TWI665850B - Linear actuator, vibration damping device and washing machine - Google Patents

Abstract

The object of the present invention is to provide a small-sized, low-cost brake, and low-torque linear actuator.

The solution of the present invention is a linear actuator including a stator and a mover that moves opposite to the stator, and is characterized in that the stator has a field coil, the mover has a permanent magnet, and the magnetism wound around the field coil is magnetic. Complementary poles are provided between the teeth. In the moving range of the movable element, the magnetic pole of the permanent magnet facing the complementary pole is fixed.

Description

Linear actuator, vibration damping device and washing machine

The present invention relates to a linear actuator for suppressing vibrations generated by a vibration damping object, and a vibration damping device for a washing machine provided with the linear actuator.

Review linear motors or linear actuators as linear motion motors. Compared with a geometrically symmetrical, circular motor, a linear motor with a straight end and a linear motor has more parts and more complicated assembly. Patent Document 1 describes a method for improving the productivity of a linear motor by linearly connecting constituent parts (first magnetic teeth) of an armature that has been previously formed into the same shape. In addition, there is also described an example in which the first magnetic teeth are assembled without winding a coil, and the magnetic teeth (second magnetic pole teeth) are made and used as complementary poles.

In addition, Patent Document 2 describes a linear motor that can be divided up and down with a movable element as the center, and has a structure of a complementary pole.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2007-185033

[Patent Document 2] Japanese Patent Laid-Open No. 2016-101019

The problems of linear motors can be exemplified. Compared with rotary motors, their size is larger and the cost is higher. Therefore, there are linear and linear actuators for small and low cost rotary motor combination gears on the market. In other words, in the case where inexpensive rotary motors are provided with parts such as gears, they are relatively inexpensive and small.

However, the technology described in Patent Document 1 is directed to a three-phase motor, and the magnetic teeth need to be arranged in multiples of three (FIG. 9), and the size is further increased and the cost is higher. Furthermore, in the case where magnetic teeth are used as a complementary pole, the magnetic teeth are directly used as a complementary pole without winding a coil, and cogging or torque ripple reduction effects are also limited. Furthermore, since it is not easy to obtain magnetic balance in a three-phase motor, it is shown that the third magnetic teeth are arranged on both sides of the connecting part of the first magnetic tooth and the second magnetic tooth. Figure 11).

In addition, even if the complementary poles (the first auxiliary magnetic poles in FIG. 3) are arranged up and down (see FIG. 1) described in Patent Document 2, the magnetic flux vector will collide with each other within the complementary member, which will not help. Due to the torque characteristics of linear motors. That is caused by complementation. Moreover, the review of the relationship between the brake source, that is, the position of the magnet and the position of the mover, is not sufficient. The positive and negative pulsations of the brake across 0 have limited reduction effects (Figure 7).

Furthermore, linear motors and linears are used for vibration damping devices. The actuator does not want to make the motor a source of vibration, and requires extremely low cogging torque and low torque ripple in the movable range. However, there is no use description in Patent Document 1, and the general theory of reducing cogging torque by using a complementary pole is listed only in vague terms. Patent Document 2 describes a use for an air compressor, but is different from a vibration suppression application. Therefore, the allowable amount of brake and torque ripple is not the same.

Therefore, the present invention provides a linear actuator that does not increase the size of the linear actuator, and ensures excellent characteristics and economy. Furthermore, a damper or vibration damping indicating mechanism using the linear actuator is provided to a home appliance such as a washing machine, so that vibration damping performance can be improved.

In order to solve the above-mentioned problem, the present invention is, as an example, a linear actuator including a stator and a mover that moves opposite to the stator, and is characterized in that the stator has a field coil and the mover has a permanent magnet. A complementary pole is provided between the magnetic teeth wound by the field coil, and a magnetic pole of the permanent magnet facing the complementary pole is fixed in a moving range of the movable element.

According to the present invention, a small-sized, low-cost brake, and low-torque linear actuator can be provided. Furthermore, the vibration damping device to which the linear actuator is applied can appropriately control the vibration of the vibration damping object with relatively easy control and low cost. In addition, by applying the vibration damping device to a vibration-proof support mechanism for white goods such as washing machines, it is possible to improve Provides low-cost home appliances with excellent vibration damping properties.

100‧‧‧ Vibration suppression device

10‧‧‧ Linear actuator

10L‧‧‧ linear actuator (one linear actuator)

10R‧‧‧ linear actuator (the other linear actuator)

11‧‧‧ stator

12‧‧‧ mover

121b, 122b, 123b‧‧‧ Permanent magnet

20‧‧‧Spring

35‧‧‧Laundry trough

37‧‧‧Outer groove (vibration object)

38‧‧‧Drive mechanism

40‧‧‧ Inverter

50‧‧‧Current Detector

60‧‧‧Thrust adjusting section

G‧‧‧ Vibration target

W‧‧‧Washing machine

CP‧‧‧ Complement

FIG. 1 is a longitudinal sectional perspective view of a linear actuator provided in a vibration damping device according to a first embodiment of the present invention.

FIG. 2 is an end view in the direction of arrows II-II in FIG. 1.

3 is an end view in the direction of arrows III-III in FIG. 1.

Fig. 4-1 is a longitudinal sectional front view of a linear actuator provided in a vibration damping device according to a first embodiment of the present invention.

Fig. 4-2 is a longitudinal sectional front view of a linear actuator provided in a vibration damping device according to a first embodiment of the present invention.

FIG. 5 shows experimental results regarding the thrust characteristics of a linear actuator according to an embodiment of the present invention.

FIG. 6 is a graph showing the relationship between the width of the compensation CP of a linear actuator according to an embodiment of the present invention and the torque ripple.

FIG. 7 is a contour map showing the magnetic flux density inside the linear actuator according to the embodiment of the present invention.

FIG. 8 is an experimental result of a coil flux of a linear actuator according to an embodiment of the present invention.

Fig. 9 is a perspective view of a vibration damping device according to a first embodiment of the present invention.

10 is a perspective view of a washing machine provided with a vibration damping device according to a first embodiment of the present invention.

Fig. 11 shows a washing machine equipped with a vibration damping device according to a first embodiment of the present invention. Vertical section view of a clothes machine.

Fig. 12 is a configuration diagram of a vibration damping device according to a first embodiment of the present invention.

FIG. 13 is a configuration diagram including an inverter included in the vibration damping device according to the first embodiment of the present invention.

FIG. 14A is a comparative example in which an oil damper with a fixed viscosity coefficient is used, and shows the experimental results of changes in the rotation speed of the washing machine and the displacement of the outer tank.

FIG. 14B is an experimental result showing changes in the rotation speed of the washing tub and the displacement of the outer tub in the embodiment of the present invention.

In each of the following embodiments, as an example, a configuration in which the vibration of the washing machine W (see FIG. 10) is suppressed by the linear actuator 10 (see FIG. 1) will be described.

≪First implementation type≫

FIG. 1 is a longitudinal sectional view of a linear actuator 10 included in the vibration damping device.

The xyz axis is determined as shown in FIG. 1. In addition, in FIG. 1, a half of the linear actuator 10 is shown in the x direction, but the configuration of the linear actuator 10 is symmetrical with reference to the yz plane.

The linear actuator 10 uses the magnetic attraction / repulsion (ie, thrust) between the stator 11 of the armature and the plate-like movable element 12 extending in the z direction, so that the relative position of the stator 11 and the movable element 12 is in the z direction. Actuator on a linear change. As shown in FIG. 1, a linear actuator 10 is connected to a washing machine W (see FIG. 11). Outer groove 37 (object to be damped). Specifically, the movable element 12 of the linear actuator 10 is connected to the outer groove 37.

As shown in FIG. 1, the linear actuator 10 includes a stator 11 and a mover 12. The stator 11 includes a core 11a in which an electromagnetic steel sheet is laminated in the z direction, a winding wire 11b wound around the magnetic pole teeth T of the core 11a, and a complementary CP in which the winding wire 11b is not wound around the convex portion of the core 11a. .

FIG. 2 is an end view in the direction of arrows II-II in FIG. 1. In addition, in FIG. 2, not the half of the linear actuator 10 in the x direction (see FIG. 1), but the entire linear actuator 10 is shown.

As shown in FIG. 2, the core 11 a of the stator 11 includes an annular portion S1 and magnetic pole teeth T, T.

The ring-shaped portion S1 has a ring shape (rectangular frame shape) in a longitudinal cross-section, and a magnetic circuit is constituted by the ring-shaped portion S1. A pair of magnetic pole teeth T, T extend from the ring-shaped portion S1 to the inner side in the y direction and face each other. The distance between the magnetic pole teeth T and T is slightly longer than the thickness of the plate-shaped movable element 12. Winding wires 11b are wound around the magnetic pole teeth T and T, respectively. When the winding wire 11b is energized, the stator 11 functions as an electromagnet.

The magnetic flux flow generated by the electromagnet in the annular portion S1 and the permanent magnet (see FIG. 1) of the movable element 12 is annular as shown by arrows in the figure.

FIG. 3 is an end view in the direction of arrows III-III in FIG. 1. In addition, in FIG. 3, not the half of the linear actuator 10 in the x direction (see FIG. 1), but the entire linear actuator 10 is shown.

As shown in FIG. 3, the core 11a of the stator 11 includes an annular portion S2, Polar tooth TCP, TCP.

The ring-shaped portion S2 has a ring shape (rectangular frame shape) in a longitudinal section, and a magnetic circuit is configured by the ring-shaped portion S2. A pair of complementary teeth TCP and TCP extend from the ring-shaped portion S2 to the inner side in the y direction and face each other. The distance between the complement teeth TCP and TCP is slightly longer than the thickness of the plate-shaped movable element 12. The coils 11b are not wound around the complement teeth TCP and TCP.

The magnetic flux flow generated by the movable element 12 (not shown) in the annular portion S2 is annular as shown by a dotted arrow in the figure.

In short, the characteristics of the linear actuator 10 are determined by the sum of the magnetic flux vectors in the annular portion S1 in FIG. 2 and in the annular portion S2 in FIG. 3. In short, if the brake and torque ripple can be reduced, and the sum of the magnetic flux vectors can be optimized to meet the specifications for the purpose.

In the example shown in FIG. 1, two pairs of magnetic pole teeth T are provided in the z direction (moving direction of the movable element 12), and one pair of complementary poles CP is provided between the magnetic pole teeth T. In order to reduce the size of the linear actuator 10, the z-direction length of the complementary pole CP is preferably shorter than the length of the magnetic pole teeth T. In addition, each of the winding wires 11b wound around two pairs of magnetic pole teeth T is made into one winding wire, and both ends thereof are connected to the output side of an inverter 40 (see FIG. 12) described later.

The movable element 12 shown in FIG. 1 extends through the core 11 a having a ring shape and extends in the z direction. In addition, as shown in FIG. 1, the mover 12 includes a plurality of metal plates 12 a extending in the z direction, and permanent magnets 121 b, 122 b, and 123 b provided at a predetermined interval in the z direction and provided on the metal plate 12 a. In addition, a plurality of permanent magnets may be attached to one metal plate, and a plurality of permanent magnets may be buried in one metal plate.

The permanent magnets 121b, 122b, and 123b shown in FIG. 1 are magnetized in the y direction. To explain in more detail, a permanent magnet (for example, permanent magnets 121b, 123b) magnetized in the positive direction of the y direction and a permanent magnet (for example, permanent magnet 122b) magnetized in the negative direction of the y direction, Interactive configuration in the z direction. Next, by using the gravitational force and repulsive force of the movable element 12 and the stator 11 serving as an electromagnet, a thrust in the z direction is applied to the movable element 12. The “thrust” is a force that changes the relative position of the movable element 12 and the stator 11.

In addition, as the permanent magnets 121b, 122b, and 123b, it is preferable to use a rhenium (Sm) -iron-nitrogen-based permanent magnet. The specific ratio (weight%) of the raw materials of the permanent magnets 121b, 122b, and 123b, for example, about 73% iron, about 24% hafnium, and about 3% nitrogen. Among the aforementioned raw materials, the rare earth element is europium.

For this reason, in the past neodymium (Nd) magnets, about 65% of iron, about 28% of neodymium, about 5% of dysprosium (Dy), and about 2% of boron were used. Among the aforementioned raw materials, the rare earth elements are neodymium and praseodymium. Therefore, the ratio of rare-earth elements of the gadolinium-iron-nitrogen-based permanent magnets 121b, 122b, and 123b is smaller than that of the previous neodymium magnets, so it is not easily affected by market trends and has the advantage of improving productivity.

Furthermore, unlike the conventional neodymium magnets or ferrite magnets, the praseodymium-iron-nitrogen-based permanent magnets 121b, 122b, and 123b can be kneaded in resin to form a mold. Therefore, compared with the previous magnets, the processing accuracy of the permanent magnets 121b, 122b, and 123b can be improved, and the size dispersion can be reduced. In addition, even the scraps of the raw materials can be reused during the molding of the mold. There is no loss of raw materials, and the manufacturing cost can be reduced.

The length in the z direction of the permanent magnet 122b shown in FIG. 1 is set to be longer than the sum of the length of the movable range X of the mover 12 and the length in the z direction of the complement CP. Thereby, the polarity of the permanent magnet 122b facing the complementary pole CP is fixed. In short, the polar N pole, S pole, ... N pole of the permanent magnets facing the complementary pole CP do not change like ordinary linear actuators.

FIGS. 4-1 and 4-2 are vertical sectional front views of the linear actuator 10 provided in the vibration damping device.

Details are described with reference to FIGS. 4-1 and 4-2. In the linear actuator 10 shown in FIG. 4-1 (a), it is preferable that the z-direction length of the magnetic pole tooth T length TL is longer than the movable range X of the movable element 12, and the length ML of the permanent magnet 122b is longer than The pitch TP of the magnetic teeth is also large. Fig. 4-1 (b) shows an example of the magnetic flux direction when the coil is energized (the movable element 12 is not shown for illustration). The arrangement of the magnetic poles when the core 11a is to be a magnetic pole and current is applied to the winding wire 11b is shown. Although the magnetic pole teeth T are respectively N-pole and S-pole, the complementary pole CP is de-energized so as to have the same current direction as the adjacent coil. In addition, in FIG. 4-1 (c), when the winding 11b is energized in a direction opposite to that of FIG. 4-1 (b), each magnetic pole tooth T can be reversed into an S pole and an N pole. Fig. 4-2 (d) is an example of the direction of the permanent magnet magnetic flux. The linear actuator 10 of this embodiment uses the switching of the current direction of the winding wire 11b to control the magnetic attraction and generate thrust. FIG. 4-2 (e) shows the left end of the movable range of the linear actuator 10, and FIG. 4-2 (f) shows the right end. In this embodiment, regardless of the left and right ends of the moving range of the movable element 12, the two pairs of magnetic pole teeth T and the complementary pole CP are opposed to the permanent magnet 122b. With this, even if the coil is not energized (Fig. 4-2 (d)), or the mover is at the left end, the magnetic flux of the permanent magnet is the same vector as that of the electromagnet (Fig. 4-2 (e)), or the mover is at the right end ,permanent The magnetic flux of a magnet is opposite to the magnetic flux of an electromagnet (Figure 4-2 (f)). In either case, the magnetic path of the magnetic flux in the same direction (the solid line is the downward arrow) in the complementary CP.

FIG. 5 shows the experimental results on the thrust of the linear actuator of this embodiment. The horizontal axis shows the moving range of the mover 12 and the vertical axis shows the thrust. In the past, the thrust was changed by the movement of the mover. The maximum thrust is 180N when the mover 12 is at the center (shifted by 0 mm), and the minimum thrust is 40N when the mover is at the left end. That is, the torque ripple 140N is generated for the movement of the movable element 12. In short, depending on the position of the mover, the characteristics of the linear actuator are greatly different, so it is difficult to control, and the linear actuator itself is a vibration source. In this embodiment, the change of the thrust force to the movement of the mover 12 is small, the maximum value is 180N, the minimum value is 160N, and the change is only 20N, so it is a linear actuator that is easy to control and quiet. In this case, the length of the stator 11 in the z-direction is 80 mm, the length of the magnetic pole teeth T is 20 mm, and the length of the complementary pole CP is 10 mm.

FIG. 6 is a graph showing the relationship between the width of the compensation CP of the linear actuator of the present embodiment and the torque ripple.

The horizontal axis shows the ratio of the complement and the vertical axis shows the ratio of the torque ripple. The ratio of the complementary pole is set to (the length of the complementary pole CP) / (the length of the magnetic pole tooth T) × 100 (%). The ratio of torque ripple is set to (torque ripple) / (maximum thrust) × 100 (%). In the above case, the proportion of forming the complement is 50%, and the proportion of the torque ripple is 11%.

It can be seen that after changing the pole compensation CP with the magnetic pole teeth T fixed, even if the proportion of pole compensation is 10%, the torque ripple can be reduced. In short, even if the amplitude of the complementary CP A wider width also has an effect, and the thrust characteristic of the linear actuator 10 can be fixed without increasing the overall length of the stator 11.

In addition, the complementary electrode is a press-molded product of an electromagnetic steel sheet such as that shown in FIG. 3. When, for example, the width of the complementary CP is 2 mm (equivalent to the above 10%), a commercially available 0.50 mm thick electromagnetic plate is used. If there are more than four steel plates, it is sufficient. In short, it is a linear actuator that has negligible material and processing costs and does not increase costs. For example, the thrust characteristics of the linear actuator 10 can be improved.

FIG. 7 is a contour map showing the magnetic flux density inside the linear actuator of this embodiment. In order to confirm the effect of the complementary CP, the analysis result of the magnetic flux density in the machine is displayed. Since the magnetic beam cannot be visualized, simulation analysis is adopted. For the simulation, a commercially available magnetic field analysis software (JMAG-Designer by JSOL) was used.

Fig. 7 (a) is a model without a complementary CP from the previous example; Fig. 7 (b) is a model with a complement in this embodiment. In order to eliminate differences in analysis conditions such as the number of meshes, the analysis model is unified. In other words, the supplementary part in FIG. 7 (a) is analyzed by changing the material to air (without the complement).

In addition, the contour map shows the shift of -10 mm in FIG. 5, in other words, when the mover 12 of FIG. 4 is at the left end.

In FIG. 7 (a), the magnetic flux density of the ring-shaped portion S of the stator 11 is different from left to right (the portion circled by a circle in the figure). In short, the ring portion S on the side (right side in the figure) where the magnetic flux of the magnetic field is consistent with that of the magnet is magnetically saturated. The magnetic saturation shows that the magnetic flux density distribution in the machine is not uniform.

On the other hand, the magnetic flux density in the ring-shaped portion S of the stator 11 in FIG. 7 (b) is almost the same. In addition, it was confirmed that the magnetic flux also passed through the ring portion S of the complement. That is, it was confirmed that the magnetic flux density distribution in the machine was made uniform by the action of the complementary CP.

FIG. 8 is an experimental result of the coil flux of the linear actuator of this embodiment. The horizontal axis shows the moving range of the mover 12, and the vertical axis shows the magnetic flux. When no power is applied (at DC0A), the difference between the previous example and this embodiment is small. However, at the time of energization (at the time of DC1A energization), it can be seen from the previous example that as the displacement advances in the positive direction, it deviates from a straight line and is saturated. On the other hand, in the present invention, the magnetic flux of the coil changes almost linearly in response to the movement of the mover. That is, it means that the characteristics of the linear actuator of the present invention, including the induced voltage, change in almost a certain proportion with the movement of the mover. This means that if you know the position of any mover and the behavior of the linear actuator, you can calculate the correlation. In short, the invented linear actuator does not need to be controlled by the position sensor of the mover. The movement of the mover can be used to estimate the position of the mover from the physical quantity such as the induced voltage. Easy to control linear actuator.

FIG. 9 is a perspective view of the vibration damping device 100 including the linear actuator 10.

The vibration damping device 100 is an electromagnetic suspension provided with the linear actuator 10 and the spring 20 described above, and has a mechanism for suppressing vibration of the outer tank 37 (that is, vibration of the washing machine W: refer to FIG. 11), which is a “vibration target”. Features.

As shown in FIG. 9, one end of the mover 12 of the linear actuator 10 is connected to the outer tank 37 of the washing machine W (see FIG. 11), and the other end is connected Connected to the fixed jig J. In addition, although the stator 11 of the linear actuator 10 is not shown, its movement is restricted by other fixed jigs (not shown). Therefore, when the outer tank 37 of the washing machine W is vibrated in the z direction, the movable element 12 also reciprocates in the z direction, and the relative positional relationship between the movable element 12 and the stator 11 is changed.

The spring 20 is a spring that imparts elastic force to the stator 11 and is interposed between the stator 11 and the fixing jig J. As shown in FIG. 9, the movable element 12 penetrates the stator 11 and also penetrates the spring 20.

FIG. 10 is a perspective view of a washing machine W including the vibration damping device 100.

Since the vibration damping device 100 is provided inside the washing machine W (see FIG. 11), the vibration damping device 100 is not shown in FIG. 10.

The washing machine W shown in FIG. 10 is a drum-type washing machine and has a function of drying clothes. The washing machine W includes the aforementioned vibration damping device 100 (see FIG. 11), a base 31, a housing 32, a door 33, an operation and display panel 34, and a drain pipe H.

The base 31 is a thing supporting the casing 32.

The casing 32 includes left and right side plates 32a, 32a, a front cover plate 32b, a rear cover plate 32c (see FIG. 11), and an upper cover plate 32d. In the vicinity of the center of the front cover 32b, a circular input port h1 (see FIG. 11) for inputting and taking out clothes is formed.

The door 33 is an openable and closable cover provided in the input port h1.

The operation and display panel 34 is a panel provided with an electric switch, an operation switch, and a display, and is provided on the upper cover 32d.

The drain pipe H is for draining the washing water from the outer tank 37 (see FIG. 11). A water pipe is connected to the outer tank 37.

FIG. 11 is a longitudinal sectional view of a washing machine W including the vibration damping device 100.

The washing machine W includes a washing tub 35, a pallet 36, an outer tub 37, a driving mechanism 38, and a blower unit 39 in addition to the aforementioned configuration.

The washing tub 35 is a container for storing clothes, and has a bottomed cylindrical shape. The washing tub 35 is enclosed in the outer tub 37 and is supported on the shaft freely and coaxially with the outer tub 37. The peripheral wall and the bottom wall of the washing tub 35 are provided with a plurality of through holes (not shown) for water supply and ventilation. The opening h2 of the washing tub 35 is adjacent to the closed door 33 together with the opening h3 of the outer tub 37.

In addition, in the example shown in FIG. 11, the rotation central axis of the washing tub 35 is inclined so that the open side becomes higher, but it is not limited to this. That is, the central axis of rotation of the washing tub 35 may be a horizontal direction or a vertical direction.

The supporting plate 36 is an object that lifts and drops laundry during washing and drying, and is provided on the inner peripheral wall of the washing tub 35.

The outer tank 37 is a tank for storing washing water and the like, and has a bottomed cylindrical shape. As shown in FIG. 11, the outer tub 37 includes a laundry tub 35 inside. A linear actuator 10 (a stator 11 and a movable element 12) and a spring 20 are provided on the left and right of the outer groove 37, respectively. In addition, one of the left and right linear actuators 10 is shown in FIG. 11.

A drain hole (not shown) is provided in the lowermost part of the bottom wall of the outer groove 37, and a drain pipe H is connected to the drain hole. Next, a drain valve (not shown) provided in the drain pipe H keeps the laundry water in a closed state. The tank 37 also discharges the washing water by opening the drain valve.

The driving mechanism 38 is a mechanism that rotates the washing tub 35 and is provided outside the bottom wall of the outer tub 37. The rotation shaft of the motor 38 b (see FIG. 7) included in the drive mechanism 38 penetrates 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 to the washing tub 35 and is arranged on the upper side of the washing tub 35. The air blowing unit 39 includes a heater (not shown) and a fan (not shown). Then, the air heated by the heater is sent to the washing tub 35 by a fan. Thereby, the laundry containing water is dry in the washing tub 35 slowly.

FIG. 12 is a configuration diagram of the vibration damping device 100. In FIG. 12, one of the left and right linear actuators 10 is illustrated, and the other is omitted. The vibration damping object G shown in FIG. 12 is an outer tank 37 (see FIG. 11) of the washing machine W (see FIG. 11).

The vibration damping device 100 includes an inverter 40, a current detector 50, and a thrust adjustment unit 60 in addition to the aforementioned configuration (the linear actuator 10 and the spring 20: see FIG. 9).

The inverter 40 converts the DC voltage applied by the rectifier circuit F into a single-phase AC voltage according to the voltage command V * from the thrust adjustment unit 60, and applies the single-phase AC voltage to the winding of the linear actuator 10. 11b (see Fig. 2). In short, the inverter 40 has a function of driving the linear actuator 10 according to the aforementioned voltage command V *.

A “DC power supply” that applies a DC voltage to the inverter 40 includes an AC power supply E and a rectifier circuit F.

FIG. 13 is a configuration diagram including an inverter 40 included in the vibration damping device 100.

13, the linear actuator on the left is referred to as “linear actuator 10L”, and the linear actuator on the right is referred to as “linear actuator 10R”.

The rectifier circuit F shown in FIG. 13 is a conventional voltage doubler rectifier circuit that converts an AC voltage applied from an AC power source E into a DC voltage. As shown in FIG. 7, the rectifier circuit F includes a diode bridge circuit F1 in which diodes D1 to D4 are bridged, and two smoothing capacitors C connected in series.

Next, the voltage (DC voltage including the pulse current) applied by the diode bridge circuit F1 is smoothed by the smoothing capacitor C to generate a DC voltage that is approximately twice the voltage of the AC power source E.

The rectifier circuit F is connected to the inverter 40 through the wiring k1 on the positive side and the wiring k2 on the negative side, and is also connected to the inverter 38a of the drive mechanism 38 that rotates the washing tub 35 (see FIG. 10). The drive mechanism 38 includes an inverter 38a and a motor 38b.

The inverter 40 converts the DC voltage applied by the aforementioned "DC power source" into a single-phase AC voltage, and applies this single-phase AC voltage to the coils 11b of the linear actuators 10L and 10R (see Fig. 2). Three-phase full-bridge inverter.

As shown in FIG. 13, the inverter 40 has a configuration in which the first branch including the switching elements SW1 and SW2, the second branch including the switching elements SW3 and SW4, and the third branch including the switching elements SW5 and SW6 are connected in parallel. . As these switching elements SW1 to SW6, for example, an IGBT (Insulated Gate Bipolar Transistor) can be used.在 开关 Element In the switching element SW1 to SW6 are respectively connected in reverse parallel to the return diodes D.

The connection points of the switching elements SW1 and SW2 are connected to the winding wire 11b of the linear actuator 10L through the wiring k3 (see FIG. 2). In short, the three-phase inverter 40 has a leg corresponding to one phase, and is connected to the left (one) linear actuator 10L.

The connection points of the switching elements SW5 and SW6 are connected to the winding wire 11b of the linear actuator 10R through the wiring k5 (see FIG. 2). In short, the three-phase inverter 40 corresponds to the other branches of one phase, and is connected to the linear actuator 10R on the right side (the other side).

The connection point of the switching elements SW3 and SW4 is connected to the winding wire 11b (see FIG. 2) of the linear actuator 10L through the wiring k4, and is also connected to the winding wire 11b of the linear actuator 10R through the wiring k4. . In short, the remaining branches of the 3-phase inverter 40 are connected to the linear actuator 10L on the left (one side) and the linear actuator 10R on the right (the other side).

In this way, instead of providing the inverters corresponding to the left and right linear actuators 10L and 10R, the left and right are used as one inverter 40 in common, and the cost of the inverter 40 can be reduced. Next, a single-phase AC voltage is applied to the coils 11b (see FIG. 2) of the linear actuators 10L and 10R by controlling the switching elements SW1 to SW6 to be turned on and off according to PWM control (Pulse Width Modulation). .

The current detector 50 is a device that detects a current applied to the linear actuators 10L and 10R, and is provided on the wiring k4. In short, the current detector 50 detects the current flowing to the winding wires 11 b (see FIG. 2) of the linear actuators 10L and 10R.

Although not shown, the thrust adjustment unit 60 shown in FIG. 6 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). Memory), various interfaces and other electronic circuits. Then, the program stored in the ROM is read out and expanded into the RAM, and the CPU executes various processes.

The thrust adjustment unit 60 has a function of adjusting the thrust of the linear actuator 10 by driving the inverter 40 based on the current i detected by the current detector 50. In short, the thrust adjustment unit 60 generates a specific voltage command V * based on the current i described above, and switches on / off of the switching elements SW1 to SW6 based on the voltage command V *. The details will be described later, but if the relative position of the mover 12 and the stator 11 changes with the vibration of the outer groove 37 (see FIG. 5), the thrust adjustment unit 60 adjusts the thrust of the linear actuator 10 so as to offset the change. .

Here, the vibration of the outer tub 37 (that is, the vibration of the washing machine W) will be briefly described. During washing, rinsing, and drying, the driving mechanism 38 shown in FIG. 5 is used to rotate the washing tub 35 at a low speed, and the laundry accumulated on the bottom of the washing tub 35 is repeatedly lifted and tumbling with the support plate 36. . In addition, during the spin-drying, the washing tub 35 is rotated at a high speed, and the spin-drying is performed by the centrifugal force formed by the spin to spin out the moisture of the clothes.

Moreover, in the conventional washing machine, when washing, rinsing, and drying, the vibration of the washing tub 35 often increased due to the reaction force of the dropped laundry. In addition, in the conventional washing machine, vibration and noise were often generated in the washing machine W due to the uneven distribution of the clothes during dehydration. Such as Therefore, in addition to the amount of clothes in the washing tub 35, the partial cloth, and the moisture content, the vibration mode of the washing machine W is constantly changing according to different conditions such as washing, rinsing, drying, and dehydration. Its vibration is transmitted to the outer groove 37.

<Effect>

According to the first embodiment, the thrust adjustment unit 60 generates a thrust based on the current i flowing to the linear actuator 10 so as to cancel the vibration of the outer groove 37. Accordingly, the vibration damping device 100 can appropriately suppress the vibration of the outer groove 37 in a relatively simple manner.

In addition, according to the first embodiment, it is not necessary to provide a position sensor that detects the position of the movable element 12, so that the cost of the washing machine W can be reduced. In addition, the linear actuator 10 hardly suffers damage or abrasion of its constituent elements (the stator 11 and the mover 12), so that the durability of the vibration damping device 100 can be improved.

The single-phase AC voltage applied to the left and right linear actuators 10L and 10R (see FIG. 13) is generated by one inverter 40. Therefore, the cost of the washing machine W can be reduced compared to a configuration in which inverters are provided for the left and right linear actuators 10L and 10R, respectively.

In addition, by using ytterbium-iron-nitrogen-based permanent magnets 121b, 122b, and 123b (see FIG. 1), as described above, compared with the previous technology using neodymium magnets, it is possible to achieve low cost of permanent magnets 121b, 122b, and 123b. Into. Therefore, the manufacturing cost of the washing machine W can be reduced.

变形 Modification of the first implementation type≫

In the first embodiment, it is explained that the current ratio gain Kp of the thrust adjustment unit 60 is constant, but the viscosity coefficient C [Ns / m of the linear actuator 10 can also be changed by changing the current ratio gain Kp. 〕. A method of changing this viscosity coefficient C will be described below.

The equation of motion of the vibration damping device 100 of the electromagnetic hanger is expressed by the following mathematical formula (1). In addition, F _D [N] represented by the mathematical formula (1) is a force generated by the vibration damping device 100 (that is, a thrust force of the linear actuator 10). In addition, x [m] is the position of the mover 12.

In addition, the equation of motion of the thrust of the linear actuator 10 is expressed by mathematical formula (2). In addition, F _L [N] is a thrust of the linear actuator 10, and K _e [N / A] is a motor constant of the linear actuator 10. In addition, I [A] is a current flowing to the winding wire 11b (see FIG. 2), and V [V] is a voltage applied to the winding wire 11b. In addition, R [Ω] is the resistance of the coil 11b, [T] is a magnetic flux generated on the winding wire 11b.

Here, the force F _{D of the} formula (1) is equivalent to the thrust F _L of the formula (2), so the following formula (3) is derived. C [N · m / rad] is a viscosity coefficient of the linear actuator 10.

FIG. 14A is a comparative example using an oil damper having a constant viscosity coefficient C, and shows the experimental results of changes in the rotation speed of the washing tub 35 and the displacement (vibration) of the outer tub 37.

In the experiment of FIG. 14A, the laundry tank 35 was rotated while 1 kg of laundry was placed in a specific position off-center in the laundry tank 35 (the same is true for FIG. 14B).

As shown in FIG. 14A, as the rotation speed of the washing tub 35 becomes larger, the amplitude of the outer tub 37 changes. Specifically, when the rotation speed of the washing tub 35 is increased from zero, the amplitude of the outer tub 37 at a rotational speed of about 50 [min ^-1 ] is reduced by one degree, and the outer tub 37 is about 100 [min ^-1 ] at a rotational speed. The amplitude rapidly increases to the maximum amplitude. In addition, at a rotation speed of 105 to 170 [min ^-1 ], the amplitude of the outer tub 37 increases. In a region above 200 [min ^-1 ], as the rotation speed of the laundry tub 35 increases, the amplitude of the outer tub 37 changes. small.

FIG. 14B shows the experimental results of changes in the rotation speed of the washing tub 35 and the displacement (vibration) of the outer tub 37 in the second embodiment.

In the experiment shown in FIG. 14B, the larger the rotation speed of the washing tub 35 (that is, the higher the vibration frequency f of the outer tub 37), the smaller the viscosity coefficient C of the linear actuator 10.

As shown in FIG. 14B, when the rotation speed of the washing tub 35 is about 100 [min ^-1 ], the maximum amplitude of the outer tub 37 is about 5 mm, which is half the maximum vibration (about 10 mm) of the comparative example shown in FIG. degree. In a region where the rotation speed of the washing tub 35 is 500 [min ^-1 ] or more, the amplitude of the outer tub 37 becomes approximately 1 mm. As described above, according to the second embodiment, by controlling the viscosity coefficient C variably, it is possible to more effectively suppress the vibration of the outer groove 37 than in the first embodiment.

In addition, in each embodiment, the configuration in which the spring 20 is provided between the stator 11 (see FIG. 9) and the fixing jig J has been described, but it is not limited thereto. For example, instead of the spring 20, a mechanism using rubber or hydraulic pressure may be applied.

In addition, in each embodiment, the configuration in which the movable element 12 is connected to the outer groove 37 that is a vibration damping object has been described, but is not limited thereto. In other words, one of the stator 11 and the movable element 12 may be connected to a vibration damping object, and the relative position of the stator 11 and the movable element 12 may be changed by using magnetic attraction and repulsion.

In addition, in each of the embodiments, the configuration in which the washing machine W is damped by the vibration damping device 100 or the like has been described, but it is not limited thereto. For example, in addition to home appliances such as air conditioners and refrigerators, various embodiments may be applied to railway vehicles and automobiles.

In addition, in each embodiment, the configuration is described in which the linear actuator 10 is driven by single-phase AC power, but the linear actuator 10 may be driven by, for example, three-phase AC power.

In addition, the embodiment is described in detail in order to make the present invention easy to understand, but is not limited to having all the structures described above. In addition, part of the structure of the implementation type is traced to other structures. Addition, deletion, and replacement are possible.

In addition, the aforementioned institutions or structures are only those deemed necessary in the description, and are not limited to all the institutions or structures that must be included in the product.

Claims (6)

A linear actuator including a stator and a mover moving opposite to the stator, characterized in that the stator has a field coil, the mover has a permanent magnet, and a complement is provided between magnetic teeth wound in the field coil. ; In the moving range of the movable element, the magnetic pole of the permanent magnet facing the complementary pole is fixed; the length T _L of the magnetic tooth portion in which the field coil is wound is compared with the movable range of the linear actuator X is longer; the length M _{L of the} permanent magnet is larger than the tooth pitch T _{P of the} magnetic teeth. A vibration damping device comprising: a linear actuator described in item 1 of a patent application scope; the linear actuator is connected to an object to be damped and an inverter that drives the linear actuator is detected; A current detector that is energized to the current of the linear actuator, and a thrust adjustment unit that adjusts the thrust of the linear actuator by driving the inverter based on the current detected by the current detector. For example, the vibration damping device described in the second item of the patent application scope includes a pair of the aforementioned linear actuators driven by single-phase AC power, and the aforementioned inverter is a 3-phase full-bridge inverter corresponding to the aforementioned 3-phase One-phase branch of the full-bridge inverter is connected to one of the aforementioned linear actuators, and the other branch corresponding to one phase of the aforementioned 3-phase full-bridge inverter is connected to one and the other The aforementioned linear actuator. For example, the vibration damping device described in item 2 of the scope of the patent application, wherein the aforementioned permanent magnet of the aforementioned linear actuator is a rhenium (Sm) -iron-nitrogen-based permanent magnet. The vibration damping device described in item 2 of the patent application scope, which has the aforementioned linear actuator and elastic body. A washing machine is characterized in that it comprises a laundry tub for accommodating clothes, an outer tub including the aforementioned laundry tub, a driving mechanism for rotating the aforementioned laundry tub, and an application patent scope item 1 connected to the aforementioned outer tub, which is a vibration damping object The linear actuator includes a stator and a mover that is opposed to the stator and moves. The stator has a field coil, the mover has a permanent magnet, and is provided between magnetic teeth wound in the field coil. Complement: In the moving range of the movable element, the magnetic pole of the permanent magnet facing the complement is fixed.