JP2005101499A - Coil block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil block having an enough reluctance, a good direct-current superimposing characteristic, and a low price, wherein its respective inductors are suppressed from coupling mutually, with respect to the coil block storing the two inductors therein dealing with the increasing number of channels. <P>SOLUTION: With respect to the coil block integrating thereinto a plurality of inductors used in a digital amplifier circuit, the plurality of inductors have a ring core and two coils each of which has an insulating-coating-lead type wiring wound around a rod-form core, and the ring core is inserted into a metal case from its opening portion, and further, the plurality of coils are so stored in the ring core by stacking them vertically as to oppose both the end surfaces of each rod-form core to the inner wall surface of the ring core. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention mainly relates to an inductor used in a digital amplifier circuit for a speaker.

FIG. 6 is a circuit schematic diagram of one channel of the speaker digital amplifier circuit.
6A is a schematic circuit diagram according to a SEPP (Single Ended Push Pull) system, and FIG. 6B is a schematic circuit diagram according to a BTL (Balanced Transformer Less) system.
In the figure, IC is an integrated circuit for PWM modulation, AMP is a digital amplifier, L and C are inductors and capacitors constituting a low-pass filter LPF, and SP is a speaker. As described above, the SEPP circuit method requires one set of LPFs for one channel, and the BTL circuit method requires two sets of LPFs for one channel.

In recent years, in digital amplifiers, the surround function with a sense of reality close to that of movie theaters has attracted attention and has become multi-channel. In this surround function, the BTL circuit system of FIG. 6B has become mainstream, and two sets of LPFs with one channel are required. Generally, 4 to 8 channels are used, and 8 to 16 inductors having a large shape (approximately 4 mm in outer diameter and 6 mm in height) are used. As described above, since the number of inductors connected to each speaker is increased due to the increase in the number of channels, and the area occupied by the inductor substrate increases, a product in which two inductors are integrated is required. It became so.

  FIG. 7 shows a coil block in which two commercialized inductors are integrated. In this coil block 10, three drum cores 11 are provided with windings 12 and 13 forming two inductors and covered with a pot core 14. In order to reduce the coupling between the winding 12 and the winding 13, the gap G1 between the outer peripheral surface of the drum core 11 and the inner peripheral surface of the pot core 14 and the gap Gs between the upper upper surface of the drum core 11 and the ceiling surface of the pot core 14 are set. In order to improve the direct current superimposition characteristic, it is necessary to provide gaps G1 and Gs that are magnetoresistive large. In addition, a resin spacer S is provided for the purpose of suppressing variations in the gap Gs between the upper surface of the drum core 11 and the ceiling surface of the pot core 14. However, when the insertion pressure at the time of assembly is insufficient, the gap Gs increases. In order to suppress the variation, a step of inserting and fixing (depending on the time of bonding) the bottom surface of the drum core 11 provided with the winding in the pot core 14 is required, and the work process and work man-hour are increased.

As described above, when the total gap Go (= G1 + Gs) is minimized and the coupling between the windings is reduced, the DC superposition characteristic is deteriorated.
If the total gap Go is increased by taking into account the DC superimposition characteristics, the magnetic fluxes of the winding 12 and the winding 13 are leaked and coupled, so that there is a problem that a predetermined inductance cannot be obtained. Therefore, it cannot be said that the inductor sufficiently corresponds to the characteristics required for the choke coil for digital amplifier.
Therefore, FIG. 8 shows a coil block in which two windings are eliminated and two inductors are integrated. The coil block 20 has a structure in which two inductors each including a spacer S sandwiched between the upper surface of the convex portion of the T-shaped core 21 and the ceiling of the pot core 24 are provided in a resin case 25. Vertically stacked and stored. However, the price is higher than when two inductors are used discretely.
JP 2003-151832 A

  In view of the conventional drawbacks as described above, the present invention is suitable for multi-channel, and in a coil block that accommodates two inductors, the mutual coupling in each inductor is suppressed, and a sufficient magnetic resistance is provided with a DC superposition characteristic. An object is to provide a good and inexpensive coil block.

In order to achieve the above object, the present invention provides a coil block including a plurality of inductors used in a digital amplifier circuit, wherein the plurality of inductors include a ring core and a coil in which a rod-shaped core is wound with an insulating film conductor. The ring core is inserted through the opening of the metal case, and a plurality of coils are vertically stacked and stored so that both end faces of the rod-shaped core and the inner wall surface of the ring core face each other in the ring core. Further, it is characterized in that it is housed in a metal case having an opening on the bottom surface, or a pot core is used instead of a ring core.
A substrate for holding winding terminals of a plurality of coils is attached to the bottom surface of the ring core or pot core.

The coil block of the present invention has a structure in which a plurality of rod-shaped cores wound with insulating coating conductors in a ring core or pot core are arranged vertically, and a gap formed between both end faces of the rod-shaped core and the inner periphery of the ring core. By providing a sufficient thickness, a large magnetic resistance can be created and the DC superposition characteristics can be improved. In addition, the magnetic flux generated from multiple coils takes a loop of magnetic flux that circulates around the ring core from both ends of each rod-like core, so that the coupling between the windings can be reduced as much as possible, and the mutual inductance is stable. ing.
In this way, it is possible to provide an inexpensive coil block with good direct current superposition characteristics that suppresses mutual coupling in each coil and has sufficient magnetic resistance.

  In order to provide a low-cost coil block with good DC superimposition characteristics, which has a sufficient magnetic resistance, in a coil block that accommodates multiple channels and suppresses mutual coupling in each inductor. The inductor includes a ring core or pot core, and a plurality of coils in which a rod-shaped core is wound with an insulating film conductor, and a plurality of coils are arranged so that both end faces of the rod-shaped core and the inner surface of the ring core or pot core face each other in the ring core or pot core. Are formed by vertically stacking and storing.

  Hereinafter, a coil block according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 shows an assembled perspective view for explanation in which two inductors according to the first embodiment of the present invention are integrated.
In FIG. 1, 1 is a metal case having an opening on the bottom surface, 2 is a ring core, 3a and 3b are coils, 4 is a round bar core forming a coil, 5 is a winding forming a coil, and 7 is a winding. It is the structure of the board | substrate holding a terminal.

  The ring core 2 and the round bar-shaped core 4 are formed by firing a ferrite magnetic body. The coils 3a and 3b are obtained by winding a predetermined number of turns using an insulating film conductor obtained by applying an insulating film treatment to the round bar-shaped core 4. The coils 3a and 3b may be formed by inserting a previously wound air-core spring coil into the round bar core 4.

The substrate 7 is provided with a hole for taking out and holding a terminal for external connection on an insulating and heat resistant resin thin plate, and holds the winding terminals of the coils 3a and 3b through holes in predetermined positions. And external connection terminals. And the coil | winding terminal which came out through the hole of the board | substrate 7 removes an insulating film with immersion solder etc., and is set as the terminal for external connection.
In addition, you may remove an insulating film previously by immersion solder etc. in the state of the coils 3a and 3b or the state of a spring coil.
Moreover, in order to hold | maintain a coil | winding terminal, the board | substrate 7 may provide a land pattern around the hole of the board | substrate 7, or may provide a through hole, and may solder at the same time as removing an insulating film by immersion solder.

The metal case 1 has a ground terminal 1a for connecting to the ground of an external circuit extending on the bottom side. The coil block is assembled by inserting the ring core 2 through the opening on the bottom surface of the metal case 1, and storing the coils 3 a and 3 b on the substrate 7 in the ring core 2 with the core axes mounted in parallel. And the substrate 7 are fixed with an adhesive.
Alternatively, the coils 3 a and 3 b and the substrate 7 may be fixed by pouring a heat-resistant adhesive made of an insulating resin into the ring core 2. Furthermore, the metal case 1 and the ring core 2 may be fixed in advance using an adhesive.

FIG. 2 is a cross-sectional view for explaining the characteristics of the coil block according to the embodiment of the present invention. 2 (a) is a sectional view of the ring cores seen from the top, FIG. 2 (b) is a longitudinal sectional view of the ring core as viewed from the side.
As shown in FIG. 2 (a), the magnetic fluxes φa and φb of the coils 3a and 3b enter the ring core from one end face 4a (or 4b) of the round bar core 4 from the inner side of the ring core and pass through the ring core on the 2a side. As described above, from the other end face 4b (or 4a) of the round bar core 4, the magnetic flux loops φa1 and φb1 entering the round bar core 4 from the inner peripheral proximity portion of the ring core, and the one end face 4a (or 4b) of the round bar core 4. Magnetic flux loops φa1 and φb1 that enter the ring core from the inner proximity portion of the ring core, pass through the ring core on the 2b side, and enter the round bar core 4 from the other end surface 4b (or 4a) of the round bar core 4 and the inner peripheral proximity portion of the ring core. It becomes. The magnetic flux φa of the coil 3a is φa = φa1 + φa2, and the magnetic flux φb of the coil 3b is φb = φb1 + φb2. At this time, the positional relationship of the coil 3a (or 3b) in the ring core 2 is that the gap Ga between the one end face 4a of the coil and the inner peripheral face of the ring core, and the gap between the other end face 4b of the coil and the inner peripheral face of the ring core. Gb is a stable inductor because the total gap Go (= Ga + Gb), which is the sum of the left and right gap dimensions, is constant with respect to the deviation in the X-axis direction.

Further, since the coupling by the leakage magnetic flux of the coils 3a and 3b is concentrated on the ring core like the above-mentioned magnetic flux loops φa and φb, the upper and lower couplings are extremely small and no change in inductance is recognized.
This means that the coupling between the coils 3a and 3b is extremely small, and there is no change in inductance due to positional deviation in the X-axis direction, and the overall gap Go can be made large to improve the DC superposition characteristics and increase the positional accuracy in manufacturing. Therefore, a stable and inexpensive coil block without variations can be realized. Further, regarding the Y-axis direction, if the two coils are in the ring core, the inductor or the like is not affected.

Next, a second embodiment of the present invention will be described with reference to FIG. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
The coil block of the second embodiment shown in FIG. 3 is different from the first embodiment in that the substrate 7 is not used. That is, the coils 3a and 3b are mounted directly on the substrate of the external circuit with the core axes stacked in parallel, and then the ring core 2 and the metal case 1 are mounted to form a coil block. Thus, the coil block of the present invention can easily assemble individual components on a block substrate or the like.

  In addition, although the coils 3a and 3b are stacked in parallel with the core axis, when changing the connection position between the coil winding terminal and the external circuit, the coil positional relationship is rotated horizontally as shown in FIG. The line terminal position may be shifted. That is, FIG. 4 (a) is obtained by rotating the coil 3a by 45 ° with respect to the coil 3b, and FIG. 4 (b) is obtained by rotating the coil 3a by 90 ° with respect to the coil 3b. Thus, the positional relationship between the coil 3a and the coil 3b can be rotated horizontally to change the connection position with the external circuit.

FIG. 5 illustrates a third embodiment of the present invention. Note that the same components as those in the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted.
FIG. 5A is a longitudinal sectional view using a pot core. FIG. 5B is a bottom view using rounded square pot cores having different aspect ratios.
As shown in FIG. 5, the difference from the first and second embodiments is that a pot core 2p in which the upper surface of the ring core is closed instead of the ring core is used, and the number of parts is reduced by removing the metal case. Is a feature.

FIG. 5B shows that the mounting area is smaller than that of a round shape and a square shape by using two rounded square pot cores 2q with different aspect ratios by stacking two coils vertically in parallel with the winding axis. This is an example.
As described above, by using the pot core, the leakage magnetic flux generated from the coil can be reduced as compared with the ring core, and as a result, the performance of the device using this coil block can be improved. Furthermore, it is resistant to drop impact and can be obtained at low cost because it is easy to mold and process.
As a result, the product unit price can be reduced, and a coil block that is resistant to drop impact can be obtained.

As described above, the coil block of the present invention has a structure in which a plurality of coils are stacked in a ring core or a pot core and arranged vertically, and the total gap formed between both end faces of the rod-shaped core and the inner peripheral surface of the ring core or pot core. When sufficiently provided, a large magnetic resistance can be created and the DC superposition characteristics can be improved. Moreover, since the magnetic flux of each coil circulates through the ring core, the coupling between the coils can be made extremely small.
Also, in the coil block manufacturing method, since it can be easily assembled without increasing the positional accuracy in the X-axis direction, an inexpensive coil block with good workability can be realized. Furthermore, by covering the metal case and using the pot core, the leakage flux of the coil does not flow out to the outside and is not affected by the leakage flux from the outside.

  As mentioned above, although the Example of the coil block of this invention was described, it is not restricted to these Examples. For example, in the embodiment of the present invention, two coils are stacked and formed. However, the number of coils is not limited to two, and a plurality of coils may be stacked as necessary. In addition, the rod-shaped core has a round cross section, but if it is desired to reduce the height, it may be oval or flat and may have a shape suitable for the purpose. Furthermore, although the ring core, the pot core, and the metal case have been described in a round shape, they may be rectangular or polygonal to have a directional shape. Furthermore, it is only necessary to ensure insulation between the two coils. Instead of a gap, a resinous adhesive may be used, or a thin plate or the like may be used.

The assembly perspective view of the coil block which is 1st Example of this invention. It is a figure which shows the positional relationship of the coil of the coil block which is the 1st Example of this invention, and a ring core, sectional drawing (a) seen from the upper part, and longitudinal sectional drawing (b) seen from the side. The coil block which used the external circuit board in 2nd Example of this invention. Explanatory drawing which shows the positional relationship of the coil and ring core in the 1st coil block of this invention. The longitudinal cross-sectional view (b) and bottom view of a coil block which are the 3rd Example of this invention. The circuit schematic for digital amplifiers. A coil block using a conventional three-piece kite. Coil block using a conventional resin case.

Explanation of symbols

1 Metal Case 2 Ring Core 3a, 3b Coil 4 Rod Core 5 Winding 7 Substrate

Claims (4)

In a coil block containing multiple inductors used in a digital amplifier circuit,
The plurality of inductors include a ring core and a plurality of coils in which a rod-shaped core is wound with an insulating coating wire, and the plurality of coils are arranged in the ring core so that both end faces of the rod-shaped core and the inner wall surface of the ring core face each other. Coil block characterized by being stacked and stored vertically. The coil block according to claim 1, wherein
A metal case having an opening at the bottom, and the coil block inserted from the opening of the metal case. In a coil block containing multiple inductors used in a digital amplifier circuit,
The plurality of inductors includes a pot core and a plurality of coils in which a rod-shaped core is wound with an insulating coating wire, and the plurality of coils are arranged in the ring core so that both end surfaces of the rod-shaped core and the inner wall surface of the pot core face each other. Coil block characterized by being stacked and stored vertically. 4. The coil block according to claim 1, wherein a substrate for holding winding terminals of the plurality of coils is provided and attached to the bottom surface of the ring core. 5.

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