JP5203292B2 - Connectors and construction machinery - Google Patents

Description

  The present invention relates to a connector and a construction machine, and more particularly to an improvement of a connector of a power cable used in a hybrid construction machine.

  As a hybrid construction machine, a generator motor and a hydraulic pump are driven by an engine, and an electric motor for an upper rotating body provided with a cab or the like is driven by electric power generated by the generator motor, and a pressure from the hydraulic pump is also driven. Construction machines are known that use oil to drive a hydraulic actuator of a work machine and a hydraulic motor of a traveling device (see, for example, Patent Documents 1 and 2).

  In such a hybrid construction machine, the generator motor and the inverter are electrically connected via a power cable, and the generator motor and the inverter are respectively connected to the power cable via a connector. Here, the electric power generated by the generator motor is transmitted to the inverter through the power cable. However, if the connector is not connected well, the power transmission is not performed reliably and the turning control is performed normally. Absent.

  For this reason, such a connector is provided with a detecting means for detecting a fitting state between the plug on the power cable side and the socket on the device (generator motor, inverter) side (for example, see Patent Document 3). The detection means described in Patent Document 3 is a configuration that measures the capacitance between a grounded shield ring that shields the outer periphery of the fitting portion and the surface of the insulating housing that covers the shield ring. When the threshold value is smaller than the preset threshold value, it can be determined that the plug and the socket are not completely fitted, and the fitted state can be detected.

WO 06/004080 pamphlet International Publication No. 06/121045 Pamphlet JP 2003-125531 A

  However, since the detection means described in Patent Document 3 uses a capacitance characteristic that changes according to the fitting state of the plug and the socket, an oscillator for applying a high-frequency voltage to the detection portion, the detection portion This requires a converter that calculates the capacitance from the value of the current flowing through it, and a detection circuit that detects the change in the calculated capacitance value and compares it with the threshold value, which complicates the configuration. is there. In addition, since the fitting state is detected by comparing the actual capacitance value with a preset threshold value, the capacitance value becomes unstable due to a change in dielectric constant or the like due to aged material deterioration of the insulating housing. Then, there is a problem that the reliability of the detection result is lowered.

  Therefore, there is a demand for a detection means having a simple structure having a mechanical contact, instead of such a capacitance type detection means. However, for example, the inside of the generator motor has a mist-like atmosphere with cooling oil that cools the stator coil, and water droplets contained in this atmosphere adhere across the contact part and the grounding part such as the shield ring. Therefore, if the water droplets are left unattached, the contact conductor components and the like may be deposited and short-circuited to the grounded portion, leading to erroneous detection. Therefore, when a mechanical contact is employed, a structure that prevents such erroneous detection is also required.

  An object of the present invention is to provide a connector that has a simple structure and can reliably prevent erroneous detection due to abnormal water, and a construction machine including the connector.

  The connector of the present invention is a connector for connecting a power cable for power transmission to a device mounted on a hybrid vehicle. The device-side socket attached to the device and the device-side socket attached to the cable And a switch that is electrically connected / disconnected by a mechanical contact provided in the device-side socket and the cable-side plug, and the device-side socket has a mechanical contact of the switch. The cable side plug has an electrically grounded plug housing, and the plug housing is provided with a contact conductor that contacts the contact terminal as a mechanical contact of the switch. The contact conductor and the plug housing face each other in the same direction. There is a body surface and a housing surface, and a step having a predetermined height is provided between the conductor surface and the housing surface along a direction orthogonal to the insertion / extraction direction of the device side socket and the cable side plug. It is characterized by being able to.

  In the connector according to the present invention, the plug housing has a metal plate to which the contact conductor is fixed and the housing surface is formed, and the housing surface of the plate and the conductor surface of the contact conductor, At least one of the surfaces is covered with an insulating coating.

  The connector according to the present invention is characterized in that the entire plate is insulated and the contact conductor is entirely insulated except for the contact area with the contact terminal.

  In the connector according to the present invention, the device is oil-cooled, and the connector is exposed to an atomized atmosphere by oil cooling for oil cooling.

  A construction machine according to the present invention includes any one of the connectors described above, a device connected via the connector, and a power cable.

  In the construction machine of the present invention, the device is any one of a generator, a motor, a generator motor, and an inverter.

  According to the connector of the present invention, the connector used to connect the power cable and a device such as a generator or an inverter has a structure having a contact conductor and a contact terminal as mechanical contacts. The switch is used as an interlock switch for detecting the insertion / extraction state of the device side socket and cable side plug. Therefore, not only the structure as a switch is simple, but also different from the conventional capacitance type, based on the converter for calculating the capacitance value and the comparison result between the capacitance value and the threshold value. A detection circuit or the like for detecting the fitting state can be eliminated, the configuration on the inverter side that is a power transmission destination, for example, can be simplified, and downsizing of the device can be greatly promoted. In addition, since it is not necessary to determine the fitting state by comparing the capacitance value with the threshold value, there is little variation in detection results and high reliability. Moreover, it is not necessary to provide signal lines or the like used for detection in the power cable, and the power cable harness work can be easily performed.

  Furthermore, in the cable-side plug, when a step is provided between the conductor surface of the contact conductor and the housing surface of the plug housing, it is difficult for water drops due to abnormal water to straddle each surface, and precipitation occurs. Can be suppressed. Accordingly, each contact is unlikely to be short-circuited to the ground side, so that erroneous detection when detecting the fitting state can be prevented.

In the present invention, by insulatingly coating at least one of the housing surface and the conductor surface, or by insulatingly coating both of them, the insulating performance can be remarkably improved and erroneous detection can be further prevented. . When the housing surface is subjected to insulation coating, since the housing surface is formed by a plate, it is only necessary to apply an insulation coating to the plate, and the coating operation can be simplified. Furthermore, since the plate is made of metal, the plug housing can sufficiently ensure strength and heat resistance, and is excellent in durability.
Here, as the insulating coating, it is possible to use a fluorine-based one having characteristics excellent in heat resistance and wear resistance and also having water repellency. By having water repellency, the water droplets themselves can be repelled and more difficult to adhere.

  In the present invention, when the generator, the motor, or the generator motor device is oil-cooled and the connector is exposed to a foggy atmosphere with cooling oil, the moisture in the atmosphere becomes water droplets, and the conductor surface and the housing surface Although it becomes an environment that is easy to straddle between, in the present invention, water droplets can be made difficult to adhere even in such an atmosphere, which is particularly beneficial.

  And in the construction machine of this invention, the effect of this invention mentioned above can be show | played by providing the said connector.

The schematic diagram which shows schematic structure of the power source used for the hybrid vehicle of one Embodiment of this invention. The perspective view which shows the housing accommodated in the housing of a generator, and its inside. The figure which shows the connector of the state from which the cable side plug removed from the apparatus side socket. The figure which looked at the connector of FIG. 3 from the other side. The schematic diagram which shows the wiring of a switch. The disassembled perspective view which shows the principal part of a cable side plug. It is sectional drawing which expands and shows the principal part of a cable side plug, and is the VII-VII sectional view taken on the line in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of a power source used in a hybrid construction machine as a hybrid vehicle of the present embodiment. In the hybrid construction machine, a generator motor 2 and a hydraulic pump 3 as devices are connected in series to the output shaft of the engine 1, and both the generator motor 2 and the hydraulic pump 3 are driven by the engine 1. Of these, the hydraulic pump 3 is commonly used in construction machines and is known, and therefore, description thereof is omitted here.

  The electric power generated by the generator motor 2 is transmitted to an inverter 5 as a device via a power cable 4 for three-phase alternating current. One end of another power cable 4 is connected to the inverter 5, and the other end of the power cable 4 is connected to an electric motor 6 as a device for driving an upper swing body of a power shovel (not shown). The inverter 5 is connected to a storage capacitor 7. The electric power generated by the generator motor 2 is stored in the capacitor 7 through the inverter 5, and is supplied from the capacitor 7 to the electric motor 6 through the inverter 5 during the turning operation.

  FIG. 2 shows a housing 10 constituting the generator motor 2. The housing 10 is fixed to a rear flange (not shown) that constitutes the crankcase of the engine 1. Although not shown in detail in the housing 10, an annular stator 11 is disposed. A large number of protrusions are provided on the inner peripheral surface of the stator 11 along the circumferential direction, and a coil is wound around each of these protrusions.

  The housing 10 has a circular opening on the hydraulic pump 3 side. This opening is closed by a disk-like closing member 12. On one surface side of the closing member 12, a rotor 13 accommodated inside the stator 11 is supported rotatably with respect to the closing member 12. The rotor 13 is accommodated in the stator 11 by closing the opening with the closing member 12, and at the same time, one end of the shaft member provided at the rotation center of the rotor 13 is spline-coupled with the output shaft of the engine 1, for example. Further, the other end of such a shaft member is provided corresponding to the central hole of the closing member 12, and is splined to the input shaft of the hydraulic pump 3 through the central hole.

  An oil reservoir 14 is provided below the housing 10 to store cooling oil that cools the coil portion of the stator 11. Cooling oil from the oil reservoir 14 is routed to an oil cooler through an external pipe, and returned from the oil cooler to the upper portion of the housing 10. The cooling oil returned from the upper part of the housing 10 to the inside of the housing 10 is splashed and atomized by the rotating rotor 13 and the flywheel rotating in the housing 10 to cool the coil portion. Thereafter, the cooling oil is dropped from the cooling portion to the oil reservoir 14.

  A terminal box 15 protruding outward is provided on the outer periphery of the housing 10. In the accommodation space in the terminal box 15, a pair of device side sockets 21 (only one is shown in FIGS. 3 and 4) constituting the connector 20 are accommodated. A cable-side plug 22 provided in the power cable 4 is fitted to the device-side socket 21 through an insertion / extraction opening 16 provided in the terminal box 15. That is, the connector 20 is constituted by the device side socket 21 and the cable side plug 22.

  Here, since the conductive wire from the coil of the stator 11 is connected to the terminal portion 23 of the device-side socket 21, the accommodation space in the terminal box 15 and the space in the housing 10 in which the stator 11 is accommodated are defined. Communicate. The accommodation space of the terminal box 15 is closed by the terminal cover 17. The terminal cover 17 is provided with a breather 18. The inside of the housing 10 is sealed so that the cooling oil does not leak, but the internal temperature rises and the internal pressure fluctuates due to proximity to the engine 1 and heat generation from the stator 11. For this reason, the breather 18 is provided in the terminal box 15 portion communicating with the inside of the housing 10 to cope with the pressure fluctuation.

The device side socket 21 will be described with reference to FIGS. However, here, the device side socket 21 of the connector 20 for connecting the power cable 4 and the generator motor 2 will be described as a representative. The same applies to the connector 20 that connects the power cable 4 and the inverter 5. Although not shown, the same applies to the connector 20 used for the power cable 4 between the electric motor 6 for turning and the inverter 5. The same plug is used for each connector 20 as will be described later.
FIG. 3 is a diagram illustrating the connector 20 in a state where the cable-side plug 22 is detached from the device-side socket 21. 4 is a view of the connector 20 as viewed from the opposite side to FIG.

  The device-side socket 21 includes a metal L-shaped bracket 24 and a resin receptacle 25 fixed to the bracket 24, and is fixed in the terminal box 15 by bolts inserted through the bracket 24. In the receptacle 25, the above-described terminal portion 23 is provided on one side with respect to a portion fixed to the bracket 24, and three holders 26 to which the cable side plug 22 is fitted are provided on the other side. A cylindrical socket contact 27 made of metal and having conductivity is embedded in the holder 26. One end of the socket contact 27 is connected to a terminal 28 at the terminal portion 23, and a conductive wire on the coil side is connected to the terminal 28.

  The device-side socket 21 is provided with a part of the interlock switch 30. As schematically shown in FIG. 5, the switch 30 includes a pair of contact terminals 31 provided on the device-side socket 21 of the connector 20 and a contact conductor 32 provided on the cable-side plug 22. The Each contact terminal 31 of the device-side socket 21 is made of an elastic leaf-spring-like metal member, and is arranged in parallel with a resin support member 33 fixed to the bracket 24, and an inverter via a signal line 34. 5 is electrically connected. In a state in which the device-side socket 21 and the cable-side plug 22 are normally fitted, the contact conductor 32 mechanically contacts both contact terminals 31 and electrically connects the contact terminals 31 to each other. In this state, each contact terminal 31 is pressed by the contact conductor 32 and elastically deformed, and the contact state between the contact terminals 31 is favorably maintained by the elastic force.

In this state, the detection pulse for detecting the fitting state output from the detection means 5A of the inverter 5 through one signal line 34 passes through one contact terminal 31, the contact conductor 32, and the other contact terminal 31, and the other. To the inverter 5 through the signal line 34. When the returned detection pulse is detected by the detection means 5A for detecting the pulse waveform provided in the inverter 5, it is determined that the connector 20 is normally fitted.
On the other hand, when the connector 20 is not completely fitted or not fitted at all, the contact conductor 32 does not come into contact with each contact terminal 31, so that the detection pulse does not return to the inverter 5, and the detection means. It is not detected at 5A. That is, since the detection pulse is not detected, it is determined that the connector 20 is not completely fitted or completely disconnected.

  When the socket contact 27 of the device side socket 21 and the pin contact 53 of the cable side plug 22 are completely fitted, the contact conductor 32 comes into contact with each contact terminal 31, and the socket contact 27 and the pin contact 53 are connected. When the fitting is slightly disengaged, the contact conductor 32 is not completely in contact with each contact terminal 31. By setting the contact positions of the members 27, 31, 32, and 53 in such a positional relationship, not only when the connector 20 is not completely fitted, but also when it is fitted incompletely. Judgment can be made with certainty.

Below, the cable side plug 22 is demonstrated based on FIG.
FIG. 6 is an exploded perspective view showing a main part of the cable-side plug 22, and FIG. 7 is a cross-sectional view showing the main part.

The cable side plug 22 is provided on the cable insertion side of the plug housing 41 with the conductive plug housing 41 through which the three cables 4A, 4B, 4C of the power cable 4 are inserted, and the cables 4A, 4B, And a clamp 42 for clamping 4C.
The plug housing 41 has a metal plate 45 that covers the opening on the front side (the side opposite to the cable insertion side). An O-ring 49 and a holder 51 provided for each of the cables 4A, 4B, and 4C are disposed in the plug housing 41, and the cables 4A, 4B, and 4C are inserted into these. The cables 4A, 4B, 4C are shielded by a braided shield.

  The holder 51 has a cylindrical shape having a flange portion 52, and the cylindrical portion is inserted into an opening hole provided in the plate 45, and the flange portion 52 is locked to the back surface of the plate 45. A conductive pin contact 53 is attached to the tip of the cables 4A, 4B, 4C inserted into the holder 51, and protrudes from a round hole provided in the holder 51.

  A seal ring 54 is provided on the outer periphery of the plug housing 41 at a position close to the plate 45. When the cable side plug 22 is inserted into the insertion / extraction opening 16 of the terminal box 15, the plug housing 41 and the insertion / extraction opening are provided. A space between the inner surfaces of the 16 seals is sealed with a seal ring 54.

  The plate 45 is fixed to the plug housing 41 by a plurality of screws 55. By fixing the plate 45, the O-ring 49 and the holder 51 are accommodated in the plug housing 41 in a pressed state. The entire surface of the plate 45 is covered with an insulating coating on both the front and back surfaces, the end surfaces of the four circumferences, the inner peripheral surface of the screw 55 insertion hole, and the inner surface of the opening hole for inserting the holder 51.

  As the insulating coating, a fluorine-based paint is used in consideration of heat resistance, wear resistance, and water repellency. In the present embodiment, 954-100 system, which is a fluorine-based paint manufactured by DuPont, is used. With this insulating coating, the plate 45 is insulated from the electrically grounded plug housing 41.

  A conductive terminal 57 is fixed to the surface of the plate 45 through an insulating plate 56 formed of glass epoxy (glass-epoxy composite material). The insulating plate 56 and the conductive terminal 57 are fixed to the plate 45 by the screw 55 described above. The material of the conductive terminal 57 is not particularly limited as long as it has conductivity, but is brass in the present embodiment.

  The conductive terminal 57 is integrally provided with a rectangular piece of contact conductor 32 that is folded back in the direction of fitting to the device-side socket 21. As described above, the contact conductor 32 is a portion that contacts each contact terminal 31 of the device-side socket 21 when the cable-side plug 22 is fitted to the device-side socket 21, and constitutes a part of the switch 30. doing.

  Such a conductive terminal 57 is insulatively coated in the same manner as the plate 45 except for the contact area 35 of the contact conductor 32 with the contact terminal 31. Therefore, the plate 45 and the conductive terminal 57 are not only insulated by the insulating plate 56 therebetween, but are also reliably insulated by the respective insulating coatings, and as a result, between the conductive terminal 57 and the plug housing 41. Is reliably insulated. The contact area 35 is not limited to the area surrounded by a two-dot chain line in the figure, and the entire surface of the contact conductor 32 that faces each contact terminal 31 is defined as a contact area 45 that is not provided with an insulating coating. Also good.

  In addition to the fact that the inner peripheral surface of the screw hole provided in the conductive terminal 57 is also coated with insulation, in the present embodiment, in order to more reliably prevent a short circuit with the plug housing 41 via the screw 55. A resin collar 58 is fitted in the screw hole, and a resin washer 59 is used between the screw 55 and the screw 55 so that the screw 55 does not contact the conductive terminal 57.

  Furthermore, in this embodiment, as shown in an enlarged view in FIG. 7, a conductor surface 321 facing the outer side (upper side in the drawing) of the contact conductor 32 provided on the conductive terminal 57 and an end surface that is a housing surface of the plate 45. The position of the conductor surface 321 is shifted inwardly (downward in the drawing) with respect to the end surface 451 so that it is not flush with the 451. Further, the end surface 571 of the conductive terminal 57 is not flush with the end surface 451 of the plate 45.

  That is, the conductor surface 321 and the end surface 451 are close to each other along the insertion / extraction direction of the device-side socket 21 and the cable-side plug 22, and face both sides outward in a direction orthogonal to the insertion / extraction direction. However, it has shifted | deviated along the direction orthogonal to the insertion / extraction direction. Accordingly, a step 61 having a predetermined height is provided between the conductive terminal 57 and the end face of the plate 45.

  Since the inside of the terminal box 15 communicates with the inside of the housing 10, a mist-like atmosphere by cooling oil is formed as in the housing 10, and the connector 20 is exposed to this atmosphere. When moisture present in the atmosphere becomes water droplets and adheres across the conductive terminal 57 and the plate 45, the material of the conductive terminal 57 and the plate 45 is deposited to form a bridge, and the detection that passes through one contact terminal 31 is detected. The pulse may cause a ground fault (short-circuited to the ground side) through the contact conductor 32, the conductive terminal 57, the bridge, the plate 45, the terminal box 15 of the generator motor 2, and the housing 10.

  However, even in the case where there is a possibility that the conductive terminal 57 is short-circuited to the ground side, in the present embodiment, since the attached water droplets are difficult to be maintained by the step 61, precipitation can be hardly caused, and the insulation performance can be improved. it can. Furthermore, when an insulating coating is applied to the surface to which water droplets adhere with water-repellent paint, the water droplets themselves can be made difficult to adhere, and even if they adhere, their surfaces are coated, which Precipitation can be reliably suppressed.

  Therefore, in the state where the cable side plug 22 is fitted in the equipment side socket 21, the contact terminal 31 can be reliably conducted by the contact conductor 32 and can be prevented from being short-circuited to the ground side. The detection pulse output to the line 34 can be reliably returned through the other signal line 34, and erroneous detection can be prevented.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the above embodiment, the generator motor 2 is oil-cooled, but is not limited to the oil-cooled type, and may be an air-cooled type such as air cooling with cooling air from a cooling fan. Even in such a case, the effect of the present invention can be exhibited against abnormal water that enters the terminal box 15. Furthermore, there may be no case where means for positively cooling the oil or air is not provided. For example, by applying the present invention, against abnormal water entering from the sealing surface between the connector 20 and the insertion / extraction opening 16. The effect of the present invention can be exhibited.

  In the above-described embodiment, both the plate 45 and the conductive terminal 57 are coated with insulation, but at least one of them may be coated with insulation, and in such a case as compared with the case where only the step 61 is provided. Thus, the insulation performance can be improved. Of course, even when only the step 61 is provided, the object of the present invention can be achieved and included in the present invention.

  In addition, when an insulating coating is applied, depending on the coating portion, even if the insulating plate 56 such as the glass epoxy or the collar 58 is omitted, sufficient insulation performance can be secured. It may be used.

  In the said embodiment, although the generator motor 2 which also has the function of the electric motor was used as a generator of this invention, the generator which does not have the function of an electric motor can also be used. When the generator motor 2 is used, the electric power stored in the capacitor 7 is transmitted to the generator motor 2 via the inverter 5, and the hydraulic motor 3 is driven as a function of the generator motor 2 as a motor. Can assist. By doing so, even when the rotational speed of the engine 1 decreases, the hydraulic pump 3 can be driven to a sufficient rotational speed.

  In the above embodiment, the present invention is applied to the connectors 20 on both sides of the power cable 4 that connects the generator motor 2 and the inverter 5, and the power cable 4 that connects the inverter 5 and the electric motor 6 for turning. The example in which the present invention is applied to the connectors 20 on both sides has been described, but the present invention may be applied to at least the connector 20 used for connecting the generator motor 2 and the power cable 4. Such a connector 20 is provided in an environment in which abnormal water is more likely to enter than other connectors 20, and the merit of applying the present invention is great. This is especially true when the generator motor 2 is oil-cooled.

  In the embodiment, the object of the present invention has been achieved by providing the step 61 between the conductor surface and the housing surface, but when at least one of the contact conductor and the plate is covered with an insulating coating. However, the object of the present invention can be achieved.

  In addition to the power shovel described in the above embodiment, the present invention can be used for other construction machines including an engine and a generator driven by the engine.

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Generator motor which is apparatus, 4 ... Power cable, 5 ... Inverter which is apparatus, 20 ... Connector, 21 ... Equipment side socket, 22 ... Cable side plug, 30 ... Switch, 31 ... Contact terminal, 32 DESCRIPTION OF SYMBOLS ... Contact conductor, 35 ... Contact area, 41 ... Plug housing, 45 ... Plate, 61 ... Step, 321 ... Conductor surface, 451 ... End surface which is a housing surface.

Claims (6)

In a connector for connecting a power cable for power transmission to equipment mounted on a hybrid vehicle,
A device-side socket attached to the device;
A cable-side plug that is attached to the cable and is inserted into and removed from the device-side socket;
A switch that is electrically interrupted by a mechanical contact provided in the device side socket and the cable side plug;
The device side socket is provided with a contact terminal as a mechanical contact of the switch, and the cable side plug has an electrically grounded plug housing,
The plug housing is provided with a contact conductor that contacts the contact terminal as a mechanical contact of the switch,
The contact conductor and the plug housing each have a conductor surface and a housing surface facing in the same direction,
The connector is characterized in that a step having a predetermined height is provided between the conductor surface and the housing surface along a direction orthogonal to the insertion / extraction direction of the device side socket and the cable side plug. The connector according to claim 1,
The plug housing has a metal plate to which the contact conductor is fixed and the housing surface is formed,
At least one of the housing surface of the plate and the conductor surface of the contact conductor is covered with an insulating coating. The connector according to claim 2,
The entire plate is insulation coated,
The connector, wherein the contact conductor is entirely coated with an insulating coating except for a contact area with the contact terminal. The connector according to any one of claims 1 to 3,
The equipment is oil cooled,
The connector is exposed to a mist atmosphere by oil cooling for oil cooling. A connector according to any one of claims 1 to 4,
A construction machine comprising: a device connected via the connector; and a power cable. The construction machine according to claim 5,
The construction machine is any one of a generator, a motor, a generator motor, and an inverter.

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