JP2005304162A - Electric connection box - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shield an operational sound of a switch or the like generated in a case by providing a sound absorbing material or a noise reducing material in the case of an electric connection box. <P>SOLUTION: In the electric connection box 10 containing an electric component such as a relay 14 in a case, a sound absorbing material, a sound absorbing body, a noise reducing material and/or a noise reducing body composed of foaming resin, foaming metal, a Helmholtz resonator or the like, is provided on the inner or outer surface of the case so that an operational sound generated when the relay 14 in the case is operated (on) or reset (off) is not leaked to the outside but shielded. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrical junction box, and more specifically, a sound absorbing and silencing mechanism is provided in a case to absorb and mute operating sounds of a relay switch and the like generated in the case.

2. Description of the Related Art Conventionally, an electrical junction box provided in a vehicle includes a laminated body in which a bus bar made of a conductive metal plate and an insulating plate are alternately laminated, and an in-vehicle power source (through a bus bar circuit configured by the laminated body ( For example, what connects a battery) to a large number of on-vehicle loads (electrical components) is generally known.
In many cases, the electrical junction box usually incorporates a mechanical relay that operates a contact plate in response to on / off of the switch, and mechanical noise is generated when switching on / off. It becomes one of. As a measure for quieting the passenger compartment, it is also considered to arrange the electrical junction box in the engine room etc. outside the passenger compartment, but if it is placed outside the passenger compartment it is necessary to have waterproof performance, which greatly increases the cost It becomes.

In addition, in the Japanese Patent Application Laid-Open No. 2001-319708 (Patent Document 1), the applicant of the present invention has provided an electric connection box provided with a semiconductor switching element instead of a mechanical relay in order to reduce the size and simplify the electric connection box. providing. When a semiconductor switching element is used, no mechanical noise is generated when the mechanical relay is turned on / off. However, if a semiconductor switching element is used instead of a mechanical relay, the semiconductor switching element is very expensive, and thus there is a problem that the cost of the electrical junction box is increased.
JP 2001-319708 A

  The present invention has been made in view of the above problems, and an object of the present invention is to add a sound absorption / silence function to the case of the electrical junction box so as to absorb and silence the operation sound of a switch and the like generated in the case.

  In order to solve the above problems, the present invention firstly attaches a sound absorbing material to an inner circuit or an outer surface of a case main body in which an internal circuit and an electronic component connected to the internal circuit are accommodated, or a cover that covers the case main body, The sound absorbing material is provided with an electrical junction box comprising a resin or metal foam material, a sound absorbing molded plate formed with a large number of irregularities, or a sound absorbing molded plate formed with a large number of cylindrical portions. Yes.

  According to the above configuration, since the operation sound generated by the electronic components in the cover is absorbed by the sound absorbing material attached to the case body or the cover, it is possible to prevent the operation sound from being heard outside the electrical junction box. it can. Thereby, even if the electrical junction box is mounted in the vehicle interior and the relay in the electrical junction box is a mechanical relay, the operation sound does not disturb the passengers in the vehicle interior.

  Foamed urethane or the like is used as the foamed resin, and foamed Celmet (manufactured by Sumitomo Electric Co., Ltd.) or the like is suitably used as the metal foamed material. When a metal foam material is attached to the outer surface of the case body or cover, a heat dissipation function can be provided.

  In addition, when the sound absorbing material is a sound absorbing molded plate formed with a large number of uneven portions or a sound absorbing molded plate formed with a large number of cylindrical portions, a Helmholtz resonator is formed by the sound absorbing molded plate and the case body or cover. Is formed, and the operation sound in the electric junction box can be effectively absorbed.

In addition, the present invention secondly provides a sound absorbing portion integrally formed on an inner wall or an outer wall of a case main body in which an internal circuit and electronic components connected to the internal circuit are accommodated or a cover that covers the case main body. The section provides an electrical junction box characterized by comprising a large number of uneven portions or a large number of cylindrical portions.
According to the above configuration, since the case main body or the cover itself covering the case main body has a sound absorbing function, it is not necessary to attach a sound absorbing material made of a separate material, and the number of steps for assembling the electrical junction box can be reduced. This eliminates the cost of parts.

The length and hole diameter of the cylindrical portion, the height and area of the concave and convex portions are formed corresponding to the generation frequency to be sound-absorbed, and a sound-absorbing material made of a foam material is disposed on the deepest surface of the cylindrical portion. Is preferred.
According to the above configuration, the cylindrical portion or uneven portion provided on the inner surface of the case plays a role as a Helmholtz resonator, and the length and hole diameter of the cylindrical portion, the height and area of the uneven portion are made to correspond to the generation frequency to be absorbed. Since it forms, the operation sound in an electrical junction box can be absorbed efficiently. In addition, since the sound absorbing material provided at the deepest part of the cylindrical portion absorbs the sound that cannot be absorbed by the Helmholtz resonator, the operating sound generated in the case can be reliably absorbed.

It is preferable that the arrangement position of the sound absorbing material or the sound absorbing molding plate attached to the case main body or the cover includes at least a position facing the arrangement of the relay installed on the case main body.
According to the above configuration, since the sound absorbing material or the sound absorbing molding plate is disposed at a position opposite to the relay arrangement in which the operation sound generated when switching the relay on / off is most easily transmitted, the operation sound is efficiently generated. Can absorb sound.

As described above, according to the present invention, the operation sound of the relay or the like generated in the case is absorbed by the sound absorbing material provided on the inner surface or the outer surface of the main body or the cover in the case. It is possible to prevent the operation sound from being heard. As a result, even if the electric junction box is mounted in the vehicle interior, the operation sound does not disturb the passenger. Therefore, the electrical junction box can be mounted not only outside the passenger compartment such as the engine room but also inside the passenger compartment, so that the degree of freedom in designing the wire harness can be improved. . In addition, the weight of the vehicle can be reduced by reducing the number of wires, which contributes to improved fuel efficiency.
In addition, since a semiconductor switching element that does not generate operation noise is not used, an electrical junction box can be formed at low cost.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of the present invention. An electrical junction box 10 includes a bus bar and an insulating plate formed by punching a conductive metal plate into a required shape inside a cover made up of an upper cover 11 and a lower cover 12. The case main body 13 provided with the laminated body laminated | stacked alternately as an internal circuit is accommodated. The case body 13 houses a mechanical relay 14 and the like, and a tab (not shown) formed by bending the end of the bus bar is connected to a terminal of the relay 14.

  A sound absorbing material made of foamed resin (foamed urethane) 20 having a required thickness is bonded to the upper cover 11 with an adhesive 21 over substantially the entire inner surface.

  According to the above configuration, the mechanical sound generated when the mechanical relay 14 is switched on and off can be absorbed by the foamed resin 20 provided on the inner surface of the upper cover 11.

The foamed resin 20 may be welded to the inner surface of the upper cover 11 by ultrasonic welding, or may be fixed by mechanical means such as screwing.
Further, the foamed resin 20 is not limited to the inner surface of the upper cover, and may be provided on the outer surface of the case body or the cover.

  FIG. 2 shows a modification of the first embodiment of the present invention, in which a sound absorbing material mounting portion 15 is projected on the inner surface of the upper cover 11, and a foam metal (foamed foam) is formed on the front end surface in the same manner as in the first embodiment. A sound-absorbing material consisting of 22) is bonded. The sound absorbing material mounting portion 15 is provided at a position facing the relay 14 that generates an operation sound.

According to the above configuration, since the sound absorbing material mounting portion 15 protrudes at a position facing the relay 14 where the operation sound is most easily transmitted, and the foam metal 22 is bonded to the front end surface of the sound absorbing material mounting portion 15, the relay Therefore, the metal foam can be disposed closer to 14 and the operation sound generated from the relay 14 can be efficiently absorbed.
In addition, by arranging the foam metal 22 in the vicinity of the relay 14 and efficiently absorbing sound, it is not necessary to provide the foam metal 22 over the entire inner surface of the upper cover 11. Such labor can be reduced.
Even when the sound absorbing material mounting portion is provided, the sound absorbing material may be provided over substantially the entire inner surface of the upper cover.

  FIG. 3 shows a second embodiment of the present invention, in which a sound-absorbing molding plate 30 having a large number of concave portions 30a and convex portions 30b formed on the inner surface of an upper cover 11 similar to the first embodiment is fixed with an adhesive. ing. The height of the convex portion 30b of the molded plate for sound absorption 30 and the area of the tip end surface of the convex portion and the deepest surface of the concave portion are formed to correspond to the generation frequency to be absorbed, so that a plurality of types of generated frequencies can be absorbed. A plurality of uneven portions having different heights and areas are formed.

  According to the above configuration, the Helmholtz resonator is formed by the sound absorbing molding plate 30 and the upper cover 11, and the operating sound of the relay 14 is absorbed by the resonance action of the air in the recess 30a. Can be prevented. Further, since the height of the convex portion 30b of the molded plate for sound absorption 30 and the area of the convex tip surface and the deepest surface of the concave portion are formed corresponding to the frequency to be absorbed, sound can be absorbed efficiently.

FIG. 4 shows a third embodiment of the present invention, in which a sound-absorbing molded plate 40 in which a large number of cylindrical portions 40a are formed is fixed to the inner surface of an upper cover 11 similar to the first embodiment with an adhesive. A hole 40b having a required diameter is formed in the tip surface of the cylindrical portion 40a of the sound absorbing molded plate 40.
Further, the height of the cylindrical portion 40a and the hole diameter of the hole 40b are formed corresponding to the generation frequency to be absorbed, and a plurality of cylindrical portions 40a having different heights and hole diameters are provided so as to be able to absorb a plurality of types of generated frequencies. Forming.
Furthermore, the same foamed resin 20 as that in the first embodiment is adhered to the deepest surface of the cylindrical portion 40a.

  According to the above configuration, the Helmholtz resonator is formed by the sound-absorbing molding plate 40 and the upper cover 11, and the operation sound in the electrical junction box can be absorbed. Further, since the sound absorbing material 20 provided at the deepest portion of the cylindrical portion 40a absorbs the sound that could not be absorbed by the Helmholtz resonator, the operating sound generated in the cover can be reliably absorbed.

FIG. 5 shows a fourth embodiment of the present invention, in which a required concavo-convex portion is formed in a mold for forming the upper cover 11, and the inner surface of the upper case 11 is an concavo-convex surface composed of a concave portion 50 and a convex portion 51. .
Even with this configuration, the operation sound of the relay is absorbed by the resonance action of the air in the recess 50, and sound leakage outside the electrical junction box can be prevented.

FIG. 6 shows a fifth embodiment of the present invention, in which a cylindrical portion 60 similar to that of the third embodiment is integrally formed on the inner surface of the upper case 11.
Even with this configuration, the operation sound of the relay is absorbed by the cylindrical portion 60, and sound leakage outside the electrical junction box can be prevented.

Hereinafter, examples and comparative examples of the sound absorbing structure of the present invention will be described in detail.
The sound pressure measurement results of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1 below.

(Example 1)
The same sound absorbing structure as that of the first embodiment, that is, the fixed case 70 is placed on the relay 14 with the foamed resin 20 on the inner surface. A distance of 10 mm was provided between the relay 14 and the inner surface of the case 60.
(Example 2)
The same sound absorbing structure as that of the second embodiment, that is, a case 60 in which a sound absorbing molded plate having an uneven portion is fixed to the inner surface is covered with the relay 14.
Other configurations were the same as those in Example 1.
(Example 3)
The same sound-absorbing structure as that of the fourth embodiment, that is, a case 60 in which concave and convex portions are integrally formed on the inner surface is covered with the relay 14.
Other configurations were the same as those in Example 1.

(Comparative Example 1)
The case 14 was not put on the relay 14.
(Comparative Example 2)
The relay 60 was covered with a case 60 that does not have a sound absorbing structure.
Other configurations were the same as those in Example 1.

(Sound pressure measurement method)
A measuring instrument (microphone) 61 (RION SOUND LEVEL MASTAL NL-22) was installed at a position 200 mm above the relay 14, and the operating sound generated when the relay 14 was operated (ON) and returned (OFF) was measured.
TAKASAGO EX-750L2 was used as a relay operating power source, and the voltage applied to the relay coil was set to 14.0V. The measurement range was A characteristic, FAST range, Max, Hold, and background noise was about 20 dB.

  As is clear from Table 1, Examples 1 to 3 in which the case provided with the sound absorbing structure was placed on the relay were compared with Comparative Example 1 in which the case was not provided and Comparative Example 2 in which the sound absorbing structure was not provided. In either case, it was possible to absorb and reduce the operation sound generated at the time of operation and return of the relay. In particular, in Examples 1 to 3, it was possible to further reduce the operation sound at the time of return larger than the operation sound at the time of operation of the relay 14.

It is drawing which shows 1st Embodiment of this invention. It is drawing which shows the modification of 1st Embodiment. It is a principal part enlarged view of 2nd Embodiment of this invention. It is a principal part enlarged view of 3rd Embodiment of this invention. It is a principal part enlarged view of 4th Embodiment of this invention. It is a principal part enlarged view of 5th Embodiment of this invention. It is drawing which shows a sound pressure measuring method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electrical junction box 11 Upper cover 12 Lower cover 13 Case main body 14 Relay 20 Foamed resin 30 and 40 Molding board 30a for sound absorption 30a Concave part 30b Convex part 40a Cylindrical part 40b Hole 50 Concave part 51 Convex part

Claims (4)

  A sound absorbing material is attached to the inner surface or the outer surface of the case main body in which the internal circuit and the electronic components connected to the internal circuit are accommodated or the cover that covers the case main body, and the sound absorbing material is a resin or metal foam, An electrical junction box comprising a sound-absorbing molded plate formed with uneven portions or a sound-absorbing molded plate formed with a large number of cylindrical portions.   A sound absorbing portion is integrally formed on the inner wall or the outer wall of the case main body in which the internal circuit and the electronic components connected to the internal circuit are accommodated, or the cover that covers the case main body. An electrical junction box comprising a cylindrical portion.   The length and hole diameter of the cylindrical portion, the height and area of the concavo-convex portion are formed corresponding to the generation frequency at which sound absorption is desired, and a sound absorbing material made of a foam material is disposed on the deepest surface of the cylindrical portion. The electrical junction box according to claim 1 or claim 2.   The arrangement position of the sound-absorbing material or the sound-absorbing molding plate attached to the case main body or the cover includes at least a position facing the arrangement of the relay installed on the case main body. Electrical junction box.

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