JPH0742673U - Spot welder - Google Patents

Abstract

(57) [Summary] [Purpose] Achieving weight and compactness by unitizing the components of the spot welding machine. [Structure] An arm portion supporting one electrode of a resistance welding machine for welding by energizing and welding an object to be welded between electrodes and a support portion of a pressure actuator for driving the other electrode have the same structure, The actuator is provided on the rear surface of the body structure,
In addition, a conductive member having a degree of freedom in the direction of linear movement by the actuator is arranged as an energizing secondary circuit in the internal space of the body structure section, and an equalizing shaft is installed so as to straddle both sides of the body structure section. The crotch bracket supported on the robot side, which is movably guided and supported, is arranged. By doing so, in particular, the weight and size of the robot gun that uses an electric motor as a pressure source for the electrode can be reduced and the work efficiency of the assembly and maintenance of the gun parts can be dramatically improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a spot welding machine in which components such as an electrode pressing device, an equalizing mechanism, and a secondary conductor are unitized.

[0002]

[Prior art]

 Conventionally, fluid pressure cylinders are generally used in large numbers as the pressure source for the electrodes of spot welders. Especially for robot guns, the size of the entire gun is a problem in order to be able to hit welds even in narrow welding positions.

[0003]

[Problems to be solved by the device]

 The problem to be solved by the present invention is that, in the case where the air cylinder is used as the drive source of the pressurizing actuator, not only the air valve and the piping are arranged outside the gun body, but also the equalizing mechanism is provided on both sides of the air cylinder. This is because the outer width of the gun spreads widely because it is placed, and it was not possible to make the entire gun a slim structure.

Therefore, the present invention has a structure in which the shunt on the side of the point holder is housed inside the arm and the equalizing mechanism is arranged on both sides of the arm to minimize the external dimensions of the conventional robot welding gun. The purpose is to reduce the load on the robot by reducing the weight and weight, and to shorten the work time for parts assembly and maintenance of the gun body.

[0005]

[Means for Solving the Problems]

 The present invention takes the following technical means in order to achieve the above object.

That is, in a resistance welding machine that welds a workpiece by pressurizing and energizing it between electrodes, an arm portion that supports one electrode and a support portion of a pressure actuator that drives the other electrode are provided. The same structure is used, the actuator is arranged on the back surface of the same structure part, and the conductive member having a degree of freedom in the linear motion direction of the actuator is arranged as an energizing secondary circuit in the inner space of the same structure part. A crotch bracket supported on the robot side is movably guided and supported via an equalizing shaft so as to straddle both sides of the body structure.

The actuator uses an electric motor as a drive source thereof. The actuator includes an electrode drive shaft that incorporates a ball screw into a ball nut, which converts the rotational force of the motor into a reciprocating linear motion, and the motor. It consists of a power transmission mechanism that transmits power to the electrode drive shaft, and it is a unit that is attached to the back of the structural body.

A water cooling hose forming a cooling water path to the electrode is arranged along the outside of the loop of the conductive member.

[0009]

[Action]

 Further, according to the present invention, the pressure actuator is removably arranged on the rear surface of the same structural part by unitizing the components such as the electrode pressure device, the equalizer device, and the secondary conductor that constitute the resistance welding machine. Moreover, the equalizing unit can be easily removed from the crotch bracket that is arranged so that the gun body sandwiches the same structure by pulling out the equalizing shaft to the electrode side. Further, since the water cooling hose is arranged along the outside of the loop of the conductive member, the water cooling pipe does not spread to both sides of the gun body. Therefore, by combining these, the work efficiency of assembling and maintaining the gun parts is dramatically improved, and the weight and size of the gun are reduced.

[0010]

【Example】

 FIG. 1 is a side view showing an embodiment of the device of the present invention. FIG. 2 is a plan view. FIG. 3 is a view on arrow AA of FIG.

FIG. 1 shows a C type robot gun. Reference numeral 2 is a structural body of the gun body. In this structure, the support portion 2a of the pressure actuator 3 and the arm portion 2b supporting one electrode are integrated.

Reference numeral 4 is an equalizing shaft whose both ends are fixed to the body structure side. The equalizer shafts 4 are arranged on both sides of the body structure part. _It is attached by ₄ and the rear part is attached by bolt B ₅ to the base attachment plate 2d of the same structural part. Reference numeral 5 is a crotch bracket. This crotch bracket has a bearing through which the equalizing shaft 4 penetrates, and supports the entire gun so as to perform an equalizing operation. A robot mounting seat 6 is provided on the bracket 5, and a robot arm (not shown) is connected to the seat surface. A welding transformer 7 is fastened and fixed to the upper portion of the bracket 5 with four bolts B ₁ .

Reference numeral 8 denotes a base of the actuator 3. The actuator is configured as a unit so that it can be attached to the same structural part 2 of the main body in common with various gun variations so as to cope with robot gun variants. The base 9 is fixed by tightening a plurality of bolts B ₂ from the back surface of the arm.

The base 8 may be divided into an electrode driving shaft 10 and an electric motor 11 so that the timing belt tension can be set, as shown in FIG. It may be an integral body having a size such that the electric motor 11 can be attached together.

An electric motor 11 and an angular bearing 12 are fixed to the base 8. Electrostatic dynamic motor 11 outputs a rotational force as a pressurization source electrode, also angular bearing 12 is used to convert the rotational output of the motor 11 into reciprocating linear motion, by a bolt B ₃ to the base 8 It is composed of a fixed housing of the angular bearing 12 and a ball nut (not shown in the figure) that allows smooth rotational movement through the angular bearing in the bearing. The electrode drive shaft 10 that is converted into a linear motion is constructed by incorporating a ball screw into a ball nut, for example.

In the case of the present embodiment, the power transmission mechanism is such that the belt gear 13 and the belt gear 14 attached to the output shaft of the motor 11 and the ball nut are arranged in the thickness direction (plate width e) of the base 8. The timing belt 15 is incorporated within the size and the timing belt 15 is stretched between the two gears. The rotational force of the electric motor 11 rotates the ball nut via the timing belt 15 to give the ball screw 10 a linear motion.

A bearing 16 incorporated into a ball screw such as a ball spline and a bearing 17 fixed to the housing side are attached to both sides of the base 8. The bearing 16 and the bearing 17 guide the ball screw 10 from both sides of the base and also have a rotation preventing function. Reference numeral 18 denotes an electrode fixed to the tip of the electrode drive shaft via a point holder 19. Reference numeral 20 is an electrode fixed to the tip of the arm. Reference numerals 21 and 22 denote shunts forming a secondary circuit for energizing each electrode.

The shunt 21 is a conductive member which is arranged in the space of the structural body and is made of a flexible U-shaped copper plate that is movable in the linear movement direction of the electrode drive shaft 10 with a degree of freedom. Reference numeral 23 is a cooling water hose which is arranged so that a loop is wound around the U-shaped outer side of the shunt 21. This hose 21 is piped from the IN or OUT side port of the cooling manifold 26 of the secondary bus bar 25 attached to the secondary terminal 24 of the welding transformer 7 to the point holder 19.

Although not shown in the drawing, the cooling water hose is also connected to the other shunt 22 so that a loop is wound around the outside of the U-shape so that the entire width of the gun is minimized. Is being treated. In this case, the secondary side bus bar 27 attached to the other secondary terminal side is piped from the IN or OUT side port of the cooling manifold to the arm side bus bar.

In the device of the present invention having such a configuration, the electrode drive shaft 10 including the electric motor 13 and the ball screw is attached to the upper side of the base 8, and the bearing 19 of the electrode drive shaft 10 is fixed to the lower side of the base. Therefore, if the base 8 is removed from the gun arm 2 of the gun body, the entire electrode pressurizing unit can be completely pulled out backward.

When the timing belt 15 is replaced, the electric motor 11 is removed with the belt gear 13 and the belt gear 14 still attached, and the bolt B ₂ of the housing of the angular bearing 12 of the ball nut is loosened and displaced rearward. Through this gap, the timing belt 15 can be pulled out backwards through the housing. When checking the tension of the timing belt 15, use a measuring tool from the belt measurement opening 28 provided in the base, or measure the backward movement between the housing of the angular bearing 12 of the ball nut and the electric motor 11. You can check it from. Also, when the base is divided into two, it can be confirmed from the gap between the bases.

Further, the secondary busbar 25 and the secondary busbar 27 are removed from the secondary terminals of the welding transformer, or the shunt 21 and the shunt 22 are removed from these busbars respectively, and the bolt B ₄ and the bolt B _{4 are} removed. Loosen B ₅ and remove the equalize shaft 4 from the arm side support so that the gun body looks exactly the same and the crotch bracket 5 can be removed. In this way, there is no need to remove the bracket from the robot, so there is no need to redo teaching (positioning) after mounting the gun.

[0023]

[Effect of device]

 As described above, according to the device of the present invention, the pressurizing unit, the gun body, the equalizing device, the secondary conductor (including the cooling water hose), etc. are configured as unit parts, and the pressurizing actuator is It is removably placed on the back side of the body structure, and the equalizer unit can be easily removed from the crotch bracket arranged so that the gun body sandwiches the body structure by removing the equalize shaft from the body side. Further, since the water cooling hose is arranged along the loop of the conductive member, the water cooling pipe does not spread to both sides of the gun body. Therefore, by combining these, the parts of the gun can be easily rearranged and maintained, the entire gun can be minimized, and the weight and cost can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a side view of the entire welding gun showing an embodiment in which the device of the present invention is applied to a robot gun for spot welding.

FIG. 2 is a rear view of the device of the present invention. .

FIG. 3 is a view on arrow AA of FIG.

[Explanation of symbols]

1 Spot Welder (Robot Gun) 12 Angular Bearing 2 Body Structure Section 13 Belt Gear 3 Pressure Actuator 14 Belt Gear 4 Equalize Shaft 15 Timing Belt 5 Crotch Bracket 16 Bearing 6 Robot Mounting Seat 17 Bearing 7 Welding Transformer 18 Electrode 8 Base 19 Point holder 10 Electrode drive shaft (ball screw) 20 Electrode 11 Electric motor 21 Shunt 23 Cooling water hose 22 Shunt 24 Secondary terminal 25 Secondary side bus bar 26 Cooling manifold 27 Secondary side bus bar

Claims (3)

[Scope of utility model registration request] 1. In a resistance welding machine for welding an object to be welded under pressure by energizing the object to be welded, an arm portion for supporting one electrode and a support portion for a pressure actuator for driving the other electrode are integrally structured. The actuator is arranged on the back surface of the solid structure part, and a conductive member having a degree of freedom in the linear movement direction of the actuator is arranged as an energization secondary circuit in the internal space of the solid structure part, and the solid structure part is formed. A spot welder, which has crotch brackets supported on the robot side that are movably guided and supported via an equalizing shaft so as to straddle it on both sides. 2. The equalizing shaft passes through a bearing of the crotch bracket and is detachably connected to the body structure side so as to be taken out to the electrode side while leaving the crotch bracket. Spot welder. 3. A water cooling hose forming a cooling water path to an electrode is arranged along a loop line of the conductive member.
Or 2 spot welders.