Swivel mechanism anomaly diagnosis device and construction machinery

Abstract

To provide an abnormality diagnostic device for a swing device, and a construction machine, capable of reducing damage of a swing device pinion.SOLUTION: An abnormality diagnostic device for a swing device including a hydraulic motor 2, a planetary gear reducing mechanism 10 coupled to an output shaft 16 of a hydraulic motor, a pinion 17 provided in an output shaft 4 of the planetary gear reducing mechanism and engaged with internal teeth 18 of a swing bearing 80 in a grease bath 40, includes a first vibration sensor 8 attached to a reduction gear housing 6 as a housing of the planetary gear reducing mechanism, for detecting vibration of the reduction gear housing, and a processor 9a that determines the presence or absence of abnormality of the swing device on the basis of a detection result by a first vibration sensor. The processor subjects first vibration data acquired by the first vibration sensor to envelope processing and then converts the resultant data to a spectrum waveform, and calculates an RMS value of the spectrum waveform to determine a grease amount in the grease bath.SELECTED DRAWING: Figure 5

Description

【Technical Field】 【0001】 The present invention relates to an abnormality diagnosis device for a slewing device for construction machines such as hydraulic excavators, and a construction machine equipped with an abnormality diagnosis function. 【Background Art】 【0002】 A hydraulic excavator having a lower traveling body and an upper slewing body is provided with a slewing device for slewing the upper slewing body with respect to the lower traveling body. The slewing device includes a motor (for example, a hydraulic motor or an electric motor), a planetary gear reducer coupled to the output shaft of the motor, and a pinion (slewing device pinion) provided on the output shaft of the planetary gear reducer and meshing with the internal teeth of the slewing bearing in a grease bath. 【0003】 Among these, the planetary gear reducer is a device that decelerates the rotation input to the input shaft, amplifies the torque, and outputs it from the output shaft by a planetary gear mechanism composed of a plurality of gears. Regarding the abnormality diagnosis of the planetary gear reducer, a method of detecting the vibration generated in the vicinity of the planetary gear mechanism and determining the type, location, and degree of damage from the frequency of the vibration is known (for example, Patent Document 1). 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 8-043257 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 On the other hand, the slewing device pinion meshes with the internal teeth of the inner ring in a grease bath filled with grease. However, if the grease in the grease bath decreases due to continuous use and the oil level drops, the possibility of damage increases. If the slewing device pinion is damaged, a long downtime may occur. However, unlike the above-described planetary gear reducer, no abnormality diagnosis technology has been developed for the slewing device pinion. 【0006】 The object of the present invention is to provide a slewing device abnormality diagnosis device and construction machinery that can suppress damage to the slewing device pinion by determining the state of the grease in the grease bath. [Means for solving the problem] 【0007】 The present invention includes multiple means for solving the above problems, but to give one example, an abnormality diagnosis device for a slewing device comprising a motor, a planetary gear reducer coupled to the output shaft of the motor, and a pinion provided on the output shaft of the planetary gear reducer that meshes with the internal teeth of a slewing bearing in a grease bath, comprising a first vibration sensor attached to the reducer housing which is the housing of the planetary gear reducer and for detecting vibrations of the reducer housing, and a processor that determines whether or not there is an abnormality in the slewing device based on the detection result of the first vibration sensor, wherein the processor performs envelope processing on the first vibration data acquired by the first vibration sensor, converts the envelope-processed first vibration data into a spectral waveform, calculates the RMS value of the spectral waveform, When the RMS value is below a predetermined threshold, it is determined that the amount of grease in the grease bath has decreased to an amount that requires replenishment. Let's do it this way. [Effects of the Invention] 【0008】 According to the present invention, by determining the state (e.g., amount) of grease in the grease bath, it is possible to replenish or replace the grease at an appropriate time, thereby suppressing damage to the swivel pinion. [Brief explanation of the drawing] 【0009】 [Figure 1] A schematic diagram showing a side view of a hydraulic excavator according to an embodiment of the present invention. [Figure 2] This figure schematically shows the axial cross-section of the hydraulic motor 1 and planetary gear reducer 10 mounted on the hydraulic excavator shown in Figure 1. [Figure 3] Figure 2 shows a schematic cross-section of the planetary gear reducer 10. [Figure 4] A schematic plan view showing the area around the slewing bearing 80. [Figure 5] A diagram showing an example of a flowchart for abnormality diagnosis processing by controller 9. [Figure 6] This figure shows an example of a spectral waveform of vibration detected by a vibration sensor attached to the planetary gear reducer 10. [Figure 7] This diagram shows a specific example of how messages or images prompting grease replenishment in the grease bath 40 might be displayed, for example, on a monitor inside the cab. [Figure 8] This figure schematically shows the time evolution of acceleration RMS as an example of the time evolution of RMS value associated with the use of a hydraulic excavator. [Figure 9] This diagram shows an example of a flowchart for the abnormality diagnosis process performed by controller 9. [Figure 10] This figure shows an example of a spectral waveform of vibration detected by a vibration sensor attached to hydraulic motor 1. [Figure 11] This figure shows an example of the spectral waveform of vibration detected by a vibration sensor attached to the planetary gear reducer 10 (during abnormal conditions). [Figure 12] This figure shows an example of the spectral waveform of vibration detected by a vibration sensor attached to the planetary gear reducer 10 (under normal conditions). [Modes for carrying out the invention] 【0010】 Embodiments of the present invention will be described below with reference to the drawings. 【0011】 Figure 1 is a schematic side view showing the external appearance of a hydraulic excavator, which is an example of a construction machine according to this embodiment. In the following description, a hydraulic excavator equipped with a bucket as an attachment located at the tip of the front working device will be described, but the attachment can be replaced with various other items such as a grapple, breaker, or lifting magnet in addition to the bucket. 【0012】 The hydraulic excavator 100 shown in Fig. 1 includes a multi-joint front working device (working device) 30 in which a plurality of front members (boom 31, arm 33, bucket 35) that rotate vertically are connected in series, and an upper swing body 60 and a lower traveling body 70 that constitute the vehicle body. The upper swing body 60 is rotatably supported by the lower traveling body 2 via a swing bearing 80. The upper swing body 60 is configured by arranging each member on a swing frame 61, and the swing frame 61 that constitutes the upper swing body 60 is rotatable with respect to the lower traveling body 70. Further, the base end of the boom 31, which is the base end of the front working device 30, is rotatably attached to the front portion of the upper swing body 60 that constitutes the vehicle body, the base end of the arm 33 is rotatably supported by the tip of the boom 31, and the bucket 35 is rotatably supported by the tip of the arm 33. 【0013】 The lower traveling body 70 includes a pair of crawlers 71a (71b) wound around a pair of left and right crawler frames 72a (72b) respectively, and traveling hydraulic motors 73a (73b) that drive the crawlers 71a (71b) respectively, and supports the upper swing body 60 rotatably via a swing device 400. Regarding each configuration of the lower traveling body 70, only one of the pair of left and right configurations is illustrated and labeled, and the other configuration is only shown by the symbols in parentheses in the figure and the illustration is omitted. 【0014】 The boom 31, arm 33, bucket 35, and the lower traveling body 70 are respectively driven by boom cylinders 32, arm cylinders 34, bucket cylinders 36, which are hydraulic actuators, and the left and right traveling hydraulic motors 73a (73b). 【0015】 The upper swing body 60 is driven by a swing hydraulic motor 2 via a planetary gear reducer 10, and performs a rotational movement (swing operation) with respect to the lower traveling body 70. The planetary gear reducer 10 decelerates the rotation input from the output shaft 16 (see Fig. 2) of the swing hydraulic motor 2 while amplifying the torque and outputs it from the output shaft 4 (see Fig. 2). 【0016】 On the slewing frame 61 that constitutes the upper slewing body 60, there is a cab (driver's cab) 65 equipped with an operating device 45 for operating the front working device 30 (a plurality of front members 31, 32, 35), the upper slewing body 60, and the lower traveling body 70, and a controller 9 and the like that can perform abnormal diagnosis of the planetary gear reducer 10 are arranged. In addition to this, on the slewing frame 61, together with the engine 62 that is a prime mover, there is a hydraulic circuit system 41 including a hydraulic pump that supplies hydraulic oil to a plurality of hydraulic actuators such as the boom cylinder 32, the arm cylinder 34, the bucket cylinder 36, the slewing hydraulic motor 2, and the left and right traveling hydraulic motors 73a (73b). 【0017】 FIG. 2 is a schematic configuration diagram of the abnormality diagnosis device 300, the slewing device 400, and the slewing bearing 80 according to the present embodiment. 【0018】 The slewing device 400 includes a hydraulic motor (slewing hydraulic motor) 2, a planetary gear reducer 10 mechanically connected to the output shaft 16 of the hydraulic motor 2, and a pinion (slewing device pinion) 17 provided on the output shaft 4 of the planetary gear reducer 10 and meshing with the internal teeth 18 of the slewing bearing 80 in the grease bath 40. The planetary gear reducer 10 can be constituted by, for example, a two-stage planetary gear mechanism (the first planetary gear mechanism 3A, the second planetary gear mechanism 3B) connected in the axial direction, and the output shaft (rotation shaft) 16 of the hydraulic motor 2 is mechanically connected to the planetary gear reducer 10 (the sun gear 11a of the first planetary gear mechanism 3A in the illustrated example). 【0019】 The abnormality diagnosis device 300 includes a first vibration sensor 8 and a controller 9, and can determine whether or not there is an abnormality in the slewing device 400 based on the detection results from the first vibration sensor 8. Although the controller 9 shown in the figure is connected to the second vibration sensor 7, if the controller 9 is only used to determine whether or not the grease in the grease bath 40 needs to be replenished (i.e., whether the amount of grease has decreased to a level that requires replenishment) (in other words, if an abnormality diagnosis of the planetary gear reducer 10 is not performed), the second vibration sensor 7 can be omitted from the abnormality diagnosis device 300, and in that case, the mounting position of the first sensor 8 can be not only the housing 6 of the planetary gear reducer 10 shown in the figure, but also the housing 1 of the hydraulic motor 2. 【0020】 The slewing bearing 80 includes an inner ring 81 fixed to a frame 74 connecting the left and right crawler frames 72a and 72b of the lower traveling body 70 and having a plurality of internal teeth 18 on its inner circumference, and an outer ring 82 fixed to the lower surface of the slewing frame 61 and located on the outer circumference of the inner ring 81. 【0021】 A grease bath 40 is provided above the frame 74. The grease bath 40 is an annular recess provided along the inner surface of the inner ring 81, and houses the lower part of the pinion 17 immersed in grease (not shown). The outer circumferential surface of the grease bath 40 is composed of the inner circumferential surface of the inner ring 81, and it is preferable that the lower surface of the inner ring 81 and the grease bath 40 are liquid-tightly coupled. 【0022】 Figure 3 is a cross-sectional view of the planetary gear reducer 10 in the area where the first planetary gear mechanism 3A is located. The first planetary gear mechanism 3A includes a first sun gear 11a fixed to the output shaft (rotation shaft) 16 of the hydraulic motor 2, a plurality of first planetary gears 12a (three planetary gears 12a in the illustrated example) that mesh with the first sun gear 11a and can rotate while revolving around and rotating on the first sun gear 11a, a first internal gear 13a that meshes with the plurality of first planetary gears 12a and is fixed to the housing (reducer housing) 6 of the planetary gear reducer 10, a plurality of first planetary gear pins 14a inserted into the rotation center of the first planetary gear 12a, and a first carrier 15a fixed to the plurality of first planetary gear pins 14a and capable of rotating at the orbital speed of the first planetary gear 12a. 【0023】 The second planetary gear mechanism 3B includes a second sun gear 11b fixed to the first carrier 15a, a plurality of second planetary gears 12b that mesh with the second sun gear 11b and can rotate while revolving around and rotating on the second sun gear 11b, a second internal gear 13b that meshes with the plurality of second planetary gears 12b and is fixed to the housing 6, a plurality of second planetary gear pins 14b inserted into the rotational center of the second planetary gear 12b, and a second carrier 15b fixed to the plurality of second planetary gear pins 14b and can rotate at the orbital speed of the second planetary gear 12b. 【0024】 The second carrier 15b is connected to the output shaft 4 of the planetary gear reducer 10. Multiple bearings 5 ​​are provided around the output shaft 4 to support its rotation. A pinion (swivel pinion) 17 is provided at the lower end of the output shaft 4, which meshes with the internal teeth 18 of the inner ring 81 provided on the lower traveling body 70. 【0025】 Although the planetary gear mechanism of the planetary gear reducer 10 shown in the illustration has two stages, the number of stages in the planetary gear mechanism is not limited to this. 【0026】 In this embodiment, the housing 6 is a cylindrical component that covers multiple planetary gear mechanisms 3A, 3B and the output shaft 4, and multiple bearings 5 ​​are fixed between the housing 6 and the output shaft 4. 【0027】 The housing (motor housing) 1 of the hydraulic motor 2 is fixed to the upper part of the housing 6. For the hydraulic motor 2, for example, a radial type or an axial type piston motor can be used. In this embodiment, the housing 1 is a cylindrical part that covers the piston, cylinder block, and other components of the piston motor. 【0028】 In the illustrated example, the first vibration sensor 8 is mounted in the vicinity of the first planetary gear mechanism 3A in the housing 6 of the planetary gear reducer 10 (for example, on the outer circumference side of the first internal gear 13a). The first vibration sensor 8 is a sensor that detects vibrations occurring in the housing 6 of the planetary gear reducer 10, and for example, an acceleration sensor, a velocity sensor, or a contact-type displacement sensor can be used. In this embodiment, the first vibration sensor 8 is provided in contact with the outer wall of the housing 6, more specifically, the side surface (outside the side wall) of the housing 6. For example, the housing 8 is a cast part, and the first vibration sensor 8 includes a magnet (not shown) that can fix the first vibration sensor 8 to the housing 8. 【0029】 When determining whether grease needs to be replenished in the grease bath 40, it is preferable to mount the first vibration sensor 8 as close to the pinion 17 as possible. Furthermore, when diagnosing abnormalities in the planetary gear reducer 10, it is preferable to mount the first vibration sensor 8 in the range where gears are located inside the planetary gear reducer 10 in the axial direction, and more preferably as close as possible to the planetary gear mechanism to be diagnosed. In the example in Figure 2, it is mounted near the first planetary gear mechanism 3A. 【0030】 A second vibration sensor 7 can be attached to the housing 1 of the hydraulic motor 2. The second vibration sensor 7 is a sensor that detects vibrations occurring in the housing 1 of the hydraulic motor 2, and for example, an acceleration sensor, a velocity sensor, or a contact-type displacement sensor can be used. In this embodiment, the second vibration sensor 7 is provided in contact with the outer wall of the housing 1, more specifically the side surface (outside the side wall) of the housing 1. For example, the housing 1 is a cast part, and the second vibration sensor 7 includes a magnet (not shown) that can fix the second vibration sensor 7 to the housing 1. 【0031】 When diagnosing abnormalities in the planetary gear reducer 10, it is preferable to set the mounting position of the second vibration sensor 7 as far away from the first vibration sensor 8 as possible on the surface of the housing 1 so as not to be affected by vibrations generated by the planetary gear reducer 10. The second vibration sensor 7 may also be mounted on the top surface of the housing 1. 【0032】 The mounting positions and mounting methods for the first vibration sensor 8 and the second vibration sensor 7 described above are merely examples. For example, the first vibration sensor 8 or the second vibration sensor 7 can be fastened to the housing 6 or 1 with screws, or they can be attached with adhesive or the like. 【0033】 The first vibration sensor 8 and the second vibration sensor 7 are communicated with a controller 9 which includes a processor (e.g., CPU) 9a and a memory device (e.g., ROM, RAM) 9b. 【0034】 The connection between the first vibration sensor 8 and the second vibration sensor 7 and the controller 9 may be a wired connection using a communication cable or the like, or a wireless connection. The controller 9 may be a computer or microcomputer, or a monitor that displays the waveform of vibration data and diagnostic results may be connected to the controller 9. If the inputs from the first vibration sensor 8 and the second vibration sensor 7 are analog signals, an AD converter that converts the analog signals to digital signals may be installed in the controller 9. In other words, the abnormality diagnosis device 300 may have, for example, a monitor (for example, monitors 91, 92, 93 described later) connected to the controller 9 that displays the diagnostic results and diagnostic details. 【0035】 The vibration data used by controller 9 for anomaly diagnosis consists of data measured simultaneously by both the first vibration sensor 8 and the second vibration sensor 7. That is, the start and end times of measurement for the vibration data from each sensor 8 and 7 used for anomaly diagnosis coincide. For example, the vibration data is sampled over several seconds to several tens of seconds at frequencies ranging from a few kHz to tens of kHz. 【0036】 Figure 4 is a schematic plan view of the area around the slewing bearing 80. The slewing bearing 80 comprises an inner ring 81 fixed to the lower traveling body 70 and an outer ring 82 positioned on the outer circumference of the inner ring 81 and fixed to the upper slewing body 60. Multiple balls (not shown) are housed between the inner ring 81 and the outer ring 82 along the circumferential direction. 【0037】 The pinion 17 meshes with the internal teeth 18 of the inner ring 81. A grease bath 40, which is an annular recess, is located on the inner circumference of the inner ring 81, and the pinion 17 is immersed in the grease in the grease bath 40. By ensuring that the grease bath 40 is filled with grease, damage to the pinion 17 and the internal teeth 18 of the inner ring 81 is prevented. 【0038】 When rotational torque from the hydraulic motor 2 is applied to the pinion 17, the pinion 17 revolves along the inner circumference of the inner ring 81 while meshing with the internal teeth 18, and the outer ring 82 rotates on the outer circumference side of the inner ring 81 as the pinion 17 moves. As a result, the upper slewing body 60 rotates relative to the lower traveling body 70. 【0039】 Figure 5 shows an example of a flowchart of the abnormality diagnosis process performed by the controller 9. The controller 9 executes the process shown in Figure 5 based on the program stored in the memory device and the vibration data acquired via the first vibration sensor 8. 【0040】 First, in step 221, the controller 9 acquires first vibration data related to the planetary gear reducer 10, which is obtained via the first vibration sensor 8. 【0041】 Next, in step 222, the controller 9 performs envelope processing (envelope processing) on ​​the first vibration data acquired in step 221 to extract the outline of its amplitude. 【0042】 Then, in step 223, the controller 9 converts the first vibration data after envelope processing into a spectral waveform using a Fast Fourier Transform (FFT). Figure 6 shows an example of a spectral waveform obtained from the first vibration data in step 223. 【0043】 The spectral waveform in Figure 6 shows an example where the first sun gear 11a is damaged. The figure shows a peak at the peak frequency Fm of the hydraulic motor 2 (the peak frequency Fm can be calculated, for example, in the process described later in step 203), and two peaks that occurred at the characteristic frequency fds and its integer multiple frequency 2fds due to the damage to the first sun gear 11a. Note that when there is no damage to any gear (i.e., under normal conditions), no peaks are observed at the characteristic frequency fd and its integer multiple frequency nfd. 【0044】 In Figure 6, Fth indicates a predetermined threshold value (frequency threshold) related to the frequency of the spectral waveform. For example, 50 Hz can be selected as Fth. 【0045】 In step 224, the controller 9 calculates the RMS value of the spectral waveform obtained in step 223. The RMS value is the square root of the mean of the squared values ​​of the signal and is also called the effective value. It is preferable to calculate the RMS value in the region below the frequency threshold Fth (referred to as the "low frequency region"). If the first vibration data was acquired by an acceleration sensor, the RMS value will be the acceleration RMS value. 【0046】 In step 225, the controller 9 performs a grease condition diagnosis step that compares the RMS value calculated in step 224 with a predetermined threshold Vth. If the RMS value is less than the threshold Vth, it determines in step 226 that there is an abnormality (the amount of grease remaining in the grease bath 40 is low). If the RMS value is equal to or greater than the threshold Vth, it determines in step 227 that there is no abnormality (the amount of grease in the grease bath 40 is sufficient). 【0047】 In step 226, a notification device such as a monitor installed in the cab of the hydraulic excavator may prompt the operator to replenish the grease in the grease bath 40. Figure 7 shows a specific example of displaying a message or graphic prompting the operator to replenish the grease in the grease bath 40, for example, on a monitor in the cab. Monitor 91 in the figure is a monitor for a medium-sized hydraulic excavator, and monitors 92 and 93 are monitors for extra-large hydraulic excavators used in mines, etc. Each monitor 91, 92, and 93 displays a message 94 indicating that the oil level in the grease bath 40 is low and needs to be replenished, a graphic 95 indicating that there is a problem with the hydraulic excavator, and an OK button 96 which is pressed by the operator after they have seen the message or graphic, and which acts as a trigger to hide the message or graphic. 【0048】 (Effects / Actions) The operation and effects of this embodiment will be explained with reference to Figure 8. Figure 8 is a schematic diagram showing the time change of acceleration RMS as an example of the time change of RMS value associated with the use of a hydraulic excavator. First, immediately after the start of use of the hydraulic excavator, the measured acceleration RMS is relatively high. This is thought to be because the grease bath 40 is filled with grease, and when the pinion 17 rotates and pushes its way through the grease as it revolves within the grease bath 40, it receives a large resistance from the grease, and vibration components in the high-frequency range, such as collision excitation, are randomly generated. Furthermore, as the use of the hydraulic excavator continues, the measured acceleration RMS gradually decreases. This is thought to be because, as the hydraulic excavator is used over a long period of time and the grease is consumed, the oil level (amount of grease) in the grease bath 40 decreases, resulting in less resistance when the pinion 17 revolves and a reduction in vibration components. Unlike the grease bath method in which the pinion 17 is immersed in grease, as in this embodiment, the grease method in which grease is applied to the gear exhibits the opposite phenomenon to that of the present invention: as the amount of grease decreases, the oil film thins, the gear surface becomes rough, and the acceleration RMS is amplified. 【0049】 Based on these findings, the inventors have configured the abnormality diagnosis device 300 of this embodiment to set a threshold Vth for the RMS value, and to determine that the amount of grease remaining is insufficient, i.e., an abnormal condition, when the RMS value falls below the threshold Vth. 【0050】 In other words, the abnormality diagnosis device 300 of this embodiment is an abnormality diagnosis device 300 for a slewing device 400 comprising a hydraulic motor 2, a planetary gear reducer 10 coupled to the output shaft 4 of the hydraulic motor 2, and a pinion 17 provided on the output shaft 16 of the planetary gear reducer 10 that meshes with the internal teeth 18 of the slewing bearing 80 in the grease bath 40. The device 300 is equipped with a first vibration sensor 8 attached to the reducer housing 6, which is the housing of the planetary gear reducer 10, for detecting vibrations of the reducer housing 6, and a processor 9a that determines whether or not there is an abnormality in the slewing device 400 based on the detection result from the first vibration sensor 8. The processor 9a performs envelope processing on the first vibration data acquired by the first vibration sensor 8, converts the envelope-processed first vibration data into a spectral waveform, calculates the RMS value of the spectral waveform, and determines whether or not it is necessary to replenish the grease in the grease bath 40 (which can also be expressed as the amount of grease or the state of the grease) based on the RMS value. According to this embodiment, the timing for replenishing grease in the grease bath 40 can be determined based on the first vibration data from the first vibration sensor 8 attached to the reduction gear housing 6, allowing for grease to be replenished at the appropriate time, thereby suppressing damage to the slewing pinion 17. In particular, this configuration does not require a sensor to detect the amount of grease in the grease bath 40, making it easy to achieve low cost and maintenance-free operation. 【0051】 It should be noted that the calculation of the RMS value (step 224) after the envelope processing (step 222) adopted in this embodiment is not a common practice. Envelope processing is a process that extracts the contour lines of the waveform, and is therefore suitable for extracting shock excitations input at a specific period, but on the other hand, it makes it impossible to see the intensity of each shock excitation. In contrast, the RMS value is generally calculated for the purpose of evaluating the intensity of the waveform. In other words, calculating the RMS value of the waveform after envelope processing goes against the original purpose of calculating the RMS value, and therefore it is not generally done to calculate the RMS value after envelope processing. 【0052】 In the example in Figure 8, the threshold Vth is 1.5 [m / s²] 2The controller 9 is set to [ ] and when the acceleration RMS value falls below the threshold Vth at time T1, it determines that there is an abnormality (in other words, the grease in the grease bath 40 needs to be replenished), and displays a message 94 or graphic 95 on the monitor 91 prompting the operator to replenish the grease (grease up). This display informs the operator of the appropriate timing for greasing up, and the operator who sees the display can replenish the grease in the grease bath 40 to prevent damage to the pinion 17, and the hydraulic excavator can be put back into use without causing a long downtime. 【0053】 Note that the threshold RMS value shown in the diagram is Vth = 1.5 [m / s] 2 This is merely one example, and the threshold Vth may change depending on the safety factor setting trend, the variation in RMS values ​​due to the vibration measurement conditions of the first vibration sensor 8, the size of the hydraulic excavator, etc. 【0054】 By the way, in step 224, it is preferable to calculate the RMS value in the region of the spectral waveform below the frequency threshold Fth (low-frequency region). In other words, it is preferable to calculate the RMS value only in the low-frequency region. The reason for this is that noise has already been reduced by obtaining the waveform contour line in the envelope processing in step 222, and the components in the high-frequency region that exceed the frequency threshold Fth in the waveform after envelope processing have no physical meaning and only become noise (error), so the purpose is to exclude the inclusion of these high-frequency components in the RMS value. In other words, by calculating the RMS value limited to the low-frequency region, the inclusion of noise can be prevented, and the accuracy of determining the timing of grease replenishment can be improved. Note that the above example of a frequency threshold Fth that distinguishes the low-frequency region from the high-frequency region is 50 [Hz], but this value is just an example and can be adjusted as appropriate. Furthermore, RMS values ​​may be calculated in multiple frequency regions and compared with the threshold Vth. 【0055】 In the grease bath 40 illustrated in Figure 4, only one slewing pinion 17 is housed, and the upper slewing body 60 is rotated by only one set of slewing hydraulic motors 2 and planetary gear reducers 10. However, as the size of the hydraulic excavator increases, multiple slewing pinions 17 may be housed in the grease bath 40, and the upper slewing body 60 may be rotated by multiple sets of slewing hydraulic motors 2 and planetary gear reducers 10. This embodiment is also applicable in such cases. However, it is not necessary to input vibration data from all of the first vibration sensors 8 attached to the cover of each planetary gear reducer 10 to the controller 9; it is sufficient to input vibration data from any one of the multiple first vibration sensors 8 to the controller 9. This is because each slewing pinion 17 moves within the grease bath 40 under the same conditions, so the amount of grease can be determined from the data of one first vibration sensor. 【0056】 <Second Embodiment> In the above embodiment (first embodiment), the case in which the controller 9 is used to determine the amount of grease in the grease bath 40 (for example, whether or not replenishment is necessary) was described. However, by simply adding the second vibration sensor 7, the controller 9 can also perform abnormality diagnosis of the planetary gear reducer 10. This embodiment will describe the specific method. The abnormality diagnosis device of this embodiment comprises a first vibration sensor 8 attached to the reducer housing 6, a second vibration sensor 7 attached to the motor housing 1, and a controller 9. 【0057】 Figure 9 shows an example of a flowchart of the abnormality diagnosis process performed by the controller 9 of this embodiment. The controller 9 executes the process shown in Figure 9 based on the program stored in the memory device and the vibration data acquired via the first vibration sensor 8 and the second vibration sensor 7. As shown in Figure 9, the controller 9 can also execute the flow shown in Figure 5 (grease replenishment necessity determination flow) described in the first embodiment in parallel. However, the explanation of the flow shown in Figure 5 is omitted. 【0058】 In step 201, the controller 9 acquires second vibration data related to the hydraulic motor 2 via the second vibration sensor 7, and in step 202, it converts the second vibration data into a spectral waveform using a Fast Fourier Transform (FFT). Figure 10 shows an example of a spectral waveform obtained from the second vibration data related to the hydraulic motor 2. As shown in this figure, the spectral waveform is represented by frequency and amplitude. In addition, before performing the Fast Fourier Transform on the second vibration data in step 202, filtering to remove a certain frequency range in the second vibration data or envelope processing to convert the second vibration data into an envelope waveform may be performed. 【0059】 In step 203, the controller 9 calculates the peak frequency Fm corresponding to the peak period of vibration of the hydraulic motor 2 based on the spectral waveform acquired in step 202. One method for calculating the peak frequency Fm of the hydraulic motor 2 is to identify the frequency related to the peak with the largest amplitude in the spectral waveform acquired in step 202 as the peak frequency Fm. When the hydraulic motor 2 is rotating, a peak can be observed at a certain frequency Fm as shown in Figure 10, and this can be calculated as the peak frequency of the hydraulic motor 2. The calculated peak frequency Fm is stored in the memory device of the controller 9. 【0060】 In step 204, the controller 9 calculates the rotational speed of the hydraulic motor 2 based on the peak frequency of the hydraulic motor 2 calculated in step 203. The rotational speed of the hydraulic motor 2 can be calculated as the value obtained by dividing the peak frequency Fm by the number of pistons of the hydraulic motor 2. 【0061】 In step 205, the controller 9 calculates the characteristic frequencies fd of the multiple gears, i.e., the rotation period of each of the multiple gears, based on the rotational speed of the hydraulic motor 2 calculated in step 204 and the number of gears n and number of teeth T of the multiple gears constituting the planetary gear mechanism 3 located near the first vibration sensor 8. Here, since the first planetary gear mechanism 3A is located near the first vibration sensor 8, the characteristic frequencies fds, fdp, and fdr of the first sun gear 11a, the first planetary gear 12a, and the first internal gear 13a are calculated. 【0062】 When some teeth of a gear are damaged, vibration occurs at a certain frequency (characteristic frequency fd). Since the characteristic frequency fd depends on the rotational speed, the characteristic frequency of each gear is calculated from the rotational speed of the hydraulic motor 2 calculated in step 204. The characteristic frequencies fds, fdp, and fdr of each gear 11a, 12a, and 13a can be calculated using the following equations (1)-(3). Here, f is the rotational frequency, T is the number of teeth of each gear, n is the number of planetary gears, and the subscripts s, p, and r represent the sun gear, planetary gear, and internal gear, respectively. The rotational frequency fs of the first sun gear 11a can be calculated from the rotational speed of the hydraulic motor 2 calculated in step 204. 【0063】 【number】 【0064】 【number】 【0065】 【number】 【0066】 Alternatively, the meshing frequency fz may be calculated instead of the characteristic frequency fd. The meshing frequency fz indicates the number of times the gear teeth mesh per second, and in the case of the planetary gear reducer 10, it can be calculated using the following formula (4). 【0067】 【number】 【0068】 Furthermore, in step 206, the controller 9 acquires first vibration data related to the planetary gear reducer 10 via the first vibration sensor 8, and in step 207, it converts the first vibration data into a spectral waveform using a Fast Fourier Transform (FFT). Figure 11 shows an example of a spectral waveform obtained from the first vibration data related to the planetary gear reducer 10. Note that, as processing before performing the Fast Fourier Transform on the first vibration data in step 207, filtering to remove a certain frequency range in the first vibration data or envelope processing to convert the first vibration data into an envelope waveform may be performed. 【0069】 The spectral waveform in Figure 6 shows an example where the first sun gear 11a is damaged. A peak at the peak frequency Fm of the hydraulic motor 2 calculated in step 203, and two peaks occurring at the characteristic frequency fds and its integer multiple frequency 2fds due to the damage to the first sun gear 11a can be observed. Note that when there is no damage to any gear (i.e., under normal conditions), no peaks are observed at the characteristic frequency fd and its integer multiple frequency nfd. Furthermore, if the gear damage is severe and the resulting vibrations are large, a peak at the characteristic frequency may also be observed in the spectral waveform of the hydraulic motor 2. In this regard, since the vibrations due to the damage to the first sun gear 11a in this embodiment are minute, the peak at the characteristic frequency fds is hardly observed in the spectral waveform of the hydraulic motor 2 in Figure 10. 【0070】 In step 208, the controller 9 searches for a peak at the peak frequency Fm of the hydraulic motor 2 calculated in step 203 from the spectral waveform obtained by converting the first vibration data in step 207, and removes the peak if one is found. That is, in the example in Figure 11, the amplitude at the frequency Fm enclosed by the dashed line is set to zero to remove the peak. If the characteristic frequency fd and the peak frequency Fm of the hydraulic motor 2 are close together, the amplitude of the peak frequency Fm may be included in the characteristic frequency amplitude calculated (extracted) in the subsequent step 209, which may lead to a misdiagnosis. However, by removing the peak at the peak frequency Fm as in this embodiment, it is easy to determine whether or not a peak occurs at the characteristic frequency fd of each gear in the remaining spectral waveform, thereby reducing the influence of noise generated by the rotation of the hydraulic motor 2 and consequently improving the accuracy of abnormality diagnosis. Note that the frequency from which the peak is removed is not limited to the peak frequency Fm, but may also be a predetermined range of frequencies before and after the peak frequency Fm. Furthermore, Figure 12 shows an example of the spectral waveform of the vibration of the planetary gear reducer 10 under normal conditions with no damage to any of the gears (however, the peak frequency Fm of the hydraulic motor 2 has been removed). 【0071】 In step 209, the controller 9 extracts the amplitudes at each feature frequency fds, fdp, and fdr calculated in step 205 from the spectral waveform after peak removal in step 208. At this time, the amplitudes at frequencies that are integer multiples of each feature frequency fds, fdp, and fdr may be further extracted. When extracting the amplitudes, the controller 9 may consider the error in the calculated rotational speed of the hydraulic motor 2 and search for the largest peak in the range of ± several Hz of the frequency to be extracted, and use the amplitude of that largest peak as the amplitude at the frequency to be extracted. 【0072】 In step 210, the controller 9 compares the amplitudes of each feature frequency fds, fdp, and fdr extracted in step 209 with thresholds Ats, Atp, and Atr associated with each feature frequency. Based on the results of this comparison, the controller 9 diagnoses that there is no abnormality if the amplitude is less than or equal to the threshold At (step 212), and diagnoses that the gear associated with that feature frequency fd is damaged (abnormality detected) if the amplitude is greater than the threshold At (step 211). The threshold At is a pre-set value. The threshold At can be determined by methods such as experimentation, using the normal amplitude value or an integer multiple thereof, or by machine learning. The threshold At may differ for each feature frequency. 【0073】 In the example spectral waveform of the reducer 10 in Figure 11, peaks are found in the amplitude at the characteristic frequency fds and twice that frequency, 2fds, of the first sun gear 11a in step 209. In step 210, the amplitude of each found peak is compared with the threshold Ats, and since the amplitude of each found peak is greater than the threshold Ats, it is diagnosed that the first sun gear 11a is damaged (step 211). 【0074】 (effect) As described above, in this embodiment, the abnormality diagnosis device 300 for the planetary gear reducer 3 in a hydraulic excavator 100 driven by a hydraulic motor 2 and a planetary gear reducer 3 coupled to the output shaft 4 of the hydraulic motor 2 includes a first vibration sensor 8 attached to the reducer housing 6, which is the housing of the planetary gear reducer 3, and which detects vibrations of the reducer housing 6; a second vibration sensor 7 attached to the motor housing 1, which is the housing of the hydraulic motor 2, and which detects vibrations of the motor housing 1; and a processor (controller 9) that determines whether or not there are abnormalities in the multiple gears 11, 12, 13 included in the planetary gear reducer 3 based on the detection results from the first vibration sensor 8 and the second vibration sensor 7. The processor (controller 9) then calculates the peak frequency Fm corresponding to the peak period of vibration of the hydraulic motor 2 and the rotational speed of the hydraulic motor 2 from the second vibration data acquired by the second vibration sensor 7. Based on the rotational speed of the hydraulic motor 2, the number of gears 11, 12, and 13, and the number of teeth on each of the gears 11, 12, and 13, it calculates the characteristic frequency fd corresponding to the rotational period of each of the gears 11, 12, and 13. Based on the peak frequency Fm of the hydraulic motor 2 and the amplitude at the characteristic frequency of the first vibration data acquired by the first vibration sensor 8, it determines whether or not there is an abnormality in the gears 11, 12, and 13. 【0075】 In other words, in the abnormality diagnosis device 300 of this embodiment and the hydraulic excavator (construction machine) 100 including it, a second vibration sensor 7 is attached to the housing 1 of the hydraulic motor 2, and the peak frequency Fm of the hydraulic motor 2 is calculated by using the second vibration data acquired using this second vibration sensor 7, and the rotational speed of the hydraulic motor 2 is calculated from the calculated peak frequency Fm. That is, the rotational speed of the hydraulic motor 2 is calculated using the second vibration data without directly acquiring it with a rotational speed sensor or the like. Then, the characteristic frequency fd of each gear is calculated using the calculated rotational speed of the hydraulic motor 2, and by removing the amplitude at the peak frequency of the hydraulic motor 2 from the spectral waveform acquired using the first vibration sensor 8, abnormality diagnosis of the gears based on the characteristic frequency fd of the planetary gear reducer 10 connected to the hydraulic motor 2 is realized. In other words, the abnormality diagnosis device of this embodiment can calculate the rotational speed of the hydraulic motor 2 using the second vibration sensor 7 in a planetary gear reducer connected to a hydraulic motor of a construction machine where it is difficult to directly acquire rotational speed data, so abnormality diagnosis of planetary gear reducers for construction machines can be easily performed. 【0076】 In particular, the abnormality diagnosis device of this embodiment can be configured simply by adding a second vibration sensor 7 to the hardware configuration of the first embodiment and adding calculation processing performed by the controller 9. It exhibits a remarkable effect compared to conventional abnormality diagnosis devices in that it can diagnose abnormalities in the planetary gear reducer 10 and the slewing device pinion 17 with almost the same hardware configuration. 【0077】 In addition, although the above description concerns the case where the first vibration sensor 8 is attached near the first planetary gear mechanism 3A, it goes without saying that the first vibration sensor 8 can also be attached near the second planetary gear mechanism 3B to diagnose abnormalities in the gears included in the second planetary gear mechanism 3B. 【0078】 Furthermore, although the characteristic frequency fd of each gear is calculated in step 205 in Figure 9, etc., it is also possible to calculate only the characteristic frequency fd of a specific gear. In this case, in step 209, the amplitude of the characteristic frequency fd of that specific gear and the amplitude of frequencies that are integer multiples of that characteristic frequency fd are extracted, and in step 210, the presence or absence of an abnormality in that specific gear is determined by comparing the extracted amplitude with a threshold. 【0079】 Furthermore, although the above explanation used Figure 2, in which two vibration sensors 7 and 8 are attached to the housings 1 and 6 of the hydraulic motor 2 and planetary gear reducer 10, these two vibration sensors 7 and 8 do not need to be permanently attached to the housings 1 and 6. In other words, the two vibration sensors 7 and 8 can be attached to the housings 1 and 6 only during maintenance. 【0080】 The present invention is not limited to the embodiments described above, and includes various modifications that do not depart from the spirit of the invention. For example, the present invention is not limited to having all the configurations described in the embodiments described above, but also includes configurations in which some of those configurations are omitted. Furthermore, it is possible to add or replace some of the configurations of one embodiment with the configurations of another embodiment. 【0081】 In the above embodiment, a slewing device equipped with a hydraulic motor was illustrated, but an electric motor may be used instead of a hydraulic motor, or a hybrid motor combining a hydraulic motor and an electric motor may be used. 【0082】 Furthermore, each of the configurations related to the controller 9 described above, as well as the functions and execution processes of each of those configurations, may be partially or entirely implemented in hardware (for example, by designing the logic for executing each function using an integrated circuit). Alternatively, the configurations related to the controller 9 may be expressed as a program (software) that is read and executed by an arithmetic processing unit (e.g., a CPU) to realize each of the functions related to the controller 9's configuration. Information related to such a program can be stored, for example, in semiconductor memory (flash memory, SSD, etc.), magnetic storage devices (hard disk drives, etc.), and recording media (magnetic disks, optical disks, etc.). 【0083】 Furthermore, in the descriptions of each embodiment above, the control lines and information lines shown are those deemed necessary for the description of that embodiment, but this does not necessarily mean that all control lines and information lines related to the product are shown. In reality, it is safe to assume that almost all components are interconnected. [Explanation of symbols] 【0084】 1…Housing (motor housing), 2…Hydraulic motor (swivel hydraulic motor), 3…Planetary gear mechanism, 4…Output shaft, 5…Bearing, 6…Housing (reducer housing), 7…Second vibration sensor, 8…First vibration sensor, 9…Controller, 9a…Processor, 10…Planetary gear reducer, 11a…First sun gear, 11b…Second sun gear, 12a…First planetary gear, 12b…Second planetary gear, 13a…First internal gear ,13b…Second internal gear,14a…First planetary gear pin,14b…Second planetary gear pin,15a…First carrier,15b…Second carrier,16…Output shaft (rotating shaft),17…Pinion,18…Internal teeth,30…Front working device (working device),40…Grease bath,60…Upper slewing body,61…Slewing frame,80…Slewing bearing,81…Inner ring,82…Outer ring,100…Hydraulic excavator,300…Anomaly diagnosis device

Claims

[Claim 1] An abnormality diagnosis device for a slewing device comprising a motor, a planetary gear reducer coupled to the output shaft of the motor, and a pinion provided on the output shaft of the planetary gear reducer that meshes with the internal teeth of a slewing bearing in a grease bath, A first vibration sensor is attached to the reduction gear housing, which is the housing of the planetary gear reducer, and detects vibrations of the reduction gear housing. The system includes a processor that determines whether or not there is an abnormality in the slewing device based on the detection result from the first vibration sensor, The aforementioned processor, The first vibration data acquired by the first vibration sensor is subjected to envelope processing. The envelope-processed first vibration data is converted into a spectral waveform, The RMS value of the spectral waveform is calculated, When the RMS value is below a predetermined threshold, it is determined that the amount of grease in the grease bath has decreased to an amount that requires replenishment. A device for diagnosing abnormalities in a slewing mechanism, characterized by the above features. [Claim 2] In the abnormality diagnosis device for a slewing device according to claim 1, The aforementioned processor is characterized by calculating the RMS value in a region of the spectral waveform below a predetermined frequency, and is used as an abnormality diagnosis device for a turning device. [Claim 3] In the abnormality diagnosis device for a slewing device according to claim 1, The rotating device abnormality diagnosis device is characterized in that when the processor determines that it is necessary to replenish the grease in the grease bath, it displays that fact on the monitor. [Claim 4] In the abnormality diagnosis device for the slewing device according to claim 2, An abnormality diagnosis device for a turning device, characterized in that the predetermined frequency is 50 Hz. [Claim 5] In the abnormality diagnosis device for a slewing device according to claim 1, The first vibration sensor is an acceleration sensor, The aforementioned processor is characterized by calculating the acceleration RMS value as the RMS value, and is used as an abnormality diagnosis device for a turning device. [Claim 6] In the abnormality diagnosis device for a slewing device according to claim 1, A second vibration sensor is attached to the motor housing, which is the housing of the motor, and detects vibrations of the motor housing. The aforementioned processor, From the second vibration data acquired by the second vibration sensor, the peak frequency corresponding to the peak period of the motor's vibration and the rotational speed of the motor are calculated. Based on the rotational speed of the motor, the number of gears included in the planetary gear reducer, and the number of teeth on each of those gears, characteristic frequencies corresponding to the rotational periods of the gears are calculated. Based on the peak frequency of the motor and the amplitude at the characteristic frequency of the first vibration data acquired by the first vibration sensor, the presence or absence of abnormalities in the plurality of gears is determined. A device for diagnosing abnormalities in a slewing mechanism, characterized by the above features. [Claim 7] A motor that drives the rotating body, A planetary gear reducer connected to the output shaft of the motor, A pinion provided on the output shaft of the aforementioned planetary gear reducer, A slewing device comprising a slewing wheel having an inner ring that meshes with the pinion in a grease bath and is driven by the pinion, A rotating body driven by the aforementioned rotating device, A traveling body that supports the rotating body so that it can rotate via the aforementioned rotating device, A first vibration sensor is mounted on the reduction gear housing that covers the planetary gear reducer, A construction machine comprising a controller that determines whether or not there is an abnormality in the slewing device based on the detection result from the first vibration sensor, The aforementioned controller, The first vibration data acquired by the first vibration sensor is subjected to envelope processing. The envelope-processed first vibration data is converted into a spectral waveform, The RMS value of the spectral waveform is calculated, When the RMS value is below a predetermined threshold, it is determined that the amount of grease in the grease bath has decreased to an amount that requires replenishment. A construction machine characterized by the following features.

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