JP2002130280A - Bearing structure for rotational mechanism, and mounting method and device for the mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly rotate a rotor made from a heavy-weight material at a high-speed revolution, relating to a bearing structure for a rotational mechanism, and to provide a mounting method and a device for the mechanism. SOLUTION: The bearing structure for a rotational mechanism is configured, such that the peripheral surfaces of a rotor section 1 and a fixing section 2 that holds the rotation of the rotor section are made to oppose each other, interposing a specified gap G which has the same concentricity as with the rotor section and the fixing section; a field-developing section 3 is formed on either of the peripheral surfaces, and a superconducting section 4 is formed at another peripheral surface; and a field H existing in the gap G is made uniform in the direction of periphery a of the rotor section 1, but is made nonuniform in the direction of the axis z.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing structure for a rotating mechanism, a method of mounting the same, and a device therefor, and more particularly, to a method for suitably rotating a rotating body made of a heavy object at high speed and smoothly.

For example, in a medical X-ray CT apparatus, it is necessary to rotate a scanning gantry, which is a heavy object, at a relatively high speed. However, in order to properly obtain a CT tomographic image of a fast-moving organ such as the heart. It is desired that the scanning speed (scan time sec per gantry rotation) be further increased (reduced).

[0003]

2. Description of the Related Art FIG. 12 is a view for explaining a conventional technique, and shows a main part of a conventional X-ray CT apparatus (scanning gantry section). FIG. 12A is a front view, and FIG. 12B is a side view thereof.

In the figure, reference numeral 61 denotes an X-ray fan beam XL.
Axial / Herical scan of subject 100 by FB
A scanning gantry (rotating unit) 20 for reading, 20 is the subject 10
12 is an imaging table to be moved in the direction of the body axis CLb (however, in FIG. 12 (A), in a direction perpendicular to the plane of the drawing), 40 is a rotating anode type X-ray tube, and 50 is an X-ray irradiation range. Collimator for limiting (mainly in the body axis CLb direction), 7
0 is a large number arranged in the channel CH direction (n = about 1000)
X-ray detector array in which the X-ray detectors are arranged in one or more rows in the body axis direction, 91 is a bearing mechanism (fixing portion) that freely supports the rotation of the scanning gantry 61, and 92 is a bearing. Reference numeral 93 denotes a motor serving as a rotary drive source, reference numeral 94 denotes a pulley fixed to a rotation shaft of the motor 93, and reference numeral 95 denotes a belt for transmitting the rotary driving force of the pulley to the scanning gantry 61.

[0005] With this configuration, when the user confirms the scan plan and presses the start button, the motor 93 starts rotating, and when the scanning gantry 61 reaches a certain rotational speed, scanning and reading of the subject 100 starts. I do.

[0006]

However, when the gantry rotating portion 61 is supported by the bearing 92 as in the above-mentioned conventional system, the scanning time per gantry rotation is 0 due to bearing friction in the bearing portion. .5se
c was the limit.

[0007] This problem is not limited to the X-ray CT apparatus described above, but can be applied to, for example, an MR apparatus and other various apparatuses that need to rotate a heavy object at high speed and smoothly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a bearing structure of a rotating mechanism capable of rotating a rotating body made of a heavy object at high speed and smoothly. An object of the present invention is to provide a mounting method and an apparatus therefor.

[0009]

The above-mentioned problem is solved, for example, by referring to FIG.
Is solved. That is, in the bearing structure of the rotating mechanism of the present invention (1), the rotating part 1 and the fixed part 2 supporting the rotation of the rotating part are relatively positioned with respect to each other with a predetermined concentric gap G interposed therebetween. A magnetic field generating portion 3 on one circumferential surface and a superconductor portion 4 on the other circumferential surface, and a magnetic field H existing in the gap G extends in a circumferential direction a of the rotating portion 1. It is configured to be uniform and non-uniform in the axial direction z.

In the above description, 1 is a rotating part and 2 is a fixed part. However, the present invention is not limited to this. Conversely, 2 is the rotating part and 1
May be used as the fixed part. In this case, in the bearing structure of the rotating mechanism of the present invention (1), the rotating part 2 and the fixed part 1 supporting the rotation of the rotating part are formed so that their respective circumferential surfaces are sandwiched by a predetermined concentric gap G. A magnetic field generating unit 3 on one of the circumferential surfaces and a superconductor unit 4 on the other circumferential surface,
The magnetic field H existing in the gap G is uniform in the circumferential direction a of the rotating portion 2 and non-uniform in the axial direction z.

For the same reason as described above, any one of the magnetic field generating section 3 and the superconductor section 4 may be provided in the rotating section or the fixed section, as long as they face each other.

In the present invention (1), the gap G
By configuring the magnetic field H existing therein to be uniform in the circumferential direction a of the rotating part and non-uniform in the axial direction z,
The interaction (preferably the pinning action of the magnetic flux) generated between the magnetic field generating section 3 and the superconductor section 4 can be effectively used for the bearing action (function) in the rotating mechanism section. That is, according to the above configuration, the rotating portion is supported by the fixed portion in a floating manner, and the movement (shake) of the rotating portion in the z-axis direction is effectively restrained by the interaction with the non-uniform magnetic field, and Is freely movable by interaction with a uniform magnetic field.

Therefore, according to the present invention (1), it is possible to rotate various kinds of rotating bodies made of general heavy objects at high speed and smoothly.

Preferably, in the present invention (2), in the above-mentioned present invention (1), the magnetic field generating portion comprises a permanent magnet.

Preferably, in the present invention (3),
In the present invention (1) or (2), the magnetic field generator alternately generates N-pole and S-pole magnetic fields in the axial direction of the rotating part. Therefore, a non-uniform magnetic field can be effectively generated in the axial direction of the rotating part.

Preferably, in the present invention (4),
In the present invention (3), the magnetic field generation unit includes a magnetic body for passing a magnetic flux from the N pole to the S pole on the surface opposite to the facing gap. Therefore, the magnetic field H in the gap G increases, and a larger pinning force (contributing to buoyancy and restraining force) can be generated.

Preferably, in the present invention (5), in the above-mentioned present invention (1), the superconductor portion is made of a type 2 superconductor (a so-called high-temperature superconductor). Therefore, a useful magnetic flux pinning action can be obtained at a relatively high temperature.

The mounting method of the bearing structure according to the present invention (6) is the mounting method of the bearing structure according to the present invention (1), wherein the rotating part is positioned on the fixed part by using an external support. Then, in this state, the superconductor is cooled to a predetermined temperature while maintaining the magnetic field in the gap at a predetermined amount, and after the pinning action of the required magnetic flux in the superconductor is obtained, the external support is removed. Is for supporting the rotating part by the fixed part by the pinning action of the magnetic flux.

Further, the computer tomography apparatus of the present invention (7) comprises a rotating section for rotationally scanning and detecting a signal for obtaining a tomographic image of a subject (person or object), and a fixed section for supporting the rotation of the rotating section. And the supporting surfaces are opposed to each other with a predetermined gap on a concentric circle, and a magnetic field generating portion is provided on one of the circumferential surfaces, and a superconductor portion is provided on the other circumferential surface. ,
The magnetic field present in the gap is configured to be uniform in the circumferential direction of the rotating portion and non-uniform in the axial direction.

Preferably, in the present invention (8), in the above-mentioned present invention (7), a rotating part in which the X-ray tube and the X-ray detector array face each other with the subject interposed therebetween; And a supporting unit for reconstructing a CT tomographic image of the subject based on a detection signal of the X-ray detector array.

Therefore, the scanning speed (scan time per one rotation of the gantry) is further increased (reduced).
This makes it possible to properly acquire a CT tomographic image of a fast-moving organ such as the heart.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the same reference numerals indicate the same or corresponding parts throughout the drawings.

FIG. 2 is a block diagram of a main part of an X-ray CT apparatus according to the embodiment. The apparatus is roughly divided into a scanning gantry section 30 for performing an Axial / Herical scan / read of the subject 100 using an X-ray fan beam XLFB. And an imaging table 20 on which the subject 100 is placed and moved in the body axis direction, and a remote operation console unit 10 operated by a user.

In the scanning gantry section 30, 31 is a fixed section of the scanning gantry, 61 is a rotating section of the scanning gantry, 40
Is a rotating anode type X-ray tube, 40A is an X-ray control unit, 50 is an X-ray tube.
A collimator 50A for limiting the radiation range of the line {mainly in the direction of the body axis CLb (corresponding to the direction perpendicular to the paper surface in FIG. 2)}
Denotes a collimator control unit; 70, an X-ray detector array in which a large number (about n = 1000) of X-ray detectors arranged in the channel CH direction are arranged in one or more rows in the body axis direction;
Is the subject 10 based on the detection signal of the X-ray detector array 70.
Data collection unit (DA) for generating and collecting projection data
S) and 61A are rotation control units of the gantry rotation unit 61.

In the operation console 10, reference numeral 11 denotes a central processing unit for performing main control and processing (scan control, CT tomographic image reconstruction processing, etc.) of the X-ray CT apparatus, and 11a denotes its CP.
U and 11b are main memories (MEM) including RAM, ROM and the like used by the CPU 11a, 12 is a command and data input device including a keyboard and a mouse, and 13 is a scan plan and a CT tomogram of a scan result are displayed. Display device (CRT) 14, a control interface for exchanging various control signals CD and monitor signals MD between the CPU 11a and the scanning gantry unit 30 and the imaging table 20,
Reference numeral 15 denotes a data collection buffer for temporarily accumulating projection data from the data collection unit 80. Reference numeral 16 denotes various application programs and various computations / operations required for operating the X-ray CT apparatus.
It is a secondary storage device (such as a hard disk) that stores a data file for correction and the like.

With this configuration, the fan beam XLFB from the X-ray tube 40 passes through the subject 100 and is incident on the X-ray detector array 70 all at once. The data acquisition unit 80 integrates and A / D converts each detection signal of the X-ray detector array 70 to generate corresponding projection data, and stores them in the data acquisition buffer 15. Further, the gantry rotating unit 61 performs the same projection in each view slightly rotated, and thus collects and accumulates projection data for one rotation of the scanning gantry.

Further, the imaging table 20 is moved intermittently / continuously in the body axis direction of the subject 100 in accordance with the axial / helical scan method, and thus all projection data of a required imaging area of the subject 100 is collected and accumulated. Are finally stored in the secondary storage device 16. And
When the scan is completed, the CPU 11a reconstructs a CT tomographic image of the subject 100 based on all the obtained projection data and displays the CT tomographic image on the display device 13. Next, an embodiment of the bearing mechanism according to the present invention will be described in detail.

FIGS. 3 and 4 are main configuration diagrams (1) and (2) of the scanning gantry section according to the embodiment. FIG. 3 (A) is a front view of the scanning gantry section, and FIG. FIG.

In FIG. 3, reference numeral 5 denotes a gantry bearing mechanism using a superconductor, and a magnet provided on the rotating portion 61 side.
The case where the (layer) is supported by a so-called magnetic flux pinning action by a superconductor (layer) provided on the fixed portion 31 side is shown. Here, reference numeral 32 denotes a container (a non-magnetic material such as ceramics or rigid resin) having a rectangular shape in cross section embedded along the inner peripheral support surface of the fixing portion 31, and reference numeral 33 is provided so as to cover the entire inner wall of the container 32. Heat insulation layer (polytetrafluoroethylene, etc.), 3
Reference numeral 4 denotes a superconductor (a second type superconductor, a high-temperature superconductor, or the like) having a rectangular shape in cross section fixed (adhered or the like) to the outer peripheral surface of the heat insulating layer 33 on the rotation axis side, and 35 is filled in the heat insulating layer 33. A coolant (liquid nitrogen or the like) 62 is a magnet (a permanent magnet or the like) embedded along the outer peripheral support surface of the rotating unit 61. With such a configuration, the gantry rotating unit 61 is magnetically levitated and supported by the gantry fixing unit 31, and is rotatably supported around the body axis CLb.

FIG. 4A is a side sectional view of the scanning gantry.
FIG. 4B shows a rear view thereof. FIG.
(A) is the same as FIG. 3 (B). In FIG.
Reference numeral 6 denotes a rotation drive unit using an induction linear motor system, which shows a case where a secondary conductor provided on the gantry rotation unit 61 side is driven to rotate by a linear (rotational) magnetic field by a coil provided on the gantry fixing unit 31 side. I have. Here, reference numeral 63 denotes a disk-shaped secondary conductor plate (iron, aluminum, copper, or the like) provided on the back side of the gantry rotating unit 61, and reference numeral 36 denotes a portion corresponding to the secondary conductor 63 on the front side of the gantry fixing unit 31. It is a provided coil. With this configuration, when the N / S pole of the coil 36 rotates at a constant speed in the direction of the arrow a, the secondary conductor 63 rotates following the rotation.

FIGS. 5 to 7 are explanatory views (1) to (3) of the operation of the gantry bearing mechanism according to the embodiment, and FIG. 5A is a typical type 2 superconductor used in the embodiment. FIG. 5B shows a typical temperature characteristic, and FIG.

The superconductor includes a first type superconductor and a second type superconductor according to the mode of change of the internal magnetic flux density B (= μ ₀ H) when increasing / decreasing the magnetic field Ha applied thereto.
Incidentally, many high-temperature superconductors reported today are included in this type 2 superconductor.

In FIG. 5 (A), when the temperature T is lowered in the state of the external magnetic field Ha = 0, the second type superconductor enters a superconducting state (resistance r = 0) below the critical temperature Tc. In this state, even if the external magnetic field Ha is increased within the range of the first critical magnetic field H _c1 , the magnetic flux B (= μ ₀
H) cannot penetrate into the superconductor.

In this state, when the external magnetic field Ha is increased and eventually exceeds the first critical magnetic field H _c1 , the resistance r = 0 remains, and
Part of the magnetic flux B enters the inside of the superconductor (defect / incomplete part of crystal, etc.). This state is called a mixed state, and a pinning action of the magnetic flux (an action of holding the invading magnetic flux B as it is) described later occurs.

Further, in this state, when the external magnetic field Ha is further increased and eventually exceeds the second critical magnetic field _Hc2 , a normal conduction state (r ≠ 0) is established. Here, the critical temperature Tc is the maximum temperature at which the superconducting state is maintained when the external magnetic field Ha (and the internal current I) is 0, and the critical magnetic field Hc is the superconducting state when the temperature T (and the internal current I) is 0. Is defined as the highest magnetic field.

In FIG. 5B, in the first-class superconductor, a magnetizing current -I (= Ha) that immediately cancels the external magnetic field Hc from when the critical magnetic field Hc is lower than the critical magnetic field Hc suddenly flows. Is always zero. On the other hand, in the type 2 superconductor, the magnetization current −I in the direction of canceling the external magnetic field H _c2 gradually starts flowing when the magnetic field falls below the second critical magnetic field H _c2 ,
Thus, the magnetic flux B inside the superconductor starts to decrease. When the external magnetic field Ha further decreases and eventually falls below the first critical magnetic field _Hc1 , the internal magnetic flux B becomes zero, and the subsequent operation is the same as that of the first type superconductor. The effect when the external magnetic field Ha is increased is opposite to the above. Therefore, in the present embodiment, such a type 2 superconductor is used in a mixed state.

FIG. 6A shows a conceptual configuration diagram of the gantry bearing mechanism. Here, the gantry rotating part 61 and the gantry fixing part 31 face each other with a predetermined concentric gap therebetween, and the magnet 62 and the gantry fixing part are fixed on the circumferential surface of the gantry rotating part 61. The superconductor 34 is provided on the circumferential surface of the portion 31. As shown in the figure, for example, the magnet 62 has a ring composed of only N poles on the surface side and a ring composed of only S poles on the surface side arranged alternately in the direction of the body axis CLb. As a result, the magnetic field H existing in the gap is uniform in the circumferential direction of the gantry rotating unit 61 and non-uniform in the z-axis direction.

FIG. 6B is a partially enlarged view of a region A in FIG. 6A. In a mixed state of the superconductor 34, and the superconducting current -I _N so as to prevent the penetration of magnetic flux N from N pole, S
Superconducting current that prevents the intrusion of magnetic flux S toward the pole-
And I _S is flowing. In a defective portion (incomplete portion) where a part of the magnetic flux N / S has entered, local currents corresponding to the magnetic flux N / S flow.

When a magnetic flux passes through the defective portion, an electromagnetic force according to Fleming's left-hand rule acts between the magnetic flux and the superconducting current, so that a force acts on a cylinder supporting the magnetic flux. Moves, it means that kinetic energy is consumed, in other words, resistance r 抵抗 0 is generated inside the superconductor. However, since the resistance r = 0 in the mixed state, it is considered that some stopping force acts inside the superconductor, and it is understood that this causes a pinning force of the superconductor. As described above, the principle of the pinning action is not necessarily clear, but generally, the magnetic flux (density) penetrating into the above-described incomplete portion is stored in a mixed state and acts in a direction in which the magnetic flux density becomes constant (restoring force). ) Is understood to work. Under such circumstances, the operation of the gantry bearing in the present embodiment will be described next.

FIG. 7A is a top sectional view of the gantry bearing mechanism 5. Looking at the structure to the body (z) axially with N and S poles of the magnet 64, preferably across the non-magnetic layer 64 having a predetermined thickness, they are arranged alternately, thereby the gap G _U The middle magnetic field φz is not uniform in the z-axis direction. For example, it has a substantially sinusoidal shape as shown. In this state, most of the magnetic flux N / S cannot enter the superconductor 34 due to the Meissner effect, but some of the magnetic flux φ ₁ ,
The φ ₂ or the like penetrates into a defect or the like and is pinned (restricted, stored, etc.) so as to keep the respective magnetic flux constant.

Focusing on the magnetic flux N, the magnetic field near the center of the N pole is relatively high. When a part of the magnetic flux φ ₁ enters the defect, the magnetic flux density φ ₁ is kept constant at the defect. Pinning force works to keep. On the other hand, the magnetic field near the N extreme part is relatively low, and when a part of the magnetic flux φ ₂ (<φ ₁ ) enters the defect, the defect is pinned to keep the magnetic flux density φ ₂ constant. Power works. The same applies to the south pole.

Accordingly, a restoring force always acts in the z-axis direction of the rotating portion 61 to keep the positional relationship between the defective portion and the magnet 62 constant, whereby the rotating portion 61 separates or shakes in the z-axis direction. Can be effectively prevented.

Similarly, due to the pinning action, the magnetic flux φ ₂ having a gradient component of the magnetic flux with respect to the superconductor 34 generates a force in the direction of pulling up the rotating portion 61 against gravity. In other words, if the rotating portion 61 is going to be lowered by gravity, the number of constrained magnetic fluxes φ ₂ of the defective portion decreases, and a force acts in a direction to lift the rotating portion 61 to compensate for the decrease. Also, if the rotating portion 61 attempts to go up with some force, the number of constrained magnetic fluxes φ ₂ of the defective portion increases,
To compensate for this, a force acts in a direction to pull down the rotating part 61. Furthermore, the magnetic flux phi ₃ which can not be entering the internal superconductor by the Meissner effect acts as a cushion force because it does not narrow the upper part of the gap G _U. Thus, a constraint force in the y-axis direction (a suspension force against gravity) and a constraint force in the z-axis direction (restoring force against blur) in the upper gantry bearing mechanism are generated.

FIG. 7B shows the gantry bearing mechanism 5.
When the structure is viewed from the direction of the body (z) axis, the N poles are uniformly and densely arranged in the circumferential direction of the rotating portion 61. The magnetic field φc in _U is uniform in the direction of rotation. Although not shown,
The same applies to the S-pole ring. Accordingly, the magnetic fluxes φ ₁ , φ _2, etc. penetrating into the defective portion are also uniform in the respective rotation directions, so that the pinning action does not occur in the rotation direction of the rotating portion 61. That is, the rotating portion 61 in this case can freely rotate in the rotating direction.

FIG. 7C is a sectional view of the lower portion of the gantry bearing mechanism 5, and its operation appears in the z-axis direction in the same manner as in FIG. 7A. In the y-axis direction, it appears symmetrically with the case of FIG. 7A. That is,
Now, when the rotating part 61 is going to be lowered by gravity, the number of constrained magnetic fluxes φ ₄ of the defective part increases, so that a force acts in a direction to push up the rotating part 61 in order to compensate for this. The rotating unit 6
If 1 attempts to rise with some force, the number of constrained magnetic fluxes φ _{4 at the} defective portion decreases, and a force acts in the direction of pulling down the rotating portion 61 to compensate for this. Further, the magnetic flux phi ₅ that can not penetrate into the internal superconductor by the Meissner effect acts as a cushion force because it does not narrow the lower part of the gap G _D. Thus, a restraining force in the y-axis direction (lifting force against gravity) and a restraining force in the z-axis direction (restoring force against blur) in the lower gantry bearing mechanism are generated.

Although not shown, the pinning force at the left and right portions of the rotating portion 61 does not contribute to the buoyancy of the rotating portion 61, but acts to restrain the rotating portion 61 from moving in the left-right direction. Needless to say, the rotation portion 61 is restrained from moving in the z-axis direction at its left and right portions.

Thus, according to the present embodiment, the gantry rotating section 61 is supported so as to be able to rotate freely and smoothly at high speed in the rotating direction while its movement in the z-axis direction is restricted.

In the above embodiment, the N-pole and S-pole rings are alternately arranged at substantially equal intervals in the z-axis direction of the gantry rotating portion 61, but the present invention is not limited to this. As long as the magnetic flux density φz in the z-axis direction becomes non-uniform, a pinning action can be generated by the same principle as described above, and the specific structure is not limited. For example, a pair of N and S pole rings may be disposed at substantially the center of the gantry rotating unit 61 in the z-axis direction, or a pair of N and S pole rings may be disposed at both ends in the z-axis direction. You may. Alternatively, only one or two or more N-pole or S-pole rings may be arranged at intervals such that the magnetic flux density φz in the z-axis direction becomes non-uniform.

Returning to FIG. 3, a method (operation) for initially mounting the gantry rotating section 61 on the gantry fixing section 31 will be described. The gantry rotating section 61 is positioned and fixed to the gantry fixing section 31 by using an external support (a jack or the like) in a manner shown in the figure. At this time, the magnetic field Ha in the gap is maintained by the action of the permanent magnet 62 so as to maintain the superconductor 34 in a required mixed state.

In this state, for example, liquid nitrogen is filled into the container 32 of the fixing portion 31 by a cylinder (not shown) or the like, and the superconductor 34 is cooled to a predetermined temperature. As a result, as shown in FIG. 5, the superconductor 34 is gradually cooled, and then the superconductor 34 enters a mixed state. In this state, the magnetic fluxes φ ₁ , φ _2, etc. according to the external magnetic field Ha are pinned (stored) at the defective portion of the superconductor 34, and the levitation force of the magnitude corresponding to the temperature T and the magnetic field Ha and the z-axis direction A binding force is generated.

After a predetermined time has passed, when the bearing support of the gantry rotating section 61 by the gantry fixing section 31 is stabilized, the supply valve of the cylinder is stopped, and the liquid nitrogen in the container 32 is replenished by the cryostat 7 thereafter. Thereafter, even if the jack is removed, the gantry rotating section 61 is stably supported by the gantry bearing mechanism 5.

In the above embodiment, the case where the magnet 62 is provided on the gantry rotating section 61 and the superconductor 34 is provided on the gantry fixing section 31 is not limited to this. The superconductor 34 is provided on the gantry rotating part 61 side,
In addition, the magnet 62 may be provided on the gantry fixing portion 31 side. In this case, the cryostat 7 and necessary piping 7A are provided on the gantry rotating unit 61 side.

FIG. 8A shows an example (part) of mounting the superconductor 34 as an example. The container 32 in this case is entirely divided into cells (rectangular blocks) in a square lattice shape,
While maintaining the strength of the container 32 as a whole, a heat insulating material 33 (such as polytetrafluoroethylene) is coated on the entire inner wall of each cell to a required thickness. Holes 32b are provided between the cells so that the liquid nitrogen 35 can flow. Further, a columnar superconducting bulk 34 is fixed (adhesive or the like) in each cell, and the entire container 32 is sealed with a lid member 32 a similarly coated with a heat insulating material 33. The whole of such a container 32 is uniformly provided along the inner peripheral support surface of the gantry fixing portion 31, and is firmly fixed to the frame.

FIG. 8B shows another mounting example (part) of the superconductor 34. In this case, the entire container 32 is divided into regular hexagonal (honeycomb) cells, and the strength of the entire container 32 is further increased. Other structures may be the same as those described with reference to FIG.

FIGS. 9 to 11 are main part configuration diagrams (1) to (3) of a scanning gantry section according to another embodiment, in which the gantry bearing mechanism 5 is provided on the back side of the scanning gantry section 30. Is shown. Thereby, the shape of the scanning gantry unit 30 in a front view can be made compact.

FIG. 9 shows a magnet 62 on the gantry rotating section 61 side.
And a superconductor 34 is provided on the gantry fixing portion 31 side.
Is provided. The operation of the pin bearing is the same as that described for the configuration of FIG.

However, in this example, a magnetic layer 65 (iron, ferrite, etc.) is provided on the back side of the magnet 62, thereby improving the flow of the magnetic flux from the N pole to the S pole on the back of the magnet. . Thus, the magnetic flux density φz in FIGS. 7A and 7C can be increased (strengthened). This configuration can also be employed in the configuration of FIG. Although not shown, the rotary drive unit may use the linear motor system shown in FIG. 3 or a belt drive system as in the conventional example shown in FIG.

FIG. 10 shows a case where the superconductor 34 is provided on the gantry rotating part 61 side and the magnet 62 is buried on the gantry fixing part 31 side, contrary to FIG. The operation of the pin bearing is considered to be the same as that described for the configuration of FIG.

FIG. 11 shows a case in which the inner rotation supporting surface of the gantry rotating portion 61 is supported by the outer rotating supporting surface of the gantry fixing portion 31 inserted therein. The operation of the pin bearing is considered to be the same as that described for the configuration of FIG.

In each of the above embodiments, the medical X-ray C
Although the application example to the T device has been described, the invention is not limited to this. The present invention can be applied to an industrial X-ray CT apparatus as it is. Further, the present invention can be applied to a so-called MR apparatus (other computer tomography apparatuses in general) in which the subject is rotated and scanned in the same manner as the X-ray CT apparatus, although the principle of detecting the main signal is different.

Although the preferred embodiments of the present invention have been described, it goes without saying that various changes in the configuration, control, processing, and combinations thereof can be made without departing from the spirit of the present invention. There is no.

[0062]

As described above, according to the present invention, it is possible to rotate a rotating body made of a heavy object at a high speed and smoothly, which greatly contributes to the improvement of the function and performance of, for example, an X-ray CT apparatus. large.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a main part configuration diagram of an X-ray CT apparatus according to an embodiment.

FIG. 3 is a main configuration diagram (1) of a scanning gantry according to the embodiment;

FIG. 4 is a configuration diagram (2) of a main part of a scanning gantry unit according to the embodiment.

FIG. 5 is an explanatory diagram (1) of an operation of the gantry bearing mechanism according to the embodiment.

FIG. 6 is an operation explanatory view (2) of the gantry bearing mechanism according to the embodiment;

FIG. 7 is an explanatory view (3) of the operation of the gantry bearing mechanism according to the embodiment;

FIG. 8 is a diagram showing a mounting example of the superconductor according to the embodiment;

FIG. 9 is a configuration diagram (1) of a main part of a scanning gantry unit according to another embodiment.

FIG. 10 is a configuration diagram (2) of a main part of a scanning gantry according to another embodiment.

FIG. 11 is a configuration diagram (3) of a main part of a scanning gantry according to another embodiment.

FIG. 12 is a diagram illustrating a conventional technique.

[Explanation of symbols]

 Reference Signs List 5 Gantry bearing mechanism unit 6 Rotation drive unit 7 Cryostat 7A piping 10 Operation console 11 Central processing unit 11a CPU 11b Main memory (MM) 12 Input device 13 Display device (CRT) 14 Control interface 15 Data collection buffer 16 Secondary storage device 20 Imaging table 30 Scanning gantry section 31 Gantry fixing section 32 Container 33 Heat insulation layer 34 Superconductor 35 Coolant 36 Coil 40 X-ray tube 40A X-ray control section 50 Collimator 50A Collimator control section 61 Gantry rotation section 61A Rotation control section 62 Magnet 63 2 Next conductor plate 64 Nonmagnetic layer 65 Magnetic layer 70 X-ray detector array 80 Data acquisition unit (DAS)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Aihiko Eguchi 4-7, Asahigaoka, Hino-shi, Tokyo 127 G-Yokogawa Medical Systems Co., Ltd. F-term (reference) 3J102 AA01 BA04 BA17 CA04 DA03 DA07 DA09 DA22 DA27 GA01 GA20 4C093 AA22 BA03 BA10 CA27 CA39 EA02 EC41 EC60 4M113 AC44 CA31 4M114 AA28 AA29 AA31 BB03 BB04 CC04 CC18 DA03 DA18 DA51

Claims (8)

[Claims] 1. A rotating part and a fixed part supporting the rotation of the rotating part have their respective circumferential surfaces opposed to each other with a predetermined concentric gap therebetween, and a magnetic field generating part is provided on one of the circumferential surfaces. And a superconductor portion on the other circumferential surface, wherein the magnetic field present in the gap is configured to be uniform in the circumferential direction of the rotating portion and non-uniform in the axial direction. The bearing structure of the rotation mechanism. 2. The bearing structure for a rotation mechanism according to claim 1, wherein the magnetic field generator is made of a permanent magnet. 3. The magnetic field generating section includes an N pole and an S pole in the axial direction of the rotating section.
3. The bearing structure for a rotating mechanism according to claim 1, wherein the magnetic field of the poles is generated alternately. 4. The rotating mechanism unit according to claim 3, wherein the magnetic field generating unit includes a magnetic body for passing a magnetic flux from the N pole to the S pole on a surface opposite to the facing gap. Bearing structure. 5. The bearing structure according to claim 1, wherein the superconductor portion is made of a second-class superconductor. 6. The method for mounting a bearing structure according to claim 1, wherein the rotating portion is positioned on the fixed portion using an external support, and in this state, the magnetic field in the gap is maintained at a predetermined amount. After the superconductor is cooled to a predetermined temperature and the required magnetic flux pinning action in the superconductor is obtained, the external support is removed, and thereafter the rotating part is supported by the fixed part by the magnetic flux pinning action. A method for mounting a bearing structure, characterized in that: 7. A rotary unit for rotationally scanning / detecting a signal for obtaining a tomographic image of a subject, and a fixed unit for supporting the rotation of the rotary unit, each supporting a predetermined gap on a concentric circle. Are provided with a magnetic field generating portion on one of the circumferential surfaces, and a superconductor portion on the other circumferential surface, and the magnetic field present in the gap extends in the circumferential direction of the rotating portion. Uniform,
A computed tomography apparatus characterized in that it is configured to be non-uniform in the axial direction. 8. An X-ray detector array comprising: a rotating unit in which an X-ray tube and an X-ray detector array are opposed to each other with a subject interposed therebetween; and a fixed unit that supports rotation of the rotating unit. The computer tomography apparatus according to claim 7, wherein a CT tomographic image of the subject is reconstructed based on the CT.