JP2006020179A - Acoustic transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acoustic transducer capable of realizing the cost reduction by improving an external connection terminal structure. <P>SOLUTION: A central hole 2a is formed to a frame 2 of a speaker 1 being a resin molded article having a square plane shape. Ribs 2b, which are a pair of integrally formed tubular parts with the same height, and dummy ribs 2c, which are a pair of integrally formed columnar parts with the same height as the tubular parts, are respectively formed at two corners of the four corners on the lower face side. A yoke 3 forming a magnetic circuit is fixed to the central hole 2a. A magnet 4 is fixed to the yoke 3. A top plate 5 is fixed to the magnet 4. A headed contact pin 8 as an external connection terminal is inserted to a stepped through-hole formed at the center of the rib 2b. A spring 9 energizes the tip part of the contact pin 8 so as to protrude it from the end face 2f of the rib 2b by being compressed by a circuit board 10 fixed to a recessed part 2d. The spring 9 is in contact with a wiring pattern to which a coil terminal 7a of the circuit board 10 is soldered. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an acoustic transducer, and more particularly to the structure of an external connection terminal thereof.

  In recent years, with the miniaturization of electronic devices, a technology for surface mounting electronic components on circuit boards has been developed and applied to various electronic components. In addition, there is a need for solderless soldering that provides electrical continuity without soldering as much as possible. A small speaker, which is an acoustic transducer used in a mobile phone or the like, is one such electronic component. Some of such conventional surface-mount acoustic transducers have various devices for the structure of external connection terminals (see, for example, Patent Document 1 and Patent Document 2). A small speaker as an example will be described with reference to the drawings. 5 is a plan view of a conventional small speaker, FIG. 6 is a cross-sectional view taken along the line BB of FIG. 5, and FIG. 7 is a bottom view.

  First, the configuration of this small speaker will be described. 5-7, 51 is a small speaker. Reference numeral 52 denotes an annular resin molded frame having a bifurcated portion 52a protruding at a part of the outer periphery. Reference numeral 53 denotes a plate-shaped yoke made of a magnetic material fixed to the central hole 52b of the frame 52. Reference numeral 54 denotes a disk-shaped permanent magnet fixed to the center of the bottom surface of the yoke 53 and having magnetic poles on the top and bottom. The yoke 53, the magnet 54, and the top plate 55 constitute a magnetic circuit portion, and the magnet 54 forms a magnetic circuit through a magnetic gap g that is a gap between the upper end portion of the yoke 53 and the peripheral portion of the top plate 55. Has been.

  Reference numeral 56 denotes a substantially spherical diaphragm integrally formed of a plastics material. The spherical surface has a constricted portion 56 a, and a flat peripheral portion 56 b is fixed to the upper end surface of the outer wall 52 c of the frame 52. Reference numeral 57 denotes a voice coil which is an annular air core coil formed by winding a winding made of enamel-coated copper wire, shaping it into a rectangular cross section and solidifying it with a paint, and is fixed below the constricted portion 56a of the diaphragm 56. Yes. The coil 57 is located at the center of the magnetic gap g.

  Reference numeral 58 denotes contact springs, which are arc-shaped leaf springs as a pair of external connection terminals, each being fixed to the frame 52 by heat caulking to two dowels 52b, and bent downward at an intermediate portion. A convex portion 58a is formed in the vicinity of the bifurcated tip portion of the contact spring 58, and the tip is warped upward. The winding terminal 57a of the voice coil 57 is led out to the lower surface side of the frame 52 from between the forked portions 52a, and the exposed end is soldered to the contact spring 58. Reference numeral 60 denotes an adhesive for protecting the soldered portion. Reference numeral 61 denotes a protector that has a top plate having a mesh-like sound emitting hole and protects the diaphragm 56.

When the speaker 51 is mounted on the circuit board of the electronic device, the contact spring 58 is compressed, and the lower end of the convex portion 58a is brought into contact with the wiring pattern of the circuit board so as to be conductive. An opening is formed on the outer periphery of the protector 61 and engages with a convex portion on the outer periphery of the frame 52. When an audio signal is input to the voice coil 57 of the speaker 51 through the contact spring 58, an electromagnetic force acts on the voice coil 57 in the magnetic circuit according to Fleming's left-hand rule, and the diaphragm 56 vibrates up and down to produce sound. To emit.
JP 2001-309487 A (FIG. 1, FIG. 2, paragraph numbers 0016 to 0017) Japanese Patent Application No. 2003-052777 (unpublished) (FIG. 3, paragraph numbers 0015 to 0016)

  However, in the conventional structure of such external connection terminals, generally, insert molding is performed on the frame side, or a plate spring is soldered to the inserted metal portion and joined by welding or the like. There is also a method of fixing to the resin frame with heat caulking. In the method using the insert, the cost of the frame itself is increased when the metal is inserted. Further, in a structure using a leaf spring as a contact spring, the leaf spring itself needs to be pressed, so the cost is slightly higher than that of a coil spring. When the frame is formed of an aggregate, it is very difficult to insert-mold the contact spring.

  The present invention has been made to solve such a conventional problem, and an object thereof is to provide an acoustic transducer capable of reducing the cost by improving the external connection terminal structure.

  In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention comprises a diaphragm having a voice coil fixed thereto, a yoke, a magnet fixed to the yoke, and a top plate fixed to the magnet. In the acoustic transducer having an external connection terminal in which the magnetic circuit portion is fixed to the frame and the coil terminal of the voice coil is connected to the frame, stepped through holes are respectively formed at two adjacent corners of the frame. In the stepped through hole, a headed contact pin as the external connection terminal and a spring for biasing the tip of the contact pin so as to protrude from the lower end surface of the stepped through hole are inserted, A circuit board having a wiring pattern facing the upper end surface of the stepped through hole is disposed so as to press the end of the spring, and the coil terminal of the voice coil is connected to the wiring Wherein the connected turn is electrically connected to the contact pin with the head through the spring.

  According to a second aspect of the present invention, in the first aspect of the invention, a pair of cylindrical portions through which the stepped through holes pass are formed at two corners of the lower surface of the frame, and the other two corners are formed. A pair of columnar parts having the same height as the cylindrical part is integrally formed.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the circuit board is disposed in a recess formed on the upper surface of the frame, and through holes are formed on both sides of the circuit board. The coil terminal is connected to one of the wiring patterns disposed through the wiring pattern.

  According to the present invention, a magnetic circuit unit including a diaphragm having a voice coil fixed thereto, a yoke, a magnet fixed to the yoke, and a top plate fixed to the magnet is fixed to the frame, and the voice is attached to the frame. In an acoustic transducer having an external connection terminal to which a coil terminal of a coil is connected, a stepped through hole is formed in each of two adjacent corners of the frame, and a head as the external connection terminal is formed in the stepped through hole. A circuit board having a wiring pattern in which a contact pin and a spring for biasing the tip of the contact pin so as to protrude from the lower end surface of the stepped through hole are inserted, and the wiring pattern faces the upper end surface of the stepped through hole Is arranged so as to press the end of the spring, and a coil terminal of the voice coil is connected to the wiring pattern and is connected to the wiring pattern via the spring. Since conducting the biasing contact pin, reduces the component cost and assembly cost, it was possible to reduce the cost of the acoustic transducer. In addition, a pair of cylindrical portions through which the stepped through hole passes are integrally formed at two corners of the lower surface of the frame, and a pair of columnar portions having the same height as the cylindrical portion are integrally formed at the other two corners. In the case where the acoustic transducer is incorporated into the mother board, the height of the speaker can be easily set by the cylindrical portion and the columnar portion.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings. 1 is a plan view showing a small speaker according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 3 is a partially enlarged cross-sectional view of FIG. FIG. 4 is a bottom view.

  First, the structure of the small speaker which is embodiment of this invention is demonstrated. 1 and 2, reference numeral 1 denotes a surface mount type small speaker, and 2 denotes a frame of the speaker 1 which is a resin molded product having a square planar shape. A central hole 2 a is formed at the center of the frame 2, and the upper peripheral edge of the central hole 2 a is a flat surface that sinks from the upper end of the frame 2. An air escape hole 2h is formed on the outer periphery, and a step 2g is formed on the outer side. At the four corners on the lower surface side of the frame 2, a pair of integrally formed ribs 2b, which are cylindrical portions, and dummy ribs 2c, which are columnar portions, are formed, and concave portions 2d are formed on the upper surface on the rib 2b side. Has been.

  Reference numeral 3 denotes a yoke forming a magnetic circuit fixed to the central hole 2a. Reference numeral 4 denotes a permanent magnet fixed to the center of the inner surface of the yoke 3, and reference numeral 5 denotes a top plate fixed to the magnet 4 with its center aligned. Reference numeral 6 denotes a diaphragm having a peripheral edge portion fixed to the step portion 2g. A voice coil 7 is an air-core coil and is fixed to the lower surface of the diaphragm 6.

  In FIG. 3, reference numeral 8 denotes a contact pin with a head 8 a as an external connection terminal, which is inserted into a stepped through hole 2 e formed at the center of the rib 2 b of the frame 2. A spring 9 is a compression coil spring, and is inserted into the through hole 2e. Reference numeral 10 denotes a circuit board fixed to the recess 2d, and a conductive wiring pattern 10a is formed through the through hole 10b. The spring 9 is compressed from the end portion 9a by the circuit board 10 and biases the tip end portion 8b of the contact pin 8 so as to protrude from the end face 2f of the rib 2b. The contact pins 8 and the springs 9 are plated with gold to prevent oxidation and corrosion, and are in contact with the wiring pattern of the circuit board 10 and are conductive.

  When assembling the contact pin 8, the contact pin 8 is first inserted into the stepped through hole 2e of the frame 2 in which the magnetic circuit portion and the diaphragm 6 have already been incorporated, and then the spring 9 is inserted. Cover the circuit board 10 and screw it. The circuit board 10 may be bonded by attaching a double-sided PSA sheet or applying an adhesive. Reference numeral 11 denotes a protector having a plurality of sound emitting holes 11a and a cylindrical portion engaged with the stepped portion 2g of the frame 2 on the lower surface. At one corner of the protector 11, a mark 11b for determining the position of the speaker 1 from above is provided.

  When the speaker 1 is assembled to a mother board such as a mobile phone, the rib 2b and the dummy rib 2c of the frame 2 are fixed by a pressing member attached to the mother board so as to contact the mother board. At this time, the rib 2b is brought into contact with the wiring pattern of the mother board with the help of the mark 11b. Thereby, the contact pin 8 biased by the spring 9 serves as a probe pin, and the wiring of the mother board and the coil terminal 7a of the speaker are connected.

  Next, the effect of this embodiment will be described. The contact pins 8 and the springs 9 constituting the external connection terminals can be formed by a processing method that does not require much component cost. In addition, since the assembly is not simply performed by inserting the stepped through hole 2e, it contributes to the cost reduction of the speaker 1. Further, when the speaker 1 is incorporated into the mother board, the height of the speaker 1 can be easily set by appropriately setting the height of the rib 2b and the dummy rib 2c. At this time, a desired spring thickness can be obtained simply by changing the spring 9. When the heights of the ribs 2b and the dummy ribs 2c can be set high, components can be disposed on the mother board under the frame 2.

  Further, since the frame 2 has a substantially cubic shape, the contact pin 8 and the circuit board 10 can be disposed at the corner portion where the diaphragm 6 has escaped, and the speaker 1 can be made thin. Furthermore, since no stress is applied to the acoustic part, stable acoustic characteristics can be obtained. In addition, it is not necessary to work to prevent rotation when assembling into equipment.

  Since the ribs 2b and the dummy ribs 2c having the same height are provided on the frame 2, it is possible to prevent the speaker 1 from being inclined when the frame 2 is incorporated in a device. The ribs 2b and the dummy ribs 2c may be prismatic shapes instead of cylindrical shapes. The fact that the soldering operation can be omitted in the conduction between the coil terminal 7a and the contact pin 8 can also answer the requirement of solderless when the speaker 1 is incorporated into the mother board. Moreover, since the contact pin 8 is excellent in impact resistance, the reliability of conduction is improved.

  Note that both the rib 2b and the dummy rib 2c can be omitted from the speaker 1. Further, the rib 2b may be provided and the dummy rib 2c may not be provided. By providing a cushion between the mother board and the frame 2 or the dummy rib 2c, chattering noise of the speaker 1 can be prevented. In addition, since the determination mark 11b is provided on the protector 11 that is the upper surface of the speaker 1, it is possible to prevent a difference in position when the speaker 11 is assembled on the motherboard. The shape, installation position, and number of marks 11b can be arbitrarily set.

  It is applied to acoustic devices such as a dynamic speaker and a receiver having a function of transmitting a key confirmation sound, a ringing melody sound, and a voice signal on a mobile phone.

It is a top view of the small speaker which is embodiment of this invention. It is sectional drawing which shows the AA arrow cross section of FIG. FIG. 3 is a partially enlarged sectional view of FIG. 2. It is a bottom view of the small speaker which is embodiment of this invention. It is a top view of the conventional small speaker. It is sectional drawing which shows the BB arrow cross section of FIG. It is a bottom view of the conventional small speaker.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Speaker 2 Frame 2b Rib 2c Dummy rib 2d Concave 2e Stepped through-hole 2f Lower end surface 3 York 4 Magnet 5 Top plate 6 Diaphragm 7 Voice coil 7a Coil terminal 8 Contact pin 8b Tip 9 Spring 9a End 10 Circuit board 10b Through Hall 10a wiring pattern

Claims (3)

  A magnetic circuit unit comprising a diaphragm having a voice coil fixed thereto, a yoke, a magnet fixed to the yoke, and a top plate fixed to the magnet is fixed to the frame, and a coil terminal of the voice coil is connected to the frame. In the acoustic transducer having an external connection terminal, stepped through holes are formed in two adjacent corners of the frame, and a headed contact pin as the external connection terminal and the contact pin are provided in the stepped through hole. And a circuit board having a wiring pattern facing the upper end surface of the stepped through hole is inserted into the spring end portion of the stepped through hole. The coil end of the voice coil is connected to the wiring pattern and led to the headed contact pin via the spring. Acoustic transducer, characterized in that it is.   A pair of cylindrical portions through which the stepped through holes pass are formed at two corners of the lower surface of the frame, and a pair of columnar portions having the same height as the cylindrical portion are integrally formed at the other two corners. The acoustic transducer according to claim 1, wherein: The circuit board is disposed in a recess formed on the upper surface of the frame, and the coil terminal is connected to one of wiring patterns disposed on both surfaces of the circuit board via through holes. The acoustic transducer according to claim 1 or 2.

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