TECHNICAL FIELD
[0001] The present invention relates to a hoist life calculating device.
BACKGROUND ART
[0002] As a background art of the technical field, there is
JP 2010-180001 A (Patent Literature 1). In this publication, it is disclosed that "provided are a
crane operating situation managing device and a crane having the same, capable of
obtaining information necessary to precisely estimate a life of a crane according
to operation situations considering a loading rate, an operation cycle, and an operating
time thereof'.
CITATION LIST
PATENT LITERATURE
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0004] In PATENT LITERATURE 1, there is a description about the measurement of an operation
cycle of a hoist necessary to estimate a life of the hoist. However, in PATENT LITERATURE
1, "a configuration of counting both of the number of ground cutting times and the
number of lifting operation times" is disclosed, but the number of lowering operation
times is not counted. For this reason, it is difficult to estimate the life of the
hoist with high precision.
[0005] In addition, in PATENT LITERATURE 1, only the number of operation times and the operating
time for each load are measured, but a pausing time is not measure. For this reason,
it is difficult to accurately measure a ratio of the operating time and the pausing
time (that is, a use frequency) as one of measured values for comprehensively determining
the life of the hoist.
[0006] Considering the problems described above, an object of the invention is to provide
a hoist life calculating device capable of estimating a life of a hoist with high
precision.
SOLUTION TO PROBLEM
[0007] According to the present invention, there is provided a hoist life calculating device
according to claim 1.
[0008] The hoist life calculating device may optionally be as specified in claim 2.
ADVANTAGEOUS EFFECTS OF INVENTION
[0009] According to the invention, it is possible to provide a hoist life calculating device
capable of estimating a life of a hoist with high precision.
[0010] Problems, configurations, and effects other than the above description are clarified
by the following description of embodiments.
BRIEF DESCRIPTION OF DRAWINGS
[0011]
FIG. 1 is an example of a diagram illustrating a configuration of a hoist life calculating
device.
FIG. 2 is an example of a perspective view illustrating an overall configuration of
an inverter crane apparatus.
FIG. 3 is an example of a block diagram illustrating a configuration of a main part
of an inverter crane apparatus.
FIG. 4 is an example of a flowchart illustrating a process at a timing of start.
FIG. 5 is an example of a flowchart illustrating a process of a load determining unit.
FIG. 6 is an example of a flowchart illustrating a process of an operating time measuring
unit.
FIG. 7 is an example of a flowchart illustrating a process of an operation cycle measuring
unit.
FIG. 8 is an example of a flowchart illustrating a process of a loading time rate
measuring unit.
FIG. 9 is an example of a method of an operating time reserving process.
FIG. 10 is an example of displaying by a PC or the like.
FIG. 11 is an example of a configuration of a display relation of a hoist and transverse
inverter controlling unit.
FIG. 12 is an example of displaying by a hoist and transverse inverter controlling
unit.
FIG. 13 is an example of a load determination value according to output frequencies.
FIG. 14 is an example of a load determination value according to output frequencies.
DESCRIPTION OF EMBODIMENTS
[0012] Hereinafter, embodiments will be described with reference to the drawings.
[0013] FIG. 1 is an example of a diagram illustrating a configuration of a hoist life calculating
device. FIG. 2 is a perspective view illustrating an overall configuration of an inverter
crane apparatus provided with a hoist life calculating device according to this embodiment,
and FIG. 3 is a block diagram illustrating a configuration of a main part of an inverter
crane apparatus.
[0014] First, an outline of a hoist life calculating device and operations related to a
hoist will be described with reference to FIG. 1. A controlling unit of the hoist
operates a motor that is a driving unit by an operation instruction input from an
input device, and controls a brake close to the motor to be open, thereby driving
the hoist. Data of operation situations of the motor is transmitted to the controlling
unit, and the controlling unit performs a display control on a displaying unit to
display information of a list of operation situations corresponding to a content of
the operation. In addition, the list displayed by the displaying unit may be printed.
[0015] Next, an overall configuration of the inverter crane apparatus will be described
with reference to FIG. 2.
[0016] An inverter crane apparatus 100 includes a crane hook 1, a wire rope 2, a hoist induction
motor 3, a hoist 4, a transverse induction motor 5, a transverse device 6, a transverse
girder 7, a traveling induction motor 8, a traveling device 9, a traveling girder
10, a hoist and transverse inverter device (referred to as a main controlling unit)
11, a hoist and transverse inverter controlling unit 12 to be described later, an
operation input device 13, a hoist inverter 14 to be described later, a transverse
inverter 15 to be described later, an induction motor brake 16 to be described later,
a traveling inverter device 17, a traveling inverter controlling unit 18 to be described
later, and a traveling inverter 19 to be described later.
[0017] The inverter crane apparatus 100 moves a load suspended from the crane hook 1 in
a Z direction (indicated by arrows in a Z direction and a -Z direction), that is,
a vertical direction, by lifting and lowering the wire rope 2 by the hoist 4 provided
with the hoist induction motor 3. In addition, with respect to an X direction (indicated
by arrows in an X direction and a -X direction), the load is moved in the X direction
by the transverse girder 7 and the transverse device 6 provided with transverse induction
motor 5. In addition, with respect to a Y direction (indicated by arrows in a Y direction
and a -Y direction), the load is moved in the Y direction by the traveling girder
10 and the traveling device 9 provided with the traveling induction motor 8.
[0018] Next, a control configuration of the inverter crane apparatus will be described with
reference to FIG. 3.
[0019] The hoist induction motor 3 and the transverse induction motor 5 are controlled by
the hoist and transverse inverter controlling unit 12 illustrated in FIG. 3 provided
in the hoist and transverse inverter device 11. That is, when an operator inputs a
predetermined instruction from the operation input device 13, the hoist and transverse
inverter controlling unit 12 controls the hoist inverter 14 and the transverse inverter
15 to apply frequency, voltage, and current necessary for the control from the hoist
inverter 14 and the transverse inverter 15 to the hoist induction motor 3 and the
transverse induction motor 5 and to control the induction motor brake 16 to be open
at the same time, thereby moving the load suspended from the crane hook 1 in the Z
direction without falling down. The transverse device 6 moves the hoist 4 in the X
direction along the transverse girder 7.
[0020] Similarly, as for the traveling induction motor 8 suspended from the traveling device
9, when the operator inputs a predetermined instruction from the operation input device
13, the traveling inverter controlling unit 18 illustrated in FIG. 3 provided in the
traveling inverter device 17 controls the traveling inverter 19 to apply frequency,
voltage, and current necessary for the control from the traveling inverter 19 to the
traveling induction motor 8 and to control the induction motor brake 16 to be open
at the same time, thereby moving the hoist 4 in the Y direction along the traveling
girder 10.
[0021] In addition, the hoist inverter 14 includes a current measuring unit 20. The current
measuring unit 20 measures a current value for driving the hoist induction motor 3.
[0022] In addition, the hoist and transverse inverter controlling unit 12 includes a load
converting unit 21. The load converting unit 21 converts the current value data measured
by the current measuring unit 20 into load data by a predetermined calculation. That
is, since the current value for driving the hoist induction motor 3 is changed according
to a weight of the load suspended from the crane hook 1, it is possible to measure
the load by converting the current value into the load data by the load converting
unit 21. For example, as the load gets heavier, the current value for driving the
hoist induction motor 3 gets larger, and as the load gets lighter, the current value
for driving the hoist induction motor 3 gets smaller.
[0023] In addition, the hoist and transverse inverter controlling unit 12 includes a slippage
measuring unit 22. The slippage measuring unit 22 converts a signal from an encoder
23, which outputs a pulse signal corresponding to a rotation situation of the hoist
induction motor 3, into the number of rotations, and measures a slippage amount that
is a difference between the number of synchronous rotations calculated from an operation
frequency and the measured actual number of rotations. That is, since the slippage
amount is changed according to the weight of the load suspended from the crane hook
1, it is possible to measure the load by converting the slippage amount into the load
data by the load converting unit 21. For example, as the load gets heavier, the slippage
amount of the hoist induction motor 3 gets larger, and as the load gets lighter, the
slippage amount of the hoist induction motor 3 gets smaller.
[0024] The inverter control may be performed to operate in an operation frequency lower
than a rated speed, but in this case, the change amount of the current value changed
according to the weight of the load is small particularly in a lowering direction,
it is thus difficult to perform determination with high precision, but it is possible
to perform determination of the load with high precision in addition to the load determination
of the current value by having means for determining the load based on the slippage
amount.
[0025] The load detected as described above may be used in a process as it is, but the amount
of data is huge. In the embodiment, a rated load (100%) of the hoist is classified
into five patterns of no load (0%), a light load (1 to 25%), a medium load (26 to
50%), a heavy load (51 to 75%), and a superheavy load (76% or more), which are used
in a process.
[0026] In addition, it is obvious that a relation between a current value and load data
or a relation between a slippage amount and load data can be easily acquired experimentally
in advance or by a predetermined calculation.
[0027] A specific load determining method of the load converting unit 21 will be described
with reference to FIGS. 4 and 5. FIG. 4 is a flowchart illustrating a load determining
process at a timing of start, and FIG. 5 is a flowchart illustrating a load determining
process.
[0028] As for the start of the load determining process, for example, in a software interrupting
process for each 100 ms, when the induction motor brake 16 is open (S1), the load
determining process is started (S4).
[0029] In the load determining process, when the hoist is in an acceleration or deceleration
state, it is difficult to measure the current value and the slippage amount with high
precision, and thus it is necessary to measure the current value and the slippage
amount at a constant speed. As illustrated in FIG. 4, when there is an operation instruction
in an "upper" or "lower" direction (S101), as for the frequency output from the hoist
inverter 14 to the hoist induction motor 3, a target frequency instructed by the hoist
and transverse inverter controlling unit 12 is compared with an output frequency actually
output from the hoist inverter 14 (S102). When the instructed frequency is the same
as the output frequency or when the output frequency is higher than the instructed
frequency, it is in a constant speed state, and the current value and the slippage
amount are acquired (S103).
[0030] When the condition is not satisfied, the load determining process returns to the
initial state, and the process is ended (S109).
[0031] In addition, the detection is always performed on the current value and the slippage
amount regardless of the hoist state such as acceleration or deceleration.
[0032] The current values and the slippage amounts by the set number of acquisition times
are acquired (S104) and, when the acquiring of the current values and the slippage
amounts is completed, an average value is calculated (S105) after the acquired value
is reserved, for example, five times (S10) to suppress a variation among the acquired
values.
[0033] When each average value of the current values and the slippage amounts is calculated,
a total sum of the acquired values and the counted number of acquisition times are
cleared (S106). A value of the output frequency output from the hoist inverter 14
is compared with a reference value (for example, 30 Hz) of the set output frequency
(S107). In a case where the value is equal to or less than the reference value, the
slippage amount is used as a parameter of load determination, and a load class is
determined from the average slippage amount and the operation direction (S108). Meanwhile,
in a case where the value is larger than the reference value, the current value is
used as a parameter of load determination, and the load class is determined from the
average current value and the operation direction (112).
[0034] In addition, since the current value and the slippage amount are changed according
to the operation direction (Z direction) of the hoist, it is necessary to also determine
the operation direction from the parameter of the load determination, but it is possible
to know the operation direction when the input from the operation input device 13
to the hoist and transverse inverter controlling unit 12 is confirmed.
[0035] Herein, instead of using any one of the current value and the slippage amount as
the parameter of the load determination by the output frequency, both of them may
be used as the parameters of the load determination.
[0036] When the parameter for determining the load is prepared as described above, loads
are classified into five patterns according to classification determined in advance
as illustrated in FIGS. 13 and 14. For example, in a case where a current value of
11 A is detected in the operation in the upper direction at the output frequency 60
Hz, the load is determined as the medium load (S112).
[0037] Next, an operating time measuring process S5 illustrated in FIG. 4 will be described.
As illustrated in FIG. 3, the hoist and transverse inverter controlling unit 12 includes
an operating time measuring unit 24. The operating time measuring unit 24 measures
and integrates an opening control time of the induction motor brake 16 controlled
to be open by the hoist and transverse inverter controlling unit 12. That is, total
operating time is measured.
[0038] In addition, the operating time measuring unit 24 measures and integrates the opening
control time of the induction motor brake 16 for each load classification determined
by the load determining process. That is, the operating time for each load classification
is measured.
[0039] A specific operating time measuring method of the operating time measuring unit 24
will be described with reference to FIGS. 4 and 6. FIG. 6 is a flowchart illustrating
an operating time measuring process.
[0040] As for the start of the operating time measuring process, for example, in a software
interrupting process for each 100 ms, when the induction motor brake 16 is open (S1),
the load determining process (S4) is completed, and then the operating time measuring
process is started (S5).
[0041] When the operating time measuring process is performed, first, the total operating
time is counted up by 1 (S201). Then, the operating time for each load classification
is counted up by 1 from the determined load classification (S206 to S210). As described
above, it is possible to measure the total operating time and the operating time for
each load classification.
[0042] In addition, it is obvious that the conversion from the number of integrated times
of the operating time into an actual operating time is determined at the performing
interval of the operating time measuring process.
[0043] Next, an operation cycle measuring process S6 illustrated in FIG. 4 will be described.
As illustrated in FIG. 3, the hoist and transverse inverter controlling unit 12 includes
an operation cycle measuring unit 25. The operation cycle measuring unit 25 integrates
the number of times when the state of the induction motor brake 16 controlled to be
open by the hoist and transverse inverter controlling unit 12 is open and then returns
to the original state, for each determined load classification by the load determining
process. That is, the number of operation times for each load classification is measured.
[0044] A specific operation cycle measuring method of the operation cycle measuring unit
25 will be described with reference to FIGS. 4 and 7. FIG. 7 is a flowchart illustrating
an operation cycle measuring process.
[0045] As illustrated in FIG. 4, as for the start of the operation cycle measuring process,
for example, in a software interrupting process for each 100 ms, when the induction
motor brake 16 is open, a brake opening flag is set to 1 (S2), and when the induction
motor brake 16 is braked, the brake opening flag is set to 0 (S3). After the operation
of the brake opening flag is performed as described above, the operation cycle measuring
process is started (S6).
[0046] As illustrated in FIG. 7, when the operation cycle measuring process is performed,
first, the brake opening flag state is confirmed (S301), and the operation state of
the brake is also confirmed together (S302). When the brake opening flag is 1 and
the brake is in the braking state, the brake opening flag is set to 0 (S303).
[0047] When the brake opening flag is set to 0, the total number of operation times is counted
up by 1 (S304). Then, from the determined load classification, the number of operation
times for each load classification is counted up by 1 (S306 to S310). As described
above, it is possible to measure the total number of operation times and the number
of operation times for each load classification.
[0048] Next, a loading time rate measuring process S7 illustrated in FIG. 4 will be described.
First, calculation of a remaining lifetime will be described. As illustrated in FIG.
3, in order to calculate the remaining lifetime of the hoist, the hoist and transverse
inverter controlling unit 12 includes a remaining lifetime calculating unit 26. The
remaining lifetime calculating unit 26 calculates the remaining lifetime from the
operating time for each load classification.
[0049] A specific method of calculating the remaining lifetime of the hoist performed by
the remaining lifetime calculating unit 26 will be described. As for the remaining
lifetime of the hoist, first a loading rate is calculated on the basis of [MATH. 1].
K: loading rate
ti: operating time for each load classification
tT: total operating time
ti/tT: time rate for each load classification
P: loading ratio (table 1, values of LO to L4)
[0050] As the operating time for each load classification and the total operating time in
[MATH. 1] and the loading ratio, values illustrated in FIGS. 13 and 14 are used.
[0051] Then, the loading rate calculated by [MATH. 1] is divided by 0.63 that is a loading
rate in a case where the hoist is generally used, to calculate an equivalent loading
rate from (MATH. 2).

[0052] Then, an equivalent operating time is calculated from (MATH. 3). Herein, the value
measured as described above is used as the total operating time.

[0053] As described above, when the equivalent operating time and the equivalent loading
rate are determined, a remaining lifetime is calculated by (MATH. 4).

[0054] Since the set total operating time in (MATH. 4) can be determined from specifications
of the hoist, an initial value may be set in the remaining lifetime calculating unit
26. In addition, the set total operating time may be variable later.
[0055] Herein, the remaining lifetime is determined as described above, but a ratio of a
pausing time and an operating time of the hoist (that is, a loading time rate) is
necessary to comprehensively determine the remaining lifetime of the hoist. This is
because the hoist induction motor 3, the hoist inverter 14, and the like are loaded
in a case where the hoist is intensively operated for a short time.
[0056] In order to measure the loading time rate, the hoist and transverse inverter controlling
unit 12 includes a loading time rate measuring unit 27. The loading time rate measuring
unit 27 measures an opening control time of the induction motor brake 16 controlled
to be open by the hoist and transverse inverter controlling unit 12 so as to determine
the operating time and the pausing time, thereby calculating the loading time rate.
[0057] A specific method of measuring the loading time rate will be described with reference
to FIGS. 4 and 8. FIG. 8 is a flowchart illustrating a loading time rate measuring
process.
[0058] First, general calculation of the loading time rate will be described. The loading
time rate is represented using a unit %ED representing an operating time (minutes)
for 60 minutes. Since the operating time can be measured by confirming the operation
state of the induction motor brake 16, the pausing time can be measured similarly
by confirming the operation state of the induction motor brake 16.
[0059] As for the measuring of the loading time rate, as illustrated in FIG. 4, for example,
in a software interrupting process for each 100 ms, the loading time rate measuring
process is constantly performed without depending on the state of the induction motor
brake 16 (S7).
[0060] When the loading time rate measuring process is performed, first, the operation state
of the induction motor brake 16 is confirmed to determine whether operating or pausing
(S401). During operating, 100 ms is added to the integrated operating time (S402).
[0061] Then, it is confirmed whether or not the sum of the integrated operating time and
the integrated pausing time is 1 minute or more (S403). When it is less than 1 minute,
the interrupting process of the loading time rate measuring is ended. When it is 1
minute or more, an operating time reserving process (S404) is performed.
[0062] Herein, the operating time reserving process (S404) will be described with reference
to FIG. 9. In the operating time reserving process (S404), 60 reserving areas are
provided in a storing unit 28 of the hoist and transverse inverter controlling unit
12 in order to reserve, for example, 60 past operating times each having 1 minute
(that is, the operating time for past 60 minutes) ([1]). As the reserving areas, for
example, the area for reserving the newest operating time is an area 1, the area for
reserving the second newest operating time is an area 2, and sequentially, the area
for reserving the oldest operating time is an area 60.
[0063] Then, whenever the operating time reserving process (S404) is performed, the oldest
data is eliminated from the data reserved in the areas ([2]). In the determination
of the oldest data, at the time point of taking 60 areas in the storing unit, addresses
can be automatically assigned, for example, an address of the area 1 is 001, an address
of the area 2 is 002, ..., and an address of the area 60 is 060. Since the addresses
are sequential, it is possible to determine the oldest data by confirming the addresses.
[0064] Then, a process of moving the data of the area 59 to the area 60 and moving the data
of the area 58 to the area 59 is repeatedly performed until the data of the area 1
is moved to the data 2 ([3]).
[0065] Then, it is possible to reserve the operating time for past 60 minutes by reserving
the newest operating time is reserved in the area 1 ([4]).
[0066] When the operating time reserving process (S404) is ended, the integrated operating
time and the integrated pausing time are cleared (S405). By clearing them, it is possible
to measure the operating time for the next 1 minute.
[0067] Then, a loading time rate for 15 minutes is calculated (S406). In the calculating
method, the operating time for 15 minutes is summed from the newest data reserved
in the operating time reserving process (S404), the summed operating time is divided
by 15 minutes, and thus it is possible to calculate the loading time rate for 15 minutes.
Herein, as for the calculated loading time rate for 15 minutes, a higher rate may
be reserved as a maximum value in comparison with the previously calculated loading
time rate for 15 minutes.
[0068] Then, the loading time rate for 30 minutes (S407), the loading time rate for 45 minutes
(S408), and the loading time rate for 60 minutes (S409) are calculated, and the loading
time rate measuring process is ended. It is obvious that the method of the loading
time rate calculating process of each time interval is the same as the loading time
rate calculating process for 15 minutes, and the same is applied to each time. In
addition, it is obvious that modification is easily made, for example, each time interval
of the loading time rate calculating process is elongated or shortened.
[0069] As described above, when the measured or calculated data is eliminated at the time
of cutoff of a power source, the data is not possible to be accumulated, which is
meaningless. Accordingly, there is a need to reserve the data so as not to be eliminated
at the time of cutoff of the power source.
[0070] As a reserving method, the data is reserved in the storing unit 28 provided in the
hoist and transverse inverter controlling unit 12. In addition, the data may be reserved
in an external storing device such as a hard disk or a USB. As described above, as
a form of outputting the measured or calculated data, for example, when a diagram
illustrated in FIG. 10 is displayed by accessing a PC, the measured or calculated
data can be seen at a glance, and it is easy to comprehensively determine the remaining
lifetime of the hoist.
[0071] In addition, the measured or calculate data may be displayed by a digital display
provided in the controlling unit of the general inverter crane apparatus. In this
embodiment, a method of displaying the measured or calculated data by the digital
display will be described with reference to FIGS. 11 and 12.
[0072] In order to display the measured or calculated data, as illustrated in FIG. 11, the
hoist and transverse inverter controlling unit 12 includes a 7-segment LED display
29 that is a digital display capable of displaying characters, and four switches 30
for operating the display.
[0073] FIG. 12 illustrates an example of a display operating method and a display configuration
of the measured or calculated data displayed by the 7-segment LED display 29.
[0074] For example, in the operation to display the operating time, the number of operation
times is initially displayed, and a down-arrow switch is operated to select the operating
time. After selecting the operating time, the total operating time is displayed when
a right-arrow switch is operated. Then, when the down-arrow switch is operated, the
operating time of no load is displayed. When the down-arrow switch or up-arrow switch
is operated, the total operating time and the operating time for each load classification
can be displayed.
[0075] According to this embodiment, it is possible to display the remaining lifetime of
the hoist, and it is possible to provide the hoist life calculating device capable
of measuring and displaying the loading time rate, that is, use frequency of the hoist
with high precision, by measuring the operation situations also including the pausing
time.
[0076] In addition, since it is possible to measuring and displaying the total number of
operation times, the number of operation times for each load, the total operating
time, and the operating time for each load, it is possible to also provide determination
data in estimating the life of the hoist.
REFERENCE SIGNS LIST
[0077]
- 1:
- crane hook
- 2:
- wire rope
- 3:
- hoist induction motor
- 4:
- hoist
- 5:
- transverse induction motor
- 6:
- transverse device
- 7:
- transverse girder
- 8:
- traveling induction motor
- 9:
- traveling device
- 10:
- traveling girder
- 11:
- hoist and transverse inverter device
- 12:
- hoist and transverse inverter controlling unit
- 13:
- operation input device
- 14:
- hoist inverter
- 15:
- transverse inverter
- 16:
- induction motor brake
- 17:
- traveling inverter device
- 18:
- traveling inverter controlling unit
- 19:
- traveling inverter
- 20:
- current measuring unit
- 21:
- load converting unit
- 22:
- slippage measuring unit
- 23:
- encoder
- 24:
- operating time measuring unit
- 25:
- operation cycle measuring unit
- 26:
- remaining lifetime calculating unit
- 27:
- loading time rate measuring unit
- 28:
- storing unit
- 29:
- 7-segment led
- 30:
- operation switch