elements 18-1 and 18-3). pressure is sufficiently low, hereinafter also schematically referred to as the "no load" state) occurs.

When the rolling element 18-2 passing through the center of the load area is in an unloaded state, the load that should be received by the rolling element 18-2 is received by the other rolling elements. A large load is applied to the moving bodies 18-1 and 18-3. Furthermore, when the rolling element 18-2 passes through the initial damage portion, an inertial force is also generated due to the fluctuation of the outer ring 16 (rotating ring) with respect to the inner ring 12 (stationary ring).

In this way, after the occurrence of the initial damage, the rolling elements 18-1 and 18-3 adjacent to the rolling element 18-2 experience a decrease in the number of rolling elements receiving a load and a Due to the inertial force at the time, a larger contact surface pressure is generated than before the initial damage occurs. If the maximum contact surface pressure between the rolling elements 18-1 and 18-3 and the raceway surface of the inner ring 12 after the occurrence of initial damage is the maximum contact surface pressure Pmax2, the maximum contact surface pressure Pmax2>maximum contact surface pressure Pmax0 (>maximum contact is the surface pressure Pmax1). The maximum contact surface pressure Pmax2 corresponds to "second maximum contact surface pressure".

Therefore, when initial damage occurs in the center of the load range, each time the rolling elements pass through the initial damage area in the center of the load range, a large contact surface pressure (maximum contact The surface pressure Pmax2) is repeatedly generated, and new flaking occurs on the raceway surface of the inner ring 12 . Below, damage occurring at a position separated by a roller pitch from the initial damage portion is referred to as "roller pitch damage".

Once the roller pitch damage occurs, when the adjacent rolling elements pass through the roller pitch damage portion where the damage has progressed and the initial damage portion, a state of "no load" occurs at the same time. As a result, a larger contact surface pressure is repeatedly generated at a position further away from the roller pitch damage portion by the roller pitch, and the roller pitch damage progresses in a chain reaction and accelerated manner.

As the damage progresses as described above, the relative displacement δx between the inner and outer rings increases step by step. 4 to 7 are diagrams showing how damage occurring in the center of the load range progresses in the rolling bearing 10. FIG. In addition, in these figures, the vicinity of the load central region of the rolling bearing 10 is shown enlarged.

FIG. 4 is a diagram showing the state immediately after initial damage occurs at the center of the load. Initial damage is damage that first occurs on the raceway surface of the inner ring 12 (stationary ring). This initial damage has a high probability of occurring in the center of the load range where the contact surface pressure between the rolling elements 18 and the raceway surface of the inner ring 12 (stationary ring) is maximum. is shown for the case where

Referring to FIG. 4, initial damage (D1-1) occurs on the raceway surface of inner ring 12 at the center of the load range where the contact surface pressure between rolling elements 18 and raceway surface of inner ring 12 is maximum. Hereinafter, the state before the initial damage occurs in the center of the load range is referred to as "stage 0", and the state in which the initial damage occurs in the center of the load range (FIG. 4) is referred to as "stage 1".

FIG. 5 is a diagram showing a state in which the initial damage that occurs in the center of the load area spreads over the entire width direction of the raceway surface. Referring to FIG. 5, at the center of the load area where the initial damage occurred, if the damage (D1-2) expands in the circumferential direction of the raceway surface and expands over the entire width direction, the rolling elements 18 passing through the center of the load area is a state in which almost no load is applied (or a state in which the contact surface pressure is sufficiently smaller than that of the adjacent rolling elements, and hereinafter also roughly referred to as a "no-load" state). In the following, "Stage 2" refers to a state in which the rolling elements 18 passing through the center of the load range become "unloaded" as a result of the initial damage expanding across the width of the raceway surface in the center of the load range (Fig. 5). called.

FIG. 6 is a diagram showing a state in which the damage occurring in the center of the load area has further expanded in the circumferential direction of the raceway surface. Referring to FIG. 6, the damage that spreads across the entire width direction of the raceway surface at the center of the load range further spreads in the circumferential direction of the raceway surface (mainly in the downstream direction of movement of the rolling elements 18) (D1-3). As the damage progresses in the circumferential direction of the raceway surface, a situation occurs in which two adjacent rolling elements 18 enter the damaged portion at the same time. Hereinafter, the state in which the damage progresses in the circumferential direction of the raceway surface and the plurality of rolling elements 18 enter the damaged portion at the same time and the plurality of rolling elements 18 become "unloaded" is referred to as "stage 3".

As the damage progresses as described above, the relative displacement δx between the inner and outer rings increases step by step. That is, after the initial damage occurs in the center of the load range, the initial damage expands until the rolling elements 18 passing through the center of the load range enter a "no-load" state. The displacement δx increases (stage 1).

In the state (stage 2) where the rolling elements 18 passing through the center of the load range are "unloaded", the relative displacement δx between the inner and outer rings is larger than in stage 0 due to initial damage. However, until the damage expands in the circumferential direction of the raceway surface until the two adjacent rolling elements 18 enter the damaged portion at the same time, the relative displacement δx tends to increase with an increase in the total number of loads, as in stage 0. not shown.

Then, when the damage expands in the circumferential direction of the raceway surface until two adjacent rolling elements 18 enter the damaged portion at the same time, and a state occurs in which a plurality of rolling elements 18 become "no load" at the same time (stage 3), the load The relative displacement .delta.x between the inner and outer rings further increases due to the reduction in the number of rolling elements that receive the pressure.

Furthermore, when a plurality of rolling elements 18 are in the "unloaded" state at the same time (stage 3), the relative displacement δx between the inner and outer rings sharply increases. The reason for this is considered as follows. In other words, when the rolling elements 18 are in the "unloaded" state at the same time, the number of rolling elements that receive the load is further reduced, increasing the load that each rolling element 18 receives, and as a result, the speed at which damage progresses increases. . As a result, the relative displacement δx between the inner and outer rings sharply increases.

The state in which a plurality of rolling elements 18 are simultaneously "no load" is not limited to the case where the damage expands in the circumferential direction of the raceway surface until two adjacent rolling elements 18 enter the damaged portion at the same time. It can also occur when

FIG. 7 is a diagram showing how new flaking occurs at a position away from the initial damaged portion. Referring to FIG. 7, after the initial damage occurs, new flaking occurs at a position distant from the initial damage portion (D1), starting from an indentation generated on the raceway surface due to the biting of the peeled pieces of the damage. (D2). If the damage caused by this new flaking expands in the width direction of the raceway surface, a situation may occur in which a plurality of rolling elements 18 simultaneously enter the damaged portion caused by the new flaking and the initial damaged portion. In this case as well, the load received by each rolling element 18 increases due to the reduction in the number of rolling elements receiving the load, and as a result, the speed of damage progression increases.

An increase in the load received by each rolling element 18 also increases the inertial force due to the fluctuation of the rotating ring (outer ring 16) relative to the stationary ring (inner ring 12) when the rolling element 18 enters the damaged portion. , contributes to increasing the rate of damage growth from this point. For the reasons described above, when the plurality of rolling elements 18 are in a "no load" state at the same time (stage 3), the relative displacement δx between the inner and outer rings increases sharply.

In stage 3 as well, theoretically, after the two rolling elements 18 are in the "unloaded" state, the damage is further expanded, or new flaking occurs. Until the rolling element 18 reaches the "unloaded" state, a state may occur in which the relative displacement .delta.x does not show an increasing tendency as the total number of loads increases. However, in such a state, a large number of unloaded rolling elements 18 are generated, and the load received by the other rolling elements 18 is considerably increased. The inertia force generated in the body becomes considerable, and the damage progresses in a chain reaction and at an accelerated rate. As a result, when the rolling elements 18 pass through the damaged portion, the number of rolling elements that become unloaded at the same time increases at an accelerated rate, and the relative displacement δx between the inner and outer rings also increases at an accelerated rate.

FIG. 8 is a diagram showing the relationship between the number of rolling elements under no load and the relative displacement δx between the inner and outer rings. Since the relative displacement .delta.x is affected by the radial load, FIG. 8 shows the radial load divided into three stages.

Referring to FIG. 8, the horizontal axis indicates the number of rolling elements that become unloaded at the same time when the rolling elements pass through the damaged portion due to progress of roller pitch damage. The vertical axis indicates the relative displacement δx between the inner and outer rings. A circle indicates the case of a radial load of 90 kN, and a triangle indicates the case of a radial load of 70 kN. A square mark indicates the case where the radial load is 50 kN.

As shown in the figure, the relative displacement δx between the inner and outer rings accelerates as the number of unloaded rolling elements increases. As described above, once roller pitch damage occurs, the number of rolling elements that become unloaded at the roller pitch interval increases at an accelerated rate, and as a result, the relative displacement δx between the inner and outer rings increases at an accelerated rate. . That is, the increasing speed of the relative displacement δx on the stage 3 is very fast. Therefore, in the condition monitoring device according to the first embodiment, the timing at which stage 3 starts is set as the time to replace rolling bearing 10 .

FIG. 9 is a diagram showing an example of experimental results of examining the relationship between the total number of times the inner ring 12 receives loads from the plurality of rolling elements 18 and the relative displacement δx between the inner and outer rings. Fig. 9 shows that at a position away from the initial damage part, new flaking occurs starting from an indentation generated on the raceway surface due to the biting of the damaged flakes, and the damaged part caused by the new flaking. 1 shows experimental results in the case where a plurality of rolling elements 18 enter the initial damage portion and the initial damage portion at the same time. As experimental conditions, the rolling bearing 10 was a single-row cylindrical roller bearing with an inner diameter of 120 mm, an outer diameter of 215 mm, a width of 40 m, and a dynamic load rating of 260 kN. /min was given.

In FIG. 9, STG0 means stage 0, STG1 means stage 1, STG2 means stage 2, and STG3 means stage 3, respectively.

In the first embodiment, when the initial damage is detected, the total number of load times (hereinafter also referred to as "remaining life") from the time when the initial damage occurs to the time when the roller pitch damage occurs is calculated. By doing so, the replacement timing of the rolling bearing 10 is predicted. In FIG. 9, N1 is the total number of loads until initial damage occurs, and N2 is the total number of loads from the occurrence of initial damage to the occurrence of roller pitch damage. Since the duration of stage 1 is shorter than other stages, it is assumed that initial damage occurs at the start of stage 2 in this embodiment. Therefore, in FIG. 9, the remaining life is the total number of load times from the start of stage 2 to the start of stage 3, that is, N2. The total load number N1 corresponds to the "first total load number", and the total load number N2 corresponds to the "second total load number".

(Prediction of replacement time by prediction section)
FIG. 10 is a diagram showing the relationship between the radial load at the same rotational speed and the total number of loads until initial damage occurs. FIG. 11 is a diagram showing the relationship between radial load and remaining life at the same rotational speed.

10 and 11, as the radial load increases, both the total number of loading cycles until initial damage occurs and the remaining life decrease. That is, the radial load has a great influence on the replacement timing of the rolling bearing 10 .

FIG. 12 is a diagram showing the relationship between the rotational speed and the total number of loads until the initial damage occurs under the same radial load. FIG. 13 is a diagram showing the relationship between rotational speed and remaining life under the same radial load.

12 and 13, it can be seen that even if the rotation speed increases, the total number of load cycles until the occurrence of initial damage and the remaining life do not change much. That is, the rotational speed has little effect on the replacement timing of the rolling bearing 10 .

The reason why the radial load has a great influence on the replacement timing of the rolling bearing 10 is that the greater the radial load, the greater the contact surface pressure generated between the rolling elements 18 and the raceway surface in the load range. Therefore, in this embodiment, the radial load applied to the rolling bearing 10, the maximum contact surface pressure generated between the rolling element 18 and the raceway surface at a position separated from the center of the load range by the roller pitch, and the total Using the relationship of the number of loads, the remaining life of the position is calculated, and the replacement timing of the rolling bearing 10 is predicted.

It can be said that roller pitch damage is caused by the accumulation of rolling fatigue due to contact surface pressure repeatedly applied to the raceway surface from the rolling elements 18 at a position spaced apart by the roller pitch in the circumferential direction from the center of the load area. Also, the maximum contact surface pressure at that position differs greatly before and after initial damage occurs in the center of the load area. Therefore, the prediction unit 108 calculates the remaining life from the relational expression between the basic rating life before and after the initial damage occurs and the total number of loads according to the modified Miner's rule, which is a life prediction method for members that are repeatedly subjected to fluctuating stress. Predict when the bearing 10 should be replaced. Basic rating life is the substantial total number of revolutions that 90% (reliability 90%) can rotate without flaking due to rolling fatigue when a group of identical bearings are rotated individually under the same conditions. .

The basic rating life can be calculated from the radial load, but the basic rating life required for the calculation of the remaining life performed by the prediction unit 108 is related to the rolling fatigue at the position separated by the roller pitch in the circumferential direction from the center of the load range. It is. Therefore, the radial load is used when the maximum contact surface pressure at that position is applied to the center of the load area. That is, the prediction unit 108 obtains the maximum contact surface pressure before and after initial damage occurs in the center of the load range at a position separated from the center of the load range by the roller pitch from the radial load applied to the rolling bearing 10 . Back-calculate the radial loads before and after the initial damage occurs so that the maximum contact surface pressure occurs in the center of the load area. The basic rating life before and after the initial damage of the rolling bearing 10 occurs from the radial load, respectively.

Referring to FIG. 9 again, after damage occurs in the center of the load range, the relative displacement δx shows an increasing tendency as the total number of loading times increases, and when the total number of loading times reaches N1, the increasing tendency is shown. Gone. In this embodiment, it is assumed that damage occurs in the center of the load range at that time. The damage detection unit 106 detects that damage has occurred in the center of the load range at that time, and notifies the prediction unit 108 of the detection of the occurrence of the damage. Since the period during which the relative displacement δx exhibits the increasing tendency is relatively short, the time at which the damage detection unit 106 notifies the prediction unit 108 may be the time at which the relative displacement δx starts increasing.

The prediction unit 108 calculates the remaining life of the rolling bearing 10 according to the notification from the damage detection unit 106 . FIG. 14 is a flowchart for explaining the process of calculating the remaining life of the rolling bearing 10 executed by the prediction unit 108. As shown in FIG.

Referring to FIG. 14, prediction unit 108 determines whether or not damage detection unit 106 has notified in step S10 that damage has occurred in the center of the load range. If the notification has been received (YES in S10), prediction unit 108 advances the process to step S11. If there is no notification (NO in S10), prediction unit 108 returns the process to step S10.

In step S11, the prediction unit 108 calculates the total load count N1 until damage occurs in the center of the load range. The total number of loads that the inner ring 12 receives from the plurality of rolling elements 18 until damage occurs in the center of the load range is, in other words, the total number of times that the plurality of rolling elements 18 pass over the inner ring 12 until damage occurs in the center of the load range. be. The total number of times of load (that is, the total number of times the rolling elements 18 pass) N1 can be calculated by the following formula (2) based on the total number of rotations R1 of the rolling bearing 10 until damage occurs in the center of the load range. can.

N1=R1×Nc/dN×number of rolling elements (2)
In step S12, the prediction unit 108 calculates the basic rated life L1 derived in advance from the maximum contact pressure Pmax1, the basic rated life L2 derived in advance from the maximum contact pressure Pmax2, the total number of loads N1, and the remaining life N2. , the remaining life N2 is calculated from the relational expression (3) in the modified Miner's rule (see the expression (4), which is a modified version of the expression (3)).

N1/L1+N2/L2=1 (3)
N2=L2(1-N1/L1) (4)
Below, the processing for calculating the basic rated lives L1 and L2 required in step S12 will be described. FIG. 15 is a flowchart for explaining the process of calculating the basic rating life of the rolling bearing 10 (hereinafter also referred to as “bearing life calculation”) executed by the prediction unit 108 . Bearing life calculation can be performed once the specifications of the rolling bearing are determined. Therefore, it does not have to be performed immediately before prediction of replacement time by prediction unit 108, and may be performed at any time as long as it is performed prior to the prediction. Moreover, the bearing life calculation need not be performed by the prediction unit 108, and the prediction unit 108 may refer to the result of the bearing life calculation performed by another calculation entity.

The maximum contact surface pressure and radial load calculated in this bearing life calculation are calculated according to the Hertzian theory that the contact portion between the rolling element and the raceway surface is an elastic body and the other portion is a rigid body.

15, prediction unit 108 calculates maximum contact surface pressure Pmax1 and maximum contact surface pressure Pmax2 when actual radial load Fr0 is applied to rolling bearing 10 in step S110. Radial load Fr0 corresponds to the "first radial load". As described above, the maximum contact surface pressure Pmax1 is the maximum contact that occurs between the rolling elements 18 and the raceway surface of the inner ring 12 at positions separated from the center of the load area by the roller pitch in the circumferential direction before the initial damage occurs. It is surface pressure. As described above, the maximum contact surface pressure Pmax2 is the maximum contact that occurs between the rolling elements 18 and the raceway surface of the inner ring 12 at positions separated from the center of the load area by the roller pitch in the circumferential direction after the initial damage occurs. It is surface pressure.

In step S111, the prediction unit 108 calculates the radial load Fr1 at which the maximum contact pressure Pmax0 at the center of the load range becomes the maximum contact pressure Pmax1. The radial load Fr1 corresponds to the "second radial load". Furthermore, in step S112, prediction unit 108 calculates radial load Fr2 at which maximum contact pressure Pmax0 at the center of the load range becomes maximum contact pressure Pmax2. The radial load Fr2 corresponds to the "third radial load".

FIG. 16 is a diagram showing the relationship between the radial load (horizontal axis) and the maximum contact surface pressure (vertical axis) based on Hertzian theory. Using this figure, the processing performed in steps S110 to S112 of FIG. 15 will be visually explained.

Referring to FIG. 15 together with FIG. 16, curve S0 represents the relationship between radial load and maximum contact surface pressure Pmax0. A curve S1 represents the relationship between the radial load and the maximum contact surface pressure Pmax1. A curve S2 represents the relationship between the radial load and the maximum contact surface pressure Pmax2.

A point P1 on the curve S1 is a point on the curve S1 where the radial load is Fr0, and the maximum contact surface pressure at the point P1 is the maximum contact surface pressure Pmax1. A point P2 on the curve S2 is a point on the curve S2 where the radial load is Fr0, and the maximum contact surface pressure at the point P2 is Pmax2. These correspond to calculating the maximum contact surface pressure Pmax1 and the maximum contact surface pressure Pmax2 in step S110 of FIG.

A point P10 on the curve S0 is a point on the curve S0 where the maximum contact pressure Pmax0 is the maximum contact pressure Pmax1, and the radial load at the point P10 is Fr1. This corresponds to obtaining Fr1 in step S111 of FIG.

A point P20 on the curve S0 is a point on the curve S0 where the maximum contact pressure Pmax0 is the maximum contact pressure Pmax2, and the radial load at the point P20 is Fr2. This corresponds to obtaining Fr2 in step S112 of FIG.

Referring to FIG. 15 again, prediction unit 108 calculates basic rating life L1 of rolling bearing 10 when radial load Fr1 is applied from the following equation (5) (step S113). The basic rating life L1 corresponds to the "first basic rating life".

L1=(C/Fr1) ^10/3 (5)
C is the basic dynamic load rating. The basic dynamic load rating represents the dynamic load capacity of a rolling bearing, and refers to a constant load that gives a basic rated life of 1 million revolutions.

Prediction unit 108 calculates basic rating life L2 of rolling bearing 10 when radial load Fr2 is applied from the following equation (6) (step S114). The basic rating life L2 corresponds to the "second basic rating life".

L2=(C/Fr2) ^10/3 (5)
Through the above processing, the prediction unit 108 calculates the remaining life of the rolling bearing 10 and predicts the replacement timing of the rolling bearing 10 .

In the first embodiment, the maximum contact surface pressure and the radial load used in calculating the life of the bearing are calculated according to the Hertzian theory, but they may be calculated using other methods. For example, the finite element method (FEM) may be used to calculate all parts with elastic bodies or elastoplastic bodies. A method that considers dynamic effects by dynamic analysis may be used. The dynamics analysis is a method of establishing an equation of motion for each component of the rolling bearing 10 (the inner ring 12, the outer ring 16, and the rolling elements 18) and integrating the simultaneous ordinary differential equations along the time axis. It is also possible to obtain mode information of the entire condition monitoring device using theoretical mode analysis, introduce the mode information into dynamic analysis, and calculate by a method in which vibration characteristics are taken into account. Theoretical mode analysis is to mathematically determine what kind of vibration mode (eigenvalue information) a structure (elastic body) has.

FIG. 17 is a diagram showing the relationship between the predicted value of remaining life and the measured value. Referring to FIG. 17, there is a clear relationship between the predicted value of remaining life and the measured value, and it can be seen that the prediction of the replacement time performed by prediction unit 108 serves as an effective guideline. The measured value of the remaining life is about one order of magnitude shorter than the predicted value because flakes generated from the damaged part bite into the rolling elements, forming dents, and the contact surface pressure is concentrated near the dents. It is considered to be for The predicted value of remaining life may deviate from the actual remaining life due to external factors such as the influence of flakes. If the discrepancy is large, it is desirable to conduct experiments and analyzes that match the actual situation and correct the predicted value of the remaining life based on the results.

The rolling bearing condition monitoring device 100 described above can be applied to various mechanical devices, and is particularly suitable for monitoring the condition of a main shaft bearing of a wind turbine generator. That is, the main shaft bearings of wind power generators are not easy to replace, are used under relatively low speed conditions, and are often used continuously even if the bearings are damaged. As for the main shaft bearings of such wind turbine generators, it is a problem to predict when to replace the bearings due to damage. Therefore, a wind power generator to which condition monitoring device 100 according to the first embodiment is applied will be described below.

(Configuration of wind turbine generator)
FIG. 18 is a diagram schematically showing the configuration of a wind turbine generator to which the rolling bearing condition monitoring device according to the first embodiment is applied. Referring to FIG. 18, wind turbine generator 210 includes main shaft 220, blades 230, gearbox 240, generator 250, main shaft bearing (hereinafter simply referred to as "bearing") 260, and a displacement sensor. 270 and a data processor 280 . Gearbox 240 , generator 250 , bearings 260 , displacement sensor 270 and data processor 280 are housed in nacelle 290 , which is supported by tower 300 .

Main shaft 220 enters nacelle 290 , is connected to the input shaft of gearbox 240 , and is rotatably supported by bearing 260 . The main shaft 220 transmits the rotational torque generated by the blades 230 receiving the wind force to the input shaft of the gearbox 240 . Blade 230 is provided at the tip of main shaft 220 , converts wind power into rotational torque, and transmits the torque to main shaft 220 .

The gearbox 240 is provided between the main shaft 220 and the generator 250 to increase the rotation speed of the main shaft 220 and output it to the generator 250 . As an example, the speed increasing device 240 is configured by a gear speed increasing mechanism including a planetary gear, an intermediate shaft, a high speed shaft, and the like. It should be noted that, although not shown, a plurality of bearings for rotatably supporting a plurality of shafts are also provided inside the speed increaser 240 . Generator 250 is connected to the output shaft of speed increaser 240 and generates electric power by the rotational torque received from speed increaser 240 . Generator 250 is configured by, for example, an induction generator, but the type of generator 250 is not limited to this. Note that the generator 250 is also provided with bearings for rotatably supporting the rotor.

Bearing 260 is fixed within nacelle 290 and rotatably supports main shaft 220 . Bearing 260 is a rolling bearing and is a bearing to be monitored by the condition monitoring device according to this embodiment. It should be noted that this bearing 260 differs from the rolling bearing 10 described with reference to FIG. It is also applicable to bearings 260 such as When the outer ring is a stationary ring, the load area is vertically below the central axis of the outer ring, and initial damage and roller pitch damage are formed on the raceway surface of the inner peripheral surface of the outer ring.

Displacement sensor 270 is a sensor for detecting relative displacement between the inner and outer rings of bearing 260 . The displacement sensor 270 is fixed to the housing of the bearing 260 , detects a vertical displacement δx of the inner ring (rotating ring) with respect to the outer ring (stationary ring), and outputs it to the data processing device 280 .

A data processor 280 is provided within the nacelle 290 and receives detection values from the displacement sensor 270 . Then, data processing device 280 predicts the time to replace bearing 260 by calculating the remaining life of bearing 260 according to a preset program. This data processing device 280 implements the functions of the damage detection unit 106 and the prediction unit 108 described above.

As described above, in the first embodiment, the time to replace the rolling bearing can be predicted by calculating the remaining life.

[Embodiment 2]
In the above-described first embodiment, when the initial damage is detected, the total number of load cycles (remaining life) from the time when the initial damage occurs to the time when the roller pitch damage occurs is calculated. The configuration for predicting the time has been described.

Embodiment 2 describes a configuration for delaying the predicted replacement timing to the desired replacement timing. This configuration is applied when the calculated remaining life is less than the desired remaining life based on the desired replacement time. The desired replacement timing (desired remaining life) is determined by the target total power generation amount of the wind turbine generator (see FIG. 18) to which the rolling bearing condition monitoring device according to this embodiment is applied, and the rolling bearing replacement period. It can be set by referring to the securing of personnel and mechanical equipment for

FIG. 19 is a diagram showing the relationship between the power generated by the wind power generator and the radial load. Referring to FIG. 19, the horizontal axis indicates the radial load, and the vertical axis indicates the power generated by the wind power generator.

As shown in the figure, the radial load increases as the power generated by the wind power generator increases. As described with reference to FIG. 11, the remaining life becomes shorter as the radial load increases. That is, in the wind turbine generator, the generated power has a great influence on the remaining life.

Therefore, in the condition monitoring device according to the second embodiment, if the remaining life calculated when the initial damage is detected is less than the desired remaining life, the power generated by the wind power generator is suppressed. bottom. Since the radial load applied to the rolling bearing is also suppressed by suppressing the power generated by the wind power generator, the remaining life of the rolling bearing can be extended.

FIG. 20 is a block diagram showing the configuration of a condition monitoring device according to Embodiment 2 of the present invention. Condition monitoring device 100 according to the second embodiment monitors the condition of rolling bearing 10 in the same manner as condition monitoring device 100 according to the first embodiment shown in FIG. A condition monitoring device 100 according to the second embodiment is obtained by adding a power generation control unit 110 to the condition monitoring device 100 according to the first embodiment.

As described above, in response to the notification from the damage detection unit 106, the prediction unit 108 executes the processing shown in the flowchart of FIG. Calculate the total number of load cycles from the first occurrence of roller pitch damage).

The power generation control unit 110 is previously notified of the desired remaining life N3 of the rolling bearing 10 from a host control device (not shown). The desired remaining life N3 corresponds to the "third total number of loads". The power generation control unit 110 calculates the suppression rate of the power generated by the wind power generator based on the desired remaining life N3. The reduction rate of generated power refers to the ratio [%] of the amount of decrease in generated power to the generated power at the time when initial damage is detected. The power generation control unit 110 corresponds to an embodiment of the "control unit".

FIG. 21 is a flowchart for explaining the process of calculating the suppression rate of the generated power, which is executed by the power generation control unit 110 . The flowchart shown in FIG. 20 is obtained by adding the processes of steps S13 to S17 after the process of S12 of the flowchart shown in FIG.

In step S12, which is the same as in FIG. 14, when the remaining life N2 of the rolling bearing 10 is calculated by the prediction unit 108, in step S13, the power generation control unit 110 calculates the basic rated life L1 derived in advance from the maximum contact surface pressure Pmax1, Calculate the basic rating life L3 from the relational expression (6) in the modified Miner's rule of the total number of load times N1, the desired remaining life N3, and the basic rating life L3 (see formula (7), which is a modified version of formula (6). ).

N1/L1+N3/L3=1 (6)
L3=N3/(1-N1/L1) (7)
The calculated basic rating life L3 corresponds to the basic rating life of the rolling bearing 10 that can obtain the desired remaining life N3. The basic rating life L3 corresponds to the "third basic rating life". In step S14, power generation control unit 110 calculates radial load Fr3 applied to rolling bearing 10 to provide basic rated life L3 by performing reverse calculation of the bearing life calculation shown in FIG. The radial load Fr3 corresponds to the "fourth radial load". Specifically, power generation control unit 110 calculates radial load Fr3 from basic rated life L3 and basic dynamic load rating C of rolling bearing 10 using the following equation (8).

Fr3=C/L3 ^3/10 (8)
In step S15, the power generation control unit 110 calculates a radial load Fr4 at which the maximum contact pressure Pmax0 at the center of the load range when the actual radial load Fr3 is applied to the rolling bearing 10 becomes the maximum contact pressure Pmax2. As described above, the maximum contact surface pressure Pmax2 is the maximum contact that occurs between the rolling elements 18 and the raceway surface of the inner ring 12 at positions separated from the center of the load area by the roller pitch in the circumferential direction after the initial damage occurs. It is surface pressure.

FIG. 22 is a diagram showing the relationship between the radial load (horizontal axis) and the maximum contact surface pressure (vertical axis) based on Hertzian theory. Using this figure, the processing performed in step S15 of FIG. 21 will be visually explained.

Curves S0, S1 and S2 in FIG. 22 are the same as curves S0, S1 and S2 in FIG. A point P3 on the curve S0 is a point on the curve S0 where the radial load is Fr3, and the maximum contact surface pressure at the point P3 is the maximum contact surface pressure Pmax0.

A point P30 on the curve S2 is a point on the curve S2 where the maximum contact pressure is Pmax0, and the radial load at the point P30 is Fr4. This corresponds to obtaining Fr4 in step S15 of FIG. In other words, the radial load Fr4 corresponds to the radial load at which the maximum contact pressure Pmax0 at the center of the load range becomes the maximum contact pressure Pmax2 when the actual radial load Fr3 is applied. Radial load Fr4 corresponds to the "fifth radial load".

Referring to FIG. 21 again, in step S16, power generation control unit 110 controls the amount of power generated to load rolling bearing 10 with radial load Fr4 at which maximum contact pressure Pmax0 at the center of the load range becomes maximum contact pressure Pmax2. Calculate the suppression rate. Specifically, power generation control unit 110 calculates the power generated when radial load Fr4 is applied to rolling bearing 10 based on the relationship between the power generated by the wind power generator and the radial load shown in FIG. By preparing in advance a relational expression, a table, or the like representing the relationship between the generated power and the radial load shown in FIG. 19, the power generation control unit 110 can calculate the generated power when the radial load Fr4 is applied. can.

The power generation control unit 110 calculates the suppression rate of the generated power based on the calculated generated power and the generated power with respect to the generated power when the initial damage is detected. The suppression rate of the generated power can be expressed by (generated power at the time when the initial damage is detected--calculated generated power)/(generated power at the time when the initial damage is detected).

In step S17, the power generation control unit 110 suppresses the power generated by the wind turbine generator according to the calculated suppression rate of the power generation.

FIG. 23 is a diagram showing the relationship between the control rate of the power generated by the wind power generator and the desired remaining life ratio. In FIG. 23, the desired remaining life ratio is the ratio of the desired remaining life N3 to the remaining life N2 when the power generation control rate is 0%. Referring to FIG. 23, it can be seen that the desired remaining life ratio increases as the control rate of generated power increases. That is, by adjusting the control rate of the generated power, the remaining life can be adjusted, and as a result, the replacement timing of the rolling bearing 10 can be delayed until the desired timing.

As described above, in the second embodiment, the power generation suppression rate is calculated using the desired remaining life based on the desired replacement timing, and the power generation is suppressed according to this suppression rate. 10 replacement times can be delayed until the desired replacement time.

In the first and second embodiments described above, the rolling bearing 10 is assumed to be a roller bearing, but the present invention is similarly applicable to ball bearings.

FIG. 24 is a diagram showing the relationship between the total number of times the inner ring receives loads from a plurality of rolling elements and the relative displacement δx between the inner and outer rings in a ball bearing. Figure 24 corresponds to Figure 9 for the roller bearing. FIG. 24 shows the relationship between the total number of loads after the occurrence of initial damage in the center of the load range of the bearing and the relative displacement δx.

Referring to FIG. 24, similarly to the roller bearing, in the case of the ball bearing as well, by calculating the remaining life N12 from the time when the total number of loads reaches N11 to the start of stage 3, the replacement timing of the ball bearing can be determined. can be predicted.

In the case of a ball bearing, the calculation of the basic rating life L when a radial load Fr is applied in bearing life calculation is based on the following equation (9).

L=(C/Fr) ³ (9)
Also, in the case of the ball bearing, similarly to the roller bearing, the generated power is suppressed so that the radial load Fr4 calculated from the desired remaining life N3 is applied from the time when the total number of loads reaches N11. Therefore, the replacement timing of the ball bearing can be delayed until the desired replacement timing.

In the above description, the relative displacement δx between the inner and outer rings is measured by the displacement sensor 102 (270). A prearranged relationship between the relative displacement δx and the measured value of at least one of the stresses occurring in , may be used to indirectly detect the relative displacement δx based on previous measurements.

Furthermore, in the above description, the replacement timing of the bearing is predicted according to the change in the relative displacement δx between the inner and outer rings, but it may be determined according to other detected values. For example, the point in time when the bearing starts to vibrate abnormally from the state of normal vibration may be detected from the detection value of the acceleration sensor, and it may be assumed that damage occurred in the center of the load range at that point.

It is also planned to implement each embodiment disclosed this time in appropriate combination. And the embodiment disclosed this time should be considered as an illustration and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the description of the above-described embodiments, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

Reference Signs List 10,260 bearing, 12 inner ring, 14 shaft, 16 outer ring, 18 rolling element, 100 condition monitoring device, 102,270 displacement sensor, 104 rotation sensor, 106 damage detection unit, 108 prediction unit, 110 power generation control unit, 210 wind force Power generator, 220 main shaft, 230 blades, 240 gearbox, 250 generator, 280 data processor, 290 nacelle, 300 tower.

Claims (11)

A state monitoring device for a rolling bearing in which a plurality of rolling elements are arranged at regular intervals in the circumferential direction between a rotating ring and a stationary ring and used under radial load,
a damage detection unit that detects damage occurring in the center of the load area of the raceway surface of the stationary ring;
a prediction unit that predicts, as a replacement time, a time at which new damage will occur due to the damage detected by the damage detection unit at a position spaced apart in the circumferential direction from the center of the load range,
The prediction unit calculates a first total number of loads until the damage detection unit detects damage, and a first total number of loads when a contact surface pressure is generated between the rolling elements and the raceway surface at the center of the load range. , the second maximum contact surface pressure when no contact surface pressure is generated between the rolling elements and the raceway surface in the center of the load range, and the damage detection unit detects damage later predicting the replacement timing using a relationship with a second total number of loads until damage occurs at a position spaced apart in the circumferential direction from the center of the load range;
Both the first maximum contact surface pressure and the second maximum contact surface pressure are the maximum contact generated between the rolling elements and the raceway surface at a position spaced apart from the center of the load area in the circumferential direction by the distance. Condition monitoring device for rolling bearings, which is surface pressure. The prediction unit
calculating the first maximum contact surface pressure and the second maximum contact surface pressure based on the first radial load applied to the rolling bearing;
calculating a second radial load at which the maximum contact surface pressure generated between the rolling elements and the raceway surface in the center of the load range becomes the first maximum contact surface pressure;
calculating a third radial load at which the maximum contact surface pressure generated between the rolling elements and the raceway surface in the center of the load range becomes the second maximum contact surface pressure;
calculating a first basic rating life from the second radial load and the basic dynamic load rating of the rolling bearing;
calculating a second basic rating life from the third radial load and the basic dynamic load rating of the rolling bearing;
the first total load frequency, the first basic rating life, the second basic rating life, and the second total load frequency of the rolling bearing from the occurrence of the damage to the replacement time; 2. The rolling bearing condition monitoring device according to claim 1, wherein said second total load count is calculated using a relational expression. The rolling bearing condition monitoring device is configured to monitor the condition of the main shaft bearing of the wind turbine generator,
Further comprising a control unit for controlling the power generated by the wind turbine generator,
When the replacement timing predicted by the prediction unit is less than the desired replacement timing, the control unit reduces the generated power after the time point when damage is detected by the damage detection unit before the time point. 3. The rolling bearing condition monitoring device according to claim 1, wherein the generated power is suppressed in comparison with the generated power of the rolling bearing. The rolling bearing condition monitoring device is configured to monitor the condition of the main shaft bearing of the wind turbine generator,
Further comprising a control unit for controlling the power generated by the wind turbine generator,
When the replacement timing predicted by the prediction unit is less than the desired replacement timing, the control unit reduces the generated power after the time point when damage is detected by the damage detection unit before the time point. configured to be suppressed compared to the generated power of
The control unit
a third total load count from when the damage detector detects damage until damage occurs at a position spaced apart from the center of the load area in the circumferential direction by the distance, based on the desired replacement timing; calculating the third basic rating life using the relational expression among the first total number of loads, the first basic rating life, and the third basic rating life;
calculating a fourth radial load from the third basic rating life and the basic dynamic load rating of the rolling bearing;
When the fourth radial load is applied to the rolling bearing, the maximum contact surface pressure generated between the rolling elements and the raceway surface at the center of the load range becomes the second maximum contact surface pressure. Calculate the radial load of 5,
calculating a suppression rate of the generated power based on the fifth radial load using a relationship prepared in advance between the radial load applied to the rolling bearing and the generated power;
3. The rolling bearing condition monitoring device according to claim 2, wherein the power generation after the damage is detected by the damage detector is suppressed using the suppression rate. further comprising a displacement detection unit for detecting relative displacement in the radial direction between the inner and outer rings of the rolling bearing;
5. The rolling bearing condition monitoring device according to claim 1, wherein said damage detector detects occurrence of said damage based on the relative displacement detected by said displacement detector. 6. The rolling bearing condition monitoring device according to claim 5, wherein said displacement detector includes a displacement sensor for detecting said relative displacement. The displacement detection unit uses a relationship prepared in advance between a measured value of at least one of vibration acceleration of the rolling bearing, sound generated from the rolling bearing, and stress generated in the rolling bearing and the relative displacement, 7. The rolling bearing condition monitoring device according to claim 5, wherein said relative displacement is indirectly detected based on said measured value. A method for monitoring the condition of a rolling bearing in which a plurality of rolling elements are arranged at regular intervals in the circumferential direction between a rotating ring and a stationary ring and used under a radial load, comprising:
detecting damage occurring in the center of the load area of the raceway surface of the stationary ring;
Predicting, as a replacement time, a time at which new damage will occur due to the damage detected by the damage detection step at a position spaced apart in the circumferential direction from the center of the load range by the distance,
The step of predicting includes a first total load count until the step of detecting damage detects damage, and a contact surface pressure between the rolling elements and the raceway surface at the center of the load range. a first maximum contact surface pressure, a second maximum contact surface pressure when no contact surface pressure is generated between the rolling elements and the raceway surface at the center of the load range, and the step of detecting the damage predicts the replacement timing using a relationship with a second total number of loads until damage occurs at a position spaced apart in the circumferential direction from the center of the load range after the damage is detected,
Both the first maximum contact surface pressure and the second maximum contact surface pressure are the maximum contact generated between the rolling elements and the raceway surface at a position spaced apart from the center of the load area in the circumferential direction by the distance. A method for monitoring the condition of a rolling bearing, which is surface pressure. The predicting step includes:
calculating the first maximum contact surface pressure and the second maximum contact surface pressure based on a first radial load applied to the rolling bearing;
calculating a second radial load at which the maximum contact surface pressure generated between the rolling elements and the raceway surface in the center of the load range becomes the first maximum contact surface pressure;
calculating a third radial load at which the maximum contact surface pressure generated between the rolling elements and the raceway surface in the center of the load range becomes the second maximum contact surface pressure;
calculating a first basic rating life from the second radial load and the basic dynamic load rating of the rolling bearing;
calculating a second basic rating life from the third radial load and the basic dynamic load rating of the rolling bearing;
the first total load frequency, the first basic rating life, the second basic rating life, and the second total load frequency of the rolling bearing from the occurrence of the damage to the replacement time; 9. The rolling bearing condition monitoring method according to claim 8, further comprising the step of calculating said second total load count using a relational expression. The rolling bearing condition monitoring method is configured to monitor the condition of a main shaft bearing of a wind turbine generator,
further comprising controlling the power generated by the wind turbine generator;
In the controlling step, when the replacement timing predicted by the predicting step is less than the desired replacement timing, the generated power after the damage is detected by the damage detecting step is 10. The rolling bearing condition monitoring method according to claim 8 or 9, wherein the generated power is suppressed compared to the generated power before the time point. The rolling bearing condition monitoring method is configured to monitor the condition of a main shaft bearing of a wind turbine generator,
further comprising controlling the power generated by the wind turbine generator;
In the controlling step, when the replacement timing predicted by the predicting step is less than the desired replacement timing, the generated power after the damage is detected by the damage detecting step is is configured to be suppressed compared to the generated power before the point in time,
The controlling step includes:
a third total number of load times until damage occurs at a position spaced apart from the center of the load area in the circumferential direction by the distance after the step of detecting damage detects damage, based on the desired replacement timing; , calculating the third basic rating life using a relational expression among the first total number of loads, the first basic rating life, and the third basic rating life;
calculating a fourth radial load from the third basic rating life and the basic dynamic load rating of the rolling bearing;
When the fourth radial load is applied to the rolling bearing, the maximum contact surface pressure generated between the rolling elements and the raceway surface at the center of the load range becomes the second maximum contact surface pressure. calculating the radial load of 5;
calculating a suppression rate of the generated power based on the fifth radial load using a relationship prepared in advance between the radial load applied to the rolling bearing and the generated power;
10. The method of monitoring the state of a rolling bearing according to claim 9, further comprising the step of using the suppression rate to suppress the generated power after the damage is detected by the step of detecting the damage.

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