A harness piercing crimping quality detection method based on resistance measurement

Abstract

This invention relates to a method for detecting wire harness puncture and crimping quality based on resistance measurement. First, X-ray imaging is used to select samples of various defects and qualified products. The resistance values ​​of these samples are measured to establish a correspondence between resistance values ​​and defects, which is then used by a computer for judgment during subsequent product testing. Next, a resistance detection system is used to test the resistance of a group of wire harnesses, obtaining the parallel resistance values ​​of multiple wires. Using Ohm's law and the series-parallel relationship of resistances, the resistance value of a single wire in the product under test can be obtained. This value is then compared with a comparison threshold set in the computer to quickly determine whether the product under test is qualified or its defect type. A robotic arm then removes and discards unqualified products. Compared to existing X-ray imaging methods, this method significantly improves detection efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the quality detection of piercing crimping terminals, and particularly relates to a crimping quality detection method for wire harness piercing terminals based on resistance measurement. BACKGROUND

[0002] As the "nerves" of the automobile, the wire harness is an indispensable component in the automobile electrical appliances, and the reliability of the wire connection is crucial. The wire harness and the connecting terminal are usually connected by a crimping machine, and the piercing terminal crimping machine is a widely used device at present. The piercing terminal crimping machine connects the connecting terminal and the wire harness by extruding the connecting terminal to make the piercing in the connecting terminal penetrate the insulating skin of the wire and connect with the copper wire inside the terminal. However, during the crimping process, due to improper operation, quality problems such as the connecting terminal being cracked, the wire core being broken, and the connecting terminal and the wire not having enough holding force may occur. The unqualified products generated thereby need to be removed, and therefore, it is necessary to detect the crimping quality of the wire harness.

[0003] The existing detection method for the crimping quality of the wire harness mainly uses X-ray inspection to determine whether the crimping state of the product to be detected meets the standard by observing the product to be detected through an industrial X-ray machine. However, this method has low detection efficiency and can only detect a single wire, which is not suitable for a large number of automobile wire harnesses. SUMMARY

[0004] The present application discloses a crimping quality detection method for wire harness piercing terminals based on resistance measurement. The resistance value of the wire harness after crimping is detected to determine the crimping quality. The resistance value of the wire harness with good crimping quality is small, and the resistance value of the unqualified product is large. Therefore, the resistance value of the qualified product can be determined to measure the resistance of the crimped wire harness by using the resistance detection system of the present application to screen out the unqualified products.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A crimping quality detection method for wire harness piercing terminals based on resistance measurement, comprising the following contents:

[0007] Step 1: Use the X-ray machine inspection method to select a plurality of qualified products and a plurality of unqualified products from a plurality of wire harness piercing terminal products;

[0008] Step 2: Measure the resistance values of the selected qualified products and unqualified products by using a multimeter, and set a comparison threshold for determining the resistance value of the product to be detected in the computer according to the distribution of the resistance value of the single wire of the qualified product;

[0009] Step 3: Prepare the product to be tested. The product to be tested is a wire harness piercing crimp terminal. The wire harness piercing crimp terminal includes a wire harness and a wire harness terminal. The wires inside the wire harness terminal are multiple and arranged in the same direction. The socket on the wire harness terminal is provided with a connecting spring corresponding to each wire.

[0010] Step 4: Set up a resistance value detection system. The resistance value detection system includes a metal detection probe, a constant voltage source, a data acquisition card, a robotic arm, and a computer. The two ends of the metal detection probe are connected to a hollow bracket. The hollow bracket has internal wiring, and the metal detection probe is connected to the internal wires of the hollow bracket. The other end of the internal wires of the hollow bracket is connected to the constant voltage source, the data acquisition card, and the computer.

[0011] Step 5: The robotic arm includes a first robotic arm and a second robotic arm, both of which are controlled by a computer. The first robotic arm is used to hold the wire harness terminal, and the second robotic arm is used to hold the hollow bracket. The computer controls the second robotic arm to insert the metal detection probe into the socket on the wire harness terminal, so that the metal detection probe makes contact with the connecting spring corresponding to each wire at the same time.

[0012] Step 6: After completing Step 5, turn on the constant voltage source, collect the current value of the circuit through the data acquisition card and feed it back to the computer. The computer calculates the resistance value of each wire inside the wire harness terminal, compares the calculated resistance value of a single wire with the comparison threshold set in the computer. If the resistance value is greater than the comparison threshold, it is a defective product. The second robotic arm places the defective product in the defective storage area.

[0013] Furthermore, in step 1, the selected non-conforming products include at least two defects: improper wire harness insertion and missing wire harness. In step 2, the average resistance value of the individual wires of multiple qualified products is calculated, and this average resistance value is determined as the comparison threshold. At the same time, the resistance values ​​of the individual wires of multiple non-conforming products corresponding to the two defects are calculated, and the corresponding average resistance values ​​are calculated. The average resistance values ​​of the corresponding defect types are entered into the computer to determine the defect type of the detected non-conforming products.

[0014] Furthermore, in step 3, a wire through hole is opened on the wire harness terminal, the wire enters the wire harness terminal through the wire through hole and is electrically connected to the connecting spring, a piercing is provided inside the wire harness terminal, a terminal groove is opened on the outer shell of the wire harness terminal, the lower part of the connecting spring is a rectangular frame, the lower part of the rectangular frame is the piercing, the piercing is fixed by the rectangular frame and the terminal groove, and the piercing is directly opposite the wire through hole.

[0015] Furthermore, in step 4, the hollow support is made of plastic.

[0016] Furthermore, in step 4, the metal detection probe is made of copper.

[0017] Furthermore, in step 4, the metal detection probe is a cylinder.

[0018] This invention relates to a method for detecting wire harness puncture and crimping quality based on resistance measurement. It uses X-ray imaging to select samples of various defects and qualified products, measures the resistance values ​​of these samples, and establishes a correlation between resistance values ​​and defects. This correlation is then used by a computer for judgment during subsequent product testing. This invention utilizes a resistance detection system to calculate the parallel resistance of a set of wire harnesses. Through Ohm's law and the series-parallel relationship of resistances, the resistance value of a single wire in the product under test can be obtained. By comparing this value with a preset comparison threshold in the computer, the quality of the product under test or its defect type can be quickly determined. A robotic arm then removes and discards defective products. Compared to existing X-ray imaging methods, this significantly improves detection efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a metal detection probe being inserted into a wire harness terminal during resistance testing.

[0020] Figure 2 This is a schematic diagram of the wire harness terminal structure;

[0021] Figure 3 A schematic diagram of the wire harness terminal from another perspective;

[0022] Figure 4 This is a schematic diagram of the internal insertion structure of the wire harness terminal;

[0023] Figure 5 This is a schematic diagram of the structure of a metal detection probe.

[0024] Explanation of icon numbers:

[0025] 1. Wire harness terminal; 2. Metal detection probe; 3. Terminal housing; 4. Connecting spring; 5. Insertion bar; 6. Wire through hole; 7. Terminal groove; 8. Rectangular frame; 9. Hollow bracket. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0027] This embodiment discloses a method for detecting the quality of wire harness puncture crimping based on resistance measurement. The crimping quality to be detected here refers to the wire harness puncture crimping terminal. First, the structure of the wire harness puncture crimping terminal is described, as follows: Figures 2 to 4As shown, it mainly includes a set of wire harnesses and wire harness terminals 1. The wire harnesses are omitted in the attached figure. The wire harness terminals include terminal housings 3. One side of the terminal housing 3 has a wire through hole 6, and the other side of the terminal housing 3 has a socket with a metal connecting spring 4. The terminal housing 3 has a piercing bar 5 inside for piercing the outer insulation layer of the wire. The piercing bar 5 is as follows: Figure 4 As shown, the piercing 5 has a forked structure. The hollowed-out area in the middle of the fork is for the wire to pass through. Symmetrical protrusions are arranged on the opposite sidewalls of the fork. The piercing 5 is located precisely at the wire through-hole 6. When the wire is inserted into the wire harness terminal 1 through the wire through-hole 6, the wire is squeezed by the protrusions on the fork of the piercing 5, causing the insulation to be pierced, thus achieving the crimping requirement. The piercing 5 is connected to the connecting spring 4 via a metal rectangular frame 8. The piercing 5 is fixed by the rectangular frame 8 and the terminal groove 7, achieving the requirement of fixing the piercing 5.

[0028] Since there are many wires in the crimp terminals of automotive wiring harnesses, this embodiment and the accompanying drawings only show an example of setting 3 wires in each wiring harness terminal. The 3 wires are arranged in the same direction, which facilitates testing. When testing the resistance value of the wiring harness, the resistance value of multiple wires can be tested at the same time, thus improving the testing efficiency.

[0029] Combination Figure 1 and Figure 5 As shown, the method for detecting the crimping quality of wire harnesses piercing crimp terminals based on the above-described structure is explained below:

[0030] Step 1: First, determine the resistance distribution of the conductors in the qualified and unqualified products of the wire harness piercing the crimp terminal, so as to determine the comparison threshold.

[0031] Specifically, to accurately obtain precise resistance values, this embodiment selects 10 qualified products and 10 unqualified products for each type of defect; the more products selected, the more accurate the calculated data. Simultaneously, to determine the defect type of unqualified products during the inspection process, this embodiment categorizes unqualified products into two defect types: defect type one is improper wire harness insertion, and defect type two is missing wire harness. When selecting these samples, an industrial X-ray machine is used to photograph and select from a large number of products, choosing those that meet the respective requirements.

[0032] Step 2: Use a multimeter to measure the resistance value of the selected sample wires, establish the numerical relationship between the wire harness terminal resistance and the defects, and determine the comparison threshold for judging the resistance value of the product to be tested based on the resistance value of a single wire of a qualified product.

[0033] Specifically, the resistance value of each sample of each type is measured using a multimeter, and the average resistance of each individual wire for each type is calculated to obtain more accurate test results. For example, the resistances R1, R2…R of 10 wires from a qualified product are tested to obtain their values. 10 The average resistance value of the qualified product is calculated to be R. S1 Similarly, tests were performed on 10 wires for defect type one and defect type two respectively, and the average resistance value R for defect type one was calculated. S2 And the average resistance value R of defect type two S3 The average resistance value mentioned above can be used as a comparison threshold for subsequent detection. For example, if the detected resistance value is less than R... S1 Products with a resistance value between R can be considered to have acceptable crimping quality. S1 ~R S2 Products falling between these ranges can be classified as defective products of type one, specifically those with a resistance value greater than R. S3 Products meeting these criteria can be classified as defective products of type two. The aforementioned ranges of average resistance values ​​are input into the computer system for use as comparison values ​​in subsequent testing processes to determine the quality of the tested products.

[0034] Step 3: Set up a resistance value detection system. The resistance value detection system includes, for example: Figure 5 The system includes a metal detection probe 2, a constant voltage source, an ammeter, a data acquisition card, a robotic arm, and a computer. The computer acts as the control mechanism, issuing detection commands and controlling the movement of the robotic arm. The data acquisition card collects the current values ​​in the test circuit and feeds them back to the computer for calculating the resistance values.

[0035] Specifically, in this embodiment, the metal detection probe 2 is a copper cylinder. Copper has high conductivity, and the cylindrical surface is smooth. When the metal detection probe 2 is inserted into the socket of the wire harness terminal 1 and contacts the connecting spring 4, the smooth arc-shaped contact surface will not damage the piercing spring inside the wire harness terminal, achieving lossless contact testing. Hollow brackets 9 are provided at both ends of the metal detection probe 2 to fix it. In this embodiment, the hollow brackets 9 are made of plastic, which can effectively prevent current crosstalk. The hollow interior of the hollow brackets 9 is used for wire routing. The metal detection probe 2 is connected to the wires inside the hollow brackets 9, and the other end of the wires inside the hollow brackets 9 is connected to a constant voltage source, a data acquisition card, and a computer.

[0036] Step 4: Start the resistance value detection system to test the resistance value of the product to be tested.

[0037] In essence, the robotic arm consists of a first robotic arm and a second robotic arm. The computer-controlled first robotic arm holds the wire harness terminal 1 to be tested, while the computer-controlled second robotic arm holds the hollow support 9. The second robotic arm inserts the metal detection probe 2 into the socket on the wire harness terminal 1, ensuring that the metal detection probe 2 simultaneously contacts the corresponding connecting springs 4 of all the wires on the wire harness terminal 1. The inserted metal detection probe 2 presses against the connecting springs 4, causing them to expand slightly to ensure good contact with the metal detection probe 2. After the metal detection probe 2 is fully inserted, a constant voltage source is turned on to sample the circuit current. Using Ohm's law, the parallel resistance of multiple wires can be calculated. Then, using the parallel resistance calculation formula, the resistance of each individual wire can be calculated. This testing method can complete the inspection of the crimping quality of multiple wires in each test, which is far more efficient than traditional X-ray inspection methods.

[0038] Step 5: Determine the quality of the product to be tested.

[0039] After performing step 4, the calculated resistance value of each wire is compared with the comparison threshold set in the computer to determine which quality category the resistance value falls into. For resistance values ​​less than R... S1 Products that meet the specified crimping quality standards will be placed in the qualified product area by the second robotic arm; for products with a resistance value between R... S1 ~R S2 Products falling between these categories can be classified as defective products of type one, and the second robotic arm will place these defective products into the corresponding non-conforming product area; for products with a resistance value greater than R... S3 Products that meet the criteria can be identified as defective products of type two. The second robotic arm will then place these defective products into the corresponding non-conforming product area. This method not only efficiently and quickly determines the crimping quality of the products under inspection, but also allows the robotic arm to classify the tested products. The computer records all test results, which can be viewed and analyzed by technicians, providing a data source for improving product crimping quality.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for detecting wire harness puncture and crimping quality based on resistance measurement, characterized in that, Includes the following: Step 1: Using an X-ray machine to inspect numerous wire harness crimped terminal products, select several qualified products and several unqualified products. Step 2: Use a multimeter to measure the resistance values ​​of the selected qualified and unqualified products. Based on the distribution of the resistance values ​​of a single wire in the qualified products, set a comparison threshold in the computer to determine the resistance value of the product to be tested. Step 3: Prepare the product to be tested. The product to be tested is a wire harness piercing crimp terminal. The wire harness piercing crimp terminal includes a wire harness and a wire harness terminal. The wires inside the wire harness terminal are multiple and arranged in the same direction. The socket on the wire harness terminal is provided with a connecting spring corresponding to each wire. Step 4: Set up a resistance value detection system. The resistance value detection system includes a metal detection probe, a constant voltage source, a data acquisition card, a robotic arm, and a computer. The two ends of the metal detection probe are connected to a hollow bracket. The hollow bracket has internal wiring, and the metal detection probe is connected to the internal wires of the hollow bracket. The other end of the internal wires of the hollow bracket is connected to the constant voltage source, the data acquisition card, and the computer. Step 5: The robotic arm includes a first robotic arm and a second robotic arm, both of which are controlled by a computer. The first robotic arm is used to hold the wire harness terminal, and the second robotic arm is used to hold the hollow bracket. The computer controls the second robotic arm to insert the metal detection probe into the socket on the wire harness terminal, so that the metal detection probe makes contact with the connecting spring corresponding to each wire at the same time. Step 6: After completing Step 5, turn on the constant voltage source, collect the current value of the circuit through the data acquisition card and feed it back to the computer. The computer calculates the resistance value of each wire inside the wire harness terminal, compares the calculated resistance value of a single wire with the comparison threshold set in the computer. If the resistance value is greater than the comparison threshold, it is a defective product. The second robotic arm places the defective product in the defective storage area.

2. The method for detecting wire harness puncture and crimping quality based on resistance measurement according to claim 1, characterized in that: In step 1, the selected non-conforming products include at least two defects: improper wire harness insertion and missing wire harness. In step 2, the average resistance value of the individual wires of multiple qualified products is calculated, and this average resistance value is determined as the comparison threshold. At the same time, the resistance values ​​of the individual wires of multiple non-conforming products corresponding to the two defects are calculated, and the corresponding average resistance values ​​are calculated. The average resistance values ​​of the corresponding defect types are entered into the computer to determine the defect type of the detected non-conforming products.

3. The method for detecting wire harness puncture and crimping quality based on resistance measurement according to claim 1, characterized in that: In step 3, a wire through hole is opened on the wire harness terminal, and the wire enters the wire harness terminal through the wire through hole and is electrically connected to the connecting spring. A piercing is provided inside the wire harness terminal, and a terminal groove is opened on the outer shell of the wire harness terminal. The lower part of the connecting spring is a rectangular frame, and the lower part of the rectangular frame is a piercing. The piercing is fixed by the rectangular frame and the terminal groove, and the piercing is directly opposite the wire through hole.

4. The method for detecting wire harness puncture and crimping quality based on resistance measurement according to claim 1, characterized in that: In step 4, the hollow support is made of plastic.

5. The method for detecting wire harness puncture and crimping quality based on resistance measurement according to claim 1, characterized in that: In step 4, the metal detection probe is made of copper.

6. A method for detecting wire harness puncture and crimping quality based on resistance measurement according to claim 1 or 5, characterized in that: In step 4, the metal detection probe is a cylinder.

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