JP3794002B2 - 2-stage stroke cylinder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-stage stroke cylinder used for welding guns such as C type and X type.
[0002]
Conventionally, there is a two-stage stroke cylinder used in a welding gun apparatus as shown in FIG. That is, 31 is an outer cylinder, and an inner cylinder 32 is slidably disposed on the inner periphery of the outer cylinder 31, and a first piston 34 having a piston rod 33 slides on the inner periphery of the inner cylinder 32. It is arranged so as to be movable, and the bottom of the inner cylinder 32 constitutes the second piston 35.
[0003]
A first cylinder chamber 37 is provided between the first piston 34 and the front wall 36 of the outer cylinder 31, and a second cylinder chamber 38 is further provided between the first piston 34 and the second piston 35 of the inner cylinder-32. A third cylinder chamber 40 is formed between the second piston 35 and the rear wall 39 of the outer cylinder 31.
[0004]
Further, a pressurized fluid supply / discharge passage 41 to the first cylinder chamber 37 is formed on the front wall 36, and a pressurized fluid supply / discharge passage 42 to the second cylinder chamber 38 is provided from the rear wall 39 of the outer cylinder 31 to the center of the cylinder. A pressurized fluid supply / exhaust passage 44 to the third cylinder chamber 40 is provided in the rear wall 39 in the hollow tube 43 disposed in the section. Further, the piston rod 33 provided on the first piston 34 passes through the front wall 36, and in the case of an X-type gun, its tip is at the rear end of one arm, and in the case of a C-type gun. Its tip is connected to the movable arm.
[0005]
When the piston rod 33 is advanced and retracted with a small stroke, first, pressurized fluid is supplied from the pressurized fluid supply / discharge passage 44 to the third cylinder chamber 40 and the pressurized fluid in the first cylinder chamber 37 is supplied. After discharging from the pressurized fluid supply / discharge passage 41 and moving the inner cylinder 32 forward and maintaining the tip of the inner cylinder 32 in contact with the front wall 36 (state shown), the pressurized fluid supply / discharge passage What is necessary is just to supply / discharge the pressurized fluid in the 2nd cylinder chamber 38 and the 1st cylinder chamber 37 using 42 and the pressurized fluid supply / discharge path 41.
[0006]
Also, when the piston rod 33 is advanced and retracted with a large stroke, pressurized fluid is supplied from the pressurized fluid supply / discharge passage 42 to the second cylinder chamber 38 and the third cylinder chamber 40 is added from the state shown in the figure. After the pressurized fluid is discharged from the pressurized fluid supply / discharge passage 44 and the inner cylinder 32 is retracted to bring the second piston 35 of the inner cylinder 32 into contact with the rear wall 39, the pressurized fluid supply / discharge passage is provided. What is necessary is just to supply / discharge the pressurized fluid in the 2nd cylinder chamber 38 and the 1st cylinder chamber 37 using 42 and the pressurized fluid supply / discharge path 41.
[0007]
[Problems to be solved by the invention]
By the way, in the two-stage stroke cylinder as described above, the inner cylinder 32 moves rearward when the small stroke is operated, although the pressure applied during the pressurization is only the force acting on the first piston 34. Therefore, the force that presses the second piston 35 from the rear must be larger than the force that acts on the first piston 34, and therefore the inner diameter of the inner cylinder 32 is smaller than the inner diameter of the outer cylinder 31. Must. As a result, there is a problem that the outer diameter of the outer cylinder 31 with respect to the cylinder output is increased, and the cylinder is increased in size.
[0008]
Further, the moving speed of the inner cylinder 32 when moving from the large stroke to the small stroke, that is, the moving speed of the piston rod 33 varies from the cross-sectional area of the third cylinder chamber 40 to the cross-sectional area of the first cylinder chamber 37. Since it is proportional to the subtracted value, there is a problem that if the first cylinder chamber 37 is enlarged to increase the applied pressure, the moving speed of the piston rod 33 becomes slow, and the speed of welding work cannot be increased. .
[0009]
The present invention has been made in view of such problems of the prior art, and the object of the present invention is to eliminate the movable inner cylinder and project a small-diameter cylinder in the large-diameter cylinder. By connecting each piston that slides in both cylinders to the piston rod, the diameter of the large-diameter cylinder can be reduced while increasing the applied pressure, and from the large stroke to the small stroke. It is an object of the present invention to provide a two-stage stroke cylinder that can significantly increase the speed to be shifted to (1).
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the two-stage stroke cylinder according to the present invention has a piston rod that protrudes from the rear wall of the large diameter cylinder into the large diameter cylinder and penetrates the front wall of the large diameter cylinder. Two large and small pistons sliding on the inner circumference of the large diameter cylinder and the inner diameter of the small diameter cylinder are connected in series, and the tip of the small diameter cylinder is connected to an annular piston provided between the outer circumference of the small diameter cylinder and the inner circumference of the large diameter cylinder. A stroke restricting cylinder that can project into a large-diameter cylinder ahead of the section is connected.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows a two-stage stroke cylinder according to the present invention used for, for example, a C-type welding gun. The two-stage stroke cylinder has a cylindrical side wall connecting a front wall 2 and a rear wall 3 therebetween. 4, the outer diameter of the large-diameter cylinder 1 is formed, and the small-diameter cylinder 5 projects from the rear wall 3 of the large-diameter cylinder 1 into the large-diameter cylinder 1.
[0012]
Reference numeral 6 denotes a piston rod that constitutes a pressure rod of a C-type welding gun. The piston rod 6 passes through the front wall 2 of the large-diameter cylinder 1 and an electrode is held at the tip of the piston rod 6 via an electrode holder (not shown). In addition, pistons 7 and 8 that slide along the inner periphery of the large-diameter cylinder 1 and the inner periphery of the small-diameter cylinder 5 are provided in series.
[0013]
An annular piston 9 is provided between the outer periphery of the small-diameter cylinder 5 and the inner periphery of the large-diameter cylinder 1, and the piston 9 can protrude into the large-diameter cylinder 1 ahead of the tip of the small-diameter cylinder 5. A stroke limiting cylinder 10 is connected.
[0014]
Further, an air flow passage 12 to the first cylinder chamber 11 formed between the piston 7 and the front wall 2 of the large diameter cylinder 1 is formed in the front wall 2 of the large diameter cylinder 1 and in front of the piston 7 and the small diameter cylinder 5. A pressurized fluid supply / discharge passage 15 formed between the walls 13 to the second cylinder chamber 14 passes from the side wall 4 of the large-diameter cylinder 1 through the concave portion on the outer periphery of the stroke regulating cylinder 10 to the stroke regulating cylinder. A pressurized fluid supply / discharge passage 17 to the third cylinder chamber 16 formed between the piston 8 and the front wall 13 of the small diameter cylinder 5 is formed in the body 10 on the side wall 18 of the small diameter cylinder 5. A pressurized fluid supply / discharge passage 20 to the fourth cylinder chamber 19 formed between the rear wall 3 of the diameter cylinder 1 is provided on the rear wall 3 of the large diameter cylinder 1, and the rear wall of the piston 8 and the large diameter cylinder 1. 3 is a fixed fluid supply / discharge passage 22 to the fifth cylinder chamber 21 formed between The rod 6 is formed from the vicinity of the rear surface of the piston 7 to the vicinity of the rear surface of the piston 8, and the pressurized fluid supply / discharge passage 22 in the piston rod 6 communicates the second cylinder chamber 14 and the fifth cylinder chamber 21. It is made to do.
[0015]
When the piston rod 6 is advanced and retracted with a small stroke, first, the pressurized fluid is supplied from the pressurized fluid supply / discharge passage 20 to the fourth cylinder chamber 19 and the pressurized fluid in the third cylinder chamber 16 is supplied. It is discharged from the pressurized fluid supply / discharge passage 18 and advanced until the annular piston 9 abuts against the stopper 23. During this advance, the tip of the stroke regulating cylinder 10 pushes the rear surface of the piston 7 while moving the piston rod. 6 is led to the retracted position of the small stroke (state shown). In this state, when pressurized fluid is supplied from the pressurized fluid supply / discharge passage 15 to the second cylinder chamber 14 and the fifth cylinder chamber 21 and the pressurized fluid in the third cylinder chamber 16 is discharged from the pressurized fluid supply / discharge passage 18. The piston rod 6 moves forward with a small stroke, supplies pressurized fluid from the pressurized fluid supply / discharge passage 18 to the third cylinder chamber 16, and applies pressurized fluid in the second cylinder chamber 14 and the fifth cylinder chamber 21. When discharged from the pressurized fluid supply / discharge passage 15, the piston rod 6 is retracted by a small stroke until it comes into contact with the tip of the stroke regulating cylinder 10, and is opened small.
[0016]
When the piston rod 6 is retracted with a large stroke, pressurized fluid is supplied from the pressurized fluid supply / discharge passage 18 to the third cylinder chamber 16 from the state shown in the figure, and the fifth cylinder chamber 21 and The pressurized fluid in the second cylinder chamber 14 is discharged from the pressurized fluid supply / discharge passage 15 and the pressurized fluid in the fourth cylinder chamber 19 is discharged from the pressurized fluid supply / discharge passage 20 to connect the piston rod 6 to the front wall of the small diameter cylinder 5. Retract to 13 and open.
[0017]
Since the two-stage stroke cylinder is configured as described above, when pressurized by the piston rod 6, it is added to the second cylinder chamber 14 and the fifth cylinder chamber 21 from the pressurized fluid supply / discharge passage 15 as described above. Since pressurized fluid is supplied, the piston 7 and the piston 8 are responsible for the pressure surface to the piston, and the pressure applied by the piston rod 6 is remarkably increased.
[0018]
When the piston rod 6 is shifted from the large stroke to the small stroke, as described above, the pressurized fluid is supplied from the pressurized fluid supply / discharge passage 20 to the fourth cylinder chamber 19 and the third cylinder. Since the pressurized fluid in the chamber 16 is discharged from the pressurized fluid supply / discharge passage 18 and is advanced until the annular piston 9 abuts against the stopper 23, the moving speed of the annular piston 9 at this time is This is proportional to the value obtained by subtracting the pressure receiving area of the piston 8 from the pressure receiving area. The outer diameter of the annular piston 9 is significantly larger than the outer diameter of the piston 8, and the difference in pressure receiving area between the two is particularly large. Thus, the moving speed of the annular piston 9 can be significantly increased as compared with the conventional example.
[0019]
By changing the size (length) of the stopper 23, the forward position of the annular piston 9 that contacts the stopper 23 is changed, whereby the small opening amount of the piston rod 6 when the small stroke is operated. Can be changed.
[0020]
In the above embodiment, the two-stage stroke cylinder is applied to a C-type welding gun. However, when the two-stage stroke cylinder is applied to an X-type welding gun, the piston The rod 6 may be connected to the rear end of one arm and the cylinder attached to the rear end of the other arm.
[0021]
【The invention's effect】
A two-stage stroke cylinder according to the present invention has a small-diameter cylinder projecting from a rear wall of a large-diameter cylinder into the large-diameter cylinder, and a piston rod penetrating the front wall of the large-diameter cylinder. Since two large and small pistons that slide along the inner circumference of the small diameter cylinder are connected in series, the large and small pistons will be responsible for the pressure surface to the piston during pressurization, and the pressure applied by the piston rod will increase significantly. Is done. As a result, the outer diameter of the large-diameter cylinder with respect to the cylinder output is reduced, the cylinder is miniaturized, and a desired pressure is obtained.
[0022]
Further, in addition to the above-described configuration, a stroke restriction that allows the annular piston provided between the outer periphery of the small-diameter cylinder and the inner periphery of the large-diameter cylinder to protrude into the large-diameter cylinder ahead of the tip of the small-diameter cylinder. Since the cylinders are connected, the moving speed of the piston rod when shifting from the large stroke to the small stroke is dramatically increased, resulting in a two-stage stroke cylinder that can speed up the welding operation.
[Brief description of the drawings]
FIG. 1 is a sectional view of a two-stage stroke cylinder according to the present invention.
FIG. 2 is a cross-sectional view of a conventional two-stage stroke cylinder.
[Explanation of symbols]
1 Large-diameter cylinder 2 Front wall of large-diameter cylinder 3 Rear wall of large-diameter cylinder 5 Small-diameter cylinder 6 Piston rods 7 and 8 Piston 9 Annular piston 10 Stroke regulating cylinder

Claims (1)

In a two-stage stroke cylinder where the stroke of the piston rod can be changed between a large stroke and a small stroke, a small diameter cylinder is projected from the rear wall of the large diameter cylinder into the large diameter cylinder. Two large and small pistons that slide along the inner circumference of the large-diameter cylinder and the inner circumference of the small-diameter cylinder are connected to a piston rod that passes through the front wall of the cylinder, and provided between the outer circumference of the small-diameter cylinder and the inner circumference of the large-diameter cylinder. A two-stage stroke cylinder characterized in that a stroke regulating cylinder that can project into a large-diameter cylinder ahead of the tip of the small-diameter cylinder is connected to an annular piston.

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