JPS61259445A - Rotary anode x-ray tube - Google Patents

Abstract

PURPOSE:To prevent a rotary-anode X-ray tube from being broken by heat and enable continuous operation of the device by installing a double-annular heat pipe between an insulating ceramic and a magnetic substance in order to cool the magnetic substance located outside the pipe and block the heat transmitted from inside the pipe by means of a working liquid contained in the pipe. CONSTITUTION:The heat of a rotary anode 2 is carried to the end of a rotary shaft by a monotubular rotary heat pipe 10A and is then transmitted to cooling oil in a cooling oil path 16 by means of a radiation fin group 14. At this point, a working liquid evaporizes on the inner surface of the pipe 10A located in the center of the heated anode 2 to produce a vapor which is condensed at the end of the fin group 14, and the liquid produced by condensation is returned to the evaporation part by centrifugal force and the capillary force of a wick 17 to cool the anode 2. As a magnetic substance 12 is heated although the anode 2 is cooled, a double-annular rotary heat pipe 11 is installed between an insulating ceramic 7 and the magnetic substance 12. The working liquid of the double-annular pipe 11 is located only on the inner surface of its outer case to effectively cool only the magnetic substance 12 located outside the pipe 11, thereby acting as a layer for blocking the heat transmitted from inside.

Description

Detailed Description of the Invention [Technical Field of the Invention] °The present invention provides a rotating anode X-ray tube in which heat generated in the anode during use of the X-ray tube is absorbed by a bearing a! The present invention relates to a technology that transmits heat to the outside without transmitting heat to the structure or drive mechanism, prevents damage to the X-ray tube due to overheating of the anode and shaft in one rotation, and enables continuous operation of the X-ray tube.

[Technical background of the invention]

The conventional structure will be explained with reference to FIG.

FIG. 4 is a conceptual diagram of a rotating anode X-ray tube having a mechanism for supporting a rotating shaft with a magnetic bearing. In the figure, reference numeral 15 denotes a vacuum container that supports the X-ray tube components and keeps the interior vacuumed. Inside the vacuum vessel 15, an umbrella-shaped rotating anode 2 is supported by two magnetic bearing mechanisms 3. Usually, this rotating anode 2
Since a high voltage (+75 KV) is applied to the insulating ceramic shaft 7, the insulating ceramic shaft 7 is connected to the rotating anode 2 so as not to cause demagnetization in the magnetic bearing section. In order to generate X-rays by discharging between the rotating anode 2 and the rotating anode 2, an anode 1 is installed opposite the rotating anode 2.
A drive motor stator 4 and a drive motor coil 5 are arranged around the shaft in order to provide rotational driving force to the rotating anode 2 and the insulating ceramic shaft 7 held in the rotary anode 5 . A magnetic material 12 is wound around the outer periphery of the insulating ceramic shaft 7 in order to generate a holding force for the magnetic bearing 3.

A non-contact displacement meter 6 is installed to detect the displacement of the rotating shaft from the center of rotation and obtain a signal for controlling the magnetic bearing 3. One of the rotating shafts (- indicates that a current introducing shaft 18 is installed passing through the center of the insulating ceramic shaft 7, and a current is applied to the rotating anode 2 from the outside through the electrical contact 8 at the end of the shaft. In addition, an electric contact 8 is installed on the other side of the rotating shaft to ground the electric potential of the magnetic material 12, etc. of the rotating shaft.
．． In order to prevent the drive motor coil 5 and the non-contact displacement 1ti6 from being overheated, a cooling oil circuit 16 is provided.

[Problems with background technology]

Since the X-ray tube in the shed has a small output and the anode is a fixed anode, it is relatively easy to cool down the heat received by discharge (X-ray generation). In the case of a type X-ray tube, cooling is not easy because the output is large and there are rotating parts. Furthermore, an X-ray tube is a type of vacuum tube, and its interior is kept at a high vacuum, so it is difficult to extract a portion of the tube that makes one revolution to the outside due to sealing problems.

Therefore, in general, heat is dissipated by radiation heat transfer between the rotating anode 2 and the vacuum vessel 15, or the heat capacity of the rotating anode (target part) is increased and intermittent operation is performed. This prevents damage due to heat load. However, due to the increase in the output of X-ray tubes and the requirements for continuous use from users of X-ray tubes in medical institutions, etc., there is a need to further actively cool the rotating anode. In particular, when a rotating anode is supported using a magnetic bearing, the upper limit of allowable temperature of the magnetic material installed around the rotating shaft is relatively low, so insulation using ceramic materials or the like is often insufficient.

[Purpose of the invention]

The present invention has been made in consideration of the above problems, and
Introducing active cooling (: therefore.

The object of the present invention is to obtain a rotating anode X-ray tube that can be used continuously and is prevented from being damaged by heat load.

[Summary of the invention]

The rotating anode X-ray tube according to the present invention has a rotating anode that is heated to a high temperature when X-rays are generated, and in order to transfer heat to the shaft end, the rotary anode is moved from the center of the rotating anode toward the shaft end (: One or more single-tube rotation reducing heat vibrators provided, and a heat pipe connected to the opposite side (shaft end side) of the anode of the heat pipe,
A group of fins placed in the X-ray tube vacuum container is used to release heat without contact through radiation heat transfer, and a group of fins located on the outer periphery of the one-rotation shaft from near the bearing and near the drive device toward the end of the shaft. was established. Rotation axis ζ = one or more double annular rotary heat pipes that are concentric with the above-mentioned monotubular rotary heat pipe, and provided on the opposite side (shaft end side) of the anode of this heat pipe, A group of fins planted in a vacuum container is used to release heat without contact through radiation heat transfer between the group of fins, and a group of fins is sandwiched between the single-tube rotary heat pipe and the double-ring type rotary heat pipe. Rotating anode type X characterized by being equipped with a thermal or electrical insulator
It is a wire tube.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention. Also, Figure 2.

FIG. 3 shows a detailed configuration of an embodiment of the present invention. Reference numeral 15 in FIG. 1 is a vacuum container that supports the components of the X-ray tube and keeps the interior vacuumed. Inside the vacuum container 15 (2), an umbrella-shaped rotating anode 2 is supported by two magnetic bearing mechanisms 3.Normally, a high voltage (+75K) is applied to this rotating anode 2.
V), an insulating ceramic shaft 7 is connected to the rotating anode 2 to prevent radiation 4 from occurring at the magnetic bearing portion. In order to cause discharge between the rotating anode 2 and generate X-rays.

An anode 1 is installed opposite a rotating anode 2.

In order to apply rotational driving force to the rotating anode 2 and the insulating ceramic shaft 7, which are held in the vacuum vessel 15 by the magnetic bearing 3, a drive motor stator 4 and a drive motor coil 5 are connected to the shaft periphery. (: placed.

A magnetic material 4412 is wound around the outer periphery of the insulating ceramic shaft 7 in order to generate a holding force for the magnetic bearing 3. In addition, in order to detect the displacement of the rotating shaft from the center of rotation and obtain a signal for controlling the magnetic bearing 3, a non-contact displacement meter 6 is installed from near the center of the rotating anode 2 to both ends of the shaft. On the other hand, two single-tube rotary heat pipes (10 and 10B), one each, are installed at the center of the shaft. These 10 rotating heat pipes are installed from the metal part of the rotating anode 2 through the insulating ceramic bushing 7 to the shaft end, and are connected to an external power source (9 shown) via the electrical contact 8 at the shaft end. ) (: Connected. The electrical contact 8
is held by an insulating ceramic 9. Further, the rotating heat pipe IOB is arranged within an insulating ceramic shaft 7 (bifurcated into two, with a magnetic contact 8 provided at the end similar to the rotating heat pipe 10A) on the side where the 10 rotating heat pipes are located and on the opposite side C. The above rotating heat pipe lQ
A. Near the end of the LOB connected to the 4-air contact point 8, a single-tube rotating heat pipe heat dissipation fin group 14 is fixed, facing the fin group implanted in the vacuum vessel side. ing. A portion 1 which is outside the insulating ceramic shaft (bush) 7 and inside the magnetic body 12 is provided with double annular rotary heat pipes 11 on both shafts (two in total, one each). Near the ends of the double-layered 3j 1m rotary heat pipe 11 (in two places); second, the cooling fin group 13 for the double-circle rotary heat pipe similar to 10 single-tube type rotary heat pipes and 10B is fixed; and faces the fin group implanted in the vacuum vessel 15.The magnetic bearing 3° drive motor stator 4. Drive motor coil 5. Non-contact displacement t
A cooling oil passage 16 is provided so as to surround 'i6.

FIG. 2 is an enlarged view of the portion from the center of the rotating anode to the vicinity of the shaft end in FIG. 1. FIG. 3 shows a BB cross section in FIG. 2. Quicks 17 are fixed to the inner surfaces of the 10 single-tube rotary heat pipes and to the inner surfaces of the outer tube of the double-circle rotary heat pipe.

The operation and effect of the present invention will be explained using FIG. 2. X
The anode 2 is heated for one revolution due to the generation of the line, but the t
At t, heat radiation:;Therefore, there is no other cooling method other than heat radiation.In the present invention, the heat of the rotating anode 2 is transferred to the center of the rotation axis (
: A certain single-tube rotating heat pipe IOA
It is transmitted to the cooling oil inside (indicated by the arrow). At this time,
The working fluid evaporated on the inner surface of the rotating heat pipe 10 (called the evaporation section) in the center of the heated rotating anode 2 condenses on the fin section at the end of the shaft, but this condensed liquid is It is returned to the evaporation section by the capillary force ζ2 of 17. This quick 17 also serves to uniformly wet the inner surface of the evaporation section. As mentioned above, passing the single-tube rotating heat pipe IOA inside the shaft (:Thus, the rotating anode 2 can be cooled, but on the contrary, the magnetic body 12 is heated.
The heavy annular rotating heat pipe 11 is connected to the insulating ceramic 7
(button) and the magnetic body 12. The way heat is transmitted is exactly the same as that of the single tube reduced rotation heat pipe IOA, and the flow is shown by arrow E. 231P-jff
The working fluid of the one-turn heat vibrator 11 exists only on the inner surface of the double-ringed outer container due to centrifugal force and quick movement, so it works effectively only for cooling the magnetic material on the outside (two sides), and only on the inside (axis side). The double-pipe steam space within this double ring serves as a thermal insulation layer for the heat from the heat pipe. Since the rotating anode 2 is cooled by thermal radiation between the fin group and the fin group on the vacuum vessel side, the rotating anode 2 is supported in the vacuum vessel 15 in a non-contact manner by a magnetic bearing 3.
It has no effect on the rotation of.

〔Effect of the invention〕

According to the rotating anode type X-ray tube cooling mechanism according to the present invention, active cooling (Secondly, in a high output rotating anode type X-ray tube,
It can prevent damage due to heat load (secondary damage) and enable continuous use.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, and FIG.
Among the configurations shown in the figures, FIG. 3 is a sectional view of the main parts related to the present invention, FIG. 3 is a sectional view of the rotating heat pipe cooling mechanism taken along the line B-B in FIG. It is a sectional view of a wire tube. 1...Grid electrode 2...Rotating anode (rotor) 3
...Magnetic bearing 4...Drive motor stator 5.
...Drive motor coil 6...Non-contact displacement meter 7...
Insulating ceramic shaft (button) 8...electrical contact
9...Insulating ceramic 10 people...Single tube type rotating heat pipe (11, also used as flow guide and core pole) 10B...Single tube type rotating heat pipe 11...Double ring type rotating heat pipe 12. ...Magnetic material 13...Double annular U-turn heat pipe radiation fin group 1
4...Single tube type rotating heat pipe radiation fin group 15...
・Vacuum container 16...Cooling oil passage 17...Heat pipe quick D...Heat flow from the rotor E...Heat flow from the magnetic material Agent Patent attorney Noriyuki Chika (and 1 other person) )Figure 3

Claims (1)

[Claims] In a rotating anode type 1
Non-radiative heat transfer occurs between one or more single-tube rotating heat pipes and a group of fins installed on the opposite side (shaft end side) of the anode of this heat pipe and planted in the x-ray tube vacuum chamber. A group of fins for discharging heat through contact are provided on the outer periphery of the rotating shaft from near the bearing and near the drive device toward the end of the shaft. One or more double annular rotary heat pipes concentric with the single-tube rotary heat pipe on the rotation axis, and the opposite side of the anode of this heat pipe (
A group of fins installed on the shaft end side) and dissipating heat without contact by radiant heat transfer between the group of fins planted in the vacuum container, and a group of fins installed on the shaft end side and a group of fins installed in the vacuum container, and a group of fins installed on the shaft end side and a group of fins installed in the vacuum container to release heat without contact through radiant heat transfer, and a group of fins installed on the fin group planted in the vacuum container. 1. A rotating anode x-ray tube comprising a thermal or electrical insulator sandwiched between rotating heat pipes.