Rolling bearing condition monitoring system and condition monitoring method

Abstract

The present invention provides a condition monitoring system and a condition monitoring method that make it possible to detect signs of malfunction of a rolling bearing. A rolling bearing condition monitoring system according to the present invention comprises: a sensor (18) for monitoring the condition of a rolling bearing (17c) that is provided with a bearing outer ring (17c1) which is covered by a fixing member (17b) and a rod-shaped member (17e) which connects the fixing member (17b) and a bearing outer ring (17c1) together to prevent rotation of the bearing outer ring (17c1) with respect to the fixing member (17b), and for monitoring a physical quantity of the rod-shaped member (17e); and a condition monitoring device (62) for monitoring the condition of the rolling bearing (17c) on the basis of a change in the physical quantity acquired by the sensor (18).

Description

Condition monitoring system and condition monitoring method for rolling bearings

[0001] The present invention relates to a condition monitoring system and a condition monitoring method for detecting signs of a malfunction in a rolling bearing.

[0002] BACKGROUND ART Rolling bearings are used in machinery that supports rotating shafts, such as speed increasers for wind power generators and automobile transmissions.

[0003] Take a wind turbine generator as an example. Wind turbine generators are often installed in mountainous or coastal areas, making access for maintenance difficult. Furthermore, because wind turbine generators are large in structure, maintenance requires extensive crane work. For this reason, if a rolling bearing in the speed-increasing gearbox malfunctions, maintenance takes several days, and the wind turbine generator must be shut down for those several days.

[0004] Condition monitoring systems that detect signs of bearing problems are effective in reducing downtime of machinery.

[0005] Examples of problems that can occur in bearings include damage to the bearing, such as wear and flaking of the raceway surface, caused by bending loads that combine loads from multiple directions, excessive loads, and repeated loads. Such damage affects the operating accuracy of the bearing, and depending on the extent of the damage, may require the replacement of the part.

[0006] In order to prevent the above-mentioned situation from occurring, various methods have been devised for monitoring the condition of bearings in order to detect early signs of problems in rolling bearings.

[0007] Patent Document 1 describes a technology for observing the lubricating oil present between the outer ring of a bearing and the rolling elements and the lubrication state by generating ultrasonic waves toward the outer ring of a bearing from an ultrasonic probe attached to the bearing housing and measuring the reflected waves from the boundary between the outer ring of the bearing and the rolling elements.

[0008] Patent document 2 describes a sensor device that detects the load acting on a rolling bearing, and includes an ultrasonic sensor that measures changes in the contact area between a movable body and a fixed body that are in contact with each other using ultrasonic echoes, and processing means that determines the external load from the sensor output by utilizing the correlation between the external load and the contact area.

[0009] Patent Document 3 describes a method for monitoring the condition of a rolling bearing, in which an ultrasonic sensor attached to at least one of the outer ring, housing, inner ring, or shaft on which the inner ring is fitted of the rolling bearing generates ultrasonic waves toward the outer ring or inner ring, receives reflected waves from the boundary between the outer ring and rolling elements, the boundary between the outer ring and housing, the boundary between the inner ring and rolling elements, or the boundary between the inner ring and shaft, determines the measured number of revolutions of the rolling elements based on fluctuations in the echo height of the reflected waves, and compares this measured number of revolutions with the theoretical number of revolutions to monitor orbital slippage of the rolling bearing.

[0010] JP 2010-181237 A JP 2006-177933 A JP 2021-32769 A

[0011] A rolling bearing that supports a rotating shaft has a pin between the bearing housing or cover configured to cover the bearing outer ring and the bearing outer ring to prevent the bearing outer ring from rotating relative to the bearing housing or cover, i.e., a pin that has a rotation-preventing function for the bearing outer ring.

[0012] When a bearing is subjected to repeated structural deformation, for example, due to a bending load resulting from a combination of multi-directional loads or an unexpected excessive load, the pins naturally deform as well. If repeated sliding occurs between the pin and the hole in which it is attached due to pin deformation, the pin gradually wears out, creating a gap between the hole and the pin. This gap widens as the pin slides further between the hole and the hole, eventually causing the pin's anti-rotation function to be lost. When the pin's anti-rotation function is lost in this way, bearing creep may occur, in which the bearing outer ring rotates relative to the bearing housing or cover. Bearing creep causes wear at the contact surfaces between the bearing housing or cover and the bearing outer ring. This wear can cause the rotating shaft to misalign or tilt, potentially damaging the bearing itself.

[0013] For example, a gearbox for a wind turbine generator is configured to change speed in stages, thereby increasing the rotational speed of the main shaft to match the rotational speed of the generator. Such a gearbox is a machine that changes speed using multiple gear trains, and is equipped with rolling bearings on the rotating shaft that supports the gears.

[0014] Generally, multiple bearings support a shaft, each with its own role. For example, a fixed bearing for axial positioning is installed at one end of the supported shaft, and a free bearing is installed at the other end. In the free bearing, for example, the bearing outer ring and housing are loosely fitted, allowing the shaft expansion and contraction to be relieved along with the bearing. Free bearings may also be used separately for supporting radial loads and thrust loads, in which case the bearing for supporting thrust loads is loosely fitted. Bearing creep is naturally more likely to occur when the bearing outer ring and housing are loosely fitted. However, bearing creep can occur in both fixed and free bearings, depending on the bearing load support method and the load distribution within the machine.

[0015] Pin wear can have other effects on bearings as well. In machines where the oil that lubricates the gears and bearings circulates within the machine, a dust-collecting filter is attached to the oil piping system. However, depending on the equipment in which the bearings are installed, the filter may not be able to sufficiently remove the wear debris. For example, the gearboxes for wind turbine generators are permitted to pass through the filter with a diameter of less than 10 μm, which can result in the wear debris remaining inside the machine.

[0016] Under these conditions, rotating gears and bearings can become entrapped with foreign matter such as wear debris. When foreign matter gets caught on the raceway surface of a bearing, it creates an indentation on the raceway surface, which increases localized stress and shortens the bearing's lifespan. If the bearing continues to operate in this condition, it becomes more susceptible to fatigue damage such as pitting.

[0017] Wear of the pins that prevent the outer ring from rotating is considered to be a sign of bearing malfunctions, such as bearing creep, which causes the outer ring to rotate relative to the bearing housing or cover. However, conventional technology does not focus on the pins, making it difficult to prevent the loss of the anti-rotation function due to pin wear and making it difficult to effectively detect signs of bearing malfunctions. For example, in conventional bearings, pin wear is often already advanced by the time bearing creep is noticed. Therefore, there is a demand for devices and methods that can detect signs of rolling bearing malfunctions, particularly those caused by pin wear.

[0018] An object of the present invention is to provide a condition monitoring system and a condition monitoring method that can detect signs of a rolling bearing malfunction.

[0019] The rolling bearing condition monitoring system according to the present invention monitors the condition of a rolling bearing comprising a bearing outer ring covered by a fixed member and a rod-shaped member that connects the fixed member and the bearing outer ring to prevent the bearing outer ring from rotating relative to the fixed member, and comprises a sensor that monitors the physical quantity of the rod-shaped member, and a condition monitoring device that monitors the condition of the rolling bearing based on changes in the physical quantity acquired by the sensor.

[0020] A method for monitoring the condition of a rolling bearing according to the present invention monitors the condition of a rolling bearing comprising a bearing outer ring covered by a fixed member and a rod-shaped member that connects the fixed member and the bearing outer ring to prevent the bearing outer ring from rotating relative to the fixed member, and includes a measurement step of monitoring the physical quantity of the rod-shaped member with a sensor, and a condition monitoring step of monitoring the condition of the rolling bearing based on changes in the physical quantity acquired by the sensor.

[0021] According to the present invention, it is possible to provide a condition monitoring system and a condition monitoring method that can detect signs of a rolling bearing malfunction.

[0022] 1 is a side view of a wind turbine generator, showing a schematic cutaway view of the side of the wind turbine generator; FIG. 2 is a cross-sectional view of the speed-up gear, showing a schematic cutaway view of a portion of the secondary speed-up gear located at the rear upper part of the speed-up gear; FIG. 3 is a cross-sectional view of the speed-up gear, showing a schematic cutaway view of the periphery of the rearmost rolling bearing among the rolling bearings of the secondary speed-up gear shown in FIG. 2; FIG. 4 is a front view of the rolling bearing shown in FIG. 3, seen from a direction along the rotation axis; FIG. 5 is a cross-sectional view of the rolling bearing shown in FIG. 3, seen from above; FIG. 6 is a diagram showing the configuration of a condition monitoring system according to an embodiment of the present invention; FIG. 7 is a cross-sectional view of a portion of a rolling bearing, seen from the upper rear side, of a rolling bearing whose condition is monitored by a condition monitoring system according to an embodiment of the present invention; FIG. 8 is a side view of a detent pin, showing the pin in a state where no bending load is applied; FIG. 9 is a side view of a detent pin, showing the pin having undergone shear deformation due to a bending load being applied; FIG. 10 is a side view of a detent pin, showing the pin having worn and narrowed ends in the length direction; FIG. 11 is a side view of a detent pin, showing the pin having undergone bending deformation at the narrowed ends. 8B is a side view of a rotation-preventing pin, showing the pin with its end worn and shortened in length. FIG. 8A is an image of time history data of ultrasonic waves propagating through the pin shown in FIGS. 8A, 8B, and 8C. FIG. 8D is an image of time history data of ultrasonic waves propagating through the pin shown in FIG. 8E. FIG. 8C is an image of time history data of ultrasonic waves propagating through the pin when the pin alternates between the state shown in FIG. 8C and the state shown in FIG. 8D. FIG. 8E is an image of time history data of ultrasonic waves propagating through the pin when the pin alternates between the state shown in FIG. 8E and the state shown in FIG. 8D. FIG. 8C is a cross-sectional view of a part of a rolling bearing with a hollow pin, as seen from above. FIG. 8D is a cross-sectional view of a part of a rolling bearing with a hollow pin, as seen from above, in this embodiment. FIG. 8E is a cross-sectional view of a part of a rolling bearing with a hollow pin having a notched end, as seen from above. 1 is a cross-sectional view of a portion of a rolling bearing, seen from above, that includes a hollow pin having a notched end in this embodiment.

[0023] The rolling bearing condition monitoring system and condition monitoring method according to the present invention monitor the condition of a rolling bearing and can detect signs of a rolling bearing malfunction caused by wear of a rod-shaped member (e.g., a pin) that prevents the outer ring of the rolling bearing from rotating. Detecting signs of a rolling bearing malfunction can prevent the pin that prevents the outer ring from rotating from losing its anti-rotation function and bearing creep of the rolling bearing. Therefore, use of the present invention can reduce the downtime of machinery that uses rolling bearings.

[0024] A condition monitoring system and a condition monitoring method for a rolling bearing according to an embodiment of the present invention will be described below with reference to the drawings. Hereinafter, the extension direction of the shaft supported by the rolling bearing will be referred to as the axial direction, the rotation direction of this shaft will be referred to as the circumferential direction, and the radial direction of this shaft will be referred to as the radial direction. In the drawings used in this specification, identical or corresponding components will be designated by the same reference numerals, and repeated explanations of these components may be omitted.

[0025] <Wind turbine generator> First, an example of a mechanical device to which the rolling bearing condition monitoring system and condition monitoring method according to this embodiment are applied will be described. The condition monitoring system and condition monitoring method according to this embodiment can be applied to any device that includes a rolling bearing. Below, as an example, an example will be described in which the condition monitoring system and condition monitoring method according to this embodiment are applied to a gearbox of a wind turbine generator.

[0026] Fig. 1 is a side view of the wind turbine generator 11, showing a cutaway schematic side view of the wind turbine generator 11. The up-down direction in Fig. 1 is the up-down direction of the wind turbine generator 11. In Fig. 1, the left side is the front direction of the wind turbine generator 11, and the right side is the rear direction of the wind turbine generator 11.

[0027] The wind turbine generator 11 includes a nacelle 14 that is rotatable in a horizontal plane and is mounted on a support base 12. A main shaft 15 that extends in the fore-and-aft direction of the wind turbine generator 11 is provided within a casing of the nacelle 14.

[0028] The main shaft 15 is rotatably supported by a pair of front and rear main shaft bearings 1. One end (front end) of the main shaft 15 protrudes outside the casing of the nacelle 14 and is provided with a blade support base 16a. Blades 16 are rotatably mounted on the blade support base 16a. The other end (rear end) of the main shaft 15 is connected to a gearbox 17 as an input shaft. An output shaft 20 of the gearbox 17 is connected to a generator 19.

[0029] In addition to rotational torque, a bending moment due to wind force is generated on the main shaft 15. Although it depends on the structure of the wind power generator 11, the speed increaser 17 shares the reaction force generated on the main shaft 15.

[0030] <Gearbox> The gearbox 17 provided in the wind turbine generator 11 will be described.

[0031] The speed increaser 17 is a device that rotates the generator 19 while gradually increasing the rotational speed of the main shaft 15 therein. The speed increaser 17 includes a planetary gear mechanism as a primary speed increaser on the main shaft 15 side, and a secondary speed increaser on the generator 19 side.

[0032] The planetary gear mechanism has a structure in which multiple planetary gears are arranged on a carrier connected to the main shaft 15, and these planetary gears are meshed with an internally toothed ring gear and a sun gear, and the shaft integral with the sun gear is connected to a secondary speed increaser as the output shaft.

[0033] The secondary speed increaser transmits the rotation of the output shaft of the primary speed increaser to the generator 19 via multiple gear trains.

[0034] FIG. 2 is a cross-sectional view of the speed-increasing gear 17, showing a secondary speed-increasing gear located above and behind the speed-increasing gear 17, with a portion thereof cut away.

[0035] The speed increaser 17 includes a rotating shaft 17f and a rolling bearing 17c that supports the rotating shaft 17f.

[0036] The gear of the secondary speed-increasing gear of the speed-increasing gear 17 is supported by a rotating shaft 17 f. The rotating shaft 17 f is supported at both ends by a plurality of rolling bearings 17 c. The rolling bearing 17 c arranged at one end of the rotating shaft 17 f is used as a fixed-side bearing, and the rolling bearing 17 c arranged at the other end is used as a free-side bearing.

[0037] The speed increaser 17 includes a substantially annular housing 17a configured to cover the rolling bearing 17c. The housing 17a is a bearing housing and includes a front housing 17a1 and a rear housing 17a2. The speed increaser 17 further includes a substantially annular cover 17b configured to cover the rolling bearing 17c. The cover 17b includes a front cover 17b1 and a rear cover 17b2. The housing 17a and the cover 17b are fixing members that cover and fix the rolling bearing 17c. The housing 17a and the cover 17b have an integrated structure because their respective flange portions are fastened to each other with bolts.

[0038] Of the rolling bearings 17c, the free-side bearing has a clearance fit between the bearing outer ring and the housing 17a, and the expansion and contraction of the rotating shaft 17f is relieved together with the bearing. In a configuration in which the free-side bearing is divided into one for supporting radial (radial) loads and one for supporting thrust (axial) loads, it is common for the bearing for supporting thrust loads to have a clearance fit.

[0039] Typically, lubricating oil is supplied to the gears and bearings inside the housing 17a. The lubricating oil is circulated inside the machine by a circulation unit equipped with a pump and piping. If wear debris generated inside the machine for some reason circulates inside the machine along with the lubricating oil, and the gears and bearings become caught in this wear debris as foreign matter, fatigue damage such as pitting is likely to occur on the surfaces of the rolling parts.

[0040] In order to extend the life of the rolling parts and reduce the frequency of maintenance of the wind power generation device 11, an oil filter for collecting dust is arranged in the circulation section, and this oil filter removes wear particles.

[0041] The speed increaser 17 is provided with an oil seal 17d between the rotary shaft 17f and the cover 17b to prevent the lubricating oil from leaking to the outside.

[0042] <Rolling bearings> Rolling bearings include ball bearings and roller bearings, which differ in the shape of the rolling elements. A rolling bearing comprises a cylindrical inner ring arranged to cover the outer peripheral surface of a rotating shaft, and a cylindrical outer ring that covers the outer peripheral surface of the inner ring. The outer ring is arranged concentrically with the inner ring and is spaced a predetermined distance radially outward from the outer peripheral surface of the inner ring. A plurality of rolling elements are arranged circumferentially between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. Typically, a housing that covers the bearing is attached to the outer periphery of the outer ring.

[0043] Deep groove bearings are also used as rolling bearings. Deep groove bearings have a plurality of arc-shaped deep grooves formed at predetermined intervals in the circumferential direction on the outer peripheral surface of the inner ring, and a plurality of arc-shaped deep grooves formed on the inner peripheral surface of the outer ring at positions facing the deep grooves formed on the outer peripheral surface of the inner ring.

[0044] <Pin for preventing rotation of bearing outer ring> The rolling bearing 17c includes a pin 17e between the bearing outer ring and the housing 17a or cover 17b to prevent bearing creep, which is rotation of the bearing outer ring. The housing 17a and cover 17b are fixing members that cover and fix the bearing outer ring. The pin 17e is a rod-shaped member for preventing rotation of the bearing outer ring relative to the housing 17a or cover 17b, and is made of metal, for example. The pin 17e connects the bearing outer ring to the housing 17a or cover 17b, and fixes the bearing outer ring to the housing 17a or cover 17b, thereby preventing bearing creep.

[0045] Figure 3 is a cross-sectional view of the speed increaser 17, showing a schematic cutaway view of the area around the rearmost rolling bearing 17c (the rightmost one in Figure 2) of the rolling bearings 17c of the secondary speed increaser shown in Figure 2.

[0046] The rolling bearing 17c includes an outer ring 17c1, an inner ring 17c3, and a plurality of rolling elements 17c2 arranged between the outer ring 17c1 and the inner ring 17c3. In this embodiment, the rolling elements 17c2 are spherical elements (balls), but may also be cylindrical elements (rollers).

[0047] The bearing inner ring 17c3 is fixed to the rotating shaft 17f. In the example shown in Fig. 3, the bearing outer ring 17c1 is fixed to the cover 17b (front cover 17b1) of the gearbox 17. The cover 17b has a substantially annular shape, is installed concentrically with the bearing outer ring 17c1, and covers the bearing outer ring 17c1.

[0048] 3, pin 17e for preventing rotation of bearing outer ring 17c1 is installed between bearing outer ring 17c1 and cover 17b (rear cover 17b2) configured to cover bearing outer ring 17c1. As described above, pin 17e is a rod-shaped member for preventing bearing creep, and fixes bearing outer ring 17c1 to cover 17b to prevent bearing outer ring 17c1 from rotating relative to cover 17b.

[0049] Pin 17e is fixedly installed in a hole in cover 17b (or housing 17a) that covers bearing outer ring 17c1, and the portion that protrudes from cover 17b (or housing 17a) is inserted into the hole in bearing outer ring 17c1. Pin 17e is positioned in this manner to prevent bearing outer ring 17c1 from rotating relative to cover 17b, thereby preventing bearing creep.

[0050] Fig. 4 is a front view of the rolling bearing 17c shown in Fig. 3, seen from the direction along the rotation axis 17f. The rolling bearing 17c includes an outer bearing ring 17c1, an inner bearing ring 17c3, and a plurality of rolling elements 17c2.

[0051] Figure 4 shows an example of a pin 17e that is cylindrical, i.e., has a circular cross section perpendicular to the longitudinal direction and is solid. The cross section of the pin 17e may also have other shapes, such as a rectangle. Figure 4 also shows two pins 17e attached to the bearing outer ring 17c1. To ensure the anti-rotation function of the bearing outer ring 17c1 and to ensure the strength of the pins 17e, multiple pins 17e are usually attached to the bearing outer ring 17c1.

[0052] The pin 17e is also attached to the cover 17b (or the housing 17a). The hole in the cover 17b (or the housing 17a) for attaching the pin 17e can have any cross-sectional shape as long as the pin 17e can have a rotation-preventing function. For example, the cross-sectional shape of this hole can be circular or rectangular. In the example shown in FIG. 4, the cover 17b has a circular hole, and the pin 17e, which has a circular cross-sectional shape, is firmly fixed in this hole by interference fitting, press fitting, or the like.

[0053] 4, the outer ring 17c1 of the bearing fixed to the cover 17b of the gearbox 17 has a rectangular hole on its outer periphery. This hole is formed, for example, by cutting out the outer periphery of the outer ring 17c1 of the bearing.

[0054] As shown in Figure 3, when the flange surface of the rear cover 17b2 is aligned with the front cover 17b1 and the bearing outer ring 17c1, the pin 17e fixed to the rear cover 17b2 is inserted into a hole provided in the bearing outer ring 17c1, and the cover 17b and the bearing outer ring 17c1 form an integrated structure.

[0055] The hole in the bearing outer ring 17c1 can have any cross-sectional shape, such as rectangular or circular, as long as the pin 17e can be inserted therein. It is preferable that the pin 17e is also firmly fixed to the hole in the bearing outer ring 17c1. However, from the perspective of assembly, the pin 17e tends to be more loosely fixed to the hole in the bearing outer ring 17c1 than to the hole in the cover 17b (or housing 17a). Whether the pin 17e is more firmly fixed to the hole in the bearing outer ring 17c1 or the hole in the cover 17b (or housing 17a) can be determined based on, for example, whether the rolling bearing 17c is used as a fixed bearing or a free bearing, and the load support method of the rolling bearing 17c.

[0056] Figure 5 is a cross-sectional view of the rolling bearing 17c shown in Figure 3, viewed from above. The rolling bearing 17c includes a bearing outer ring 17c1, a plurality of rolling elements 17c2, and a bearing inner ring 17c3 (not shown in Figure 5). The bearing outer ring 17c1 is fixed to the cover 17b of the speed increaser 17. Figure 5 shows an end face of the rolling bearing 17c, an end face of the cover 17b (rear cover 17b2), and the mating surfaces of the cover 17b (rear cover 17b2) and the bearing outer ring 17c1 (see Figure 3).

[0057] 5, in the hole 17e1 of the bearing outer ring 17c1 in which the pin 17e is installed, there is an axial gap 17e2 between the pin 17e and the bearing outer ring 17c1. Also, in the hole 17b3 of the cover 17b in which the pin 17e is installed, there is an axial gap 17e3 between the pin 17e and the cover 17b.

[0058] 5 shows an example in which both the gap 17e2 and the gap 17e3 are present, but only one of the gaps 17e2 and 17e3 may be present, or neither may be present. From the viewpoint of firmly fixing the pin 17e to the holes 17e1 and 17b3 so as not to loosen, it is preferable that the gaps 17e2 and 17e3 are absent.

[0059] In this embodiment, an example will be described in which the pin 17e is disposed along the axial direction of the bearing outer ring 17c1, but the pin 17e may be disposed along the radial direction of the bearing outer ring 17c1.

[0060] <Example of embodiment of the present invention> A condition monitoring system and a condition monitoring method for a rolling bearing according to an example of the present invention will be described in detail.

[0061] Fig. 6 is a diagram showing the configuration of the condition monitoring system according to this embodiment. Fig. 6 also shows a cross-sectional view of a portion of the rolling bearing 17c, as seen from above, of the rolling bearing 17c whose condition is monitored by the condition monitoring system according to this embodiment. Fig. 7 is a cross-sectional view of a portion of the rolling bearing 17c, as seen from above and rearward, of the rolling bearing 17c whose condition is monitored by the condition monitoring system according to this embodiment.

[0062] The condition monitoring system according to this embodiment includes a sensor 18, a condition monitoring device 62, and a pin condition database 63, and monitors the condition of the rolling bearing 17c to detect signs of a malfunction of the rolling bearing 17c. The condition of the rolling bearing 17c refers to the presence or absence of a behavior in which the outer ring 17c1 of the rolling bearing 17c rotates relative to the housing 17a or cover 17b configured to cover the outer ring 17c1, i.e., the presence or absence of bearing creep. In this embodiment, the sensor 18 is an ultrasonic sensor and includes an ultrasonic device 61.

[0063] A pin 17e for preventing rotation of the outer ring 17c1 of the rolling bearing 17c is attached between the outer ring 17c1 of the rolling bearing 17c and the housing 17a or the cover 17b configured to cover the outer ring 17c1.

[0064] The sensor 18 is installed on one end surface of the pin 17e, which is a rod-shaped member, and monitors the physical quantity of the pin 17e. In this embodiment, the sensor 18 is an ultrasonic sensor installed in contact with one end surface of the pin 17e, irradiates ultrasonic waves from one end surface of the pin 17e toward the other end surface, and receives the ultrasonic waves reflected by the other end surface and returning. The physical quantity of the pin 17e is, for example, the length of the pin 17e. That is, in this embodiment, the sensor 18 measures and monitors the length of the pin 17e as the physical quantity of the pin 17e. The sensor 18 is rod-shaped (for example, approximately cylindrical) like the pin 17e. The diameter of the sensor 18 may be larger or smaller than the diameter of the pin 17e, or may be the same as the diameter of the pin 17e.

[0065] When multiple pins 17e are attached to the bearing outer ring 17c1, sensors 18 may be installed on all or some of the pins 17e. For example, sensors 18 may be installed only on pins 17e that are located in positions where symptoms of bearing creep can be easily detected. A position where symptoms of bearing creep can easily be detected is, for example, a position where the length of the pin 17e is likely to change.

[0066] The housing 17a and the cover 17b are provided with a hole 18b for installing a sensor 18 on one end surface of the pin 17e from the outside. The hole 18b opens to the outside of the housing 17a and the cover 17b. The sensor 18 is installed in the hole 18b and is installed on the pin 17e. When multiple pins 17e are attached to the bearing outer ring 17c1, it is preferable that multiple holes 18b corresponding to the multiple pins 17e are provided in the housing 17a and the cover 17b.

[0067] The sensor 18, which is an ultrasonic sensor, includes an ultrasonic device 61 and can measure and monitor the physical quantity, such as the length, of the pin 17e installed in the bearing outer ring 17c1. For example, the sensor 18, which is an ultrasonic sensor, can measure the physical quantity of the pin 17e installed in the bearing outer ring 17c1 while the rolling bearing 17c is in operation. The physical quantity of the pin 17e measured and acquired by the sensor 18 is transmitted to the condition monitoring device 62.

[0068] The ultrasonic device 61 determines the propagation time of the ultrasonic waves that are incident on the pin 17e from the sensor 18, are reflected, and return to the sensor 18, and determines the physical quantity of the pin 17e from this propagation time of the ultrasonic waves. Because the speed of sound of the ultrasonic waves that propagate inside the pin 17e is constant and can be determined in advance, the ultrasonic device 61 can determine the length of the pin 17e, which is the physical quantity of the pin 17e, from the propagation time of the ultrasonic waves and the speed of sound.

[0069] The condition monitoring device 62 monitors and diagnoses the condition of the rolling bearing 17c based on changes in the physical quantities of the pin 17e acquired by the sensor 18, and detects signs of malfunction of the rolling bearing 17c. The condition monitoring device 62 can be configured, for example, by a computer. In this embodiment, the condition monitoring device 62 determines the condition of the pin 17e from the propagation time of ultrasonic waves. For example, the condition monitoring device 62 can determine changes in the length of the pin 17e from changes in the propagation time of ultrasonic waves.

[0070] The pin status database 63 is a database that stores information about the relationship between the length of the pin 17e, the propagation time of ultrasonic waves, and the reception intensity (degree of ultrasonic wave attenuation). The pin status database 63 stores the relationship between the length of the pin 17e, the propagation time of ultrasonic waves, and the reception intensity in a normal state where no bearing creep is occurring. This relationship can be obtained in advance by conducting experiments or the like.

[0071] In this embodiment, by focusing on the physical quantity (length) of the pin 17e, it is possible to detect signs of bearing creep, in which the bearing outer ring 17c1 rotates relative to the housing 17a or the cover 17b, and to detect signs of a malfunction of the rolling bearing 17c. Specifically, the condition monitoring device 62 determines a change in the length of the pin 17e by comparing the propagation time of ultrasonic waves in a normal state stored in the pin condition database 63 with the propagation time of the measured ultrasonic waves, thereby detecting signs of a malfunction of the rolling bearing 17c. The condition monitoring device 62 may determine the change in the length of the pin 17e by comparing the length of the pin 17e determined from the propagation time of ultrasonic waves in a normal state with the length of the pin 17e determined from the propagation time of the measured ultrasonic waves.

[0072] In the wind turbine generator 11, when the gearbox 17 is configured to share the bending moment acting on the main shaft 15, the gearbox 17 shares not only the rotational torque but also the bending moment due to structural irregularities such as mounting errors, shape errors, excessive loads, eccentricity, etc. This bending moment acts as a bending load on the bearing of the gearbox 17. This bending load is also transmitted to the rear of the gearbox 17, and is also applied to the anti-rotation pin 17e of the bearing outer ring 17c1.

[0073] The pin 17e may be deformed by this bending load.

[0074] 8A to 8E are side views of the anti-rotation pin 17e and illustrate modified examples of the pin 17e. Also shown in Fig. 8A to 8E are sensor 18 attached to one end surface of the pin 17e, and the ultrasonic waves incident on the pin 17e, reflected from the sensor 18, and returned to the sensor 18 are indicated by dashed lines.

[0075] Fig. 8A is a diagram showing the pin 17e in a state where no bending load is applied, and shows the pin 17e in a normal state where no bearing creep has occurred.

[0076] 8B shows pin 17e undergoing shear deformation due to a bending load. When a small bending load is applied, pin 17e undergoes shear deformation while remaining integrated with bearing outer ring 17c1 and cover 17b (or housing 17a). When a large bending load is applied, pin 17e may move relative to hole 17e1 in bearing outer ring 17c1.

[0077] When a bending load is applied to the pin 17e, the pin 17e undergoes shear deformation and repeatedly moves relative to the hole 17e1 of the bearing outer ring 17c1, causing the longitudinal ends to gradually wear due to sliding against the hole 17e1 of the bearing outer ring 17c1.

[0078] Fig. 8C shows pin 17e in a state where no bending load is applied (no bending deformation occurs) after the longitudinal end portion has worn down and become thinner.

[0079] When the end of the pin 17e in the longitudinal direction wears down to a certain extent and becomes thinner, a gap is formed between the end and the hole 17e1 of the bearing outer ring 17c1, and this end undergoes bending deformation due to the bending load.

[0080] Depending on the mounting conditions of the bearing outer ring 17c1 and the cover 17b (or housing 17a), the end of the pin 17e on the bearing outer ring 17c1 side (the end inserted into the bearing outer ring 17c1) or the end on the cover 17b (or housing 17a) side may wear.

[0081] Fig. 8D shows pin 17e whose narrowed end has undergone bending deformation. Fig. 8D shows pin 17e whose end on the bearing outer ring 17c1 side has worn and undergone bending deformation, causing the end surface that reflects ultrasonic waves to be tilted at an angle θ.

[0082] If the wear at the end of the pin 17e continues to progress, the length of the pin 17e will become shorter, and eventually the pin 17e will lose its function of preventing rotation of the bearing outer ring 17c1.

[0083] Figure 8E shows pin 17e whose end has worn away and become shorter. For comparison, pin 17e (Figure 8A) in its normal state, where its length has not yet been shortened, is shown in dashed lines in Figure 8E. Before bearing creep occurs, as shown in Figure 8E, the length of pin 17e, which is a rod-shaped member, changes.

[0084] The ultrasonic device 61 determines the length of the pin 17e, which is a physical quantity of the pin 17e, from the propagation time and speed of sound of the ultrasonic waves.

[0085] 8A is the pin 17e in a state where no bending load is applied and no deformation is occurring, i.e., the pin 17e is in a normal state. The length of this pin 17e is defined as the reference length.

[0086] The pin 17e shown in Fig. 8B, which has been subjected to a bending load and has undergone shear deformation, has not changed in length.The pin 17e shown in Fig. 8C, which has been worn down and thinned at its end, also has not changed in length.

[0087] 8D, the length of pin 17e, whose narrowed end is bent, changes. For example, if pin 17e is bent while expanding, the length of pin 17e increases, and if pin 17e is bent while contracting, the length of pin 17e decreases. In this example, it is assumed that the length of pin 17e increases from the reference length due to bending deformation.

[0088] The pin 17e shown in Figure 8E has a shortened, worn end, resulting in a reduced length.

[0089] Fig. 9 is an image diagram of time history data of ultrasonic waves propagating through pin 17e shown in Fig. 8A, Fig. 8B, and Fig. 8C. As an example, Fig. 9 shows an example in which ultrasonic waves are emitted three times from sensor 18, and three pairs of incident waves and reflected waves are shown.

[0090] 8A, 8B, and 8C, the ultrasonic wave propagation time from incidence to reflection is the same for all three times. Furthermore, since the ultrasonic wave propagation times are the same for these pins 17e, it can be seen that the length has not changed from the reference length.

[0091] The propagation time of the ultrasonic waves in the pin 17e increases or decreases depending on the change in the length of the pin 17e due to bending or wear.

[0092] Fig. 10 is an image diagram of time history data of ultrasonic waves propagating through pin 17e shown in Fig. 8D. Fig. 10 shows an example in which ultrasonic waves are emitted three times from sensor 18, and three pairs of incident waves and reflected waves are shown. Fig. 10 also shows time history data of reflected waves from pin 17e shown in Fig. 8A (i.e., the waveform of the reflected wave shown in Fig. 9) as data of the original shape.

[0093] In the example shown in Fig. 10, the propagation time from ultrasonic wave incidence to reflection is the same for all three times, but is longer than the example shown in Fig. 9. In the pin 17e with a bent end shown in Fig. 8D, the end surface from which the ultrasonic wave is reflected is tilted by an angle θ due to bending deformation, and the ultrasonic wave is refracted and reflected at this end surface, lengthening the propagation time by the amount of refraction. Since the propagation time of the ultrasonic wave is longer, it can be seen that the length of pin 17e has changed and increased from the reference length.

[0094] Fig. 11 is an image diagram of time history data of ultrasonic waves propagating through pin 17e shown in Fig. 8E. As an example, Fig. 11 shows an example in which ultrasonic waves are emitted three times from sensor 18, and three pairs of incident waves and reflected waves are shown. Fig. 11 also shows time history data of reflected waves from pin 17e shown in Fig. 8A (i.e., the waveform of the reflected wave shown in Fig. 9) as data of the original shape.

[0095] In the example shown in Fig. 11, the propagation time from the incidence of the ultrasonic wave to its reflection is the same for all three times, but is shorter than the example shown in Fig. 9. The propagation time of the ultrasonic wave is shorter for pin 17e, whose end has become shorter due to wear, as shown in Fig. 8E. The shorter propagation time of the ultrasonic wave indicates that the length of pin 17e has changed and decreased from the reference length.

[0096] The condition monitoring device 62 can detect a change in the length of the pin 17e by using the relationship between the length of the pin 17e in a normal state and the propagation time of ultrasonic waves, which is stored in the pin condition database 63, and the propagation time of ultrasonic waves emitted from the sensor 18. If the length of the pin 17e has changed (particularly if the length of the pin 17e has decreased), the condition monitoring device 62 can detect this as a sign of a malfunction in the rolling bearing 17c.

[0097] Next, a description will be given of an example of a method for monitoring the state of the pin 17e by the state monitoring device 62. The state monitoring device 62 can monitor the state of the pin 17e by, for example, comparing the pin 17e in a loaded state, such as when the rolling bearing 17c is in operation, with the pin 17e in an unloaded state, such as when the rolling bearing 17c is not in operation.

[0098] Fig. 12 is an image diagram of time history data of ultrasonic waves propagating through pin 17e when pin 17e alternates between the state shown in Fig. 8C and the state shown in Fig. 8D. In the state shown in Fig. 8C, the worn and thinned end of pin 17e does not undergo bending deformation, but in the state shown in Fig. 8D, the worn and thinned end undergoes bending deformation. Fig. 12 also shows data of the original shape shown in Figs. 10 and 11.

[0099] In Fig. 12, during time periods A and C, no bending load is applied to pin 17e, and pin 17e is in an unloaded state and not bent, as shown in Fig. 8C. During time period B, a bending load is applied to pin 17e, and pin 17e is in a loaded state and bent, as shown in Fig. 8D. As shown in Fig. 12, pin 17e alternates between an unloaded state in which no bending load is applied and a loaded state in which a bending load is applied.

[0100] The ultrasonic wave propagation time is longer for the pin 17e (the pin 17e in a loaded state) in time period B than for the pin 17e (the pin 17e in an unloaded state) in time period A. The ultrasonic wave propagation times for the pin 17e (the pin 17e in an unloaded state) in time period A and time period C are equal to each other.

[0101] The state monitor 62 can distinguish between the loaded and unloaded states of the pin 17e from each other based on the difference in the propagation time of the ultrasonic waves.

[0102] Fig. 13 is an image diagram of time history data of ultrasonic waves propagating through pin 17e when pin 17e alternates between the state shown in Fig. 8E and the state shown in Fig. 8D. In the state shown in Fig. 8E, the end of pin 17e, which has become worn and shortened in length, does not undergo bending deformation, while in the state shown in Fig. 8D, the end undergoes bending deformation. However, in the explanation here, it is assumed that in the state shown in Fig. 8D, the end of pin 17e has become worn and shortened in length (i.e., it is assumed that pin 17e shown in Fig. 8E has undergone bending deformation). Fig. 13 also shows data of the original shape shown in Figs. 10 and 11.

[0103] In Fig. 13, during time periods D and F, no bending load is applied to pin 17e, and pin 17e is in an unloaded state and not bent, as shown in Fig. 8E. During time period E, a bending load is applied to pin 17e, and pin 17e is in a loaded state and bent, as shown in Fig. 8D. As shown in Fig. 13, pin 17e alternates between an unloaded state in which no bending load is applied and a loaded state in which a bending load is applied.

[0104] The ultrasonic wave propagation time is longer for the pin 17e in time period E (the pin 17e in a loaded state) than for the pin 17e in time period D (the pin 17e in an unloaded state). The ultrasonic wave propagation times for the pin 17e in time period D and time period F (the pin 17e in an unloaded state) are equal to each other and are shorter than the ultrasonic wave propagation time in the original shape data.

[0105] The state monitor 62 can distinguish between the loaded and unloaded states of the pin 17e from each other based on the difference in the propagation time of the ultrasonic waves.

[0106] Furthermore, the state monitoring device 62 can determine which of the states shown in Figures 8C to 8E the pin 17e is in based on the difference in propagation time of the ultrasonic waves as shown in Figures 12 and 13.

[0107] As described above, in this embodiment, the condition monitoring device 62 can detect signs of bearing creep occurring in the rolling bearing 17 c before it occurs from changes in the length and shape of the pin 17 e. By using an ultrasonic sensor as the sensor 18, changes in the length and shape of the pin 17 e can be detected from changes in the propagation time of ultrasonic waves in the pin 17 e.

[0108] In this embodiment, the condition monitoring device 62 not only detects signs of bearing creep, but also determines the condition of the pin 17e when or after the pin 17e is attached to the housing 17a or the cover 17b. For example, it is possible to determine whether the pin 17e is inserted straight into the hole 17e1 of the bearing outer ring 17c1 or whether it is inserted bent, based on the condition of the pin 17e as shown in Figures 8A to 8E.

[0109] For example, if pin 17e is inserted into hole 17e1 with its end bent as shown in Fig. 8D, depending on the angle θ at which the end face is tilted due to the bend, sensor 18 may not be able to properly receive the ultrasonic waves reflected from the end face, or the intensity of the ultrasonic waves received by sensor 18 may be weak. Also, for example, if the end of pin 17e inserted into hole 17e1 is worn, as shown in Fig. 8C or 8E, if the end of pin 17e is worn and the flat surface is lost, sensor 18 may not be able to properly receive the ultrasonic waves reflected from the end face, or the intensity of the ultrasonic waves received by sensor 18 may be weak.

[0110] In such a case, the state monitor 62 can determine the state of the pin 17e by referring to the data on the pin 17e in a normal state stored in the pin state database 63.

[0111] The pin condition database 63 can store information about the relationship between the length of the pin 17e, the propagation time of the ultrasonic waves, and the reception strength (degree of attenuation of the ultrasonic waves) even for pins 17e with bent ends or pins 17e with worn ends. The pin condition database 63 can also store this information in association with the operating time of the rolling bearing 17c.

[0112] Furthermore, by periodically removing the pin 17e from the rolling bearing 17c and inspecting it, and comparing the ultrasonic propagation time and reception strength with the data stored in the pin condition database 63 and the measured data, it is possible to determine whether the end of the pin 17e is bent, whether the end of the pin 17e is worn, whether the pin 17e is shortened, or a combination of these conditions.

[0113] In this embodiment, an example has been described in which the sensor 18 that monitors the physical quantity of the pin 17e is an ultrasonic sensor. The sensor 18 does not have to be an ultrasonic sensor, and may be, for example, a strain gauge or an FBG (Fiber Bragg Grating) sensor. Unlike an ultrasonic sensor, a strain gauge or an FBG sensor must be installed on the pin 17e by processing the pin 17e, such as by cutting or drilling a hole. Because an ultrasonic sensor can be installed on the pin 17e without such processing, the pin 17e on which the ultrasonic sensor is installed does not lose its rigidity against deformation, and the anti-rotation function for the bearing outer ring 17c1 is less impaired.

[0114] When installing a strain gauge or an FBG sensor on the pin 17 e, it is necessary to temporarily stop the operation of the rolling bearing 17 c. Furthermore, compared to ultrasonic sensors, strain gauges are more susceptible to deterioration due to environmental conditions, and are relatively susceptible to deterioration over time. Furthermore, once installed on the rolling bearing 17 c, it is difficult to attach or detach them from the rolling bearing 17 c.

[0115] When the ultrasonic sensor is attached to the pin 17e, it is preferable to apply liquid couplant to the end face of the pin 17e to promote the propagation of ultrasonic waves. After the rolling bearing 17c is put into operation, there is no need to temporarily stop the operation of the rolling bearing 17c when reapplying liquid couplant to the end face of the pin 17e.

[0116] Furthermore, when installing the ultrasonic sensor on the pin 17e, it is sufficient to simply press the ultrasonic sensor lightly against the end face of the pin 17e while fixing it. The ultrasonic sensor may remain fixed on the pin 17e for a long period of time, or may be removed from the pin 17e after a predetermined period of time has elapsed. When an ultrasonic sensor is used as the sensor 18, the length of the pin 17e can be easily determined from the propagation time of the ultrasonic waves, and changes in the length of the pin 17e can also be determined from changes in the propagation time.

[0117] The ultrasonic sensor is detachable from the rolling bearing 17c, and may be installed on the rolling bearing 17c at all times, or may be installed on the rolling bearing 17c only when necessary.

[0118] In the above description, the pin 17e is a cylindrical rod-shaped member that is solid. However, the pin 17e may be a hollow rod-shaped member.

[0119] FIG. 14 is a cross-sectional view of a part of the rolling bearing 17c, which is provided with a hollow pin 17e, as seen from above.

[0120] The pin 17e is a hollow rod-shaped member and has a hollow portion 17e4 extending in the longitudinal direction at the center of a cross section perpendicular to the longitudinal direction. The hollow portion 17e4 penetrates the pin 17e in the longitudinal direction. The sensor 18 that monitors the physical quantity of the pin 17e is an ultrasonic sensor. If the pin 17e is hollow and has the hollow portion 17e4, it is difficult to install an ultrasonic sensor on one end face of the pin 17e, and it is difficult to determine the change in the length of the pin 17e from the change in the propagation time of the ultrasonic waves.

[0121] In this embodiment, the hollow pin 17e has a solid rod-shaped member in the hollow portion 17e4, so that an ultrasonic sensor can be installed on one end surface of the pin 17e.

[0122] FIG. 15 is a cross-sectional view of a part of the rolling bearing 17c, which is provided with a hollow pin 17e in this embodiment, as seen from above.

[0123] The hollow pin 17e includes a solid rod-shaped member 17e5 in the hollow portion 17e4. The solid rod-shaped member 17e5 has substantially the same shape as the hollow portion 17e4 of the hollow pin 17e and is large enough to be installed in the hollow portion 17e4. The solid rod-shaped member 17e5 is preferably installed without any gaps in the hollow portion 17e4. The solid rod-shaped member 17e5 is made of, for example, metal and fixed to the hollow portion 17e4 by clearance fit, press fitting, adhesive, or welding. A sensor 18 (ultrasonic sensor) is installed on one end surface of the hollow pin 17e and the solid rod-shaped member 17e5, mainly on one end surface of the solid rod-shaped member 17e5.

[0124] In this embodiment, even though the pin 17e is hollow, an ultrasonic sensor can be attached to one end face of the pin 17e (particularly, one end face of the rod-shaped member 17e5), so that the change in the length of the pin 17e can be determined from the change in the propagation time of the ultrasonic waves. Furthermore, the hollow pin 17e having the rod-shaped member 17e5 in the hollow portion 17e4 has a double cylindrical structure, so that not only can an ultrasonic sensor be attached to one end face, but also the rigidity is improved, and the anti-rotation function with respect to the bearing outer ring 17c1 is strengthened.

[0125] The hollow pin 17e may have a notched end.

[0126] FIG. 16 is a cross-sectional view of a part of a rolling bearing 17c, seen from above, that includes a hollow pin 17e having a notched end.

[0127] The hollow pin 17e has a hollow portion 17e4 and a shape in which a surface perpendicular to the longitudinal direction is cut out at the end where ultrasonic waves are reflected. The sensor 18 that monitors the physical quantity of the pin 17e is an ultrasonic sensor. A hollow pin 17e with such a shape requires a surface that is parallel to the ultrasonic wave incident surface as an ultrasonic wave reflecting surface. Furthermore, as with the pin 17e shown in Figure 14, it is difficult to install an ultrasonic sensor on one end surface of the pin 17e, making it difficult to determine the change in the length of the pin 17e from the change in the ultrasonic wave propagation time.

[0128] FIG. 17 is a cross-sectional view of a part of a rolling bearing 17c, seen from above, which includes a hollow pin 17e having a notched end in this embodiment.

[0129] Hollow pin 17e, which has a notched end, includes solid rod-shaped member 17e5 in hollow portion 17e4. Solid rod-shaped member 17e5 has substantially the same shape as hollow portion 17e4 of hollow pin 17e, is made of metal, for example, and is fixed to hollow portion 17e4 by clearance fit, press fitting, adhesive, or welding. Sensor 18 (ultrasonic sensor) is installed on one end face of hollow pin 17e and solid rod-shaped member 17e5, mainly on one end face of solid rod-shaped member 17e5.

[0130] In this embodiment, even if the pin 17e is hollow and has a notched end, an ultrasonic sensor can be installed on one end face of the pin 17e (particularly on one end face of the rod-shaped member 17e5), so that the change in the length of the pin 17e can be determined from the change in the propagation time of the ultrasonic waves. Furthermore, the hollow pin 17e having the rod-shaped member 17e5 in the hollow portion 17e4 has a double cylindrical structure, so not only can an ultrasonic sensor be installed on one end face, but the rigidity is improved and the anti-rotation function with respect to the bearing outer ring 17c1 is strengthened.

[0131] As described above, the condition monitoring system and the condition monitoring method according to this embodiment can detect signs of a malfunction in the rolling bearing 17c.

[0132] <Other Examples of Embodiments of the Present Invention> In the above-described example, the rolling bearing 17c located at the rearmost position (the rightmost position in Fig. 2) among the rolling bearings 17c of the secondary gearbox shown in Fig. 2 has been described. This example can also be applied to other rolling bearings provided in the wind turbine generator 11. Furthermore, the rolling elements 17c2 (Fig. 3) provided in the rolling bearing 17c do not have to be spherical members (balls) and may be, for example, cylindrical members (rollers).

[0133] In the condition monitoring system and condition monitoring method according to this embodiment, the ultrasonic device 61 shown in Fig. 6 may be always connected to the sensor 18, or may be connected to the sensor 18 only when monitoring the condition of the rolling bearing 17c. The ultrasonic device 61 is portable, and may be transported and connected to the sensor 18.

[0134] In the embodiment described above, the pin 17e is inserted into the bearing outer ring 17c1 along the axial direction, but the pin 17e may also be inserted into the bearing outer ring 17c1 along the radial direction.

[0135] In the above embodiment, an example has been described in which the condition monitoring system and the condition monitoring method according to the present embodiment are applied to a gearbox of a wind turbine generator. This embodiment can be applied to condition monitoring of any rolling bearing 17c that has a pin 17e for preventing rotation of the bearing outer ring 17c1. For example, this embodiment can also be applied to rolling bearings provided in transmissions of construction machinery and ships, and rolling bearings provided in large machinery such as gas turbines and mixers.

[0136] It should be noted that the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to embodiments that include all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to delete part of the configuration of each embodiment, or to add or replace other configurations.

[0137] DESCRIPTION OF SYMBOLS 1...Main shaft bearing, 11...Wind turbine generator, 12...Support base, 14...Nacelle, 15...Main shaft, 16...Blade, 16a...Blade support base, 17...Gearbox, 17a...Housing, 17a1...Front housing, 17a2...Rear housing, 17b...Cover, 17b1...Front cover, 17b2...Rear cover, 17b3...Cover hole, 17c...Rolling bearing, 17c1...Bearing Outer ring, 17c2...rolling element, 17c3...bearing inner ring, 17d...oil seal, 17e...pin, 17e1...hole in bearing outer ring, 17e2...gap, 17e3...gap, 17e4...hollow portion, 17e5...solid rod-shaped member, 17f...rotating shaft, 18...sensor, 18b...hole portion, 19...generator, 20...output shaft, 61...ultrasonic device, 62...condition monitoring device, 63...pin condition database.

Claims

1. A condition monitoring system for a rolling bearing, comprising: a sensor that monitors the condition of a rolling bearing comprising a bearing outer ring covered by a fixed member and a rod-shaped member that connects the fixed member and the bearing outer ring to prevent the bearing outer ring from rotating relative to the fixed member; and a condition monitoring device that monitors the condition of the rolling bearing based on changes in the physical quantity obtained by the sensor.

2. The rolling bearing condition monitoring system according to claim 1, wherein the sensor measures the length of the rod-shaped member as the physical quantity.

3. A rolling bearing condition monitoring system according to claim 1, wherein the sensor is mounted on the rod-shaped member.

4. A rolling bearing condition monitoring system according to claim 1, wherein the sensor measures the physical quantity of the rod-shaped member when it is installed on the bearing outer ring.

5. A rolling bearing condition monitoring system according to claim 1, wherein the fixed member has a hole that opens to the outside of the fixed member, and the sensor is installed in the hole and is installed on the rod-shaped member.

6. The rolling bearing condition monitoring system according to claim 1, wherein the sensor is an ultrasonic sensor.

7. A rolling bearing condition monitoring system according to claim 1, wherein the rod-shaped member has a hollow portion extending in the longitudinal direction, the hollow portion contains a solid rod-shaped member, and the sensor is installed in the solid rod-shaped member.

8. A rolling bearing condition monitoring system according to claim 1, wherein the condition monitoring device monitors the condition of the rolling bearing provided in a gearbox of a wind turbine generator.

9. A method for monitoring the condition of a rolling bearing, comprising: a measurement step of monitoring the condition of a rolling bearing comprising a bearing outer ring covered by a fixed member and a rod-shaped member that connects the fixed member and the bearing outer ring to prevent the bearing outer ring from rotating relative to the fixed member; and a condition monitoring step of monitoring the condition of the rolling bearing based on changes in the physical quantity acquired by the sensor.

Images