JP2010040184A - Safety relay device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relay device with simplified constitution keeping state of its safety functions. <P>SOLUTION: The device is equipped with a pair of normally-open contacts 4a, 5a inserted into a power supply path 3 for a load 2, a pair of nomally-open contacts 8a, 8b inserted into a current supplying path for a pair of output relays 4, 5 which incorporate the pair of normally-open contacts, a self-retaining relay 8 in which the pair of normally-open contacts 8a, 8b for the current supplying path are incorporated, and a switching contact 20a which switches a driving current supplied from the relay to the self-retaining relay 8 or to the output relays 4, 5, and a starting relay 20 in which the switching contact 20a is incorporated. After the starting relay starts, the self-retaining relay starts by changing the switching contact to the self-retaining relay side, and then, the pair of normally-open contacts are closed. Further, by returning the switching contact of the switching relay to the output relay side, power is continuously supplied to the load. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a relay device incorporated in various electric devices and machine tools, and more particularly, to a safety relay device incorporated in an electric device and machine tool that is not allowed to fail and can ensure a high degree of safety in operation.

  In recent years, there has been a demand for improving the safety of the entire facility at the factory automation (FA) site. The safety relay shown in the electrical product incorporated in this facility is composed of a forcibly guided relay. In this forcibly guided relay, the contact on the other side remains open even when the contact on either the input side or the output side is welded.

  Specifically, at least two contacts of a normally open contact (a contact) and a normally closed contact (b contact) are operated by energizing the coil, and the normally open contact (a contact) is closed and normally closed. The contact (b contact) is opened.

  In this case, even if the coil is energized with the normally open contact (a contact) welded, in the normal relay, the open / close state of the normally closed contact (b contact) is indefinite, and the state is not guaranteed. In this forcibly guided relay, the normally closed contacts have an interval of, for example, 0.5 mm or more and guarantee an open state. Similarly, when the normally closed contact is welded and the coil is energized, the normally closed contact is welded, so it does not open, but the normally open contact does not close, and an interval of 0.5 mm or more is provided. Transition to the state of having. Thus, when one contact is welded, the other contacts are kept open.

  A safety relay device in which such a forced guide relay is incorporated is configured as shown in FIG. 10, for example.

  For example, first and second normally open contacts 4a and 5a are inserted in an electric power supply path 3 from an AC power source 1 such as AC 100V to an electric motor 2 of each factory facility. The DC 24V or AC 100V relay drive power supply 6 supplies drive current to the coil of the first output relay 4 via the relay path 7. In the relay path 7, one normally open contact 8a, one normally closed contact 9a, and a fuse 10 are inserted. The DC 24V or AC 100V relay drive power supply 11 supplies a drive current to the coil of the second output relay 5 via the relay path 12. In the relay path 12, one normally open contact 8b, one normally closed contact 9b, and a fuse 10 are inserted.

  The DC 24V relay drive power supply 13 supplies a starting current to the coil of the starting relay 9 via the initial starting path 14. An operation holding capacitor 15 is connected in parallel to the starting relay 9. A push button type reset switch 16 and three normally closed contacts 4b, 5b, and 8c are interposed in the initial activation path.

  The DC 24V relay drive power supply 13 supplies an operation holding current to the coil of the self-holding relay 8 via the holding path 17. The holding path 17 is provided with an external contact 18 and a normally open contact 9c that indicate a contact cutoff request to the fuse 10 and the electric motor 2 as a load. Furthermore, a normally open contact 8d is inserted in the bypass path 19 with respect to the normally open contact 9c of the holding path 17.

  The first output relay 4 includes a normally open contact 4a and a normally closed contact 4b, and the second output relay 5 includes a normally open contact 5a and a normally closed contact 5b. Further, normally closed contacts 9a, 9b and normally open contacts 9c are incorporated in the start relay 9 constituted by a forced guide type relay. Further, normally open contacts 8a, 8b, 8d and a normally closed contact 8c are incorporated in the self-holding relay 8 constituted by a forced guide type relay.

  The relay operation at the normal time of the safety relay device having such a configuration will be described with reference to the time chart of FIG. In FIG. 10, when the external contact 18 is in an open (off; low level) state, when the operator presses the reset switch 16, the starting current is supplied from the relay drive power supply 13 to the starting relay 9 via the initial starting path 14. Is done. As a result, the activation relay 9 is activated.

  However, even if the activation relay 9 is activated and the normally open contact 9c is closed, the external contact 18 is in an open (off; low level) state, so that the self-holding relay 8 is not energized. Therefore, the normally open contacts 8d, 8a and 8b remain open, and the first and second output relays 4 and 5 are not energized. Therefore, the normally open contacts 4a and 5a are open, and the motor (motor) 2 is It does not start.

  Next, when the external contact 18 is closed (on; high level), the reset switch 16 is pressed to activate the start relay 9 and the normally open contact 9c is closed. Is supplied, the self-holding relay 8 operates, the normally open contacts 8d, 8a, 8b are closed, and the normally closed contact 8c is opened. As a result, the energization of the starting relay 9 is cut off, the normally closed contacts 9a and 9b are closed, the first and second output relays 4 and 5 are energized, the normally open contacts 4a and 5a are closed, and the motor (motor) 2 is closed. Starts.

  For example, when a failure or the like occurs in a factory facility during operation of the electric motor 2 and the external contact 18 is opened (off; low level), the self-holding relay 8 is de-energized and the normally open contacts 8a and 8b are opened. Therefore, the first and second output relays 4 and 5 are cut off, and the normally open contacts 4a and 5a are opened, so that the power supply to the motor (motor) 2 is cut off.

  Next, in such a safety relay device, the operation of each contact when the normally open contact 9c of the start relay 9 constituted by a forced guide relay is welded will be described with reference to the time chart of FIG. .

  That is, since the normally open contact 9c of the starting relay 9 maintains the connection state by welding, the normally closed contacts 9a and 9b maintain, for example, the aforementioned interval of 0.5 mm or more. The output relays 4 and 5 are not energized. Accordingly, the normally open contacts 4a and 5a are in an open state, and the electric motor (motor) 2 is not started.

  Next, when a welding accident occurs at the normally closed contacts 9a and 9b of the start relay 9 constituted by a forced guide relay, the external contact 18 is closed (ON; as shown in the time chart of FIG. 11C). In the high level state, even if the reset switch 16 is pressed and the operation start operation for the electric motor 2 is started, the normally open contact 9c of the start relay 9 is not closed, for example, the above-mentioned interval of 0.5 mm is always maintained. The self-holding relay 8 is not activated. As a result, the normally open contact 8d remains open, and the first and second output relays 4 and 5 are not energized. Therefore, the normally open contacts 4a and 5a are open, and the electric motor (motor) 2 does not start.

  Therefore, even when a welding accident occurs at the contact of each relay incorporated in the safety relay device, the power supply to the motor 2 as a load is cut off, and the safety of the load can be ensured.

In addition to the above, such a relay configured with a forced guide relay is disclosed in Patent Document 1.
JP 2001-283704 A

  However, the safety relay device shown in FIG. 10 still has the following problems to be solved.

  In other words, in order to guarantee the high reliability of electrical equipment and mechanical equipment in which this safety relay device is incorporated, from the standpoint of fail-safe to the relay contact operation of this safety relay device itself, this safety relay device itself As a function that operates on the safe side even if any failure occurs, the above-described forced guide relay is employed in the two relays of the start relay 9 and the holding relay 8.

  When either one of the normally open contact and the normally closed terminal is welded, the other contact is always set to have an interval of 0.5 mm or more, for example. In order to realize the dimension of the distance in the contact constituted by the contact spring member and the structure and material for realizing the operation, the structure of the safety relay device becomes complicated, and the manufacturing cost is greatly increased.

  The present invention has been made in view of such circumstances, and by adopting a three-terminal switching relay that does not cause a welding accident between three terminals, some of the relays incorporated in the apparatus are high as an apparatus. An object of the present invention is to provide a safety relay device that can improve operability with a simple configuration and low cost while ensuring safety.

  In order to solve the above problems, a safety relay device according to the present invention includes a pair of normally open contacts inserted in a power supply path for a load and a current supply path for a pair of output relays in which the pair of normally open contacts are incorporated. A pair of normally open contacts inserted into the self-holding relay, a self-holding relay incorporating a pair of normally-open contacts of the current supply path, and a switching contact for switching the drive current of the relay supplied to the self-holding relay or the output relay And this switching contact is incorporated and has an activation relay.

  First, the activation relay is activated, the switching contact is switched to the self-holding relay side, the self-holding relay is activated, the pair of normally open contacts of the current supply path is closed, and then the start relay By returning the switching contact to the output relay side, power is continuously supplied to the load.

  By configuring in this way, among the many relays constituting this safety relay device, the starting relay that requires a particularly complete fail-safe function and the starting relay among the self-holding relays are made up of three-terminal switching contacts. Is adopted as the relay structure. Since a welding accident does not occur between the three terminals, it is not necessary to configure the activation relay with a forced-guide relay, and the activation relay may be formed with a normal structure.

  As a result, it is only necessary to create a forced-guide relay structure for self-holding relays, so that it is easy to configure, low cost, and easy to operate with high safety as a device. it can.

  According to another aspect of the present invention, a safety relay device includes a pair of normally open contacts inserted in a power supply path for a load, and a holding current supplied from a relay drive power source via a holding path. A self-holding relay composed of a forced guide relay for self-holding each closed state; an external contact that is inserted in the holding path and is opened in response to a power supply cutoff request to the load; A switching contact for switching a driving current from the relay driving power source to a pair of output relays incorporating the pair of normally open contacts and a starting path for the self-holding relay; and a start switch from the relay driving power source Start-up current is supplied via an initial start-up path in which is inserted, and the switching contact incorporated therein is switched to the start-up path side in response to the start-up switch operation. A normally-open contact inserted in the holding path, the contact state being changed by energization control via the starting path and the holding path for the self-holding relay. A pair of normally open contacts inserted in the relay path and a normally closed contact inserted in the initial activation path are provided.

  In the safety relay device configured as described above, when the operator presses the push button type start switch in a state in which the external contact that is opened in response to the power supply cutoff request to the load is closed, the start relay Is activated, and the normally open contact inserted in the relay path is closed. At the same time, since the start relay is cut off, the switching contact returns to the original relay path side, so that the output relay is started and power is continuously supplied to the load.

  And if the common terminal at the switching contact of the starting relay is welded to the normally open side terminal or the normally closed side terminal, the output relay is not energized or the self-holding relay is not activated, so the power supply to the load is surely cut off Is done. In this case, the common terminal at the switching contact of the start relay is not welded to the normally open side terminal and the normally closed side terminal at the same time. Therefore, it is not necessary to configure this activation relay with a forced guide relay.

  Therefore, since it is only necessary to create a forced-guide relay structure for the self-holding relay, it is possible to improve operability with a simple configuration and low cost while ensuring high safety as a device. .

  In another safety relay device of the present invention, the holding current is supplied from the first normally open contact and the second normally open contact inserted in the power supply path to the load and the relay drive power supply via the holding path. A self-holding relay composed of a forcibly guided relay for self-holding each closed state of the pair of normally open contacts, and in response to a request to cut off the power supply to the load, inserted in the holding path A first relay path for supplying a drive current from the relay drive power source to a first output relay in which the first normally open contact is incorporated, and an activation current for the self-holding relay. A first switching contact for switching to a starting path to be supplied, a second relay path for supplying a drive current from the relay drive power supply to a second output relay incorporating the second normally open contact, and a holding path And switch to A first switching current is supplied to the second switching contact and an initial starting path in which a starting switch is inserted from the relay drive power source, and is incorporated in response to the starting operation of the starting switch. A switching relay for switching to the starting path side, switching the second switching contact to the holding path side, and temporarily holding an energized state with a holding current input from the holding path; and a self-holding relay A normally open contact inserted in the holding path and a pair inserted in the relay path, the contact state of which is changed by energization control via the start path and the holding path for the self-holding relay. A normally open contact and a normally closed contact inserted in the initial starting path.

  In the safety relay device configured as described above, two switching contacts, a first switching contact and a second switching contact, are provided for the starting relay, and in addition to starting the self-holding relay, Has been implemented.

  In another safety relay device of the present invention, a holding current is supplied via a holding path from a pair of normally open contacts inserted in a power supply path for a load and a second relay driving power source, A self-holding relay composed of a forcibly guided relay for self-holding each closed state of the normally open contact, and inserted in the holding path, and opened in response to a power supply cutoff request to the load An external contact, a switching contact for switching a driving current from a first relay drive power source to a pair of output relays in which the pair of normally open contacts are incorporated, and a starting path for the self-holding relay; A starting current is supplied from a second relay drive power source through an initial starting path in which a starting switch is inserted, and the switching contact incorporated therein in response to an operation of turning on the starting switch A starting relay that is switched to the path side and a holding path for the self-holding relay, and based on a photoelectrically converted signal of the starting current that flows through the switching contact and the starting path, a starting current is obtained from the second relay driving power source. An activation control unit for supplying to the self-holding relay, and a contact state that is incorporated in the self-holding relay, and the contact state is changed by energization control via the activation path and the holding path for the self-holding relay. And a pair of normally open contacts inserted in the relay path, and a normally closed contact inserted in the initial activation path.

  In the safety relay device configured as described above, for example, when two types of relays having different driving voltages exist in the safety relay device, a control instruction between them is performed using a photocoupler. Yes. Therefore, the reliability of relay control can be greatly improved.

  In the present invention, the starter relay among the starter relay and the self-holding relay that requires a high-level fail-safe function has a relay structure that employs a switching contact composed of three terminals. As a result, it is only necessary to create a forced-guide relay structure for self-holding relays, so that it is easy to configure, low cost, and easy to operate with high safety as a device. it can.

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

(First embodiment)
FIG. 1 is a circuit configuration diagram of a safety relay device according to a first embodiment of the present invention. The same parts as those of the conventional safety relay device shown in FIG. 10 are denoted by the same reference numerals, and detailed description of the overlapping parts is omitted.

  First and second normally open contacts 4a and 5a are inserted in an electric power supply path 3 from an AC power source 1 such as AC 100V to an electric motor 2 of each factory facility. The DC 24V relay drive power supply 13 is connected to the common terminal c of the switching contact 20a incorporated in the start relay 20. The normally closed contact b side of the switching contact 20a is connected to the coils of the first and second output relays 4 and 5 via two relay paths 21a and 21b, respectively. Further, the normally open contact a side of the switching contact 20 a is connected to the self-holding relay 8 through the starting path 22. Normally open contacts 8a and 8b are inserted in the relay paths 21a and 21b, respectively.

  The DC 24V relay drive power supply 13 supplies a self-holding current to the coil of the self-holding relay 8 via the holding path 17. The holding path 17 is provided with an external contact 18 and a normally open contact 8d for instructing to open the fuse 10, the current interruption to the electric motor 2 as a load.

  Further, the DC 24V relay driving power supply 13 supplies a starting current to the starting relay 20 via the fuse 10, the external contact 18, and the initial starting path 14. A push button type reset switch 16 as an activation switch and three normally closed contacts 4b, 5b, and 8c are interposed in the initial activation path.

  A protective diode 23 is connected in parallel to each of the output relays 4 and 5, the start relay 20, and the self-holding relay 8. Furthermore, an LED 25 indicating that the self-holding relay 8 is energized is connected to both ends of the self-holding relay 8 via a resistor 24.

  The first output relay 4 includes a normally open contact 4a and a normally closed contact 4b, and the second output relay 5 includes a normally open contact 5a and a normally closed contact 5b. In addition, a switching contact 20 a is incorporated in the start relay 20. Further, normally open contacts 8a, 8b, 8d and a normally closed contact 8c are incorporated in the self-holding relay 8 constituted by a forced guide type relay.

  The operation in the normal state of the safety relay device of the first embodiment configured as described above will be described with reference to the time chart of FIG. In FIG. 2, when the external contact 18 is in an open (off; low level) state, even if the operator presses the reset switch 16, no current flows through the initial start path 14, so the start relay 20 does not start. Since the switching contact 20a also maintains the normally closed contact b side, the self-holding relay 8 is not energized. Accordingly, the normally open contact 8d remains open, and the first and second output relays 4 and 5 are not energized. Therefore, the normally open contacts 4a and 5a are open, and the electric motor (motor) 2 does not start.

  Next, when the operator presses the reset switch 16 while the external contact 18 is closed (on; high level), a current flows through the initial starting path 14, the starting relay 20 is activated, and the switching contact 20a is always on. It switches to the starting path 22 on the open contact a side. As a result, current is supplied from the relay drive power supply 13 to the self-holding relay 8 via the starting path 22, the self-holding relay 8 is started, the normally open contacts 8d, 8a, 8b are closed, and the normally closed contact 8c is opened. Is done. As a result, the energization of the starting relay 20 is cut off, the switching contact 20a is switched to the original normally closed contact c side, the first and second output relays 4 and 5 are energized, and the normally open contacts 4a and 5a are closed. The electric motor 2 starts up. In this case, the self-holding relay 8 is supplied with a holding current from the relay drive power supply 13 via the holding path 17. Therefore, even if the operator releases the reset switch 16, the self-holding relay 8 maintains the energized state.

  During operation of the electric motor 2, for example, when a failure or the like occurs in a factory facility and the external contact 18 is opened (off; low level), the self-holding relay 8 is de-energized, and the normally open contacts 8a and 8b are Since the first and second output relays 4 and 5 are cut off and the normally open contacts 4a and 5a are opened, the power supply to the motor (motor) 2 is cut off.

  In such a safety relay device of the first embodiment, an operation when an accident occurs in which the switching contact 20a of the start relay 20 is welded to the normally open contact a side will be described with reference to the time chart of FIG. .

  When the external relay 18 is closed (on; high level) and the reset switch 16 is pressed to start the start relay 20, the switching contact 20a is accidentally welded to the normally open contact a at the time indicated by the arrow in the figure. After that, the switching contact 20a does not return to the original normally closed contact b side even if the current to the activation relay 20 is interrupted.

  As a result, even if the starting current is supplied from the starting path 22 to the self-holding relay 8, the normally open contacts 8a, 8b, 8d are closed, the normally closed contact 8c is opened, and the current to the starting relay 20 is interrupted, the switching contact 20a does not return to the original normally closed contact b side. Therefore, since the first and second output relays 4 and 5 are not energized, the normally open contacts 4a and 5a are not closed, and the motor 2 is not started.

  Next, an operation when an accident occurs in which the switching contact 20a of the start relay 20 is welded to the normally closed contact b side will be described with reference to a time chart of FIG.

  When the external contact 18 is closed (on; high level) and the operator presses the reset switch 16 to activate the activation relay 20, the switching contact 20a is switched to the activation path 22 on the normally open contact a side, and is self-holding. The relay 8 is activated, the normally open contacts 8a, 8b, 8d are closed, the normally closed contact 8c is opened, the current to the activation relay 20 is interrupted, and the switching contact 20a returns to the original normally closed contact b side. At this time indicated by an arrow in the figure, an accident occurs in which the switching contact 20a is welded to the normally closed contact b side. Thereafter, even if the starting relay 20 is powered, the switching contact 20a is switched to the normally open contact a side. There is nothing.

  Therefore, once the motor 2 is started, after the external contact 18 is opened and the motor 2 is stopped, the motor 2 is not started even if the reset switch 16 is pressed.

  In the safety relay device of the first embodiment configured as described above, by adopting the switching contact 20a as the start relay 20, even if the switching contact 20a is on the normally closed contact b side or the normally open contact a side, for example. Even if welded, the electric motor 2 can be stopped reliably and the reliability of the safety relay device can be improved.

  Furthermore, the number of relays composed of forced-guide relays can be reduced to one self-holding relay 8, so that downsizing, simplification, and cost reduction can be achieved.

(Second Embodiment)
FIG. 4 is a circuit configuration diagram of the safety relay device according to the second embodiment of the present invention. The same parts as those in the safety relay device of the first embodiment shown in FIG.

  In the second embodiment, first and second normally open contacts 4a and 5a are inserted into an electric power supply path 3 from an AC power source 1 such as AC 100V to an electric motor 2 of each factory facility. Furthermore, the switching relay 20b, 20c is incorporated in the starting relay 20. The DC 24V relay drive power supply 13 is connected to the common terminal c of the first and second switching contacts 20b and 20c.

  The normally closed contact b side of the first switching contact 20b is connected to the coil of the first output relay 4 via the relay path 21a. Further, the normally open contact a side of the first switching contact 20 b is connected to the self-holding relay 8 through the activation path 22. The normally closed contact b side of the second switching contact 20c is connected to the coil of the second output relay 5 via the relay path 21b. The normally open contact a side of the second switching contact 20 c is connected to the activation relay 20 via the holding path 26. Normally open contacts 8a and 8b are inserted in the relay paths 21a and 21b, respectively.

  The DC 24V relay drive power supply 13 supplies a self-holding current to the coil of the self-holding relay 8 via the holding path 17. In the holding path 17, a fuse 10, an external contact 18, and a normally open contact 8d are inserted.

  Further, the DC 24V relay driving power source 13 supplies a starting current to the starting relay 20 via the fuse 10 and the initial starting path 14. A push button type reset switch 16 as an activation switch and three normally closed contacts 4b, 5b, and 8c are interposed in the initial activation path.

  The operation in the normal state of the safety relay device of the second embodiment configured as described above will be described with reference to the time chart of FIG. In FIG. 5, when the external contact 18 is in an open (off; low level) state, when the reset switch 16 is pressed, a current flows through the initial starting path 14 and the starting relay 20 is activated to switch the first and second switching. Since the contacts 20b and 20ca are switched to the normally open contact a side, the self-holding relay 8 is activated, the contacts 8a, 8b and 8d are closed, and the contact 8c is opened.

  When the operator releases the reset switch 16 in this state, the reset switch 16 is opened and the activation relay 20 is restored. At this time. If the external contact 18 is left open, the self-holding relay 8 returns to its original state, so that the contacts 8a and 8b are opened. Accordingly, since the first and second output relays 4 and 5 are not energized, the normally open contacts 4a and 5a are in an open state, and the electric motor 2 is not started.

  When the external contact 18 is closed, when the operator releases the reset switch 16, the self-holding relay 8 maintains the energized state on the holding path 17, so the contacts 8a and 8b are open. Not. Accordingly, since the first and second output relays 4 and 5 are energized, the normally open contacts 4a and 5a are closed and the electric motor 2 is started.

  When the external contact 18 is opened (off; low level) during operation of the electric motor 2, the energization of the self-holding relay 8 through the holding path 17 is cut off, and the normally open contacts 8a and 8b are opened. Since the first and second output relays 4 and 5 are cut off and the normally open contacts 4a and 5a are opened, power supply to the motor (motor) 2 is cut off.

  In such a safety relay device of the second embodiment, the operation in the case where an accident occurs in which the first switching contact 20b of the start relay 20 is welded to the normally open contact a side is described with reference to the time chart of FIG. I will explain.

  When the external contact 18 is closed (on; high level) and the operator presses the reset switch 16 to activate the start relay 20, the switching contact 20b is moved to the normally open contact a side at the time indicated by the arrow in the figure. After the welding accident occurs, the switching contact 20b does not return to the original normally closed contact b side even if the current to the starting relay 20 is interrupted.

  As a result, the starting current is supplied from the starting path 22 to the self-holding relay 8, the normally open contacts 8 a, 8 b, 8 d are closed, the normally closed contact 8 c is opened, even if the operator releases the reset switch 16, Even if the current is interrupted, the switching contact 20b does not return to the original normally closed contact b side. Therefore, since the first and second output relays 4 and 5 are not energized, the normally open contacts 4a and 5a are not closed, and the motor 2 is not started.

  Next, an operation when an accident occurs in which the switching contact 20b of the start relay 20 is welded to the normally closed contact b side will be described with reference to a time chart of FIG.

  When the external contact 18 is closed (on; high level) and the reset switch 16 is pressed to activate the activation relay 20, the switching contact 20b is switched to the activation path 22 on the normally open contact a side, and the self-holding relay 8 is activated. At the time of starting, the normally open contacts 8a, 8b, 8d are closed, the normally closed contact 8c is opened, and when the current to the start relay 20 is cut off by the operator opening the reset switch 16, the switching contact 20b Return to the normally closed contact b side. At this time indicated by an arrow in the figure, an accident occurs in which the switching contact 20b is welded to the normally closed contact b side. Thereafter, even if the starting relay 20 is powered, the switching contact 20b is switched to the normally open contact a side. There is nothing.

  Therefore, once the motor 2 is started and then the external contact 18 is opened and the motor 2 is stopped, the motor 2 is not started even if the operator presses the reset switch 16.

  Even in the safety relay device of the second embodiment configured as described above, by adopting two sets of switching contacts 20b and 20c for the activation relay 20, even if the switching contacts 20b and 20c are on the normally closed contact b side, Or even if it welds to the normally open contact a side, the electric motor 2 can be stopped reliably and the reliability of a safety relay apparatus can be improved.

  Accordingly, it is possible to achieve substantially the same operational effects as the safety relay device of the first embodiment.

(Third embodiment)
FIG. 7 is a circuit configuration diagram of the safety relay device according to the third embodiment of the present invention. The same parts as those in the safety relay device of the first embodiment shown in FIG.

  In the third embodiment, first and second normally-open contacts 4a and 5a are interposed in the power supply path 3 from the AC power source 1 such as AC 100V to the motor 2 of each factory facility. Further, the AC 100V relay drive power source 37 is connected to the common terminal c of the switching contact 20d incorporated in the start relay 20. The normally closed contact b side of the switching contact 20d is connected to the coils of the first and second output relays 4 and 5 via two relay paths 21a and 21b. The normally open contact a side of the switching contact 20d is connected to the starting path 27 for the self-holding relay 8 through a rectifying diode 36.

  The activation path 27 is connected to a photocoupler 28 including a light emitting element 29 and a light receiving element 30. The output signal of the photocoupler 28 is input to the activation control unit 31. The start control unit 31 including the transistor 33, the resistors 32 and 34, and the capacitor 35 first supplies the current output from the DC 24V relay driving power supply 13 to the holding path 17 to the self-holding relay 8.

  The DC 24V relay drive power supply 13 supplies a self-holding current to the coil of the self-holding relay 8 via the holding path 17. In the holding path 17, an external contact 18, a protective diode 36, and a normally open contact 8d that are opened by a current interruption command to the electric motor 2 as a load are inserted in the holding path 17. The activation control unit 31 is connected in parallel to the normally open contact 8d.

  Further, the DC 24V relay driving power supply 13 supplies a starting current to the starting relay 20 via the fuse 10 and the initial starting path 14. A push button type reset switch 16 as an activation switch and three normally closed contacts 4b, 5b, and 8c are interposed in the initial activation path.

  Protection diodes 23 are connected in parallel to the start relay 20 and the self-holding relay 8, respectively. Furthermore, an LED 25 indicating that the self-holding relay 8 is energized is connected to both ends of the self-holding relay 8 via a resistor 24.

  The first output relay 4 includes a normally open contact 4a and a normally closed contact 4b, and the second output relay 5 includes a normally open contact 5a and a normally closed contact 5b. In addition, a switching contact 20 d is incorporated in the start relay 20. Further, normally open contacts 8a, 8b, 8d and a normally closed contact 8c are incorporated in the self-holding relay 8 constituted by a forced guide type relay.

  The operation in the normal state of the safety relay device of the third embodiment configured as described above will be described with reference to the time chart of FIG. In FIG. 8, when the external contact 18 is in an open (off; low level) state, the reset switch 16 is pressed, a starting current flows from the DC 24V relay driving power supply 13 to the initial starting path 14, and the starting relay 20 is started. 20d switches to the normally open contact a side. As a result, a current flows through the activation path 27 and the photocoupler 28 becomes conductive. However, since the external contact 18 is in an open (off; low level) state, the transistor 33 of the activation control unit 31 is not conductive. Therefore, the self-holding relay 8 is not activated. Therefore, since the contacts 8a, 8b, 8d are not closed, the output relays 4, 5 do not operate. Therefore, since each contact 4a, 5a maintains an open state, the electric motor 2 does not start.

When the external contact 18 is closed (ON), the base potential of the transistor 33 of the activation control unit 31 is lowered by the conduction of the photocoupler 28 and the transistor 33 is turned on. Therefore, a drive current is supplied from the DC 24V relay drive power supply 13 to the self-holding relay 8 via the start control unit 31, and the self-holding relay 8 is started. As a result, the contacts 8a, 8b, and 8d are closed and the contact 8c is opened, so that the switching contact 20d returns to its original state, and the output relays 4 and 5 operate. Therefore, since each contact 4a, 5a is closed, the electric motor 2 starts.
When the external contact 18 is opened (off; low level) during operation of the electric motor 2, the self-holding relay 8 is de-energized and the normally open contacts 8a and 8b are opened, so that the first and second outputs Since the relays 4 and 5 are cut off and the normally open contacts 4a and 5a are opened, power supply to the electric motor (motor) 2 is cut off.

  In such a safety relay device of the third embodiment, an operation in the case where an accident occurs in which the switching contact 20d of the start relay 20 is welded to the normally open contact a side will be described with reference to the time chart of FIG. .

  When the external relay 18 is closed (on; high level) and the reset switch 16 is pressed to start the start relay 20, the switching contact 20d is accidentally welded to the normally open contact a at the time indicated by the arrow in the figure. Occurs. Therefore, after that, even if the operator releases the reset switch 16 (opens) and the current to the activation relay 20 is interrupted, the switching contact 20d does not return to the original normally closed contact b side. Absent.

  Therefore, the starting current from the starting path 27 conducts the photocoupler 28, operates the starting control unit 31, supplies the driving current to the self-holding relay 8, and the normally open contacts 8a, 8b, 8d are closed and normally closed. Even if the contact 8c is opened and the current to the activation relay 20 is interrupted, the switching contact 20a does not return to the original normally closed contact b side. Therefore, since the first and second output relays 4 and 5 are not energized, the normally open contacts 4a and 5a are not closed, and the motor 2 is not started.

  Next, an operation when an accident occurs in which the switching contact 20d of the start relay 20 is welded to the normally closed contact b side will be described with reference to a time chart of FIG. 9B.

  When the external contact 18 is closed (on; high level), the reset switch 16 is pressed, a starting current flows from the DC 24V relay driving power source 13 to the initial starting path 14, the starting relay 20 is started, and the switching contact 20d is always on. Switch to the open contact a side. As a result, the activation control unit 31 is activated via the activation path 27 and the photocoupler 28, current is supplied from the DC 24V relay drive power supply 13, and the self-holding relay 8 is activated. As a result, the contacts 8a, 8b, and 8d are closed and the contact 8c is opened, so that the switching contact 20d returns to its original state, and the output relays 4 and 5 operate. Therefore, since each contact 4a, 5a is closed, the electric motor 2 starts once. When the external contact 18 is opened, the self-holding relay 8 is stopped, so that the motor 2 is stopped due to the normal external contact 18.

  However, since the energization of the starting relay 20 is interrupted and the switching contact 20d is restored to the original position, it is welded to the normally closed contact b side. Even if the activation relay 20 is activated, the switching contact 20d is not switched to the activation path 27 side, and the self-holding relay 8 is not activated.

  In the safety relay device according to the third embodiment of the present invention configured as described above, for example, two types of relays having different drive voltages (DC 24v, AC 100V, etc. in the embodiment) are provided in the safety relay device. If it exists, the photocoupler 28 is used to instruct control between the two. Therefore, the reliability of relay control can be greatly improved.

  Further, in this safety relay device, by adopting a normal relay in which a normal switching contact is incorporated instead of a forced guide type relay as the starting relay 20, even if the switching contact 20d is the normally closed contact b side, Or even if it welds to the normally open contact a side, the electric motor 2 can be stopped reliably and the reliability of a safety relay apparatus can be improved.

  Accordingly, it is possible to achieve substantially the same operational effects as the safety relay device of the first embodiment.

1 is a circuit diagram showing a schematic configuration of a safety relay device according to a first embodiment of the present invention. The time chart which shows the operation | movement at the time of normal of the safety relay apparatus of 1st Embodiment The time chart which shows the operation | movement at the time of welding generation | occurrence | production of the safety relay apparatus of 1st Embodiment The circuit diagram which shows schematic structure of the safety relay apparatus concerning 2nd Embodiment of this invention. Time chart showing the operation of the safety relay device of the second embodiment at normal time The time chart which shows the operation | movement at the time of welding generation | occurrence | production of the safety relay apparatus of 2nd Embodiment The circuit diagram which shows schematic structure of the safety relay apparatus concerning 3rd Embodiment of this invention. Time chart showing the operation of the safety relay device of the third embodiment in the normal state Time chart showing operation at the time of welding occurrence of the safety relay device of the third embodiment Circuit diagram showing schematic configuration of conventional safety relay device Time chart showing the operation of the conventional safety relay device

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... AC power supply, 2 ... Electric motor, 3 ... Power supply path, 4 ... 1st output relay, 4a, 5a, 8a, 8b, 8d ... Normally open contact, 4b, 5b, 8c ... Normally closed contact, 5 ... 1st 2 output relays, 8 ... self-holding relay, 13, 37 ... relay drive power supply, 14 ... initial starting path, 16 ... reset switch, 17,26 ... holding path, 18 ... external contact, 20 ... starting relay, 21a, 21b ... Relay path, 20a, 20b, 20c, 20d ... Switching contact, 22, 27 ... Start path, 28 ... Photocoupler, 31 ... Start controller

Claims (4)

A pair of normally open contacts inserted in a power supply path for a load, a pair of normally open contacts inserted in a current supply path for a pair of output relays incorporating the pair of normally open contacts, and the current supply A self-holding relay incorporating a pair of normally open contacts of the road, a switching contact for switching the drive current of the supplied relay to a self-holding relay or an output relay, and an activation relay incorporating the switching contact,
First, the start relay is started, the switching contact is switched to the self-holding relay side, the self-holding relay is started, the pair of normally open contacts of the current supply path are closed, and then the start relay switching contact A safety relay device that continuously supplies power to a load by returning the power to the output relay side. A pair of normally open contacts inserted in the power supply path to the load;
A holding current is supplied from a relay drive power source via a holding path, and a self-holding relay configured by a forced guide relay for self-holding each closed state of the pair of normally open contacts;
An external contact that is inserted in the holding path and is opened in response to a power supply cutoff request to the load;
A switching contact for switching a driving current from the relay driving power source to a pair of output relays in which the pair of normally open contacts are incorporated and a starting path for the self-holding relay;
An activation relay for supplying an activation current from the relay drive power source through an initial activation path in which an activation switch is inserted, and switching the switching contact incorporated therein in response to an operation of turning on the activation switch to the activation path side When,
A normally open contact inserted in the holding path, which is incorporated in the self-holding relay, and the contact state changes by energization control via the start path and the holding path for the self-holding relay, A safety relay device comprising a pair of normally open contacts inserted and a normally closed contact inserted in the initial activation path. A first normally open contact and a second normally open contact inserted in a power supply path for a load;
A holding current is supplied from a relay drive power source via a holding path, and a self-holding relay configured by a forced guide relay for self-holding each closed state of the pair of normally open contacts;
An external contact that is inserted in the holding path and is opened in response to a power supply cutoff request to the load;
A first relay path for supplying a drive current from the relay drive power source to a first output relay incorporating the first normally open contact and a start path for supplying a start current to the self-holding relay are switched. 1 switching contact;
A second switching contact for switching a drive current from the relay drive power source to a second relay path and a holding path for supplying a second output relay in which the second normally open contact is incorporated;
A starting current is supplied from the relay driving power source through an initial starting path in which a starting switch is inserted, and the first switching contact incorporated therein in response to an operation of turning on the starting switch is set to the starting path side. An activation relay for switching and switching the second switching contact to the holding path side and temporarily holding an energized state with a holding current input from the holding path;
A normally open contact inserted in the holding path, which is incorporated in the self-holding relay, and the contact state changes by energization control via the start path and the holding path for the self-holding relay, A safety relay device comprising a pair of normally open contacts inserted and a normally closed contact inserted in the initial activation path. A pair of normally open contacts inserted in the power supply path to the load;
A holding current is supplied from the second relay driving power source via a holding path, and a self-holding relay configured by a forcibly guided relay for self-holding each closed state of the pair of normally open contacts;
An external contact that is inserted in the holding path and is opened in response to a power supply cutoff request to the load;
A switching contact for switching a driving current from the first relay driving power source to a pair of output relays in which the pair of normally open contacts are incorporated and a starting path for the self-holding relay;
A starting current is supplied from the second relay drive power source through an initial starting path in which a starting switch is inserted, and the switching contact incorporated therein in response to an operation of turning on the starting switch is set to the starting path side. An activation relay to switch,
An activation that is provided in a holding path for the self-holding relay and supplies a starting current from the second relay driving power source to the self-holding relay based on a photoelectrically converted signal of the starting current flowing through the switching contact and the starting path A control unit;
A normally open contact inserted in the holding path, which is incorporated in the self-holding relay, and the contact state changes by energization control via the start path and the holding path for the self-holding relay, A safety relay device comprising a pair of normally open contacts inserted and a normally closed contact inserted in the initial activation path.

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