JP2013185691A - Magnetic floating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent or reduce a change in a relative position of a floating body and a magnetic unit even if a constant external force is generated in a magnetic floating device.SOLUTION: A magnetic floating device 1 includes: a floating body 3, at least part of which is formed with a ferromagnet; magnetic units including at least an electromagnet, disposed facing each other to be partitioned by the floating body 3, and forming a magnetic circuit a magnet resulting from the electromagnet via a gap in the floating body 3; a magnetic support means 2 including a movable frame to which the magnetic units are fixed and a fixed frame supporting a load applied to the movable frame and the floating body 3, and capable of adjusting a distance between the fixed frame and the movable frame; a control means 31 for supporting the floating body 3 in a contactless state by controlling current of the electromagnet based on a relative displacement of the floating body 3 with the magnetic units; an auxiliary magnetic unit including an auxiliary magnet and forming a magnetic circuit resulting from the auxiliary magnet via a gap in the floating body 3; and an eternal auxiliary means 4 where the auxiliary magnetic unit is provided.

Description

  Embodiments of the present invention relate to an apparatus for supporting a levitated body in a non-contact manner by the magnetic force of an electromagnet.

  Magnetic bearings are widely used as means for supporting a rotating body in a non-contact manner. Usually, a magnetic bearing is comprised by the radial bearing which carries out the non-contact support of the movement orthogonal to the rotating shaft of the rotating rotor, and the thrust bearing which carries out the non-contact support of the movement parallel to the rotating shaft. In that case, in order to stably support the rotor, which is a floating body, in a non-contact manner, a normal conducting attraction type magnetic levitation system that controls the attraction force of the electromagnet with respect to either the radial bearing or the thrust bearing is applied. It is common.

  In the normal conducting magnetic levitation system, it is necessary to always form a predetermined attraction force by flowing a bias current through the electromagnet in order to support the levitated body in a non-contact manner. Therefore, power is always consumed regardless of the presence or absence of external force acting on the rotor. Further, since the electromagnet coil is always energized, heat generation is unavoidable, and some cooling means must be taken.

  Further, in a magnetic bearing using a conventional electromagnet, it is necessary to design the gap length between the rotor and the electromagnet to be small in order to obtain a sufficient attractive force with the smallest possible electromagnet. However, when the rotor is rotated in a special environment, for example, in a vacuum, if the entire magnetic bearing is installed in a vacuum, a heat radiation effect cannot be expected, and overheating of the electromagnet may become a problem. Further, when the impeller is rotated as a rotor in a liquid like a can pump, if the entire magnetic bearing is placed in the liquid, the flow of the liquid will be disturbed by the electromagnet, so there is a concern that efficiency will be lowered.

  In such a case, it is conceivable to place the rotor, which is a floating body, inside the vacuum vessel or the pipe so as to be isolated from the electromagnet, and to place the electromagnet outside thereof to support the rotor in a noncontact manner. However, if the electromagnet is arranged outside the container or pipe, the gap length between the rotor and the electromagnet becomes wide, and in order to obtain sufficient electromagnetic force to support the rotor, the electromagnet must be enlarged. There's a problem. It is possible to obtain a large electromagnetic force by increasing the excitation current to the electromagnet. However, in this case, the coil resistance loss of the electromagnet increases, which increases the power consumption of the magnetic bearing and increases the amount of heat generation. There is.

  When performing attraction type magnetic levitation with low power consumption, as described in Patent Document 1, a permanent magnet and an electromagnet constitute a magnet unit, and the main magnetic flux caused by the permanent magnet and the main magnetic flux caused by the electromagnet The magnet unit and the levitation body are arranged so that the magnetic circuit forms a common magnetic path in the gap between the levitation body and the magnet unit, and the excitation current to the electromagnet is reduced to zero while maintaining the stability of the levitation state. There is a method of applying so-called zero power control for convergence. By adopting such a configuration, the magnetic force required to support the floating body in a non-contact manner can be provided by the magnetic force caused by the permanent magnet, and the bias that needs to flow to the electromagnet in order to support the non-contact in a steady manner. No current is required.

  Further, as described in Patent Document 2, even when the relative displacement between the floating body and the magnet unit is large, a large electromagnetic force can be controlled with a small excitation current to the electromagnet.

  In this way, by configuring a magnetic bearing with a magnet unit composed of an electromagnet and a permanent magnet and a floating body and applying zero power control, the rotor can be supported in a non-contact manner with a large gap with low power consumption. . Accordingly, it is possible to support the rotor placed inside a container or pipe made of a non-magnetic material in a non-contact manner from the outside with a magnet unit.

  However, in a general magnetic bearing, the magnet unit generates an electromagnetic force that balances its magnitude against an external force that works constantly. However, when a magnetic bearing is configured by applying zero power control. The magnetic levitation control is performed so that the exciting current to the electromagnet always converges to zero. For this reason, the excitation current converges to zero and the gap length changes, and as a result, it becomes stable at a position where the magnetic levitation can be achieved only by the magnetic force of the permanent magnet. Therefore, when the weight of the rotor or a steady external force acts on the magnetic bearing, the rotation center of the rotor is displaced according to the external force. Displacement of the center of rotation causes, for example, a problem of swirling in a device that rotates at high speed, and in a pump or the like, a fluctuation in efficiency due to the rotational position becomes a problem. In some cases, the rotor may come into contact with a container or a pipe. .

  As a means to solve such a problem, a magnet unit is arranged inside a movable frame supported by an elastic body with respect to a magnetic levitation system to which zero power control is applied, and changes according to the magnitude of an acting external force. A configuration in which changes in relative displacement are mechanically absorbed is conceivable. By setting it as such a structure, the absolute position of a floating body can be maintained in a predetermined position.

JP 61-102105 A Japanese Patent Laid-Open No. 2001-19286

  As described above, by supporting the movable frame with an elastic body, the absolute position of the levitation body can be maintained at a predetermined position, but the relative position between the levitation body and the magnet unit is a magnitude of an external force that constantly acts. It changes according to. This is not a big problem when the steady external force is small, but when the steady external force is large, the steady position of the movable frame is greatly displaced from the neutral position, and the rotor placed inside the container or pipe as described above is moved. In the case of non-contact support from the outside, there is a possibility that the magnet unit may come into contact with the outside of the container or the pipe, and there is a problem that the effective stroke becomes narrow.

  Further, the attractive force acting between the floating body and the magnet unit changes in proportion to the square of the gap between the floating body and the magnet unit. For this reason, when the gap between the levitated body and the magnet unit is significantly changed by a steady external force (for example, gravity), the nonlinearity of the attractive force appears strongly. When the nonlinearity is strong, it is difficult to stabilize the floating body position in the linear control system. In such a case, a control system that takes into account the nonlinear effect must be configured.

  A problem to be solved by an embodiment of the present invention is to provide a magnetic levitation device that does not cause or suppress a change in the relative position between a levitated body and a magnet unit even when a steady external force is applied. It is in.

  The magnetic levitation apparatus according to the embodiment includes a levitation body at least partially formed of a ferromagnetic material, and at least an electromagnet, and is disposed to face the levitation body with the levitation body interposed between the levitation body and a gap. A magnet unit that forms a magnetic circuit of magnetic flux to be generated, a movable frame to which the magnet unit is fixed, and a fixed frame that supports a load applied to the movable frame and the floating body, and the fixed frame and the movable frame A magnetic support means capable of adjusting a distance between the control means, a control means for supporting the floating body in a non-contact manner by controlling a current of the electromagnet based on a relative displacement between the floating body and the magnet unit, and an auxiliary An auxiliary magnet unit that includes a magnet and forms a magnetic circuit of magnetic flux caused by the auxiliary magnet via a gap in the floating body; and an external force assisting means provided with the auxiliary magnet unit. And wherein the door.

  According to the embodiment of the present invention, the magnetic levitation device can prevent or suppress a change in the relative position between the levitated body and the magnet unit even when a steady external force is applied.

It is a side view showing composition of a magnetic levitation device concerning a 1st embodiment. It is a perspective view which shows the structure of the magnetic support unit of FIG. It is a perspective view which shows the structure of the vertical direction support apparatus of FIG. It is a perspective view which shows the structure of the horizontal direction support apparatus of FIG. It is a perspective view which shows the structure of the magnet unit of FIG. 3 and FIG. It is a block diagram which shows the structure of the control apparatus of FIG. It is a figure which shows the support characteristic of the magnetic support unit of FIG. It is a perspective view which shows the structure of the external force compensation apparatus of FIG. FIG. 9 is a perspective view showing the configuration of the auxiliary magnet unit in the first example as the configuration of the auxiliary magnet unit in FIG. 8. FIG. 9 is a perspective view showing a configuration of an auxiliary magnet unit in a second example as the configuration of the auxiliary magnet unit in FIG. 8. FIG. 10 is a perspective view showing a configuration of an auxiliary magnet unit in a third example as the configuration of the auxiliary magnet unit in FIG. 8. FIG. 10 is a perspective view showing a configuration of an auxiliary magnet unit in a fourth example as the configuration of the auxiliary magnet unit in FIG. 8. It is a side view which shows the structure of the magnetic levitation apparatus which concerns on 2nd Embodiment. It is a side view which shows the structure of the magnetic levitation apparatus which concerns on 3rd Embodiment. It is a perspective view of the vertical direction support apparatus with external force compensation of FIG.

  Hereinafter, embodiments of a magnetic levitation apparatus according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a side view showing the configuration of the magnetic levitation apparatus according to the first embodiment.

  The magnetic levitation device 1 includes two magnetic support units 2 (magnetic support means), a levitated body 3, an external force compensation device 4 (external force compensation means), a base 8, and a control device 31 (control means). ing. For example, the two magnetic support units 2 are provided apart from each other on the base 8. The external force compensator 4 is provided between the two magnetic support units 2 on the base 8. The levitation body 3 is an axis extending in the x direction (also referred to as a horizontal direction), and the levitation body 3 is placed on the base 8 at the center of the magnetic support unit 2 (see FIG. 2) and the external force compensator 4 (see FIG. 8). There is a space to pass through. At least a part of the levitated body 3, for example, a part corresponding to the space between the two magnetic support units 2 is formed of a ferromagnetic material. The magnetic levitation device 1 is configured to support the levitation body 3 in a non-contact manner by the magnetic force generated by the magnetic support unit 2 and the external force compensation device 4.

  FIG. 2 is a perspective view showing the configuration of the magnetic support unit 2.

  The magnetic support unit 2 includes a vertical support device 5, a horizontal support device 6, and a position adjusting leg 7. The vertical support device 5 generates a support force in the z direction (direction perpendicular to the x direction (also referred to as the vertical direction)) of the levitated body 3, and the horizontal support device 6 is installed on the position adjustment leg 7. Then, a support force in the y direction (direction orthogonal to the x direction and the z direction (also referred to as the left and right direction)) of the levitated body 3 is generated.

  FIG. 3 is a perspective view showing a configuration of the vertical support device 5.

  The vertical support device 5 includes a vertical fixed frame 9, a vertical movable frame 11, a magnet unit 13, a first gap sensor 14, a second gap sensor 15, a linear guide 16, and a spring 17. It has. Magnet units 13 are respectively fixed to the inner upper portion and the inner lower portion of the vertical movable frame 11. That is, the magnet unit 13 is disposed to face the floating body 3 in the vertical movable frame 11 (see FIG. 2).

  The first gap sensor 14 measures the relative displacement between the levitated body 3 and the magnet unit 13, and the second gap sensor 15 measures the relative displacement between the longitudinal fixed frame 9 and the longitudinal movable frame 11. Is. The dimension of the vertical direction fixed frame 9 is larger than the dimension of the vertical direction movable frame 11, and the vertical direction movable frame 11 is connected to the vertical direction fixed frame 9 via a linear guide 16 and a spring 17. The spring 17 is an elastic element that makes it possible to adjust the distance between the vertical fixed frame 9 and the vertical movable frame 11. Thus, the vertical fixed frame 9 has a structure in which the linear guide 16 and the spring 17 support the load applied to the vertical movable frame 11 and the floating body 3 in the vertical direction.

  FIG. 4 is a perspective view showing the configuration of the lateral support device 6.

  The lateral support device 6 includes a lateral fixed frame 10, a lateral movable frame 12, a magnet unit 13, a first gap sensor 14, a second gap sensor 15, a linear guide 16, and a spring 17. It has. The magnet unit 13, the first gap sensor 14, the second gap sensor 15, the linear guide 16 and the spring 17 of the lateral support device 6 are the same as those of the vertical support device 5, and the longitudinal support device 5 is different in arrangement.

  Magnet units 13 are respectively fixed to the inner left part and the inner right part of the laterally movable frame 12. That is, the magnet unit 13 is disposed opposite to the floating body 3 with the floating body 3 interposed therebetween (see FIG. 2). The first gap sensor 14 measures the relative displacement between the levitated body 3 and the magnet unit 13, and the second gap sensor 15 measures the relative displacement between the lateral fixed frame 10 and the lateral movable frame 12. Is. The dimension of the horizontal direction fixed frame 10 is larger than the dimension of the horizontal direction movable frame 12, and the horizontal direction movable frame 12 is connected to the horizontal direction fixed frame 10 via a linear guide 16 and a spring 17. The spring 17 is an elastic element that makes it possible to adjust the distance between the horizontal fixed frame 10 and the horizontal movable frame 12. As described above, the laterally fixed frame 10 has a structure in which the load applied in the lateral direction to the laterally movable frame 12 and the floating body 3 is supported by the linear guide 16 and the spring 17.

  FIG. 5 is a perspective view showing the configuration of the magnet unit 13.

  The magnet unit 13 includes a permanent magnet 21 and an electromagnet 24 composed of a yoke 22 and a coil 23 wound around the yoke 22. The magnet unit 13 forms a magnetic circuit of magnetic flux caused by the permanent magnet 21 through the gap on the floating body 3 and forms a magnetic circuit of magnetic flux caused by the electromagnet 24 via the gap on the floating body 3. In the magnet unit 13, the direction of the magnetic flux generated by the electromagnet 24 changes according to the direction of the current flowing through the coil 23, and the magnetic flux formed by the permanent magnet 21 can be strengthened or weakened.

  In the vertical support device 5 and the horizontal support device 6, the magnet unit 13 controls the voltage applied to the electromagnet 24 to support the levitated body 3 in a non-contact manner. For this reason, the control device 31 is connected to the coil 23 of the electromagnet 24 of the magnet unit 13 of the longitudinal support device 5 and the coil 23 of the electromagnet 24 of the magnet unit 13 of the lateral support device 6.

  FIG. 6 is a block diagram illustrating a configuration of the control device 31.

  The control device 31 includes a control arithmetic unit 33, a driver 34, and a current sensor 35. The first gap sensor 14, the second gap sensor 15, the coil 23, and the current sensor 35 described above constitute a sensor unit 32.

  In the sensor unit 32, the first gap sensor 14 measures the relative displacement between the floating body 2 and the magnet unit 13 and outputs a signal representing the relative displacement to the control calculator 33. The second gap sensor 15 represents the relative displacement between the fixed frame and the movable frame (in the case of the vertical support device 5, the relative displacement between the vertical fixed frame 9 and the vertical movable frame 11). In this case, the relative displacement between the lateral fixed frame 10 and the lateral movable frame 12 is measured), and a signal representing the relative displacement is output to the control calculator 33. The current sensor 35 detects an excitation current to the coil 23, that is, the electromagnet 24, and outputs a signal representing the excitation current to the control calculator 33.

  In the control arithmetic unit 33, the output of the sensor unit 32 (a signal representing the relative displacement between the levitated body 2 and the magnet unit 13, a signal representing the relative displacement between the fixed frame and the movable frame, and the exciting current to the electromagnet 24) The voltage applied to the coil 23 is calculated based on the signal), and a signal representing the applied voltage is output to the driver 34. The driver 34 applies an applied voltage represented by a signal from the control calculator 33 to the coil 23 to excite the electromagnet 24.

  As described above, the control device 31 controls the magnetic force generated between the magnet unit 13 and the levitated body 3, that is, controls the current of the electromagnet 24 (coil 23). Support by contact.

  The control arithmetic unit 33 is a zero power control system, and has the function of realizing stable levitation of the levitated body 3 and converging the current that constantly flows through the coil 23 to zero based on the output of the sensor unit 32. When a disturbance load due to mass fluctuation of the levitated body 3 or external force fluctuation applied to the levitated body 3 is applied, the relative displacement between the levitated body 3 and the magnet unit 13 changes to a position where all these loads and the magnetic force by the permanent magnet 21 are balanced. It is necessary to flow a current through the electromagnet 24 transiently so that the excitation current to the electromagnet 24 becomes zero by the zero power control when the stable support state is reached. Therefore, all these loads can be stably supported only by the magnetic force of the permanent magnet 21.

  FIG. 7 is a diagram showing the support characteristics of the magnetic support unit 2.

  When the vertical movable frame 11 and the horizontal movable frame 12 are connected to the vertical fixed frame 9 and the horizontal fixed frame 10 via the linear guide 16 and the spring 17, respectively, the floating body 3 is stably controlled by zero power control. When non-contact support is performed, the relationship shown in FIG. 7 is established. That is, the relative displacement between the levitated body 2 and the magnet unit 13 changes so that the magnetic force of the permanent magnet 21 and the total weight of the levitated body 2 and the acting disturbance load are balanced by zero power control. Further, the spring 17 having a displacement-restoring force characteristic equivalent to the displacement-attraction force characteristic due to the magnetic force is combined with a spring support characteristic having an inclination opposite to the magnetic support characteristic, resulting in a composite support in the figure. It becomes load-displacement characteristics like characteristics, and fluctuations in the absolute position of the levitated body 3 are greatly reduced.

  Therefore, by arranging the magnetic support units 2 at two locations as shown in FIG. 1, even when a steady external force is generated on the levitated body, the centroid position in the y direction, the centroid position in the z direction, y Variations in the posture angle around the axis and the posture angle around the z-axis can be reduced.

  However, the gap between the levitated body 3 and the magnet unit 13 varies. For example, when only gravity acts constantly, the gap between the magnet unit 13 of the vertical support device 5 and the floating body 3 varies, and as a result, the vertical fixing frame 9 is displaced upward. As a result, there arises a problem due to the contact between the vertical movable frame 15 and peripheral parts (not shown) and the non-linear effect of the suction force as described above.

  The external force compensator 4 shown in FIG. 1 functions to solve these problems.

  FIG. 8 is a perspective view showing the configuration of the external force compensator 4.

  The external force compensation device 4 includes a frame 41, a horizontal adjustment mechanism 42, and a vertical adjustment mechanism 43.

  The horizontal adjustment mechanism 42 includes a horizontal linear guide 44 and a horizontal feed screw 45. The horizontal linear guide 44 and the horizontal feed screw 45 are provided on the base 8 shown in FIG. 1, and a frame 41 is connected to a part of the horizontal linear guide 44.

  The horizontal adjustment mechanism 42 can adjust the relative position in the horizontal direction with respect to the floating body 3. Specifically, the horizontal adjustment mechanism 42 can adjust the horizontal position of the frame 41 whose movement is guided in the horizontal direction (x-axis direction) by the horizontal linear guide 44 by turning the horizontal feed screw 45. ing.

  The vertical adjustment mechanism 43 includes a vertical linear guide 46, a vertical feed screw 47, and an auxiliary magnet unit 48. The auxiliary magnet unit 48 is connected to the inner upper portion of the frame 41 via a vertical linear guide 46 and a vertical feed screw 47. The auxiliary magnet unit 48 includes an auxiliary permanent magnet, and forms a magnetic circuit of magnetic flux caused by the auxiliary permanent magnet of the auxiliary magnet unit 48 through the air gap in the floating body 3. The configuration of the auxiliary magnet unit 48 and the structure of the auxiliary permanent magnet will be described later.

  The vertical adjustment mechanism 43 can adjust the relative position between the auxiliary magnet unit 48 and the floating body 3. Specifically, the vertical adjustment mechanism 43 can change the vertical position of the auxiliary magnet unit 48 whose movement is guided in the vertical direction (z-axis direction) by the vertical linear guide 46 by turning the vertical feed screw 47. The gap between the floating body 3 and the auxiliary magnet unit 48 can be adjusted.

  First, the operation of the horizontal adjustment mechanism 42 will be described.

  The horizontal adjustment mechanism 42 can move its position in the horizontal direction (x-axis direction) by the horizontal linear guide 44 and the horizontal feed screw 45 and can adjust the distance between itself and the magnetic support unit 2. Thereby, the horizontal adjustment mechanism 42 can be adjusted so that the line of action of the magnetic force acting between the floating body 3 and the auxiliary magnet unit 48 is matched to the vicinity of the center of gravity of the floating body 3.

  For example, in the horizontal adjustment mechanism 42, the moment acting on the levitated body 3 due to the magnetic flux caused by the auxiliary permanent magnet of the auxiliary magnet unit 48 cancels out the moment around the y axis generated in the levitated body 3 due to gravity. As described above, by adjusting the horizontal position of the horizontal adjustment mechanism 42, fluctuations in the posture angle can be suppressed.

  Next, the operation of the vertical adjustment mechanism 43 will be described.

  Further, the vertical adjustment mechanism 43 cancels out the resultant force of the steady external force other than the resultant force of the magnetic force acting on the levitated body 3 by the resultant force of the magnetic force generated in the levitated body 3 by the magnetic flux caused by the auxiliary permanent magnet of the auxiliary magnet unit 48. As described above, by adjusting the vertical position of the auxiliary magnet unit 48, it is possible to suppress fluctuations in the position of the movable frame caused by the resultant force of the steady external force.

  For example, when only gravity acts on the levitated body 3 steadily, the vertical adjustment mechanism 43 sets the vertical position of the auxiliary magnet unit 48 so that the magnetic force acting between the levitated body 3 and the auxiliary magnet unit 48 is balanced with the gravity. By adjusting, fluctuations in the position of the movable frame caused by gravity can be suppressed. Here, an example in which only gravity is constantly acting on the levitated body 3 has been shown, but even when a steady external force acts in other directions, the auxiliary magnet unit is on the line of action of the resultant force of the steady external force. The same effect can be obtained by changing the mounting position of 48.

  FIG. 8 shows an example of the shape and configuration of the auxiliary magnet unit 48. However, if the auxiliary magnet unit 48 includes a permanent magnet in a part thereof and can generate a steady magnetic force, the shape and configuration are limited. At least the same effect can be obtained.

  FIG. 9 is a perspective view showing the configuration of the auxiliary magnet unit 48 in the first example as the configuration of the auxiliary magnet unit 48.

  The auxiliary magnet unit 48 in the first example includes one auxiliary permanent magnet 50 and one yoke 51 to which the auxiliary permanent magnet 50 is attached, and the floating body 3 is formed by the auxiliary permanent magnet 50 and the yoke 51. Generates a steady magnetic force. Although the shape is different from the auxiliary magnet unit 48 shown in FIG. 8, the same effect as the auxiliary magnet unit 48 shown in FIG. 8 can be obtained.

  FIG. 10 is a perspective view showing the configuration of the auxiliary magnet unit 48 in the second example as the configuration of the auxiliary magnet unit 48.

  The auxiliary magnet unit 48 in the second example includes one auxiliary permanent magnet 50 and two yokes 51 to which the auxiliary permanent magnet 50 is attached. The auxiliary permanent magnet 50 and the yoke 51 are levitated. A steady magnetic force is generated on the body 3. The surface of the yoke 51 that faces the floating body 3 is formed in a shape that follows the shape of the floating body 3. Thereby, in the magnetic circuit formed between the auxiliary magnet unit 48 and the levitated body 3 through the air gap, the magnetic resistance is lowered, so that the leakage magnetic flux is reduced. As a result, effects of leakage magnetic flux on peripheral parts not shown in the figure are suppressed, and an effect of increasing the magnetic force acting between the auxiliary magnet unit 48 and the floating body 3 is obtained.

  FIG. 11 is a perspective view showing the configuration of the auxiliary magnet unit 48 in the third example as the configuration of the auxiliary magnet unit 48.

  The auxiliary magnet unit 48 in the third example includes one auxiliary permanent magnet 50 and two yokes 51 to which the auxiliary permanent magnet 50 is attached and made of laminated steel plates. The yoke 51 generates a steady magnetic force on the levitated body 3. Furthermore, in the auxiliary magnet unit 48 in the third example, the surface of the yoke facing the levitated body 3 is formed in a shape that follows the shape of the levitated body 3. Thereby, while suppressing the influence of the leakage magnetic flux to the peripheral parts which are not shown in a figure, the effect that the magnetic force which acts between the auxiliary magnet unit 48 and the floating body 3 increases is acquired.

  Further, when the levitated body 3 is a rotating body, the levitation body 3 is provided with a magnetic target made of a laminated steel plate at a portion facing the auxiliary magnet unit 48, thereby suppressing eddy current loss caused by the rotation of the levitated body 3. can do.

  When the floating body 3 is a rotating body, the magnet unit 13 of the lateral support device 6 is a pair of y-axis magnet units that sandwich the floating body 3 from the y direction perpendicular to the rotation axis of the floating body 3. The magnet unit 13 of the direction support device 5 is a pair of z-axis magnet units that sandwich the levitated body 3 from the z direction perpendicular to the rotation axis and the y direction. In this case, in the lateral support device 6 shown in FIG. 4, the lateral movable frame 12 is a y-axis movable frame that fixes the y-axis magnet unit (magnet unit 13), and the lateral fixed frame 10 is movable in the y-axis. This is a y-axis fixed frame that supports the frame (laterally movable frame 12). Further, in the vertical support device 5 shown in FIG. 3, the vertical movable frame 11 is a z-axis movable frame that fixes the z-axis magnet unit (magnet unit 13), and the vertical fixed frame 9 is the z-axis movable frame. It becomes a z-axis fixed frame that supports the (vertical movable frame 11).

  Further, the horizontal adjustment mechanism 42 of the external force compensator 4 shown in FIG. 8 is a rotation axis direction adjustment mechanism that can adjust the relative position of the auxiliary magnet unit 48 and the floating body 3 with respect to the rotation axis direction of the floating body 3. The vertical adjustment mechanism 43 is a radial adjustment mechanism that can adjust the relative position of the auxiliary magnet unit 48 and the floating body 3 with respect to the radial direction of the floating body 3.

  FIG. 12 is a perspective view showing the configuration of the auxiliary magnet unit 48 in the fourth example as the configuration of the auxiliary magnet unit 48.

  The auxiliary magnet unit 48 in the fourth example includes five auxiliary permanent magnets 50 arranged in a Halbach array and a holder 53 to which the auxiliary permanent magnet 50 is attached. Generates a steady magnetic force. Because the Halbach array concentrates most of the magnetic flux due to the auxiliary permanent magnet 50 on the floating body 3 side, the influence of leakage magnetic flux on peripheral parts not shown in the figure is suppressed, and the auxiliary magnet unit 48 and the floating body 3 The effect of increasing the magnetic force acting between the two is obtained.

  As described above, the magnetic levitation apparatus 1 can prevent or suppress a change in the relative position between the levitation body 3 and the magnet unit 13 even when a steady external force is applied.

(Second Embodiment)
Regarding the magnetic levitation apparatus according to the second embodiment, only the changes from the first embodiment will be described. Portions that are not particularly described are the same as those in the first embodiment.

  FIG. 13 is a side view showing the configuration of the magnetic levitation apparatus according to the second embodiment.

  The magnetic levitation device 1 includes two magnetic support units 2, a levitation body 3, two external force compensation devices 4, a base 8, and a control device 31. That is, two external force compensators 4 are provided in the configuration of the first embodiment. The vertical adjustment mechanisms 43 of the two external force assisting devices 4 can independently adjust the relative positions of the auxiliary magnet unit 48 and the floating body 3.

  In the first embodiment, the line of action of the magnetic force acting between the levitated body 3 and the auxiliary magnet unit 48 is positioned near the center of gravity of the levitated body 3, so that the around the y axis generated in the levitated body 3 due to gravity. Although an action that cancels the moment is obtained, depending on the arrangement of peripheral parts not shown in the figure, the line of action of the magnetic force acting between the levitated body 3 and the auxiliary magnet unit 48 is positioned near the center of gravity of the levitated body 3. It may be difficult to do.

  In the second embodiment, the distance between the two external force compensators 4 is adjusted without positioning the line of magnetic force acting between the levitated body 3 and the auxiliary magnet unit 48 in the vicinity of the center of gravity of the levitated body 3. Thus, an effect is obtained in which moments around the y-axis generated in the levitated body 3 due to gravity are offset.

  Further, other effects shown in the first embodiment can be obtained in the same manner.

(Third embodiment)
Regarding the magnetic levitation apparatus according to the third embodiment, only the changes from the first embodiment will be described. Portions that are not particularly described are the same as those in the first embodiment.

  FIG. 14 is a side view showing the configuration of the magnetic levitation apparatus according to the third embodiment.

  The magnetic levitation apparatus 1 includes two magnetic support units 60 with external force compensation, a levitation body 3, a base 8, and a control device 31. The magnetic support unit 60 with external force compensation includes a lateral support device 6, a position adjusting leg 7, and a vertical support device 61 with external force compensation.

  FIG. 15 is a perspective view showing the configuration of the longitudinal support device 61 with external force compensation. The vertical support device 61 with external force compensation is different from the vertical fixing frame 9 in the first embodiment in the vertical adjustment mechanism 43 (the vertical linear guide 46, the vertical feed screw 47, and the auxiliary magnet unit 48 in the first embodiment). ) Is attached. That is, the vertical support device 5 and the external force compensation device 4 are integrated.

  The two vertical adjustment mechanisms 43 incorporated in the magnetic support unit 60 with external force compensation are respectively adjusted, and the relative positions in the vertical direction of the two auxiliary magnet units 48 are changed to cause the floating body 3 due to gravity. An effect is obtained in which moments around the y axis are canceled out. Further, the floating bodies 3 and 2 are adjusted by adjusting the two vertical adjustment mechanisms 43 and changing the absolute positions of the two auxiliary magnet units 48 while maintaining the relative positions of the two auxiliary magnet units 48 in the vertical direction. The two auxiliary magnet units 48 can be moved to a position where the sum of the magnetic forces acting between the two auxiliary magnet units 48 is balanced with the gravity, or in the vicinity thereof. Thereby, the fluctuation | variation of the movable frame position which arises by gravity can be suppressed.

  Further, other effects shown in the first embodiment can be obtained in the same manner.

(Other embodiments)
As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, modifications, and features of the embodiments can be combined without departing from the spirit of the invention. . These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Magnetic levitation apparatus 2 ... Magnetic support unit 3 ... Levitation body 4 ... External force compensation apparatus 5 ... Vertical support apparatus 6 ... Lateral support apparatus 7 ... Position adjustment leg 8 ... Base 9 ... Vertical direction fixed frame 10 ... Horizontal direction fixation Frame 11 ... Vertical movable frame 12 ... Horizontal movable frame 13 ... Magnet unit 14 ... First gap sensor 15 ... Second gap sensor 16 ... Linear guide 17 ... Spring 21 ... Permanent magnet 22 ... Relay 23 ... Coil 24 ... Electromagnet 31 ... Control device 32 ... Sensor unit 33 ... Control calculator 34 ... Driver 35 ... Current sensor 41 ... Frame 42 ... Horizontal adjustment mechanism 43 ... Vertical adjustment mechanism 44 ... Horizontal linear guide 45 ... Horizontal feed screw 46 ... Vertical linear guide 47… Vertical feed screw 48… Auxiliary magnet unit
50 ... auxiliary permanent magnet 51 ... yoke 60 ... magnetic support unit with external force compensation 61 ... longitudinal support device with external force compensation

Claims (15)

A levitated body at least partially formed of a ferromagnetic material;
A magnet unit that includes at least an electromagnet and is opposed to the levitating body, and forms a magnetic circuit of magnetic flux caused by the electromagnet through the gap on the levitating body;
A magnetic support means comprising: a movable frame to which the magnet unit is fixed; a fixed frame for supporting a load applied to the movable frame and the floating body; and a magnetic support means capable of adjusting a distance between the fixed frame and the movable frame;
Control means for supporting the floating body in a non-contact manner by controlling the current of the electromagnet based on the relative displacement between the floating body and the magnet unit;
An auxiliary magnet unit that includes an auxiliary magnet and forms a magnetic circuit of magnetic flux caused by the auxiliary magnet through a gap in the floating body;
An external force assisting means provided with the auxiliary magnet unit;
A magnetic levitation apparatus comprising:   The external force assisting means is located at a position where the resultant magnetic force generated on the levitating body by the magnetic flux caused by the auxiliary magnet cancels out the resultant resultant external force other than the resultant magnetic force acting on the levitating body. The magnetic levitation apparatus according to claim 1, further comprising a mechanism for arranging the auxiliary magnet unit.   The external force assisting means includes a mechanism for disposing the auxiliary magnet unit at a position where a moment acting on the levitating body and a moment generated due to gravity are offset by a magnetic flux due to the auxiliary magnet. The magnetic levitation apparatus according to claim 1, wherein the magnetic levitation apparatus is a magnetic levitation apparatus.   4. The magnetic levitation apparatus according to claim 1, wherein the external force assisting unit includes a mechanism capable of adjusting a relative position between the auxiliary magnet unit and the levitating body. 5. .   The external force assisting means is provided in a plurality, and the plurality of external force assisting means includes a mechanism capable of independently adjusting the relative positions of the auxiliary magnet unit and the floating body. The magnetic levitation apparatus according to claim 3.   6. The control means according to claim 1, further comprising means for measuring an excitation current to the electromagnet and a means for converging the excitation current to the electromagnet to zero. The magnetic levitation device according to one item.   The magnetic levitation according to any one of claims 1 to 6, wherein the magnetic support means includes an elastic element capable of adjusting a distance between the fixed frame and the movable frame. apparatus. The floating body is a rotating body,
The magnet unit includes a pair of y-axis magnet units that sandwich the levitating body from the y direction perpendicular to the rotation axis of the levitating body and a pair of z that sandwich the levitating body from the z direction orthogonal to the rotation axis and the y direction. A shaft magnet unit,
The movable frame of the magnetic support means includes a y-axis movable frame that fixes the y-axis magnet unit, and a z-axis movable frame that fixes the z-axis magnet unit.
The said fixed frame of the said magnetic support means has a y-axis fixed frame which supports the said y-axis movable frame, and a z-axis fixed frame which supports the said z-axis movable frame. The magnetic levitation apparatus according to any one of claims 7 to 9.   The external force assisting means includes a rotation axis direction adjusting mechanism capable of adjusting a relative position between the auxiliary magnet unit and the floating body with respect to a rotation axis direction of the floating body. The magnetic levitation apparatus according to 8.   The external force assisting means includes a radial direction adjustment mechanism capable of adjusting a relative position between the auxiliary magnet unit and the levitating body with respect to a radial direction of the levitating body. The magnetic levitation device according to claim 9.   The magnetic levitation apparatus according to claim 10, wherein the adjustment by the rotation axis direction adjustment mechanism and the adjustment by the radial direction adjustment mechanism are performed independently.   The auxiliary magnet unit further includes a yoke, and the auxiliary permanent magnet, which is the auxiliary magnet, and the yoke generate a steady magnetic force with respect to the floating body. The magnetic levitation device according to claim 11.   13. The magnetic levitation apparatus according to claim 12, wherein a surface of the yoke facing the levitation body is formed in a shape that follows the shape of the levitation body.   The magnetic levitation apparatus according to claim 11, wherein the yoke is formed of a laminated steel plate.   The magnetic levitation apparatus according to any one of claims 1 to 11, wherein auxiliary permanent magnets as the auxiliary magnets are arranged in a Halbach array.

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