Cable thermal elongation testing device and control method thereof

Abstract

The present invention relates to a cable thermal elongation test device and a control method thereof, and relates to the field of cable testing. The test chamber is provided with a heating chamber and a display screen. A hanging member in the heating chamber is detachably connected to the upper end of a test member, and the test member includes a cable sample and two clamping members provided at the upper and lower ends of the cable sample. A load member, which is slidably connected to a guide rod in the heating chamber, is provided directly below the hanging member and detachably connected to the lower end of the test member. A conductive member on the load member is in sliding contact with the outer peripheral surface of a resistor extending vertically and electrically conductive, so that the vertical distance between the conductive member and the upper end of the resistor, the length of the cable sample, and the energized length of the resistor are equal. An ammeter, a DC power supply, the conductive member, and the upper end of the resistor are electrically connected in a closed loop. A voltmeter, the conductive member, and the upper end of the resistor are electrically connected in a closed loop. A control processor calculates the length of the cable sample based on the current value, the voltage value, and the resistance per unit length of the resistor, and displays the result on the display screen. The present invention provides a test with high accuracy, safety, and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of cable testing, and in particular to a cable thermal elongation testing device and a control method thereof. Background Art

[0002] The thermal elongation test is an important test to evaluate the deformation resistance of cable insulation or sheath materials (such as cross-linked polyethylene) under the dual effects of high temperature and mechanical load. It is mainly used to verify whether the material has reached the cross-linking degree specified in the standard to ensure that the cable will not be excessively deformed or fail due to thermal stress problems during long-term operation.

[0003] When using the existing cable thermal extension test device, the upper end of the prepared cable insulation or sheath material sample is fixed in an aging box, and a certain load such as a weight is hung on the lower end of the sample to make the sample in a vertical hanging state; the aging box is closed, and the temperature in the aging box is raised to the set test temperature, such as 200°C, and the timing is started. When the accumulated time reaches the set test time, such as 15 minutes, the stretched gauge length of the sample (i.e., the length L1 between the stretched gauge lines) is read, so that the thermal elongation E (or elongation under load) can be calculated based on the original gauge length (i.e., the original length L0 between the gauge lines) and the stretched gauge length.

[0004] However, if the aging box does not have an observation window for test personnel to read the data, or the observation window is difficult for test personnel to read the data directly and clearly, the aging box must be opened to read the data, which will bring inconvenience to the test work and easily cause test personnel to be burned by the high temperature of the aging box. Moreover, the test personnel use visual inspection to read the gauge data measured by the ruler, which will cause the accuracy of the test results to be easily affected by the measurement error of the naked eye and decrease. In addition, if a visual system is used to obtain the elongation data of the sample, the cost of the equipment will increase significantly. Therefore, it is urgent to develop a new cable thermal extension measurement device that can conveniently, directly, clearly and accurately obtain test data at a low cost. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a cable thermal elongation test device and control method, which enable testers to obtain test data quickly and clearly, avoiding the accuracy of test results that may be reduced due to visual measurement errors, and protecting testers from high-temperature burns. Furthermore, the device is low-cost.

[0006] A first embodiment of the present invention provides a cable thermal elongation testing device, comprising:

[0007] The test box is provided with a heating chamber and a display screen, wherein a guide rod extending in an up-down direction is provided in the heating chamber;

[0008] a hanging member fixedly disposed in the heating chamber for detachably connecting to the upper end of a test piece, wherein the test piece includes a cable sample and two clamping members fixed to the upper and lower ends of the cable sample;

[0009] a load member, slidably connected to the guide rod up and down, and disposed directly below the suspension member, for detachably connecting to the lower end of the test piece;

[0010] A measurement system comprising a resistor, a conductive member, a DC power supply, an ammeter, and a voltmeter, wherein the resistor extends in a vertical direction and is fixedly disposed within the heating chamber, the conductive member being connected to the load member and in sliding contact with the outer circumference of the resistor and conducting electricity, such that a vertical distance between the conductive member and the upper end of the resistor is equal to the length of the cable sample, the ammeter, the DC power supply, the conductive member, and the upper end of the resistor being electrically connected in a closed loop so that the ammeter can collect current values, and the voltmeter, the conductive member, and the upper end of the resistor being electrically connected in a closed loop so that the voltmeter can collect voltage values;

[0011] A control processor is electrically connected to the ammeter, the voltmeter and the display screen, and is used to calculate the energized length of the resistor according to the current value, the voltage value and the resistance per unit length of the resistor, and control the display screen to display the length value of the cable sample, wherein the energized length of the resistor is the upper and lower distance between the conductive member and the upper end of the resistor.

[0012] According to the cable thermal elongation test device of the embodiment of the first aspect of the present invention, there are at least the following beneficial effects: when the upper and lower ends of the test piece are connected to the suspension piece and the load piece respectively, the test piece is in a suspended state in the heating chamber of the test chamber, at this time, the conductive piece on the load piece contacts the outer surface of the resistor piece; when the test chamber is closed and the temperature in the heating chamber reaches the set temperature, the thermal elongation of the cable sample can be tested under high temperature and mechanical load conditions. During this process, the load piece and the conductive piece can move downward according to the elongation of the cable sample, thereby changing the contact position between the conductive piece and the resistor piece in the vertical direction, so that a mathematical relationship can be established between the energized length of the resistor piece and the length value of the cable sample; at the same time, the control processor can receive data collected by the ammeter and the voltmeter, the ammeter can detect the current value passing through the resistor piece, and the voltmeter can detect the voltage value between the upper end of the resistor piece and the contact point between the resistor piece and the conductive piece; when the test time reaches the set time, the control processor can quickly calculate the energized length of the resistor piece based on the received current value, voltage value and the known unit length resistance value of the resistor piece.

[0013] Since the upper and lower distances between the upper ends of the conductive element and the resistor are designed to be equal to the length of the cable sample, and the energized length of the resistor is the upper and lower distances between the conductive element and the upper ends of the resistor, the calculated energized length of the resistor is the length of the cable sample. Finally, the length of the cable sample during the thermal extension test is clearly displayed on the display screen, making it easier for testers to accurately calculate the thermal extension rate of the cable based on the previously measured original length of the cable sample and the length of the cable sample during the thermal extension test.

[0014] By adopting such a unique design, it is convenient for test personnel to operate and obtain the data of the thermal elongation test conveniently, and the test accuracy can be improved, preventing the error caused by the naked eye measurement method from causing the accuracy of the test results to decrease. At the same time, it can prevent test personnel from being easily burned by the high-temperature test chamber, improve the safety of use, and reduce the manufacturing cost, so that the cable thermal elongation test device can be widely used.

[0015] In some embodiments of the present invention, the resistor is cylindrical, two resistors are provided and spaced apart in the horizontal direction, the conductive member is provided with two contacts, the conductive member is located between the two resistors so that the two contacts are in sliding contact with the outer circumferences of the two resistors and conduct electricity, the ammeter, the DC power supply, the upper end of one of the resistors, the conductive member, and the upper end of the other resistor are electrically connected in a closed loop to form a first loop, and the voltmeter, the upper end of one of the resistors, the conductive member, and the upper end of the other resistor are electrically connected in a closed loop to form a second loop; and / or,

[0016] The guide rod is a round rod, and at least one guide rod is provided. The load member is provided with a guide sleeve slidably connected to the guide rod.

[0017] In some embodiments of the present invention, the test chamber includes a chamber body and a chamber door, wherein the chamber door is located on one side of the chamber body along a first direction and is movably connected to the chamber body to open and close the opening of the heating chamber, and the lower end of the suspension member is provided with a first slot for inserting the upper end of the test piece along the first direction, and the upper end of the load member is provided with a second slot for inserting the lower end of the test piece along the first direction, and the first direction is perpendicular to the up and down directions.

[0018] In some embodiments of the present invention, the cross-section of the first slot is T-shaped, and the cross-section of the second slot is inverted T-shaped.

[0019] In some embodiments of the present invention, the cable thermal elongation testing device also includes a reset adjustment mechanism, which includes a first driving member and a lifting member. The lifting member is arranged in the heating chamber and is located below the load member. The first driving member is used to drive the lifting member to move in the up and down directions so that the lifting member lifts the load member to a set position, so that the lower end of the test member can be inserted into the second slot along the first direction.

[0020] In some embodiments of the present invention, the first driving member is a servo electric cylinder and is disposed outside the heating chamber. The output end of the first driving member extends into the heating chamber and is fixedly connected to the lifting member.

[0021] In some embodiments of the present invention, the cable thermal elongation testing device also includes a second driving member, which is used to drive the box door to open and close. The control processor is electrically connected to the reset adjustment mechanism and the second driving member, respectively, and is used to control the second driving member to drive the box door to open after the reset adjustment mechanism drives the load member to move up to the set position.

[0022] In some embodiments of the present invention, the cable thermal elongation testing device also includes a temperature sensor, which is used to collect the real-time temperature in the heating chamber. The control processor is electrically connected to a timing unit, and the control processor is electrically connected to the temperature sensor. The control processor is used to control the timing unit to measure the test time when the real-time temperature reaches the set temperature, and collect the current value and the voltage value when the test time reaches the set time.

[0023] In some embodiments of the present invention, the measurement system also includes a control switch, wherein the control switch, the ammeter, the DC power supply, the conductive member and the upper end of the resistive member are electrically connected in a closed loop, and the control switch is electrically connected to the control processor, and the control processor is used to control the control switch to be turned on after the second driving member drives the box door to close.

[0024] A second embodiment of the present invention provides a control method for a cable thermal elongation test device, which is applied to the cable thermal elongation test device as described in the first embodiment, and includes the following steps:

[0025] When the test piece is connected to the suspension piece and the load piece respectively and the temperature of the heating chamber reaches a set temperature, controlling the timing unit to operate to count the test time;

[0026] When the test time reaches the set time, the current current value of the ammeter and the current voltage value of the voltmeter are collected;

[0027] Calculating the energized length of the resistor according to the current current value, the current voltage value, and the resistance per unit length of the resistor;

[0028] The display screen is controlled to display the length value of the cable sample.

[0029] According to the control method of the cable thermal elongation test device of the second aspect embodiment of the present invention, there are at least the following beneficial effects: after the test piece is installed in the test box, the test box is closed and the temperature is increased so that the temperature in the heating chamber can reach the set temperature for the thermal elongation test; when the temperature in the heating chamber reaches the requirement, the test time can be counted by the timing unit, so that the test piece can be subjected to the thermal elongation test under the action of high temperature and mechanical load; when the test time accumulates to the set time, the control processor can collect the current current value detected by the ammeter and the current voltage value detected by the voltmeter, and quickly calculate the energized length of the resistor based on the current current value, the current voltage value and the known resistance value per unit length of the resistor.

[0030] Since the upper and lower distances between the upper ends of the conductive element and the resistive element are designed to be equal to the length of the cable sample, and the energized length of the resistive element is equal to the upper and lower distances between the upper ends of the conductive element and the resistive element, the energized length of the resistive element calculated by the control processor is the length of the cable sample. Finally, the control processor controls the operation of the display screen and clearly displays the length of the cable sample after extension during the thermal extension test through the display screen, so that the test personnel can accurately calculate the thermal elongation of the cable based on the previously measured original length of the cable sample and the length of the cable sample during the thermal extension test.

[0031] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 2. This is a front view of a cable thermal elongation testing device according to an embodiment of the present invention;

[0033] Figure 2 2 is a schematic diagram of the internal structure of a cable thermal elongation testing device provided in accordance with an embodiment of the present invention;

[0034] Figure 3 2 is a schematic structural diagram of a cable thermal elongation test device according to another embodiment of the present invention, in which a conductive member is in sliding contact with two resistive members respectively;

[0035] Figure 4This is a structural diagram of a reset adjustment mechanism in a cable thermal elongation testing device provided according to another embodiment of the present invention;

[0036] Figure 5 is a schematic diagram of the internal structure of a cable thermal elongation testing device provided in accordance with another embodiment of the present invention;

[0037] Figure 6 2 is a schematic diagram of the electrical connection structure of the measurement system in the cable thermal elongation test device provided by an embodiment of the present invention;

[0038] Figure 7 2 is a schematic diagram of the electrical connection structure of the measurement system in the cable thermal elongation test device provided in another embodiment of the present invention;

[0039] Figure 8 1 is a schematic diagram of the electrical connection structure of the measurement system in the cable thermal elongation test device provided in another embodiment of the present invention;

[0040] Figure 9 1 is a schematic structural diagram of a cable thermal elongation test device provided according to an embodiment of the present invention, in which a control processor is electrically connected to a voltmeter, an ammeter, and a display screen respectively;

[0041] Figure 10 1 is a schematic structural diagram of a cable thermal elongation test device according to another embodiment of the present invention, in which a control processor is electrically connected to a temperature sensor, a voltmeter, an ammeter, a display screen, a timing unit, a reset adjustment mechanism, and a second driving member;

[0042] Figure 11 1 is a schematic structural diagram of a cable thermal elongation test device according to another embodiment of the present invention, in which a control processor is electrically connected to a temperature sensor, a voltmeter, an ammeter, a display screen, a timing unit, a reset adjustment mechanism, a second drive element, and a control switch;

[0043] Figure 12 4 is a flow chart of a control method of a cable thermal elongation testing device provided according to an embodiment of the present invention.

[0044] Figure numerals: 100, test chamber; 110, box body; 111, heating chamber; 120, chamber door; 130, observation window; 140, display screen; 151, air inlet member; 152, air outlet member; 153, air chamber; 154, heating and air supply device; 210, suspension member; 211, first slot; 220, load member; 221, second slot; 222, weight; 230, guide rod; 240, guide sleeve; 310, resistor member; 320, conductive member; 400, reset adjustment mechanism; 410, first driving member; 420, lifting member; 510, cable sample; 520, clamping member; 610, first horizontal line; 620, second horizontal line; 630, third horizontal line; 640, fourth horizontal line. DETAILED DESCRIPTION

[0045] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0046] In the description of the present invention, it should be understood that a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0047] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0048] Reference below Figures 1 to 12 A cable thermal elongation testing device and a control method thereof are described according to an embodiment of the present invention.

[0049] like Figures 1 to 11 As shown, the cable thermal elongation testing device according to the embodiment of the first aspect of the present invention can be used in the thermal elongation testing of cables. It can provide test personnel with convenient and clear access to cable test data, avoid the accuracy of thermal elongation test results being reduced due to errors in naked eye measurement, and ensure the high accuracy of the test structure. At the same time, it can also prevent test personnel from being burned by high temperature, thereby improving the safety of use. Moreover, the manufacturing cost is low.

[0050] The cable thermal elongation test device has a first direction, a second direction, and an up-down direction that are perpendicular to each other. In this embodiment, it is assumed that the first direction is the front-back direction and the second direction is the left-right direction.

[0051] like Figures 1 to 11 As shown, the cable thermal elongation testing device includes a test box 100, a suspension member 210, a load member 220, a measurement system, and a control processor.

[0052] like Figure 1 and Figure 2 As shown, the test box 100 is provided with a heating chamber 111 and a display screen 140. Specifically, the test box 100 includes a box body 110 and a door 120, wherein the door 120 is located on one side of the box body 110 along the first direction, and the door 120 is movably connected to the box body 110 to open and close the opening of the heating chamber 111. The heating chamber 111 provides a closed space for high-temperature testing of the test piece. A guide rod 230 is provided in the heating chamber 111, and the length of the guide rod 230 extends in the up and down directions. Both ends of the guide rod 230 are fixedly connected to the test box 100, so that the guide rod 230 remains stable and motionless in the heating chamber 111. The number of guide rods 230 is not limited to one. The display screen 140 is located on the outer surface of the test box 100, such as on the front side of the box body 110.

[0053] It is understandable that the test piece includes a cable sample 510 and two clamping members 520, and the two clamping members 520 are respectively fixed to the upper and lower ends of the cable sample 510. The cable sample 510 can be designed into a dumbbell shape during preparation. The clamping member 520 can be formed by two clamping plates connected by bolts, and the two clamping plates can effectively and stably clamp and fix the end of the cable sample 510. The cross-sectional shape of the guide rod 230 can be square or circular. After the test piece is placed in the heating chamber 111, the box door 120 is closed so that the test piece is in a high-temperature and closed test environment. The display screen 140 has the function of displaying data. Of course, the display screen 140 can be a display touch screen, which is configured with functions such as command input and data viewing.

[0054] The interior of the test box 100 is hollow and has a heating chamber 111 and an air chamber 153. The heating chamber 111 and the air chamber 153 are spaced apart. In this embodiment, Figure 2As shown, the air cavity 153 is located at the rear of the heating cavity 111. A partition is provided between the air cavity 153 and the heating cavity 111. An air inlet 151 is provided on the upper part of the partition, and an air outlet 152 is provided on the lower part of the partition. Both the air inlet 151 and the air outlet 152 are provided with air holes, so that the air cavity 153 can be connected to the heating cavity 111. A heating air supply device 154 is provided in the air cavity 153. The heating air supply device 154 includes a blower and a heating element. The heating element can be a heating rod or a heating plate. When the blower and the heating element are working, the air in the heating cavity 111 can flow into the air cavity 153 through the air inlet 151, and after absorbing the heat generated by the heating element, it flows back into the heating cavity 111 through the air outlet 152, thereby increasing the air temperature in the heating cavity 111 so that the air temperature can reach the test temperature and remain basically unchanged, so that the test box 100 can provide a constant temperature test space for the test piece.

[0055] Of course, it is not excluded that a plurality of heating tubes are provided in the heating chamber 111 to increase the air temperature in the heating chamber 111. In addition, an observation window 130 may be provided on the door 120 to facilitate the test personnel to clearly observe the situation in the heating chamber 111 through the observation window 130.

[0056] The hanging member 210 is fixedly arranged in the heating chamber 111 so that the hanging member 210 can be used to be detachably connected to the upper end of the test piece. Figure 2 As shown, the upper end of the hanging member 210 can be fixed to the inner top surface of the heating chamber 111 by means of bolt connection or the like. The lower end of the hanging member 210 is provided with a first card slot 211, and the first card slot 211 can be used for inserting the upper end of the test piece along the first direction. In this embodiment, the cross-sectional shape of the first card slot 211 is T-shaped when viewed along the first direction, and the upper end of the clamping member 520 located on the upper side of the cable sample 510 is designed as a T-shaped protrusion so that the clamping member 520 can enter and exit the first card slot 211 along the first direction. When the upper end of the test piece extends into the first card slot 211 along the first direction, the hanging member 210 can provide a certain support to the test piece, so that the test piece is in a suspended state.

[0057] The load member 220 is connected to the guide rod 230 in a sliding manner in the up and down direction, so that the load member 220 can move up and down stably along the guide rod 230. Figure 2As shown, in this embodiment, the guide rod 230 is a round rod, and the load member 220 is provided with a guide sleeve 240 that fits over the guide rod 230, enabling a sliding connection between the guide sleeve 240 and the guide rod 230. At least one guide rod 230 is provided. Furthermore, the load member 220 is positioned directly below the hanger 210, enabling it to be removably connected to the lower end of the test piece. Specifically, the upper end of the load member 220 is provided with a second slot 221, which allows the lower end of the test piece to be inserted along a first direction. In this embodiment, the cross-section of the second slot 221 is an inverted T-shape when viewed along the first direction. The lower end of the clamping member 520, located below the cable sample 510, is designed with an inverted T-shaped protrusion to facilitate movement of the clamping member 520 into and out of the second slot 221 along the first direction. When the lower end of the test piece extends into the second slot 221 along the first direction, the load member 220 can apply a certain load to the test piece.

[0058] It is understandable that the suspension member 210 and the load member 220 can be made of materials such as metal or plastic. The specific shapes of the suspension member 210 and the load member 220 can be designed according to actual conditions and are not specifically limited here. The total weight of the load member 220 meets the load test requirements of the cable sample 510. A weight 222 can be hung below the load member 220, and a weight 222 of appropriate weight can be hung on the load member 220 according to the test conditions. The guide rod 230 can be set behind the load member 220 and the suspension member 210, or it can be set on the left or right side of the load member 220 and the suspension member 210. The outer surface of the guide rod 230 is smooth, and the load member 220 is installed with a guide sleeve 240, so the friction between the guide rod 230 and the load member 220 is very small and can be ignored.

[0059] The measuring system includes a resistor 310, a conductive element 320, a DC power supply, an ammeter and a voltmeter. Figure 2 As shown, the length of the resistor 310 extends in the vertical direction. Furthermore, the resistor 310 is fixedly disposed within the heating chamber 111. Specifically, the resistor 310 can be fixedly connected to the test chamber 100 via a connector such as a fixing clamp, so that the resistor 310 remains in a stable vertical position. The conductive member 320 is connected to the load member 220 and is fixed relative to the load member 220. The conductive member 320 and the outer peripheral surface of the resistor 310 are in sliding contact and mutually conductive, so that the vertical distance H between the upper ends of the conductive member 320 and the resistor 310 is equal to the length of the cable sample 510.

[0060] It is understood that resistor element 310 is cylindrical and can be made of materials such as manganese copper, constantan, platinum resistor, or nickel-chromium alloy. Preferably, resistor element 310 is made of constantan. Constantan has an applicable temperature range up to 500°C. Constantan exhibits a nearly linear resistance increase at high temperatures. Constantan's resistivity is excellently stable between 25°C and 300°C. Constantan maintains good high-temperature stability under the test temperature conditions, meeting the requirements of cable thermal elongation testing. The cable thermal elongation test is conducted under constant temperature conditions. In this embodiment, the set temperature can be set to 200°C ± 0.5°C. The resistance change of resistor element 310 made of constantan is extremely small (approximately ± 0.001%) with a temperature difference of ± 0.5°C, which is negligible. In this case, the resistance per unit length of resistor element 310 can be determined based on the resistance value of resistor element 310 at 200°C. Of course, the temperature difference can be further reduced to minimize its impact on resistor element 310.

[0061] In addition, the resistor 310 may also be made of nickel-chromium alloy, whose resistance variation is approximately linear within the range of 25° C. to 300° C.

[0062] For resistors 310 whose resistance changes linearly or approximately linearly with temperature, the resistance of the resistor 310 can be calculated based on existing resistance-temperature equations, and the resistance per unit length of the resistor 310 can then be calculated based on the known length of the resistor 310. Alternatively, before conducting a cable thermal extension test, the resistance of the resistor 310 at the test temperature can be experimentally obtained, and the resistance per unit length of the resistor 310 can then be calculated based on the known length of the resistor 310. To minimize the impact of temperature fluctuations on the resistance value and ensure negligible changes in resistance within the temperature fluctuation range, it is preferred to select materials with good stability for the resistor 310.

[0063] The resistance per unit length of the resistor 310 is obtained in the above manner. Furthermore, the resistance per unit length of the resistor 310 is known and constant and can be stored in the control processor. For different test temperatures, the resistance per unit length of the resistor 310 at different test temperatures can be stored in the control processor.

[0064] The resistor 310 can be located behind, to the left, or to the right of the load 220. The outer surface of the resistor 310 is smooth, and the conductive member 320 has contacts that are in contact with the outer surface of the resistor 310 and can conduct electricity to each other. The friction between the conductive member 320 and the resistor 310 is very small and can be ignored; in addition, the contact resistance between the conductive member 320 and the resistor 310 is very small and can be ignored, so as to avoid affecting the thermal elongation test results. An electrical insulation design can be adopted between the load 220 and the conductive member 320, such as providing an electrical insulation layer at the connection between the two. The weight of the load 220 and the conductive member 320 is constant.

[0065] like Figure 6 As shown, the ammeter, DC power supply, conductive member 320 and the upper end of the resistor 310 are connected in a closed loop so that the ammeter can collect current values; the voltmeter, conductive member 320 and the upper end of the resistor 310 are connected in a closed loop so that the voltmeter can collect voltage values.

[0066] It can be understood that the upper end of the resistor 310, the ammeter, the DC power supply and the conductive member 320 are connected in sequence through wires, and the conductive member 320 is in contact with the outer peripheral surface of the resistor 310 and is conductive, so that the four can together form a first circuit, and the ammeter can detect the current value flowing through the resistor 310 in real time. Of course, a useful electrical load can be connected in series to the first circuit, such as a heating element or a lamp. The upper end of the resistor 310, the voltmeter and the conductive member 320 are connected in sequence through wires, and the conductive member 320 is in contact with the outer peripheral surface of the resistor 310 and is conductive, so that the three can together form a second circuit, and the voltmeter can detect the current value at both ends of the resistor 310 in real time. The wire connected to the conductive member 320 can be a lightweight wire, such as an existing ultra-fine stranded wire or silicone micro wire, so that the weight of the wire can be ignored to avoid affecting the thermal elongation test results.

[0067] The control processor is electrically connected to the ammeter, voltmeter and display screen 140 through wires, such as Figure 9 As shown, the control processor can receive real-time data collected from the ammeter and voltmeter and can send control instructions to the display screen 140. The control processor can be used to calculate the energized length of the resistor 310 based on the current value collected by the ammeter, the voltage value collected by the voltmeter, and the known resistance per unit length of the resistor 310 using the voltage, current, and resistance formula, where the resistance is equal to the product of the resistance per unit length of the resistor 310 and the energized length of the resistor 310, and the energized length of the resistor 310 is the vertical distance H between the conductive member 320 and the upper end of the resistor 310, all of which are equal to the length of the cable sample 510. The control processor can also control the display screen 140 to display the length of the cable sample 510.

[0068] It is understood that the control processor can be an integrated motherboard, a 51 single-chip microcomputer, or a PLC controller, etc., which has programmable, logic control, and data processing functions. The specific model of the control processor is not limited. The set values ​​of the resistor 310, such as the resistance per unit length, the set time, and the set temperature, can be stored in a data storage unit integrated into the control processor.

[0069] like Figure 2 As shown, the position of the hanger 210 in the heating chamber 111 is known and unchanged. When the upper end surface of the test piece and the inner top surface of the first slot 211 of the hanger 210 are both on the first horizontal line 610, the upper end of the test piece can be inserted into the first slot 211 along the first direction, thereby completing the connection between the test piece and the hanger 210. At this time, the upper end surface of the cable sample 510 and the upper end surface of the resistor 310 are both on the second horizontal line 620, that is, the two are flush on the horizontal plane. The load member 220 is then moved up to a set height. A stopper can be provided to ensure that the load member 220 is in position. This ensures that the lower end surface of the test piece and the inner bottom surface of the second slot 221 of the load member 220 are both aligned on the fourth horizontal line 640. The lower end of the test piece can then be inserted into the second slot 221 along the first direction, completing the connection between the test piece and the load member 220. At this point, the lower end surface of the cable sample 510 and the center of the conductive member 320 are both aligned on the third horizontal line 630, meaning that they are flush on the horizontal plane. Therefore, the vertical distance H between the contact point between the resistor 310 and the conductive member 320 and the upper end surface of the resistor 310 is equal to the vertical length of the cable sample 510.

[0070] When the cable sample 510 is subjected to a thermal elongation test under high temperature and mechanical load, the load member 220 and the conductive member 320 move downward as the cable sample 510 extends downward, thereby adjusting the contact and conductive position between the conductive member 320 and the resistor 310, thereby increasing the energized length of the resistor 310.

[0071] In the process of using the cable thermal elongation test device provided by the embodiment of the first aspect of the present invention, after the upper and lower ends of the test piece are manually connected to the suspension piece 210 and the load piece 220 respectively, the test piece is in a stable suspension state in the heating chamber 111 of the test box 100. At this time, the conductive piece 320 on the load piece 220 contacts the outer surface of the resistor 310 and can conduct electricity to each other; when the test box 100 is in a closed state and the temperature in the heating chamber 111 reaches the set temperature, the thermal elongation of the cable sample 510 can be tested under high temperature and mechanical load conditions. During this process, the load piece 220 and the conductive piece 320 can move downward according to the elongation of the cable sample 510, thereby changing the contact position between the conductive piece 320 and the resistor 310 in the upper and lower directions, so that the energized length of the resistor 310 and the length value of the cable sample 510 can establish a certain mathematical relationship, that is, the energized length of the resistor 310 is equal to the length value of the cable sample 510.

[0072] At the same time, the control processor can receive real-time data transmitted from the ammeter and the voltmeter. The ammeter can detect the current value flowing through the resistor 310, and the voltmeter can detect the voltage value between the upper end of the resistor 310 and the contact point between the resistor 310 and the conductive member 320. When the test time reaches the set time, the control processor can quickly calculate the energized length of the resistor 310 based on the current value, voltage value and the known unit length resistance of the resistor 310 received at this time, and based on the existing Ohm's law formula and the variable resistance value of the resistor 310 being the product of the energized length of the resistor 310 and the unit length resistance of the resistor 310.

[0073] Since the vertical distance H between the upper ends of the conductive element 320 and the resistor 310 is designed to be equal to the length of the cable sample 510, and the energized length of the resistor 310 is the vertical distance H between the upper ends of the conductive element 320 and the resistor 310, the calculated energized length of the resistor 310 is the length of the cable sample 510. Finally, the control processor controls the display screen 140 to clearly display the length L1 of the cable sample 510 during the thermal elongation test. This facilitates the tester to accurately calculate the thermal elongation of the cable based on the previously measured original length L0 of the cable sample 510 and the length L1 of the cable sample 510 during the thermal elongation test. It can be understood that the calculation formula for the thermal elongation E of the cable is E = (L1-L0) * 100% / L0.

[0074] The first aspect of the embodiment of the present invention adopts such a unique structural design, which makes it convenient for test personnel to operate and obtain data from thermal elongation tests, and can improve the accuracy of the test, prevent the errors caused by the naked eye measurement method from causing the accuracy of the test results to decrease. At the same time, it can prevent test personnel from being easily scalded by the test box 100 with a high heating temperature, improve the safety of use, and reduce manufacturing costs, so that the cable thermal elongation test device can be widely used.

[0075] In some embodiments, as Figure 3 and Figure 7 As shown, when viewed from above and below, the resistor 310 is cylindrical. Two resistors 310 are provided, and the two resistors 310 are spaced apart in the horizontal direction. The two resistors 310 can be spaced apart in the first direction or in the second direction. The conductive member 320 has two contacts, which are respectively arranged corresponding to the two resistors 310. The conductive member 320 is fixed to the load member 220 and is located between the two resistors 310 so that the two contacts are in sliding contact with the outer circumferences of the two resistors 310 and conduct electricity. At this time, the conductive member 320 acts like a bridge, allowing electrons to flow from one resistor 310 to the other resistor 310 through the conductive member 320.

[0076] Moreover, if Figure 7 As shown, the ammeter, the DC power supply, the upper end of one of the resistors 310, the conductive member 320 and the upper end of the other resistor 310 are electrically connected in a closed loop to form a first loop. At this time, the ammeter can detect the current value flowing through the two resistors 310; at the same time, the voltmeter, the upper end of one of the resistors 310 and the conductive member 320 and the upper end of the other resistor 310 are electrically connected in a closed loop to form a second loop. At this time, the voltmeter can detect the voltage value between the upper end of one of the resistors 310 and the upper end of the other resistor 310.

[0077] It is understood that this design can reduce the number of wires connected to the conductive element 320, preventing the wires from affecting the linear motion of the conductive element 320 in the vertical direction, thereby improving the accuracy of the thermal elongation test. In this embodiment, the resistance value is equal to the quotient of the voltage value and the current value, and the resistance value is equal to the product of the resistance per unit length of the resistor 310 and the total energized length of the two resistors 310. The total energized length of the two resistors 310 is equal to twice the vertical distance H between the conductive element 320 and the upper end of the resistor 310, which is also equal to twice the length of the cable sample 510. Therefore, when the lower end of the cable sample 510 extends downward a small distance, the total energized length of the two resistors 310 doubles, making the change in the current value more significant. This can achieve a "four-two-pound effect" and facilitate a more accurate calculation of the length L1 of the cable sample 510 during the thermal elongation test.

[0078] In some embodiments, as Figure 4 and Figure 5 As shown, the cable thermal elongation test device further includes a reset adjustment mechanism 400. The reset adjustment mechanism 400 is used to move the load member 220 upward to a position to complete the reset work of the load member 220 and facilitate the connection between the load member 220 and the lower end of the test piece.

[0079] The reset adjustment mechanism 400 includes a first driving member 410 and a lifting member 420. The lifting member 420 is disposed within the heating chamber 111 and is positioned below the load member 220. The output end of the first driving member 410 is connected to the lifting member 420. The first driving member 410 is used to drive the lifting member 420 to move in the vertical direction, so that the lifting member 420 lifts the load member 220 to a set position, allowing the lower end of the test piece to be inserted into the second slot 221 along the first direction.

[0080] It is understandable that the first driving member 410 can be a linear driving device such as a cylinder, an electric cylinder or a linear module. The lifting member 420 has a supporting surface, and the supporting surface can be in contact with the load member 220, so that the lifting member 420 lifts the load member 220 to a set position under the driving action of the first driving member 410. In this embodiment, the first driving member 410 is a servo electric cylinder, and the first driving member 410 is arranged outside the heating chamber 111, and the output end of the first driving member 410 extends into the heating chamber 111 and is fixedly connected to the lifting member 420. The connection between the output end of the first driving member 410 and the wall surface of the heating chamber 111 can be insulated and heat-insulated with a heat-insulating material to prevent heat from being easily lost from the gap between the output end of the first driving member 410 and the heating chamber 111.

[0081] After completing the resetting work of the load member 220, it is convenient to clamp the upper and lower ends of the test piece respectively by the robot arm, and accurately insert the upper and lower ends of the test piece into the first slot 211 of the suspension member 210 and the second slot 221 of the load member 220 along the first direction. Moreover, after completing the thermal elongation test work, the reset adjustment mechanism 400 can be operated to reset the load member 220, and then the upper and lower ends of the test piece can be clamped respectively by the robot arm to remove them from the first slot 211 and the second slot 221 respectively; this can improve the loading and unloading efficiency of the test pieces, avoid high-temperature burns to the test personnel, and facilitate rapid testing of multiple batches of test pieces.

[0082] In some embodiments, the cable thermal elongation testing device further includes a second drive member. The second drive member is used to drive the door 120 to open and close. It is understandable that in some examples, the door 120 is slidably connected to the box body 110, so that the door 120 moves horizontally or moves up and down. The second drive member can be a cylinder, an electric cylinder or a linear module, etc. The second drive member can drive the door 120 to move back and forth horizontally or up and down, thereby controlling the opening of the heating chamber 111 to open and close automatically. In other examples, the door 120 is rotatably connected to the box body 110, and the second drive member can be a motor or a rotary cylinder. The second drive member can drive the door 120 to rotate forward or reverse, thereby controlling the opening of the heating chamber 111 to open or close automatically.

[0083] The control processor is electrically connected to the reset adjustment mechanism 400 and the second driving member through wires, and the control processor can be used to control the second driving member to drive the door 120 to open after the reset adjustment mechanism 400 drives the load member 220 to move up to the set position.

[0084] It is understood that after completing the thermal elongation test, the tester sends a control instruction to the reset adjustment mechanism 400 through the control processor, causing the reset adjustment mechanism 400 to operate, thereby driving the load member 220 and the conductive member 320 to move upward a certain distance, returning the load member 220 to its initial position, and facilitating rapid docking of the load member 220 with the lower end of the test piece. After the reset adjustment mechanism 400 completes its reset operation, the control processor sends a control instruction to the second drive member, causing the second drive member to drive the chamber door 120 to open, allowing the manipulator to quickly remove the completed test piece from the heating chamber 111 and place the next test piece in the heating chamber 111, and quickly connect it to the suspension member 210 and the load member 220, respectively.

[0085] Such a design can improve the degree of automation of the cable thermal elongation testing device, enabling test personnel to focus on the preparation of test pieces, measuring the original length L0 of the cable sample 510, and placing the test pieces one by one on the loading rack, so as to facilitate the use of a robot to place the test pieces on the loading rack one by one in the heating chamber 111 for thermal elongation testing.

[0086] In addition, the robot arm can be electrically connected to the control processor. After the robot arm completes the loading work, the control processor will control the second driving component to operate, allowing the second driving component to drive the box door 120 to automatically close in order to perform the thermal elongation test.

[0087] Further, such as Figure 10As shown, the cable thermal elongation tester also includes a temperature sensor. The temperature sensor is used to collect the real-time temperature within the heating chamber 111. The number of temperature sensors is not limited to one. The installation location of the temperature sensor can be selected based on actual needs and is not specifically limited here. If multiple temperature sensors are installed, they can be placed in different corners of the heating chamber 111. When the real-time temperature data collected by multiple temperature sensors reaches the set temperature, it indicates that the air temperature within the heating chamber 111 is constant, providing a constant temperature testing environment for the cable sample 510.

[0088] Furthermore, the control processor is electrically connected to a timing unit, and the control processor is electrically connected to the temperature sensor. The control processor can also be used to control the timing unit to start timing the test time when the real-time temperature reaches the set temperature, and can collect the current value transmitted by the ammeter and the voltage value transmitted by the voltmeter when the test time reaches the set time.

[0089] Such a design can improve the degree of automation of the cable thermal elongation test device. While automatically monitoring the real-time temperature in the heating chamber 111, the test time is automatically counted. After the test time is over, the current value and voltage meter are immediately collected through the control processor, and then displayed on the display screen 140, which is convenient for the test personnel to observe and record. Moreover, it is also convenient for the test personnel to view the data after the test work. The test personnel do not need to use an additional timer to count and keep an eye on the test time at all times, allowing the test personnel to concentrate more on the preparation of the test pieces.

[0090] Furthermore, if Figure 8 and Figure 11 As shown, the measurement system also includes a control switch. The control switch, ammeter, DC power supply, conductive member 320, and upper end of resistor 310 are electrically connected in a closed loop to form a third circuit. The control switch controls the on / off state of the third circuit. The control switch is electrically connected to a control processor, which is further configured to control the control switch to conduct after the second driver closes door 120.

[0091] With such a configuration, when the control processor controls the second drive member to drive the box door 120 to switch from an open state to a closed state, the test piece is in a closed test space. At this time, the control switch can be controlled to be turned on, so that current flows through the third circuit, allowing the control processor to continuously collect data from the ammeter and voltmeter, making it convenient for the test personnel to view the data status during the test in real time.

[0092] In some embodiments, the heating chamber 111 of the test chamber 100 has only one test station, which can only hold one test piece at a time. In other embodiments, the heating chamber 111 of the test chamber 100 has two or more test stations, which can hold multiple test pieces at a time, so as to obtain the final result of the thermal elongation of the cable sample 510 by taking an average value. In this case, multiple suspension members 210, load members 220, guide rods 230, and measurement systems are provided. When a reset adjustment mechanism 400 is provided, all load members 220 can be driven upward by the same reset adjustment mechanism 400 to complete the reset of the load members 220.

[0093] like Figures 1 to 12 As shown, the control method of the cable thermal elongation test device according to the second embodiment of the present invention is applied to the cable thermal elongation test device according to the first embodiment, and the control method of the cable thermal elongation test device includes the following steps:

[0094] Step S11: When the test piece is connected to the suspension piece 210 and the load piece 220 respectively and the temperature of the heating chamber 111 reaches the set temperature, the timing unit is controlled to start timing the test time.

[0095] Step S12: When the test time reaches the set time, the current current value of the ammeter and the current voltage value of the voltmeter are collected.

[0096] Step S13 : calculating the energized length of the resistor 310 according to the current current value, the current voltage value, and the resistance per unit length of the resistor 310 .

[0097] Step S14 : controlling the display screen 140 to display the length value of the cable sample 510 .

[0098] After the test piece is installed in the test box 100, the test box 100 is closed and the temperature is increased so that the temperature in the heating chamber 111 can reach the set temperature for the thermal extension test; when the temperature in the heating chamber 111 reaches the requirement, the test time can be counted by the timing unit, so that the test piece can undergo a thermal extension test under the action of high temperature and mechanical load; when the test time accumulates to the set time, the control processor can collect the current current value detected by the ammeter and the current voltage value detected by the voltmeter, and quickly calculate the energized length of the resistor 310 based on the current current value, the current voltage value and the known unit length resistance value of the resistor 310.

[0099] Since the upper and lower distance H between the conductive member 320 and the upper end of the resistor 310 is designed to be equal to the length value of the cable sample 510, and the energized length of the resistor 310 is equal to the upper and lower distance between the conductive member 320 and the upper end of the resistor 310, the energized length of the resistor 310 calculated by the control processor is the length value of the cable sample 510; finally, the control processor controls the display screen 140 to operate, and clearly displays the length value of the cable sample 510 after extension during the thermal extension test through the display screen 140, so that the test personnel can accurately calculate the thermal extension rate of the cable based on the previously measured original length of the cable sample 510 and the length value of the cable sample 510 during the thermal extension test.

[0100] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0101] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A cable thermal elongation test device, characterized in that: include: The test box is provided with a heating chamber and a display screen, wherein a guide rod extending in an up-down direction is provided in the heating chamber; a hanging member fixedly disposed in the heating chamber for detachably connecting to the upper end of a test piece, wherein the test piece includes a cable sample and two clamping members fixed to the upper and lower ends of the cable sample; a load member, slidably connected to the guide rod up and down, and disposed directly below the suspension member, for detachably connecting to the lower end of the test piece; A measurement system comprising a resistor, a conductive member, a DC power supply, an ammeter, and a voltmeter, wherein the resistor extends in a vertical direction and is fixedly disposed within the heating chamber, the conductive member being connected to the load member and in sliding contact with the outer circumference of the resistor and conducting electricity, such that a vertical distance between the conductive member and the upper end of the resistor is equal to the length of the cable sample, the ammeter, the DC power supply, the conductive member, and the upper end of the resistor being electrically connected in a closed loop so that the ammeter can collect current values, and the voltmeter, the conductive member, and the upper end of the resistor being electrically connected in a closed loop so that the voltmeter can collect voltage values; a control processor electrically connected to the ammeter, the voltmeter, and the display screen, and configured to calculate the energized length of the resistor according to the current value, the voltage value, and the resistance per unit length of the resistor, and control the display screen to display the length value of the cable sample, wherein the energized length of the resistor is the vertical distance between the conductive member and the upper end of the resistor; The resistor is cylindrical, two resistors are provided and spaced apart in the horizontal direction, the conductive member is provided with two contacts, the conductive member is located between the two resistors so that the two contacts are in sliding contact with the outer circumferences of the two resistors and conduct electricity, the ammeter, the DC power supply, the upper end of one of the resistors, the conductive member and the upper end of the other resistor are electrically connected in a closed loop to form a first loop, and the voltmeter, the upper end of one of the resistors, the conductive member and the upper end of the other resistor are electrically connected in a closed loop to form a second loop; the guide rod is a round rod, and at least one is provided, and the load member is provided with a guide sleeve slidably connected to the guide rod; The test chamber includes a chamber body and a chamber door, wherein the chamber door is located on one side of the chamber body along a first direction and is movably connected to the chamber body to open and close the opening of the heating chamber, a first slot is provided at the lower end of the suspension member for inserting the upper end of the test piece along the first direction, and a second slot is provided at the upper end of the load member for inserting the lower end of the test piece along the first direction, wherein the first direction is perpendicular to the up-down direction; The cable thermal elongation testing device also includes a reset adjustment mechanism, which includes a first driving member and a lifting member. The lifting member is arranged in the heating chamber and is located below the load member. The first driving member is used to drive the lifting member to move in the up and down directions so that the lifting member lifts the load member to a set position, so that the lower end of the test piece can be inserted into the second slot along the first direction.

2. The cable thermal elongation tester according to claim 1, characterized in that: The cross-section of the first card slot is T-shaped, and the cross-section of the second card slot is inverted T-shaped.

3. The cable thermal elongation testing device according to claim 1, characterized in that: The first driving member is a servo electric cylinder and is arranged outside the heating chamber. The output end of the first driving member extends into the heating chamber and is fixedly connected to the lifting member.

4. The cable thermal elongation tester according to claim 1, characterized in that: It also includes a second driving member, which is used to drive the box door to open and close. The control processor is electrically connected to the reset adjustment mechanism and the second driving member respectively, and is used to control the second driving member to drive the box door to open after the reset adjustment mechanism drives the load member to move up to the set position.

5. The cable thermal elongation tester according to claim 4, characterized in that: It also includes a temperature sensor, which is used to collect the real-time temperature in the heating chamber. The control processor is electrically connected to a timing unit, and the control processor is electrically connected to the temperature sensor. The control processor is used to control the timing unit to time the test time when the real-time temperature reaches the set temperature, and collect the current value and the voltage value when the test time reaches the set time.

6. The cable thermal elongation tester according to claim 5, characterized in that: The measurement system also includes a control switch, wherein the control switch, the ammeter, the DC power supply, the conductive member, and the upper end of the resistive member are electrically connected in a closed loop, and the control switch is electrically connected to the control processor. The control processor is used to control the control switch to be turned on after the second driving member drives the box door to close.

7. A control method for a cable thermal elongation test device, applied to the cable thermal elongation test device according to claim 5 or 6, characterized in that: The steps include: When the test piece is connected to the suspension piece and the load piece respectively and the temperature of the heating chamber reaches a set temperature, controlling the timing unit to operate to count the test time; When the test time reaches the set time, the current current value of the ammeter and the current voltage value of the voltmeter are collected; Calculating the energized length of the resistor according to the current current value, the current voltage value, and the resistance per unit length of the resistor; The display screen is controlled to display the length value of the cable sample.

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