JPH04355653A - Vibration actuator for portable apparatus - Google Patents

Abstract

PURPOSE:To provide a vibration actuator for a portable apparatus whose current consumption is small, thickness is thin and construction and drive circuit are simple. CONSTITUTION:A printed wiring board 25 on which a coil 21 composed of a driving coil 22 and a position detecting coil 23 which are wound concentrically are formed with spring members 26 which support the printed wiring board 25 by its one end as a cantilever so as to facilitate reciprocal movement of the printed wiring board 25 in the same plane as itself are provided. Further, a case which serves also as a back yoke on which a permanent magnet facing the one surface of the coil 21 with a gap is formed and a stator board on which a stator yoke facing the other surface of the coil 21 with a gap is formed are provided. The spring members 26 are also used as lead wires and are so selected as to produce resonance vibration. The coil 21 may be formed by printing on the printed wiring board 25.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention is an information transmission device such as a card-type pager, a wristwatch, a mobile phone, or a signal receiver for the blind, by transmitting vibrations generated from a vibration actuator to the human body. The present invention relates to a vibration actuator for a mobile device that transmits information on the type of information to a person carrying the mobile device. Hereinafter, in this specification, a device that transmits certain types of information by transmitting vibrations to the human body will be simply referred to as an "information transmission device."

0002

[Prior Art] An information transmission device using a vibration motor is
Because it is possible to transmit certain types of information using only vibration without disturbing those around you, in recent years it has come to be used in pagers, wristwatches, mobile phones, and signal receivers for the blind. . In conventional vibration motors, a half-moon-shaped weight, for example, is attached to the tip of a motor shaft of a cylindrical motor, and the motor is rotated at high speed to obtain vibration. Since it is difficult to make such a cylindrical motor thin as a card-type portable information transmission device, a flat vibration motor has been developed. For example, FIG. 5 is a schematic cross-sectional view of a flat brushless motor used in a conventional information transmission device. In FIG. 5, a printed wiring board 51' on which a plurality of stator coils 52, for example, 3-phase 6 coils are formed, is mounted on a stator yoke substrate 51, and a bearing 53 is mounted at the center of the printed wiring board 51'. There is. In addition, the stator yoke substrate 51
also serves as a motor case made of a magnetic material, and the motor case is omitted in the upper part of the figure. A shaft 54 is rotatably inserted into the bearing 53. A plate-shaped rotor magnet 57 is fixed to the shaft 54 via a rotor bush 55. The rotor magnet 57 is magnetized to have a desired number of magnetic poles, for example eight poles, and faces the stator coil 52 . A flat type brushless motor having such a configuration detects the position of the rotor magnet 57 and moves the stator coil 5
A control circuit (not shown) that sequentially generates a rotating magnetic field at the rotor magnet 57 causes the rotor magnet 57 to generate rotational force. When a rotary vibration device is obtained using a flat brushless motor as described above, an eccentric weight having a high specific gravity such as tungsten is attached to the rotating shaft of the motor to generate vibrations. Furthermore, if a protruding magnetic attraction section (not shown) is provided on a part of the stator yoke substrate 51 of such a flat type brushless motor, this magnetic attraction section can take advantage of the change in the attraction force of the rotor magnet 57. to give vibration to the rotation of the rotor.

FIG. 6 shows a conventional example of a vibration source used in an electric shaver. In FIG. 6, a pair of permanent magnets 62 and 62' are fixed to the inner surface of a yoke 61 having a U-shaped cross section to constitute a movable element 63. The stator 64 is
A pair of coils 65 and 65' are wound in opposite directions and approximately in a planar shape. The coils 65, 65' are arranged so as to generate electromagnetic force by the magnetic field of the pair of permanent magnets 62, 62'. a pair of springs 66;
66' is attached at one end to both ends of the movable element 63 so that it can easily vibrate, and at the other end is fixed to a substrate (not shown) together with the stator 64 by fixing screws 69, 69'. The position detector 67 is arranged in a hollow space in the center of the coils 65, 65', and is fixed integrally with the coils 65, 65'. Furthermore, when the position detector 67 is pressurized by the slider 68 provided on the movable element 63, the resistance value changes due to this pressurization, and the position of the coils 65, 65' is detected.

FIG. 7 shows a drive circuit for the vibration source shown in FIG. When the position detector 67 and the slider 68 are in the position shown in FIG. 6, the position detector 67 is pressurized by the slider 68,
Shows low resistance value. When the mover 63 moves in the direction indicated by the dotted line or the solid arrow, the position detector 67 moves the slider 68
It is no longer pressurized and exhibits a high resistance value. In the state shown in FIG. 6, the position detector 67 is pressurized by the slider 68 and has a low resistance value. As a result, the base of the transistor 71 goes to L level, and the input to the T terminal and the output to the Q terminal of flip-flop 74 go to H level. Further, since the output of the Q' terminal of the flip-flop 74 becomes L level, the output of the AND circuit 75 becomes H level, turning on the transistor 72. Therefore, current flows through the coil 65. On the other hand, flip
Since the output of the Q' terminal of the flop 74 is at L level, the transistor 73 is turned off and no current flows through the coil 65'. An electromagnetic force acts on the movable element 63 due to the current flowing through the coil 65 and the magnetic field of the permanent magnets 62, 62', and the movable element 63 moves in the direction of the dotted arrow in FIG. This force causes the slider 68 to separate from the position detector 67 and no longer pressurize the position detector 67. As a result, the resistance value of the position detector 67 becomes high, the base potential of the transistor 71 becomes high, the transistor 71 is turned on, and the input of the T terminal of the flip-flop 74 and the AND circuit 75 are turned on.
The input is set to L level. Therefore, transistor 7
No current flows through 2. At this time, flip-flop 7
The output of the Q' terminal of 4 becomes H level, and the AND circuit 7
6, transistor 73 is turned on, and current flows through coil 65'. Since the coils 65 and 65' are wound in opposite directions, when current flows through the coil 65', the current flowing through the coil 65' and the permanent magnet 62 cause the mover 6 to
The electromagnetic force acting on 3 is in the opposite direction to the above. therefore,
As the slider 68 moves, the resistance of the position detector 67 changes, and the transistors 72 and 73 connected to the coils 65 and 65' turn on and off alternately. The flowing current is switched to continue the reciprocating motion of the movable element 63.

[0005]

[Problems to be Solved by the Invention] Vibration sources using cylindrical motors or flat motors rotate a weight with an unbalanced mass attached to the shaft at high speed, so the battery capacity to drive the motor is limited. The vibration source was large and could not be made small and thin enough to be used as a vibration source for mobile devices. Furthermore, the above-mentioned motor has a short lifespan because rotating parts such as the shaft are worn out due to vibrational rotation, and the weight is made of expensive tungsten or the like, making it an expensive source of vibration. Also, if the above vibration motor has a brush or commutator,
These have caused problems such as large sliding noises, impact noises to bearings, and mechanical noises. Furthermore, the flat motor that solved some of the above problems is coreless, so
Torque generation efficiency is poor and current consumption is high. Further, in the case of a vibration source as shown in FIG. 6, it is good for obtaining large vibrations like an electric shaver. However, as a vibration source that simply transmits information to a person carrying an information transmission device, it consumes a large amount of current, and it has been impossible to manufacture it in a small size. Further, the vibration source requires a pair of coils, a permanent magnet, and a spring, and a drive circuit also requires a pair of transistors and an AND circuit. Therefore, it has not been possible to obtain an inexpensive vibration source with a simple structure. In the conventional rotary vibrating section or reciprocating vibrating section, there is an air gap between the coil and the permanent magnet, and there is also an air gap between the vibrating section equipped with the permanent magnet and the case that covers it. . Therefore, there is a limit to how thin the vibration source can be made.

The present invention is intended to solve the above-mentioned problems. For example, a vibration actuator for a portable device that requires only the current consumption of a lithium battery (several 10 mA) and is thin enough to match the thickness (2 mm) of the lithium battery. The purpose is to provide Another object of the present invention is to provide a vibration actuator for portable equipment that has a simple structure and drive circuit.

[0007]

[Means for Solving the Problems] In order to achieve the above object, a vibration actuator for a portable device according to the present invention is provided with a vibration actuator for a portable device having a coil including a drive coil and a position detection coil wound concentrically. A wiring board, a spring member that supports one end of the printed wiring board as a cantilever so that the printed wiring board can reciprocate within the same plane, and a permanent magnet arranged to face one side of the coil with a gap therebetween. The stator substrate is composed of a case that also serves as a back yoke, and a stator substrate on which a stator yoke is formed so as to face the other side of the coil with a gap therebetween.

[0008] The spring member in the vibration actuator for portable equipment of the present invention is configured to also serve as a lead wire for electrically connecting the coil provided on the printed wiring board and the terminal provided on the spring support portion. .

The coil in the vibration actuator for portable equipment of the present invention is configured to be printed on a printed wiring board.

The drive circuit in the vibration actuator for portable equipment of the present invention includes a comparator that compares the voltage applied to the drive coil and the voltage generated in the position detection coil, and a voltage applied to the drive coil based on the output of the comparator. It consists of a switch means for turning on and off.

The period of the reciprocating motion of the printed wiring board in the vibration actuator for portable equipment of the present invention is determined by the mass of the printed wiring board and the spring constant of the spring member.

0012

[Operation] The drive coil and position detection coil are
For example, it is formed by providing or printing concentrically wound air-core coils on a printed wiring board. This printed wiring board is supported at one end by a cantilever made of a spring member. Further, the voltage applied to the coil can be applied using the spring member as a lead wire. That is, one of the spring members is connected to a coil on the printed wiring board, and the other is connected to a terminal provided on the spring support. After storing the printed wiring board, spring member, etc. in a case that also serves as a back yoke and has a permanent magnet formed thereon, the opening of the case is covered with a stator board that has a stator yoke formed therein. . At this time, an air gap exists between the coil and the permanent magnet and between the coil and the stator yoke. In such a state, when a current flows through the drive coil, the current flowing through the coil and the permanent magnet generate an electromagnetic force in the coil, and the printed wiring board on which the coil is installed uses the other spring member as a fulcrum. Move within that same plane. Then, after the current stops flowing through the drive coil, the printed wiring board is restored to its original position by the force of the spring member. That is, by turning ON/OFF the current flowing through the drive coil, the printed wiring board continuously repeats reciprocating motion within the same plane. The period of this reciprocating motion is determined by the resonance state caused by the mass of the printed wiring board, the coils attached to the printed wiring board, circuit components of the drive circuit, etc., and the spring constant of the spring member. The spring constant can be changed depending on the shape of the spring member, for example, whether the cross section is round or square, or depending on the material. When current is applied to the drive coil, the printed wiring board moves as described above, the electromotive force generated in the position detection coil decreases, and this voltage is input to the comparator. The voltage applied to the drive coil is fed back to the other input of the comparator. The output of the comparator at this time acts to turn off the switch provided between the drive coil and the power source. When current no longer flows through the drive coil, the printed wiring board returns to its original position due to the restoring force of the spring member, returning to its initial state. Repeat this to perform a reciprocating motion. The printed wiring board is subjected to a force that moves it in the same plane while current is flowing through the coil as described above. When current no longer flows through the coil, it returns to its original position only by the force of the spring member, so current consumption is small and the control circuit is simple. In the structure of a vibration actuator, the stator yoke and back yoke also serve as the case, so the thickness can be reduced by the air gap that conventionally existed between the case and the vibration actuator. As described above, the vibration actuator for a portable device of the present invention has a simple structure, consumes enough current to use a lithium battery, and can have approximately the same thickness as a lithium battery. Furthermore, in order to efficiently reciprocate the printed wiring board, the supporting spring member should be appropriately selected in terms of the mass of the printed wiring board and the spring member, as well as the material and cross-sectional area of the spring member. I am trying to make it resonate by.

[0013]

[Embodiment] An embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a perspective view of an embodiment of a case that also serves as a back yoke in the present invention. FIG. 2 shows an embodiment of a printed wiring board on which a coil according to the present invention is mounted. FIG. 3 shows an embodiment of the stator substrate according to the present invention. FIG. 4 is a diagram illustrating an embodiment of a vibration actuator drive circuit according to the present invention. In FIG. 1, a permanent magnet 11 is, for example, a neodymium-iron-boron permanent magnet, and is formed at a position corresponding to a coil 21, which will be described later, on the inner surface of a case 12 made of, for example, iron. Further, since the case 12 is made of iron, it can also serve as a back yoke for the drive coil 22, which will be described later. In FIG. 2, the coil 21 is composed of a drive coil 22 and a position detection coil 23, which are wound concentrically and air-core. The drive coil 22 and the position detection coil 23 can also be arranged on the same plane or overlapping each other. Further, the coil 21 wound in this manner is embedded in, for example, a groove formed on the printed wiring board 25. Further, the coil 21 is connected to the printed wiring board 2
It can also be formed by printing on 5. The coil 21 is
If they are formed by printing, they can be connected to the drive circuit 41 formed on the printed wiring board 25 by a wiring pattern (not shown) on the printed wiring board 25, without having to be connected to the drive circuit 41 by a lead wire. A spring member 26 made of, for example, stainless steel or phosphor bronze is provided at one end of the printed wiring board 25.
One side of the spring member 26 is attached, and the other side of the spring member 26 is fixed to a spring support part 27. Therefore, the printed wiring board 25 supports the printed wiring board 25 with the spring support part 27 as a fulcrum.
The movable element 20 is movable within the same plane as the movable element 5. Also,
The spring member 26 can be used not only for supporting the printed wiring board 25 but also for electrical connection. In this case, the spring member 2
As shown in FIG. 2, 6 is a set of two wires, one of which is connected to terminals 28 and 29 formed on the spring support 27, and the other connected to the coil 21 via a wiring pattern not shown. has been done. Further, when electrical connection is made, it goes without saying that the spring member 26 is made of a good electrical conductor. In FIG. 3, stator board 31
corresponds to a lid that closes the opening side of the case 12 after the printed wiring board 25, the spring member 26, etc. are housed in the case 12. A stator yoke 32 made of, for example, iron is formed on the stator substrate 31 at a position corresponding to the coil 21 . Furthermore, power supply terminals 33 and 34 are provided at both ends of the stator board 31, for example. Connection terminal 37 on stator board 31,
38 is provided at a position corresponding to the terminals 28 and 29 connected to the spring member 26, and is electrically connected to the power supply terminals 33 and 34 by wiring patterns 35 and 36. When the coil 21, drive circuit 24, spring member 26, spring support section 27, etc. shown in FIG. A slight air gap exists between the permanent magnets 11 and the stator yoke 32. Therefore, the printed wiring board 25 is
2, it can move in the direction of the white arrow shown in FIG. 2 using the spring support part 27 as a fulcrum.

Next, the vibration actuator drive circuit 41 will be explained with reference to FIG. In FIG. 4, the drive circuit 41 includes a drive coil 22 that vibrates the movable element 20,
A position detection coil 23 that detects the position of the mover 20; a transistor 43 that connects a power source 42, such as a lithium battery, to the drive coil 22; For example, a comparator 4 consisting of a differential amplifier inputs the voltage of
4, and the output of the comparator 44 is connected to the transistor 43.
, and a power switch 45 that supplies current to the drive coil 22. When the power source 42 is turned on by the power switch 45, current flows through the drive coil 22. The mover 20 is caused by the current flowing through the drive coil 22 and the magnetic field generated by the permanent magnet 11.
An electromagnetic force acts on the movable element 20, and the movable element 20 moves within the same plane using the spring support part 27 as a fulcrum. When the movable element 20 moves, the relative positions of the coil 21 formed on the movable element 20 and the permanent magnet 11 shift. Therefore, the electromotive force generated in the position detection coil 23 decreases, and this voltage is input to one terminal of the comparator 44. The voltage input to the other terminal of the comparator 44 is the voltage applied to the drive coil 22 that is fed back by the feedback resistor Rf. The output voltage of the comparator 44 at this time acts so that the transistor 43 located between the drive coil 22 and the power supply 42 is turned off. As a result, when current no longer flows through the drive coil 22, the coil 21 returns to its original position due to the restoring force of the spring member 26, returning to its initial state. This is repeated to perform reciprocating motion.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. and,
Various design changes can be made without departing from the scope of the invention as set forth in the claims. For example, the spring member may have any shape other than that shown in FIG. 2 as long as the cross section can be deformed and the spring member can move in the same plane as the coil. Furthermore, any material other than those described in the embodiments can be used for the spring member and the permanent magnet. Similarly, the drive circuit is not limited to the embodiment, and can be replaced with circuit components having equivalent functions.

[0016]

According to the present invention, since there is no mechanical friction part and the mechanical loss is only caused by the spring member, it is possible to provide a vibration actuator for portable equipment with a simple structure, low noise, and long life. In addition, current is applied only when the mover moves in one direction during reciprocating motion, and when restoring, the force of the spring member that also serves as a lead wire is used, so current consumption is low and the mover and drive circuit can be easily assembled. Make it. Furthermore, when the coil is wound around an air core in the same plane, the thickness of the vibration actuator for mobile devices can be reduced, and since there is no iron loss and no magnetic attraction that restrains the permanent magnet, the coil can be used as a spring member. The spring pressure can be reduced. According to the present invention, it is possible to print a coil on a printed wiring board or use the wiring pattern of the printed wiring board to connect a coil, a drive circuit, a spring member, or connect a connecting terminal to a power supply terminal, etc. , it is easy to manufacture vibration actuators for mobile devices.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of a case that also serves as a back yoke in the present invention.

FIG. 2 shows an embodiment of a printed wiring board on which a coil according to the present invention is mounted.

FIG. 3 shows an embodiment of a stator substrate in the present invention.

FIG. 4 is a diagram illustrating an embodiment of a vibration actuator drive circuit according to the present invention.

FIG. 5 is a schematic cross-sectional view of a flat brushless motor used in a conventional information transmission device.

FIG. 6 shows a conventional example of a vibration source used in an electric shaver.

FIG. 7 is a drive circuit for the vibration source shown in FIG. 6.

[Explanation of symbols]

11 Permanent magnet 12 Case (back yoke) 20 Mover 21 Coil 22 Drive coil 23 Position detection coil 24 Drive circuit 25 Printed wiring board 26 Spring member 27 Spring support part 28, 29 terminal 31 Stator board 32 Stator yoke 33, 34 Power supply terminal 35, 36 Wiring pattern 37, 38 Connection terminal 41 Drive circuit 42 Power supply 43 Transistor 44 Comparator 45 Power switch

Claims (5)

[Claims] 1. A printed wiring board 25 provided with a coil 21 composed of a drive coil 22 and a position detection coil 23 wound concentrically, and the printed wiring board 25 capable of reciprocating within the same plane. A spring member 26 that supports one end as a cantilever beam, a case 12 that also serves as a back yoke and a permanent magnet 11 that is arranged to face one side of the coil 21 with a gap, and a case 12 that also serves as a back yoke; A vibration actuator for a portable device, comprising: a stator substrate 31 on which a stator yoke 32 is formed so as to face each other with a gap between the surfaces thereof. 2. The spring member 26 also serves as a lead wire that electrically connects the coil 21 provided on the printed wiring board 25 and the terminals 28 and 29 provided on the spring support portion 27. The vibration actuator for portable equipment according to claim 1. 3. The vibration actuator for a portable device according to claim 1, wherein the coil 21 is printed on a printed wiring board 25. 4. A comparator 44 for comparing the voltage applied to the drive coil 22 and the voltage generated in the position detection coil 23, and a switch means for turning on/off the voltage applied to the drive coil 22 based on the output of the comparator 44. 4. The vibration actuator for a portable device according to claim 1, further comprising a drive circuit (41) for a printed wiring board (25) consisting of: (43). 5. The vibration actuator for a portable device according to claim 1, wherein the period of the reciprocating motion of the printed wiring board 25 is determined by the mass of the printed wiring board 25 and the spring constant of the spring member 26.