JP2633068B2 - Damping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a vibration damping device that alleviates vibration applied to a computer, a precision mechanical device, or a building or the like, and protects the device, the building, or the like from an earthquake or other disturbance vibration.
More particularly, the present invention relates to a vibration damping device using a braking force by eddy current or eddy current and magnetic hysteresis.

[Prior art]

2. Description of the Related Art Conventionally, as a vibration damping device for a mechanical device, a building, or the like, there is a device using a vibration-proof spring or a vibration-proof rubber. It is arranged between the fixed side and the like, and converts disturbance vibrations such as traffic vibrations, vibrations caused by construction work, earthquakes, wind quakes, and the like into gentle movements having a long cycle. As such an apparatus, there is an apparatus in which, for example, a ball bearing or a roller is incorporated at the bottom of a structure, or rubber or an air spring is used. However, the former has a large friction coefficient, so that the vibration isolation or damping action is not always sufficient. On the other hand, the latter has a certain natural vibration due to its weight and elastic coefficient, so there is no guarantee that it will not resonate with seismic waves. Also, a vibration damping device using an oil damper or a steel plate damper has been proposed. Changes the viscosity of
There is a disadvantage that the damping action becomes unstable. On the other hand, the latter has the advantage that maintenance is easy and there is no change due to temperature, but there is a drawback that there is reciprocal hysteresis and linearity is lacking. As a mechanical vibration damping device that solves the above-mentioned drawbacks, there is a proposal of a ball screw type vibration isolator with a magnetic damper (Transactions of the Japan Society of Mechanical Engineers, Vol. C, No. 51, No. 471 (Showa 60-11)).
reference). In this apparatus, a flat plate made of a conductive material such as copper or aluminum is provided at the tip of a ball screw, and a braking force due to an eddy current generated in the flat plate when the flat plate rotates in a magnetic field is used. In addition, as described above, as a device utilizing eddy current, a vibration proof and vibration isolating device using a combination of a rotating sphere and a conical or arc-shaped concave saucer is provided by a magnetic material and a conductor plate that is braked by the magnetic force of the magnetic material. Japanese Patent Application Laid-open No. Sho 63-2232 discloses a proposal in which a combination of different dampers is used.
No. 44).

[Problems to be solved by the invention]

The use of the above-described damper, which is a combination of a conductor plate and a magnetic material, has the advantage that periodic inspection work is not required and performance stability is guaranteed.
However, in the above-described conventional device, since the strength of the magnetic field interposed by the conductor plate is constant, there is also a problem that the vibration damping action or the vibration isolation action on the vibrating body is not always sufficient. Therefore, recently, a quasi-active vibration suppression method has been proposed in which a vibration detection sensor is attached to an object to be vibrated and the driving of a magnetic damper (electromagnet) is controlled by a detection signal of the sensor. However, if the magnetic damper is constituted by an electromagnet (for example, as described in
No. 223244), in order to obtain a braking force sufficient to brake a heavy moving body such as a mechanical device, a building, etc., the entire vibration damping device must be enlarged, and the responsiveness is increased. There is a problem that the temperature also decreases. SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems existing in the prior art and to provide a vibration damping device that can be reduced in size and has excellent vibration damping action.

[Means for Solving the Problems]

In order to achieve the above object, in the first aspect of the invention, a projection shape onto a plane including an axis of the housing is formed in a substantially U-shape with a ferromagnetic material on an inner peripheral surface of a hollow cylindrical housing. A plurality of yokes are arranged in the circumferential direction, a coil is wound around the yokes, and different poles are opposed to openings of the yokes via a gap to reduce the magnetic field strength to B.
A ball nut is inserted into the end inner surface of the housing so as to be non-rotatable and freely movable in the axial direction, and is formed into a hollow cylindrical shape from a conductive material by a ball screw screwed to the ball nut. A rotor is fixed, and the rotor is rotatably disposed in the gap. The direction of the current and the magnitude of the current are variably energized according to a signal from a sensor provided on the vibrating body, and 0 is supplied to the gap. A technical means of generating a magnetic field of ~ 2B was adopted. Next, in the second invention, on the inner surface of the intermediate portion of the housing formed in a hollow cylindrical shape, a plurality of yokes each formed in a circumferential direction by projecting a substantially H-shaped projection shape onto a plane including the axis of the housing from a ferromagnetic material. A coil is wound around the yoke, and a permanent magnet is formed in each opening of the yoke by opposing opposite poles through a gap to form a magnetic field strength of B. The inner surface of each part is fitted with a ball nut in a non-rotatable and axially movable manner, and a hollow cylindrical rotor made of a conductive material is fixed to a ball screw screwed to the ball nut, and these rotors are inserted into the gap. The coil is rotatably arranged, and the direction and magnitude of the current are variably supplied to the coil by a signal from a sensor provided on the vibrating body, so that a magnetic field of 0 to 2B can be generated in the gap. The technique of It adopted the means. In the third invention, a movable plate formed of a conductive material is fixed to the lower end of the vibrating body, a coil is wound around a comb-shaped yoke, and a comb-shaped end of the yoke is formed. A permanent magnet formed with a magnetic field strength of B so that a different pole appears adjacent to the yoke is provided, and this yoke is provided below the movable plate so that the magnetic field of the permanent magnet acts on the movable plate via a gap. A technique of arranging and variably energizing the coil in accordance with a signal of a sensor provided on the vibrated body and applying a current to the coil to generate a magnetic field of 0 to 2B in the gap. Tactics were adopted. In the first to third aspects, the pole piece may be fixed to the end of the permanent magnet. Further, the rotor or the movable plate is formed of a metal material such as aluminum or copper, but a part or all of them may be formed of a semi-hard magnetic material. That is, as the semi-hard magnetic material that can be used in the above invention, hardened steel (carbon steel, Cr steel, or Co steel having a slightly lower C content than magnet steel at 400 to 500 ° C.), α / γ Transformation type alloy (Fe-Cr-V (Cr) alloy, Fe-Mn alloy (C
o, Ni, Ti, Cr added), Fe-Ni alloy),
Alnico-based alloys (Fe-Ni-Al or Fe-Co-Ni-Al-based alloys deviating from a composition having a high coercive force), precipitation-type alloys (high Co-Fe-based alloys, Fe-Cu-based alloys, Fe-Mo-Co
Alloy) can be used. Among the above semi-hard magnetic materials, Fe-Cr-Co alloys (for example, JP-B-53-35536)
And No. 55-30052). Further, as the permanent magnet, a magnet having a large coercive force is desirable in order to oppose the demagnetizing field due to the coil and the eddy current. For example, it is preferable to use a rare earth permanent magnet.

[Action]

By variably controlling the magnetic field in the gap in which the rotor or the movable plate is provided by energizing the coil wound around the yoke, it is possible to accurately control the vibration of the vibrated body or the vibration isolation function. . When a part or the whole of the rotor or the movable plate is formed of a semi-hard magnetic material, a magnetic flux that advances later than the magnetization by the permanent magnet is generated due to a magnetic hysteresis inherent in the semi-hard magnetic material, and this delay is caused. As a result, a braking torque is generated in the rotor. This braking torque is substantially proportional to the area of the magnetic hysteresis loop inherent to the semi-hard magnetic material. The operation of the characteristic variable magnetic circuit in the above configuration is summarized as described above. (A) When no vibration occurs No current is applied to the coil, and only the magnetic field generated by the permanent magnet is applied to the rotor or the movable plate. That is, the movable side and the fixed side are locked. (B) The moment the vibration starts Vibration is detected by a sensor provided on the vibrated body,
The coil is energized by a signal from the sensor, and the magnetic field applied to the rotor or the movable plate is set to “0”. That is, the vibration is transmitted to the vibrated body in the state of (a). In this case, since the strength and direction of the magnetic field of each permanent magnet are known in advance, the coil may be energized so as to generate a magnetic field that cancels the magnetic field. (C) After the vibration is generated The intensity of the magnetic field applied to the rotor or the movable plate is changed in the range of 0 to 2B according to the magnitude of the generated vibration. In this case, 2B is the maximum magnetic field strength of the magnetic field obtained by combining the magnetic field of the permanent magnet and the magnetic field of the coil, and is set in accordance with the expected maximum vibration, the weight and structure of the vibrator, the magnetic characteristics of the rotor or the movable plate, and the like. 1/2 of the maximum magnetic field strength, that is, B is set as the magnetic field strength of the permanent magnet. Then, the value of the current flowing through the coil is controlled by a signal from the sensor, and the magnetic field generated by the coil is changed from -B to + B (absolute value B or less), so that the magnetic field is superimposed on the magnetic field generated by the permanent magnet. The magnetic field applied to the rotor or the movable plate can be changed in the range of 0 to 2B. In changing the magnetic field intensity applied to the rotor or the movable plate in the range of 0 to 2B (maximum magnetic field intensity) by the above-described operation, the magnetic field intensity of the permanent magnet and the coil may be half of the maximum magnetic field intensity. It becomes.

【Example】

FIG. 1 is a longitudinal sectional view showing an embodiment of the first invention, and FIGS. 2 and 3 are sectional views taken along lines AA and BB in FIG. 1, respectively. In these figures, 1
Is a housing formed of, for example, mild steel into a hollow cylindrical shape. Reference numeral 2 denotes a yoke, which is formed by using a ferromagnetic material such as mild steel to project a substantially U-shaped or substantially U-shaped projection shape onto a plane including the axis of the housing 1. Four pairs are fixed at equal intervals. A permanent magnet 4 is formed in an arc shape by, for example, a SmCo ₅ magnet (H-18B made by Hitachi Metals), and the yoke 2 is sandwiched by an epoxy-based adhesive with a gap 5 facing the opposite pole. To the inner surface of the opening. For example, four pairs of permanent magnets 4 are arranged at equal intervals in the circumferential direction, and are arranged such that adjacent magnetic poles having mutually different polarities appear on the surface.
Reference numeral 3 denotes a coil wound around the yoke 2 and variably connected to a DC power supply (both not shown) and the direction and magnitude of current through a control device. The control device is configured to be operable by a signal from a sensor (neither is shown) provided on the vibrated body. Reference numeral 6 denotes a stay pipe formed of, for example, mild steel in a hollow cylindrical shape and fixed coaxially to the left end surface of the housing 1. Next, 7 is an arm, 8 is a shaft, 9 is a detent, 10
Are ball nuts, which are coaxially combined with each other and are connected to the housing 1 via a slide bearing 11 and a thrust bearing 12.
And coaxially inserted into the stay pipe 6. That is, the arm 7, the detent 9 and the ball nut 10 are integrally fixed, and a ball screw 8a is engraved from the middle part of the shaft 8 to the left end.
Screw with 10. Therefore, the ball nut 10 is not rotated and the stay pipe 6 is not rotated.
The shaft 8 can be moved in the axial direction, and the shaft 8 is rotated by the axial movement of the ball nut 10. Next, a holding member 13 has an outer periphery formed into a cylindrical surface and is fixed to the right end of the shaft 8, and a hollow cylindrical rotor 14 is fixed to the outer periphery of the holding member 13. The rotor 14
Is formed of an aluminum alloy, and the permanent magnets 4, 4
It is formed so as to be rotatable in the gap 5 formed therebetween. Reference numeral 15 denotes a metal fitting which is rotatably connected to the arm 7 and the yoke 2 via a pin 16. According to the above configuration, the pair of metal fittings 15, 15 are connected to the movable side and the fixed side, respectively.
When vibration or relative movement in the left-right direction is applied between the shaft 8 and the stay pipe 6, the shaft 8 is rotated by the screwing of the ball nut 10 and the ball screw 8a. Therefore shaft 8
The holding member 13 fixed to the rotor also rotates, and the rotor 14
It rotates in the space 5 formed between the four. Since the Fe—Cr—Co-based alloy forming the rotor 14 is a conductive material, an eddy current is generated in the rotor 14 due to the rotation. The magnetic field induced by the eddy current acts in a direction opposite to that of the magnetic field generated by the permanent magnet 4, so that a braking action is generated on the rotor 14. On the other hand, the rotor 14
As a result, the N and S alternating magnetic fields are applied in the circumferential direction, so that a magnetic field hysteresis occurs in the rotor 14, and a hysteresis loss corresponding to the area of the magnetic hysteresis loop acts as a braking force of the rotor 14. That is, the horizontal movement of the arm 7 can be braked by superimposing a hysteresis loss in addition to the eddy current loss, and the arm 7 can function as a damper. In this case, at the moment when the vibration starts, a DC current is applied to the coil 3 from a DC power supply (neither is shown) through a control device by a signal of a sensor (not shown), and Set the magnetic field strength to zero. Then, the magnitude and direction of the DC current supplied to the coil 3 are controlled according to the subsequent vibration. Therefore, assuming that the magnetic field strength in the gap 5 by the permanent magnet is B, the magnetic field strength in the gap 5 can be changed in the range of 0 to 2B by controlling the magnitude direction of the DC current to the coil 3. . Therefore, the entire device can be made more compact as compared with the case where the same magnetic field intensity range is performed only by the electromagnet. FIG. 4 is a longitudinal sectional view of a main part showing a housing according to an embodiment of the second invention, and the same parts are denoted by the same reference numerals as in FIGS. 1 to 3. In FIG. 4, the yoke 2 is formed of a ferromagnetic material so that the shape of the yoke 2 projected onto a plane including the axis of the housing 1 is substantially E-shaped or H-shaped. The permanent magnet 4 is provided and fixed to an intermediate portion of the housing 1. In the gap 5 formed by the permanent magnet 4, a pair of left and right constituent members including a rotor having the same configuration as that of the above embodiment is disposed. With the above configuration, the same braking action as in the above embodiment can be expected, but by providing a pair of left and right movable members including the rotor as in this embodiment, the relative speed between the movable member and the stationary member is reduced by half. It is possible to apply a larger load and / or to downsize the entire device. In the above embodiment, the permanent magnet 4 is
Although an example is shown in which pairs are provided, an arbitrary number can be selected in consideration of braking torque and the like. The shape of the permanent magnet 4 can be not only an arc shape but also a rectangular parallelepiped shape. FIG. 5 is a front view of an essential part showing an embodiment of the third invention, and FIG.
The figure is a view taken along the line CC in FIG. In both figures, reference numeral 21 denotes a vibrated body, which is supported by a support member 22 made of an iron plate or other structural material. Reference numeral 23 denotes a movable plate, which is formed in a plate shape from a conductive material such as copper, and is fixed to the lower end of the vibrated body 21. Next, 24 is a yoke, which is made of a ferromagnetic material such as mild steel.
For example, the front shape is formed in a mountain shape or an E shape, and a spacer is formed.
It is arranged on the floor 26 via 25. Reference numeral 27 denotes a coil wound around the yoke 24 and variably connected to a direct current (both not shown) and the direction and magnitude of the current via a control device. Note that the control device is the same as that of the above-described embodiment.
It is configured to be operable by a signal from a sensor (not shown) provided at 21. Reference numeral 28 denotes a permanent magnet, which is formed of, for example, a SmCo ₅ magnet (H-18B made by Hitachi Metals) and is fixed to the end of the yoke 24 via an epoxy adhesive. 29 is a pole piece,
It is fixed to the end of the permanent magnet 28 via a similar adhesive. In addition, at the end of the yoke 24, the yoke 24 is formed so that a different pole appears adjacent to the yoke 24, and the yoke 24 is arranged so that the magnetic field of the permanent magnet 28 acts on the movable plate 23 via the gap 30. With the above configuration, when a relative movement in the horizontal direction occurs between the movable plate 23 fixed to the vibrated body 21 and the permanent magnet 28 due to an earthquake or the like, an eddy current is generated in the movable plate 23. As in the previous embodiment, a braking action occurs.
Further, the action of controlling the magnetic field strength in the air gap 30 by the coil 27 by the signal of the sensor (not shown) provided on the vibrated body 21 is the same as in the above-described embodiment. In the present embodiment, an example in which the pole piece 29 is fixed to the end of the permanent magnet 28 has been described. However, it is preferable to form the pole piece 29 in this manner because the magnetic flux from the permanent magnet 28 effectively acts in the movable plate 23. The yoke 24 may be formed in a comb shape in a front view, and four or more permanent magnets 28 may be provided. Further, three or more rows of the yokes 24 may be provided. When a part or the whole of the movable plate 23 is formed of a semi-hard magnetic material as in the above embodiment, a braking force by magnetic hysteresis can be added.

【The invention's effect】

Since the present invention has the configuration and operation as described above, it is possible to reduce the size or the size of the entire device as compared with a configuration in which the magnetic field generating member is configured only by electromagnets. In other words, by adopting a hybrid type of permanent magnet and electromagnet, the electric capacity of the coil can be halved, a cooling mechanism is not required, the inductance of the coil is small, the time constant is small, and Responsiveness and controllability can be improved.
In addition, a DC power supply having a small capacity can be operated sufficiently. Further, when a part or the whole of the rotor or the movable plate is formed of a semi-hard magnetic material, a braking force due to magnetic hysteresis can be superimposed in addition to a conventional braking force due to eddy current, and the entire apparatus can be miniaturized. There is an effect that it is possible to exhibit an excellent braking function or vibration damping function.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the first invention, FIGS. 2 and 3 are enlarged sectional views taken along lines AA and BB in FIG. 1, and FIG. FIG. 5 is a vertical sectional view of a main part showing a housing in an embodiment of the second invention, FIG. 5 is a front view of a main part showing an embodiment of the third invention, and FIG. 6 is a view taken along line CC in FIG. is there. 1: Housing, 2, 24: Yoke, 3, 27: Coil, 4, 28: Permanent magnet, 8a: Ball screw, 10: Ball nut, 14: Rotor, 2
3: Movable plate.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Teruo Umehara 5200 Sankajiri, Kumagaya-shi, Saitama Hitachi Metals, Ltd. Kumagaya Plant (56) References JP-A-63-312536 (JP, A) (JP, U) Japanese Utility Model Showa 53-146839 (JP, U) Japanese Utility Model Utility Model Showa 62-34242 (JP, U)

Claims (4)

(57) [Claims] 1. A plurality of yokes each having a substantially U-shape projected on a plane including an axis of a housing made of a ferromagnetic material and arranged in a circumferential direction on an inner peripheral surface of a housing formed in a hollow cylindrical shape. A coil is wound around the yoke, and a permanent magnet is formed in the opening of the yoke with different poles facing each other via a gap to form a magnetic field strength of B. A ball nut is provided on the inner surface of the end of the housing. Is inserted non-rotatably and axially movably, a rotor formed into a hollow cylindrical shape by a conductive material is fixed to a ball screw screwed into a ball nut, and the rotor is rotatably disposed in the gap. The vibration control device is characterized in that a current direction and a magnitude of the current are variably supplied to the coil by a signal of a sensor provided on the vibrating body, and a magnetic field of 0 to 2B can be generated in the gap. apparatus. 2. A plurality of yokes each having a substantially H-shape projected on a plane including an axis of the housing made of a ferromagnetic material are arranged on an inner surface of an intermediate portion of a hollow cylindrical housing in a circumferential direction. A coil is wound around the yoke, and permanent magnets are formed in each opening of the yoke with different poles facing each other via a gap to form a magnetic field strength of B. A ball nut is inserted in a non-rotatable and axially movable manner, and a hollow cylindrical rotor made of a conductive material is fixed to a ball screw screwed to the ball nut, and these rotors are rotatably arranged in the gap. The direction of the current and the magnitude of the current are variably energized to the coil by the signal of the sensor provided on the vibrating body, and it is configured to generate a magnetic field of 0 to 2B in the gap. Damping device 3. A movable plate formed of a conductive material is fixed to a lower end of a vibrating body, and a coil is wound around a comb-shaped yoke, and is adjacent to a comb-shaped end of the yoke. And a yoke is provided below the movable plate through a gap so that the magnetic field of the permanent magnet acts on the movable plate. The direction of the current and the magnitude of the current are variably supplied to the coil by a signal of a sensor provided on the vibrating body, and a magnetic field of 0 to 2B is generated in the gap. Damping device. 4. The vibration damping device according to claim 1, wherein a pole piece is fixed to an end of the permanent magnet.