JP2009058284A - Energy beam irradiator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an energy beam irradiator capable of deoxygenating an irradiation zone of an irradiation object by inhibiting gas from flowing into an electron beam generating section, reducing the capacity of a differential exhausting pump and avoiding scattering of an electron beam. <P>SOLUTION: The energy beam irradiator includes a generation section 11 for generating an energy beam, a through hole 21 extended from the generation section 11 toward an irradiation object and allowing the energy beam to pass through onto the irradiation object, a differential exhausting section having a pressure gradient formed inside the through hole 21 and decreasing in pressure from the irradiation object side toward the generation section 11, and a jetting section 24 for forming a circular tubular inert gas jet covering the circumference of the energy beam from the vicinity of the irradiation object side of the through hole 21 and jetted toward the irradiation object. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an energy beam irradiating apparatus, and more particularly to an energy beam irradiating apparatus that irradiates a metal large structure with energy rays and performs a process such as quenching on the surface of the structure.

  In an apparatus that irradiates an energy beam such as an electron beam, a configuration is known in which a through-hole that communicates from an electron beam generator maintained in a high vacuum to the outside is provided, and the irradiated object is irradiated with the electron beam through the through-hole. ing. In such a configuration, a differential evacuation pump is provided in the through hole, and the electron beam generating portion is maintained at a high vacuum.

  In the above-described apparatus, a method for reducing the apparatus cost and the running cost by reducing the differential exhaust pump capacity is known. For example, a technique is known in which a gas flow is formed in a direction substantially perpendicular to the electron beam emission direction, and the gas flow from the outside to the electron beam generation unit is inhibited by a differential pressure generated by the gas flow.

On the other hand, the electron beam generator and the object to be irradiated are partitioned by an irradiation window, the electron beam generator is kept at a high vacuum, and an inert gas is sprayed onto the irradiation region irradiated with the electron beam in the object to be irradiated, A technique is also known in which an irradiation region is placed in a deoxygenated environment to prevent oxidation of the irradiation region (see, for example, Patent Document 1).
JP 2002-341097 A

  However, as described above, the method of forming a gas flow in a direction substantially perpendicular to the electron beam emission direction cannot sufficiently inhibit the gas flow flowing from the outside into the electron beam generation unit. There was a problem that the pump capacity could not be reduced sufficiently.

  Furthermore, in the method of spraying an inert gas on the irradiation region of the irradiated object described in Patent Document 1, the electron beam is scattered in the irradiation window even if the inflow of gas to the electron beam generation unit can be prevented. There was a problem.

  The present invention was made in order to solve the above-mentioned problem, and while preventing gas inflow to the electron beam generation unit, while reducing the capacity of the differential exhaust pump and preventing scattering of the electron beam, An object of the present invention is to provide an energy beam irradiation apparatus capable of deoxygenating an irradiation region in an irradiation object.

In order to achieve the above object, the present invention provides the following means.
An energy beam irradiation apparatus according to the present invention includes a generation unit that generates an energy beam, a through hole that extends from the generation unit toward the irradiated body, and through which the energy beam passes toward the irradiated body. A differential exhaust part that forms a pressure gradient in which the pressure decreases from the irradiated object side toward the generating part, and from the vicinity of the irradiated object side end part of the through-hole, covering the periphery of the energy line, And a jetting portion for forming a cylindrical inert gas jet jetted toward the irradiated body.

  According to the present invention, by forming an inert gas jet in a cylindrical shape toward the irradiated body in the vicinity of the end of the through hole in the irradiated body side, the pressure in the vicinity of the opening on the irradiated body side in the through hole is The load applied to the differential exhaust unit is reduced. That is, by forming a cylindrical inert gas jet, the static pressure in the region connected to the inside of the jet, that is, the opening of the through hole, is reduced by the dynamic pressure of the jet. As a result, the differential pressure between the end portion on the generation portion side and the end portion on the irradiated body side in the through hole is reduced, and the load on the differential exhaust portion is reduced.

  The opening on the irradiated body side in the through hole is covered with a cylindrical inert gas jet, and is partitioned into an inner side and an outer side by the inert gas jet, so that gas can be prevented from entering the generating part. For example, compared to a case where an irradiation window or the like for preventing gas from entering the generating portion is provided at the end of the through hole, there is nothing to block the energy rays, so that scattering of the energy rays is prevented.

Further, the cylindrical inert gas jet becomes a gas curtain and flows toward the irradiated object while covering the periphery of the energy beam. Therefore, the inside of the inert gas jet, that is, the periphery of the energy line can be an inert gas environment.
At this time, when the distance between the irradiated body and the ejection portion is so close that the cylindrical inert gas jet does not diffuse, an inert gas environment is formed around the irradiation region irradiated with the energy rays in the irradiated body. Produced. Therefore, deoxygenation of the irradiation region in the irradiated object can be achieved.

  In the said invention, it is desirable that the inert gas from the said ejection part is gas which consists of a light element.

According to the present invention, collision scattering between an energy beam and an inert gas can be suppressed by making the inert gas a gas composed of a light element.
As the light element here, helium (He) or the like can be exemplified.

  According to the energy beam irradiation apparatus of the present invention, an inert gas jet is formed in a cylindrical shape toward the irradiated body in the vicinity of the end of the through hole on the irradiated body side, so that gas flows into the electron beam generating section. In addition, it is possible to reduce the capacity of the vacuum pump for differential evacuation and prevent scattering of the electron beam, thereby deoxygenating the irradiation region in the irradiated object.

An electron beam irradiation apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic diagram illustrating a schematic configuration of an electron beam irradiation apparatus according to the present embodiment.
In the present embodiment, the present invention is an apparatus that emits an electron beam out of particle beams included in an energy beam, and the surface of a mold (irradiated body) M is irradiated with an electron beam and quenched. Description will be made by applying to an electron beam irradiation apparatus (energy beam irradiation apparatus) 1 that performs processing.

  As shown in FIG. 1, the electron beam irradiation apparatus 1 includes an irradiation unit 2 that irradiates the mold M with an electron beam, a support unit 3 that movably supports the irradiation unit 2, a differential exhaust unit 4, A control unit 5 that controls the irradiation unit 2 and the support unit 3, and a shield 6 that houses the mold M, the irradiation unit 2, and the support unit 3 therein are provided.

FIG. 2 is a schematic diagram illustrating the configuration of the irradiation unit in FIG.
The irradiation unit 2 irradiates the mold M disposed on the irradiation stage 7 with an electron beam and performs surface treatment such as quenching on the mold M. As shown in FIG. 1, the irradiating unit 2 has an X direction (left and right direction in FIG. 1) that is the left and right direction and a Z direction (up and down direction in FIG. 1) that is the up and down direction. Is supported so as to be movable.

As shown in FIG. 2, the irradiation unit 2 includes an electron beam generation unit (generation unit) 11 that generates an electron beam, and an emission unit 12 that guides and radiates the generated electron beam toward a mold. Is provided.
The electron beam generator 11 is a container whose interior is kept in a vacuum state, for example, 10 ⁻³ Pa by a vacuum pump or the like, and a filament (hot cathode) (not shown) is disposed inside. The filament is supplied with an acceleration voltage for generating an electron beam. Further, the electron beam generator 11 is provided with an electron lens 13 for reducing the beam diameter of the emitted electron beam EB.
The electron lens 13 is a coil formed in an annular shape through which an electron beam passes, and controls a beam diameter and the like by controlling an electric field or a magnetic field in the coil. A method for controlling the electron beam by the electron lens 13 can be a known control method, and is not particularly limited.

  The emission unit 12 includes a pinhole (through hole) 21 that communicates with the electron beam generation unit 11 and opens toward the mold M, and a medium vacuum chamber 22 and a low vacuum chamber 23 that constitute the differential exhaust unit 4. And an ejection part 24 for forming an inert gas jet.

  The pinhole 21 is communicated with the middle vacuum chamber 22 via the through hole 25A, and is communicated with the low vacuum chamber 23 via the through hole 25B. The through hole 25A is formed closer to the electron beam generator 11 than the through hole 25B. Therefore, a pressure gradient is formed in the pinhole 21 to increase the degree of vacuum from the mold M side toward the electron beam generator 11 side.

  The medium vacuum chamber 22 is a space formed on the side surface of the member in which the pinhole 21 is formed, and is a space communicated with the pinhole 21 through the through hole 25A. Further, the intermediate vacuum chamber 22 is connected to the main body of the differential exhaust section 4 disposed outside the shield 6 via the exhaust flow path 26A.

  The low vacuum chamber 23 is a space formed on the side surface of the member in which the pinhole 21 is formed and on the side surface opposite to the side surface on which the intermediate vacuum chamber 22 is provided. The low vacuum chamber 23 communicates with the pinhole 21 through the through hole 25B, and is connected to the main body of the differential exhaust unit 4 through the exhaust passage 26B.

The main body of the differential evacuation unit 4 is disposed outside the shield 6, and the medium vacuum chamber 22 and the low vacuum chamber 23 are respectively brought into a medium vacuum state (for example, 10 Pa) and a low vacuum through the exhaust channel 26 </ b> A and the exhaust channel 26 </ b> B. A state (for example, 1000 Pa) is set.
In addition, as a structure of the differential exhaust part 4, a well-known structure can be used and it does not specifically limit.

FIG. 3 is a partially enlarged view for explaining the configuration of the ejection portion of FIG.
As shown in FIGS. 2 and 3, the jet part 24 includes an outer peripheral part 31 in which a concave part is formed, an adjustment part 32 disposed in the concave part of the outer peripheral part 31, and a supply part 33 that supplies an inert gas. And are provided.
The inert gas supplied from the supply unit 33 is preferably a gas having a low scattering coefficient for the electron beam generated by the electron beam generation unit 11, for example, a gas made of a light element such as helium.

On the inner peripheral surface of the concave portion in the outer peripheral portion 31, a female screw meshed with a male screw formed in the adjusting portion 32 is formed on the mold M side (lower side in FIG. 3), and the electron beam generating portion 11 side ( A wall surface that forms the gas chamber 34 together with the adjusting portion 32 is formed on the upper side of FIG. The supply channel 35 for supplying the inert gas from the supply unit 33 is connected to a position in the outer peripheral portion 31 that communicates with the gas chamber 34.
Furthermore, a convex portion 37 that forms a slit-like nozzle 36 through which inert gas is ejected is formed on the end surface of the concave portion in the outer peripheral portion 31 on the electron beam generating portion 11 side. The outer peripheral surface of the convex portion 37 is an inclined surface that is inclined radially inward toward the mold M side.

The adjustment part 32 is a member formed in a substantially cylindrical shape, and a male screw meshed with a female screw of the outer peripheral part 31 is formed on the outer periphery of the adjustment part 32 on the mold M side. A recess for forming the gas chamber 34 is formed on the 11 side.
Furthermore, the hexagonal shape used when screwing the adjustment part 32 into the outer peripheral part 31 or adjusting the relative position between the outer peripheral part 31 and the adjustment part 32 is provided on the mold M side of the inner peripheral surface of the adjustment part 32. A portion 38 is formed. On the other hand, an inclined surface that forms the nozzle 36 together with the convex portion 37 of the outer peripheral portion 31 is formed on the electron beam generating portion 11 side of the inner peripheral surface of the adjusting portion 32. This inclined surface is a surface inclined inward in the radial direction toward the mold M side.

  The inner peripheral diameter of the nozzle 36 formed by the outer peripheral portion 31 and the adjusting portion 32 is larger than the inner peripheral diameter of the pinhole 21 and the radius is smaller than about 30 mm. Furthermore, it is more desirable that the radius is greater than about 2 mm and less than about 10 mm.

  On the other hand, the ejection angle of the inert gas at the nozzle 36, that is, the inclination angle of the nozzle 36 is desirably an angle within a range of about 10 ° to about 45 ° with respect to the emission direction of the electron beam EB, and more preferably. Is preferably formed within a range of about 15 ° to about 30 °.

  Further, it is desirable that the ejection speed of the inert gas ejected from the nozzle 36 is at least about 50 m / s or more and a sound velocity (about 330 m / s) or less, and more preferably 100 m / s or more and 300 m / s. The following is desirable.

As shown in FIG. 1, the support unit 3 supports the irradiation unit 2 with respect to the mold M so as to be movable in a three-dimensional direction.
The support unit 3 is provided with a portal drive unit 41 that supports the irradiation unit 2 and a traveling unit 42 on which the portal drive unit 41 moves.

The portal drive unit 41 includes a column part 43 extending along the Z direction, which is arranged with the irradiation stage 7 and the mold M interposed therebetween, and a beam part 44 extending along the X direction connecting the upper ends of the column parts 43. And are provided. The irradiation unit 2 is attached to a lower surface, which is a surface facing the mold M in the beam portion 44, so as to be movable in a direction along the beam portion 44, that is, in the X direction and the Z direction.
The configuration of the connecting portion between the beam portion 44 and the irradiation unit 2 can be a known configuration as long as the irradiation unit 2 can move in the X direction and the Z direction, and is not particularly limited.

  The traveling unit 42 is a member extending along the Y direction, which is the front-rear direction, in a region adjacent to the irradiation stage 7, on which the portal drive unit 41 travels. For example, a known member such as a rail can be used as the traveling unit 42.

  The portal drive unit 41 may travel along the traveling unit 42 and move in the Y direction as described above, or may have other known mechanisms that move in the Y direction. It is not limited.

The control unit 5 irradiates a predetermined region of the mold M with an electron beam by controlling the movement of the irradiation unit 2 and the support unit 3 and the irradiation of the electron beam.
The control unit 5 is disposed outside the shield 6, and a signal line 45 extending from the control unit 5 is connected to the support unit 3 and the irradiation unit 2 disposed inside the shield 6.
In addition, about the movement control method of the irradiation part 2 grade | etc., By the control part 5, it demonstrates together in description of the hardening method of the metal mold | die M in the electron beam irradiation apparatus 1 of this embodiment.

As shown in FIG. 1, the shield 6 houses therein an irradiation stage 7, a mold M, a support unit 3 and an irradiation unit 2, and X-rays generated from the mold M irradiated with the electron beam EB. It shields electromagnetic waves. Examples of the material constituting the shield 6 include lead.
The size of the shield 6 may be any size as long as it can secure a space in which the support unit 3 can move after the mold M is placed inside the irradiation stage 7. There is no need to secure space to move in the direction.

  An opening 46 for carrying in and out the mold M is formed on the upper surface of the shield 6, and a lid 47 for closing the opening 46 is disposed in the opening 46. Furthermore, an observation camera 48 for confirming the operation status of the support unit 3 and the irradiation unit 2 and the quenching status of the mold M is disposed inside the shield 6. An image taken by the observation camera 48 is displayed on a monitor (not shown) arranged outside the shield 6.

Next, the operation of the electron beam irradiation apparatus 1 having the above configuration will be described.
First, as shown in FIG. 1, a mold M for performing a surface treatment such as quenching is carried into the shield 6. Specifically, the lid 47 disposed on the upper surface of the shield 6 is removed, and the portal drive unit 41 is moved in the Y direction to form a space for carrying the mold M above the irradiation stage 7. After the mold M is carried into the shield 6 from the opening 46, the opening 46 is closed by the lid 47.

Then, an acceleration voltage etc. are supplied to the filament provided in the electron beam generation part 11 in the irradiation part 2, and an electron beam is produced | generated.
As shown in FIG. 2, the generated electron beam EB is narrowed by the electron lens 13 and emitted from the pinhole 21 toward the mold M through the emission part 12.
In the region irradiated with the electron beam EB in the mold M, the energy of the electron beam EB is converted into heat, so that a quenching process is performed.

Here, the operation in the differential exhaust section 4 and the ejection section 24 will be described.
FIG. 4 is a schematic diagram for explaining a state of ejection of the inert gas in the ejection part of FIG.
When the electron beam EB is irradiated by the electron beam irradiation apparatus 1, a pressure gradient is formed in the pinhole 21 by the differential evacuation unit 4, and the inside of the electron beam generation unit 11 is kept in a high vacuum state. At the same time, as shown in FIG. 4, the inert gas is ejected in a cylindrical shape from the ejection portion 24, and a gas curtain made of the inert gas is formed around the emitted electron beam EB.

  Specifically, as shown in FIGS. 1 and 2, the differential exhaust section 4 exhausts through the exhaust passage 26 </ b> B, the low vacuum chamber 23, and the through hole 25 </ b> B, and the ejecting section 24 side in the pinhole 21. Is in a low vacuum state. On the other hand, the differential exhaust part 4 exhausts through the exhaust passage 26A, the intermediate vacuum chamber 22 and the through hole 25A, and the electron beam generating part 11 side in the pinhole 21 is brought into an intermediate vacuum state.

The supply part 33 of the ejection part 24 supplies an inert gas to the gas chamber 34 via the supply flow path 35 as shown in FIGS. The inert gas that has flowed into the gas chamber 34 passes through the nozzle 36 and is ejected in a cylindrical shape toward the mold M side.
For example, when the ejection speed of the inert gas is about 200 m / s, the dynamic pressure is about 24000 Pa, and the static pressure is reduced by the amount of generated dynamic pressure. That is, the static pressure in the region near the ejection portion 24 in the pinhole 21 is reduced.

Furthermore, when the ejection speed of the inert gas is about 200 m / s, a gas curtain of the inert gas is formed up to about several tens of mm ahead.
The inside of the cylindrical gas curtain is an inert gas atmosphere. When helium gas or the like is used as the inert gas, diffusion of the electron beam EB passing through the inside of the gas curtain is suppressed.

  When the distance between the mold M and the ejection part 24 is kept at a distance that the inert gas gas curtain reaches, the gas curtain collides with the vicinity of the irradiation region of the electron beam EB. Then, the inert gas expels air containing oxygen from around the irradiation region, and an inert gas atmosphere covering the irradiation region is formed.

  According to the above configuration, the inert gas jet is formed in a cylindrical shape toward the mold M in the vicinity of the end of the pinhole 21 on the mold M side. The pressure in the vicinity of the opening is reduced, and the load applied to the differential exhaust unit 4 is reduced. That is, by forming a cylindrical inert gas jet, the static pressure in the region connected to the inside of the jet, that is, the opening of the pinhole 21, is reduced by the dynamic pressure of the jet. As a result, the differential pressure between the end of the pinhole 21 on the generating portion side and the end on the mold M side is reduced, and the load on the differential exhaust portion 4 is reduced. The capacity of the vacuum pump used can be reduced.

  The opening on the mold M side in the pinhole 21 is covered with a cylindrical inert gas jet and is partitioned into an inner side and an outer side by the inert gas jet, so that the gas can be prevented from entering the electron beam generator 11. . For example, as compared with the case where an irradiation window or the like for preventing gas intrusion into the electron beam generator 11 is provided at the end of the pinhole 21, there is nothing to block the electron beam EB. Is prevented. That is, gas inflow to the electron beam generator 11 can be prevented, and scattering of the electron beam EB can be prevented.

Further, the cylindrical inert gas jet becomes a gas curtain and flows toward the mold M while covering the periphery of the electron beam EB. Therefore, the inside of the inert gas jet, that is, the periphery of the electron beam EB can be an inert gas environment.
At this time, when the distance between the mold M and the ejection part 24 is so close that the cylindrical inert gas jet does not diffuse, the inert gas around the irradiation region irradiated with the electron beam EB in the mold M is used. An environment is created. Therefore, deoxygenation of the irradiation region in the mold M can be achieved.

FIG. 5 is a schematic diagram illustrating another configuration of the emitting unit in FIG. FIG. 6 is a schematic diagram illustrating still another configuration of the emitting portion in FIG.
In addition, the structure shown in FIG. 2 may be sufficient as the output part 12, and the structure shown in FIG.5 and FIG.6 may be sufficient, and it does not specifically limit. In the emission part 12 shown in FIG. 6, an exhaust passage 26 </ b> A and an exhaust passage 26 </ b> B are formed in the emission part 12 so as to extend in a direction intersecting with the direction in which the pinhole 21 extends, for example, in a substantially orthogonal direction. In the emission part 12 shown in FIG. 7, a medium vacuum chamber 22 and a low vacuum chamber 23 are formed around the member in which the pinhole 21 is formed. The medium vacuum chamber 22 and the pinhole 21 are connected via a through hole 25A. Communicated. On the other hand, the low vacuum chamber 23 and the pinhole 21 are communicated via the through hole 25B.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the present invention has been described as applied to an electron beam irradiation apparatus that irradiates an electron beam. However, the present invention is not limited to this electron beam irradiation apparatus, and an energy beam such as a laser is irradiated. It can be applied to other various irradiation apparatuses.
Further, although the present invention has been described by applying it to an electron beam irradiation apparatus that irradiates a mold with an electron beam and performs a quenching process, the object to be irradiated with the electron beam is not limited to the mold, and is particularly limited. Not what you want.

It is a schematic diagram explaining schematic structure of the electron beam irradiation apparatus which concerns on one Embodiment of this invention. It is the schematic explaining the structure of the irradiation part of FIG. It is the elements on larger scale explaining the structure of the ejection part of FIG. It is a schematic diagram explaining the ejection state of the inert gas in the ejection part of FIG. It is the schematic explaining another structure of the output part in FIG. It is the schematic explaining another structure of the output part in FIG.

Explanation of symbols

1 Electron beam irradiation device (energy beam irradiation device)
4 Differential exhaust part 11 Electron beam generator (generator)
21 Pinhole (through hole)
24 Ejection part M Mold (irradiated body)

Claims (2)

A generator for generating energy rays;
A through-hole extending from the generating portion toward the irradiated body and through which the energy rays pass toward the irradiated body;
In the through-hole, a differential exhaust part that forms a pressure gradient in which the pressure decreases from the irradiated body side toward the generation part, and
A jet part that forms a cylindrical inert gas jet that covers the periphery of the energy line from the vicinity of the end of the through-hole on the irradiated object side and jets toward the irradiated object;
An energy beam irradiating apparatus characterized in that is provided.   The energy beam irradiation apparatus according to claim 1, wherein the inert gas from the ejection portion is a gas composed of a light element.

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