Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
  • H01H9/10—Adaptation for built-in fuses
  • H01H9/106—Adaptation for built-in fuses fuse and switch being connected in parallel
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
  • H01H85/02—Details
  • H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
  • H01H85/041—Fuses, i.e. expendable parts of the protective device, e.g. cartridges characterised by the type
  • H01H85/048—Fuse resistors
  • H01H2085/0483—Fuse resistors with temperature dependent resistor, e.g. thermistor

Definitions

• the invention relates to an electrical fuse in which the power cut in the case of e.g. short-circuit-related overcurrent occurs through a melting element.
• Such fuses are e.g. also used to secure the high current supply to the vehicle electrical system.
• the input connection of the fuse is connected to the positive pole of the vehicle battery, the output connection of which is connected to the vehicle electrical system.
• Tripping behavior is a problem with fuses in general.
• the time that elapses before the fuse is triggered or until the melting element melts depends, among other things. depends on the size of the overcurrent. The larger this is, the shorter the release time.
• the tripping time also depends on the size of the fuse or the fuse value. With the same overcurrent, for example, a 70 A fuse trips faster than a 100 A fuse. Shortening the tripping time not only in the vehicle electrical system by using weaker fuses is not possible due to the associated risk of false tripping with conventional fuses.
• Another problem is that, for example, due to high-resistance line connections or a defective or insufficiently charged battery, the current flowing through the fuse is insufficient to melt the melting element or the current is too low to melt in a sufficiently short time to effect. The result is damage to the electrical system.
• a fuse with the features of claim 1.
• two are parallel, current paths connecting the input and output connection of the fuse, namely a main current path and a partial current path, a single melting element and a switch are provided, the melting element being arranged in the main current path and the switch being arranged in the partial current path.
• the switch is designed in such a way that it opens when predetermined limit values of the current flowing through the fuse and / or the temperature of the melting element are exceeded. While in conventional fuses with a fusible element the entire current flows through the fusible element, a current division takes place according to the invention.
• the current flowing via the main current path or via the melting element is reduced by the current flowing via the partial current path.
• a fuse with a lower fuse rating can be used in the main current path. If, for example, a 100 A fuse is necessary to protect a consumer or an electrical system, an 80 A fuse can be used if the partial current path is designed so that 20% of the total current flows through it. With the same current value, the tripping time is shorter with a weaker fuse than with a stronger fuse.
• the switch of the partial current path is now designed so that it opens in the event of an overcurrent caused, for example, by a short circuit in the electrical system. When the switch is open, all overcurrent flows through the fuse element.
• the fusible element can have a lower fuse value than is normally required due to the design according to the invention, the tripping time is shortened compared to the stronger fuse that is otherwise used. Ultimately, the same effect is achieved by a fuse according to the invention as when a fuse with a lower fuse value than required is used, but the risk of false tripping is eliminated.
• the switch in the partial current path can in principle be designed such that it opens either when a predetermined current value is exceeded or when a predetermined maximum temperature of the melting element is exceeded.
• both parameters - temperature and current value - can also be used simultaneously as criteria for opening the switch.
• Suitable switches are, for example, bimetallic switches, semiconductor switches or switching elements labeled “polyswitch”, the resistance of which increases suddenly when heated.
• the fuse and the switch arranged in the partial current path are arranged in a sandwich-like manner, in particular if the opening criterion for the switch is the temperature of the melting element, the switch and the melting element being in contact with one another with two contact surfaces and being in thermal contact.
• Such elements are preferably used that automatically close again after the melting element melts or after cooling.
• Such switches are e.g. the switches mentioned above, i.e. bimetallic switches, semiconductors and polyswitch elements.
• this has the following advantage: if the power supply to the vehicle electrical system has failed in the event of a short circuit, it is generally not possible for a non-specialist to replace the defective fuse with a new one. If only because the high-load safety devices of a motor vehicle are generally only accessible to the specialist personnel of a motor vehicle workshop. Because of the shutdown electrical system, important vehicle functions, such as the hazard lights or the like. disabled.
• the switch closes again after the fuse has blown, the on-board electrical system is supplied with power after the cause of the short circuit has been eliminated.
• the current flowing through the switch is reduced because of the increased resistance of the partial current path.
• equipment such as the hazard warning lights or an on-board telephone into operation.
• thermosensitive switch will open again after a certain time if an excessive current flows through the partial current path due to the short circuit.
• an uninterrupted supply of the vehicle electrical system is available, which is only the case with conventional fuse systems after the melting element has been replaced.
• a microprocessor can control the switch. For example, this does not have to be designed to be thermally sensitive.
• the temperature of the melting element can be determined by a Tapped thermal sensor and reported to the microprocessor, which controls the switch when a temperature limit is exceeded.
• the fuse comprises a current measuring device which transmits the value of the current total current flowing through the fuse to the microprocessor, which controls the switch when a limit current value is exceeded.
• the use of a microprocessor also has the advantage that it connects to the . Control and monitoring system of a vehicle can be connected.
• a microprocessor can be used, for example, to detect a temperature increase in the area of the input or output connection of the fuse with the aid of a thermal sensor. If the connections mentioned, for example as a result of corrosion, have too high a resistance and, accordingly, an elevated temperature, this can be communicated to the driver via a display on the dashboard, so that the driver is warned and can go to a workshop.
• FIG. 1 shows a schematic representation of a fuse according to the invention
• FIG. 2 shows an equivalent circuit diagram of the fuse when the switch is closed
• FIG. 3 shows an equivalent circuit diagram of the fuse when the switch is open
• Fig. 4 shows the triggering behavior of a fuse according to the invention
• Diagrams, and Fig. 5 is a circuit diagram of a fuse with microprocessor control.
• a fuse according to the invention comprises an input connection 1, an output connection 2, two current paths arranged in parallel between the two connections, namely a main current path 3 and a partial current path 3. current path or bypass 4, a melting element 5 and a switch 6.
• the melting element 5 is arranged in the main current path 3 and the switch 6 in the bypass 4.
• the melting element 5 and the switch 6 together form a sandwich-like component, wherein they adjoin one another with two contact surfaces 7, 8.
• this configuration serves to facilitate the heat transfer from the melting element 5 to the switch 6.
• the thermal coupling can take place in any way.
• the technical implementation of the switch is in principle arbitrary. It only has to be designed so that it opens when a limit current value or a limit temperature is exceeded.
• the fuse element 6 is intact in the initial state of the fuse and ensures a connection of the input connection 1 to the output connection 2 via the main current path 3.
• the switch 6, a thermosensitive switch of the above type is closed.
• the current l g ⁇ S taken from a current source 10, for example a vehicle battery is divided into the partial currents I ß yp ass and l u se. The division is in principle chosen so that the partial flow flowing through the bypass is less than the current flowing through the main current path 3.
• the switch 6 is a semiconductor element which is connected to the microprocessor 11, for example, via two signal lines 12, 13.
• the switch 6 is designed to be thermosensitive and is in direct thermal contact with the melting element 5.
• the status message about the current temperature of the melting element takes place via the signal line 12.
• the control of the switch 6 takes place via the signal line 13.
• the microprocessor is connected to the bus system 14 connected to the control and monitoring system of a motor vehicle. In this way, vehicle-specific data can be used as parameters for opening the switch 5.
• the switch 6 can be opened prophylactically in the event of a deployed airbag. The same applies if the vehicle is in a head position.
• thermal sensors are attached, with which an inadmissible heating of the connections 1, 2 as a result of an increase in resistance, for example due to corrosion, can be detected.
• thermo-sensitive switch it can be expedient not only to remove the amount of heat required in the case of a thermo-sensitive switch to heat it up, but also from the areas of the fuse, in particular the area of the input and output connections 1, 2, which are connected to it. If necessary, thermal contact between the switch and the fusible element can also be avoided entirely, in which case the mentioned connection areas or other areas of the fuse serve as a heat source for the switch.

Landscapes

• Fuses (AREA)
• Emergency Protection Circuit Devices (AREA)
• Glass Compositions (AREA)
• Surgical Instruments (AREA)
• Reciprocating, Oscillating Or Vibrating Motors (AREA)
• Electronic Switches (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7852839

Family Applications (1)

Country Status (7)

Families Citing this family (19)

Family Cites Families (24)

• 1997
  • 1997-12-20 DE DE19757026A patent/DE19757026A1/de not_active Withdrawn
• 1998
  • 1998-12-19 EP EP19980966375 patent/EP1040495B1/fr not_active Expired - Lifetime
  • 1998-12-19 US US09/581,962 patent/US6492747B1/en not_active Expired - Fee Related
  • 1998-12-19 WO PCT/EP1998/008340 patent/WO1999033079A1/fr active IP Right Grant
  • 1998-12-19 PT PT98966375T patent/PT1040495E/pt unknown
  • 1998-12-19 ES ES98966375T patent/ES2172260T3/es not_active Expired - Lifetime
  • 1998-12-19 DE DE59803106T patent/DE59803106D1/de not_active Expired - Fee Related
  • 1998-12-19 AT AT98966375T patent/ATE213358T1/de not_active IP Right Cessation

Non-Patent Citations (1)

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