Actuator

Abstract

A large acceleration is obtained on a wide frequency band, and collision between a movable body and a supporting body is avoided. The actuator (1) selects a viscoelastic body having a high attenuation coefficient as a connecting body (9) connecting the movable body (3) and the support body (2), thereby obtaining an acceleration equal to or greater than a target acceleration At (e.g., At = 2.5 Gal) within a target frequency band (e.g., 50 Hz to 100 Hz inclusive). A control unit (1A) of an actuator (1) sets a voltage at which a target acceleration At can be obtained within a target frequency band as a first voltage VH, and supplies a current of the first voltage VH as long as the amplitude of a movable body (3) does not exceed an upper limit amplitude Wmax, thereby enabling a large acceleration to be obtained. On the other hand, in a frequency band in which the amplitude of the movable body (3) exceeds the upper limit amplitude Wmax when the movable body (3) is driven at the first voltage VH, the movable body (3) is prevented from colliding with the support body (2) by making the voltage of the drive current lower than the first voltage VH.

Description

Technical Field

[0001] The present invention relates to an actuator for vibrating a movable body. Background Art

[0002] Patent Document 1 describes an actuator comprising: a support body and a movable body; a connector connecting the movable body to the support body; and a magnetic drive circuit for moving the movable body relative to the support body. The magnetic drive circuit comprises: a magnet mounted on one of the movable body and the support body; and a coil mounted on the other of the movable body and the support body. The magnet faces the coil in a direction perpendicular to the vibration direction. The connector is a viscoelastic material such as silicone.

[0003] The actuator disclosed in Patent Document 1 can be incorporated into, for example, a gaming console's operating components or operating panel, and used as a haptic device that provides a user with a sense of touch through the vibration of a movable body. In this case, the user experiences vibrations with an intensity corresponding to the weight and acceleration of the movable body. Conventionally, such actuators achieve high acceleration by setting the frequency of the drive current supplied to the coil near the resonant frequency. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2019-013094 Summary of the Invention

[0005] Technical problem to be solved by the invention When using an actuator as a haptic device, it is necessary to achieve high acceleration across a wide frequency band, not just near the resonant frequency, to ensure that the tactile sensation experienced by the user matches various needs. The inventors, noting that changing the type of viscoelastic material alters its properties (spring and viscous elements), attempted to increase the acceleration across a wide frequency band by adding viscous elements. However, this approach resulted in an excessively large maximum amplitude, which could cause the movable body to collide with the supporting body.

[0006] In view of the above problems, an object of the present invention is to provide an actuator that can obtain a large acceleration over a wide frequency band and can prevent a movable body from colliding with a supporting body. Technical solutions used to solve technical problems

[0007] In order to solve the above-mentioned problem, an actuator of one embodiment of the present invention comprises: a supporting body and a movable body; a connecting body connected to the movable body and the supporting body; a magnetic drive circuit for causing the movable body to vibrate relative to the supporting body; and a control unit for controlling the drive current supplied to the magnetic drive circuit, wherein the connecting body is a viscoelastic body, the maximum amplitude of the movable body that does not collide with the supporting body is set as an upper limit amplitude, the frequency at which the acceleration or amplitude of the movable body is maximum when the voltage of the drive current is set to a constant value is set as a peak frequency, the acceleration of the movable body reaches a predetermined target acceleration or above in a target frequency band including the peak frequency, and the movable body The voltage when the amplitude exceeds the upper limit amplitude at the peak frequency is set to the first voltage, and in the case where the frequency band in which the amplitude of the movable body becomes above the upper limit amplitude when the voltage of the driving current is set to the first voltage is a mid-frequency band from a first frequency lower than the peak frequency to a second frequency higher than the peak frequency, when driving in a low frequency band below the first frequency and a high frequency band above the second frequency, the control unit sets the voltage of the driving current to the first voltage, and when driving in the mid-frequency band, the control unit sets the voltage of the driving current to a voltage lower than the first voltage and at which the amplitude of the movable body becomes below the upper limit amplitude.

[0008] According to this method, it is possible not only to increase the acceleration of the movable body at frequencies near the peak frequency, but also to increase the acceleration of the movable body within a wider frequency range. That is, the voltage capable of obtaining the target acceleration in the target frequency band is set to the first voltage, and as long as the amplitude of the movable body does not exceed the upper limit amplitude, a current of the first voltage is provided, thereby enabling a greater acceleration to be obtained. On the other hand, in a frequency band where the amplitude of the movable body exceeds the upper limit amplitude when driven by the first voltage, the voltage of the driving current is made lower than the first voltage, thereby avoiding collision between the movable body and the supporting body. Thus, it is possible to provide an actuator that can obtain the target acceleration in the target frequency band as desired and can avoid collision between the movable body and the supporting body.

[0009] Conventional actuator designs achieve high acceleration by driving the movable body at frequencies near its peak frequency. However, the inventors realized that by adjusting the properties of the viscoelastic material used as the connector and using a viscoelastic material with increased viscosity, acceleration could be increased over a wider frequency band. This led to the following technical concept: by reducing the voltage near the peak frequency to prevent the movable body from vibrating excessively and thus colliding with the supporting body, high acceleration can be achieved over a wide frequency band.

[0010] In this embodiment, when driving at a frequency in the mid-frequency band, the control unit preferably sets the voltage of the driving current to a voltage that causes the amplitude of the movable body to coincide with the upper limit amplitude. This maximizes the acceleration of the movable body, thereby increasing the vibration felt by the user.

[0011] In this aspect, as the peak frequency, an acceleration peak frequency at which the acceleration of the movable body reaches a maximum when the voltage of the drive current is set to a constant value may be used.

[0012] In this embodiment, the target frequency band can be set to 50 Hz or more and 100 Hz or less. Thus, by performing voltage control as in this embodiment, the target acceleration can be obtained in a wider range, not just at frequencies near the peak frequency.

[0013] In this embodiment, when driving at a frequency within the range from the first frequency to the peak frequency, the control unit preferably reduces the voltage of the drive current as the frequency increases. When driving at the peak frequency, the control unit sets the voltage of the drive current to a voltage that causes the amplitude of the movable body to coincide with the upper limit amplitude. When driving at a frequency within the range from the peak frequency to the first frequency, the control unit preferably increases the voltage of the drive current as the frequency increases. In this manner, by adopting a voltage pattern in which the voltage is lowest at the peak frequency, the acceleration of the movable body can be caused to exceed the target value over a wide range.

[0014] In this embodiment, the magnetic drive circuit preferably includes a coil and a magnet that is opposed to the coil in a first direction, and causes the movable body to vibrate relative to the support body in a second direction intersecting the first direction. The viscoelastic body is arranged at a position relative to the support body and the movable body in the first direction, with the first direction being the thickness direction. When the movable body moves relative to the support body in the second direction, the viscoelastic body deforms in a shear direction. In such a structure, by adjusting the characteristics of the viscoelastic body, the acceleration of the movable body can be increased within a wider frequency band. Therefore, by adjusting the voltage of the drive current, the amplitude of the movable body can be prevented from being too large, thereby avoiding collision between the movable body and the support body.

[0015] In this embodiment, silicone rubber can be used as the viscoelastic body. Effects of the Invention

[0016] According to this method, it is possible not only to increase the acceleration of the movable body at frequencies near the peak frequency, but also to increase the acceleration of the movable body within a wider frequency range. That is, the voltage capable of obtaining the target acceleration in the target frequency band is set to the first voltage, and as long as the amplitude of the movable body does not exceed the upper limit amplitude, a current of the first voltage is provided, thereby enabling a greater acceleration to be obtained. On the other hand, in a frequency band where the amplitude of the movable body exceeds the upper limit amplitude when driven by the first voltage, the voltage of the driving current is made lower than the first voltage, thereby avoiding collision between the movable body and the supporting body. Thus, it is possible to provide an actuator that can obtain the target acceleration in the target frequency band as desired and can avoid collision between the movable body and the supporting body. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a perspective view of the appearance of an actuator according to an embodiment of the present invention. Figure 2 yes Figure 1 XZ cross-sectional view of the actuator. Figure 3 yes Figure 1 YZ cross-sectional view of the actuator. Figure 4 yes Figure 1 Exploded perspective view of the actuator. Figure 5 This diagram illustrates the voltage, amplitude, and acceleration characteristics of an actuator. DETAILED DESCRIPTION

[0018] Below, an embodiment of the actuator 1 of the present invention is described with reference to the accompanying drawings. In the following description, the three intersecting directions are referred to as the first direction Z, the second direction X, and the third direction Y. Furthermore, one side of the second direction X is labeled X1, the other side of the second direction X is labeled X2, one side of the third direction Y is labeled Y1, the other side of the third direction Y is labeled Y2, and one side of the first direction Z is labeled Z1, and the other side of the first direction Z is labeled Z2. In this embodiment, the first direction Z, the second direction X, and the third direction Y are orthogonal to each other. The second direction X is the vibration direction of the movable body 3.

[0019] Figure 1 It is a perspective view of the actuator 1 according to the embodiment of the present invention. Figure 2 yes Figure 1 XZ cross-sectional view of actuator 1. Figure 3 yes Figure 1 YZ cross-sectional view of actuator 1. Figure 4 yes Figure 1 Exploded perspective view of the actuator 1.

[0020] like Figure 1As shown, the actuator 1 is in the shape of a rectangular parallelepiped as a whole, and its dimension in the second direction X is larger than its dimension in the third direction Y and its dimension in the first direction Z. Figure 2 、 Figure 3 、 Figure 4 As shown, actuator 1 includes a support body 2, a movable body 3, a magnetic drive circuit 4, and a wiring substrate 5. Magnetic drive circuit 4 includes a coil 6 and a magnet 7 that face each other in a first direction Z, and vibrates movable body 3 in a second direction X. Coil 6 is connected to wiring substrate 5 fixed to the outer peripheral surface of support body 2, and current flows through coil 6 via wiring substrate 5.

[0021] The actuator 1 includes a connecting body 9 connected to the support body 2 and the movable body 3. The movable body 3 is supported by the support body 2 via the connecting body 9. As described later, the actuator 1 uses a gel-like material (viscoelastic body) as the connecting body 9.

[0022] The actuator 1 vibrates the movable body 3 in the second direction X, thereby notifying the user of information through the body of a person using the actuator 1 or a device in which the actuator 1 is installed. The actuator 1 can be incorporated into, for example, an operating member of a game console, an operating panel, a steering wheel or a seat of an automobile, and can be used as a tactile device that provides a tactile sense to the user by vibrating the movable body 3 in the second direction X.

[0023] The actuator 1 includes a control unit 1A (see Figure 2 ), the control unit 1A controls the drive current supplied to the coil 6 of the magnetic drive circuit 4. The control unit 1A supplies the drive current to the coil 6 through the wiring substrate 5. When the actuator 1 is used as a tactile device, alternating current is supplied to the coil 6 as the drive current. The control unit 1A controls the frequency and voltage of the alternating current, thereby controlling the vibration felt by the user of the actuator. For example, by controlling the combination of the frequency and voltage of the alternating current, the magnitude of the acceleration of the movable body 3 is controlled, thereby controlling the intensity of the vibration felt by the user. In addition, the variation pattern of the alternating current can also be controlled. For example, by making the acceleration of the movable body 3 moving to one side X1 of the second direction X different from the acceleration of the movable body 3 moving to the other side X2 of the second direction X, the user can feel a directional vibration in the second direction X.

[0024] The support body 2 includes a first housing member 10, a coil holder 30, and a second housing member 20, which are stacked in sequence from one side Z1 to the other side Z2 along the first direction Z. The movable body 3 and the magnetic drive circuit 4 are disposed between the first housing member 10 and the second housing member 20. In this embodiment, the first housing member 10, the coil holder 30, and the second housing member 20 are each made of resin.

[0025] like Figure 4As shown, the coil holding member 30 is provided with a convex portion 30a protruding toward the first housing part 10 side and a convex portion 30b protruding toward the second housing part 20 side at the four corners. When the support body 2 is assembled, the convex portion 30a of the coil holding member 30 is fitted into the hole 10a of the first housing part 10, and the convex portion 30b of the coil holding member 30 is fitted into the hole (not shown) of the second housing part 20. Therefore, the first housing part 10, the coil holding member 30 and the second housing part 20 are connected in a state of being positioned with respect to each other. The first housing part 10, the coil holding member 30 and the second housing part 20 are bonded together by, for example, an adhesive. Alternatively, a structure in which the first housing part 10, the coil holding member 30 and the second housing part 20 are held on the inner side of a cylindrical cover not shown can also be adopted.

[0026] The first housing member 10 includes a first end plate portion 11 having two recesses 13 arranged in the second direction X, and a first side plate portion 12 extending from the outer periphery of the first end plate portion 11 in the Z2 direction. The second housing member 20 includes a second end plate portion 21 having two recesses 23 arranged in the second direction X, and a second side plate portion 22 extending from the outer periphery of the second end plate portion 21 in the Z1 direction. Holes 10a for engaging the protrusions 30a of the coil holder 30 are opened on the top surface of the four corners of the first side plate portion 12, and holes (not shown) for engaging the protrusions 30b of the coil holder 30 are opened on the top surface of the four corners of the second side plate portion 22.

[0027] The wiring substrate 5 is fixed to the X2-direction side surface of the coil holder 30. A recess 24 is formed on the X2-direction side surface of the second housing member 20. This recess 24 is used to accommodate the upper end of the wiring substrate 5, which protrudes from the coil holder 30 in the Z2 direction. The coil wire (not shown) extending from the coil 6 is routed along the Z2-direction surface of the coil holder 30 and connected to the wiring substrate 5.

[0028] The coil holder 30 is provided with a first coil placement hole 31 and a second coil placement hole 32 arranged along the second direction X. The first coil placement hole 31 is arranged in the X1 direction, and the second coil placement hole 32 is arranged in the X2 direction relative to the first coil placement hole 31. The coil holder 30 includes a plate portion 33 parallel to the XY plane. The first coil placement hole 31 and the second coil placement hole 32 extend through the plate portion 33 in the first direction Z. A partition 34 is provided between the first coil placement hole 31 and the second coil placement hole 32, extending along the third direction Y. The partition 34 is located approximately at the center of the coil holder 30 in the second direction X.

[0029] The coil holder 30 is formed with a cutout portion 301 in the X1 direction of the first coil arrangement hole 31, and an opening portion 302 in the X2 direction of the second coil arrangement hole 32. The cutout portion 301 and the opening portion 302 penetrate the plate portion 33 in the first direction Z. Recesses 303 and 304 that are recessed in the Y2 direction are provided on the side surface of the plate portion 33 in the Y1 direction. The recess 303 is provided at approximately the center of the second direction X of the plate portion 33, and the recess 304 is provided near the end of the plate portion 33 in the X2 direction. A recess 305 that is recessed in the Y1 direction is provided at approximately the center of the second direction X on the Y2 direction side of the plate portion 33. The recesses 303, 304, 305 are used as wiring space when the coil wire (not shown) is led out from the coil 6 and wired to the wiring substrate 5.

[0030] like Figure 1 As shown, a sealing member 201 is affixed to the outer circumference of the actuator 1 in the X1 direction, sealing the cutout 301 of the coil holder 30. During the manufacturing process of the actuator 1, when the interior is inspected, inspection light is irradiated through the cutout 301. Furthermore, a sealing member 202 is affixed to the outer circumference of the actuator 1 in the Y1 direction, sealing the recesses 303 and 304. A sealing member 203 is affixed to the outer circumference of the actuator 1 in the Y2 direction, sealing the recess 305.

[0031] The support body 2 includes a metal plate 40 that overlaps the plate portion 33 of the coil holder 30 and the coil 6 from the Z1 direction. The plate 40 overlaps the first coil placement hole 31 and the second coil placement hole 32, but does not overlap the cutout portion 301 and the opening 302. When the coil 6 is fixed to the coil holder 30, the plate 40 and the coil holder 30 are stacked, and the coil 6 is placed and fixed in the first coil placement hole 31 and the second coil placement hole 32 filled with adhesive.

[0032] like Figure 4 As shown, the coil holder 30 includes two spring portions 50 that press the outer circumference of the coil 6 to position the coil 6. The spring portion 50 is a resin spring formed integrally with the coil holder 30. The spring portion 50 is provided on the inner circumference of the first coil arrangement hole 31 in the X2 direction and on the inner circumference of the second coil arrangement hole 32 in the X1 direction.

[0033] The coil holder 30 is provided with receiving portions 55 at two locations spaced apart along the third direction Y on the inner circumference of the first coil arrangement hole 31 in the X1 direction and the inner circumference of the second coil arrangement hole 32 in the X2 direction. The first coil 61 is pressed in the X1 direction by the spring portion 50 within the first coil arrangement hole 31 and against the receiving portion 55. The second coil 62 is pressed in the X2 direction by the spring portion 50 within the second coil arrangement hole 32 and against the receiving portion 55. Therefore, the first coil 61 and the second coil 62 are both in contact with the effective side 601 via the receiving portions 55 at two locations and the spring portion 50 at one location, thereby being supported at three points.

[0034] The spring portion 50 is disposed on the side surface of the partition portion 34 in the X1 direction and the side surface of the partition portion 34 in the X2 direction, which are disposed at the center of the coil holder 30 in the second direction X. A recessed portion 35 is provided on the side surface of the partition portion 34 in the X1 direction, recessed in the X2 direction. The spring portion 50 extends from the opening edge of the recessed portion 35 in the Y1 direction toward the opening edge in the Y2 direction. A recessed portion 36 is provided on the side surface of the partition portion 34 in the X2 direction, recessed in the X1 direction. The spring portion 50 extends from the opening edge of the recessed portion 36 in the Y2 direction toward the opening edge in the Y1 direction. Therefore, the spring portion 50 is elastically deformable in the second direction X.

[0035] A convex portion 51 protruding toward the side where the coil 6 is located is provided at the front end of each spring portion 50. The front end of the convex portion 51 protrudes from the inner circumference of each coil configuration hole toward the inner circumference. Therefore, the spring portion 50 presses the coil 6 with the front end of the convex portion 51. Each spring portion 50 also has a locking portion 52 protruding from the end of the convex portion 51 in the Z2 direction. The locking portion 52 locks the outer circumference of the first coil 61 in the X2 direction from the Z2 direction. Similarly, the locking portion 56 protruding from the end of the receiving portion 55 in the Z2 direction locks the outer circumference of the first coil 61 in the X1 direction from the Z2 direction. Thus, the first coil 61 is held so as not to fall out of the first coil configuration hole 31. Similarly, in the second coil configuration hole 32, the second coil 62 is held so as not to fall out of the second coil configuration hole 32.

[0036] The magnetic drive circuit 4 includes a first coil 61 and a second coil 62 as the coil 6. The first coil 61 is disposed in the first coil arrangement hole 31. The second coil 62 is disposed in the second coil arrangement hole 32. The coil 6 is an oblong air-core coil having two effective sides 601 extending along the third direction Y. A central hole 602 extending along the third direction Y is provided in the center of the coil 6.

[0037] Magnet 7 is opposite to the effective side 601 of coil 6 in a first direction Z. Magnet 7 includes two first magnets 71 and 72 facing the effective sides 601 of first and second coils 61 and 62 from the Z1 direction; and two second magnets 73 and 74 facing the effective sides 601 of first and second coils 61 and 62 from the Z2 direction. The first magnets 71 and 72 and the second magnets 73 and 74 are polarized and magnetized along a third direction Y. In this embodiment, the first coil 61 and the second coil 62 are identical. Furthermore, the first magnets 71 and 72 and the second magnets 73 and 74 are identical magnets.

[0038] In this embodiment, the magnets 7 are positioned on both sides of the coil 6 in the first direction Z. However, the magnetic drive circuit 4 may also employ a configuration in which the magnets 7 are positioned only on one side of the coil 6 in the Z1 and Z2 directions. Furthermore, in this embodiment, two sets of magnetic drive circuits 4 are provided, with the coils 6 and magnets 7 facing each other in the first direction Z. However, the present invention is applicable to actuators having a single set of magnetic drive circuits 4 or three or more sets of magnetic drive circuits 4.

[0039] The movable body 3 includes a yoke 80 for holding the magnet 7. Figure 2 、 Figure 3 and Figure 4 As shown, the yoke 80 includes: a first plate portion 81, which faces the plate portion 33 of the coil holder 30 from the Z1 direction; a second plate portion 82, which faces the plate portion 33 from the Z2 direction; and a pair of connecting plate portions 83, 84, which extend along the first direction Z on both sides of the third direction Y of the plate portion 33 to connect the first plate portion 81 and the second plate portion 82. The first magnets 71 and 72 are fixed to the surface of the first plate portion 81 in the Z2 direction and arranged in the second direction X. The second magnets 73 and 74 are fixed to the surface of the second plate portion 82 in the Z1 direction and arranged in the second direction X. The first magnets 71 , 72 and the second magnets 73 , 74 are fixed to the yoke 80 by bonding or the like.

[0040] The yoke 80 is composed of two parts, a first yoke 85 and a second yoke 86, joined together. The first yoke 85 includes a first plate portion 81 and a pair of connecting plate portions 83 and 84 bent from opposite ends of the first plate portion 81 in the third direction Y in the Z2 direction. The second yoke 86 is composed of a second plate portion 82. The connecting plate portion 83 extends in the Z2 direction through the cutout 301 of the coil holder 30 in the X1 direction relative to the first coil 61. The connecting plate portion 84 extends in the Z2 direction through the opening 302 of the coil holder 30 in the Z2 direction relative to the second coil 62. The ends of the pair of connecting plate portions 83 and 84 in the Z2 direction are connected to the ends of the second plate portion 82 in the third direction Y by welding.

[0041] (Connector) like Figure 2 As shown, the connector 9 is disposed at a position where the support body 2 and the movable body 3 are opposed in the first direction Z. The movable body 3 is supported by the connector 9 so as to be movable in the second direction X. In this embodiment, the connector 9 includes a first connector 91 disposed at a position where the first magnetic yoke 85 and the first housing member 10 are opposed in the first direction Z; and a second connector 92 disposed at a position where the second magnetic yoke 86 and the second housing member 20 are opposed in the first direction Z.

[0042] The first connector 91 is disposed in a compressed state between the first plate portion 81 of the first magnetic yoke 85 and the bottom surface of the recess 13 of the first housing member 10 in the first direction Z. In this embodiment, the two first connectors 91 are arranged side by side along the second direction X. Furthermore, the second connector 92 is disposed in a compressed state between the second plate portion 82 of the second magnetic yoke 86 and the bottom surface of the recess 23 of the second housing member 20 in the first direction Z. In this embodiment, the two second connectors 92 are arranged side by side along the second direction X.

[0043] In the present embodiment, the connector 9 is a viscoelastic body. For example, the connector 9 (viscoelastic body) is a silicone with a needle penetration of 10 to 110 degrees. The needle penetration is defined in JIS-K-2207 and JIS-K-2220, and the smaller the value, the harder the material. The viscoelastic properties of silicone are not limited to the above-mentioned properties. For example, as described below, silicone with a high viscosity component and a high attenuation coefficient can be used. In addition, the connector 9 with viscoelasticity can use various rubber materials and modified materials such as natural rubber, diene rubber (for example, styrene-butadiene rubber, isoprene rubber, butadiene rubber), chloroprene rubber, acrylonitrile-butadiene rubber, etc.), non-diene rubber (for example, butyl rubber, ethylene propylene rubber, EPDM rubber, polyurethane rubber, silicone rubber, fluororubber, etc.), thermoplastic elastomer, etc.

[0044] The connector 9 has linear or nonlinear expansion and contraction characteristics depending on its expansion and contraction direction. For example, when the connector 9 is compressed and deformed in its thickness direction (axial direction), it has an expansion and contraction characteristic in which the nonlinear component (viscous component) is greater than the linear component (spring component). In contrast, when stretched in the thickness direction (axial direction), it has an expansion and contraction characteristic in which the linear component (spring component) is greater than the nonlinear component (viscous component). In addition, when the connector 9 is deformed in a direction (shear direction) that intersects the thickness direction (axial direction), regardless of the direction of movement, the deformation is along the stretching direction, and therefore, it has a deformation characteristic in which the linear component (spring component) is greater than the nonlinear component (viscous component).

[0045] When the movable body 3 vibrates in the second direction X, the connecting body 9 deforms in the shear direction. Therefore, when the movable body 3 vibrates in the second direction X, the deformation characteristics of the connecting body 9 in the shear direction can be utilized to improve the reproducibility of the vibration acceleration relative to the input signal, thereby achieving subtle vibration.

[0046] (Selection of viscoelastic material and voltage characteristics used for drive control) Figure 5 It is an explanatory diagram of the voltage characteristic, amplitude characteristic, and acceleration characteristic of the actuator 1 . Figure 5 (a) is a graph of voltage characteristics, Figure 5 (b) is a graph of amplitude characteristics. Figure 5 (c) is a graph of acceleration characteristics. Figure 5 In (a) to (c), the voltage characteristic V, amplitude characteristic W, and acceleration characteristic A shown by solid lines represent the characteristics of the actuator 1 according to the present embodiment. The voltage characteristic V1, amplitude characteristic W1, and acceleration characteristic A1 shown by dashed lines represent the characteristics of Comparative Example 1. The voltage characteristic V2, amplitude characteristic W2, and acceleration characteristic A2 shown by double-dashed lines represent the characteristics of Comparative Example 2.

[0047] Figure 5 The amplitude characteristics W, W1, W2 and Figure 5 The acceleration characteristics A, A1, and A2 shown in (c) can be obtained as solutions to the equation of motion for a vibration system with one degree of freedom, based on the weight of the movable body 3, the viscoelastic properties of the connector 9 (spring element + damping element), and the Lorentz force of the magnetic drive circuit (i.e., the thrust that causes the movable body 3 to vibrate). Therefore, once the specific structure of the actuator 1 is determined, the amplitude characteristics W, W1, and W0, as well as the acceleration characteristics A, A1, and A2, can be obtained from the equation of motion using the voltage characteristics V, V1, and V2 as parameters. Alternatively, the prototype movable body 3 can be driven using the voltage characteristics V, V1, and V2, and then measured to determine the amplitude characteristics W, W1, and W2 and the acceleration characteristics A, A1, and A2.

[0048] In this embodiment, the viscoelastic properties (spring element + damping element) of connector 9, one of the parameters defining acceleration characteristics A, A1, and A2, are considered. The type of viscoelastic material used in connector 9 is selected so as to achieve an acceleration greater than or equal to the target acceleration At (e.g., At = 2.5 Gal) within the target frequency band desired by the actuator user (e.g., 50 Hz to 100 Hz). The selection of a viscoelastic material is based on the fact that using a viscoelastic material with a high damping coefficient shifts the overall acceleration level to a higher level across a wider frequency band.

[0049] The characteristics of Comparative Example 1 are obtained when the actuator 1 is constructed using a viscoelastic body selected to satisfy the above conditions and driven at the first voltage VH (VH = 5.9V) in all frequency bands. In other words, the voltage characteristics of Comparative Example 1 are "no voltage control" in the entire frequency band. Figure 5 As shown in (c) of FIG. 1 , when the voltage of the driving current is kept constant, the frequency at which the acceleration of the movable body 3 reaches the maximum acceleration is defined as the peak frequency fp. Figure 5 As shown in (b) of FIG. 1 , the amplitude of the movable body 3 reaches a maximum amplitude at or near the peak frequency fp.

[0050] It can be seen from the amplitude characteristic W1 of Comparative Example 1 that when driven with the first voltage VH within the entire frequency band, the amplitude of the movable body 3 exceeds the upper limit amplitude Wmax of the actuator 1 of this embodiment in the intermediate frequency band from the first frequency f1 to the second frequency f2. The upper limit amplitude Wmax is the maximum amplitude at which the movable body 3 in the actuator 1 of this embodiment can vibrate without colliding with the support body 2. The maximum amplitude is determined by the minimum gap between the parts of the movable body 3 and the support body 2 that are opposite to each other in the second direction X. For example, in this embodiment, the upper limit amplitude Wmax is set to 1.3 mm. In addition, the upper limit amplitude Wmax does not have to be consistent with the maximum amplitude. Taking into account the amplitude disturbance caused by external interference, etc., it can be set to a value smaller than the maximum amplitude.

[0051] In this embodiment, in the intermediate frequency band from the first frequency f1 to the second frequency f2, the voltage characteristic V is set so that the voltage of the drive current becomes a value lower than the first voltage VH (see Figure 5 (a)). That is, the voltage characteristics of this embodiment are such that the mid-frequency band from the first frequency f1 to the second frequency f2 is set as the voltage control zone, the voltage control zone is set to "voltage control", and the other zones are set to "no voltage control (i.e., the voltage is constant)." This prevents the amplitude of the movable body 3 from exceeding the upper limit amplitude Wmax in the mid-frequency band from the first frequency f1 to the second frequency f2.

[0052] More specifically, in the frequency band from the first frequency f1 to the peak frequency, a characteristic is adopted in which the voltage decreases as the frequency increases. On the other hand, in the frequency band from the peak frequency to the second frequency f2, a characteristic is adopted in which the voltage increases as the frequency increases. The curve shape of the voltage characteristic is set so that the amplitude of the movable body 3 coincides with the upper limit amplitude Wmax at all frequencies in the mid-frequency band from the first frequency f1 to the second frequency f2.

[0053] As a result, compared to the acceleration characteristic A1 of Comparative Example 1, which did not perform voltage reduction control, the acceleration characteristic A in the mid-frequency band from the first frequency f1 to the second frequency f2 shows a more gradual increase in acceleration with increasing frequency within the range from the first frequency f1 to the second frequency f2, and the peak acceleration is also lower. Furthermore, the frequency at which the peak acceleration is achieved is higher than the peak frequency fp. While different from Comparative Example 1 in these respects, the acceleration characteristic A obtained from the voltage characteristic V of this embodiment satisfies the requirement for achieving an acceleration exceeding the target acceleration At (2.5 Gal) within the target frequency band (50 Hz to 100 Hz).

[0054] The voltage characteristic V2 of Comparative Example 2 specifies a second voltage VL (e.g., 2.6V) that ensures the amplitude at the peak frequency fp does not exceed the upper limit amplitude Wmax, and drives the vehicle at this second voltage VL across all frequency bands. In other words, the voltage characteristic of Comparative Example 2 uses "no voltage control (but low voltage)" across the entire frequency band. However, while the amplitude characteristic W0 satisfies the necessary condition of not exceeding the upper limit amplitude Wmax, the acceleration characteristic A2 fails to meet the target acceleration (2.5 gal) in a portion of the target frequency band (50 Hz to 100 Hz).

[0055] (Main Effects of This Embodiment) As described above, the actuator 1 of this embodiment includes: a support body 2 and a movable body 3; a connector 9 connected to the movable body 3 and the support body 2; a magnetic drive circuit 4 that causes the movable body 3 to vibrate relative to the support body 2; and a control unit 1A that controls the drive current supplied to the magnetic drive circuit 4. The connector 9 is a viscoelastic body. The maximum amplitude of the movable body 3 that does not collide with the support body 2 is set to the upper limit amplitude Wmax, the frequency at which the acceleration or amplitude of the movable body 3 is maximum when the voltage of the drive current is constant is set to the peak frequency fp, the voltage at which the acceleration of the movable body 3 reaches or exceeds the predetermined target acceleration At in the target frequency band including the peak frequency fp and the amplitude of the movable body 3 exceeds the upper limit amplitude Wmax at the peak frequency fp is set to the first voltage VH, and when the voltage of the drive current is set to the first voltage VH, the frequency band at which the amplitude of the movable body 3 becomes or exceeds the upper limit amplitude Wmax is a mid-frequency band from a first frequency f1 lower than the peak frequency fp to a second frequency f2 higher than the peak frequency fp, the control unit 1A sets the voltage of the drive current to the first voltage VH when driving in the low frequency band below the first frequency f1 and the high frequency band above the second frequency f2, and sets the voltage of the drive current to a voltage lower than the first voltage VH and causing the amplitude of the movable body 3 to become or less than the upper limit amplitude Wmax when driving in the mid-frequency band.

[0056] According to this embodiment, the acceleration of the movable body 3 can be increased not only at frequencies near the peak frequency fp, but also over a wider frequency range. Specifically, the voltage capable of achieving the target acceleration Δt within the target frequency band is set to the first voltage VH, and a current of the first voltage VH is supplied as long as the amplitude of the movable body 3 does not exceed the upper limit amplitude Wmax, thereby achieving a higher acceleration. On the other hand, in the frequency band where the amplitude of the movable body 3 exceeds the upper limit amplitude Wmax when driven with the first voltage VH, the voltage of the drive current is set lower than the first voltage VH, thereby preventing the movable body 3 from colliding with the support body 2. Thus, an actuator 1 is provided that can achieve the target acceleration Δt within the target frequency band and prevent the movable body 3 from colliding with the support body 2.

[0057] In this embodiment, when driving at a frequency in the mid-frequency band (i.e., the frequency band in which the amplitude of movable body 3 becomes equal to or greater than the upper limit amplitude Wmax when a current of the first voltage VH is supplied), control unit 1A controls the voltage of the driving current to reduce it to a voltage at which the amplitude of movable body 3 matches the upper limit amplitude Wmax. This maximizes the acceleration of movable body 3, thereby increasing the vibration felt by the user.

[0058] In this embodiment, the peak frequency fp is the peak frequency of acceleration at which the acceleration of movable body 3 reaches its maximum value when the voltage of the drive current is set to a constant value. Alternatively, the peak frequency of amplitude at which the amplitude of movable body 3 reaches its maximum value can be determined based on the amplitude characteristics of movable body 3 when the voltage of the drive current is set to a constant value, and this peak frequency can be used as the peak frequency fp.

[0059] In this embodiment, the target frequency band is set to 50 Hz to 100 Hz. By performing voltage control as in this embodiment, the target acceleration At (for example, At = 2.5 Gal) can be obtained not only at frequencies near the peak frequency fp but also within a wide range of z from 50 Hz to 100 Hz.

[0060] In this embodiment, when driving at frequencies within the range of the first frequency f1 to the peak frequency fp, the control unit 1A reduces the voltage of the drive current as the frequency increases. When driving at the peak frequency fp, the drive current voltage is set to a voltage that causes the amplitude of the movable body 3 to coincide with the upper limit amplitude Wmax. When driving at frequencies within the range of the peak frequency fp to the first frequency f1, the control unit 1A increases the drive current voltage as the frequency increases. In this way, by adopting a voltage pattern that achieves the lowest voltage at the peak frequency fp, the acceleration of the movable body 3 can be caused to exceed the target value over a wide range. Furthermore, the amplitude of the movable body 3 can be caused to coincide with the upper limit amplitude Wmax over a wide frequency band, allowing the acceleration of the movable body 3 to be increased over a wide frequency band.

[0061] In this embodiment, the magnetic drive circuit 4 includes a coil 6 and a magnet 7 that opposes the coil 6 in a first direction Z. The magnetic drive circuit 4 causes the movable body 3 to vibrate in a second direction X, intersecting the first direction Z, relative to the support body 2. The viscoelastic element is positioned relative to the support body 2 and the movable body 3 in the first direction Z, with the first direction Z being the thickness direction. When the movable body 3 moves relative to the support body 2 in the second direction X, the viscoelastic element deforms in the shear direction. In this configuration, by adjusting the properties of the viscoelastic element, the acceleration of the movable body 3 can be increased over a wide frequency band. Therefore, by adjusting the voltage of the drive current, the amplitude of the vibration of the movable body 3 can be prevented from becoming excessively large, thereby preventing the movable body 3 from colliding with the support body 2.

[0062] In this embodiment, the viscoelastic body can be made of silicone. By adjusting the material ratio, the viscoelastic properties of the silicone (spring element + damping element) can be adjusted. Therefore, a viscoelastic body with a high damping coefficient can be selected. Explanation of symbols

[0063] 1...Actuator, 1A...Control Unit, 2...Supporting Body, 3...Movable Body, 4...Magnetic Drive Circuit, 5...Wiring Board, 6...Coil, 7...Magnet, 9...Connector, 10...First Housing Component, 10a...Hole, 11...First End Plate, 12...First Side Plate, 13...Recess, 20...Second Housing Component, 21...Second End Plate, 22...Second Side Plate, 23...Recess, 24...Recess, 30...Coil Holder, 30a, 30b...Protrusions, 31...First Coil Arrangement Hole, 32...Second Coil Arrangement Hole, 33...Plate, 34...Partitioning Section, 35, 36...Recesses, 40...Plate, 50...Spring , 51...convex portion, 52...locking portion, 55...receiving portion, 56...locking portion, 61...first coil, 62...first coil, 71, 72...first magnet, 73, 74...second magnet, 80...yoke, 81...first plate portion, 82...second plate portion, 83, 84...connecting plate portion, 85...first yoke, 86...second yoke, 91...first connecting body, 92...second connecting body, 201, 202, 203...sealing component, 301...cutout portion, 302...opening portion, 303, 304, 305...recessed portion, 601...effective edge, 602...central hole, X...second direction, Y...third direction, Z...first direction.

Claims

1. An actuator, characterized in that: have: Supporting body and movable body; a connecting body connected to the movable body and the supporting body; a magnetic drive circuit for vibrating the movable body relative to the supporting body; as well as a control unit that controls a driving current supplied to the magnetic driving circuit, The connector is a viscoelastic body, The maximum amplitude of the movable body without colliding with the supporting body is set as the upper limit amplitude, The frequency at which the acceleration or amplitude of the movable body reaches a maximum when the voltage of the driving current is set to a constant value is defined as the peak frequency. a voltage at which the acceleration of the movable body reaches or exceeds a predetermined target acceleration in a target frequency band including the peak frequency and the amplitude of the movable body exceeds the upper limit amplitude at the peak frequency, as a first voltage; When the frequency band in which the amplitude of the movable body becomes equal to or greater than the upper limit amplitude when the voltage of the drive current is the first voltage is a mid-frequency band from a first frequency lower than the peak frequency to a second frequency higher than the peak frequency, When driving in a low frequency band below the first frequency and a high frequency band above the second frequency, the control unit sets the voltage of the driving current to the first voltage. When driving in the intermediate frequency band, the control unit sets the voltage of the driving current to a voltage lower than the first voltage and at which the amplitude of the movable body becomes equal to or less than the upper limit amplitude.

2. The actuator according to claim 1, characterized in that When driving at a frequency in the intermediate frequency band, the control unit sets the voltage of the driving current to a voltage such that the amplitude of the movable body matches the upper limit amplitude.

3. The actuator according to claim 1, wherein: The target frequency band is greater than or equal to 50 Hz and less than or equal to 100 Hz.

4. The actuator according to claim 1, wherein: The peak frequency is an acceleration peak frequency at which the acceleration of the movable body reaches a maximum when the voltage of the drive current is set to a constant value.

5. The actuator according to claim 1, wherein: When driving at a frequency in the low frequency band, the control unit reduces the voltage of the driving current as the frequency increases. When driving at the peak frequency, the control unit sets the voltage of the driving current to a voltage such that the amplitude of the movable body matches the upper limit amplitude. When driving at a frequency in the high frequency band, the control section increases the voltage of the driving current as the frequency increases.

6. The actuator according to claim 1, wherein: The magnetic drive circuit includes a coil and a magnet facing the coil in a first direction, and vibrates the movable body relative to the support body in a second direction intersecting the first direction. The viscoelastic body is arranged with the first direction as its thickness direction at a position where the support body and the movable body are opposite to each other in the first direction. When the movable body moves relative to the support body in the second direction, the viscoelastic body deforms in a shear direction.

7. The actuator according to claim 1, wherein: The viscoelastic body is silicone.

Images