TW201735474A - USB plug - Google Patents

Abstract

To prevent a malfunction caused by static electricity and the like, and to protect a contact from excessive current. Provided is a USB plug that comprises: a plastic cover part 51 that connects a lead line 60; a plug part 52 that is fixed to the cover part 51; an external connection contact 53 that is provided in the plug part 52; and a temperature switch 54 that is connected between the external connection contact 53 and the lead line 60. The temperature switch 54 is a breaker 30 that switches a contact point to an off state upon detecting a temperature higher than a set temperature. The breaker 30 is provided with: an outer case 1; a fixed contact metal plate 4 that has a fixed contact 5 and that is obtained by being fixed to the outer case 1; a movable contact metal plate 6 that has in an elastic arm 6A a movable contact 7 opposing the fixed contact 5 and that is obtained by being fixed to the outer case 1 so that the elastic arm 6A can move; a bimetal 8 that separates the movable contact 7 from the fixed contact 5 by pressing the elastic arm 6A of the movable contact metal plate 6; and a PTC heater 9 that heats the bimetal 8.

Description

USB plug

The present invention relates to a USB plug that is detachably connected to a USB connector of an electronic device such as a tablet, and more particularly to a USB plug that is most suitable for supplying power to an electronic device.

An electronic device such as a tablet having a USB connector is connected to an external connection device such as an AC adapter via a USB plug. The USB plug that supplies power to the electronic device generates heat when it is connected to the electronic device. This is because if the contact resistance of the USB connector and the USB plug increases, the Joule heat is generated in proportion to the square of the current and the contact resistance. The USB connector has a small contact point with respect to the rated current, which is also a factor that causes an increase in contact resistance. The contact pressure of the smaller contact is also small, which is also a factor that causes an increase in contact resistance. Further, since the micro USB has a small contact point, it is more difficult to stably connect the smaller contact resistance. Since the smaller USB connector has a smaller heat dissipation area, the temperature rise relative to the amount of heat generation becomes larger. The rise in the temperature of the USB connector is a cause of various high temperature damage to the electronic device. In order to avoid this disadvantage, a USB plug has been developed which detects the temperature, switches the FET to the off state, and cuts off the current.

As shown in FIG. 13, the USB plug has a resin cover portion 91 inserted into one end of the cable 10, a plug portion 92 projecting from the front end of the cover portion 91, and a circuit board 95 disposed in the cover portion 91. A current cutoff IC 93 for a thermal protection circuit that cuts off current when the temperature exceeds the set temperature is mounted on the circuit board 95. The current cutoff IC 93 includes a temperature detecting circuit such as a thermistor that detects temperature, and an FET that performs on/off control by the temperature detecting circuit. The current cutoff IC 93 is configured to switch the FET to the off state and cut off the power supply line when the detected temperature exceeds the set temperature. Further, the USB connector is provided with a metal bonding member 97 that thermally couples the heat conducting portion of the thermal protection circuit with the metal case 96 of the plug portion 52 and the thermal protection circuit temperature switch IC 94 of the thermal protection circuit to heat the plug portion 52. Conducted efficiently to the thermal protection circuit. Although the above USB plug can detect the temperature and cut off the current, the USB connector mounts a complicated electronic component such as a current interrupting IC and an external component on a plurality of circuit boards, so that the cost of the component is high, and The assembly steps are also complicated, so there is a disadvantage that the manufacturing cost is increased. Further, since semiconductor elements such as ICs and FETs are used to cut off currents at the detection temperature, electrostatic damage is likely to occur, and the overcurrent does not cut off the current, so that the contact of the USB plug cannot be prevented. The shortcomings of over current. The present invention has been developed for the purpose of solving the above disadvantages. An important object of the present invention is to provide a USB plug which can be mass-produced at low cost, can prevent malfunction caused by static electricity or the like, and can achieve excellent durability, thereby preventing the contact from being overcurrent. [Means for Solving the Problems and Effects of the Invention] The USB plug of the present invention includes a plastic cover portion 51 that connects one end of the lead wire 60, and a plug portion 52 that is fixed to the cover portion 51 and that is detachably connected to the external connection. The machine is a USB connector of an electronic device; an external connection contact 53 is provided at the plug portion 52; and a temperature switch 54 is connected between the external connection contact 53 and the lead 60. The temperature switch 54 detects the circuit breaker 30 that switches the contact to the off state by detecting a temperature higher than the set temperature. The circuit breaker 30 includes: a housing 1; a fixed contact metal plate 4 fixed to the outer casing 1 and having a fixed contact 5; and a movable contact metal plate 6 having a fixed contact 5 with the fixed contact metal plate 4 The elastic arm 6A of the movable contact 7 is disposed at a position opposite thereto, and the fixing portion 6B of one end of the elastic arm 6A is fixed to the outer casing 1 in such a manner that the elastic arm 6A is movable; the bimetal 8 presses the movable contact a fixing portion 6B at one end of 6A separates the movable contact 7 from the fixed contact 5; and a PTC heater 9 located at a position to heat the bimetal 8 and connected to the movable contact metal plate 6 and the fixed contact metal Board 4. The elastic arm 6A of the movable contact metal plate 6 has the elasticity of the movable contact 7 contacting the fixed contact 5 by the elasticity of the second metal piece 8 without being pressed by the bimetal 8, and the bimetal 8 is disposed on Between the elastic arm 6A and the PTC heater 9; in the non-deformed state in which the bimetal 8 is not thermally deformed, the movable contact 7 is brought into contact with the fixed contact 5 by the elasticity of the elastic arm 6; In the reverse bending state of the thermal deformation of the bimetal 8, the bimetal 8 presses the elastic arm 6A to separate the movable contact 7 from the fixed contact 5, and is turned off, and in the off state, the PTC heater 9 The bimetal 8 is heated and kept in an open state. The above USB plug is characterized in that it can be mass-produced inexpensively by a small number of parts, can prevent malfunction caused by static electricity or the like, and can achieve excellent durability, thereby preventing the contact from being overcurrent. This is because the circuit breaker is used as the temperature switch of the above USB plug, which uses the bimetal to invert the detected temperature to drive the movable contact, and when it is higher than the set temperature, the current is cut off. Furthermore, since the above USB connector is provided with a PTC heater for heating the bimetal in the built-in circuit breaker, and the PTC heater is connected to the movable contact metal plate and the fixed contact metal plate, the movable contact is In the disconnected state in which the fixed contacts are separated, a weak current flows in the PTC heater via the load. The weak current of the PTC heater heats the PTC heater. The heated PTC heater heats the bimetal while maintaining the movable contact in the open state. Therefore, after the temperature rises and the circuit breaker is switched to the off state, the PTC heater automatically maintains the off state. Therefore, after the temperature rises, until the USB plug is pulled out from the USB connector and the load is released and reset, the current can be continuously cut off and used safely. However, although a weak current flows through the PTC heater through the load in the off state, since the current is extremely small, the temperature does not rise due to the current. The USB plug of the present invention may have a configuration in which a circuit board 55 disposed on the lid portion 51 is provided, and the circuit breaker 30 is fixed to the circuit board 55. Since the above USB plug is attached to the cover by fixing the circuit breaker to the circuit board, it has a feature that the circuit breaker can be stably fixed inside. The USB plug of the present invention may be composed of an inner plastic piece 51A which is partially embedded in a portion of the plug portion 52, the circuit substrate 55, the circuit breaker 30 and the lead wire 60 in the plastic cover portion 51; 51B, which is embedded with the inner plastic material 51A. The above USB plug has a feature that it can prevent displacement of constituent parts on the one hand and can be mass-produced at low cost. The reason for this is that the outer plastic material can be injection molded and molded, and the plastic material on the outer side of the injection molding can be insert-molded to insert the inner plastic material into a fixed position. Since one part of the plug portion, the circuit breaker, the circuit board, and the end portion of the lead wire are placed in the fixed position in the inner plastic body, even if the inner plastic material is temporarily fixed to the metal mold forming chamber of the molded outer plastic material, the outer side is When the plastic material is injection molded and molded, the displacement of the constituent parts due to the high injection pressure of the molten resin at the time of molding does not occur. Therefore, the USB plug has a feature that the plug portion, the circuit board, and the lead can be disposed at a fixed position on the one hand, and can be mass-produced at low cost. The above USB plug can be configured such that the inner plastic piece 51A of the USB plug is made of a hot-melt plastic material, and the inner plastic piece 51A is insert-molded and fixed to the outer plastic piece 51B. The above USB plug is formed of a hot-melt plastic material to form the inner plastic material, so that the inner plastic material can be formed at a lower molding temperature and pressure than the outer plastic material. Therefore, it is characterized in that the plug portion, the circuit board and the lead wires are disposed without displacement, and are buried in a fixed position of the inner plastic material. The USB plug of the present invention can be provided with a metal exposed plate portion 4A exposed on the surface of the circuit breaker 30, and the exposed plate portion 4A is buried in the inner plastic body 51A in a sealed state. Since the USB plug is thermally coupled to the exposed plastic part exposed on the surface of the circuit breaker, the thermal energy is efficiently transferred to the circuit breaker via the inner plastic material. Therefore, the circuit breaker can be sensitively operated to cut off the current when the temperature rises. The USB plug of the present invention is provided with a metal cylinder inserted into the electronic device in the plug portion 52; a heat conducting plate 58 connected to the metal can 56 in a thermally coupled state is embedded in the cover portion 51, and the heat conducting plate 58 is thermally coupled to the open circuit. The outer casing 1 of the device 30 can thermally couple the circuit breaker 30 to the metal can 56 via a thermally conductive plate. The above USB plug is characterized in that it can sensitively detect the temperature rise of the plug portion and cut off the current. The reason for this is that since the circuit breaker is thermally coupled to the metal barrel of the plug portion via the heat conducting plate, the thermal energy of the metal tube is conducted to the circuit breaker via the heat conducting plate. The USB plug of the present invention can be provided with a metal-made exposed plate portion 4A exposed to the surface of the circuit breaker 30, and the heat-conductive plate 58 can be disposed in the thermally exposed state to the exposed plate portion 4A. The USB plug described above further has the feature of sensitively detecting the temperature rise of the plug portion and cutting off the current. This is because the exposed plate portion provided in the circuit breaker is thermally coupled to the metal tube of the plug portion via the heat conducting plate, so that the thermal energy of the metal tube can be conducted to the exposed plate portion of the circuit breaker via the heat conducting plate. The USB plug of the present invention can set the resistance of either or both of the movable contact metal plate of the circuit breaker and the fixed contact metal plate to the bimetal by the Joule heat of the overcurrent which is larger than the set current. The resistance value is switched to the off state by heating. The above USB plug has the feature of protecting the external connection contact 53 from overcurrent. The reason is that if an overcurrent that is larger than the set current flows in the external connection 53 , any one or both of the movable contact metal plate and the fixed contact metal plate may generate heat to heat the bimetal, thereby making it movable. The contact metal plate is reversed and switched to the off state. The USB plug of the present invention can be set as a micro USB connector.

Embodiments of the present invention will be described below based on the drawings. However, the embodiments shown below are merely illustrative of USB plugs for embodying the technical idea of the present invention, and the USB plug of the present invention is not specifically configured or constructed as follows. Furthermore, the description is not intended to be a component of the embodiments disclosed herein. The USB plug shown in FIG. 1 includes a plastic cover portion 51 that is embedded to connect one end of the lead wire 60, and a plug portion 52 that is fixed to the cover portion 51 and that is detachably connected to an external connection device, that is, an electronic device. A USB connector of the machine; an external connection contact 53 provided at the plug portion 52 to be connected to the contact of the electronic device; and a temperature switch 54 connected between the external connection contact 53 and the lead 60. The temperature switch 54 performs temperature detection, and if the detected temperature is higher than the set temperature, the current is cut off. The temperature switch 54 is a circuit breaker 30 that is fixed to the circuit board 55 and is embedded in a fixed position in the lid portion 51 via the circuit board 55. The lid portion 51 includes an inner plastic piece 51A and an outer side plastic piece 51B. The inner plastic piece 51A is embedded with a portion of the rear end portion of the plug portion 52, the circuit board 55, the circuit breaker 30, and the lead wire 60. The outer plastic piece 51B is provided with an inner plastic piece 51A, and is covered with the outer side of the inner plastic piece 51A to shape the outer shape into a specific shape. The inner plastic piece 51A is a hot-melt type plastic which can be molded at a low temperature and a low pressure. The hot-melt plastic can be melted at a low temperature and can be molded into a molding chamber at a low pressure of, for example, 10 bar or less. The hot-melt type plastic can be a polyamide type, a polyurethane type, a polyester type, an EVA type, an anthraquinone type, or a mixture of these various types of plastics. The plug portion 52, the circuit board 55, and the lead wire 60 are insert-molded into the inner plastic material 51A and are embedded in a fixed position. The plug portion 52, the circuit board 55, and the lead wires 60 are temporarily fixed to the mold forming chamber of the molded inner plastic material 51A in a state of being connected to each other, and are insert-molded and embedded in the inner plastic material 51A. The inner plastic material 51A formed of a hot-melt plastic is melted at a low temperature and injected into the molding chamber. Further, the inner plastic material 51A is molded by injecting it into the molding chamber at a low pressure. When the hot-melt plastic injected into the molding chamber is injected into the molding chamber in a molten state, it is possible to prevent displacement of the plug portion 52, the circuit substrate 55, or the lead wire 60 temporarily fixed to the molding chamber, or to prevent thermal damage and insert the insert. forming. Since the inner plastic piece 51A formed by the metal mold is formed into a shape in the molding chamber, the outer plastic piece 51B can be formed by temporarily fixing it to a fixed position of the metal mold of the outer plastic part 51B. Therefore, there is a feature that the outer plastic piece 51B can be formed simply and efficiently. However, the inner plastic material 51A does not necessarily have to be formed by a metal mold to form its outer shape into a constant shape. This is because the inner plastic piece 51A can be embedded in the outer plastic piece 51B, and the outer shape of the cover portion 51 can be formed into a constant shape. For the inner plastic material 51A which is not formed by a metal mold, for example, a urethane-based adhesive or the like can be used. The inner plastic material 51A is applied to the surface of the plug portion 52, the circuit board 55, and the lead 60 which are connected to each other by an uncured adhesive which is not cured, and is cured to become the inner plastic material 51A. The circuit board 55 and the circuit breaker 30 are embedded in the inner plastic material 51A in a state of being sealed, and the heat conduction with the inner plastic material 51A is in a good state. The outer plastic piece 51B is formed by insert molding the inner plastic piece 51A and embedding it in a fixed position to mold the lid portion 51. The insert molded inner plastic piece 51A is temporarily fixed to the metal mold forming chamber where the outer plastic piece 51B is to be formed. The outer plastic piece 51B is molded by injecting molten resin into the metal mold forming chamber in which the inner plastic material 51A is temporarily fixed. The outer plastic piece 51B is molded by injection molding. The temperature at which the injection molding system is injected into the molten state of the molding chamber is high and the injection pressure is also high, but the displacement of the circuit board 55 or the lead 60 is not caused. This is because the circuit board 55 and the lead wires 60 are embedded in the inner plastic material 51 and placed at a fixed position. Therefore, the circuit board 55 and the lead wire 60 are embedded in the inner plastic material 51A, and the inner plastic material 51A is insert-molded into the outer plastic material 51B by injection molding, so that the lid portion 51 can be mass-produced efficiently, and the built-in portion can be prevented. Component displacement. Further, since the inner plastic material 51A is insert-molded and embedded by the high injection pressure of the molded outer plastic material 51B, the surface of the circuit board 55 and the circuit breaker 30 can be buried in the inner plastic material 51A. And make the heat conduction state a feature of the ideal state. The plug portion 52 is provided with an insulating substrate 57 inside the metal can 56, and an external connection contact 53 is provided on the insulating substrate 57. The metal cylinder 56 fixes the rear end portion to the lid portion 51. The external connection contact 53 is connected to the contact of the electronic device in a state in which the metal can 56 is inserted into the USB connector of the electronic device. The circuit board 55 is provided on the surface of the insulating substrate 57 including the glass fiber-reinforced epoxy resin, and is provided with a conductive wiring. The circuit board 55 is fixed with a circuit breaker 30 on its surface. The circuit breaker 30 is fixed to the surface of the circuit board 55 by a method such as reflow soldering. Further, the circuit board 55 is provided with a connection terminal connected to the external connection contact 53 of the plug portion 52 and a connection terminal of the connection lead 60, and the connection terminals are soldered to connect the external connection contact 53 with the lead 60. The circuit board 55 is connected to the metal cylinder 56 by welding the external connection contact 53 to the connection terminal, or is connected to the metal cylinder 56 by an embedded structure (not shown). The circuit breaker 30 shown in FIG. 2 to FIG. 7 is provided with: a casing 1; a fixed contact metal plate 4 having a fixed contact 5 disposed inside the casing 1; and a movable contact metal plate 6 having The fixed contact 5 of the fixed contact metal plate 4 is disposed at a position opposite to the elastic arm 6A of the movable contact 7. Further, the circuit breaker 30 is disposed between the movable contact metal plate 6 and the case bottom portion 1T by deforming the movable contact metal plate 6 from the on-off to the disconnected bimetal 8 at the ambient temperature. Further, it also has a PTC heater 9 that heats the bimetal 8 and automatically holds it. The elastic arm 6A of the movable contact metal plate 6 has elasticity which makes the movable contact 7 contact the fixed contact 5 with its own elasticity in a state where it is not pressed by the bimetal 8. The bimetal 8 is disposed between the elastic arm 6A and the PTC heater 9. The bimetal 8 is in a non-deformed state in which no thermal deformation occurs in a state lower than a set temperature. In this state, the bimetal 8 does not press the elastic arm 6A, and the circuit breaker 30 is brought into contact with the fixed contact 5 by the elasticity of the elastic arm 6A to be in an ON state. When the temperature of the circuit breaker 30 is higher than the set temperature, the bimetal 8 is thermally deformed and inverted, and is in an inverted bending state. The bimetal 8 in the reversed state is brought into contact with the PTC heater 9 of the bottom portion 1T of the casing, and the elastic arm 6A is pushed up by the outer peripheral portion of the both ends, and the movable contact 7 is separated from the fixed contact 5 to be switched. Is disconnected. The bimetal 8 is formed by laminating metals having different thermal expansion coefficients, so that thermal deformation can occur when the temperature rises. The bimetal 8 has a quadrangular shape and is curved in a convex shape toward the center. The bimetal 8 is located between the elastic arm 6A and the bottom 1T of the casing. In the figure, it is located between the elastic arm 6A and the PTC heater 9. If the set temperature is reached, it is thermally deformed and reversed to become a reverse bending state. . The bimetal 8 is deformable from a non-deformed state to a reversely bent state, and is disposed in the bimetal receiving portion 28 provided in the outer casing 1 in order to prevent displacement. As shown in the plan view of FIG. 7, the outer casing 1 is provided with a bimetal receiving portion 28 in which a square bimetal 8 is placed at a fixed position. The outer casing 1 is provided with an outer peripheral wall 10 around the bimetal 8, and the inner side of the outer peripheral wall 10 is a bimetal receiving portion 28. The bimetal accommodating portion 28 surrounded by the outer peripheral wall 10 has a shape slightly larger than that of the bimetal 8 and is capable of deforming the bimetal 8 into a non-deformed state and a reversely bent state. Configured in a fixed position. The movable contact metal plate 6 is a metal plate that is elastically deformed, and has a fixing portion 6B fixed to the outer casing 1 and an elastic arm 6A provided with a movable contact 7 at the front end. As shown in FIGS. 3 and 4, the movable contact metal plate 6 fixes the fixing portion 6B to the outer casing 1, and the elastic arm 6A on the distal end side is disposed in the housing space 20 provided in the outer casing 1. The movable contact metal plate 6 fixes the fixing portion 6B to the upper portion of the second outer wall 11B provided on the outer casing 1. The movable contact metal plate 6 protrudes from the outer casing 1 on the outer side of the fixed portion 6B, and the protruding piece 6X serves as the connection terminal 41 on the movable side. The movable contact metal plate 6 is an elastically deformable metal plate which is disposed on the elastic arm 6A disposed in the housing space 20 or the entirety thereof. Further, the movable contact metal plate 6 is attached to the front end portion of the elastic arm 6A and faces the fixed contact 5, and the movable contact 7 is provided. The movable contact metal plate 6 is in a non-deformed state of the bimetal 8, and the movable contact 7 is brought into contact with the fixed contact 5 to set the circuit breaker to the on state, and the reverse bending state of the bimetal 8 Next, the elastic arm 6A pressed by the bimetal 8 is elastically deformed to separate the movable contact 7 from the fixed contact 5, thereby turning the circuit breaker off. The movable contact metal plate 6 is a phosphor bronze having a thickness of 100 μm. However, an elastic metal plate other than phosphorus removal bronze having a thickness of 200 μm or less can be used as the movable contact metal plate. However, if it is too thin, the current capacity becomes small, so a metal plate having a thickness of 50 μm or more is used. The resistance of the movable contact metal plate 6 and the fixed contact metal plate 4 is specified by material, thickness and width. These metal plates can reduce electrical resistance by reducing metal resistivity, thickening, and widening. The resistance is the amount of heat generated in a specific energized state. The thermal energy of Joule heat generated by the flow of current increases in proportion to the square of the current and the product of the resistance. The heat generated by the Joule heat heats the bimetal 8 to reverse it. When the bimetal 8 is reversed, the movable contact 7 is separated from the fixed contact 5 and switched to the off state. The circuit breaker 30 reverses the bimetal 8 by the heat generated by the resistance of the movable contact metal plate 6 and the fixed contact metal plate 4, so that if a current of a specific value or more flows, the ambient temperature does not rise. The current can still be cut off to the set temperature. The temperature at which the bimetal 8 is reversed is specified by the resistance of the movable contact metal plate 6 and the fixed contact metal plate 4 and the current flowing therein. The circuit breaker with the large resistance of the movable contact metal plate 6 and the fixed contact metal plate 4 is such that the bimetal 8 is reversed to cut off the current with a small current, and the circuit with a small resistance is larger. The energization current reverses the bimetal 8 to cut off the current. Therefore, the temperature at which the bimetal 8 is reversed is specified by current and resistance. Therefore, the current of the bimetal 8 can be reversed by the resistance of the specific movable contact metal plate 6 and the fixed contact metal plate 4. That is, the current of the circuit breaker cut-off current can be specified according to the resistance of the metal plate. Therefore, the resistance of the movable contact metal plate 6 and the fixed contact metal plate 4 is set to, for example, a resistance in which the set current for switching the contact to be off is 1A to 10A. In the on state, current flows in both the movable contact metal plate 6 and the fixed contact metal plate 4. Therefore, since the metal plates of both of them heat the bimetal 8 by Joule heat generation, the cutting current can be specifically determined according to the electric resistance of both the movable contact metal plate 6 and the fixed contact metal plate 4. However, if the resistance of the movable contact metal plate 6 is greater than the resistance of the fixed contact metal plate 4, the set current of the cut-off current is greater. Since the resistance of the movable contact metal plate 6 is larger than that of the fixed contact metal plate 4, and it is disposed adjacent to the bimetal 8, it is disposed at the opposite position. The reason why the resistance of the movable contact metal plate 6 is large is that phosphor bronze or the like is used because the elastic arm 6A is required to have elasticity. Further, since the bimetal 8 is disposed between the movable contact metal plate 6 and the PTC heater 9, the movable contact metal plate 6 is disposed at the opposite position of the bimetal 8, but the fixed contact metal plate 4 is The PTC heater 9 is placed and configured. Therefore, switching the contact to the off state and cutting off the set current of the current can be mainly adjusted by the resistance of the movable contact metal plate 6. Further, the movable contact metal plate 6 shown in FIGS. 3 to 6 is provided with a convex portion 6C on the side of the bimetal 8 . The movable contact metal plate 6 in the drawing is provided in contact with one of the pair of bimetals 8 so that the convex portion 6C protrudes toward the bimetal 8 side. As shown in FIG. 7, the pair of convex portions 6C are disposed on the center line m extending in the longitudinal direction of the movable contact metal plate 6 and spaced apart in the longitudinal direction of the movable contact metal plate 6. The movable contact metal plate 6 presses the outer peripheral edge portions of both ends of the bimetal 8 in contact with the pair of convex portions 6C. The convex portion 6C shown in the figure has an outer shape of an arc shape, and it is not necessary to slide the peripheral edge portion 8b of the bimetal 8 in the lateral direction, and can reliably contact each other and press each other. Although not shown, the movable contact metal plate may be provided with a plurality of convex portions on the lower surface opposite to both end portions of the bimetal. The circuit breaker 30 shown in Figs. 2 to 7 is formed of a cover case 3 having a body shell 2 made of plastic and a plastic body portion. The outer casing 1 of FIGS. 2 to 7 is formed by inserting and fixing the fixed contact metal plate 4 to the bottom portion 13 of the main body casing 2, and fixing the cover case 3 to the upper surface. The main body casing 2 is provided such that the first outer wall 11A and the second outer wall 11B protrude from both end portions, and a storage space 20 is provided between the first outer wall 11A and the second outer wall 11B. The storage space 20 closes the bottom surface with the fixed contact metal plate 4, and closes the upper surface with the cover case 3. Therefore, in the outer casing 1, the fixed contact metal plate 4 is exposed on the surface on the bottom surface side. The movable contact metal plate 6, the fixed contact metal plate 4, and the cover case 3 are fixed to the body case 2. The main body casing 2 is provided on both sides of the storage space 20 in which the bimetal 8 and the PTC heater 9 are housed, and is provided with a first outer wall 11A and a second outer wall 11B, and is further provided between the first outer wall 11A and the second outer wall 11B. The opposing wall 12 is composed of a pair of opposing walls 12 and a pair of outer walls 11 that surround the peripheral wall 10 around the accommodation space 20. Therefore, the accommodating space 20 is surrounded by the outer peripheral wall 10, and the bottom surface thereof is closed by the fixed contact metal plate 4, and the upper surface of the accommodating case is closed by the cover case 3, thereby becoming hollow inside. The main body casing 2 is formed by inserting the intermediate portion 4B of the fixed contact metal plate 4 into the first outer wall 11A in FIGS. 3 and 4, and fixing one of the fixed contact metal plates 4 to the first outer wall 11A. Therefore, the fixed contact metal plate 4 is fixed to the main body casing 2 in a state of penetrating the first outer wall 11A, and a portion exposed inside the storage space 20 serves as a fixed contact 5, and the protruding piece 4X taken out to the outside is used as a fixed side. The connection terminal 42. Further, the main body casing 2 is fixed to the fixing portion 6B of the movable contact metal plate 6 by the second outer wall 11B, and the elastic arm 6A of the movable contact metal plate 6 is disposed in the housing space 20. The circuit breaker 30 of FIGS. 3 and 4 is a fixed portion 6B to which the movable contact metal plate 6 is fixed to the upper end surface of the second outer wall 11B. As shown in FIG. 3, FIG. 4 and FIG. 7, the main body casing 2 is provided with a stepped recess 21 which is one step lower than the upper surface of the outer peripheral wall 10 on the upper end surface of the second outer wall 11B, so that the movable contact metal plate 6 is The fixing portion 6B is fitted to the stepped recess 21 and is disposed at a fixed position. The main body casing 2 in the figure is provided with a coupling convex portion 15 that protrudes from the central portion of the fitting recessed portion 21 and penetrates the fixing portion 6B of the movable contact metal plate 6. A through hole 6F through which the connection convex portion 15 penetrates is provided in the fixing portion 6B of the movable contact metal plate 6. The connecting convex portion 15 shown in FIG. 7 has an elliptical horizontal cross-sectional shape so that the fixed portion 6B of the movable contact metal plate 6 can be placed in the stepped recess portion 21 in a correct posture. Further, the stepped recessed portion 21 shown in FIG. 7 is formed by positioning ribs 22 on both side portions of the movable contact metal plate 6 at the upper end portion of the second outer wall 11B. The second outer wall 11B shown in Fig. 7 is formed with a stepped shape rib 22 by providing a recessed portion 21 so that the portion other than the positioning rib 22 is lower than the upper surface of the outer peripheral wall 10. The movable contact metal plate 6 is provided with positioning recesses 6G for guiding the positioning ribs 22 on both sides of the fixed portion 6B. The movable contact metal plate 6 is inserted into the through hole 6F of the opening of the fixing portion 6B, and is guided by the positioning rib 22 to the positioning concave portion 6G provided on both sides of the fixing portion 6B, and is disposed on the second outer wall 11B. The fixed position of the stepped recess 21 is. The fixed portion 6B is fixed to the second outer wall 11B via the movable contact metal plate 6 disposed in the stepped recess 21, or is sandwiched and fixed to the cover case 3 of the main body case 2, that is, the stepped recess portion of the second outer wall 11B. The bottom surface of the cover 21 and the opposite side of the cover case 3 are clamped from the upper and lower sides and fixed to the fixed position of the outer casing 1. As shown in FIG. 2 to FIG. 7 , the cover case 3 is provided with a laminated metal plate 25 which is attached to the opening side of the upper end of the main body case 2, laminated on the outer side of the movable contact metal plate 6 , and a plastic material 26 connected thereto. The laminated metal plate 25 is fixed. The cover case 3 exposes the laminated metal plate 25 toward the inner surface side, that is, the side of the main body case 2, and is placed on the opening side of the main body case 2 so as to cover the upper side of the movable contact metal plate 6 by the laminated metal plate 25. The case cover 3 shown in FIGS. 2 to 7 is insulated on the upper surface side by the substantially entire surface of the laminated metal plate 25 to which the plastic material 26 is bonded. The laminated metal plate 25 is insert-molded and fixed to the joined plastic material 26. The insert-formed laminated metal plate 25 is temporarily fixed to a molding chamber of a metal mold for molding the plastic material 26, and is fixed to the joint plastic material 26 by molding the molding chamber into a molten state. The cover case 3 is fixed to the outer surface of the outer peripheral wall 10 of the main body casing 2 by the outer peripheral portion of the joint plastic material 26, and is fixed to the main body casing 2. As shown in FIG. 6, the connecting plastic material 26 of the cover case 3 has a peripheral wall 27 projecting toward the main body casing 2 on the outer peripheral edge portion opposite to the outer peripheral wall 10 of the main body casing 2, and the laminated metal plate 25 is placed thereon. The inner side of the outer peripheral wall 27 is exposed. The outer peripheral wall 27 of the connected plastic material 26 is fixed to the first outer wall 11A and the second outer wall 11B provided at both end portions of the main body casing 2, and is further fixed to the opposite wall 12. The outer casing 1 shown in Fig. 6 is provided with coupling projections 15, 17 and coupling recesses 16, 18 which are fitted to each other for the purpose of properly positioning one side of the cover case 3 and the main body case 2. As described above, the main body casing 2 protrudes from the upper surface of the second outer wall 11B, and is provided with a coupling convex portion 15 that passes through the fixing portion 6B of the movable contact metal plate 6 and is positioned. The cover case 3 is attached to an end portion of the main body case 2 on the second outer wall 11B side, and a connection recess portion 16 for guiding the connection convex portion 15 is provided at a position opposed to the connection convex portion 15. Further, the cover case 3 shown in FIG. 6 is provided on both sides of the end portion on the first outer wall 11A side of the main body case 2, and is provided with a coupling convex portion 17 projecting from the lower surface of the outer peripheral wall 27 toward the main body case 2. As shown in FIG. 7, the main body casing 2 is provided with a coupling recess 18 for guiding the connection convex portion 17 on the upper surface of the opposing wall 12 opposed to the coupling convex portion 17. The outer casing 1 is attached to the end portion of the main casing 2 on the first outer wall 11A side, and the coupling convex portion 17 on both sides of the cover shell 3 is guided by the coupling recess 18 of the main body casing 2, and the outer wall of the casing 2 is provided on the outer wall of the casing 2 The end portion of the 11B side is guided by the connecting concave portion 16 of the cover case 3 so as to pass through the connecting convex portion 15 of the fixed portion 6B of the movable contact metal plate 6, and the cover case 3 is coupled to the correct position of the body case 2. The cover case 3 and the main body case 2, which are connected to the fixed position via the connection convex portions 15 and 17 and the connection concave portions 16 and 18, are ultrasonically welded to fix the connection plastic material 26 to the main body case 2. The cover case 3 shown in FIG. 6 is provided with a molten ridge 19 which is melted by ultrasonic vibration, and the molten ridge 19 is located on the upper surface of the peripheral wall 27 of the joint plastic material 26 and is adjacent to the outer wall of the body case 2. 10 opposite directions. The cover case 3 in the figure is along the lower surface of the outer peripheral wall 27, and a molten ridge 19 is protruded. The cover case 3 is provided on a peripheral portion other than a portion opposed to the fixed portion 6B of the movable contact metal plate 6, and a fusion ridge 19 having a substantially U-shaped shape in plan view is provided. The cover case 3 is ultrasonically vibrated by the outer peripheral portion in a state where the cover case 3 is coupled to the fixed position of the main body case 2 via the connection convex portions 15 and 17 and the connection concave portions 16 and 18, and the molten ridge 19 is melted and welded by friction heat. The peripheral wall 10 is outside the body casing 2. Further, the cover case 3 and the main body case 3 which are ultrasonically vibrated are also welded to each other by frictional fusion of the contact portions of the connection convex portions 15, 17 which are connected to each other by frictional fusion. However, the outer casing may be attached to the body plastic of the cover case and connected to the body case by an embedded structure or an engaging structure. The circuit breaker 30 shown in FIG. 2 and FIG. 3 is a self-laminated metal plate 25 in such a manner that the movable contact 7 can be surely contacted with the fixed contact 5 in a state where the bimetal 8 is not thermally deformed. A pressing convex portion 25A that presses the rear end portion of the elastic arm 6A downward is provided on the inner surface. The movable contact metal plate 6 is pressed against the rear end portion of the elastic arm 6A by the pressing convex portion 25A, and the front end portion of the elastic arm 6A is energized downward, and the movable contact 7 at the front end is surely brought into contact with the fixed joint. Point 5. Further, the outer casing 1 shown in FIGS. 3 to 6 is attached to the bottom of the housing space 20 of the main body casing 2, and a heater housing portion 29 in which the PTC heater 9 is disposed is provided. The heater housing portion 29 is provided inside the bimetal receiving portion 28 and at the bottom thereof. The heater housing portion 29 is a recess that prevents the PTC heater 9 from being detached from the fixed position. The PTC heater 9 is then fixed to the heater housing portion 29 or is fixed to the heater housing portion 29 in order to prevent detachment. The heater accommodating portion 29 is located at the central portion of the accommodating space 20, and the bottom surface of the fixed contact metal plate 4 is closed by the exposed plate portion 4A. The heater housing portion 29 has a shape in which the PTC heater 9 can be inserted therein, and its inner shape is slightly larger than that of the PTC heater 9. Further, the heater housing portion 29 is provided with a convex portion 14 along the outer peripheral edge. The PTC heater 9 inserted into the heater accommodating portion 29 slightly protrudes from the upper surface of the convex portion 14, and the bimetal 8 bent toward the upper surface is placed. In the storage space 20, the bottom surface of the heater accommodating portion 29 is closed by the fixed contact metal plate 4, and the outer surface of the heater accommodating portion 29 is closed by the plastic material of the main body casing 2. The main body casing 2 is a plastic bottom portion 13 that closes the bottom of the storage space 20 from the outside of the heater housing portion 29, and the fixed contact metal plate 4 is insert-molded and fixed to the main body casing 2. The circuit breaker 30 shown in FIG. 2 to FIG. 7 is attached to the storage space 20 of the main body casing 2, and the PTC heater 9, the bimetal 8 and the elastic arm 6A of the movable contact metal plate 6 are sequentially stored from the bottom, and are fixedly connected. The intermediate portion 4B of the point metal plate 4 is fixed to the first outer wall 11A of the main body casing 2, and the fixed portion 6B of the movable contact metal plate 6 is fixed to the second outer wall 11B. The fixed contact metal plate 4 is insert-molded and fixed to the body casing 2. The fixed contact metal plate 4 closes the opening portion of the bottom portion 13 of the storage space 20 with the exposed plate portion 4A, and the intermediate portion 4B and the front end of the exposed plate portion 4A are embedded in the body case 2 from the bottom portion 13 of the storage space 20. The first outer wall 11A is insert-molded and fixed to the main body casing 2. In the fixed contact metal plate 4 of FIG. 3 and FIG. 4, the step portion 4D is provided so that the portion buried in the first outer wall 11A is closer to the bottom portion of the heater accommodating portion 29, and the step portion 4D is buried in the body. The bottom portion 13 of the case 2 exposes the end portion of the step portion 4D to the upper surface of the bottom portion 13, and the exposed portion serves as the fixed contact 5. As shown in FIGS. 8 and 9, the fixed contact metal plate 4 is pressed into the silver plate 35 as a fixed contact 5 to the metal plate. The metal plate of the fixed joint 5 is copper or copper alloy, or nickel or nickel alloy. The thicker silver panel 35 can increase the contact life, so the thickness is set to 200 μm. However, as shown in FIGS. 10 and 11, the fixed contact metal plate 4 may be silver plated on the surface to form the silver plating layer 36 as the fixed contact 5. The silver plating layer 36 of the fixed contact 5 is thicker than the silver plating layer 37 of the movable contact 7, for example, 6 μm. However, the film thickness of the silver plating layer of the fixed contact can be set to 5 to 100 μm, preferably 3 to 50 μm, and can be made thicker than the movable contact. By making the silver-plated layer of the fixed contact thicker, the fixed contact can be connected to the polarity that is easily damaged to increase the connection life. The PTC heater 9 heats the bimetal 8 by energization. The PTC heater 9 is a PTC heater having a certain thickness in a circular or elliptical opposite surface, and electrodes are provided on the upper surface and the lower surface. The PTC heater 9 provided with electrodes on the upper and lower surfaces is such that the lower surface is in contact with the fixed contact metal plate 4 so that the upper surface can contact the movable contact metal plate 6 via the bimetal 8. The PTC heater 9 is in a state in which the movable contact 7 of the movable contact metal plate 6 is in contact with the fixed contact 5, and the movable contact metal plate 6 and the bimetal 8 are in a non-contact state and are not energized; When the movable contact 7 of the movable contact metal plate 6 is separated from the fixed contact 5 and is in the off state, the bimetal 8 and the fixed contact metal plate 4 that are in contact with the movable contact metal plate 6 are energized to generate heat. While heating the bimetal 8. The heated bimetal 8 is shown in Fig. 4, and the movable contact 7 is held in a disconnected state from the fixed contact 5. Since the circuit breaker 30 can be kept in the off state while being switched to the off state, the movable contact 7 can be kept in the off state, so that it can be used for the battery pack, and safety can be improved. This is because after the battery composition is abnormal temperature and the circuit breaker 30 is switched off, the battery of the battery pack is continuously energized to the PTC heater 9 to heat the bimetal 8, so that the circuit breaker 30 does not return to the ON state. It can be kept in the state of cutting off the current until the battery is discharged. If the battery is completely discharged, the PTC heater can no longer be energized. Therefore, the PTC heater cannot heat the bimetal. Although the circuit breaker returns to the ON state, the battery cannot be discharged in this state, so safety can be ensured. Furthermore, even in the case where the battery pack is set to an abnormal temperature in a state in which the battery pack is connected to the charger and the circuit breaker is turned off, the current can be maintained by energizing the PTC heater by the power supplied from the charger. In the off state, the circuit breaker does not return to the on state, and can be kept in a state of being cut off from the period during which power is supplied from the charger. Therefore, since the battery pack is switched off after the circuit breaker is turned off, the PTC heater is energized to maintain the circuit breaker in the off state until the energization state is released, so that the safety can be further improved. The above-mentioned circuit breaker 30 is activated after the assembly is energized in a state in which the contact point is energized to cause the contact ultrasonic wave to vibrate. The circuit breaker causes the movable contact 7 and the fixed contact 5 to collide with each other to perform ultrasonic vibration in the direction away from the direction. That is, the circuit breaker vibrates the contact ultrasonic wave so that the fixed contact and the movable contact approach each other to collide or move in a direction away from each other. In the state of ultrasonic vibration, the contact current is in a resistive load state, and is preferably set to 0.1 A to 100 A. The contact current at the time of ultrasonic vibration is increased to activate the contact more efficiently. When a certain load of the impedance of the coil is connected in series with the resistor, the current accumulated in the coil is increased when the current is cut off, so that the contact current can be weakened and the contact can be activated. Since the current stored in the coil is consumed, the discharge current at the contact becomes large. Therefore, the contact current is set to an optimum value in consideration of the resistive load and the impedance load. Further, the circuit breaker has a characteristic that when the current of the contact is increased, the Joule heat is generated and the self is switched to the off state. In order to activate the contact by ultrasonic vibration, it is necessary to maintain the contact state of the movable contact 7 in contact with the fixed contact 5. Therefore, the method of causing a large current to flow at the contact to vibrate the ultrasonic wave shortens the time of the ultrasonic vibration, and the ultrasonic wave is vibrated while the contact is in the ON state. Therefore, the method of causing a supersonic wave to flow a large current at a contact shortens the time during which the ultrasonic vibration is caused. The time during which the contact ultrasonic vibration is applied in the energized state is set to 0.1 millisecond to 1 millisecond. Although the contact ultrasonic vibration is activated for a longer period of time, the contact can be activated more effectively. However, if the contact is damaged if it is too long, it is set to a time when the contact can be activated without damaging the contact. Moreover, the contact activation by ultrasonic vibration is also affected by the contact current, the type of load, and the amplitude of the ultrasonic vibration. Therefore, if the contact current and amplitude are large, the contact can be made in a short time. Start up effectively. Therefore, the time of the ultrasonic vibration is considered to be an optimum value within the above range in consideration of the amplitudes of the contact current and the ultrasonic vibration. Further, the frequency of the contact ultrasonic vibration is set to 20 KHz to 6 GHz, preferably 20 KHz to 1 GHz. The frequency of the ultrasonic vibration can be increased to increase the number of collisions and the number of deviations between the movable contact 7 and the fixed contact 5 per unit time. However, if the frequency of the ultrasonic vibration is too high, the interval between the movable contact 7 and the fixed contact 5 becomes shorter, and the start of the discharge is reduced. Conversely, if the frequency is too low, the number of collisions is reduced and the startup is reduced. The frequency of the ultrasonic vibration is set to an optimum value in consideration of the thickness and length of the elastic arm 6A, and further considering the resonance frequency of the elastic arm 6A. Further, the amplitude of the ultrasonic vibration of the circuit breaker is set to 0.01 μm to 1000 μm. The amplitude of the ultrasonic vibration can be increased to increase the kinetic energy of the movable contact 7 colliding with the fixed contact 5, or the interval between the movable contact 7 and the fixed contact 5 can be increased. The amplitude of the ultrasonic vibration of the circuit breaker affects the interval separating the movable contact 7 from the fixed contact 5. However, the distance between the movable contact 7 and the fixed contact 5 can be made larger than the amplitude of the ultrasonic vibration of the circuit breaker by causing the elastic arm 6A to resonate. Therefore, the movable contact 7 can be made by setting the frequency of the ultrasonic vibration of the circuit breaker to the resonance frequency of the elastic arm 6A, or the frequency in the vicinity thereof, or an integer multiple of the resonance frequency, and an integral number of the resonance frequency. Separate enough distance from the fixed contact 5 to enable efficient starting. In order to increase the amplitude of the ultrasonic vibration of the circuit breaker, it is necessary to increase the output of the ultrasonic vibrator or ultrasonic horn that contacts the circuit breaker and vibrates it. When a large-output ultrasonic vibrator or a supersonic welding head is pressed to the outer casing 1 of the circuit breaker to cause ultrasonic vibration, there is a disadvantage that the contact portion with the ultrasonic vibrator is deformed by the heat generated by the ultrasonic vibration. Therefore, the amplitude of the ultrasonic vibration of the circuit breaker is set to be small within the range in which the contact is activated. Then, the USB plug can also be configured as shown in FIG. The USB plug shown in the figure is arranged in a posture in which the circuit breaker 30 of the USB plug shown in Fig. 1 is turned upside down. In other words, the circuit breaker 30 incorporated in the USB plug shown in FIG. 12 is attached to the circuit board 55 in such a manner that the exposed portion 4A made of metal exposed from the outer casing 1 is exposed on the front side of the outer casing 1. The USB plug embeds the exposed plate portion 4A in the inner plastic body 51A in a sealed state. Thereby, the exposed plate portion 4A exposed on the surface of the circuit breaker 30 is adhered to the inner plastic material 51A in a thermally coupled state, and heat energy is efficiently conducted to the circuit breaker 30 via the inner plastic material 51A. Further, in the USB connector shown in FIG. 12, the heat transfer plate 58 connected to the metal can 56 in a thermally coupled state is embedded in the lid portion 51, and the heat transfer plate 58 is placed in the outer casing 1 of the circuit breaker 30 in a thermally coupled state. Since the USB plug thermally couples the metal can 56 of the plug portion 52 to the circuit breaker 30 via the heat conducting plate 58, the thermal energy of the metal can 56 can be efficiently conducted to the circuit breaker 30. In particular, the USB plug shown in FIG. 12 is provided with a metal exposed plate portion 4A exposed on the surface of the circuit breaker 30, and is disposed in a state in which the heat conducting plate 58 is thermally coupled to the exposed plate portion 4A. Therefore, it is possible to detect the temperature rise of the plug portion 52 more sensitively and cut off the circuit. [Industrial Applicability] The USB plug of the present invention can prevent excellent failure due to malfunction due to static electricity or the like, and can prevent the contact from being overcurrent, so that it can be plugged and connected to an electron such as a flat plate. The USB plug of the USB connector of the machine is especially preferred as the best USB plug for supplying power to an electronic device.

1‧‧‧Shell
1T‧‧‧Bottom of the casing
2‧‧‧ body shell
3‧‧‧ Cover
4‧‧‧Fixed joint metal plate
4A‧‧‧ exposed board
4B‧‧‧Intermediate
4D‧‧‧ step department
4X‧‧‧ highlights
5‧‧‧Fixed joints
6‧‧‧ movable contact metal plate
6A‧‧‧Flexible arm
6B‧‧‧Fixed Department
6C‧‧‧ convex
6D‧‧‧Protruding
6E‧‧‧Returned tablets
6F‧‧‧through hole
6G‧‧‧ positioning recess
6X‧‧‧ highlights
7‧‧‧ movable contact
8‧‧‧ bimetal
9‧‧‧PTC heater
10‧‧‧ peripheral wall
11‧‧‧ outer wall
11A‧‧‧1st outer wall
11B‧‧‧2nd outer wall
12‧‧‧ opposite wall
13‧‧‧ bottom
14‧‧‧ convex
15‧‧‧Connecting convex
16‧‧‧Connecting recess
17‧‧‧Connecting convex
18‧‧‧Connecting recess
19‧‧‧Fused ribs
20‧‧‧Storage space
21‧‧ ‧ step recess
22‧‧‧ positioning ribs
25‧‧‧Laminated metal sheets
25A‧‧‧ Pressing the convex part
26‧‧‧Link plastic
27‧‧‧ peripheral wall
28‧‧‧Bimetal storage unit
29‧‧‧Heater storage unit
30‧‧‧Circuit breaker
35‧‧‧ Silver material
36‧‧‧Silver plating
37‧‧‧Silver plating
41‧‧‧Connecting terminal
42‧‧‧Fixed side connection terminals
51‧‧‧ 盖部
51A‧‧‧ inside plastic
51B‧‧‧Outside plastic
52‧‧‧ plug part
53‧‧‧External connection contacts
54‧‧‧temperature switch
55‧‧‧ circuit board
56‧‧‧Metal tube
57‧‧‧Insert substrate
58‧‧‧heat conducting plate
60‧‧‧ lead
90‧‧‧ cable
91‧‧‧ 盖部
92‧‧‧ plug part
93‧‧‧Current cut-off IC
94‧‧‧ Thermal protection circuit temperature switch IC
95‧‧‧ circuit board
96‧‧‧Metal shell
97‧‧‧Metal connecting members
M‧‧‧ center line

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing a USB connector according to an embodiment of the present invention. Fig. 2 is a perspective view showing an example of a circuit breaker. Fig. 3 is a vertical longitudinal sectional view showing the ON state of the circuit breaker shown in Fig. 2. Fig. 4 is a vertical longitudinal sectional view showing the disconnected state of the circuit breaker shown in Fig. 3. Figure 5 is a cross-sectional view taken along line IV-IV of the circuit breaker shown in Figure 3. Figure 6 is an exploded cross-sectional view showing the circuit breaker shown in Figure 3. Fig. 7 is a plan view showing the body casing of the circuit breaker shown in Fig. 6. Fig. 8 is an enlarged cross-sectional view showing the joint structure of the circuit breaker shown in Fig. 4. Fig. 9 is an enlarged cross-sectional view showing another example of the contact structure. Fig. 10 is an enlarged cross-sectional view showing another example of the contact structure. Fig. 11 is an enlarged cross-sectional view showing another example of the contact structure. Figure 12 is a schematic cross-sectional view showing a USB connector according to an embodiment of the present invention. Figure 13 is a schematic cross-sectional view of a prior USB connector.

30‧‧‧Circuit breaker

51‧‧‧ 盖部

51A‧‧‧ inside plastic

51B‧‧‧Outside plastic

52‧‧‧ plug part

53‧‧‧External connection contacts

54‧‧‧temperature switch

55‧‧‧ circuit board

56‧‧‧Metal tube

57‧‧‧Insert substrate

60‧‧‧ lead

Claims (9)

A USB plug comprising: a plastic cover portion that connects one end of a lead wire; and a plug portion that is fixed to the cover portion and that is detachably connected to an external connection device, that is, a USB connector of an electronic device; a connection contact, which is disposed on the plug portion; and a temperature switch connected between the external connection contact and the lead; wherein the temperature open relationship detects a circuit breaker that is switched to an off temperature when the temperature is higher than a set temperature; The circuit breaker includes: a casing; a fixed contact metal plate including a fixed contact fixed to the outer casing; and a movable contact metal plate disposed at a position opposite to a fixed contact of the fixed contact metal plate a resilient arm of the contact, and fixing the fixing portion of one end of the elastic arm to the outer casing in such a manner that the elastic arm is movable; and a bimetal pressing the elastic arm of the movable contact metal plate The movable contact is separated from the fixed contact; the PTC heater is located at a position for heating the bimetal and is connected to the movable contact metal plate and the upper The fixed contact metal plate; the elastic arm of the movable contact metal plate has the elasticity of the movable contact contacting the fixed contact by the elasticity thereof without being pressed by the bimetal; a bimetal is disposed between the elastic arm and the PTC heater; and in the non-deformed state in which the bimetal is not thermally deformed, the movable contact is elastically contacted with the fixed contact by the elastic arm In an inverted state in which the bimetal is thermally deformed, the bimetal presses the elastic arm to separate the movable contact from the fixed contact into an open state; and in an open state Next, the PTC heater heats the bimetal and is kept in an off state. The USB plug of claim 1, comprising: a circuit board disposed on the cover portion; and the circuit breaker being fixed to the circuit board. The USB plug of claim 2, wherein the plastic cover portion comprises: an inner plastic material, a portion of the plug portion, the circuit substrate, the circuit breaker, and one of the lead wires; and an outer plastic material embedded therein The inner plastic material mentioned above. The USB plug of claim 3, wherein the inner plastic material of the USB plug is a hot-melt plastic material; and the inner plastic material is insert-molded and fixed to the outer plastic material. The USB plug of claim 3, wherein the circuit breaker of the USB plug includes an exposed metal portion exposed to a surface, and the exposed plate portion is embedded in the inner plastic body in a sealed state. The USB plug of claim 1, wherein the plug portion of the USB plug includes a metal can inserted into an electronic device, and a heat conducting plate coupled to the metal can is thermally coupled to the cover portion, wherein the heat conducting plate is thermally coupled The state is disposed on the outer casing of the circuit breaker, and the circuit breaker is thermally coupled to the metal cylinder interposed between the heat conducting plates. The USB plug according to claim 6, wherein the circuit breaker includes an exposed metal portion exposed to a surface, and the heat transfer plate is disposed in the exposed plate portion of the circuit breaker in a thermally coupled state. The USB plug of claim 1, wherein the circuit breaker has a resistance of one or both of the movable contact metal plate and the fixed contact metal plate, and is set to a Joule heat of an overcurrent greater than a set current. The above bimetal is heated and switched to the resistance value of the off state. The USB plug of claim 1, wherein the USB plug is a micro USB connector.