JPH0629885Y2 - Electron gun - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an electron gun used in an electron beam irradiation device and the like.

(Prior Art) In this type of electron gun, a linear filament 3 made of, for example, tungsten is installed inside a shield tube 2 having an irradiation opening 1 as shown in the figure, facing the irradiation opening 1. It is already well known that the electron beam is emitted by heating the. For the fixed installation of the filament 3, a pair of holding plates 4 facing each other is prepared, and each end of the filament 3 is attached by an attachment mechanism 5 supported by the holding plates 4.

FIG. 3 shows a conventional attachment mechanism 5, 7 is an insulating base fixed to the holding plate 4 by bolts 6, 8 is a connecting conductor for connecting adjacent filaments, and also serves as attachment of the filament 3. , 9 are fittings, which are fixed to the connecting conductor 8 with bolts 10. The filament 3 is fixed so that its end portion penetrates a hole 11 provided in the insulating base 7 and its tip end is sandwiched between the connecting conductor 8 and the mounting fitting 9.

The mounting positions of the filaments 3 are restricted by the mounting mechanisms 5 that are facing each other and that mount the ends of the filaments 3 as follows. First, a step 12 is formed on the surface of the insulating base 7 along the direction orthogonal to the longitudinal direction of the filament 3. And this step 1
The connecting conductor 8 is engaged with 2, and in this case, the front surface of the connecting conductor 8 facing the other facing mounting mechanism 5 side is engaged with the step portion 12. By this engagement, the position of the filament 3 in the longitudinal direction is regulated. In addition, the filament 3 has a hole 11 formed in the insulating base 7.
By penetrating through, the position of the filament 3 in the direction orthogonal to the longitudinal direction is regulated.

As described above, the position of the filament 3 is regulated, which is convenient.
Since it is inserted into the hole 11 of the above, heat easily escapes from the filament 3 to the insulating base 7 through the hole 11. Further, due to this heat, the filament 3 and the insulating base 7 are welded to each other, so that the filament 3 is apt to be melted, which causes the life of the electron gun to be shortened.

(Problems to be Solved by the Invention) This invention aims at enabling the filament position regulation so as to avoid the heat dissipation of the filament and to prolong the life of the filament.

(Means for Solving the Problems) The present invention is directed to a bottom surface of a connecting conductor, the front surface of which faces the other mounting mechanism facing the stepped portion of the insulating base, and the bottom surface of the connecting conductor facing each other. One of the surfaces of the insulating base has a concave portion, and the other has a convex portion fitted in the concave portion and having a top surface to form a gap between the concave portion and the inner surface of the concave portion along the longitudinal direction of the filament. An end portion of the filament that is provided and straddles the front end portion of the insulating base on the other attachment mechanism side from the step portion is placed on the surface of the connection conductor and fixed by being sandwiched by attachment fittings. And

(Embodiment) An embodiment of the present invention will be described with reference to FIGS. 1 and 2.
In addition, the same reference numerals as those in FIG. 3 indicate the same or corresponding portions. Of the connecting conductor 8 on the stepped portion 12 of the insulating base 7,
The position regulation along the longitudinal direction of the filament 3 is performed by engaging the front surface facing the other mounting mechanism facing each other, as in the case of FIG.

According to this invention, the details are as shown in FIG.
A concave portion 15 is formed on the bottom surface of the connecting conductor 8 along the longitudinal direction of the filament 3, and a convex portion 16 is formed on the surface of the insulating base 7 facing this bottom surface. Then, the convex portion 16 is fitted into the concave portion 15.

Further, in this fitted state, the top surface of the convex portion 16 and the concave portion 15
A gap 17 is formed between the inner surface and the inner surface.
Therefore, the convex portions 16 and the concave portions 15 come into close contact with each other on their respective side surfaces.

The end portion of the filament 3 does not pass through the hole 11 of the insulating base 7 as shown in FIG. 3 and straddles above the front end portion of the insulating base 7 on the side of the other mounting mechanism 5 facing the stepped portion 12. Then, it is placed on the surface of the connection conductor 8. Then, they are fixed so as to be sandwiched by the fittings 9.

In the above configuration, the attachment position along the longitudinal direction of the filament 3 is regulated by the engagement between the step portion 12 of the insulating base 7 and the front surface of the connection conductor 8. This is similar to the case of FIG.

The mounting position of the filament 3 along the direction orthogonal to the longitudinal direction is restricted by the fitting of the recess 15 of the connecting conductor 8 and the projection 16 of the insulating base 7. Therefore, it is not necessary to insert the filament 3 into the hole of the insulating base 7 to regulate the position as in the conventional case.

On the other hand, since it is not necessary to insert it into the hole of the insulating base 7 as described above, heat from the filament 3 is not transferred to the insulating base 7, and the insulating base 7 and the filament 3 may be welded to each other. Disappear.

Even if the heat of the filament 3 is transferred to the mounting member 9 and the connecting conductor 8, the connecting conductor 8 and the insulating base 7 are in contact with each other only on the respective side surfaces of the concave portion 17 and the convex portion 15. Therefore, heat dissipation to the periphery of the filament 3 is reduced as much as possible.

As described above, the position of the attachment mechanism 5 along the longitudinal direction of the filament 3 and the direction orthogonal thereto is properly regulated, and the attachment also prevents welding of the filament 3 and the insulating base 7 and dissipation of heat to the surroundings. It becomes.

Instead of the embodiment shown in the figure, the convex portion 16 may be formed on the connecting conductor 8 and the concave portion 15 may be formed on the insulating base 7.

(Effects of the Invention) As described in detail above, according to the present invention, the filament attachment position is regulated, and filament welding and heat dissipation can be reliably avoided.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a partially enlarged perspective view, and FIG. 3 is a partially cutaway perspective view of a conventional example. 1 ... Irradiation port, 2 ... Shield tube, 3 ... Filament, 4 ... Holding plate, 5 ... Mounting mechanism, 7 ... Insulating base, 8
...... Connecting conductor, 9 ...... Mounting bracket, 12 ...... Step, 15 ...
… Concave part, 16 …… projection part, 17 …… gap,

Claims (1)

[Scope of utility model registration request] 1. A shielded tube having an electron beam irradiation port is provided with a pair of holding plates facing the irradiation port and facing each other. Each holding plate is provided with each end of a filament for emitting an electron beam. In an electron gun provided with a mounting mechanism for mounting, each of the mounting mechanisms is provided on the side of the other mounting mechanism that faces an insulating base having a step portion formed on the surface thereof along a direction orthogonal to the longitudinal direction of the filament. A front surface facing the connection conductor engaged with the step portion of the insulating base;
An end of the filament straddling the front end of the insulating base on the side of the other mounting mechanism facing the stepped portion is constituted by a mounting metal fitting that is fixed so as to be sandwiched between the surface of the connecting conductor. A bottom surface of the connection conductor,
A concave portion is formed on one of the surfaces of the insulating base where the bottom surfaces face each other, and a convex portion that is fitted into the concave portion on the other side and has a top surface that forms a gap between the concave surface and the inner surface of the concave portion. An electron gun provided along the longitudinal direction of the filament.