JP7628406B2 - Electromechanical Converter - Google Patents

Description

The present invention relates to an electromechanical transducer that converts an electrical signal into a mechanical vibration.

Known examples of this type of electromechanical converter include a structural unit that is formed by arranging two pairs of magnets, a yoke that guides the magnetic flux produced by these magnets, and a coil to which an electric signal is supplied, and an armature that passes through the internal space and is supported so that the armature can be displaced by two pairs of elastic members that are symmetrically arranged on either side of the armature (see, for example, Patent Documents 1 and 3), and a similar support by a pair of elastic members (see, for example, Patent Document 2).

The pair or pairs of elastic members (springs) described above are sandwiched between the yoke and the armature and deform, positioning 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 structural (design) central axis 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, etc., the armature may tilt from the central axis and not be positioned correctly. Such tilting of the armature can be suppressed to a certain extent, for example, by adopting a structure that minimizes the moment around the central axis acting on the armature (see technical matters in Patent Document 3).

JP 2015-139041 A JP 2018-186378 A JP 2019-193218 A

The above-mentioned method for reducing the moment that the armature receives around the central axis (Patent Document 3) specifically relates to a structure using two pairs of elastic members (Patent Document 1), and cannot be immediately applied to a 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 forces to the armature at perfectly symmetrical distances from the central axis. In either structure, an imbalance in the forces 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 poor yield (rate of defective products) during the manufacturing process.

The present invention provides technology that reduces adverse effects on performance.

The present invention provides an electromechanical converter. The electromechanical converter has an armature disposed in the internal space of a structural part consisting of a magnet, a yoke, and a coil, and supports the armature so that it can be displaced by the elastic force of an elastic member that is paired with the yoke and sandwiches the armature. In this basic configuration, the electromechanical converter has a unique component, an "abutment portion."

In other words, 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 between them. Therefore, by arranging the range where such a point of application of 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.

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, by arranging the linear contact areas on parallel axes symmetrically with respect to the central axis of the structural portion, the point of application of the force is positioned symmetrical with respect to the central axis, as described above, and concentrated on the parallel axis. This prevents torque around the central axis due to an imbalance in the forces acting between the yoke and the elastic member, and suppresses tilting of the armature, thereby preventing deterioration in the performance of the electromechanical converter and preventing a decrease in yield during the manufacturing process.

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 when 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 allows the contact area between the opposing portion in the curved and bent state (curved surface state) and the curved surface of the "contact portion" to be suitably linear, and the point of application of the force can be concentrated on the contact area.

[Second aspect]
The second mode is a mode in which the "contact portion" comes into contact with the elastic member at an 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 a linear contact area with the elastic member while keeping the shape of the edge, so that the point of application of force can be concentrated on the contact area.

In the second embodiment, the opposing parts are 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 parts, the opening angle θ2 of the edge is smaller (θ1>θ2). Therefore, the leaf spring-like opposing parts come into contact with the sharper edge in the bent state, and the point of application of force can be concentrated at the contact area.

As described above, the present invention can prevent adverse effects on the performance of the electromechanical transducer.

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

Embodiments of the present invention will be described below with reference to the accompanying drawings. The electromechanical transducers shown in the following embodiments can be used to convert electrical signals into mechanical vibrations, and can also be used in electroacoustic transducers such as speakers and earphones that convert electrical signals into sound (acoustics) using mechanical vibrations.

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.

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).

In addition, two magnets 110, 112 are fixed by adhesive to the inner surface of the upper yoke 102 with a gap in the longitudinal direction, and two magnets 114, 116 are fixed by adhesive to the inner surface of the lower yoke 104 with a gap in the longitudinal direction. 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 magnets 112, 116 face each other with opposite poles (south pole - north pole), and the two magnets 110, 112 and magnets 114, 116 arranged side by side in the longitudinal direction on the inner surface 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 conduct the magnetic flux from the two pairs of magnets 110, 114 and 112, 116 in a closed circuit.

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 start and 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 adhesive while being insulated.

The armature 120 is arranged 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 flat with both sides facing 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 parts 120a, 120b with the elastic members 106, 108 are formed on the upper and lower surfaces, respectively.

On the other hand, the upper and lower yokes 102, 104 are formed with abutment portions 102b, 104b on both sides in the longitudinal direction that protrude from the internal space, 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 longitudinal direction of the yokes 102, 104, respectively, and in the center in the lateral direction. This point will be described in more detail later.

The two pairs of upper and lower elastic members 106, 108 are formed by bending thin plate-like spring material, and when used alone, they have an overall notched elliptical shape, or an "ε"-shaped or "3"-shaped cross-sectional shape. Each elastic member 106, 108 contacts the upper and lower yokes 102, 104 at only one point, the abutment portion 102b, 104b, respectively. 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-sectional shape, and the portion corresponding to the bottom of the groove is formed as the opposing portion 106a, 108a that is shaped like a leaf spring.

The elastic members 106, 108 are formed as curved portions 106c, 108c that extend from the central opposing portions 106a, 108a on both sides and are bent into a U-shaped cross section, and the terminal portions connected to the curved portions 106c, 108c are formed as abutment portions 106b, 108b that form a key (Γ) cross section. Each elastic member 106, 108 contacts the armature 120 at two points on each of the upper and lower surfaces at the terminal abutment portions 106b, 108b, 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.

In the completed state of the electromechanical transducer 100, each elastic member 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 arranged with an appropriate gap (air gap) between the structural parts. In the disassembled state of FIG. 2, each elastic member 106, 108 is shown in a deformed state as in FIG. 1, but in the free state (unloaded), the opposing parts 106a, 108a of each elastic member 106, 108 are flat and are not crushed overall, and the opposing parts 106a, 108a and the abutting parts 106b, 108b at the ends are parallel.

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 stainless steel such as SUS301 spring material.

[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).

[Central 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 X-Y axis direction) of the electromechanical transducer 100. As shown in Fig. 3, a horizontal central axis A1 in the longitudinal direction can be defined for 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 (X-Y plane) with the central axis A1 being the common axis.

[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 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 arrow H between the yokes 102, 104, and therefore force imbalance is unlikely to occur in the structure.

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

[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 in Fig. 4 will occur if there is an extremely large imbalance in the forces acting between the upper and lower elastic members 106, 108 and the yokes 102, 104 in the structure of this embodiment, but such an imbalance in forces is usually kept small and will not be a problem even when variations in machining are taken into consideration.

[Central axis A2, A3]
Next, FIG. 5 is a cross-sectional view of the electromechanical transducer 100 at a position along the V-V line in FIG. 1. If FIG. 4 is a vertical cross-sectional view in the longitudinal direction (X-Z axis direction cross-sectional view), FIG. 5 is a vertical cross-sectional view in the lateral direction (Y-Z axis direction cross-sectional view). FIG. 5(A) is a cross-sectional view of the whole, 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 with a vertical central axis A3. It can be seen that the various members constituting the structural part are all symmetrically arranged in the vertical direction (Y-Z 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).

[Armature tilt (3)]
Here, the inclination of the armature 120 in the direction of the arrow L in Fig. 5 (A) (vertical direction) relative to the central axis A2 can be problematic. The inclination of the armature 120 in the direction of the arrow L has the same meaning for the central axis A3, but in terms of the central axis A1, it is a inclination around the central axis A1 (in the direction of rotation). It has already been found that such inclination becomes a problem 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).

The inventors of the present invention have taken into consideration the structural factors that cause the armature 120 to tilt as described above, and have come up with 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 ways:

[First aspect]
5A: In the first embodiment of this structure, the contact portions 102b, 104b of the yokes 102, 104 contact the elastic members 106, 108 with curved surfaces. In other words, if the opposing portions 106a, 108a of the elastic members 106, 108 are flat in a free state (not shown), the contact portions 102b, 104b that contact these portions are formed as curved surfaces rather than flat surfaces. Therefore, the contact areas between the contact portions 102b, 104b and the opposing portions 106a, 108a are linear and extend 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 portions 102b, 104b of the yokes 102, 104 are narrowed and concentrated in a substantially linear manner, 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.

Figure 5 (B): 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, but the radius of curvature R2 of the curved surface formed on the contact portion 102b is made smaller than the radius of curvature R1 that appears 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 point of application of the force F is suppressed to almost zero.

The contact portions 102b, 104b of the yokes 102, 104 are arranged symmetrically above and below 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 from the central axes A1, A3 alternately, and the generation of torque that causes the armature 120 to tilt in the direction of the arrow L shown in Figure 5 (A) can be kept very small.

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

6 (A): In the second embodiment, the yokes 102 and 104 are provided with abutment portions 302b and 304b different from those in the first embodiment, but otherwise are the same as those in the first embodiment. In this second embodiment, the abutment portions 302b and 304b contact the elastic members 106 and 108 at their edges (edges). Similarly, if the opposing portions 106a and 108a are flat in the free state of the elastic members 106 and 108 (not shown), the abutment portions 302b and 304b that contact these are not flat, but are formed in a convex shape (mountain shape) relative to the opposing portions 106a and 108a, and the contact portions are edge-shaped. Therefore, the contact areas between the abutment portions 302b and 304b and the opposing 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 and 108 from contact portions 302b and 304b of yokes 102 and 104 are narrowed and concentrated in a substantially linear fashion, 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 zero, thereby solving the above-mentioned problem.

Figure 6 (B): 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, when the elastic member 106 is in a deformed state, the opposing portion 106a is deformed due to bending, 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 that appears on the opposing 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 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.

The contact portions 302b, 304b of the yokes 102, 104 are arranged symmetrically above and below 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 from the central axes A1, A3 alternately, and the generation of torque that causes the armature 120 to tilt in the direction of the arrow L shown in Figure 6 (A) can be kept very small.

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.

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 gained from the explanation of the first embodiment will be fully utilized below (reference numbers have been changed from the 100s in the first embodiment to the 200s).

In the second embodiment, as seen in Figures 7 and 8, two bent portions 202a, 204a are formed symmetrically on both side edges of the two yokes 202, 204 that are bent in the direction of assembly. 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 (e.g., by laser welding).

In addition, two magnets 210, 212 are fixed by adhesive to the inner surface of the upper yoke 202 with a gap in the longitudinal direction, and two magnets 214, 216 are fixed by adhesive to the inner surface of the lower yoke 204 with a gap in the longitudinal direction. 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 magnets 212, 216 face each other with opposite poles (south pole - north pole), and the two magnets 210, 212 and 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 and 204 conduct the magnetic flux from the two pairs of magnets 210, 214 and 212, 216 in a closed circuit.

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 start and 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 adhesive while being insulated.

The armature 220 is arranged 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 flat with both sides facing 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 parts 220a, 220b with the elastic members 206, 208 are formed on the upper and lower surfaces, respectively.

On the other hand, the upper and lower yokes 202 and 204 are formed with abutment portions 202b and 204b that protrude from the internal space on both sides in the short side direction, and the yokes 202 and 204 come into contact with a pair of elastic members 206 and 208 at the abutment portions 202b and 204b, respectively. These abutment portions 202b and 204b differ from the first embodiment in that they are located on the central axis of the yokes 202 and 204 in the short side direction and in the center in the longitudinal direction. This point will be described further below.

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

In addition, each of the elastic members 206, 208 has both short sides bent relative to the long sides as described above, so that the side edges in the bending direction (side surfaces in the thickness direction) face the armature 220. The center of the short sides of each of the elastic members 206, 208 are formed as abutment parts 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 parts 206b, 208b formed in the center of the short sides, and the upper elastic member 206 contacts the abutment parts 220a on both sides on the upper surface of the armature 220 at the abutment parts 206b on both sides, and the lower elastic member 208 contacts the abutment parts 220b on both sides on the lower surface of the armature 220 at the abutment parts 208b on both sides. 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.

In the second embodiment, in the completed state of the electromechanical transducer 200, each elastic member 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. In the disassembled state of FIG. 8, each elastic member 206, 208 is shown in a deformed state as in FIG. 7, but in the free state (unloaded), the opposing portions 206a, 208a of each elastic member 206, 208 are flat, and their long sides are not flexed or deformed.

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 SUS301 spring material.

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

[Central 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.

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

Figure 10 is a cross-sectional view of the electromechanical transducer 200 taken along line X-X in Figure 7. If Figure 9 is a horizontal cross-sectional view, Figure 10 is a vertical cross-sectional view in the short side direction (cross-sectional view in the Y-Z axis direction). As shown in Figure 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 differs from that of the first embodiment is that the arrangement of the abutment parts 202b, 204b that form the cross section differs by 90° in the horizontal direction from that of the first embodiment. It can also be seen that the members that make up the structural part, such as the yokes 202, 204 and the coil 218, are all symmetrically arranged in the horizontal direction (Y-Z plane) with the central axis A2 in common.

[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) with respect to the central axis A2, and this does not pose a problem.

[Central axis A1, A3]
Next, FIG. 11 is a cross-sectional view of the electromechanical transducer 200 at a position along line XI-XI in FIG. 7. If FIG. 10 is a vertical cross-sectional view in the short side direction (Y-Z axis direction cross-sectional view), FIG. 11 is a vertical cross-sectional view in the long side direction (X-Z 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 in which the area surrounded by the dashed line in FIG. 11 (A) is enlarged. 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 symbol in FIG. 11).

[Armature tilt (3)]
In the second embodiment, the inclination of the armature 220 in the direction of the 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 the 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 listed 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.

The inventors of the present invention have taken into consideration the structural factors that cause the armature 220 to tilt, even when the armature 220 is supported by a pair of elastic members 206, 208 as in the second embodiment, and have come up with a structure that does not cause an imbalance in the forces acting between the yokes 202, 204 and the elastic members 206, 208. The structure is realized in the following manner.

[First aspect]
11A: In the first embodiment of this structure, the contact portions 202b, 204b of the yokes 202, 204 contact the elastic members 206, 208 with curved surfaces. In other words, if the opposing portions 206a, 208a of the elastic members 206, 208 are flat in a free state (not shown), the contact portions 202b, 204b that contact these portions are formed as curved surfaces rather than flat surfaces. Therefore, the contact areas between the contact portions 202b, 204b and the opposing portions 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 portions 202b, 204b of the yokes 202, 204 are narrowed and concentrated substantially linearly, 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 to be almost zero, thereby solving the same problem as described above.

Figure 11 (B): The curved surfaces formed on the contact portions 202b and 204b can be suitably defined according to the following criteria. 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, but the radius of curvature R2 of the curved surface formed on the contact portion 202b is made smaller than the radius of curvature R1 that appears 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 point of application of the force F is suppressed to almost zero.

The contact portions 202b, 204b of the yokes 202, 204 are arranged symmetrically above and below 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 from the central axes A2, A3 alternately, and the generation of torque that causes the armature 220 to tilt in the direction of the arrow L shown in Figure 11 (A) can be kept very small.

[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 in which the area surrounded by the dashed line in Fig. 12(A) is enlarged.

In FIG. 12 (A): In the second embodiment, the yokes 202 and 204 are provided with abutment portions 402b and 404b different from those in the first embodiment, but otherwise are the same as those in the first embodiment. In such a second embodiment, the abutment portions 402b and 404b contact the elastic members 206 and 208 at their edges (edges). Similarly, if the opposing portions 206a and 208a are flat in the free state of the elastic members 206 and 208 (not shown), the abutment portions 402b and 404b that contact them are not flat, but are formed in a convex shape (mountain shape) relative to the opposing portions 206a and 208a, and the contact portions are edge-shaped. Therefore, the contact areas between the abutment portions 402b and 404b and the opposing 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 and 208 from contact portions 402b and 404b of yokes 202 and 204 are narrowed and concentrated in a substantially linear fashion, 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 nearly zero, solving the same problem as above.

Figure 12 (B): The edges formed on the contact portions 402b and 404b can be suitably defined by the following index. Similarly, taking the upper contact portion 402b as an example, when the elastic member 206 is in a deformed state, the opposing portion 206a is deformed due to bending, 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 that appears on the opposing 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 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.

The contact portions 402b, 404b of the yokes 202, 204 are arranged symmetrically above and below 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 from the central axes A2, A3 alternately, and the generation of torque that causes the armature 220 to tilt in the direction of the arrow L shown in Figure 12 (A) can be kept very small.

The above-described embodiments provide the following advantages.
(1) By introducing the first and second structures exemplified in the first embodiment, the inclination 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 converter 100 is improved, thereby solving the problem of adversely affecting the performance of the electromechanical converter 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.

The present invention is not limited to the above-described embodiments and can be implemented in various modifications.

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

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

When the contact portions 102b, 104b, etc. are formed into an edge shape, the opening angle θ2 may be even more acute than in the example, and the edge may not be simply a mountain shape but may have multiple angles.

In addition, 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 the non-contacting portions may be non-curved.

100 Electromechanical converter 102, 104 Yoke 102b, 104b Abutment portion 106, 108 Elastic member 106a, 108a Opposing portion 110, 112, 114, 116 Magnet 118 Coil 120 Armature

Claims (5)

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;
An electromechanical transducer comprising: a contact portion that brings the elastic member into contact with the yoke, the contact portion having a linear contact area with the elastic member. 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. 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. 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. 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 perpendicular to the penetration direction and are parallel to each other.