WO1993018534A1 - Polarized electromagnetic relay - Google Patents

Abstract

A relay has a static core arranged inside the coil (12), and a swivelling armature arranged at one end of the coil that forms, together with two pole shoes (31, 32) at the other end of the coil, working air gaps with respect to one end of the core. The armature has two pole plate sections (31a, 32a) arranged in the extension of both pole shoes in a common plane outside of the coil and parallel to the axis of the coil, where they are coupled to one side of a four-pole permanent magnet. Both opposite poles of the permanent magnet are coupled to a flux plate which in turn forms a feedback to the core. With this system a polarized relay is obtained whose magnetic cross-sections can be very easily optimized and whose switching characteristic can be easily adjusted by balancing the permanent magnet. In addition, it is possible to easily separate the magnetic system from contact systems by means of appropriate insulating walls.

Description

Polarized electromagnetic relay

The invention relates to a polarized electromagnetic relay with a coil and a core arranged inside the coil, with both ends protruding from the coil, with two pole pieces, which enclose the first end of the core with the formation of working air gaps between them, with two pole sheet metal sections in Extension of the two pole shoes, which are arranged in a common plane outside the coil and parallel to the coil axis, with a flux plate lying parallel to the pole plate sections, which is magnetically coupled to the core, and with a four-pole permanent magnet arrangement, which is flat between the pole plate sections and the flux plate is arranged, two poles of the same name, each with a coupling section, and the two opposite poles being coupled to the flux plate.

Such a relay is known from EP-A-72 976. The four-pole permanent magnet next to or above the coil winding already gives very large pole areas, which is particularly advantageous in the case of a long coil with a small cross section. By using a very flat magnet with a very small extension in the preferred direction, for example ferrite magnets, an advantageous use of space is obtained since the magnet only slightly increases the height of the relay. Since the entire coil length is available for the length of the pole plates and the flux plate, the overlap area of these parts on the one hand and the pole surfaces of the permanent magnet on the other hand can be chosen to be optimally large, regardless of spatial restrictions.

In the known system, the rod-shaped coil core in the coil serves as an anchor. However, its iron cross section is limited compared to the inside diameter of the coil tube, because the armature must perform its switching movement within the coil, that is, an air gap must be kept free for the armature stroke.

The object of the present invention is to make the above-mentioned relay principle usable for switching higher currents and voltages. For this purpose, the magnetic circuit in particular should be optimized so that larger contact forces can also be generated for higher currents or voltages. At the same time, the construction should be chosen so that good insulation between the magnetic circuit and the contact system can be achieved.

According to the invention, this object is achieved in a relay of the type mentioned at the outset in that the core is arranged in a fixed manner in the coil and in that the pole shoes form an armature with the permanent magnet arrangement and the flux plate, which anchors in the vicinity of the second core end ¬ axis vertical axis is rotatably mounted.

Since the coil core is fixed in the relay according to the invention, its magnetic cross section can be made optimally large. This also optimizes the coil's efficiency.

The flux plate, the permanent magnet arrangement and the pole pieces are expediently connected to a one-piece anchor by means of plastic. This can be achieved by plug-fitting the parts in a plastic frame or preferably by injecting the metal parts with plastic. Actuating lugs can also be formed on the armature with which at least one contact spring is switched on both sides.

Further refinements are specified in the patent claims. The invention is explained in more detail below using exemplary embodiments with reference to the drawing. It shows

1 shows a relay designed according to the invention in individual parts,

FIG. 2 shows an embodiment of an anchor that is somewhat modified compared to FIG. 1,

FIG. 3 shows an underside view of the armature from FIG. 1 or FIG. 2,

FIG. 4 shows a section through an empty housing for a relay according to FIG. 1 with a modified base,

FIG. 5 shows a base from FIG. 4 in plan view,

6 to 9 each show different magnetic systems modified for FIG. 1 for a relay according to the invention.

The relay shown in FIG. 1 in an exploded view has a coil assembly 1 with a core 2 inserted along the axis, an armature 3 pivotably mounted on the coil assembly and a base 4, in which next to the coil assembly and next to the Anchors are anchored on both sides of a pair of contacts with the two contact springs 5 and 6 and the fixed mating contact elements 7 and 8. A cap 9 (FIG. 4), not shown in FIG. 1, forms a housing with the base 4.

Specifically, the coil assembly 1 consists of a coil body 11 with a winding 12, which is applied between two flanges 13 and 14. The flange 13 has on its underside a nose 15 which engages in a recess 41 in the base 4. A bearing pin 16 for the armature 3 is formed on the flange 14 on the upper side. Coil connecting pins 17 are also anchored in the flange 14. The Spu Steering element 11 has an axial cavity 18 into which the core 2 is inserted. This core has at its rear end in the region of the coil flange 14 a coupling section 21 with an enlarged cross section, which enables a better flow transition between the armature and the core.

The armature 3 contains, as an assembly, two ferromagnetic pole shoes 31 and 32 which, after assembly, enclose the front end 22 of the core and form a double working air gap therewith. Pole sheet sections 31a and 32a are formed on the top of each of the two pole shoes and bent into a common plane in order to ensure a large-area coupling to a permanent magnet 33. This permanent magnet 33 is magnetized with four poles, so that it turns to the two pole plate sections 31a and 32a, respectively opposite poles N and S, while the associated counterpoles S and N are coupled to a flux plate 34 on the upper side. This flux plate 34, which, like the two pole shoes 31 and 32, is made of ferromagnetic material, lies on the permanent magnet 33 over a large area after assembly. It has a coupling section 34a at the rear end which, after assembly, is brought as close as possible to the coupling section 21 of the core - while ensuring the mobility of the anchor. A bore 34b is provided in the flow plate for mounting the armature on the bearing journal 16. In addition, sheet metal knobs 34c are formed on the front end of the flow plate, which allow sliding contact between the armature and the housing cap to ensure the mobility of the armature.

As shown in Figure 1, the pole plates 31 and 32, the permanent magnet 33 and the flux plate 34 are stacked on one another and then coated with plastic walls 35 on the sides such that the armature 3 shown in Figure 1 as a closed assembly is formed. This armature held together with the plastic walls 35 has a cavity which is open at the bottom, so that the armature is placed on the coil assembly 1 and on the Bearing pin 16 can be stored. Actuating lugs 36 are also formed laterally on the plastic walls 35 and are used to actuate the contact springs 5 and 6, which are prestressed inwards in each case. In addition, 35 sliding knobs 37 are formed on the underside of the plastic walls, which slide on the base 4 during the switching movement of the armature and thus keep the necessary actuation force low.

The contact springs 5 and 6 each have contact pieces 51 and 61, while the counter-contact elements 7 and 8 also have contact pieces 71 and 81. The contact springs 5 and 6 are each connected, for example welded, to a spring support or connecting element 52 or 62, which are respectively inserted into openings 42 in the base when the relay is installed. Openings 43 are also provided in the base for the mating contact elements 7 and 8. Furthermore, during assembly, the coil assembly 1 is placed on the base, the coil connection pins 17 being inserted into corresponding openings 44. As already mentioned, the armature is placed on the coil assembly, so that the bearing pin 16 reaches the bearing bore 34b. Then the cap 9 is put on according to FIG. 4. The housing can then be sealed on the underside by means of a casting compound 10 in the usual way, as is also indicated in FIG. 4.

FIG. 2 shows a somewhat modified embodiment of the anchor. In this case, the flow plate 34 is made somewhat narrower, while the side walls 35 are extended upwards. In this case, sliding knobs 35a are also formed on the upper side of the side walls 35, which instead of the previously described sheet-metal knobs 34c ensure sliding on the housing cap. Otherwise, the anchor according to FIG. 2 is constructed in the same way as the anchor from FIG. 1.

FIG. 3 shows a view of the anchor of FIG. 1 or of FIG. 2 from the underside. From this it can be seen that the side walls 35 each have only a small thickness, so that a large inner cavity 38 remains, in which the coil of the relay comes to rest. In this view from below, the pole sheet sections 31a and 32a and in the central part of the permanent magnet 33 are also visible.

FIG. 4 shows a section through the empty housing, consisting of base 4 and housing cap 9, that is to say without a magnet system and contacts. The base 4 according to FIG. 4 is somewhat modified compared to FIG. 1. It also has raised side walls 45 and insulating intermediate walls 46 which separate the magnet system (coil assembly 1 and armature 3) arranged on the inside from the contact systems arranged on the side. This base from FIG. 4 is shown again in a top view in FIG. The intermediate walls 46, which each have recesses 47 for the passage of the actuating lugs 36, can also be clearly seen. In this way, specially separated contact chambers 48 are formed. As is further shown in FIG. 4, in this case the cap 9 is also provided with additional partition walls 91 which overlap with the intermediate walls 46 of the base and thereby the insulation between the contact chambers and the magnet system with long creepage distances reinforce.

6 to 9 show modified embodiments for the magnet system, which could therefore replace the magnet system of FIG. 1, consisting of the coil assembly 1 and the armature 3. Insofar as these are only schematic representations, the complete constructions can easily be supplemented by a person skilled in the art.

FIG. 6 shows again a system which essentially corresponds to the system of FIG. 1 with minor changes. Only the pole sheet sections 31a and 32a are somewhat shortened compared to the illustration there. The magnetic fluxes are shown in FIG. 6 as well as in the following figures, the excitation flux generated by the coil with FE and the permanent magnet generated by the permanent magnet. gnetfluss are designated with FD. In the case of the permanent magnetic flux FD, the arrows indicate the flow direction predetermined by the polarization of the permanent magnet according to FIG. 1. For the excitation flow FE, the arrows in FIG. 6 show a direction of flow when excited with a specific current direction. In this case, the excitation flow at the front end of the core flows through the working air gaps on both sides in the direction of the two pole shoes 31 and 32. It is therefore superimposed with the permanent magnetic flux FD in the right working air gap, but negatively in the left working air gap. This means that in the illustration in FIG. 6 the armature is attracted to the core via the pole shoe 32. When the excitation flow FE is reversed, the armature switches in the opposite direction. A monostable switching behavior can also be achieved by appropriately asymmetrical magnetization of the permanent magnet.

7, the magnet system is modified such that the core 120 is widened in a T-shape at its front end, that is to say it has side legs 121 and 122, respectively. Appropriately adapted pole pieces 131 and 132 thus each form working air gaps in the side wall area. The extensions of the two pole pieces 131 and 132 are then coupled to the permanent magnet 33 again as pole sheet sections 131a and 132a. With such a construction, larger magnetic cross sections and coupling surfaces on the T-shaped coil core can be obtained.

In the embodiment according to FIG. 8, a T-shaped widened coil core 220 with side legs 221 and 222 is again provided. In this case, however, the pole shoes 231 and 232 have not only pole sheet sections 231a and 232a, but also additional coupling sections 231b (not visible) and 232b, which couple the excitation flux directly to the rear end of the core. Thus, while in the previous exemplary embodiments the excitation flow had to flow through the permanent magnet 33 to the flow plate 34, it becomes according to FIG. 8 directly coupled to the core via a portion of the ferromagnetic pole pieces. The magnetic resistance for the excitation flow circuit is thus reduced. However, the permanent magnet flux is also partially short-circuited in this way, so that a higher magnetization of the permanent magnet 33 is required. An optimization of the cross sections and air gaps is therefore necessary in accordance with the desired characteristic.

Finally, in the example in FIG. 9, a T-shaped core 220 and pole shoes 231 and 232 are constructed in the same way as in the example in FIG. 8. In turn, they have pole plate sections 231a and 232a and coupling sections 231b and 232b for coupling to the rear end of the core. Compared to the previous example, a modified flow plate 234 is now provided, the coupling section 234a of which is bent on the front side of the armature. The excitation flow from the flux plate to the pole plate sections is thus not returned in the area of the armature bearing, but in the area of the working air gaps. In this case, too, the excitation flux FE does not go through the permanent magnet 33, but directly to the pole shoes 231 and 232 via lateral air gaps.

In this case too, the permanent magnet 33 is partially short-circuited, so that a high magnetization of the permanent magnet is also required here. In this case, too, cross sections and air gaps must be optimized.

As can be seen from FIG. 1, the contacts are designed as self-pressure contacts, that is to say that the contact springs 5 and 6 are each preloaded with respect to the associated counter-contact element 7 and 8 and rest on the latter in the idle state. The magnet system therefore only has the function of opening the contacts. However, the safe opening of the contacts is the most critical condition at high currents. The opening process is more effective for self-pressure contacts because the already accelerated magnet system at the end of its switching movement strikes the contact springs and, with a higher probability, also tears open possibly glued contacts. The ACll switching capacity is larger here than with an inverted system. An additional advantage of self-pressure contacts is that the normally closed contacts and the normally open contacts have the same mechanical prerequisites and therefore the same movement sequences, which ultimately also achieves the same electrical service life under load. The contacts can be adjusted using a purely mechanical spring bend with the appropriate gauges. The spring force of the self-pressure contact springs can also be used to reset the relay armature. In special cases, the contact structure could also be changed so that a normally open contact is formed with an additional tungsten lead contact.

Since, in the system shown in FIG. 1, one contact closes while the other opens, a changeover can be formed by appropriate wiring. For this purpose, the self-pressure principle creates a kind of positive guidance if the magnet system has a certain, tolerated course. This ensures that when one of the contacts is welded, the other cannot close, since the magnet system is blocked by the welded contact. The separate chambers also ensure that in the event of a spring break in one of the contacts, uncontrolled bridging by loose metal parts on the other contact cannot take place.

The separation of the two contacts in separate chambers to the right and left of the magnet system generally prevents the influence of the erosion products of one contact on the switching behavior of the other. The dielectric strength of the relay is also safer due to this contact separation due to the larger distances.

It would also be conceivable to arrange the magnet system asymmetrically on the base in order to have a larger space on one side for only one contact, either in the opener or closer configuration to build. The contact and spring dimensions can thus be increased for higher switching capacities. This increases the insulation distances automatically. A bridge contact could also be realized with this structure.

Claims

Claims 1. Polarized electromagnetic relay with a coil (12) and a core (2) arranged inside the coil, with both ends protruding from the coil, with two pole pieces (31, 32) forming the first end (22) of the core of working air gaps between them, with two pole plate sections (31a, 32a), which are arranged in a common plane outside the coil and parallel to the coil axis, with a flux plate (34) lying parallel to the pole plate sections, the is magnetically coupled to the core (2) and with a four-pole permanent magnet arrangement which is arranged flat between the pole plate sections (31a, 32a) and the flux plate (34), two poles of the same name, each with a coupling section, and the two opposite poles are coupled to the flux plate, characterized in that the core (2) is fixed in the coil (12) and that the pole pieces (31, 32) with the duration magnet arrangement (33) and the flux plate (34) form an armature (3) which is rotatably mounted in the vicinity of the second core end (21) about an axis perpendicular to the coil axis. 2. Relay according to claim 1, so that the flux plate (34) is connected to the permanent magnet (33) and the pole pieces (31, 32) by means of plastic (35) to form a one-piece anchor (3). 3. Relay according to claim 1 or 2, so that the actuating lugs (36) for actuating at least one contact spring (5, 6) are connected on both sides to the armature (3). 4. Relay according to one of claims 1 to 3, characterized in that on a coil flange (14) in the vicinity of the second core end (21) a bearing pin (16) is formed which is perpendicular to the coil axis and engages in a bearing recess (34b) of the armature (3). 5. Relay according to one of claims 1 to 4, characterized in that on the opposite end of the armature bearing (3) on the underside and optionally on the top slide knobs (37j 34c) are seen by means of which a sliding movement a base (4) and optionally on a housing cap (9) is made possible. 6. Relay according to one of claims 1 to 5, characterized in that the pole shoes (31, 32) with their air gap sections (31a, 32a) are angled on the end face from the spool to the axis and bent to the first core end (22nd ) to form the working air gap. 7. Relay according to one of claims 1 to 5, characterized in that the with their Polblechab¬ sections (131a, 132a) above the coil pole shoes (131, 132) each form parallel to each other and to the side walls standing working air gaps and that the first core end to form the working air gap is widened in a T-shape (FIGS. 7 to 10). 8. Relay according to claim 6 or 7, so that the pole shoes (231, 232) form each side of the coil coupling sections (231b, 232b) for returning the excitation flow to the second core end. 9. Relay according to one of claims 1 to 8, d a d u r c h g e k e n n z e i c h n e t that the flux plate (34) is coupled to the second core end. 10. Relay according to claim 8, characterized - shows that the flux plate (234) is coupled to the first core end. 11. Relay according to one of claims 1 to 10, characterized in that the magnet system by partitions (46; 91) which are integrally formed on a base (4) and / or a cap (9) of contact sets (5 , 6, 7, 8) is isolated.