EP0630516B1 - 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

The invention relates to a polarized electromagnetic relay, which comprises:
a base;
a coil attached to the base, consisting of a coil body with a winding;
a core which axially penetrates the coil and protrudes from the coil body with its two ends;
at least one movable contact element and at least one fixed mating contact element, each of which is anchored laterally from the coil in the base;
an armature arranged above the coil, which is formed by two pole plates lying next to one another in one plane, a flux plate arranged parallel above the pole plates and a four-pole permanent magnet arrangement enclosed in layers between the pole plates and the flux plate, two poles of the same name of the permanent magnet arrangement having the same name, each with a pole plate and the two opposite poles are coupled to the flux plate.

A magnet system for such a relay is known from EP-A-34 811. In one embodiment, an armature in layered construction is formed from pole plates, a four-pole permanent magnet arrangement and a flux plate, which is however mounted centrally above the winding and bears bent pole shoes at both ends, which form working air gaps with each of the two core ends. Such a so-called H-armature system is magnetically very effective, but it has problems in production because, for example, a precisely aligned pin bearing in the area of the coil is difficult to manufacture and the system with two diagonally opposed air gaps and the one in between, precisely aligned Storage is mechanically overdetermined. The cited publication also does not provide any concrete information about a constructive solution to this Problems; in particular, it is also not shown how the magnet system in a relay is to be brought into relation to a contact arrangement and how the latter can then be actuated.

A polarized relay with a magnetically similar system is known from EP-A-72 976 and similarly from US-A-4,665,375. In this case, however, the four-pole permanent magnet with a layering of flux plate and pole plates is arranged firmly above the coil, while a rod-shaped armature is arranged in an axial opening of the coil body. Here, as in the system mentioned above, the four-pole permanent magnet above the coil winding gives very large pole faces, which is particularly advantageous for a long coil with a small cross-section. The use of a very flat magnet with a very small extension in the preferred direction, for example a ferrite magnet, results in a favorable use of space 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. Since the rod-shaped armature is arranged within the coil, its iron cross-section is limited in comparison to the inner diameter of the coil tube, because the armature must carry out 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 aforementioned 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 with a relay of the type mentioned, in which
two pole shoes formed as angled extensions of the pole plates enclose a first end of the core with the formation of working air gaps,
the armature is rotatably mounted in the vicinity of the second core end about an axis perpendicular to the coil axis;
the flux plate is magnetically coupled to the core and
the pole plates are provided with the permanent magnet arrangement and the flux plate to form the one-piece armature with a plastic covering, which forms a wall on each side of the coil and at least one actuating lug for actuating the movable contact element or the movable contact elements.

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 connection of the flux plate, the permanent magnet arrangement and the pole plates by means of plastic to form a one-piece anchor can be achieved either by a plug-in fastening of the parts in a plastic frame or, preferably, by extrusion-coating the metal parts with plastic. The actuating lugs are formed on the armature without any additional effort, with which at least one contact spring can then preferably be switched on both sides of the coil.

Further refinements are specified in the patent claims.

• Figur 1 ein erfindungsgemäß gestaltetes Relais in Einzelteilen,
• Figur 2 eine gegenüber Figur 1 etwas abgewandelte Ausführungsform eines Ankers,
• Figur 3 eine unterseitige Ansicht des Ankers von Figur 1 oder Figur 2,
• Figur 4 einen Schnitt durch ein leeres Gehäuse für ein Relais gemäß Figur 1 mit abgewandeltem Sockel,
• Figur 5 einen Sockel von Figur 4 in Draufsicht,
• Figur 6 bis Figur 9 jeweils verschiedene, gegenüber Figur 1 abgewandelte Magnetsysteme für ein erfindungsgemäßes Relais.

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, in addition to the coil assembly and the armature, a pair of contacts with the two on each side Contact springs 5 and 6 and the fixed counter-contact elements 7 and 8 are anchored. 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 bobbin 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 with it. Pole sheet sections 31a and 32a are formed on the top of each of the two pole pieces 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 respective opposite poles S and N are coupled on the top to a flux plate 34. This flux plate 34, which, like the two pole pieces 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 armature. A bore 34b is provided in the flow plate for mounting the armature on the journal 16. In addition, sheet metal studs 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 held together with the plastic walls 35 armature has a downwardly open cavity, 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 actuating 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, the coil assembly 1 is placed on the base during assembly, 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.

Figure 2 shows a slightly 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 ensure the sliding on the housing cap instead of the sheet-metal knobs 34c described above. Otherwise, the anchor according to FIG. 2 is constructed in the same way as the anchor from FIG. 1.

Figure 3 shows a view of the anchor of Figure 1 or Figure 2 from the bottom. 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 plate 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. In this case, as is also shown in FIG. 4, the cap 9 is also provided with additional partition walls 91 which overlap with the partition walls 46 of the base and thereby reinforce the insulation between the contact chambers and the magnet system with long creepage distances.

FIGS. 6 to 9 show modified embodiments for the magnet system which could therefore replace the magnet system from 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 specialist.

FIG. 6 shows again a system which, with minor changes, essentially corresponds to the system of FIG. 1. 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 magnetic flux generated by the permanent magnet 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 show a direction of flow in the case of excitation 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 towards the two pole shoes 31 and 32. It therefore overlaps 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 correspondingly asymmetrical magnetization of the permanent magnet can also achieve a monostable switching behavior.

7, the magnet system has been 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 can be obtained on the T-shaped coil core.

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 flow directly to the rear end of the core. Thus, while in the previous exemplary embodiments the excitation flux had to flow through the permanent magnet 33 to the flux 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 flux circuit is thus reduced. However, the permanent magnetic 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 characteristics.

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 at the front 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 gap. 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 relative to the associated counter-contact element 7 and 8 and rest on them 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 is more likely to tear open any glued contacts. The ACll switching capacity is greater here than with an inverted system. An additional advantage of self-pressure contacts is that the NC and NO contacts have the same mechanical requirements, so that the movements are the same, which ultimately leads to the same electrical 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 with an additional tungsten lead contact is formed.

Since in the system shown in FIG. 1 one contact closes while the other opens, a changeover contact 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 on 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 thanks 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 automatically increases the insulation distances. A bridge contact could also be realized with this structure.

Claims (9)

1. Polarized electromagnetic relay, comprising:
      a base (4);
      a coil (1) which is fastened to the base and comprises a coil former (11) with a winding (12);
      a core (2) which axially penetrates the coil (1) and the two ends (21, 22) of which protrude from the coil former (1);
      at least one movable contact element (5, 6) and at least one stationary mating contact element (7, 8), which are each anchored in the base (4) to the side of the coil (1);
      an armature (3) which is arranged above the coil (1) and is formed by two pole laminations (31a, 32a; 131a, 132a; 231a, 232a) situated next to one another in one plane, a flux lamination (34; 234) arranged in parallel over the pole laminations and a four-pole permanent magnet arrangement (33) which is enclosed like a layer between the pole laminations and the flux lamination, two unlike poles of the permanent magnet arrangement being coupled to one pole lamination each and the two opposite poles being coupled to the flux lamination, and, furthermore,
         two pole shoes (31, 32; 131, 132; 231, 232), which are formed as angled extensions of the pole laminations (31a, 32a; 131a, 132a; 231a, 232a), enclosing between them a first end (22) of the core (2), thereby forming operating air gaps, the armature (3) being supported in the vicinity of the second core end (21) in a manner which allows it to rotate about an axis which is perpendicular with respect to the coil axis;
         the flux lamination (34; 234) being magnetically coupled to the core (2), and the pole laminations (31a, 32a; 131a, 132a; 231a, 232a) together with the permanent magnet arrangement (33) and the flux lamination (34; 234) being provided with a plastic encapsulation in order to form the integral armature (3), which encapsulation forms one wall (35) in each case at both sides of the coil (1) and at least one actuating lug (36) for actuating the movable contact element or the movable contact elements (5, 6).
2. Relay according to Claim 1, characterized in that a bearing journal (16), which is perpendicular with respect to the coil axis and engages into a bearing recess (34b) in the armature (3), is moulded onto a coil flange (14) of the coil former (11) in the vicinity of the second core end (21).
3. Relay according to Claim 1 or 2, characterized in that sliding knobs (37; 34c) are provided on the underside and, if appropriate, on the top side of the end section, opposite the bearing arrangement, of the armature (3), by means of which knobs sliding movement is made possible on the base (4) and, if appropriate, on a housing cap (9).
4. Relay according to one of Claims 1 to 3, characterized in that the pole shoes (31, 32) are angled and offset at the ends in front of the coil in the direction of the axis, in order to form the operating air gaps with the first core end (22).
5. Relay according to one of Claims 1 to 3, characterized in that the pole shoes (131, 132) form operating air gaps which are in each case parallel to one another and to the side walls, and in that the first core end is widened in a T-shape in order to form the operating air gaps (Figures 7 to 10).
6. Relay according to Claim 4 or 5, characterized in that the pole shoes (231, 232) each form coupling sections (231b, 232b) to the side of and next to the coil, for the purpose of feeding the exciter flux back to the second core end.
7. Relay according to one of Claims 1 to 6, characterized in that the flux lamination (34) is coupled to the second core end.
8. Relay according to Claim 6, characterized in that the flux lamination (234) is coupled to the first core end (Figure 9).
9. Relay according to one of Claims 1 to 8, characterized in that the magnet system is insulated from sets of contacts (5, 6, 7, 8), which are arranged on both sides, by means of partitions (46; 91) which are moulded onto the base (4) and/or a cap (9).

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