JP2013258797A - Safety device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety device requiring no control device and thereby achieving simplification and inexpensiveness.SOLUTION: A safety device 1 is connected between a DC power source 2 and a heater 3 and includes a normal line 5 connected to the DC power source 2, a commutation line 8 connected in parallel to the normal line 5, a resistance 7 provided on the commutation line 8, a commutation device 6 interrupts the normal line 5 to commutate an electric current flowing through the normal line 5 into the commutation line 8, and a circuit breaker 10 connected in series to the normal line 5 and the commutation line 8 or to the commutation line 8. The circuit breaker 10 includes a bimetal which directly or indirectly receives heat from the resistance 7 and deforms when reaching to a critical temperature. The circuit breaker 10 opens by the deformation of the bimetal.

Description

  The present invention relates to a safety device that interrupts a direct current when an abnormality occurs.

  Patent document 1 is disclosing the safety device which connected the commutation circuit breaker and the resistance and circuit breaker for large current interruption in parallel.

  This safety device is connected between the power source (generator) and the load (main transformer). In the event of an abnormality, the commutation breaker is opened and the current is commutated to the resistor to attenuate the current. By opening the large current breaker in the state, arc discharge is suppressed and the direct current is safely interrupted.

JP-A-7-161264

  However, the configuration of the above prior art requires a control device for operating the commutation breaker and the large current breaker with a time difference, which has been a factor in increasing the cost of the safety device.

  The present invention has been made in view of such technical problems, and it is an object of the present invention to simplify a safety device without using a control device and to reduce the cost of the safety device.

  According to an aspect of the present invention, a safety device connected between a DC power supply and a load, the normal time line connected to the DC power supply, and a commutation line connected in parallel to the normal time line; A resistance provided in the commutation line; a commutator that cuts off the normal line; and commutates the current flowing in the normal line to the commutation line; and the normal line and the commutation. A heat-controlling member that is connected in series to the line, or connected in series to the commutation line, and directly or indirectly receives heat from the resistor and deforms when reaching a critical temperature; There is provided a safety device comprising a circuit breaker that opens upon receiving deformation of a deformable member.

  According to the said aspect, the control apparatus for operating a commutator and a circuit breaker with a time lag is unnecessary, and can reduce the cost of an apparatus.

It is an electric circuit diagram of the safety device concerning a 1st embodiment. It is a perspective view which shows the specific structure of the safety device which concerns on 1st Embodiment. It is a figure for demonstrating the structure and operation | movement of a commutator. It is a figure for demonstrating the structure and operation | movement of a commutator. It is a figure for demonstrating the structure and operation | movement of a circuit breaker. It is a figure for demonstrating the structure and operation | movement of a circuit breaker. It is a figure for demonstrating operation | movement of a safety device. It is a figure for demonstrating operation | movement of a safety device. It is a figure for demonstrating operation | movement of a safety device. It is an electric circuit diagram of the safety device concerning a 2nd embodiment. It is a perspective view which shows the specific structure of the safety device which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is an electric circuit diagram of the safety device 1 according to the first embodiment.

  In the figure, the DC power source 2 is a high-power battery having an output voltage of 350 V mounted on a hybrid vehicle. The heater 3 is a sheathed heater or a PTC heater that generates heat when energized. In terms of cost, a sheathed heater is preferable. The heater 3 is disposed in the hot water tank 4 and heats the refrigerant flowing in the hot water tank 4.

  The safety device 1 is connected between the DC power source 2 and the heater 3. The safety device 1 interrupts the current flowing from the DC power supply 2 to the heater 3 when the temperature of the hot water tank 4 rises beyond the allowable temperature range.

  The safety device 1 is connected to the positive electrode side of the heater 3 in the direction of electricity flow, even if the components of the safety device 1 are short-circuited to an external electric circuit at the time of current interruption. This is to prevent current from flowing from 2 to the heater 3.

  The configuration of the safety device 1 will be described. The safety device 1 includes a normal line 5 connected to a DC power supply 2, a commutator 6 provided in the normal line 5, and a commutation line connected in parallel to the normal line 5 and provided with a resistor 7. 8 and a circuit breaker 10 connected in series to the normal line 5 and the commutation line 8 via the merge line 9.

  The commutator 6 is a bimetal switch including a bimetal as an actuator that drives a movable contact. The commutator 6 is installed on the upper surface of the hot water tank 4. The commutator 6 is closed if the bimetal is lower than the critical temperature, but opens when the temperature of the bimetal reaches the critical temperature by heat received from the hot water tank 4. At this time, the spring-biased insulator 66 is inserted between the opened contacts, and the commutator 6 is reliably opened.

  As with the commutator 6, the circuit breaker 10 is a bimetal switch including a bimetal as an actuator that drives a movable contact. The circuit breaker 10 is installed on the upper surface of the resistor 7. The circuit breaker 10 is closed if the bimetal is lower than the critical temperature, but opens when the temperature of the bimetal reaches the critical temperature by the heat received from the resistor 7.

  FIG. 2 is a perspective view showing a specific configuration of the safety device 1.

  The commutator 6 includes a fixed contact 61, a movable contact 62 disposed opposite to the fixed contact 61, a bimetal 63 disposed below the movable contact 62, and an operation extending from the bimetal 63 toward the movable contact 62. A rod 64 and an insulator 66 urged toward the movable contact 62 by a torsion spring 65 are provided.

  The bimetal 63 has a convex ridge shape below the critical temperature, but when it reaches the critical temperature, it deforms into a convex ridge shape on the upper side. As a result, the distal end of the operating rod 64 is pressed against the movable contact 62, the movable contact 62 is pushed up, and the movable contact 62 is separated from the fixed contact 61.

  The circuit breaker 10 includes a fixed contact 101, a movable contact 102 disposed opposite to the fixed contact 101, a bimetal 103 disposed below the movable contact 102, and an operating rod extending from the bimetal 103 toward the movable contact 102. 104. The configuration and operation mode of the bimetal 103 are the same as those of the bimetal 63.

  FIG. 3A shows the commutator 6 when the bimetal 63 is below the critical temperature. In this state, the movable contact 62 and the fixed contact 61 are in contact with each other, and the commutator 6 is closed.

  The insulator 66 has a fan-shaped blade portion 66b that becomes thinner as it is closer to the movable contact 62. A protrusion 67 extending in the displacement direction of the movable contact 62 is formed on the upper surface of the blade portion 66b on the movable contact 62 side. Is provided. The insulator 66 is pivotally supported by the shaft portion 66s and is urged clockwise by a torsion spring 65 provided on the shaft portion 66s. The insulator 66 maintains the state shown in the figure when the protrusion 67 of the blade portion 66 b contacts the side surface of the movable contact 62. This prevents the commutator 6 from being accidentally opened.

  When the temperature of the bimetal 63 reaches a critical temperature from this state, the tip of the operating rod 64 is pressed against the movable contact 62, the movable contact 62 is pushed up, the movable contact 62 is separated from the fixed contact 61, and the commutator 6 is Open the pole.

  When the distance of the movable contact 62 from the fixed contact 61 becomes larger than the height of the protrusion 67 of the blade portion 66b, the biasing force of the torsion spring 65 causes the movable contact 62 to move between the movable contact 62 and the fixed contact 61 as shown in FIG. The blade portion 66b is inserted, and the distance between the movable contact 62 and the fixed contact 61 is further increased. Thereby, the commutator 6 is reliably opened. A stopper pin 68 is provided on the upper surface of the fixed contact 61 so as to restrict the amount of rotation of the insulator 66 by contacting the blade portion 66b.

  After the blade portion 66b is inserted between the movable contact 62 and the fixed contact 61, even if the temperature of the bimetal 63 is lowered to the self-recovery temperature (<critical temperature), the protrusion 67 of the blade portion 66b is moved to the movable contact 62. The blade portion 66b is not pulled out between the movable contact 62 and the fixed contact 61. That is, once the commutator 6 is opened, it is not closed again.

  The protrusion 67 may be provided on the lower surface of the movable contact 62 instead of the blade portion 66b.

  FIG. 4A shows the circuit breaker 10 when the bimetal 103 is below the critical temperature. In this state, the movable contact 102 and the fixed contact 101 are in contact with each other, and the circuit breaker 10 is closed.

  When the temperature of the bimetal 103 reaches a critical temperature from this state, the tip of the operating rod 104 is pressed against the movable contact 102 and the movable contact 102 is pushed up, and the movable contact 102 is separated from the fixed contact 101 as shown in FIG. 4B. Then, the circuit breaker 10 is opened.

  In the first embodiment, only the commutator 6 adopts a configuration in which the insulator 66 is inserted between the movable contact 62 and the fixed contact 61 when the pole is opened. A configuration may be adopted.

  Next, the operation of the safety device 1 according to the first embodiment will be described with reference to FIGS. 5A to 5C.

  When the temperature of the hot water tank 4 is normal within the allowable temperature range, both the commutator 6 and the circuit breaker 10 are closed. In this state, since the resistance value of the commutator 6 is smaller than the resistance value of the resistor 7, most of the current flows to the commutator 6 as shown in FIG. 5A.

  From this state, when the temperature of the hot water tank 4 rises beyond the allowable temperature range, the bimetal temperature of the commutator 6 reaches a critical temperature, and the commutator 6 opens as shown in FIG. 5B. As a result, the normal line 5 is cut off, and the current flowing in the normal line 5 is commutated to the commutation line 8.

  At this time, the resistance value of the commutator 6 becomes infinite, and current flows to the resistor 7 side as shown in FIG. 5B, so that arc discharge in the commutator 6 is suppressed. Furthermore, since the insulator 66 is inserted between the opened contacts of the commutator 6, the commutator 6 is reliably opened.

  When the current flowing through the resistor 7 increases, the temperature of the resistor 7 rises, and accordingly, the temperature of the bimetal of the circuit breaker 10 rises. When the temperature of the bimetal of the circuit breaker 10 reaches a critical temperature, the circuit breaker 10 is opened, but since the current flowing through the circuit breaker 10 is attenuated by the resistor 7, the arc discharge in the circuit breaker 10 is suppressed, The circuit breaker 10 can be safely opened.

  Thus, according to the first embodiment, the direct current can be safely interrupted. A control device for operating the commutator 6 and the circuit breaker 10 with a time difference is unnecessary, and the cost of the device can be reduced.

Second Embodiment
FIG. 6 is an electric circuit diagram of the safety device according to the second embodiment. FIG. 7 shows a specific configuration thereof.

  The second embodiment is different from the first embodiment in the connection position of the commutator 6. That is, in the second embodiment, the commutator 6 is provided at a node between the normal line 5 and the commutation line 8, and a current flows only in the normal line 5 in the closed state, and in the open state. A current is configured to flow only through the commutation line 8. That is, the state where the DC power source 2 and the normal line 5 are connected and the state where the DC power source 2 and the commutation line 8 are connected are realized exclusively.

  If the commutator 6 is provided at such a position, since the current does not flow through the resistor 7 when the temperature of the hot water tank 4 is within the allowable temperature range, the loss in the resistor 7 can be reduced.

  Since other functions and effects are the same as those of the first embodiment, description thereof is omitted.

  As mentioned above, although embodiment of this invention was described, the said embodiment showed only a part of application example of this invention, and is not the meaning which limits the technical scope of this invention concretely of the said embodiment. .

  For example, in the above embodiment, the commutator 6 is installed on the upper surface of the hot water tank 4 and the commutator 6 opens when the temperature of the hot water tank 4 exceeds the allowable temperature range. The commutator 6 may be installed in the vicinity of the heater 3 with the upper surface of 4 being recessed, and the commutator 6 may be opened when the temperature of the heater 3 exceeds the allowable temperature range.

  Further, the commutator 6 is constituted by a float switch and an inclination switch, and the commutator 6 is opened when the water level of the hot water tank 4 reaches the lower limit water level or when the inclination of the hot water tank 4 reaches the upper limit angle. You may make it do.

  Moreover, you may comprise the commutator 6 with a temperature fuse instead of a bimetal switch.

  In the case of a thermal fuse, even if the temperature of the hot water tank 4 exceeds the allowable temperature range and melts, a slight current may flow through the line 5 during normal operation. Even so, since the resistance value of the commutator 6 is larger than the resistance value of the resistor 7, the same effect as the above embodiment can be obtained.

  Further, instead of the resistor 7, a PTC thermistor or a capacitor whose resistance value changes according to the temperature may be used.

  Moreover, in the said embodiment, although the circuit breaker 10 is connected in series to the normal time line 5 and the commutation line 8, the circuit breaker 10 should just be connected in series to the commutation line 8, for example, the merge line 9 and A circuit breaker 10 may be provided between the node with the commutation line 8 and the resistor 7.

  Although not particularly shown, in the above embodiment, actually, a switch device (for example, a transistor such as an IGBT) is connected in series to the normal line 5 and a controller such as an ECU controls the switch device. The switch device and the controller control the energization of the heater 3 and forcibly cut off the energization of the heater 3 when the temperature of the hot water tank 4 exceeds the allowable temperature range. Therefore, normally, the switch device and the controller prevent the temperature of the hot water tank 4 from exceeding the allowable temperature range.

  In the above embodiment, in addition to this, by providing the safety device 1 that is unlikely to cause malfunction or failure, the reliability of the DC current interruption at the time of abnormality is improved.

1 Safety device 2 DC power supply 3 Heater (load)
5 Line at normal time 6 Commutator 7 Resistance 8 Commutation line 10 Breaker 61 Fixed contact 62 Movable contact 63 Bimetal (thermal deformation member for commutation control)
66 Insulator 67 Protrusion 101 Fixed contact 102 Movable contact 103 Bimetal (thermal deformation member for interruption control)

Claims (8)

A safety device connected between a DC power source and a load,
A normal line connected to the DC power supply;
A commutation line connected in parallel to the normal line;
A resistance provided in the commutation line;
A commutator that shuts off the normal line and commutates the current flowing in the normal line to the commutation line;
Thermally deformable member for interruption control that is connected in series to the normal time line and the commutation line, or is connected in series to the commutation line and receives heat from the resistor directly or indirectly and reaches a critical temperature. A circuit breaker that is opened in response to deformation of the thermal deformation member for break control,
A safety device characterized by comprising: The safety device according to claim 1,
The safety device is connected to the positive electrode side of the load in the direction of current flow.
A safety device characterized by that. The safety device according to claim 1 or 2,
The commutator includes a heat deformation member for commutation control that directly or indirectly receives heat from the load and deforms or blows when the critical temperature is reached, and performs deformation or fusing of the heat deformation member for commutation control. The normal line is cut off and the current flowing in the normal line is commutated to the commutation line.
A safety device characterized by that. The safety device according to claim 3,
The commutator is provided in the normal line so as to be in parallel with the resistor.
A safety device characterized by that. The safety device according to claim 3,
The thermal deformation member for commutation control is a member that deforms when reaching a critical temperature,
The commutator is provided at a node between the normal line and the commutation line, and the DC power source and the normal line are connected by the deformation of the commutation control thermal deformation member. A state and a state in which the DC power source and the commutation line are connected are exclusively realized;
A safety device characterized by that. The safety device according to any one of claims 3 to 5,
The commutator is
A fixed contact;
A movable contact that receives the deformation of the thermal deformation member for commutation control and is separated from the fixed contact;
An insulator biased toward the movable contact by an elastic member;
With
One of the insulator and the movable contact has a protrusion,
The insulator is inserted between the movable contact and the fixed contact when the distance between the movable contact and the fixed contact is larger than the protrusion;
A safety device characterized by that. The safety device according to any one of claims 3 to 6,
The circuit breaker is
A fixed contact;
A movable contact that receives the deformation of the thermal deformation member for blocking control and is separated from the fixed contact;
An insulator biased toward the movable contact by an elastic member;
With
One of the insulator and the movable contact has a protrusion,
The insulator is inserted between the movable contact and the fixed contact when the distance between the movable contact and the fixed contact is larger than the protrusion;
A safety device characterized by that. The safety device according to claim 1 or 2,
The load is a heater disposed in a hot water tank,
The commutator is configured such that when the hot water tank reaches an upper limit temperature, when the heater reaches an upper limit temperature, when the water level in the hot water tank reaches a lower limit water level, or when the inclination of the hot water tank is an upper limit. When the angle is reached, the normal line is cut off, and the current flowing in the normal line is commutated to the commutation line.
A safety device characterized by that.