JP4453877B2 - Speaker - Google Patents

Description

  The present invention relates to a loudspeaker that is coupled to a magnetic circuit and has a frame in which a damper is attached and a passage that communicates the space between the magnetic circuit and the damper with the outside.

  Conventionally, in a loudspeaker that emits sound by vibrating a diaphragm by the electromagnetic action of a magnetic circuit and a voice coil, in order to prevent the magnetic circuit from becoming hot due to the magnetic action with the voice coil, It has been proposed to form a vent (for example, Patent Document 1). Specifically, a vent hole (passage) is formed in a frame that is coupled to the magnetic circuit and communicates the space between the magnetic circuit and the damper and the outside. The magnetic circuit can be cooled by the air flowing through the ventilation hole, and the temperature rise of the magnetic circuit can be suppressed.

  In addition, since air can enter and exit between the space between the magnetic circuit and the damper and the outside through the vent hole, the pressure in the space between the damper and the magnetic circuit can be lowered. Accordingly, it is possible to effectively prevent the operation of the damper from being hindered due to an increase in the pressure in the space.

  However, if vents are formed in the frame, there is a risk that fine dust may enter the space between the magnetic circuit and the damper through the vents, and if such fine dust enters, the function of the speaker may be impaired. Become. In particular, in a vehicle-mounted speaker built in a vehicle door or the like, iron powder may enter through a vent hole. It is particularly a problem that such iron powder enters a speaker in which magnetic flux is formed by a magnetic circuit.

In view of this, it has been proposed to shield the passage from the opening of the vent hole to the magnetic gap in the space between the magnetic circuit and the damper with a shielding member (see, for example, Patent Document 2). By providing the shielding member in this manner, it is possible to prevent fine dust and iron powder from entering the magnetic gap and to prevent the function of the speaker from being impaired.
Japanese Utility Model Publication No. 1-77092 JP 2002-218588 A

  However, when the shielding member is provided in the speaker as described above, there arises a new problem that the acoustic characteristics of the speaker may be impaired by the shielding member, and the structure of the speaker becomes complicated.

  The present invention pays particular attention to magnetic material powder such as iron powder, and it is easy for the magnetic material powder to enter the space between the magnetic circuit and the damper through the passage formed in the frame without impairing the acoustic characteristics of the speaker. A speaker that can be prevented with a simple structure is provided.

  A speaker according to the present invention is a speaker in which a passage is formed in a frame that is coupled to a magnetic circuit and communicates between a space between the magnetic circuit and the damper and the outside in a frame to which the damper is attached. In this configuration, a recess is formed so as to open to the inside and to pass a magnetic flux generated by the magnetic circuit.

  With such a configuration, even if magnetic material powder enters the passage formed in the frame from the outside, the magnetic material powder is attracted by the magnetic flux passing through the recess opening inward of the passage and is captured by the recess. Be able to. As a result, it is possible to prevent the magnetic material powder from entering the space between the magnetic circuit and the damper through the passage.

  In the speaker according to the present invention, the frame is joined to a top plate included in the magnetic circuit, at least a part of the passage is formed on a joint surface of the frame with the top plate, and the recess is The top plate may be formed on the joint surface with the frame so as to open to the inside of the passage.

  With such a configuration, since a recess is formed in the top plate that is a part of the magnetic circuit, the magnetic flux generated in the magnetic circuit can be easily passed through the recess.

  Furthermore, in the speaker according to the present invention, each joint surface between the top plate and the frame can be inclined with respect to the radial direction of the speaker.

  With such a configuration, the magnetic flux generated on the top plate of the magnetic circuit is likely to be saturated at the joint surface with the inclined frame, and the magnetic flux can be passed through the recess formed on the joint surface with higher density. It becomes like this.

  Further, in the speaker according to the present invention, the frame is made of a magnetic material, and a joint surface of the frame with the top plate has an overhanging portion that projects into the recess formed in the top plate. Can do.

  With such a configuration, the frame bonded to the top plate that is a part of the magnetic circuit is formed of a magnetic material, and the frame can also function as a part of the magnetic circuit. Thereby, magnetic flux concentrates on the projecting portion of the frame projecting on the recess, and the magnetic material powder can be reliably captured by the recess.

  According to the speaker of the present invention, the magnetic substance powder that has entered the passage formed in the frame using the magnetic circuit for exerting the original function of the speaker is provided in the recess without particularly providing other members in the speaker. The magnetic material powder can be prevented from entering the space between the magnetic circuit and the damper through the passage formed in the frame with a simple structure without impairing the acoustic characteristics of the speaker. Will be able to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A speaker according to an embodiment of the present invention is configured as shown in FIG.

  In FIG. 1, the speaker includes a yoke 10, a ring-shaped magnet 30, and a ring-shaped top plate 21. The yoke 10 has a structure in which a columnar protrusion 12 is formed at the center of a disk-shaped bottom 11. A magnet 20 is fixed to the bottom 11 of the yoke 10 so as to surround the protruding portion 12, and a top plate 21 is fixed on the magnet 20 so as to surround the protruding portion 12 of the yoke 10. The yoke 10, the magnet 20 and the top plate 21 constitute a magnetic circuit. A horn-shaped frame 50 protruding forward is fixed on the top plate 21.

  The frame 50 includes an attachment bottom 51, a cylindrical portion 52 formed so as to stand on the outer peripheral portion of the attachment bottom 51, and a horn that extends forward from the end of the cylindrical portion 52 and gradually spreads forward. It is comprised from the part 53 and the flange part 54 formed in the outer periphery of the horn part 53. FIG. The frame 50 is fixed on the top plate 21 such that the attachment bottom 51 is joined to the top plate 21.

  The speaker further includes a diaphragm 30 having a substantially conical shape and a voice coil unit 40 having a structure in which a voice coil 41 is wound around one end of a bobbin 42. The other end of the bobbin 42 has a diameter of the diaphragm 30 so that the voice coil 41 is disposed in a magnetic gap G formed between the outer peripheral surface of the protruding portion 12 of the yoke 10 and the inner peripheral surface of the top plate 21. It is fixed to the inner part in the direction. Also, the radially inner portion of the ring-shaped support member 31 made of an elastic member and the radially outer portion of the diaphragm 30 are bonded and fixed, and the radially outer portion of the support member 31 is further attached to the flange portion 54 of the frame 50. Bonded and fixed. That is, the radially outer portion of the diaphragm 30 is supported by the support member 31 whose radial outer portion is bonded and fixed to the flange portion 54 of the frame 50 so as to vibrate in the front-rear direction.

  Further, the outer peripheral edge of the damper 32 formed in a ring shape with a synthetic resin or cloth is fixed to a step portion formed at the boundary portion between the cylindrical portion 52 and the horn portion 53 of the frame 50, and its inner periphery The part is fixed to a predetermined part of the bobbin 42. Undesired vibration in the radial direction of the diaphragm 10 is regulated by the damper 32. Note that a bowl-shaped dust cap 33 is provided on the diaphragm 30 so as to cover the bobbin 42.

  A plurality of (for example, the space between the magnetic circuit (the yoke 10, the magnet 20, and the top plate 21) and the damper 32 and the outside communicate with each other at the boundary portion between the mounting bottom portion 51 and the cylindrical portion 52 of the frame 50. 5 passages 60 are formed at predetermined angular intervals. The top plate 21 is formed with a notch recess 21 a that opens inward of each passage 60. The detailed structure of each passage 60 is shown in FIG. FIG. 2 is a cross-sectional view showing a part A in FIG. 1 in detail.

  In FIG. 2, an inclined surface 21b that is inclined with respect to the radial direction (left-right direction in the drawing) is formed at the outer peripheral portion of the top plate 21, and the surface of the top plate 21 including the inclined surface 21b The attachment bottom 51 is joined. A hole 55 penetrating from the surface opposite to the joint surface with the top plate 21 toward the joint surface is formed at a boundary portion between the attachment bottom portion 51 of the frame 50 and the cylindrical portion 52, and the top plate 21. A groove 56 that opens toward the top plate 21 is formed on the joint surface with the outer peripheral surface of the cylindrical portion 52 so as to continue from the hole 55. When the attachment bottom 51 of the frame 50 is joined to the top plate 21, the open surface of the groove 56 is covered. The covered groove 56 and the subsequent hole 55 form a passage 60 that communicates the space between the magnetic circuit and the damper 32 and the outside (the outside of the frame 50).

  When the inclined surface 21b of the top plate 21 facing the boundary portion between the groove 56 and the hole 55 in the passage 60 is cut out, a notch recess 21a that opens inward of the passage 60 is formed in the inclined surface 21b. . In addition, the joint surface of the mounting bottom 51 of the frame 50 with the inclined surface 21b of the top plate 21 has a protruding portion 51a protruding to the notch recess 21a (the hole 55 is formed so that the protruding portion 51a is formed). It is formed).

  In the speaker having the structure described above, a plurality of passages 60 that communicate the space between the magnetic circuit and the damper 32 and the outside are formed in the frame 50, so that the voice coil 41 is caused by the air flowing through each passage 60. The rise in temperature of the magnetic circuit that generates heat and the voice coil 41 itself is suppressed due to the electromagnetic action. Further, since air enters and exits between the space between the magnetic circuit and the damper 32 and the outside through each passage 60, the pressure in the space is lowered, and the operation of the damper 32 (vibration of the diaphragm 30) is hindered. Is prevented.

  In each passage 60 described above, a notch recess 21a is formed in the top plate 21 which is a part of the magnetic circuit, and a magnetic flux generated by the magnetic circuit passes through the notch recess 21a. For this reason, even if magnetic material powder F, such as iron powder, enters each passage 60 from the outside, the magnetic material powder F is collected and captured in the notch recess 21a by the magnetic flux. Therefore, the magnetic material powder F is prevented from entering the space between the magnetic circuit and the damper 32 and the magnetic gap G through the passages 60.

  In particular, when the frame 50 is formed of a magnetic material such as iron, the mounting bottom 51 that is joined to the top plate 21 also functions as a part of the magnetic circuit. In this case, since the projecting portion 51a is formed on the mounting bottom 51 so as to project to the notched recess 21a, the magnetic flux concentrates on the projecting portion 51a and the magnetic material powder F that has entered the passage 60 is more reliably notched. It can be collected and captured by 21a.

  Further, since the notched recess 21a is formed on the inclined surface 21b of the top plate 21, the magnetic flux generated on the top plate 21 is likely to be saturated on the inclined surface 21b, and a high-density magnetic flux is passed through the notched recess 21a. It becomes possible. As a result, the magnetic material powder F can be collected and captured in the notch 21a more reliably.

  In the above-described example, the notch recess 21a is individually formed for each of the passages 60 (grooves 56). However, the notch recess is formed by notching the inclined surface 21b of the top plate 21 in a ring shape. 21a may be formed.

  The frame 50 can also be formed of a synthetic resin or an aluminum alloy. However, the case where the magnetic material is used as described above is preferable in that the magnetic flux can be used effectively.

  As described above, the speaker according to the present invention has a simple structure that the magnetic material powder enters the space between the magnetic circuit and the damper through the passage formed in the frame without impairing the acoustic characteristics of the speaker. This is useful as a loudspeaker in which the frame is formed with a passage communicating the space between the magnetic circuit and the damper and the outside.

It is sectional drawing which shows the structure of the speaker which concerns on one Embodiment of this invention. It is a fragmentary sectional view which shows the A section in FIG. 1 in detail.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Yoke 11 Bottom part 12 Protrusion part 20 Magnet 21 Top plate 21a Inclined surface 21b Notch recessed part 30 Diaphragm 31 Support member 32 Damper 33 Dust cover 40 Voice coil unit 41 Voice coil 42 Bobbin 50 Frame 51 Mounting bottom part 51a Overhang part 52 Cylindrical shape Part 53 horn part 54 flange part 55 hole 56 groove 60 passage

Claims (4)

A speaker which is coupled to a magnetic circuit and has a frame in which a damper is attached and a passage communicating the space between the magnetic circuit and the damper and the outside is formed.
The speaker is characterized in that the passage has an inward opening and a recess formed to allow a magnetic flux generated in the magnetic circuit to pass therethrough. The frame is bonded to a top plate included in the magnetic circuit,
At least a part of the passage is formed on a joint surface of the frame with the top plate,
The speaker according to claim 1, wherein the recess is formed on a joint surface of the top plate with the frame so as to open inward of the passage.   3. The speaker according to claim 2, wherein each joint surface between the top plate and the frame is inclined with respect to a radial direction of the speaker. 4. The frame according to claim 2 or 3, wherein the frame is made of a magnetic material, and a joint surface of the frame with the top plate has an overhanging portion that projects into the recess formed in the top plate. Speaker.

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