JPH106032A - Device for regulating height of fixed electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve pressure durability and maintainability by controlling the regulation of the height of a fixed electrode with a fluid pressure in a stud type spot welding equipment. SOLUTION: The fixed electrode 14 having a piston 4 at the lower end and installing a chip 5 at the upper end is fitted into a cylinder 2 formed in a holding member 1 so as to freely move up and down, an upper port 6a communicating to the upper chamber 2a of the cylinder 2 and a lower port 6b communicating to the lower chamber 2b are provided in the holding member 1. And an air hydro-cylinder 11 and the upper port 6a are connected by piping to an air source 8 via a variable pressure reducing valve 9 and an air switching solenoid valve 10, the air hydro-cylinder 11 is connected by piping to the lower port 6b of the cylinder 2 via hydraulic switching solenoid valve 12, or a viscous fluid or liquid is filled into the chamber before a piston 13a, and the chamber behind the piston of a cylinder 13 for ascending and descending a fixed electrode is connected by piping to the air hydro-cylinder 11 via the hydraulic switching valve 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for adjusting the height of a fixed electrode in a spot welding apparatus.

[0002]

2. Description of the Related Art Conventionally, when a spot welding gun cannot be inserted into a welding position due to a limitation of a work shape and a space in a facility with a normal spot welding gun, as shown in FIG. The movable electrode 28 (upper electrode) 28 is fixed on the base 20 and is a stud type in which the movable electrode 28 is directly attached to a pressure cylinder.

In the above-described spot welding apparatus of the stud type, it is necessary to appropriately adjust the height of the fixed electrode 23 to the position of the work W (spot), and as shown in FIG. , Guide member 2 on base 20
1 is fixed, a screw 24 is provided on the fixed electrode 23, and the screw 24 is screwed and mounted on the guide member 21.
3 is coupled to a forward / reverse rotating actuator 25 provided on the base 20, and the controller 25 controls the forward / reverse rotation of the actuator 25 to move the fixed electrode 23 up and down by the lead of the screw 24, and to detect
7, the actuator 25 is stopped when the fixed electrode 23 detects an appropriate height of the hitting point (spot) position with respect to the workpiece W to perform the adjustment.

[0004]

The above-mentioned conventional fixed electrode 2
In the height adjusting device of No. 3, since a pressure of about 300 kgf is applied during welding, the ridge of the screw 24 of the fixed electrode 23 or the ridge of the screw of the guide member 21 is damaged. Due to the backlash amount, the actuator 25 may be directly damaged by an impact load and may be damaged.

The sensor 27 and the actuator 25
It is necessary to check the process in the maintenance of the electric control mechanism of the controller 26.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fixed electrode height adjusting device in which the height adjustment of the fixed electrode is controlled by the fluid pressure, and the pressure durability and the maintainability are improved.

[0007]

According to the present invention, there is provided a stud type spot welding apparatus having a movable electrode which moves forward and backward with respect to a fixed electrode. The fixed electrode on which is mounted is fitted in a cylinder formed on the holding member in a vertically movable manner,
An upper port communicating with an upper chamber above the piston of the cylinder and a lower port communicating with a lower chamber below the piston of the cylinder are provided on the holding member, and an air source is connected to an air-hydro cylinder and an upper port of the cylinder. And a pipe is connected to the air-hydro cylinder and the lower port of the cylinder via a hydraulic switching solenoid valve.

Further, in a stud type spot welding apparatus provided with a movable electrode which moves forward and backward with respect to the fixed electrode,
A fixed electrode having a piston at the lower end and a tip mounted at the upper end is fitted in a cylinder formed on a holding member so as to be able to move up and down, and the holding member communicates with an upper chamber above the piston of the cylinder. A port and a lower port communicating with a lower chamber below the piston of the cylinder are provided, and a pipe is connected to an air-hydro cylinder and the upper port from an air source via a variable pressure reducing valve and an air switching solenoid valve. The front chamber is filled with a viscous fluid or liquid, and the rear chamber and the air-hydro cylinder of the fixed electrode lifting / lowering cylinder connected to the lower port are connected to the air-hydro cylinder via a hydraulic switching solenoid valve. It is.

[0009]

Embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a holding member of a conductive material (for example, copper) for holding the fixed electrode 14 (lower electrode). In the fixed electrode 14, a piston 4 is formed at the rear end (lower end) of the shank 3 made of a conductive material (eg, copper), and a tip 5 made of a conductive material (eg, copper) is tapered at the tip (upper end) of the shank 3. The structure is worn. Reference numeral 15 denotes a movable electrode (lower electrode) that moves up and down by a pressure cylinder (not shown) in opposition to the fixed electrode 14, and 7 denotes a tip of the movable electrode 15.

The fixed electrode 14 is provided with a cooling water circulation passage as well-known cooling means for cooling the chip 5 in the shaft of the shank 3.

A cylinder 2 is provided on the holding member 1 of the fixed electrode 14 in the vertical axis direction.
The shank 3 of the fixed electrode 14 including the piston 4 is fitted therein so as to be movable up and down.

The cylinder 2 of the holding member 1 has an upper port 6a communicating with an upper chamber 2a above the piston 4.
And a lower port 6b communicating with the lower chamber 2b below the piston 4.

A fluid pressure control device having the following configuration is connected to the upper port 6a and the lower port 6b. That is, the variable pressure reducing valve 9 and the air switching electromagnetic valve 1
0 is connected to the upper port 6a of the holding member 1 and the air-hydro cylinder 11 by piping.

The air-hydro cylinder 11 is filled with oil in the front chamber from the piston 11a.
1a, air is supplied from the air source 8 to the rear chamber by switching the air switching solenoid valve 10, and the piston 11
The hydraulic pressure is generated by pressing the oil in the front chamber from a.

A fixed electrode lifting / lowering cylinder 13 is connected to the lower port 6b of the holding member 1 by piping. The fixed electrode lifting / lowering cylinder 13 includes a piston 13
a is filled with a viscous fluid (for example, conductive grease) or a liquid (for example, oil or water), and the front chamber is filled with the viscous fluid or liquid. Is connected to the piping.

A pipe is connected to a chamber behind the piston 13a of the fixed electrode lifting / lowering cylinder 13 via the air-hydro cylinder 11 and a hydraulic switching electromagnetic valve 12, and the hydraulic switching electromagnetic valve 12 is switched by the piping. The hydraulic pressure generated by the air-hydro cylinder 11 is supplied to the rear chamber from the piston 13a of the fixed electrode lifting / lowering cylinder 13, and the viscous fluid or liquid filled in the front chamber of the fixed electrode lifting / lowering cylinder 13 is supplied to the lower port of the holding member 1. 6b
The viscous fluid or liquid press-fitted into the lower chamber 2b of the cylinder 2 is blocked by switching the hydraulic switching solenoid valve 12 from above.

When a viscous fluid (for example, conductive grease) is used, the fixed electrode lifting / lowering cylinder 13 is connected to the lower chamber 2b of the cylinder 2. However, the fixed electrode lifting / lowering cylinder 13 is eliminated and the air-hydro cylinder 11 is used. May be connected directly to the lower port 6b of the cylinder 2 via a hydraulic switching solenoid valve 12.

The operation of the apparatus according to the present invention having the above configuration will be described with reference to FIGS. FIG. 2 shows the fixed electrode 1
4 is a return state. In this state, the air switching solenoid valve 10
, The air source 8 communicates with the upper port 6a of the holding member 1, air is supplied to the upper chamber 2a of the cylinder 2 of the holding member 1, and the fixed electrode 14 is pushed to the lower end.

Further, the rear chamber of the air-hydro cylinder 11 is brought into the atmospheric pressure state by communicating with the atmosphere by the switching of the air switching solenoid valve 10.

Further, the hydraulic switching solenoid valve 12 is provided between the rear chamber of the fixed electrode lifting / lowering cylinder 13 and the air-hydro cylinder 11.
Has been switched to a state in which it communicates with the front chamber.

Therefore, the viscous fluid or liquid press-fitted into the lower chamber 2b of the cylinder 2 of the holding member 1 in the previous height adjustment is pushed from the lower port 6b to the fixed electrode 14 by pushing the fixed electrode 14 to the lower end. It is pushed back to the front chamber of the lifting cylinder 13.

After the work W is set above the fixed electrode 14 in the above-mentioned fixed electrode 14 return state, the air switching solenoid valve 10 is connected to the air source 8 and the air-hydro cylinder 11 as shown in FIG. , Cylinder 2 of holding member 1
The upper chamber 2a is switched to communicate with the atmosphere. At this time, the hydraulic switching solenoid valve 12 is
And the front chamber of the air-hydro cylinder 11 is maintained in a switched state.

As a result, the hydraulic pressure is supplied from the air-hydro cylinder 11 to the rear chamber of the fixed electrode lifting / lowering cylinder 13, and the piston 13a of the fixed electrode lifting / lowering cylinder 13 moves forward and viscous fluid filled in the front chamber. The liquid is pressed into the lower chamber 2b of the cylinder 2 of the holding member 1 from the lower port 6b, and the pressure raises the fixed electrode 14 to abut the chip 5 on the lower surface of the work W, thereby increasing the height of the fixed electrode 14. It is adjusted according to the work W.

At this time, the pressure of the viscous fluid or liquid in the lower chamber 2b of the cylinder 2 of the holding member 1 is about 3 to 4 kgf / cm ^{2 when} the diameter of the piston 4 is 20φ. The contact pressing force is about 10 kgf.

By adjusting the pressure of the air supplied to the air-hydro cylinder 11 by means of the variable pressure reducing valve 9, the height of the fixed electrode 14 up to the hitting position of the work W and the contact pressing force against the work W are reduced. Adjusted.

After the height of the fixed electrode 14 is adjusted according to the work W, the movable electrode 15 is lowered by a pressure cylinder (not shown) to press the upper surface of the work W as shown in FIG. At this time, the air switching electromagnetic valve 10 holds the switching state at the time of the height adjustment, but the hydraulic switching electromagnetic valve 12
Is switched to a block position in which the air-hydro cylinder 11 and the fixed electrode lifting / lowering cylinder 13 are disconnected.

Accordingly, the viscous fluid or liquid pressed into the lower chamber 2b of the cylinder 2 of the holding member 1 is sealed in the lower chamber 2b of the cylinder 2 of the holding member 1, and the fixed electrode 14 is The viscous fluid or liquid, which holds the adjusted height and is sealed in the lower chamber 2b of the cylinder 2 of the holding member 1, buffers the pressurizing impact of the movable electrode 15 to spot weld the work W. I do.

After the spot welding of the workpiece W, the fixed electrode 14 is returned to the return state as shown in FIG. 2, and the spot welding cycle is completed.

The same operation as described above can be obtained even when the air-hydro cylinder 11 is directly connected to the lower port 6b of the cylinder 2 via the hydraulic switching solenoid valve 12 by piping.

[0030]

As described above, according to the present invention, a fixed electrode having a piston at a lower end and a tip mounted at an upper end is fitted into a cylinder formed on a holding member so as to be movable up and down, and the holding member is An upper port communicating with an upper chamber above the piston of the cylinder and a lower port communicating with a lower chamber below the piston of the cylinder, and a variable pressure reducing valve from an air source to the air-hydro cylinder and the upper port. The air-hydro cylinder was connected to the lower port of the cylinder via a hydraulic switching solenoid valve, or a viscous fluid or liquid was filled in the front chamber from the piston and connected to the lower port. Since the fixed electrode lifting / lowering cylinder has a configuration in which a rear chamber of the piston and the air-hydro cylinder are connected to the air-hydro cylinder through a hydraulic pressure switching valve, the fixed electrode is fixed. For it controlled by the height of all adjustment fluid pressure of the electrodes, and has a conventional mechanical advantage to improve the example pressure durability and integrity than the adjustment.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the apparatus of the present invention.

FIG. 2 is a sectional view of a fixed electrode in a returned state.

FIG. 3 is a cross-sectional view showing a state in which the height of a fixed electrode is adjusted.

FIG. 4 is a cross-sectional view of a pressurized state by a movable electrode.

FIG. 5 is a sectional view of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Holding member 2 Cylinder 2a Upper chamber 2b Lower chamber 3 Shank 4 Piston 5 Tip 6a Upper port 6b Lower port 7 Chip 8 Air source 9 Variable pressure reducing valve 10 Air switching solenoid valve 11 Air-hydro cylinder 11a Piston 12 Hydraulic switching solenoid valve 13 Fixed electrode lifting cylinder 13a Piston 14 Fixed electrode 15 Movable electrode

Claims (2)

[Claims] 1. A stud type spot welding apparatus provided with a movable electrode which moves forward and backward with respect to a fixed electrode, wherein a fixed electrode having a piston at a lower end and a tip mounted at an upper end is placed in a cylinder formed on a holding member. The holding member is provided with an upper port communicating with an upper chamber above the piston of the cylinder and a lower port communicating with a lower chamber below the piston of the cylinder. A pipe is connected to an upper port of the cylinder from an air source via a variable pressure reducing valve and an air switching solenoid valve, and a pipe is connected to the air-hydro cylinder and the lower port of the cylinder via a hydraulic switching solenoid valve. Fixed electrode height adjustment device. 2. A stud type spot welding apparatus having a movable electrode which moves forward and backward with respect to a fixed electrode, wherein a fixed electrode having a piston at a lower end and a tip mounted at an upper end is placed in a cylinder formed on a holding member. The holding member is provided with an upper port communicating with an upper chamber above the piston of the cylinder and a lower port communicating with a lower chamber below the piston of the cylinder. A pipe is connected to the upper port of the cylinder from an air source via a variable pressure reducing valve and an air switching solenoid valve, and the front chamber is filled with a viscous fluid or liquid from a piston, and the fixed electrode lifting / lowering cylinder connected to the lower port is connected to the lower port. The height adjustment of the fixed electrode, characterized in that the rear chamber from the piston and the air-hydro cylinder are connected by piping via a hydraulic switching solenoid valve. apparatus.