JP2569402Y2 - Pressure cylinder for welding machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressurizing cylinder for a welding machine in which a piston is slidably disposed on the inner periphery of a cylinder and a pressurizing rod fixed to the piston extends from the piston. It is.

[0002]

2. Description of the Related Art Conventionally, a pressurizing cylinder used in a resistance welding machine or the like usually has a piston slidably disposed on the inner periphery of the cylinder, and a pressurizing rod fixed to the piston extends from the piston. Then, the piston is slid forward, and a work is sandwiched between the electrode at the tip of the pressure rod and the other electrode for welding. When the welding operation is performed, the piston is slid backward by discharging the pressurized fluid acting on the rear surface of the piston, but the rear surface of the piston suddenly collides with the front surface of the cylinder rear wall during this retreat. In many cases, the impact force causes the entire pressurizing cylinder to vibrate violently.

Therefore, it is conceivable to provide an appropriate shock absorber between the rear surface of the piston and the front surface of the cylinder rear wall. As means therefor, there are a method of damping by elastic force of rubber or a spring and a method of damping steel plate (for example, see Japanese Utility Model Application No. 2-105290).

[0004]

However, in the case of using rubber or spring, when the elastic force is weakened due to fatigue of the material due to long-term use and the intended purpose cannot be achieved or these cushioning members are damaged. In such a case, the debris may enter the sliding surface of the piston and render the pressurizing cylinder itself unusable.

When a damping steel sheet is used, the shock is absorbed by the damping steel sheet, so that the damping steel sheet itself becomes fatigued and is not suitable for long-term use. In addition, there is a problem that the damping steel sheet may not completely absorb the impact force.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to use a poppet valve to cushion a residual fluid and to use the cushioning function and a magnet. By using the repulsive force of the above, the rear surface of the piston does not collide with the front surface of the cylinder rear wall. Things.

[0007]

To achieve the above object, a pressurizing cylinder for a welding machine according to the present invention comprises a pressurized fluid supply passage having a check valve and a poppet valve in a rear wall of the pressurizing cylinder. A pressurized fluid discharge passage having a pressure cylinder, a protrusion formed on the back surface of the piston of the pressure cylinder, and a T-shaped push rod operated by the protrusion to forcibly close the poppet valve. A flow path disposed in a recess on the front surface of the wall and bypassing the pressurized fluid supply path upstream of the check valve is communicated with a front chamber of the poppet valve cylinder. .

[0008]

In the pressurized cylinder for a welding machine constructed as described above, when the pressurized fluid, for example, pressurized air is supplied to the front chamber of the piston in order to retreat the piston when the welding operation is completed, And the poppet valve is opened, and the pressurized fluid in the rear chamber of the piston is discharged from the discharge passage. When the piston moves for a predetermined stroke, the protrusion on the back surface of the piston approaches the T-shaped push rod, pushes the poppet valve with the push rod, moves the poppet valve, and moves the pressurized fluid discharge passage. Close. Therefore, the pressurized fluid remaining in the rear chamber of the piston is compressed to perform a cushioning action for preventing the piston from retreating, so that the piston does not collide with the cylinder. As a result, no impact force is generated on the rear wall by the piston as in the conventional example.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 denotes a pressurizing cylinder for a welding machine. The cylinder 1 comprises a cylinder body 2 and a lid 3 constituting a rear wall of the cylinder 1. A piston 4 slides inside the cylinder body 2. A fixed arm (not shown), which is movably held and has an electrode (not shown) at the tip, is fixed thereon. A pressure rod 5 having another electrode (not shown) at the tip is fixed to the piston 4. A projection 7 is formed on the back surface 6 of the piston 4.

A fluid supply passage 9 for supplying a pressurized fluid to the rear chamber 8 of the piston 4 is formed in the lid 3 constituting the rear wall, and a check valve 10 is disposed in the middle of the fluid supply passage 9. Have been. Further, a fluid discharge passage 11 for discharging pressurized fluid from the rear chamber 8 of the piston 4 is formed in the lid 3, and a poppet valve cylinder 12 is provided in the middle thereof. A piston portion 14 of a poppet valve 13 is slidably disposed in the poppet valve cylinder 12, and a fluid passage 15 is formed in a stem portion of the poppet valve 13. The fluid passage 15 can communicate with a rear chamber 16 of the poppet valve cylinder 12 and a rear end thereof communicates with an outlet opening of a fluid discharge passage. A front chamber 17 of the poppet valve cylinder 12 communicates with a bypass pipe 18 on the upstream side of the check valve 10 in the fluid supply path 9, and a rear chamber 16 of the poppet valve cylinder 12 is provided.
Communicates with the middle of the fluid discharge path 11.

Further, on the front surface of the lid 3 constituting the rear wall,
A recess 19 is formed at a position facing the protrusion 7 of the piston 6, and a T-shaped push rod 20 is movably disposed in the recess. And the trunk 2 of the T-shaped push rod 20
1 is a front wall 2 of the poppet valve cylinder 12.
4 and a stopper 23 made of a snap ring is provided near the tip 22 of the poppet valve 13 in the poppet valve cylinder 12. The stopper 23 is used to move the poppet valve cylinder 1 when the T-shaped push rod 20 advances.
The T-shaped push rod 20 is prevented from jumping out of contact with the front wall 24 of the second.

In this embodiment having the above-described structure, in the state shown in FIG.
When the pressurized air in the front chamber 26 of the cylinder is discharged from the pressurized air passage 25 through the pressurized air
Is supplied to the front chamber 17 in the poppet valve cylinder 12 via the bypass pipe 18, and a part of the pressurized air is supplied to the pressurized air from the rear chamber 8 via the discharge pipe 11. The pressure rod 5 is also supplied to the rear chamber 16 in the valve cylinder 12, so that the pressure rod 5 advances toward the work (not shown) and sandwiches the work between the electrodes (not shown). The work is welded in this state (see FIG. 2).

When the welding operation is completed, the pressurized air is supplied from the pressurized air passage 25 to the front chamber 26 of the cylinder from the state shown in FIG. 8, the pressure increases from the rear chamber 16 in the poppet valve cylinder 12 to the piston portion 14.
To move the poppet valve 13 forward to
Communicates with the rear chamber 16 in the poppet valve cylinder 12. The air in the front chamber 17 in the poppet valve cylinder 12 is discharged via the bypass pipe 18 by the advance of the poppet valve 13. Accordingly, the poppet valve 13 is in the state shown in FIG. 3, and the pressurized air in the rear chamber 8 of the cylinder is discharged from the fluid discharge passage 11 through the fluid passage 15 of the poppet valve 13 as the piston 4 retreats.

When the projection 7 comes into contact with the front surface of the T-shaped push rod 20 in the recess 19 as the piston 4 retreats,
The protrusion 7 pushes the T-shaped push rod 20 and retreats, and the tip 22 of the T-shaped push rod 20 pushes the piston portion 14 of the poppet valve 13 to retreat the poppet valve 13. Then, the discharge of the pressurized air from the rear chamber 8 of the cylinder is stopped. As a result, the air pressure in the rear chamber 8 of the cylinder rises and acts as a cushion to prevent the piston 4 from retreating.
Is prevented from colliding with the lid 3 serving as the rear wall.

When magnets 27 and 28 having the same polarity are provided on the rear surface of the protrusion 7 and the front surface of the T-shaped push rod 20, the protrusion 7 is disposed on the front surface of the T-shaped push rod 20 as the piston 4 retreats. Before contact, a repulsive force acts on the magnets, and the T-shaped push rod 20 moves toward the poppet valve 13 due to the repulsive force.
The poppet valve can be closed. Therefore, in this case, the impact of the piston 4 on the lid 3 can be further reduced.

[0016]

Since the present invention has the above-described structure, when the welding operation is completed and the pressure rod is retracted, the pressure rod is rapidly retracted at first, and the protrusion on the back surface of the piston is formed. Abuts on the T-shaped push rod, the push rod closes the poppet valve and raises the fluid pressure in the rear chamber of the cylinder, so that the fluid acts as a cushion. The collision of the pressure cylinder for a welding machine for a welding machine, which can withstand a long-term use and is not likely to be damaged without a shock, unlike the conventional example, is avoided since no impact force is generated unlike the conventional example. Device.

In the second aspect, the magnets having the same polarity are provided on the rear surface of the protruding portion and the front surface of the T-shaped push rod. As a result, since no impact force is further generated, the shock absorber of the pressure cylinder for a welding machine can be used for a longer period of time without any risk of breakage.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a shock absorber of a pressurizing cylinder for a welding machine according to the present invention when the shock absorber is cushioned.

FIG. 2 is a side sectional view of the shock absorber in the pressurizing cylinder for a welding machine according to the present invention when pressurized fluid is supplied.

FIG. 3 is a side sectional view of the shock absorber in the pressurizing cylinder for a welding machine according to the present invention when the pressurized fluid is discharged.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pressurizing cylinder 2 cylinder body 3 rear wall 4 piston 5 pressurizing rod 7 protrusion 9 pressurized fluid supply path 10 check valve 11 pressurized fluid discharge path 12 cylinder for poppet valve 13 poppet valve 18 bypass flow path 19 recess 20 T-shaped push rod 27, 28 magnet

Claims (2)

(57) [Scope of request for utility model registration] In a pressurizing cylinder for a welding machine, a piston is slidably disposed on the inner periphery of a cylinder, and a pressurizing rod fixed to the piston extends from the piston. A pressurized fluid supply path having a check valve and a pressurized fluid discharge path having a poppet valve cylinder are provided in the wall, and a projection is formed on the back surface of the piston of the pressure cylinder, and the projection is operated by the projection. A T-shaped push rod forcibly closing the poppet valve is disposed in the recess on the front surface of the rear wall,
A pressurizing cylinder for a welding machine, wherein a flow path bypassing the pressurized fluid supply path is connected to a front chamber of the poppet valve cylinder on an upstream side of the check valve. 2. The pressurizing cylinder for a welding machine according to claim 1, wherein magnets having the same polarity are disposed on a rear surface of the projecting portion and a front surface of the T-shaped push rod.