Electromechanical converter

Abstract

To provide a technique with improved structural arrangement.SOLUTION: An electromechanical converter 100 comprises: a structure portion 120 integrally formed from two pairs of magnets 124, a pair of yokes 122 that guide a magnetic flux caused by the magnets 124, and a coil 128 that is arranged in a space surrounded by the yokes 122 and side plates 126; an armature portion integrally formed from an armature 130 disposed inside the space of the structure portion 120 so as to pass through the coil 128, and housings 110, 112 that internally house the structure portion 120 and the armature 130 in a state of being mutually linked to the armature 130; and leaf springs 140 configured so as to be capable of imparting an elastic restoring force to both the housings 110, 112 and the structure portion 120 in a state of being disposed therebetween, thereby allowing relative vibration between the structure portion 120 and the armature portion.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] As prior art related to this type of electromechanical transducer, for example, a balanced armature type is known. A balanced armature type electromechanical transducer integrally arranges, for example, two pairs of magnets, a pair of yokes that guide the magnetic flux generated by these magnets, and a hollow coil to which an electrical signal is supplied to form a structural part, and penetrates and arranges an armature in its internal space. A structure in which the armature is displaceably supported by an elastic member arranged between the armature and the yoke is common (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] All of the prior art structures are useful in that the restoring force of the elastic member (leaf spring) with respect to the armature arranged in the internal space of the structural part is applied in both directions of vibration, and the posture of the armature can be stably maintained in the space. Moreover, when the electromechanical transducer is used as a vibrator of another device (for example, an acoustic device), in the prior art structure, it is also considered that the arrangement of the leaf spring for applying the restoring force of the armature may restrict the miniaturization and high output of the entire vibrator.

[0005] For example, in the structure of the prior art (Patent Document 1), when the entire vibrator is viewed in a direction perpendicular to the vibration direction of the armature, a space for arranging the leaf spring occupies a certain large portion. Therefore, for the entire vibrator, the magnet and the coil can only be arranged within the limited remaining space. In order to satisfy the required specifications (output performance) of the vibrator after securing these arrangement spaces, the overall size has to be increased to a certain extent. Conversely, if the entire vibrator is to be accommodated within a limited size, since there are restrictions on the arrangement space for the magnet and the coil in the direction perpendicular to the vibration direction as described above, it becomes difficult to obtain a high output commensurate with the required specifications.

[0006] Therefore, the present invention provides a technique with an improved structural arrangement.

Means for Solving the Problems

[0007] The present invention provides an electromechanical transducer. The electromechanical transducer includes a structural part, an armature part, and an elastic member, which are the means for solving the problems. The structural part and the armature part are each integrally formed, and these two elements vibrate relative to each other via the elastic member. The electromechanical transducer of the present invention has a characteristic structure in which the elastic member is arranged between the housing and the structural part. This is a characteristic difference from the structure of the prior art in which the elastic member is arranged between the armature and the structural part.

[0008] That is, in the structures of the prior arts (Patent Documents 1 and 2), the structural part and the armature are housed within the housing, but in both cases, the elastic member is arranged between the structural part and the armature, and in the direction perpendicular to the vibration direction, a large space for arranging the elastic member still occupies a lot of space.

[0009] 〔Basic Structure〕 In contrast, in the basic structure provided by the present invention, the housing and the armature are integrally configured to form an "armature part", and structurally, by disposing an elastic member between the housing and the structural part as an element that relatively vibrates with respect to the "structural part", an elastic restoring force can be imparted to both, thereby allowing relative vibration between the "structural part" and the "armature part". As a result, there is no need to provide a space for disposing the elastic member in a direction perpendicular to the vibration direction, making it possible to achieve miniaturization as a whole and high output according to the required specifications. In the present invention, the housing may be in a form capable of accommodating the structural part inside, or in a form capable of surrounding the structural part in a frame shape, or in other forms.

[0010] When an electromechanical transducer is used as a vibrator, vibration output can be taken out from the housing. At this time, if the housing is used as the output location (output point) of the vibrator, when driving by applying an electrical signal to the coil, the structural part vibrates with respect to the armature part that forms an integral structure with the housing, and the reaction force is transmitted to the housing to output vibration. Such an operating principle is the same in the structures of the prior art (Patent Documents 1 and 2). In this type of electromechanical transducer, usually, at least a gap of about the maximum vibration displacement is required in the vibration direction between the housing and the structural part.

[0011] In the structure of the present invention, only by securing a space slightly larger than the maximum vibration displacement (maximum amplitude) between the housing and the structural part for the portion where the elastic member is disposed between the housing and the structural part, there is no need to secure the space for disposing the elastic member that was secured in the direction perpendicular to the vibration direction in the prior art. For this reason, it is advantageous in that miniaturization of the entire vibrator, particularly miniaturization in the direction perpendicular to the vibration direction, is possible without being restricted by the occupied space of the magnet and the coil in the same direction, and it is possible to meet the requirement for high output.

[0012] The present invention further provides the following structures. 〔First Structure〕 The elastic member may be disposed in a space located in the relative vibration direction between the structural part and the housing (which is an integral component of the armature part; the same applies to the second structure). In this structure, it is clear that the elastic member is not disposed in a direction perpendicular to the vibration direction. By disposing the elastic member in the vibration direction, the space for disposing the elastic member in a direction perpendicular to the vibration direction does not expand. Therefore, the constraints due to the prior art structure are eliminated, and overall miniaturization and high output according to the required specifications can be achieved.

[0013] 〔Second Structure〕 The elastic member may be disposed in each space located on both sides of the relative vibration direction between the structural part and the housing. Also in this structure, it is clear that the elastic member is not disposed in a direction perpendicular to the vibration direction. Further, by disposing the elastic members on both sides of the vibration direction, the elastic members can apply a restoring force from both sides through the housing, and the structural part and the armature part can be returned to the balanced position of the forces in the vibration direction.

[0014] 〔Third Structure〕 The elastic member can be composed of a plurality of compression coil springs whose axes are arranged along the relative vibration direction between the structural part and the armature part. The structural part can have a plurality of recesses capable of receiving each one end portion of the plurality of compression coil springs in the axial direction. Then, the plurality of compression coil springs may be disposed at positions where each other end contacts the housing while each one end is received in an individual recess. Note that this structure can be applied to the basic structure and the second structure.

[0015] 〔Fourth Structure〕 In the third structure, the structural part can include a side plate integrally connected to at least a pair of yokes, and recesses may be formed in this side plate. Thereby, it becomes clearer which part of the structural part the recesses are formed in. According to this fourth structure, it is not necessary to form recesses in driving parts such as yokes, and it does not prevent the realization of a structure that satisfies the required specifications regarding the arrangement of driving parts.

Advantages of the Invention

[0016] According to the present invention as described above, it is possible to provide a technique with an improved structural arrangement.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The electromechanical transducer shown in several embodiments below can be applied to, for example, speakers, earphones, and other electroacoustic transducers that convert mechanical vibrations into sound (acoustics) in addition to applications that convert electrical signals into mechanical vibrations, but is not limited to these applications.

[0019] 〔First Embodiment〕 FIG. 1 is a perspective view showing the electromechanical transducer 100 of the first embodiment. FIG. 2 is an exploded perspective view of the electromechanical transducer 100. For convenience in the following description, arrow lines representing the three directions of the X - Y - Z axes are shown in the figure. Among them, the X - axis direction is called the left - right direction, the Y - axis direction is called the front - back direction, and the Z - axis direction is called the up - down direction. Also, in the following description, the up - down direction may be referred to as the vertical direction, the left - right direction as the horizontal direction, the front as the front side, the back as the back side, etc. In this example, (A) in FIG. 1 is a front - upper - right perspective view of the electromechanical transducer 100, and (B) in FIG. 1 is a rear - upper - left perspective view. Also, FIG. 2 is a front - upper - right exploded perspective view of the electromechanical transducer 100. Note that the directions referred to here do not always coincide with the directions in the usage form of the electromechanical transducer 100 (the same applies to other embodiments).

[0020] 〔Basic Structure〕 In the completed state shown in FIG. 1, the electromechanical transducer 100 is mainly composed of two upper and lower housings 110 and 112 in terms of its external form. However, as shown in the exploded state in FIG. 2, a large number of component parts are housed inside the housings 110 and 112. Note that even in the completed state, some component parts such as the electrical terminals 150 are exposed to the outside.

[0021] As shown in FIG. 2, the electromechanical transducer 100 is composed of a large number of element parts that are substantially symmetric in the vertical, horizontal, front, and back directions. Among these, a structural part 120 integrally formed from a plurality of element parts is taken as the basic structural element unit. In addition, an armature part (not shown by a reference numeral for the whole) integrally formed from two upper and lower housings 110 and 112 and an armature 130, and two upper and lower leaf springs 140 (elastic members) are each taken as the basic structural element unit. In FIG. 2, for convenience of illustration, the armature 130 is located within the range showing the structural part 120, but the armature 130 is not included in the structural part 120.

[0022] The basic structure of such an electromechanical transducer 100 is configured such that the armature 130 disposed through the internal space of the structural part 120 is integrated with the housings 110 and 112 to form an armature part, and leaf springs 140 are respectively disposed and sandwiched between the upper and lower housings 110 and 112 and the structural part 120, enabling the elastic restoring force to be applied to both the housings 110 and 112 and the structural part 120. As a result, relative vibration (here, vertical vibration) between the structural part 120 and the armature part is allowed in the completed state. This will be described in more detail below.

[0023] 〔Structural Part〕 The structural part 120 is mainly composed of two pairs of upper and lower magnets 124, a pair of upper and lower yokes 122, a pair of left and right side plates 126, and a hollow coil 128. Among these, the two pairs of upper and lower magnets 124 are in the shape of rectangular flat plates and face each other vertically. Also, the pair of upper and lower yokes 122 are also in the shape of rectangular flat plates, and through-holes 122a are formed in the center in the thickness direction (here, the vertical direction). In addition, protruding portions 122b that protrude laterally are formed on both left and right side surfaces respectively. The pair of left and right side plates 126 are groove-shaped members with a U-shaped vertical cross-section extending in the front-rear direction. Through-holes 126a are formed in the center in the thickness direction (here, the left-right direction). In addition, concave portions 126b that are recessed inward are formed on the upper and lower end surfaces that face each other in the left-right direction respectively. The coil 128 has terminals 128a adhered to both side surfaces. The start and end of the coil winding are soldered to each terminal 128a, and lead wires (not shown) are soldered thereto respectively.

[0024] Also, the structural part 120 includes a pair of upper and lower pivots 129. These pivots 129 are integrally composed of a cylindrical part and a rectangular plate-shaped part. In the completed state, the cylindrical part of each pivot 129 is fitted into the through-hole 122a of the yoke 122. Note that the structure of the pivot 129 may be substituted by a method of welding a spring and a yoke.

[0025] 〔Armature part〕 The armature part is composed of a flat armature 130 and two upper and lower housings 110, 112. Protruding portions 130a that protrude in the front-rear direction are formed on the front and rear end surfaces of the armature 130 respectively. Note that the armature 130 is arranged to penetrate through the inside of the coil 128 in the winding center direction (here, the front-rear direction).

[0026] The upper and lower housings 110 and 112 are combined with each other to form a box shape, and a structural part 120 is accommodated inside. Further, in each of the housings 110 and 112, notch portions 110a and 112a having a concave shape are formed at two positions before and after the end faces that are mating surfaces with each other. In the combined state with each other, the protruding portion 130a of the armature 130 is sandwiched and fixed in the notch portions 110a and 112a, and while the leaf springs 140 are arranged between the structural part 120, they are pressed from above and below. Also, the outer shape of the housing may be a shape suitable for the application and is not limited to a box shape.

[0027] 〔Elastic member〕 Both of the upper and lower leaf springs 140 can impart an elastic restoring force in the vertical direction. In the state of being pressed against the upper and lower housings 110 and 112 as described above, they come into contact with the inner surfaces (the back surface and the bottom surface) of the housings 110 and 112 and the upper and lower surfaces of the structural part 120 (yoke 122). Each leaf spring 140 has a rectangular base portion 140a at the central portion in the front-rear and left-right directions, and plate piece portions 140c in the shape of strips extend in four directions from the four sides of this base portion 140a. Further, each plate piece portion 140c is bent (curled) into a small-diameter partial cylindrical shape at the intermediate point from the base portion 140a to the tip, and the whole is bent into a U shape. In addition, in the state where the four plate-like portions 140c are extended, the leaf spring 140 has a cross shape when viewed from above. Also, a square hole 140b penetrating in the thickness direction is formed at the center of the base portion 140a, and in the completed state, the rectangular plate-like portion of the pivot 129 described above is fitted into the square hole 140b.

[0028] 〔Others〕 In addition, the electromechanical transducer 100 has electrical terminals 150, which are attached to the front surfaces of the housings 110 and 112 in the completed state. A lead wire (not shown) of the coil 128 is soldered to the electrical terminal 150, enabling an electrical signal to be input to the coil 128 from the outside. In the lower housing 112, extraction portions 112b each having a U shape are formed on both sides of the notch portion 112a. In the completed state, a lead wire (not shown) of the coil 128 is drawn out through these extraction portions 112b and soldered to the electrical terminal 150.

[0029] Figure 3 is a perspective view showing the assembled state of the structural portion 120 and the internal arrangement of the leaf spring 140. Among them, (A) in Figure 3 shows the relationship between the assembled structural portion 120 and the armature 130, and (B) in Figure 3 shows the arrangement relationship of the leaf spring 140 between the housings 110 and 112 and the structural portion 120.

[0030] In Figure 3(A): The structural portion 120 has a structure in which two pairs of upper and lower magnets 124 are adhered and fixed to the inner surfaces of the upper and lower yokes 122 respectively, the coil 128 is arranged at the center in the front-rear direction, and then the upper and lower yokes 122 are sandwiched between a pair of left and right side plates 126 and integrated. For the yoke 122, a soft magnetic material such as permalloy with 45% Ni is used. Also, for the magnet 124, a relatively strong type of magnet such as a neodymium magnet or a samarium cobalt magnet is used. Two magnets 124 are fixed by adhesion or the like at intervals in the front-rear direction on the lower surface of the upper yoke 122 and the upper surface (both inner surfaces) of the lower yoke 122 respectively. As a result, in the front-rear direction, two magnets 124 are arranged in pairs, one above the other.

[0031] The coil 128 is manufactured, for example, by winding a self-fusing copper wire. In order to give the two lead wires (not shown) flexibility so as not to interfere with the vibration of the structure 120, a stranded wire using, for example, a thin copper wire with an insulating film is used. Further, the coil 128 is disposed in an internal space surrounded by the upper and lower yokes 122 and the left and right side plates 126, and between the front and rear magnets 124. The coil 128 is of an air-core type without a core, and the direction of its winding center coincides with the front-rear direction. Note that the coil 128 is fixed to the inner surface of the yoke 122 by adhesion in an insulated state. Further, the upper and lower pivots 129 are fixed by adhesion or the like with a cylindrical portion fitted into the through holes 122a of the corresponding yokes 122, and the rectangular portions protrude vertically from the yokes 122. For the pivots 129 and the side plates 126, a steel material such as SUS316L, which is a non-magnetic material, is used, for example. Thereby, the upper and lower yokes 122 including the pivots 129, the upper and lower pairs of magnets 124, the left and right side plates 126, and the coil 128 are integrally configured as the same single structure.

[0032] In FIGS. 3(A) and 3(B): The armature 130 is disposed so as to penetrate the internal space of the structure 120 in the front-rear direction, that is, in the direction of the winding center of the coil 128. The armature 130 is disposed with both sides facing the upper and lower magnets 124, respectively, and the front and rear protruding portions 130a are disposed so as to protrude outward from the internal space.

[0033] In the completed state of the electromechanical transducer 100, the upper and lower leaf springs 140 sandwich the upper and lower housings 110, 112 and the structural part 120, that is, between the upper and lower yokes 122, with a predetermined displacement amount (deformation amount) in a state where the rectangular plate-shaped part of the pivot 129 is fitted into the square hole 140b as described above. As a result, the structural part 120 is supported at a position where these forces are balanced while receiving the elastic force (restoring force) of the upper and lower leaf springs 140, and is arranged with an appropriate interval between the upper and lower housings 110, 112. In the exploded state shown in (B) in FIGS. 2 and 3, each leaf spring 140 is shown in a non-deformed state, but in the assembled state (see FIG. 4), each leaf spring 140 is assembled in a deflected state with deformation in the vertical direction. Note that a plate material such as SUS301 for springs is used for the leaf spring 140. Further, by fitting the square hole 140b to the rectangular plate-shaped part of the pivot 129, the rotational displacement around the vertical axis (Z-axis) in the housings 110, 112 is suppressed for the leaf spring 140.

[0034] Then, the upper and lower housings 110, 112 press and deform each leaf spring 140, and the front and rear protruding parts 130a of the armature 130 are respectively arranged in the front and rear notches 110a, 112a and clamped from above and below, and the protruding part 130a and the notches 110a, 112a are fixed together with the joint of the upper and lower housings 110, 112 by laser welding or the like. As a result, the upper and lower housings 110, 112 and the armature 130 are integrally configured as an armature part that is the same single structure. Here, the term "integrally" means that in the frequency range targeted by the electromechanical transducer 100, its movement behaves as a rigid body, and the same meaning applies to the above-described structural part 120.

[0035] When the structural part 120 and the armature part are integrally configured as described above, and the electrical terminal 150 including the lead wire is attached, the electromechanical transducer 100 reaches the completed state shown in FIG. 1.

[0036] 〔Internal Structure〕 FIG. 4 is a longitudinal sectional view of the electromechanical transducer 100 in a completed state (sectional view taken along line IV-IV in (A) of FIG. 1). Further, FIG. 5 is a longitudinal sectional view of the electromechanical transducer 100 in a completed state (sectional view taken along line V-V in (A) of FIG. 1).

[0037] In the completed state of the electromechanical transducer 100, the same force acts on the upper and lower leaf springs 140 placed between the upper and lower housings 110, 112 and the structural part 120, and since the two leaf springs 140 are composed of the same component parts, the displacement amounts of the respective leaf springs 140 within the housings 110, 112 are also substantially equal. Therefore, in a state where the elastic restoring forces applied from the upper and lower leaf springs 140 to the structural part 120 are balanced, as shown in FIG. 4, the armature 130 is arranged at the center of the housings 110, 112 in the vertical direction, whereby the armature 130 is also positioned substantially at the center in the vertical direction with respect to the internal space of the structural part 120, and the upper and lower gaps 160, 162 between the armature 130 and the structural part 120 in the internal space are substantially equal. As shown in FIG. 4, a slight gap is secured between the side plate 126 of the structural part 120 and the housings 110, 112 in the X-axis direction so as not to interfere with vibration.

[0038] 〔Operating Principle〕 The electromechanical transducer 100 is completed by magnetizing each magnet 124 and adjusting, as necessary, to balance the magnetic forces acting on the armature 130 from the upper and lower magnets 124. The electromechanical transducer 100 constitutes a magnetic circuit with four magnets 124, two upper and lower yokes 122, a coil 128, an armature 130, and four gaps 160, 162 in the upper, lower, front, and rear. At this time, regarding the magnetization direction of the magnets 124, the pairs that are opposite in the vertical direction are magnetized in the same direction, and the adjacent ones in the front-rear direction are magnetized in the opposite direction. For example, as shown by the white arrows in FIG. 5, assume that both pairs of the front-side magnets 124 are magnetized upward, and both pairs of the rear-side magnets 124 are magnetized downward. In such a magnetization pattern of the magnets 124, when a current in a predetermined direction flows from the electrical terminal 150 to the coil 128 and magnetic flux is generated from the front to the rear of the armature 130, the magnetic flux between the lower magnet 124 and the upper magnet 124 decreases at the front while increasing between the lower magnet 124 and the upper magnet 124. Similarly, at the rear, the magnetic flux between the lower magnet 124 and the upper magnet 124 increases while decreasing between the lower magnet 124 and the upper magnet 124. As a result, a magnetic force acts to relatively displace the structural part 120 upward with respect to the armature 130 and the housings 110, 112 integrated therewith, and the displacement amount of the upper leaf spring 140 increases while the displacement amount of the lower leaf spring 140 decreases.

[0039] At this time, considering the armature part with the armature 130 and the housings 110, 112 as an integrated structure, a downward force corresponding to the difference in the elastic restoring forces generated by the upper leaf spring 140 and the lower leaf spring 140 acts on the structural part 120 from the leaf spring 140, and the structural part 120 is relatively displaced within the housings 110, 112 until this force and the upward magnetic force are balanced.

[0040] Then, by passing an alternating current from the electrical terminal 150 to the coil 128, the structural part 120 vibrates vertically within the housings 110 and 112, and a reaction force on the housings 110 and 112 acts therefrom, causing the housings 110 and 112 to also vibrate. In this case, the greater the acting force between the structural part 120 and the armature part, the more the electromechanical transducer 100 can function as a higher-output vibrator.

[0041] 〔Summary of the First Embodiment〕 According to the electromechanical transducer 100 of the first embodiment as described above, the following utilities can be obtained. (1) When making the electromechanical transducer 100 function as a vibrator, there is no need to secure space for arranging the leaf spring 140 in the horizontal direction (here, the front-rear direction or the left-right direction) perpendicular to the vibration direction, and by arranging the leaf spring 140 in the space (the space between the housings 110 and 112 and the structural part 120) that is essential for vibration displacement in the vibration direction, by adding only a slight additional amount to the minimum space required for displacement, this can be used as the arrangement space for the leaf spring 140. Therefore, it is only necessary to slightly increase the size in the vertical direction (here, the height and thickness direction), and since the front-rear direction can be significantly reduced, the overall size of the electromechanical transducer 100 can be reduced.

[0042] (2) Even if the overall size of the electromechanical transducer 100 is reduced, there are no restrictions on the occupied space for arranging the magnet 124 and the coil 128 due to this, so it can be expected to be miniaturized and have high output without reducing the vibration output.

[0043] 〔Second Embodiment〕 Next, a second embodiment of the electromechanical transducer will be described. The second embodiment is particularly suitable for use as a vibrator for vibrations in the frequency range of 100 Hz or less, and is also effective when adding mass for the purpose of ensuring a large vibration output (driving force) in the low-frequency range. The following will be specifically described.

[0044] FIG. 6 is a perspective view showing the electromechanical transducer 200 of the second embodiment. FIG. 7 is an exploded perspective view of the electromechanical transducer 200. In the second embodiment, element parts equivalent to those in the first embodiment are numbered in the 200s, and the last two digits are made common to facilitate understanding of the correspondence with the element parts of the first embodiment. FIG. 8 is a perspective view showing the soldering mode of the lead wire 228b to the coil 228, and FIG. 9 is a perspective view showing the assembled state of the structural part 220 and the internal arrangement of the compression coil spring 240. Hereinafter, the description will focus on the points that are significantly different from the first embodiment, and redundant descriptions including the materials used will be omitted for the element parts that are substantially common to the first embodiment.

[0045] 〔Basic Structure〕 Regarding the electromechanical transducer 200 of the second embodiment as well, the three basic structural element units are the same, but in the second embodiment, the element parts of the structural part 220 are different. Also, in the second embodiment, a compression coil spring 240 is used as the elastic member instead of the leaf spring 140, which is different.

[0046] 〔Structural Part〕 The structural part 220 has two pairs of upper and lower magnets 224, one pair of upper and lower yokes 222, and a coil 228, which is the same as in the first embodiment. However, the element part corresponding to the side plate 126 in the first embodiment is composed of a first side plate 226 and a second side plate 227, which is different.

[0047] The first side plate 226 is formed by, for example, pressing and bending a plate material. A rectangular opening 226a is formed in the center, and a plurality of bent pieces (not shown) are formed at various positions on the periphery and four corners of the opening 226a. The left and right ends of the coil 228 are inserted into the opening 226a in the assembled state, and as shown in FIG. 8, the lead wire 228b is soldered to the terminals 228a on both sides in this inserted state.

[0048] The second side plate 227 has an outer diameter that is rectangular when viewed from the left - right direction, and has a rectangular opening 227a at the center, similar to the first side plate 226, thus forming an angular - ring shape as a whole. Also, by giving the second side plate 227 a certain thickness in the left - right direction, it becomes an element part that functions as a weight (mass) of the vibrator. For such a second side plate 227, for example, brass or the like, which is a non - magnetic material, can be used.

[0049] The second side plates 227 are combined with the first side plate 226 from both the left and right sides, and they are fixed to each other by adhesion to become integral. On the inner surfaces of the left and right second side plates 227 that face each other, groove portions 227c are formed. The groove portions 227c extend in a rib - like shape in the front - rear direction across the opening 226a. The lead wire 228b of the coil 228 soldered to the terminal 228a as described above is inserted into the groove portion 227c, enabling forward drawing - out guidance.

[0050] Furthermore, on the second side plate 227, four recesses 227b are formed at the front - rear end positions of the upper and lower end faces respectively. These recesses 227b are all circular holes with bottoms, and their inner diameters are set to be slightly larger than the outer diameter of the compression coil spring 240. As a result, each recess 227b can receive one end portion of the compression coil spring 240 inside it. Note that the manner of receiving the compression coil spring 240 into the recess 227b will be described later with reference to another drawing.

[0051] 〔Armature part〕 Also in the second embodiment, the point of integrating the armature 230 and the upper and lower housings 210, 212 to form the armature part is the same as in the first embodiment. However, in the second embodiment, a part corresponding to the notch is not formed in the upper housing 210. Therefore, the difference is that the protrusion 230a of the armature 230 is received in the notch 212a of the lower housing 212. Note that in the second embodiment, a notch may also be formed in the upper housing 210. Also, as shown in the armature 230, a through - hole in the thickness direction (here, the up - down direction) may be formed at the center.

[0052] 〔Elastic member〕 In the second embodiment, a compression coil spring 240 is used as the elastic member. A total of eight compression coil springs 240, four on the upper and lower sides respectively, are used. One end of each compression coil spring 240 is inserted into the recess 227b of the second side plate 227 as described above. For the compression coil spring 240, a spring material such as SUS301 can be used, for example.

[0053] As shown in FIG. 9, in the structural part 220 of the second embodiment, second side plates 227 are respectively located on the left and right sides. With the compression coil springs 240 inserted into the recesses 227b of the second side plates 227 respectively, the compression coil springs 240 are arranged between the structural part 220 and the upper and lower housings 210, 212, and each compression coil spring 240 is compressed and deformed in the vertical direction by these. The protruding part 230a of the armature 230 is arranged in the notch 212a and clamped from above and below by the housings 210, 212, and these are fixed by laser welding or the like.

[0054] 〔Internal structure〕 FIG. 10 is a longitudinal sectional view (X-X sectional view in (A) in FIG. 6) of the electric-mechanical converter 200 in a completed state. Further, FIG. 11 is a longitudinal sectional view (XI-XI sectional view in (A) in FIG. 6) of the electric-mechanical converter 200 in a completed state.

[0055] In the completed state of the electromechanical converter 200, the same force acts on the four compression coil springs 240 above and below placed between the upper and lower housings 210, 212 and the structural part 220, and since the total eight compression coil springs 240 are composed of the same component parts, the displacement amounts of the respective compression coil springs 240 within the housings 210, 212 are also substantially equal. Therefore, in a state where the elastic restoring forces applied from the four compression coil springs 240 above and below to the structural part 220 are balanced, as shown in FIG. 10, the armature 230 is arranged at the center of the upper and lower housings 210, 212 in the vertical direction, so that the armature 230 is also positioned substantially at the center in the vertical direction with respect to the internal space of the structural part 220, and the upper and lower gaps between the armature 230 and the structural part 220 in the internal space are substantially equal. Note that, as shown in FIG. 10, a slight gap is secured between the second side plate 227 of the structural part 220 and the housings 210, 212 so as not to impede vibration.

[0056] Here, it can be seen that each recess 227b of the second side plate 227 is deeply counterbored to a position substantially close to the center from the vertical direction. Thereby, by enabling the compression coil spring 240 to be deeply received in the axial direction, it is possible to suitably prevent the buckling deformation of the compression coil spring 240 in the compression displacement state.

[0057] 〔Operating principle〕 As shown in FIG. 11, the operating principles due to the magnetization of the magnet 224 and the application of current are the same as those in the first embodiment, and thus redundant explanations are omitted here.

[0058] 〔Summary of the second embodiment〕 According to the electromechanical converter 200 of the second embodiment, the following utilities can be obtained. (1) By adding the second side plate 227 as a weight, it is possible to improve the output in a low frequency range of, for example, 100 Hz or less. (2) Further, by forming the recess 227b in the second side plate 227 that functions as a weight, the compression coil spring 240 having a certain free length can be accommodated by being sunk into the recess 227b. Therefore, it is not necessary to secure the displacement space of the compression coil spring 240 in the vertical direction from the structural part 220, and the electromechanical transducer 200 can be configured compactly without increasing the thickness (height) in the vibration direction as a whole.

[0059] (3) In the second embodiment, it is not necessary to separately secure a space for arranging the elastic member in the horizontal direction (here, the front-rear direction) perpendicular to the vibration direction. By accommodating most of the total length of the compression coil spring 240 in the second side plate 227, only a part of it needs to protrude vertically from the structural part 220. Thereby, by adding only a slight additional amount to the minimum space required for displacement, this can be used also as the arrangement space of the compression coil spring 240. Therefore, it is only necessary to slightly increase the size in the vertical direction (here, the height / thickness direction), and since it can be significantly reduced in the front-rear direction, the electromechanical transducer 200 as a whole can be miniaturized.

[0060] (4) Even if the whole of the electromechanical transducer 200 is miniaturized, there is no restriction on the occupied space for arranging the magnet 224 and the coil 228 due to this, and it can be expected to be miniaturized and have high output without reducing the vibration output.

[0061] In the second embodiment, the first side plate 226 and the second side plate 227 may be an integral component made of one part, and a similar recess may be provided in this component to accommodate the compression coil spring 240.

[0062] In the first and second embodiments, the coils 128 and 228 are integrally formed with the structural parts 120 and 220 respectively. However, by reducing the dimensions of the hollow parts of the coils 128 and 228, the coils 128 and 228 may be integrally formed with the armatures 130 and 230 by adhesion or the like. In this case, a structure can be adopted in which an appropriate gap is secured between the coils 128 and 228 and the structural parts 120 and 220 so as not to interfere with the vibration.

[0063] That is, if the masses of the entire electro-mechanical converters 100 and 200 (vibrators) are the same, usually, it is often advantageous to relatively reduce the mass on the armature 130 and 230 sides and relatively increase the mass on the structural parts 120 and 220 sides, such as being able to increase the output as a vibrator. Therefore, in the first and second embodiments, the coils 128 and 228 are configured to be integral with the structural parts 120 and 220 sides. However, depending on other requirements, the coils 128 and 228 may also be configured to be integral with the armature 130 and 230 sides. Thus, in this structure, there may also be an embodiment in which the structural part does not include a coil and the armature part includes a coil and is integrally configured.

[0064] 〔Third Embodiment〕 Next, a third embodiment of the electro-mechanical converter will be described. The third embodiment is suitable for using the mechanical vibration converted from an electrical signal to drive, for example, a diaphragm of a speaker or the like.

[0065] FIG. 12 is a perspective view showing the electro-mechanical converter 300 of the third embodiment. FIG. 13 is a partial cross-sectional view including the internal structure of the electro-mechanical converter 300. FIG. 14 is a diagram showing an application example. Similarly in the third embodiment, elements and components equivalent to those listed in the first embodiment are numbered in the 300s, and by making the last two digits the same, it is easier to understand the correspondence with the elements and components of the first embodiment. Hereinafter, the description will focus on the points that are significantly different from the first and second embodiments, and the description of the elements and components that are substantially common to the first and second embodiments, including the materials used, will be omitted as redundant.

[0066] As shown in FIGS. 12 and 13, for the electro-mechanical converter 300 of the third embodiment as well, the yoke 322, the coil 328, the magnet 324, the side plate 326, the electrical terminal 350, lead wires (not shown), etc. are assembled in the same structure as in the first embodiment.

[0067] In the third embodiment, a first elastic member 342 is disposed between the upper and lower housings 310 and 312 without structurally integrating them. Also, the upper yoke 322 and the upper housing 310 are fixed and integrated by laser welding or the like, and a second elastic member 344 is disposed between the lower yoke 322 and the lower housing 312.

[0068] 〔Structural part〕 In the third embodiment, the structural part 320 (not numbered in FIG. 13) is composed of the yoke 322, the coil 328, the magnet 324, the side plate 326, and the upper housing 310. Therefore, in an application example, the upper housing 310 is used as the first structural member 530.

[0069] 〔Armature part〕 The armature part is composed of the armature 330 and the lower housing 312. The lower housing 312 is coupled to the lower yoke 322, which is an element of the structural part 320, via the second elastic member 344. Further, the lower housing 312 is coupled to the upper housing 310 (the first structural member), which is an element of the structural part 320, via the first elastic member 342.

[0070] 〔Operating principle〕 The electromechanical transducer 300 of the third embodiment is characterized in that it has a structure in which, with the lower housing 312 fixed, the upper housing 310, which is the first structural member 530, is directly vibrated, or with the upper housing 310, which is the first structural member 530, fixed, the lower housing 312 is directly vibrated.

[0071] Here, two first elastic members 342 and second elastic members 344 are used, but by appropriately selecting the material, only one of them can be used. That is, since the first elastic member 342 and the second elastic member 344 are compressed simultaneously and pulled simultaneously during operation, either one of them may be used. At this time, since the first and second elastic members 342 and 344 need to be able to impart a restoring force not only during compression but also during tension, no matter which of the first and second elastic members 342 and 344 is used, it is necessary to be fixed to both the structural part 320 and the armature part.

[0072] 〔Application Example〕 Hereinafter, the application example shown in FIG. 14 will be described. (A) in FIG. 14: An example in which the electromechanical transducer 300 of the third embodiment is applied to a speaker 500. The speaker 500 generally includes a speaker housing 510, a damper 520, a diaphragm 530, etc. as components. When driving such a speaker 500 with the electromechanical transducer 300 of the third embodiment, the following two modes (the first mode and the second mode) can be considered.

[0073] 〔The First Mode〕 (B) in FIG. 14: In the first mode, the speaker housing 510 becomes a structure corresponding to the lower housing 312, the damper 520 becomes a structure corresponding to the first elastic member 342, the diaphragm 530 becomes a structure corresponding to the upper housing 310 (the first structural member), and the diaphragm 530 and the structural part 320 are fixed. Therefore, the electromechanical transducer 300 as a vibrator can vibrate the diaphragm 530 (the first structural member) by vibrating the structural part 320 with respect to the speaker housing 510 (the lower housing 312).

[0074] At this time, the speaker housing 510 (the lower housing 32) has a connecting portion 540, and is fixed to the armature 330 by laser welding or the like via the connecting portion 540 and is integrally formed. Further, in the structural portion 320, a yoke 322 (not shown) is coupled to the speaker housing 510 (the lower housing 312) via a second elastic member 344 such as a leaf spring.

[0075] Thus, the first aspect of the speaker 500 of the application example can be configured using the electromechanical transducer 300 of the third embodiment. Note that by appropriately designing the first elastic member 342 (the damper 520), the second elastic member 344 can be omitted. Alternatively, if the second elastic member 344 is appropriately designed, the damper 520 does not have to function as the first elastic member 342.

[0076] 〔Second Aspect〕 In FIG. 14(C): In the second aspect, the speaker housing 510 is a structure corresponding to the upper housing 310 (the first structural member), the damper 520 is a structure corresponding to the first elastic member 342, the diaphragm 530 is a structure corresponding to the lower housing 312, and the speaker housing 510 and the structural portion 320 are fixed. Therefore, in the electromechanical transducer 300 as a vibrator, the structural portion 320 vibrates with respect to the speaker housing 510 (the first structural member), so that the diaphragm 530 (the lower housing 312) can be vibrated.

[0077] Here, the diaphragm 530 (the lower housing 312) has a connecting portion 540, and is fixed to the armature 330 by an adhesive or the like via the connecting portion 540 and is integrally formed. In this case, the connecting portion 540 is preferably made of a relatively lightweight material because it functions integrally with the diaphragm 530. Further, in the structural portion 320, a yoke 322 (not shown) is coupled to the diaphragm 530 (the lower housing 312) via a second elastic member 344 such as a leaf spring.

[0078] Thus, the second aspect of the speaker 500 of the application example can be configured using the electromechanical transducer 300 of the third embodiment. Similar to the first aspect, by appropriately designing the first elastic member 342 (damper 520), the second elastic member 344 can be omitted. Alternatively, if the second elastic member 344 is appropriately designed, the damper 520 does not have to function as the first elastic member 342.

[0079] The present invention can be variously modified and implemented without being limited to the above-described plurality of embodiments.

[0080] In each embodiment, the outer shape formed by the upper and lower housings 110, 112, etc. is a cubic shape or a rectangular parallelepiped shape, but the outer shape may be a cylindrical shape, or any shape such as an oval shape or a castanet shape. Further, as described above, the housings 110, 112, etc. do not have to be box-shaped. For example, a structure in which the housings 110, 112, etc. are in a rectangular frame shape (square shape) and are integrally formed with the armature 130, etc., and the structural portion 120 and the armature 130, etc. are arranged inside the housings 110, 112, etc. is also possible.

[0081] Also, in each embodiment, the electrical terminals 150, etc. are arranged, but a structure in which lead wires are drawn out to the outside without using the electrical terminals 150, etc. may also be used.

[0082] The leaf spring 140 cited in the first embodiment, the compression coil spring 240 cited in the second embodiment, and the first elastic member 342 and the second elastic member 344 cited in the third embodiment are merely examples. As long as they can function as elastic members having desired properties, the form of the spring or the like can be any form, and they may be substituted with elastic rubber, an air-filled bag body, a liquid-filled bag body, or the like.

[0083] Furthermore, there is no need to limit the arrangement, specific shape, dimensions, etc. of various element parts, and various modifications can be applied.

Description of Reference Numerals

[0084] 100, 200, 300 Electromechanical transducer 110, 112 Housing 120 Structural part 122 Yoke 124 Magnet 126 Side plate 128 Coil 130 Armature 140 Leaf spring 240 Compression coil spring

Claims

1. A structural part integrally composed of two pairs of magnets arranged opposite to each other, a pair of yokes for guiding magnetic flux generated by the magnets, and an air-core coil arranged in a space surrounded by the yokes, An armature part integrally composed of an armature arranged to penetrate the air-core coil in the space of the structural part and a housing interconnected with the armature, An elastic member that allows relative vibration between the structural part and the armature part by being arranged between the housing and the structural part and being capable of applying an elastic restoring force to both, An electromechanical transducer comprising the same.

2. In the electromechanical transducer according to Claim 1, The elastic member, An electromechanical transducer characterized by being arranged in a space located in the relative vibration direction between the structural part and the housing.

3. In the electromechanical transducer according to Claim 1, The elastic member, An electromechanical transducer characterized by being arranged in each space located on both sides of the relative vibration direction between the structural part and the housing.

4. In the electromechanical transducer according to Claim 1 or 3, The elastic member, Is composed of a plurality of compression coil springs whose axes are arranged along the relative vibration direction between the structural part and the armature part, The structural part, Has a plurality of recesses capable of axially receiving each one end of the plurality of compression coil springs, The plurality of compression coil springs, An electromechanical transducer characterized in that each other end is arranged in contact with the housing while each one end is received in an individual one of the recesses.

5. In the electromechanical transducer according to Claim 4, The structural part, Includes side plates integrally connected to at least a pair of the yokes, and the recesses are formed in the side plates, which is an electromechanical transducer characterized by this.

Images