JP3724433B2 - Resin casting type electrical equipment with direct connector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin casting type electric device with a direct connector in which a casting resin is filled in the case in a state where the direct connector is attached to the opening of the case in which the electric device main body is accommodated. .
[0002]
[Prior art]
Conventionally, for example, a battery charging device used in a two-wheeled vehicle or the like is filled with a casting resin in a state in which an electric device main body such as a battery charging device main body using a power element is accommodated in an aluminum case. In resin-cast type electrical equipment, a wire harness is used for electrical connection with the outside, it is pulled into the case via a rubber grommet, and is electrically connected to the electrical equipment body, and then cast into the case. A structure filled with a resin was common.
[0003]
In such resin-casting electrical equipment, if a resin with physical properties very similar to the linear expansion coefficient of the aluminum case is selected as the casting resin, expansion and contraction due to temperature changes will occur via a grommet, which is a rubber molded product. Since it was transmitted to the wire harness, it was relaxed by the expansion and contraction of the grommet, and no problem occurred.
[0004]
Recently, however, resin-casting electric devices with direct connectors as shown in FIGS. 4 to 6 are used due to market needs for space saving, waterproofing and cost reduction. In this case, FIG. 4 is a bottom view of the resin cast type electric device with a direct connector, FIG. 5 is a plan view of FIG. 4, and FIG. 6 is an enlarged view of a portion B of FIG.
[0005]
In this resin cast type electric device with a direct connector, the direct connector 1 which is a resin molded product is inserted into the opening 2a of the aluminum case 2, and the convex mounting portion 3 of the opening 2a of the aluminum case 2 is recessed into the concave portion of the direct connector 1. A fitting portion 4 of the shape is fitted and attached, the terminals of the direct connector 1 are electrically connected to the electric device main body in the aluminum case 2, and the casting resin 5 is filled in the aluminum case 2 in such a state. A plurality of cooling fins 6 are provided on the outer surface of the projection. In this case, an epoxy resin having physical properties very similar to the linear expansion coefficient of the aluminum case 2 is selected as the casting resin 5. The aluminum case 2 is provided with a mounting hole 2b.
[0006]
[Problems to be solved by the invention]
However, since the linear expansion coefficient of the direct connector 1 is different from the linear expansion coefficient of the aluminum case 2 or the casting resin 5 in the conventional resin cast type electric equipment with a direct connector, the battery charger main body using a power element is used. Due to the expansion and contraction of the casting resin 5 due to the temperature change of the electrical equipment body as described above, the internal stress of the casting resin 5 increases, and the inner surface of the aluminum case 2 and the concave shape of the direct connector 1 as shown in FIG. There was a problem that a crack occurred in the casting resin 5 filled in the narrow gap 7 facing the mounting portion 4, and this crack grew and caused dielectric breakdown.
[0007]
As a means for solving this problem, there is a method of using a urethane-based resin having a low elastic modulus as the casting resin 5. However, since the urethane-based resin has low thermal conductivity, a battery charging device using a power element is used. When a large amount of heat is generated as in an electric device main body such as a main body, there is a problem that a diode or thyristor as a power element exceeds its allowable temperature and is destroyed.
[0008]
In addition, since the urethane-based casting resin 5 has a large linear expansion coefficient, stress is applied to the soldering portion that is disposed on the upper side and joins the printed circuit board of the main body of the electrical equipment to the diode chip or thyristor chip that is the power element. There was a risk of cracks occurring in the soldered portion.
[0009]
Adhesion between the aluminum case 2 and the heat sink on which the diode chip or thyristor chip, which is a power element, is mounted requires epoxy resin to ensure heat dissipation, but different resins are applied to the upper and lower layers. In order to perform the molding operation, different filling facilities must be installed, and there is a problem that the curing time of the resin becomes long.
[0010]
An object of the present invention is to provide a resin-casting electric device with a direct connector that does not crack in the casting resin near the direct connector even if expansion and contraction due to temperature change occur.
[0011]
[Means for Solving the Problems]
In the present invention, the electric device main body is accommodated in the case, the attachment portion of the direct connector is attached to the attachment portion of the opening of the case, and the terminal of the direct connector is electrically connected to the electric device main body, and is injected into the case. The present invention is to improve a resin casting type electric device with a direct connector filled with a mold resin.
[0012]
In the resin cast type electric apparatus with a direct connector according to the present invention, an adhesive having a lower elastic modulus than that of the cast resin is applied to a portion where the inner surface of the case and the mounting portion of the direct connector face each other.
[0013]
In such resin-casting electrical equipment with a direct connector, when expansion and contraction due to temperature changes are repeated, the elastic modulus is higher than that of the casting resin in the narrow part where the inner surface of the case and the mounting part of the direct connector face each other. Since a low adhesive is applied, the displacement caused by the difference in linear expansion coefficient between the case and the casting resin and the direct connector can be absorbed by this adhesive, and the casting resin is prevented from cracking. be able to.
[0014]
In addition, it is not necessary to use a urethane-based resin with a low elastic modulus as the casting resin, and an epoxy resin with good heat dissipation can be used. It is possible to avoid being destroyed beyond.
[0015]
In addition, according to the present invention, a stress is applied to the soldered portion of the power element due to a temperature rise caused by the use of a urethane-based resin having low thermal conductivity, and the soldered portion is cracked. It can be avoided by using a casting resin such as a good epoxy resin.
[0016]
Furthermore, in the present invention, it is not necessary to fill different types of resins in the case, and therefore it is not necessary to install different filling facilities, and the resin curing time can be shortened.
[0017]
In addition, when the electric device body is configured using a power element, the temperature rise increases, but in the present invention, a cast resin such as an epoxy resin with good heat dissipation can be used without any problem, so the problem due to the temperature rise A point can be avoided.
[0018]
Further, when the case is an aluminum case, the linear expansion coefficient is close to that of an epoxy resin that is a casting resin, and the heat dissipation performance is good.
[0019]
Further, when the casting resin is an epoxy resin, the linear expansion coefficient is very similar to that of the aluminum case, the heat dissipation is good, and the problems caused by the casting resin can be solved.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
1 to 3 show an example of an embodiment of a resin-casting type electric apparatus with a direct connector according to the present invention, and FIG. 1 is a bottom view of the resin-casting type electric apparatus with a direct connector of this example. 2 is a longitudinal sectional view of FIG. 1, and FIG. 3 is an enlarged view of part A of FIG. Note that portions corresponding to those in FIGS. 4 to 6 are denoted by the same reference numerals.
[0021]
In the resin cast type electric device with direct connector of this example, the elastic modulus is lower than that of the cast resin 5 such as epoxy resin in the narrow gap where the inner surface of the aluminum case 2 and the mounting portion 4 of the direct connector 1 face each other. A rubber adhesive 8 is applied.
[0022]
A heat sink 9 is adhered and fixed to the ceiling surface in the aluminum case 2 with an adhesive 10 such as an epoxy resin. A diode chip 11 and a thyristor chip 12 are attached to the heat sink 9 by soldering. A printed circuit board 13 is disposed in the aluminum case 2 in parallel with the heat sink 9, and the diode chip 11 and the thyristor chip 12 are electrically connected to the printed circuit board 13 by soldering. The printed circuit board 13 is fixed to the direct connector 1 with screws 14.
[0023]
Further, the terminals of the direct connector 1 are electrically connected to the printed circuit board 13. In this state, the aluminum case 2 is filled with an epoxy resin having physical properties close to the linear expansion coefficient of the aluminum case 2 and good heat dissipation as the casting resin 5. In particular, in the case of the aluminum case 2, it is preferable to use an epoxy resin very similar to the linear expansion coefficient of the aluminum case 2 as the casting resin 5.
[0024]
In this example, the electric device main body 15 is constituted by the heat sink 9 and the printed board 13 to which the diode chip 11 and the thyristor chip 12 are attached.
[0025]
In such a resin casting type electric device with a direct connector, when the expansion and contraction due to temperature change are repeated, the casting resin is placed in a narrow portion where the inner surface of the aluminum case 2 and the mounting portion 4 of the direct connector 1 face each other. Since the adhesive 8 having a lower elastic modulus than 5 is applied, the adhesive 8 can absorb the displacement caused by the difference in linear expansion coefficient between the aluminum case 2 and the casting resin 5 and the direct connector 1. It is possible to avoid cracks in the casting resin 5.
[0026]
In addition, it is not necessary to use a urethane-based resin having a low elastic modulus as the casting resin 5, and an epoxy resin having a good heat dissipation can be used. It is possible to avoid destruction exceeding the temperature.
[0027]
Furthermore, the stress rises due to the temperature rise associated with the use of the casting resin 5 made of urethane resin having low thermal conductivity, and the soldering portion of the power element is cracked. This can be avoided by using a casting resin 5 such as a good epoxy resin.
[0028]
Further, when the electric device main body 15 is configured by using the power element, the temperature rise becomes high. However, in the present invention, the casting resin 5 such as an epoxy resin having good heat dissipation can be used without any problem. The problem due to can be avoided.
[0029]
Further, if the case 2 is an aluminum case with a cooling fin 6, the linear expansion coefficient is close to that of the epoxy resin or the like that is the casting resin 5, and heat is dissipated by the presence of the cooling fin 6 in addition to the good heat dissipation by aluminum. The performance can be further improved.
[0030]
Moreover, when the casting resin 5 is an epoxy resin, the linear expansion coefficient is very similar to that of the aluminum case 2 and the heat dissipation is good, so that the problems caused by the casting resin 5 can be solved.
[0031]
Furthermore, there is no need to fill the case 2 with different types of resins, and therefore there is no need to install different filling facilities, and the resin curing time can be shortened.
[0032]
The case 2 may not have the cooling fins 6 depending on the heat generation temperature of the electric device main body 15.
[0033]
The electric device main body 15 accommodated in the case 2 is, for example, a battery charging device main body using a power element that rectifies the output of a magnetic AC generator and supplies power to a load. Is not limited to this, and may be an ignition coil using a power element for igniting the internal combustion engine.
[0034]
【The invention's effect】
In the resin cast type electric device with a direct connector according to the present invention, when expansion and contraction due to temperature change are repeated, the elastic modulus is higher than that of the cast resin in a narrow portion where the inner surface of the case and the mounting portion of the direct connector face each other. Since a low adhesive is applied, displacement caused by the difference in linear expansion coefficient between the case and the casting resin and the direct connector can be absorbed by this adhesive, and cracks are avoided in the casting resin. can do.
[0035]
In addition, it is not necessary to use a urethane-based resin with a low elastic modulus as the casting resin, and an epoxy resin with good heat dissipation can be used. It is possible to avoid being destroyed beyond.
[0036]
Furthermore, stress is applied to the soldered portion of the power element due to the temperature rise caused by the use of urethane resin having low thermal conductivity, and cracks are generated in the soldered portion. It can be avoided by using casting resin.
[0037]
In addition, when the electric device body is configured using a power element, the temperature rise increases. However, in the present invention, a cast resin such as an epoxy resin with good heat dissipation can be used without any problem, so the problem due to the temperature rise. A point can be avoided.
[0038]
Further, in the present invention, it is not necessary to fill the case with different types of resins, and therefore it is not necessary to install different filling facilities, and the resin curing time can be shortened.
[0039]
Further, when the case is an aluminum case, the linear expansion coefficient is close to that of an epoxy resin that is a casting resin, and the heat dissipation performance is good.
[0040]
Further, when the casting resin is an epoxy resin, the linear expansion coefficient is very similar to that of the aluminum case, the heat dissipation is good, and the problems caused by the casting resin can be solved.
[Brief description of the drawings]
FIG. 1 is a bottom view showing an example of an embodiment of a resin casting type electric device with a direct connector according to the present invention.
FIG. 2 is a longitudinal sectional view of FIG.
FIG. 3 is an enlarged view of a portion A in FIG.
FIG. 4 is a bottom view of a conventional resin casting type electric device with a direct connector.
5 is a plan view of the resin-casting electric device with a direct connector shown in FIG. 4. FIG.
6 is an enlarged view of a portion B in FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Direct connector 2 Aluminum case 2a Opening part 2b Mounting hole 3 Convex mounting part 4 Concave mounting part 5 Casting resin 6 Cooling fin 7 Gap 8 Adhesive with low elasticity 9 Heat sink 10 Adhesive 11 Diode chip 12 Thyristor chip 13 Printed circuit board 14 Screw 15 Electrical equipment body

Claims (4)

An electrical device main body is accommodated in the case, a direct connector mounting portion is mounted on the mounting portion of the opening of the case, and the terminal of the direct connector is electrically connected to the electrical device main body, and is injected into the case. In resin casting type electrical equipment with direct connector filled with mold resin,
A resin-casting electric device with a direct connector, wherein an adhesive having a lower elastic modulus than that of the casting resin is applied to a portion where the inner surface of the case and the mounting portion of the direct connector face each other. The resin-casting electric device with a direct connector according to claim 1, wherein the electric device main body is configured using a power element. The resin-casting electric device with a direct connector according to claim 2, wherein the case is an aluminum case with a cooling fin. The resin-casting electric device with a direct connector according to claim 3, wherein the casting resin is an epoxy resin.

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