WO2015080049A1

WO2015080049A1 - Electrodynamic vibration generator

Info

Publication number: WO2015080049A1
Application number: PCT/JP2014/080912
Authority: WO
Inventors: 秀修青木; 中村　勝彦; 一志中西
Original assignee: Imv株式会社
Priority date: 2013-11-28
Filing date: 2014-11-21
Publication date: 2015-06-04
Also published as: JP2015105823A; JP5758475B2

Abstract

An electrodynamic vibration generator is provided that has a single-yoke magnetic circuit structure but is capable of reducing leakage flux to the level of that of a double-yoke magnetic circuit structure. This electrodynamic vibration generator is provided with an excitation coil (2) for generating a static magnetic field, a yoke (1) comprising a ferromagnetic body for forming a magnetic circuit using the static magnetic field generated by the excitation coil (2) and forming a magnetic gap (4), a drive coil (5) for vibration generation that is disposed in the magnetic gap (4), and a vibration table (6) that is integrally formed with the drive coil (5). A degaussing coil (3) for generating a canceling magnetic flux (ϕ_c2) for canceling the leakage flux (ϕ_L1) of the magnetic flux of the static magnetic field generated by the excitation coil (2) is disposed inside the yoke (1) near the vibration table (6). The yoke (1) has, to the side of the magnetic gap (4) opposite from the vibration table (6), an excitation coil accommodation part (1c) for accommodating the excitation coil (2) and, to the same side of the magnetic gap (4) as the vibration table (6), a degaussing coil accommodation part (1d) for accommodating the degaussing coil (3).

Description

Electrodynamic vibration generator

The present invention relates to an electrodynamic vibration generator used in a vibration test system or the like, and more particularly to its magnetic circuit structure.

As a type of magnetic circuit structure of a conventional electrodynamic vibration generator, a single yoke magnetic circuit as shown in FIG. 4 (see, for example, Patent Documents 1 and 2) or a double yoke as shown in FIG. Magnetic circuits (see, for example, Patent Documents 3 and 4) are known.

The single yoke magnetic circuit shown in FIG. 4 is housed in a yoke 61 made of a ferromagnetic material having an inner magnetic pole 61a, an outer magnetic pole 61b, and a coil housing 61c, and a coil housing 61c inside the outer magnetic pole 61b of the yoke 61. And a cylindrical magnetic gap 63 formed in a part of the closed magnetic path of the magnetic flux Φ ₁₁ excited by passing a current through the exciting coil 62, and the drive coil is included in the magnetic gap 63. 64 is arranged so that vibration is applied to the vibration table 65 integral with the drive coil 64 by an alternating current of a predetermined frequency flowing through the drive coil 64.

In this single yoke magnetic circuit, a leakage flux Φ ₁₂ is generated around the portion of the magnetic gap 63, which has a higher magnetic resistance than the ferromagnetic portions of the inner magnetic pole 61 a and the outer magnetic pole 61 b of the yoke 61. There is a problem of adversely affecting the DUT to be installed. In particular, when the device under test is a precision instrument, it may be required to avoid the influence of a magnetic field as much as possible.

On the other hand, the double yoke magnetic circuit shown in FIG. 5A includes a yoke 71 made of a ferromagnetic material having an inner magnetic pole 71a, an outer magnetic pole 71b, and two

coil storage portions

71c and 71d, and a coil inside the outer magnetic pole 71b of the yoke 71.

Exciting coils

72 and 73 accommodated in the

accommodating portions

71c and 71d, and cylindrical shapes formed in a part of a closed magnetic path of magnetic fluxes Φ ₂₁ and Φ ₂₂ excited by flowing a direct current through the

exciting coils

72 and 73 The drive coil 75 is disposed in the magnetic gap 74, and the vibration table 76 integrated with the drive coil 75 is vibrated by an alternating current flowing through the drive coil 75.

This double yoke magnetic circuit has an advantage that the magnetic flux 74 having a large magnetic resistance is inside the yoke 71, so that the leakage magnetic flux hardly appears outside the yoke 71. However, as shown in FIG. The base 76 has a plurality of ribs 76b for connecting the drive coil 75 that vibrates in the magnetic gap 74 to the external mounting base 76a, and openings 76c formed between the plurality of ribs 76b, and thus has a complicated shape. There is a problem of becoming.

In order to solve such a problem, Patent Document 5 discloses a single-magnet with a degaussing coil in which a demagnetizing coil is provided around the shaking table in order to reduce the influence of leakage magnetic flux on the DUT attached to the shaking table. A magnetic circuit with a yoke is described.

A single yoke magnetic circuit with a degaussing coil is shown in FIG. In this magnetic circuit, a demagnetizing coil 66 for generating a magnetic flux Φ ₁₃ that cancels the leakage magnetic flux Φ ₁₂ is provided around the vibration table 65 of the single yoke magnetic circuit shown in FIG. The subsequent configuration is the same as that of the single yoke magnetic circuit shown in FIG.

Japanese Patent Laying-Open No. 2005-91018 (Patent No. 4150648) JP 2000-121490 A (Patent No. 3895479) JP 2001-133357 A (Patent No. 3427119) International Publication No. 2009/130818 (Patent No. 5124017) JP 2005-517922 gazette

The single yoke magnetic circuit with the demagnetizing coil shown in FIG. 6 can reduce the leakage flux as compared with the single yoke magnetic circuit shown in FIG. 4, but the magnitude and direction of the magnetic flux Φ ₁₃ generated by the demagnetizing coil 66 are Since it is difficult to completely match the magnitude and direction of the leakage flux Φ ₁₂ , there is a problem that the leakage flux is larger than that of the double yoke magnetic circuit shown in FIG.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electrodynamic vibration generator having a magnetic circuit structure capable of reducing leakage magnetic flux as much as a double yoke magnetic circuit structure while having a single yoke magnetic circuit structure. .

In order to solve the above problems, the electrodynamic vibration generator of the present invention is:
An exciting coil for generating a static magnetic field;
A yoke made of a ferromagnetic material for forming a magnetic circuit and a magnetic gap by a static magnetic field generated by the exciting coil;
A drive coil for generating vibration disposed in the magnetic gap;
A vibration table formed integrally with the drive coil,
A demagnetizing coil for canceling a leakage magnetic flux out of a magnetic flux generated by the static magnetic field generated by the exciting coil is installed inside the yoke in the vicinity of the vibration table.

In the present invention, by applying a direct current to the exciting coil, a magnetic circuit (static magnetic field) is generated in the yoke surrounding the exciting coil. The yoke is provided with a magnetic gap. By passing an alternating current of a predetermined frequency through a drive coil arranged in the magnetic gap, the yoke is provided between a static magnetic field generated in the magnetic gap and an alternating current flowing through the drive coil. Based on Fleming's left-hand rule, the drive coil vibrates in a direction perpendicular to the direction of the magnetic flux. The drive coil is integrally provided with a vibration table, and the DUT attached to the vibration table vibrates at the frequency of the alternating current flowing through the drive coil. At this time, leakage magnetic flux is generated outside the magnetic circuit formed in the yoke due to the magnetic resistance of the magnetic gap, magnetic saturation of the yoke, etc. By generating a reverse direction magnetic flux with substantially the same size, the leakage magnetic flux is canceled out, thereby reducing the influence of the magnetic flux on the DUT. Since the degaussing coil is provided inside the yoke having a small magnetic resistance, the leakage magnetic flux can be greatly reduced as compared with the case where the degaussing coil is installed outside the yoke.

The yoke has an exciting coil housing part for housing the exciting coil on the opposite side of the vibrating table across the magnetic gap, and a degaussing coil housing for housing the degaussing coil on the vibrating table side of the magnetic gap. Since the magnetic flux generated by the exciting coil and the magnetic flux generated by the degaussing coil are superimposed in the same direction in the magnetic gap by providing the portion, there is no demagnetization in the magnetic gap due to the provision of the degaussing coil. Contributes to increased magnetic force.

The yoke includes a first yoke having the exciting coil housing portion opened upward, covers the opening of the exciting coil housing portion from above, the demagnetizing coil housing portion opens upward, and forms the magnetic gap. By having a second yoke having an inner periphery and a third yoke that covers the demagnetizing coil housing part from above, the exciting coil and the degaussing coil can be easily housed and the assembly is simplified.

According to the present invention, it is possible to obtain an electrodynamic vibration generator having a magnetic circuit structure capable of reducing a leakage magnetic flux as much as a double yoke magnetic circuit structure while having a single yoke magnetic circuit structure.

It is the schematic which shows the structure of the electrodynamic type vibration generator which concerns on this invention. FIG. 4 is a cross-sectional view taken along line AA of FIG. 3 showing an embodiment of the electrodynamic vibration generator according to the present invention. It is a top view which shows embodiment of the electrodynamic type vibration generator which concerns on this invention. It is the schematic which shows the example of the electrodynamic type vibration generator of the conventional single yoke magnetic circuit structure. It is the schematic which shows the example of the electrodynamic type vibration generator of the conventional double yoke magnetic circuit structure. It is a perspective view which shows the example of the vibration table used for the electrodynamic vibration generator of the conventional double yoke magnetic circuit structure. It is the schematic which shows the example of the electrodynamic vibration generator of the conventional single yoke magnetic circuit structure with a demagnetizing coil.

As shown in FIG. 1, an electrodynamic vibration generator according to the present invention includes a yoke 1 made of a ferromagnetic material having an inner magnetic pole 1a, an outer magnetic pole 1b, an exciting coil housing portion 1c, and a demagnetizing coil housing portion 1d, An excitation coil 2 for generating a static magnetic field in the yoke 1 housed in the excitation coil housing 1c, a degaussing coil 3 housed in the degaussing coil housing 1d, and a magnetic gap 4 formed in the yoke 1 are arranged. The structure has a drive coil 5 for generating vibration and a vibration table 6 to which a test object is attached, which is integrally connected to the drive coil 5 by a cylindrical body 7 made of a non-magnetic material. As the material of the yoke 1, a magnetic material having high magnetic permeability and high strength, for example, a low carbon steel such as SS400 can be suitably used. As a material of the vibration table 6, a non-magnetic high-strength metal such as an aluminum alloy, or a synthetic resin such as a carbon fiber can be suitably used.

In addition to the magnetic gap 4 in which the drive coil 5 is disposed, the yoke 1 is formed with a gap 8 for allowing the cylinder 7 connecting the drive coil 5 and the vibration table 6 to move up and down.

In FIG. 1, among the static magnetic fluxes formed in the yoke 1 by passing a direct current through the exciting coil 2, the main magnetic flux passing through the magnetic gap 4 is Φ _m1 , the magnetic flux passing through the gap 8 is Φ _m2 , and the vibration table. Let the leakage flux near 6 be Φ _L1 . Of the static magnetic field magnetic flux formed in the yoke 1 by passing a direct current through the demagnetizing coil 3, the main magnetic flux passing through the magnetic gap 4 and the gap 8 is Φ _c1 , and the canceling magnetic flux in the vicinity of the vibration table 6 is Φ _c2. And

In the present invention, the leakage flux Φ _L1 caused by the excitation coil 2 is canceled out by the cancellation flux Φ _c2 , so the leakage flux Φ _L1 and the cancellation flux Φ _c2 are equal in value and opposite in direction. By setting the current to flow through the leakage flux, the leakage magnetic flux in the vicinity of the vibration table 6 can be canceled.

Since the main magnetic flux Φ _m1 due to the exciting coil 2 and the main magnetic flux Φ _c1 due to the degaussing coil 3 are in the same direction in the magnetic gap 4, the magnetic flux density in the magnetic gap 4 is reduced by providing the demagnetizing coil 3. Rather, it contributes to an increase in magnetomotive force.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
2 and 3 show an electrodynamic vibration generator according to an embodiment of the present invention. The yoke 1 is divided into a first yoke 11, a second yoke 12, and a third yoke 13. FIG. And is integrally fixed with a bolt or the like. The first yoke 11 has a lower inner portion including the exciting coil storage portion 1c among the inner inner magnetic pole 1a and the outer magnetic pole 1b. The second yoke portion 12 has a middle portion of the outer magnetic pole 1b including the magnetic gap 4 and the demagnetizing coil storage portion 1d. The third yoke portion 13 is an upper portion of the outer magnetic pole 1b that covers the upper portion of the demagnetizing coil 3 housed in the degaussing coil housing portion 1d.

The vibration table 6 is made of a non-magnetic material such as plastic, preferably carbon fiber, integrally with the cylindrical body 7. An annular drive coil 5 is connected to the lower portion of the cylindrical body 7 so that it can move up and down in the magnetic gap 4. Placed in. A moving space is secured inside the exciting coil housing 1c below the magnetic gap 4 and inside the demagnetizing coil housing 1d above so that the drive coil 5 can freely move up and down.
In addition to the magnetic gap 4 in which the drive coil 5 is disposed, the yoke 1 is formed with a gap 8 for allowing the cylinder 7 connecting the drive coil 5 and the vibration table 6 to move up and down.

The upper portion of the yoke 1 is in contact with vertical walls 7a formed at a plurality of locations (four locations in the example of FIG. 3) on the upper portion of the cylindrical body 7 so as not to be laterally shaken when the vibration table 6 vibrates up and down. An upper support mechanism 20 having a guide roller 21 is provided. Further, a flange 31 is attached to the center of the bottom of the vibration table 6, and a ball spline 32 is attached to the lower part of the flange 31. The ball spline 32 includes a spline shaft provided with a transfer groove for a steel ball and an outer outer cylinder. A cage, a side ring, and a steel ball are incorporated in the outer cylinder, and the spline shaft moves smoothly up and down. It can be done. A shaft hole 33 for inserting the outer cylinder of the ball spline 32 is provided in the upper center portion of the yoke 1, and the lower support mechanism 30 is configured by the ball spline 32 and the shaft hole 33.

A bellows-like air spring 40 is provided between the bottom of the vibration table 6 and the top of the yoke 1 such that the bellows-like air spring 40 can extend and retract.

Air chambers

41 and 42 communicated with the inside of the air spring 40 above and below the shaft hole 33. Is formed. The air spring 40 supports the weight of the movable part including the test object attached to the vibration table 6 so that the position of the drive coil 5 is held at the center position in the height direction of the magnetic gap 4. The drive coil 5 vibrates up and down around the position.
The

air chambers

41 and 42 are installed for the purpose of alleviating pressure fluctuations to the air spring 40 when the drive coil 5 vibrates, and by increasing the volume of the

air chambers

41 and 42, The frequency can be lowered.
At the bottom of the yoke 1, vibration isolators 50 using a vibration isolating material such as an anti-vibration rubber 51 are provided at a plurality of locations, and vibration is difficult to propagate to a target to which the electrodynamic vibration generator of the present embodiment is attached. I am doing so.

In this embodiment, a magnetic circuit (static magnetic field) is generated in the yoke 1 surrounding the exciting coil 2 by passing a direct current through the exciting coil 2. The yoke 1 is provided with a magnetic gap 4, and a static magnetic field generated in the magnetic gap 4 and the drive coil 5 are caused to flow by passing an alternating current of a predetermined frequency through the drive coil 5 disposed in the magnetic gap 4. The drive coil 5 vibrates in a direction orthogonal to the direction of the magnetic flux due to the force acting between the alternating current and the alternating current. The drive coil 5 is integrally provided with a vibration table 6, and the device under test attached to the vibration table 6 vibrates at the frequency of the alternating current flowing through the drive coil 5. At this time, leakage magnetic flux is generated outside the magnetic circuit formed in the yoke 1 due to the magnetic resistance of the magnetic gap 4, magnetic saturation of the yoke 1, etc., but the degaussing coil 3 is located near the vibration table 6 inside the yoke 1. , And generating a magnetic flux in the opposite direction that is substantially the same size as the leakage magnetic flux, thereby canceling out the leakage magnetic flux, thereby reducing the influence of the magnetic flux on the DUT.

Here, an experimental example of the relationship between the magnetomotive force of the exciting coil 2, the magnetomotive force due to the current flowing through the degaussing coil 3 to cancel the leakage magnetic flux caused by the magnetomotive force, and the measured magnetic flux density at the observation site on the vibration table 6. Is shown below.

In this experimental example, the second example had the least leakage magnetic flux. It was found that the balance between the magnetomotive force of the exciting coil 2 and the magnetomotive force of the degaussing coil 3 is delicate, and the leakage magnetic flux increases when the balance is lost even at about 1%. For this reason, in an actual machine, it is preferable to set an appropriate magnitude of the magnetomotive force of the degaussing coil 3 by experiment.

The present invention is an electrodynamic vibration generator having a magnetic circuit structure capable of reducing leakage flux as much as a double yoke magnetic circuit structure while being a single yoke magnetic circuit structure. It can be suitably used for vibration tests.

DESCRIPTION OF SYMBOLS 1 Yoke 1a Inner magnetic pole 1b Outer magnetic pole 1c Excitation coil accommodating part 1d Demagnetizing coil accommodating part 2 Exciting coil 3 Demagnetizing coil 4 Magnetic gap 5 Drive coil 6 Shaking table 7 Cylindrical body 7a Vertical wall 8 Gap 11 1st yoke 12 2nd yoke 13 Third yoke 20 Upper support mechanism 21 Guide roller 30 Lower support mechanism 31 Flange 32 Ball spline 33 Shaft hole 40

Air spring

41, 42 Air chamber 50 Vibration isolator 51 Vibration isolator rubber

Claims

An exciting coil for generating a static magnetic field;
A yoke made of a ferromagnetic material for forming a magnetic circuit and a magnetic gap by a static magnetic field generated by the exciting coil;
A drive coil for generating vibration disposed in the magnetic gap;
A vibration table formed integrally with the drive coil,
An electrodynamic vibration generator characterized in that a degaussing coil for canceling a leakage magnetic flux out of a magnetic flux generated by the static magnetic field generated by the excitation coil is installed inside the yoke in the vicinity of the vibration table.
The yoke has an exciting coil housing part for housing the exciting coil on the opposite side of the vibrating table across the magnetic gap, and a degaussing coil housing for housing the degaussing coil on the vibrating table side of the magnetic gap. The electrodynamic vibration generator according to claim 1, further comprising a portion.
The yoke includes a first yoke having the exciting coil housing portion opened upward, covers the opening of the exciting coil housing portion from above, the demagnetizing coil housing portion opens upward, and forms the magnetic gap. The electrodynamic vibration generator according to claim 2, further comprising: a second yoke having an inner periphery, and a third yoke that covers the demagnetizing coil storage portion from above.
2. The electrodynamic vibration according to claim 1, wherein the vibration table is formed integrally with a cylindrical body, and the annular drive coil is connected to a lower portion of the cylindrical body so as to freely vibrate in the magnetic gap. Generator.
The electrodynamic vibration generator according to claim 1, wherein an upper support mechanism having guide rollers that abut against vertical walls formed at a plurality of positions on the upper portion of the cylindrical body is provided at an upper portion of the yoke.
An air spring is telescopically provided between the bottom of the vibration table and the top of the yoke, and communicates with the interior of the air spring above and below a shaft hole provided in the upper center of the yoke. The electrodynamic vibration generator according to claim 1, wherein an air chamber is formed.
The conductive vibration generator according to claim 1, wherein a vibration isolator is provided at a plurality of locations on the bottom of the yoke.