JP2011110580A - Welding gun for capacitor discharge stud welding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding gun for capacitor discharge stud welding, a welding gun that facilitates adjustment of a pressurizing force for a stud and that also facilitates recording of pressure adjustment. <P>SOLUTION: The welding gun for capacitor discharge stud welding includes: a cylindrical body installed in a housing; a spring energizing the cylindrical body toward the tip end direction; and a connection conducting member that connects a welding cable from a welding capacitor of a welding power unit for making a welding current flow between a stud to be welded and a base material. The welding gun is configured to make a welding current flow between the base material and the stud through a chuck by the operation of a trigger switch and to perform welding by pressurizing the stud to the base material. The welding gun is characterized in that it has an adjustment means capable of adjusting a spring force to the stud of the cylindrical body by the spring and a control means capable of controllably operating the adjustment means in a manner making the spring force coincide with a preset target pressurizing force. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an improvement in a welding gun used for capacitor discharge type stud welding in which a stud is welded to a base material in a few thousandths of a second using the discharge energy of the capacitor.

Conventionally, in a welding gun for capacitor discharge type stud welding, manually adjusting the pressure of the stud against the base material has been performed.
FIG. 11 is a partial cross-sectional view of a conventional welding gun.
In the figure, reference numeral 100 denotes a cylindrical housing, and a cap 101 is detachably attached to the rear end of the housing 100. The housing 100 is provided with a handle 102, and the handle 102 is provided with a trigger button 103. A cylindrical body 104 made of a conductive material is supported inside the housing 100 by a bearing (not shown) so as to be slidable in the axial direction. A chuck 105 for attaching a stud is inserted at the tip of the cylindrical main body 104, and this chuck 105 is fixed to the cylindrical main body 104 by a tightening nut 106.
In the figure, reference numeral 107 denotes a connection terminal member for connecting a terminal 108 of a welding cable from a welding power source device (not shown) to the cylindrical main body 104.
Further, as shown in FIG. 11, the cylindrical main body 104 is provided with two spring seats 109 and 110, and the cylindrical main body 104 is disposed in the distal direction between the two spring seats 109 and 110. A spring 111 is provided for pressing toward the front. One of the two spring seats 109 is slidable in the axial direction along the cylindrical body 104 by a spring adjusting screw 112 screwed into the rear end of the housing 100, whereby the repulsive force of the spring 111, That is, it is comprised so that the pressurizing force with respect to a stud can be adjusted (refer patent document 1).

Japanese Utility Model Publication No. 61-82761

In the above-described conventional welding gun, after adjusting the spring adjusting screw 112 manually, it is necessary to repeatedly measure the pressure applied to the stud using a pressure measuring device or the like, so that an optimum pressure must be obtained. There is a problem that it takes time to adjust.
In addition, the spring adjustment screw 112 must be turned manually, and the cap 101 must be removed in order to turn the spring adjustment screw 112, so that there is a problem that the adjustment work is troublesome and complicated.
Above all, the conventional welding gun, as described above, is troublesome and complicated to adjust the applied pressure, and takes time and effort. Therefore, the stud material / size / shape, base material, base material surface treatment, sputtering The pressurizing force cannot be adjusted flexibly according to welding conditions such as tolerance level, presence / absence of anti-spatter adhesion, welding burn, welding distortion, quality control level, etc. There is a serious problem.
The present invention provides a welding gun for capacitor discharge type stud welding, which solves the above-mentioned conventional problems, makes it easy to adjust the pressure applied to the stud, and can easily record the pressure adjustment. The purpose is to do.

In order to achieve the above-described object, a welding gun for capacitor discharge type stud welding according to the present invention includes a chuck that is slidable along an axial direction in a housing and receives a stud to be welded at a tip. A welding cable from a welding capacitor of a welding power source device for flowing a welding current between a cylindrical main body, a spring for urging the cylindrical main body toward the distal end thereof, and a stud to be welded and a base material; A capacitor discharge having a connection energizing member to be connected, and configured to cause a welding current to flow between the base material and the stud via the chuck by the operation of a trigger switch, and press the stud against the base material for welding. In the welding gun for type stud welding, the adjusting means capable of adjusting the spring force of the cylindrical body against the stud of the cylindrical body, and the spring force is adjusted to a preset target pressure. Characterized in that a control means for controlling operation of said adjusting means.
In the first aspect, the adjustment of the spring force is performed by detecting means for detecting a pressing force applied to the stud of the cylindrical body by the spring, an actual pressing force obtained by the detecting means, and a preset target pressing force. And a control means for operating the adjusting means so as to match the actual applied pressure with the target applied pressure based on the comparison result.
In the second aspect, the adjustment of the spring force is performed by calculating a target deflection amount based on a spring constant of the spring from a preset target pressing force, and the adjusting means sets the actual deflection amount of the spring to the target deflection amount. Control means for operating the adjusting means to match.
Preferably, the spring is provided between a first spring seat provided at a rear end of the cylindrical main body and a second spring seat provided apart from the first spring seat in the axial direction. In this case, the second spring seat may be slidable in the axial direction inside the housing, and the adjusting means may be configured to adjust the position of the second spring seat.
The adjusting means may be, for example, a servo motor, a step motor, or an actuator incorporating these motors.
The measurement of the applied pressure by the detection means may be, for example, a pressure sensor disposed between the spring and the cylindrical main body, or a separate load measuring instrument.

  A welding gun for capacitor discharge type stud welding according to the present invention includes an adjusting means capable of adjusting a spring force, and a control means for controlling and operating the adjusting means so as to match the spring force with a preset target pressurizing force. It is possible to automatically adjust the pressure applied to the welding gun's stud to the target pressure, so that the stud material / size / shape, base material, base material surface treatment, spatter output, etc. According to the welding conditions such as tolerance, presence / absence of anti-spattering liquid, welding burn, welding distortion, quality control level, etc., the pressure can be adjusted flexibly. There is an effect. Also, by recording the control log by the control means, it is possible to easily keep the adjustment record of the applied pressure, so it is easy to manage which stud was welded with what applied pressure after performing stud welding. Will be able to.

It is a fragmentary sectional view of the 1st example of the welding gun concerning the present invention. 3 is a schematic block diagram showing the relationship between the constituent members of the welding gun of the first embodiment and the control device 17. FIG. It is a flowchart which shows the example of the control method which adjusts a pressurizing force every time the stud of a 1st Example is welded. It is a schematic block diagram equivalent to FIG. 2 which shows the 2nd Example of the welding gun which concerns on this invention. It is a flowchart which shows the example of the control method which adjusts a pressurizing force beforehand before welding the stud of a 2nd Example. It is a schematic block diagram equivalent to FIG. 2 which shows the 3rd Example of the welding gun which concerns on this invention. It is a flowchart which shows the example of the control method which adjusts a pressurizing force beforehand before welding the stud of a 3rd Example. (A) And (b) is a figure which shows the specific example of the load measuring device 25 separate from a welding gun. It is a fragmentary sectional view corresponding to Drawing 1 showing the 4th example of the welding gun concerning the present invention. It is a fragmentary sectional view corresponding to Drawing 1 showing the 5th example of the welding gun concerning the present invention. It is a fragmentary sectional view of the conventional welding gun.

  Several embodiments of a welding gun for capacitor discharge stud welding (hereinafter simply referred to as a welding gun) according to the present invention will be described below with reference to one embodiment shown in the accompanying drawings.

FIG. 1 is a partial cross-sectional view of a welding gun according to the present invention.
This welding gun is a contact-type welding gun that discharges a steel stud or a brass stud when the stud tip is pressed against a base material.
Reference numeral 1 denotes a cylindrical housing, and a cap 2 is detachably attached to the rear end of the housing 1. The housing 1 is provided with a handle 3, and the handle 3 is provided with a trigger button 4. A cylindrical body 5 made of a conductive material is supported inside the housing 1 so as to be slidable in the axial direction by a bearing (not shown). A chuck 6 for attaching a stud S is inserted at the tip of the cylindrical main body 5, and this chuck 6 is fixed to the cylindrical main body 5 by a tightening nut 7. In the figure, reference numeral 8 denotes a leg provided at the tip of the cylindrical housing 1.
In FIG. 1, reference numeral 9 denotes a connection terminal member for connecting a terminal 10 of a welding cable from a welding power source device (not shown) to the cylindrical main body 5. This connection terminal member is not necessarily arranged in the cylindrical housing 1 as shown in the figure. You may make it fit the terminal of the welding cable from a welding power supply device behind the said chuck | zipper 6. FIG. A welding gun having such a configuration is known as an FG12 type welding gun which is the product of the present applicant.
Further, as shown in FIG. 1, two spring seats 11 and 12 are provided inside the housing 1, and the cylindrical main body 5 faces the distal direction between the two spring seats 11 and 12. A spring 13 is provided for pressing. One of the two spring seats (first spring seat) 11 is fixed to the upper end of the cylindrical body 5, and the other spring seat (second spring seat) 12 is axially attached to the housing 1. Are slidably provided. A motor 14 is provided above the second spring seat 12 in the housing 1. A screw thread is formed on the output shaft 14a of the motor 14, and a nut 15 that is spline-engaged with the housing 1 is engaged with the output shaft 14a. The second spring seat 12 is fixed to the bottom surface of the nut 15. With this configuration, when the motor 14 is driven, the nut 15 meshed with the output shaft 14a moves in the axial direction in the housing 1 in accordance with the rotation direction of the output shaft 14a. The pressure applied to the cylindrical body 5 of the spring 13 is changed by moving in the direction. Reference numeral 14b denotes a control line connected to the control device 17 described later through the handle 3. The operation of the motor 14 is controlled by the control device 17 in steps described later.
Further, a pressure sensor 16 is provided between the first spring seat 11 and the spring 13. An output line 16 a of the pressure sensor 16 is connected to the control device 17 through the handle 3.
The welding gun configured as described above further includes a separate control device 17.
FIG. 2 is a schematic block diagram showing the relationship between the components of the welding gun and the control device 17.
As shown in FIG. 2, the control device 17 includes a motor drive unit 17 a, a pressure comparison unit 17 b, and a welding condition setting unit 17 c, and the pressure comparison unit 17 b is measured pressure data detected by the pressure sensor 16. And the set pressure data set by the welding condition setting unit 17c are compared, these data are compared, and the motor 14 is driven via the motor drive unit 17a so as to match the measured pressure to the set pressure. Let

FIG. 3 is a flowchart showing an example of a control method for adjusting the applied pressure every time the stud is welded using the welding gun configured as described above.
As shown in the drawing, first, a welding pressure setting program is called in the welding condition setting unit 17c (S1-1),
Next, a welding condition is called using a pressure setting program (S1-2), and a set pressure is called based on the called welding condition (S1-3).
In addition, the optimal setting pressurization according to various welding conditions is memorize | stored in the welding condition setting part 17c previously.
After the calling of the set pressure is completed, the stud S is set on the chuck 6 of the welding gun and the welding gun is pressed against the base material (S1-4). As shown in FIG. 1, since the stud protrudes forward from the leg portion, when the welding gun is pressed against the base material, the cylindrical body 5 is pushed upward against the urging force of the spring 13.
When the user presses the trigger button 4 of the handle 3 in this state, the welding trigger is turned on (S1-5), and the setting of the applied pressure and the welding process are started.
When the setting of the applied pressure and the welding process are started, the applied pressure comparing unit 17b inputs the applied pressure detected by the pressure sensor 16 (S1-6), and compares the set applied pressure called in S1-3. (S1-7) If the detected measured pressure is different from the set pressure, the motor 14 is driven via the motor drive unit 17a so that the measured pressure is equal to the set pressure. Specifically, when the measured applied pressure is lower than the set applied pressure, the motor 14 is driven so that the second spring seat 12 is lowered, and conversely, when the measured applied pressure is higher than the set applied pressure, The motor 14 is driven so that the spring seat 12 is raised (S1-8).
The above-described processes of S1-6 to S1-8 are repeated until the actually measured pressurizing force becomes equal to the set pressurizing force. When the actually measured pressurizing force becomes equal to the set pressurizing force, the motor 14 is stopped (S1-9). The actual measured pressurizing force is recorded on any recording means together with the welding conditions (preferably including identification information of the stud to be welded, for example, information such as “how many studs”) (S1-10).
Next, the welding signal is turned on (S1-11), and welding is performed by passing a current from the welding power source 18 to the cylindrical main body 5 (S1-12).
When the next stud is to be welded after welding, the process returns to S1-4, the next stud is set on the chuck 6 of the welding gun, and the welding gun is pressed against the base material (S1-13). .
In this embodiment, the pressure can be adjusted every time the stud S is welded. Therefore, when the lengths of the studs having the same diameter are different, that is, the protrusion of the stud S from the leg portion 8 in FIG. 1 is different. Even in this case, the pressure can be automatically adjusted to the same value. Further, in the case of different stud diameter sizes, a pressing force corresponding to each stud diameter size is automatically obtained.
In the above, the control method for adjusting the applied pressure every time the stud S is welded has been described. However, when the same size stud is continuously welded, the applied pressure is adjusted only once. May be programmed. Further, the drive switch of the motor 14 can be provided separately from the welding trigger button 4 as indicated by reference numeral 14c in FIG.

Next, a second embodiment of the welding gun according to the present invention will be described.
FIG. 4 is a schematic block diagram corresponding to FIG. 2 showing a second embodiment of the welding gun according to the present invention.
Since the construction of the welding gun is the same as that of the embodiment shown in FIG. 1 except that the pressure sensor 16 is not provided, the same or corresponding components are denoted by the same reference numerals and detailed description thereof will not be given. Omitted.
The control device 20 includes a motor drive unit 20a that controls the operation of the motor 14, and the upper end position of the spring when the stud S is pressed against the base material (usually, the spring 13 when the welding gun described later is pressed against the base material. A reference position storage unit 20b for storing a free end position of the motor 14), an output shaft movement amount calculation unit 20c for calculating a movement amount of the output shaft 14a of the motor 14 by the motor driving unit 20a, and a predetermined pressurizing force. Are provided with a welding condition setting unit 20d for calculating a set deflection amount of the spring 13 and a deflection amount comparison unit 20e.
In the control device 20 configured as described above, in the deflection amount comparison unit 20e, an actual measurement value of the deflection amount of the spring 13 based on the movement amount of the output shaft 14a of the motor 14 calculated by the output shaft movement amount calculation unit 20c. And the calculated actual deflection amount is compared with the set deflection amount calculated by the welding condition setting unit 20d, and the motor 14 is driven via the motor driving unit 20a so as to match the actual deflection amount with the set deflection amount. As a result, a predetermined pressure is obtained.

FIG. 5 is a flowchart showing an example of a control method in which the pressure is adjusted in advance before the stud is welded, using the welding gun configured as described above.
As shown in the drawing, first, a welding pressure setting program is called in the welding condition setting unit 20d (S2-1).
Next, the spring constant k of the spring 13 used in the welding gun previously measured with a spring testing machine is input. Once the input is set, no further input is required unless the spring 13 is replaced (S2-2).
Thereafter, the welding condition is called using the pressure setting program (S2-3), and the set pressure data P is called based on the called welding condition (S2-4).
Next, based on the set pressure data P called in S2-4 and the spring constant k inputted in S2-2, a set deflection amount for obtaining a predetermined pressure P is calculated using the following equation ( S2-5).
Set deflection = Set pressure P / Spring constant k
After calculating the set deflection amount, the stud S is set on the chuck 6 of the welding gun, and the welding gun is pressed against the base material (S2-6). Similar to the welding gun shown in FIG. 1, since the stud protrudes forward from the leg portion, when the welding gun is pressed against the base material, the cylindrical main body 5 is pushed upward against the biasing force of the spring 13. .
When the user presses the trigger button 4 of the handle 3 in this state, the trigger of the motor 14 is turned ON (S2-7), and the pressure setting process is started.
When the pressing force setting process is started, the output shaft movement amount calculation unit 20c calculates the movement amount of the output shaft 14a of the motor 14 by the motor driving unit 20a from the reference position of the spring 13 stored in the reference position storage unit 20b. In step S2-8, the deflection amount comparison unit 20e calculates an actual measurement value of the deflection amount of the spring 13 based on the movement amount of the output shaft 14a of the motor 14 calculated by the output shaft movement amount calculation unit 20c. The calculated actual deflection amount is compared with the set deflection amount calculated by the welding condition setting unit 20d (S2-9). When the measured actual deflection amount is different from the set deflection amount, the motor driving unit 17a is used. Then, the motor 14 is driven so that the actually measured deflection amount becomes equal to the set deflection amount. Specifically, when the actual deflection amount is lower than the set deflection amount, the motor 14 is driven so that the second spring seat 12 is lowered. Conversely, when the actual deflection amount is higher than the set deflection amount, The motor 14 is driven so that the spring seat 12 is raised (S2-10).
The above-described processing of S2-8 to S2-10 is repeated until the actually measured deflection amount becomes equal to the set deflection amount. When the actually measured deflection amount becomes equal to the set deflection amount, the motor 14 is stopped (S2-11). The actual measured deflection amount is recorded in an arbitrary recording means together with the welding conditions (S2-12), and the pressurizing force setting program is terminated (S2-13).
In this embodiment, no welding pressure measuring device is required, so that the welding gun has a simple structure. In particular, the welding gun is useful in a work site where the applied pressure is of a quality control level that does not require measurement recording for each welding of the stud S or when the number of stud sizes to be welded is limited to several types.
If the adjusting means is an actuator with a built-in servo motor and step motor, it is advantageous that the movement amount in the axial direction can be easily controlled.
In this embodiment, it is advantageous to make the protrusion of the stud S from the leg portion 8 constant regardless of the length of the stud. For this purpose, the stud S mounting portion of the chuck 6 is stepped or bottomed, and the rear end portion of the stud S is brought into contact with the stepped (bottomed) portion to serve as a stopper. The depth to the stepped (bottomed) portion is made to correspond to the length of the stud S, so that the protrusion of the stud is made constant. As another method, the chuck 6 may be left as it is, and the length of the leg portion 8 may be changed according to the length of the stud S.
The positioning of the reference position can be performed according to the following procedure when the above-described stud S has a fixed allowance.
(1) The distance from the initial position of the first spring seat 11 (the frontmost end position on the stud side) to the position where the second spring seat 12 is most retracted in the direction opposite to the stud S by the motor 14 (the rearmost position) is welding. It is decided by the design of the gun.
(2) The spring length is added to the position when the stud S is pressed against the base material from the initial position of the first spring seat 11. This position is set as the reference position.
(3) This determines the distance from the rearmost position of the second spring seat 12 to the reference position.
(4) A value obtained by adding the amount of deflection to this distance is the amount of movement (movement position) of the second spring seat 12.
The distance from the rearmost end position of the second spring seat 12 to the reference position may be input / output to / from the control device 20, and fixed values such as positions and spring lengths in (1) and (2) are input in advance. In addition, other values may be calculated by the control device 20.
The reference position of the spring 13 is adjusted and stored when the welding gun is shipped, so that it can be used immediately at the work site.
It is also possible to incorporate both the present embodiment and the first embodiment, and in this case, there is an advantage that it is possible to flexibly cope with both cases where the quality control level of welding is high and low.
It should be noted that it is possible to freely set the applied pressure regardless of the length of the stud S and regardless of the chuck to be used only in this embodiment. In this case, a position measuring device such as a potentiometer or a displacement meter is attached to the front surface of the first spring seat 11 from the front end side of the housing 1, and data is sent to the control device 20. That is, the position (the position before adding the spring length in (2) above) when the stud S in the above case is pressed against the base material is measured by the position measuring device, and this is sent to the control device 20 for calculation. It will be understood from the above that this can be done.

Next, a third embodiment of the welding gun according to the present invention will be described.
FIG. 6 is a schematic block diagram corresponding to FIG. 2 showing a third embodiment of the welding gun according to the present invention.
Since the construction of the welding gun is the same as that of the embodiment shown in FIG. 1 except that the pressure sensor 16 is not provided, the same or corresponding components are denoted by the same reference numerals and detailed description thereof will not be given. Omitted.
In this third embodiment, the welding gun is provided with a separate load measuring device 25 outside.
As shown in FIG. 6, the control device 26 includes a motor driving unit 26 a, a pressure comparison unit 26 b, and a welding condition setting unit 26 c, and the pressure comparison unit 26 b is measured pressure data detected by the load measuring instrument 25. And the set pressure data set by the welding condition setting unit 26c are compared, these data are compared, and the motor 14 is driven via the motor drive unit 26a so as to match the measured pressure to the set pressure. Let

FIG. 7 is a flowchart showing an example of a control method in which the pressure is adjusted in advance before the stud is welded by using the welding gun configured as described above.
As shown in the drawing, first, a welding pressure setting program is called in the welding condition setting unit 20c (S3-1),
Next, a welding condition is called using a pressure setting program (S3-2), and a set pressure is called based on the called welding condition (S3-3).
The welding condition setting unit 26c stores in advance optimum set pressures according to various welding conditions.
After the calling of the set pressure is completed, the stud S is set on the chuck 6 of the welding gun, and the welding gun is pressed against the measurement surface of the load measuring instrument 25 (S3-4). As in the embodiment shown in FIG. 1, since the stud protrudes forward from the leg portion, when the welding gun is pressed against the measurement surface of the load measuring instrument 25, the cylindrical body 5 resists the urging force of the spring 13. Is pushed upward.
When the user presses the trigger button 4 of the handle 3 in this state, the welding trigger is turned on (S3-5), and the setting of the applied pressure is started.
When the pressure setting process is started, the pressure comparison unit 26b inputs the pressure detected by the load measuring instrument 25 (S3-6), and compares it with the set pressure called in S3-3. (S3-7) When the detected actual pressurization is different from the set pressurization, the motor 14 is driven via the motor drive unit 26a so that the actual pressurization becomes equal to the set pressurization. Specifically, when the measured applied pressure is lower than the set applied pressure, the motor 14 is driven so that the second spring seat 12 is lowered, and conversely, when the measured applied pressure is higher than the set applied pressure, The motor 14 is driven so that the spring seat 12 is raised (S3-8).
The above-described processes of S3-6 to S3-8 are repeated until the actually measured pressurizing force becomes equal to the set pressurizing force. When the actually measured pressurizing force becomes equal to the set pressurizing force, the motor 14 is stopped (S3-9). The actual measured pressure is recorded in an arbitrary recording means together with the welding conditions (S3-10), and the pressure setting process is terminated (S3-11).

FIGS. 8A and 8B are diagrams showing a specific example of the load measuring instrument 25 that is separate from the welding gun. The load measuring instrument 25 may be completely independent as shown in FIG. 8A, and is incorporated in the welding power source device and / or the control device as shown in FIG. 8B. Also good.
As described above, in this embodiment, since it is not necessary to incorporate a pressure sensor in the welding gun body, a simple welding gun structure is obtained. Also, as in the second embodiment, the welding gun is useful at the work site when the applied pressure is of a quality control level that does not require measurement recording every time the stud S is welded or when the number of stud sizes to be welded is limited to several types. It becomes.

FIG. 9 is a partial cross-sectional view corresponding to FIG. 1 showing a fourth embodiment of the welding gun according to the present invention. The welding gun according to the fourth embodiment is a gap type welding gun that performs pressure welding discharge in a state where the base material is separated from the stud tip when welding an aluminum stud, a titanium stud, or the like. A solenoid coil 30 for pulling up and holding the cylindrical main body 5 is provided inside the cylindrical housing 1.
Since the welding gun according to the fourth embodiment is the same as the welding gun according to the first embodiment shown in FIG. 1 except for the gap system, the same or corresponding components are the same. Detailed description will be omitted. Further, the welding gun according to the fourth embodiment has the same configuration as that of the control device shown in FIG. 2 for the control device, and therefore, detailed description thereof is omitted here and shown in FIG. 2 as necessary. The description will be made using the same reference numerals as those of the control device 17.
FIG. 9A shows a state before the cylindrical main body 5 is pulled up, and FIG. 9B shows a state in which the cylindrical main body 5 is pulled up and held by exciting the solenoid coil 30. Before the stud S is pulled up in FIG. 9A, the stud S protrudes from the leg 8 when the stud S is mounted on the chuck 6 as in the first embodiment.
In the state where the cylindrical main body 5 is pulled up to the state shown in FIG. Drive.
This embodiment is different from the first embodiment in that the pressing force of the spring 13 is adjusted in a state in which the cylindrical main body 5 is pulled up and held. In addition to the application of the first embodiment described and illustrated herein, It is obvious that the present invention can be applied to the method of controlling the deflection amount of the second embodiment.
At the time of welding, when the trigger button 4 is operated, the excitation of the solenoid coil 30 is released, the spring 13 is released, pressurizing the stud S to the base material, and discharging energy from the capacitor.

FIG. 10 is a partial sectional view corresponding to FIG. 1 showing a fifth embodiment of the welding gun according to the present invention. Since the welding gun according to the fifth embodiment has the same configuration as the welding gun shown in FIG. 1 except for the configuration of the drive mechanism of the second spring seat 12, the same or corresponding components are denoted by the same reference numerals. Detailed description will be omitted.
In the fifth embodiment, the motor 35 is provided inside a case 36 fixed to the housing 1. A gear 35 b is provided on the output shaft 35 a of the motor 35.
A drive shaft 37 is rotatably provided inside the housing 1, and a nut 38 that is spline-engaged with the housing 1 is engaged with the drive shaft 37. A gear 37 a is formed integrally with the drive shaft 37, and the gear 37 a meshes with a gear 35 b provided on the output shaft 35 a of the motor 35.
The second spring seat 12 is fixed to the bottom surface of the nut 38. With this configuration, when the motor 35 is driven, the drive shaft 37 rotates through the gear 35b and the gear 37a, and the nut 38 moves in the axial direction in the housing 1 according to the rotation direction of the drive shaft 37. Accordingly, the second spring seat 12 moves in the axial direction to change the pressure applied to the tubular body 5 by the spring 13.
In the present embodiment, since the motor 35 in the case 36 is installed in parallel with the spring 13 in the housing, it can be provided as a useful welding gun at a welding location where the length of the welding gun is limited.
In addition to the application of the first embodiment described and illustrated herein, the present embodiment is obviously applicable to the systems of the second embodiment, the third embodiment, and the fourth embodiment. .

S Stud

DESCRIPTION OF SYMBOLS 1 Cylindrical housing 2 Cap 3 Handle 4 Trigger button 5 Cylindrical main body 6 Chuck 7 Tightening nut 8 Leg 9 Connection terminal member 10 Welding cable terminal 11 First spring seat 12 Second spring seat 13 Spring 14 Motor 14a Output shaft 14b Control line 14c Drive switch (example provided separately from welding trigger button 4)
DESCRIPTION OF SYMBOLS 15 Nut 16 Pressure sensor 16a Output line 17 Control apparatus 17a Motor drive part 17b Applied pressure comparison part 17c Welding condition setting part 18 Welding power supply device

20 control device 20a motor drive unit 20b reference position storage unit 20c output shaft movement amount calculation unit 20d welding condition setting unit 20e deflection amount comparison unit

25 Load measuring device 26 Control device 26a Motor drive unit 26b Pressure comparison unit 26c Welding condition setting unit

30 Solenoid coil

35 Motor 35a Output shaft 35b Gear 36 Case 37 Drive shaft 37a Gear 38 Nut

DESCRIPTION OF SYMBOLS 100 Cylindrical housing 101 Cap 102 Handle 103 Trigger button 104 Tubular main body 105 Chuck 106 Tightening nut 107 Connection terminal member 108 Terminal of welding cable 109 Spring seat 110 Spring seat 111 Spring 112 Spring adjustment screw

Claims (11)

A cylindrical main body having a chuck that is slidable along the axial direction in the housing and receives a stud to be welded to the tip;
A spring that urges the cylindrical body toward its distal end;
A connection energization member for connecting a welding cable from a welding capacitor of a welding power source device for flowing a welding current between a stud to be welded and a base material;
In a welding gun for capacitor discharge type stud welding configured to flow a welding current between the base material and the stud via the chuck by the operation of the trigger switch and press the stud against the base material for welding,
An adjusting means capable of adjusting a spring force against the stud of the cylindrical body by the spring;
And a control means for controlling and operating the adjusting means so as to match the spring force with a preset target pressing force. A welding gun for capacitor discharge type stud welding. A detecting means for detecting a pressure applied to the stud of the cylindrical main body by the spring;
The control means compares the actual pressure obtained by the detection means with the preset target pressure, and adjusts the actual pressure to the target pressure based on the comparison result. The welding gun for capacitor discharge type stud welding according to claim 1, wherein the spring force is adjusted by operating the adjusting means. The welding gun for capacitor discharge type stud welding according to claim 2, wherein the pressure detection means is a pressure sensor disposed between the spring and the cylindrical main body. The welding gun for capacitor discharge type stud welding according to claim 2, wherein the pressure detection means comprises a separate load measuring instrument. The control means is
The target deflection amount is calculated from the preset target pressure by the spring constant of the spring, and
Based on the amount of adjustment by the adjusting means, the actual amount of deflection of the spring is calculated,
By comparing the actual deflection amount of the spring and the target deflection amount, and operating the adjusting means to match the actual deflection amount of the spring with the target deflection amount based on the comparison result, the spring The welding gun for capacitor discharge type stud welding according to claim 1, wherein the force is adjusted. The welding gun for capacitor discharge type stud welding according to any one of claims 1 to 5, wherein the welding gun is a contact type in which discharge is performed in a state in which a stud tip is pressed against a base material. The welding gun for capacitor discharge type stud welding according to any one of claims 1 to 5, wherein the welding gun is a gap type in which pressure discharge is performed in a state in which a base material is separated from a stud tip. The spring is provided between a first spring seat provided at a rear end of the cylindrical main body and a second spring seat provided apart from the first spring seat in the axial direction;
The second spring seat is slidable axially within the housing;
The welding gun for capacitor discharge type stud welding according to any one of claims 1 to 7, wherein the adjusting means is configured to be capable of adjusting a position of the second spring seat. The welding gun for capacitor discharge type stud welding according to any one of claims 1 to 8, wherein the adjusting means is a servo motor, a step motor, or an actuator incorporating these motors. The welding gun for capacitor discharge type stud welding according to any one of claims 1 to 9, wherein the adjusting means is provided on the same line as the axis of the spring. The welding gun for capacitor discharge type stud welding according to any one of claims 1 to 9, wherein the adjusting means is provided in parallel with the axis of the spring.

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