JP6326300B2 - Circuit break structure of power cable - Google Patents

Description

  The present invention relates to a circuit breaking structure for a power cable.

Conventionally, electric vehicles such as electric vehicles, hybrid vehicles, and fuel cell vehicles equipped with a motor as a driving power source are known. In such an electric vehicle, direct-current power supplied from a vehicle-mounted battery is converted into alternating-current power by a power conversion device such as an inverter and applied to the motor. And the electric vehicle which improves a high voltage | pressure safety is proposed by making the electric power cable which connects a power converter device and a motor at the time of a collision of an electric vehicle safely (for example, refer patent document 1).
Such an electric vehicle includes a case that houses a power conversion device that is arranged in a drive unit accommodation chamber and transfers power to and from the motor, and a power cable that electrically connects the power conversion device and the motor. In the electric vehicle, as shown in FIG. 6, the power cable P (P 1, P 2) connects the case side connector 501 and the motor side connector 503. As shown in FIG. 7, the power cable P includes a conductive core wire 505 and a covering portion 507 that is formed of a material having a higher elongation rate than the core wire 505 and covers the periphery of the core wire 505. The core wire 505 is provided with a core wire expected break portion 509 that is easily broken when a tensile force T1 is applied in the event of a vehicle collision. A planned fracture portion 511 is provided on the motor side.

  Both the planned break portion of the core wire 505 and the planned break portion of the covering portion 507 in the power cable P are configured by a cut portion 513. These cut portions 513 reduce the tensile strength of the core wire 505 and the covering portion 507 and make the core wire 505 and the covering portion 507 easy to break or break at the time of a vehicle collision.

  When the case moves and a tensile force T1 acts on the power cable P at the time of a vehicle collision, first, a breakage occurs in the core wire breakage scheduled portion 509 having a relatively low elongation rate, and then a coating breakage scheduled portion where the elongation rate is relatively large. Break occurs at 511. In this way, in the power cable P, since the core wire 505 is disconnected first on the case side, the power supply from the power conversion device to the motor is cut off, so that the covering portion 507 is later broken on the motor side and the core wire 505 is exposed. There is no danger to high voltage.

  Further, as shown in FIG. 8, in another example of the power cable P, the weakened portion 515 whose brittleness is higher than the other core wire portions without reducing the cross-sectional area of the core wire 505 is the power cable as the planned break portion. A P core wire 505 is provided. According to this example, the power cable P can be safely disconnected, and an increase in resistance and heat generation in the fragile portion 515 can be reduced.

JP 2013-219862 A

  However, when the cut portion 513 is provided to make a shape that is easy to break, there is a restriction such as securing a cross-sectional area necessary for energization, so the cut shape cannot be increased and the degree of design freedom is small. Similarly, when the brittle portion 515 made of a brittle material is provided in a part of the conductor, a large difference cannot be set in the tensile strength only by the difference in the ductile / brittle material, and the degree of freedom in design is small.

  The present invention has been made in view of the above situation, and the object of the present invention is to provide a power cable that can be easily broken without securing a degree of design without using a notch shape or a brittle material. The object is to provide a circuit interruption structure.

The above object of the present invention is achieved by the following configuration.
(1) Between the two conductors of the main wire divided at a predetermined position, a plurality of small-diameter wires having a smaller current cross-sectional area than that of the main wire and having different lengths are provided side by side. A circuit breaker structure for a power cable, wherein a branch connection portion having a current cross-sectional area greater than a current cross-sectional area is provided.

According to the circuit breaking structure of the power cable configured as described in (1) above, the branch connection portion is configured such that the energization cross-sectional area is greater than or equal to the energization cross-sectional area of the main electric wire by providing a plurality of small-diameter wires. . When the main electric wire connected via the branch connection portion is pulled, a tensile force is equally applied to each of the main electric wire and the branch connection portion. In the branch connection portion, since the lengths of the plurality of small-diameter wires each having a smaller current cross-sectional area than the main wire are different, first, the shortest-side thin wire reaches the breaking limit first. As a result, when the main electric wire is pulled, the shortest-side thin-diameter electric wire becomes a portion where the wire is first disconnected. Next, the second shortest diameter wire reaches its limit and breaks. And when all the several small diameter electric wires of a branch connection part are fractured | ruptured from the short side, a main wire will be parted by a branch connection part.
Therefore, in the circuit breaker structure of the power cable having the above-described configuration, the main electric wire can be surely divided at the branch connection portion when a predetermined tensile force or more is applied to the main electric wire. Therefore, it is only necessary to take insulation protection measures around the branch connection portion, and it is possible to effectively take measures for insulation protection and electrical safety. In addition, while ensuring the cross-sectional area required for energization, the desired breaking strength can be easily set by changing the thickness, length, etc. of the multiple small-diameter wires at the branch connection part, and the degree of freedom in design Is big.

(2) A circuit breaker structure for a power cable configured as described in (1) above, wherein a predetermined length portion of the main wire inserted through the branch connection portion and connected to both ends of the branch connection portion is provided. A cylindrical insulating protective housing for receiving, and an end insulating housing for holding a predetermined length portion of the main electric wire movably in the electric wire insertion direction with respect to the insulating protective housing. Circuit interruption structure.

  According to the circuit breaker structure of the power cable having the configuration of (2) above, when a tensile force is applied to the main electric wire whose branch connection portion is covered by the cylindrical insulating protective housing, the end insulating housing together with the main electric wire By sliding relative to the insulating protective housing, the tensile force can act on the branch connection. And the insulation protection housing which covers a branch connection part can perform insulation protection at the time of the tensile fracture of a power cable reliably.

(3) The circuit breaker structure for the power cable configured as described in (2) above, wherein the end insulating housing is moved at a predetermined length in the wire insertion direction with respect to the insulating protective housing at both ends of the insulating protective housing. A circuit breaker structure for a power cable, characterized in that an extra length portion is provided.

  According to the circuit breaking structure of the power cable having the configuration of (3) above, the end insulating housing is detached from the extra length of the insulating protective housing when the main cable moves within a predetermined length when the power cable is pulled and broken. Therefore, it is possible to prevent the broken conductor portion of the branch connection portion from coming out of the insulating protective housing.

  According to the circuit breaker structure for a power cable according to the present invention, it is possible to provide a portion that is easily broken without securing a degree of design without using a notch shape or a brittle material.

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

It is a disassembled perspective view showing the circuit interruption | blocking structure of the electric power cable which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view showing the circuit interruption | blocking structure of the electric power cable shown in FIG. It is an expansion perspective view of the branch connection part shown in FIG. It is a top view of the branch connection part shown in FIG. It is a principal part expansion perspective view of the branch connection part shown in FIG. It is a schematic diagram of the case side connector in the electric vehicle of a prior art example, a motor side connector, and the electric power cable routed among them. It is sectional drawing showing a mode when the tensile force acts on the power cable shown in FIG. It is sectional drawing of the other conventional example by which a core wire fracture plan part is comprised by a weak part.

Embodiments according to the present invention will be described below with reference to the drawings.
As shown in FIGS. 1 and 2, the circuit breaker structure for a power cable according to an embodiment of the present invention is a branch connection provided between the conductors of the main wire 17 and the main wire 17 divided at a predetermined position. Part 11, insulating protective housing 23, and end insulating housing 25.

  Main electric wire 17 is a power cable for connecting a motor and a power converter in an electric vehicle. As shown in FIG. 3, the main electric wire 17 has a main electric wire conductor 27 covered with a covering 29. A motor (not shown) of the electric vehicle is disposed in the drive unit accommodation chamber. The power conversion device (not shown) is housed in a case provided in a part of the vehicle body different from the drive unit housing chamber. These motors and the power converter are connected by a power cable composed of the main electric wire 17 and the branch connection portion 11. The main electric wire 17 is connected to the motor via a motor-side connector (not shown), and is connected to the power conversion device via a case-side connector (not shown).

  As shown in FIGS. 3 and 4, the branch connection portion 11 according to the present embodiment includes a first thin wire 19 and a second thin wire that connect between the main wire conductors 27 of the main wire 17 divided at a predetermined position. It is constituted by a diameter electric wire 21. The first thin wire 19 and the second thin wire 21 each have a smaller current cross-sectional area than the main wire 17, but the total current cross-sectional area is equal to or greater than the current cross-sectional area of the main wire 17 (this embodiment). In the embodiment, each energization cross-sectional area of the first small-diameter electric wire 19 and the second small-diameter electric wire 21 is approximately half of the energization cross-sectional area of the main electric wire 17). In the present embodiment, the first thin wire 19 and the second thin wire 21 have the thin conductor 31 shown in FIG. The covering 29 covering the thin conductor 31 can be omitted because the first thin wire 19 and the second thin wire 21 are covered with an insulating protective housing 23 described later.

  The second thin wire 21 is formed longer than the first thin wire 19, and is connected to both the conductors (main wire conductor 27) of the main wire 17 together with the first thin wire 19. The thin conductor 31 of the first thin wire 19 and the second thin wire 21 is made of the same material as that of the main wire conductor 27, but a different material may be used. The small-diameter conductor 31 may be a core wire in which a plurality of strands are bundled or a single conductor (cylindrical or prismatic conductor).

  In the present embodiment, the case where the branch connection portion 11 is provided with two of the first thin wire 19 and the second thin wire 21 will be described as an example. However, the circuit breaking structure of the power cable according to the present invention is described. The branch connection part 11 may be comprised by the 3 or more small diameter electric wire. In this case, the degree of freedom in design can be increased, for example, by adjusting the breaking speed by gradually increasing the thickness from a short thin wire.

  Further, the branch connection portion 11 of the present embodiment is covered with an insulating protective housing 23. The insulation protection housing 23 is formed in a cylindrical shape and penetrates the branch connection portion 11 inward. In the present embodiment, the insulating protective housing 23 is formed in a cylindrical shape by an insulating resin material, but may be formed in a rectangular tube shape. The insulating protective housing 23 can be made of a transparent material, for example. By making the insulating protective housing 23 transparent, the broken state of the branch connection portion 11 can be easily visually recognized from the outside.

  As shown in FIG. 2, the insulation protection housing 23 has a total length L longer than the length L <b> 1 of the branch connection portion 11. For this reason, the insulation protection housing 23 can accommodate the predetermined length portion L <b> 2 of the main wire 17 connected to both ends of the branch connection portion 11.

  Within the insulating protective housing 23, the predetermined length portion L <b> 2 of the main electric wire 17 is held by the end insulating housing 25. The end insulating housing 25 holds a predetermined length portion L2 of the main electric wire 17 so as to be movable with respect to the insulating protective housing 23 in the electric wire insertion direction. Further, at both ends of the insulating protective housing 23, there are provided extra length portions 37 that allow the end insulating housing 25 to be moved by a predetermined length (for example, about 60 mm) in the electric wire insertion direction with respect to the insulating protective housing 23. .

  In the present embodiment, the end insulating housing 25 is formed in a flat columnar shape that fits into the inner periphery of the cylindrical insulating protective housing 23. The end insulating housing 25 is made of, for example, an insulating resin material. A through hole 35 through which the main electric wire 17 is penetrated is formed in the center of the column main body 33. Further, a concave groove 39 is formed on the outer periphery of the column main body 33. An O-ring 41 made of an elastic material such as rubber is attached to the concave groove 39. The O-ring 41 provides a watertight seal between the column main body 33 and the insulating protective housing 23, and is moderate in order to prevent the end insulating housing 25 and the insulating protective housing 23 from inadvertently moving relative to each other. Sliding resistance is given. When the tensile force acts on the main electric wire 17 and the branch connecting portion 11 is broken, the end insulating housing 25 can move relative to the insulating protective housing 23 together with the main electric wire 17.

  In addition, although this embodiment demonstrates the example where the branch connection part 11 is covered with the insulation protection housing 23, the circuit interruption | blocking structure of the power cable of this invention may protect the branch connection part 11 with another member. Is possible. For example, the branch connection portion 11 can be protected by a so-called protector in which a rectangular tube made of insulating resin is divided into a main body portion and a lid portion in a plane parallel to the axis. In this case, the main electric wires 17 connected to both sides of the branch connection portion 11 are held movably with respect to the protector attached to the vehicle body. Thereby, the branch connection portion 11 can be broken when a predetermined tensile force is applied to the main electric wire 17. The main electric wire 17 has the predetermined length portion L2 accommodated in the protector, so that the exposed main electric wire conductor 27 remains in the protector even after the branch connection portion 11 is broken.

  Furthermore, in the present embodiment, the main electric wires 17 and the both ends of the branch connection portion 11 are connected by the connection fitting 13. As shown in FIG. 3, the connection fitting 13 includes a thin wire side connection portion 15 and a main wire side connection portion 45 at both ends in the longitudinal direction of the connecting plate portion 43 formed in a strip shape long in the wire insertion direction. Prepare. As shown in FIG. 5, the small-diameter electric wire side connection portion 15 is formed on one end side of the connecting plate portion 43, and the thin-diameter conductors 31 of the first thin-diameter electric wire 19 and the second thin-diameter electric wire 21 are integrally crimped and connected. Is done. The main electric wire side connecting portion 45 is formed on the other end side of the connecting plate portion 43, and the main electric wire conductor 27 of the main electric wire 17 is crimped and connected.

  In addition, although this embodiment demonstrated the case where the small diameter conductor 31 and the main electric wire conductor 27 of the main electric wire 17 of the both ends of the branch connection part 11 were connected by the connection metal fitting 13, the connection metal fitting 13 was not used. The small-diameter conductors 31 on both ends of the branch connection portion 11 and the main wire conductor 27 of the main wire 17 may be directly connected. The direct connection between the branch connection portion 11 and the main electric wire 17 can be performed by, for example, ultrasonic welding, resistance welding, laser welding, or the like.

Next, the operation of the circuit breaker structure of the power cable having the above configuration will be described.
In the circuit breaker structure of the power cable according to the present embodiment, the first small-diameter wire 19 and the second small-diameter wire 21 that connect between the main wire conductors 27 of the main wire 17 divided at a predetermined position are provided side by side. Thus, the branch connection portion 11 having a current cross-sectional area equal to or larger than the current cross-sectional area of the main electric wire 17 is configured. Therefore, the branch connection portion 11 does not increase in electrical resistance, and heat generation does not become larger than other core wire portions. That is, in the circuit breaking structure of the power cable according to the present embodiment, the branch connection portion 11 having a low tensile strength can be made without reducing the current carrying capacity. Thereby, the location which breaks first can be specified, and it becomes possible to effectively protect against insulation and sparks. As described above, in the circuit breaker structure of the power cable of this embodiment, the branch connection portion 11 that is a portion that is easily disconnected is formed without using special parts or shapes.

  And each apparatus is connected to the both ends of the main electric wire 17 to which the part parted by the branch connection part 11 was connected. When a vehicle collides, the device may be deformed or the device may be moved due to an impact. In particular, when the device moves, a strong tensile force is applied to the main electric wire 17 connecting the devices.

  When the main electric wire 17 connected via the branch connection portion 11 is pulled, a tensile force is equally applied to each of the main electric wire 17 and the branch connection portion 11. In the branch connection part 11, since the length of the 1st thin wire 19 and the 2nd thin wire 21 differs, a tensile force acts on the short 1st thin wire 19 first. That is, the branch connection portion 11 receives a tensile load only by the first small-diameter electric wire 19, and the energizing cross-sectional area of the first small-diameter electric wire 19 is smaller than that of the main electric wire 17. As a result, when the main electric wire 17 is pulled, the first small-diameter electric wire 19 becomes a part that is first disconnected.

  Next, after the first thin wire 19 is broken, a tensile force acts on the long second thin wire 21. Since the energization cross-sectional area of the second thin wire 21 is smaller than the main wire 17 similarly to the first thin wire 19, the second thin wire 21 is broken.

  And when the 1st thin diameter electric wire 19 and the 2nd small diameter electric wire 21 in the branch connection part 11 are fractured | ruptured, the main electric wire 17 will be parted by the branch connection part 11. FIG. Therefore, in the circuit breaking structure of the power cable according to the present embodiment, the main electric wire 17 can be surely divided by the branch connection portion 11 when a predetermined tensile force is applied to the main electric wire 17. Therefore, it is only necessary to take insulation protection measures around the branch connection portion 11, and it is possible to effectively take measures for insulation protection and electrical safety. In addition, the desired breaking strength can be easily set by changing the thickness, length, etc. of the first thin wire 19 and the second thin wire 21 in the branch connection portion 11 while ensuring the cross-sectional area necessary for energization. Since it can be done, the degree of freedom of design is great.

  Further, in the circuit breaker structure of the power cable according to the present embodiment, a cylindrical shape that inserts the branch connection portion 11 inward and accommodates the predetermined length portion L2 of the main electric wire 17 connected to both ends of the branch connection portion 11. And an end insulating housing 25 that holds the predetermined length portion L2 of the main electric wire 17 so as to be movable in the electric wire insertion direction with respect to the insulating protective housing 23.

  Therefore, when a tensile force is applied to the main electric wire 17 in which the branch connection portion 11 is covered by the cylindrical insulating protective housing 23, the end insulating housing 25 slides relative to the insulating protective housing 23 together with the main electric wire 17. Thus, the tensile force can act on the branch connection portion 11. And the insulation protection housing 23 which covers the branch connection part 11 can perform the insulation protection at the time of the tensile fracture of a power cable reliably.

Further, in the circuit breaker structure of the power cable according to the present embodiment, the extra length portions that allow the end insulating housing 25 to move a predetermined length in the wire insertion direction with respect to the insulating protective housing 23 at both ends of the insulating protective housing 23. 37 is provided.
Therefore, the movement of the main wire 17 within a predetermined length at the time of the tensile break of the power cable does not cause the end insulating housing 25 to fall off from the extra length portion 37 of the insulating protective housing 23. The conductor portion can be prevented from coming out of the insulating protective housing 23.

  Therefore, according to the circuit breaking structure of the power cable according to the present embodiment, it is possible to provide a portion that is easily broken without securing a degree of design without using a notch shape or a brittle material.

Here, the features of the embodiment of the circuit breaker structure for a power cable according to the present invention described above will be briefly summarized below.
[1] Between the two conductors (main electric wire conductor 27) of the main electric wire (17) divided at a predetermined position, a plurality of small diameters having a smaller energizing cross-sectional area than the main electric wire (17) and different lengths. By providing the electric wires (the first small-diameter wire 19 and the second small-diameter wire 21), the branch connection portion (11) having an energization cross-sectional area larger than the energization cross-sectional area of the main electric wire (17) is provided. A circuit breaker structure for power cables.
[2] A circuit breaker structure for a power cable configured as described in [1] above,
A cylindrical insulating protective housing that passes through the branch connection portion (11) inward and accommodates a predetermined length portion (L2) of the main electric wire (17) connected to both ends of the branch connection portion (11). (23) and
An end insulating housing (25) for holding a predetermined length portion (L2) of the main electric wire (17) movably in the electric wire insertion direction with respect to the insulating protective housing (23);
A circuit breaking structure for a power cable, comprising:
[3] A circuit breaking structure for a power cable having the configuration of [2] above,
At both ends of the insulating protective housing (23), there are provided extra length portions (37) that allow the end insulating housing (25) to move a predetermined length in the wire insertion direction with respect to the insulating protective housing (23). A circuit breaker structure for a power cable.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

DESCRIPTION OF SYMBOLS 11 ... Branch connection part 13 ... Connection metal fitting 17 ... Main electric wire 19 ... 1st thin diameter electric wire (thin diameter electric wire)
21 ... Second thin wire (thin wire)
23 ... Insulating protective housing 25 ... End insulating housing 27 ... Main wire conductor

Claims (3)

  Between the two conductors of the main wire divided at a predetermined position, a plurality of small-diameter wires having a smaller current cross-sectional area than the main wire and having different lengths are provided side by side, whereby the current cross-sectional area of the main wire is increased. A circuit breaker structure for a power cable, characterized in that a branch connection portion having the above energization cross-sectional area is provided. The circuit breaker structure for a power cable according to claim 1,
A cylindrical insulating protective housing that passes through the branch connection portion inward and accommodates a predetermined length portion of the main wire connected to both ends of the branch connection portion;
An end insulating housing that holds a predetermined length of the main electric wire movably in the electric wire insertion direction with respect to the insulating protective housing;
A circuit breaking structure for a power cable, comprising: The circuit breaker structure for a power cable according to claim 2,
A circuit breaker structure for a power cable, wherein both end portions of the insulating protective housing are provided with extra length portions that allow the end insulating housing to move a predetermined length with respect to the insulating protective housing in a wire insertion direction. .

Images