Method and system for evaluating capability index of coil winding process

Abstract

The invention belongs to the field of product production process quality control, and particularly relates to a method and system for evaluating a coil winding process capability index, and the method is characterized in that the method comprises the following steps: 1, winding a first coil, measuring the length outer diameter and the resistance of an enameled wire, and calculating the resistivity rho of the enameled wire; 2, winding subsequent coils, and calculating the resistance of each wound coil in the same batch according to a formula R = 4L * rho / (Pid2) by taking the length L of each wound coil obtained by a length counting mechanism and the resistivity rho and the diameter d of the enameled wire in the step 1 as parameters; 3, the resistance values, obtained in the step 1 and the step 2, of the coils wound in the same batch serve as parameters, the winding process capability index CP of the coils in the batch is obtained through calculation, and the system comprises an electronic length counting mechanism connected with the winding mechanism, an upper computer electrically connected with the electronic length counting mechanism and a power supply module electrically connected with the upper computer. According to the invention, the capability index of the coil winding process is automatically evaluated, and the production efficiency is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the field of product production process quality control, and specifically refers to a method and system for evaluating the capability index of a coil winding process. Background Art

[0002] Process Capability Index (PCI) is an important indicator for measuring process quality. It reflects the ability of the process to meet product specification requirements under stable conditions.

[0003] Coil products are key components in electromagnetic conversion equipment, and are also basic elements in the fields of motor drive, sensor application, electromagnetic braking, etc. By statistically analyzing the resistance of all coil products wound in the same batch, evaluating the coil winding process capability index can detect the degree to which the winding process meets the coil product quality standards. When the coil winding process capability index is too low, the coil winding equipment needs to be improved to ensure the stability of the quality of the coil products wound successively. The existing method for evaluating the coil winding process capability index generally includes the following steps: winding coils one by one, measuring the coil resistance value one by one, statistically analyzing the resistance value, and combining the process capability index formula to obtain the coil winding process capability index. To measure the coil resistance value, it is necessary to weld the lead wires of the wound coil products one by one, and then use a meter to detect the resistance. The manual resistance detection method is inefficient. When the enameled wire used is of a high grade, it is necessary to chemically remove the paint before welding the lead wires and testing the meter, which further reduces the work efficiency. Summary of the invention

[0004] One of the purposes of the present invention is to provide a method for evaluating the capability index of a coil winding process with high working efficiency, so as to overcome the problems existing in the prior art.

[0005] The technical solution for achieving the above-mentioned purpose includes the following contents.

[0006] A method for evaluating a coil winding process capability index includes using a length measuring mechanism to obtain a length L of an enameled wire for winding a coil, and further includes the following steps:

[0007] Step 1: Wind the first coil, measure the coil resistance R1 and the enameled wire diameter d, and use the formula resistivity ρ = πd 2 R1 / 4L is used to calculate the resistivity ρ of the enameled wire;

[0008] Step 2, winding the subsequent coils, taking the length L of each subsequent winding coil obtained by the length measuring mechanism and the resistivity ρ and the diameter d of the enameled wire in step 1 as parameters, according to the formula R = 4L·ρ / (πd 2), calculate the resistance of each subsequent coil of the same batch to obtain R2, R3, R4, ... Rn;

[0009] Step 3: Using the resistance values ​​R1, R2, R3, R4, ... Rn of the coils wound in the same batch obtained in Step 1 and Step 2 as parameters, calculate the coil winding process capability index C of the batch of coils. P , the calculation formula is as follows,

[0010]

[0011] In the formula, is the range, i.e., the difference between the maximum and minimum values ​​of the resistance values ​​R1, R2, R3, R4, ... Rn; d2 is the range coefficient, i.e., the range Rn, σ is the standard deviation of the normal distribution, and T is the allowable range of variation of the design resistance value parameters of the coils in this batch.

[0012] Furthermore, the number of coils wound in the same batch is not less than 20, and the more statistical samples there are, the more reliable the index is.

[0013] Based on the above-mentioned method for evaluating the coil winding process capability index, the present case also provides a system for evaluating the coil winding process capability index, including an electronic length measuring mechanism connected to the winding mechanism, and a host computer electrically connected to the electronic length measuring mechanism, wherein a resistance calculation module and a process capability index calculation module are installed in the host computer, the host computer receives the enameled wire length output by the electronic length measuring mechanism, the resistance calculation module calculates the coil resistance according to the enameled wire length, and the process capability index calculation module calculates the coil winding process capability index according to the coil resistance.

[0014] Furthermore, the electronic length measuring mechanism includes a grating disk and a photoelectric detection device. The grating disk is connected to the transmission wheel. When winding the coil, the enameled wire is wound around the transmission wheel for one or several turns. The enameled wire drives the transmission wheel to rotate, and the grating disk rotates together with the transmission wheel. When the grating disk rotates, the photoelectric detection device will detect the change in light and convert it into an electrical signal. By counting the electrical signal, the rotation angle and number of revolutions of the grating disk can be determined. Based on the known circumference and number of revolutions of the grating disk, the length of the enameled wire can be calculated.

[0015] The above-mentioned method and system for evaluating the coil winding process capability index are based on the existing technology that can detect and record the length of the wound enameled wire (for example, using a photoelectric encoder device). The recorded enameled wire length value is input into a computer, and the resistance of the coil product is obtained in combination with the resistance formula. Based on the obtained resistance value of the same batch of coil products, the process capability index calculation module is used to calculate the coil winding process capability index. Compared with the method of manually welding the lead wire to measure the resistance used in the prior art, the method of the present invention realizes automatic evaluation of the coil winding process capability index, which greatly improves efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a system for evaluating the capability index of a coil winding process of the present invention;

[0017] Figure 2 This is a flow chart of manual measurement and calculation of the first coil product of the present invention;

[0018] Figure 3 This is a flow chart of the present invention using a computer to perform data processing and statistics to obtain the coil winding process capability index;

[0019] Figure 4 It is a schematic diagram of the working of the length measuring mechanism of the embodiment. DETAILED DESCRIPTION

[0020] The present invention is specifically described below with reference to the embodiments.

[0021] See also Figures 1 to 4 In this embodiment, an automatic winding machine is used to wind 25 coil products at a time. The automatic winding machine is provided with a length measuring mechanism of a photoelectric encoder. When working, the length measuring mechanism is connected to a computer. The computer is provided with a data processing system. The length measuring mechanism transmits the length of the enameled wire obtained each time to the computer. The method for evaluating the capability index of the coil winding process of this batch is as follows. The specific steps are as follows:

[0022] Step 1, see Figure 2 , wind the first coil product, obtain the enameled wire length L1, measure the coil resistance value R1 and the enameled wire diameter d, and according to the formula resistivity ρ=πd 2 R1 / (4L1) is used to deduce the resistivity ρ of the enameled wire, and the diameter d and the resistivity ρ of the enameled wire are sent to the computer data processing system as initial values;

[0023] Step 2, see Figure 3 , wind the subsequent 24 coil products, taking the length of the enameled wire of each subsequent winding coil obtained by the length measuring mechanism, and the resistivity ρ and the enameled wire diameter d in step 1 as parameters, according to the formula R = 4L·ρ / (πd 2), the data processing system calculates the resistance of the subsequent 24 winding coils to obtain R2, R3, R4, ... R25;

[0024] Step 3, see Figure 2 , using the resistance values ​​R1, R2, R3, R4, ... R25 of the 25 coil products obtained in step 1 and step 2 as parameters, the data processing system calculates the coil winding process capability index C of this batch of coils P , the calculation formula is as follows,

[0025]

[0026] In the formula, is the range, i.e. the difference between the maximum and minimum values ​​of the resistance values ​​of the 25 coil products; d2 is the range coefficient, i.e. The ratio of σ to the mean of the 25 resistance values, σ is the standard deviation of the normal distribution, T is the allowable range of variation of the design resistance value parameter of the coil product of this batch,

[0027] In this embodiment, the length measuring mechanism adopts a photoelectric encoder mechanism to measure the length. Figure 4 The photoelectric encoder is composed of a grating disk and a photoelectric detection device. The grating disk is connected to the grating drive wheel. Before winding, the wire is wound around the grating drive wheel. When winding, the enameled wire belt and the grating drive wheel rotate, and the grating disk rotates. The photoelectric detection device detects the change of light and converts it into an electrical signal. By counting the electrical signals, the rotation angle and number of revolutions of the grating disk can be determined. According to the known circumference and number of revolutions of the grating disk, the length L of the enameled wire can be calculated. The coil winding process capability index evaluation method and system of the present invention utilizes the length value provided by the length metering device when collecting the resistance value data of the coil product and converts it into a resistance value. Compared with the prior art method of manually measuring the resistance value and then evaluating the coil winding process capability index, the present invention has the advantages of high efficiency and simple operation.

Claims

1. A method for evaluating the capability index of a coil winding process, characterized in that: The method includes using a length measuring mechanism to obtain the length L of the enameled wire of the winding coil, and further includes the following steps: Step 1: Wind the first coil, measure the coil resistance R1 and the enameled wire diameter d, and use the formula resistivity ρ = πd 2 R1 / 4L is used to calculate the resistivity ρ of the enameled wire; Step 2, winding the subsequent coils, taking the length L of each subsequent winding coil obtained by the length measuring mechanism and the resistivity ρ and the diameter d of the enameled wire in step 1 as parameters, according to the formula R = 4L·ρ / (πd 2 ), calculate the resistance of each subsequent coil of the same batch to obtain R2, R3, R4, ... Rn; Step 3: Using the resistance values ​​R1, R2, R3, R4, ... Rn of the coils wound in the same batch obtained in Step 1 and Step 2 as parameters, calculate the coil winding process capability index C of the batch of coils. P , the calculation formula is as follows, In the formula, R is the range, that is, the difference between the maximum and minimum values ​​among the resistance values ​​R1, R2, R3, R4, ... Rn; d2 is the range coefficient, that is, the ratio of the range R to the mean of the resistance values ​​R1, R2, R3, R4, ... Rn, σ is the standard deviation of the normal distribution, and T is the allowable range of variation of the design resistance value parameters of the coils of this batch.

2. The method for evaluating the coil winding process capability index according to claim 1, characterized in that: The number of coils wound in the same batch is not less than 20.

3. A system for evaluating the capability index of a coil winding process, characterized in that: It includes an electronic length measuring mechanism connected to the winding mechanism and a host computer electrically connected to the electronic length measuring mechanism. The host computer is installed with a resistance calculation module and a process capability index calculation module. The host computer receives the enameled wire length output by the electronic length measuring mechanism. The resistance calculation module calculates the coil resistance according to the enameled wire length. The process capability index calculation module calculates the coil winding process capability index according to the coil resistance.

4. The system for evaluating the coil winding process capability index according to claim 3, characterized in that: The electronic length measuring mechanism includes a grating disk and a photoelectric detection device. The grating disk is connected to a transmission wheel. When winding a coil, the enameled wire is wound around the transmission wheel for one or several turns. The enameled wire drives the transmission wheel to rotate, and the grating disk rotates together with the transmission wheel. When the grating disk rotates, the photoelectric detection device detects the change of light and converts it into an electrical signal. By counting the electrical signals, the rotation angle and number of revolutions of the grating disk can be determined. According to the known circumference and number of revolutions of the grating disk, the length of the enameled wire can be calculated.

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