Magnetic stimulation device

Abstract

Provided is a magnetic stimulation device that suppresses the heat generation of the conductor itself by taking steps to improve the structure of the conductor, thereby suppressing the temperature rise of the skin contact surface. The magnetic stimulation device (A) includes: a magnetic core (20) formed into a U-shape by a core body (21) and a pair of legs (22, 26) extending from the core body (21) in the same direction; and conductors (12, 16) composed of conductor layers (12a-12n, 16a-16n) wound around each of the legs (22, 26) and stacked in multiple stages. The cross-section of the wire used in each of the conductor layers (12a-12n, 16a-16n) parallel to the length direction of the legs (22, 26) is a quadrilateral, and is connected in parallel at each of the legs (22, 26). Between the legs (22, 26), the wires of the conductor layers (12a-12n) constituting one leg (22) are connected to the wires of the conductor layers (16a-16n) constituting the other leg 26 for each stage.

Description

Technical Field

[0001] The present invention relates to a device for improving the magnetic stimulation effect by using a coil having a magnetic core and a cooling mechanism when repeatedly magnetically stimulating peripheral nerves or a motor area of ​​the cerebral cortex. Background Art

[0002] Currently, there are 2 million patients with quadriplegia due to sequelae of cerebrovascular disease and spinal cord injury, and the number is expected to increase further as the age structure in Japan changes. If paralysis continues for a long time, muscle function will significantly decline due to disuse syndrome, and it will be difficult to recover. In order to prevent disuse syndrome caused by hemiplegia and quadriplegia and actively restore muscle function, rehabilitation based on exercise therapy is considered the most important treatment method.

[0003] Similarly, due to the change in the age structure in Japan, dysphagia caused by the sequelae of cerebrovascular disease and aging has become a social problem. Currently, most pneumonia, which is the third leading cause of death in Japan, is caused by aspiration pneumonia. As a rehabilitation method for dysphagia, rehabilitation based on exercise therapy that repeatedly activates muscles related to swallowing is the mainstream.

[0004] On the other hand, as a rehabilitation method not based on exercise therapy, it is known to electrically stimulate the peripheral nerves and the motor area of ​​the cerebral cortex to cause muscle movement. As an electrical stimulation method, transcutaneous electrical nerve stimulation TENS is widely used. Its principle is to electrically stimulate the motor nerves from the outside, thereby causing the contraction of the muscles of the hands and feet, so as to restore the motor function. Similarly, as a rehabilitation device for dysphagia, a medical device that applies electrical stimulation to the muscles under the jaw to cause the contraction of the swallowing-related muscles has been developed in recent years. In order to obtain large muscle contraction through electrical stimulation, strong electrical stimulation is required. Strong electrical stimulation is the same as electric shock, accompanied by strong discomfort and pain. In order to alleviate this discomfort and pain, various studies have been conducted to improve the frequency, waveform, etc., but it has not been fundamentally solved.

[0005] The pain associated with electrical stimulation is felt by pain nerves distributed near the surface of the skin. Therefore, by implanting the stimulation electrode under the skin, the pain of electrical stimulation can be alleviated. However, the implanted electrode requires the signal line to be exposed outside the body at all times, so there is a big problem of bacterial infection from the wound.

[0006] As another method of electromagnetically stimulating nerves without using contact electrodes, there is magnetic stimulation. This is a method in which a pulse current is passed through a coil placed near the body surface, and the induced current generated in the body by the magnetic flux generated by the coil is used to stimulate the nerves and activate the muscles. This magnetic stimulation method does not require the process of attaching or burying electrodes, and in addition, there is almost no discomfort or pain like electric shock.

[0007] For this reason, it has the advantage of being able to provide stronger stimulation and obtain greater muscle contraction than the electrical stimulation method. Therefore, magnetic stimulation has been applied to the diagnosis and treatment of diseases and has been put into practical use as transcranial magnetic stimulation (TMS). The combination of TMS with repeated magnetic stimulation and exercise therapy has a particularly large effect on rehabilitation (Non-Patent Documents 1 and 2).

[0008] Among the inventions that utilize the muscle contraction effect based on magnetic stimulation, there is a urinary incontinence treatment device disclosed in Patent Document 1. This device generates a pulsed magnetic field of 0.01 to 3 Tesla at 1 to 100 Hz from a magnetic stimulation coil fixed to a chair or the body, thereby repeatedly performing periodic contractions of the bladder sphincter, thereby treating urinary incontinence.

[0009] Patent document 2 shows a technology for continuously bending fingers or arms through magnetic stimulation instead of simple muscle contraction as in the treatment of urinary incontinence. It shows that when magnetic pulses are repeatedly applied at intervals of 10 milliseconds to magnetically stimulate the nerves in the arm, the bending distance of the arm increases as the number of pulses increases.

[0010] The effect of magnetic stimulation increases with the number of repetitions of magnetic stimulation. However, in order to induce magnetic stimulation, a large current of more than several hundred amperes needs to flow through the coil. Therefore, magnetic stimulation based on continuous pulses has the problem of heating of the coil and a sharp rise in temperature, which makes it impossible to increase the number of pulses. The heating of the coil becomes a major technical constraint for continuous magnetic stimulation.

[0011] In order to reduce the heating of the magnetic stimulation coil, it is effective to use a coil with a magnetic core (magnetic core) that obtains a strong magnetic field with a small current. Therefore, a patent application related to a magnetic stimulation coil with a magnetic core for transcranial magnetic stimulation has been proposed. Patent document 3 discloses a magnetic stimulation device that cuts off a part of the O-shaped magnetic core and makes the opposite part thinner and winds the coil therein to obtain a convergent magnetic field.

[0012] As an improved version of the above-mentioned Patent Document 2, Patent Document 4 discloses a magnetic stimulation device in which a magnet is arranged in a space formed inside the winding. In addition, Patent Document 5 describes a transcranial magnetic stimulation technology for performing magnetic stimulation of the brain by winding a coil from a semicircle with high magnetic permeability around a horseshoe-shaped magnetic core to reduce the heating of the coil. Patent Document 6 shows a technology using a strong magnet with high magnetic permeability and saturation magnetic flux density as a magnetic core of a similar shape.

[0013] Patent Document 7 describes a technique for reducing the heat generation of a coil by bundling thin Litz wires, which are conventional means of high-frequency coils, and winding the coils. However, regarding Litz wires, the cross-sectional area of ​​the insulating portion (including the gap portion between the coils) accounts for a high proportion of the cross-sectional area of ​​the conductive portion, which increases the resistance when the cross-sectional area of ​​the Litz wire itself is considered, and the coil portion is in a multi-layer heat-insulated state because the Litz wire insulated with a raw material having poor thermal conductivity is wound into multiple layers, and the heat from the portion wound inside is difficult to escape to the outside, so the temperature of the coil portion becomes above the allowable value.

[0014] Although there is such a problem of heat, since continuous magnetic stimulation can obtain a strong magnetic stimulation effect, it has the advantage of being able to induce large movements of the muscles of the fingers, hands and feet.

[0015] Therefore, the inventors adopted a method disclosed in Patent Document 8 as a method that cannot avoid heating of the coil.

[0016] Prior art literature

[0017] Non-patent literature

[0018] Non-patent document 1: Iyaya Publishing Co., Ltd. "Basics and Applications of Magnetic Stimulation Methods", Idee, Cerebrovascular Disorders, P.198 (Iyaya Publishing Co., Ltd. "Basics and Applications of Magnetic Stimulation Methods", Idee, Cerebrovascular Disorders, P.198)

[0019] Non-patent document 2: Chuo Hoki Publishing Co., Ltd., "Recovering the body and brain", Idee, Example of improving paralysis by magnetic stimulation, p. 183 (Chuo Hoki Publishing Co., Ltd., "Recovering the body and brain", Idee, Example of improving paralysis by magnetic stimulation, p. 183)

[0020] Patent Literature

[0021] Patent Document 1: Japanese Patent Application Laid-Open No. 10-234870

[0022] Patent Document 2: Japanese Patent Application Publication No. 2010-166971

[0023] Patent Document 3: Japanese Patent Application Laid-Open No. 7-171220

[0024] Patent Document 4: Japanese Patent Application Laid-Open No. 8-52231

[0025] Patent Document 5: Japanese Patent Publication No. 2000-504966

[0026] Patent Document 6: Japanese Patent Application No. 2001-525947

[0027] Patent Document 7: Japanese Patent Application Publication No. 2002-306614

[0028] Patent Document 8: Japanese Patent Application Publication No. 2016-28640 Summary of the invention

[0029] Patent Document 8 discloses a method of suppressing the temperature rise of the skin contact surface of the housing by air cooling the conductor itself, which functions as the magnetic core and the coil, and between the magnetic core and the skin contact surface of the housing. Fig.10 As shown, the conductors 120 and 160 formed of a wide material (an example of a copper strip material: a cross-sectional shape of 0.8×9 mm) are wound longitudinally (the length direction of the copper strip material is along the length direction of the legs 220 and 260) around the legs 220 and 260 of the U-shaped core 200. At this point in time, the cause of the heat generation of the conductors 120 and 160 when energized is unknown, so the temperature increase problem is solved by providing a cooling gap 300 to cool the conductors 120 and 160 and the legs 220 and 260 of the U-shaped core 200.

[0030] However, in this method, there are problems such as the need for the cooling gap between the conductors 120 and 160, in other words, the amount of the device and the cooling gap becomes larger accordingly; the overall area efficiency of the conductors 120 and 160 (the proportion of the conductive portion per unit cross-sectional area of ​​the conductor as a whole) decreases; and a cooling mechanism (for example, a cooling fan, a cooling gas supply duct) is required for supplying cooling gas to the casing, which becomes heavier according to the amount of the cooling fan or the convenience of use is reduced due to the presence of the duct.

[0031] The present invention is completed in view of the problems of the prior art, and its object is to provide a magnetic stimulation device that can suppress the temperature increase of the skin contact surface by taking steps to suppress the heat generation of the conductor itself through the structure of the conductor.

[0032] Technical solution 1 relates to the magnetic stimulation device A of the present invention ( Figure 1 to Figure 5 ) of the conductors 12 and 16 (multi-stage spiral structure; first embodiment), characterized by comprising: a magnetic core 20, which is formed by a core body 21 and a pair of legs 22 and 26 extending from the core body 21; and the conductors 12 and 16, which are composed of conductor layers 12a to 12n, 16a to 16n wound around each of the legs 22 and 26 and stacked in multiple stages,

[0033] The wires used in the conductor layers 12a to 12n and 16a to 16n have a quadrilateral cross section parallel to the length direction of the leg portions 22 and 26.

[0034] Between the pair of leg portions 22 and 26 , the wires of the conductor layers 12 a to 12 n constituting one leg portion 22 are connected to the wires of the conductor layers 16 a to 16 n constituting the other leg portion 26 for each stage.

[0035] Technical solution 2 relates to the magnetic stimulation device A (described in technical solution 1) Figure 4 ) is characterized in that:

[0036] Among the conductor layers 12a to 12n wound in multiple stages on one leg 22, the first layer 12a close to the front end 28 of the leg 22 is connected to the first layer 16a close to the front end 28 of the leg 26 among the conductor layers 16a to 16n wound in multiple stages on another leg 26, and the same layers from the second layer to the nth layer are connected to each other in sequence.

[0037] Technical solution 3 relates to the magnetic stimulation device A (described in technical solution 1) Figure 5 ) is characterized in that,

[0038] The first layer 12a of the conductor layers 12a to 12n wound in multiple stages on one leg portion 22 and located close to the front end 28 of the leg portion 22 is connected to the nth layer 16n of the core body 21 located closest to the leg portion 26 of the conductor layers 16a to 16n wound in multiple stages on the other leg portion 26.

[0039] The nth layer 12n of the core body 21 closest to the one leg portion 22 is connected to the first layer 16a wound in multiple stages on the other leg portion 26 close to the front end 28 of the leg portion 26.

[0040] The second layer 12 b to the (n−1)th layer 12 (n−1) of the one leg portion 22 and the (n−1)th layer 16 (n−1) to the second layer 16 b of the other leg portion 26 are connected in reverse order.

[0041] Technical solution 4 relates to the magnetic stimulation device A of the present invention ( Figure 1 to Figure 3 , Figure 6 , Figure 7 ) of the conductors 12 and 16 (multilayer coil spring-like structure: second embodiment), characterized in that it includes: a magnetic core 20 formed by a core body 21 and a pair of legs 22 and 26 extending from the core body 21; and the conductors 12 and 16 are composed of conductor layers 12a' to 12n' and 16a' to 16n' wound around each of the legs 22 and 26 so that the diameters thereof are different.

[0042] The cross section of the wire material used for the conductors 12 and 16 parallel to the length direction of the legs 22 and 26 is a quadrilateral.

[0043] Between the pair of legs 22 and 26 , the wires of the conductor layers 12 a ′ to 12 n ′ constituting one leg 22 are connected to the wires of the conductor layers 16 a ′ to 16 n ′ constituting the other leg 26 for each inner and outer layer.

[0044] Technical solution 5 relates to the first wiring method of the magnetic stimulation device A described in technical solution 4 ( Figure 6 ), characterized in that

[0045] The first layer 12a', which is the innermost layer close to the leg 22 among the conductor layers 12a' to 12n' wound in multiple layers on one leg 22, is connected to the first layer 16a', which is the innermost layer close to the leg 26 among the conductor layers 16a' to 16n' wound in multiple layers on the other leg 26, and the same layers from the second layer 12b', 16b' to the nth layer 12n', 16n' are connected to each other in sequence.

[0046] Technical solution 6 relates to a second wiring method of the magnetic stimulation device A described in technical solution 4 ( Figure 7 ), characterized in that

[0047] The innermost first layer 12a' close to the leg 22 among the conductor layers 12a' to 12n' wound in multiple layers on one leg 22 is connected to the outermost n-th layer 16n' of the core body 21 of the leg 26 among the conductor layers 16a' to 16n' wound in multiple layers on the other leg 26.

[0048] The nth layer 12n' of the outermost layer of the core body 21 of the one leg portion 22 is connected to the first layer 16a' of the innermost layer of the leg portion 26 wound in multiple layers.

[0049] The second layer 12 b ′ to the (n−1)th layer 12 ( n−1) ′ of the one leg portion 22 and the (n−1)th layer 16 ( n−1) ′ to the second layer 16 b ′ of the other leg portion 26 are connected in reverse order.

[0050] With regard to the magnetic stimulation device A of the present invention, the heat generation of the conductors 12 and 16 is suppressed by utilizing the above structure for reasons described below. As a result, when the device is used for treatment, the temperature of the affected part contact surface 9 of the housing 1 containing the magnetic core 20 can be maintained in a safe temperature range during the time required for treatment (e.g., 2 to 3 minutes or more), and thermal damage such as burns is not caused to the affected part.

[0051] In addition, as long as such a magnetic stimulation device A is used, the muscles that are difficult to move autonomously due to paralysis caused by brain dysfunction, etc. can be continuously and significantly moved through the action of a pulsed magnetic field. Even if the same muscle contraction effect can be achieved through electrical stimulation, electrical stimulation has the risk of (1) discomfort and pain similar to electric shock, (2) the time required to stick or bury electrodes, and (3) the risk of burns associated with electricity. However, magnetic stimulation does not have these problems (1) to (3). Even if limb paralysis occurs due to brain dysfunction, the nervous system and muscles are not damaged, so motor function can be restored by implementing appropriate rehabilitation treatment. However, if the state of being accompanied by impaired consciousness or being bedridden continues, motor function cannot be restored due to disuse syndrome. As long as the magnetic stimulation device A of the present invention is used for continuous magnetic stimulation, the muscles of paralyzed limbs and fingers can be effectively moved, so it is expected to improve the rehabilitation effect in an epoch-making way. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a three-dimensional diagram of the magnetic stimulation device of the present invention.

[0053] Figure 2 When the cover is removed Figure 1 Top view of the .

[0054] Figure 3 yes Figure 1 sectional view of .

[0055] Figure 4 It is shown Figure 3 A three-dimensional view of the main parts of the first wiring state in the first conductor structure.

[0056] Figure 5 It is shown Figure 3 A three-dimensional view of the main parts of the second wiring state in the first conductor structure.

[0057] Figure 6 It is shown Figure 3 A three-dimensional view of the main parts of the first wiring state in the second conductor structure.

[0058] Figure 7 It is shown Figure 3 A three-dimensional view of the main parts of the second wiring state in the second conductor structure.

[0059] Figure 8 It is shown Figure 4 A cross-sectional view showing the heating state of the conductor when current is applied thereto.

[0060] Fig. 9 It is shown Figures 5 to 7 A cross-sectional view showing the heating state of the conductor when current is applied thereto.

[0061] Fig.10 It is a cross-sectional view showing magnetic flux leakage in a conventional example.

[0062] Fig.11 It is a comparison graph of the heat generation state of the prior art example and the present invention.

[0063] (Explanation of symbols)

[0064] A: magnetic stimulation device; G: magnetic flux; U1, U2: eddy current; W: leakage flux; 1: outer shell; 2: outer shell body; 5: cover; 7: convex part; 9: affected part contact surface; 10, 14: excitation current supply line; 12, 16: conductor; 12a~12n, 16a~16n / 12a'~12n', 16a'~16n': conductor layer (first layer to nth layer); 17: part corresponding to the front end part of the core; 18: part corresponding to the part other than the front end part of the core; 20: magnetic core; 21: core body; 22, 26: foot; 28: front end of the foot; 120, 160: conductor; 200: U-shaped core; 220, 260: foot; 280: front end; 300: cooling gap. DETAILED DESCRIPTION

[0065] Next, according to the embodiment, the details of the present invention are described. In addition, this embodiment is an embodiment for facilitating the understanding of those skilled in the art. That is, it should be understood that the technical idea recorded only by the entirety of the specification of the present invention is limited, and is not limited to this embodiment.

[0066] The main components of the magnetic stimulation device A of the present invention are conductors 12 , 16 and a magnetic core 20 , which are housed in a housing 1 .

[0067] The magnetic core 20 is a U-shaped member in which legs 22 and 26 protrude in the same direction from both ends of the core body 21, and is formed by laminating a plurality of rolled silicon steel sheets with thin insulating films. As the magnetic core 20 of this embodiment, a magnetic core formed by laminating members punched into a U shape as described above, or a magnetic core formed by winding a rolled silicon steel strip into multiple layers and dividing it into two, etc. is used. The thickness of the rolled silicon steel sheet used in this embodiment is 0.35 mm.

[0068] In addition, in the present embodiment, the cross section of the leg portions 22 and 26 in the direction perpendicular to the longitudinal direction is a quadrilateral (square or rectangular) or a circle (not shown).

[0069] The conductors 12 and 16 are a collection of multi-stage conductor layers 12 a to 12 n and 16 a to 16 n wound around the leg portions 22 and 26 , or a collection of multi-layer conductor layers 12 a ′ to 12 n ′ and 16 a ′ to 16 n ′.

[0070] A member constituting the multi-stage conductor layers 12a to 12n, 16a to 16n or the multi-layer conductor layers 12a' to 12n', 16a' to 16n' is referred to as a wire.

[0071] In this wire, a long copper strip with a quadrilateral (square or rectangular) cross section is used as a raw material, and an insulating film is formed on its surface. An example is shown, in which the thickness of the wire is 0.9 mm and the height is 1.6 mm. The insulating film uses polyurethane resin and is thin enough not to hinder the heat dissipation on the surface of the conductors 12 and 16. In this embodiment, the thickness of the insulating film is set to 20 μm. (In addition, in the figure, due to the relationship of drawing, the cross section of the wire is sometimes shown as a circle, but as mentioned above, the cross section is a quadrilateral.)

[0072] The wires are wound around the legs 22 and 26 in such a manner that one side of the wire is wound several times along the outer circumference of one leg 22, and then the remaining portion is wound several times in the opposite direction around the other leg 26. In addition, an insulating film is formed on the surface of the wire, and as described later, the heat generation of the conductors 12 and 16 as a whole is small, so there is no need to provide a cooling gap 300 (see FIG. 1 ) required in the past between the wires. Fig.10 ), can be wound closely together. Therefore, the device can be made smaller in accordance with the amount of the cooling gap 300 required in the past.

[0073] In this case, the wire wound around the leg portions 22 and 26 is one wire as described above, but for convenience of explanation, conductors that are a collection of wires wound around the leg portions 22 and 26 are indicated as 12 and 16 , respectively.

[0074] As a winding method other than the above, although not shown in the figure, two wires may be prepared, and one side of one wire may be wound several times along the outer peripheral surface of one leg 22 as described above, and one side of the other wire may be wound several times along the outer peripheral surface of the other leg 26. Furthermore, each layer of the wires wound separately on the legs 22 and 26 may be connected with a connecting wire.

[0075] The housing 1 is a resin (ABS in this case) housing the magnetic core 20 and the conductors 12 and 16 wound around the legs 22 and 26 of the magnetic core 20. The housing 1 is formed by a housing body 2 having an upper surface opening and a cover 5 covering the opening, and is fixed by bolts (not shown) to close the upper surface opening.

[0076] A convex portion 7 bulging downward is formed on the lower surface of the housing body 2 that contacts the patient's affected part (ie, the affected part contact surface 9 ).

[0077] The front ends 28 of the leg portions 22 and 26 of the magnetic core 20 housed in the case 1 are fitted into the recessed portion inside the convex portion 7 of the cover portion 5 fitted to the case body 2 .

[0078] Furthermore, regarding the conductors 12 and 16 wound in multiple stages or multiple layers around the legs 22 and 26, the front ends 28 of the legs 22 and 26 are slightly protruded from the conductors 12 and 16 (the protrusion amount is 3 mm in this embodiment), and this portion is embedded in the recessed portion inside the convex portion 7 as described above. In addition, the front ends 28 of the legs 22 and 26 are held in a state of being in close contact with the recessed portion inside the convex portion 7 (or slightly separated therefrom), and the magnetic core 20 is fixed to the case body 2 by a fixing member not shown in the figure or by a method such as bonding.

[0079] In addition, there are two types of connection methods for the conductors 12 and 16 wound around the leg portions 22 and 26 in multiple stages or multiple layers, depending on the respective structures (first and second embodiments).

[0080] Figure 3 It is a cross-sectional view of the magnetic stimulation device A of the present invention and a partially enlarged view of the first or second structure (first and second embodiments) of the conductors 12 and 16. In addition, in the accompanying drawings, due to drawing reasons, the conductors 12 and 16 are described as being wound with gaps, but as mentioned above, they can be wound without gaps.

[0081] <First Embodiment>

[0082] according to Figure 4 , Figure 5 , a first embodiment of the conductors 12 , 16 is described.

[0083] like Figure 4 , Figure 5 As shown in FIG. 1 , the structure of the conductors 12 and 16 of the first embodiment is an example in which one wire is wound in multiple stages around the legs 22 and 26 of the magnetic core 20. That is, one wire is wound on planes that are perpendicular to the length direction of the legs 22 and 26 and are arranged in multiple stages. Furthermore, the planes are arranged in multiple stages between the front ends 28 of the legs 22 and 26 and the core body 21.

[0084] Therefore, the conductor layers 12a to 12n and 16a to 16n formed of one wire rod and wound around the leg portions 22 and 26 are provided in multiple stages over the first layer 12a and 16a to the n-th layer 12n and 16n.

[0085] Here, as a method of calculating layers, the layer close to the front end 28 of the leg parts 22 and 26 is set as the first layer 12a and 16a, the layer toward the core body 21 is set as the second layer 12b and 16b, and the layer closest to the core body 21 is set as the nth layer 12n and 16n.

[0086] Then, regarding the winding direction of the wire, according to the present invention as a whole, the wire is wound so that the direction S (N) of the magnetic field of the other leg 26 is opposite to the direction N (S) of the magnetic field of one leg 22 .

[0087] That is, in Figure 4 When the wires of the left conductor layer 12a··12n are wound counterclockwise, the wires of the right conductor layer 16a··16n are wound clockwise. Then, between the pair of legs 22 and 26, the corresponding ends of the wires of the left and right conductor layers 12a··12n and 16a··16n are connected to each other to form one wire.

[0088] Furthermore, regarding the wires constituting the conductor layers 12a to 12n and 16a to 16n wound around the legs 22 and 26, one end of each wire is connected in parallel for each leg 22 and 26 to form the conductors 12 and 16, and is connected to the excitation current supply lines 10 and 14 connected to the external power supply. In other words, the wires constituting the conductor layers 12a to 12n and 16a to 16n connected in parallel are connected to the excitation current supply lines 10 and 14 connected to the external power supply. Fig.10 The conventional longitudinally long strip conductors 120 and 160 are divided into a plurality of wires.

[0089] In addition, regarding the composition Figure 4 (described later Figure 5 The wires of each layer are also the same, showing an example of winding into a circular spiral, and can also be as Figure 2 and the following Figure 6 , Figure 7 As shown, the core 20 is wound into a quadrilateral spiral shape in a plan view that matches the cross-sectional shape of the leg portions 22 and 26 of the core 20 .

[0090] Then, between the pair of leg portions 22 and 26 , the wires of the conductor layers 12 a to 12 n constituting one leg portion 22 are connected to the wires of the conductor layers 16 a to 16 n constituting the other leg portion 26 for each stage.

[0091] Next, the case where power is supplied to the magnetic stimulation device A assembled as in the first embodiment will be described.

[0092] When an excitation current (pulse current or alternating current) is supplied from one excitation current supply line 10, the excitation current is divided and flows counterclockwise in the parallel conductor layers 12a to 12n wound around one leg 22, and then flows clockwise in the parallel conductor layers 16a to 16n wound around the other leg 26, and flows to the other excitation current supply line 14. As a result, the magnetic pole of the front end 28 of one leg 22 becomes S, and the magnetic pole of the front end 28 of the other leg 26 becomes N.

[0093] Then, when the excitation current in one direction stops flowing, the excitation current reverses and flows in the opposite direction from the other excitation current supply line 14, which is divided and flows in the clockwise direction in the parallel conductor layers 16a to 16n wound around the other leg 26, and then flows in the counterclockwise direction in the parallel conductor layers 12a to 12n wound around one leg 22, and flows to one excitation current supply line 10. As a result, the magnetic pole of the front end 28 of the other leg 26 becomes S, and the magnetic pole of the front end 28 of one leg 22 becomes N, and the magnetic pole is reversed. This action is repeated in a predetermined cycle. A magnetic flux G is generated between the two front ends 28 of the magnetic core 20.

[0094] Next, the effect of the magnetic stimulation device A of the present invention when it is powered on will be described. Fig.10 Explain the role of the previous example.

[0095] Fig.10 This is a conventional device developed by the inventors of the present invention. In this device, a U-shaped core 200 similar to the magnetic core 20 of the present invention is used, and conductors 120 and 160 are wound around a pair of leg portions 220 and 260 thereof.

[0096] The conductors 120 and 160 have a cross-section of an elongated rectangle, and are wound longitudinally so that the long sides are along the outer peripheral surface of the legs 220 and 260. The long sides of the conductors 120 and 160 are longitudinally long strips extending from the vicinity of the front ends of the legs 220 and 260 to the core body. The strip has a thickness of, for example, 0.8 mm and a height of 9 mm. A cooling gap 300 is provided between the conductors 120 and 160.

[0097] When an excitation current is supplied to the conductors 120 and 160 , as described above, the tip 280 of one leg 220 presents an N pole (S pole), and the tip 280 of the other leg 260 presents an opposite S pole (N pole).

[0098] Furthermore, it was not explained clearly at the time of developing the conventional device, but at that time, it was found that the inductance of the front end portion of the two leg portions 220, 260 of the U-shaped core 200 was partially lower than the inductance of the other portions, and as a result, the excitation current flowed concentratedly at the front end portion of the longitudinally long conductors 120, 160 facing the front end portion, and the present invention was achieved. In other words, it was found that the current density of the front end portion of the conductors 120, 160 arranged longitudinally long was higher than that of the other portions, and thus the temperature of the front end portion of the conductors 120, 160 increased abnormally.

[0099] In addition, the present invention was realized by newly discovering that leakage magnetic flux W from both leg portions 220 and 260 penetrates conductors 120 and 160 from the inner surface side to the outer surface side (or vice versa), and eddy current U1 flows in conductors 120 and 160 accompanied by Joule heat.

[0100] In the conventional device, the conductors 120 and 160 are provided in a long vertical direction, so a large eddy current U1 flows over the entire height of the conductors 120 and 160. It is found that this large eddy current U1 also causes the temperature of the conductors 120 and 160 to rise.

[0101] That is, it was found that since the conductors 120 and 160 are a single copper strip material having a wide width and arranged in a longitudinal direction, the temperature of the tip portion of the conductors 120 and 160 abnormally rises due to the synergistic effect of the above-mentioned imbalance in current density and the generation of a large eddy current U1. Therefore, in a conventional device without such knowledge, a cooling gap 300 and a cooling mechanism for supplying cooling gas to the cooling gap 300 are required.

[0102] In the present invention, based on such knowledge, as described above, the conductor layers 12a~12n, 16a~16n connected in parallel are arranged in multiple levels in the length direction of the legs 22, 26, which is the same structure as the structure in which the conventional longitudinally long conductors 120, 160 are divided into multiple wires. Therefore, the current density imbalance of each layer (especially the first layer 12a, 16a) is successfully eliminated to a large extent, and the eddy current U2 generated in each layer is reduced. As a result, the heating of the conductors 12, 16 is greatly suppressed.

[0103] The above point will be described in more detail. In the first embodiment, there are two methods for connecting the conductor layers 12a to 12n and 16a to 16n.

[0104] The first wiring method is as follows Figure 4 In the case where the conductor layers 12a to 12n and 16a to 16n are connected in the forward direction, the second wiring method is as follows Figure 5 The conductor layers 12a to 12n and 16a to 16n are connected in reverse order, which is opposite to the first wiring method.

[0105] In the first connection method, the first layer 12a of the conductor layers 12a to 12n wound around one leg 22 near the front end 28 of the leg 22 is connected to the first layer 16a of the conductor layers 16a to 16n wound around the other leg 26 near the front end 28 of the leg 26, and the nth layer 12n of the one leg 22 closest to the core body 21 is connected to the nth layer 16n of the leg 26 wound around the other leg 26 closest to the core body 21. Similarly, the second layer 12b to the (n-1)th layer 12(n-1) of the one leg 22 and the second layer 16b to the (n-1)th layer 16(n-1) of the other leg 26 are connected in sequence.

[0106] In contrast, in the second wiring method, the first layer 12a of the conductor layers 12a~12n wound on one leg 22 near the front end 28 of the leg 22 is connected to the nth layer 16n of the conductor layers 16a~16n wound on the other leg 26 closest to the core body 21, the nth layer 12n of the one leg 22 closest to the core body 21 is connected to the first layer 16a wound on the other leg 26 near the front end 28 of the leg 26, and the second layer 12b to the (n-1)th layer 12(n-1) of the one leg 22 and the (n-1)th layer to 16(n-1) to the second layer 16b of the other leg 26 are connected in reverse order.

[0107] In either case, when an excitation current is supplied to the conductors 12 and 16, the front end 28 of one leg 22 presents an N pole (S pole) alternately, and the front end 28 of the other leg 26 presents an opposite S pole (N pole), generating a magnetic flux G between the two poles.

[0108] In the first wiring method, when power is applied, as described above, the inductance of the tip portion of the leg portions 22 and 26 is smaller than that of other portions, and a slightly larger excitation current flows through the first layer 12a and 16a wound around the tip portion than through the other layers 12b and 16b, and the amount of excitation current in each layer decreases as it approaches the core body 21. However, unlike the conventional example, the conductors 12 and 16 are not formed of a vertically long single body, but are divided into a plurality of wires, so that the imbalance of current density is reduced.

[0109] Then, as described above, the leakage magnetic flux W emerges from the legs 22 and 26 of the magnetic core 20, and penetrates the conductor layers 12a to 12n, 16a to 16n in the same way as in the previous example. However, in this case, the conductor layers 12a to 12n, 16a to 16n are divided, so the height of the eddy current U2 caused by the leakage magnetic flux W is much lower than the longitudinal length of the previous example. Even if the eddy current U2 caused by the leakage magnetic flux W is generated, the eddy current generated on the short sides of each layer is small.

[0110] As a result, due to the greatly reduced current density imbalance and the slightly generated eddy current U2 on the short sides of each conductor layer 12a to 12n and 16a to 16n, the heat generation of the conductors 12 and 16 is greatly suppressed compared with the conventional example.

[0111] In addition, Figure 3 In FIG. 1 , the eddy current U2 is depicted outside the wire material of each layer, but this is recorded for the sake of easy understanding of the drawing, and is actually generated in the wire material.

[0112] exist Figure 8The temperature rise state of each conductor layer 12a to 12n, 16a to 16n in this case is schematically shown in . The temperature of each conductor layer 12a to 12n, 16a to 16n does not have a large temperature difference, but the temperature increases toward the front end 28 of the leg portion 22, 26.

[0113] Next, the second wiring method ( Figure 5 ). When an excitation current flows through the conductors 12 and 16, the excitation current flows slightly more heavily to the first layer 12a and 16a due to the above-mentioned inductance, as described above, but the n-th layer 12n and 16n connected to the first layer 12a and 16a is less likely to flow with the excitation current than the first layer 12a and 16a, so the n-th layer 12n and 16n become a bottleneck and suppress the excitation current flowing through the first layer 12a and 16a. In other words, the excitation current flowing through the first layer 12a and 16a is the same as that flowing through the n-th layer 12n and 16n.

[0114] This relationship applies not only to the second layer 12b, 16b and the (n-1)th layer 12(n-1), 16(n-1), but also to layers connected in the reverse order, and a substantially uniformly suppressed excitation current flows through the conductors 12, 16 of each layer as a whole.

[0115] The results, compared to Figure 4 The first wiring method shown in FIG. 1 can further suppress heat generation. In addition, the heat generation caused by the leakage flux W is Figure 4 The same situation.

[0116] exist Fig. 9 The temperature rise state of each conductor layer 12a to 12n, 16a to 16n in this case is schematically shown in FIG. The temperature of each conductor layer 12a to 12n, 16a to 16n is compared with Figure 8 , are averaged overall.

[0117] Next, the second embodiment is described. The second embodiment is different from the first embodiment in that the wires constituting the conductors 12 and 16 are wound closely in multiple layers on the legs 22 and 26 in a coil spring shape with different diameters from large diameter to small diameter. That is, the small diameter portion of the conductors 12 and 16 is arranged inside the large diameter portion in a sleeve state. The innermost layer of the conductors 12 and 16 wound closely in multiple layers is set as the first layer 12a' and 16a', and the outermost layer is set as the second layer 12b' and 16b'. The outermost layer is set as the nth layer 12n' and 16n'.

[0118] The conductors 12 and 16 constituting the first layer 12a' and 16a' to the n-th layer 12n' and 16n' can suppress the temperature rise of the conductors 12 and 16 as in the first embodiment, and thus can be wound closely without leaving any gaps vertically and internally.

[0119] Moreover, similarly to the first embodiment, between the legs 22 and 26, the wires of the conductor layers 12a' to 12n' constituting one leg 22 are connected to the wires of the conductor layers 16a' to 16n' of the other leg 26. The winding direction of the wires and the connection between the legs 22 and 26 are set so that the direction of the magnetic field of the other leg 26 is opposite to the direction of the magnetic field of the one leg 22.

[0120] That is, if the winding direction of each conductor layer 12a'~12n' wound on one leg 22 is set to rotate clockwise, then the winding direction of each conductor layer 16a'~16n' wound on the other leg 26 becomes counterclockwise, and between the legs 22 and 26, the wires constituting the inner and outer conductor layers 12a'~12n', 16a'~16n' are connected in a manner consistent with the above-mentioned winding direction for each of the inner and outer layers.

[0121] Furthermore, the wires of the plurality of conductor layers 12 a ′ to 12 n ′ and 16 a ′ to 16 n ′ wound around the leg portions 22 and 26 are connected in parallel for each leg portion 22 and 26 .

[0122] When the conductors 12 and 16 are energized, the excitation current flows downward from the top of the legs 22 and 26 (or upward from the bottom) through the inner and outer conductor layers 12a' to 12n', 16a' to 16n'. At this time, as described above, even if the inductance of the tip portion of the legs 22 and 26 is smaller than that of other portions, the portion 18 of the conductor layers 12a' to 12n', 16a' to 16n' corresponding to the portion other than the tip portion of the legs 22 and 26 having large inductance becomes a bottleneck, and the amount of excitation current flowing through the conductors 12 and 16 follows the portion 18 corresponding to the portion other than the tip portion of the legs 22 and 26. In other words, the imbalance of current density is largely eliminated.

[0123] Therefore, in this case, the temperature rise state of the conductors 12 and 16 is as follows: Fig. 9 That way the overall low level is kept uniform to some extent.

[0124] In addition, Figure 3 Schematically showing a portion 17 corresponding to the tip end portion of the leg portions 22 and 26 and a portion 18 corresponding to the portion other than the tip end portion of the leg portions 22 and 26.

[0125] There are also two wiring methods in the second embodiment. The wiring methods are basically the same as those in the first embodiment. They are described below.

[0126] The first wiring method is as follows Figure 6As shown, the innermost first layers 12a' and 16a' are connected to each other between the legs 22 and 26, and the wires of the same layer are connected to each other in order from the second layer to the nth layer toward the outside.

[0127] The second wiring method is as follows Figure 7 As shown, the innermost first layer 12a' close to the leg 22 among the conductor layers 12a'~12n' wound in multiple layers on one leg 22 is connected to the nth layer 16n' of the outermost layer of the core body 21 of the leg 26 among the conductor layers 16a'~16n' wound in multiple layers on the other leg 26, the outermost nth layer 12n' of the core body 21 of the one leg 22 is connected to the innermost first layer 16a' of the leg 26 wound in multiple layers on the other leg 26, and the second layer 12b' to the (n-1)th layer 12(n-1)' of the one leg 22 and the (n-1)th layer 16(n-1)' to the second layer 16b' of the other leg 26 are connected in reverse order.

[0128] As described above, when power is applied, the inductance of the front end portion of the leg portions 22 and 26 is smaller than that of other portions, but the influence is more significant in the layer closer to the inner side of the front end portion in the radial direction. In other words, when the front end portion of the first layer 12a' and 16a' is compared with the front end portion of the outermost layer 12n' and 16n', the first layer 12a' and 16a' are more affected.

[0129] As a result, the exciting current flowing through the first layers 12a' and 16a' is slightly stronger than the exciting current flowing through the outermost layers 12n' and 16n'.

[0130] In the first wiring method, the same layers are connected to each other in a manner such that the first layer 12a' is connected to the first layer 16a', and the nth layer 12n' is connected to the nth layer 16n'. Therefore, the first layers 12a' (16a') as the innermost layers are affected by the above-mentioned inductance to a certain extent, and the above-mentioned influence on the nth layer 12n' (16n') as the outermost layer is not as great as that of the first layers 12a' (16a') as the innermost layers.

[0131] However, in this case, the legs 22 and 26 are wound from the tip end direction toward the core body 21 in any layer, so the portion 18 corresponding to other than the tip end portion of the legs 22 and 26 becomes a bottleneck, which largely cancels out the above-mentioned influence.

[0132] As a result, in the second embodiment, even if the first wiring method is adopted, the imbalance of current density is significantly reduced compared with the first wiring method of the first embodiment, and the temperature rise can be suppressed more effectively.

[0133] In the second connection method, the first layer 12a' (16a') of one (another) leg 22 and the nth layer 16n' (12n') of the other (one) leg 26 are connected in reverse order, so in the reverse order combination of the first layer 12a' (nth layer 16n'), the portion 18 corresponding to the legs 22 and 26 other than the tip portions of the nth layer 16n' (12n') where the influence of inductance is the smallest becomes a bottleneck. This relationship is the same in other combinations, and the second connection method of the second embodiment has less imbalance in current density than the first connection method, and can also better suppress temperature rise.

[0134] According to the above, even if there is a slight deviation in the temperature rise of the conductors 12 and 16 of the second embodiment, Fig. 9 As shown.

[0135] <Experimental example>

[0136] Fig.11 Yes Fig.10 The conventional example shown is a time-temperature rise curve diagram which is used as a comparative example and compares the first wiring method and the second wiring method of the first embodiment.

[0137] In the figure, the solid line represents the second wiring method of the first embodiment, the dotted line represents the first wiring method of the first embodiment, and the single-dot chain line represents a conventional example.

[0138] The thin line of each line is the temperature of the conductor layer located at the center of the core leg, and the thick line is the temperature of the conductor layer located at the front end of the core leg. The unit is ° C. As a current source, a pulse power supply with a capacitor capacitance of 120μF was used, and the output voltage was fixed at 420V for comparison. The experimental conditions are as follows.

[0139] (Comparative Example)

[0140] Wire cross section: 0.8×9mm, 1 wire is used

[0141] Power output voltage: 420V

[0142] Magnetic flux density (core center): 0.64T

[0143] Excitation current: 1100A

[0144] (First embodiment)

[0145] Wire cross section: 0.9×1.6mm, 5 wires are used

[0146] Power output voltage: 420V

[0147] Magnetic flux density (core center): 0.62T

[0148] Excitation current: 1100A

[0149] In the comparative example, after power is applied, the temperature of the conductor layer at the tip of the leg reaches 80° C. in 70 seconds, but in the first connection method of the first embodiment, it takes 130 seconds, and in the second connection method of the first embodiment, it takes 190 seconds.

[0150] As a result, the continuous magnetic treatment time in this device is greatly prolonged.

[0151] In addition, regarding the second embodiment, it is considered that the continuous magnetic treatment time can be significantly prolonged based on the above-mentioned theory.

Claims

1. A magnetic stimulation device, characterized in that: The invention comprises: a magnetic core formed of a core body and a pair of legs extending from the core body; and a conductor composed of conductor layers wound around each of the legs and stacked in multiple stages. The cross section of the wire used in each of the conductor layers parallel to the length direction of the leg portion is a quadrilateral. Between the pair of legs, the wires of the conductor layers constituting one leg are connected to the wires of the conductor layers constituting the other leg for each stage. The first layer of the conductor layers wound in multiple stages on one leg, which is close to the front end of the leg, is connected to the nth layer of the core body closest to the leg, which is wound in multiple stages on the other leg. The nth layer of the core body closest to the one leg is connected to the first layer wound in multiple stages on the other leg near the front end of the leg, The second to (n-1)th layers of the one leg are connected to the (n-1)th to the second layers of the other leg in reverse order, One end portions of the first to n-th layers of wires constituting the legs connected in reverse order are connected in parallel for each leg.

2. A magnetic stimulation device, characterized in that: The invention comprises: a magnetic core formed into a U-shape by a core body and a pair of legs extending in the same direction from the core body; and a conductor formed by a plurality of conductor layers wound around each of the legs so as to have different diameters. The cross section of the wire used for the conductor parallel to the length direction of the leg is a quadrilateral. Between the pair of legs, the wires of the conductor layers constituting one leg are connected to the wires of the conductor layers constituting the other leg for each of the inner and outer layers. The innermost first layer close to the leg among the conductor layers wound in multiple layers on one leg is connected to the outermost nth layer of the core body of the leg among the conductor layers wound in multiple layers on the other leg. The nth outermost layer of the core body of the one leg is connected to the first innermost layer of the leg of the other leg wound in multiple layers. The second to (n-1)th layers of the one leg are connected to the (n-1)th to the second layers of the other leg in reverse order, One end portions of the first to n-th layers of wires constituting the legs connected in reverse order are connected in parallel for each leg.

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