JP7366842B2 - Electromagnetic suspension and washing machine - Google Patents

Description

The present invention relates to an electromagnetic suspension and a washing machine.

Linear motors and linear actuators (hereinafter collectively referred to as linear motors) are known as electric machines that perform linear motion. A linear motor has a structure in which a rotating machine is cut into a straight line, and generates thrust in the movable element by magnetic force acting between magnetic poles formed on each of the stator and the movable element. The difference from a rotary motor is that in a rotary motor, the stator and mover can oppose each other in an endless track, whereas in a linear motor, the stroke length is determined according to the number of arranged magnets. In order to increase the stroke length, it is possible to increase the number of magnets, increase the size of the magnets, etc., but both of these methods increase cost.

Patent Document 1 describes a vibration damping device using a linear actuator having a vibration sensor. Further, Patent Document 2 discloses a technique for suppressing vibration by arranging an electromagnetic suspension in a washing machine. Further, Patent Document 3 describes a technique using a single-phase linear actuator in a suspension device of a vehicle such as an automobile or a railway vehicle.

JP2012-241773A Japanese Patent Application Publication No. 2010-78075 JP2011-166880A

When an electromagnetic suspension is used in a vibration damping device, a phenomenon occurs in which the electromagnetic suspension sinks due to the weight of the mover or the gravitational energy of the object to be damped. In this case, the designer needs to avoid the problem by, for example, giving a margin to the stroke length so that the positioning of the stator and mover of the electromagnetic suspension will not be lost due to disturbance factors caused by the fastening to the damping object. However, there was a problem in that the mover and stator were made larger and the cost increased. Alternatively, the problem has been avoided by applying an expensive and powerful magnet that is not affected by disturbance factors.

Patent Document 1 discloses that when a movable element continuously collides with a mechanical stopper in a vibration damping device, in order to reduce the occurrence of abnormal noise and malfunction of the mechanical stopper, the movable element is moved in a state where excessive vibration is applied based on information from a vibration sensor. A technique for pressing a child in the direction of gravity has been disclosed. However, the relationship between the amount of magnets and the stroke length is not shown.

Patent Document 2 describes a technique in which an electromagnetic suspension equipped with a position sensor is arranged as a suspension for a washing machine, and vibrations are suppressed by vector control.

Patent Document 3 describes a technique for suppressing a decrease in thrust in a single-phase linear actuator by increasing the coil pitch and the magnetic pole pitch.

However, none of the patent documents describes the positioning of a linear motor using the gravitational energy of the object to be damped, or the relationship between the thrust of the linear motor and the gravitational energy of the object to be damped. Furthermore, there is no idea of utilizing the gravitational energy of the object to be damped for positioning the electromagnetic suspension.

The present invention has been made in order to solve the above-mentioned problems, and uses the gravitational energy of a vibration damping object connected to an electromagnetic suspension to position the stator and mover of the electromagnetic suspension, thereby achieving a compact and low-cost device. The purpose is to provide an electromagnetic suspension and a washing machine.

In order to achieve the above object, an electromagnetic suspension of the present invention is provided, in which the electromagnetic suspension is connected to an object to be damped, the electromagnetic suspension is disposed in a vertical direction or inclined from the vertical direction, and the electromagnetic suspension has a stator, A linear motor has at least two magnets located at a position facing the stator, a movable element that moves relative to the stator, and an elastic body that pushes the movable element upward. Assuming that the center is V ₀ , when the electromagnetic suspension is not connected to the object to be damped, V ₀ is arranged offset from the center of the magnetic poles of the stator in the anti-gravity direction. Other aspects of the present invention will be explained in the embodiments described below.

According to the present invention, it is possible to realize a compact and low-cost electromagnetic suspension.

FIG. 1 is a cross-sectional perspective view of the electromagnetic suspension according to the first embodiment. FIG. 3 is a perspective view of a movable element and a support mechanism section according to the first embodiment. FIG. 3 is a perspective cross-sectional view of the linear motor section according to the first embodiment. FIG. 2 is a schematic cross-sectional view taken along line II in FIG. 1; It is an exploded perspective view of the mover in a 1st embodiment. FIG. 3 is an explanatory diagram of the operation of the linear motor in the first position according to the first embodiment. FIG. 6 is an explanatory diagram of the operation of the linear motor in the second position according to the first embodiment. FIG. 7 is an explanatory diagram of the operation of the linear motor in the third position according to the first embodiment. FIG. 1 is a core assembly diagram and a schematic diagram of a winding method of a linear motor according to a first embodiment. FIG. 3 is a cross-sectional perspective view of an electromagnetic suspension according to a comparative example. FIG. 7 is a perspective view of an electromagnetic suspension and a washing machine according to a second embodiment. FIG. 3 is a perspective view of a washing machine according to a third embodiment. It is a longitudinal cross-sectional view of a washing machine according to a third embodiment. It is a block diagram of the vibration damping device applied to 3rd Embodiment. FIG. 7 is a configuration diagram of main parts of a vibration damping device applied to a third embodiment. These are experimental results showing changes in the rotational speed of the washing tub and the displacement (vibration) of the outer tub in a comparative example using an oil damper (hydraulic damper) with a constant viscous damping coefficient C. In another control example of the third embodiment, the electromagnetic suspension of the comparative example shown in FIG. 8 is used to show experimental results showing changes in the rotational speed of the washing tub and the displacement (vibration) of the outer tub. In another control example of the third embodiment, the electromagnetic suspension of the present embodiment shown in FIG. 1 is used to show experimental results showing changes in the rotational speed of the washing tub and the displacement (vibration) of the outer tub. FIG. 6 is a diagram illustrating an excerpt of the cores of a mover and a stator in Modification Example 1 of the electromagnetic suspension according to the first embodiment. FIG. 6 is a diagram illustrating an excerpt of the cores of the mover and stator in Modification Example 2 of the electromagnetic suspension according to the first embodiment. It is a perspective view which extracted and showed the frame and magnet of the mover in the modification 3 of the electromagnetic suspension based on 1st Embodiment. It is a perspective view which extracted and showed the frame and magnet of the mover in the modification 4 of the electromagnetic suspension based on 1st Embodiment.

Embodiments for implementing the present invention will be described in detail with reference to the drawings as appropriate.
[First embodiment]
<Configuration of first embodiment>
FIG. 1 is a cross-sectional perspective view of an electromagnetic suspension 100 according to a first embodiment. Note that the electromagnetic suspension 100 is applied, for example, to suppress vibrations of a washing machine W (see FIG. 10). The electromagnetic suspension 100 in FIG. 1 is not connected to the vibration damping object Dt (see FIG. 9).

FIG. 1 is a cross-sectional perspective view of an electromagnetic suspension 100 according to a first embodiment. As shown by symbols x, y, and z in FIG. 1, the x-axis, y-axis, and z-axis are defined (the z-axis is in the vertical direction). FIG. 1 shows an overview of the external appearance of the electromagnetic suspension 100, and also shows the internal structure of the electromagnetic suspension 100 by cutting a quarter thereof. The electromagnetic suspension 100 includes a linear motor 10.

The electromagnetic suspension 100 includes a pair of opposing shafts 21 that connect frames (for example, shaft fixing fittings 23), a stator 11 having an armature core and an armature winding, and a stator 11 fixed between the frames. It has a magnet or a magnetic body having a first surface (for example, the front surface 122f in FIG. 5) and a second surface (for example, the back surface 122r in FIG. 5) facing the stator 11, and is movable relative to the stator 11. The linear motor 10 has a movable element 12, and an elastic body 20 that is attached to a shaft and is compressed between one of the frames and an arm (bearing 22) of the stator 11.

There are two shafts 21 and two elastic bodies 20 at positions parallel to the movable element 12 of the linear motor 10 and the propulsion direction (z-axis direction in the figure). The shaft 21 passes through the elastic body 20. Further, the shaft 21 slides in the moving direction of the movable element 12 via the stator 11 of the linear motor 10 and the bearing 22. In this embodiment, a sliding bearing whose metal surface is lubricated is used as the bearing 22.

The center of vibration (in this figure, the magnetic center of the mover is also the same) is V ₀ and is indicated by a broken line. The magnetic center of the stator is designated as A ₀ and is indicated by a dashed line. In FIG. 1, the center of vibration V ₀ projects further in the anti-gravity direction than the magnetic center A ₀ of the stator. It is the elastic body 20 that pushes up the center of vibration V ₀ in the anti-gravity direction. In this case, it is a rolled metal spring, and the spring is in an extended state. In other words, if a force greater than the spring force is applied to the movable element 12, the movable element 12 sinks into the stator 11.

FIG. 2 is a perspective view of a support mechanism section including the movable element 12 according to the first embodiment. The movable member 12 is disposed within a support mechanism portion having a mouth-shaped structure that includes a shaft fixing fitting 23 and a pair of opposing shafts 21 that connect the shaft fixing fittings 23. In other words, it forms a wider and thicker surface structure than the movable element 12 alone.

FIG. 3 is a perspective sectional view of the linear motor 10 according to the first embodiment. FIG. 3 shows an overhead view of the external appearance of the linear motor 10, and also shows the internal structure by cutting a quarter of it. The linear motor 10 includes a stator 11 that is an armature, and a plate-shaped movable element 12 that extends in the z-axis direction.

The stator 11 is formed into a substantially prismatic shape along the z-axis direction, and a rectangular plate-shaped movable element 12 is loosely inserted into a hollow portion of the stator 11 . Then, the linear motor 10 changes the relative position between the stator 11 and the movable element 12 in the z-axis direction by the magnetic attraction/repulsion force, that is, the thrust force acting between the stator 11 and the movable element 12. . When applying the linear motor 10 to the electromagnetic suspension 100, the movable element 12 is coupled to the vibration damping object Dt (see FIG. 9). In the example shown in FIG. 1, the outer tub 37 (see FIG. 10) of the washing machine W is the vibration damping object Dt, and the stator 11 or the movable element 12 is coupled to the outer tub 37.

The stator 11 includes a core 11a (armature core) and a winding 11b (armature winding). The core 11a is made by laminating electromagnetic steel sheets in the z-axis direction, and includes magnetic teeth 151 (first magnetic teeth) adjacent to each other along the z-axis direction and protruding toward the movable element 12. Further, the core 11a includes magnetic teeth 152 (second magnetic teeth) adjacent to the magnetic tooth 151 along the z-axis direction and protruding toward the movable element 12, at a position opposite to the magnetic tooth 151 with the movable element 12 in between. We are prepared.

The winding 11b is wound around these magnetic teeth 151 and 152. Further, the movable element 12 includes a frame 122 made of a non-magnetic material and magnets 124 (magnets 124a, 124b) fitted into the frame 122.

FIG. 4 is a schematic cross-sectional view taken along line II in FIG. 3. However, the 1/4 portion cut in FIG. 1 is not cut in FIG. 4. As shown in FIG. 4, the core 11a of the stator 11 includes an annular portion 156 and magnetic teeth 151, 152.

The annular portion 156 has an annular shape, that is, a substantially rectangular frame shape in a longitudinal cross-sectional view, and the annular portion 156 constitutes a magnetic circuit. The pair of magnetic teeth 151 and 152 extend inward from the annular portion 156 along the y-axis direction and are opposed to each other. In other words, two gaps exist in the magnetic path of the motor characteristic of the present invention.

A magnetic flux ΦA indicated by a solid arrow is a magnetic flux generated by the movable element 12. A winding 11b is wound around each of the magnetic teeth 151, 152. An inverter (for example, an inverter 40 in FIG. 12 described later) is connected to the winding 11b. When the winding 11b is energized by this inverter, the stator 11 functions as an electromagnet.

FIG. 5 is an exploded perspective view of the mover 12 in the first embodiment. As shown in FIG. 3, the movable element 12 includes a frame 122 and two magnets 124a and 124b. The frame 122 is a rectangular frame made of non-magnetic material. A rectangular through hole 122h is formed in the frame 122, passing through the front surface 122f (first surface) and the back surface 122r (second surface).

Moreover, in order to improve the responsiveness of the linear motor 10, it is desirable that the mover 12 is lightweight. Therefore, it is conceivable to use a lightweight material such as plastic or aluminum as the non-magnetic material constituting the frame 122. Furthermore, a lightweight and high-strength composite material such as carbon fiber reinforced plastic may be used. That is, the material of the frame 122 may be arbitrarily selected depending on the required strength and specifications of the linear motor 10.

Further, the two magnets 124a and 124b are arranged alternately so that their magnetic poles are reversed in the y-axis direction. When the magnet 124 is fitted into the frame 122, on the surface 122f side (the upper surface in FIG. 5) of the through hole 122h, the magnet 124a has an N pole and the magnet 124b has an S pole. Further, from the rear surface 122r side (bottom surface in FIG. 5) of the through hole 122h, the magnet 124a is an S pole, and the magnet 124b is an N pole.

Next, the operation of the linear motor 10 will be explained.
6A, 6B, and 6C are explanatory diagrams of the operation of the linear motor 10 according to the first embodiment. In FIG. 1, the downward direction of the page is taken as the direction of gravity, but in FIG. 6, the right direction of the page is shown as the direction of gravity. FIG. 6A is an explanatory diagram of the operation of the linear motor 10 in the first position (state P1) according to the first embodiment. FIG. 6B is an explanatory diagram of the operation of the linear motor 10 in the second position (state P2) according to the first embodiment. FIG. 6C is an explanatory diagram of the operation of the linear motor 10 in the third position (state P3) according to the first embodiment.

As described above, the stator 11 includes the core 11a (armature core) and the winding 11b (armature winding). The core 11a includes a core back portion 11a1, a tooth portion 11a2, and a tooth stop portion 11a3, which is an end face of the tooth portion 11a2 facing the magnet.

State P1 (first position), state P2 (second position), and state P3 (third position) shown in FIGS. 6A, 6B, and 6C are the relative positions of stator 11 and mover 12. The positional relationships are different. In addition, in FIGS. 6A, 6B, and 6C, solid thick arrows indicate the direction of the magnetic flux generated by the magnet 124, and broken line thick arrows indicate the direction of the magnetic flux generated by the stator 11. . In any of the states P1 to P3, the magnetic teeth 151 face the front surface 122f of the frame 122, and the magnetic teeth 152 face the back surface 122r of the frame 122.

In state P1 of FIG. 6A, the winding 11b is not energized, so the stator 11 does not generate magnetic flux. The center of the stator 11 (no reference numeral) in the z-axis direction matches the center of the movable element 12 (no reference numeral). Furthermore, when a current is passed through the winding 11b, the magnetic teeth 151 and 152 can be magnetized depending on the direction of the current. In state P1, when the magnetic tooth 151 is magnetized to the north pole and the magnetic tooth 152 is magnetized to the south pole, the magnet 124a becomes the magnetic tooth 151, similar to the symbols "N" and "S" shown in state P2. , 152, and the magnet 124a is attracted to the magnetic teeth 151, 152.

In this way, due to the attraction and repulsion forces acting between the stator 11 and the movable element 12, a thrust force is applied to the stator 11 and the movable element 12 relative to each other along the z-axis direction. Note that "thrust" is a force that changes the relative position between the movable element 12 and the stator 11. Therefore, as shown in state P2, for example, the movable element 12 is urged and moved relative to the stator 11 in the positive direction of the z-axis (leftward in FIG. 6B).

Conversely, in state P1, when the magnetic tooth 151 is magnetized to the S pole and the magnetic tooth 152 is magnetized to the N pole, the magnet 124a becomes The magnet 124b is repelled by the magnetic teeth 151 and 152, and the magnet 124b is repelled by the magnetic tooth 151 and attracted to the magnetic tooth 152. Therefore, as shown in state P3, for example, the movable element 12 is urged and moved relative to the stator 11 in the negative direction of the z-axis (rightward in the figure). Note that the length of the regular range, which is the movement range of the movable element 12 from state P2 to state P3, is indicated by "common range length UL (range length)."

FIG. 7 is a schematic diagram illustrating the assembly and winding method of the core 11a of the linear motor 10 according to the embodiment. When molding the core 11a of the linear motor 10, the core back portion 11a1 and the teeth portion 11a2 are integrally press-molded from electromagnetic steel sheets in the xy plane and laminated in the z-axis direction to obtain the core 11a. Next, the pre-processed winding 11b is fitted into the teeth portion 11a2. Thereafter, two cores 11a each having a winding 11b are prepared in the same manner and are combined vertically (in the y-axis direction in the figure) to obtain magnetic teeth 151 to 152.

FIG. 8 is a cross-sectional perspective view of an electromagnetic suspension 100C of a comparative example. The electromagnetic suspension 100C of the comparative example in FIG. 8 is not connected to the vibration damping object Dt (see FIG. 9). FIG. 8 shows an overhead view of the external appearance of the electromagnetic suspension 100C of the comparative example, and also shows the internal structure by cutting 1/4 of it. Similar to the electromagnetic suspension 100 of the present invention, the electromagnetic suspension 100C of the comparative example includes a pair of opposing shafts 21 connecting frames 23 (shaft fixing fittings), and a stator 11 having an armature core and an armature winding. and a magnet or magnetic body fixed between the frames and having a first surface (for example, the front surface 122f in FIG. 5) facing the stator 11 and a second surface (for example, the back surface 122r in FIG. 5). A linear motor 10 has a movable element 12 that moves relative to the stator 11, and an elastic motor that is attached to a shaft and is in contracted contact with one of the frames and an arm (bearing 22) of the stator 11. A body 20 is provided.

There are two shafts 21 and two elastic bodies 20 at positions parallel to the movable element 12 of the linear motor 10 and the propulsion direction (z-axis direction in the figure). The shaft 21 passes through the elastic body 20. Further, the shaft 21 slides in the moving direction of the movable element 12 via the stator 11 of the linear motor 10 and the bearing 22. In this embodiment, a sliding bearing whose metal surface is lubricated is used as the bearing 22.

The difference between the electromagnetic suspension 100C of the comparative example and the electromagnetic suspension 100 of the present invention is the center of vibration V ₀ shown by the broken line (the magnetic center of the mover is also the same in this figure) and the magnetic center of the stator shown by the dashed line. A ₀ is the point where they match. This positions the center of vibration (magnetic center of the mover) V ₀ and the magnetic center of the stator in order to increase the controllability and robustness of the linear motor 10 in the electromagnetic suspension 100C. .

However, as shown in FIG. 8, when the electromagnetic suspension 100C of the comparative example is used in an upright position in the direction of gravity, the movable member 12 is displaced in the direction of gravity from the set position due to the action of gravity. Furthermore, the gravitational energy of the vibration damping object Dt (see FIG. 9) is added, and the mover 12 is further displaced in the direction of gravity. In this case, the center of vibration V ₀ does not coincide with the magnetic center A ₀ of the stator indicated by the dashed line. In other words, the positioning of the stator 11 and movable element 12 that was adjusted to ensure controllability at the stage of the linear motor 10 becomes invalid.

As a measure to maintain the positioning of the stator 11 and mover 12 adjusted at the stage of the linear motor 10, for example, the electromagnetic suspension 100C of the comparative example shown in FIG. It is made larger in the z-axis direction than the magnet 124. This widens the controllable range even if the mover 12 shifts in the direction of gravity. Alternatively, this measure prevents the stroke from shifting in the direction of gravity. However, more magnets than necessary are used, resulting in a large and expensive motor.

As another countermeasure, a method may be considered in which a position sensor is placed on the movable element 12 for control, as disclosed in Patent Document 2, but the cost of the position sensor becomes a burden.

<Effects of the first embodiment>
As described above, according to the present embodiment, in the electromagnetic suspension 100 connected to the vibration damping object Dt, the electromagnetic suspension 100 is disposed in the vertical direction or inclined from the vertical direction, and the electromagnetic suspension 100 is arranged such that the stator 11 a linear motor 10 having at least two magnets 124 at positions facing the stator 11 and a movable element 12 that moves relative to the stator; an elastic body 20 that pushes the movable element 12 upward; If the center of vibration of the mover 12 is _V0 , then if the electromagnetic suspension 100 is not connected to the object Dt to be damped, _V0 will deviate from the center of the magnetic poles of the stator in the anti-gravity direction. It is located.

Therefore, in actual operation, the movable element 12 sinks due to the gravitational energy of the damping object Dt, and the positions of the movable element 11 and the stator 12 of the linear motor 10 are optimized. This makes it possible to provide a compact and low-cost electromagnetic suspension 100 without using redundant magnets or sensors.

<Modification of the first embodiment>
FIG. 15 is a diagram illustrating an excerpt of the cores 11a and 11b of the mover 12 and stator 11 in Modification 1 of the electromagnetic suspension 100 (see FIG. 1) according to the first embodiment. When the pitch of the magnet is MP, the control movable range (stroke length) of the movable element 12 is αMP (0<α≦2). Stroke length α=0 does not hold true as an electromagnetic suspension. Further, the position where the magnet 124a and the core 11a of the mover 12 oppose each other is the lower end, and the position where the magnet 124b and the core 11a face each other serves as the upper end, so the stroke length is αMP (α≦2). Note that FIG. 15 shows that the length of the movable element 12 in the direction of gravity is smaller than the stroke length.

In the comparative example, the magnets 124 (124a, 124b) are required to be long in the z-axis direction in order to face the core 11a even if the movable element 12 sinks due to the damping object Dt. In contrast, in Modification 1, the length of the movable element 12 in the gravity direction is smaller than the stroke length. That is, in the present modification example 1, since the magnet 124 can be reduced in the z-axis direction, the mover 12 can be made smaller, and can be made smaller than the stroke length αMP. Therefore, cost reduction is also possible.

FIG. 16 is a diagram showing an excerpt of the cores 11a and 11b of the mover 12 and stator 11 in the second modification of the electromagnetic suspension 100 (see FIG. 1) according to the first embodiment. When the pitch of the magnet is MP, the movable range (stroke length) of the movable element 12 is αMP (0<α≦2). The magnet 124b of the mover 12 is located above the stroke length αMP. Although this position is the upper end of the electromagnetic suspension, by connecting the vibration damping object Dt (see Fig. 9) above, the mover 12 sinks, so even if the positioning reference position is set at the upper end, the vertical amplitude can be secured. In other words, it is possible to downsize the electromagnetic suspension 100 without reducing the stroke length.

In the second modification, when the electromagnetic suspension 100 is not connected to the vibration damping object Dt, the lower end of the magnet of the mover 12 that is disposed at the lowest side in the direction of gravity is the lower end of the stroke length. It is characterized by being located above the

FIG. 17 is a perspective view showing an excerpt of the frame 122 and magnet 124 of the mover in the third modification of the electromagnetic suspension 100 (see FIG. 1) according to the first embodiment. In Modification 3, the magnets 124a and 124b of the mover 12 have different sizes. That is, the vibration center V ₀ of the movable element 12 (the magnetic center of the movable element) is different from the geometric center of the movable element 12 . For example, when the electromagnetic suspension 100 is used as a vibration damping device for a washing machine W (see FIG. 10) and the gravitational energy of the vibration damping object Dt changes between the washing process and the dehydration process, the magnet size may be different, for example 124a 124b can dampen vibrations during a heavy washing process that contains water, and 124b can dampen vibrations during a dehydration process. Furthermore, since excessive magnets are not required, it is possible to reduce the size and cost.

FIG. 18 is a perspective view showing an excerpt of the frame 122 and magnet 124 of the mover in Modification 4 of the electromagnetic suspension 100 according to the first embodiment. In modification 4, the types of magnets 124a and 124b of the mover 12 are different. That is, the vibration center V ₀ of the movable element 12 (the magnetic center of the movable element) is different from the geometric center of the movable element 12 . For example, if the electromagnetic suspension 100 is used as a vibration damping device for a washing machine W (see FIG. 10) and the gravitational energy of the vibration damping object Dt changes between the washing process and the dehydration process, different types of magnets may be used, for example. 124a can dampen vibrations during a heavy washing process that contains water, and 124b can dampen vibrations during a dehydration process. Furthermore, since excessive magnets are not required, it is possible to reduce the size and cost.

For example, the magnet 124a may be a neodymium sintered magnet with a high residual magnetic flux density, and the magnet 124b may be a low-cost ferrite magnet. Alternatively, a high-grade version (high residual magnetic flux density material) of neodymium sintered magnets may be applied to 124a, and an inexpensive version (low residual magnetic flux density material) may be applied to 124b.

[Second embodiment]
<Configuration of second embodiment>
FIG. 9 is a perspective view of an electromagnetic suspension 100B according to the second embodiment. In the following description, parts corresponding to those in the first embodiment described above may be denoted by the same reference numerals, and the description thereof may be omitted.

The electromagnetic suspension 100 includes the linear motor 10 according to the first embodiment and an elastic body 20. One end of the movable element 12 or one end of the stator 11 of the linear motor 10 is coupled to the vibration damping object Dt. In the figure, one end of the movable element 12 is coupled to an object to be damped. The connection to the vibration damping object Dt is not limited to the vertical direction, and may be connected at an angle θ (hereinafter referred to as attachment angle) with the vertical direction. On the other hand, it is preferable that the mounting angle θ is such that the movement of the movable element 12 is not parallel to the horizontal direction. This is to effectively utilize the gravitational energy of the vibration damping object Dt for damping the electromagnetic suspension 100.

Here, the vibration damping object Dt is an object whose vibration is to be suppressed by the electromagnetic suspension 100, and in the illustrated example, the vibration damping object Dt is an outer tub 37 of a washing machine W (see FIG. 10). be. The other end is connected to the base 31 of the washing machine W. Naturally, the electromagnetic suspension 100 may be placed upside down, and one end of the stator 11 may be coupled to the outer tank 37 (see FIG. 10), and one end of the mover may be coupled to the base 31.

Therefore, when the outer tub 37 of the washing machine vibrates in the z-axis direction, the movable element 12 reciprocates along the z-axis direction, and the relative positional relationship between the movable element 12 and the stator 11 changes.

Further, in this embodiment, a metal coiled spring is used as the elastic body 20. Here, the elastic body 20 provides elastic force to the movable element 12 and is located between the bearing 22 and the frame 23. As shown in FIG. 9, the shaft 21 also passes through the elastic body 20.

<Effects of the second embodiment>
As described above, the electromagnetic suspension 100 of the present embodiment includes the linear motor 10 according to the first embodiment and the elastic body 20 that biases the stator 11 or the movable element 12 in the moving direction (z-axis direction). . In particular, the elastic body 20 includes a metal coiled spring. As a result, the outer tub 37 of the washing machine and one end of the movable element 12 of the linear motor 10 or one end of the stator 11 are coupled to the vibration damping object Dt, so that the elastic body 20 sinks. Therefore, the positional relationship between the stator 11 and the movable element 12 changes in the direction of gravity.

[Third embodiment]
<Configuration of third embodiment>
(overall structure)
FIG. 10 is a perspective view of a washing machine W according to a third embodiment. The washing machine W shown in FIG. 10 is a drum-type washing machine, and also has a function of drying clothes. The washing machine W includes a base 31, a housing 32, a door 33, an operation/display panel 34, an outer tub 37, a pair of electromagnetic suspensions 100L and 100R, and a drain hose H. Here, the electromagnetic suspensions 100L and 100R are each configured similarly to the electromagnetic suspension 100 in the second embodiment. When viewed from the front (y-axis direction) of the washing machine, the electromagnetic suspensions 100L and 100R are joined to the outer tub 37 in a substantially "V" shape. In other words, a plurality of electromagnetic suspensions may be installed at an angle of θ so that the outer tank 37 is stabilized.

The housing 32 includes left and right side plates 32a, a front cover 32b, a back cover 32c (see FIG. 11), and a top cover 32d. The base 31 supports the housing 32. A circular slot h1 (see FIG. 11) for loading and unloading clothes is formed near the center of the front cover 32b. The door 33 is an openable/closeable lid provided on the input port h1.

FIG. 11 is a longitudinal sectional view of a washing machine W according to the third embodiment. The washing machine W includes a washing tub 35, a lifter 36, a drive device 38, and a blower unit 39 in addition to the above-described configuration. The washing tub 35 stores clothes and has a cylindrical shape with a bottom. The washing tub 35 is contained in an outer tub 37 and is rotatably supported on the same axis as the outer tub 37. The peripheral wall and bottom wall of the washing tub 35 are provided with a large number of through holes (not shown) for water and ventilation. Further, the opening h2 of the washing tub 35 faces the door 33 in the closed state, together with the opening h3 of the outer tub 37.

In the example shown in FIG. 11, the central axis of rotation of the washing tub 35 is inclined so that the opening side is higher, but the present invention is not limited to this. That is, the central axis of rotation of the washing tub 35 may be horizontal or vertical. The lifter 36 lifts and drops the clothes during washing and drying, and is installed on the inner peripheral wall of the washing tub 35. The outer tank 37 is used to store washing water and has a cylindrical shape with a bottom. As shown in FIG. 11, the outer tub 37 contains the washing tub 35.

Further, as shown in FIG. 10, electromagnetic suspensions 100L and 100R are arranged on the left and right sides of the outer tank 37, but in FIG. 9, only the left electromagnetic suspension 100L is shown. Further, a drainage hole (not shown) is provided at the lowest part of the bottom wall of the outer tank 37, and a drainage hose H is connected to this drainage hole. Washing water is stored in the outer tank 37 when a drain valve (not shown) provided on the drain hose H is closed, and the washing water is discharged when the drain valve is opened. It looks like this.

The drive device 38 is a mechanism for rotating the washing tub 35, and is installed outside the bottom wall of the outer tub 37. The rotating shaft of the motor included in the drive device 38 passes through the bottom wall of the outer tub 37 and is connected to the bottom wall of the washing tub 35 . The air blowing unit 39 sends warm air into the washing tub 35 and is arranged above the washing tub 35. The blower unit 39 includes a heater and a fan. Air heated by the heater is then sent into the washing tub 35 by the fan. As a result, the water-containing clothes are gradually dried in the washing tub 35.

Here, the vibration of the outer tub 37, that is, the vibration of the washing machine W will be briefly explained. During washing, rinsing, and drying, the washing tub 35 is rotated at low speed by a drive device 38 shown in FIG. 11, and a tumbling operation in which clothes accumulated at the bottom of the washing tub 35 are lifted up and dropped by a lifter 36 is repeated. Further, during dehydration, the washing tub 35 rotates at high speed, and centrifugal dehydration is performed in which the centrifugal force of the rotation pushes out moisture from the clothes.

In addition, in conventional washing machines, during washing, rinsing, and drying, the amplitude of the vibration of the washing tub 35 often increases due to the reaction force of falling clothes. Further, in conventional washing machines, vibrations and noises were often generated in the washing machine W during dehydration due to uneven positions of clothes containing water. As described above, the way the washing machine W vibrates changes from moment to moment depending on various conditions such as washing, rinsing, drying, and dehydration, as well as the amount and position of clothes in the washing tub 35, the moisture content, and the like. The vibration is propagated to the outer tank 37.

In other words, the vibration damping objects Dt in this embodiment include not only the outer tub 37 coupled to the electromagnetic suspension 100, but also the washing tub 35 connected to the outer tub 37, the laundry contained in the washing tub 35, and the drive device 38. , water stored in the outer tank 37, etc. are targeted.

Gravitational energy is generated in each object in proportion to the mass of the washing tub 35, the mass of the laundry contained in the washing tub 35, the mass of the drive device 38, the mass of the outer tub, and the mass of water stored in the outer tub 37. Then, the movable element 12 of the electromagnetic suspension 100 is pushed down in the direction of gravity. A portion of this gravitational energy is used to make the magnet 124 smaller and lower in cost.

The object of the damping object Dt can be selected separately by the designer. Three representative examples are shown below.
<Example 1> When the objects Dt to be damped are the outer tub 37, the washing tub 35, and the drive device 38.
All of them are components of a washing machine, and their masses are known. Therefore, the amount of depression of the elastic body 20 can be derived. After that, design a margin for the amount of laundry and water that general users throw in.
<Example 2> When the objects Dt to be damped are the outer tub 37, the washing tub 35, the drive device 38, half of the maximum washing capacity (for example, 6 kg), and water corresponding to the amount of laundry.
Both masses are known, so the amount of sinking of the elastic body 20 can be derived. After that, design a margin for the amount of laundry and water when a general user loads 6 kg or more of laundry.
<Example 3> When the vibration damping objects Dt are the outer tub 37, the washing tub 35, the drive device 38, the maximum washing capacity (for example, 12 kg), and water corresponding to the amount of laundry.
Both masses are known, so the amount of sinking of the elastic body 20 can be derived. The next step is to design margins in case of an abnormality.

Here, the gravitational energy of the vibration damping object Dt will be roughly estimated. According to the product catalog (Hitachi Global Life Solutions Co., Ltd.'s Washing Machine and Clothes Dryer General Catalog 2019-Summer), the mass of a drum washing machine with a maximum washing capacity of 12 kg is 82 kg. Roughly speaking, the mass of mechanical parts such as the outer tub 37, the washing tub 35, and the drive device 38 is about 70 kg. Also, assuming that about 40 L of water is poured into 12 kg of laundry, the maximum change in weight of the contents of the outer tub 37 is 52 kg (80% of the mechanical parts), and the total mass is 122 kg, and the gravitational energy is 1 .2kN. In this embodiment, any one or more of the washing tub 35 connected to the outer tub 37, the drive device 38, clothing, and the weight of water stored in the outer tub 37 may be selected as the vibration damping object Dt. Regardless of which option is selected, gravitational energy can be calculated or actually measured as described above. Based on this value, the amount of change in the movable element 12 can be designed by changing the characteristics of the elastic body 20. In particular, when the elastic body 20 is a spring, the spring constant may be determined.

Here, the difference between the electromagnetic suspension for home appliances of the present invention and the electromagnetic suspension for industrial applications such as automobiles and railways will be explained. First, customer requirements are different. The customers of home appliances are general consumers, and their primary requirements are for ``cheapness (low cost)'' and ``products that make life comfortable, convenient, and enriching.'' On the other hand, the customers of industrial electromagnetic suspension systems are companies and business operators, and their first requirement is "high reliability and safety."

Next, the vibration generation mechanism is significantly different. The washing machine is fixed at a fixed location in the room, such as near the bathroom. Further, as mentioned above, the vibration of the washing machine is caused by the uneven position of the clothes. Generally, the amount of rotational unbalance is calculated as the product of the distance from the rotation center axis of the occurrence position and the unbalance weight. In other words, when the inner diameter of the washing tub 35 is designed (once the capacity of the washing machine is determined), the rotational unbalance amount is proportional to the unbalanced weight. In other words, if we provide an electromagnetic suspension that isolates/isolates vibrations according to unbalanced weight at a low cost, customer satisfaction will improve (we can expect an increase in sales).

In contrast, vibrations from electromagnetic suspensions in automobiles, trains, etc. support moving bodies outdoors. Furthermore, vibrations are not controlled solely by the amount of unbalance, but vary greatly depending on, for example, the shape of the road surface, steering operation, and weather, and each factor is intricately intertwined. Therefore, controlling only the mass (gravitational energy) of the object to be damped does not necessarily improve damping performance. In other words, even if the structure of the electromagnetic suspension is simplified by using the gravitational energy of the object to be damped, this is not applicable because it violates "high reliability and safety."

(Configuration of vibration damping device 200)
FIG. 12 is a configuration diagram of a vibration damping device 200 applied to the third embodiment. In FIG. 12, the vibration damping device 200 includes an inverter 40, a current detector 50, a thrust adjustment section 60, a rectifier circuit 70, and left and right electromagnetic suspensions 100L and 100R. The vibration damping device 200 suppresses the vibration of the vibration damping object G. In this embodiment, the vibration damping object G is the outer tub 37 of the washing machine W (see FIG. 10).

In FIG. 12, the left and right electromagnetic suspensions 100L and 100R are represented by one frame. Furthermore, the linear motors 10 included in the electromagnetic suspensions 100L and 100R are referred to as linear motors 10L and 10R, respectively. Similarly, the elastic bodies 20 included in the electromagnetic suspensions 100L and 100R are referred to as elastic bodies 20L and 20R.

The rectifier circuit 70 rectifies the AC voltage applied by the AC power source E and applies a DC voltage to the inverter 40. Note that the AC power source E and the rectifier circuit 70 may be considered to be a DC power source together. The inverter 40 converts the DC voltage applied from the rectifier circuit 70 into a single-phase AC voltage based on the voltage command V ^* from the thrust adjustment unit 60, and applies this single-phase AC voltage to the windings of the linear motors 10L and 10R. 11b (see FIG. 2). In other words, the inverter 40 has a function of driving the linear motors 10L and 10R based on the voltage command V ^* .

FIG. 13 is a configuration diagram of main parts of a vibration damping device 200 applied to the third embodiment. The rectifier circuit 70 is a well-known voltage doubler rectifier circuit that converts an AC voltage applied from an AC power source E into a DC voltage. As shown in FIG. 13, the rectifier circuit 70 includes a diode bridge circuit 72 formed by bridge-connecting diodes D1 to D4, and two smoothing capacitors 74 and 76 connected in series. Further, the drive device 38 shown in FIG. 13 includes an inverter 38a and a motor 38b, as shown in FIG.

Then, the voltage (DC voltage including pulsating current) generated by the diode bridge circuit 72 is smoothed by the smoothing capacitors 74 and 76, and a DC voltage equivalent to approximately twice the voltage of the AC power supply E is generated. The rectifier circuit 70 is connected to the inverter 40 via the positive side wiring k1 and the negative side wiring k2, and is also connected to the inverter 38a of the drive device 38 that rotates the washing tub 35 (see FIG. 11). There is.

The inverter 40 converts the DC voltage applied from the rectifier circuit 70 into two systems of single-phase AC voltage, and applies these two systems of single-phase AC voltage to the windings 11b (see FIG. 4) of the linear motors 10L and 10R, respectively. This is an inverter that applies the voltage.

As shown in FIG. 13, the inverter 40 includes a first leg including switching elements SW1 and SW2, a second leg including switching elements SW3 and SW4, and a third leg including switching elements SW5 and SW6. are connected in parallel. For example, IGBTs (Insulated Gate Bipolar Transistors) can be used as these switching elements SW1 to SW6. A free wheel diode D is connected in antiparallel to each of the switching elements SW1 to SW6.

Further, the connection point between the switching elements SW1 and SW2 is connected to the winding 11b (see FIG. 4) of the linear motor 10L via a wiring k3. That is, a leg corresponding to one phase of the three-phase inverter 40 is connected to the left linear motor 10L. Moreover, the connection point of switching elements SW5 and SW6 is connected to the winding 11b (see FIG. 4) of the linear motor 10R via a wiring k5. That is, another leg corresponding to one phase of the three-phase inverter 40 is connected to the right linear motor 10L.

Further, the connection point of switching elements SW3 and SW4 is connected to the winding 11b of the linear motor 10L (see FIG. 4) via a wiring k4, and also to the winding 11b of the linear motor 10R via this wiring k4. It is connected. That is, the remaining legs of the three-phase inverter 40 are connected to the left and right linear motors 10L and 10R.

In this way, instead of separately providing inverters corresponding to the left and right linear motors 10L and 10R, the cost of the inverter 40 can be reduced by using a single inverter 40 for the left and right linear motors. Then, by controlling the on/off of switching elements SW1 to SW6 based on PWM (Pulse Width Modulation) control, a single-phase AC voltage is applied to the windings 11b (see FIG. 4) of the linear motors 10L and 10R. It has become so.

The current detector 50 detects the current flowing through the linear motors 10L and 10R, and is inserted into the wiring k4. That is, the current detector 50 detects the current flowing through the windings 11b (see FIG. 4) of the linear motors 10L and 10R.

(Thrust adjustment section 60)
The thrust adjustment unit 60 shown in FIG. 12 is configured to include electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces, although illustrations are omitted. . Then, the program stored in the ROM is read out and expanded to the RAM, and the CPU executes various processes.

In FIG. 12, the thrust adjustment unit 60 has a function of adjusting the thrust of the linear motors 10L and 10R by driving the inverter 40 based on the current i detected by the current detector 50. That is, the thrust adjustment unit 60 detects the polarity of the current i flowing through the current detector 50 during the dead time of the inverter 40. The polarity of the current i indicates the direction of movement of the linear motors 10L, 10R.

Therefore, the thrust adjustment unit 60 generates a voltage command V ^* in the direction of suppressing the movement of the linear motors 10L and 10R, and turns on and off the switching elements SW1 to SW6 based on this voltage command V ^* . As a result, when the relative position between the movable element 12 and the stator 11 changes due to the vibration of the outer tank 37 (see FIG. 11), the thrust force adjustment unit 60 adjusts the thrust of the linear motors 10L and 10R to cancel this change. It has the function to adjust.

<Effects of the third embodiment>
As described above, the washing machine W of the present embodiment includes the electromagnetic suspensions 100L and 100R according to the second embodiment, the inverter 40 that supplies alternating current to the armature winding (winding 11b), and the inverter 40 that supplies alternating current to the armature winding (winding 11b). The linear motor 10 further includes a current detector 50 that detects a flowing current, and a thrust adjustment section 60 that adjusts the thrust of the linear motor 10 by controlling the inverter 40 based on the current detected by the current detector 50.

Thereby, the current flowing through the armature winding can be detected by the current detector 50, and the thrust of the linear motor 10 can be adjusted so as to suppress the relative movement of the stator 11 and the movable element 12.

Furthermore, the washing machine W of the present embodiment includes a washing tub 35 for storing clothes, an outer tub 37 containing the washing tub 35 (see FIG. 11), and a drive device 38 for rotating the washing tub (see FIG. 11). , and the electromagnetic suspensions 100L and 100R suppress vibrations of the outer tank 37.

Thereby, according to this embodiment, vibration of the outer tank 37 can be suppressed with a relatively simple configuration. Further, according to the present embodiment, since there is no need to provide a position sensor for detecting the position of the movable element 12, the cost of the washing machine W can be reduced. Furthermore, the stator 11 and movable element 12, which are the constituent elements of the linear motors 10L and 10R, are hardly damaged or worn out, so the durability of the electromagnetic suspensions 100L and 100R can be increased.

Moreover, according to this embodiment, the single-phase AC voltage applied to the left and right linear motors 10L, 10R can be generated by one inverter 40 having six switching elements. If inverters were provided individually for the left and right linear motors 10L and 10R, eight switching elements would be required. Therefore, according to this embodiment, the cost of the washing machine W can be reduced compared to a configuration in which inverters are individually provided for the left and right linear motors 10L, 10R.

[Effects of other control examples in the third embodiment]
Next, another control example of the third embodiment will be described. The configuration and operation of the washing machine are similar to those of the third embodiment (see FIGS. 10 to 13). However, in this embodiment, the thrust adjustment section 60 (see FIG. 12) detects the vibration frequency of the left and right linear motors 10L, 10R based on the output signal of the current detector 50, and adjusts the vibration frequency of the inverter 40 according to the vibration frequency. The difference is that the output current is changed.

First, in the third embodiment described above, the output current of the inverter 40 is not changed based on the vibration frequencies of the linear motors 10L and 10R. That is, when considering the linear motors 10L and 10R as "dampers", in the third embodiment, the viscous damping coefficient C [Ns/m] of the dampers is constant regardless of the vibration frequency. On the other hand, in this embodiment, the viscous damping coefficient C [Ns/m] is changed according to the vibration frequency of the linear motors 10L, 10R. The details will be explained below.

The equation of motion of the electromagnetic suspension 100, which is an electromagnetic suspension, is expressed by equation (1). Note that F _D [N] shown in equation (1) is the force generated by the electromagnetic suspension 100 (that is, the thrust of the linear motor 10). Moreover, x[m] is the position of the movable element 12.

Further, the equation of motion of the thrust of the linear motor 10 is expressed by equation (2). Note that F _L [N] is the thrust of the linear motor 10, and K _e [N/A] is the motor constant of the linear motor 10. Further, I[A] is a current flowing through the winding 11b (see FIG. 4), and V[V] is a voltage applied to the winding 11b. Further, R[Ω] is the resistance of the winding 11b, and φ[T] is the magnetic flux generated in the winding 11b.

Here, since the force F _D in equation (1) and the thrust force F _L in equation (2) are equivalent, the following equation (3) is derived. Note that C [N·m/s] is the viscous damping coefficient of the linear motor 10.

FIG. 14A shows experimental results showing changes in the rotational speed of the washing tub 35 and the displacement (vibration) of the outer tub 37 in a comparative example using an oil damper (hydraulic damper) with a constant viscous damping coefficient C. On the x-axis, the range from zero rotation speed to the maximum rotation speed of the washing machine W is expressed as a percentage. The y-axis shows the displacement (vibration) of the outer tank 37 as a relative value when the rotation speed is zero. In the experiment shown in FIG. 14, the washing tub 35 was rotated while 1 kg of clothing was placed at a predetermined, biased position inside the washing tub 35.

As shown in FIG. 14A, as the rotational speed of the washing tub 35 increases, the amplitude of the outer tub 37 changes. Specifically, when the rotational speed of the washing tub 35 is increased from zero, the amplitude of the outer tub 37 decreases once at a rotational speed of about 5%, and the amplitude of the outer tub 37 decreases at a rotational speed of about 10%. The amplitude increases rapidly and reaches its maximum amplitude. In addition, the amplitude of the outer tub 37 increases at a rotation speed of 10 to 17 [%], and in the region of 20 [%] or more, as the rotation speed of the washing tub 35 increases, the amplitude of the outer tub 37 decreases. There is.

FIG. 14B is an experimental result showing changes in the rotational speed of the washing tub 35 and the displacement (vibration) of the outer tub 37 using the electromagnetic suspension of the comparative example shown in FIG. 8 in another control example of the third embodiment. . In the experiment shown in FIG. 14B, the duty ratio of the inverter 40 was adjusted so that the higher the rotational speed of the washing tub 35 (that is, the higher the vibration frequency f of the outer tub 37), the smaller the viscous damping coefficient C of the linear motor 10. controlled.

As shown in FIG. 14B, when the rotation speed of the washing tub 35 is about 10%, the maximum amplitude of the outer tub 37 is about 5[PU], and the maximum amplitude of the comparative example shown in FIG. PU]). Further, in a region where the rotational speed of the washing tub 35 is 50% or higher, the amplitude of the outer tub 37 is approximately 1 PU. In this manner, according to the third embodiment, by variably controlling the viscous damping coefficient C, vibrations of the outer tank 37 can be suppressed more effectively than when an oil damper is used.

FIG. 14C shows experimental results showing changes in the rotational speed of the washing tub 35 and the displacement (vibration) of the outer tub 37 using the electromagnetic suspension 100 of the present embodiment shown in FIG. 1 in another control example of the third embodiment. It is. In the experiment shown in FIG. 14C, it can be seen that the damping performance is dramatically improved compared to FIG. 14B. The value is ±2 [PU] or less regardless of the rotation speed.

From the above, when the electromagnetic suspension 100 is not connected to the vibration damping object Dt, the center of vibration V ₀ of the movable element 12 of the linear motor 10 that constitutes the electromagnetic suspension 100 is larger than the magnetic A ₀ of the stator. It was confirmed that it is effective to shift the arrangement in the anti-gravity direction.

[Modified example]
The present invention is not limited to the embodiments described above, and various modifications are possible. The embodiments described above are exemplified to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to delete a part of the configuration of each embodiment, or add or replace other configurations. Furthermore, the control lines and information lines shown in the figures are those considered necessary for explanation, and do not necessarily show all the control lines and information lines necessary on the product. In reality, almost all components may be considered to be interconnected. Possible modifications to the embodiment described above are, for example, as follows.

(1) In each of the above embodiments, as shown in FIG. 5, the mover 12 is configured by fitting two rectangular plate-shaped magnets 124a and 124b into one rectangular plate-shaped frame 122. did. However, one magnet may be attached to one frame 122. Further, a plurality of magnets may be attached to each of the plurality of frames. Further, the shapes of the frame 122 and the magnet 124 are not limited to rectangular plate shapes, and various shapes can be adopted.

(2) Furthermore, in FIG. 6A, the S and N poles of the magnets 124a and 124b and the magnetization directions of the magnetic teeth 151 and 152 may be reversed.

(3) Furthermore, in the second and third embodiments, an example was explained in which the electromagnetic suspension 100 was applied to vibration damping of a washing machine W, but the electromagnetic suspension 100 is applied to home appliances such as an air conditioner and a refrigerator. can also be applied.

(4) Furthermore, in each of the embodiments described above, a configuration has been described in which the linear motor 10 is driven by a single-phase alternating current, but for example, the linear motor 10 may be driven by a three-phase alternating current.

(5) In each embodiment, an example is shown in which an even number of shafts 21 and an even number of elastic bodies 20 are used, but the invention is not limited to an even number. As long as a large surface structure can be constructed and mechanical strength can be ensured so that stress in directions other than the propulsion direction caused by vibrations does not concentrate on the movable element 12, the number and number of movable elements are not limited.

As described above, according to the present embodiment, in the electromagnetic suspension connected to the vibration damping object Dt, the electromagnetic suspension 100 is arranged in the vertical direction or inclined from the vertical direction, and the electromagnetic suspension 100 is connected to the stator 11. , a linear motor 10 having at least two magnets 124 at positions facing the stator 11 and a movable element 12 that moves relative to the stator, and an elastic body 20 that pushes the movable element 12 upward. Assuming that the center of vibration of the mover 12 is _V0 , when the electromagnetic suspension 100 is not connected to the vibration damping object Dt, _V0 is disposed offset from the center of the magnetic pole of the stator in the anti-gravity direction. has been done. Therefore, in actual operation, the movable element 12 sinks due to the gravitational energy of the damping object Dt, and the positions of the movable element 11 and the stator 12 of the linear motor 10 are optimized. This makes it possible to provide a compact and low-cost electromagnetic suspension 100 without using redundant magnets or sensors.

Further, in the electromagnetic suspension of the present embodiment, in the electromagnetic suspension connected to the vibration damping object Dt, the electromagnetic suspension 100 is arranged in a vertical direction or inclined from the vertical direction, and the electromagnetic suspension 100 connects the frames 23. A magnet fixed between a pair of opposing shafts 21, a stator 11 having an armature core and an armature winding, and a frame 23, and having a first surface and a second surface facing the stator 11. Alternatively, the linear motor 10 includes a movable element 12 that is made of a magnetic material and moves relative to the stator 11; ), and if the center of vibration of the mover 12 is V ₀ , then when the electromagnetic suspension 100 is not connected to the vibration damping object Dt, V ₀ is the stator It is arranged offset from the center of the magnetic pole No. 11 in the anti-gravity direction. Therefore, in actual operation, the movable element 12 sinks due to the gravitational energy of the damping object Dt, and the positions of the movable element 11 and the stator 12 of the linear motor 10 are optimized. This makes it possible to provide a compact and low-cost electromagnetic suspension 100 without using redundant magnets or sensors.

10, 10L, 10R Linear motor 11 Stator 11a Core (armature core)
11b Winding (armature winding)
11a1 Core back part (armature core)
11a2 Teeth part (armature core)
11a3 Tee stop part (armature core)
12 Mover 20, 20L, 20R Elastic body 21 Shaft 22 Bearing (arm)
23 Frame 25 Rotation bearing 35 Washing tub 37 Outer tub 38 Drive device 40 Inverter 50 Current detector 60 Thrust adjustment section 100, 100L, 100R Electromagnetic suspension 100C Electromagnetic suspension of comparative example 122 Frame 122f Surface (first surface)
122h Through hole 122r Back surface (second surface)
124, 124a, 124b Magnet 124N N-pole surface 124S S-pole surface 151 Magnetic tooth (first magnetic tooth)
152 Magnetic tooth (second magnetic tooth)
A ₀ Magnetic center of stator Dt Vibration damping object TL Magnetic tooth width (width)
TP Magnetic tooth pitch UL Common use range length (range length)
V ₀ Center of vibration W Washing machine z Z-axis direction (movement direction)

Claims (11)

In the electromagnetic suspension connected to the object to be damped,
The electromagnetic suspension is arranged in a vertical direction or inclined from the vertical direction,
The electromagnetic suspension includes a stator, at least two magnets located opposite the stator, and a movable element that moves relative to the stator;
an elastic body that pushes the mover upward;
If the center of vibration of the movable element is V ₀ ,
When the electromagnetic suspension is not connected to the vibration damping object,
An electromagnetic suspension characterized in that the V ₀ is disposed offset from the center of the magnetic pole of the stator in an anti-gravity direction. In the electromagnetic suspension connected to the object to be damped,
The electromagnetic suspension is arranged in a vertical direction or inclined from the vertical direction,
The electromagnetic suspension includes a stator, at least two magnets located opposite the stator, and a movable element that moves relative to the stator;
an elastic body that pushes the mover upward;
If the magnetic center of the movable element is M _C ,
When the electromagnetic suspension is not connected to the vibration damping object,
An electromagnetic suspension characterized in that the _MC is disposed offset from the center of the magnetic pole of the stator in an anti-gravity direction. The electromagnetic suspension according to claim 1 or 2,
An electromagnetic suspension characterized in that the length of the mover in the direction of gravity is smaller than the stroke length. The electromagnetic suspension according to claim 1 or 2,
When the electromagnetic suspension is not connected to the vibration damping object,
An electromagnetic suspension characterized in that, among the magnets of the movable element, the lower end of the lowermost magnet in the direction of gravity is located above the lower end of the stroke length. The electromagnetic suspension according to claim 1 or 2,
The movable element includes at least two magnets located opposite the stator,
An electromagnetic suspension characterized in that the size of at least one of the magnets is different. The electromagnetic suspension according to claim 1 or 2,
The movable element includes at least two magnets located opposite the stator,
An electromagnetic suspension characterized in that at least one type of the magnet is different. The electromagnetic suspension according to claim 1 or 2,
An electromagnetic suspension characterized in that the elastic body is a metal coiled spring. The electromagnetic suspension according to claim 1 or 2,
an inverter that supplies alternating current to the linear motor;
a current detector that detects the current flowing through the linear motor;
An electromagnetic suspension comprising: a thrust adjustment section that adjusts the thrust of the linear motor by controlling the inverter based on the current detected by the current detector. The electromagnetic suspension according to claim 1 or 2,
The gravitational energy applied to the vibration damping object is
The mass of the washing tub that houses the clothes, the mass of the outer tub containing the washing tub, the mass of the drive device that rotates the washing tub, the mass added to the clothes, and the mass of water poured into the outer tub. An electromagnetic suspension characterized by being generated by one or more masses. In the electromagnetic suspension connected to the object to be damped,
The electromagnetic suspension is arranged in a vertical direction or inclined from the vertical direction,
The electromagnetic suspension includes a pair of opposing shafts connecting frames;
a stator having an armature core and an armature winding; a magnet or a magnetic body fixed between the frames and having a first surface and a second surface facing the stator; a linear motor having a movable element that moves relative to the child;
an elastic body attached to the shaft and contracted between one of the frames and an arm of the stator;
If the center of vibration of the movable element is V ₀ ,
When the electromagnetic suspension is not connected to the vibration damping object,
An electromagnetic suspension characterized in that the V ₀ is disposed offset from the center of the magnetic pole of the stator in an anti-gravity direction. The electromagnetic suspension according to any one of claims 1 to 10,
A washing tub for storing clothes;
an outer tank containing the washing tub;
A drive device that rotates the washing tub,
The washing machine, wherein the electromagnetic suspension suppresses vibrations of the outer tub.

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