power plug

Abstract

The present application provides a power plug which can remove or reduce noise with a simple structure without increasing the size or weight of a charging cable or the like. First metal plates between the first pin portion and the power line and second metal plates between the ground terminal portion and the ground line are arranged in parallel to each other, and a dielectric is sandwiched between the first metal plates and the second metal plates to form a noise filter. Since the capacitor is formed by arranging the metal plates between the pin portion or the ground terminal portion and the cable connected thereto, the overall structure can be miniaturized and lightened.

Description

Technical Field

[0001] This invention relates to a power plug that is inserted into a power socket, and more particularly to a power plug for use in charging cables and the like for charging electric vehicles. Background Technology

[0002] Electric vehicles, such as battery electric vehicles (BEVs) or plug-in hybrid electric vehicles (PHEVs), supply power to their motors for driving from an onboard battery. Since the driving range of an electric vehicle is limited by the remaining charge (SOC) of the battery, efforts are being made to increase battery capacity to extend the driving range on a single charge. Furthermore, increasing the power output during charging is being researched to shorten charging time. As a technical challenge in charging electric vehicles, issues such as heat generation or noise caused by contact resistance or tracking between the plug and socket are known. Regarding heat generation, a thermistor is used to detect the temperature and control the current based on the detected signal. In a charging cable equipped with a controller, a thermistor is placed in the power plug, and its detection signal is sent to the controller to control the charging current. In this case, it is desirable for the thermistor to accurately detect the temperature of the power plug; therefore, in the power cable described in Patent Document 1, the power plug is configured such that, when the power plug is connected to the power socket, the thermistor is positioned higher than the plug pins.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2013-187112 Summary of the Invention

[0004] The power cable described in Patent Document 1 has a structure to cope with heat generation, but it cannot reduce the noise that inevitably occurs during charging. Noise generated during charging is known to include normal mode noise and common mode noise. Among these, common mode noise has a complex transmission mechanism, making it difficult to counteract, but it is believed that it can be removed or reduced by so-called shielding. However, since electric vehicle charging cables are mostly operated by ordinary people at ordinary homes or street charging stations, they are required to be lightweight, easy to handle, and inexpensive. Therefore, in charging cables that incorporate shielding as a noise countermeasure, there is a disadvantage: the overall charging cable becomes thicker and heavier due to the addition of shielding.

[0005] This invention was made in view of the above-mentioned technical problems, and its purpose is to provide a power plug that can eliminate or reduce noise with a simple structure without making the charging cable large or heavy.

[0006] To achieve the above objectives, the present invention provides a power plug comprising: at least a pair of pins, a first pin portion and a second pin portion; a grounding terminal portion for grounding; a first cable connected to the first pin portion; a second cable connected to the second pin portion; and a third cable connected to the grounding terminal portion. The power plug is characterized in that a first metal plate and a second metal plate are arranged parallel to each other, the first metal plate being located between and connected to any one of the first pin portion, the second pin portion, and the grounding terminal portion. The first cable, the second cable, and the third cable are connected to each other in the first pin portion, the second pin portion, and the grounding terminal portion, and the first cable, the second cable, and the third cable are connected to each other in the first pin portion, the second pin portion, and the grounding terminal portion. A dielectric is sandwiched between the first metal plate and the second metal plate, and a noise filter is formed by the first metal plate, the second metal plate, and the dielectric.

[0007] In this invention, it may further include: an electrically insulating housing that holds the first pin, the second pin, and the grounding terminal in a state that protrudes towards the front end; the noise filter is housed inside the housing; inside the housing, the first pin is connected to the first cable, the second pin is connected to the second cable, and the grounding terminal is connected to the third cable.

[0008] In this invention, the first metal plate may be located between the first pin and the first cable, and the second metal plate may be located between the second pin and the second cable, with a thermistor mounted on either the first metal plate or the second metal plate.

[0009] Invention Effects

[0010] According to the present invention, a capacitor is formed by the first and second metal plates and the dielectric therebetween, which functions as a filter to remove or reduce noise. These metal plates are disposed between any of the pins and the grounding terminal and the corresponding cable to form a noise filter. Therefore, the noise filter is a structure built into the power plug, resulting in the miniaturization or weight reduction of the power plug, and consequently, making the charging cable with the power plug easier to operate.

[0011] Furthermore, if the structure is configured such that the metal plates are connected to the first and second pins respectively to form a noise filter, and a thermistor is mounted on one of the metal plates, the temperature difference between the pins will be reduced through the heat conduction of the dielectric. As a result, the temperature can be accurately or precisely detected with one thermistor. Consequently, the number of thermistors and other components required can be reduced, thereby miniaturizing or lightening the power plug. Attached Figure Description

[0012] Figure 1 This is a side view showing an example of a charging cable to which the present invention can be applied.

[0013] Figure 2 This is the front view of the power plug.

[0014] Figure 3 It is a schematic cross-sectional view used to show the internal structure of a power plug.

[0015] Figure 4 It is along Figure 1 A sectional view cut along line IV-IV.

[0016] Figure 5 This represents another example of the invention, and... Figure 3 The same schematic sectional view.

[0017] Figure 6 It means in Figure 5 The diagram shows a schematic cross-sectional view of the structure with an added thermistor. Detailed Implementation

[0018] Next, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, the embodiments described below are merely examples of implementing the present invention and are not intended to limit the invention.

[0019] Figure 1 The diagram shows a charging cable 1 to which the present invention can be applied. The charging cable 1 shown here is a "mode 2" cable, with a power plug 3 at one end of the cable portion 2 and a charging connector 4 at the opposite end. A controller 5 is further provided in the middle of the cable portion 2. The power plug 3 is configured to be inserted into the power socket of a charger (not shown) for connection, as... Figure 2 As shown in the front view, the plug 3 has two prongs, 6 and 7, for heating and cooling, and a grounding terminal 8 for grounding. The power plug 3 is a structure in which the entire assembly is housed in a housing 9 made of an electrically insulating material such as synthetic resin. The prongs 6 and 7 and the grounding terminal 8 are held by the housing 9 in a state that protrudes from the housing 9 toward the front end.

[0020] Figure 3The diagram shows a schematic cross-sectional view illustrating the internal structure of the power plug 3. The cross-section shown is a cut along a surface passing through a pin portion 7 (corresponding to the first pin portion) and a grounding terminal portion 8. The pin portion 7, the grounding terminal portion 8, and the surface corresponding to the first pin portion... Figure 3 The second pin portion 6, which is not present in the design, is embedded (molded) in the middle of its length direction into the resin or other material constituting the housing 9 and is held within the housing 9. Its rear end is connected to metal plates 10 and 11 inside the housing 9.

[0021] The metal plates 10 and 11 are, in essence, conductive plate-shaped components, and can be solid plate-shaped metals such as busbars. Furthermore, in principle, they can also be components whose surface is covered with a highly conductive material. These metal plates 10 and 11 are arranged parallel to each other at predetermined intervals and fixed inside the housing 9. A suitable dielectric 12 is sandwiched between the metal plates 10 and 11. The dielectric can be a known suitable material, such as ceramic, synthetic resin, or mica, and a solid dielectric is particularly preferred. Therefore, these metal plates 10 and 11 and the dielectric 12 constitute a capacitor and become a noise filter 13.

[0022] A power line L, equivalent to the first cable, is connected to the metal plate 10 that is conductive to the pin portion 7, and a grounding wire G, equivalent to the third cable, is connected to the metal plate 11 that is conductive to the grounding terminal portion 8. This connection can be made by a suitable method, such as crimping, welding, brazing, screw fixing, etc. Therefore, the metal plate 10, equivalent to the first metal plate, is positioned between the pin portion 7 and the power line L, making the pin portion 7 electrically conductive to the power line L. Similarly, the metal plate 11, equivalent to the second metal plate, is positioned between the grounding terminal portion 8 and the grounding wire G, making the grounding terminal portion 8 electrically conductive to the grounding wire G. In addition, although in Figure 3 The other pins 6, which are not shown in the diagram, are electrically connected to the power line N, which corresponds to the second pin. Furthermore, the power lines L, N, and grounding wire G are together sheathed and become part of the cable section 2, and are connected to the aforementioned controller 5. Additionally, inside the cable section 2, there is a signal line CPLT that transmits signals used for control (control wire signals: CPLT signals). This configuration is schematically shown in a cross-sectional view. Figure 4 middle.

[0023] In the power plug 3 described above according to the present invention, a portion of the signal returned through the ground or housing 9 becomes noise (common-mode noise). However, the charge in the capacitor changes due to this returned signal, thus removing or reducing the noise. In particular, in the power plug 3, a capacitor composed of metal plates 10 and 11 and a dielectric 12 is formed between the plug portion 7 or the power line L and the ground terminal portion 8 or the ground wire G, thus removing or reducing common-mode noise. Furthermore, the power plug 3 according to the present invention has a structure in which metal plates 10 and 11 are placed between the plug portion 7 or the ground terminal portion 8 and the respectively conductive power line L or ground wire G, and the dielectric 12 is held by these metal plates 10 and 11. Therefore, it can be designed as a small and lightweight power plug 3 with the capacitor housed inside the housing 9. Furthermore, according to the power plug 3 of the present invention, a charging cable with low noise and easy handling can be obtained.

[0024] Furthermore, the power plug 3 of the present invention can also be configured to correspond to constant-mode noise. This is illustrated in... Figure 5 In, with Figure 3 The same schematic cross-sectional view is shown. In Figure 5 In the structure shown, for example, another metal plate 14 is arranged parallel to the metal plate 10 connected to the cold-side pin portion 7, and this metal plate 14 is connected, for example, to the hot-side pin portion 6. This other metal plate 14 can have the same structure as the aforementioned metal plates 10 and 11. Furthermore, a dielectric 15 is sandwiched between these metal plates 10 and 14 to form a capacitor. That is, a noise filter 16 is provided between each pin portion 6 and 7 or between the electric field line L and another electric field line N. Other structures are the same as those described above.

[0025] exist Figure 5 In the example shown, a structure with capacitors placed between the power lines allows noise generated by the power source to be bypassed, thereby removing or reducing noise (normal-mode noise). Furthermore, with... Figure 3 Similarly, the example shown can be configured as a small and lightweight power plug 3 with a capacitor or the like housed inside the housing 9.

[0026] The power plug 3 of the present invention has the same structure for preventing overheating as conventional power plugs. Figure 6 An example is shown with a thermistor 17 configured to limit the current according to temperature. Figure 6 This is a schematic representation of the above. Figure 5 The cross-sectional view of an example of a structure with an additional thermistor 17 shown shows that the thermistor 17 is disposed on the back side (the side opposite to the dielectric 15 side) of a metal plate (e.g., a metal plate 10 connected to the cold-side pin 7), via a fixing portion 18 on a sheet made of an electrically insulating material. This thermistor 17 is connected to the aforementioned controller 5.

[0027] In the event of heat generation due to contact resistance or leakage during charging, heat from one pin 7 is transferred to the thermistor 17 via the metal plate 10 connected to it, and its temperature is detected by the thermistor 17 as an increase in its resistance value. Furthermore, heat from the other pin 6 is transferred to the metal plate 14 connected to it, and then via the dielectric 15 and the metal plate 10 to the thermistor 17. That is, since the dielectric 15 performs heat conduction, the thermistor 17 receives heat from the other pin 6, detects its temperature, and outputs a detection signal as an increase in its resistance value. In other words, in Figure 6 In the structure shown, even though there are two potentially hot-heating pins 6 and 7, a capacitor is placed between them, and a thermistor 17 is mounted on a metal plate constituting the capacitor. Therefore, the thermistor 17, which serves as a temperature sensing element, can be a single unit. Thus, in the power plug 3 according to the present invention, the required structural components can be reduced, leading to miniaturization or weight reduction, and consequently, lower costs.

[0028] Furthermore, the present invention is not limited to the specific examples described above; the charging cable to which the present invention can be applied can be a cable of "Mode 1" or a cable of "Mode 3". Moreover, in the present invention, each pin or grounding terminal only needs to be electrically connected to the metal plate; therefore, each pin or grounding terminal and the metal plate can be integrally formed as a single component.

[0029] Symbol Explanation

[0030] 1-Charging cable, 2-Cable section, 3-Power plug, 4-Charging connector, 5-Controller, 6, 7-Pin section, 8-Grounding terminal section, 9-Housing, 10, 11, 14-Metal plate, 12, 15-Dielectric, 13, 16-Noise filter, 17-Thermistor, 18-Fixing section, CPLT-Signal line, G-Grounding line, L, N-Power line.

Claims

1. A power plug comprising: at least a pair of pins, a first pin portion and a second pin portion; a grounding terminal portion for grounding; a first cable connected to the first pin portion; a second cable connected to the second pin portion; and a third cable connected to the grounding terminal portion, characterized in that... The first metal plate and the second metal plate are arranged parallel to each other. The first metal plate is located between any one of the first pin portion, the second pin portion, and the grounding terminal portion, and between any one of the first cable, the second cable, and the third cable that are connected to any one of the first pin portion, the second pin portion, and the grounding terminal portion. The second metal plate is located between any of the first pin portion, the second pin portion, and the grounding terminal portion, and between any of the first cable, the second cable, and the third cable that are connected to any of the first pin portion, the second pin portion, and the grounding terminal portion, and a dielectric is sandwiched between the first metal plate and the second metal plate. A noise filter is formed by the first metal plate, the second metal plate, and the dielectric.

2. The power plug according to claim 1, characterized in that, It also has: An electrically insulating housing that holds the first pin, the second pin, and the grounding terminal in a forward-protruding position. The noise filter is housed inside the housing. Inside the housing, the first pin is connected to the first cable, the second pin is connected to the second cable, and the grounding terminal is connected to the third cable.

3. The power plug according to claim 1 or 2, characterized in that, The first metal plate is located between the first pin and the first cable, and the second metal plate is located between the second pin and the second cable. A thermistor is installed on either the first metal plate or the second metal plate.

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