JP6435162B2 - Crane wire rope fatigue measurement method and apparatus - Google Patents

Description

  The present invention relates to a crane wire rope fatigue measurement method and apparatus.

  In general, a wire rope used in a crane or the like is repeatedly subjected to a load when a heavy object is lifted and lowered, and is subjected to bending stress when passing through a sheave and fatigues.

  For this reason, conventionally, an operator has regularly observed the wire rope to confirm whether or not the wire rope is broken. Alternatively, the life limit of the wire rope has been managed by setting a use limit in anticipation of a sufficient safety factor corresponding to the tension acting on the wire rope and the amount used, and setting the replacement time in advance.

  For example, Patent Document 1 shows a general technical level related to the life management of the wire rope.

JP 2004-251880 A

  However, in particular, in the case of a deck crane deployed on a cargo ship such as a container ship or a bulk carrier, the length of the wire rope reaches about 250 m and the above-mentioned scaffold is not secured at a high place. As described above, confirming whether or not the wire rope is broken is a difficult inspection work that is very burdensome for the worker, and takes time and labor.

  In the case of the deck crane, the load varies depending on the route of the cargo ship, for example, iron ore or grain, and the weight of the suspended load is often extremely different. As described above, it has been very difficult to determine the use limit of the wire rope and set the replacement time in advance. In such a situation, if the wire rope replacement time is uniformly set, the wire rope is broken because the soundness of the wire rope is not directly confirmed visually. Nevertheless, there has been a problem that the wire rope is continuously used, or even if the wire rope is in a healthy state, it is unconditionally disposed of at the time of replacement.

  The present invention has been made in view of the above-described conventional problems, and it is possible to quantitatively grasp the degree of fatigue of each part of the wire rope, shorten the inspection work time, and optimize the replacement time. An object of the present invention is to provide a rope fatigue level measuring method and apparatus.

但し、Ｔ：ワイヤロープの区切部位毎の疲労度［％］
Ｎ _ｉ ：第ｉ吊荷重領域Ｆ _ｉ での実際の曲げ回数
ｎ：自然数
α _ｉ ：疲労試験結果に基づく第ｉ吊荷重領域Ｆ _ｉ での曲げ回数換算係数
Ｎ _ＬＩＭ ：疲労試験結果に基づく疲労曲げ限度回数
から求めることを特徴とするクレーンのワイヤロープ疲労度計測方法にかかるものである。 The present invention is a wire rope fatigue measurement method for a crane that lifts and lowers a suspended load with a wire rope that is unwound from a drum and wound around a sheave,
By setting a virtual delimiter part by delimiting the wire rope at regular intervals in the length direction,
Measure the suspended load acting on the wire rope,
In a state where the wire rope receives the suspension load, the number of times that each section is bent through the sheave is integrated,
Based on the suspension load and the number of bending times, determine the degree of fatigue for each section of the wire rope ,
At this time, first suspension load region F ₁ , second suspension load region F ₂ ,... Nth suspension load region F _n are set in advance, and it is determined to which region the suspension load to be measured applies. The degree of fatigue for each section of the wire rope is expressed as follows:

However, T: Fatigue degree [%] for each section of the wire rope
N _i : Actual number of bendings in the i-th suspension load region F _i
n: natural number
α _i : Bending frequency conversion factor in _i- th suspension load region F _i based on fatigue test results
N _LIM : Fatigue bending limit based on fatigue test results
The present invention relates to a method for measuring the fatigue level of a wire rope of a crane.

  In the method of measuring the wire rope fatigue level of the crane, it is preferable that the suspension load is obtained from a hydraulic pressure of a hydraulic drive device that drives the drum.

  In the method of measuring a wire rope fatigue level of the crane, the suspension load may be obtained from a tension of the wire rope.

  In the method of measuring the wire rope fatigue level of the crane, it is preferable that the number of bendings is obtained from the number of rotations of the drum.

但し、Ｔ：ワイヤロープの区切部位毎の疲労度［％］
Ｎ _ｉ ：第ｉ吊荷重領域Ｆ _ｉ での実際の曲げ回数
ｎ：自然数
α _ｉ ：疲労試験結果に基づく第ｉ吊荷重領域Ｆ _ｉ での曲げ回数換算係数
Ｎ _ＬＩＭ ：疲労試験結果に基づく疲労曲げ限度回数
から求めることを特徴とするクレーンのワイヤロープ疲労度計測装置にかかるものである。 On the other hand, the present invention is a wire rope fatigue measuring device for a crane that lifts and lowers a suspended load by a wire rope that is unwound from a drum and wound around a sheave,
A suspension load measuring device for measuring a suspension load acting on the wire rope;
By setting a virtual delimiter by dividing the wire rope at regular intervals in the length direction, the suspension load measured by the suspension load measuring instrument is input, and the suspension load is received by the wire rope, A controller for accumulating the number of times each segmented portion is bent through the sheave, and determining a fatigue level for each segmented portion of the wire rope based on the suspension load and the number of bending steps ,
The controller stores a first suspension load region F ₁ , a second suspension load region F ₂ ,... Nth suspension load region F _n set in advance , and the suspension load to be measured is applied to which region. And determine the degree of fatigue for each section of the wire rope according to the following formula:

However, T: Fatigue degree [%] for each section of the wire rope
N _i : Actual number of bendings in the i-th suspension load region F _i
n: natural number
α _i : Bending frequency conversion factor in _i- th suspension load region F _i based on fatigue test results
N _LIM : Fatigue bending limit based on fatigue test results
The present invention relates to a wire rope fatigue level measuring device for a crane characterized in that it is obtained from the above.

  In the wire rope fatigue level measuring apparatus of the crane, the suspension load measuring device is a pressure gauge that measures the hydraulic pressure of a hydraulic drive device that drives the drum, and the suspension load is based on the hydraulic pressure measured by the pressure gauge. It is preferable to be configured to obtain

  In the wire rope fatigue measurement apparatus for the crane, the suspension load measuring device is a load meter that measures the tension of the wire rope, and is configured to obtain the suspension load based on the tension measured by the load meter. You can also.

  In the wire rope fatigue measurement device of the crane, it is preferable to include a drum rotation number detector for detecting the rotation number of the drum.

  The wire rope fatigue measurement device of the crane preferably includes a display for displaying the fatigue level of each section of the wire rope determined by the controller.

  According to the wire rope fatigue measurement method and apparatus of the crane of the present invention, it is possible to quantitatively grasp the fatigue degree of each part of the wire rope, and it is possible to shorten the inspection work time and optimize the replacement time. Can have an effect.

It is a figure which shows the Example of the wire rope fatigue degree measuring method and apparatus of the crane of this invention, Comprising: (a) is a side view of a deck crane, (b) represents typically the wire rope hung around a sheave. It is a perspective view. It is a perspective view which shows the division | segmentation site | part of the wire rope in the Example of the wire rope fatigue degree measuring method and apparatus of the crane of this invention. It is a control block diagram in the Example of the wire rope fatigue degree measuring method and apparatus of the crane of this invention, (a) is a figure at the time of using a pressure gauge as a hanging load measuring device, (b) is a hanging load measuring device. It is a figure at the time of using a load meter.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 3 show an embodiment of a wire rope fatigue measurement method and apparatus for a crane according to the present invention, and show an example applied to a deck crane 1 installed in a cargo ship SP as a crane.

  As shown in FIG. 1 (a), the deck crane 1 includes a support base 2 installed on a deck D of a cargo ship SP, a swivel mast 3 disposed on the support base 2 so as to be pivotable, and the swivel mast. And a jib 6 attached to a lower portion of the swivel mast 3 via a fulcrum pin 5 so as to be freely raised and lowered.

  A winding drum 7 is arranged inside the turning mast 3 of the deck crane 1, and a wire rope 8 fed out from the winding drum 7 has sheaves S1, S2, S3, as shown in FIG. It is hung around S4, S5, S6, S7, and S8 and is rooted at the upper end of the swivel mast 3 or the tip of the jib 6. The sheaves S1, S5, S7 are provided at the upper end of the swivel mast 3, the sheaves S2, S4, S6, S8 are provided at the tip of the jib 6, and the sheave S3 carries the suspended load C. A cargo block 10 to which a hanging hook 9 is attached is provided. When the wire rope 8 is wound up by the winding drum 7, the cargo block 10 is raised, and when the wire rope 8 is fed out by the winding drum 7, the cargo block 10 is lowered.

  A lifting drum 11 is arranged inside the turning mast 3 of the deck crane 1, and a wire rope 12 fed from the lifting drum 11 is attached to a sheave S 9 provided at the upper end of the turning mast 3. It is hung and is rooted at the upper end of the swivel mast 3 or the tip of the jib 6. When the wire rope 12 is wound up by the hoisting drum 11, the jib 6 is driven in a standing direction, and when the wire rope 12 is fed out by the hoisting drum 11, the jib 6 is driven in a lying down direction. It has become. In addition, instead of winding and unwinding the wire rope 12 by the lifting / lowering drum 11, the lifting / lowering of the jib 6 may be performed directly by the lifting / lowering hydraulic cylinder.

  In the case of the present embodiment, as shown in FIG. 2, a virtual delimiter B is set by dividing the wire rope 8 in the length direction at regular intervals (for example, about 1 [m] to 2 [m]). The suspension load f acting on the wire rope 8 is measured, and in the state where the suspension load f is received by the wire rope 8, the number of times that each section B is bent through the sheaves S1 to S8 is integrated, The fatigue level T for each section B of the wire rope 8 is obtained based on the suspension load f and the number of bendings.

  In measuring the number of times of bending, it is preferable that a drum rotation number detector 7b for detecting the rotation number of the winding drum 7 is provided as shown in FIGS. However, in this example, the drum rotation number detector 7b is directly connected to the winding drum 7. However, the present invention is not limited to this as long as the rotation number of the winding drum 7 can be detected.

  The suspension load f acting on the wire rope 8 is measured by the suspension load measuring device 13 and input to the controller 14 as shown in FIG. In the controller 14, the current position of each section B is obtained from the unwinding amount of the wire rope 8 based on the rotation speed of the winding drum 7 and the elevation angle of the jib 6. Thereby, in the controller 14, in the state where the suspension load f is received by the wire rope 8, the number of bendings in which each of the dividing portions B is bent through the sheaves S1 to S8 is integrated, and the suspension load f and Based on the number of times of bending, the fatigue level T for each section B of the wire rope 8 is obtained, and the fatigue level T is displayed on the display 15.

但し、Ｔ：ワイヤロープの区切部位毎の疲労度［％］
Ｎ_ｉ：第ｉ吊荷重領域Ｆ_ｉでの実際の曲げ回数
ｎ：自然数
α_ｉ：疲労試験結果に基づく第ｉ吊荷重領域Ｆ_ｉでの曲げ回数換算係数
Ｎ_ＬＩＭ：疲労試験結果に基づく疲労曲げ限度回数
から求めるようになっている。 More specifically, the first suspension load region F ₁ , the second suspension load region F ₂ ,..., The nth suspension load region F _n set in advance are stored in the controller 14. The controller 14 determines to which region the suspended load f to be measured is applied, and determines the fatigue level T for each section B of the wire rope 8 according to the following formula.

However, T: Fatigue degree [%] for each section of the wire rope
N _i : Actual bending number in the _i- th suspension load region F _i n: Natural number α _i : Bending number conversion factor in the _i- th suspension load region F _i based on the fatigue test result N _LIM : Fatigue bending based on the fatigue test result It comes to ask for from the limit number of times.

First, as a first test, the bending number conversion coefficient α _i is set as a first test by applying a suspension load in a certain reference suspension load region F _i to a wire rope and conducting a fatigue test in advance. The obtained fatigue bending limit is defined as the fatigue bending limit number N _LIM, and the bending number conversion coefficient at this time is defined as a reference bending number conversion coefficient. Here, the fatigue bend limit number N _LIM may be the number of bends at the time when the number of wire breaks of the wire rope reaches a value determined by a standard / standard (for example, JIS standard). The as second test, for example, when a pre-fatigue testing said first hanging load of large suspended load region F _i than test toward the wire rope, the fatigue bending limit is lower than the results of the first test Therefore, the bending number conversion coefficient α _i in this case is set to a value larger than the reference bending number conversion coefficient. In other words, this means that the number of times of bending when the load applied to the wire rope is larger than the reference suspension load is set to have a greater influence on the fatigue level. On the other hand, as the third test, for example, when a pre-fatigue testing said first hanging load of small suspended load region F _i than test toward the wire rope, the fatigue bending limit the results of the first test Therefore, the bending number conversion coefficient α _i in this case is set to a value smaller than the reference bending number conversion coefficient. In other words, this means that the number of bendings when the load applied to the wire rope is smaller than the reference suspension load is set to have a small influence on the fatigue level. Thus, by changing the setting of the suspension load region F _i and performing the wire rope fatigue test a plurality of times, the bending frequency conversion coefficient α _i for each suspension load region F _i can be set.

The following [Table 1] shows an example in which the first suspension load region F ₁ to the sixth suspension load region F ₆ are set with n = 6.

Hanging load f envisioned, for example, 0 to 30 when in the range of [ton], the load area F _{1 ~} sixth hanging load area F ₆ is divided into appropriate width load hanging the first of this range Based on the fatigue test results that are allocated and actually performed, the bending number conversion coefficients α _{1 to} α ₆ corresponding to the respective regions are set.

  On the other hand, the hydraulic pressure of the winding hydraulic drive device 7a (see FIG. 1A) for driving the winding drum 7 is higher as the suspension load f is larger and lower as the suspension load f is smaller. As shown in FIG. 3A, the vessel 13 is a pressure gauge 13a that measures the hydraulic pressure of the winding hydraulic drive device 7a, and can determine the suspension load f based on the hydraulic pressure measured by the pressure gauge 13a. .

  Further, since the tension of the wire rope 8 is proportional to the suspension load f, the suspension load measuring instrument 13 is a load cell 13b such as a load cell for measuring the tension of the wire rope 8, as shown in FIG. The suspension load f can also be obtained based on the tension measured by the load meter 13b.

  The fatigue level T of the section B of the wire rope 8 that is wound around the sheaves S5 to S8 among the sheaves S1 to S8 does not increase so much, so the section B of the section of the wire rope 8 that passes through the sheaves S1 to S4. It is also possible to obtain the fatigue level T by intensively integrating the number of bendings.

  Next, the operation of the above embodiment will be described.

  During operation of the deck crane 1, the suspension load f acting on the wire rope 8 is measured by the suspension load measuring device 13 and input to the controller 14. When the suspension load measuring device 13 is a pressure gauge 13a for measuring the hydraulic pressure of the winding hydraulic drive device 7a as shown in FIG. 3A, the suspension load is measured based on the hydraulic pressure measured by the pressure gauge 13a. f is determined. Further, when the suspension load measuring device 13 is a load meter 13b such as a load cell for measuring the tension of the wire rope 8, as shown in FIG. 3B, based on the tension measured by the load meter 13b. A suspension load f is obtained.

  In the state where the wire rope 8 receives the suspension load f, the current position of each virtual section B set by partitioning the wire rope 8 at regular intervals in the length direction is It is obtained from the unwinding amount of the wire rope 8 based on the rotation speed of the drum 7 and the elevation angle of the jib 6. As a result, the number of bendings at which each of the segmented portions B is bent through the sheaves S1 to S8 is integrated.

Here, as shown in [Table 1], when the first suspension load region F ₁ to the sixth suspension load region F ₆ are set with n = 6, the suspension load f measured by the controller 14 is It is determined which one of the first suspension load region F ₁ to the sixth suspension load region F ₆ is applied, and each time the segmented portion B is bent through one of the sheaves S1 to S8, it corresponds. “1” is added to any _{one of the} bending times N _{1 to} N ₆ .

Then, the fatigue level T for each section B of the wire rope 8 is periodically calculated from the above equation: T = (N ₁ × α ₁ + N ₂ × α ₂ + N ₃ × α ₃ +... + N ₆ × α ₆ ) / N _LIM × 100
As required.

  When T = 100 [%], it means that the fatigue level T of the section B of the wire rope 8 has reached its limit, and the fatigue level T is, for example, about 70 to 80 [%]. What is necessary is just to check the division | segmentation site | part B corresponding at the time.

  As a result, only the section B of the wire rope 8 in which the fatigue level T has increased needs to be intensively visually confirmed. Thus, like the deck crane 1, the length of the wire rope 8 reaches about 250 m. In addition, in the case where the inspection work in a situation where the scaffolding is not secured at a high place is forced, the burden on the worker in the inspection work for confirming whether the wire rope 8 is broken or not is greatly reduced, Inspection work time can be shortened.

  In the case of the deck crane 1, the load varies depending on the route of the cargo ship SP, for example, iron ore or grain, and the weight of the suspended load C is extremely different. There are many cases, but instead of setting the use limit of the wire rope 8 uniformly and setting the replacement time in advance as in the past, the section B of the wire rope 8 with the increased fatigue degree T is focused on. Since it can be visually confirmed, it can be avoided that the wire rope 8 is continuously used even though the strands of the wire rope 8 are broken, or the wire rope 8 in a healthy state is discarded.

  Thus, the fatigue level T for each part of the wire rope 8 can be quantitatively grasped, and the inspection work time can be shortened and the replacement time can be optimized.

The controller 14 stores a first suspension load region F ₁ , a second suspension load region F ₂ ,... Nth suspension load region F _n set in advance, and the suspension load f to be measured is applied to which region. Therefore, the fatigue level T for each section B of the wire rope 8 is obtained from the above-described formula, so that the fatigue level T can be calculated more clearly.

  The suspension load measuring device 13 is a pressure gauge 13a that measures the hydraulic pressure of a winding hydraulic drive device 7a that drives the winding drum 7, and the suspension load f is measured based on the hydraulic pressure measured by the pressure gauge 13a. Since it comprises so that it can obtain | require, the suspension load f can be calculated | required accurately using the pressure gauge 13a with which the hydraulic drive device 7a for winding is provided, without providing a special instrument.

  The suspension load measuring device 13 is a load meter 13b for measuring the tension of the wire rope 8, and is configured to obtain the suspension load f based on the tension measured by the load meter 13b. The suspension load f can be obtained with higher accuracy from the tension of the wire rope 8 in which the influence of f is directly reflected.

  Since the display 15 which displays the fatigue level T for each section B of the wire rope 8 obtained by the controller 14 is provided, the worker refers to the fatigue level T displayed on the display 15. The state of the wire rope 8 can always be grasped.

  In the above embodiment, the example of obtaining the fatigue level T of the wire rope 8 fed out from the winding drum 7 has been shown, but it is also possible to obtain the fatigue level of the wire rope 12 fed out from the lifting drum 11. Needless to say.

  In addition, the wire rope fatigue degree measuring method and apparatus of the crane of the present invention are not limited to the above-described embodiments, and are not limited to deck cranes, and any cranes that use wire ropes can be used. Of course, various modifications can be made within the scope of the present invention, such as being applicable.

1 Deck crane (crane)
6 Jib 7 Drum for winding
7a Winding hydraulic drive (hydraulic drive)
7b Drum rotation number detector 8 Wire rope 9 Hook 10 Cargo block 11 Lifting drum (drum)
12 Wire rope 13 Suspended load measuring instrument 13a Pressure gauge 13b Load meter 14 Controller 15 Indicator B Separating part C Suspended load f Suspended load S1 Sheave S2 Sheave S3 Sheave S4 Sheave S5 Sheave S6 Sheave S7 Sheave S8 Sheave

Claims (9)

A wire rope fatigue measurement method for a crane that lifts and lowers a suspended load with a wire rope that is unwound from a drum and wound around a sheave,
By setting a virtual delimiter part by delimiting the wire rope at regular intervals in the length direction,
Measure the suspended load acting on the wire rope,
In a state where the wire rope receives the suspension load, the number of times that each section is bent through the sheave is integrated,
Based on the suspension load and the number of bending times, determine the degree of fatigue for each section of the wire rope ,
At this time, first suspension load region F ₁ , second suspension load region F ₂ ,... Nth suspension load region F _n are set in advance, and it is determined to which region the suspension load to be measured applies. The degree of fatigue for each section of the wire rope is expressed as follows:

However, T: Fatigue degree [%] for each section of the wire rope
N _i : Actual number of bendings in the i-th suspension load region F _i
n: natural number
α _i : Bending frequency conversion factor in _i- th suspension load region F _i based on fatigue test results
N _LIM : Fatigue bending limit based on fatigue test results
A method of measuring the fatigue level of a wire rope of a crane, characterized in that it is obtained from   The method of measuring a wire rope fatigue level of a crane according to claim 1, wherein the suspension load is obtained from a hydraulic pressure of a hydraulic drive device that drives the drum.   The method of measuring a wire rope fatigue level of a crane according to claim 1, wherein the suspension load is obtained from a tension of the wire rope.   The method of measuring a wire rope fatigue level of a crane according to claim 1, wherein the number of times of bending is obtained from the number of rotations of the drum. A wire rope fatigue measurement device for a crane that lifts and lowers a suspended load with a wire rope that is unwound from a drum and wound around a sheave,
A suspension load measuring device for measuring a suspension load acting on the wire rope;
By setting a virtual delimiter by dividing the wire rope at regular intervals in the length direction, the suspension load measured by the suspension load measuring instrument is input, and the suspension load is received by the wire rope, A controller for accumulating the number of times each segmented portion is bent through the sheave, and determining a fatigue level for each segmented portion of the wire rope based on the suspension load and the number of bending steps ,
The controller stores a first suspension load region F ₁ , a second suspension load region F ₂ ,... Nth suspension load region F _n set in advance , and the suspension load to be measured is applied to which region. And determine the degree of fatigue for each section of the wire rope according to the following formula:

However, T: Fatigue degree [%] for each section of the wire rope
N _i : Actual number of bendings in the i-th suspension load region F _i
n: natural number
α _i : Bending frequency conversion factor in _i- th suspension load region F _i based on fatigue test results
N _LIM : Fatigue bending limit based on fatigue test results
An apparatus for measuring the fatigue level of a wire rope in a crane, characterized in that The crane according to claim 5, wherein the suspension load measuring device is a pressure gauge that measures a hydraulic pressure of a hydraulic drive device that drives the drum, and is configured to obtain the suspension load based on the hydraulic pressure measured by the pressure gauge. Wire rope fatigue measurement device. 6. The crane's wire rope fatigue degree according to claim 5, wherein the suspension load measuring instrument is a load meter for measuring the tension of the wire rope, and the suspension load is determined based on the tension measured by the load meter. Measuring device. The crane wire rope fatigue measurement device according to claim 5, further comprising a drum rotation number detector for detecting the rotation number of the drum. The crane's wire rope fatigue measurement device according to claim 5 , further comprising a display for displaying the fatigue level of each section of the wire rope determined by the controller.

Images