JP5992709B2 - Spot welding method, spot welding apparatus and spot welding program - Google Patents

Description

  The present invention relates to a spot welding method, a spot welding apparatus, and a spot welding program.

  Conventionally, a method of manufacturing a side structure of a railway vehicle by joining a frame and an outer plate by spot welding is known (see Patent Document 1).

Japanese Patent No. 2953354

  An object of the present invention is to provide a spot welding method, a spot welding apparatus, and a spot welding program capable of optimizing the arrangement of spot welding positions in consideration of the stress concentration occurring in the vicinity of a spot welding spot. .

Spot welding method according to the present invention, a first member and a second member constituting the railway car body structure, a spot welding method for joining by spot welding using a spot welding apparatus, calculation of the spot welding apparatus The means is based on the first to nth spot layout data respectively indicating the first to nth (n is a natural number of 2 or more) arrays of the planned positions for spot welding the first member and the second member. The first step of calculating the stress at each planned position and the selection means of the spot welding apparatus , based on the results of comparing the magnitudes of the stresses calculated in the first step, A second step of selecting one spot layout data having a low stress concentration from the spot layout data of the first step, and according to a planned position indicated by the spot layout data selected in the second step The first member and the second member have a third step of spot welding, in the second step, the selection means of the spot welding apparatus, of the m (m is a natural number 1 to n) Spot When the maximum value of the magnitudes of stresses at each predetermined position of the layout data is the m-th value, spot layout data indicating the minimum value among the m-th values is selected as one spot layout data .

In the spot welding method according to the present invention, the stress at each planned position is calculated for each of a plurality of spot layout data. Subsequently, one spot layout data having a small stress concentration is selected from a plurality of spot layout data based on the result of comparing the magnitudes of the calculated stresses. Therefore, according to the selected spot layout data, spot welding of the first member and the second member is performed, and the arrangement of the spot welding positions is made appropriate in consideration of the stress concentration generated in the vicinity of the spot welding location. it can. In the spot welding method according to the present invention, spot layout data indicating the minimum value among the m-th values is selected as one spot layout data. Therefore, spot layout data with the smallest stress concentration can be selected from among a plurality of spot layout data.

  The first member may be a side beam constituting the railway vehicle structure, and the second member may be a door frame constituting the railway vehicle structure.

  The first member may be an outer plate constituting the railway vehicle structure, and the second member may be a long member constituting the railway vehicle structure.

  In the third step, the first member and the second member may be indirect spot welded.

A spot welding apparatus according to the present invention is a spot welding apparatus that controls a welding robot that joins a first member and a second member constituting a railway vehicle structure by spot welding, and includes a first member and a second member. Storage means for storing first to n-th spot layout data respectively indicating first to n-th (n is a natural number of 2 or more) arrangements of spot positions to be spot-welded with each member, and stored in the storage means Based on the first to n-th spot layout data, the calculation means for calculating the stress at each planned position and the result of comparing the magnitude of each stress calculated by the calculation means, the first to n-th spot layout data. A selection means for selecting one spot layout data having a small stress concentration from the spot layout data, and a planned position indicated by the spot layout data selected by the selection means. A first member and a second member and a control means for controlling the welding robot to spot welding, selection means, the m (m is a natural number 1 to n) each appointment spot layout data the maximum value of the magnitude of the stress at the position when the value of the m, you select the spot layout data indicating the minimum value among the values of the m as the one spot layout data.

  In the spot welding apparatus according to the present invention, the calculation means calculates the stress at each planned position for each of the plurality of spot layout data. The selection means selects one spot layout data having a small stress concentration from the plurality of spot layout data based on the result of comparing the magnitudes of the stresses calculated by the calculation means. Therefore, the control means controls the welding robot so as to spot weld the first member and the second member in accordance with the selected spot layout data, thereby taking into account the stress concentration generated in the vicinity of the spot welding location. Thus, the arrangement of the spot welding positions can be optimized.

A spot welding program according to the present invention is a spot welding program for controlling a welding robot that joins a first member and a second member constituting a railway vehicle structure by spot welding, and includes a computer and a first member. Storage means for storing first to n-th spot layout data respectively indicating first to n-th (n is a natural number of 2 or more) arrays of planned positions for spot welding of the second member and the second member; Based on the first to nth spot layout data stored, the calculation means for calculating the stress at each planned position, and the results of comparing the magnitudes of the stresses calculated by the calculation means, Selecting means for selecting one spot layout data having a small stress concentration from the nth spot layout data, and the spot layer selected by the selecting means; According to a schedule position indicated Todeta, and control means for controlling the welding robot as the first member and the second member is spot welded, to function as a selecting means is a natural number of the m (m is 1~n ) When the maximum value of the magnitudes of the stress at each predetermined position of the spot layout data is the mth value, the spot layout data indicating the minimum value among the mth values is selected as one spot layout data. The

  In the spot welding program according to the present invention, the computer is caused to function as calculation means for calculating the stress at each planned position for each of the plurality of spot layout data. Based on the result of comparing the magnitudes of the stresses calculated by the calculation means, the computer is caused to function as selection means for selecting one spot layout data having a low stress concentration from a plurality of spot layout data. Therefore, by causing the computer to function as a control means for controlling the welding robot so as to spot weld the first member and the second member in accordance with the selected spot layout data, the stress generated in the vicinity of the spot welding location In consideration of concentration, the arrangement of spot welding positions can be optimized.

  ADVANTAGE OF THE INVENTION According to this invention, the spot welding method, the spot welding apparatus, and the spot welding program which can relieve | moderate the stress concentration produced in the vicinity of a spot welding location and can aim at the intensity | strength improvement of a railway vehicle structure can be provided.

FIG. 1 is a diagram showing a spot welding system according to the present embodiment. FIG. 2A is a perspective view showing an appearance of a railway vehicle structure, and FIG. 2B is an exploded perspective view of side beams and a door frame. FIG. 3 is a flowchart for explaining a series of flows of the spot welding process according to the present embodiment. FIG. 4 is a diagram showing a spot layout in the vicinity of one end of the lower part of the door frame (web plate). FIG. 5 is a diagram illustrating a state in which the side beams and the door frame are subjected to indirect spot welding.

  Preferred embodiments of the present invention will be described with reference to the drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and a duplicate description is omitted.

  With reference to FIG. 1, the structure of the spot welding system 1 which concerns on this embodiment is demonstrated. The spot welding system 1 is a system for spot welding various members constituting a railway vehicle structure, and includes a spot welding apparatus 10 and a welding robot 20.

  The spot welding apparatus 10 is configured by a computer and controls the welding robot 20 to cause the welding robot 20 to spot weld two members. The spot welding apparatus 10 includes a data storage unit 11, a data processing unit 12, and a drive control unit 13.

  The data storage unit 11 includes various storage media such as a ROM, a RAM, and a hard disk. The data storage unit 11 stores a plurality of spot layout data (four spot layout data in the present embodiment), CAD data that models a railway vehicle structure, initial condition data, and a spot welding program according to the present embodiment. To do. As will be described in detail later, the spot layout data is position data indicating an array of planned positions for spot welding one member and another member constituting the railway vehicle structure.

  The data processing unit 12 is configured by a CPU. The data processing unit 12 calculates the stress at each scheduled position of spot welding based on the plurality of spot layout data stored in the data storage unit 11. The data processing unit 12 selects one spot layout data from a plurality of spot layout data based on the result of comparing the calculated magnitudes of the stresses. The data processing unit 12 generates two-dimensional coordinate data of an actual position where the welding robot 20 should spot weld the railway vehicle structure from each planned position of the selected spot layout data and CAD data modeling the railway vehicle structure. .

  The drive control unit 13 includes a CPU and a communication device. The drive control unit 13 outputs a signal to the welding robot 20 based on the two-dimensional coordinate data generated by the data processing unit 12 and controls the positioning operation and the welding operation of the welding robot 20. That is, the drive control unit 13 performs offline teaching of the welding robot 20.

  The welding robot 20 is a welding robot that performs spot welding by an indirect method. The welding robot 20 performs a positioning operation and a welding operation based on the signal received from the drive control unit 13. The welding robot 20 includes a main body 21, an actuator 22 for spot welding electrodes, an actuator 23 for contact electrodes, and a positioning actuator 24. The main body 21 transmits the signal received from the drive control unit 13 to the spot welding actuator 22, the contact gun actuator 23, and the positioning actuator 24.

  The spot welding electrode actuator 22 is attached to the side surface 21 a of the main body 21. The spot welding electrode actuator 22 can reciprocate in the direction of arrow A (Z direction, vertical direction) in FIG. 1 by an actuator (not shown) of the main body 21. Therefore, the main body 21 positions the spot welding electrode actuator 22 in the vertical direction.

  The spot welding electrode actuator 22 includes an air cylinder 22a (see FIG. 4) extending in the horizontal direction (Y direction) and a spot welding electrode 22b attached to the tip of the air cylinder 22a so as to protrude in the horizontal direction (Y direction). (See FIG. 4). The spot welding electrode 22b can be reciprocated in the arrow B direction (Y direction, horizontal direction) in FIG. 1 by the air cylinder 22a.

  The contact electrode actuator 23 is attached to the side surface 21 a of the main body 21. The contact electrode actuator 23 includes an air cylinder 23a (see FIG. 4) extending in the horizontal direction (Y direction) and a contact electrode 23b (attached to the tip of the air cylinder 23a so as to protrude upward in the vertical direction (Z direction). 4). The contact electrode 23b can reciprocate in the direction of arrow C (Z direction, vertical direction) in FIG. 1 by the air cylinder 23a.

  The positioning actuator 24 reciprocates the main body 21 in the arrow D direction (X direction, horizontal direction) in FIG. The positioning actuator 24 extends along the horizontal direction (X direction) so as to be orthogonal to the direction (Y direction) in which the spot welding electrode actuator 22 and the contact electrode actuator 23 extend. The positioning actuator 24 positions the main body 21 in the horizontal direction.

  Next, a method of spot welding various members constituting the railway vehicle structure by the spot welding system 1 will be described. As shown in FIG. 2 (a), the railway vehicle structure 30 includes a roof structure 31, a side structure 32, a frame 33, and a wife structure 34 that are joined to each other, and has a space for accommodating passengers. It has a box shape inside. The railway vehicle structure 30 is made of, for example, stainless steel.

  The side structure 32 is provided with door openings 35 alternately along the longitudinal direction. Around the door opening 35, an outer panel 36 constituting the outer surface of the railway vehicle is provided. A door frame 37 is provided on the peripheral edge of the door opening 35. A door 39 is installed at an entrance / exit 38 formed by the door opening 35 and the door frame member 37.

  In the following, as shown in FIG. 2B, a method of spot welding a side beam 33a, which is a part of the base frame 33, and a lower portion 37a of the door frame 37 (door frame lower portion 37a) using the spot welding system 1. This will be described as an example. The side beam 33a includes a rectangular web plate 33b extending along one direction and a pair of flange plates 33c provided integrally at both ends in the width direction of the web plate 33b. Therefore, the side beam 33a has a C-shaped cross section.

  The door frame lower portion 37a includes a rectangular web plate 37b extending along one direction, and a flange plate 37c integrally provided at one end in the width direction of the web plate 37b. Therefore, the door frame lower portion 37a has an L-shaped cross section. The flange plate 37c is located approximately at the center in the longitudinal direction of the web plate 37b. The length of the flange plate 37c is shorter than the length of the web plate 37b.

  Spot welding of the side beam 33a and the door frame lower portion 37a is performed in a state where the web plates 33b and 37b are in contact with each other and the flange plate 37c is placed on one flange plate 33c. In FIG. 2 (b), the circle drawn on the web plate 33b and the circle drawn on the web plate 37b are connected by a broken line because the web plate 33b, It shows that 37b is joined by spot welding.

  In spot welding, first, the data processing unit 12 of the spot welding apparatus 10 reads a spot welding program from the data storage unit 11 and starts spot welding processing. Next, the data processing unit 12 reads out CAD data obtained by modeling the side beam 33a and the door frame lower portion 37a and initial condition data from the data storage unit 11 (step S1 in FIG. 3).

  The initial condition data is the amount of displacement at both ends of the member model assuming that the side beam 33a and the door frame lower portion 37a are joined by spot welding. This amount of displacement is obtained based on the analysis result when the maximum vertical load is added to the overall model of the railway vehicle structure 30.

  Subsequently, the data processing unit 12 reads the first spot layout data from the data storage unit 11 (step S2 in FIG. 3). The first spot layout data is position data indicating a first arrangement of planned positions for spot welding the web plates 33b and 37b. As shown in FIG. 4A, the first array has two rows of scheduled positions for spot welding arranged in the longitudinal direction at predetermined intervals. When the position coordinates of the planned spot welding position are expressed in an (X, Z) orthogonal coordinate system, the first spot layout data is (1, 1), (1, 3), (3, 1), ( 3,3), (5,1), (5,3), (7,1), (7,3).

  Subsequently, the data processing unit 12 calculates the stress at each planned position based on the CAD data, the initial condition data, and the first spot layout data (step S3 in FIG. 3). Specifically, the data processing unit 12 is provided at both ends of the member model that is assumed to be joined by spot welding only at the side beam 33a and the door frame lower portion 37a at the planned position indicated by the first spot layout data. Then, the amount of displacement based on the initial condition data is set, and the von Mises stress distribution in the web plate 33b is calculated. Next, the data processing unit 12 acquires the magnitude of the von Mises stress at the coordinates of each planned position from the calculated stress distribution. Therefore, the data processing unit 12 obtains a set of coordinates and the magnitude of the von Mises stress (X coordinate, Z coordinate, stress value) as analysis data for each planned position.

  Subsequently, the data processing unit 12 determines whether or not analysis of all spot layout data has been completed (step S4 in FIG. 3). In the present embodiment, since the analysis of the second to fourth spot layout data has not been completed yet, the process returns to step S2, and the data processing unit 12 reads the second spot layout data from the data storage unit 11 (see FIG. 3 step S2), the stress is similarly analyzed (step S3 in FIG. 3). In the present embodiment, this process is repeated for the third and fourth spot layout data.

  The second spot layout data is position data indicating a second array of positions to be spot-welded between the web plates 33b and 37b. In the second array, as shown in FIG. 4B, spot welding positions are denser than the first array at the end of the web plate 37b, and in the vicinity of the corner of the web plate 37b. The planned spot welding position does not exist. When the position coordinates of the planned spot welding position are expressed in an (X, Z) orthogonal coordinate system, the second spot layout data is (1, 1), (2, 1), (2, 2), ( 3,1), (3,2), (3,3), (4,1), (4,2), (4,3), (5,1), (5,2), (5, 3), (7, 1), (7, 3).

  The third spot layout data is position data indicating a third array of positions where the web plates 33b and 37b are spot-welded. In the third arrangement, as shown in FIG. 4C, the spot welding positions are denser than the first arrangement at the end of the web plate 37b, but in the vicinity of the corner of the web plate 37b. There are fewer scheduled positions for spot welding than in the second array. When the position coordinates of the planned spot welding position are expressed in an (X, Z) orthogonal coordinate system, the third spot layout data is (1, 1), (2, 1), (3, 1), ( 3,2), (4,1), (4,2), (4,3), (5,1), (5,2), (5,3), (7,1), (7, 2) and (7, 3).

  The fourth spot layout data is position data indicating a fourth array of positions to be spot-welded between the web plates 33b and 37b. In the fourth arrangement, as shown in FIG. 4D, there is one row of scheduled spot welding positions arranged in the longitudinal direction at predetermined intervals. When the position coordinates of the planned spot welding position are expressed in an (X, Z) orthogonal coordinate system, the first spot layout data is (1, 1), (3, 1), (5, 1), ( 7, 1).

  Subsequently, the data processing unit 12 selects spot layout data having the smallest stress concentration from the first to fourth spot layout data based on each analysis data obtained for each planned position (step S5 in FIG. 3). ). For example, the maximum value of the von Mises stress obtained for each scheduled position of the first spot layout data and the magnitude of the von Mises stress obtained for each scheduled position of the second spot layout data The maximum value, the maximum value of the von Mises stress obtained for each planned position of the third spot layout data, and the magnitude of the von Mises stress obtained for each planned position of the fourth spot layout data The spot layout data having the smallest maximum value is selected by comparing with the maximum value.

  Subsequently, the data processing unit 12 generates two-dimensional coordinate data of an actual position at which the welding robot 20 should spot weld the railway vehicle structure from each planned position and CAD data of the selected spot layout data (FIG. 3). Step S6). Subsequently, the drive control unit 13 outputs a signal to the welding robot 20 based on the two-dimensional coordinate data generated by the data processing unit 12, controls the positioning operation and the welding operation of the welding robot 20, and controls the side beam 33a. Spot welding is performed with the door frame lower portion 37a (step S7 in FIG. 3).

  Specifically, the welding robot 20 uses the main body 21 and the positioning actuator 24 to position the spot welding electrode 22b in the XZ plane. Next, the welding robot 20 operates the air cylinders 22a and 23a to press the spot welding electrode 22b against the web plate 37b by the air cylinder 22a and the contact electrode 23b by the air cylinder 23a as shown in FIG. Press against the plate 33b. Next, the welding robot 20 applies a voltage between the electrodes 22b and 23b. Thereby, an electric current flows in order of the spot welding electrode 22b, the web board 37b, the web board 33b, the flange board 33c, and the contact electrode 23b, and the web boards 33b and 37b are joined.

  In the present embodiment as described above, the stress at each scheduled position is calculated for each of the plurality of spot layout data. Subsequently, one spot layout data is selected from a plurality of spot layout data based on the result of comparing the calculated magnitudes of the respective stresses. Specifically, for the first to fourth spot layout data, the maximum value of the magnitude of the von Mises stress obtained for each planned position is obtained, and the smallest value among these four maximum values is shown. Spot layout data is selected. By spot welding the side beam 33a and the door frame lower portion 37a in accordance with the selected spot layout data, it is possible to optimize the spot welding position arrangement in consideration of the stress concentration generated in the vicinity of the spot welding location. As a result, it is possible to alleviate the stress concentration generated in the vicinity of the spot welding location and improve the strength of the railway vehicle assembly 30.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments. For example, in the present embodiment, the method of spot welding the side beam 33a and the door frame lower portion 37a has been described. However, the present invention is not limited to this, and the present invention is applied to spot welding of various members constituting the railway vehicle structure 30. be able to. For example, the outer plate and the elongated member may be spot welded using the present invention. More specifically, for example, spot welding between the side outer plate and the reinforcing member or the bone member, spot welding between the roof member and the rafter member, and spot welding between the wife outer plate and the end beam or the reinforcing member can be mentioned. .

  The present invention can be widely applied to resistance spot welding and laser spot welding. As the resistance spot welding, for example, the direct method or the indirect method described in the present embodiment can be employed.

  In the present embodiment, the data processing unit 12 calculates the von Mises stress, but instead of this, a main stress or a shear stress may be calculated.

  In the present embodiment, the electrodes 22b and 23b are driven by the air cylinders 22a and 23a. However, the electrodes 22b and 23b may be driven using other driving means. Examples of other driving means include a combination of a servo motor and a ball screw, and a linear actuator. However, since the air cylinders 22a and 23a have a buffering action, it is preferable to perform spot welding using the air cylinders 22a and 23a because explosions hardly occur.

  The number of spot welding spots may be counted to determine whether or not the number of spot hits exceeds a predetermined threshold. If it does in this way, the exchange time by abrasion of each electrode 22b and 23b can be grasped | ascertained.

  Since the central part in the longitudinal direction of the railway vehicle structure 30 is most bent, in this embodiment in which the side beam 33a and the door frame lower part 37a are spot-welded, the side beam located near the center in the longitudinal direction of the railway vehicle structure 30. 33a and the door frame lower part 37a are preferably modeled.

  DESCRIPTION OF SYMBOLS 1 ... Spot welding system, 10 ... Spot welding apparatus, 11 ... Data storage part, 12 ... Data processing part, 13 ... Drive control part, 20 ... Welding robot, 30 ... Railroad vehicle structure, 33a ... Side beam, 37a ... Door frame beneath.

Claims (6)

A spot welding method in which a first member and a second member constituting a structure of a railway vehicle are joined by spot welding using a spot welding apparatus ,
The calculation means of the spot welding apparatus respectively show first to nth arrays (n is a natural number of 2 or more) of planned positions for spot welding the first member and the second member, respectively. a first step of calculating the stress at each planned position based on the n spot layout data;
One spot layout with a small stress concentration from the first to n-th spot layout data based on the result of the selection means of the spot welding apparatus comparing the magnitudes of the stresses calculated in the first step. A second step of selecting data;
According to a schedule position indicated by the selected spot layout data in the second step, and said second member and said first member have a third step of spot welding,
In the second step, the selection means of the spot welding apparatus sets the maximum value among the magnitudes of stresses at the respective planned positions of the m-th (m is a natural number of 1 to n) spot layout data. In the spot welding method , spot layout data indicating the minimum value among the m-th values is selected as the one spot layout data . 2. The spot welding method according to claim 1 , wherein the first member is a side beam constituting the structure, and the second member is a door frame constituting the structure. The spot welding method according to claim 1 , wherein the first member is an outer plate constituting the structure, and the second member is a long member constituting the structure. Wherein in the third step, the first to the member and the second member and the indirect spot welding, spot welding method according to any one of claim 1 to 3. A spot welding apparatus for controlling a welding robot that joins a first member and a second member constituting a structure of a railway vehicle by spot welding,
A memory for storing first to nth spot layout data respectively indicating first to nth (n is a natural number of 2 or more) arrangements of planned positions for spot welding the first member and the second member. Means,
Calculation means for calculating stresses at respective scheduled positions based on the first to n-th spot layout data stored in the storage means;
Selection means for selecting one spot layout data having a small stress concentration from the first to n-th spot layout data based on the result of comparing the magnitudes of the stresses calculated by the calculation means;
Control means for controlling the welding robot so as to spot weld the first member and the second member according to a planned position indicated by the spot layout data selected by the selection means ;
When the maximum value among the magnitudes of stresses at each predetermined position of the m-th spot layout data (m is a natural number of 1 to n) is the m-th value, A spot welding apparatus that selects spot layout data indicating a minimum value as the one spot layout data . A spot welding program for controlling a welding robot that joins a first member and a second member constituting a structure of a railway vehicle by spot welding,
Computer
Storage for storing first to n-th spot layout data respectively indicating first to n-th (n is a natural number of 2 or more) arrays of planned positions for spot welding of the first member and the second member. Means,
Calculation means for calculating stresses at respective scheduled positions based on the first to n-th spot layout data stored in the storage means;
Selection means for selecting one spot layout data having a small stress concentration from the first to n-th spot layout data based on the result of comparing the magnitudes of the stresses calculated by the calculation means;
According to the planned position indicated by the spot layout data selected by the selection means, the control means for controlling the welding robot so as to spot weld the first member and the second member,
When the maximum value among the magnitudes of stresses at each predetermined position of the m-th spot layout data (m is a natural number of 1 to n) is the m-th value, A spot welding program for selecting spot layout data indicating a minimum value as the one spot layout data .

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