JP2022083519A - Injection device - Google Patents

Abstract

To provide an injection device which can efficiently accelerate an injection object.SOLUTION: An outer coil 11 has an annular shape with an object injection direction as a central axis, and into which current I1 flows clockwise. An inner short circuit coil 12 has an annular shape having an outer surface 12B and an inner surface 12C, and accelerates an object due to a magnetic field generated by flowing an induction current I2 guided to a magnetic field generated by the current I1 flowing into the outer coil 11, into the inner surface 12C. A clearance 12A is provided in the annular shape of the inner short circuit coil 12, and the outer surface 12B and the inner surface 12C are connected to each other by surfaces 12D and 12E separated by the clearance 12A. The induction current I2 flows from the outer surface 12B through a surface 12D into the inner surface 12C, flows clockwise into the inner surface 12C, and flows from the inner surface 12C through a surface 12E into the outer surface 12B.SELECTED DRAWING: Figure 8

Description

The present invention relates to an injection device.

At the International Space Station, activities are being carried out to release small satellites having various functions (Non-Patent Document 1). In this activity, a small artificial satellite will be transported from the ground to the experimental building "Kibo" installed at the International Space Station by a supply ship, and the small artificial satellite will be grasped by a robot arm and moved from the airlock to outer space. After that, a small artificial satellite is released into outer space by a spring mechanism provided on the robot arm.

However, in the spring mechanism, the injection speed of the object is limited, and as a method for overcoming such limitation, for example, the use of a coil gun (Non-Patent Documents 2 to 4) can be considered.

"JEM payload accommodation handbook -Vol.8- Ultra-small satellite emission interface management specification Rev.C", December 2017, Japan Aerospace Exploration Agency, December 5, 2018 search, URL: http: // iss. jaxa.jp/kiboexp/equipment/ef/jssod/images/jx-espc-110132-c.pdf Zou Bengu, et. Al., “Magnetic-Structural Coupling Analysis of Armature in Induction Coilgun”, January 2011, IEEE Transaction on Plasma Science, Volume 39, Issue 1, pp.65-70 Tao Zhang, et.al., “Design and Evaluation of the Driving Coil on Induction Coilgun”, May 2015, IEEE Transaction on Plasma Science, Volume 43, Issue 5, pp.1203-1207 Polzin, Kurt A., et.al., “Coilgun Acceleration Model Containing Multiple Interacting Coils”, January 2019, NASA Technical Reports, M18-7139

A coil gun accelerates an object made of a conductor by passing a time-varying electric current through a coil to generate a magnetic field. Therefore, it is desirable that the generated magnetic field is as strong as possible. However, since the current that can be passed through the coil is limited and the magnetic field generated by the coil is limited, it is difficult to efficiently accelerate the object by increasing the amount of current.

Further, as shown in Non-Patent Documents 2 to 4, it is possible to increase the speed of an object by arranging a plurality of coils in the injection direction of the object and accelerating the object in multiple stages. However, since the object passes at high speed in the coil located near the injection port, it is necessary to make the current rise as soon as possible. Therefore, the inductance of the coil has to be reduced, and as a result, the acceleration applied to the object is reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an injection device capable of efficiently accelerating an injection target.

Other issues and novel features will become apparent from the description and accompanying drawings herein.

The injection device according to the embodiment has an annular shape centered on the injection direction of the object, and has an outer coil through which a current flows in the first circumferential direction, an outer surface, and an inner surface surrounding the central axis. The inner short circuit coil has an annular shape, and has an inner short circuit coil in which an induced current generated by a magnetic field generated by the current flowing through the outer coil accelerates the object with a magnetic field generated by flowing the inner surface. A gap is provided on the circumference of the annular shape of the coil, and the outer surface and the inner surface of the inner short-circuit coil are connected by two ends of the annular shape separated by the gap to induce the induction. The current flows from the outer surface through one end to the inner surface, flows through the inner surface in a second circumferential direction, and flows from the inner surface through the other end to the outer surface. It is a thing.

According to the present invention, it is possible to provide an injection device capable of efficiently accelerating an injection target.

It is a figure which shows typically the structure of the injection system including the injection apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the example which an injection system is mounted on an artificial satellite. It is a figure which shows typically the basic structure of the injection apparatus which concerns on Embodiment 1. FIG. It is a figure which shows typically the acceleration of the object in the repulsion type coil gun. It is a figure which shows typically the acceleration of the object in the suction type coil gun. It is a figure which shows typically the acceleration of the object in the suction type coil gun. It is a perspective view of the coil which concerns on Embodiment 1. FIG. It is a front view when the coil which concerns on Embodiment 1 is seen from the + Z side. It is a figure which shows typically the YY cross-sectional structure of the coil which concerns on Embodiment 1. FIG. It is a perspective view of the coil which concerns on Embodiment 2. FIG. It is a front view when the coil which concerns on Embodiment 2 is seen from the + Z side. It is a figure which shows typically the YY cross-sectional structure of the coil which concerns on Embodiment 2. FIG. It is a figure which shows typically the YY cross-sectional structure of the coil which concerns on Embodiment 3. FIG. It is a perspective view of the coil which concerns on Embodiment 3. FIG. It is a front view when the coil which concerns on Embodiment 3 is seen from the + Z side. It is a figure which shows typically the YY cross-sectional structure of the coil which concerns on Embodiment 3. FIG. It is a figure which shows typically the XY cross-sectional structure of the coil which concerns on Embodiment 3. FIG.

Hereinafter, specific embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Further, in order to clarify the explanation, the following description and drawings have been simplified as appropriate. Further, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

Embodiment 1
The object injection device according to the first embodiment will be described. FIG. 1 schematically shows a configuration of an injection system 1000 including an injection device 100 according to the first embodiment. The injection system 1000 includes an injection device 100, a power supply device 110, and a control device 120.

The injection system 1000 supplies an electric current to an injection device 100 configured as a so-called coil gun, and accelerates and injects an injection object by the force generated at that time. The operating principle of the coil gun is described in, for example, Non-Patent Documents 2 to 4. The power supply device 110 is connected to the injection device 100 and is configured to be able to supply an electric current to the injection device 100.

The control device 120 is composed of, for example, a computer, and can control the operation of the power supply device 110 by giving a control signal CON. For example, the control device 120 can control the timing and waveform of the power supply device 110 supplying the current to the injection device 100, the current value of the current, and the like. Thereby, the control device 120 can control the timing at which the injection target is ejected from the injection device 100 and the injection speed of the injection target.

The injection system 1000 can be mounted on an artificial satellite, for example. FIG. 2 shows an example in which the injection system is mounted on an artificial satellite. In this example, as shown in FIG. 2, the injection system 1001 in which the shock absorbing device 140 is added to the injection system 1000 is mounted on the artificial satellite SAT. The power supply device 110 may be a power supply for the artificial satellite SAT. Further, the power supply device 110 may be coupled to the power supply system of the artificial satellite SAT and charged by a solar cell 130 or the like provided in the artificial satellite SAT. The control device 120 may be included in the control device of the artificial satellite SAT, or may be provided as a control device different from the control device of the artificial satellite SAT.

The shock absorbing device 140 is a device that cushions the impact when the object 1 is ejected from the ejection device 100. The shock absorber 140 may be a mechanism combined with a shock absorber or the like, or may be a device that injects gas in the direction opposite to the injection direction of the object 1.

The injection system 1001 can inject an object stored in the artificial satellite SAT into outer space. For example, a plurality of small artificial satellites can be stored in the artificial satellite SAT in advance, and the artificial satellite (object 1) can be launched in a predetermined direction at a predetermined speed as needed.

Next, the basic configuration and operation of the injection device 100 will be described. FIG. 3 schematically shows the basic configuration of the injection device 100 according to the first embodiment. In FIG. 3, the positive direction of the Z axis parallel to the horizontal direction of the paper surface (also referred to as the right direction of the paper surface, also referred to as the first direction) is defined as the ejection direction D of the object. Further, the vertical direction of the paper surface perpendicular to the Z direction is referred to as the Y direction (also referred to as a third direction), and the directions perpendicular to the Y direction and the Z direction are referred to as the X direction (also referred to as the second direction).

The object injection device 100 has a configuration in which a plurality of coils are arranged in the object injection direction D. In this example, the three coils 10 are arranged side by side at equal intervals of the pitch P with the injection direction D as the central axis. The accelerated body 2 is inserted into the acceleration space 3 that penetrates the hollow portions of the three coils 10 in the injection direction D. The accelerated body 2 is made of a magnetic member and functions as a striker for pushing out an object 1 which is an injection target.

Although not shown, the coil 10 may be installed inside a cylindrical member having the Z direction as a central axis, for example. The tubular member may have various shapes such as a circular shape, an elliptical shape, and a polygonal shape including a quadrangle as long as the coil 10 can be held. The end portion of the tubular member on the injection direction D side may be open or may be closed. Further, the cylindrical member may be provided with a hole or the like for weight reduction. Further, the coil 10 may be held by a member having an arbitrary shape other than the tubular member.

The accelerated body 2 made of a magnetic member is accelerated in the injection direction D according to the magnetic field generated when a current is passed through the coil 10. The injection device 100 is a suction type that accelerates the accelerated body 2 by an electromagnetic force acting on the accelerated body 2 when a current is passed through the coil 10 and ejects an object 1 held by the accelerated body 2. It is configured as a coil gun.

Next, the injection principle of the object in the coil gun will be described. It is generally known that the coil gun can be configured as a repulsive coil gun that ejects an object by a repulsive force due to an electromagnetic force, or a suction type coil gun that ejects an object by an attractive force due to an electromagnetic force.

The injection principle of the repulsive coil gun will be described. FIG. 4 schematically shows the acceleration of an object in a repulsive coil gun. As shown in FIG. 4, when a current (for example, pulse current) Ip is passed through the coil C in a state where the accelerated body 2 is located on the side of the injection direction D (Z direction) with respect to the coil C, the injection direction A magnetic field B is generated along D. FIG. 4 shows an example in which a current Ip flows counterclockwise through the coil when viewed from the + Z side. As a result, an eddy current EC flowing clockwise is generated on the bottom surface (the surface on the −Z side) of the accelerated body 2, and a repulsive force F due to the eddy current EC acts on the accelerated body 2 made of the conductor. The accelerated body 2 moves toward D in the injection direction. By the action of the repulsive force in this way, the object 1 attached to the accelerated body 2 is ejected in the ejection direction D.

Next, the injection principle of the suction type coil gun will be described. FIG. 5 schematically shows the acceleration of an object in a suction type coil gun. A current (for example, pulse current) Ip is applied to the coil C in a state where the accelerated body 2 is located on the side opposite to the injection direction D (+ Z direction) (the −Z side in FIG. 5, that is, the left side) with respect to the coil C. When the current is applied, a magnetic field B is generated along the injection direction D. As a result, as shown in FIG. 5, the magnetic force F acts on the accelerated body 2, and the accelerated body 2 made of the magnetic material is attracted toward the coil C to be accelerated. After that, as shown in FIG. 6, when the energization of the coil C is stopped when the accelerated body 2 reaches the coil C, the magnetic field B disappears, so that the magnetic force F acting on the accelerated body 2 also disappears. Therefore, as shown in FIG. 6, the object 1 attached to the accelerated body 2 continues to move in the injection direction D (Z direction) due to inertia and is ejected.

As described above, in the coil gun, since the object is accelerated by using the force generated by the electromagnetic force, it is desirable to make the generated magnetic field B as strong as possible in order to accelerate the object rapidly. Therefore, the coil according to the present embodiment has a configuration capable of strengthening the magnetic field generated by passing an electric current.

Hereinafter, the configuration of the coil 10 according to the present embodiment will be described. FIG. 7 is a perspective view of the coil 10 according to the first embodiment, FIG. 8 is a front view when the coil 10 according to the first embodiment is viewed from the + Z side, and FIG. 9 shows the coil 10 in the IX-IX line of FIG. The YY cross-sectional structure of the above is schematically shown. The coil 10 is composed of an outer coil 11 and an inner short-circuit coil 12.

The outer coil 11 is configured as a cylindrical coil having a closed ring shape with an injection direction (Z direction) as a central axis through which a current flows in one direction. In this example, the current I1 flows clockwise through the outer coil 11 when viewed from the + Z side. The outer coil 11 is preferably configured as a coil with a plurality of turns in order to strengthen the induced magnetic field generated by the flowing current I1.

The inner short-circuit coil 12 is configured as a one-turn cylindrical coil having a cross-sectional shape of an open ring centered on the injection direction (Z direction). In this example, the inner short-circuit coil 12 is provided with a gap 12A penetrating from the central axis to the outer periphery on the + X side of the inner short-circuit coil 12, and the inner short-circuit coil 12 is provided with an open ring shape, in other words, by this gap 12A. For example, the shape is similar to the letter C in the alphabet.

The outer coil 11 and the inner short-circuit coil 12 are arranged so as to be electrically isolated. That is, the outer coil 11 and the inner short-circuit coil 12 are spatially separated from each other. Further, an insulating material that insulates each other may be inserted and filled between the outer coil 11 and the inner short-circuit coil 12.

Next, the current flowing through the coil 10 and the induced magnetic field will be described. Assuming that the number of turns of the outer coil 11 is N (N is an integer of 2 or more) and the current supplied to the outer coil 11 is I, a clockwise current I1 = N × I flows through the outer coil 11 and the inner short-circuit coil is used. A current I2 flows counterclockwise in the direction opposite to the current I1 by electromagnetic induction on the outer surface 12B having a tubular shape. In this configuration, by making the outer coil 11 an N-turn coil, the inductance of the inner short-circuit coil 12 when viewed from the power supply side that supplies current to the outer coil 11 is ^doubled by N, and the energy supplied from the power supply side is supplied. It becomes possible to inject into the inner short-circuit coil 12 more efficiently.

The current I2 flowing through the outer surface 12B of the inner short-circuit coil 12 flows into the tubular inner surface 12C of the inner short-circuit coil 12 through the lower surface 12D (also referred to as the first end) of the gap 12A, and flows into the inner surface 12C. It flows clockwise through 12C. The current I2 then reaches the outer surface 12B of the inner short circuit coil 12 through the upper surface 12E (also referred to as the second end) of the gap 12A and flows counterclockwise through the outer surface 12B.

In this configuration, since the one-turn inner short-circuit coil 12 is inserted inside the multiple-turn outer coil 11, the induced magnetic field generated by the outer coil 11 is suitably coupled to the inner short-circuit coil 12. Therefore, the amount of the current I2 flowing through the inner short-circuit coil 12 can be increased by electromagnetic induction.

In order to efficiently accelerate the accelerated body 2, it is preferable that the induced magnetic field due to the current I1 flowing through the outer coil 11 is coupled to the inner short-circuit coil 12 as efficiently as possible. Therefore, it is preferable that the inner surface 11A of the outer coil 11 and the outer surface 12B of the inner short-circuit coil 12 are as close as possible. Further, as shown in FIG. 9, the dimension of the inner short-circuit coil 12 in the injection direction (Z direction) is preferably the same as or as close as possible to the dimension of the outer coil 11 in the injection direction (Z direction).

The current I2 flows so as to orbit the acceleration space 3 having a small diameter surrounded by the inner surface 12C of the inner short-circuit coil 12. Assuming that the inner diameter of the outer coil 11 is a and the inner diameter of the inner short-circuit coil 12 is b (that is, b <a), the strength of the magnetic field generated in the acceleration space 3 is (a) as compared with the case where the inner short-circuit coil 12 is not provided. / B) It is possible to ^double .

Therefore, according to this configuration, the accelerated body 2 can be efficiently accelerated by inducing a strong magnetic field in the acceleration space 3.

Embodiment 2
The injection device according to the second embodiment will be described. The injection device according to the second embodiment has a configuration in which the coil 10 of the injection device 100 according to the first embodiment is replaced with the coil 20.

Hereinafter, the coil 20 will be described. FIG. 10 is a perspective view of the coil 20 according to the second embodiment, FIG. 11 is a front view when the coil 20 according to the second embodiment is viewed from the + Z side, and FIG. 12 shows the coil 20 in the XII-XII line of FIG. The YY cross-sectional structure of the above is schematically shown. The coil 20 is composed of an outer coil 21 and an inner short-circuit coil 22.

Since the outer coil 21 is the same as the outer coil 11, the description thereof will be omitted.

The inner short-circuit coil 22 is configured as a one-turn cylindrical coil having a cross-sectional shape of an open ring centered on the injection direction (Z direction), similarly to the inner short-circuit coil 12 according to the first embodiment. To. In this example, the inner short-circuit coil 22 is provided with a gap 22A penetrating from the central axis to the outer circumference on the + X side of the inner short-circuit coil 22, and the gap 22A causes the inner short-circuit coil 22 to have an open ring shape. There is. Further, similarly to the inner short-circuit coil 12, the outer surface 22B and the inner surface 22C of the inner short-circuit coil 22 face each other with a gap 22A sandwiched between the surfaces 22D and 22E (that is, the first end and the second end). Are connected by.

Unlike the inner short-circuit coil 12, the inner short-circuit coil 22 is configured so that the dimension in the injection direction (Z direction) becomes smaller in the vicinity of the central axis. As shown in FIG. 12, the inner short-circuit coil 22 has a tapered shape in which the dimension in the injection direction (Z direction) continuously decreases from the outer surface 22B toward the inner surface 22C in the YZ cross section. There is. In this example, the dimension of the inner short-circuit coil 22 on the outer surface 22B in the injection direction (Z direction) is d, and the dimension of the inner short-circuit coil 22 on the inner surface 22C is c (c <d). ing.

As described above, according to the present configuration, by making the dimension in the injection direction (Z direction) of the central portion of the inner short-circuit coil 22 smaller than the dimension on the outer surface, the density of the current I2 flowing on the inner surface of the central portion is further increased. be able to. As a result, the strength of the electric field generated by the inner short-circuit coil 22 can be further increased, and the accelerated body 2 can be accelerated more efficiently.

Embodiment 3
The injection device according to the third embodiment will be described. The injection device according to the third embodiment has a configuration in which the coil 20 of the injection device according to the second embodiment is replaced with a coil 30.

Hereinafter, the coil 30 will be described. FIG. 13 schematically shows the YY cross-sectional configuration of the coil 30 according to the third embodiment. The coil 30 is composed of an outer coil 31 and an inner short-circuit coil 32.

Since the inner short-circuit coil 32 of the coil 30 is the same as the inner short-circuit coil 22 of the coil 20, the description thereof will be omitted. That is, the outer surface 32B and the inner surface 32C of the inner short-circuit coil 32 are connected by two facing surfaces (that is, a first end portion and a second end portion) with a gap in between.

The outer coil 31 of the coil 30 is configured by using the inner short-circuit coil 32 as a winding frame and winding an electric wire 31B coated with an insulating material, for example, a resin N times. In FIG. 13, the outer coil 31 is shown as a single-layer coil in which the electric wires 31B are wound so as to be aligned in the injection direction (Z direction), but may be configured as a multi-layer coil.

As described above, according to this configuration, since the outer coil 31 can be brought into close contact with the inner short-circuit coil 32, the induced magnetic field generated by the outer coil 31 can be more efficiently coupled to the inner short-circuit coil 32, and the outer coil 31 can be connected to the outer coil 31. Assuming that the flowing current is I3, the inner short-circuit coil 32 can induce a current of N × I3. Further, the outer coil 31 and the inner short-circuit coil 32 can be easily insulated by the covering material of the electric wire 31B constituting the outer coil 31.

Further, by inducing a strong magnetic field in the acceleration space 3, the accelerated body 2 can be efficiently accelerated, and an injection device that can be manufactured relatively easily can be realized.

Embodiment 4
The injection device according to the fourth embodiment will be described. The injection device according to the third embodiment has a configuration in which the coil 20 of the injection device according to the second embodiment is replaced with a coil 40.

Hereinafter, the coil 40 will be described. FIG. 14 is a perspective view of the inner short-circuit coil 42 of the coil 40 according to the fourth embodiment, FIG. 15 is a front view of the coil 40 according to the fourth embodiment as viewed from the + Z side, and FIG. 16 shows the XVI-of FIG. The YY cross-sectional structure of the coil 40 in the XVI line and the YY cross-sectional structure of the coil 40 in the XVII-XVII line of FIG. 15 are schematically shown in FIG. The coil 40 is a modification of the coil 20, and is composed of an outer coil 41 and an inner short-circuit coil 42.

Since the outer coil 41 is the same as the outer coil 21, the description thereof will be omitted.

Like the inner short-circuit coil 22, the inner short-circuit coil 42 is configured as a one-turn cylindrical coil having a cross-sectional shape of an open ring centered on the injection direction (Z direction). In this example, the inner short-circuit coil 42 is provided with a gap 42A penetrating from the central axis to the outer circumference on the X + side of the inner short-circuit coil 42, and the gap 42A causes the inner short-circuit coil 42 to have an open ring shape. There is.

However, unlike the inner short-circuit coil 22, the inner short-circuit coil 42 has an inner annular portion 421 that surrounds the acceleration space 3 and an outer annular portion 422 that surrounds the inner annular portion 421, and the inner annular portion 421 and the outer annular portion. There is a hollow portion 425 between the 422 and the hollow portion. Therefore, the outer surface of the outer annular portion 422 is the outer surface 42B of the inner short-circuit coil 42, and the inner surface of the inner annular portion 421 is the inner surface 42C of the inner short-circuit coil 42. The inner annular portion 421 (inner surface 42C) and the outer annular portion 422 (outer surface 42B) are connected by a bridge portion 423 provided on the lower side of the gap 42A and a bridge portion 424 provided on the upper side. ..

Next, the current flowing through the coil 40 and the induced magnetic field will be described. Assuming that the number of turns of the outer coil 41 is N (N is an integer of 2 or more) and the current supplied to the outer coil 41 is I, a clockwise current I1 = N × I flows through the outer coil 41, and the outer annular portion A current I2 flows through the 422 counterclockwise in the direction opposite to the current I1 due to electromagnetic induction. In this configuration, similarly to the outer coil 11 according to the first embodiment, the outer coil 41 is an N-turn coil, so that the inductance of the inner short-circuit coil 42 when viewed from the power supply side that supplies current to the outer coil 41. Is ^doubled by N, and the energy supplied from the power supply side can be injected into the inner short-circuit coil 42 more efficiently.

The current I2 flowing through the outer annular portion 422 of the inner short circuit coil 42 flows into the inner annular portion 421 through the lower surface 42D (ie, the first end) of the gap 42A and clockwise through the outer annular portion 422. It flows. The current I2 then reaches the outer annular portion 422 through the upper surface 42E (ie, the second end) of the gap 42A and flows counterclockwise through the outer annular portion 422.

As described above, according to this configuration, it is possible to pass a current in the same manner as the coil 20 according to the second embodiment. Further, by providing the hollow portion 425 in the inner short-circuit coil 42, the inner short-circuit coil 42 can be made lighter than the inner short-circuit coil 22.

Other Embodiments The present invention is not limited to the above embodiments, and can be appropriately modified without departing from the spirit. For example, in the above-described embodiment, the outer coil and the inner short-circuit coil have been described as having a cylindrical shape, but any cylindrical coil other than the cylindrical coil may be used as long as the object can be accelerated.

Although it has been described that the inner short-circuit coil has only one gap, two or more gaps are provided in the inner short-circuit coil as long as a current can flow in the same direction between the outer surface and the inner surface of the inner short-circuit coil. May be good.

In FIG. 3, an example in which three coils are arranged in the injection device has been described, but this is only an example. Only one coil may be arranged in the injection device, or two or four or more coils may be arranged.

In the injection device according to the first and fourth embodiments, the outer coil may have the same configuration as the outer coil 31 according to the third embodiment.

1 Object 2 Accelerated body 3 Acceleration space 10, 20, 30, 40 Coil 11, 21, 31, 41 Outer coil 11A Inner surface 12, 22, 32, 42 Inner short circuit coil 12A, 22A, 42A Gap 12B, 22B, 32B , 42B outer surface 12C, 22C, 32C, 42C inner surface 31B electric wire 12D, 12E, 22D, 22E, 42D, 42E surface 100 injection device 110 power supply device 120 control device 130 solar cell 140 shock absorber 421 inner ring part 422 outer ring Part 423, 424 Bridge part 425 Hollow part 1000 Injection system 1001 Injection system C coil CON control signal SAT artificial satellite

Claims (6)

An outer coil having an annular shape with the injection direction of the object as the central axis and a current flowing in the first circumferential direction around the central axis.
It has an annular shape having an outer surface facing the outer coil and an inner surface surrounding the central axis, and an induced current induced by a magnetic field generated by the current flowing through the outer coil flows through the inner surface. With an inner short-circuit coil, which accelerates the object by the resulting magnetic field,
A gap is provided on the circumference of the annular shape of the inner short-circuit coil, and the outer surface and the inner surface of the inner short-circuit coil are separated from the first end portion of the annular shape by the gap. Connected by the end of 2
The induced current flows from the outer surface through the first end to the inner surface, flows through the inner surface in a second circumferential direction opposite to the first circumferential direction, and from the inner surface. Flowing through the second end to the outer surface.
Injection device. The inner short-circuit coil has a C-shaped shape.
The injection device according to claim 1. The dimension in the direction of the central axis on the inner surface of the inner short-circuit coil is smaller than the dimension in the direction of the central axis on the outer surface.
The injection device according to claim 1 or 2. The dimension of the inner short-circuit coil in the direction of the central axis is continuously reduced from the outer surface toward the inner surface.
The injection device according to claim 3. The outer coil is configured by winding an electric wire coated with an insulating member around the outer circumference of the inner short-circuit coil.
The injection device according to any one of claims 1 to 4. The inner short-circuit coil is
The outer annular portion having the outer surface and the outer annular portion,
An inner annular portion having the inner surface and arranged on the side of the central axis with respect to the outer annular portion.
A first bridge portion connecting the outer surface and the inner surface, wherein the surface facing the gap is the first end portion.
A second bridge portion connecting the outer surface and the inner surface is provided with a surface facing the gap as the second end portion.
The injection device according to any one of claims 2 to 5.

Images