JP4193975B2 - Airtight terminal unit - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a waterproof structure for an airtight terminal used in a so-called hermetic type or semi-hermetic type electric compressor in which a compressor is driven by an electric motor in a hermetic container, for example.
[0002]
[Prior art]
In a hermetic type or semi-hermetic type electric compressor in which an electric motor or a compressor is built in a container and this container is used as a refrigerant passage, as a means for supplying electric power from an external power source to the internal electric motor, a so-called airtight has been conventionally used. Terminal is being used.
[0003]
As an example of this, for example, like the airtight terminal 101 shown in FIG. A, conductive terminal pins 103 are inserted into holes 102A formed in the metal plate 102, and each conductive terminal pin is made of an electrically insulating material 104 such as glass. Airtight and insulated. A lead wire 105 for connecting to a power source is connected and fixed to one end of each conductive terminal pin 103.
[0004]
For example, the hermetic terminal 101 is attached to a hermetic container of an electric compressor in an airtight state. In this example, as shown in FIG. B, the hermetic terminal 101 is fixed to the mounting hole 111A of the hermetic container 111 with a fixing screw 112. The A packing 113 such as a so-called O-ring is disposed on the contact surface between the hermetic terminal 101 and the sealed container 111 so as to surround the mounting hole 111 </ b> A to keep the sealed state.
[0005]
Although not shown, the winding of the electric motor is connected directly or via a lead wire to the inside end of the sealed container of the conductive terminal pin 103. In this way, the airtight terminal 101 can supply an operating current to the electric motor by electrically connecting the inside and the outside of the airtight container such as an electric compressor while maintaining the airtight state.
[0006]
Each conductive terminal pin 103, which is a charging portion through which an operating current flows in the hermetic terminal 101, is electrically connected to other conductive terminals having different potentials depending on the electrically insulating material 104 such as glass and the metal plate 102 which is a non-charging part. Separated. The diameter of the electrically insulating material 104 is set to have a sufficient pressure resistance against the operating voltage applied to the airtight terminal.
[0007]
However, for example, when the electric compressor is used in an automobile or the like, water droplets may be applied to the airtight terminal depending on the installation location. Therefore, there is a countermeasure such as covering the terminal with a cap-shaped waterproof housing or a terminal cover. In this case as well, the lead wire penetrates the waterproof housing, so that the gap between the lead wire and the housing is closed with a gasket or rubber bush to prevent water from entering the penetration. is there. (For example, refer to Patent Document 1 and Patent Document 2) In addition, there is a case where a connection portion between a conductive terminal pin and a lead wire is covered with a heat-shrinkable insulating coating. (For example, see Patent Document 3)
[0008]
[Patent Document 1]
JP-A-2-108875 [0009]
[Patent Document 2]
JP-A-4-334944
[Patent Document 3]
JP-A-5-256261 [0011]
[Problems to be solved by the invention]
In rare cases, however, moisture inside these waterproof housings may condense on the airtight terminals. This is thought to be due to moisture entering through the inside of the lead wire penetrating the waterproof housing. This is because a lead wire usually used for these purposes needs flexibility, and a core wire obtained by bundling a plurality of thin wires having a wire diameter covered with an electrically insulating coating is used. It is estimated that moisture enters the cap as water vapor through a slight gap between the wires. And especially when exposed to high-temperature and high-humidity conditions, that is, when the saturated vapor pressure is high, moisture enters the gas in the waterproof housing and the humidity rises, the saturated vapor pressure in the waterproof housing decreases and the gas decreases when the temperature decreases. The water vapor inside is condensed.
[0012]
When such a phenomenon occurs, it becomes possible for electricity to flow following the dew condensation generated on the surface of the electrically insulating material 104 of the hermetic terminal 101, so that the operation of the motor becomes impossible due to electric leakage or a short circuit or the output is reduced. May decrease. As a countermeasure, there are methods such as covering the charging parts such as conductive terminal pins with an electrically insulating filler such as synthetic resin, but covering the terminal part directly with a filler controls the flow and wraparound of the filler. In addition, it is difficult to cover the inside with a cap or the like so that the number of parts and the amount of the filler are increased, which also takes time in manufacturing.
[0013]
Even when covered with a heat-shrinkable insulation coating, there are irregularities in the shape of the connection part between the conductive terminal pin and the lead wire, so that a gap is created inside even after shrinkage, and the end surface of the insulation coating is in close contact with the electrically insulating material of the airtight terminal It is practically difficult to contract. Therefore, there is a need for an airtight terminal that is easy to manufacture and has a structure that can reliably insulate the charged part.
[0014]
[Means for Solving the Problems]
Therefore, the hermetic terminal unit of the present invention has a hermetic terminal in which a conductive terminal pin is hermetically insulated and fixed to a metal plate, and a lead wire connected to the conductive terminal pin of the hermetic terminal, and connection between the conductive terminal pin and the lead wire The heat-shrinkable insulation coating is covered by heat shrinkage on the part, and the inner surface of this heat-shrinkable insulation coating is pre-coated with a thermoplastic resin that softens at the shrinkage temperature of the heat-shrinkable insulation coating. In the airtight terminal unit that fills the gap in the heat-shrinkable insulation coating with the thermoplastic resin when the heat-shrinkable insulation coating is heat-shrinked, the amount of the thermoplastic resin in the heat-shrinkable insulation coating is The amount of overflowing thermoplastic resin fills the gap between the end of the heat-shrinkable insulation coating and the electrically insulating material on the airtight terminal. Characterized in that the side of the conductive terminal pins covered edge coating completely covers.
[0015]
In this way, the amount of the thermoplastic resin applied is slightly overflowed from the end when the heat-shrinkable insulating coating shrinks, thereby filling a gap formed between the end of the insulating coating and the electrically insulating material of the airtight terminal. And can completely cover the charged part.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the structure of the hermetic terminal unit of the present invention will be described with reference to FIGS. 1 and 2. The hermetic terminal unit 1 includes a metal plate 2 and a hermetic terminal in which a metal conductive terminal pin 3 is inserted into a hole 2A formed in the metal plate 2 and is hermetically insulated and fixed with an electrically insulating material 4 such as glass. have. A lead wire 5 for connection to a power source is connected and fixed to one end of each conductive terminal pin 3. In this embodiment, in order to obtain flexibility, the lead wire 5 is a core wire made of a bundle of a plurality of strands having a thin wire diameter and covered with an insulating coating, and the tip of the core wire is fixed with a fixing bracket. The fixing metal fitting is welded to the conductive terminal pin 3 by caulking.
[0017]
The hermetic terminal unit 1 is attached to an airtight container of an electric compressor. For example, as shown in FIG. 2, the airtight terminal unit 1 is fastened and fixed to an attachment hole 111A of the airtight container 111 with a fixing screw 112. On the contact surface between the hermetic terminal unit 1 and the sealed container 111, a packing 113 such as a so-called O-ring is disposed so as to surround the mounting hole 111A, and the sealed state is maintained.
[0018]
In the present invention, the connecting portion between the conductive terminal pin 3 and the lead wire 5 which is outside the sealed container is covered with an electrically insulating heat-shrinkable insulating coating 6. The heat-shrinkable insulation coating 6 has a tube shape before shrinkage, and an electrically insulating thermoplastic resin 6A is applied to the inner surface of the heat-shrinkable insulation coating 6A. When heated, the heat softens and fills the gaps remaining in the heat-shrinkable insulation coating. In addition, the viscosity at the time of softening is such that the heat-shrinkable insulation coating is extruded by the heat-shrinkable insulation coating during shrinkage heating, but it is not so low that it flows down due to its own weight. Is set to such an extent that it does not deform downflow.
[0019]
Therefore, the thermoplastic resin 6A softened during the contraction overheating operation of the heat-shrinkable insulating coating 6 has a slight gap between the inner surface of the heat-shrinkable insulating coating and the surface of the lead wire 5 and the heat remaining. A gap between the shrinkable insulation coating and the surface of the conductive terminal pin 3 can be filled, and a gap between the core wires can be filled at least near the tip of the lead wire 5. Even when the connecting portion between the lead wire and the conductive terminal pin is covered with a waterproof cap or the like by covering the tip end portion of the lead wire 5 and filling the gap between the core wires, moisture can be contained in the cap inside the cap. Intrusion through is prevented. Therefore, it is possible to prevent the occurrence of condensation on the hermetic terminal and to prevent leakage and short circuit.
[0020]
Further, in this airtight terminal unit 1, the amount of the thermoplastic resin 6A applied is slightly overflowed from both ends due to the shrinkage of the heat-shrinkable insulating coating 6, and particularly at the lower end in the figure, the heat-shrinkable insulating coating 6 and the electric resin are electrically discharged. The conductive terminal pin 3 is completely covered by filling the gap with the insulating material 4.
[0021]
Therefore, in the airtight terminal unit 1 of the present embodiment, for example, in the case where condensation occurs at this terminal portion, even when the terminal is placed in an environment where water droplets are directly applied to the terminal portion, the heat-shrinkable insulation coating and the thermoplastic resin Can prevent water from coming into direct contact with the charging part.
[0022]
In the above-described embodiments, the lead wire bundled with thin electric wires has been described as an example, but even a single wire can fill the gap between the core wire and the insulation coating, and charging portions such as terminals Of course, the same effect is obtained in that the entire structure can be made waterproof. Needless to say, the hermetic terminal unit is not limited to those fixed with screws, but can be applied to those fixed by various methods such as mounting jigs and welding.
[0023]
【The invention's effect】
According to the hermetic terminal unit of the present invention, an electrically insulating thermoplastic resin coated in the heat-shrinkable insulating coating and covering the terminal connection portion by a simple method can fill the gap at the tip of the lead wire, It is possible to prevent moisture from reaching the terminal portion through the inside of the lead wire. Also, by filling the thermoplastic resin coating amount slightly from the end when the heat-shrinkable insulating coating shrinks, the gap created between the end of the insulating coating and the electrically insulating material of the airtight terminal is filled. And can completely cover the charged part. Therefore, reliable and sufficiently high waterproof performance can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a hermetic terminal unit of the present invention. FIG. 2 is a cross-sectional view showing a mounting state of the hermetic terminal unit of FIG. 1. FIG. ] Cross-sectional view showing the mounting state of the airtight terminal of FIG.
1: Airtight terminal unit 2: Metal plate 3: Conductive terminal pin 4: Electrical insulating material 5: Lead wire 6: Heat shrinkable tube 6A: Thermoplastic resin

Claims (1)

An airtight terminal in which a conductive terminal pin is airtightly insulated and fixed with an electrically insulating material on a flat metal plate;
It has a lead wire connected to the conductive terminal pin of this airtight terminal,
The connection portion between the conductive terminal pin and the lead wire is covered with a tube-shaped heat-shrinkable insulation coating by heat shrinkage,
The inner surface of this heat-shrinkable insulating coating is preliminarily coated with an electrically insulating thermoplastic resin that softens at the shrinkage temperature of the insulating coating,
In the airtight terminal unit that fills the gap in the insulation coating with the thermoplastic resin at the time of heat shrinkage of the heat shrinkable insulation coating ,
The amount of thermoplastic resin applied in the heat-shrinkable insulation coating is designed to overflow slightly from both ends when the heat-shrinkable insulation coating shrinks.
This overflowing thermoplastic resin completely fills the gap between the end of the heat-shrinkable insulation coating and the electrically insulating material on the airtight terminal, thereby completely covering the conductive terminal pin on the side covered with the heat-shrinkable insulation coating. Airtight terminal unit characterized by covering.

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