JPH05325781A - Manufacturing device for magnetron anode - Google Patents

Abstract

PURPOSE:To efficiently weld the intersection portions of anode vanes and strap rings together with high reliability while a laser is kept oscillated by welding them with a laser beam radiated from the slant direction. CONSTITUTION:Multiple anode vanes 35 are positioned and held by a holding jig 33. A mask ring 37 has the preset thickness, it is arranged in contact with or near the anode vanes 35 and strap rings 51, 52, and through holes 36a, 36b are formed at positions corresponding to intersection portions of the anode vanes 35 and the strap rings 51, 52. The center axis Z of the anode vanes 35, strap rings 51, 52, and mask ring 37 is held at the slant preset angle against the radiation direction of a laser beam 41, and a rotating device 29 rotating them around the center axis Z is provided. The intersection portions of the anode vanes 35 and the strap rings 51, 52 to be connected can be continuously welded together by the laser beam 41 radiated from the slant direction through the through holes of the mask ring 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a magnetron anode, and more particularly to an apparatus for laser welding an anode vane and a strap ring.

[0002]

2. Description of the Related Art As is well known, a magnetron used in, for example, a microwave oven has, for example, an internal cylinder of an anode made of copper.
An anode assembly is provided in which zero copper anode vanes are joined together, and a pair of small diameter inner strap rings and large diameter outer strap rings are electrically shorted to every other anode vane. Until now, the anode vane and each strap ring were connected by brazing, but large-scale brazing equipment is required, and expensive brazing material such as silver brazing is required, which is equivalent to brazing. There is an inconvenience that requires a long time. Therefore, a technique for joining these by laser welding is being developed.

[0003]

The anode cylinder, anode vane, and strap ring of the magnetron are made of copper or copper alloy. For laser welding of these copper materials,
A carbon dioxide laser with a relatively long wavelength is suitable. However, this carbon dioxide gas laser is more difficult to instantaneously turn on and off than a YAG laser or the like. Therefore, it is necessary to weld each joining position of the 10 anode vanes and the pair of strap rings without excess or deficiency while continuing the laser oscillation. Further, when a copper material is irradiated with a laser beam, the laser light reflectance of the copper surface is high, and 90% or more of the irradiation energy is reflected. Therefore, it is necessary to irradiate the outer peripheral surface with a laser beam in an oblique direction so that the reflected laser light does not return to the laser oscillator.

The present invention has been made in view of the above circumstances, and provides a manufacturing apparatus of a magnetron anode capable of efficiently welding each intersection of the anode vane and the strap ring while continuously irradiating the laser beam. The purpose is to do.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a holding jig for positioning and holding a plurality of anode vanes, and an intersection of the anode vanes and the strap rings which are arranged in contact with or in the vicinity of the anode vanes and the strap rings. A mask ring of a predetermined thickness with a through hole formed at a position corresponding to the portion, and the central axes of these anode vanes, strap rings, and mask rings are held at a predetermined angle oblique to the laser beam irradiation direction and An apparatus for manufacturing a magnetron anode, comprising: a rotating device that rotates about a central axis.

[0006]

According to the present invention, each intersection of the anode vane and the strap ring to be joined is welded substantially continuously by the laser beam obliquely irradiated through each through hole of the circle arrangement of the mask ring. be able to.
Therefore, the anode vane and the strap ring can be welded efficiently and with high reliability while oscillating and irradiating the laser.

[0007]

Embodiments will be described below with reference to the drawings.
The same parts are denoted by the same reference numerals. FIG. 1 shows the entire structure. The device base 21 has an upper surface 22 with an angle θ of about 20 degrees. A stepping motor 24 is fixed to this via an L-shaped bracket 23. A slide base 27 that can reciprocate along a guide rail 26 as shown by an arrow Fa is screwed onto a ball screw 25 of the motor 24. The slide base 27 has a crank bracket
Servo motor 29 is fixed via 28. A chuck 31 is attached to a shaft 30 of the motor 29, and a holding jig 33 is detachably held by a claw 32 of the chuck.

The holding jig 33 has ten copper anode vanes 35 radially fixed to the inside of the copper anode cylinder 34, and a pair of small diameter inner strap rings 51 and 51 inside the strap ring mounting groove 35a. A large diameter outer strap ring 52 is positioned and retained. A mask ring 37 having a relatively large wall thickness is coaxially fitted over the anode vane and the strap ring and is detachably held. The mask ring 37 has through holes 36a and 36b formed in a circle. The holding jig 33 has a center support rod 3
8. Vane tip holding jig 39 and tightening bolt 40 are fitted. Then, the laser beam 41
Is being irradiated. The laser beam 41 is a circular beam having a diameter of about 60 mm, which is generated from a carbon dioxide gas laser oscillator (not shown).
Irradiation is performed by 42 with a focusing angle α of about 20 degrees so that the focal point is located at the intersection of the anode vane and the strap ring. Holding jig 33, anode vane 35, each strap ring 5
1,52, the mask ring 37, etc. are assembled in advance by only these before being attached to the chuck of this apparatus.

The mask ring 37 is preferably in a surface state such that the outer surface has a laser light reflectance of 90% or more such as copper, and the thickness of the portion where the through hole is formed is 3 mm or more. Have And this mask ring 37
As shown in FIGS. 2 and 3, five through holes 36a for welding the inner strap ring and five through holes 36b for the outer strap ring are alternately formed in a circle. There is. The through hole 36a for welding the inner strap ring is
A portion near the central axis z corresponding to the welding position between the anode vane and the inner strap ring is a through hole 36c, and an outer portion thereof is a step portion 36d in the middle in the thickness direction. The step portion 36d is located at a position where the laser beam when welding the outer strap ring is reflected by the step surface. Similarly, a portion relatively distant from the central axis z corresponding to the welding position of the anode vane and the outer strap ring becomes the through hole 36e,
The inner part is a step 36f. This step 36f
Is at the position where the laser light when welding the inner strap ring is reflected by this step surface. Also, the mask ring 37
Each of them is provided with a positioning projection 37a for accurately positioning the through hole and the position to be welded, a projection 37b for pressing each strap ring, and a recess 37c for receiving the bolt 40. The positioning protrusion 37a defines the relative position between the welded portion and each through hole with one anode vane sandwiched therebetween. The upper wall 37d forming the recess 37c reflects the irradiation laser light while the central axis of the holding jig 33, which will be described later, is translated. If the bolt 40 is made of a highly reflective material such as copper, the upper wall 37d can be eliminated and the recess can be used as a through hole.

The parts are assembled as shown in detail in FIGS. 4 and 5. That is, the anode cylinder 34 and the anode vane 35 are mounted on the holding jig 33. As shown in FIG. 6, the holding jig 33 has a central through hole 33a through which a center support rod is inserted, and a protrusion 33c having ten slits 33b for positioning the anode vane, and a supporting anode cylinder. It has a stepped portion 33d. Around the center support rod 38 inserted through the holding jig 33, a pair of comb tooth-shaped rings 43, 43 and a pair of taper rings 44, 44 are fitted face to face between them. A pair of comb tooth-shaped rings 43 receive and position the inner ends of each vane, as shown in FIG.
It has individual recesses 43a. A pair of taper rings 44,44
A vane pressing C-ring 45 is held between them. A tightening bolt 40 is screwed into a female screw 46 at the tip of the center support rod 38 via a washer. As shown in FIGS. 8A and 8B, the vane pressing C-ring 45 is made of an elastic material having a high hardness, such as a piano wire,
The outer surface 45a, which has a trapezoidal cross section and is straight, is the anode vane.
It touches the inner end face of 35, and in a natural state, the joint 45b is in close contact. As shown in FIG. 8 (c), the C-ring 45 for pressing the vane is spread by the taper surface of the taper rings 44, 44 with the tightening bolts 40 tightened and the gaps narrowed. Press 35 outwards. Then, the pair of strap rings 51, 52 are fitted in the strap ring mounting groove 35a formed at the end portion of the anode vane, and the mask ring 37 is pressed onto the pair. The toothed ring, taper ring, and vane pressing C-ring of these combs are used to position and support the inner tip of each anode vane.
The vane tip positioning device 39 shown in FIG.

After assembling in this way, laser welding of the anode vane and the strap ring is performed. First, the laser beam
The focal point of 41 is the outer strap ring 52 and the anode vane 35.
The central axis z is translated and positioned by the stepping motor 24 so as to be concentrically aligned with the welding points at the intersections with and. The beam is generated by continuously oscillating the laser 41
Is first positioned in the middle of the adjacent through holes 36a, 36b on the upper wall surface of the mask ring 37. Then, the servo motor 29 is driven to rotate once at a predetermined speed. Thereby, the laser beam 41
Is irradiated in an oblique direction from the central axis z side to the outside as shown in FIG. 4 and FIG. 5, passes through each through hole 36b, and intersects with the alternate anode vane 35 and the outer strap ring 52. Focus on and weld all concentric intersections one after another. The relationship between the through holes of the mask ring 37 and the welded portions of the anode vanes 35 and the inner and outer strap rings 51 and 52 is as shown in FIG. And
A laser welding portion between the anode vane 35 and the outer strap ring 52 is represented by reference numeral B1 in FIGS. 9 and 10. The welded portion B1 is connected to the outer strap ring 52
It is located at the contact portion between each outer small protrusion 52a provided on the ridge and the side surface of the step portion of the anode vane 35.

After the servomotor 29 is rotated once and stopped, the stepping motor 24 is driven so that the position of the laser beam 41 is concentrically aligned with the welded portion at the intersection of the inner strap ring 51 and the anode vane 35. Translate to the position you want. Then, the servo motor 29 is rotated once at a predetermined speed. As a result, the laser beam 41 is emitted from FIGS.
As indicated by the dotted line in FIG. 1, the intersection point of the anode vane 35 and the inner strap ring 51 which are radiated obliquely from the outside toward the center axis z and pass through each through hole 36a. Focus on the part to be welded and weld this part one after another. These welds are designated as B2 in FIGS. 9 and 10.
It is represented. The welded portion B2 is located at the contact portion between each inner small protrusion 51a provided on the inner strap ring 51 and the step side surface of the anode vane 35. Thus, all intersections are welded.

The laser beam 41 is applied to the mask ring 37.
After passing through each of the through holes, the contact position between the anode vane and the strap ring is obliquely irradiated at an angle of about 70 degrees with respect to these horizontal planes. Due to this angle, the surface reflected light of the laser does not return to the oscillator direction and does not cause oscillator instability. Further, the irradiation laser beam at the time of welding the outer strap ring enters the through hole for welding the inner strap ring, but does not undesirably locally melt the anode vane and the strap ring. That is, as shown in FIG. 11A, the laser light for welding the outer strap ring passes through the penetrating portions 36e of the corresponding through holes 36b and is accurately focused on the welded portion. When the laser light 41 is rotated once during this laser irradiation,
As shown in 1 (b), it also enters each through hole 36a for welding the inner strap ring, but it is reflected by the surface of the step 36d in the middle as shown by the dotted line and goes out through the large opening. go. On the other hand, the irradiation laser light at the time of welding the inner strap ring also enters each through hole for welding the outer strap ring, but similarly, the anode vane or the like does not undesirably locally melt. That is, the laser light during welding of the inner strap ring passes through the through portions 36c of the corresponding through holes 36a and is accurately focused on the welded portion, as shown in FIG. 12 (a). During this one rotation, the laser beam 41 also enters the through holes 36b for welding the outer strap ring as shown in FIG. 12B, but as shown by the dotted line on the surface of the step 36f in the middle. It is reflected by and goes out through the large opening. In this way, laser welding of both strap rings can be performed without inconvenience.

Even if the upper wall surface or step surface of the mask ring 37 is irradiated with the laser beam, the irradiation surface is displaced from the focus of the laser beam, and the surface of the mask ring is Since most of the energy is reflected, there is no risk of the mask ring itself melting. Further, since the predetermined gap G is provided between the mask ring and the welded portion, there is no possibility that the both are joined.

In this way, all the welding points can be welded substantially continuously. After this welding is completed, the laser irradiation is stopped, the holding jig 33 is removed from the claw 32 of the chuck 31, the mask ring is removed, and the bolt 40
Loosen and flip the anode cylinder and anode vane over and reinstall, and weld a pair of opposite strap rings as above. Then, the holding jig in which the next parts to be welded are assembled is attached to the chuck 31, and the next anode structure is welded.
These are the optical shutters (not shown) of the laser generator.
Alternatively, a predetermined sequence control program may be stored in a rotating device such as a servo motor, a parallel moving device such as a stepping motor, and a microcomputer that controls them, and may be configured to perform automatic control as appropriate. For the mask ring, prepare one having only the through hole 36a for welding the inner strap ring or the through hole 36b for welding the outer strap ring, and attach them alternately to attach both strap rings. It may be configured to be laser welded.

By the way, since the laser beam has an aperture angle of about 20 degrees as described above, the through hole of the mask ring has an opening width s of the laser beam incident side of the anode vane 35 as shown in FIG. It is necessary to form it larger than the plate thickness t. Then, the both centers s ₀ and t ₀ are attached so that they coincide with each other, and the laser beam is applied to the anode vane 35 and the strap ring 51.
While irradiating the intersection point with, each part is rotated as shown by arrow Fb and welded. When welding is performed with such settings, there are many cases in which a good welding state can be obtained by optimizing the laser beam output and the like. However, as shown by reference numeral B ₃ in the figure, the portion irradiated last with the laser beam may be excessively melted as compared with the portion irradiated with the laser beam first, and “melt dripping” may occur. .. this is,
It is considered that this is because the heat capacity of the tip portion of the anode vane and the strap ring is small, and the material is excessively melted in the latter half of the beam irradiation. This tendency is especially strong at the welded portion between the small-diameter inner strap ring and the vane. Therefore, a part of the tip of the vane facing the electron emitting cathode may be melted and lost, or the initial shape of the tip surface may be distorted. If this happens, normal operation of the magnetron cannot be obtained.

An embodiment for eliminating such inconvenience is shown in FIG. This is a configuration in which the center s ₀ of each through hole 36a (36b) of the mask ring 37 is slightly displaced from the plate thickness center t ₀ of the anode vane 35 in the rotational direction Fb of each component. Each through hole is formed with the same circumferential width dimension in the thickness direction of the mask ring 37, and one side corresponding to the latter half of the passage of the laser beam is substantially aligned with one end of the anode vane 35. is there.

According to this embodiment, as shown in FIG. 15A, the welded portion B2 between the anode vane 35 and the strap ring 51 is in a substantially even welded state. The reason is that when each part is rotated at a constant speed as shown by the arrow Fb, the through hole
As shown in (b) and (c) of the same figure, the laser beam which passes through 36a is irradiated with the laser beam as shown by reference numeral 41a at the start of laser beam irradiation at the welded portion at this intersection. All is irradiated to the tip of the welded part. That is, irradiation is performed with a laser energy intensity of 100%. Then, the laser beam is irradiated with 100% as it is until the time point 41b at which the laser beam starts to be blocked by the mask ring 37, and welding is performed. However, from this point, the laser light is masked
The laser irradiation intensity gradually decreases as it is blocked by 37 and the focus reaches the welding end position of the welded part.
41c and the laser irradiation intensity is about 50%. In this way, the laser intensity is reduced from the middle of welding, so that the possibility of excessive melting near the end of welding is eliminated, and a uniform welded state is obtained along the rotation direction.

In the above embodiment, both the welding of the small-diameter inner strap ring and the welding of the large-diameter outer strap ring are arranged with the plate thickness center of the anode vane and the through hole center of the mask ring displaced. However, not limited to this, the outer through holes 36b for welding the large-diameter outer strap ring having a relatively large heat capacity may be configured such that their centers are aligned. Further, by appropriately setting the shape of the inner wall surface of the through hole, the intensity of the laser beam with which the welded portion is irradiated can be appropriately distributed.

The embodiment shown in FIGS. 16 and 17 is an apparatus for laser-welding the anode vane and the strap ring by accurately positioning them without fixing the anode vane to the anode cylinder. That is, a positioning cylinder 53 having an inner diameter corresponding to the inner diameter of an anode cylinder (not shown) is fixed to the outer periphery of the holding jig 33 with bolts 54. 1 for the positioning slit formed on the protrusion 33c of the holding jig 33.
Put on zero anode vanes 35. Then, at the inner end of the vane, a pair of comb tooth-shaped rings 43, 43, taper rings 44, 44,
Then, the vane pressing C ring 45 is fitted to the center support rod 38, and the tightening bolt 40 is tightened through the washer.
The vane pressing C-ring 45 is expanded by the tapered surfaces of the taper rings 44, 44 to radially expand the 10 anode vanes 35 and press the outer end surface of each vane against the inner peripheral wall surface of the positioning cylinder 53. Then, the pair of strap rings 51, 52 are fitted in the strap ring mounting groove 35a of the anode vane, and the mask ring 37 is mounted thereon. Using this device, the laser beam 41 is obliquely irradiated through the through holes 36a and 36b of the mask ring as described above, and the intersections between the strap rings and the anode vanes are welded.

[0021]

As described above, according to the present invention,
The intersections of the anode vane and the strap ring to be joined can be welded substantially continuously by the laser beam irradiated obliquely through the through holes of the circle arrangement of the mask ring. Therefore, the anode vane and the strap ring can be welded with high efficiency and good quality while oscillating the laser.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing an enlarged main part of FIG.

FIG. 3 is a top view of that of FIG.

FIG. 4 is a longitudinal cross-sectional view of a main part showing a welded state of FIG.

FIG. 5 is an enlarged view of FIG.

FIG. 6 is a top view showing a part of the component.

FIG. 7 is a top view showing a part of the component.

FIG. 8 is a cross-sectional view and a side view showing a part and a mutual relationship of parts.

1. FIG. 9 is a top view of the essential parts showing the welded state of FIG.

FIG. 10 is a top view showing a product after welding is completed.

FIG. 11 is a half cross-sectional view of essential parts showing a welded state.

FIG. 12 is a semi-sectional view of a main portion showing a welded state.

FIG. 13 is a schematic diagram illustrating a welding state.

FIG. 14 is a top view of essential parts showing another embodiment of the present invention.

FIG. 15 is a schematic diagram illustrating a welding state according to FIG.

FIG. 16 is a longitudinal sectional view of a main part showing still another embodiment of the present invention.

FIG. 17 is an enlarged view of a main part of FIG.

[Explanation of symbols]

35 ... Anode vane, 51, 52 ... Strap ring, 41 ... Laser beam, B1, B2 ... Laser weld, 33 ... Holding jig, 36
a, 36b ... Through hole, 37 ... Mask ring, 24, 25, 27 ... Translation device, 29, 31 ... Rotation device.

Claims (3)

[Claims] 1. A small-diameter inner strap ring and a large-diameter outer strap ring are brought into contact with every other one of a plurality of radial array anode vanes, and a laser beam is irradiated to the intersection of the anode vanes and the strap rings. In a manufacturing apparatus for a magnetron anode that is welded by welding, a holding jig for positioning and holding the anode vane and a contact jig arranged in contact with or close to the anode vane and the strap ring and corresponding to an intersection of the anode vane and the strap ring. A mask ring of a specified thickness with a through hole formed in its position, and the central axes of these anode vanes, strap rings, and mask rings are held at a specified oblique angle with respect to the laser beam irradiation direction, and these are placed around the central axis. Of a magnetron anode, comprising: Location. 2. The mask ring is formed such that the center position of the laser beam incident side opening of each through hole of the mask ring is shifted toward the plate thickness center position of the anode vane in the rotation advancing direction by the rotating device. The magnetron anode manufacturing apparatus described. 3. A laser beam irradiation position is moved parallel to a central axis of the anode vane, the strap ring and the mask ring so that the laser beam irradiation position is an intersection point between the anode vane and the inner strap ring, and the anode vane. 3. The magnetron anode manufacturing apparatus according to claim 1, further comprising a parallel moving device that moves between an intersection of the outer strap ring and the outer strap ring.