JPH10137945A - Spot welding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve feeding reliability and to reduce feeding loss to an electrode, in using a type of welding machine for which an electrode is attached to the tip end of a horizontally movable arm on a work table, by providing a raising/lowering member at the tip end of the arm, connecting an axial electrode to a pressure cylinder installed on that member, and thereby enabling a large movement upward from the table surface. SOLUTION: With a supporting plate 3 provided at the tip end of an arm 1 that is movable in the horizontal direction of a welding machine, a raising/ lowering member 51 is supported so as to make it vertically movable by hydraulic pressure and also fixable. In addition, an L-shaped bracket 63 is attached to the front lower part of the raising/lowering member 51, with an axial electrode 65 made vertically movable in the center of the bracket by means of an electrode guide 67. Further, an electrode tip 71 is fitted attachably/detachably to the lower end of the electrode 65, with a handle 75 installed, at an adequate height of the electrode 65. for adjusting the height/position of the electrode 65. On the other hand, one end of the secondary power supply cable 77 connected to the power source is connected to the upper end of the electrode 65 through a swivel joint 79.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spot welding machine, and more particularly, to an arm provided at a position above a work table serving as a lower electrode so as to be movable in a horizontal direction. The present invention relates to a spot welding machine of a type provided with a rod-shaped (shaft-shaped) electrode capable of vertically moving.

[0002]

2. Description of the Related Art As a prior art relating to the present invention, for example, Japanese Patent Application Laid-Open No. Sho 55-112182 (Prior Art 1),
No. 0423 (Prior example 2).

[0003]

In the above-mentioned prior art example 1, the welding head, which is vertically movable at the tip of an arm which is horizontally movable above the table, cannot be raised significantly. For example, when spot welding is performed on the bottom inside a deep box, there is a problem that the head cannot be largely moved upward from the table upper surface, and the welding head cannot be moved inside the box.

In the prior art example 2, a rod-like electrode is provided at the tip of an arm provided horizontally movably above the table so as to be largely movable vertically.
The electrode can be raised significantly from the table upper surface, and there is no problem as in the first prior art.

However, in the prior art example 2, a pair of horizontal arms is pivotally mounted on a horizontal arm base provided at the end of the arm so as to be vertically movable, and the horizontal arm is used to connect a copper cylindrical pipe (rod-shaped) electrode. In a state where the horizontal arm base is lowered by a cylinder in a state of being clamped and fixed, the electrode is pressurized. And since the electrode moves up and down greatly, if the power supply table is directly connected to the electrode,
Since the bending of the cable greatly changes and a power cable that is thick and hard to be bent cannot be directly connected to the electrode, power is supplied to the rod-shaped electrode through the holding portion of the horizontal arm. That is, a cable for supplying a low voltage and a large current has a large cross-sectional area, so that it is difficult to bend. In addition, since it is generally made of copper, aluminum, or the like, it is weak to repeated bending, and is largely up and down. No direct connection to the moving electrode is contemplated.

Therefore, also in the prior art example 2, when the electrode is raised significantly, the clamping by the horizontal arm is released, and when pressure is applied for spot welding, the electrode is clamped again by the horizontal arm. Things.

Therefore, the position where the horizontal arm sandwiches and fixes the electrode is not constant, and the contact resistance between the horizontal arm and the electrode greatly changes, which causes a problem in stable power supply. Also,
There is a problem that the electrode is lengthened due to large vertical movement, and the loss due to resistance is increased. Further, since the material of the electrode needs to be made of copper, the holding portion fixed by the horizontal arm is easily deformed, and there is a problem in the life of the rod-shaped electrode.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and the invention according to claim 1 is to vertically move an elevating member on a tip end of an arm movable in a horizontal direction. A shaft-shaped electrode provided with an electrode tip at the lower end is connected to a pressurizing cylinder attached to the movable member so as to be movable and fixed.

According to a second aspect of the present invention, in the first aspect of the present invention, the shaft-shaped electrode is provided so as to penetrate the pressure cylinder, and a secondary end is connected to an upper end portion of the shaft-shaped electrode via a swivel joint. The power cable is connected.

According to a third aspect of the present invention, in the first aspect of the present invention, the shaft electrode is supported by an electrode holder provided on the pressing cylinder so as to be able to rotate only horizontally, and the upper end of the shaft electrode is provided. A secondary power cable is connected to the unit via a swivel joint.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the shaft electrode is provided with an annular handle.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A spot welding machine according to this embodiment is provided with a table (not shown) for placing a work (not shown), as in the preceding first and second examples, and one side of the table. An arm is provided at the upper end portion of a column erected in the form of a link so as to be movable in the horizontal direction. Note that the overall configuration of the spot welding machine may be the same as in the above-described first and second examples, and therefore a detailed description of the overall configuration will be omitted.

Referring to FIG. 1, in a spot welding machine according to a first example, a support plate 3 is attached to a distal end portion of an arm 1 movably provided in a horizontal direction above a table (not shown). The support plate 3 is provided with a clamp unit 7 as an example of a fixing device capable of fixing a vertically movable rod-shaped elevating member 5 immovably.

The clamp unit 7 has a clamp cylinder 9 attached to the support plate 3 and a collet chuck 11 vertically penetrated at the center of the clamp cylinder 9 and integrally fixed thereto. The elevating member 5 penetrates the collet chuck 11 so as to be vertically movable.

In order to open and close the collet chuck 11, the cylinder 9 is provided with a sleeve 13 surrounding the collet chuck 11 so as to be movable up and down. The piston 15 is integrally mounted.

Accordingly, in the clamp unit 7, when the working fluid is supplied to the cylinder 9 to raise the piston 15, the sleeve 13 integrally rises and closes the collet chuck 11, so that the elevating member 5 cannot be moved up and down. Can be fixed to Further, when the piston 15 and the sleeve 13 are lowered, the collet chuck 11 is opened and the fixing of the elevating member 5 is released, so that the elevating member 5 can be moved up and down.

A bracket 17 is attached to the elevating member 5. In this example, the bracket 17 is provided integrally with the elevating member 5, and the bracket 1
7 also constitutes a part of the elevating member. The bracket 17 has a U-shape having bent portions 17U and 17L at upper and lower portions, and upper and lower bent portions 17U and 17L are fixed to upper and lower ends of the elevating member 5. Therefore, in this example, even when the collet chuck 11 is open, the elevating member 5 does not fall off the collet chuck 11.

A pressure cylinder 19 is mounted on the bracket 17.
The pressure cylinder 19 is provided at its lower end with a rod-shaped (shaft-shaped) electrode 23 provided with an electrode chip 21 so as to be detachable and replaceable.

More specifically, the vicinity of the upper part of the electrode 23 penetrates the pressurizing cylinder 19 so as to be able to move up and down. Are attached together. An electrode guide 27 for guiding the electrode 23 up and down is provided below the pressure cylinder 19.

A secondary power cable 31 which is thick and hard to bend is connected to the upper end of the electrode 23 via a swivel joint 29. One of the secondary power cables 31
The part is fixed to the bracket 17, and the connection condition of the swivel joint 29 is always kept almost constant.

When the bracket 17 and the like are moved up and down, the support plate 3 is provided with a rodless cylinder 3 as an example of a balance cylinder so as to be able to move up and down smoothly.
The upper and lower ends of a vertically movable cylinder 35 of this memberless cylinder 33 are connected to upper and lower bent portions 17U and 17L of the bracket 17, respectively. The piston is connected to the support plate 3.
Since the member-less cylinder 33 is commercially available and well-known, a detailed description of the member-less cylinder 33 will be omitted.

The memberless cylinder 33 supports the total weight of the vertically moving parts such as the elevating member 5, the bracket 17, the pressurizing cylinder 19, and the electrode 23, and constitutes a kind of weight balance device. ing. The configuration of the weight balance device is not limited to a memberless cylinder, but may be a cylinder device provided with a normal piston member. May be used. That is, the weight balance device can employ various configurations. However, a memberless cylinder is desirable in that it can cope with a change in weight (for example, a change due to replacement of an electrode tip or the like) by adjusting the air pressure and can be made compact.

In the above configuration, in order to perform spot welding of a work placed on the table, as shown in FIG. 1, after lifting the rod-shaped electrode 23, the lifting unit 5 is gripped by the clamp unit 7. It is fixed and the electrode 23 is held in a raised state.

Thereafter, the arm 1 is appropriately moved in the horizontal direction to appropriately position the electrode 23 at a desired position. Then, the gripping and fixing of the elevating member 5 by the clamp unit 7 is released so that the lifting and lowering member 5 can be moved up and down, and the electrode 23 is lowered to set the interval between the electrode tip 21 and the work at a desired interval. The lifting member 5 is gripped and fixed.

Then, after the electrode tip 21 is slightly moved in the horizontal direction so as to correspond to the spot welding position of the work and positioned, a working fluid is supplied to the pressurizing cylinder 19 to lower the electrode 23, and the electrode tip is lowered. The work is pressurized by 21 and spot welding of the work is performed by applying a welding current from the secondary power supply cable 31.

After the completion of the spot welding, the supply of the working fluid to the pressurizing cylinder 19 is switched to raise the electrode 23, and the electrode tip 21 is positioned so as to correspond to the next spot welding position. The spot welding is performed one after another by repeating the pressurization by 19 and the energization.

After the entire spot welding is completed, the gripping and fixing of the lifting member 5 by the clamp unit 7 is released, the electrode 23 is moved up to the maximum, and the lifting member 5 is again gripped and fixed by the clamp unit 7, as shown in FIG. It returns to the initial state shown in FIG.

As will be appreciated, in this example,
Since the elevating member 5 and the shaft-shaped electrode 23 are separately provided, for example, the material of the electrode 23 is made of copper, and the material of the elevating member 5 is made of iron, so that the life of the holding and fixing portion can be extended. Also,
According to the above configuration, the length of the rod-shaped electrode 23 can be reduced by an amount corresponding to the length of the elevating member 5 as compared with the configuration of the preceding example 2, and loss due to resistance can be reduced.

Further, from the secondary power cable 31 to the electrode 2
Since the power is supplied to the power supply 3 via the swivel joint 29, the contact resistance can be reduced, the loss can be reduced, and the reliability of the power supply is improved as compared with the configuration of the preceding example 2.

FIGS. 3 to 5 show a second embodiment of the present invention. The spot welding machine according to the second example includes:
Arm 1 movable horizontally as in the first example described above.
The support plate 3 is vertically provided at the tip of the support plate 3, and the elevating member 51 is supported on the support plate 3 so as to be vertically movable and fixable.

In the present embodiment, the elevating member 51 is formed in a box shape in which side walls 51B are provided on both left and right sides of a vertical front surface 51A and horizontal walls 51C are provided vertically. Then, in order to perform the vertical movement of the elevating member 51,
A rodless cylinder 53 similar to the above-described rodless cylinder 33 is disposed between the upper and lower horizontal wall portions 51C of the elevating member 51. Both ends of the cylinder 53C of the rodless cylinder 53 are vertically horizontal. It is connected to the wall 51C. And rodless cylinder 5
The piston at 3 is connected to the support plate 3.

Further, a guide member 55 is provided on the support plate 3 so that the elevating member 51 can be moved up and down smoothly.
A guide portion 57 guided up and down by 5 is provided. Further, a fixing device 59 capable of fixing the elevating member 51 so as not to move up and down is provided on the support plate 3. The fixing device 59 is provided on the side wall 5 of the elevating member 51.
1B is provided with a pair of pressing members 61A, 61B for holding at least one pressing member 61A or 61B.
B is configured to press and fix the side wall 51B to the other pressing member 61B or 61A by the action of a fluid pressure cylinder (not shown).

An L-shaped bracket 63 is attached to the lower part of the front surface of the elevating member 51.
An electrode guide 67 for guiding a rod-shaped (shaft-shaped) electrode 65 via a bush 69 so as to be vertically movable at a central portion in the left-right direction.
Is provided.

The electrode 65 penetrates the electrode guide 67 so as to be vertically movable, and an electrode chip 71 is detachably attached to the lower end of the electrode 65. Further, a handle 75 is attached at an appropriate height position of the electrode 65 via a fixing screw 73 so that the height position can be adjusted. In addition, as shown in FIG.
Is preferably circular so that it can be easily gripped even when is rotated. However, the shape does not necessarily have to be circular, but may be any shape.

One end of a secondary cable 77 connected to a power supply is connected to the upper end of the electrode 65 via a swivel joint 79. Further, a cooling water hose 81 for supplying and discharging cooling water to and from a cooling water passage (not shown) provided in the electrode 65 is connected to an upper portion of the electrode 65.

When performing spot welding of the work W on the table 83 in the spot welding machine, pressurizing cylinders 85A and 85B for pressing the electrode 65 downward are provided on the left and right sides of the electrode guide 67 with the brackets 6A and 85B.
It is attached to 3. Then, the pressurizing cylinder 85A,
Piston rods 87A, 8 provided so as to be able to move up and down at 85B
7B, an electrode holder 8 that is rotatably engaged only with a circumferential groove 65G as an engaging portion formed on the electrode 65.
9 are connected.

In the above configuration, the table 83
To perform spot welding of the workpiece W placed thereon, the lifting member 51 is lifted and raised, and then the side wall 51B is gripped and fixed by the fixing device 59, and the electrode 65 is held in the raised state.

Thereafter, the arm 1 is appropriately moved in the horizontal direction to appropriately position the electrode 65 at a desired position. Then, after the fixing of the side wall portion 51B of the elevating member 51 by the fixing device 59 is released, the electrode 65 can be moved up and down, and the electrode 65 is lowered to set the interval between the electrode chip 71 and the work W to a desired interval. The lifting member 5 by the fixing device 59
9 is again fixed so that it cannot move vertically.

Thereafter, the electrode tip 71 is slightly moved in the horizontal direction so as to correspond to the spot welding position of the workpiece, and is positioned. Then, a working fluid is supplied to the pressurizing cylinders 85A and 85B to lower the electrode 65, The spot welding of the work is performed by pressing the work W by the electrode tip 71 and applying a welding current from the secondary cable 77.

After the completion of the spot welding, the supply of the working fluid to the pressurizing cylinders 85A and 85B is switched to switch the electrodes 65
And the electrode tip 71 is positioned so as to correspond to the next spot welding position.
Spot welding is performed one after another by repeating pressurization and energization by A and 85B.

After the entire spot welding is completed, the gripping and fixing of the elevating member 59 by the fixing device 59 is released, and the electrode 6
5 is returned to the initial state by raising the maximum. The second example has the same effect as the first example.

It should be noted that the present invention is not limited to the above-described example, and can be implemented in other modes by making appropriate changes. For example, a configuration may be adopted in which a piston member is provided on a piston in a pressurized cylinder, the piston member is fixed to a bracket, and the cylinder moves up and down, and an electrode is fixed to the cylinder.

[0043]

As will be understood from the above description, the invention according to claim 1 is provided with a vertically movable and fixedly supported elevating member at the tip of an arm movable in the horizontal direction. Since the shaft-shaped electrode provided with the electrode tip at the lower end is connected to the pressurizing cylinder attached to the elevating member, the life of the elevating member and the electrode can be extended by using different materials. In addition, the length of the electrode can be shortened by an amount corresponding to the vertical dimension of the elevating member, and loss due to electrical resistance can be reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, the shaft electrode is provided so as to penetrate the pressure cylinder, and a secondary electrode is connected to the upper end of the shaft electrode via a swivel joint. Since the power cable is connected, the contact resistance can be reduced, and the reliability of power supply to the electrodes can be improved.

According to a third aspect of the present invention, in the first aspect of the invention, the shaft electrode is supported by an electrode holder provided on the pressure cylinder so as to be able to rotate only horizontally. Since the secondary power cable is connected to the portion via the swivel joint, the electrode can be easily rotated, and the directional positioning of the electrode tip provided on the electrode is easy.

According to a fourth aspect of the present invention, in the first aspect of the present invention, since the shaft-shaped electrode is provided with an annular handle, the electrode can be easily rotated and can be rotated. Even the handle is easy to hold.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an example of a main part of a spot welder according to the present invention.

FIG. 2 is an explanatory sectional view taken along line II-II in FIG.

FIG. 3 is a perspective explanatory view showing a second example of a main part of the spot welding machine.

FIG. 4 is an explanatory front view of the spot welding machine.

FIG. 5 is an explanatory plan view of the spot welding machine.

[Explanation of symbols]

 1 Arm 5 (17), 51 Lifting member 7, 59 Fixing device 9 Cylinder 11 Collet chuck 17 Bracket 19, 85A, 85B Pressing cylinder 21, 71 Electrode tip 23, 65 Electrode 29, 79 Swivel joint 31, 77 Secondary power supply Cable 33, 53 Rodless cylinder

Claims (4)

[Claims] 1. An elevating member is provided at an end of a horizontally movable arm so as to be vertically movable and fixable, and a pressure cylinder attached to the elevating member is provided with an electrode tip at a lower end. A spot welding machine characterized by connecting shaft electrodes. 2. The invention according to claim 1, wherein the shaft electrode is provided so as to penetrate the pressure cylinder, and a secondary power cable is connected to an upper end of the shaft electrode via a swivel joint. Spot welding machine characterized by the fact that there is. 3. The invention according to claim 1, wherein the shaft-shaped electrode is supported by an electrode holder provided in a pressure cylinder so as to be able to rotate only horizontally, and a swivel joint is provided at an upper end of the shaft-shaped electrode. A secondary power cable is connected via a spot welding machine. 4. The spot welding machine according to claim 1, wherein the shaft electrode has an annular handle.