JPS5826774B2 - electron gun - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun that generates an electron beam used for welding members.

The advantages of electron beam welding for butt welding thick plate parts, such as those used in pressure vessels, are well known, as this welding process requires much fewer layers than other welding methods. This is because joining can be performed by numbers.

It was thus discovered that by using a concentrated electron beam of 100 KW, it was possible to butt weld members with a thickness of 200 rran in one layer.

Such electron guns are designed to operate at high voltages, typically 150 KV, and insulation of the electrode areas of these guns is typically done by conventional techniques under complete vacuum. .

However, in order to achieve the above-mentioned deep penetration, the mechanical precision of the internal structure of the electron gun, especially the precision of the coaxial arrangement of the filament, cathode, Wehnelt, and anode, is extremely important.

In particular, since the cathode is at a high temperature, in such a large-capacity electron gun, it is difficult to eliminate heat from the cathode support material or adjacent members and maintain the coaxial alignment accuracy.

For this purpose, a cooling circuit using oil circulation is installed, and various other methods are used. Although these methods are acceptable for stationary equipment and laboratory applications, they are not suitable for heavy equipment manufacturing plants or on-site applications. The problem is that the structure is too large to compete with the movable high-power electron gun needed to apply the electron beam in the field.

The present invention is particularly aimed at improving these disadvantages.

For this reason, the electron gun of the present invention incorporates within the main body a means for electrically insulating the cathode, filament, Wehnelt, and anode from each other and mechanically supporting them in a coaxial arrangement.

A typical feature of this electron gun is that a plurality of rods of conductive material mechanically support a cathode located on a central axis.

One end of these rods is rigidly fixed to the frame, and the other end is pressed firmly against the circumferential side wall of the cathode to serve as a positioning clamp for the cathode.

Therefore, even if the temperature of the rod holding the cathode, the cathode support supporting the rod, or the adjacent members rises or thermally expands, the rod will remain on the circumferential side wall of the cathode in its tangential direction. Because the cathode expands and contracts, simply rotating the cathode slightly around its central axis does not impair the accuracy of its relative coaxial placement with the filament, Wehnelt anode, etc.

Another feature of the invention is that the rod supporting the cathode is
It is fixed to the insulator end plate via the cathode support.
The insulating end plate holds the cathode, the filament and Wehnelt, and a fastening means which is insulated from each other and is firmly fixed to the frame.

Still another feature of the invention is that the means for fixing the filament, Wehnelt and anode to the insulator end plate includes at least some of the means for securing the filament, Wehnelt and the anode to the insulator end plate, such that at least some of the means pass through the end plate and end opposite the filament, Wehnelt and the cathode. It is connected to the output supply cable on the board surface.

Still another feature of the present invention is that at least some of the means for fixing the cathode, filament, and Wehnelt to the insulator end plate protrude into the hollow part of the insulator made in a hollow shape, and the tips thereof are cooled. It has fins.

Means for circulating air through these fins is also provided.

The invention particularly reduces the volume and weight of the electron gun, cools it in such a way that it does not limit the use of the electron gun to stationary welding equipment, and also incurs a loss of only 750W to operate a 100KW electron gun, for example. The aim is to produce an electron gun cathode assembly that ensures high thermal efficiency.

Embodiments of the present invention will be described in detail below with reference to the drawings.

First, in FIG. 1, a support body 1 made of mild steel is a focus
A cylindrical body 3 made of stainless steel is used for the framework of the coil 2.
The inside is kept airtight to create a passage 4 for the electron beam.

A cylindrical body 5 is hermetically fixed to the support 1, which houses an optical aiming device 6 and a valve 7 which closes off the acceleration chamber 8 of the electron beam when the working area is exposed to the atmosphere.

The optical aiming device 6 comprises a prism 10 which is retractable with an air cylinder 11 and a sighting telescope (not shown).

The closing valve 7 is actuated by a pneumatic cylinder 12.

Air cylinders 11 and 12 act on prism 10 and valve 7, respectively, with a Rondo mechanism 13 to move prism 10 and sealing valve 7 out of the path of the electron beam during operation of the electron gun.

On the right side of the cylinder 5 there is an opening 14 and a machined surface 15 in which the subassembly consisting of the valve 7, the prism 10 and their control elements can be arranged in a gas-tight manner and also in a removable manner. installed on.

The pedestal 16 is provided to eliminate overburden so that the entire assembly has good mechanical operation.

A support plate 17 and a main body outer cylinder 18 are hermetically fixed to the cylindrical body 5 with bolts 19.

Support plate 17 supports anode 20 .

The anode itself is held by a presser foot 21 and a spacer 22.

The left side surface of the main body outer cylinder 18 has an opening 23 connected to a vacuum device via a flange 24.

Further, a hollow tapered first insulator 25 made of a synthetic resin mold is attached to the main body outer cylinder 18 by an airtight fixing means.

The insulator 25 includes an end plate 26 of a fire-resistant (refractory) oxide.
is held airtight by a seal 27.

The end plate 26 has a cathode emitter 40, a cathode support 28 fixed by three hermetic penetrations 29, a Wehnelt support ring 30 fixed by three other hermetic penetration bolts 31, and a primary filament support. 34 is fixed.

The Wehnelt 32 itself is held by a ring nut 33 and has a shape adapted to the beam being generated.

The primary filament 35 is connected at one terminal to the filament support 34 and at the other terminal to the central body 36,
The support body 34 is hermetically fastened onto the end plate 26 with a ring nut 37 and a washer 38 via a packing 39.

The high voltage is transmitted through four conductors 41 to the electrode area of the electron gun.
1 is supplied through a cable 41 containing a built-in cable.

That is, the heating of the primary filament is carried out by two conductors, the remaining conductors being the main connection with one of the three through-bolts 29 supporting the cathode and the Wehnelt and the three through-bolts 31 supporting it. This is a connection with one.

The four conductors 411 and the terminals 42 with corresponding terminals 29, 31, 34° 36 are elastically connected with the help of a spring 42□ fixed to a pin support 43 made of synthetic resin mold.

This pin support 43 is fixed to a second insulator 44 of silicon, which constitutes an insulating socket for the high voltage supply cable.

The second insulator 44 and the cable 41 are covered with a metal hood 45.
and are firmly connected to each other by a packing presser 45□, and the high voltage feed cable 41 is attached to the main body outer cylinder 18.

The second insulator holding the cable 41 has one side connected to the duct 4
7 and 48 to the flange 49, the other to the pin support 43
A cavity 46 is formed which is connected to a recessed area 51 surrounding the cooling fins via a vent hole 50 made in the cooling fin.

The assembly of the hood 45 includes the second insulator 44 and the first insulator 25.
Between 0 and 0, the outside air is communicated through a vent 53, and a vent 54 is connected to the outside air.
narrow pleat-like gaps 52 leading into recessed areas 51 by
is formed.

Dry air source 491 directs airflow through flange 49.

This air sequentially flows through the ducts 48, 47 and the void 50,
Cooling fin 311, 29□341, through bolt 31.2
9. Cool the filament support 34 to form the recessed area 51
is swept out, and then spreads through the vents 54, the pleated gaps 52, and the vents 53 into the atmosphere.

Between the vent 50 and the recessed area 51 the dry air is directed with a deflection plate 55.

FIGS. 3 and 4 show, in connection with the cathode support 28,
Although the attachment force of the cathode 40 itself is shown, this attachment is designed to hold three tungsten rods 56 to the cathode support 28 via a block 58 made of refractory oxide. metal clamp 57
It consists of.

The whole can be rotated symmetrically with respect to the optical axis 59 of the electron gun.

As can be seen from FIG. 2, the cathode 40 has an annular groove 40.
□, in whose grooves three tungsten rods 56 are placed 1200 degrees apart from each other to restrain the cathode 40 and to ensure that the cathode contacts the tungsten rods only at well-defined contact points. It is installed in the tangential direction.

As described above, the present invention electrically insulates the filament, cathode, Wehnelt, and anode of an electron gun and holds them in a coaxial arrangement. By gripping and positioning the circumferential side wall, the relative coaxial positioning accuracy of the cathode can be maintained even if the high heat of the cathode increases the temperature of the cathode support and adjacent components, causing thermal expansion of these components. This made it possible to create a high-precision, high-power electron gun that enables deep penetration without damaging the material.

The present invention can be implemented in the following manner.

1. The electron gun according to the claims, wherein the filament, Wehnelt, and cathode supports are insulated from each other, pass through an insulating end plate, and are hermetically sealed and tightened.

2. The electron gun according to the claims, wherein the rod means for gripping the cathode is made of tungsten.

3. The electron gun according to the claims, wherein the insulating end plate 26 is made of a fire-resistant (hardly meltable) material.

4. An electron gun according to the claims, characterized in that the cathode has a groove around its periphery, into which the end portion of the rod means is fitted.

5. The electron gun according to claim 6, wherein the rod means for gripping the cup P is comprised of three rods arranged at 120 degrees from each other.

6. The electron gun according to claim 6, wherein the rod means for gripping the cathode is arranged so as to contact the side wall of the cathode in the tangential direction.

7 A cylindrical frame of the electron gun supports a hollow tapered first insulator having an outwardly facing flange at the large diameter end and an inwardly facing flange at the small diameter end, and a sealing means is fitted around the periphery. and an insulating end plate attached to the inwardly directed flange, the insulating end plate having a fastener for holding the Wehnelt, filament and cathode in a fixed relative relationship to each other insulated from the hollow portion. The fastener is
passing through the entire thickness of said insulating end plate for connection to a power supply terminal pin held in a second insulator held concentrically in said first insulator hollow; An electron gun according to the claims.

8 The second fastener that penetrates the insulator end plate
2. An electron gun according to claim 1, wherein cooling is performed by air circulating in a hollow space inside the insulator, and fins are provided to remove heat from the fastener.

9. The second insulator comprises a pin support including a spring-loaded pin connected to the power supply conductor for resilient electrical connection with the cathode, Wehnelt and filament fasteners. An electron gun according to the claims.

10 the second insulator constitutes a plug and retains the pin support within the hollow of the first insulator, but in spatial relationship between the two insulators to cool the cooling fins; An electron gun according to claim 1, further comprising a pleated gap for passing air therethrough.

All the features of this electron gun according to the invention reduce the size of the electron gun and, as a result, reduce the temperature increase of parts attached to or adjacent to the cathode, with a view to realizing a movable welding device. It is useful for reducing

Moreover, these features ensure precise positioning of the cathode that is not affected by heating.

Of course, the invention is not limited to the practical example described above; other methods and other arrangements can be envisaged without departing from the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the electron gun of the present invention, FIG. 2 is a joint cross-sectional view of the electrode area, and FIG. 3 is a plan view showing the cathode attachment, looking upward from the bottom surface. be. Figure 4 shows an example of clamping a tungsten rod.
FIG. 3 is a sectional view taken along line A-A. Explanation of symbols, 1: Support body, 2: Focus ° coil, 3
, 5: Cylindrical body, 4: Electron beam passage, 6: Optical aiming device, 7: Blocking valve, 8: Electron beam acceleration chamber, 9: (missing number), 10 Nibrism, 11° 12: Air cylinder, 13
: rod mechanism, 14: opening, 15: machined finished surface,
16: cradle, 17: support plate, 18 two-body outer cabinet, 19: bolt, 20 near node, 21: presser foot, 22 varnish spacer, 23: opening, 24: flange, 25: first insulator,
26: Insulating end plate, 27: Seal, 28: Cathode support, 29, 31: Airtight penetration bolt, 2929□, 31□
: cooling fin, 30: Wehnelt support L32: Wehnelt, 33: ring oak), 34: filament support, 34. : Cooling fins, 35 primary filaments, 3
6: Central body, 37: Ring nut, 38: Washer, 39
: Nokutsukin, 40: Cathode emitter, 401:
Annular groove, 41: Cable, 41□: Conductor, 42: Terminal, 43: Pin support, 44: Second insulator, 45: Hood, 45□: Packing holder, 46: Blank space, 47° 48:
Duct, 49: Flange, 491: Dry air source, 50
, 53. 54: Vent, 51: Recessed area, 52: Pucker-like gap, 55: Deflection plate, 56: Tungsten rod, 57:
Clamp, 58 Niblock.

Claims (1)

[Claims] 1 A welding electron gun that generates an electron beam with high power density, comprising means for electrically insulating a filament, a cathode, Wehnelt, and an anode from each other and holding them in a coaxial arrangement, the holding means for the cathode being An electronic device characterized in that it includes a plurality of thermally conductive and electrically conductive rod means having one end fixed to a cathode support for holding the coaxial arrangement and the other end gripping and positioning the circumferential side wall of the cathode. gun.