JPH11111492A - Non-shifting type swinging plasma torch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To swing high temperature gas flames without diffusing or cooling the flames by forming an aperture of which a part is enters into the inner space of a nozzle stand and which is aligned with the center axial line of an electrode in one end face, forming an aperture made eccentric from the center axial line of the electrode in end face in the outside of an inner hollow, and installing a plasma nozzle communicating both apertures. SOLUTION: Plasma arc is generated between the tip end of an electrode 20 and the inner surface of the plasma nozzle 52 of a nozzle member 50, ionizes plasma gas which passes through a nozzle 52, and blows out of an outer aperture 51. Plasma flames are jetted out at a certain angle to the center axis 21 since the outer aperture 51 is made eccentric to the center axis 21. When an electric motor 70 is driven, the nozzle member 50 is rotated and driven and consequently, the outer aperture 51 is moved while drawing a circle on the center axis 21 and the plasma flames jetted out of the outer aperture 51 move as to draw conical face on the center axis 21. As a result, processing is carried out with uniform heat distribution in a wide range by one scanning within a range of plasma flame radiation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-transfer type plasma torch for injecting high-temperature gas into plasma by arc discharge.

[0002]

2. Description of the Related Art A torch of this type is used for high-temperature processing or processing of an object, and is used for heating, melting, thermal spraying and the like of metal. Plasma jet frames exhibit a heat distribution in which the temperature is very high in the center and drops rapidly toward the outside of the frame. However, when a thin steel plate is subjected to surface heating treatment or the like, it is easily melted by the heat of the central portion, and in order to avoid this, an arc is oscillated at high speed and a wide and uniform plasma jet heat source is required. For this reason, the non-transfer type plasma torch disclosed in Japanese Patent Application No. 3-40273 generates a magnetic flux in a direction crossing an arc current path in the torch with an electric coil, and the arc current and the acting force of the magnetic flux cause an arc. Swings the current. According to this, the arc current deflects and fluctuates, but the high-temperature gas frame has a strong directivity (inertial force) on the torch axis, is unable to move heat in the deflection direction, and has a temperature distribution on the torch axis. Will be higher. Further, since the anode point of the arc on the outer electrode is forcibly reciprocated, the copper of the outer electrode is quickly consumed, and there is a problem that fine particles which are melted and scattered of the copper are deposited on the surface of the workpiece.

In the non-transfer type plasma jet apparatus disclosed in Japanese Patent Application No. 4-31886, a oscillating gas is applied to a plasma jet frame in a direction crossing the plasma jet frame, and the direction and intensity of the oscillating gas are continuously changed. To swing the plasma jet flame. According to this, since the high-temperature gas frame is shaken by the oscillating gas, the oscillating effect is high. However, since a low-temperature oscillating gas is blown onto the plasma frame, the temperature of the plasma jet frame decreases. In addition, since the plasma frame is swung by the strength of the swinging gas, high-speed swinging is impossible.

The oscillating plasma torch disclosed in Japanese Patent Application Laid-Open No. 9-164486 has a nozzle member for injecting plasma having a nozzle whose plasma injection opening is eccentric, and this nozzle member is rotated by an electric motor. Drive. As an example, a transfer type plasma torch is disclosed. This transfer type plasma torch is suitable for fillet welding, in which a plasma jet rotates so as to draw a conical surface, and a plasma action area is wide with respect to a welding material to which the plasma is transferred. Even if the position is slightly shifted, the plasma arc acts on the intended place. Welding with long leg lengths and welding with large joint gaps are possible. However, the transfer-type plasma torch of this embodiment is intended for local heating, such as welding, even if the plasma jet is swung to apply a plasma arc to a wide area. Is small before and after the groove, and the arc current is relatively low, for example, about 250 A or less.

However, in the heating and thermal spraying of a steel material by a non-transfer type plasma torch, there are many uses in which a high current value of 300 A or more, for example, 500 A or 800 A, is used. It is desired to spray at high speed. In this case, the swing type plasma torch specifically disclosed in Japanese Patent Application Laid-Open No. 9-164486,
Electrodes are easily overheated, and the nozzle cooling effect is low.
It is presumed that cooling measures are required.

[0006]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a non-transfer type plasma torch in which a high-temperature gas frame is swung without being diffused or cooled, and a high-speed swinging is performed. A second object is to provide a non-transferring oscillating plasma torch suitable for a high current value. A third object is to provide a non-transferring oscillating plasma torch which is easy to inspect and maintain a rotary drive mechanism. And a fourth object.

[0007]

Means for Solving the Problems (1) The non-transferring oscillating plasma torch of the present invention has an insulating spacer (10) having a relatively large through hole (11) at the center;
An electrode (20) penetrating the through hole (11); the insulating spacer
(10) An electrode base fixed to the rear end and supporting the electrode (20)
(30); a nozzle base (40) having an inner space (41) for receiving the electrode (20) and fixed to an end of the insulating spacer (10) on the nozzle side, that is, a tip; Nozzle base (40) inner space (4
1), the opening (53) aligned with the center axis (21) of the electrode (20) on the end face (54), and the center of the electrode (20) on the end face outside the inner space of the nozzle base. Opening (5) eccentric from axis (21)
1), a plasma nozzle (52) connected to both openings (53, 51), and the nozzle table (40) has a central axis (21) of the electrode (20).
Nozzle member (50) rotatably connected to a fluid seal (55, 54) about the nozzle member; the nozzle member (50) is provided outside of the nozzle table in order to rotationally drive the nozzle member (50). A rotary drive mechanism (60) mounted on the portion; and a motor (70) for applying a rotary torque to the rotary drive mechanism (60) to rotationally drive the nozzle member (50). In addition, in order to facilitate understanding, the symbols of the corresponding elements in the embodiments shown in the drawings and described later are added in the parentheses for reference.

According to this, the prime mover (70) is a rotary drive mechanism.
When a rotational torque is applied to (60), the nozzle member (50)
It rotates about the center axis (21) of (20). As a result, the electrode-side opening (53) to which the plasma nozzle (52) is connected rotates around the center axis (21) of the electrode (20), but the center axis (2) is always
A plasma arc, which is aligned with (1) and faces the electrode (20) and continues to the tip of the electrode (20), passes through substantially the center (21) of the opening (53). However, the outer end face opening (51) where the plasma nozzle (52) continues
Is eccentric from the center axis (21), so the center axis (21)
Draw a circle around. Therefore plasma nozzle (52)
The plasma frame spouting out of the cylinder rotates so as to draw a conical surface about the central axis (21). in this way,
Since the plasma frame rotates so as to draw a conical surface due to the mechanical rotation of the nozzle member (50), there is no diffusion or cooling in the case where the plasma frame is shaken by an air current as in the prior art, and the plasma frame is not cooled. The system surely advances in the direction in which the outer end opening (51) is directed. The mechanical rotation of the nozzle member (50) can be performed at high speed, and the plasma jet frame can be rotated and oscillated at high speed. The rotation drive mechanism (60) is a nozzle member (50)
Because it is attached to the part outside the nozzle base,
H is not easily affected by the internal heat, and inspection and maintenance are easy.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(2) The electrode (20) is a short electrode whose rear end is located before and after the rear end face of the insulating spacer (10),
(30) supports the rear end of the electrode; the torch further comprises a space (31) where the rear end face (22) of the electrode is exposed;
A space (41) where the outer surface (56) of the nozzle member (50) is exposed in the inner space of (0) is provided with flow paths (81 to 87) for passing a cooling medium. Since the electrode (20) is short and its rear end face (22) is cooled by the cooling medium, the effect of removing heat from the electrode (20) is high, and the effect of suppressing a rise in temperature inside the torch is high. Therefore, it can be used at high current values. A non-transferring oscillating plasma torch that uniformly or rapidly heats or sprays a wide area of a steel material by blowing a strong plasma frame by a plasma arc having a high current value can be obtained.

(3) The rotary drive mechanism (60) comprises an external gear (63) fixed to an outer portion of the nozzle table (40) of the nozzle member (50), and a drive gear (62) meshing with the external gear. And a reduction gear (61) coupled to the drive gear (62);
Is an electric motor (70) for driving the speed reducer (61). Since the electric motor (70) rotationally drives the nozzle member (50) by gear coupling, high-speed swinging by high-speed rotation is possible, and the rotary drive mechanism (60) can be made compact and has high heat resistance. Moreover, since the entire rotary drive mechanism (60) is outside the torch, inspection and maintenance can be easily performed.

(4) Further, a powder supply means (90) for supplying powder and carrier gas is provided near the eccentric opening (52) of the nozzle member (50). According to this, the powder supplied by the powder supply means (90) is melted by the plasma frame and welded to the surface of the workpiece to be directed. Even if the workpiece is not shaken at high speed, the plasma frame itself rotates at high speed to draw a conical surface, dispersing heat and uniforming the coating.
The mechanism for scanning and driving the workpiece or the work material does not substantially require swinging, and may be any mechanism that travels to update the sprayed surface, and a simple mechanism may be employed.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0013]

【Example】

-First Embodiment- FIG. 1 shows a longitudinal section of a first embodiment of the present invention. A through hole 11 is opened at the center of the short, cylindrical or cylindrical insulating spacer 10, and a tungsten electrode 20 penetrates the center of the through hole 11. The tip of the electrode 20 is conical so that the electric arc is concentrated at its center. Electrode 20
Is the center line of the torch. An electrode holder 23 fixedly holds the circumferential surface of the rear end of the electrode 20. The electrode holder 23 is inserted into the center hole of the electrode base 30 and is fixed to the electrode base 30, and an O-ring hermetically seals between the electrode base 30 and the electrode holder 23. Electrode table 30
Is inserted into a receiving hole having a slightly larger diameter than the through hole 11 of the insulating spacer 10 and is fixed to the insulating spacer 10. An O-ring hermetically seals between the electrode base 30 and the insulating spacer 10. Is sealed.

A central sleeve of the nozzle base 40 is inserted into a through hole 11 of the insulating spacer 10 opposite to the electrode base 30 and communicating with the through hole 11 and having a slightly larger diameter than the through hole. This sleeve is hermetically sealed with an O-ring to the insulating spacer 10. Nozzle base 40 is cap nut 4
3, the cap nut 43 is screwed to the insulating spacer 10, and the nozzle base 40 is fixed to the insulating spacer 10 by screwing the cap nut 43.

The front end of the electrode 20 is located in the inner space 41 of the center hole of the nozzle table 40. A small-diameter rear end portion corresponding to a handle of a generally umbrella-shaped nozzle member 50 is inserted into the inner space 41, and is rotatably supported about the central axis 21 by the nozzle table 40 via a bearing. , And X ring 5
4 is sealed airtight. The outer edge of the large-diameter distal end portion corresponding to the umbrella of the nozzle member 50 is inserted into the distal end opening of the nozzle table 40, and is rotatably supported by the nozzle table 40 about the central axis 21 via a bearing, And it is sealed airtight by the X ring 55.

On the end face of the small diameter rear end of the nozzle member 50,
A conical hole-shaped large-diameter opening 53 centered on the central axis 21 is opened, and a conical surface at the tip end of the electrode 20 is positioned inside the opening 53 with a predetermined gap. The plasma nozzle 52 is continuous with the large-diameter opening 53, and the plasma nozzle 52 is continuous with the opening 51 on the end surface of the large-diameter tip of the nozzle member 50.

The opening 51 in the distal end face is located at a position eccentric from the center axis 21. That is, the plasma nozzle 52 bends between the opening 53 on the rear end face centered on the center axis 21 of the electrode 20 and the opening 51 on the front end face eccentric from the center axis 21. A slightly narrower circumferential portion slightly inside the outer edge of the large diameter tip of the nozzle member 50 penetrates the cap nut 44, and the cap nut 44 is screwed to the nozzle base 40. By screwing, the nozzle member 50 is positioned with respect to the nozzle table 40 in the z direction. The central part in the radial direction of the large diameter tip of the nozzle member 50 is
The flanged ring-shaped intermediate member 64 is fixed to the outside of the cap nut 44, and a ring-shaped external gear 63 is fixed to the outer periphery of the intermediate member 64. The driving gear 62 meshes with the external gear 63. The drive gear 62 is fixed to the output shaft of the speed reducer 61. The rotation shaft of the electric motor 70 is connected to the input shaft of the speed reducer 61. A handle 72 is fixed to the insulating spacer 10, and the motor mount 71 fixed to the handle 72 is fixed.
, The electric motor 70 is held.

The insulating spacer 10 has a hole 92 for introducing a plasma gas. A pipe 91 is connected to the hole 92. The hole 92 extends in the z-direction, and bends in the radial direction at a substantially central portion in the z-direction of the insulating spacer 10, and opens slightly into the space communicating with the through-hole 11 slightly behind the through-hole 11. I have. The plasma gas supplied from the pipe 91 to the hole 92 passes through the hole 92 to the space at the center of the insulating spacer 10, passes through the through hole 11 along the peripheral surface of the electrode 20, and passes through the inside of the nozzle table 40. Space 41, and electrode 2
The laser beam enters the opening 53 along the conical surface at the leading end of the nozzle 0 and passes through the plasma nozzle 52 to be ejected from the outer opening 51 to the outside of the torch.

When the power source 100 for generating a plasma arc is turned on, a plasma arc is generated between the tip of the electrode 20 and the inner surface of the plasma nozzle 52 of the nozzle member 50, and the plasma arc is generated. The plasma gas passing through is ionized, and a plasma frame is ejected from the opening 51. Opening 5
1 is eccentric from the center axis 21, so that the plasma flame
The gas is ejected at an angle to the central axis 21. When the electric motor 70 is driven to rotate, the driving gear 62 rotates, and the nozzle member 50 is driven to rotate via the external gear 63 and the splicing 64, whereby the outer opening 51 draws a circle around the central axis 21. The plasma frame ejected from the outer opening 51 draws a conical surface centered on the central axis 21.

The insulating spacer 10 has a hole 82 for introducing cooling water. A pipe 81 is connected to the hole 82. The hole 82 passes through the insulating spacer 10 in the z direction,
A hole 83 of the nozzle table 40 is connected to the hole 82. The hole 83 is open toward the column outside the column of the umbrella-shaped nozzle member 50. A water guide ring 45 is inserted into a sleeve protruding toward the tip of the nozzle base 40,
The water guide ring 45 defines a water channel along the outer periphery of the support portion of the umbrella-shaped nozzle member 50 toward the inside of the umbrella portion. This water channel communicates with the space 42 inside the umbrella.
A hole 84 opened in the space 42 penetrates the nozzle base 40 in the z direction, and a pipe 85 penetrating the insulating spacer 10 in the z direction is connected to the hole 84. One end of a U-shaped pipe 86 is connected to the pipe 85 via an insulating joint (pipe), and a pipe 87 is connected to the other end of the pipe 86 via an insulating joint (pipe). Pipe 87
Of the electrode 20 penetrates through the electrode base 30 in the z direction, and is open to a space 31 where the rear end face of the electrode 20 is exposed. This space 31
Is continuous with the inner space on the rear end side of the electrode base 30, and the distal end of the drain pipe 88 is open in the inner space on the rear end side.

The cooling water is supplied to the pipe 81-hole 82-hole 83-
It flows with the space 42 and deprives the nozzle member 50 of heat, and
The heat flows through the holes 84-pipes 85, 86, 87-space 31 to take away the heat of the electrode 20 in the space 31, passes through the inner space of the electrode stand 30, takes the heat of the electrode stand 30, and passes through the pipe 88. It flows out of the torch. The heat of the nozzle member 50 is efficiently cooled by the cooling water flowing through the inner space of the water guide ring 45 and the inside of the umbrella of the nozzle member 50. The electrode 20 is short, its rear end face and the electrode holder 3 supporting the electrode 20
0 is efficiently cooled by the cooling water flowing through the space 31. Therefore, the cooling effect of the nozzle member 50 and the electrode 20 is high, and the flow of a high plasma arc current, that is, the generation of a strong plasma frame is possible.

A plasma frame, particularly a strong plasma frame, has a high energy (mechanical force (pressure) and thermal action) on a material to be processed, and the difference in energy between the center and the periphery is large. Although it is easy to cause large processing unevenness, by rotating and driving the nozzle member 50 with the electric motor 70,
As the plasma frame rotates to draw a conical surface,
The heat distribution is uniform in the plasma frame irradiation range, and a wide range of processing can be performed in one scan.

That is, as shown in FIG. 2, when the tip opening 51 of the plasma nozzle 52 has a rotation angle that is most eccentric in the -x direction from the center axis 21, the center line (directing direction) of the plasma frame is Although it does not swing in the y direction with respect to the central axis 21, the swing in the -x direction is the maximum. When the nozzle member 50 rotates 90 degrees clockwise from this state,
As shown by the solid line in FIG. 3, the tip opening 51 of the plasma nozzle 52 is most eccentric in the + y direction from the center axis 21, and the center line of the plasma frame oscillates in the x direction with respect to the center axis 21. However, the deflection in the + y direction is maximum. When the nozzle member 50 further rotates 90 degrees clockwise from this state, the tip opening 51 of the plasma nozzle 52 is most eccentric in the + x direction from the center axis 21 as shown in FIG.
Although the center line of the plasma frame does not swing in the y direction with respect to the center axis 21, the swing in the + x direction becomes maximum.
When the nozzle member 50 further rotates 90 degrees clockwise from this state, as shown by a dotted line in FIG.
The center opening of the plasma frame is not eccentric with respect to the central axis 21 in the x direction, but is eccentric with respect to the central axis 21. Will be the largest. An example of use of the above-described first embodiment will be described below.

1. (Heating example) Number of rotations of the nozzle member 50: 15 times / second Diameter (minimum diameter portion) of the plasma nozzle 52: φ10 mm Nozzle hole deflection angle θ: 10 ° Arc current: 500 A Plasma gas: 60 l / min (Ar gas) 5 liter / min (Hz gas) (Result) The steel plate surface at about 60 mm from the tip of the torch could be heated uniformly and widely.

Second Embodiment FIG. 5 shows a second embodiment of the present invention. The structure of the plasma torch shown in FIG. 5 is the same as that of the first embodiment shown in FIG.
A powder supply device 90 is attached to the torch. In this embodiment, a powder carrier gas is supplied to a carrier gas pipe 92 having an open powder supply port at the bottom of a hopper-type powder supply device 91, and powder is drawn into the gas flow from the powder supply port. Then, it is fed into the powder injection nozzle 94 through the powder supply pipe 93 together with the gas flow, and is jetted from the nozzle 94 toward the central shaft 21. The ejected powder is sucked into the plasma frame and melted by the high heat of the plasma frame.
It collides with the surface of the material to be processed together with the frame. An example of use of the second embodiment is shown below.

[0026] 2. (Example of thermal spraying) Number of rotations of nozzle member 50: 15 times / second Diameter (minimum diameter portion) of plasma nozzle 52: φ12 mm Nozzle hole deflection angle θ: 10 ° Arc current: 800 A Plasma gas: 40 liter / min (Ar gas) 15 L / min (He gas) Powder: Alumina 30 g / min Powder carrier gas: 4 L / min (Ar gas) Distance between torch and workpiece: about 100 mm (Result) A uniform sprayed film was obtained over a wide range. Also, the work could be performed without moving the work at high speed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment of the present invention.

FIG. 2 shows the tip of the plasma torch shown in FIG. 1,
(A) is a longitudinal sectional view, (b) is a front view of the tip end surface of the nozzle member 50.

FIG. 3 shows the tip of the plasma torch shown in FIG. 1,
(A) is a longitudinal sectional view, (b) is a front view of the tip end surface of the nozzle member 50.

FIG. 4 shows the tip of the plasma torch shown in FIG. 1,
(A) is a longitudinal sectional view, (b) is a front view of the tip end surface of the nozzle member 50.

FIG. 5 is a longitudinal sectional view of a second embodiment of the present invention.

[Explanation of symbols]

10: Insulating spacer 11: Through hole 20: Electrode 21: Center axis 22: Rear end face 23: Electrode holder 30: Electrode table 31: Inner space 40: Nozzle table 41: Inner space 42: Space 43: Cap nut 44: Cap nut 45: Water guide ring 50: Nozzle member 51: Outer opening 52: Plasma nozzle 53: Rear end opening 54: X ring 55: X ring 56: Inner surface 60: Rotary drive mechanism 61: Reduction gear 62: Drive gear 63: External gear 64: Intermediate member 70: Electric motor 71 Motor mount 72: Handle 81, 85, 86, 8
7, 88: cooling water pipe 82 to 84: hole 91: plasma gas pipe 92: hole 100: power supply

Claims (4)

[Claims] An insulating spacer having a relatively large diameter through-hole at the center; an electrode penetrating through the through-hole;
An electrode base fixed to a rear end of the insulating spacer and supporting the electrode; a nozzle base having an inner space for receiving the electrode and fixed to a nozzle-side end of the insulating spacer, that is, a tip end; A plasma that enters the inner space of the nozzle base and has an opening aligned with the center axis of the electrode at the end surface, an opening eccentric from the center axis of the electrode at the outer end surface of the inner space of the nozzle base, and plasma connected to both openings A nozzle member having a nozzle and rotatably coupled to the nozzle base via a fluid seal about the central axis of the electrode; a nozzle member of the nozzle base for driving the nozzle member to rotate; A non-transitional oscillating plasma torch comprising: a rotary drive mechanism mounted on an external component; and a motor for applying a rotary torque to the rotary drive mechanism to rotate the nozzle member. 2. The electrode is a short electrode having a rear end located before and after a rear end surface of an insulating spacer, wherein the electrode base supports a rear end of the electrode; 2. The non-transferable oscillating device according to claim 1, further comprising: a space through which a rear end surface of the electrode is exposed; and a passage through which a cooling medium passes through a space inside the nozzle table, where the outer surface of the nozzle member is exposed. Dynamic plasma torch. 3. The rotary drive mechanism according to claim 1, wherein:
An external gear fixed to an outer portion of the nozzle base, a driving gear meshing with the external gear, and a speed reducer connected to the driving gear;
The prime mover is an electric motor that drives the speed reducer;
A non-transferring oscillating plasma transistor according to claim 1 or 2.
Ji. 4. The non-transition type according to claim 1, further comprising powder supply means for supplying powder and carrier gas to a portion outside the eccentric opening of the nozzle member. Swinging plasma torch.