JP2009088913A - Noise filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise filter that is provided with a wiring connection structure in which the contact resistance of a connection terminal is small and which is excellent in a vibration resistance property and sealing performance and can improve a heat radiation effect. <P>SOLUTION: In the noise filter in which a filter circuit 11 is resin-molded in a resin case 12, a nut member 14 is insert molded and embedded in an internal and external terminal connection part 13 of a resin case, a fixing bolt 20 inserted through inner side connection terminals 17 and 18 connected from an inner side of the resin case to a filter circuit side is screwed into the nut member, the inner side connection terminals are adhesively sandwiched between the head of the fixing bolt and the inner end face of the nut member, the fixing nut 21 is screwed into a point part of the fixing bolt projecting toward the external part of the resin case from the nut member by going through an outer side connection terminal 19 connected to an outer side circuit, and the outer side connection terminal is adhesively sandwiched between the fixing nut and the outer end face of the nut member to thereby make the inner side connection terminals conduct to the outer side connection terminal through the nut member. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a noise filter, and more particularly to a noise filter having an optimum structure for incorporation in an inverter device for controlling an electric motor used as a drive source of a vehicle.

  BACKGROUND ART A hybrid vehicle drive device includes an engine and a motor, an inverter device that controls the motor, and a DC power source that supplies power to the inverter device. In the inverter device, since electric noise generated when the switching element is operated may adversely affect the operation of other electric devices provided in the vehicle, the noise is removed by incorporating a noise filter. (For example, refer to Patent Document 1).

A general noise filter is in a state in which a filter circuit is resin-molded in a resin case, and wiring on the filter circuit side and external wiring are connected via a relay terminal. As the terminal structure, first nuts are screwed on both sides of a terminal bolt inserted into the board and fixed to the board, and crimp terminals are respectively sandwiched between first and second nuts inside and outside. A structure for fastening and fixing is known (for example, see Patent Document 2). A structure is also known in which a filter circuit side connection terminal and an external side connection terminal are overlapped on a nut embedded in the outer surface of the case and fastened with bolts (see, for example, Patent Document 3). . Furthermore, in order to discharge the residual voltage of the capacitor of the filter circuit of the noise filter, it is known to incorporate a discharge resistor (for example, refer to Patent Document 4).
JP 2002-2222917 A JP 2006-196419 A JP 2002-76255 A Japanese Patent Laid-Open No. 11-177369

  In the structure described in Patent Document 2, since the terminal bolt and each nut are separate members from the substrate, there is a problem in vibration resistance and airtightness, and the inner and outer terminals are connected via the terminal bolt. Because the terminal bolt must be made of brass with high conductivity, the nut tightening strength cannot be increased, and there is a problem with the contact resistance and vibration resistance of the connection terminal. It was. Furthermore, in the structure described in Patent Document 3, there is a problem in the sealing performance of the resin case because the connection terminal on the filter circuit side must be pulled out from the inside of the resin case. For this reason, there is a demand for higher performance wiring connection structures for devices mounted on automobiles that are subject to severe vibrations and exposed to harsh environments.

  The filter circuit of the noise filter has a built-in discharge resistor for discharging the residual voltage of the capacitor. However, when the noise filter is mounted on an automobile, the discharge resistor may break due to vibration or the like. .

  Accordingly, an object of the present invention is to provide a noise filter having a wiring connection structure in which the contact resistance of a connection terminal is small, excellent in vibration resistance and sealing properties, and improving the heat dissipation effect.

  In order to achieve the above object, a noise filter of the present invention is a noise filter in which a filter circuit is resin-molded in a resin case, and a nut member is insert-molded and embedded in an inner / outer terminal connection portion of the resin case. From the inner side, a fixing bolt inserted through the inner side connecting terminal connected to the filter circuit side is screwed into the nut member, and the inner side connecting terminal is interposed between the head of the fixing bolt and the inner end surface of the nut member. The fixing nut is inserted by inserting an external connection terminal connected to an external circuit to the tip of the fixing bolt protruding from the nut member to the outside of the resin case and screwing the fixing nut. The external connection terminal is sandwiched between the outer end surface of the nut member and the nut member.

  In particular, in the noise filter of the present invention, the internal connection terminal and the external connection terminal are electrically connected via the nut member, the fixing bolt is made of iron or steel, and the filter The circuit is characterized by having a plurality of discharge resistors connected in parallel.

  Furthermore, the present invention includes an inverter device incorporating the noise filter having the above-described configuration, and a hybrid vehicle incorporating this inverter device.

  According to the noise filter of the present invention, since the nut member is formed integrally with the resin case, the vibration resistance and the sealing performance can be improved. In addition, the sealing performance can be greatly improved by molding the inner connection terminal and the bolt head portion with resin, or by sealing in the resin case. Furthermore, by making the internal side connection terminal and the external side connection terminal conductive through the nut member, it is possible to improve the electrical conductivity as compared with the case of conducting through the bolt.

  Also, by using iron or steel (for example, stainless steel) for the fixing bolt and fixing nut, the tightening strength can be increased, the contact resistance of the connection terminal can be reduced, and the vibration resistance can be further increased. Can be improved. In addition, by connecting a plurality of discharge resistors in parallel to the filter circuit, the function can be maintained even if one discharge resistor breaks, and the vibration resistance of the noise filter can be improved.

  By incorporating the noise filter formed in this way into the inverter device, the stability of the inverter device can be achieved, and by incorporating the inverter device using such a noise filter into a hybrid vehicle, vibration, heat, etc. Reliable operation can be obtained in a stable state even when exposed to harsh environments.

  FIG. 1 is a cross-sectional view of a main part showing an embodiment of a noise filter of the present invention, FIG. 2 is a perspective view seen from the connection side of an external connection terminal, and FIG. 3 is a circuit diagram showing an example of a filter circuit.

  This noise filter is obtained by resin-molding a filter circuit 11 having a plurality of capacitors C1 to C4, coils L1 and L2, a plurality of discharge resistors R1 to R3 provided in parallel, and a ground terminal G in a resin case 12. The inner / outer terminal connection portion 13 has a pair of input terminals Pin and Nin and a pair of output terminals Pout and Nout.

  The inner / outer terminal connecting portion 13 is formed by insert-molding a hexagonal nut member 14 when the resin case 12 is injection-molded and embedded in a penetrating state, and the inner end surface 14a of the nut member 14 is the resin case 12. The outer end surface 14b of the nut member 14 is formed flush with the outer surface 12b of the resin case 12 and flush with the inner surface 12a. Further, the inner peripheral surface of the nut member 14 is provided with a female screw 15 only on the outer end side, and the outer peripheral surface is provided with a peripheral groove 16 for obtaining an anchor effect by entering resin.

  On the inner side of the resin case 12 of the inner / outer terminal connecting portion 13, a round crimp connected to the electrode plate 17 connected to the capacitor C 1 and the coils L 1 and L 2 as an inner side connecting terminal connected to the filter circuit 11 side. A terminal 18 is connected, and a round crimp terminal 19, which is an external connection terminal connected to the input side wiring or the output side wiring, is connected to the outside of the resin case 12 of the inner / outer terminal connection portion 13.

  The internal electrode plate 17 and the crimp terminal 18 are connected to the through holes of the electrode plate 17 and the crimp terminal 18 by inserting the fixing bolt 20 from the inside of the resin case 12, and the fixing bolt 20 is inserted into the nut member 14. And the male screw portion 20a on the front end side is screwed into the female screw 15 and tightened, and the electrode plate 17 and the crimp terminal 18 are sandwiched between the head 20b of the fixing bolt 20 and the inner end surface 14a of the nut member 14. It is done by wearing. At this time, since the female screw 15 is provided only on the outer end side of the nut member 14, the male screw portion 20a and the female screw 15 can be easily screwed together.

  On the other hand, the crimp terminal 19 on the outer side is inserted through the through hole 19a of the crimp terminal 19 into the male screw portion 20a on the tip side of the fixing bolt 20 protruding from the outer end surface 14b of the nut member 14 to the outside of the resin case 12. The fixing nut 21 is screwed onto the male screw portion 20 a and tightened, and the crimp terminal 19 is sandwiched between the fixing nut 21 and the outer end surface 14 b of the nut member 14.

  In this way, the inner electrode plate 17 and the crimp terminal 18 and the outer crimp terminal 19 are fastened with the fixing bolt 20 and the fixing nut 21 on both end faces of the nut member 14 that is insert-molded in the resin case 12 in a penetrating manner. By attaching and fixing, the electrode plate 17 and the crimp terminal 18 and the crimp terminal 19 are brought into a conductive state mainly through the nut member 14. Therefore, by using high-conductivity brass or copper for the nut member 14 to ensure continuity, the fixing bolt 20 and the fixing nut 21 do not require high continuity as in the prior art. 20 and the fixing nut 21 can be made of iron that can increase the tightening strength or steel such as stainless steel.

  Since the fixing bolt 20 and the fixing nut 21 are made of iron or steel, the electrode plate 17, the crimp terminal 18 and the crimp terminal 19 can be firmly fastened and fixed to the both end faces 14 a and 14 b of the nut member 14. The contact resistance can be greatly reduced and the vibration resistance can be greatly improved. Further, by molding the inside of the resin case 12 with the resin 12c or sealing it with a lid, the inner side electrode plate 17 and the crimp terminal 18 are not exposed to the outside, and these need to be pulled out to the outside. Therefore, the resin case 12 can be sufficiently sealed.

  Furthermore, since the cross-sectional area of the nut member 14 can be made larger than that of the conventional terminal bolt, not only the conductivity but also the heat dissipation is improved, so that the temperature rise of the filter circuit 11 can be suppressed. Moreover, since the resin thickness of the inner / outer terminal connection portion 13 can be increased as compared with the conventional terminal plate, the strength of the resin case 12 can be increased, and the vibration resistance of the noise filter can be improved.

  By incorporating the noise filter formed in this way into the inverter device, noise generated from the switching element of the inverter device can be effectively removed. Furthermore, such an inverter device can be expected to operate stably even when used in a hybrid vehicle with severe use environments such as vibration and heat. A hybrid vehicle incorporating such an inverter device is Control can be performed reliably in a stable state, the running performance can be improved, and various electric devices can also obtain a stable operating state.

  In addition, since a plurality of discharge resistors R1 to R3 are provided in parallel in the filter circuit 11, even if one discharge resistor breaks due to vibration or the like, the function of discharging the residual voltage of the capacitor can be maintained, and the leakage of the residual voltage can be maintained. Therefore, the vibration resistance of the noise filter can be improved.

It is sectional drawing of the principal part which shows the example of 1 form of the noise filter of this invention. It is the perspective view of the noise filter seen from the connection side of the external side connection terminal. It is a circuit diagram which shows an example of a filter circuit.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Filter circuit, 12 ... Resin case, 12a ... Inner surface, 12b ... Outer surface, 12c ... Resin, 13 ... Inner / outer terminal connection part, 14 ... Nut member, 14a ... Inner end surface, 14b ... Outer end surface, 15 ... Female screw, 16 ... Circumferential groove, 17 ... electrode plate, 18, 19 ... crimp terminal, 19a ... through hole, 20 ... fixing bolt, 20a ... male screw part, 20b ... head, 21 ... fixing nut

Claims (6)

  In a noise filter in which a filter circuit is molded in a resin case, a nut member is insert-molded and embedded in an inner / outer terminal connection portion of the resin case, and an internal connection connected from the inner side of the resin case to the filter circuit side A fixing bolt through which a terminal is inserted is screwed into the nut member, and the inner side connection terminal is sandwiched between the head of the fixing bolt and the inner end surface of the nut member, and from the nut member to the outer side of the resin case An external connection terminal connected to an external circuit is inserted into the tip of the fixing bolt protruding to the outside, and a fixing nut is screwed into the external connection between the fixing nut and the outer end surface of the nut member. A noise filter characterized by sandwiching terminals.   The noise filter according to claim 1, wherein the internal side connection terminal and the external side connection terminal are electrically connected via the nut member.   The noise filter according to claim 1, wherein the fixing bolt is made of iron or steel.   The noise filter according to claim 1, wherein the filter circuit includes a plurality of discharge resistors connected in parallel.   An inverter device comprising the noise filter according to any one of claims 1 to 4.   A hybrid vehicle incorporating the inverter device according to claim 5.

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