Apparatus of measuring an erosion degree of a female pin of a charging connector for an electric vehicle

Abstract

A wear measuring device for an electric vehicle charging connector female pin, for measuring the wear of an inner surface defining an insertion groove formed in a female pin of a charging connector, comprises: a male pin body having a first electrode that can be electrically connected to the female pin and configured to be inserted into the insertion groove, and a recess area formed on its outer periphery; a second electrode configured to surround the recess area and configured to be spaced apart from the inner surface of the connector female pin; and a capacitance measuring unit that measures a capacitance value that changes according to a change in the surface roughness value of the inner surface between the first electrode and the second electrode.

Description

Technology Field

[0001] Embodiments of the present invention relate to a wear measuring device for a female pin of a charging connector for an electric vehicle. More specifically, embodiments of the present invention relate to a wear measuring device for an internal surface of a female pin of a charging connector for an electric vehicle capable of measuring the wear of an internal surface defining an insertion groove that constitutes a female pin formed at one end of a charging cable for charging a battery included in an electric vehicle. Background Technology

[0002] As the adoption of electric vehicles expands, charging infrastructure is rapidly being expanded. Accordingly, charging connectors are being used to interconnect the battery and power source in order to charge the battery of the electric vehicle. The charging connector experiences wear and tear during the repeated insertion and removal process, and such wear can lead to reduced charging efficiency and safety issues.

[0003] The above-mentioned charging connector is connected to the male pin of a charging socket that supplies power and is installed on a wall or pillar. In this case, the charging connector is in the form of a hollow female pin, and when not in use, this female pin connector is fitted into a blank or stand to maintain it in a form that can block moisture or dust to some extent.

[0004] To check the amount of wear on the female pin formed in the charging connector, visual inspection or physical quantity measurement methods were mainly used. However, these methods had problems such as requiring the charging connector to be disassembled or having low measurement accuracy. In addition, there is a limitation in that real-time monitoring is impossible, making preventive maintenance difficult. In particular, it is difficult to measure the wear of various charging connectors used in various environments using a single measuring device. The problem to be solved

[0005] Embodiments of the present invention provide a wear measuring device for an electric vehicle charging connector female pin capable of precisely measuring the wear of an electric vehicle charging connector. means of solving the problem

[0006] A wear measuring device for an electric vehicle charging connector female pin, for measuring the wear of an inner surface defining an insertion groove formed in a female pin of a charging connector according to embodiments of the present invention for solving the above technical problem, comprises: a male pin body having a first electrode that can be electrically connected to the female pin and is configured to be inserted into the insertion groove, and a recess area formed on the outer periphery; a second electrode formed to surround the recess area and configured to be spaced apart from the inner surface of the connector female pin; and a capacitance measuring unit that measures a capacitance value that changes according to a change in the surface roughness value of the inner surface between the first electrode and the second electrode.

[0007] In one embodiment of the present invention, the second electrode may be provided to maintain a shortest separation distance from the inner surface of the connector female pin at a constant level regardless of the degree of wear of the inner surface.

[0008] In one embodiment of the present invention, the female pin may include a charging electrode having a cylindrical shape that defines the insertion groove.

[0009] Here, the first electrode may include an electrode head portion that contacts one end of the charging electrode and an electrode extension portion that extends from the electrode head portion to penetrate the center of the pin body.

[0010] In addition, the first electrode may include a material having a lower hardness than the charging electrode.

[0011] In one embodiment of the present invention, the second electrode may have a ring shape.

[0012] In one embodiment of the present invention, a calculation unit for estimating a change in surface roughness of the inner surface from a change in capacitance, a storage unit for storing data regarding a change in capacitance and a change in surface roughness, and a determination unit for determining a replacement part of the charging connector from a change in surface roughness may be additionally provided. Effects of the invention

[0013] According to the embodiments of the present invention described above, the degree of wear on the inner surface defining the insertion groove of the female pin of the charging cable can be non-destructively verified by measuring the capacitance between the first electrode and the second electrode, which changes according to the degree of wear on the inner surface. In particular, by tracking the change in capacitance value according to the change in wear while maintaining a constant minimum separation distance between the inner surfaces of the charging electrodes and the second electrode is connected to the first electrode in an annular manner, the history of past charging and the replacement time of the charging cable due to wear can be predicted. Brief explanation of the drawing

[0014] Figure 1 is a photograph of an electric vehicle charging cable. FIG. 2 is a drawing showing the state in which a wear measuring device according to embodiments of the present invention is separated from the receiving groove of a female pin of an electric vehicle charging cable. Figure 3 is a cross-sectional view illustrating the wear measuring device of Figure 2. FIG. 4 is a block diagram illustrating a wear measuring device according to embodiments of the present invention. Figure 5 is a graph showing the change in capacitance according to the change in surface roughness using the wear measuring device of Figure 2. Specific details for implementing the invention

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. As the present invention is susceptible to various modifications and may take various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention. Similar reference numerals have been used for similar components in the description of each drawing. In the attached drawings, the dimensions of the structures are shown enlarged compared to the actual dimensions for the clarity of the present invention.

[0016] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component.

[0017] The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0018] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0019] FIG. 1 is a photograph of an electric vehicle charging cable. FIG. 2 is a diagram showing a state in which a wear measuring device according to embodiments of the present invention is separated from the receiving groove of a female pin of an electric vehicle charging cable. FIG. 3 is a cross-sectional view showing the wear measuring device of FIG. 2. FIG. 4 is a block diagram showing a wear measuring device according to embodiments of the present invention.

[0020] Referring to FIGS. 1 to 4, a wear measuring device (100) according to embodiments of the present invention includes a male pin body (110) having a first electrode (111), a second electrode (120), and a capacitance measuring unit (150). Each component is electrically connected to perform the function of accurately measuring and analyzing the wear of the inner surface of a female pin (11) of a charging connector (10).

[0021] Referring to FIGS. 1 and 2, the electric vehicle charging cable (10) includes a plurality of female pins (11). Each of the female pins (11) includes an insertion groove (15) provided so that a male pin of a charging socket can be inserted.

[0022] Wear may occur on the inner surface defining the insertion groove (15) as the charging cable (10) is used for a long time. In particular, if the wear occurs excessively, the bonding force between the charging cable (10) and the socket (not shown) may be weakened, causing errors in charging. The charging electrode formed by the inner surface may have a cylindrical shape. The charging electrode may define the insertion groove (15). The charging electrode corresponds to a component of the charging cable (10) that supplies power to the battery of an electric vehicle through the socket.

[0023] Referring again to FIGS. 1 to 4, the male pin body (110) may be provided to be internally fastened into the insertion groove (15) of the female pin (11). That is, the male pin body (110) may have a shape and size corresponding to the insertion groove (15). For example, if the insertion groove (15) has a cylindrical shape, the male pin body (110) may have a cylindrical shape. In addition, if the insertion groove (15) has a first diameter, the male pin body (110) may have substantially the same first diameter so as to be inserted into the insertion groove.

[0024] The male pin body (110) is precisely designed so that it can be accurately inserted into the female pin (11) insertion groove (15) of the charging connector (10). For example, the total length of the male pin body (110) is 50±0.5mm, and the outer diameter is 8±0.1mm. These dimensions are designed to match the specifications of the standard charging connector (10).

[0025] Meanwhile, a recess area (115) is formed on the outer periphery of the pin body (110). The depth of the recess area may be 1.5 ± 0.05 mm. Additionally, the length of the recess area (115) is machined to be 30 ± 0.3 mm. Since the machining precision of the recess area directly affects the accuracy of the measurement, machining using a CNC precision lathe is essential.

[0026] Additionally, the male pin body (110) may be made of a material having mechanical durability and electrical insulation.

[0027] The first electrode (111) is provided to be electrically connected to the female pin (11). The first electrode (111) may be connected, for example, to the charging electrode of the female pin (11). Thus, the first electrode (111) may have substantially the same potential as the charging electrode.

[0028] The second electrode (120) is positioned to surround the recess area (115). The second electrode (120) may have a thickness smaller than the depth of the recess area (115). Thus, the second electrode (120) may have an upper surface lower than the upper surface of the male pin body (110). Thus, when the wear measuring device (100) is inserted into the insertion groove (115) of the female pin (11), the second electrode (120) may be spaced apart from the inner surface defining the insertion groove, i.e., the charging electrode. The shortest separation distance at this time is defined as d in FIG. 3. For example, the shortest separation distance may be in the range of 0.5 ± 0.02 mm. To maintain a stable shortest separation distance, a three-point support type insulating spacer (not shown) may be used. That is, a floating mount structure to compensate for the effects of thermal expansion may be applied.

[0029] A charging capacity measuring unit (150, see FIG. 4) measures the capacitance between the first electrode (111) and the second electrode (120). The first electrode (111), which is in ohmic contact with the charging electrode, has the same potential as the charging electrode, and the second electrode (120) has a constant counter potential. Additionally, the separation distance between the first and second electrodes (111, 120) defining the capacitance has a constant d value (see FIG. 3).

[0030] At this time, the effective area of ​​the capacitance may change depending on the surface roughness of the inner surface defining the insertion groove (15), that is, the charging electrode. That is, as the surface roughness increases due to wear on the inner surface forming the charging electrode, the effective area of ​​the capacitance may increase. Accordingly, the capacitance values ​​of the first and second electrodes (111, 120) may increase.

[0031] Figure 5 is a graph showing the change in capacitance according to the change in surface roughness using the wear measuring device of Figure 2.

[0032] Referring to FIG. 5, the wear measuring device (100) according to embodiments of the present invention can track the amount of change in the capacitance by measuring the capacitance. Thus, when the capacitance exceeds a threshold value, it can be seen that the female pin (11) of the charging connector (10) is significantly worn and requires replacement of the charging connector (10).

[0033] In one embodiment of the present invention, the first electrode (111) may include an electrode head portion (112) and an electrode extension portion (113).

[0034] The electrode head portion (112) can make contact with one end of the charging electrode. Since the electrode head portion (112) has a dome shape, it can make more solid and stable contact with the charging electrode.

[0035] The electrode extension portion (113) may be extended from the electrode head portion (111) to penetrate the center of the pin body (110). The electrode extension portion (113) may make the charging electrode and one electrode of the capacitance measuring portion (150), which are electrically connected to the electrode head portion (112), mutually equal potential, i.e., equipotential.

[0036] Meanwhile, the first electrode (111) may have a lower hardness than the charging electrode. When the first electrode (111) comes into contact with the charging electrode, damage to the charging electrode can be suppressed. In particular, the first electrode (111) may have a hardness of HV 150 to 180. For example, the electrode head portion (111) may be made of brass.

[0037] The second electrode (120) has a ring shape and can be manufactured with precise dimensions of an inner diameter of 7.1±0.05mm, an outer diameter of 8±0.05mm, and a thickness of 0.5±0.05mm. The material used is beryllium copper (C17200), and the surface is gold-plated with a thickness of 1μm.

[0038] The capacitance measuring unit (150) is connected to the first and second electrodes (111, 120). The capacitance measuring unit (150) can measure a capacitance value that changes according to a change in the surface roughness value of the inner surface between the first electrode (111) and the second electrode (120).

[0039] The above capacitance measuring unit (150) may include a sinusoidal oscillator, a phase detector, an AD converter, and an amplifier.

[0040] A wear measurement device (100) according to embodiments of the present invention may further include a calculation unit (160), a storage unit (170), and a judgment unit (180).

[0041] The calculation unit (160) can estimate the change in surface roughness of the inner surface from the change in capacitance. The calculation unit (160) is equipped with an ARM Cortex-M4F processor and operates at a clock speed of 168 MHz. It is equipped with 1 MB of Flash memory and 192 KB of RAM, enabling complex computation processing. It supports communication with external devices via USB and Bluetooth 5.0 interfaces. The calculation unit (160) converts the measured capacitance value into a surface roughness value. The roughness conversion algorithm is based on the following formula.

[0042] Ra = k1(Cx / C0 - 1) + k2

[0043] Here, Ra represents the surface roughness value, k1 and k2 are calibration constants, Cx represents the measured capacitance value, and C0 represents the reference capacitance value. The conversion algorithm includes corrections based on environmental conditions such as temperature (-20°C to 60°C), humidity (20 to 80 %RH), and atmospheric pressure (850 to 1,050 hPa).

[0044] The storage unit (170) stores data including measurement time and date, raw capacitance data, calculated roughness values, environmental conditions, system status information, etc. For the safe storage of data, it provides functions such as automatic backup at a 24-hour period, manual backup, cloud synchronization when connected to WiFi, and AES-256 encryption.

[0045] The judgment unit (180) can determine the timing for replacing the charging connector based on the measured data.

[0046] For example, a measured roughness value can be determined to be at a warning level when increasing by 50% compared to the initial roughness, replacement is required when increasing by 100%, and emergency replacement when increasing by 150%. This determination is based on algorithms such as wear rate calculation and life prediction through linear regression analysis, detection of abnormal wear patterns, and detection of sudden changes.

[0047] Alternatively, the replacement timing can be determined based on the rate of change in capacitance over time. That is, if the rate of change in capacitance during a specific inspection period is lower than the reference value, it means that wear is not progressing. This implies that the male pin body is separated from the female pin of the charging connector, thereby preventing effective contact of the charging connector. Therefore, if the rate of change in capacitance over time is smaller than the reference value, information for replacement can be provided.

[0048] The actual measurement proceeds according to the following procedure. First, preparation steps are performed, including self-diagnosis of the wear measuring device, sensor zero adjustment, and checking the remaining battery level. After checking the temperature, humidity, and EMI levels of the measurement environment, the wear measuring device is inserted into the insertion groove formed in the female pin to start the measurement. When inserting the probe, the alignment, insertion depth, and contact status must be carefully checked. After a stabilization period of 3 seconds, 10 consecutive measurements are performed to calculate the average value.

[0049] Regular maintenance and replacement are essential to maintain equipment reliability. Calibration using standard specimens is performed every six months, and calibration certificates are issued and history is managed. Routinely, the cleanliness of probes, the wear condition of electrodes, the condition of cables, and battery status must be checked. Troubleshooting procedures are also in place to handle issues such as measurement instability, communication errors, battery problems, and system freezes.

[0050] Meanwhile, various noise reduction technologies have been applied to improve the accuracy of capacitance measurements. The triple-shield structure blocks external electromagnetic interference, and the multi-point grounding method minimizes noise caused by ground loops. The μ-metal shield blocks low-frequency magnetic field interference. The moving average filter is effective in reducing unnecessary fluctuations in measurement values.

[0051] The measuring device of the present invention is designed to operate stably under various environmental conditions. Normal measurements are possible in a temperature range from -20°C to 60°C and in an environment with relative humidity from 20% to 80%. To this end, a correction algorithm based on temperature, humidity, and atmospheric pressure is applied, and these environmental variables are stored together with the measurement data and used for future analysis.

[0052] Meanwhile, both security and reliability were considered in terms of data management. Data confidentiality is guaranteed through AES-256 encryption, and secure data storage is ensured through automatic backup and cloud synchronization. Measurement data is stored in a format suitable for time-series analysis, which is utilized to identify wear trends and predict lifespan.

[0053] The roughness value, which serves as the standard for assessing wear, is determined by comparing it to the initial state. It is divided into three levels: Warning (50% increase), Replacement Required (100% increase), and Emergency Replacement (150% increase), with appropriate measures recommended for each stage. These standard values ​​were established through long-term data analysis in actual usage environments and can be adjusted as necessary.

[0054] Monitoring the progression of wear utilizes advanced analytical techniques that go beyond simple threshold comparisons. It calculates the wear rate through linear regression analysis and predicts the remaining lifespan based on this. Furthermore, it provides separate warnings if rapid wear changes or abnormal patterns are detected, enabling the identification of problems in advance.

[0055] The wear measurement device according to the embodiments of the present invention is expected to significantly contribute to improving the safety and reliability of electric vehicle charging infrastructure. The condition of the connector can be accurately diagnosed through a non-destructive inspection method, and safety accidents can be prevented through preventive maintenance. Furthermore, the accumulation of measurement data enables the prediction of the connector's lifespan and the optimization of its replacement cycle, thereby allowing for the expectation of reduced maintenance costs.

Claims

Claim 1 A wear measuring device for an electric vehicle charging connector female pin, for measuring the wear of an inner surface defining an insertion groove formed in a female pin of a charging connector, comprising: a male pin body having a first electrode that can be inserted into the insertion groove and can be electrically connected to the female pin, and a recess area formed on the outer periphery; a second electrode formed to surround the recess area and spaced apart from the inner surface of the connector female pin; and a capacitance measuring unit that measures a capacitance value that changes according to a change in the surface roughness value of the inner surface between the first and second electrodes. Claim 2 A wear measuring device for a charging connector female pin of an electric vehicle, characterized in that, in claim 1, the second electrode is provided to maintain a constant minimum separation distance from the inner surface of the connector female pin regardless of the wear of the inner surface. Claim 3 A wear measuring device for a charging connector female pin for an electric vehicle, characterized in that, in claim 1, the female pin includes a charging electrode having a cylindrical shape defining the insertion groove. Claim 4 A wear measuring device for a female pin of a charging connector for an electric vehicle, characterized in that, in paragraph 3, the first electrode comprises: an electrode head portion that contacts one end of the charging electrode; and an electrode extension portion that extends from the electrode head portion to penetrate the center of the male pin body. Claim 5 A wear measuring device for an automotive charging connector female pin, characterized in that, in paragraph 3, the first electrode comprises a material having a lower hardness than the charging electrode. Claim 6 A wear measuring device for a charging connector female pin for an electric vehicle, characterized in that, in claim 1, the second electrode has a ring shape. Claim 7 A wear measuring device for a charging connector female pin of an electric vehicle, characterized in that, in claim 1, it further comprises: a calculation unit for estimating a change in surface roughness of the inner surface from a change in capacitance; a storage unit for storing data regarding the change in capacitance and the change in surface roughness; and a judgment unit for determining a replacement part of the charging connector from the change in surface roughness.

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