JP2002000595A - Permanent magnet type motor and CT device - Google Patents

Abstract

(57) [Summary] [Problem] Electromagnetic noise caused by current flowing through a stator winding is
Provided is a permanent magnet type motor which is not superimposed on a signal line connecting a rotation position detecting element and a control circuit. An electromagnetic wave shield is disposed between signal lines so that noise generated in a stator winding is not superimposed on the signal line, and the electromagnetic wave shield is fixed to a stator core. Nut 52, outer cylinder 53,
A permanent magnet type motor in which a printed circuit board 50 is fixed to 51 using an anchor bolt 56 composed of a bolt 54 and an interval tube 55.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a rotor constituted by incorporating a plurality of permanent magnets on an outer peripheral surface of a rotor body, and a rotation position detecting element for detecting a rotation position of a pole of the rotor. In a permanent magnet type motor, and a CT apparatus that reconstructs a tomographic image of the subject from data obtained by irradiating the subject with radiation such as X-rays, a driving system that rotates an imaging system of the CT apparatus is used. The present invention relates to a CT apparatus using a permanent magnet type motor.

[0002]

2. Description of the Related Art Conventionally, a permanent magnet type motor used in an X-ray CT apparatus will be described with reference to FIGS. FIG. 10 is a diagram for explaining an electric circuit of the permanent magnet type motor. A three-phase winding (U winding, V winding, W winding) 32 as a stator winding is provided with a DC power supply 43. The AC power obtained by converting the DC power from the inverter by the inverter (switching power supply main circuit) 44 described below is supplied.

Inverter (switching power supply main circuit) 4
Reference numeral 4 includes, for example, transistors T1 to T6 and freewheel diodes D1 to D6, and freewheel diodes D1 to D6 are connected between the emitters and collectors of the transistors T1 to T6, respectively.

The base of each of the transistors T1 to T6 has
Base signals obtained from the control circuit 42 are sequentially applied. Detection signals from, for example, three rotation position detecting elements 41 for detecting the rotation position of the permanent magnet 22 of the rotor 20 described later are input to the control circuit 42, and a base signal is obtained based on the detection signals. It has become.

FIG. 11 is a front view of a conventional permanent magnet motor, and FIG. 12 is an enlarged longitudinal sectional view of the permanent magnet motor of FIG. The permanent magnet type motor includes a rotor 20 including a rotor main body 21 and a permanent magnet 22, a stator 30 including a stator core 31 and a stator winding 32, and a Hall I, for example.
It comprises a rotation position detecting element 41 made of C and a control circuit 42.

The stator core 31 is formed by laminating a plurality of silicon steel plates having, for example, an annular shape and formed with a plurality of slots 31S for accommodating the three-phase stator windings 32. A plurality of slots 31S formed in the stator core 31 in the axial direction are respectively provided with a U-phase winding 32U, a V-phase winding 32V,
W-phase winding 32W is inserted and arranged.

On the other hand, the rotor 20 has a plurality of permanent magnets 22 on the outer peripheral surface of an annular rotor main body (rotor iron core) 21 made of a magnetic material. It is adhered and fixed so as to have an interval, and is rotatably supported by a fixed portion (not shown) such as a bearing bracket in a state where the inside of the stator 30, that is, the inner peripheral portion of the stator core 31 and a predetermined gap 30g are provided. .

Further, in a state where the outer periphery of the rotor 20 and the predetermined gap 30g are provided, a plurality of, for example, three discrete type (for example, having a connection terminal 41L) for detecting the position, that is, the electrical phase of the permanent magnet 22 is provided. The rotational position detecting elements 41 each formed of a Hall IC of a type that cannot be mounted on the surface are arranged at predetermined positions of a circuit pattern (not shown) formed on the printed circuit board 46, for example, by soldering.

In this case, the printed circuit board 46 is
6, is fixed by a printed circuit board attaching means comprising a nut 47 and an interval tube 48. Specifically, the stator core 3
1, a through-hole is formed in the lamination direction of the silicon steel sheet,
A spacing tube 48 is provided at the end face of the core where the through hole is formed.
The bolt 46 is sequentially inserted through the bolt insertion hole, the center hole of the interval tube 48, and the through hole in a state where the printed circuit board 50 having the bolt insertion hole (not shown) is in contact with the interval tube 48. A nut 47 is screwed into the tip of a bolt 46 protruding from the stator core 31 via a washer or the like (not shown).

In this manner, the printed circuit board 50 is fixed in parallel with the end face of the stator core 31 in the stacking direction. A connection terminal 41L of the rotational position detecting element 41 is soldered in advance to a circuit pattern formed on one end face of the printed board 50, and a control circuit 42 is attached to the circuit pattern formed on the other end face of the printed board 50. A connector 49 connected to the other end of the signal line 45 that is electrically connected to the signal line 45 is configured to be able to contact and separate.

In this case, three rotational position detecting elements 41
Are arranged facing each other with a predetermined gap at a position along the outer peripheral surface of the permanent magnet 22. A signal line 45 for transmitting a rotation position signal obtained by the rotation position detection element 41 to a control circuit 42 disposed outside includes a winding 32 and a stator core 31.
It is located near.

FIG. 1 shows a motor constructed as described above.
AC power is supplied by the zero inverter 44. Thus, in accordance with the rotation position of the permanent magnet 22, that is, the rotation position detection signal of the rotation position detection element 41, the inverter 44 supplies the stator windings 32 U, 32 V, and 32 W to each of the U, V, and W phases. When 120 degrees (electrical angle) are applied in a predetermined order for each of two phases, the rotor 20 is rotated by the magnetic attraction and repulsion generated thereby.

[0013]

In the conventional permanent magnet type motor described above, electromagnetic noise (radiation noise) due to the current flowing through the winding 32 gives noise to the rotational position signal flowing through the signal line 45. In addition, an accurate rotation position detection vibration signal cannot be obtained, and the rotation accuracy deteriorates. Further, when the noise is large, the operation sequence of the control circuit 42 malfunctions, and thereby a large current flows, or in the worst case, the motor stops.

Further, when the motor is used in one of medical equipment, for example, an X-ray CT apparatus, there is a problem that a malfunction of the medical equipment occurs due to noise and a malfunction of the motor, resulting in a medical accident. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. A first object of the present invention is to superimpose electromagnetic noise due to current flowing through a stator winding on a signal line connecting a rotational position detecting element and a control circuit. A second object is to provide a CT apparatus which can prevent a medical accident which may be caused by electromagnetic noise and a malfunction of the motor.

[0016]

According to an aspect of the present invention, there is provided a rotor body rotatably supported with respect to a fixed portion and an outer peripheral surface of the rotor body. A plurality of permanent magnets which are arranged so that N poles and S poles are alternately arranged to form a rotor; A stator core having a slot for accommodating a wire, a rotational position detecting element mounted on a plate-shaped body disposed on a part of the outer peripheral surface of the permanent magnet and detecting a rotational position of the permanent magnet; An electromagnetic wave shield fixed to a stator core and disposed between the stator winding and a signal line to which an external signal is input, and having the plate-shaped member fixed thereto. It is a permanent magnet type motor.

According to a second aspect of the present invention, there is provided a rotor body rotatably supported with respect to a fixed portion, and an N pole and an S pole on an outer peripheral surface of the rotor body. A plurality of permanent magnets which are arranged alternately to form a rotor, and slots which are arranged on the inner peripheral side of the rotor and have an annular cross section and accommodate a plurality of stator windings; A rotation position detecting element mounted on a plate-shaped body disposed on a part of the outer peripheral surface of the permanent magnet and detecting a rotation position of the permanent magnet, and fixed to the stator core. A permanent magnet type motor, comprising: an electromagnetic wave shield that is disposed between the stator winding and a signal line to which an external signal is input, and that fixes the plate-like body. is there.

According to the invention corresponding to claim 1 or 2,
The electromagnetic wave shield is attached to the stator core, the printed circuit board is fixed to the electromagnetic wave shield, and the rotational position detecting element is fixed to the printed circuit board, so that the phase relationship between the stator winding and the rotational position detecting element is accurate. , And the reliability of the rotational accuracy is improved, and the electromagnetic wave shield can be made with an extremely simple electromagnetic wave shield, so that the cost and the number of assembling steps can be minimized.

To achieve the above object, the invention according to claim 3 is configured as follows. That is, the signal line according to claim 1 or 2 is a permanent magnet type motor fixed to the electromagnetic wave shielding body by a stopper.

According to the third aspect of the present invention, by fixing the signal line to the electromagnetic wave shield with the stopper, the signal line can be securely fixed, and the reliability against the noise due to the electromagnetic wave is improved.

In order to achieve the above object, the invention corresponding to claim 4 is configured as follows. That is, the electromagnetic wave shield according to any one of claims 1 to 3 is a permanent magnet type motor made of a conductive material or a material obtained by combining a conductive material and a magnetic material.

According to the invention, electric noise can be prevented by forming the electromagnetic wave shielding body from a conductive material, and the electromagnetic wave shielding body is made of a material combining a conductive material and a magnetic material. , Electrical noise and magnetic noise can be prevented.

In order to achieve the above object, the invention corresponding to claim 5 is configured as follows. That is, the printed circuit board according to any one of claims 1 to 4 is a permanent magnet type motor constituted by a conductive metal substrate.

According to the fifth aspect of the present invention, when the printed circuit board is formed of a conductive metal substrate, the rotational position detection signal can be less affected by noise from the stator winding current.

In order to achieve the above object, the invention according to claim 6 is configured as follows. That is, a plurality of steel plates are laminated, the stator core is formed by laminating a plurality of steel plates and has a bolt insertion hole in a predetermined position in the direction of the lamination, and the outer shape is in the axial direction. A nut formed in a tapered shape along
An outer cylinder formed by laminating a plurality of steel plates and inserted into the bolt insertion hole, and a bolt inserted into the bolt insertion hole, penetrating the electromagnetic wave shield, and connected to the stator core, 6. The space cylinder according to claim 1, wherein an outer diameter of the outer cylinder is expanded as the bolt and the nut are screwed, and the outer cylinder expands in an outer peripheral direction. 4. A permanent magnet type motor according to claim 1.

According to the invention corresponding to claim 6, mounting and dismounting of the rotational position detecting element are simplified, maintenance is facilitated, and a counterboring process is performed on the mounting surface of the stator core. No tapping is required, and the processing cost is reduced.

[0027] In order to achieve the above object, an invention according to claim 7 is directed to a radiation source, radiation detecting means arranged to face the radiation source, and a radiation detecting means interposed between the radiation source and the radiation detecting means. A stage on which the subject is movably mounted, a rotating gantry holding the radiation source and the radiation detecting means with the subject interposed therebetween and rotatably supported around the stage, and driving the rotating gantry In a CT apparatus having a rotation driving unit and a scanning unit that scans the subject by moving the stage while rotating the rotation gantry, the rotation driving unit is rotatably supported with respect to a fixed part. A rotor main body, a plurality of permanent magnets which are arranged so that N poles and S poles are alternately arranged on an outer peripheral surface of the rotor main body to constitute a rotor, and are disposed on an outer peripheral side of the rotor. And the cross section is A stator core having an annular shape and a slot for accommodating a plurality of stator windings, and a rotational position of the permanent magnet mounted on a plate-like body provided on a part of an outer peripheral surface of the permanent magnet. And a rotation position detecting element for detecting an external signal is fixed to the stator core and disposed between the stator winding and a signal line to which an external signal is input.
An electromagnetic wave shielding body to which the plate-like body is fixed is a CT apparatus.

According to the invention corresponding to claim 7, by applying the permanent magnet type motor according to any one of claims 1 to 6 to a CT apparatus of medical equipment, electromagnetic waves can be obtained. Noise and malfunction of the motor due to malfunction of the motor can be prevented, and a medical accident can be avoided.

In order to achieve the above object, the invention according to claim 8 is characterized in that the stator core is formed by laminating a plurality of steel plates and has a bolt insertion hole at a predetermined position in the direction of the lamination. A nut whose outer shape is formed in a tapered shape along the axial direction, an outer cylinder formed by laminating a plurality of steel plates and inserted into the bolt insertion hole, and inserted into the bolt insertion hole A bolt that penetrates the electromagnetic wave shield and is connected to the stator core, and an interval cylinder that is expanded in the outer diameter direction by expanding the outer diameter of the outer cylinder as the bolt and the nut are screwed together. The permanent magnet type motor according to claim 7, comprising:

[0030]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view illustrating a first embodiment of a permanent magnet type motor according to the present invention. The difference from the above-described conventional example is that an electromagnetic wave shield body 51 is newly added, and the printed circuit board 50 of the conventional example is replaced with the stator core 3.
Bolt 46, nut 47, spacing tube 4 for fixing to 1
Instead of providing a printed circuit board mounting means consisting of
It is a configuration for fixing the electromagnetic wave shield body 51 to the stator core 31, and includes a nut 52, an outer cylinder 53, a bolt 54,
An anchor bolt 56 including a spacing tube 55 is provided.

The electromagnetic wave shield 51 is made of a conductive material or a material obtained by combining a conductive material and a magnetic material and has an L-shaped cross section.
2 and fixed to the stator core 31 with anchor bolts 56 described below.

As shown in FIG. 4A, the outer shape of the nut 52 is tapered along the axial direction. The outer cylinder 53 is formed by laminating a plurality of steel plates, is inserted into a bolt insertion hole 31a formed in the stator core 31, is inserted into the opening side of the bolt insertion hole 31a, and the bolt 54 is connected to the electromagnetic wave shielding body. The outer diameter of the outer cylinder 53 is expanded by pushing the nut 51 through the space tube 55 and the outer tube 53, and by screwing the nut 52 sequentially to the tip of the bolt 54. The configuration is such that a force for expanding the outer peripheral direction is applied to the peripheral surface.

On the upper surface of the electromagnetic wave shield 51, FIG.
One end of the printed circuit board 50, which is configured in the same manner as the conventional example, is fixed, and the connection terminal 41L of the rotational position detecting element 41 is soldered in advance to a circuit pattern formed on one end surface of the printed circuit board 50, A connector 49 connected to the other end of the signal line 45 electrically connected to the control circuit 42 is configured to be able to contact and separate from the circuit pattern formed on the other end surface of the printed board 46. Printed circuit board 50
Is composed of a conductive metal substrate.

According to the first embodiment described above, the printed circuit board 50 on which the rotational position detecting element 41 is mounted is made of a conductive metal substrate and is arranged with an arbitrary gap from the stator winding 32. The signal line 45 from the printed circuit board 50 is wired to the outside along the surface opposite to the stator winding 32 on the electromagnetic wave shield 51 via the electromagnetic wave shield 51. That is, the signal line 4
5 and the stator winding 32 are shielded by the electromagnetic wave shield 51, so that the signal for electrically connecting the rotation position detecting element 41 and the control circuit 42 without being affected by the electromagnetic noise due to the stator winding 32. Not superimposed on line 45. Further, the electromagnetic wave shield body 51 can realize both the mounting of the printed circuit board 50 and the shield with a simple shape.

In this case, since the electromagnetic wave shield 51 can be used for mounting and fixing the printed circuit board 50 to the stator core 31 with a simple shape, the noise can be reduced at a minimum cost.

The rotational position detecting element 41 detects the rotational position of the pole of the permanent magnet 22 and sequentially supplies current to the corresponding winding 32 through the control circuit 42 and the inverter 44. That is, by attaching the rotation position detecting element 41 to the stator core 31, the rotation position detecting element 41 and the winding 3
Since the phase relationship 2 is maintained accurately and the optimal energization timing is maintained, the rotational accuracy of the motor is stabilized.

When the electromagnetic wave shield 51 is made of a conductive material, electric noise can be prevented. When the electromagnetic wave shield 51 is made of a material combining a conductive material and a magnetic material, electric noise can be prevented. And magnetic noise can be prevented.

The printed board 50 is formed of a metal board made of, for example, aluminum or iron. The wiring pattern between the rotational position detecting element 41 and the connector 49 is wired on the surface opposite to the winding 32. At this time, the influence of noise from the winding current on the rotation position detection signal flowing in the wiring pattern between the rotation position detection element 41 and the connector 49 on the printed circuit board 50 can be further avoided. can do.

Further, as shown in FIG. 4 (b), the nut 52 and the outer cylinder 53 are arranged so as not to protrude from the end face of the stator core 31. Is attracted to the head side of the bolt 54, and the outer cylinder 53 is spread by the movement of the nut 52, and is fixed by applying pressure.

Further, as shown in FIG.
In addition, by providing irregularities in accordance with the thickness (or a multiple thereof) of the laminated electromagnetic steel sheets, it becomes difficult to separate.

Further, as shown in FIG. 4 (d), due to the mounting positional relationship between the mounting holes and the anchor bolts 56, there is no protrusion on one side of the stator, and no counterboring or the like is required on the mating side. Also, the mounting hole does not require tapping, and by tightening the anchor bolt 56, the outer cylinder 53 expands,
The laminated surface and the concave and convex portions provided on the outer cylinder 53 are engaged with each other, and both are fixed.

Also, it is easy to remove, loosen the tightening of the bolt 54 and the nut 52, and once push the outer cylinder 53 of the anchor bolt 56 to the back, the outer cylinder 53 spreads out, and the whole anchor bolt 56 is easily removed. The rotation position detecting element 41 can be freely attached and detached.

Thus, using the anchor bolt 56,
By fixing the electromagnetic wave shield body 51 to the axial end face of the stator core 31, there is no need for counterboring or tapping on the mounting surface of the stator core 31, and the processing cost is reduced only. As a result, the attachment / detachment of the rotational position detecting element 41 is simplified, and maintenance is facilitated.

In the first embodiment, the electromagnetic wave shield 5
Although an L-shaped section is used as 1, it is not limited to this and may be a flat plate.

FIG. 2 is a longitudinal sectional view for explaining a permanent magnet type motor according to a second embodiment of the present invention.
Is a plan view thereof. The difference from the first embodiment of FIG. 1 described above is that the electromagnetic wave shield body 51A having a flat plate shape is used without using the electromagnetic wave shield body 51 having an L-shaped cross section, and is substantially perpendicular to the end face of the electromagnetic wave shield body 51A. The printed circuit board 50A is fixed so that a circuit pattern (not shown) formed on the printed circuit board 50A is a surface mount type (connection terminal is a plate-shaped) rotational position detecting element 41A.
, And a signal line 45 for electrically connecting the rotational position detecting element 41A and the control circuit 42 is connected to the electromagnetic wave shielding member 51 by, for example, a horseshoe-shaped stopper 57 and a screw.
A fixed by A.

As described above, by simply fixing the signal line 45 to the electromagnetic wave shielding body 51A using the stopper 57, wiring processing can be easily performed, and the signal line 45 can be securely fixed to the electromagnetic wave shielding body 51A. Therefore, the reliability against noise is improved.

In this case, by configuring the printed circuit board 50A as a metal substrate made of aluminum or iron, the influence of noise from the winding current of the rotational position detection signal can be further avoided. When a motor having such a configuration is used in an X-ray CT apparatus as a medical device, malfunction of the medical device due to noise and malfunction of the motor can be prevented, and a medical accident can be avoided. The rotational position detecting element 41A is not limited to a plurality, and may be provided singly, and the printed board 50A may be divided as long as it is a plate-like body as a whole.

FIG. 5 is a longitudinal sectional view for explaining a third embodiment of the permanent magnet type motor according to the present invention. In the first and second embodiments described above, the permanent magnet type motor in which the rotor 20 is arranged on the inner peripheral side of the stator 30 is a so-called adduction type (inner rotor). This is configured as a so-called abduction type (outer rotor) permanent magnet type motor in which a rotor 20A is arranged on the outer peripheral surface of a child 30.

This will be specifically described below. Two bearings 61a, 61b are fixed in a fixed part, for example, in a bearing housing 60 fixed on the inner peripheral side of an annular stator core 31.
And a cup-shaped rotor body 63 formed integrally with the rotating shaft 62 rotatably supported by the rotor, and N-poles and S-poles are alternately arranged on the inner peripheral surface of the rotor body 63. And a plurality of slots (not shown) for accommodating a plurality of stator windings 32 which are arranged on the inner peripheral side of the rotor 20A and have a circular cross section and which constitute a plurality of phases. )
And a plurality of stator cores 30 that are disposed so as to face a part of the inner peripheral surface of the permanent magnet 64 and that detect the rotational position of the permanent magnet 64 and are mounted on one printed circuit board 50. Discrete type rotational position detecting element 41
And a control circuit (not shown) for inputting a rotation position detection signal detected by the rotation position detection element 41 via a signal line 45 to determine the order of energized phases of the stator winding 32, and a stator core 31. 4 is disposed at least between the signal line 45 and the stator winding 32 so that noise generated in the stator winding 31 is not superimposed on the signal line 45. This is a permanent magnet type motor including an electromagnetic wave shield 51 to which a printed circuit board 50 is fixed.

In this case, the same operation and effect as in the embodiment of FIG. 1 can be obtained.

FIG. 6 is a longitudinal sectional view for explaining a first embodiment of the CT apparatus according to the present invention, FIG. 7 is a perspective view showing a schematic configuration of the CT apparatus, and FIG. It is a perspective view which shows a structure of. In the main body of the CT apparatus 1, there is provided an imaging system 4 composed of, for example, an X-ray tube 2, which is a radiation source described below, and a radiation detecting means, for example, an X-ray detection device 3, which is disposed to face the X-ray tube 2. A bed 14 on which a subject 13 is placed on a top plate 12 and movably mounted between the X-ray tube 2 and the X-ray detector 3, and the X-ray tube 2 and the X-ray A rotating base 5 having the detection device 3 and rotating around the top 12, and scanning the subject 13 by moving the top 12 during rotation of the rotating base (rotating frame) 5 a. In the CT apparatus main body 1 having scanning means,
The motor 6 of the rotating means for driving the rotary gantry 5 uses any of the permanent magnet type motors of the above-described embodiments. In this example, the rotational position detecting element 41 is fixed in contact with a resolver 7 that rotates together with the rotary gantry 5a and in contact with a fixed frame 5b provided corresponding to the rotary gantry 5a. However, the motor configuration described above may be used as it is.

In the case of the CT apparatus main body 1 shown in FIGS. 6, 7 and 8, the rotor 20 of the motor 6 and the imaging system 4 are directly fixed. Is a direct drive system that rotates. Accordingly, the effect of the above-described permanent magnet type motor is also provided, and the reliability of the rotation operation of the motor 6 can be improved at a lower cost. That is,
For example, when the motor 6 is used as a medical device in the CT apparatus main body 1, malfunction of the medical device can be prevented due to noise and malfunction of the motor 6, and a medical accident can be avoided. In the case of a medical device, the reliability of the CT device 1 and the motor 6 is very important because it is related to human life. Although the configuration of FIG. 6 includes the excitation circuit 8, the R─D converter 9, the motor control device 10, and the image processing device 11, these and other external false electromagnetic waves are more reliably shielded. Therefore, the rotation position detecting element 41 is installed in a space surrounded by the rotating frame 5a and the fixed frame 5bS. Resolver 7
Accordingly, the electromagnetic wave from the motor 6 can be shielded.

As described above, in mounting the printed circuit board 50, routing the signal line 45, and taking measures against electromagnetic interference (EMC) from the windings 32, the electromagnetic shield 51
Can be used with a simple configuration, so that the cost and the number of assembling steps can be minimized.

Since the rotational position detecting element 41 is directly attached to the stator core 31 via the electromagnetic wave shield 51, the phase relationship between the winding 32 and the rotational position detecting element 41 is accurately maintained, and Accuracy reliability is improved. When the signal line 45 is fixed to the electromagnetic wave shield body 51 with the stopper 57, a measure against electromagnetic wave interference from the winding 32 can be taken. When the printed board 50 is made of a conductive material, the printed board 3
2 can easily take countermeasures against the electromagnetic wave interference with respect to the circuit pattern in 2, and the reliability is further improved. For example, when the motor 6 is used as a medical device in the CT apparatus body 1, malfunction of the medical device can be prevented due to noise and malfunction of the motor 6,
Medical accidents can be avoided. In the case of a medical device, the reliability of the CT device main body 1 and the motor 6 is very important because it affects human life.

FIG. 9 shows a second embodiment of the CT apparatus according to the present invention.
It is a perspective view showing a schematic structure of an embodiment. in this case,
The motor 6 is disposed below the CT device 1 and the belt 1
5 is a belt drive system in which the photographing system 4 rotates via
The printed circuit board 50 and the electromagnetic wave shield 51 are attached to each motor 6. In FIG. 9, the same operation and effect as those of the embodiment of FIGS. 6 to 8 can be obtained.

[0057]

According to the present invention described above, there is provided a permanent magnet type motor in which electromagnetic noise due to current flowing through a stator winding is not superimposed on a signal line connecting a rotational position detecting element and a control circuit. It is possible to provide a CT apparatus capable of preventing a medical accident that can be caused by electromagnetic noise and malfunction of a motor.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of a permanent magnet type motor according to the present invention.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the permanent magnet type motor of the present invention.

FIG. 3 is a plan view showing a part of FIG. 2;

FIG. 4 is a view for explaining the anchor bolt of FIGS. 1 and 2;

FIG. 5 is a longitudinal sectional view showing a third embodiment of the permanent magnet type motor according to the present invention.

FIG. 6 is a schematic longitudinal sectional view showing a first embodiment (a direct drive system) according to the CT apparatus of the present invention.

FIG. 7 is a schematic perspective view of the CT apparatus shown in FIG. 6;

FIG. 8 is a perspective view of the CT apparatus of FIG. 6;

FIG. 9 is a schematic perspective view showing a first embodiment (belt drive system) according to the CT apparatus of the present invention.

FIG. 10 is a diagram showing an electric circuit configuration according to a conventional and permanent magnet type motor of the present invention.

FIG. 11 is a front view of a conventional permanent magnet type motor.

FIG. 12 is a longitudinal sectional view of a conventional permanent magnet type motor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... CT apparatus main body, 2 ... X-ray tube, 3 ... X-ray detector, 4
… Photography system, 5… rotating frame, 6… motor 7 resolver, 8…
Excitation circuit of resolver, 9 RD converter, 10 motor control circuit, 11 image processing circuit, 12 top plate, 13
... subject (patient), 14 ... bed, 15 ... belt, 20 ...
Rotor, 21: rotor body, 22: permanent magnet, 30: stator, 31: stator core, 32: stator winding, 41, 4
1A: rotational position detecting element, 45: signal line, 50, 50A
... Printed circuit board, 51, 51A ... Electromagnetic wave shield, 5
2 ... nut, 53 ... outer cylinder, 54 ... bolt, 55 ... interval cylinder.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoya Sasaki 1385-1, Higashiyama, Shimoishi-kami, Otawara-shi, Tochigi Inside the Toshiba Nasu Factory Co., Ltd. -1 F-term in Toshiba Nasu Factory Co., Ltd. (reference) 4C093 AA21 CA06 CA35 CA38 EC42 FA55 5H019 BB01 BB05 BB15 BB20 BB23 CC03 DD07 EE14 FF03 5H621 AA04 GA01 JK08 JK10 JK14

Claims (8)

[Claims] A rotor body rotatably supported by a fixed portion; and an N-pole and an S-pole alternately arranged on an outer peripheral surface of the rotor body to form a rotor. A plurality of permanent magnets, a stator core disposed on the outer peripheral side of the rotor and having a slot having an annular cross section and accommodating a plurality of stator windings, and one of the outer peripheral surfaces of the permanent magnet. A rotation position detection element mounted on a plate-like body provided in the unit and detecting a rotation position of the permanent magnet; a signal fixed to the stator core and inputting the stator winding and an external signal A permanent magnet type motor comprising: an electromagnetic wave shield disposed between the wire and a wire, and having the plate-shaped body fixed thereto. 2. A rotor body rotatably supported with respect to a fixed portion, and an N pole and an S pole are alternately arranged on an outer peripheral surface of the rotor body to form a rotor. A plurality of permanent magnets, a stator core disposed on the inner peripheral side of the rotor, having a toroidal cross section, and having a slot for accommodating a plurality of stator windings, and an outer peripheral surface of the permanent magnet. A rotation position detection element mounted on a plate-like body provided at a part thereof and detecting a rotation position of the permanent magnet; an external signal fixed to the stator core and receiving the stator winding; A permanent magnet type motor comprising: an electromagnetic wave shield disposed between the signal line and the plate-shaped body. 3. The permanent magnet type motor according to claim 1, wherein the signal line is fixed to the electromagnetic wave shielding body with a stopper. 4. The permanent magnet according to claim 1, wherein the electromagnetic wave shield is made of a conductive material or a combination of a conductive material and a magnetic material. Magnet type motor. 5. The permanent magnet type motor according to claim 1, wherein the printed circuit board is formed of a conductive metal substrate. 6. A stator core formed by laminating a plurality of steel plates and having a bolt insertion hole at a predetermined position in the direction of the lamination, and an outer shape tapered along an axial direction. A nut, an outer cylinder formed by laminating a plurality of steel plates and being inserted into the bolt insertion hole, being inserted into the bolt insertion hole, penetrating the electromagnetic wave shield, and being connected to the stator core. 6. The bolt according to claim 1, wherein the outer cylinder has an outer diameter dimension that is expanded as the screw and the nut are screwed together, and the outer cylinder attempts to expand in the outer peripheral direction. A permanent magnet motor according to any one of the preceding claims. 7. A radiation source; radiation detection means arranged to face the radiation source; a stage for movably mounting a subject between the radiation source and the radiation detection means; A rotary gantry holding the radiation source and the radiation detecting means with a sample interposed therebetween and rotatably supported around the stage; a rotary driving means for driving the rotary gantry; and while rotating the rotary gantry, Scanning means for scanning the subject by moving a stage
In the apparatus, the rotation driving means is disposed so that a rotor body is rotatably supported with respect to a fixed portion, and an N pole and an S pole are alternately arranged on an outer peripheral surface of the rotor body. A plurality of permanent magnets, a stator core disposed on the outer peripheral side of the rotor, having a circular cross section, and having a slot for accommodating a plurality of stator windings, and an outer periphery of the permanent magnet. A rotation position detecting element mounted on a plate-shaped body provided on a part of the surface and detecting a rotation position of the permanent magnet; and a stator winding and an external signal which are fixed to the stator core and input to the stator core. And an electromagnetic wave shield body to which the plate-like body is fixed while being disposed between the signal line and the signal line.
apparatus. 8. A stator core formed by laminating a plurality of steel plates and having a bolt insertion hole at a predetermined position in a direction of the lamination, and an outer shape tapered along an axial direction. A nut, an outer cylinder formed by laminating a plurality of steel plates and being inserted into the bolt insertion hole, being inserted into the bolt insertion hole, penetrating the electromagnetic wave shield, and being connected to the stator core. 8. The permanent magnet according to claim 7, further comprising: a bolt that extends, and an outer cylinder that expands in an outer diameter direction by expanding an outer diameter of the outer cylinder as the bolt and the nut are screwed together. 9. Shaped motor.