JP2017147678A - Electromechanical converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromechanical converter suitable for cost reduction and compaction by simple processing, while positioning an armature reliably.SOLUTION: An electromechanical converter includes a structure where two pairs of magnet, yokes 10a, 10b leading the magnetic flux of this magnet, and a coil 11 supplied with an electric signal are arranged integrally, a flat plate shaped armature 12 penetrating the internal space of the structure, and where two areas leading magnetic fluxes in opposite directions are arranged oppositely in the X direction, and constituting the structure and a magnetic circuit via two areas, and displacing in a displacement direction (Z direction) based on the magnetic force of the magnetic circuit, and a pair of elastic members 13a, 13b arranged on the opposite sides in the Z direction for this armature, and imparting resilience according to relative displacement for the structure of the armature to the armature. At each position facing two areas, out of the opposite faces of the armature, two pairs of flat plate shaped pole pieces are attached oppositely to the magnet.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electromechanical converter that converts an electric signal into mechanical vibration, and more particularly to an electromechanical converter that includes a drive unit including an armature, a yoke, a coil, a magnet, and the like.

  An electromechanical transducer used for a hearing aid or the like includes a drive unit including an armature, a yoke, a coil, a magnet, and the like, drives the armature in accordance with an electric signal supplied to the coil, and between the armature and other members. It is configured to convert relative vibration to mechanical vibration. A so-called balanced armature type electromagnetic transducer has a magnetic circuit using an armature, and when the armature is displaced, the restoring force due to the elasticity of the armature itself is larger than the magnetic force of the magnet generated by the displacement. Configured. For example, Patent Document 1 discloses a flat armature as an electromechanical transducer that can satisfy both magnetic and mechanical requirements for armature design, and a restoring force applied to the armature. A structure has been proposed in which two elastic mechanisms (spring members) are provided, and an engaging portion of each elastic mechanism is engaged with an outer portion of the armature. The electromechanical transducer having such a structure can reduce the design restrictions of the armature, improve the impact resistance, and reduce the size and increase the output.

Japanese Patent Laid-Open No. 2015-154402

  Since the electromechanical transducer disclosed in Patent Document 1 has a structure in which the outer portion of the armature is engaged with the engaging portion of the elastic mechanism, a structure including a magnet, a yoke, a coil, and the like when no current flows through the coil The armature can be positioned at a predetermined position in the internal space of the part. However, when such a structure is employed, high-precision and fine processing is required for engaging the armature and the elastic mechanism with each other. Therefore, it is difficult to reduce the cost of the electromechanical converter, and it is not suitable for downsizing of components.

  The present invention has been made to solve these problems. An electromechanical conversion suitable for cost reduction and miniaturization by simple processing while reliably positioning an armature to which a restoring force is applied by an elastic member. The purpose is to provide a vessel.

  In order to solve the above-described problems, the present invention provides an electromechanical transducer that converts an electrical signal into mechanical vibration, and includes at least two pairs of magnets (14), a yoke (10) that guides magnetic flux by the magnets, and the electric The flat plate is composed of a structure part in which a coil (11) to which a signal is supplied is integrally arranged and a flat plate member penetrating through the internal space of the structure part, and the magnetic fluxes directed in opposite directions are guided to the flat plate. Is disposed opposite to the first direction (X) of the member, forms the magnetic circuit with the structure portion via the two regions, and is displaced in the displacement direction (Z) based on the magnetic force of the magnetic circuit. And a pair of elastic portions disposed on both sides in the displacement direction with respect to the armature and imparting a restoring force to the armature according to relative displacement of the armature with respect to the structure portion (13) and two pairs of plate-shaped pole pieces (15) respectively facing the two pairs of magnets at positions facing the two regions on both surfaces of the armature. It is characterized by being attached.

  According to the electromechanical transducer of the present invention, the armature penetrating the internal space of the structure portion concentrates the magnetic flux on the portion where the pole piece and the magnet attached to the two regions on both surfaces face each other. The armature is relatively displaced by a magnetic force when an electric current is passed through the coil, and a restoring force corresponding to the displacement of the armature is applied through a pair of elastic members in contact with the armature. Therefore, while using an armature with a high degree of design freedom, high-precision and fine processing for engaging the armature with a pair of elastic members is unnecessary, and electromechanical conversion suitable for cost reduction and miniaturization Can be realized.

  The pole piece of the present invention can be formed in the same shape as seen from the direction of displacement with the magnet facing through the two regions. Thereby, the armature can be stably positioned at a position where the pole piece and the magnet overlap each other when viewed from the displacement direction. In this case, a pole piece side magnet may be provided on the surface of the pole piece, and the pole piece side magnet may be formed in the same shape as the magnet when viewed from the displacement direction.

  As each of the pair of elastic members of the present invention, a pair of contact portions that contact both sides of the armature in the first direction to give a restoring force, and a pair of fixing portions fixed to the end of the yoke, A spring member having the following can be used. Thereby, a restoring force can be reliably applied to the armature through the pair of contact portions of the spring member without engaging the armature with the pair of elastic members. In this case, it is desirable that each of the pair of spring members has an opening that surrounds the yoke, and a part of the yoke protrudes from the opening in the displacement direction. With such a structure, it is possible to avoid misalignment due to external force applied to the spring member when handling the electromechanical transducer. Further, the pair of fixing portions can be respectively fixed to the protruding portions located on both sides of the first direction and the second direction orthogonal to the displacement direction across the opening in the yoke.

  According to the present invention, since the pole piece is attached to the position of the flat armature facing the magnet, the armature is reliably positioned without engaging the armature with a pair of elastic members for applying a restoring force to the armature. Thus, high-precision and fine processing is not required, and the cost and size of the electromechanical converter can be reduced.

It is a top view when the drive part in the electromechanical converter of this embodiment is seen from one side of a Z direction. It is a front view when the drive part in the electromechanical converter of FIG. 1 is seen from one side of the Y direction. It is a side view when the drive part in the electromechanical converter of FIG. 1 is seen from one side of the X direction. It is a disassembled perspective view of the magnetic circuit part in the electromechanical converter of this embodiment. It is a perspective view which shows the whole structure of a spring member. It is a figure which shows the partial cross-section of only a yoke, a coil, an armature, four pole pieces, and four magnets among the components of the electromechanical converter of this embodiment. It is the figure which represented typically the line of magnetic force which acts between a magnet and a pole piece. It is a figure which shows the modification of the cross-section of FIG. It is a figure which shows the structure of the state which removed the drive part in the electromechanical converter of the structure shown in FIG. 2, and the housing which accommodates the whole. It is a figure which shows the structure of the state in which the housing which accommodates the whole electromechanical transducer of this embodiment was integrated.

  A preferred embodiment of the present invention will be described with reference to the drawings. However, the embodiment described below is an example to which the present invention is applied, and the present invention is not limited by the contents of the present embodiment. Hereinafter, an embodiment in which the present invention is applied to an electromechanical transducer that converts an electrical signal into mechanical vibration will be described.

  Hereinafter, the basic structure of the electromechanical transducer of this embodiment will be described with reference to FIGS. 1-3, the X direction (the first direction of the present invention), the Y direction (the second direction of the present invention), and the Z direction (the displacement direction of the present invention) orthogonal to each other are indicated by arrows. Yes. The electromechanical transducer of this embodiment does not have the direction of up, down, left, and right, but in the following, for convenience of explanation, it corresponds to the direction (X, Y, Z) in each drawing (paper surface). In some cases, the top, bottom, left, and right directions are described.

  FIG. 1 is a top view of the electromechanical transducer of this embodiment as viewed from one side in the Z direction, and FIG. 2 is a front view of the electromechanical transducer in FIG. 1 as viewed from one side in the Y direction. FIG. 3 is a side view of the electromechanical transducer of FIG. 1 when viewed from one side in the X direction. FIG. 4 is an exploded perspective view of a later-described magnetic circuit unit in the electromechanical transducer of the present embodiment.

  As shown in FIGS. 1-4, the drive part of the electromechanical converter of this embodiment is a pair of yokes 10 (10a, 10b), a coil 11, an armature 12, and a pair of spring members. 13 (13a, 13b), two pairs (four pieces) of magnets 14, and two pairs (four pieces) of pole pieces (pole pieces) 15. Among this drive part, a pair of yoke 10, coil 11, and four magnets 14 function as the structure part of this invention arrange | positioned integrally. That is, the armature 12 that penetrates the internal space of the structure portion is arranged so as to be movable with respect to the structure portion via a pair of spring members 13. Although not shown in FIGS. 1 to 4, the entire electromechanical transducer of this embodiment is integrally accommodated in a housing 20 (FIGS. 9 and 10) described later.

  The pair of yokes 10 are integrally fixed by welding, for example, in a state where the upper yoke 10a and the lower yoke 10b are opposed to each other in the Z direction. As shown in FIG. 4, the air-core coil 11 is disposed so as to be sandwiched between the centers of the inner surfaces of the upper and lower yokes 10a and 10b. The coil 11 is formed with through holes that are open at both ends in the X direction, and a pair of electrodes 11a (see FIGS. 1 and 2) are provided at both ends in the Y direction so that the coil 11 is electrically connected. Yes. The coil 11 is fixed to the inner surfaces of the yokes 10a and 10b with an adhesive. As a material of the yokes 10a and 10b, for example, a soft magnetic material such as 45% Ni permalloy can be used.

  Four plate-like magnets 14 are symmetrically arranged at both ends in the X direction on the inner surface side of the yokes 10a and 10b. In other words, a pair of magnets 14 facing up and down at one end in the X direction of the yokes 10a and 10b and a pair of magnets 14 facing up and down at the other end in the X direction of the yokes 10a and 10b are both predetermined up and down. Are adhered and fixed to the inner surfaces of the yokes 10a and 10b, respectively.

  The armature 12 is a flat plate-like member elongated in the X direction. The space between the pair of magnets 14 at one end in the X direction, the through hole of the coil 11, and the pair of magnets 14 at the other end in the X direction. It is arranged so as to penetrate the space between each. As shown in FIG. 4, four pole pieces 15 are attached to the upper and lower surfaces of the armature 12 at positions facing the four magnets 14. The armature 12 forms a magnetic circuit together with the yokes 10a and 10b, the four magnets 14, the four pole pieces 15, and the coil 11. Each pole piece 15 has the same shape as each magnet 14 as viewed from the Z direction. As the material of the armature 12 and the four pole pieces 15, for example, a soft magnetic material such as 45% Ni permalloy can be used as in the yokes 10a and 10b.

  In a state where the armature 12 is inserted into the through hole of the coil 11, parallel gaps are formed between the four magnets 14 and the four pole pieces 15, and each gap is an air gap 16 (FIG. 6). Configure. Each air gap 16 is an appropriate gap that does not contact the coil 11 and the magnet 14 when the armature 12 is displaced in the Z direction within the range of its normal operation.

  The pair of spring members 13 (the pair of elastic members of the present invention) is a plate spring formed by bending a plate-like member having an opening, and one spring member 13a is disposed above the armature 12. At the same time, the other spring member 13 b is disposed below the armature 12. Here, FIG. 5 is a perspective view showing the entire structure of one spring member 13 (13a or 13b). Since the upper and lower spring members 13a and 13b have a symmetric structure in the Z direction across the armature 12, FIG.

  In FIG. 5, the spring member 13 has a substantially constant width W and thickness T, and is formed by a plate-like member surrounding the central rectangular opening A. The pair of fixing portions P1 of the spring member 13 are fixed to the protruding portions on both sides protruding in the Y direction at the center of each yoke 10, for example, by laser welding. Further, the pair of contact portions P2 of the spring member 13 are portions that come into contact with both end portions of the armature 12 in the X direction and are pressed from above and below. Therefore, the spring member 13 has a shape that bends in the Z direction toward the armature 12 from the position of the pair of fixing portions P1 to the position of the pair of contact portions P2. The role of the pair of spring members 13 is to give the armature 12 a restoring force proportional to the magnitude of the displacement when the armature 12 is displaced relative to the structure portion in the magnetic circuit. The spring member 13 of the present embodiment only contacts the armature 12 at the pair of contact portions P2, and a structure for engaging the spring member 13 and the armature 12 with each other is not provided.

  In addition, various designs are possible for the dimensional parameters and the detailed structure of the spring member 13. For example, with respect to the width W, thickness T, length in the X and Y directions, and the size of the opening A of the spring member 13, the pair of fixed portions P1 and the pair of contact portions P2 of the spring member 13 function. As long as the restoring force exerted and applied to the armature 12 is obtained, various dimensional shapes can be adopted. In this case, it is necessary to design these dimensional parameters so as to obtain a spring constant corresponding to the restoring force to be applied to the armature 12. Further, by providing the opening A of the spring member 13, when handling the electromechanical converter of this embodiment, the upper and lower surfaces of the yoke 10 in the opening A of the spring member 13 can be used. It is possible to avoid misalignment or the like due to external force applied to the. In addition, as a material of the spring member 13, a stainless steel material (SUS301, SUS304) etc. can be used, for example.

  Here, although not shown, the spring member 13 is fixed to the yoke 10 while being slightly pressed in the Z direction. That is, as shown in FIG. 2, the armature 12 is always sandwiched from the Z direction by the pair of spring members 13. The balance position of the armature 12 in this state is equidistant from the facing surface in the Z direction when viewed from the two magnets 14 facing in the Z direction via the armature 12 and the two pole pieces 15. Is desirable.

  Next, in relation to the basic operation of the electromechanical transducer of this embodiment, the structure and operation of a portion where the four pole pieces 15 and the four magnets 14 attached to the armature 12 face each other will be described. FIG. 6 pays attention to the yoke 10, the coil 11, the armature 12, the four pole pieces 15, and the four magnets 14 among the components of the electromechanical transducer of the present embodiment. FIG. 6A is an XZ cross-sectional view when viewed from the same direction as FIG. 2, and FIG. 6B is a YZ cross-section when viewed from the same direction as FIG. FIG.

  As shown in FIG. 6A, two pole pieces 15 are provided at two positions in the X direction of the armature 12 so that the armature 12 is sandwiched from the Z direction at each position (four pieces in total). Be placed. Each pole piece 15 faces the magnet 14 on the opposite side of the armature 12 in the Z direction. Here, the length Xa in the X direction of each of the pole piece 15 and the magnet 14 has the same dimension. The aforementioned air gap 16 is formed between each pole piece 15 and the magnet 14. Further, as shown in FIG. 6B, the length in the Y direction of two pole pieces 15 sandwiching the armature 12 in the Z direction, and two magnets 14 sandwiching the two pole pieces 15 in the Z direction. The length in the Y direction is the same as the length Ya of the armature 12 in the Y direction. The same applies to the other two pole pieces 15 and the two magnets 14. In other words, the four pole pieces 15 and the four magnets 14 are formed with a common length Xa in the X direction and a common length Ya in the Y direction, and each air gap 16 is inevitably also in the XY plane. The space has a common length Xa, Ya.

  Here, regarding the Z direction, the thickness Ta of the pole piece 15, the thickness Tb of the magnet 14, and the thickness G of the air gap 16 are all different dimensions. Among these, the thickness Ta of the pole piece 15 is set larger than the thickness Tb of the magnet 14 and the thickness G of the air gap 16. The thickness Ta of the pole piece 15, the thickness Tb of the magnet 14, and the thickness G of the air gap 16 are set so as to satisfy desired conditions, and are not particularly limited.

  In FIG. 6, when an electric current is passed through the coil 11, a magnetic flux is generated in the armature 12, and the armature 12 is displaced in the Z direction with respect to the structure portion. In this case, in FIG. 6A, the left magnet 14 and the right magnet 14 are magnetized in opposite directions, and magnetic fluxes in opposite directions are guided to the regions overlapping each magnet 14 in the Z direction 2. It corresponds to one area. Such a magnetic circuit is the same as the structure of the conventional patent document 1, for example. However, since the structure of Patent Document 1 is not provided with a member corresponding to the pole piece 15, a structure in which the outer portion of the armature is engaged with the engaging portion of the spring member is adopted. Positioning is performed. On the other hand, in this embodiment, the armature 12 and the spring member 13 are brought into contact with each other by utilizing the action described later by arranging a pole piece 15 having the same dimensions as the magnet 14 as a positioning means. They are only in contact at P2 and not engaged with each other.

  Here, FIG. 7 schematically shows lines of magnetic force M acting between the magnet 14 and the pole piece 15. The magnetic force lines M shown in FIG. 7 are based on Maxwell's stress and act to reduce the magnetic field energy generated between the magnet 14 and the pole piece 15 in the direction of the magnetic force lines M so that the energy becomes minimum. Therefore, for example, when the pole piece 15 tries to move in the direction of any thick arrow in the X direction from the position where the magnet 14 and the pole piece 15 overlap with each other in plan view, the magnetic lines of force M will be stretched. The armature 12 is positioned by the force acting on it. The same applies to the movement in the Y direction.

  FIG. 8 shows a modification of the cross-sectional structure of FIG. As shown in FIG. 8, a structure may be employed in which a pole piece side magnet 17 is further provided on the surface of the pole piece 15 so as to face the magnet 14. By adopting the modification of FIG. 8, the magnetic lines of force concentrate in the air gap 16 as compared with the pole piece 15 made of soft magnetic material, so that the effect of positioning the armature 12 due to Maxwell stress becomes significant.

  Next, the housing 20 that accommodates the entire electromechanical converter of this embodiment will be described with reference to FIGS. 9 and 10. In the electromechanical transducer according to the present embodiment, the portion of the armature 12 including each pole piece 15 other than the yoke 10, the coil 11, and the magnet 14 (structure portion of the present invention) is connected to the coil 11. Relative vibration is generated between the armature 12 and the armature 12 by the driving force corresponding to the current flowing when the electric signal is applied. Therefore, by fixing both ends of the armature 12 with the housing 20 with sufficient rigidity, the driving force generated between the armature 12 and the structural portion is transmitted to the housing 20, thereby causing the housing 20 to vibrate. is there.

  FIG. 9 shows a structure in a state in which the drive unit having the structure shown in FIG. 2 and the housing 20 accommodating the whole are removed. FIG. 10 shows a structure in which the housing 20 that accommodates the entire electromechanical converter is integrated. FIG. 9 shows an electromechanical transducer viewed from the same direction as FIG. 2, and an upper housing member 20a and a lower housing member 20b arranged above and below. The upper housing member 20a and the lower housing member 20b are formed in a shape in which the unevenness of each side is fitted to each other, and by fixing them with an adhesive or the like, as shown in FIG. It becomes the integral housing 20 to accommodate. The housing 20 can be formed using, for example, a plastic material or a metal material such as stainless steel on the premise that the strength capable of supporting the drive unit is ensured.

  As shown in FIGS. 9 and 10, a substrate 21 is attached to the side surface of the lower housing member 20b, and is electrically connected to the surface of the substrate 21 with the pair of electrodes 11a of the coil 11 described above. A pair of electrodes 22 is provided. Therefore, wiring (not shown) extending from each electrode 11a of the coil 11 is connected to each electrode 22 through the opening of the housing member 20a. Further, in order to ensure the impact resistance of the electromechanical converter, a plurality of stoppers (not shown) projecting inward are provided on the inner surfaces of the upper and lower housing members 20a and 20b, and the movable range of the drive unit such as the yoke 10 is provided. It is desirable to have a structure that restricts

  Further, as shown in FIG. 9, the lengths of the upper and lower housing members 20 a and 20 b in the X direction coincide with the length of the armature 12 in the longitudinal direction. Then, both end portions of the armature 12 are fixed with an adhesive or the like while being sandwiched between the upper and lower housing members 20a and 20b. The housing 20 has a structure that does not come into contact with the drive unit except for both ends of the armature 12. The joint portion between the armature 12 and the housing 20 needs to have sufficient rigidity so that the vibration generated in the drive unit is reliably transmitted to the housing 20.

  As described above, by adopting the structure of the present embodiment, the armature 12 can be positioned stably without providing a structure for engaging the flat armature 12 with the upper and lower spring members 13. The armature 12 and the spring member 13 are not required to be processed with high precision and fineness, and there are advantages in terms of cost reduction and size reduction of the electromechanical transducer. Further, since the spring member 13 is provided on the side surface of the yoke 10, misalignment or the like due to external force applied to the spring member 13 using the upper and lower surfaces of the yoke 10 protruding from the opening A in the manufacturing process or the like. It can be avoided. In the present embodiment, based on the structure using the flat armature 12 and the pair of spring members 13, the degree of freedom in design of the armature 12 and the impact resistance compared to the conventional U-shaped armature are ensured. As for the improvement, the same effect as the structure of Patent Document 1 can be obtained.

  As mentioned above, although the electromechanical converter which concerns on this invention was demonstrated based on this embodiment, this invention is not limited to the above-mentioned embodiment, A various change can be given in the range which does not deviate from the summary. it can. For example, in the present embodiment, the case where the magnet 14 and the pole piece 15 have substantially the same shape in the X direction and the Y direction has been described. However, if the magnet 14 and the pole piece 15 are arranged so as to face each other in the most shape range, It is not limited to the same shape. In the present embodiment, the case where the spring member 13 having the structure of FIG. 5 is used has been described. However, if the spring member 13 has a function based on the fixed portion P1 and the contact portion P2 of FIG. May be used.

  The electromechanical transducer according to the present invention can also be applied to an electroacoustic transducer that converts an electrical signal into sound and outputs the sound to the outside. Furthermore, the electromechanical transducer according to the present invention can be applied to, for example, a hearing aid worn in a user's concha cavity. Thereby, both the vibration itself of the electromechanical converter and the sound generated by the vibration of the housing can function as a transmission means, and the sound can be transmitted to the user's ear. When such an electromechanical transducer is applied to, for example, a hearing aid worn in the concha cavity, it is desirable that the outer shape of the housing 20 be a shape suitable for wearing the concha cavity.

DESCRIPTION OF SYMBOLS 10 ... Yoke 11 ... Coil 12 ... Armature 13 ... Spring member 14 ... Magnet 15 ... Pole piece 16 ... Air gap 17 ... Pole piece side magnet 20 ... Housing

Claims (6)

In an electromechanical converter that converts electrical signals into mechanical vibrations,
A structure in which at least two pairs of magnets, a yoke for guiding magnetic flux generated by the magnets, and a coil to which the electric signal is supplied are integrally disposed;
The plate-shaped member that penetrates the internal space of the structure part, and two regions where the magnetic fluxes in opposite directions are guided are arranged opposite to each other in the first direction of the plate-shaped member, and the two regions are An armature that constitutes a magnetic circuit through the structure portion and is displaced in a displacement direction based on a magnetic force of the magnetic circuit;
A pair of elastic members respectively disposed on both sides in the displacement direction with respect to the armature and imparting a restoring force to the armature according to a relative displacement of the armature with respect to the structural portion;
With
Electromechanical conversion characterized in that two pairs of plate-shaped pole pieces facing the two pairs of magnets are attached to respective positions facing the two regions on both surfaces of the armature. vessel.   2. The electromechanical transducer according to claim 1, wherein the pole piece has the same shape as viewed from the displacement direction with the magnet facing through the two regions.   3. The electromechanical transducer according to claim 2, wherein a pole piece side magnet is provided on each surface of the pole piece, and the pole piece side magnet has the same shape as the magnet when viewed from the displacement direction.   Each of the pair of elastic members is fixed to a part of the yoke, and a contact part that contacts the both sides of the displacement direction on both sides in the first direction of the armature to apply the restoring force. The electromechanical converter according to claim 1, wherein the electromechanical converter is a spring member having a portion.   5. The electric machine according to claim 4, wherein each of the pair of spring members has an opening that surrounds the yoke, and a part of the yoke protrudes from the opening in the displacement direction. converter. The fixing portions are respectively fixed to protrusions located on both sides of the yoke in the second direction perpendicular to the first direction and the displacement direction across the opening. Item 6. The electromechanical converter according to Item 5.

Images