Electromechanical Converter

Abstract

To provide a technique that can suppress adverse effects on performances.SOLUTION: An electromechanical converter 100 includes: a structure part in which a coil 118 is arranged in an internal space surrounded by yokes 102 and 104 for guiding magnetic fluxes caused by magnets 110 and 114 into a closed circuit pattern; an armature 120 penetrating the inner space of the structure part in a winding direction of the coil 118; and elastic members 106 and 108 for supporting the armature 120, the elastic members being arranged in a pair between the yokes 102 and 104 by sandwiching the armature 120; and contact parts 102b and 104b for bringing the elastic members 106 and 108 and the yokes 102 and 104 into contact with each other linearly along the contact area of the elastic members 106 and 108.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an electromechanical transducer that converts an electrical signal into a mechanical vibration. [Background technology]

[0002] Known examples of this type of electromechanical converter include one in which two pairs of magnets, a yoke that guides the magnetic flux from the magnets, and a coil to which an electric signal is supplied are integrally arranged to form a structural part, with an armature passing through the internal space and supported for displacement by two pairs of elastic members arranged symmetrically on either side of the armature (see, for example, Patent Documents 1 and 3), and one in which the armature is similarly supported by a pair of elastic members (see, for example, Patent Document 2).

[0003] The pair or pairs of elastic members (springs) described above are sandwiched between the yoke and the armature and deform, and position the armature relative to the yoke at a point where their elastic forces (restoring forces) are balanced. At this time, the armature is required to be correctly positioned along the central axis of the structure (design) in relation to the yoke, but if the elastic forces acting on the armature become unbalanced due to variations in the processing accuracy of the elastic members, the armature may tilt from the central axis and not be positioned correctly. Such tilt of the armature can be suppressed to a certain extent, for example, by adopting a structure that minimizes the moment acting on the armature around the central axis (see technical matters in Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-139041 A [Patent Document 2] JP 2018-186378 A [Patent Document 3] JP 2019-193218 A Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned method (Patent Document 3) for reducing the moment that the armature receives around the central axis is specifically related to the structure using two pairs of elastic members (Patent Document 1), and cannot be immediately applied to the structure using a pair of elastic members (Patent Document 2). In addition, since a certain degree of variation is unavoidable in machining, it is difficult to achieve machining with perfect precision that applies elastic force to the armature at a perfectly symmetrical distance from the central axis. In either structure, an imbalance in the force acting between the yoke and the elastic members tilts the armature from its normal position, adversely affecting its performance as an electromechanical transducer, resulting in a problem of poor yield (rate of defective products) in the manufacturing process.

[0006] The present invention provides a technique that reduces the adverse effects on performance. [Means for solving the problem]

[0007] The present invention provides an electromechanical converter. The electromechanical converter has an armature disposed in an internal space of a structural part consisting of a magnet, a yoke, and a coil, and supports the armature so as to be displaceable by the elastic force of an elastic member that is arranged between the armature and the yoke. In this basic configuration, the electromechanical converter has a unique component, an "abutment part."

[0008] That is, the "contact portion" in the above configuration makes the contact area with the elastic member linear, and brings the elastic member into contact (abuts) with the yoke. In this case, the point of application of force between the yoke and the elastic member can be concentrated within a linear range, so the point of application of force does not disperse widely with distance. Therefore, by arranging the range where the point of application of such force is concentrated symmetrically on either side of the armature, the torque of the force that causes the armature to tilt can be kept very small.

[0009] For this reason, it is preferable that the "contact portion" is symmetrical with respect to the central axis of the structural portion, and that the contact areas with the elastic member are arranged on parallel axes. The central axis of the structural portion may be either a central axis along the penetration direction of the armature or a central axis perpendicular to the penetration direction of the armature. In either case, the "contact portion" is arranged symmetrical with respect to the central axis of the structural portion, and the linear contact areas are arranged on parallel axes, so that the force application point is positioned symmetrical with respect to the central axis and concentrated on the parallel axes, as described above. This prevents torque around the central axis due to an imbalance in the forces acting between the yoke and the elastic member, and prevents deterioration in the performance of the electromechanical converter by suppressing tilting of the armature, thereby preventing deterioration in yield during the manufacturing process.

[0010] As for the "contact portion," the following preferable aspects can be adopted in relation to the elastic member. [First aspect] The first mode is a mode in which the "contact portion" comes into contact with the elastic member via a curved surface. That is, the elastic member has a leaf spring-like opposing portion that, when it is sandwiched between the armature and the yoke and deformed, comes into contact with the curved surface of the "contact portion" and exerts an elastic force. In this case, when the elastic member is in a deformed state, the opposing portion is curved and bent, and if the radius of curvature appearing at the opposing portion at this time is R1, the radius of curvature R2 of the curved surface of the "contact portion" is smaller (R1>R2). This makes it possible to suitably make the contact area between the opposing portion in the curved and bent state (curved surface state) and the curved surface of the "contact portion" linear, concentrating the point of application of force on the contact area.

[0011] [Second aspect] The second mode is a mode in which the "contact portion" comes into contact with the elastic member at its edge (end edge). That is, the elastic member has a leaf spring-like opposing portion as in the first embodiment, but the "contact portion" has an edge that is convex with respect to the leaf spring-like opposing portion. In this case, the "contact portion" has an edge shape that makes the contact area with the elastic member preferably linear, and the point of application of force can be concentrated on the contact area.

[0012] In the second embodiment, the opposing portion is curved and bent when the elastic member is deformed, but if the opening angle θ1 is centered on the contact area that appears at the opposing portion, the opening angle θ2 of the edge is smaller (θ1>θ2). Therefore, the leaf spring-like opposing portion comes into contact with the sharper edge in the bent state, and the point of application of force can be concentrated on the contact area. Effect of the Invention

[0013] As described above, according to the present invention, it is possible to suppress adverse effects on the performance of the electromechanical transducer. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing an electromechanical transducer 100 according to a first embodiment. [Diagram 2] FIG. 1 is an exploded perspective view of an electromechanical transducer 100. [Diagram 3] 3 is a cross-sectional view of the electromechanical transducer 100 taken along line III-III in FIG. [Figure 4] 4 is a cross-sectional view of the electromechanical transducer 100 taken along line IV-IV in FIG. [Diagram 5] 2 is a cross-sectional view of the electromechanical transducer 100 taken along line VV in FIG. 1. [Figure 6] FIG. 6 shows a second embodiment of the structure at the same cross-sectional position as FIG. 5. [Figure 7] FIG. 1 is a perspective view showing an electromechanical transducer 200 according to a second embodiment. [Figure 8] FIG. 2 is an exploded perspective view of an electromechanical transducer 200. [Figure 9] 9 is a cross-sectional view of the electromechanical transducer 200 taken along line IX-IX in FIG. 7. [Figure 10] 8 is a cross-sectional view of the electromechanical transducer 200 taken along line XX in FIG. 7. [Figure 11] 10 is a cross-sectional view of the electromechanical transducer 200 taken along line XI-XI in FIG. 7. [Figure 12]FIG. 12 shows a second embodiment of the structure at the same cross-sectional position as in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The electromechanical transducer shown in the following embodiments can be used for converting an electrical signal into mechanical vibration, and can also be used for electroacoustic transducers such as speakers and earphones that convert an electrical signal into sound (acoustics) by the mechanical vibration.

[0016] [First embodiment] Fig. 1 is a perspective view showing an electromechanical transducer 100 of the first embodiment. Fig. 2 is an exploded perspective view of the electromechanical transducer 100. The basic structure of the electromechanical transducer 100 is such that an armature 120 is disposed through an internal space (all without reference numbers) of a structural part in which magnets 110, 112, 114, 116, yokes 102, 104, and a coil 118 are integrally disposed, and the armature 120 is supported by two pairs of elastic members 106, 108 sandwiched between the yokes 102, 104.

[0017] This basic structure is already known, so details will be omitted, but as seen in Figures 1 and 2, two bent portions 102a, 104a bent in the direction of assembly are formed symmetrically on both side edges of the two yokes 102, 104 that form a pair above and below. In the completed state shown in Figure 1, the upper and lower yokes 102, 104 are pressed together at the opposing joint surfaces of these bent portions 102a, 104a and joined together (for example, by laser welding).

[0018] Two magnets 110, 112 are fixed to the inner surface of the upper yoke 102 with a gap in the longitudinal direction by adhesive, and two magnets 114, 116 are fixed to the inner surface of the lower yoke 104 with a gap in the longitudinal direction by adhesive. In the completed state, the rectangular plate-shaped magnets 110, 114 facing each other vertically on one side in the longitudinal direction form one pair, and the rectangular plate-shaped magnets 112, 116 facing each other vertically on the other side form another pair. The paired magnets 110, 114 and the magnets 112, 116 face each other with opposite poles (south pole-north pole), and the two magnets 110, 112 and the magnets 114, 116 arranged side by side in the longitudinal direction on the inner surface of each of the same yokes 102, 104 are magnetized with polarities opposite to each other. As a result, in the completed state, the two yokes 102, 104 guide the magnetic flux generated by the upper and lower pairs of magnets 110, 114 and magnets 112, 116 in a closed circuit.

[0019] The coil 118 is disposed in the center of the longitudinal direction in the internal space surrounded by the yokes 102 and 104, that is, between the pair of magnets 110 and 114 and the pair of magnets 112 and 116. The coil 118 is an air-core type coil that does not have a core, and the direction of the winding center coincides with the longitudinal direction of the entire structure. The outer peripheral surface of the coil 118 is partially exposed on both sides in the short direction (direction perpendicular to the longitudinal direction) of the structure from between the bent portions 102a and 104a, and coil terminals 122 and 124 are soldered to these two exposed locations. The coil terminals 122 and 124 allow the winding start end and winding end end of the coil 118 to be connected to the outside, respectively. The coil 118 is fixed to the inner surface of the yokes 102 and 104 by adhesion in an insulated state.

[0020] The armature 120 is disposed so as to penetrate the internal space of the structural part in the longitudinal direction, i.e., in the direction of the winding core of the coil 118. The armature 120 is in the form of a flat plate whose both sides face the upper and lower rectangular plate-shaped magnets 110, 112 and magnets 114, 116, respectively, and both ends in the longitudinal direction protrude outward from the internal space. At both ends of the protruding armature 120, abutment portions 120a, 120b for engaging with the elastic members 106, 108 are formed on the upper and lower surfaces, respectively.

[0021] Meanwhile, the upper and lower yokes 102, 104 are formed with abutment portions 102b, 104b that protrude from the internal space on both sides in the longitudinal direction, and the yokes 102, 104 come into contact with the elastic members 106, 108 at the abutment portions 102b, 104b, respectively. These abutment portions 102b, 104b are located on the central axis of the yokes 102, 104 in the longitudinal direction and at the center in the lateral direction. This point will be described in more detail later.

[0022] The two pairs of upper and lower elastic members 106, 108 are formed by bending thin plate-like spring members, and when used alone, they have an overall shape such as a notched ellipse, an "ε"-shaped cross section, or a "3"-shaped cross section. Each elastic member 106, 108 contacts the upper and lower yokes 102, 104 at only one point, the abutment portion 102b, 104b. For this reason, the central portion of each elastic member 106, 108 corresponding to the abutment portion 102b, 104b is machined into a groove-shaped cross section, and the portion corresponding to the bottom of the groove is formed as the opposing portion 106a, 108a having a leaf spring shape.

[0023] In addition, each of the elastic members 106, 108 has portions extending from the central opposing portions 106a, 108a on both sides formed as curved portions 106c, 108c bent into a U-shaped cross section, and end portions connected to the curved portions 106c, 108c are formed as abutment portions 106b, 108b each having a key (Γ)-shaped cross section. Each of the elastic members 106, 108 contacts the armature 120 at two points on each of the upper and lower surfaces at the abutment portions 106b, 108b at the ends, with the upper elastic member 106 contacting the abutment portion 120a on the upper surface of the armature 120 at the abutment portion 106b, and the lower elastic member 108 contacting the abutment portion 120b on the lower surface of the armature 120 at the abutment portion 108b.

[0024] In the completed state of the electromechanical transducer 100, each of the elastic members 106, 108 is sandwiched between the upper and lower yokes 102, 104 and the armature 120 with a predetermined amount of displacement (deformation). As a result, the armature 120 is supported at a position where the elastic forces (repulsive forces) of the two pairs of upper and lower elastic members 106, 108 are balanced, and is disposed with an appropriate gap (air gap) between the structural parts. In the exploded state of FIG. 2, the elastic members 106, 108 are shown in a deformed state as in FIG. 1, but in a free state (unloaded), the opposing portions 106a, 108a of the elastic members 106, 108 are flat and are not crushed as a whole, and the opposing portions 106a, 108a and the abutting portions 106b, 108b at the ends are parallel to each other.

[0025] The yokes 102, 104 and the armature 120 are made of a soft magnetic material such as 45% Ni permalloy, and the elastic members 106, 108 are made of a stainless steel material such as SUS301 for springs.

[0026] [Relationship with central axis] Next, a description will be given of the relationship with several central axes defined in the structural portion of the electromechanical transducer 100. When the structural portion is viewed three-dimensionally, the central axes are defined in, for example, three directions (so-called XYZ axes).

[0027] [Center axis A1] Fig. 3 is a cross-sectional view of the electromechanical transducer 100 taken along line III-III in Fig. 1. If the longitudinal direction of the structural part as viewed in Fig. 1 is taken as the horizontal direction, for example, the cross section shown in Fig. 3 is a horizontal cross section (cross section in the XY axis direction) of the electromechanical transducer 100. As shown in Fig. 3, a horizontal central axis A1 in the longitudinal direction can be defined in the structural part of the electromechanical transducer 100. All of the members constituting the structural part, such as the magnets 110, 112, 114, 116, the yokes 102, 104, and the coil 118, are arranged symmetrically in the horizontal direction (XY plane) with the central axis A1 being the common axis.

[0028] [Armature tilt (1)] Regarding tilt of the armature 120, which may adversely affect the performance of the electromechanical transducer 100, the structure makes it difficult for the armature 120 to tilt in the direction of the arrow H in Fig. 3 (horizontal direction) with respect to the central axis A1. This is because the elastic members 106, 108 supporting the armature 120 do not apply force in the direction of the arrow H between the yokes 102, 104, and therefore, in the structure, a force imbalance is unlikely to occur.

[0029] Fig. 4 is a cross-sectional view of the electromechanical transducer 100 taken along line IV-IV in Fig. 1. Whereas Fig. 3 is a horizontal cross-sectional view, Fig. 4 is a vertical cross-sectional view in the longitudinal direction (cross-sectional view in the XZ axis direction). As shown in Fig. 4, it can be seen that the members constituting the structural part, such as the magnets 110, 112, 114, 116, the yokes 102, 104, and the coil 118, are all symmetrically arranged in the vertical direction (YZ direction) with a common central axis A1.

[0030] [Armature tilt (2)] 4 (vertical direction) with respect to the central axis A1, tilting of the armature 120 in the direction of the arrow V occurs when the imbalance of forces acting between the upper and lower elastic members 106, 108 and the yokes 102, 104 in the structure of this embodiment is extremely large, but such an imbalance of forces is usually kept small, so it does not cause a problem even when variations in machining are taken into consideration.

[0031] [Center axis A2, A3] Next, FIG. 5 is a cross-sectional view of the electromechanical transducer 100 at a position along the line VV in FIG. 1. If FIG. 4 is a vertical cross-sectional view in the longitudinal direction (XZ axis direction cross-sectional view), FIG. 5 is a vertical cross-sectional view in the lateral direction (YZ axis direction cross-sectional view). FIG. 5(A) is an overall cross-sectional view, and FIG. 5(B) is a partial cross-sectional view enlarging the area surrounded by the dashed line in FIG. 5(A). As shown in FIG. 5(A), the structural part of the electromechanical transducer 100 can be defined with a horizontal central axis A2 in the lateral direction, and further, a central axis A3 in the vertical direction. It can be seen that the various members constituting the structural part are all symmetrically arranged in the vertical direction (YZ plane) with the central axis A2 and the central axis A3 in common. The central axis A1 in the longitudinal direction is located at the intersection of the central axis A2 and the central axis A3 (no reference symbol in FIG. 5).

[0032] [Armature tilt (3)] Here, the inclination of the armature 120 in the direction of arrow L (vertical direction) in Fig. 5(A) with respect to the central axis A2 can be problematic. The inclination of the armature 120 in the direction of arrow L has the same meaning for the central axis A3, but in terms of the central axis A1, it is an inclination around the central axis A1 (in the direction of rotation). It has already been found that such an inclination becomes problematic mainly when an imbalance in the forces acting between the yokes 102, 104 and the elastic members 106, 108 in the direction of the central axis A2 can occur (see Patent Document 3, a prior art document).

[0033] In consideration of the structural factors that cause the armature 120 to tilt as described above, the inventors of the present invention have realized a structure that does not cause an imbalance in the forces acting between the yokes 102, 104 and the elastic members 106, 108. This structure is realized in the following manner.

[0034] [First aspect] In Fig. 5 (A): the first embodiment of this structure is a structure in which the contact parts 102b, 104b of the yokes 102, 104 contact the elastic members 106, 108 with curved surfaces. In other words, if the facing parts 106a, 108a of the elastic members 106, 108 are flat in a free state (not shown), the contact parts 102b, 104b that contact these parts are formed as curved surfaces rather than flat surfaces. Therefore, the contact areas between the contact parts 102b, 104b and the facing parts 106a, 108a are linear extending in the direction of the central axis A1. As a result, the points of application of the force F acting on the elastic members 106, 108 from the contact parts 102b, 104b of the yokes 102, 104 are substantially narrowed and concentrated in a line, so that the points of application of the force F are not dispersed in the direction of the central axis A2. Therefore, the width between the points of application of the force spreading in the direction of the central axis A2, which was a problem in the prior art (Patent Document 3, etc.), can be made almost zero, thereby solving the above-mentioned problem.

[0035] 5B: The curved surfaces formed on the contact portions 102b and 104b can be suitably defined according to the following criteria. For example, in the case of the upper contact portion 102b, when the elastic member 106 is in a deformed state, the opposing portion 106a is deformed due to bending, and the radius of curvature R2 of the curved surface formed on the contact portion 102b is made smaller than the radius of curvature R1 appearing on the opposing portion 106a in this bending state (R1>R2). As a result, the contact area between the contact portion 102b on the yoke 102 side and the opposing portion 106a of the elastic member 106 is linearly narrowed in the direction of the central axis A2 as described above, and the dispersion of the application point of the force F is suppressed to almost zero.

[0036] Furthermore, the abutment portions 102b, 104b of the yokes 102, 104 are arranged symmetrically above and below about the central axes A1, A2 of the structural portion, so that the force F that the elastic members 106, 108 receive from the upper and lower yokes 102, 104 does not deviate alternately from the central axes A1, A3, and the generation of torque that causes the armature 120 to tilt in the direction of arrow L shown in Figure 5 (A) can be kept extremely small.

[0037] [Second aspect] Fig. 6 is a diagram showing a second embodiment of the present structure at the same cross-sectional position as Fig. 5. Of these, Fig. 6(A) is an overall cross-sectional view, and Fig. 6(B) is a partial cross-sectional view enlarging the area surrounded by the dashed line in Fig. 6(A).

[0038] In FIG. 6A: In the second embodiment, the yokes 102 and 104 are formed with contact portions 302b and 304b different from those in the first embodiment, but otherwise are the same as the first embodiment. In such a second embodiment, the contact portions 302b and 304b contact the elastic members 106 and 108 at their edges (edges). Similarly, if the facing portions 106a and 108a are flat in the free state of the elastic members 106 and 108 (not shown), the contact portions 302b and 304b that contact these are not flat, but are formed in a convex shape (mountain shape) relative to the facing portions 106a and 108a, and the contact portions are edge-shaped. Therefore, the contact areas between the contact portions 302b and 304b and the facing portions 106a and 108a are also linearly extending in the direction of the central axis A1. As a result, the points of application of force F acting on elastic members 106, 108 from abutment portions 302b, 304b of yokes 102, 104, respectively, are substantially narrowed and concentrated in a linear shape, so that the points of application of force F do not disperse in the direction of central axis A2, and similarly, the width between the points of application of the force spreading in the direction of central axis A2 is made almost nonexistent (zero), thereby solving the above-mentioned problem.

[0039] 6B: The edges formed on the contact portions 302b and 304b can be suitably defined by the following index. Similarly, taking the upper contact portion 302b as an example, deformation due to bending occurs in the facing portion 106a when the elastic member 106 is in a deformed state, but the opening angle θ2 of the edge formed on the contact portion 302b is made smaller than the opening angle θ1 centered on the contact area appearing on the facing portion 106a in this bending state (θ1>θ2). As a result, the contact area between the contact portion 302b on the yoke 102 side and the facing portion 106a of the elastic member 106 is linearly narrowed in the direction of the central axis A2 as described above, and the dispersion of the application point of the force F is suppressed to almost zero.

[0040] Furthermore, the abutment portions 302b, 304b of the yokes 102, 104 are arranged symmetrically above and below about the central axes A1, A2 of the structural portion, so that the force F that the elastic members 106, 108 receive from the upper and lower yokes 102, 104 does not deviate alternately from the central axes A1, A3, and the generation of torque that causes the armature 120 to tilt in the direction of arrow L shown in Figure 6 (A) can be kept extremely small.

[0041] Second Embodiment Next, a second embodiment of the electromechanical transducer will be described. Fig. 7 is a perspective view showing an electromechanical transducer 200 of the second embodiment. Fig. 8 is an exploded perspective view of the electromechanical transducer 200. The basic structure of the electromechanical transducer 200 is such that an armature 220 is disposed through an internal space (all without reference numbers) of a structural part in which magnets 210, 212, 214, 216, yokes 202, 204, and a coil 218 are integrally disposed, and the armature 220 is supported by a pair of elastic members 206, 208 sandwiched between the yokes 202, 204.

[0042] As described above, the electromechanical transducer 200 of the second embodiment differs from the first embodiment in that the armature 220 is supported by a pair of elastic members 206, 208. However, since the configuration other than the contact between the elastic members 206, 208 and the yokes 202, 204 has much in common with the first embodiment, the understanding obtained from the explanation of the first embodiment will be fully utilized below (reference numerals in the 100s of the first embodiment have been changed to the 200s).

[0043] In the second embodiment, two bent portions 202a, 204a bent in the combination direction are formed symmetrically on both side edges of two yokes 202, 204 that form a pair vertically as viewed in Figures 7 and 8. In the completed state shown in Figure 7, the upper and lower yokes 202, 204 are pressed together at the opposing joint surfaces of the bent portions 202a, 204a and joined together (for example, by laser welding).

[0044] Two magnets 210, 212 are fixed to the inner surface of the upper yoke 202 with a gap in the longitudinal direction by adhesive, and two magnets 214, 216 are fixed to the inner surface of the lower yoke 204 with a gap in the longitudinal direction by adhesive. In the completed state, the rectangular plate-shaped magnets 210, 214 facing each other vertically on one side in the longitudinal direction form one pair, and the rectangular plate-shaped magnets 212, 216 facing each other vertically on the other side form another pair. The paired magnets 210, 214 and the magnets 212, 216 face each other with opposite poles (south pole-north pole), and the two magnets 210, 212 and the magnets 214, 216 arranged side by side in the longitudinal direction on the inner surface of each of the same yokes 202, 204 are magnetized with polarities opposite to each other. As a result, in the completed state, the two yokes 202, 204 guide the magnetic flux generated by the upper and lower pairs of magnets 210, 214 and magnets 212, 216 in a closed circuit.

[0045] The coil 218 is disposed in the center of the longitudinal direction in the internal space surrounded by the yokes 202 and 204, that is, between the pair of magnets 210 and 214 and the pair of magnets 212 and 216. The coil 218 is an air-core type coil that does not have a core, and the direction of the winding center coincides with the longitudinal direction of the entire structure. The outer peripheral surface of the coil 218 is partially exposed on both sides in the short direction (direction perpendicular to the longitudinal direction) of the structure from between the bent portions 202a and 204a, and coil terminals 222 and 224 are soldered to these two exposed locations. The coil terminals 222 and 224 allow the winding start end and winding end end of the coil 218 to be connected to the outside, respectively. The coil 218 is fixed to the inner surface of the yokes 202 and 204 by adhesion in an insulated state.

[0046] The armature 220 is disposed so as to penetrate the internal space of the structural part in the longitudinal direction, i.e., in the direction of the winding core of the coil 218. The armature 220 is in the form of a flat plate whose both sides face the upper and lower rectangular plate-shaped magnets 210, 212 and magnets 214, 216, respectively, and both ends in the longitudinal direction protrude outward from the internal space. At both ends of the protruding armature 220, abutment portions 220a, 220b for engaging with the elastic members 206, 208 are formed on the upper and lower surfaces, respectively.

[0047] Meanwhile, the upper and lower yokes 202, 204 are formed with abutment portions 202b, 204b protruding from the internal space on both sides in the short side direction, and the yokes 202, 204 come into contact with a pair of elastic members 206, 208 at the abutment portions 202b, 204b, respectively. These abutment portions 202b, 204b are different from the first embodiment in that they are located on the central axis lines in the short side direction of the yokes 202, 204 and in the center in the long side direction. This point will be described in more detail later.

[0048] [Pair of Elastic Members] The pair of upper and lower elastic members 206, 208 used in the second embodiment are formed by punching a thin plate-like spring member into a substantially square ring shape and bending the short sides of both sides relative to the long sides, and the four corners connecting the short sides and the long sides are curved parts 206c, 208c. Each of the elastic members 206, 208 contacts the upper and lower yokes 202, 204 at two points, the contact parts 202b, 204b, respectively, which is also different from the first embodiment. That is, each of the elastic members 206, 208 is formed as a leaf spring-shaped facing part 206a, 208a at the center of the long side corresponding to the contact parts 202b, 204b.

[0049] Moreover, each of the elastic members 206, 208 has both short side portions bent relative to the long side portions as described above, so that the side edge in the bending direction (side surface in the thickness direction) faces the armature 220. The center of the short side portion of each of the elastic members 206, 208 is formed as the abutment portion 206b, 208b. Each of the elastic members 206, 208 contacts the armature 220 at two points on each of the upper and lower surfaces at the abutment portions 206b, 208b formed at the center of the short side portion, and the upper elastic member 206 contacts both abutment portions 220a on the upper surface of the armature 220 at both abutment portions 206b, and the lower elastic member 208 contacts both abutment portions 220b on the lower surface of the armature 220 at both abutment portions 208b. In this way, the contact relationship between the elastic members 206, 208 and the armature 220 in the second embodiment is different from that in the first embodiment.

[0050] In the second embodiment, in the completed state of the electromechanical transducer 200, each of the elastic members 206, 208 is sandwiched between the upper and lower yokes 202, 204 and the armature 220 with a predetermined amount of displacement (deformation). As a result, the armature 220 is supported at a position where the elastic forces (repulsive forces) of the pair of upper and lower elastic members 206, 208 are balanced, and is disposed with an appropriate gap (air gap) between the structural parts. Note that in the exploded state of FIG. 8, each of the elastic members 206, 208 is shown in a deformed state as in FIG. 7, but in a free state (unloaded), the opposing portions 206a, 208a of each of the elastic members 206, 208 are flat, and their long sides are not flexed or deformed.

[0051] In the second embodiment, the yokes 202, 204 and the armature 220 are made of a soft magnetic material such as 45% Ni permalloy, and the elastic members 206, 208 are made of stainless steel such as spring SUS301.

[0052] [Relationship with central axis] Next, a description will be given of the relationship with several central axes defined in the structural portion of the electromechanical transducer 200 in the second embodiment. Note that, like the first embodiment, central axes are defined in, for example, three directions.

[0053] [Center axis A1] Fig. 9 is a cross-sectional view of the electromechanical transducer 200 taken along line IX-IX in Fig. 7. If the longitudinal direction of the structure in Fig. 7 is taken as the horizontal direction, for example, the cross section shown in Fig. 9 is a horizontal cross section (cross section in the XY axis direction) of the electromechanical transducer 200. In the second embodiment as well, a central axis A1 that is horizontal in the longitudinal direction can be defined for the structure of the electromechanical transducer 200.

[0054] [Armature tilt (1)] Similarly, in the second embodiment, the armature 220 is structurally unlikely to tilt in the direction of arrow H (horizontal direction) in Fig. 9 with respect to the central axis A1. This is because the elastic members 206, 208, which also support the armature 220, do not apply force in the direction of arrow H between the yokes 202, 204, and therefore, structurally, a force imbalance is unlikely to occur.

[0055] FIG. 10 is a cross-sectional view of the electromechanical transducer 200 taken along line XX in FIG. 7. If FIG. 9 is a horizontal cross-sectional view, FIG. 10 is a vertical cross-sectional view in the short side direction (YZ axis direction cross-sectional view). As shown in FIG. 10, the structural part can be defined with a horizontal central axis A2 in the short side direction. The reason why the direction of the cross section is different from that of the first embodiment is that the arrangement of the abutment parts 202b, 204b that take the cross section is different by 90° in the horizontal direction from that of the first embodiment. It can be seen that the members that constitute the structural part, such as the yokes 202, 204 and the coil 218, are all symmetrically arranged in the horizontal direction (YZ plane) with the central axis A2 in common.

[0056] [Armature tilt (2)] In the second embodiment, the armature 220 is structurally unlikely to tilt in the direction of arrow V in FIG. 10 (vertical direction) relative to the central axis A2, and this does not pose a problem.

[0057] [Center axis A1, A3] Next, FIG. 11 is a cross-sectional view of the electromechanical transducer 200 at a position along the line XI-XI in FIG. 7. If FIG. 10 is a vertical cross-sectional view in the short side direction (YZ axis direction cross-sectional view), FIG. 11 is a vertical cross-sectional view in the long side direction (XZ axis direction cross-sectional view). Also, FIG. 11(A) is an overall cross-sectional view, and FIG. 11(B) is a partial cross-sectional view enlarging the area surrounded by the dashed line in FIG. 11(A). As shown in FIG. 11(A), the structure can be defined with a horizontal central axis A1 in the short side direction and a vertical central axis A3. The central axis A2 in the short side direction is located at the intersection of the central axis A1 and the central axis A3 (no reference number in FIG. 11).

[0058] [Armature tilt (3)] In the second embodiment, the inclination of the armature 220 in the direction of arrow L (vertical direction) in Fig. 11 (A) with respect to the central axis A1 can be a problem. The inclination of the armature 220 in the direction of arrow L has the same meaning for the central axis A3, but in terms of the central axis A2, it is an inclination around the central axis A2 (in the direction of rotation). According to the knowledge obtained from the technical matters of Patent Document 3, which is cited as a prior art document, it can be seen that such an inclination becomes a problem mainly when an imbalance of forces acting between the yokes 202, 204 and the elastic members 206, 208 in the direction of the central axis A1 can occur.

[0059] Even when the armature 220 is supported by a pair of elastic members 206, 208 as in the second embodiment, the inventors of the present invention have considered structural factors that cause the armature 220 to tilt, and have realized a structure that does not cause an imbalance in the forces acting between the yokes 202, 204 and the elastic members 206, 208. This structure is realized by the following multiple aspects.

[0060] [First aspect] In Fig. 11 (A): the first embodiment of this structure is a structure in which the contact parts 202b, 204b of the yokes 202, 204 contact the elastic members 206, 208 with a curved surface. In other words, if the facing parts 206a, 208a are flat in the free state (not shown) of the elastic members 206, 208, the contact parts 202b, 204b that contact these parts are formed as curved surfaces rather than flat surfaces. Therefore, the contact areas between the contact parts 202b, 204b and the facing parts 206a, 208a are linear extending in the direction of the central axis A2. As a result, the points of application of the force F acting on the elastic members 206, 208 from the contact parts 202b, 204b of the yokes 202, 204 are substantially narrowed and concentrated in a line, so that the points of application of the force F are not dispersed in the direction of the central axis A1. Therefore, when assuming the structure of the second embodiment, the width between the points of application of the force expanding in the direction of the central axis A1, which is a problem in the prior art (Patent Document 3, etc.), can be made almost zero, thereby solving the same problem as described above.

[0061] 11B: The curved surfaces formed on the contact portions 202b and 204b can be suitably defined by the following index. For example, in the case of the upper contact portion 202b, when the elastic member 206 is in a deformed state, the opposing portion 206a is deformed due to bending, and the radius of curvature R2 of the curved surface formed on the contact portion 202b is made smaller than the radius of curvature R1 appearing on the opposing portion 206a in this bending state (R1>R2). As a result, the contact area between the contact portion 202b on the yoke 202 side and the opposing portion 206a of the elastic member 206 is linearly narrowed in the direction of the central axis A1 as described above, and the dispersion of the application point of the force F is suppressed to almost zero.

[0062] Furthermore, the abutment portions 202b, 204b of the yokes 202, 204 are arranged symmetrically above and below about the central axes A1, A2 of the structural portion, so that the force F that the elastic members 206, 208 receive from the upper and lower yokes 202, 204 does not deviate alternately from the central axes A2, A3, and the generation of torque that causes the armature 220 to tilt in the direction of arrow L shown in Figure 11 (A) can be kept extremely small.

[0063] [Second aspect] Fig. 12 is a diagram showing a second embodiment of the present structure at the same cross-sectional position as Fig. 11. Of these, Fig. 12(A) is an overall cross-sectional view, and Fig. 12(B) is a partial cross-sectional view enlarging the area surrounded by the dashed line in Fig. 12(A).

[0064] In FIG. 12(A): In the second embodiment, the yokes 202 and 204 are formed with contact portions 402b and 404b different from those in the first embodiment, but otherwise are the same as the first embodiment. In such a second embodiment, the contact portions 402b and 404b contact the elastic members 206 and 208 at their edges (edges). Similarly, in this embodiment, if the facing portions 206a and 208a are flat in the free state of the elastic members 206 and 208 (not shown), the contact portions 402b and 404b that contact the facing portions 206a and 208a are not flat, but are formed in a convex shape (mountain shape) with respect to the facing portions 206a and 208a, and the contact portions are edge-shaped. Therefore, the contact areas between the contact portions 402b and 404b and the facing portions 206a and 208a are also linearly extending in the direction of the central axis A2. As a result, the points of application of force F acting on elastic members 206, 208 from abutment portions 402b, 404b of yokes 202, 204, respectively, are substantially narrowed and concentrated in a linear shape, so that the points of application of force F do not disperse in the direction of central axis A1, and similarly, the width between the points of application of the force spreading in the direction of central axis A1 is made almost nonexistent (zero), thereby solving the same problem as described above.

[0065] 12B: The edges formed on the contact portions 402b, 404b can be suitably defined by the following index. Similarly, taking the upper contact portion 402b as an example, deformation due to bending occurs in the facing portion 206a when the elastic member 206 is in a deformed state, but the opening angle θ2 of the edge formed on the contact portion 402b is made smaller than the opening angle θ1 centered on the contact area appearing on the facing portion 206a in this bending state (θ1>θ2). As a result, the contact area between the contact portion 402b on the yoke 202 side and the facing portion 206a of the elastic member 206 is linearly narrowed in the direction of the central axis A1 as described above, and the dispersion of the application point of the force F is suppressed to almost zero.

[0066] Furthermore, the abutment portions 402b, 404b of the yokes 202, 204 are arranged symmetrically above and below about the central axes A1, A2 of the structural portion, so that the force F that the elastic members 206, 208 receive from the upper and lower yokes 202, 204 does not deviate alternately from the central axes A2, A3, and the generation of torque that causes the armature 220 to tilt in the direction of arrow L shown in Figure 12 (A) can be kept extremely small.

[0067] The above-described embodiments provide the following advantages. (1) By introducing the first and second structures exemplified in the first embodiment, the tilt of the armature 120 caused by the imbalance of forces acting between the yokes 102, 104 and the elastic members 106, 108 of the electromechanical transducer 100 is improved, thereby solving the problem of adversely affecting the performance of the electromechanical transducer 100 and reducing yields. (2) Although the above describes a structure constituted by two pairs of elastic members 106, 108 as in the first embodiment, the second embodiment can also be applied to a structure constituted by a pair of elastic members 206, 208. This improves the inclination of the armature 220 caused by the imbalance of forces acting between the yokes 202, 204 of the electromechanical transducer 200 and the pair of elastic members 206, 208, and solves the problem of adversely affecting the performance of the electromechanical transducer 200 and reducing the yield.

[0068] The present invention is not limited to the above-described embodiments, and can be practiced in various modified forms.

[0069] In the first embodiment, an example was given in which the facing portions 106a, 108a of the elastic members 106, 108 are formed in a groove shape, but as in the second embodiment, the facing portions 106a, 108a may be flat portions over the entire width.

[0070] In each embodiment, there are no particular restrictions on the shape, size, or details of the various members (magnets, yokes, coils, etc.) that make up the structural portion, and they can be modified or changed as appropriate.

[0071] When the contact portions 102b, 104b, etc. are formed into an edge shape, the opening angle θ2 may be more acute than that in the illustrated example, and the edge may not be a simple mountain shape but may be an edge with multiple angles.

[0072] Furthermore, when the contact portions 102b, 104b, etc. are curved, only the portions that come into contact with the opposing portions 106a, 108a, etc. may be curved, and non-contact portions may be non-curved. [Explanation of symbols]

[0073] 100 Electromechanical Converter 102,104 York 102b,104b Contact part 106, 108 Elastic member 106a, 108a Opposite parts 110,112,114,116 Magnets 118 Coil 120 Armature

Claims

1. A structural part including two pairs of magnets with opposite poles facing each other, a yoke that guides the magnetic flux of the two pairs of magnets in a closed circuit, and a coil disposed in an internal space surrounded by the yoke; an armature disposed to penetrate an internal space of the structural portion in a direction toward a winding core of the coil; a pair of elastic members disposed between the yoke and the armature to support the armature in the internal space; a contact portion that makes a contact area with the elastic member linear and brings the elastic member into contact with the yoke; An electromechanical converter comprising:

2. 2. The electromechanical transducer of claim 1, The elastic member is a leaf spring-shaped opposing portion that contacts the abutment portion when the armature is sandwiched between the armature and the yoke and deformed, The abutment portion is An electromechanical transducer comprising: a curved surface having a radius of curvature smaller than a radius of curvature appearing at the opposing portion when the elastic member is in a deformed state.

3. 2. The electromechanical transducer of claim 1, The elastic member is a leaf spring-shaped opposing portion that contacts the abutment portion when the armature is sandwiched between the armature and the yoke and deformed, The abutment portion is An electromechanical transducer having an edge that is convex with respect to the opposing portion.

4. 4. The electromechanical switch according to claim 3, The edge is An electromechanical transducer having an opening angle smaller than an opening angle centered on the contact area that appears at the opposing portion when the elastic member is deformed.

5. 5. The electromechanical transducer according to claim 1, The abutment portion is An electromechanical transducer, characterized in that the contact area with the elastic member is arranged on axes that are symmetrical about a central axis of the structural part that is along the penetration direction of the armature or a central axis of the structural part that is perpendicular to the penetration direction and are parallel to each other.

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