JP4193974B2 - Airtight terminal unit - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a hermetic terminal unit that combines a hermetic terminal and a connecting wire used in a so-called hermetic or semi-hermetic type electric compressor that drives a compressor with an electric motor in a hermetic container, for example, as a noise countermeasure. Therefore, a new connection part structure is proposed in which a shielded wire is used.
[0002]
[Prior art]
Conventionally, airtight terminals have been widely used as means for electrically connecting the inside and the outside while maintaining the airtight state of the sealed container. In this airtight terminal, the conductive terminal pin inserted in the through hole made in the metal plate is airtightly fixed by an insulating material such as glass, and the airtight terminal is attached to the hole made in the airtight container. The inside and outside can be electrically connected by conductive terminal pins. The airtight terminal can supply electric power from the outside to the electric motor in the sealed container. (For example, see Patent Document 1)
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 63-183282 [0004]
In recent years, automobiles driven by electric motors such as electric vehicles and fuel cell vehicles have been put into practical use. In such an electrically driven vehicle, the driving system of a refrigerant compressor for a car air conditioner is different from the conventional one. In other words, a so-called open type refrigerant compressor that mechanically transmits the rotational force of the engine to the compressor and is driven in an automobile having a so-called engine as in the prior art has been used. In such a drive system, there is little loss when transmitting the driving force of the engine, but the compressor speed is linked to the increase or decrease of the engine speed, so the cooling capacity is adjusted by increasing or decreasing the compressor speed. However, it is necessary to use a variable capacity refrigerant compressor having a complicated mechanism.
[0005]
On the other hand, in an electrically driven vehicle, the use of an electric compressor makes it easy to drive the compressor independently of the traveling system. Therefore, the cooling capacity can be adjusted by controlling the rotation speed of the compressor without using a refrigerant compressor having a complicated mechanism such as a variable capacity type. In addition, some electrically driven vehicles do not use the driving force of a single large motor, but optimize the distribution of driving force by placing an independent motor on each axle and wheel. An electric compressor is also used because it is difficult to share the driving force of the traveling system.
[0006]
[Problems to be solved by the invention]
In such an electric compressor, in order to prevent the refrigerant from leaking, a hermetic or semi-hermetic electric compressor in which the electric motor is housed in a compressor container is used. For example, the hermetic electric compressor can be the same as that used in home air conditioners. However, in an electric vehicle or the like, since the driving power source is a DC power source such as a battery, it is very difficult to obtain an AC power source for driving the induction motor. In the case of a hermetic compressor, it is difficult to simply replace the electric motor with a DC motor. Therefore, in order to drive the AC motor of the electric compressor with a DC power supply, rotation control by an inverter control circuit is required.
[0007]
However, since this inverter control circuit performs a switching operation, the power feeding path becomes a source of electrical noise. In particular, if the power supply cable extends from the inverter circuit long, this cable serves as an antenna, which can cause noise in the car and surrounding radio, and possibly affect other control circuits. There is. Therefore, it is necessary to prevent the generation of noise by grounding this shield using a so-called shielded wire as a power feeding wire to the motor.
[0008]
Further, since this electric compressor is disposed in the engine room of an automobile, it is required that the terminal portion and the connection portion have a waterproof structure. Normally, it is possible to prevent intrusion of water into these charged parts by connecting with a connector having an airtight structure, or by covering the charged parts such as terminals with an electrically insulating filler after connecting the wires to the conductive terminal pins. Yes. However, in the case of connection by a connector, a structure for grounding the shield is required. Therefore, a general-purpose connector cannot be used, and the connector becomes special and the structure becomes complicated and large in size, making it difficult to handle. In addition, when the charging part is covered with an electrically insulating filler, it is necessary to connect the shield part directly or using a terminal or the like in order to ground the shield.
[0009]
In order to solve these problems, the present applicant has proposed an airtight terminal unit in which the shield portion is electrically connected to the ground portion by a conductive filler in Japanese Patent Application No. 2002-259770. In this hermetic terminal unit, the connection portion between the conductive terminal pin of the hermetic terminal and the lead wire is covered with a metal cover, the charging portion is filled with an electrically insulating filler, and the conductive filler is further covered with the electrically conductive filler. The shield and the metal cover are electrically connected by the conductive filler. Here, for example, the cover is connected to a metal part of the body of the automobile which is a grounding part through a metal housing of an electric compressor to be attached. In this way, it is possible to prevent water from entering the charging parts such as the conductive terminal pins by having a structure filled with a filler inside, and between each charging part and other charging parts, metal covers, etc. Even if the distance is small, it can provide sufficient electrical insulation. Further, the shield can be electrically connected to the ground portion without using a special terminal or the like.
[0010]
The structure of this hermetic terminal unit was proposed for one using three airtight terminals. For example, in the case where an additional terminal for a sensor such as a thermistor is provided on the hermetic terminal in addition to feeding, Such a structure is difficult because there is no room inside. That is, when the number of terminals is increased, the arrangement area of the terminals is increased. Therefore, when these terminals are covered with the electrically insulating filler, there is no room for filling the conductive filler in the cover. Also, since there is no room to connect the shield to the cover in the cover, the shield will go out of the cover, and the shield is covered with a filler and waterproofed, as well as being connected to the cover with a conductive filler. It becomes difficult to make the structure. Also, if the area covered by the cover can be increased and the position of the terminal can be made sufficiently deep with respect to the opening of the cover, it can be handled. However, in this case, the area of the sealed terminal must also be increased. It becomes difficult to reduce the size as a unit.
[0011]
In addition, it is necessary to waterproof the connection part in some way so that water does not enter the shield from the place where the shield is connected to the grounding part, but applying the coating agent is troublesome and the workability at the time of manufacture is reduced. There is a problem that it drops greatly. Furthermore, wrapping waterproof tape or the like is also inefficient since the electric wires are close to each other. Also, for example, the shield may be welded directly to the cover in the cover and covered with an electrically insulating filler including the welded portion. However, it is also necessary to weld the core wire of the shielded wire and the airtight terminal inside the cover. In addition, it is very difficult to manufacture because there is no room in the space in the cover. Therefore, there is a need for a sealed terminal unit that can reliably perform insulation waterproofing of the charging unit and grounding the shield, and also has good workability in manufacturing.
[0012]
[Means for Solving the Problems]
Therefore, in the sealed terminal unit of the present invention, the core wire of the power supply shielded electric wire is connected and fixed to one end of the predetermined conductive terminal pin that is fixedly penetrated to the hermetic terminal, and this connection portion is covered with a conductive cover. In the airtight terminal unit that is structured to prevent water and the like from entering the connection part by filling the cover with an electrically insulating filler, electrically connect the metal shield of the shielded wire to a predetermined grounding part , At least the connecting portion of the shield is covered with a heat-shrinkable tube having a thermoplastic resin applied to the inner surface, and is shrunk by heating.
[0013]
Another feature is that in the above-described hermetic terminal unit, the metal shield of the shielded wire is electrically connected to the cover directly or through the conductive connection body, and at least the connection portion of the shield and the conductive connection body is thermally contracted. It is covered with a tube and contracted by heating.
[0014]
Still another feature of the present invention is that, in the above-described hermetic terminal unit using a conductive connecting body , one end of the heat shrinkable tube is embedded in an electrically insulating filler in the cover.
[0015]
[Action]
According to the present invention, it is possible to prevent the intrusion of water into these terminal parts by covering the charging parts such as the power supply wires and the conductive terminal pins covered with the cover on the airtight terminals with the electrical insulating resin, It is possible to prevent water from entering the shielded wire by covering the shield connection portion of the shielded wire with a heat-shrinkable tube whose inner surface is coated with a thermoplastic resin. Therefore, there is no allowance for the arrangement of components inside the cover covering the terminals, and waterproof performance as an airtight terminal unit can be reliably obtained even when the shield is connected to the ground portion outside the cover.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is an airtight terminal unit for electrically connecting the inside and the outside of an airtight container. For example, the airtight terminal unit is used in a semi-hermetic type electric compressor and is fixed to the airtight container by screwing or the like. FIG. 1 is a perspective view showing the appearance of the hermetic terminal unit, and FIG. 2 is a side view thereof. 3 and 4 show a longitudinal sectional view and a transverse sectional view, respectively.
[0017]
The airtight terminal unit 1 has an airtight terminal 2, three shielded electric wires 3 for power feeding connected to the airtight terminal, and a lead wire 4 for transmitting a sensor signal. The hermetic terminal 2 includes a metal plate 5, a power supply conductive terminal pin 6 (hereinafter referred to as power supply pin 6), and a signal conductive terminal pin 7 (hereinafter referred to as signal pin 7). The power supply pin 6 or the signal pin 7 is hermetically sealed and fixed to each of the plurality of through holes 5A provided by an electric insulating material 8 such as glass. In the through hole 5A of the present embodiment, the diameter of the through hole 5A is increased in order to obtain a creepage distance between each power supply pin serving as a charging portion and the metal plate 5 on the side not filled with a filler described later.
[0018]
The shield wire 3 described above is connected and fixed to one end of each power supply pin 6, and the lead wire 4 is connected and fixed to the signal pin 7. As shown in FIG. 5, this shielded electric wire 3 has an inner insulating layer 3B around a central core wire 3A. Further, the inner insulating layer is covered with a conductive net or a foil-like shield 3C, and the outermost periphery is an outer insulator 3D. Covered. Further, in this embodiment, the stranded wire-shaped core wires 3A are gathered together by a fixing metal fitting 3E, and each lead wire 3 is connected and fixed to each power supply pin 6 by welding the fixing metal fitting 3E. Although not shown in the drawings, when used in an electric compressor, a winding of the electric motor is connected to the other end of the power supply pin 6, and a sensor or the like is connected to the other end of the signal pin 7.
[0019]
A metal cover 9 is disposed so as to cover the connection portion. The cover 9 is connected and fixed to the metal plate 5 of the hermetic terminal 2 by a method such as welding, and an inner space is filled with an electrically insulating filler 10 such as an epoxy resin. The electrical insulating filler 10 can improve the insulation performance between the charged parts, and can prevent water from entering the inside and prevent short circuit and internal corrosion. Further, when the airtight terminal unit is attached to the electric compressor, the cover 9 is electrically connected to the ground portion by contacting a flange 9B provided on the periphery with a metal container of the compressor. One end of a conductive connecting body 11 made of a copper alloy or the like is connected and fixed to the inside of the cover 9 by welding or the like, and a grip portion 11A provided at the other end of the conductive connecting body 11 is connected to the shielded electric wire 3. The shield 3C is electrically connected by caulking. Thus, the shielded electric wire 3 electrically connects the shield 3C to the grounding portion through the conductive connector and the cover.
[0020]
The conductive connection body 11 is disposed along the shielded electric wire 3, and both are covered with an electrically insulating heat shrinkable tube 12. The heat shrinkable tube 12 is coated with a thermoplastic resin on its inner surface, and the tube shrinks due to heating to hold the conductive connector and the shielded wire together and fill the gap formed by the softened thermoplastic resin. Thus, water or the like can be prevented from entering the inside, and the shield 3C and the conductive connector 11 can be prevented from corroding.
[0021]
【Example】
Next, the manufacturing procedure of the present invention will be described with reference to the exploded perspective view of FIG. The hermetic terminal 2 of the hermetic terminal unit 1 has a conductive terminal hermetically penetrating through the through hole 5A provided in the metal plate 5 as described above. In this embodiment, three power supply pins 6 and two signal pins are provided. 7 is fixed to each through hole by an electrically insulating material 8 such as glass. A groove 5B for holding a packing such as an O-ring is provided at the periphery of the metal plate 5 in order to obtain hermeticity when the hermetic terminal unit is attached. In addition, a step is provided on the upper side surface of the metal plate in the figure to align with a cover described later, and the periphery is lowered by one step.
[0022]
The core wire 3A of the power supply shielded electric wire 3 is connected and fixed to each power supply pin 6 by a method such as welding, and the core wire of the sensor signal lead wire 4 is similarly connected and fixed to the signal pin 7. In this embodiment, the tip portion of the lead wire 4 is inverted because the position of the signal pin 7 is relatively shallow from the surface of the filler described later, so that the contact area with the filler is increased for waterproofing. Is for. For example, this is not necessary as long as the insulation film of the lead wire and the filler have good affinity and sufficient waterproof performance can be obtained even if the contact area is small.
[0023]
The metal cover 9 has a cylindrical dome portion 9A that covers the terminal connection portion described above and a flange 9B that extends to the peripheral edge of the lower end. The airtight terminal unit 1 is fixed as a whole by fixing the flange 9B of the cover 9 to a device to be attached as will be described later. For example, in the case of an automobile, the cover 9 is provided via a metal housing of an electric compressor. And electrically connected to a grounding part such as a metal part of the body. Inside the dome portion 9A, three conductive connecting bodies 11 are arranged so that their fixed ends 11B are connected and fixed by welding or the like and are parallel to each other. The conductive connection body 11 is made of a thin metal plate or the like, and is arranged along the shielded electric wire 3 fixed to the airtight terminal 2.
[0024]
The cover 9 is fixed to the airtight terminal 2 to which the electric wires are connected, so that both are integrated. As described above, the cover 9 is fixed to the upper surface of the metal plate 5 by welding or the like inside the flange 9B in a state where the conductive connection body 11 is arranged along the shielded electric wire 3. Each shielded electric wire 3 has an outermost outer insulator 3D peeled off so that the shield 3C is exposed at a portion corresponding to the gripping portion 11A of the conductive connecting body 11, and after the cover 9 and the airtight terminal 2 are fixed. The conductive connector and the shield are connected by caulking the grip portion 11A. Thus, since the shield 3C is electrically connected to the cover 9 via the conductive connector 11, the shield 3C is also grounded by connecting the cover 9 to the ground portion. Therefore, even when a driving current for switching by the inverter control circuit is passed through the shielded electric wire 3, noise leaking from the core wire 3A is blocked by the shield 9C, and the influence on the external device can be prevented.
[0025]
After connecting the conductive connection body and the shield in this way, the electrically insulating heat shrinkable tube 12 is covered so as to cover the conductive connection body including this connection portion. A thermoplastic resin is applied to the inside of the heat shrinkable tube 12, and when heated to a predetermined temperature or more, the tube shrinks and the thermoplastic resin softens, and the gap between the tube and the shielded electric wire can be filled with the resin. . Actually, the thermoplastic resin fills the inside of the heat-shrinkable tube and closes the end surface so as to slightly overflow from the end surface of the heat-shrinkable tube 12 as indicated by 12A in FIG. Therefore, intrusion of water or the like into the tube can be prevented.
[0026]
In the present embodiment, a holding portion 9 </ b> C that extends substantially horizontally from the dome portion 9 </ b> A of the cover 9 is provided. The holding portion 9C holds the shielded electric wire 3 and the lead wire 4, and is given strength by attaching ribs in the embodiment. A holding body 13 is fixed to the tip of the holding portion 9C and is supported so as to bundle the shielded electric wire and the lead wire.
[0027]
At the time of manufacture, the shield 3C and the conductive connector 11 are connected, then the heat shrinkable tube 12 is put on, the holder 13 is fixed to the cover holding portion 9C, and the shield wire and the lead wire are bundled. Is filled with an electrically insulating filler 10 such as an epoxy resin. In this embodiment, a thermosetting epoxy resin is used for the electrically insulating filler 10, and the filler is filled before the heat-shrinkable tube is overheated. By heating in this state, the filler is cured. The heat shrink tube is shrinking simultaneously. Therefore, a heating process can be completed at once.
[0028]
The hermetic terminal unit 1 is inserted into a mounting hole of a target device after a packing such as an O-ring is attached to a groove 5B provided in the peripheral portion of the metal plate 5, and is attached to a mounting hole 9D provided in a flange 9B of the cover. The detent is positioned, and is further fixed to withstand the internal pressure by a holding tool such as a presser fitting or a bolt. In this way, the hermetic terminal unit is firmly fixed to the target device by the holder and hermetically sealed by the packing. And even if it is used in an environment where it is washed in this state or is exposed to rainwater, water can be reliably prevented from entering the charging unit.
[0029]
In the above-described embodiment, three conductive connecting members prepared for each shielded wire are used, but this is more than the gap between the connecting members because of the structure of the gripping portion of the conductive connecting member. Although it is necessary to increase the width of the plate, for example, the three conductive connectors may be integrated into the comb mold if the position of the gripping part is shifted back and forth or the gripping part is made small so as to eliminate restrictions. Moreover, if the electrical connection with the shield can be ensured by contact by tightening with a heat-shrinkable tube or mediation of a conductive paste, it is easier to integrate the conductive connector. Further, for example, the conductive connecting body is omitted by making the holding portion 19C thin so that it can be inserted into the heat-shrinkable tube like the cover 19 shown in FIG. You can also. In this case, the contact pressure between the holding portion and the shield can be increased by slightly bending the tip of the holding portion 19C toward the shield side.
[0030]
In the above-described embodiment, the entire conductive connection body is described as being covered with a heat-shrinkable tube and an electric insulating resin, but the structure does not allow water to enter the charged portion on the airtight terminal or the shielded electric wire. In addition, if the conductive connector itself has sufficient durability for the period of use and corrosion does not become a problem, it is not always necessary to cover the entire conductive connector.
[0031]
Such an example will be described with reference to FIG. The same parts as those in the above example are denoted by the same symbols, and detailed description thereof is omitted. The sealed terminal unit 21 shown in FIG. 8 has a sealed terminal and a metal cover similar to the above-described example. Inside the cover 9, the core wire of the power supply shielded electric wire 3 is connected to the power supply pin 6 of the hermetic terminal. In this sealed terminal unit, the conductive connection body is not fixed to the cover 9, and the ground wire 33 is fixed to the shield 3 </ b> C of each shielded wire by the fixing bracket 34 and is electrically connected thereto. This connection portion is covered with a heat shrinkable tube 32 having an inner surface coated with a thermoplastic resin so that water does not enter the inside from the shield portion. Although not shown in the figure, the cover 9 is filled with an electrically insulating resin so as to cover the charging portion such as each terminal in the same manner as in the above-described embodiment, thereby forming a waterproof structure.
[0032]
In the present embodiment, the grounding wires 33 are wires covered with an insulating coating, and the respective grounding wires 33 are grouped together by mounting terminals 35 so as to facilitate the connection work to the grounding portion. Therefore, the shield 3C can be reliably grounded by connecting the mounting terminal 35 to an arbitrary grounding portion together with the mounting of the sealed terminal unit 21. According to the present embodiment, when the target device of the sealed terminal unit 21 is not electrically grounded, or when the cover 9 or the metal plate 5 of the sealed terminal is not in contact with the grounded part due to surface treatment or the like. The shield can be easily grounded.
[0033]
【The invention's effect】
Thus, the conductive terminal pin covered with the cover on the airtight terminal and the charging part such as the electric wire connected thereto are covered with the electrically insulating filler, and the shield and the grounding portion of the shielded electric wire which cannot be accommodated in the filler. By covering the connecting part with a heat-shrinkable tube coated with thermoplastic resin on the inner surface, even if there is no allowance for component placement inside the cover, the shield is securely connected to the cover that is the grounding part and as an airtight terminal unit Waterproof performance can be obtained.
[Brief description of the drawings]
1 is a side view of the hermetic terminal unit of FIG. 1. FIG. 3 is a longitudinal sectional view of the hermetic terminal unit of FIG. 1. FIG. Fig. 5 is a cross-sectional view of the unit. Fig. 5 is a shielded electric wire used in the hermetic terminal unit of Fig. 1. Fig. 6 is an exploded perspective view of the hermetic terminal unit of Fig. 1. Fig. 7 is another embodiment of the cover used in the present invention. Example [FIG. 8] Cross-sectional view of another embodiment of the hermetic terminal unit of the present invention [Explanation of symbols]
1, 2: 1: Airtight terminal unit 2: Airtight terminal 3: Shielded wire 3A: Core wire 3C: Shield 4: Lead wire 5: Metal plate 6: Conductive terminal pin 7 for power supply: Conductive terminal pin 9 for signal, 19: Cover 10: Electrical insulating filler 11: Conductive connector 12, 32: Heat shrinkable tube 33: Ground wire

Claims (4)

An airtight terminal that hermetically insulates and fixes conductive terminal pins respectively inserted into a plurality of holes made in the metal plate;
The core wire of the shielded electric wire is connected and fixed to one end of the predetermined conductive terminal pin,
Cover this connection with a conductive cover,
Furthermore, in the airtight terminal unit that is structured to prevent the entry of water and the like into the connection part by filling the cover with an electrically insulating filler,
Electrically connect the metal shield of the shielded wire to the specified grounding part ,
An airtight terminal unit having a watertight structure by covering at least a connecting portion of the shield with a heat shrinkable tube coated with a thermoplastic resin on the inner surface and shrinking by heating. In the airtight terminal unit according to claim 1,
Electrically connect the metal shield of the shielded wire to the inner surface of the cover with a conductive connector,
An airtight terminal unit characterized in that at least a connecting portion between the shield and the conductive connector is covered with a heat shrinkable tube. In the airtight terminal unit according to claim 2,
An airtight terminal unit characterized in that one end of the heat-shrinkable tube reaches the electrically insulating filler in the cover. In the airtight terminal unit according to claim 1,
Connect the metal shield of the shielded cable directly to the cover,
An airtight terminal unit characterized in that at least a connecting portion between the shield and the cover is covered with a heat shrinkable tube.

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