JPH0622105B2 - Rotating anode X-ray tube - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of a rotary anode X-ray tube used as an X-ray source of an X-ray apparatus.

2. Description of the Related Art In a conventional rotary anode X-ray tube, its anode part is usually constructed as shown in FIG. In this figure, the rotary shaft 3
A rotor 35 is rotatably held by rotatably supporting 1 in a shaft box 34 by bearings 32 and 33, and an umbrella-shaped target 37 is fixed to the rotor 35 via a pillar 36. . A stator 39 is arranged coaxially with the rotor 35 on the outer peripheral portion of the valve (envelope) 38, and the action of the stator 39 causes the rotor 35 to move.
Is rotated, and along with this, the umbrella-shaped target 37
Is rotated.

Problems to be Solved by the Invention By the way, since the short-time rating in this rotating anode X-ray tube depends on the length of the focal track per time, in order to improve this, the target 37 is rotated at a high speed. Alternatively, the diameter of the target 37 must be increased.

However, increasing the rotation speed and increasing the diameter of the target 37 lead to problems of rotation balance and life. That is, when the target 37 has a large diameter, it becomes difficult to balance the rotation, which causes a problem of vibration. In order to prevent this, the rotating shaft 31 and the bearing portion must be increased in size, and in the end, the rotating portion becomes large and heavy, and the life is shortened. Increasing the rotation speed of the target 37 also brings about problems of rotation balance, occurrence of vibration, and shortening of life.

The present invention can improve the short-time rating by increasing the diameter of the target and increasing the length of the focal track per time, and further, the weight of the rotating portion can be reduced, and the rotation balance can be improved. It is an object of the present invention to provide a rotating anode X-ray tube which can have a long life.

Means for Solving the Problems The present invention relates to a rotary anode X-ray tube, wherein an umbrella-shaped target is formed in a donut shape, a support for supporting the same is formed into a cylindrical shape, and the cylindrical support is rotatably supported. The shaft box has a hollow cylindrical shape, and the hollow cylindrical rotor attached to the support is disposed in the hollow portion of the shaft box, and the envelope encloses the outer circumference of the target, support, rotor and cathode. It is intended to cover the inner peripheral side of the hollow portion of the rotor to form a recess and to expose the portion of the axle box to the outside as a constituent part of the axle box. The stator for rotating the rotor is characterized by being arranged in a recess of the envelope located on the inner peripheral side of the rotor hollow portion.

Since the working target is doughnut-shaped, it is easy to increase the diameter, and the focal track per time can be lengthened, so that the short-time rating can be improved. Further, even if the diameter of the target is increased in this way, since the support body that supports the target has a cylindrical shape, the rotating portion does not become heavy as a whole and the rotation balance is good. Furthermore, since the stator for rotating the rotor is arranged in the recess of the envelope located on the inner circumference side of the rotor hollow portion, the outer circumference side of the rotor and the axle box is not surrounded by the stator and is opened, The rotor and the axle box are not thermally confined, and the heat dissipation effect is enhanced. Further, since a part of the envelope is composed of the axle box and the portion of the axle box is exposed to the outside of the envelope, the heat radiation effect in this portion is also improved. Since the heat dissipation effect is enhanced in this way, the long-term rating of the X-ray tube is improved and the load capacity is increased.

Embodiment In FIG. 1, an umbrella-shaped target 11 is formed in a donut shape, and is firmly fixed to a flange 20 of a hollow cylindrical target support body 2 formed of a material having good thermal conductivity. The target support 2 is fixed to the rotor 3 by fixing the target support 2 to the flange 30 of the rotor 3 with the screw 4 at the flange 20. The rotor 3 is formed in a hollow cylindrical shape having a flange 30.

On the other hand, the shaft box 5 is formed in a hollow cylindrical shape, and a cylindrical body 6 made of a good heat conductive material and arranged coaxially with the shaft box 5 is fixed to the tip of the flange 50 thereof.

The hollow-cylindrical rotor 3 is arranged coaxially in the hollow portion of the hollow-cylindrical shaft box 5, and the hollow-cylindrical target support 2 integrated with the rotor 3 is coaxial with the cylindrical body 6. The rotors and the target support 2 and the target 1 which are integrated with the rotors are rotatably supported by the shaft box 5 by the bearings 71 and 72 which are disposed between the shaft box 5 and the rotor 3. .

A first glass cylindrical body 81 is arranged inside the hollow portion of the rotor 3, and one end (the right end in the figure) of the first glass cylindrical body 81 is sealed to the shaft box 5 via a Kovar ring 91. Further, a large-diameter second glass cylindrical body 82 is arranged on the outer peripheral portion of the target 1 and the support body 2, and one end (the right end in the figure) is sealed to one end of the cylindrical body 6 via the Govar ring 101. Has been done. Further, the openings on the other end (right end in the figure) side of these glass cylinders 81, 82 are provided with Kovar rings 92, 1
It is closed by the doughnut-shaped lid 11 sealed with 02. Thus, the first and second glass cylinders 81, 82,
An envelope (valve) for covering and sealing the target 1, the rotor 3 and the like is formed by the lid body 11, the axle box 5, and the cylindrical body 6 integrated with the axle box 5. The lid body 11 has a cathode assembly 13
Is sealed by a Kovar ring 14, and the cathode 15 supported by the cathode structure 13 extends through the opening 110 provided in the lid 11 into the envelope and faces the target 1. is doing.

This envelope has a recess (which penetrates in this embodiment) A formed by the hollow portion of the first glass cylindrical body 81,
It has the axle box 5, its flange 50 and the recess B formed by the cylindrical body 6.

Then, in the recess A, the stator 12 is disposed coaxially with the rotor 3 at a position facing the rotor 3. The rotor 12 is rotated by the stator 12, and the support 2 and the target 1 are rotated accordingly.

Since the target 1 is doughnut-shaped in this way, it is easy to increase the diameter, and the focal track per time can be lengthened, so that the short-time rating can be improved. Further, even if the target 1 is increased in diameter in this way, the rotating parts such as the support 2 and the rotor 3 supporting the target 1 are cylindrical, so that the rotating part is not heavy as a whole and can be made lightweight. The rotation balance is also good. for that reason,
A long life can be achieved.

The stator 12 is arranged outside the envelope, but since it is arranged in the recess A of the envelope formed in the hollow portion of the hollow cylindrical rotor 3, the rotor 3 and the bearing portion thereof are provided. The outer peripheral side of each is open without being surrounded by the stator 12, and the heat thereof is not trapped by the stator 12. That is, the radiation efficiency of heat of the rotor 3 and its bearing portion is increased. By improving the thermal emissivity in this way, the long-term rating can be improved and the load capacity can be increased.

Furthermore, as described above, the envelope is made of glass cylinders 81, 82.
Is formed by sealing it to the lid body 11 via the Kovar rings 92 and 102, but the shaft box 5 is exposed to the outside by using the shaft box 5 as its constituent part. In the case of this embodiment, the outer peripheral side of the axle box 5 is a recess B opened to the outside. Therefore, the heat conducted to the shaft box 5 is radiated to the outside from the recess B, and the heat dissipation effect is enhanced. In addition, in this embodiment, the recess B is a space surrounded by the outer peripheral surface of the shaft box 5, the flange 50 of the shaft box 5, and the inner peripheral surface of the cylindrical body 6, and conducts to the support body 2. The generated heat is radiated from the recess B through the cylindrical body 6, and the heat dissipation effect is also improved in this respect.

It is not necessary that the entire target 1 is made of a high melting point substance, but only the electron impact surface may be made of a high melting point substance or a vapor deposition film thereof, and the rest may be made of a low melting point substance.

Further, the target support 2 and the rotor 3 shown in FIG. 1 may be integrally formed, and in some cases, the target 1, the support 2 and the rotor 3 may be integrally formed. In this case, in order to reduce the weight, it is advantageous to vapor-deposit only the electron impact surface with a high melting point substance.

Further, in FIG. 1, the shaft box 5 is a hollow cylinder and the recess A is a through opening, but the shaft box 5 may be a bottomed cylinder and the recess A may be a bottomed recess.

FIG. 2 shows another embodiment, but the cooling effect is improved by providing the cooler 16 on the outer peripheral portion of the outer glass envelope 82. Other configurations are the same as in FIG.
Since the shape is merely slightly changed, the corresponding portions are designated by the corresponding reference numerals and the description thereof will be omitted.

A cooler such as the cooler 16 shown in FIG. 2 can be provided at a place such as the recess B in the case of FIG.

EFFECTS OF THE INVENTION In the rotating anode X-ray tube according to the present invention, since the target is donut-shaped, the diameter can be easily increased, and the focal track per time can be lengthened, so that the short-time rating can be improved. . In addition, even if the target diameter is increased in this way, the rotating shaft that supports it has a cylindrical shape, so the rotating part is not heavy as a whole and can be lightened, and the rotation balance is good, and the life is long. it can. further,
Since the stator for rotating the rotor is arranged in the recess of the envelope located on the inner peripheral side of the rotor hollow portion, the outer peripheral side of the rotor and the axle box is not surrounded by the stator,
Since it is opened, the rotor and the shaft box are not thermally confined, and the heat dissipation effect is enhanced. Further, since a part of the envelope is composed of the axle box and the portion of the axle box is exposed to the outside of the envelope, the heat radiation effect in this portion is also improved. Since the heat dissipation effect is enhanced in this way, the long-term rating of the X-ray tube is improved and the load capacity is increased.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a sectional view of another embodiment, and FIG. 3 is a sectional view of a conventional example. 1, 37 ... Target, 2 ... Target support 3, 35 ... Rotor, 5, 34 ... Shaft box 71, 72, 32 ... Bearing 81, 82 ... Glass cylinder 12, 39 ... Stator, 13 ... Cathode structure 15 ... Cathode, 16 ... Cooler

Claims (1)

[Claims] 1. An umbrella-shaped target formed in a donut shape, a cylindrical support for supporting the target, a hollow cylindrical shaft box for rotatably supporting the cylindrical support, and A hollow cylindrical rotor that is attached to a support body of the rotor and that is disposed in the hollow portion of the shaft box, a cathode that is disposed to face the target, and a recess that covers the inner peripheral side of the hollow portion of the rotor. And an envelope that covers the target, the support, the rotor, and the outer peripheral side of the cathode so as to expose the portion of the shaft box to the outside while forming the shaft box as a constituent part, and the rotor hollow. A rotating anode X-ray tube, comprising: a stator for rotating the rotor, which is arranged outside the envelope in a recess of the envelope located on the inner peripheral side of the unit.