JP5486412B2 - Evaluation system and evaluation method for impact resistance of conveyor belt - Google Patents

Description

  The present invention relates to an evaluation system and an evaluation method for impact resistance of a conveyor belt, and more specifically, a conveyor belt capable of setting a test sample to a condition close to the use situation in the field and accurately evaluating impact resistance. The present invention relates to an impact resistance evaluation system and evaluation method.

  The conveyor belt is generally used by being wound around between a driving pulley and a driven pulley, and the object to be transported dropped on one end in the longitudinal direction is loaded on the belt and transported to the other end. When the object to be transported is dropped on the belt, the impact force by the dropped object to be transported acts on the conveyor belt. For this reason, repeated dropping of the object to be conveyed causes damage to the core body (canvas, steel cord, etc.) and cover rubber constituting the conveyor belt. If the transported object to be dropped has a large potential energy, such as when the weight of the transported object is large or the drop height is large, the core may be cut.

  Assuming such problems, an evaluation test of the impact resistance of the conveyor belt is performed. In the conventional evaluation test, for example, the weight is repeatedly dropped on the test sample of the conveyor belt placed on the cradle, and then the residual tensile strength of the core of the test sample is measured to determine the impact resistance. Is evaluated. However, there is a problem that an appropriate tension cannot be applied by fixing the core body at an accurate position. Moreover, although a conveyor belt is not used as an evaluation object, a method for evaluating impact resistance by causing the evaluation object to freely fall and collide with the landing surface has also been proposed (see Patent Document 1). In such a conventional method for evaluating impact resistance, it is difficult to make an evaluation consistent with actual use because the evaluation cannot be performed under conditions close to the usage situation of the conveyor belt in the field. Therefore, a means that can accurately evaluate the impact resistance of the conveyor belt has been desired.

JP 2006-200991 A

  An object of the present invention is to provide an impact resistance evaluation system and an evaluation method for a conveyor belt, which can set a test sample under conditions close to the usage conditions in the field and can accurately evaluate impact resistance. .

  In order to achieve the above object, the impact resistance evaluation system for a conveyor belt according to the present invention comprises a fixing means for fixing a core body exposed in the belt longitudinal direction from a test sample of the conveyor belt by stretching the belt in the belt longitudinal direction. , Two supports spaced apart in the longitudinal direction of the belt that support the lower surface of the test sample, a weight that freely falls to a drop position set on the test sample, and a drop impact attached to the weight An impact force sensor for detecting a force; a tension sensor for detecting a tension acting on the stretched core; and an arithmetic unit for inputting the impact force sensor and the detection data of the tension sensor; The contact area of the lower end of the weight that comes into contact with the test sample when dropped and the maximum tensile stress of the core extracted from the test sample after the weight has been dropped freely are described above. Is input to the device, the detection data of the impact force sensor and the tension sensor, and the contact area, on the basis of said maximum tensile stress, characterized in that the configuration in which the evaluation of the impact resistance.

  Further, the impact resistance evaluation method for the conveyor belt of the present invention is a state in which the core body is exposed in the longitudinal direction of the belt from the test sample of the conveyor belt and is stretched and fixed in the longitudinal direction of the belt with a preset tension. The test sample is set by supporting the lower surface of the test sample with two supports arranged at a predetermined interval in the longitudinal direction of the belt, and the set drop is set on the set test sample. The weight is dropped freely from a preset height at a position, and the drop impact force when the dropped weight collides with the test sample is detected by an impact force sensor provided on the weight, When the acting tension is detected by the tension sensor and the detection data by the impact force sensor and the tension sensor is input to the arithmetic unit, and the weight is freely dropped The contact area of the lower end portion of the weight that contacts the test sample and the maximum tensile stress of the core extracted from the test sample after the weight is freely dropped are input to the arithmetic device, and the impact force sensor and tension The impact resistance is evaluated based on the detection data of the sensor, the contact area, and the maximum tensile stress.

  According to the present invention, the core body is exposed from the test sample of the conveyor belt in the longitudinal direction of the belt and is stretched and fixed in the longitudinal direction of the belt with a preset tension, and the lower surface of the test sample is The test sample is set by supporting it with two supports arranged at a predetermined interval in the longitudinal direction of the belt, and the weight is set to the falling position set on the set test sample from the preset height. By allowing the test sample to fall freely, the test sample can be set to a tension close to the actual usage condition of the conveyor belt and the roller support state, and to a condition close to the situation where the conveyed object is dropped. Then, the detection data of the drop impact force detected by the impact force sensor provided on the weight, the detection data of the tension acting on the tensioned core detected by the tension sensor, and the test sample when the weight is freely dropped Based on the contact area of the lower end of the contacting weight and the maximum tensile stress of the core extracted from the test sample after the weight is dropped freely, the computing device evaluates the impact resistance. With respect to impact resistance, it is possible to make a highly accurate evaluation consistent with actual use.

  Here, in the evaluation system of the present invention, the interval between the supports is configured to be variable, and has a plurality of types of tip members having different bottom shapes that can be attached to and detached from the bottom end of the weight, and the plurality of types of tip members It can also be set as the structure which mounts | wears with the one front-end | tip member selected from the lower end part of the said weight. In this configuration, it is possible to evaluate the impact resistance more consistent with actual use by attaching the tip member having the lower end shape closest to the actual shape of the conveyor belt.

  In the evaluation system of the present invention, a tilting plate is provided that is tilted variably with respect to the horizontal and fixed at a set tilting angle, and the core body is stretched in the longitudinal direction of the belt on the tilting plate. The test sample, the two supports, and the fixing means may be installed.

  Further, in the evaluation method of the present invention, the set test sample is installed on a tilting plate that tilts the angle with respect to the horizontal, and the tilting plate is fixed at a preset tilting angle, The weight can be freely dropped to the dropping position.

  In the case of the configuration having the tilting plate or the method using the tilting plate, the tilting plate is used to fix the test sample at a tilting angle corresponding to the rotational travel speed of the actual conveyor belt. The weight can be freely dropped to the dropping position. Therefore, it is possible to accurately evaluate the impact resistance in consideration of the rotational travel speed of the conveyor belt.

1 is an overall schematic diagram of an impact resistance evaluation system for a conveyor belt according to the present invention. It is a top view which shows the periphery of a fixing means. It is the whole evaluation system schematic diagram which illustrates the state where the weight was dropped on the test sample. It is a whole schematic diagram which illustrates another embodiment of an evaluation system. It is the whole evaluation system outline figure which illustrates the state where the tilting board was made to incline. 6 is a graph showing the relationship between the tip end angle A of the lower end of the weight and the drop impact force F. FIG. It is a graph which shows the relationship between the front-end | tip angle F of the lower end part of a weight, and impact compressive stress CP. It is a graph which shows the relationship between the frequency | count N of weight fall, and the maximum tensile stress M of the core body taken out from the test sample after the weight drop test.

  Hereinafter, the present invention will be described with reference to the embodiments shown in the drawings.

  As illustrated in FIG. 1, the conveyor belt impact resistance evaluation system 1 of the present invention (hereinafter referred to as the evaluation system 1) is exposed from a test sample CV of a conveyor belt on a flat base 2. A pair of fixing means 4 for tensioning and fixing the core C, two supports 3 arranged at an interval L in the longitudinal direction of the belt (left and right in FIG. 1), a weight 8 for free fall, An impact force sensor 13 that is attached to the weight 8 and detects a drop impact force F, a tension sensor 12 that detects a tension T acting on the stretched core C, and detection data of the impact force sensor 13 and the tension sensor 12 Is input to the arithmetic unit 14.

  The test sample CV has a plurality of core bodies C juxtaposed in the belt width direction, and a cover rubber R provided so as to sandwich the top and bottom of the core body C. Depending on the specifications of the conveyor belt, other reinforcing members and the like are embedded in the cover rubber R. The core body C is a steel cord or various fiber cords.

  The two support bodies 3 have the same specification having an arcuate upper surface. Each support body 3 is movable along the groove part 2a formed in the base 2, and can mutually change the space | interval L to arbitrary space | intervals.

  The fixing means 4 is arranged on the outer side in the belt longitudinal direction of each support body 3. As illustrated in FIG. 2, the fixing means 4 includes a winding shaft 4b that winds up the core C, a support frame 4a that supports the winding shaft 4b, and a tension applying bolt 5 that is connected to the winding shaft 4b. Have. A through-hole 4c is provided in the cylindrical winding shaft 4b so as to be orthogonal to the axis.

  The core body C exposed from the test sample CV is held through the through hole 4c. Then, the tension applying bolt 5 is tightened, and the core C is stretched and fixed at a predetermined tension T so that the core C is wound around the outer peripheral surface of the winding shaft 4b. The tension T applied to the core C is adjusted by adjusting the tightening degree of the tension applying bolt 5.

  The winding shaft 4b is configured by, for example, assembling a semi-cylindrical divided body obtained by dividing the cylindrical body into two in the axial direction. The through hole 4c can be formed by providing a groove on the mating surface between the divided bodies. By using such a divided body, the core body C can be easily attached to the winding shaft 4b. The fixing unit 4 is not limited to the structure exemplified in the embodiment, and a fixing unit 4 that can fix the core body C exposed in the longitudinal direction of the belt from the test sample CV in the longitudinal direction of the belt can be used.

  A tension sensor 12 is provided outside one fixing means 4. The tension sensor 12 is connected to the arithmetic device 14 by a communication line. A load cell or the like can be used as the tension sensor 12. Since the detection data of the tension sensor 12 is input to the arithmetic unit 14 and displayed on the monitor 15, it is possible to confirm the tension T that stretches the core C by looking at the display on the monitor 15.

  A suspension member 10 such as a chain or a wire is suspended from an upper portion of a bowl-shaped main body frame 6 erected on the base 2. The weight 8 is suspended by the suspension member 10 via the dropping mechanism 11. When the holding of the weight 8 is released by operating the dropping mechanism 11, the weight 8 falls freely. The suspended weight 8 is inserted into a guide tube 9 fixed to the main body frame 6. The falling height H of the weight 8 can be set to an arbitrary height.

  The lower end of the weight 8 is a detachable tip member 8a. The evaluation system 1 includes not only the tip member 8a but also a plurality of types of tip members 8b to 8e having different bottom end shapes (different tip angles A). One selected from a plurality of types of tip members 8 a to 8 e having different lower end shapes is attached to the lower end portion of the weight 8.

  The impact force sensor 13 is provided midway in the longitudinal direction of the weight 8. The impact force sensor 13 is connected to the arithmetic device 14 via a communication line. A load cell or the like can be used as the impact force sensor 13.

  The computing device 14 uses a personal computer or the like, and the contact area S of the lower end portion of the weight 8 that contacts the test sample CV when the weight 8 is freely dropped to the drop position P on the test sample CV is input. . Further, the maximum tensile stress M (breaking tensile stress) of the core C taken from the test sample CV after the weight 8 is freely dropped to the drop position P is input to the arithmetic device 14.

  In the evaluation system 1 of the present invention, the computing device 14 is configured to evaluate the impact resistance based on the detection data of the impact force sensor 12 and the tension sensor 13, the contact area S, and the maximum tensile stress M. ing.

  Next, a method for evaluating the impact resistance of the conveyor belt using the evaluation system 1 will be described.

  First, the core CV is exposed in the longitudinal direction of the belt from the test sample CV, is stretched in the longitudinal direction of the belt with a preset tension T and fixed to the fixing means 4, and the lower surface of the test sample CV is A test sample CV is set by being supported by two supports 3. The tension T of the core body C is set to the same tension as that used in the field, and the distance L between the two supports 3 is set to the same distance as the distance between the support rollers in the field. The arcuate radius of the upper surface of the support 3 is preferably the same as the radius of the support roller in the field.

  The tension T acting on the heart body CV when the test sample CV is set is detected by the tension sensor 12 and input to the arithmetic unit 14. Since the tension T at the time of setting greatly affects the impact resistance of the conveyor belt, it is necessary to accurately adjust to the set tension T.

  On the set test sample CV, the weight 8 is freely dropped from a preset drop height H. The fall height H is preferably set to be the same as the input height at which the object to be conveyed is input to the conveyor belt at the site.

  The falling position P of the weight 8 can be arbitrarily set between the two supports 3 and should be adapted to the usage conditions in the field. For example, as shown in FIG. 1, the intermediate position between the two supports 3 is set to the drop position P, or the position where the support 3 is in contact with the lower surface of the test sample CV is set to the drop position P. At the lower end of the weight 8, tip members 8 a to 8 e having a lower end shape closest to the shape of the actual conveyed object of the conveyor belt may be attached.

  Thus, according to this evaluation system 1, the test sample CV is set to a condition close to the situation in which the object to be conveyed is actually dropped, with the tension and roller support being the same as the actual usage conditions of the conveyor belt. can do.

  Next, as shown in FIG. 3, the dropping mechanism 11 is operated to cause the weight 8 to fall freely. A drop impact force F (maximum impact force) when the weight 8 collides with the test sample CV is detected by the impact force sensor 13. The tension T acting on the core C at the time of the collision is detected by the tension sensor 12. Data detected by the impact force sensor 13 and the tension sensor 12 is input to the arithmetic unit 14. If necessary, a test is performed by sequentially applying a plurality of types of tip members 8a to 8e to one test sample CV.

  The computing device 14 further includes a contact area S at the lower end of the weight 8 that contacts the test sample CV when the weight 8 is freely dropped, and a heart taken out from the test sample CV after the weight 8 is freely dropped. The maximum tensile stress M of the body C is input. The contact area S varies greatly depending on the tip angle A of the tip members 8a to 8e. The mass of the weight 8, the drop height H (the distance from the lower end of the weight 8 to the surface of the test sample CV), the cover rubber R Since it varies depending on the specifications, the contact area S is grasped for various conditions.

  Here, it has been found that the impact compression stress CP acting on the conveyor belt due to the fall of the conveyed object greatly affects the damage of the core C. Therefore, the impact compressive stress CP (= F / S) is calculated using the drop impact force F and the contact area S input to the computing device 14.

  In order to measure the maximum tensile stress M, the weight 8 is dropped a predetermined number of times N, and then the test sample CV is cut along the core body C in the extending direction of the core body C. Take out. The maximum tensile stress M is obtained by chucking both ends of the core C taken out and performing a tensile test with a tensile tester. The acquired data of the maximum tensile stress M is input to the arithmetic unit 14. The maximum tensile stress Mo of the original core C that has not been subjected to the impact of the weight 8 is input to the arithmetic unit 14, and the original maximum tensile stress M is compared by comparing the acquired maximum tensile stress M with the original maximum tensile stress Mo. A reduction rate D of the maximum tensile stress M with respect to the stress Mo is calculated.

  The fact that the maximum tensile stress M of the core body C is reduced means that the core body C is damaged. Therefore, the degree of damage to the core body C can be grasped from the decrease rate D of the maximum tensile stress M. . Therefore, the same impact compression stress CP as the usage condition of the conveyor belt is set and the test is performed using the test sample CV. For example, when the acquired maximum tensile stress M is the same value (Mo) as the original, or When the reduction rate D is within a preset allowable range, it is determined that there is no problem in impact resistance of the core C (conveyor belt of the specification).

  As described above, in the present invention, the test sample CV is set to a condition close to the on-site use condition, and the resistance is determined based on the detection data of the impact force sensor 13 and the tension sensor 12, the contact area S, and the maximum tensile stress M. Evaluate impact properties. Since the evaluation is performed by paying attention to the impact compressive stress CP due to the free fall of the weight 8 and the reduction rate D of the maximum tensile stress M of the core body C, a highly accurate evaluation consistent with the actual use of the conveyor belt is performed. Can do.

  Further, the tension sensor 12 can grasp the tension T acting on the core C when the weight 8 is freely dropped and collides with the test sample CV. Therefore, it is possible to grasp how much the tension T detected at that time is with respect to the guaranteed strength of the core C. Therefore, for example, if the detected tension T is within a preset allowable range with respect to the guaranteed strength of the core C, it can be determined that there is no problem in impact resistance.

  4 and 5 illustrate another embodiment of the evaluation system 1. This embodiment is greatly different from the previous embodiment in that it includes a tilting plate 7. A rotating shaft 7 a fixed to the base 2 is provided at one end of the tilting plate 7, and an arcuate tilting plate holding frame 7 b fixed to the base 2 is provided at the other end. The tilting plate 7 has a guide projection provided at the other end of the tilting plate 7 around the rotation shaft 7a as a guide hole 7c formed in the tilting plate holding frame 7b so that the angle Ah with respect to the horizontal. Can be variably tilted. The tilt plate 7 is configured to be fixed at an arbitrarily set tilt angle Ah.

  On the tilting plate 7, a test sample CV in which a core C is stretched in the belt longitudinal direction, two supports 3, and a fixing means 4 are installed. Accordingly, the test sample CV set on the two supports 3 by stretching the core C with a predetermined tension T can be fixed on the base 2 at any set inclination angle Ah. Yes. Other configurations are the same as those of the previous embodiment. In this embodiment, the angle of the surface of the test sample CV can be arbitrarily set with respect to the weight 8 that freely falls vertically.

  At the site where the conveyor belt is used, the object to be transported is dropped onto the belt while the conveyor belt is rotating. Therefore, the object to be conveyed freely falls on the test sample CV while having the same speed component as the rotational traveling speed of the conveyor belt in the direction opposite to the rotational traveling direction of the conveyor belt. In this embodiment, as shown in FIG. 5, the test sample CV is fixed at an inclination angle Ah corresponding to the rotational travel speed of the actual conveyor belt using the tilting plate 7, and the weight 8 is moved to the drop position P. Can fall freely. Therefore, it is possible to accurately evaluate the impact resistance in consideration of the rotational travel speed of the conveyor belt.

  Using the test system illustrated in FIG. 1, with respect to a test sample CV having the same specifications, only the tip angle A of the weight 8 is changed in six ways (samples 1 to 6), and the weight 8 is freely dropped to reduce the weight. The drop impact force F when 8 collides with the test sample CV is detected by the impact force sensor 13, and the result is shown in FIG. The test sample CV has three cores C of steel cords (original maximum tensile stress Mo is 1300 MPa), and the thickness of the upper and lower cover rubbers R is 4 mm, the belt length is 750 mm, and the belt width is 30 mm. . The distance between the supports 3 is 300 mm, the intermediate position of the supports 3 is set to the drop position P, the core C is stretched with a tension of 2.7 kN, and the weight 8 having a weight of 5 kg is freely dropped at a drop height H of 500 mm. It was. From the results of FIG. 6, it can be seen that there is almost no difference in the drop impact force F due to the difference in the tip angle A of the weight 8.

  Here, at each tip angle A, the impact when the weight 8 collides with the test sample CV using the contact area S of the lower end portion of the weight 8 that contacts the test sample CV when the weight 8 is freely dropped. The compressive stress CP (= F / S) is calculated by the arithmetic unit 14, and the result is shown in FIG. From the results of FIG. 7, it can be seen that the smaller the tip angle A of the weight 8, the smaller the contact area S, and the greater the impact compressive stress CP.

  Next, the maximum tensile stress M of the core C taken out from the test sample CV after the weight 8 is freely dropped for a preset number N is measured, and the maximum tensile stress M with respect to the original maximum tensile stress Mo is measured. The state is shown in FIG.

  From the results of FIG. 8, in samples 1 and 2 having a small tip angle A (contact area S), the maximum tensile stress M is greatly decreased and the decrease rate D (= (Mo−M) / Mo) is large. I understand. When the number of drops N is 50, the decrease rates D of the samples 1 and 2 are about 60% and 50%, respectively. That is, it can be seen that the greater the impact compression force CP due to the free fall of the weight 8, the easier the core C is damaged. On the other hand, it can be seen that when the tip angle A is increased to some extent, damage to the core C can be effectively suppressed.

DESCRIPTION OF SYMBOLS 1 Evaluation system 2 Base 2a Groove part 3 Support body 4 Fixing means 4a Support frame 4b Winding shaft 4c Through hole 5 Tensioning bolt 6 Main body frame 7 Tilt plate 7a Rotating shaft 7b Tilt plate holding frame 7c Guide hole 8 Weights 8a to 8e Tip Member 9 Guide tube 10 Suspension member 11 Drop mechanism 12 Tension sensor (load cell)
13 Impact force sensor (load cell)
14 Computing Device 15 Monitor CV Test Sample C Core R Cover Rubber A Tip Angle

Claims (5)

  A fixing means that stretches and fixes the core body exposed in the longitudinal direction of the belt from the test sample of the conveyor belt in the longitudinal direction of the belt, and 2 arranged at intervals in the longitudinal direction of the belt that supports the lower surface of the test sample. Two supports, a weight that freely falls to the drop position set on the test sample, an impact force sensor that is attached to the weight and detects a drop impact force, and a tension that acts on the tensioned body A tension sensor, and an arithmetic unit to which the detection data of the impact force sensor and the tension sensor are input, the contact area of the lower end of the weight that contacts the test sample when the weight is freely dropped, and the weight The maximum tensile stress of the core body taken out from the test sample after free-falling is input to the arithmetic unit, the detection data of the impact force sensor and the tension sensor, and the contact The area, based on the said maximum tensile stress, the conveyor belt impact resistance evaluation system, characterized in that the configuration in which the evaluation of the impact resistance.   The support is configured to have a variable interval, and has a plurality of types of tip members having different bottom end shapes that can be attached to and detached from the bottom end of the weight, and one tip member selected from the plurality of types of tip members is attached to the weight. The impact resistance evaluation system for a conveyor belt according to claim 1, wherein the system is attached to the lower end of the conveyor belt.   A tilting plate that is tilted variably with respect to the horizontal and fixed at a set tilting angle is provided, and a test sample in which the core body is stretched in the longitudinal direction of the belt on the tilting plate; The impact resistance evaluation system for a conveyor belt according to claim 1 or 2, wherein two supports and the fixing means are installed.   The core body is exposed in the longitudinal direction of the belt from the test sample of the conveyor belt and is stretched and fixed in the longitudinal direction of the belt with a preset tension, and the lower surface of the test sample is preliminarily placed in the longitudinal direction of the belt. A test sample is set by supporting it with two supports arranged at a set interval, and a weight is freely dropped from a preset height to a drop position set on the set test sample, A drop impact force when the dropped weight collides with the test sample is detected by an impact force sensor provided on the weight, and a tension acting on the stretched core is detected by a tension sensor, and the impact force sensor and The detection data by the tension sensor is input to the arithmetic unit, and the contact area of the lower end of the weight that contacts the test sample when the weight is freely dropped, and the The maximum tensile stress of the core body taken out from the test sample after free-falling is input to the arithmetic unit, the detection data of the impact force sensor and the tension sensor, the contact area, and the maximum tensile stress. A method for evaluating the impact resistance of a conveyor belt, characterized in that the impact resistance is evaluated based on the above.   The set test sample is placed on a tilting plate that tilts in a variable angle with respect to the horizontal, the tilting plate is fixed at a preset tilting angle, and the weight is freely dropped to the dropping position. The method for evaluating impact resistance of a conveyor belt according to claim 4.

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