JP5222658B2 - High voltage transformer and inverter type X-ray high voltage apparatus using the same - Google Patents

Description

  The present invention relates to a high voltage transformer that boosts an input voltage to a high voltage, and more particularly to a technique for reducing parasitic capacitance and miniaturizing a high voltage transformer used in an inverter type X-ray high voltage device.

  In the X-ray CT apparatus, the X-ray tube is moved by moving the table on which the subject is placed in the body axis direction at the same time that the scanner rotating unit equipped with the X-ray tube and the X-ray detector is continuously rotated. A spiral CT is used that spirals relative to the subject. In order to reduce the weight of the spiral CT mounted on the scanner rotating part, the inverter operating frequency of the inverter type X-ray high voltage device is increased to make the high voltage transformer small and light.

  With the helical CT, “a wide range of scanning is possible in a short time”, “continuous data in the body axis direction can be obtained, which enables the generation of 3D images”, and “X-ray detectors in multiple rows Since many tomographic images can be captured at once, it has been applied to cardiac imaging.

  In such an X-ray CT apparatus, in recent years, since further scanning speed is required, it is necessary to rotate the scanner rotating section at high speed.

  For this purpose, it is necessary to further reduce the weight of the scanner rotating part. When the scan time is shortened, the tube current flowing between the anode and cathode of the X-ray tube must be increased in order to irradiate the subject with the same dose of X-rays in a short time. For this reason, the current flowing through the high voltage transformer increases, the high voltage transformer becomes large in size and increases in weight, which becomes an obstacle to high-speed rotation of the scanner.

  Therefore, it is necessary to reduce the size and weight of the insulating oil-sealed high voltage generator in which the high voltage transformer is housed. For that purpose, it is necessary to further increase the operating frequency of the inverter of the inverter type X-ray high voltage device to reduce the size of the iron core of the high voltage transformer, thereby making the high voltage transformer smaller and lighter.

  However, if the operating frequency of the inverter is increased to the vicinity of the parasitic resonance frequency generated by the leakage inductance of the high-voltage transformer and the parasitic capacitance of the windings, abnormal voltage may be generated. Need to significantly reduce the parasitic capacitance of the windings of the high voltage transformer.

  Further, the current flowing through the parasitic capacitance of the winding becomes a reactive current, and the current flowing through the primary winding and the secondary winding increases by this reactive current. Since the reactive current increases as the tube current increases, the parasitic capacitance of the winding must be reduced from this point.

  As a technique for reducing the parasitic capacitance of the winding, Patent Document 1 discloses a technique in which a secondary winding is divided into multiple parts and these are connected in series.

  Further, when the scanner rotating unit is rotated at a high speed, the centrifugal force applied to the insulating oil-sealed high voltage generator mounted on the scanner rotating unit increases.

  For this reason, along with the speeding up of the scanner rotating part, the high-voltage transformer and electric parts in the insulating oil-sealed high-voltage generator must be secured to the centrifugal force. This increases the size and weight of the scanner, and increases the burden on the scanner rotating unit.

  Therefore, in order to suppress the increase in size and weight of the high-voltage generator as much as possible and increase the mechanical strength, the insulating oil resin is used instead of the insulating oil-sealed type that is advantageous for fixing the secondary winding of the high-voltage transformer. It is conceivable to use a mold.

  Regarding the reduction in size and weight of a high-voltage transformer, Patent Document 2 discloses an example in which a secondary winding is mounted on a printed circuit board. Patent Document 3 discloses a technique for molding a secondary winding with resin as an advantageous means for weight reduction.

JP 2001-85235 A Japanese Patent Laid-Open No. 9-131062 JP-A-7-106162

  As described above, in order to increase the scanning speed, the operating frequency of the inverter of the inverter type X-ray high voltage device is increased to make the high voltage transformer mounted on the scanner rotating unit small and light, and the The high voltage transformer must be constructed to withstand the centrifugal force of high-speed rotation of the scanner.

  In order to increase the operating frequency of the inverter, it is necessary to significantly reduce the parasitic capacitance of the secondary winding of the high-voltage transformer, but the secondary winding of the transformer disclosed in Patent Document 1 Is a layered secondary winding, usually called layer winding, in which one layer is wound along the axial direction of the core and two layers are wound on that one layer. To reduce the electrostatic capacity.

  In this method, the parasitic capacitance of the secondary winding for avoiding resonance between the 5 kHz carrier frequency of the DC-DC converter (DC-DC conversion) and the parasitic resonance frequency can be sufficiently reduced. However, the operating frequency of the inverter of the inverter type X-ray high voltage device needs to be increased to several tens of kHz or more. However, in the technique of Patent Document 1, the winding per one turn between the wires facing each other with the interlayer insulation interposed between the transformers. Since the electrostatic capacity cannot be reduced, the parasitic electrostatic capacity of the secondary winding corresponding to the operating frequency of the inverter cannot be significantly reduced.

  In addition, in order to reduce the size and weight of the high-voltage transformer, when the secondary winding of Patent Document 2 is mounted on a printed circuit board, the insulation withstand voltage is reduced in order to pattern the secondary winding conductor. Since it depends on the creepage distance, the creepage distance must be increased.

  Therefore, if the conductor diameter of the secondary winding is increased by increasing the tube current due to higher scanning speed, the printed circuit board pattern must be enlarged in the width direction because of the limited thickness direction, and the printed circuit pattern becomes larger. When the substrates are arranged side by side, the parasitic capacitance between the substrates also increases.

  In addition, depending on the resist technology on the surface of the printed circuit board, in general, the insulation performance of the pattern portion is almost equal to the increase in voltage, so the distance between the printed circuit boards to ensure the insulation distance. It is necessary to take measures such as releasing. For this reason, for those requiring a large number of turns, the mounting becomes complicated, and the apparatus may become large.

  Furthermore, if the secondary winding is molded in order to make the high voltage transformer have a structure that can withstand the centrifugal force due to the high-speed rotation of the scanner, it is difficult for the resin to enter the winding in the conventional layer winding. The high-voltage transformer used in the X-ray generator has a high-voltage and low-current secondary output, so a round single wire is used for the secondary winding of the high-voltage transformer, and multiple layers are used in the layer winding. -Since it is wound in multiple layers, there is almost no gap between the layers, making it difficult for resin to enter.

  The present invention has been made in view of the above problems, and reduces the parasitic capacitance of the secondary winding of the high-voltage transformer and increases the operating frequency of the inverter by molding the secondary winding. An object of the present invention is to provide a small and lightweight high voltage transformer and an inverter type X-ray high voltage apparatus using the same.

  The above purpose is to arrange a plurality of spiral multilayer windings divided into two blocks and arranged in parallel at predetermined intervals, and to connect these spiral multilayer windings in series to form a secondary winding Specifically, it is achieved as follows.

(1) primary and secondary windings wound around the iron core, high voltage transformer which steps up the AC voltage input to the pre-Symbol primary winding and outputs a high voltage alternating current from the secondary winding The secondary winding is formed in a spiral shape in the same direction as the winding direction of the first multilayer winding, and the first multilayer winding wound in multiple layers. A plurality of one set of spiral multi-layer windings molded by embedding a set of spiral multi-layer windings composed of a second multi-layer winding wound in a multilayer and embedded in a molded body made of a resin material, These mold spiral multilayer windings are arranged in parallel at predetermined intervals, and are connected in series.

  (2) An interval holding member for maintaining the predetermined interval is provided between the adjacent pair of mold spiral multilayer windings.

  (3) The molded body has a first molded body having a first groove for winding the first multilayer winding and a second groove for winding the second multilayer winding. And a molded body, and an insulator is provided between the first molded body and the second molded body.

  (4) The molded body is a disk-shaped molded body having an opening.

  (5) The primary winding and the secondary winding are wound around different legs of the iron core.

  (6) The iron core is preferably a U-shaped cut core divided into two.

  (7) The first multilayer winding is spirally wound in multiple layers from the outside to the inside, and the second multilayer winding is continuous in the same direction as the winding direction of the first multilayer winding. And it is characterized by being wound in multiple layers in a spiral shape from the inside to the outside.

  (8) The high voltage transformer of the above (1) to (7) is used as a high voltage transformer of an inverter type X-ray high voltage device. Specifically, it is as follows.

  1) DC power supply, inverter that converts DC power from this DC power supply into AC power, primary winding to which the output voltage of this inverter is input, and input voltage of this primary winding is boosted to In an inverter type X-ray high voltage apparatus comprising a high voltage transformer having a secondary winding for outputting a high voltage, and a rectifier circuit for rectifying the output voltage of the high voltage transformer to a DC voltage, the high voltage The secondary winding of the transformer is formed in a spiral shape in the same direction as the winding direction of the first multilayer winding, and the first multilayer winding wound in multiple layers. A plurality of one set of spiral multi-layer windings molded by embedding a set of spiral multi-layer windings composed of a second multi-layer winding wound in multiple layers in a molded body made of a resin material, and these The mold spiral multi-layer windings are arranged in parallel at predetermined intervals. In which al is connected in series.

  2) An interval holding member for maintaining the predetermined interval is provided between the adjacent pair of mold spiral multilayer windings.

  3) The molded body includes a first molded body having a first groove for winding the first multilayer winding and a second groove having a second groove for winding the second multilayer winding. And an insulator is provided between the first molded body and the second molded body.

  4) The molded body is a disk-shaped molded body having an opening.

  5) The primary winding and the secondary winding are wound around different legs of the iron core.

  6) The iron core is preferably a U-shaped cut core divided into two.

  7) The first multilayer winding is spirally wound in multiple layers from the outside to the inside, and the second multilayer winding is continuous in the same direction as the winding direction of the first multilayer winding. And wound in multiple layers in a spiral shape from the inside to the outside.

  Resin is injected into a spiral multi-layer winding divided into two blocks and molded, and a plurality of these spiral multi-layer windings are arranged in parallel and connected in series to form a secondary winding. Since the line is configured, the parasitic capacitance of the secondary winding of the high-voltage transformer is greatly reduced compared to the conventional case, and the reactive current flowing through the parasitic capacitance is also greatly reduced. This makes it possible to reduce the size and weight of the high voltage transformer and the inverter type X-ray high voltage apparatus using the same.

  In addition, by storing the high-voltage transformer molded with the secondary winding in a high-voltage tank filled with insulating oil together with a high-voltage rectifier circuit, high-voltage generation can be installed on the scanner rotating part of the X-ray CT apparatus. Since the apparatus is reduced in size and weight and the centrifugal force of the scanner rotating unit is reduced, the scanning speed can be further increased.

  Hereinafter, preferred embodiments of a high voltage transformer of the present invention and an inverter type X-ray high voltage apparatus using the same will be described in detail with reference to the accompanying drawings.

  Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment of the present invention, and the repetitive description thereof will be omitted.

  FIG. 1 is a configuration diagram of an inverter type X-ray high voltage apparatus using a high voltage transformer according to the present invention. This inverter type X-ray high-voltage device includes a DC power source 1, an inverter circuit (DC / AC converting means) 2 that converts the voltage of the DC power source 1 into an AC voltage of a predetermined frequency, and an AC voltage of the inverter circuit 2. And a high voltage rectifier circuit 4 that rectifies the voltage of the high voltage transformer 3 and converts it into a DC high voltage, and the anode of the DC high voltage is grounded. X-rays are generated by applying between the anode 5a and the cathode 5b of the X-ray tube 5. Among these, the high voltage transformer 3 and the high voltage rectifier circuit 4 constitute a high voltage generator 6.

  The inverter type X-ray high voltage device configured as described above detects a tube voltage applied between the anode 5a and the cathode 5b of the X-ray tube 5 and controls it to be a set tube voltage (not shown). Tube voltage feedback control means, and tube current feedback control means (not shown) that controls the tube current flowing between the anode 5a and the cathode 5b of the X-ray tube 5 to detect and set the tube current to the set tube current. The tube voltage and tube current are controlled to be set values.

  The DC power source 1 may be any DC power source such as a DC power source obtained by converting a commercial power source voltage (not shown) into a DC voltage, or a DC power source using a battery. The circuit form for converting the commercial power supply voltage into a DC voltage is also a form in which the commercial power supply voltage is full-wave rectified by a full-wave rectifier circuit, or the DC voltage obtained by the full-wave rectification is adjusted by a chopper circuit. It is not limited to the conversion form, such as a form or a form in which the full-wave rectifier circuit has a voltage variable function.

  The inverter circuit 2 receives the DC voltage output from the DC power source 1 and converts it into a high-frequency AC voltage, and the tube voltage output from the high voltage generator 6 and applied to the X-ray tube is a target value. The tube voltage is controlled so as to become the target value by an inverter control circuit (not shown) that controls so that

  FIG. 2 is an example of a circuit of the high voltage generator 6 configured using the high voltage transformer of the present invention. As shown in FIG. 2, the high-voltage transformer 3 of the present invention includes an iron core 7, a primary winding 8 and a secondary winding 9 wound around the iron core 7, and the secondary winding 9 Has a plurality of windings 9a, 9b, 9c,... 9n, and these windings are connected in series.

  The plurality of secondary windings 9 connected in series are connected to the AC input side of the high voltage rectifier circuit 4. The high-voltage rectifier circuit 4 is composed of a plurality of rectifier circuits 4a, 4b, 4c,... 4n connected in series, and the rectifier circuits include the plurality of secondary windings 9a, 9b, 9c. ... 9n output voltage is input and a DC high voltage is output.

  Next, an embodiment of the high voltage transformer of the present invention used for the inverter type X-ray high voltage apparatus configured as described above will be described in detail.

First Embodiment
FIG. 3 is a perspective view of the first embodiment of the high-voltage transformer 3 according to the present invention.

  The high voltage transformer 3 includes an iron core 7, a primary winding 8 wound around the iron core 7, a secondary winding 9 wound on the primary winding 8, and the primary winding. And a reel 10 for holding 8 in a circular shape.

  The iron core 7 is a U-shaped cut core that is cut in two, and the primary winding and the secondary winding are wound around one leg of the split core.

  In FIG. 3, the primary winding 8 is hidden under the secondary winding 9, but is not visible, but the lead wire 8a of the primary winding is connected to the output side of the inverter circuit 2, The next winding 9 is connected to the input side of the high voltage rectifier circuit 4.

  The secondary winding 9 is formed by spirally winding a multilayer wound resin with resin, and arranging the plurality of molded windings in parallel at predetermined intervals and connected to the high voltage rectifier circuit 4 .

  FIG. 4 is a schematic diagram of a winding wound in multiple layers in a spiral shape. As shown in FIG. 4 (a), the spiral multilayer winding 9a includes a first multilayer winding 9a1 spirally wound in multiple layers from the outside to the inside, and the first multilayer winding 9a1. It consists of a second multi-layer winding 9a2 wound in a multi-layer from the inside to the outside continuously in the same direction as the winding direction. The first spiral multilayer winding 9a1 and the second spiral multilayer winding 9a2 are composed of two blocks having a number m of layers wound in a spiral, as shown in FIG. They are arranged in parallel with an insulation distance, and end insulation is performed by the end insulator 9c.

  As shown in FIG. 5, a set of spiral multilayer windings 9a composed of two sets of multilayer windings of the first multilayer winding 9a1 and the second multilayer winding 9a2 is provided in the insulating molded body 11. A resin such as epoxy is injected into this and molded (hereinafter, a set of the spiral multi-layer winding 9a 'is referred to as a mold spiral multi-layer winding).

  FIG. 6 is a view showing the structure of the mold spiral multilayer winding 9a ′. As shown in FIG. 6 (a), the mold spiral multilayer winding 9a ′ includes a first multilayer winding holder (first molded body) 9d1 around which the first multilayer winding 9a1 is wound and held. A second multilayer winding holder (second molded body) 9d2 around which the second multilayer winding 9a2 is wound and held, and the first multilayer winding 9a1 and the second multilayer winding 9a1 And a winding insulator 9e for ensuring the insulation withstand voltage.

  As shown in FIG. 6 (b), the first multilayer winding holder 9d1 includes a spiral groove (first groove) 9e1 and a secondary winding conductor 9f shown in FIG. An opening 9g1 having a diameter larger than the diameter of the primary winding (including an insulator) for winding the ticket on the primary winding 8 is provided. In the first multilayer winding 9a1, the secondary winding conductor 9f is wound around the groove 9e1 of the first multilayer winding holder 9d1 from the outside to the inside of the groove 9e1.

  Here, a1 is the start of winding of the first multilayer winding 9a1, and b1 is the end of winding of the first multilayer winding 9a1.

  Similarly, as shown in FIG. 6 (c), the second multi-layer winding holder 9d2 includes a spiral groove (second groove) 9e2 and the secondary winding conductor 9f. And an opening 9f2 having a diameter larger than that of the primary winding (including an insulator) for winding on the wire 8. In the second multilayer winding 9a2, the secondary winding conductor 9f is wound around the groove 9e2 of the second multilayer winding holder 9d2 from the inside to the outside of the groove 9e2.

  Here, a2 is the start of winding of the second multilayer winding 9a2, and b2 is the end of winding of the second multilayer winding 9a2.

  A round or square copper wire is used for the secondary winding conductor 9f, but the area of the first and second multilayer windings facing each other is smaller in the round shape. In addition, the parasitic capacitance between the multilayer windings can be reduced.

  In this way, the first multi-layer winding 9a1, the second multi-layer winding 9a2 and the same secondary winding conductor 9f are used for the first multi-layer winding 9a1 and the second multi-layer winding 9a2 to form a set of spiral multi-layer winding 9a. Therefore, the winding end b1 of the first multilayer winding 9a1 and the winding start a2 of the second multilayer winding 9a2 are the same, and the winding start a1 of the first multilayer winding 9a1 and the second multilayer winding 9a2 B2 is pulled out and a terminal is provided on the lead wire. When a voltage is applied to this terminal, the potential difference between the first multilayer winding 9a1 and the second multilayer winding 9a2 is small inside the spiral winding, but the potential difference is outside the spiral winding. growing.

  Therefore, the end insulator 9c (see FIG. 4 (b)) is provided to take measures to ensure the insulation withstand voltage of the lead wires at the winding start a1 and winding end b2.

  As shown in FIG. 6 (d), the winding insulator 9e has the same diameter as the opening 9g1 of the first multilayer winding holder 9d1 and the opening 9g2 of the second multilayer winding holder 9d2. An opening 9g3 and a slit 9h for holding the secondary winding conductor 9f are provided for continuously winding the first multilayer winding 9a1 and the second multilayer winding 9a2.

  The first multilayer winding holder 9d1 having the first multilayer winding configured as described above, the winding insulator 9e, and the second multilayer winding holder 9d2 having the second multilayer winding. 6a are stacked and housed in the insulating molded body 11, and resin is injected into the insulating molded body 11 and molded to form a mold spiral multilayer winding 9a '. .

  The secondary winding 9 in FIG. 3 is configured by arranging the mold spiral multilayer winding 9a ′ in parallel at predetermined intervals and connecting these mold spiral multilayer windings 9a ′ in series. The predetermined interval is secured by placing an interval holding member (not shown) between the mold spiral multilayer windings. The spacing member (not shown) has an opening having the same diameter as the mold spiral multilayer winding made of an insulator.

  A high voltage transformer is assembled in the following procedure using a plurality of mold spiral multilayer windings configured as described above.

  (1) An adhesive for adhering a U-shaped cut core cut in two is applied, and a fastening band for fixing the cut core is attached to the cut core. However, keep the tightening band open.

  (2) The winding frame 10 around which the primary winding is wound is attached to one leg portion of the U-shaped cut core cut in two.

  (3) Insulation treatment is performed on the primary winding, and a plurality of mold spiral multilayer windings are mounted in parallel on the primary winding with an interval holder interposed therebetween.

(4) Tighten the fastening band and adhere and fix the U-shaped cut core cut in two.

  (5) The primary winding and the secondary winding are fixed to the cut core, and terminals are attached to the lead wires of the primary winding and the secondary winding.

  FIG. 7 is a cross-sectional view of the primary winding 8 and the secondary winding 9 of the high-voltage transformer in the first embodiment assembled as described above. As shown in the figure, a primary winding 8 is wound on a winding frame 10, and an insulating treatment is applied on the primary winding, and a plurality of mold spiral multilayers are sandwiched therebetween with a spacing member interposed therebetween. You can see that the windings are arranged in parallel.

  The high-voltage transformer 3 configured in this way has its secondary winding connected to the high-voltage rectifier circuit 4, and is housed in a high-voltage tank (not shown) together with the high-voltage rectifier circuit 4 and immersed in insulating oil. The

  Next, the parasitic capacitance between the secondary windings of the high voltage transformer in the first embodiment (hereinafter referred to as winding capacitance) will be described.

  FIG. 8 is a diagram schematically showing a multilayer structure of the secondary winding of the high-voltage transformer in the first embodiment of the present invention.

In FIG. 8, the secondary winding 9 is a multi-layered coil spiral multilayer winding 9a 'composed of two blocks of the number m of layers wound in a spiral shape, that is, a multilayer having a divided block number b = 2n rows. It becomes winding, the equivalent winding capacitance C _T of the entire multi-layer winding, with reference to (5) of JP-a-2001-85235 of Patent Document 1,
C _T = c ₁ (k'-1) / (k ' ² mb) + c ₂ (m-1) k' / (bm ² )
+ c ₃ (m-1) ² (b-1) / (mb ² ) (Formula 1)
It becomes. here,
c ₁ ; Capacitance per turn between adjacent wires in the same layer
c ₂ ; Capacitance per turn between wires facing each other with interlayer insulation
c ₃ ; Capacitance per turn between wires facing each other with spacing between adjacent block windings when windings are divided into blocks
k '; the number of turns for one layer of each block winding part (the total number of turns for one layer is K)
It is.

In the winding method of the present invention, the number of windings for one layer in one block is 1, so k ′ = 1,
The number of blocks b is the same as the total number of turns K. Therefore, C _T is
C _T = c ₂ (m-1) / (Km ² ) + c ₃ (m-1) ² (K-1) / (mK ² ) (Formula 2)
It becomes.

Here, the conventional non-block division (one layer is wound in order from the top end to the bottom end along the axial direction of the iron core, and two layers are wound on the one layer from the top end to the bottom end. ) (1) of Patent Document 1 (Japanese Patent Laid-Open No. 2001-85235)
From the equation, the secondary winding capacity C _n by the multilayer structure is
C _n = c ₁ m (K-1) / (K ² m ² ) + c ₂ K (m-1) / m ² (Formula 3)
It becomes.

  Thus, the secondary winding capacity of the present invention can be calculated from (Equation 2), and the conventional secondary winding capacity can be calculated from (Equation 3).

  As an example, when the number of turns K = 200 for one layer of the number of divided blocks and the number of layers m = 10, the secondary winding capacity of the present invention is (Equation 4), and the conventional secondary winding The capacity is (Equation 5).

C _T = 4.5 × 10 ^-4 c ₂ + 0.04c ₃ (secondary winding capacity of the present invention) (Formula 4)
C _n = 5.0 × 10 ^-4 c ₁ + 18c ₂ (Conventional secondary winding capacity) (Formula 5)
When the distance between windings is almost the same, if c ₁ ≈c ₂ ≈c ₃
C _T ≈ 0.04c ₂ (Secondary winding capacity of the present invention) (Formula 6)
C _n ≒ 18c ₂ (Conventional secondary winding capacity) (Formula 7)
It becomes.

  As a result, the secondary winding capacity according to the present invention is reduced to about 450 times the conventional capacity. In (Equation 4), it is possible to further reduce the winding capacity by separating the mold spiral multilayer windings 9a ′ arranged in parallel by an appropriate distance.

  According to the first embodiment, the following effects can be obtained.

  (1) Resin is injected into a spiral multilayer winding divided into two blocks and molded, and a plurality of spiral multilayer windings are arranged in parallel to form a secondary winding. As a result, the distance between the multi-layer windings is shortened compared to the conventional case, and the secondary winding becomes smaller. Further, since the spiral multilayer winding is molded, the secondary winding can be easily assembled.

  (2) Since the parasitic capacitance between the secondary windings of the high-voltage transformer is greatly reduced compared to the conventional case, the current flowing through the parasitic capacitance between the secondary windings is also greatly reduced. The primary and secondary windings can use small-diameter wires, and the insulator can be small.

  (3) In addition, the parasitic resonance frequency generated by the leakage inductance of the high voltage transformer and the parasitic capacitance of the winding becomes very high due to the significant reduction of the parasitic capacitance between the secondary windings. Further, the operating frequency of the inverter circuit can be increased, and thereby the iron core can be reduced in size.

  (4) By winding the secondary winding around a small iron core, the high voltage transformer is downsized and the reactive current due to the capacitance of the winding is greatly reduced. The current is reduced and the inverter circuit is also downsized. As a result, the inverter type X-ray high voltage apparatus can be miniaturized.

  (5) By storing the high voltage transformer with the secondary winding in the high voltage tank together with the high voltage rectifier circuit, the high voltage generator mounted on the scanner rotating part of the X-ray CT system is smaller and lighter. As a result, the centrifugal force of the scanner is reduced, so that the scanning speed can be further increased.

<< Second Embodiment >>
FIG. 9 is a perspective view of a second embodiment of the high-voltage transformer 3 according to the present invention.

  This high voltage transformer 3 is configured such that the primary winding and the secondary winding of the first embodiment are wound around separate legs of a U-shaped cut core cut into two parts, and one leg The primary winding 8 is wound on the other side, and the secondary winding 9 is wound on the other leg portion.

  The primary winding 8 is wound around a winding frame 10 as in the first embodiment, and the secondary winding is a plurality of two blocks similar to those in the first embodiment on the winding frame 12. The molded spiral multilayer windings are arranged in parallel at predetermined intervals and connected to the high voltage rectifier 4.

  In the high voltage transformer 3 configured in this way, since the primary winding and the secondary winding are wound on separate legs of the U-shaped cut core, the insulating oil is immersed in the primary winding, The primary winding can be cooled more efficiently than in the first embodiment.

  In addition, since the circular diameter of the secondary winding wound in multiple layers in a spiral shape is smaller than that of the first embodiment by the amount of the circular diameter of the primary winding, the molded secondary winding The wire can be made small. As a result, the height of the high voltage transformer can be lowered, and the high voltage generator can be installed in a place where the height of the high voltage generator is limited.

  Furthermore, since the secondary winding capacity is reduced by reducing the circular diameter of the secondary winding, the current flowing through the inverter circuit is reduced, and the inverter circuit is also downsized.

<< Third Embodiment >>
FIG. 10 is a perspective view including a cross section of the third embodiment of the high-voltage transformer 3 according to the present invention. This high voltage transformer 3 is configured by winding the primary winding and the secondary winding of the first embodiment and the second embodiment around two legs of a U-shaped cut core cut into two parts. It is. That is, the primary windings 81 and 82, which are the same as the primary winding 8 of the first embodiment and the second embodiment, are wound around two legs and connected in parallel, and the first embodiment And the secondary winding 9 of the second embodiment is divided into two secondary windings 91 and 92, which are respectively wound around the primary windings 81 and 82 and connected in series. It is a voltage transformer.

  The primary windings 81 and 82 are wound around a winding frame (not shown) on two legs of a U-shaped cut core, respectively, and the secondary windings 91 and 92 divided into two are respectively the primary windings. A plurality of molded spiral multilayer windings composed of two blocks are arranged in parallel at predetermined intervals on the windings 81 and 82, and the secondary windings 91 and 92 arranged in this way are connected in series. Connected to the high voltage rectifier 4.

  The high-voltage transformer 3 configured in this way has the primary winding connected in parallel to ensure current capacity and at the same time reduce the leakage inductance seen from the primary winding side. Since the parasitic resonance frequency generated by the inductance and the parasitic capacitance of the winding becomes very high, the operating frequency of the inverter circuit can be further increased, and the high voltage transformer can be made small.

  As mentioned above, although the high voltage transformer by this invention and the inverter type | mold X-ray high voltage apparatus using the same were demonstrated using 1st-3rd embodiment, this invention is not limited to these embodiment. Rather, a plurality of spiral multilayer windings divided into two blocks and molded, which is the technical idea of the present invention, are arranged in parallel at predetermined intervals, and these spiral multilayer windings are connected in series. Any form may be used as long as it constitutes the secondary winding.

  For example, the following modifications are possible.

  (1) For spiral multilayer winding, a spiral groove was formed in the multilayer winding holder, and an electric wire was fitted into the groove to support it. For example, the multilayer winding was spiraled using a jig. The multilayer winding holder can be made unnecessary by maintaining the shape and injecting resin in this state and molding.

  (2) The mold spiral multilayer winding 9a ′ of FIG. 6 molds the first multilayer winding 9a1 and the second multilayer winding 9a2 respectively, and these molded first multilayer winding 9a1 ′ and A configuration including a winding insulator 9e for ensuring a dielectric strength voltage with respect to the second multilayer winding 9a2 ′ may be employed.

  (3) Although the winding insulator 9e is provided to ensure the insulation withstand voltage between the first multilayer winding 9a1 and the second multilayer winding 9a1, the mold is connected to the first multilayer winding 9a1 and the second multilayer winding 9a1. The first multilayer winding 9a1 and the second multilayer winding 9a1 are arranged in contact with each other so that the insulation withstand voltage of the second multilayer winding 9a1 can be secured, and the winding insulator 9e is unnecessary. It is also good.

  (4) A means for securing a predetermined interval by sandwiching an interval holding body between mold spiral multilayer windings was taken, but the mold was made to have a thickness of the predetermined interval, and the surfaces of the mold spiral multilayer windings were The interval holders may be made unnecessary by arranging in contact with each other.

  (5) The present invention is to divide the secondary winding into multiple parts and connect the multiple divided secondary windings in series in order to reduce the size and reduce the parasitic capacitance. As shown in FIG. 2, one rectifier circuit may be connected to one secondary winding, or a plurality of secondary windings connected in series are connected to one rectifier circuit. It may be configured.

  (6) The inverter type X-ray high-voltage device using the high-voltage transformer of the present invention is also applicable to an X-ray tube having a cathode grounded and an X-ray tube having a neutral point grounded with an X-ray tube housing grounded it can.

  (7) The first multilayer winding is spirally wound in multiple layers from the inside to the outside, and the second multilayer winding is continuously spiraled in the same direction as the winding direction of the first multilayer winding. Alternatively, it may be wound in multiple layers from the outside to the inside.

The block diagram of the inverter type | mold X-ray high voltage apparatus using the high voltage transformer by this invention. An example of the circuit of the high voltage generator comprised using the high voltage transformer of this invention. 1 is a perspective view of a first embodiment of a high voltage transformer according to the present invention. FIG. The schematic diagram of the secondary winding wound in multiple layers in a spiral. Schematic diagram of a set of spiral wound multi-layer windings. The figure which shows the structure of a mold spiral multilayer winding. The figure which shows the cross section of the primary winding and secondary winding of the high voltage transformer in the 1st Embodiment of this invention. The figure which shows typically the multilayered structure of the secondary winding of the high voltage transformer in the 1st Embodiment of this invention. The perspective view of 2nd Embodiment of the high voltage transformer by this invention. The perspective view containing the cross section of 3rd Embodiment of the high voltage transformer by this invention.

Explanation of symbols

1 DC power supply, 2 inverter circuit, 3 high voltage transformer, 4 high voltage rectifier, 5 anode grounded X-ray tube, 6 high voltage generator, 7 iron core of high voltage transformer, 8 primary of high voltage transformer Winding, 9 Secondary winding of high voltage transformer, 9a spiral multi-layer winding, 9a ′ mold spiral multilayer winding, 9a1 first spiral multilayer winding, 9a2 second spiral multilayer winding, 9d1 first molded body, 9d2 second adult form, 9e winding insulation, 9e1 first groove, 9e2 second groove, 9g1 first opening, 9g2 second opening, 9G3 third Openings, 11 compacts, b number of blocks, m number of layers, total number of turns for 1 layer

Claims (4)

In a high voltage transformer in which a primary winding and a secondary winding are wound around an iron core, and an alternating voltage input to the primary winding is boosted to output an alternating high voltage from the secondary winding.
The secondary winding is formed in a spiral shape and wound in multiple layers, and the secondary winding is formed in a spiral shape continuously in the same direction as the winding direction of the first multilayer winding. A plurality of one set of spiral multi-layer windings formed by embedding a set of spiral multi-layer windings formed of a resin material in a molded body made of a resin material;
These mold spiral multilayer windings are arranged in parallel at predetermined intervals, and these are connected in series ,
The molded body has a first molded body having a first groove for winding the first multilayer winding and a second molded body having a second groove for winding the second multilayer winding. With body,
A high voltage transformer , wherein an insulator having a slit in a radial direction of the multilayer winding is provided between the first molded body and the second molded body .   The high voltage transformer according to claim 1, wherein an interval holding member for maintaining the predetermined interval is provided between the adjacent pair of mold spiral multilayer windings. The shaped body is a high-voltage transformer according to claim 1 or 2, characterized in that the molding of disc shape having an opening. DC power source, inverter for converting DC power from the DC power source to AC power, a primary winding to which the output voltage of the inverter is input, and an input voltage of the primary winding is boosted to generate an AC high voltage In an inverter type X-ray high voltage apparatus comprising a high voltage transformer having a secondary winding that outputs a rectifier and a rectifier circuit that rectifies the output voltage of the high voltage transformer into a DC voltage,
The inverter type X-ray high-voltage apparatus, wherein the high-voltage transformer is the high-voltage transformer according to any one of claims 1 to 3 .

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