JP2010207903A - Welding machine and welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding machine which can shorten time for making a welding electrode touch a workpiece to be welded and which, in addition, can make the welding electrode touch the workpiece softly. <P>SOLUTION: The welding machine is equipped with a hydraulic cylinder 17 and a pneumatic cylinder 23 which are connected to each other in series. One of the cylinders is fixed and the other cylinder is fixed to the piston rod of one cylinder, and the welding electrode 9 is fixed to the piston rod of the other cylinder. The pneumatic cylinder 23 has a shorter stroke than the hydraulic cylinder 17. The hydraulic cylinder 17 advances the hydraulic piston rod 17A so as to advance the welding electrode 9 until the interval between the welding electrode 9 and the workpiece to be welded comes to a prescribed distance. When the welding electrode 9 touches the workpiece to be welded, the pneumatic cylinder 23 gives pressing force to the workpiece to be welded via the pneumatic piston rod 23A. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a welding apparatus and a welding method having a mechanism for moving a welding electrode forward or backward by a combination of cylinders.

  Various methods have been proposed for joining the same kind of metal materials or different kinds of metals such as iron-based materials and copper materials. As one of the welding methods, capacitor type welding in which resistance welding or diffusion bonding is performed in a short time by discharging the electric charge charged in the capacitor instantaneously and causing a current having a large peak value to flow through the workpiece is widely known. Yes. In particular, when the objects to be welded made of different metal materials are diffusion-bonded together, a welding current having a large peak value is allowed to flow in a short time, and when the objects to be welded are plastically fluidized by energization of the welding current It is preferable that the welding electrode responds at a high speed to pressurize between the workpieces, and the plastic fluidized portion of the workpiece is submerged at a high speed (see, for example, Patent Document 1).

  Further, ring mash welding for joining the same kind of metal materials or different kinds of metals is also known (see, for example, Patent Document 2). According to this method, welding strength is relatively easily obtained by plastically fluidizing and pushing a part of the other workpiece into the plastic fluidized portion in the vicinity of the hole formed in one workpiece. In addition, a welded article having an excellent weld appearance can be obtained. Also in this ring mash welding, when the workpiece is plastically fluidized, the welding electrode responds at high speed and pressurizes between the workpieces, and the plastic fluidized part of one workpiece is the other workpiece It is preferable to sink into the hole portion at a high speed.

  Conventionally, a hydraulic cylinder or a pneumatic cylinder has been used as a pressurizing mechanism of a welding apparatus, but a hydraulic cylinder is inferior to a pneumatic cylinder in terms of responsiveness during welding, and a pneumatic cylinder is When the volume of the pressure vessel (cylinder casing) exceeds a predetermined value, it is subject to legal restrictions. When the design pressure is P and the volume of the pressure vessel is V, the product PV value is predetermined. These containers are subject to stricter regulations. Therefore, in the conventional case, a hydraulic cylinder or an air hydraulic cylinder (for example, see Patent Document 3) whose responsiveness is improved by using air pressure is often used. Pneumatic cylinders are used when the pressure vessel can be made to a small volume that is not subject to legal restrictions because the applied pressure is small, or the maximum distance between welding electrodes is narrow due to the small height of the workpiece. This is the case when the length of the pressure cylinder, in other words, the stroke is small and the pressure vessel has a small volume that is not subject to legal regulations.

JP 2007-190569 A JP 2004-017048 A JP 05-272507 A

  However, when the pneumatic cylinder disclosed in Patent Document 3 is used, the speed of the forward and backward movement of the welding electrode is improved, but since the impact when the welding electrode comes into contact with the work piece is large, it is moderate. If it is going to contact, the forward speed of a welding electrode must be restrict | limited, and it is difficult to improve the responsiveness after a welding electrode contacts a to-be-welded object as a pneumatic cylinder. That is, when the welded part of the work piece is plastically fluidized or melted during welding, the air hydraulic cylinder can respond at high speed following the plastic fluidization or melting of the welded part of the work piece from the aspect of control. There was a problem that I could not. For this reason, there has been a problem that sufficient welding quality cannot be obtained particularly in the above-described diffusion bonding of dissimilar metals or ring mash welding.

  Therefore, in order to solve the above-mentioned problems, the present invention combines separate hydraulic cylinders and pneumatic cylinders in series, and the hydraulic cylinders mainly share the advance distance and the retract distance of the welding electrode, and The pressure cylinder mainly performs the function of applying pressure to the welding electrode. In this way, even if the work piece is high, it can be advanced to the maximum stroke without limiting the speed of the forward movement of the welding electrode by the hydraulic piston rod of the hydraulic cylinder. When the pneumatic piston rod moves forward at a low speed over a short distance, the impact when the welding electrode comes into contact with the work piece can be reduced, and the soft contact can be achieved. Following up, the welding electrode can be made to respond at high speed.

  According to a first aspect of the present invention, there is provided a hydraulic cylinder fixed to a fixed object, and a pneumatic type fixed to a hydraulic piston rod of the hydraulic cylinder and advanced or retracted together as the hydraulic piston rod moves forward or backward. The pneumatic cylinder has a structure in which the length in the forward or backward direction is shorter than that of the hydraulic cylinder, and the pneumatic cylinder moves forward at a speed slower than the forward speed of the hydraulic piston rod. A pressure piston rod, and the second welding electrode or the first welding electrode is fixed to the pneumatic piston rod of the pneumatic cylinder, and the hydraulic cylinder is initially separated from the workpiece. The first or second welding electrode fixed to the pneumatic piston rod is advanced until the distance between the welding electrode at the position and the workpiece to be welded approaches a predetermined distance. When the welding electrode and the workpiece are in contact with each other, the cylinder applies pressure to the workpiece through the pneumatic piston rod, and the pneumatic cylinder applies pressure to the workpiece. The welding is performed by passing a welding current between the pair of welding electrodes.

  Therefore, according to the first invention, since the hydraulic piston rod only moves forward and backward by a predetermined maximum stroke, the hydraulic piston rod can be operated at a high speed, and the pneumatic piston rod slowly moves over a short distance. Since the welding electrode and the work piece are brought into contact with each other, the welding electrode can be advanced in a short time, but the welding electrode can be softly applied to the work piece without impacting the work piece. Can be contacted. Further, since separate hydraulic cylinders and pneumatic cylinders are coupled in series, the cross-sectional area of the surface perpendicular to the forward direction can be arbitrarily designed for both pressure vessels.

  According to a second aspect of the present invention, there is provided a power source for passing a welding current between the first welding electrode and the second welding electrode, and a plurality of objects to be welded are sandwiched between a pair of the welding electrodes from the power source. In a welding apparatus for energizing and welding a welded object, a pneumatic cylinder fixed to a fixed object, and a pneumatic piston rod of the pneumatic cylinder fixed to the pneumatic piston rod as the pneumatic piston rod moves forward or backward. A hydraulic cylinder that moves forward or backward together, and the pneumatic cylinder has a shorter length in the forward or backward direction than the hydraulic cylinder, and the hydraulic piston of the hydraulic cylinder A pneumatic piston rod that moves forward at a speed slower than the forward speed of the rod; the second welding electrode or the first welding electrode is fixed to the hydraulic piston rod; and the hydraulic cylinder is Initially, the hydraulic piston rod is advanced until the distance between the welding electrode at a position away from the workpiece and the workpiece is close to a predetermined distance, and the pneumatic cylinder is When the piston rod is advanced to advance the second welding electrode or the first welding electrode fixed to the hydraulic cylinder and the hydraulic piston rod, and the welding electrode and the workpiece are in contact with each other, A pressure is applied to the workpiece through a pneumatic piston rod and the hydraulic cylinder, and when the pneumatic cylinder applies pressure to the workpiece, the power source is connected between the pair of welding electrodes. The welding object is welded by applying a welding current to the welding object. Therefore, according to the second invention, the same effect as that of the first invention can be obtained, and the pneumatic cylinder that is likely to become a pressure vessel having a large diameter is fixed, and the hydraulic cylinder is moved forward and backward. As a result, the lateral shake can be reduced, the overall configuration can be simplified, and the cost can be reduced.

  According to a third invention, in the first invention or the second invention, the maximum stroke of the hydraulic piston rod is initially at a position distant from the workpiece, the welding electrode, and the workpiece Since the maximum distance between them is 80% or more and the maximum stroke of the pneumatic piston rod is 20% or less of the maximum distance, the internal volume of the pneumatic cylinder can be reduced. Therefore, since the hydraulic piston rod can be operated at a high speed and the pneumatic piston rod can be advanced at a low speed, it is possible to advance the welding electrode in a short time while giving an impact to the work piece. The welding electrode can be softly brought into contact with the workpiece.

  According to a fourth invention, in any one of the first invention to the third invention, the pneumatic cylinder has a first pressure chamber and a second pressure chamber separated by a piston. Compared with the first pipe connected to the first pressure chamber, the second pipe connected to the second pressure chamber has a larger air flow rate per unit time than the first pipe. When the pneumatic cylinder rapidly increases the pressure applied to the workpiece, the second pipe rapidly exhausts compressed air from the second pressure chamber. Since the second pipe has a structure capable of rapidly exhausting the compressed air from the second pressure chamber, the pressure applied to the work piece by the pneumatic cylinder can be rapidly increased during welding.

According to a fifth aspect of the invention, there is provided a power source for passing a welding current between the first welding electrode and the second welding electrode, and a plurality of objects to be welded are sandwiched between a pair of the welding electrodes from the power source. In a welding apparatus for energizing and welding a welded article, the welding apparatus includes a hydraulic cylinder fixed to a fixed object and a pneumatic cylinder fixed to another fixed object, and the pneumatic piston rod of the pneumatic cylinder is provided with The first welding electrode is fixed, and the second welding electrode is fixed to the hydraulic piston rod of the hydraulic cylinder,
The pneumatic cylinder has a structure in which the length in the forward or backward direction is shorter than that of the hydraulic cylinder, and has a pneumatic piston rod that moves forward at a speed slower than the forward speed of the hydraulic piston rod. The hydraulic cylinder initially advances the hydraulic piston rod until the distance between the welding electrode at a position away from the workpiece and the workpiece is close to a predetermined distance. When the second welding electrode is advanced, the pneumatic cylinder advances the pneumatic piston rod to advance the first welding electrode, and when the welding electrode and the workpiece are in contact with each other, the pneumatic pressure is increased. When a pressure is applied to the work piece through a piston rod, and the pneumatic cylinder applies pressure to the work piece, the power source sends a welding current between a pair of the welding electrodes before And welding the weld object. Therefore, it is not necessary to connect the pneumatic cylinder and the hydraulic cylinder in series with each other, and the lateral deflection of the welding electrode can be reduced.

  According to a sixth aspect of the present invention, a hydraulic piston rod of a hydraulic cylinder fixed to a fixed object moves forward and a pneumatic piston rod of a pneumatic cylinder fixed to the hydraulic piston rod moves between a pair of welding electrodes. A welding method in which energization is started between a pair of welding electrodes in a state where pressure is applied to a plurality of workpieces sandwiched, and the workpiece is welded, and the hydraulic piston rod is advanced. One of the welding electrodes fixed to the pneumatic cylinder and the pneumatic piston rod is advanced, and before the welding electrode and the workpiece to be welded are initially positioned away from the workpiece. The forward movement of the hydraulic piston rod is stopped, and before or after the forward movement of the hydraulic piston rod is stopped, the pneumatic piston rod is delayed compared to the forward speed of the hydraulic piston rod. The welding electrode is advanced at a speed, and one of the welding electrodes is advanced to initially contact the welding electrode and the workpiece to be separated from the workpiece, and the welding electrode and the workpiece are After the contact, the pneumatic cylinder increases the pressure applied to the workpiece, and the pneumatic cylinder increases the pressure applied to the workpiece, while the pneumatic cylinder increases the pressure applied to the workpiece. A welding current is passed between them to weld the workpiece, and then the hydraulic piston rod and the pneumatic piston rod are retracted, and one of the welding electrodes fixed to the pneumatic piston rod is retracted. Therefore, an effect equivalent to that of the first invention can be obtained.

  According to a seventh aspect of the present invention, a pneumatic piston rod of a pneumatic cylinder fixed to a fixed object moves forward, and a hydraulic piston rod of a hydraulic cylinder fixed to the pneumatic piston rod moves forward to move a pair of welding electrodes. A welding method in which energization is started between a pair of welding electrodes in a state in which a pressure is applied to a plurality of workpieces sandwiched between, and the workpiece is welded, and the hydraulic piston rod is advanced. One of the welding electrodes fixed to the hydraulic piston rod is moved forward, and the hydraulic piston rod of the hydraulic piston rod is initially moved before the welding electrode and the workpiece to be welded are in a position apart from the workpiece. Stopping forward, and before or after stopping the forward movement of the hydraulic piston rod, advance the pneumatic piston rod at a speed slower than the forward speed of the hydraulic piston rod, The pressure cylinder and one of the welding electrodes are advanced to bring the welding electrode into contact with the workpiece, and after the welding electrode and the workpiece are in contact, the pneumatic cylinder is applied to the workpiece. During a period in which the pressure is increased and the pneumatic cylinder increases the pressure applied to the workpiece, a welding current is passed between the pair of welding electrodes to weld the workpiece, Since the hydraulic piston rod and the pneumatic piston rod are retracted and one of the welding electrodes is retracted, the same effect as in the second invention can be obtained.

  According to an eighth aspect of the present invention, there is provided a plurality of objects sandwiched between a pair of welding electrodes by the advance of the hydraulic piston rod and the pneumatic piston rod of each of the hydraulic cylinder and the pneumatic cylinder fixed to separate fixed objects. A welding method in which energization is started between a pair of welding electrodes in a state in which a pressure is applied to a workpiece, and the workpiece is welded, and the hydraulic piston rod is advanced and fixed to the hydraulic piston rod. One of the welding electrodes being moved forward, and initially, the advancement of the hydraulic piston rod is stopped before the welding electrode and the workpiece to be welded are in a position apart from the workpiece, Before or after the forward movement of the hydraulic piston rod is stopped, the pneumatic piston rod is advanced at a speed slower than the forward speed of the hydraulic piston rod, so that the pneumatic piston rod The other welding electrode that is fixed is advanced, and initially, the welding electrode and the workpiece to be welded are in a position apart from the workpiece, and the welding electrode and the workpiece are After the contact, the pneumatic cylinder increases the pressure applied to the workpiece, and the pneumatic cylinder increases the pressure applied to the workpiece. A welding current is applied to the workpiece to weld the workpiece, and then the hydraulic piston rod and the pneumatic piston rod are retracted, and both the welding electrodes are retracted. An effect can be obtained.

According to the present invention, the present invention can be applied even when the height of the workpiece is large, that is, when the welding electrode has a large advancing distance and retreating distance, and the time required for each welding in the case of repeated welding (welding tact time). Time) and maintenance can be performed easily.

It is a figure for demonstrating the welding apparatus and welding method which concern on Example 1 of this invention. It is a figure for demonstrating the cylinder part and related part which are used for the welding apparatus which concerns on Example 1 of this invention. It is a figure which shows the timing chart for demonstrating the welding apparatus and welding method which concern on Example 1 of this invention. It is a figure which shows a part of welding apparatus which concerns on Example 2 of this invention.

[Example 1]
A first embodiment of welding according to the present invention will be described with reference to FIGS. FIG. 1 is a diagram illustrating a welding apparatus according to a first embodiment. FIG. 2 is a diagram for explaining an example of the outline and operation of the hydraulic cylinder and the pneumatic cylinder. FIG. 3 is a time chart for explaining the first embodiment of welding according to the present invention. First of all, the term welding is used for general resistance welding such as steel plates, projection welding, and the plastic fluidized part of one work piece sinks into the plastic fluidized hole part of the other work piece at high speed. Ring mash welding to be inserted, or diffusion bonding of dissimilar metals such as a copper material and an aluminum material, which are considered difficult to join. Further, the hydraulic cylinder includes an air hydraulic cylinder that uses air pressure in addition to a general hydraulic cylinder.

  A support mechanism 3 is fixed to a first base member 1 installed on a floor (not shown). The support mechanism 3 may have various structures. For example, the support mechanism 3 includes four support pillars that are set up vertically and fixed to the first base member 1. In FIG. 1, only two support pillars 3A and 3B located on the near side are illustrated. These support columns are parallel to each other. The number of support pillars is preferably four or three, but may be two or more. Alternatively, other structures may be used. An electrode body 5 for holding the first welding electrode 7 is fixed on the first base member 1, and the first welding electrode 7 is fixed thereon.

  A first workpiece W1 and a second workpiece W2 are arranged on the first welding electrode 7. The first work piece W1 and the second work piece W2 are the same kind of metal material or different kind of metal material in which a projection is formed, or a highly conductive metal material such as copper or aluminum. May be. Further, the first work piece W1 has a hole having a predetermined diameter, and a part of the second work piece W2 plastically fluidized during welding is press-fitted into the plastic fluidized hole. There may be. The first workpiece W1 and the second workpiece W2 are not limited to the above. The second welding electrode 9 paired with the first welding electrode 7 will be described later.

  A second base member 11 is attached and fixed to the upper end portion of the support mechanism 3. A columnar member 13 extending upward from the upper surface of the second base member 11 is fixed. The columnar member 13 is preferably four or three cylinders parallel to each other, but may be two or more. In FIG. 1, only two columnar members 13A and 13B on the near side are shown. A support member 15 is attached and fixed to the upper end portion of the columnar member 13. In the first embodiment, the second welding electrode 9 has a long forward and backward distance, so the hydraulic cylinder 17 is required, and the hydraulic cylinder 17 is attached and fixed at the center of the upper surface of the support member 15. . The hydraulic cylinder 17 is a hydraulic cylinder having a general structure, and includes a hydraulic piston rod 17A extending vertically downward from a center portion of a piston (not shown). The maximum forward and backward distance (maximum stroke) of the hydraulic piston rod 17A of the hydraulic cylinder 17 is desirably the maximum from the initial stop position until the second welding electrode 9 contacts the second workpiece W2. It is equal to the length corresponding to 80% or more of the distance. In this case, even if the hydraulic piston rod 17A is advanced at a high speed, the second welding electrode 9 never collides with the second workpiece W2, and the second welding electrode 9 is not connected to the second welding electrode 9. The workpiece can be advanced to a relatively close position of the workpiece W2.

Pipes 19 and 21 through which fluid flows are connected to the hydraulic cylinder 17. The hydraulic piston rod 17 </ b> A extends downward in the support member 15 through a central hole 15 </ b> A provided in the center of the support member 15. The tip of the hydraulic piston rod 17A is attached to the center of the container upper end surface of the pneumatic cylinder 23, and is firmly fixed. Therefore, as the hydraulic piston rod 17A moves forward and backward, the pneumatic cylinder 23 itself moves forward and backward. The pneumatic cylinder 23 according to the first embodiment has a volume and pressure that are not subject to legal regulations. As an example, the pneumatic cylinder 23 has an internal volume of less than 0.04 m ³ (40 liters) and a PV value of 0.02 or less. Thus, the apparatus is greatly reduced in size as compared with the case where it is subject to legal regulations.

  In the first embodiment, the hydraulic cylinder 17 is attached and fixed at the center of the upper surface of the support member 15, but is basically fixed at a predetermined position so that the hydraulic cylinder 17 itself does not move. Just do it. Therefore, the hydraulic cylinder 17 may be fixed to a wall in the vicinity of the welding apparatus (not shown), or may be fixed to another device in the vicinity, or a support pillar provided separately in the vicinity. In this case, since the support member 15 does not need to support the hydraulic cylinder 17, it does not have to be plate-shaped, and a rod-shaped member that works to fix the upper ends of the plurality of columnar members 13 to each other. A combination structure or the like may be used.

  The pneumatic cylinder 23 includes a pneumatic piston rod 23A that is centered on a central axis XY that passes through the central point of the hydraulic piston rod 17A of the hydraulic cylinder 17 and extends in the vertical direction. Here, for distinction, the piston rod of the hydraulic cylinder 17 is referred to as a hydraulic piston rod 17A, and the piston rod of the pneumatic cylinder 23 is referred to as a pneumatic piston rod 23A. The forward movement of the hydraulic piston rod 17A and the pneumatic piston rod 23A is a movement in a direction in which the second welding electrode is brought closer to the first and second workpieces W1 and W2 directions. The backward movement of the pneumatic piston rod 23A is a movement in a direction in which the second electrode is moved away from the workpieces W1 and W2. In other words, in the present invention, the case where the hydraulic piston rod and the pneumatic piston rod extend and become longer is called forward, and the case where the hydraulic piston rod and the pneumatic piston rod become shorter after being immersed is called backward.

  As described above, the maximum stroke of the hydraulic piston rod 17A is 80% or more of the distance (referred to as the maximum distance) from the initial stop position until the second welding electrode 9 comes into contact with the second workpiece W2. In this case, the maximum stroke of the pneumatic piston rod 23A may be 20% or less of the maximum distance from the initial stop position until the second welding electrode 9 comes into contact with the second workpiece W2.

  The side wall portion of the pneumatic cylinder 23 is fixed to a shake prevention member 25, and the shake prevention member 25 moves forward and backward while sliding on the columnar member 13 or via a general rolling bearing (not shown). It acts to prevent the horizontal displacement of the pneumatic cylinder 23, that is, the shake in the direction perpendicular to the central axis XY. Flexible pipes 27 and 29 for allowing gas to flow are connected to the pneumatic cylinder 23. The flexible pipes 27 and 29 have flexibility that can cope with the forward and backward movements of the pneumatic cylinder 23.

  The configuration of the hydraulic cylinder 17 and the pneumatic cylinder 23 will be described in a little more detail with reference to FIG. The hydraulic cylinder 17 has a first pressure chamber 17C and a second pressure chamber 17D that are partitioned by a piston 17B. The pipe 19 communicates with the first pressure chamber 17C, and the pipe 21 communicates with the second pressure chamber 17D. In the middle of the pipes 19 and 21, switching valves 31A and 31B having a general configuration are respectively provided.

  The pneumatic cylinder 23 has a first pressure chamber 23C and a second pressure chamber 23D that are separated by a piston 23B. The flexible pipe 27 communicates with the first pressure chamber 23C. The flexible pipe 29 includes a first flexible pipe 29A, a second flexible pipe 29B, and a third flexible pipe 29C, and communicates with the second pressure chamber 23D. Although the operation will be described in detail later, the flexible pipe 29 is composed of the flexible pipes 29A, 29B, and 29C mainly to enable the pressure in the second pressure chamber 23D to be rapidly reduced. It is. However, if the flexible pipe 29 is a pipe having a large diameter with a large displacement per short time, the pipe 29 may be constituted by a single flexible pipe. In the middle of the four flexible pipes 27, 29A, 29B, 29C, switching valves 31C, 31D, 31E, 31F having a general structure are respectively provided.

  In the first embodiment of the present invention, the pneumatic cylinder 23 has a shorter length in the central axis X-Y direction than the hydraulic cylinder 17, and accordingly, the forward and backward distances of the pneumatic piston rod 23A, That is, the stroke is set shorter than the stroke of the hydraulic piston rod 17A. As an example, when the maximum stroke of the hydraulic piston rod 17A is 100 mm, the maximum stroke of the pneumatic piston rod 23A is 10 mm. In the present invention, the hydraulic cylinder 17 serves to move the pneumatic cylinder 23 and the second welding electrode 9 forward, backward, that is, transport, and the pneumatic cylinder 23 is mainly used for the forging pressure required during welding (the workpiece to be welded during welding To apply pressure).

  Therefore, in order to suppress the above-described PV value to a predetermined value or less, for example, 0.02 or less and limit the volume to less than 40 liters, and to satisfy the forging pressure required at the time of welding, the pneumatic cylinder 23 is The cross-sectional area in the direction perpendicular to the central axis XY is larger than that of the hydraulic cylinder 17, and accordingly, the length in the direction of the central axis XY, that is, the stroke must be shortened. This becomes more noticeable as the forging pressure increases. As described above, if the maximum stroke of the hydraulic piston rod 17A is 80% or more of the maximum distance (the distance from the initial stop position to the second welding electrode 9 contacting the second workpiece W2). Since the maximum forward distance of the pneumatic piston rod 23A may be 20% or less of the maximum distance, it satisfies the above conditions.

  Since the advance distance of the pneumatic piston rod 23A is short, even if the second welding electrode 9 is advanced at a low speed and brought into soft contact with the second workpiece W2, the required time is short. That's it. In the present invention, since the separate hydraulic cylinder 17 and the pneumatic cylinder 23 are connected in series, the second welding electrode 9 is obtained by the pneumatic cylinder 23 having a PV value and a small volume not subject to legal restrictions. Even when the forward distance and the backward distance are large, it is possible to reduce the time required for one-time welding in the case of repeated welding, and to make the second welding electrode 9 softly contact the work piece W2. Can do. In addition, when not subject to laws and regulations, the maintenance is naturally simplified.

  Returning to FIG. 1 and continuing the description, the auxiliary rod 35 is fixed to the tip portion of the pneumatic piston rod 23 </ b> A of the pneumatic cylinder 23 by a fixing member 33. The auxiliary rod 35 is not necessary if the pneumatic piston rod 23A itself has a required length, but the length of the rod is increased when the distance between the second welding electrode 9 and the workpiece W2 is large. It is fixed to adjust the thickness. The center point of the auxiliary rod 35 is located on the center axis XY so that unnecessary force other than the direction of the center axis XY is not applied to the pneumatic piston rod 23A and the hydraulic piston rod 17A. The auxiliary rod 35 extends downward through the hole 11 </ b> A of the second base member 11, and the second welding electrode 9 is attached and fixed to the tip of the auxiliary rod 35. Here, the auxiliary piston 35 and the pneumatic piston rod 23A are used.

  A guide member 37 that guides the auxiliary rod 35 is fixed to the second base member 11. The guide member 37 is in light contact with the outer surface of the auxiliary rod 35 and guides the auxiliary rod 35 so that the auxiliary rod 35 does not shake sideways when the auxiliary rod 35 moves forward and backward. Since the anti-shake member 25 prevents the horizontal displacement of the pneumatic cylinder 23 and the auxiliary rod 35 is guided by the guide member 37 so as not to be laterally shaken, the pressurizing operation of the pneumatic piston rod 23A of the pneumatic cylinder 23 The direction of the pressure applied by the second welding electrode 9 to the first and second workpieces W1 and W2 is perpendicular to the joint surface of the first and second workpieces W1 and W2 with high accuracy. Direction. This contributes to improving the welding quality. Although the above has mainly described the mechanism portion of the welding apparatus, the power source portion will be described next.

  One end of a power supply conductor 41 is connected to the first welding electrode 7, and one end of a flexible power supply conductor 43 is connected to the second welding electrode 9 that performs forward and backward movements. The secondary winding 45B of the welding transformer 45 is connected to the other end of the power supply conductor 41 and the other end of the flexible power supply conductor 43, and the primary winding 45A magnetically coupled thereto is connected to an inverter circuit or a semiconductor switch. A discharge circuit 47 such as a circuit is connected. Connected to the discharge circuit 47 are an energy storage capacitor 49 and a charging circuit 51 for charging the capacitor 49. The charging circuit 51 converts the three-phase AC power from the AC power supply terminals 53A, 53B, and 53C into DC and charges the energy storage capacitor 49. The energy storage capacitor 49 is formed by connecting a number of electrolytic capacitors corresponding to the magnitude of the welding current in parallel. Since the power supply portion may be a known one filed by the present applicant, it will not be described in detail. Note that, depending on the welding conditions, the input power source may be a single-phase AC power source or the like instead of the three-phase AC power source.

  Next, operation | movement of this welding apparatus is demonstrated also using FIG. FIG. 1 is in the initial position, and the distance between the first welding electrode 7 and the second welding electrode 9 is the maximum distance. In this state, the first and second workpieces W1 and W2 are supplied onto the first welding electrode 7 by an automatic supply mechanism (not shown) or an operator. FIG. 3B shows a change in the operating position of the tip of the hydraulic piston rod 17A in the central axis X-Y direction. When an automatic supply mechanism (not shown) starts to move back in the direction of the original position, or when a start switch (not shown) is turned on by an operator, as shown in FIG. 3 (B), the switching valve 31A shown in FIG. 31B starts operation, and fluid (oil) is supplied to the first pressure chamber 17C from the hydraulic tank (not shown) through the switching valve 31A and the pipe 19, and at the same time, the fluid in the second pressure chamber 17D is supplied to the pipe. 21 and the switching valve 31B are returned to an oil tank (not shown).

  Accordingly, as shown by the inclined line b1 in FIG. 3B, the hydraulic piston rod 17A moves forward at a predetermined speed for a predetermined time (in FIGS. 1 and 2, the first and second workpieces are welded). It extends in the direction of W1 and W2.) As the hydraulic piston rod 17A moves forward, naturally the pneumatic cylinder 23 itself moves forward. Therefore, even when the pneumatic piston rod 23A of the pneumatic cylinder 23 does not move, the second welding electrode 9 advances by the maximum stroke of the hydraulic piston rod 17A. At time t1 when the hydraulic piston rod 17A moves forward by the maximum stroke, the switching valve 31A and the switching valve 31B shut off the fluid and hold the pressures in the first pressure chamber 17C and the second pressure chamber 17D as they are. Along with this, as shown by the straight line b2 in FIG. 3B, the hydraulic piston rod 17A stops at the position advanced by the maximum stroke, and holds that position. In this state, the second welding electrode 9 does not contact the second workpiece W2, and the distance between the second welding electrode 9 and the second workpiece W2 is a predetermined distance, for example, about 7 mm. Is definitely away. Thus, even if the hydraulic piston rod 17A moves forward by the maximum stroke, the second welding electrode 9 does not come into contact with the second workpiece W2 and stroke control is unnecessary, so that the hydraulic piston rod 17A moves forward at high speed. Can do.

  Next, similarly, FIG. 3C shows a change in the operating position of the tip of the pneumatic piston rod 23A. Since compressed air is supplied only to the second pressure chamber 23D of the pneumatic cylinder 23 until time t2 immediately after the time t1, the pneumatic piston rod 23A of the pneumatic cylinder 23 does not move forward, and FIG. C) is in a stopped state as indicated by a straight line c1. At this time, the first pressure chamber 23C and the second pressure chamber 23D of the pneumatic cylinder 23 are, for example, peak values of the applied pressure (forging pressure) applied to the first and second workpieces W1 and W2 during welding. It is desirable that the value be held in the vicinity. At time t2, compressed air is supplied from a compressed air supply source (not shown) to the first pressure chamber 23C of the pneumatic cylinder 23 through the switching valve 31C and the flexible pipe 27.

  At this time, as an example, the second pressure chamber 23D of the pneumatic cylinder 23 is connected to a compressed air supply source (not shown) through at least one of the switching valves 31D to 31F. The pressure in the second pressure chamber 23D is maintained at a constant value. Accordingly, the piston 23B and the pneumatic piston rod 23A of the pneumatic cylinder 23 have a pressure P1 in the first pressure chamber 23C and a pressure P2 in the second pressure chamber 23D, as indicated by a straight line c2 in FIG. It moves forward by the difference (P1-P2).

  Therefore, the pneumatic piston rod 23A can be advanced at a desired speed by adjusting the rate of increase of the pressure difference (P1-P2), so that the second welding electrode 9 is moved to the second workpiece W2. It is possible to touch the software without giving an unnecessary impact. Since the advance distance (stroke) of the pneumatic piston rod 23A of the pneumatic cylinder 23 is shorter than the hydraulic piston rod 17A of the hydraulic cylinder 17, even if the pneumatic piston rod 23A is advanced at a low speed, the required time is reduced. It can be suppressed in a short time. When the pneumatic piston rod 23A moves forward, since the guide member 37 prevents the auxiliary rod 35 coupled to the pneumatic piston rod 23A from sideways, the second welding electrode 9 is used as the second work piece W2. It is possible to apply vertical pressure with high accuracy. This also contributes to improving the welding quality.

  In the example described above, the pneumatic piston rod 23A of the pneumatic cylinder 23 moves forward by about 7 mm when the maximum stroke in the first embodiment is 10 mm, and as shown in FIG. The welding electrode 9 comes into contact with the second workpiece W2 and stops, and holds the stop position until time t4. Accordingly, as shown by a straight line c3 in FIG. 3C, the first and second workpieces W1 and W2 are shown by a straight line a1 in FIG. 3A during the period from time t3 to t4. The pressure difference (P1-P2) and the applied pressure corresponding to the weight of the second welding electrode 9, the pneumatic piston rod 23A, the piston 23B, the fixing member 33, and the auxiliary rod 35 are Applied. The applied pressure during this period (time t3 to t4) is the contact state between the first welding electrode 7 and the first workpiece W1, the first workpiece W1 and the second workpiece W2. The contact state between the second workpiece W2 and the second welding electrode 9 is stabilized, thereby contributing to the improvement of the welding quality.

  Next, as shown in FIG. 3D, when the forging pressure application signal S is issued at time t4, the switching valves 31D to 31F are switched to the exhaust side, and the pressure in the second pressure chamber 23D of the pneumatic cylinder 23 is changed. Is rapidly depressurized. At this time, the first pressure chamber 23C of the pneumatic cylinder 23 is connected to a compressed air supply source (not shown) through the switching valve 31C and the flexible pipe 27. Therefore, the piston 23B of the pneumatic cylinder 23 receives a force in a rapidly increasing forward direction (downward in FIGS. 1 and 2), so that the workpieces W1 and W2 have a straight line a2 in FIG. 3A. Subjected to suddenly increasing forging pressure as shown.

  On the other hand, the energy storage capacitor 49 is charged to a desired voltage by the charging circuit 51 by time t4 at the latest, and stores predetermined electrical energy. Immediately after time t4 or at time t5 after the set time, the charging circuit 51 performs a predetermined switching operation, whereby the primary winding 45A, the secondary winding 45B, and the first welding electrode 7 of the welding transformer 45 are performed. And the welding current Iw as shown in FIG.3 (E) flows into the 1st, 2nd to-be-welded object W1, W2 through the 2nd welding electrode 9. FIG. In the case of the above-described ring mash welding, or when the first and second workpieces W1 and W2 are aluminum materials or copper materials having higher electrical conductivity and melting temperature than aluminum materials, or first and second When one of the workpieces W1 and W2 is made of an aluminum material and the other is made of a copper material, the welding current Iw is a pulsed welding current, for example, a peak having a pulse width of about 20 ms or less, preferably about 10 ms or less. A current having a large value, for example, a current having a peak value of several thousand amperes to several million amperes. Although not particularly illustrated, the welding apparatus according to the first embodiment preferably allows such a steep pulse current having a narrow pulse width to flow between the first and second workpieces W1 and W2. In addition, the current paths through which the discharge current of the energy storage capacitor 49 such as the power supply conductors 41 and 43, the welding transformer 14 and the discharge circuit 47 has a structure that minimizes the inductance.

  In the process in which the forging pressure applied to the first and second workpieces W1 and W2 is rapidly increasing, the welding current Iw flows through the first and second workpieces W1 and W2, and the welding points are plastic. When starting to fluidize, because of the large forging pressure that is increasing rapidly, the welded part that is plastically fluidizing sinks, so ring mash welding, welding of dissimilar metals, or welding of metals with very high conductivity Even if it exists, the welding result with high welding quality can be obtained.

  Explaining this point in detail, for example, when the welding current Iw is a single pulsed current having a large peak value with a narrow pulse width of about 20 ms or less, the heat generation at the welded portion rapidly increases in a short time, Since heat escaping to the four surroundings of the welded portions of the first and second workpieces W1 and W2 can be suppressed, the welded portion can be plastically fluidized in a short time without discoloring and deforming the surroundings. In addition to this, by increasing the exhaust speed of the second pressure chamber 23D of the pneumatic cylinder 23, the increasing speed of the forging pressure is increased, and the welded portion is plasticized in the process where the forging pressure is rapidly increasing. Since the plastic fluidized portion is submerged in response to the plastic fluidization at a high speed, the welded portion is welded in a preferable state. In other words, even in ring mash welding, welding of dissimilar metals, or welding of metals with very high conductivity, the welding area is not discolored or deformed, improving the welding quality, such as increasing the welding strength. Can be made. Strictly speaking, the pneumatic piston rod 23A slightly advances at this time, but is smaller than the distance to advance until the second welding electrode 9 is brought into contact with the second workpiece W2, so that FIG. Ignored in (C).

  In order to stabilize the welding and ensure the welding quality, the forging pressure is held almost constant until time t6 as shown by the straight line a3 in FIG. The 17 hydraulic piston rods 17A and the pneumatic piston rod 23A of the pneumatic cylinder 23 begin to move backward. At this time, the pneumatic cylinder 23 preferably retracts the pneumatic piston rod 23A by increasing the internal pressure of the second pressure chamber 23D while returning the internal pressure of the first pressure chamber 23C to atmospheric pressure. The hydraulic piston rod 17A of the hydraulic cylinder 17 moves backward by a predetermined maximum stroke to prepare for the next welding.

  The welding apparatus and welding method according to the first embodiment can be applied to resistance welding such as projection welding of a general metal material such as a steel plate as described above. In this case, if necessary, the welding current Iw may be applied during the period in which the forging pressure is held substantially constant (straight line a3), as indicated by the straight line a3 in FIG. When the first and second workpieces W1 and W2 are made of high carbon steel that has been carburized and quenched to the inside, the pressure applied to the first and second workpieces W1 and W2 is almost equal. It is also possible to manage the length of the period that is kept constant and to pass a current for tempering during that period.

  When this processing is performed, the applied pressure is maintained as it is, or the hydraulic cylinder 17 is maintained as it is, the pneumatic piston rod 23A of the pneumatic cylinder 23 is moved backward, and the first and second welds are temporarily performed. The applied pressure applied to the objects W1 and W2 may be removed. Then, again, as described above, the switching valve or the like is controlled to advance the pneumatic piston rod 23A, and a predetermined pressure is applied to the first and second workpieces W1 and W2 for tempering. An electric current may be passed. In this case, it is possible to shorten the time required to apply the pressurization after once removing the pressurization applied to the first and second workpieces W1 and W2. If necessary, the pulsed welding current Iw and the pulsed current for tempering may be two or more.

  In Example 1, immediately after the advance of the hydraulic piston rod 17A of the hydraulic cylinder 17 stops, the pneumatic piston rod 23A of the pneumatic cylinder 23 starts to advance, but simultaneously with the stop of the advance of the hydraulic piston rod 17A, Alternatively, the pneumatic piston rod 23A may start moving immediately before stopping. Further, the timing of the backward movement of the hydraulic piston rod 17A and the backward movement of the pneumatic piston rod 23A may not be the same. The advance timing of the pneumatic piston rod 23A may be within a range in which the second welding electrode 9 does not contact the second workpiece W2 when the hydraulic piston rod 17A stops moving forward. Further, by controlling the exhaust timing time of the switching valves 31D to 31F shown in FIG. 2 according to the type of welding or the material of the workpiece, the pressure applied by the straight line a2 in FIG. It is possible to adjust the slope.

[Example 2]
Embodiment 2 of the present invention will be described with reference to FIG. In the second embodiment, the pneumatic cylinder is fixed at a predetermined position, the hydraulic cylinder is fixed to the pneumatic piston rod, and the second welding electrode is fixed to the hydraulic piston rod. Therefore, FIG. 4 does not show the whole welding apparatus, but shows only a main part in which the welding apparatus of FIG. 1 is changed. In FIG. 4, the same symbols as those shown in FIG. 1 indicate members having the same names.

  A pneumatic cylinder 23 is fixed at the center of the upper surface of the support member 15. Although not shown, the pneumatic cylinder 23 is firmly fixed to the support member 15 by a bolt or the like, for example. The outline of the pneumatic cylinder 23 has a structure as shown in FIG. 2, but the pipe 27 connected to the first pressure chamber 23C and the pipe 29 connected to the second pressure chamber 23D are flexible. There is no need to be. Also in the second embodiment, the pipe 29 is composed of a plurality of pipes or pipes having a large diameter in order to increase the exhaust capacity. The pneumatic piston rod 23A of the pneumatic cylinder 23 extends in the forward direction through the central hole 15A of the support member 15.

  The hydraulic cylinder 17 itself is fixed to the tip of the pneumatic piston rod 23A. The hydraulic cylinder 17 is fixed to the pneumatic piston rod 23A so that the central point of the hydraulic piston rod 17A exists on the central axis XY extending in the forward direction through the central point of the pneumatic piston rod 23A. To do. The hydraulic piston rod 17 </ b> A extends in the forward direction through the central hole 11 </ b> A of the second base member 11. The 2nd welding electrode 9 is attached to the front-end | tip part of the hydraulic piston rod 17A by arbitrary fixing methods. The second welding electrode 9 is attached so that the center point thereof is substantially located on the central axis XY.

  A flexible pipe 19 through which fluid flows is connected to the first pressure chamber 17C shown in FIG. 2 in the hydraulic cylinder 17, and a flexible pipe through which fluid flows is connected to the second pressure chamber 17D. A pipe 21 is connected. Even if the pipes 19 and 21 are not flexible, they do not adversely affect the forward and backward movements of the hydraulic cylinder 17. The hydraulic piston rod 17 </ b> A is guided by the guide member 37 so as not to move sideways, and moves forward and backward. Also in the second embodiment, the hydraulic cylinder 17 has a longer forward and backward stroke than the pneumatic cylinder 23, but the diameter is small and the change in pressure is small. Accordingly, the hydraulic piston rod 17 </ b> A can be moved forward and backward by only the action of the guide member 37 without laterally moving. In FIG. 1, the pneumatic cylinder 23 is moved forward and backward while being supported by the shake preventing member 25. However, in the second embodiment, the hydraulic cylinder 17 is not supported by the shake preventing member. Therefore, the structure can be simplified, reduced in size, and reduced in cost. However, if necessary, the hydraulic cylinder 17 may be supported by a shake preventing member as in FIG.

  Since the operation is almost the same as that of the first embodiment, it will be briefly described. First, the hydraulic piston rod 17A of the hydraulic cylinder 17 advances at a high speed by a predetermined maximum stroke and stops. As a result, the second welding electrode 9 advances to a position away from the second workpiece W2 by a slight predetermined distance and stops. Next, the pneumatic piston rod 23A of the pneumatic cylinder 23 advances at a low speed, and the hydraulic cylinder 17 and the second welding electrode 9 are advanced at a low speed to softly contact the second workpiece W2. First, a considerably small pressure is applied between the workpieces as compared with the forging pressure. Next, the pneumatic cylinder 23 applies a pressing force that rapidly increases via the hydraulic cylinder 17 to the workpieces, and in this state, a welding current is applied to weld the workpieces together. After welding, the hydraulic cylinder 17 and the pneumatic cylinder 23 retract the hydraulic piston rod 17A and the pneumatic piston rod 23A, respectively, to separate the second welding electrode 9 from the second workpiece W2.

  Also in the second embodiment, the hydraulic piston rod 17A moves forward by the maximum stroke without adjustment to advance the second welding electrode 9 to a predetermined position close to the second workpiece W2, and the pneumatic piston rod 23A is Since the second workpiece W2 is contacted only by advancing a short distance, the hydraulic piston rod 17A can be advanced at high speed until the second welding electrode 9 contacts the second workpiece W2. In addition, the second welding electrode 9 can be softly brought into contact with the second workpiece W2 by advancing the pneumatic piston rod 23A at a low speed. In addition, it is difficult to obtain good welding quality with the conventional welding method by applying a pulsed welding current during a period in which a rapidly increasing pressure is applied to the workpiece by the pneumatic cylinder 23. Also in the above-described ring mash welding, welding of different metal materials, or welding of a highly conductive metal material, the welding quality such as welding appearance and strength can be improved.

  In addition, although the capacitor-type welding apparatus has been described as a preferable example in the above-described first and second embodiments, the pulse width of the welding current is used when the first and second workpieces W1 and W2 are steel plates or the like. However, it is not necessary that the current has a narrow steep waveform as described above. Therefore, instead of a capacitor-type welding apparatus, a welding power source that can control the welding current waveform to an appropriate waveform by an inverter circuit may be used. In the first and second embodiments, the second welding electrode 9 positioned above is moved forward and backward. However, the first welding electrode 7 positioned below may be moved forward and backward.

  An example of this case will be briefly described in correspondence with the first embodiment shown in FIG. 1. A hydraulic cylinder 17 is fixed on the first base member 1, and the hydraulic piston rod 17A is directed vertically upward. The pneumatic cylinder 23 is fixed to the first, and the first welding electrode 7 is fixed to the pneumatic piston rod 23A facing vertically upward. The first welding electrode 7 can be moved together by the forward or backward movement of the hydraulic piston rod 17A or the pneumatic piston rod 23A. In this case, the second welding electrode 9 is generally fixed at a predetermined position, but both the first welding electrode 7 and the second welding electrode 9 are advanced in the opposite directions as described below. A configuration for retreating (not shown) may be used.

  This will be described with reference to the first and second embodiments shown in FIG. 1 or FIG. 4. The hydraulic cylinder 17 or the pneumatic cylinder 23 is fixed to the support member 15, and the hydraulic piston rod 17A extends vertically downward. Alternatively, the second welding electrode 9 is fixed to the pneumatic piston rod 23A. Then, the pneumatic cylinder 23 or the hydraulic cylinder 17 is fixed on the first base member 1, and the first welding electrode 7 is fixed to the pneumatic piston rod 23A or the hydraulic piston rod 17A directed vertically upward. May be. In this case, the first welding electrode 7 and the second welding electrode 9 are moved forward and backward in opposite directions, and the second welding electrode 9 or the first welding electrode fixed to the hydraulic piston rod 17A. 7 advances and retracts a long distance, and the first welding electrode 7 or the second welding electrode 9 fixed to the pneumatic piston rod 23A advances and retracts a short distance.

  Also in this case, the hydraulic piston rod 17A lowers the second welding electrode 9 or raises the first welding electrode 7 until the second welding electrode 9 and the workpiece W2 are at a predetermined interval, and thereafter The pneumatic piston rod 23A raises the first welding electrode 7 or lowers the second welding electrode 9 to softly contact the second welding electrode 9 and the workpiece W2. In this case, since both welding electrodes are moved, there is a problem that the configuration is complicated in this respect, but the hydraulic cylinder 17 and the pneumatic cylinder 23 are not directly connected in series. Since it is fixed, there is no side-shake, and therefore there is an effect that the side-shake prevention measure can be omitted.

  In addition, depending on the workpiece, either or both of the welding electrodes may be configured to be able to advance and retract in the horizontal direction, and the workpiece to be placed on a welding table (not shown) may be pressurized from both the left and right sides. Of course, it may be welded. In this case as well, as in the first embodiment, the pneumatic cylinder 23 is fixed to the hydraulic piston rod 17A extending in the horizontal direction of the fixed hydraulic cylinder 17, and the second is fixed to the pneumatic piston rod 23A in the horizontal direction. The welding electrode 9 is fixed. Alternatively, as in the second embodiment, the hydraulic cylinder 17 is fixed to the pneumatic piston rod 23A extending in the horizontal direction of the fixed pneumatic cylinder 23, and the second welding electrode is connected to the hydraulic piston rod 17A in the horizontal direction. 9 may be fixed. Moreover, the structure which the 1st welding electrode 7 advances and retreats similarly may be sufficient. Also in this case, since the maximum stroke of the hydraulic piston rod 17A is long, it is preferable to guide the hydraulic piston rod 17A in the horizontal direction with the anti-shake member in order to prevent the horizontal and vertical shakes.

  Furthermore, the first welding electrode 7 may be fixed to the hydraulic piston rod 17A or the pneumatic piston rod 23A, and the second welding electrode 9 may be fixed to the pneumatic piston rod 23A or the hydraulic piston rod 17A. In this case, although the first welding electrode 7 and the second welding electrode 9 move at different distances, both move forward and backward. In these cases as well, as described above, the maximum stroke of the hydraulic piston rod 17A is the distance (referred to as the maximum distance) from the initial stop position until the second welding electrode 9 contacts the second workpiece W2. .) Is 80% or more, and the maximum stroke of the pneumatic piston rod 23A is 20% or less of the maximum distance from the initial stop position until the second welding electrode 9 contacts the second workpiece W2. It is desirable.

  Further, in addition to the above-mentioned claims, as an example of the present invention, the pneumatic cylinder or the pneumatic piston rod is guided to prevent lateral deflection, so that the welding surfaces of the workpieces are mutually connected. Since the vertical pressure can be applied, the welding quality can be further improved.

  In addition, as an example of the present invention, the anti-vibration member for preventing lateral displacement of the hydraulic piston rod when the hydraulic piston rod moves forward or backward is provided along the hydraulic piston rod. Since it is possible to apply pressure forces in the vertical direction to each other, the welding quality can be further improved.

In addition, as an example of the present invention, since the internal volume of the pressure vessel of the pneumatic cylinder is as small as less than 0.04 m ³ , no special inspection or the like is necessary, and maintenance is easy.

  Further, as an example of the present invention, since a welding current is passed between a pair of welding electrodes during a period in which the pressure applied to the workpiece is rapidly increased by the pneumatic cylinder, the plastic flow of the welding portion of the workpiece is welded. Therefore, welding of dissimilar metal materials, which has been conventionally difficult to obtain high weld quality, as well as general welding of the same kind of metal, etc. Ring mash welding or the like is also possible, and the welding quality can be improved.

  Further, as an example of the present invention, the pneumatic cylinder has a first pressure chamber and a second pressure chamber separated by a piston, as compared to a first pipe connected to the first pressure chamber. The second pipe connected to the second pressure chamber has a larger air flow rate per unit time than the first pipe, and the welding electrode and the work piece are in contact with each other. Supplying the air to the first pressure chamber without exhausting the second pressure chamber, and moving the pneumatic piston rod forward at a speed slower than the forward speed of the hydraulic piston rod; The welding electrode and the work piece are brought into contact at a low speed, and after the welding electrode and the work piece are in contact, the pneumatic cylinder is exhausted at a high speed to advance the pneumatic piston rod. By rapidly increasing the direction force, Such pressure on the abutment is rapidly increased. Therefore, although the welding electrode and the workpiece can be softly contacted without giving an impact to the workpiece, a rapidly increasing pressure can be applied to the workpiece during welding. The responsiveness of the operation of the welding electrode can be improved.

  Further, as an example of the present invention, after welding, the pressure is applied to the workpiece, or the pneumatic piston rod is retracted once and then advanced again to apply a predetermined pressure again to the workpiece. Since the tempering process is performed by supplying a current again with the predetermined pressure applied to the workpiece, the tempering process is performed in a short time. Can be returned.

  Resistance welding between workpieces made of general metal materials such as steel plates, or between workpieces made of highly conductive metal materials such as copper or aluminum materials, or between workpieces made of these different metal materials It can be applied to various types of welding such as diffusion bonding and ring mash welding.

W1 ... first workpiece W2 ... second workpiece 1 ... first base member 3 ... support mechanism 3A, 3B ... support pillar 5 ... electrode body 7 ... 1st welding electrode 9 ... 2nd welding electrode 11 ... 2nd base member 13 ... Columnar member 13A, 13B ... Columnar member 15 ... Supporting member 15A ... Central hole 17 of support member 17 ... Hydraulic cylinder 17A ... Hydraulic piston rod 17B ... Piston 17C ... First pressure chamber 17D ... Second pressure chamber 19, 21 ... Pipe 23 ... Pneumatic cylinder 23A ... Pneumatic piston rod 23B ... Piston 23C ... First pressure chamber 23D ... Second pressure chamber 25 ... Shake prevention member 27 ... Pipe 29, 29A-29C ... Pipes 31A-31F Valve 33 ... Fixing member 35 ... Auxiliary rod 37 ... Guide member 41 ... Power supply conductor 43 ... Flexible power supply conductor 45 ... Welding transformer 45A ... Primary winding 45B ...・ Secondary winding 47 ... Discharge circuit 49 ... Energy storage capacitor 51 ... Charging circuit 53A to 53C ... AC power supply terminal

Claims (8)

A power source for passing a welding current between the first welding electrode and the second welding electrode; and energizing the workpiece from the power source with a plurality of workpieces sandwiched between the pair of welding electrodes. In welding equipment for welding,
A hydraulic cylinder fixed to a fixed object;
A pneumatic cylinder fixed to the hydraulic piston rod of the hydraulic cylinder and moving forward or backward together as the hydraulic piston rod moves forward or backward;
With
The pneumatic cylinder has a structure in which the length in the forward or backward direction is shorter than that of the hydraulic cylinder, and has a pneumatic piston rod that moves forward at a speed slower than the forward speed of the hydraulic piston rod. And
The second welding electrode or the first welding electrode is fixed to a pneumatic piston rod of the pneumatic cylinder,
The hydraulic cylinder initially advances the hydraulic piston rod until the distance between the welding electrode at a position away from the workpiece and the workpiece approaches a predetermined distance, and the pneumatic cylinder Advancing the second welding electrode or the first welding electrode fixed to a cylinder and the pneumatic piston rod;
The pneumatic cylinder applies pressure to the workpiece through the pneumatic piston rod when the welding electrode and the workpiece are in contact with each other.
When the pneumatic cylinder is applying pressure to the workpiece, the power source welds the workpiece by passing a welding current between a pair of welding electrodes. A power source for passing a welding current between the first welding electrode and the second welding electrode; and energizing the workpiece from the power source with a plurality of workpieces sandwiched between the pair of welding electrodes. In welding equipment for welding,
A pneumatic cylinder fixed to a fixed object;
A hydraulic cylinder fixed to the pneumatic piston rod of the pneumatic cylinder and advanced or retracted together with advancement or retraction of the pneumatic piston rod;
With
The pneumatic cylinder has a structure in which the length in the forward or backward direction is shorter than that of the hydraulic cylinder, and the pneumatic cylinder moves forward at a speed slower than the forward speed of the hydraulic piston rod of the hydraulic cylinder. Having a piston rod,
The second welding electrode or the first welding electrode is fixed to the hydraulic piston rod;
The hydraulic cylinder initially advances the hydraulic piston rod until the distance between the welding electrode and the workpiece to be welded at a position apart from the workpiece to be welded approaches a predetermined distance,
The pneumatic cylinder advances the pneumatic piston rod to advance the second welding electrode or the first welding electrode fixed to the hydraulic cylinder and the hydraulic piston rod, and the welding electrode and the When contacted with the workpiece, a pressure is applied to the workpiece through the pneumatic piston rod and the hydraulic cylinder,
When the pneumatic cylinder is applying pressure to the workpiece, the power source welds the workpiece by passing a welding current between a pair of welding electrodes. In claim 1 or claim 2,
The maximum stroke of the hydraulic piston rod is 80% or more of the maximum distance between the welding electrode and the workpiece to be welded at an initial position away from the workpiece, and the pneumatic piston rod A welding apparatus having a maximum stroke of 20% or less of the maximum distance. In any one of Claims 1 thru | or 3,
The pneumatic cylinder has a first pressure chamber and a second pressure chamber separated by a piston;
Compared with the first pipe connected to the first pressure chamber, the second pipe connected to the second pressure chamber has a larger air flow rate per unit time than the first pipe. When the pneumatic cylinder rapidly increases the pressure applied to the workpiece, the second pipe rapidly exhausts compressed air from the second pressure chamber. apparatus. A power source for passing a welding current between the first welding electrode and the second welding electrode; and energizing the workpiece from the power source with a plurality of workpieces sandwiched between the pair of welding electrodes. In welding equipment for welding,
A hydraulic cylinder fixed to a fixed object;
A pneumatic cylinder fixed to another fixed object;
With
The first welding electrode is fixed to a pneumatic piston rod of the pneumatic cylinder,
The second welding electrode is fixed to a hydraulic piston rod of the hydraulic cylinder,
The pneumatic cylinder has a structure in which the length in the forward or backward direction is shorter than that of the hydraulic cylinder, and has a pneumatic piston rod that moves forward at a speed slower than the forward speed of the hydraulic piston rod. And
The hydraulic cylinder initially advances the hydraulic piston rod until the distance between the welding electrode located at a position distant from the work piece and the work piece approaches a predetermined distance. The welding electrode of
The pneumatic cylinder advances the pneumatic piston rod to advance the first welding electrode. When the welding electrode and the workpiece are in contact with each other, a pressure is applied through the pneumatic piston rod to the welding target. Give to things,
When the pneumatic cylinder is applying pressure to the workpiece, the power source welds the workpiece by passing a welding current between a pair of welding electrodes. Due to the advance of the hydraulic piston rod of the hydraulic cylinder fixed to the fixed object and the advance of the pneumatic piston rod of the pneumatic cylinder fixed to the hydraulic piston rod, a plurality of objects sandwiched between a pair of welding electrodes A welding method in which energization is started between a pair of the welding electrodes in a state in which a pressure is applied to a welded object, and the workpiece is welded,
The hydraulic piston rod is advanced to advance the pneumatic cylinder and one of the welding electrodes fixed to the pneumatic piston rod. Initially, the welding electrode and the object to be welded are positioned away from the workpiece. Stop the advance of the hydraulic piston rod before it comes into contact with the weldment,
Before or after stopping the forward movement of the hydraulic piston rod, the pneumatic piston rod is advanced at a speed slower than the forward speed of the hydraulic piston rod, and one of the welding electrodes is advanced to the initial stage. Contacting the welding electrode and the workpiece to be welded at a position away from the workpiece;
After the welding electrode and the workpiece are in contact, the pneumatic cylinder increases the pressure applied to the workpiece,
During the period in which the pneumatic cylinder increases the pressure applied to the workpiece, a welding current is passed between the pair of welding electrodes to weld the workpiece.
Then, the hydraulic piston rod and the pneumatic piston rod are retracted, and the one welding electrode fixed to the pneumatic piston rod is retracted. The pneumatic piston rod of the pneumatic cylinder fixed to the fixed object advances and the hydraulic piston rod of the hydraulic cylinder fixed to the pneumatic piston rod advances, so that a plurality of sandwiched between a pair of welding electrodes A welding method for welding the workpiece by starting energization between a pair of the welding electrodes in a state where a pressure is applied to the workpiece,
The hydraulic piston rod is advanced to advance one of the welding electrodes fixed to the hydraulic piston rod, and initially, the welding electrode at a position away from the workpiece is in contact with the workpiece. Before stopping the advance of the hydraulic piston rod,
Before or after stopping the forward movement of the hydraulic piston rod, the pneumatic piston rod is advanced at a speed slower than the forward speed of the hydraulic piston rod to advance the hydraulic cylinder and one of the welding electrodes. The welding electrode and the workpiece to be welded,
After the welding electrode and the workpiece are in contact, the pneumatic cylinder increases the pressure applied to the workpiece,
During the period in which the pneumatic cylinder increases the pressure applied to the workpiece, a welding current is passed between the pair of welding electrodes to weld the workpiece.
Thereafter, the hydraulic piston rod and the pneumatic piston rod are retracted, and one of the welding electrodes is retracted. By applying the hydraulic piston rod and the pneumatic piston rod of each of the hydraulic cylinder and pneumatic cylinder fixed to separate fixed objects, pressure is applied to the workpieces sandwiched between a pair of welding electrodes. A welding method in which energization is started between a pair of the welding electrodes in a state of being applied, and the workpiece is welded,
The hydraulic piston rod is advanced to advance one of the welding electrodes fixed to the hydraulic piston rod, and initially, the welding electrode at a position away from the workpiece is in contact with the workpiece. Stop the advance of the hydraulic piston rod before
Before or after stopping the forward movement of the hydraulic piston rod, the pneumatic piston rod is advanced at a speed slower than the forward speed of the hydraulic piston rod, and the other of the hydraulic piston rod is fixed to the pneumatic piston rod. Advancing the welding electrode, and initially contacting the welding electrode with the welding electrode at a position away from the workpiece,
After the welding electrode and the workpiece are in contact, the pneumatic cylinder increases the pressure applied to the workpiece,
During the period in which the pneumatic cylinder increases the pressure applied to the workpiece, a welding current is passed between the pair of welding electrodes to weld the workpiece.
Thereafter, the hydraulic piston rod and the pneumatic piston rod are retracted, and both the welding electrodes are retracted.

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