JP7136727B2 - Malfunction determination device for eddy current dampers - Google Patents

Description

The present invention is an eddy current damper that suppresses the vibration of a structure or the like by applying the Lorentz force due to eddy currents as a braking force to a conductive member that rotates in the magnetic field of a permanent magnet as the structure or the like vibrates. relates to an abnormality determination device for determining an abnormality of

As a conventional eddy current damper, for example, one disclosed in Patent Document 1 is known. This damper is of a ball screw type, and includes an outer cylinder and an inner cylinder respectively connected to a supporting body and a supported body of a structure, a screw shaft rotatably supported by the outer cylinder, and fixed to the inner cylinder. and a ball nut screwed onto the screw shaft. Furthermore, it has a conductive member fixed to the outer peripheral surface of the screw shaft, and a permanent magnet fixed to the inner peripheral surface of the outer cylinder and facing the conductive member.

In this damper, when the supporting body and the supported body of the structure are displaced relative to each other during an earthquake or the like, the relative displacement is converted into rotational motion of the screw shaft, and the conductive member integral with the screw shaft is driven by the magnetic field of the opposing permanent magnet. rotate inside. Along with this, eddy currents are generated in the conductive members, and the Lorentz force due to the interaction between the eddy currents and the magnetic field of the permanent magnet acts on the conductive members as a damping force, thereby damping the vibration energy and causing the structure to vibrate. is suppressed.

Japanese Patent Publication No. 5-86496

Due to the configuration of the eddy current damper as described above, unless the magnetic flux density of the magnetic field passing through the conductive member is maintained as designed, the required damping performance cannot be ensured, and the vibration suppression effect of the structure cannot be sufficiently obtained. can't get to On the other hand, the phenomenon in which the magnetic flux density decreases is generally recognized and is called "demagnetization". It is classified into internal demagnetization due to the influence of the magnetic field generated inside, temperature demagnetization due to temperature change, etc.

Of these demagnetizations, temperature demagnetization has the greatest impact on damping performance. For example, when the temperature of the permanent magnet rises to 120° C., the damping performance of the damper begins to deteriorate. Therefore, when the structure is repeatedly deformed by long-period ground motion or the like, the temperature of the permanent magnet rises to the above temperature due to energy absorption, which may adversely affect the damping performance. In addition, once temperature demagnetization occurs, even if the temperature of the permanent magnet decreases after that, the magnetic flux density does not recover, and the magnetic flux density decreases step by step each time the temperature of the permanent magnet rises to the above temperature. and the damping performance is degraded. Thus, the temperature of the permanent magnet has a very large effect on the magnetic flux density and damping performance of the eddy current damper. However, in the above-described conventional eddy current damper, it is not possible to determine whether the eddy current damper is abnormal because it is not assumed that the magnetic flux density will decrease due to such temperature demagnetization.

In addition, even if the magnetic flux density is normal, the relative rotation between the permanent magnet and the conductive member may occur due to mechanical factors such as friction, contact, and catching with other members due to adhesion of powder of the permanent magnet, for example. may be disturbed, leading to lack of rotation or inability to rotate. Even in this case, the required damping performance cannot be secured, and the vibration suppressing effect cannot be maintained. A conventional eddy current damper does not assume such an abnormal operating state, and cannot make a judgment of it.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an eddy current damper abnormality determination apparatus capable of accurately determining an abnormality in the magnetic flux density of a permanent magnet in an eddy current damper. intended to

In order to achieve this object, the invention according to claim 1 generates an eddy current in a conductive member that relatively rotates in a magnetic field of a permanent magnet as a structure vibrates, and suppresses the Lorentz force caused by the eddy current. An abnormality determination device for determining abnormality of an eddy current damper that attenuates vibration energy by acting as a power source, comprising magnetic flux density detection means for detecting the magnetic flux density of a magnetic field passed by a conductive member; and the detected magnetic flux. and a first determination means for determining an abnormality in the magnetic flux density of the magnetic field based on the density.

In the eddy current damper of the present invention, an eddy current is generated in a conductive member that relatively rotates in the magnetic field of a permanent magnet as the structure vibrates, and the Lorentz force generated by this eddy current acts as a damping force. , the vibrational energy is damped. According to the abnormality determination device of the present invention, the actual magnetic flux density of the magnetic field passed by the conductive member is detected, and based on the detected magnetic flux density, abnormality of the magnetic flux density of the permanent magnet is determined. Therefore, regardless of the cause of the decrease in magnetic flux density (demagnetization), abnormalities in the magnetic flux density of the permanent magnets in the eddy current damper can be accurately determined at all times, not limited to earthquakes.

According to a second aspect of the present invention, there is provided an eddy current damper abnormality determination apparatus according to the first aspect, further comprising temperature detection means for detecting the temperature of the permanent magnet, wherein the first determination means comprises: It is characterized by determining whether there is a possibility that an abnormality in the magnetic flux density of the magnetic field will occur based on the temperature.

According to this configuration, based on the detected temperature of the permanent magnet, it is determined whether or not there is a possibility that an abnormality in the magnetic flux density of the magnetic field will occur. As described above, the temperature of the permanent magnet has a very large effect on the decrease in magnetic flux density (temperature demagnetization). Density does not recover. From this point of view, according to the present configuration, it is possible to predictably and appropriately determine whether there is a risk of occurrence of an abnormality in the magnetic flux density of the magnetic field based on the actual temperature of the permanent magnet detected. can.

The invention according to claim 3 is the eddy current damper abnormality determination device according to claim 1 or 2, wherein the earthquake occurrence determination means for determining whether or not an earthquake has occurred; A current sensor for detecting the generated induced current, a rotational speed detection means for detecting the relative rotational speed between the permanent magnet and the conductive member, and the detected induced current and rotation when it is determined that an earthquake has occurred and second determination means for determining an abnormality in the operating state of the eddy current damper based on the speed.

According to this configuration, it is determined whether or not an earthquake has occurred, the induced current generated in the coil provided in the conductive member is detected, and the relative rotational speed between the permanent magnet and the conductive member is detected. Then, when it is determined that an earthquake has occurred, based on the detected eddy current and rotational speed, it is determined whether the eddy current damper is operating abnormally. As described above, even when the magnetic flux density of the permanent magnet is normal, mechanical factors such as friction with other members, contact, and catching hinder the relative rotation of the permanent magnet and the conductive member. Insufficient or ineffective, and abnormal operation of the eddy current damper may occur.

On the other hand, if the eddy current damper is in a normal operating state, the relative rotational speed between the permanent magnet and the conductive member, the magnitude (current value) of the induced current generated in the coil provided in the conductive member, and the Lorentz A predetermined relationship is established between the forces. From this point of view, according to the present configuration, an abnormality in the operating state of the eddy current damper is determined based on the actual detected induced current and rotation speed, so that the abnormality determination can be performed with high accuracy. In addition, since the abnormality determination of the operating state is performed only when it is determined that an earthquake has occurred, it is possible to reliably avoid erroneous determination in a situation where the eddy current damper is not operating.

According to a fourth aspect of the present invention, there is provided the eddy current damper abnormality determination apparatus according to any one of the first to third aspects, further comprising display means for displaying the determination result of the abnormality of the eddy current damper. do.

According to this configuration, the result of the abnormality determination by the first determination means and/or the second determination means is displayed on the display means. From this display, it is possible to easily grasp whether or not an abnormality has occurred in the eddy current damper, the possibility of occurrence, and which of the magnetic flux density and/or the operating state has occurred, so that the abnormality can be dealt with appropriately. .

The invention according to claim 5 is the eddy current damper abnormality determination device according to any one of claims 1 to 4, wherein the eddy current damper includes a screw shaft having a thread groove formed thereon, and a plurality of A ball screw type that has a nut member that is rotatably screwed via a ball, and converts the relative displacement between the screw shaft and the nut member due to the vibration of the structure into relative rotational motion between the conductive member and the permanent magnet. is a damper of

According to this configuration, the eddy current damper is a ball screw damper that converts relative displacement between the screw shaft and the nut member due to vibration of the structure into relative rotational motion between the conductive member and the permanent magnet. . By applying the abnormality determination device of the present invention to such a ball screw type eddy current damper, the effects described above can be effectively obtained.

The invention according to claim 6 is the eddy current damper abnormality determination device according to any one of claims 1 to 4, wherein the eddy current damper is slidably provided in a cylinder filled with working fluid. It has a piston and a gear motor provided in a communication passage that communicates with the cylinder. It is a gear motor type damper that converts the relative rotational motion of the

According to this configuration, the eddy current damper converts the flow of the working fluid in the communication path generated by the sliding of the piston due to the vibration of the structure into the relative rotational motion of the conductive member and the permanent magnet by the gear motor. It is a gear motor type damper that converts. By applying the abnormality determination device of the present invention to such a gear motor type eddy current damper, the effects described above can be effectively obtained.

1 is a longitudinal sectional view of an eddy current damper (ball screw type) according to a first embodiment of the present invention; FIG. FIG. 2 is a partially enlarged cross-sectional view showing the arrangement of a plurality of permanent magnets and magnetic sensors in the damper of FIG. 1 and the state of generation of magnetic lines of force; It is a figure which shows roughly the example which applied the damper to the structure. It is a block diagram which shows the abnormality determination apparatus of a damper. FIG. 4 is a diagram showing an electric circuit of a damper; 4 is a flowchart showing abnormality determination processing of the magnetic flux density of a permanent magnet; 4 is a flow chart showing a process for determining abnormality of the operating state of a damper; 8 is a map used in the abnormality determination process of FIG. 7; FIG. 10 is a partially cutaway vertical cross-sectional view of an eddy current type damper (gear motor type) according to a second embodiment of the present invention; FIG. 10 is a partially enlarged cross-sectional view showing the arrangement of a plurality of permanent magnets and magnetic sensors in the damper of FIG. 9 and the state of generation of magnetic lines of force;

Preferred embodiments of the present invention will be described in detail below with reference to the drawings. 1 and 2 show an eddy current damper and its abnormality determination device according to a first embodiment of the present invention. This eddy current type damper (hereinafter referred to as "damper") 1 is of a ball screw type and comprises a ball screw 11, an inner cylinder 12, an outer cylinder 13, a plurality of permanent magnets 14, and the like.

The ball screw 11 has a threaded shaft 11a and a large number of balls 11b accommodated in the thread groove of the threaded shaft 11a. The screw shaft 11a is immovably connected to the first flange 17 via a universal joint 17a at its outer end.

The inner cylinder 12 is made of a ferromagnetic material (for example, steel), and has a nut portion 12a formed on the inner peripheral surface of one end side thereof with which the screw shaft 11a is screwed. The inner cylinder 12 is rotatably supported by the outer cylinder 13 via bearings 19, 19 at both ends.

The outer cylinder 13 is made of a conductive material (for example, steel) (a conductive member) and arranged so as to cover the outer peripheral side of the inner cylinder 12 . Further, an end plate 20 and a second flange 21 are provided so as to cover the flush end surfaces of the inner cylinder 12 and the outer cylinder 13 , and the outer cylinder 13 is screwed to the end plate 20 and the second flange 21 . 22 is fixed.

A plurality of permanent magnets 14 are attached to the outer peripheral surface of the inner cylinder 12 and arranged in three rows at three positions in the axial direction of the damper 1. They are arranged at equal intervals in the direction, and face the inner peripheral surface of the outer cylinder 13 with a predetermined interval. Further, as shown in FIG. 2, the magnetic poles of the permanent magnets 14 are arranged in the radial direction of the inner cylinder 12, and the directions of the magnetic poles are set so as to differ between each two adjacent permanent magnets 14, 14. .

For example, as shown in FIG. 3, the damper 1 having the above configuration is arranged in a portal frame composed of the upper and lower beams BU and BL and the left and right pillars PL and PR of the structure B, and is connected to the upper beam BU. V-shaped brace BR and the corners of the lower beam BL and left pillar PL are installed horizontally via first and second flanges 17 and 21 .

From this state, when the structure B vibrates during an earthquake or the like, and a horizontal relative displacement occurs between the upper and lower beams BU and BL, the screw shaft 11a and the nut portion 12a connected to them are formed. Relative linear motion with the inner cylinder 12 is converted into rotational motion of the inner cylinder 12 , and the inner cylinder 12 and the plurality of permanent magnets 14 rotate with respect to the outer cylinder 13 .

Along with this, as shown in FIG. 2, an eddy current is generated on the inner surface of the outer cylinder 13 (conductive member) that relatively rotates within the magnetic field of the permanent magnet 14 . A Lorentz force is generated by interaction between the eddy current and the magnetic field of the permanent magnet 14, and the Lorentz force acts on the inner cylinder 12 as a braking force in the direction opposite to the direction of rotation, thereby exerting a damping effect. and the vibration of the structure B is suppressed.

Next, an abnormality determination device for the damper 1 will be described. As shown in FIG. 4, the abnormality determination device of this embodiment includes a magnetic sensor 31, a magnet temperature sensor 32, a current sensor 33, first and second acceleration sensors 34 and 35, and detection results of these sensors 31 to 35. It is composed of an ECU (electronic control unit) 30 that executes abnormality determination processing in response to, for example, a display 41 that displays the result of the abnormality determination.

As shown in FIG. 2, the magnetic sensors 31 are provided on the inner peripheral surface of the outer cylinder 13 in the same number as the permanent magnets 14, and are arranged at regular intervals in the circumferential direction. The magnetic sensor 31 is composed of an MR sensor or an AMR sensor using a magnetoresistive effect element, a Hall sensor using a Hall element, or the like, detects the magnetic flux density DM passing through the outer cylinder 13, and outputs the detection signal. Output to the ECU 30 . Further, the ECU 30 calculates the rotation speed VM of the inner cylinder 12 based on the inputted detection signal and from the period of change of the magnetic flux density DM.

As the magnetic sensor 31, different types may be used for different purposes. For example, a magnetoresistive element type MR sensor or the like may be used for detecting the magnetic flux density DM, and a Hall sensor may be used for calculating the rotational speed. Also, the number of magnetic sensors 31 is not necessarily the same as the number of permanent magnets 14, and may be increased or decreased as appropriate. Furthermore, the magnetic sensors 31 can be provided for all three rows of permanent magnets 14 shown in FIG. 1, or for only one or two rows of permanent magnets 14 . The magnetic sensor 31 may be arranged so as to face the permanent magnet 14 , or may be arranged at a predetermined position slightly displaced in the axial direction of the ball screw 11 . Moreover, it is desirable that the magnetic sensor 31 be made of a material that can withstand the temperature rise of the permanent magnet 14 .

The magnet temperature sensor 32 is composed of, for example, a thermistor. As shown in FIG. 1 , the magnet temperature sensors 32 are arranged at predetermined positions slightly displaced from the three rows of permanent magnets 14 in the axial direction, and provided on the inner peripheral surface of the outer cylinder 13 . Each magnet temperature sensor 32 detects the temperature around the permanent magnet 14 as a magnet temperature TM and outputs the detection signal to the ECU 30 .

A plurality of coils 36 are provided on the outer cylinder 13 . These coils 36 are for regenerating electrical energy, are provided in the same number as the permanent magnets 14, and are constructed so that an induced current generated by a varying magnetic field flows. The current sensor 33 detects the magnitude of this induced current as a current value IS and outputs it to the ECU 30 .

These coils 36 are connected in series with each other, and as shown in FIG. 5, a capacitor 38, a battery 39, a switch 40 and a magnetic sensor 31 are connected in series in this order. With this configuration, the electrical energy generated by the induced current flowing through the coil 36 when the damper 1 operates is regenerated in the capacitor 38 and stored as electric power. Also, by turning on the switch 40 when the charging rate SOC of the battery 39 becomes equal to or less than a predetermined threshold value, for example, the power stored in the capacitor 38 can be charged into the battery 39 .

Further, as shown in FIG. 3, the upper beam BU and the lower beam BL of the structure B are provided with first and second acceleration sensors 34 and 35, respectively. The first and second acceleration sensors 34 and 35 detect horizontal acceleration ABU due to vibration of the upper beam BU (hereinafter referred to as "upper beam acceleration") and horizontal acceleration due to vibration of the lower beam BL (hereinafter referred to as "lower beam acceleration ) are detected, and their detection signals are output to the ECU 30 .

The ECU 30 is composed of a microcomputer having a CPU, RAM, ROM, I/O interface, and the like. The ECU 30 determines abnormality of the damper 1 according to the detection signals from the sensors 31 to 35 and the like, according to the program stored in the ROM, and performs abnormality determination processing of the magnetic flux density of the permanent magnet 14 and abnormality determination of the operating state of the damper 1. Execute the judgment process.

Among them, FIG. 6 shows the abnormality determination processing of the magnetic flux density. This process is always repeatedly executed at predetermined time intervals regardless of whether an earthquake has occurred or not. In this process, first, in step 1 (illustrated as “S1”; the same applies hereinafter), the average magnetic flux density DMAVE is calculated by arithmetically averaging the plurality of magnetic flux densities DM1 to DMn detected by the respective magnetic sensors 31.

Next, it is determined whether or not the calculated average magnetic flux density DMAVE is equal to or greater than a predetermined threshold value DLMT (step 2). When the answer is NO and DMAVE<DLMT, it is determined that the magnetic flux density of the plurality of permanent magnets 14 has decreased as a whole and that an abnormality has occurred. Then, in order to indicate this, the magnetic flux density abnormality flag F_DMNG is set to "1" (step 3), and this process is terminated.

If the answer to step 2 is YES, it is determined whether all of the plurality of magnetic flux densities DM1 to DMn are equal to or greater than the threshold value DLMT (step 4). When the answer is NO and at least one of the magnetic flux densities DM1 to DMn is below the threshold value DLMT, it is determined that the magnetic flux density of some of the permanent magnets 14 has decreased and an abnormality has occurred, Proceeding to step 3, the magnetic flux density abnormality flag F_DMNG is set to "1".

When the answer to step 4 is YES, it is determined whether all of the plurality of magnet temperatures TM1 to TMm detected by the respective magnet temperature sensors 32 are below a predetermined temperature TLMT (for example, 90° C.) (step 5). If the answer is NO and at least one of the magnet temperatures TM1 to TMm exceeds the predetermined temperature TLMT, it is determined that there is a possibility that the permanent magnet 14 has a decrease in magnetic flux density due to temperature (temperature demagnetization). Then, the process proceeds to step 3 to set the magnetic flux density abnormality flag F_DMNG to "1".

On the other hand, when the answer to step 5 is YES, that is, when the conditions of steps 2, 4 and 5 are all satisfied, it is determined that the magnetic flux density of the permanent magnet 14 is normal, and the magnetic flux density abnormality flag F_DMNG is set to " 0" (step 6), and the process ends. The result of the abnormality determination obtained by the above processing is appropriately displayed on the display 41 by, for example, words meaning "abnormal" or "abnormal".

Next, referring to FIG. 7, the operation state abnormality determination process of the damper 1 will be described. This process is repeatedly executed at predetermined time intervals. In this process, first, in step 11, the absolute value |ABU| or |ABL| Determine whether it is larger or not. If the answer is NO and both the upper and lower beam accelerations ABU and ABL are almost 0, it is determined that the structure B has not been shaken by an earthquake or the like, and this process ends.

When the answer to step 11 is YES, it is determined that vibrations due to an earthquake or the like are occurring in the structure B, and the operational state of the damper 1 is determined to be substantially abnormal in the next step 12 and subsequent steps. First, in step 12, based on the detection signal of the magnetic sensor 31, the rotation speed VM of the inner cylinder 12 is calculated.

Next, a reference current amount IREF is calculated by searching the map shown in FIG. 8 according to the calculated rotational speed VM of the inner cylinder 12 (step 13). This reference current amount IREF corresponds to the magnitude of the induced current assumed to occur in the coil 36 provided in the outer cylinder 13 with respect to the rotational speed VM of the inner cylinder 12 .

Next, a value (=IREF·(1+(α/100)) and a discounted value (=IREF·(1−(α/100)) obtained by increasing the reference current amount IREF by a predetermined ratio α (for example, 10%) are calculated as the upper limit current amount ILMTH and the lower limit current amount ILMTL, respectively (step 14) From the above calculation method, the relationship between the reference current amount IREF and the upper/lower limit current amounts ILMTH and ILMTL is as shown in FIG. shown in

Next, whether or not the current value IS detected by the current sensor 33 is equal to or greater than the lower limit current amount ILMTL and equal to or less than the upper limit current amount ILMTH, that is, whether or not it is within a predetermined range centered on the reference current amount IREF. (step 15).

If the answer is YES, ILMTL≤IS≤ILMTH is established, and the actual current value IS due to the induced current generated in the coil 36 provided in the outer cylinder 13 is within a predetermined range, the damper 1 operates normally. Determine that it is working. Then, in order to indicate this, the operating state abnormality flag F_DPNG is set to "0" (step 16), and this process is terminated.

On the other hand, when the answer to step 15 is NO, IS<ILMTL or IS>ILMTH is established, and the actual current value IS in the coil 36 of the outer cylinder 13 is out of the predetermined range, the operating state of the damper 1 is abnormal. Determine that there is. Then, the operating state abnormality flag F_DPNG is set to "1" (step 17), and this processing is terminated. The result of abnormality determination obtained by the above processing is displayed on the display 41 as appropriate.

As described above, according to the magnetic flux density abnormality determination process (FIG. 6) of the present embodiment, the actual magnetic flux density DM of the permanent magnet 14 through which the outer cylinder 13, which is a conductive member, is detected, and the detected magnetic flux Abnormalities in the magnetic flux density of the permanent magnet 14 are determined based on the density DM. Therefore, regardless of the cause of the decrease in magnetic flux density (demagnetization), abnormalities in the magnetic flux density of the permanent magnets 14 in the damper 1 can be accurately determined at all times, not limited to earthquakes.

Further, based on the detected actual temperature of the permanent magnet 14 (magnet temperature TM), it is determined whether or not there is a possibility that an abnormality in the magnetic flux density will occur. abnormality (temperature demagnetization) can be predicted and appropriately determined.

Furthermore, according to the operation state abnormality determination process (FIG. 7), when it is determined that an earthquake has occurred, the damper 1 Abnormality determination of the operating state can be performed with high accuracy. In addition, since the abnormality determination of the operating state is performed only when it is determined that an earthquake has occurred, it is possible to reliably avoid erroneous determinations when the damper 1 is not operating.

In addition, since the result of the above-described abnormality determination of the magnetic flux density and the operating state is displayed on the display 41, the presence or possibility of occurrence of an abnormality and whether the abnormality of the magnetic flux density or the operating state has occurred can be determined from this display. can be easily grasped, and the abnormality can be appropriately dealt with.

Next, an eddy current damper and an abnormality determination device therefor according to a second embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG.

This eddy current type damper (hereinafter referred to as "damper") 51 is of a gear motor type, and includes a cylinder 52, a piston 53 slidably provided in the cylinder 52, a piston 53 bypassed, and the cylinder 52 a communication passage 54 communicating inside, a gear motor 55 arranged in the communication passage 54, a flywheel 62 integrally connected to a rotating shaft 56 of the gear motor 55, and a plurality of permanent magnets provided in the flywheel 62 64, a casing 63 that houses the flywheel 62 and a plurality of permanent magnets 64, and the like.

The cylinder 52 integrally has a cylindrical peripheral wall 52a and first and second end walls 52b and 52c provided at the left and right ends thereof. The first end wall 52b is concentrically and integrally provided with a hollow rod accommodating portion 52f protruding outward. It is

The piston 53 is provided slidably in the axial direction inside the cylinder 52, and the inside of the cylinder 52 is divided into a first fluid chamber 52d on the left side in FIG. 9 and a second fluid chamber 52e on the right side. These first and second fluid chambers 52d and 52e and the communication passage 54 are filled with working fluid HF. The working fluid HF is composed of normal working oil or the like having moderate viscosity.

A piston rod 60 is provided integrally with the piston 53 . The piston rod 60 extends on both sides of the piston 53 and extends outward through seals through holes in the first and second end walls 52b, 52c in a liquid-tight manner. One end of the piston rod 60 is housed in the rod housing portion 52f of the cylinder 52, and the other end is provided with a second fixture FL2 via a universal joint.

Two communication holes 53a, 53a are formed through the piston 53 in the axial direction, and a relief valve 61 is provided in each of the communication holes 53a. The relief valves 61, 61 have the same configuration as each other, are configured as normally closed valves, and have a valve body and a spring that biases the valve body in the valve closing direction.

One relief valve 61 closes one communication hole 53a until the pressure of the working fluid HF in the first fluid chamber 52d reaches the first predetermined pressure, and when the pressure reaches the first predetermined pressure, the communication hole 53a is opened. As a result, the pressure in the first fluid chamber 52d is released toward the second fluid chamber 52e and is limited to the first predetermined pressure or less. Similarly, the other relief valve 61 closes the other communication hole 53a until the pressure in the second fluid chamber 52e reaches the first predetermined pressure, and when the pressure reaches the first predetermined pressure, the communication hole 53a is closed. open the As a result, the pressure in the second fluid chamber 52e is released toward the first fluid chamber 52d and is limited to the first predetermined pressure or less.

The communication passage 54 communicates with the first and second fluid chambers 52d, 52e through communication ports 52h, 52h formed at both ends of the peripheral wall 52a of the cylinder 52. As shown in FIG.

The gear motor 55 is arranged in the communication path 54 , converts the flow of the working fluid HF in the communication path 54 into rotary motion, and outputs it from the rotating shaft 56 . The gear motor 55 is of an internal contact type, and has a housing 74 , a rotatable gear 75 accommodated in the housing 74 , and the rotating shaft 56 . As the gear motor 55, a circumscribed type may be used.

The housing 74 is provided so as to communicate with the communication path 54, and the casing 63 is integrally attached to its upper surface. The gear 75 is driven by the pressure of the working fluid HF flowing into the housing 74 to rotate about the vertical axis. The rotary shaft 56 is provided coaxially and integrally with the gear 75, extends upward, passes through holes in the housing 74 and the casing 63 in a sealed state, and is rotatably supported by these.

The flywheel 62 is made of a ferromagnetic material (for example, steel), has a disk shape, and is coaxially and integrally provided with the rotating shaft 56 .

As shown in FIGS. 9 and 10, a plurality of permanent magnets 64 (eight in this example) are provided back-to-back at the same position on the outer periphery of the upper surface and the lower surface of the flywheel 62, respectively. are evenly spaced. The magnetic poles of the permanent magnet 64 are arranged in a direction perpendicular to the main surface of the flywheel 62 (vertical direction), and the magnetic poles are oriented between two adjacent permanent magnets 64, 64 in the upper surface or the lower surface. , and the two permanent magnets 64, 64 on the upper and lower surfaces facing back to each other are set to be the same.

The casing 63 is made of a conductive material (such as steel) (a conductive member), integrally has an upper wall 63a, a lower wall 63b and a peripheral wall 63c, and is non-rotatably fixed to the housing 74 of the gear motor 55. . The casing 63 accommodates the flywheel 62 and the permanent magnets 64 , the upper wall 63 a and the lower wall 63 b facing the upper and lower permanent magnets 64 respectively, and the peripheral wall 63 c facing the peripheral edge of the flywheel 62 . In addition, the casing 63 seals the rotating shaft 56, thereby serving as a shield to prevent the magnetism generated by the permanent magnet 64 from leaking to the outside.

Although not shown, the damper 51 having the above configuration is composed of the upper and lower beams BU and BL and the left and right pillars PL and PR of the structure B, like the damper 1 of the first embodiment shown in FIG. It is arranged in the portal frame and installed horizontally between the V-shaped brace BR and the corners of the lower beam BL and the left pillar PL via first and second fixtures FL1 and FL2.

From this state, when a horizontal relative displacement occurs between the upper and lower beams BU and BL as the structure B vibrates during an earthquake or the like, the piston 53 moves from the neutral position shown in FIG. It slides in the cylinder 52 with a direction and stroke according to . As the piston 53 slides, the working fluid HF in the first or second fluid chambers 52 d and 52 e is pushed out by the piston 53 and flows into the communication passage 54 .

The flow of the working fluid HF in the communication path 54 is converted into rotational motion of the gear 75 by the gear motor 55, thereby rotating the flywheel 62 integrated with the rotating shaft 56, and rotating inertia mass effect (inertial force ) is exhibited. Moreover, the viscous damping effect (viscous force) is exhibited by the viscous resistance when the working flow HF flows through the communication passage 54 .

Furthermore, by rotating the plurality of permanent magnets 64 together with the flywheel 62, the casing 63, which is a conductive member, relatively rotates within the magnetic field of the permanent magnets 64, as shown in FIG. As a result, eddy currents are generated on the inner surfaces of the upper wall 63 a and the lower wall 63 b of the casing 63 , and the interaction between the eddy currents and the magnetic fields of the permanent magnets 64 causes the flywheel 62 to rotate in the direction opposite to the rotation. Lorentz force is generated. Then, the Lorentz force acts on the flywheel 62 as a resistance (braking force), thereby exerting a damping effect and suppressing the vibration of the structure B.

The abnormality determination device for the damper 51 has basically the same configuration as the abnormality determination device of the first embodiment shown in FIG. consists of

As shown in FIG. 10, in this embodiment, the magnetic sensors 31 are provided on the inner surfaces of the upper wall 63a and the lower wall 63b of the casing 63 in the same number as the permanent magnets 64, and are arranged at regular intervals in the circumferential direction. ing. With this configuration, the magnetic sensor 31 detects the magnetic flux density DM passing through the upper wall 63 a and the lower wall 63 b of the casing 63 and outputs the detection signal to the ECU 30 .

Other configurations of the abnormality determination device of the present embodiment and details of abnormality determination executed by the ECU 30 are the same as those of the first embodiment. Therefore, also in this abnormality determination device, it is possible to obtain the same operations and effects as those of the first embodiment described above.

It should be noted that the present invention is not limited to the described embodiments and can be implemented in various ways. For example, in the abnormality determination process (FIG. 7) of the embodiment, the acceleration generated in the structure B is used as a parameter for determining whether or not an earthquake has occurred. or displacement may be used.

Further, in the second embodiment, as the eddy current damper, a gear motor type damper that converts the flow of the working fluid accompanying the vibration of the structure into the relative rotational motion between the conductive member and the permanent magnet by the gear motor is used. Although used, it is of course possible to use other types of pressure motors instead of gear motors, such as piston motors, vane motors, screw motors, and the like. In both embodiments, the coil 36 is provided in the conductive member (outer cylinder 13, casing 63) in order to detect the induced current generated in the conductive member, but the induced current value IS shown in FIG. The coil 36 can be omitted if the operation state abnormality determination process described above is not executed.

Furthermore, in the embodiment, regarding the display method of the abnormality determination result on the display 41, it is explained that the words meaning "abnormality" or "no abnormality" are displayed as appropriate. good too. For example, in the case of the abnormality determination of the operating state in FIG. As with point B, the operating point (VM, IS) of the rotational speed and current value acquired during the abnormality determination may be plotted.

As a result, when the operating point is located within the region defined by the upper/lower limit current amounts ILMTH and ILMTL, as at point A, the operating state is normal. is located outside the area, it is easy to visually understand that the operating state is abnormal.

Also, the configuration, number, arrangement, and the like of the magnetic sensor 31 and the magnet temperature sensor 32 shown in the embodiment are only examples, and can be changed as appropriate. In addition, it is possible to appropriately change the detailed configuration within the scope of the present invention.

1 Eddy current damper (ball screw damper) of the first embodiment
11a screw shaft 11b ball 12 inner cylinder (nut member)
12a nut portion (nut member)
13 Outer cylinder (conductive member)
14 permanent magnet 30 ECU (first determination means, earthquake occurrence determination means, second determination means)
31 magnetic sensor (magnetic flux density detection means, rotation speed detection means)
32 magnet temperature sensor (temperature detection means)
33 current sensor 34 first acceleration sensor (earthquake occurrence determination means)
35 Second acceleration sensor (earthquake occurrence determination means)
36 coil 41 display (display means)
51 Eddy current type damper of the second embodiment (gear motor type damper)
52 Cylinder 53 Piston 54 Communication Path 55 Gear Motor 63 Casing (Conductive Member)
64 Permanent magnet B Structure DM Magnetic flux density TM Magnet temperature (permanent magnet temperature)
IS current value (induced current generated in the coil)
VM rotation speed of inner cylinder (relative rotation speed between permanent magnet and conductive member)
HF working fluid

Claims (6)

An eddy current type that damps vibration energy by generating eddy currents in conductive members that rotate relatively in the magnetic field of a permanent magnet as the structure vibrates, and using the Lorentz force generated by the eddy currents as a braking force. An abnormality determination device that determines an abnormality of a damper,
magnetic flux density detection means for detecting the magnetic flux density of the magnetic field passed by the conductive member;
a first determination means for determining an abnormality in the magnetic flux density of the magnetic field based on the detected magnetic flux density;
An abnormality determination device for an eddy current damper, comprising: Further comprising temperature detection means for detecting the temperature of the permanent magnet,
2. The vortex according to claim 1, wherein the first determination means determines whether there is a possibility that an abnormality in the magnetic flux density of the magnetic field will occur based on the detected temperature of the permanent magnet. Abnormality determination device for electric dampers. an earthquake occurrence determination means for determining whether an earthquake has occurred;
a current sensor that detects an induced current generated in a coil provided on the conductive member;
rotational speed detection means for detecting a relative rotational speed between the permanent magnet and the conductive member;
a second determination means for determining an abnormality in the operating state of the eddy current damper based on the detected induced current and rotational speed when it is determined that an earthquake has occurred. 3. The eddy current damper abnormality determination device according to claim 1 or 2. 4. An eddy current damper abnormality determination apparatus according to claim 1, further comprising display means for displaying a determination result of abnormality of said eddy current damper. The eddy current damper has a threaded shaft with a thread groove, and a nut member rotatably screwed into the thread groove via a large number of balls,
A ball screw type damper that converts relative displacement between the screw shaft and the nut member due to vibration of the structure into relative rotational motion between the conductive member and the permanent magnet. Item 5. An abnormality determination device for an eddy current damper according to any one of Items 1 to 4. The eddy current damper has a piston slidably provided in a cylinder filled with working fluid, and a gear motor provided in a communication passage communicating with the cylinder,
A gear motor type in which the flow of the working fluid in the communication path generated by the sliding of the piston accompanying the vibration of the structure is converted into relative rotational motion between the conductive member and the permanent magnet by the gear motor. 5. The eddy current damper abnormality determination device according to claim 1, wherein the eddy current damper abnormality determination device is a damper.

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