JP2011079434A - Method and system for manufacturing axle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a system for manufacturing an axle, which enhances the quality of a welding part and yield. <P>SOLUTION: This method for manufacturing the axle includes a first welding process for welding abutting parts 5a and 5b by a welding torch 31b based on a prescribed welding condition, a measuring process for measuring a welding current value supplied from a welding machine 33 to the welding torch 31 by a current measuring part 34 during the execution of the first welding process, and a decision process for calculating the difference between a waveform pattern formed by performing moving average processing for the welding current value measured in the measuring process and a waveform pattern formed by performing the moving average processing for a reference welding current value to decide the propriety of the welding condition in the first welding process based on the comparison of the difference with a prescribed threshold. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an automobile axle manufacturing method and an axle manufacturing system.

  A specially equipped vehicle such as a truck is equipped with an axle as an axle of a traveling device. As shown in Patent Document 1, the axle is formed by welding a spindle to an end of a cylindrical shaft body. Since the axle is an important part related to the traveling of the vehicle, high quality is required for the welded portion between the shaft body and the spindle.

Japanese Patent Laid-Open No. 11-115405

  The shaft body and the spindle are welded along a contact portion where the shaft body and the spindle are in contact with each other. The contact portion is generally welded using a welding robot. In such a welding robot, due to aging deterioration due to long-term use, for example, it may occur that the welding torch cannot be guided to an appropriate position or that an appropriate gas amount is not supplied. It is done. When such a problem due to aging occurs, a high-quality weld may not be formed. Further, the quality of the welded portion is deteriorated due to the abnormality of the contact portion, and those that cannot ensure sufficient welding strength are defective products, so that it is conceivable that the yield is lowered.

  An object of the present invention is to provide an axle manufacturing method and an axle manufacturing system capable of improving the quality of a welded portion and increasing the yield.

  In order to solve the above-described problems, the axle manufacturing method of the present invention includes a pre-welding process in which a spindle is brought into contact with both ends of a cylindrical shaft body, and a welding process in which welding is performed along a contact portion between the shaft body and the spindle. A first welding step of welding a pair of contact portions in which the spindle is in contact with both ends of the shaft body based on welding conditions, and a contact portion In the current measuring means possessed by the welding means for welding, a measuring step for measuring a welding current value when the contact portion is welded by the welding means, and a first welding current value measured in the measuring step. In order to properly weld the signal and the contact portion, a moving average process is applied to both of the reference signal consisting of a current value measured when welding is performed according to a predetermined condition, and the difference between them is calculated. Extracted as value, based on these judgment values, the contact portion, characterized in that it comprises a determination step of determining whether it has been welded in accordance with welding conditions.

  The axle manufacturing system of the present invention is an axle manufacturing system in which a spindle is brought into contact with both ends of a cylindrical shaft main body and welded along the contact portion of the shaft main body and the spindle. Welding means for welding based on predetermined welding conditions, current measuring means for measuring a welding current value supplied from the power source to the welding means during welding by the welding means, and a welding current value measured by the current measuring means The difference between the waveform pattern formed by applying the moving average process to the waveform pattern formed by applying the moving average process to the reference welding current value is calculated, and based on the comparison between the difference and the predetermined threshold value, the welding condition of the welding means is calculated. Determining means for determining whether or not it is possible.

  In this axle manufacturing method and axle manufacturing system, whether or not the contact portion is welded under a predetermined welding condition based on the welding current value supplied from the power source to the welding means when welding the contact portion. judge. In the present invention, for example, a welding current value that varies depending on various states of welding conditions such as a supply gas amount and a target deviation is measured, and based on this, it is determined whether or not welding has been performed under a predetermined welding condition. it can. Moreover, since the moving average process is performed with respect to the acquired welding current value, even if a noise component is mixed in the welding current value, the difference from the reference data can be accurately calculated. Thereby, when it is determined that welding is not performed under a predetermined welding condition, for example, the production of the axle can be interrupted or this can be notified, and the quality of the welded portion can be notified. It is possible to increase the yield while increasing the yield.

  Further, the axle manufacturing method of the present invention further includes a second welding step of welding the contact portion again by welding means based on a predetermined welding condition following the first welding step, And a welding condition resetting step for resetting the welding current value supplied from the power source to the welding means based on the pair of welding current values when the spindle is welded to both ends of the shaft measured in the measuring step. It is preferable. The axle manufacturing system according to the present invention further includes control means for controlling the welding means so that the contact portion is welded again based on a predetermined welding condition, and the control means is a shaft measured by the measuring means. It is preferable to control the welding current value supplied from the power source to the welding means based on a pair of welding current values when the spindle is welded to both ends of the welding power source.

  In this axle manufacturing method and axle manufacturing system, even if there is a difference in the welding quality of the pair of contact portions at the time of the first welding, the contact portions 5a and 5b at the time of the second welding are different. By resetting the welding current value, the welding quality can be adjusted to be equal to each other.

  In the axle manufacturing method of the present invention, the welding condition resetting step calculates an average welding current value from each of the pair of welding current values, and welds from the power source in the first welding step based on the ratio of these values. It is preferable to reset the welding current value so that the sum of the welding current value supplied to the means and the welding current value supplied from the power source to the welding means in the second welding step are equal to each other. In the axle manufacturing system of the present invention, the control means calculates an average welding current value from the pair of welding current values, and supplies the welding means from the power source in the first welding step based on the ratio of these values. It is preferable to control the welding current value so that the sum of the welding current value and the welding current value supplied from the power source to the welding means in the second welding step are equal to each other.

  In this axle manufacturing method and axle manufacturing system, the welding conditions when the first and second weldings are finished at the pair of contact portions can be made equal to each other, so that the welding quality is adjusted equally. can do.

  According to the present invention, it is possible to improve the quality of the welded portion and increase the yield.

It is the schematic of the axle manufactured by the manufacturing method of the axle which concerns on suitable one Embodiment of this invention. It is the block diagram which showed the function structure of the axle manufacturing system which concerns on suitable one Embodiment of this invention. It is a figure which shows an example of the signal output from the vibration detection part of FIG. It is a figure explaining the waveform processing analysis in the 1st signal processing part of FIG. It is the figure which showed an example of the welding current value output from the electric current measurement part of FIG. It is a flowchart which shows the manufacturing process of the axle which concerns on suitable one Embodiment of this invention. It is a flowchart which shows the manufacturing process of the axle which concerns on suitable one Embodiment of this invention. It is a figure which shows an example of the signal output from the vibration detection part of FIG. It is a figure explaining the waveform processing analysis result in the 1st signal processing part of Drawing 2. It is a figure which shows an example of the welding current value output from the electric current measurement part of FIG. It is a figure explaining the waveform process analysis result in the 2nd signal processing part of FIG.

  An axle manufacturing method according to a preferred embodiment of the present invention will be described with reference to FIGS. In the description of the drawings, the same reference numerals are assigned to the same elements, and duplicate descriptions are omitted. FIG. 1 is a schematic view showing an axle 1 manufactured by an axle manufacturing method of the present invention.

  The axle 1 manufactured by the axle manufacturing method of the present embodiment is an axle in a traveling device for a specially equipped vehicle such as a truck. As shown in FIG. 1, the axle 1 is formed by welding spindles 3 a and 3 b having a large diameter toward the shaft main body 2 at both ends of a cylindrical shaft main body 2.

  The shaft body 2 and the spindles 3a and 3b are welded by, for example, automatic welding using a welding system 30. Specifically, for example, as shown in FIG. 2, the spindles 3a and 3b are brought into contact with both ends of the shaft body 2 (pre-welding process), and the welding torch 31b or the shaft body 2 and the shaft main body 2 along the contact parts 5a and 5b. By rotating the spindles 3a and 3b, circumferential welds 6a and 6b are formed between the end of the shaft body 2 and the ends of the spindles 3a and 3b (process during welding).

  Hereinafter, the axle manufacturing system 10 for manufacturing the axle 1 by welding the shaft body 2 and the spindles 3a and 3b as described above and the method for manufacturing the axle 1 will be described in detail with reference to FIGS. explain.

  As shown in FIG. 2, the axle manufacturing system 10 includes a jig (contact means) 7, a vibration generator 11, a first vibration detector 12a, a second vibration detector 12b, and a first signal processor. 13, a first determination unit 15, a first control unit 16, a general control unit 21, a second signal processing unit 23, a second determination unit (determination unit) 25, and a second control unit (control unit). 26 and a welding system (welding means) 30 are mainly included.

  The jig 7 is a portion that causes the shaft body 2 and the spindles 3a and 3b to contact each other. The jig 7 supports the shaft body 2 and the spindles 3a and 3b, and brings the spindles 3a and 3b into contact with both ends of the shaft body 2 by a driving means (not shown).

  The vibration generator 11 is fixed to the outer peripheral surface of the shaft body 2 and is a part that generates solid propagation vibration under the control of the first controller 16. For example, a pulse generator can be adopted as the vibration generating unit 11. In this case, for example, an AE wave is input at a cycle (pulse width) of 100 to 500 ns.

  The first vibration detection unit 12a and the second vibration detection unit 12b are fixed to the outer peripheral surfaces of the spindles 3a and 3b sandwiching the shaft main body 2 and the contact portions 5a and 5b, respectively. , 5b to detect the solid propagation vibration propagating to the spindles 3a, 3b by the spindles 3a, 3b, respectively. As the first vibration detection unit 12a and the second vibration detection unit 12b, for example, an AE (Acoustic Emission) sensor can be adopted. In this case, for example, an AE wave having a peak frequency (center output) of 152.34 kHz. Is detected. The first vibration detection unit 12a and the second vibration detection unit 12b output an output signal corresponding to the detected intensity of the AE wave, for example, via an amplifier (not shown) whose band frequency is 40 kHz to 1.2 MHz. Output to the first signal processing unit 13.

  FIG. 3 is a diagram illustrating an example of signals output from the vibration detection units 12a and 12b. When there is no abnormality in the contact portions 5a and 5b, the first vibration detection portion 12a and the second vibration detection portion 12b have a small attenuation of the AE wave propagating through the contact portions 5a and 5b. For example, FIG. ), A signal having an amplitude peak first and gradually decreasing is output. On the other hand, when the first vibration detection unit 12a and the second vibration detection unit 12b have an abnormality in the contact portions 5a and 5b, for example, as shown in FIG. 3B, the amplitude is larger than that in FIG. Outputs a small signal. It should be noted that the waveform pattern of the output signal shown in FIG. 3B is substantially similar to that of the waveform of the output signal shown in FIG. The abnormality in the contact portions 5a and 5b refers to a case where there is a gap that cannot ensure a predetermined quality when welding the contact portions 5a and 5b.

  Returning to FIG. 2, the first signal processing unit 13 determines the presence or absence of abnormality in the contact portions 5a and 5b from the respective output signals detected by the first vibration detection unit 12a and the second vibration detection unit 12b. This is a part for extracting the judgment value necessary for. The first signal processing unit 13 characterizes the output signal by waveform processing analysis so that the first determination unit 15 described later can objectively determine whether there is an abnormality in the contact portions 5a and 5b.

  Hereinafter, waveform processing analysis which is one of the processes performed by the first signal processing unit 13 will be described. In this waveform processing analysis, first, as shown in FIG. 4, a moving average value μ of the output signal in a predetermined extraction width is obtained. Next, a sample line is set based on the standard deviation σ of the moving average value μ. The sample line can be obtained by multiplying the standard deviation σ by a predetermined value. For example, as shown in FIG. 4, by multiplying the standard deviation σ by −3.0 times, −1.5 times, +1.5 times, and +3.0 times, a sample line of −3σ, −1.5σ of A sample line, a sample line of + 1.5σ, and a sample line of + 3.0σ can be obtained. Next, the number of times that the output signal matches the value of a predetermined sample line (for example, + 3σ sample line) is calculated. The first signal processing unit 13 uses this number of times as a determination value and outputs the determination value to the first determination unit 15.

  Returning to FIG. 2, the first determination unit 15 is a unit that determines whether there is an abnormality in the contact portions 5 a and 5 b based on the determination value calculated by the first signal processing unit 13. Specifically, the first determination unit 15 determines the number of times the output signal output from the first vibration detection unit 12a matches the value of the sample line and the output signal output from the second vibration detection unit 12b. If both the number of coincidence with the reference value satisfy the reference data and these determination values are equal to each other, it is determined that there is no abnormality in both contact portions 5a and 5b. On the other hand, the first determination unit 15 matches the number of times the output signal output from the first vibration detection unit 12a matches the value of the sample line and the output signal output from the second vibration detection unit 12b matches the value of the sample line. If at least one of the number of times does not satisfy the reference data, or if both determination values satisfy the reference data but the determination values are not equal to each other, it is determined that there is an abnormality in at least one of the contact portions . The reference data is a value set for each sample line obtained by multiplying the standard deviation σ by a predetermined value, and is stored in the database unit 14.

  The first control unit 16 controls the jig 7 based on the presence / absence of the abnormality of the contact portions 5a and 5b determined by the first determination unit 15, or welds the contact portions 5a and 5b by the welding system 30. This is a part that sends a signal indicating that it may be implemented to the overall control unit 21. Specifically, the first control unit 16 determines that the shaft main body when at least one of the pair of determination values is 0 or when both of the pair of determination values are 1 or more and the values are different from each other. The jig 7 is controlled so that the contact between the spindle 2 and the spindles 3a and 3b is performed again. On the other hand, when both of the pair of determination values are 1 or more and the values are equal to each other, the first control unit 16 sends a signal indicating permission of welding of the contact portions 5a and 5b to the overall control unit 21. To do.

  The overall control unit 21 is a part that controls the entire axle manufacturing system 10, and includes a step of welding the contact portions 5 a and 5 b from a step of contacting the spindles 3 a and 3 b to both ends of the shaft body 2, or a contact portion. The transition from the step of welding 5a and 5b to the step of inspecting the welds 6a and 6b is controlled. Specifically, when the general control unit 21 receives a signal indicating permission of welding of the contact parts 5a and 5b sent from the first control unit 16, the contact parts 5a and 5b are welded to the second control unit 26. Command to do. In addition, when a signal indicating inspection permission of the welded portions 6a and 6b sent from the second control unit 26 is received, the third control unit (not shown) is instructed to inspect the welded portions 6a and 6b.

  The 2nd control part 26 is a part which controls the welding system 30 so that contact part 5a, 5b is welded on a predetermined welding condition, The 1st welding process control part 26a and the 2nd welding process control part 26b are carried out. Have. The first welding process control unit 26a is a part that controls the so-called first-pass welding in which the contact portions 5a and 5b in which the shaft body 2 and the spindles 3a and 3b are contacted by the jig 7 are welded. The second welding process control unit 26b is a part that controls so-called second-pass welding, in which the same portion is welded again after the first-pass welding described above.

  The first welding process control unit 26a controls the welding system 30 so that the welding current value during welding becomes a reference value (predetermined condition). The reference value here refers to a welding current value for forming an optimum welded portion, and is set based on the contact state and the material of the workpiece. The second welding process control unit 26b will be described in detail later.

  The welding system 30 is a part that welds the contact portions 5 a and 5 b, and is controlled by the second control unit 26. The welding system 30 mainly includes a welding robot 31 having an arm 31a and a welding torch 31b, a welding machine (power source) 33, and a current measuring unit 34. The arm 31a can freely move the position of the welding torch 31b attached to the tip. The welding torch 31b is supplied with welding current, shield gas, wire, and the like by a welding machine 33 described later, and welds the contact portions 5a and 5b. The welding machine 33 controls the supply of electric power, shielding gas, and wires to the welding torch 31b. In addition, as the welding machine 33, a MIG welding machine etc. are employable, for example. The current measuring unit 34 is a part that measures a welding current value supplied from the welding machine 33 to the welding torch 31b. The current measuring unit 34 outputs the measured welding current value to the signal processing unit 23.

  FIG. 5 is a diagram illustrating an example of a welding current value output from the current measuring unit 34. For example, when the contact portions 5a and 5b are normally welded under predetermined welding conditions, the current measuring unit 34 mainly has a welding current having a value of 350 to 500 A, for example, as shown in FIG. Output the value. On the other hand, the current measuring unit 34 has a value of mainly 350 to 500 A as shown in FIG. 5B, for example, when the contact portions 5a and 5b cannot be normally welded under predetermined welding conditions. A welding current value different from that shown in FIG. In addition, when it cannot weld on predetermined | prescribed welding conditions in contact part 5a, 5b, for example, there exists abnormality in the supply amount of gas, or any aim generate | occur | produces.

  Returning to FIG. 2, the second signal processing unit 23 determines whether or not welding can be performed under predetermined welding conditions in the contact portions 5 a and 5 b based on the welding current value output from the current measurement unit 34. This is a part for extracting necessary judgment values. Specifically, the second signal processing unit 23 performs moving averaging on a waveform pattern obtained by subjecting the welding current value obtained from the current measuring unit 34 to moving average processing, and reference data stored in the database unit 24. The difference from the processed waveform pattern is calculated. The second signal processing unit 23 uses the difference calculated in this way as a determination value and outputs the determination value to the second determination unit 25. Here, the predetermined conditions include optimum welding conditions set based on the contact state, material, and the like when welding the contact portions 5a and 5b. The reference data is data obtained by measuring a welding current value when the contact portion is normally welded according to predetermined welding conditions.

  Returning to FIG. 2, the second determination unit 25 determines whether or not welding can be performed under predetermined welding conditions in the contact portions 5 a and 5 b based on the determination value output from the second signal processing unit 23. Specifically, when there is a difference between the welding current value obtained from the current measurement unit 34 and the reference data stored in the database unit 24, the contact portions 5a and 5b It is determined that welding has not been performed under the welding conditions. On the other hand, when there is almost no difference between the welding current value obtained from the current measuring unit 34 and the reference data stored in the database unit 24, the contact portions 5a and 5b are provided with predetermined welding. It is determined that welding has been performed under the conditions. Note that whether or not there is a difference between the welding current value obtained from the current measuring unit 34 and the reference data stored in the database unit 24 can be determined by the determination value calculated in the second signal processing unit 23. Is possible.

  The second welding process control unit 26b is configured to measure 1 measured by the current measurement unit 34 when the second determination unit 25 determines that the contact portions 5a and 5b are welded under predetermined welding conditions. Based on the pair of welding current values of the pass, the welding current value supplied from the welding machine 33 to the welding torch 31b when the second pass is welded is reset. Specifically, an average welding current value is calculated from a pair of welding current values, and based on the ratio of these values, the welding current value supplied to the welding torch 31b from the welding machine 33 in the first pass, and 2 In the pass, the welding current value is reset so that the sum of the welding current value supplied from the welding machine 33 to the welding torch 31b becomes equal to each other.

  Hereinafter, a method for manufacturing the axle will be described with reference to flowcharts showing the manufacturing process of the axle in FIGS. 6 and 7. As shown in FIG. 2, first, the vibration generating portion 11 is arranged on the outer peripheral surface of the shaft main body 2 which is a part forming the axle 1, and the outer peripheral surfaces of the spindles 3 a and 3 b welded to both ends of the shaft main body 2. The vibration detectors 12a and 12b are arranged in the (step S1).

  Returning to FIG. 6, next, the spindles 3a and 3b are brought into contact with both ends of the shaft body 2 (step S2). Next, solid propagation vibration is generated from the vibration generation unit 11, and the AE wave propagated from the shaft body 2 to the spindles 3a and 3b through the contact portions 5a and 5b is detected by the pair of vibration detection units 12a and 12b ( Step S3). Note that the period of the AE wave is, for example, 150 ns.

  Next, a determination value necessary for determining whether or not there is an abnormality in the contact portions 5a and 5b is calculated from a pair of output signals respectively acquired by the vibration detection units 12a and 12b (step S4). Specifically, first, a moving average value μ in a predetermined extraction width (in the example of FIG. 8, 150 ns, which is an AE wave input period) is obtained, and a standard deviation σ based on the moving average value μ is calculated. Next, a sample line obtained by multiplying the calculated standard deviation σ by a predetermined value (in the example of FIG. 8, five times the standard deviation σ) is set. Then, the number of times that the output signal matches the value of the sample line is calculated, and the determination value is acquired as shown in FIG. FIG. 9A shows the result of waveform processing analysis of only the waveform (0.045 s to 0.06 s) corresponding to M1 from the time series waveforms shown in FIG.

  Returning to FIG. 6, next, based on this determination value, the presence or absence of abnormality in the contact portions 5a and 5b is determined (step S5). Specifically, as shown in FIG. 9A, if the output signal matches the value of the sample line at least once for the + 5σ sample line, there is an abnormality in the contact portions 5a and 5b. Judge that there is no. On the other hand, as shown in FIG. 9B, when the output signal never matches the value of the sample line with respect to the + 5σ sample line, it is determined that the contact portions 5a and 5b are abnormal. To do. Here, the criterion for determining whether or not there is an abnormality in the contact portions 5a and 5b is that the number of times that the output signal matches the value of the sample line with respect to the sample line 5σ is one or more times, but is not limited to this. The determination criterion can be set according to the desired contact state rather than the desired one.

  Returning to FIG. 6, next, it is determined whether or not the subsequent welding process can be performed based on the determination of the presence or absence of abnormality in both the contact portions 5 a and 5 b determined in step S <b> 5 (step S <b> 6). Specifically, if at least one of the pair of determination values calculated in step S4 is 0, that is, if it is determined in step S5 that both the contact portions 5a and 5b are abnormal, It is determined that it is impossible to perform a welding process (step S10 to be described later), and the process returns to the step of contacting the shaft body 2 and the spindles 3a and 3b (step S2) (step S6: No). On the other hand, if both of the pair of determination values calculated in step S4 are 1 or more, that is, if it is determined in step S5 that there is no abnormality in both of the contact portions 5a and 5b, in a later process. It is determined that a certain welding process (step S10 to be described later) can be performed, and the process proceeds to step S7 (step S6: acceptable).

  Next, it is determined whether the pair of determination values calculated in step S4 are equal to each other (step S7). Specifically, when the pair of determination values calculated in step S4 are equal to each other (step S7: YES), the welding currents when welding the contact portions 5a and 5b are adjusted to be equal to each other ( Step S8). On the other hand, if the pair of determination values are different from each other (step S7: NO), the process returns to the step of abutting the shaft body 2 and the spindles 3a and 3b (step S2).

  Next, as shown in FIG. 7, according to the welding current value set in step S8, the pair of contact portions 5a and 5b are welded (step S10: first welding step), and the contact portions 5a and 5b are connected. Each welding current value supplied from the welding machine 33 to the welding torch 31b when welding is measured (step S11: measurement process).

  Next, based on the pair of welding current values acquired in step S11, a determination value necessary for determining whether or not the abutting portions 5a and 5b can be performed under predetermined welding conditions is extracted (step S12). . Specifically, as shown in FIG. 10 (a), a moving average process is performed on both the welding current value obtained from the current measurement unit 34 and the reference data stored in the database unit 14 to obtain mutual values. And a determination value as shown in FIG. 11A or FIG. 11B is calculated.

  Returning to FIG. 7, next, based on this determination value, it is determined whether or not the contact portions 5a and 5b can be implemented under predetermined welding conditions (step S13: determination step). Specifically, as shown in FIG. 11A, when the determination value exceeds a predetermined threshold (for example, 50A), the contact portions 5a and 5b are welded under predetermined welding conditions. Judge that there was no. On the other hand, as shown in FIG. 11B, when the determination value does not exceed a predetermined threshold (for example, 50 A), it is determined that the contact portions 5a and 5b are welded under predetermined welding conditions. . The predetermined threshold value is not limited to 50A, and can be arbitrarily set based on the magnitude of the difference from the reference data.

  Returning to FIG. 8, when it is determined in step S13 that at least one of the pair of contact portions 5a and 5b is not welded under a predetermined welding condition, a series of processing ends here (step S13). :no). In this case, the user or the like may be notified that 5a and 5b are not welded under a predetermined welding condition.

  On the other hand, when it is determined in step S13 that the contact portions 5a and 5b are welded under a predetermined welding condition (step S13: Yes), it is determined whether the pair of welding current values measured in step S11 are equal to each other. (Step S14).

Here, when there is a difference between the values of the pair of welding current values measured in step S11 (step S14: NO), the welding current value supplied from the welding machine 33 to the welding torch 31b is reset (step S15). : Welding condition resetting process). Specifically, when the average welding current value is calculated from a pair of welding current values and the values are different from each other, the welding current value when welding the contact portion having the smaller average welding current value again is determined. It is reset so that the standard welding current value of the second pass × (larger average welding current value / smaller average welding current value). On the other hand, when the values of the pair of welding current values measured in step S11 are equal to each other (step S14: YES), the welding current values at the time of welding in step S11 are maintained (step S16: reset welding conditions). Process). In calculating the average welding current value from the pair of welding current values, the average welding current value may be based on all measured welding current values, or a value calculated by moving average processing may be used.
Next, according to the welding current value set in step S15 or step S16, the contact portions 5a and 5b are welded again (step S17: second welding step). In addition, when welding again in step S17, you may implement after performing correction work, such as a bead grind, with respect to the welding parts 6a and 6b formed in step S10.

  Next, the presence or absence of abnormality in the welded portions 6a and 6b (see FIG. 1) welded in step S17 is determined (step S18). Specifically, the vibration generating unit 11 that generates AE waves is disposed on the outer peripheral surface of the tapered portion of one spindle 3 a, and the vibration detecting unit 12 that detects AE waves is disposed on the outer peripheral surface of the shaft body 2. Next, an AE wave is generated from the vibration generating unit 11, the AE wave propagated from the spindle 3 through the welded portion to the shaft body 2 is detected by the vibration detecting unit 12, and based on an output signal from the vibration detecting unit 12. Then, the presence or absence of abnormality in one welded portion is determined. Further, the vibration generating portion 11 for generating the AE wave is rearranged on the outer peripheral surface of the tapered portion of the other spindle 3a, and the presence or absence of abnormality in the other welded portion is determined by the same method as described above.

  As described above, in the axle manufacturing system and the axle manufacturing method according to the present embodiment, when welding the contact portions 5a and 5b, a predetermined current is supplied based on the welding current value actually supplied from the welding machine 33. It is determined whether or not the contact portions 5a and 5b are welded under welding conditions. In the present invention, for example, a welding current value that varies depending on various states of welding conditions such as a supply gas amount and a target deviation is measured, and based on this, it is determined whether or not welding has been performed under a predetermined welding condition. it can. Moreover, since the moving average process is performed with respect to the acquired welding current value, even if a noise component is mixed in the welding current value, the difference from the reference value can be calculated with high accuracy. . Thereby, when it is determined that welding is not performed under a predetermined welding condition, the production of the axle 1 can be interrupted or this can be notified. It is possible to improve the quality of 5b and increase the yield.

  Further, in the axle manufacturing system and the axle manufacturing method according to the present embodiment, subsequent to step S10 (first welding step), the contact portions 5a and 5b are welded again by the welding system 30 based on predetermined welding conditions. Step S17 (second welding process) is further provided, and the welding current value supplied from the welding machine 33 to the welding torch 31b is reset based on the pair of welding current values measured in Step S11 (measurement process). S15, 16 (welding condition resetting step). Thereby, even if there is a difference in the welding quality of the pair of contact portions 5a, 5b in the first pass, by resetting the welding current values of both contact portions 5a, 5b in the second pass, The welding quality can be adjusted to be equal to each other.

  Further, in the axle manufacturing system and the axle manufacturing method of the present embodiment, in step S15, the average welding current values are calculated from the pair of welding current values, respectively. Based on (larger other average welding current value / smaller one average welding current value), the welding current value at the time of welding the one contact portion having a smaller average welding current value is reset. As a result, the welding conditions at the contact portions 5a and 5b at the end of the first pass and the second pass can be made equal to each other.

  The present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above embodiment. The present invention can be modified in various ways as described below without departing from the scope of the invention.

  In the axle manufacturing method of the above-described embodiment, the example in which the welding current value supplied from the welding machine 33 to the welding torch 31b is measured in the current measuring unit 34 has been described, but the present invention is not limited thereto. The welding current value may be calculated indirectly by measuring the welding voltage between the welding machine 33 and the welding torch 31b.

  In the method for manufacturing an axle according to the above embodiment, the example including step S6 and step S7 has been described. However, the present invention is not limited to this. For example, even in the method starting from the welding process of the first pass in step S10, the contact is made under a predetermined welding condition based on the welding current value supplied from the power source to the welding means when welding the contact portion. Since it can be determined whether or not the part is welded, it is possible to obtain the same effect as in the above-described embodiment that it is possible to determine whether or not the part is welded under a predetermined welding condition.

  In the axle manufacturing system 10 of the above embodiment, the second signal processing unit 23 has been described by taking an example in which the moving average process is performed on the welding current value. However, the present invention is not limited to this example. Etc. may be applied to calculate the difference from the reference value data.

  In the axle manufacturing system 10 of the above-described embodiment, the first control unit 16 is configured to perform the contact between the shaft body 2 and the spindles 3a and 3b again when at least one of the pair of determination values is 0. Although the example which controls the tool 7 was given and demonstrated, it is not limited to this. For example, when at least one of the pair of determination values is 0, the first control unit 16 may urgently stop the entire axle manufacturing system 10 or may provide a notification unit that notifies the user of this. The structure provided may be sufficient.

  In the method for manufacturing an axle according to the above embodiment, 5σ, which is 5 times the standard deviation σ, is set in setting the sample line. However, the present invention is not limited to this, for example, 1.5σ, which is 1.5 times the standard deviation σ. Alternatively, 3σ that is three times the standard deviation σ may be set.

  DESCRIPTION OF SYMBOLS 1 ... Axle, 2 ... Shaft body, 3a, 3b ... Spindle, 5a, 5b ... Contact part, 6a, 6b ... Welding part, 7 ... Jig, 10 ... Axle manufacturing system, 11 ... Vibration generating part, 12a, 12b ... vibration detection unit, 13 ... first signal processing unit, 14 ... first database unit, 15 ... first determination unit, 16 ... first control unit, 21 ... general control unit, 23 ... second signal processing unit, 24 ... 2nd database part, 25 ... 2nd determination part, 26 ... 2nd control part, 26a ... 1st welding process control part, 26b ... 2nd welding process control part, 30 ... Welding system, 31 ... Welding robot, 31a ... Arm 31b ... welding torch, 33 ... welder, 34 ... current measuring part.

Claims (6)

A method of manufacturing an axle, comprising: a pre-welding step in which a spindle is brought into contact with both ends of a cylindrical shaft main body; and a mid-welding step in which welding is performed along a contact portion of the shaft main body and the spindle,
The process during welding includes
A first welding step of welding the abutting portion with welding means based on predetermined welding conditions;
A measurement step of measuring a welding current value supplied from a power source to the welding means during the first welding step by means of a current measurement means;
A difference between a waveform pattern formed by performing a moving average process on the welding current value measured in the measurement step and a waveform pattern formed by performing a moving average process on a reference welding current value is calculated, and the difference between the difference and a predetermined threshold value is calculated. A determination step for determining whether or not the welding condition in the first welding step is based on the comparison;
A method of manufacturing an axle, comprising: Subsequent to the first welding step, further comprising a second welding step of welding the contact portion again with the welding means based on a predetermined welding condition,
In the second welding step, the welding current value supplied from the power source to the welding means is based on a pair of the welding current values when the spindle is welded to both ends of the shaft measured in the measurement step. The method for manufacturing an axle according to claim 1, further comprising a welding condition resetting step for resetting.   The welding condition resetting step calculates an average welding current value from the pair of welding current values, respectively, and based on the ratio of these values, the power supplied from the power source to the welding means in the first welding step. 3. The welding current value is reset so that a sum of a welding current value and the welding current value supplied from the power source to the welding means in the second welding step are equal to each other. A method for manufacturing the axle according to claim 1. An axle manufacturing system having a contact means for contacting a spindle to both ends of a cylindrical shaft body, and a welding means for welding along the contact portion of the shaft body and the spindle,
Current measuring means for measuring a welding current value supplied from a power source to the welding means during welding by the welding means;
A difference between a waveform pattern obtained by subjecting the welding current value measured by the current measuring means to a moving average process and a waveform pattern obtained by subjecting the reference welding current value to a moving average process is calculated, and the difference and a predetermined threshold value are calculated. Determination means for determining whether or not welding conditions in the welding means based on the comparison,
An axle manufacturing system comprising: A control means for controlling the welding means so as to weld the contact portion again based on a predetermined welding condition;
The control means controls a welding current value supplied from the power source to the welding means based on a pair of welding current values when the spindle is welded to both ends of the shaft measured by the measuring means. The axle manufacturing system according to claim 4.   The control means calculates an average welding current value from the pair of welding current values, and based on the ratio of these values, the welding current value supplied from the power source to the welding means in the first welding step. 6. The axle according to claim 5, wherein the welding current value is controlled so that a sum of the welding current value supplied from the power source to the welding means in the second welding step is equal to each other. Manufacturing system.

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