Electric winch and electric winch system

Abstract

The invention provides an electric hoist and an electric hoist system, in the electric hoist, regardless of the use mode on site, the deterioration degree of mechanical parts forming a hoisting device can be calculated with high precision. The electric winch updates the sampling period of the current flowing in the winch motor based on the stable working time and the motor driving frequency, and the current flowing in the winch motor is detected by a current detection part based on the updated sampling period.

Description

Technical Field

[0001] This invention relates to electric winches and electric winch systems. Background Technology

[0002] A hoist, as a type of electric winch, is an industrial machine that uses a winch device with an electric motor to raise a wire rope, thereby moving a suspended load on a crane hook mounted on the wire rope upwards or downwards.

[0003] The hoist has a rotational force transmission section between the hoisting motor and the hoisting device that actually raises and lowers the suspended load, which transmits the rotational force of the motor to the hoisting device. Specifically, the structure of the rotational force transmission section includes, for example, a splined shaft connected to the output shaft of the hoisting motor, which outputs rotational force at a constant speed. Then, a reduction gear is used to reduce the speed, transmitting a larger torque to the hoisting device.

[0004] Here, a splined shaft is a shaft used to transmit rotational force. One shaft (spline) has a shape formed by machining the teeth of a gear on its outer circumference. The other shaft (shroud) has a shape with grooves and protrusions machined to form a gear into which the spline is inserted. Rotational force can be transmitted by fitting the spline and the bushing together.

[0005] Because it uses gear engagement, it has the advantage of not producing slippage when a large rotational force is applied, compared to transmission mechanisms such as couplings. Therefore, it is often used for transmitting large rotational forces. Furthermore, a small gap exists to allow the spline to engage with the bushing axially. Thus, because it is axially movable, it can absorb any axial displacement between the spline side and the bushing side.

[0006] As mentioned above, when a hoist lifts a load, slippage occurs in the rotational force transmission section, posing a risk of tilting the load. Therefore, to prevent slippage, a splined shaft and a reduction gear are used in the part that transmits the rotational force of the motor to the hoisting mechanism. At this time, for example, there is a small gap between the spline and the bushing, so when the motor rotates, the gear located on the outer periphery of the spline contacts the concave-convex portion of the bushing.

[0007] In hoists, the motor rotates in different directions during the lifting and lowering of the load, causing contact between different sides of the gear teeth during forward and reverse rotation. Over long-term use, the splined gear teeth gradually wear and deteriorate, risking poor transmission of rotational force. Therefore, regular inspection of the splined shaft to confirm its condition is crucial.

[0008] The spline teeth engage with the bushing, so they cannot be directly inspected visually. Therefore, an open inspection is required by removing the spline from the bushing. As a method for inspecting the deterioration condition of the spline without removing it from the bushing, the method described in Patent Document 1 is known.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2023-115945 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] According to Patent Document 1, the device includes a current measuring unit that measures the current of an electric motor that rotates the spline shaft, a frequency component calculation unit that performs frequency analysis on the current measured by the current measuring unit and calculates a specific frequency component, and a wear condition estimation unit that estimates the wear condition of the gear of the spline shaft based on the specific frequency component calculated by the frequency component calculation unit.

[0014] Therefore, the wear and deterioration status of the gears on the spline shaft can be calculated based on the motor current. Thus, there is no need to check for spline opening, and because a current sensor is installed in the cable supplying power to the motor, it is not necessary to open the area near the spline shaft even if the sensor fails.

[0015] The aforementioned patent document 1 is a technique for estimating the wear of the spline shaft installed in electric winches such as hoists / cranes based on the current flowing in the motor of the winch. In order to perform this wear estimation with high accuracy, current data needs to be detected according to the required data specifications (such as the time width and sampling period of the data).

[0016] In this regard, the usage of winches such as hoists / cranes varies depending on the factory where they are installed, and the timing and speed for raising and lowering the load cannot be uniformly determined.

[0017] Therefore, when performing high-precision wear estimation of mechanical components such as splined shafts and reduction gears installed in hoists / cranes, it is necessary to understand the usage methods at the factory or other site where they are used, and update the current detection specifications of the hoist motors in a timely manner according to this method.

[0018] The purpose of this invention is to accurately calculate the degree of deterioration of the mechanical components constituting the winch device in electric winches, regardless of the usage method at the site.

[0019] Technical solutions for solving the problem

[0020] An electric winch according to one aspect of the present invention includes a winch motor, a power supply for supplying power to the winch motor, a winch device for raising and lowering a load, and a diagnostic device for detecting the deterioration of mechanical components constituting the winch device based on the current flowing in the winch motor. The electric winch is characterized in that the diagnostic device includes: a current detection unit for detecting the current flowing in the winch motor; a stability interval determination unit for determining a stable operating time during the raising and lowering of the load based on the current flowing in the winch motor; a drive frequency detection unit for detecting the drive frequency of the winch motor during the raising and lowering of the load based on the current flowing in the winch motor; and a sampling period determination unit for updating the sampling period of the current flowing in the winch motor based on the stable operating time and the motor drive frequency, wherein the current detection unit detects the current flowing in the winch motor based on the updated sampling period.

[0021] Invention Effects

[0022] According to one aspect of the present invention, it is possible to accurately calculate the degree of deterioration of the mechanical components of the winch device in an electric winch, regardless of the usage method at the site. Attached Figure Description

[0023] Figure 1 This is a schematic structural diagram of the electric winch in Example 1.

[0024] Figure 2 It is a diagram showing the shape and state of the cross-section of the spline shaft.

[0025] Figure 3 This is a diagram showing an example of the waveform of the current in a hoist motor.

[0026] Figure 4 This is a diagram illustrating an example of the frequency analysis results for a motor current.

[0027] Figure 5 This is a diagram showing the detailed structure of the stable interval determination part.

[0028] Figure 6A This is a schematic structural diagram of the electric winch in Example 2.

[0029] Figure 6B This is a schematic structural diagram of the electric winch in Example 3.

[0030] Figure 7 It is a rough diagram showing the relationship between wear and deterioration.

[0031] Figure 8It is a schematic diagram showing the changing relationship between wear and deterioration under varying working conditions during application.

[0032] Figure 9 This is a schematic structural diagram of the electric winch in Example 4.

[0033] Figure 10 This is a graph showing the frequency of occurrence of working time for lifting and lowering loads.

[0034] Figure 11 This is a schematic structural diagram of the electric winch system in Example 5. Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0036]

Example 1

[0037] exist Figure 1 The diagram shows a schematic structural diagram of the electric winch (e.g., hoist) of Embodiment 1.

[0038] The hoisting motor 1 is connected to a commercial or inverter-equivalent three-phase power supply 2. The hoisting motor 1 rotates forward and reverse by applying a three-phase voltage, and the hoisting device 3 controls the hoisted load (…). Figure 1 (Not shown in the diagram) The winding and lowering are performed.

[0039] In this structure, a splined shaft 4 that transmits rotational force from the hoisting motor 1 to the outside and a reduction gear 5 that reduces the speed of the hoisting motor 1 and amplifies the torque are provided between the hoisting motor 1 and the hoisting device 3. Furthermore, a current sensor 7 for measuring current is provided in at least one phase of the wire 6 that connects the hoisting motor 1 to the three-phase power supply 2. The current data measured by the current sensor 7 is input to the diagnostic device 10 to diagnose the condition of the splined shaft 4 and the reduction gear 5.

[0040] in addition, Figure 1 The example shown illustrates a current sensor 7 installed in the wire 6. If the three-phase power supply 2 is an inverter, information such as current feedback values ​​imported from the inverter can also be used. Furthermore, the diagnostic device 10 can be implemented in a component capable of computational processing, such as a microcomputer located inside the inverter.

[0041] The diagnostic device 10 includes a current detection unit 42 for detecting the current flowing in the hoist motor 1, a stability interval determination unit 43 for determining the stable operating time during lifting and lowering of the load based on the current flowing in the hoist motor 1, a drive frequency detection unit 44 for detecting the drive frequency of the hoist motor 1 during lifting and lowering of the load based on the current flowing in the hoist motor 1, and a sampling period determination unit 45 for updating the sampling period of the current flowing in the hoist motor 1 based on the stable operating time and the motor drive frequency. The current detection unit 42 detects the current flowing in the hoist motor 1 based on the updated sampling period.

[0042] Furthermore, the diagnostic device 10 includes a feature quantity calculation unit 40 that calculates a specified feature quantity based on the current flowing in the hoist motor 1, and a degradation degree calculation unit 41 that calculates the degradation degree based on the aforementioned feature quantity.

[0043] Here, in Figure 2 (a) shows a cross-section of the spline shaft.

[0044] Furthermore, the shape of the teeth is an example and is not limited to this. As shown in the figure, the spline 20 engages with the bushing 30 axially. A small gap G exists to allow for this engagement. Teeth 21 are provided at regular intervals in the circumferential direction in the spline 20.

[0045] Figure 2 (b) is a diagram showing the drive shaft, i.e., spline 20, rotating. When spline 20 rotates in the direction of arrow F, the tooth surface 21f of tooth 21 contacts the bushing, and the rotational force is transmitted from spline 20 to bushing 30. On the other hand, when spline 20 rotates in the opposite direction of arrow F, the tooth surface 21f contacts the bushing, and the rotational force in the opposite direction to arrow F is transmitted from bushing 30 to spline 20.

[0046] In the case of a hoist, for example, rotating in the direction of arrow F raises the load, and rotating in the opposite direction of arrow F lowers the load. Through repeated operations, the tooth surface 21f wears or is damaged, and the wear progresses. When the wear of the tooth surface 21f progresses, the tooth 21 deteriorates, resulting in poor transmission of rotational force. Therefore, it is necessary to detect the wear (degree of deterioration, hereinafter referred to as the degree of deterioration) of the tooth 21 before any abnormality occurs.

[0047] Next, an example of the method for calculating the degree of deterioration of the teeth of spline shaft 4 will be explained.

[0048] First of all, Figure 3 The diagram shows an example of the current waveform flowing in the winch motor 1 when a load is raised or lowered by an electric winch (e.g., a hoist).

[0049] like Figure 3As shown, during the initial transition phase of operation, the flow experiences an excessive current. Afterward, it transitions to a steady state, flowing with a constant current corresponding to the weight of the suspended load, and then stops. The current flowing in the T-section of the hoisting motor 1 during this operation is obtained using current sensor 7.

[0050] Regarding this, since the magnitude of specific frequency components is used when estimating the deterioration degree of the splined shaft 4 (described later), the current amplitude value of the hoisting motor 1 and the current data in the "stable operating range" with a constant drive frequency are used. Next, frequency analysis such as Fast Fourier Transform (FFT) is performed on the detected current in the T-range to calculate the spectrum.

[0051] Furthermore, the method for extracting steady-state current data in this frequency analysis can be described as follows: Figure 3 As shown, frequency analysis is performed using the entire data of interval T, but depending on the form of the computing device performing the analysis, it can also be divided into... Figure 3 For the small intervals Δt shown, frequency analysis is performed in each interval.

[0052] In particular, when the diagnostic device 10 is configured with a computing device such as a microprocessor, the amount of data processed is limited, so it is effective to perform calculations based on the data width of the small interval Δt as described above.

[0053] exist Figure 4 The image shows an example of the results after performing the frequency analysis described above.

[0054] like Figure 4 As shown, when performing frequency analysis on motor current, the current spectrum has a peak at the fundamental frequency of the current, and decreases from that point to the low-frequency and high-frequency sides.

[0055] The spectrum of a specific frequency in the spectrum is extracted as parameter P and stored. Additionally, in the example of diagnosing the splined shaft of a hoist, the value of the rotational frequency component appearing in the sideband as the fundamental wave frequency of the current is extracted as parameter P. Furthermore, the same frequency analysis is used in estimating the wear of reduction gears installed in the hoist, in addition to the splined shaft.

[0056] The frequency component (parameter P) used here is different from the parameter P used in the deterioration calculation of spline shaft 4 due to the reduction ratio. In this embodiment, the deterioration is diagnosed by focusing on the change in the distribution of parameter P caused by the rotational vibration due to the wear of the spline shaft. This change is defined as a characteristic quantity.

[0057] The part that calculates this characteristic quantity is the characteristic quantity calculation unit 40 provided within the diagnostic device 10. Furthermore, regarding the degree of deterioration of the spline shaft 4, the aforementioned characteristic quantity is determined based on the degree of change relative to the normal state. The part that calculates this degree of deterioration is the deterioration degree calculation unit 41 provided within the diagnostic device 10. Additionally, regarding the method for calculating this degree of deterioration, for example, a statistical quantity related to the distribution of parameter P is extracted as the characteristic quantity.

[0058] As a specific example of a statistic, in the frequency distribution of parameter P, in addition to the maximum and minimum values ​​and the average value, there are also the median, which represents the equal area on both sides of the distribution, and the mode, which is the most frequent value.

[0059] Alternatively, the range (difference between the maximum and minimum) or variance and standard deviation can be used as statistics representing the width of the distribution. Furthermore, skewness or kurtosis can be used as statistics representing the shape of the frequency distribution. In addition, the feature quantity is not limited to one; multiple statistics can be used, or new evaluation indicators calculated from multiple statistics can be used as feature quantities.

[0060] The above is a summary of the method for calculating the deterioration degree of the splined shaft 4 installed in an electric winch (e.g., a hoist). As explained earlier, current data of the winch motor 1 is obtained to calculate the deterioration degree, and frequency analysis is performed on this data.

[0061] Generally, to perform frequency analysis, data with a predetermined time span is required. However, the working time for the lifting and lowering of a hoist or crane's electric winch varies greatly depending on the location, environment, and type of load being lifted; even a rough estimate cannot be made consistently.

[0062] Therefore, when calculating the degree of deterioration of the splined shaft 4 and reduction gear 5 (mechanical components constituting the hoisting device) installed in an electric winch (e.g., a hoist), it is necessary to determine the time width and sampling time of the current data required to calculate the degree of deterioration whenever the equipment is installed in a factory or other facility.

[0063] To address this issue, in Embodiment 1 of the present invention, as follows: Figure 1 As shown, the diagnostic device 10 for the electric winch includes a unit that determines the current data required to calculate the degree of degradation and detects the current data accordingly. Specifically, this unit comprises a current detection unit 42, a stability range determination unit 43, a drive frequency detection unit 44, and a sampling period determination unit 45.

[0064] The operation of the electric winch in Example 1 will be described below.

[0065] First, as described above, frequency analysis is performed in the diagnostic device 10 using the current data of the hoisting motor 1. In this frequency analysis, in order to calculate the magnitude of the frequency band components corresponding to the diagnostic location (here assumed to be the spline shaft 4), the required frequency resolution Δf and current amplitude resolution ΔI for the diagnosis are predetermined.

[0066] Each discrimination ability is expressed by the following (Mathematical Formula 1) and (Mathematical Formula 2).

[0067] ·[Mathematical Formula 1]

[0068] Δf = fs / N (where fs is the sampling frequency and N is the number of data points)

[0069] ·[Mathematical Formula 2]

[0070] ΔI = A × f1 / fs (where A is the current amplitude and f1 is the motor driving frequency)

[0071] Here, the amount of data N is mostly determined in advance based on the computing speed and memory capacity of the diagnostic device 10, and the necessary range of the sampling period fs is determined according to the resolution required by each device.

[0072] On the other hand, the time width T of the current data is determined under the following (Mathematical Formula 3) conditions in a way that is within the "steady operating time" when the motor drive frequency and current amplitude are constant.

[0073] ·[Mathematical Formula 3]

[0074] T = x / f1 (where x is any integer)

[0075] Based on the above (Mathematical Formula 2) and (Mathematical Formula 3), it is known that the motor drive frequency during diagnosis needs to be known. Finally, the sampling period of the current data is determined using the following (Mathematical Formula 4). At this time, the sampling period fs is determined based on the necessary range of the above sampling period fs and the value of the integer x.

[0076] ·[Mathematical Expression 4]

[0077] fs = T / N

[0078] Through the above process, the stable operating time T and sampling period fs that provide sufficient accuracy for diagnosis can be determined for the frequency resolution Δf, current amplitude resolution ΔI, and other parameters. This determines the stable state range with the highest accuracy for calculating the degree of degradation.

[0079] Based on the above decision criteria, explain Figure 1 The operation of each module of the diagnostic device 10 shown.

[0080] First, in the current detection unit 42, the current data of the hoisting motor 1 is detected according to a preset sampling period (initial setting value). Then, based on the current data, in the stability interval determination unit 43, the time interval between the motor drive frequency and the constant current amplitude value (stable operating time [sec]) is measured.

[0081] At this time, the stable operating time (data time width) with the highest frequency of occurrence at the site of use of the equipment is extracted in the stable interval determination unit 43 during a specified period (e.g., 1 week to several weeks).

[0082] Here, for reference Figure 10 An example is given to illustrate the frequency of occurrence of the stable working time T (data time width) used for lifting and lowering loads.

[0083] The stable working time (data time width) for lifting and hoisting, i.e., the time for one stroke, varies depending on the settings of the electric winch (e.g., hoist).

[0084] For example, Figure 10 In (a), the stable working time (T1) occurs 10 times. Figure 10 In (b), the stable working time (T2) occurs 7 times. Figure 10 In (c), the stable working time (T3) occurs once.

[0085] Therefore, extract Figure 10 The stable operating time (T1) shown in (a) is the most frequent stable operating time (data time width) in the field of equipment use.

[0086] In addition, from the stable operating times T1 to Tn at the equipment's usage site, the stable operating time with the highest detection accuracy for judging the degree of degradation is extracted.

[0087] Here, in Figure 5 The detailed processing structure of the stable interval determination unit 43 is shown in the figure.

[0088] In the stable range determination unit 43, current data from the current detection unit 42 and drive frequency from the drive frequency detection unit 44 are input to the stroke data storage unit 50, and data for one stroke each of rising and falling are first stored.

[0089] Furthermore, based on the data from this one stroke and the current motor drive frequency, the stable operating time is measured in the stabilization time measurement unit 51. The conditions for the stable range at this time are set such that the amplitude of the current and the drive frequency are approximately constant. For example, the constant condition is that the changes in the amplitude and drive frequency converge within a preset value.

[0090] Next, the measured stable time value is stored in the stable time storage unit 52, and finally the stable time with the highest frequency of occurrence is output by the stable time determination unit 53 as the data time width.

[0091] Furthermore, regarding the frequency of occurrence mentioned here, since the calculated value represents the degree of deterioration (wear) of the teeth of spline shaft 4, a very high frequency of occurrence is not required. Additionally, the current data width is determined here based on the stable state time with the highest frequency of occurrence, in a manner that satisfies the aforementioned determination conditions. In this case, the stable operating time with the highest calculation accuracy of the deterioration degree among the extracted stable state times is specified. However, the determination of the current data width is not limited to the previous method; for example, the stable operating time with the highest frequency of occurrence can also be selected.

[0092] Thus, the stable operating range determination unit 43 determines the stable operating range based on the stable operating time with the highest frequency of occurrence during the operation of the electric winch and the driving frequency of the motor.

[0093] In addition, the stable range determination unit 43 extracts multiple stable working times during the operation of the electric winch, and determines the stable working range based on the stable working time with the highest detection accuracy of the degree of deterioration when judging the degree of deterioration and the motor drive frequency.

[0094] Furthermore, in the drive frequency detection unit 44, the motor drive frequency during the stable operating time is measured and extracted in parallel with the operation of the aforementioned stable range determination unit 43. Electric winches (e.g., hoists) can be either commercial power supply driven or inverter driven. If it is a commercial power supply driven type, only the commercial power supply frequency of the region needs to be considered. If it is an inverter driven type, the drive frequency can be changed at any time, so the function of the drive frequency detection unit 44 is required.

[0095] The sampling period determination unit 45 is input with the stable operating time obtained from the above processing and the current motor drive frequency, and the sampling period of the current data used in the degradation calculation is determined, and the sampling period in the current detection unit 42 is updated. Furthermore, the method for determining the sampling period at this time is as described above.

[0096] In addition, if the stable operating period or the motor drive frequency changes during the operation of the electric winch, the sampling period determination unit 45 updates the sampling period of the current based on the stable operating time with the highest frequency during the operation of the electric winch and the motor drive frequency after the change.

[0097] According to Example 1, in an electric winch, the degree of deterioration of the mechanical components constituting the winch device can be calculated with high accuracy regardless of the usage at the site. For example, the degree of deterioration of the splined shaft and reduction gear installed in winches such as hoists / cranes can be calculated with high accuracy regardless of the usage at the site.

[0098]

Example 2

[0099] Figure 6A This is a schematic structural diagram of the electric winch in Example 2.

[0100] Figure 6A The electric winch of Embodiment 2 shown is Figure 1 The difference between the electric winch of Embodiment 1 shown is that a degradation display unit 55 is provided inside the diagnostic device 10. Other structures are the same as... Figure 1 The electric winch shown in Example 1 is the same, so its description is omitted.

[0101] Next, the output method of the degradation degree of the diagnostic device 10 will be explained.

[0102] The way degradation is output is not particularly limited; for example, it can be exemplified as follows: Figure 6A As shown in Figure 1 As an example, a degradation degree display unit 55 is set up outside the structure to display the progression of the degradation degree.

[0103] Furthermore, as mentioned above, when calculating the degree of deterioration under the condition that the lifting and lowering time of the suspended load and the motor drive frequency remain unchanged in the operating state of the hoist at a certain site, such as... Figure 7 As shown in the sketch, the degree of degradation tends to increase in a manner roughly proportional to the amount of wear. Figure 7 The characteristics shown are presented as a linear relationship between wear and deterioration, but this example is only a schematic diagram and can be considered to be a distorted relationship due to differences in failure modes and / or shaft material, etc.

[0104] Next, in Figure 8 The diagram shows the degradation characteristics under various operating conditions, including variations in rise and fall times and changes in the motor drive frequency during operation.

[0105] like Figure 8 As shown in the diagram, when the rise and fall times or the motor drive frequency change, the degradation trend first deviates from the previous trend, and then the degradation trend before the change is restored by updating the changed stable operating time and the sampling time of the current data.

[0106] in addition, Figure 8The example shown automatically updates the sampling period of the current data and automatically continues degradation diagnosis after changing the rise or fall time or the motor drive frequency. However, it is also possible to not automatically update the sampling period of the current data. Figure 6A The degradation display unit 55 shows a message that the rise and fall time or the motor drive frequency has been changed, causing the degradation calculation to be temporarily stopped.

[0107]

Example 3

[0108] Figure 6B This is a schematic structural diagram of the electric winch in Example 3.

[0109] Figure 6B The electric winch of Embodiment 3 shown is Figure 6A The difference in the electric winch of Embodiment 2 shown is that a degradation display unit 55 is provided on the outside of the diagnostic device 10. Other structures are the same as... Figure 6A The electric winch shown in Embodiment 2 is the same, so its description is omitted.

[0110] like Figure 6B As shown, the diagnostic device 10 includes a transmitting unit 61. The diagnostic device 10 is wirelessly connected to a portable terminal 62 located outside the diagnostic device 10. The portable terminal 62 includes a receiving unit 63 and a degradation degree display unit 55. The degradation degree calculated by the degradation degree calculation unit 41 of the diagnostic device 10 is wirelessly received from the transmitting unit 61 by the receiving unit 63 of the portable terminal 62 and displayed on the degradation degree display unit 55.

[0111]

Example 4

[0112] Regarding the deterioration diagnosis of spline shaft 4, its function can also be achieved by pre-setting the stable operating time for rising and falling operations and the motor drive frequency in the diagnostic device 10. Figure 9 The structure of the diagnostic device 10 in this case is shown in the figure. Figure 9 This is a schematic structural diagram of the electric winch in Example 4.

[0113] Figure 9 The electric winch of Embodiment 4 shown is Figure 1 The difference between the electric winch of Embodiment 1 shown is that, Figure 9 China Replacement Figure 1 The stable range determination unit 43, the drive frequency detection unit 44, and the condition input unit 56 and the working condition setting unit 57 are respectively provided.

[0114] The stable working time for the lifting and lowering of the load and the motor drive frequency are input from the external condition input unit 56. Based on this input setting value, the working condition setting unit 57 determines the working conditions, determines the sampling period corresponding to this setting value, and updates the sampling period of the current detection unit 42. Other structures are similar to... Figure 1 The electric winch shown in Example 1 is the same, so the description is omitted.

[0115] The above is implemented in the working conditions setting section 57. Figure 5 The module's processing.

[0116] Specifically, in the working condition setting unit 57, current data from the current detection unit 42 and drive frequency from the condition input unit 56 are input to the stroke data storage unit 50, and data for one stroke each of rising and falling are first stored.

[0117] Furthermore, based on the data from this one stroke and the current motor drive frequency, the stable operating time is measured in the stabilization time measurement unit 51. The conditions for the stable range at this time are set such that the amplitude of the current and the drive frequency are approximately constant. For example, the constant condition is that the change in amplitude and drive frequency is within a preset value.

[0118] Next, the measured stable time value is stored in the stable time storage unit 52, and finally the stable time with the highest frequency of occurrence is output by the stable time determination unit 53 as the data time width.

[0119] Furthermore, regarding the frequency of occurrence mentioned here, since the calculated value represents the degree of deterioration (wear) of the spline shaft teeth, a very high frequency of occurrence is not required. Additionally, the current data width is determined here based on the stable state time with the highest frequency of occurrence, satisfying the aforementioned determination conditions. In this case, the stable operating time with the highest calculation accuracy of deterioration among the extracted stable state times is specified. However, the determination of the current data width is not limited to the previous method; for example, the stable operating time with the highest frequency of occurrence can also be selected.

[0120] In this way, the working condition setting unit 57 determines the stable working range based on the stable working time with the highest frequency of occurrence during the operation of the electric winch and the driving frequency of the motor.

[0121] In addition, the working condition setting unit 57 extracts multiple stable working times during the operation of the electric winch, and determines the stable working range based on the stable working time with the highest detection accuracy of the degree of deterioration when judging the degree of deterioration.

[0122]

Example 5

[0123] Figure 11This is a schematic structural diagram of the electric winch system of Embodiment 5. The electric winch system of Embodiment 5 is a structural example using a cloud.

[0124] Figure 11 The electric winch system of Embodiment 5 shown is... Figure 1 The difference in the electric winch of the illustrated embodiment 1 is that the electric winch is connected to the diagnostic device 110 via network 100.

[0125] Figure 11 In the electric hoisting system of Embodiment 5 shown, the diagnostic device 110 is configured on the cloud side via network 100.

[0126] Thus, in the electric winch system of Embodiment 5, the electric winch and the diagnostic device 110 are connected via a network 110, which serves as a communication line.

[0127] The electric winch has a winch motor 1, a three-phase power supply 2 for supplying power to the winch motor 1, a winch device 3 for raising and lowering the load, and a current detection unit 42 for detecting the current flowing in the winch motor 1.

[0128] The diagnostic device 110 detects the degree of deterioration of the mechanical components constituting the winch device based on the current flowing in the winch motor 1.

[0129] Specifically, the diagnostic device 110 includes a stability interval determination unit 43 that determines the stable working time during the lifting and lowering of the load based on the current flowing in the hoist motor 1, a drive frequency detection unit 44 that detects the drive frequency of the hoist motor 1 during the lifting and lowering of the load based on the current flowing in the hoist motor 1, and a sampling period determination unit 45 that updates the sampling period of the current based on the stable working time and the motor drive frequency.

[0130] The current detection unit 42 of the electric winch detects the current flowing in the winch motor 1 based on the updated sampling period determined by the sampling period determination unit 45 of the diagnostic device 110.

[0131] The stable operating range determination unit 43 determines the stable operating range based on the stable operating time with the highest frequency of occurrence during the operation of the electric winch and the driving frequency of the motor.

[0132] In addition, the aforementioned stable range determination unit extracts multiple stable operating times during the operation of the electric winch, and determines the stable operating range based on the stable operating time with the highest detection accuracy of the degradation degree when judging the degradation degree.

[0133] According to the above embodiments, in electric winches, the degree of deterioration of the mechanical components constituting the winch device can be calculated with high accuracy regardless of the usage at the site. For example, the degree of deterioration of the splined shaft and reduction gear installed in winches such as hoists / cranes can be calculated with high accuracy regardless of the usage at the site.

[0134] Here, the diagnostic device 10 described above is, for example, composed of a computer.

[0135] Computers use processors (such as CPUs and GPUs) to execute programs, and use storage resources (such as memory) and interface devices (such as communication ports) to perform the processing specified by the program.

[0136] Therefore, the entity performing the processing of the program can also be a processor. Similarly, the entity performing the processing of the program can also be a controller, device, system, computer, or node that has a processor. The entity performing the processing of the program only needs to be an arithmetic unit, but it can also include dedicated circuitry for specific processing. Here, dedicated circuitry can be, for example, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a CPLD (Complex Programmable Logic Device).

[0137] The program can be installed onto a computer from a program source. The program source can be, for example, a program distribution server or a storage medium readable by the computer. If the program source is a program distribution server, the program distribution server may include a processor and storage resources for storing the program to be distributed. The processor of the program distribution server then distributes the program to other computers. Furthermore, in this embodiment, two or more programs can be implemented as one program, or one program can be implemented as two or more programs.

[0138] For example, Figure 1 In the diagnostic device 10, the feature quantity calculation unit 40, the degradation degree calculation unit 41, the current detection unit 42, the stability interval determination unit 43, the drive frequency detection unit 44, and the sampling period determination unit 45 each perform their respective functions by executing programs by the processor.

[0139] Figure 9 In the diagnostic device 10, the condition input unit 56 and the working condition setting unit 57 perform their respective functions by executing programs by the processor.

[0140] Furthermore, in this embodiment, an electric winch was described with regard to a hoist, but it can also be applied to other electric winches, such as cranes, without any problems.

[0141] In addition, it can also be used in the same way as spline shafts for parts where degradation can be diagnosed based on the frequency analysis results of motor current (such as reduction gears).

[0142] Explanation of reference numerals in the attached figures

[0143] 1. Electric motor for hoisting

[0144] 2 Three-phase power supply

[0145] 3. Winching device

[0146] 4 splined shafts

[0147] 5. Reduction Gear

[0148] 6. Electrical wires

[0149] 7 Current Sensor

[0150] 10 Diagnostic Devices

[0151] 40 Feature Quantity Operation Unit

[0152] 41 Deterioration Calculation Department

[0153] 42 Current Detection Unit

[0154] 43. Stable Range Determination Department

[0155] 44 Drive Frequency Detection Unit

[0156] 45. Sampling Period Determination Department

[0157] 50. Trip Data Storage Department

[0158] 51. Stabilization Time Measurement Section

[0159] 52 Stable Time Preservation Section

[0160] 53. Stable Time Determination Department

[0161] 55 Degradation display section

[0162] 56. Conditional Input Section

[0163] 57. Working Conditions Setting Department

[0164] 61. Sending Department

[0165] 62 Portable Terminal

[0166] 63 Receiving Department.

Claims

1. An electric hoist comprising a hoist motor, a power source that supplies power to the hoist motor, a hoist device that raises and lowers a load, and a diagnosis device that detects a degree of deterioration of a mechanical component that constitutes the hoist device based on a current flowing in the hoist motor, the electric hoist characterized by: the diagnosis device comprising: a current detection section that detects the current flowing in the hoist motor; a stable interval determination section that determines a stable operation time when the load is raised and lowered based on the current flowing in the hoist motor; a drive frequency detection section that detects a drive frequency of the hoist motor when the load is raised and lowered based on the current flowing in the hoist motor; and a sampling period determination section that updates a sampling period of the current flowing in the hoist motor based on the stable operation time and the motor drive frequency, the current detection section detecting the current flowing in the hoist motor based on the updated sampling period.

2. The electric hoist according to claim 1, characterized in that: the stable interval determination section determines a stable operation interval based on the stable operation time and the motor drive frequency that have the highest frequency of occurrence in operation of the electric hoist.

3. The electric hoist according to claim 1, characterized in that: the stable interval determination section extracts a plurality of the stable operation times in operation of the electric hoist, and determines a stable operation interval based on the stable operation time and the motor drive frequency for which detection accuracy of the degree of deterioration becomes the highest when the degree of deterioration is judged.

4. The electric hoist according to claim 1, characterized in that: the sampling period determination section, in a case where the stable operation time or the motor drive frequency is changed in operation of the electric hoist, updates the sampling period of the current flowing in the hoist motor based on the stable operation time and the motor drive frequency that have the highest frequency of occurrence in operation of the electric hoist after the change.

5. The electric hoist according to claim 1, characterized in that: the diagnosis device, in a case where the stable operation time or the motor drive frequency is changed in operation of the electric hoist, notifies that the stable operation interval and the motor drive frequency have been changed.

6. The electric hoist according to claim 1, characterized in that: the diagnosis device comprises a characteristic quantity calculation section that calculates a prescribed characteristic quantity based on the current flowing in the hoist motor, and a degree of deterioration calculation section that calculates the degree of deterioration based on the characteristic quantity.

7. The electric hoist according to claim 1, characterized in that: a degree of deterioration display section that displays the degree of deterioration is provided inside or outside the diagnosis device.

8. An electric hoist comprising a hoist motor, a power source that supplies power to the hoist motor, a hoist device that raises and lowers a load, and a diagnosis device that detects a degree of deterioration of a mechanical component that constitutes the hoist device based on a current flowing in the hoist motor, the electric hoist characterized by: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The diagnostic device includes: a current detection section that detects current flowing in the hoist motor; a condition input section that sets in advance a stable operation time and a motor drive frequency at the time of lifting and lowering of the load; an operation condition setting section that sets an operation condition of the electric hoist based on the current flowing in the hoist motor and the stable operation time and the motor drive frequency; and a sampling period decision section that updates a sampling period of the current flowing in the hoist motor based on the operation condition of the electric hoist, the current detection section detects the current flowing in the hoist motor based on the updated sampling period.

9. The electric hoist according to claim 8, wherein: the operation condition setting section decides a stable operation section based on the stable operation time and the motor drive frequency in which the frequency of occurrence is highest in the operation of the electric hoist.

10. The electric hoist according to claim 8, wherein: the operation condition setting section extracts a plurality of the stable operation times in the operation of the electric hoist, and decides a stable operation section based on the stable operation time and the motor drive frequency in which the detection accuracy of the degree of deterioration becomes highest in judging the degree of deterioration.

11. The electric hoist according to claim 8, wherein: the diagnostic device includes a characteristic quantity calculation section that calculates a prescribed characteristic quantity based on the current flowing in the hoist motor, and a degree of deterioration calculation section that calculates the degree of deterioration based on the characteristic quantity.

12. The electric hoist according to claim 8, wherein: a degree of deterioration display section that displays the degree of deterioration is provided inside or outside the diagnostic device.

13. An electric hoist system in which an electric hoist and a diagnostic device are connected via a communication line, characterized in that: the electric hoist includes a hoist motor, a power source that supplies power to the hoist motor, a hoist device that lifts and lowers a load, and a current detection section that detects current flowing in the hoist motor, the diagnostic device detects a degree of deterioration of a mechanical component that constitutes the hoist device based on the current flowing in the hoist motor, the diagnostic device includes: a stable section decision section that decides a stable operation time at the time of lifting and lowering of the load based on the current flowing in the hoist motor; a drive frequency detection section that detects a drive frequency of the hoist motor at the time of lifting and lowering of the load based on the current flowing in the hoist motor; and a sampling period decision section that updates a sampling period of the current flowing in the hoist motor based on the stable operation time and the motor drive frequency, the current detection section of the electric hoist detects the current flowing in the hoist motor based on the sampling period updated by the sampling period decision section of the diagnostic device.

14. The electric hoist system according to claim 13, wherein: The stable section determination unit determines a stable operation section based on the stable operation time and the motor drive frequency at which the detection accuracy of the deterioration degree is highest.

15. The electric hoist system of claim 13, wherein: The stable section determination unit extracts a plurality of the stable operation times in the electric hoist operation, and determines a stable operation section based on the stable operation time and the motor drive frequency at which the detection accuracy of the deterioration degree is highest when judging the deterioration degree.

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