EP0118040B1 - Electromagnetic relay with a swivel-mounted armature within the bobbin - Google Patents

Abstract

An electromagnetic relay includes an armature 1 supported in a central longitudinal bore 12 of a one-part bobbin 2 by means of a bearing which includes a first pair of curved bearing surfaces 1a, 1b, formed on the armature 1 and engaging a second pair of supplementarily curved bearing surfaces 2a, 2b, formed in the bore walls. The first bearing surfaces 1a, 1b may be either cylindrical in which case cylindrical second bearing surfaces 2a, 2b are formed in ribs 2c, 2d projecting inwardly from opposite bore walls, or spherical in which case spherical second bearing surfaces are formed directly in opposite bobbin walls.

Description

The invention relates to an electromagnetic relay of the type specified in the preamble of claim 1.

Such a relay is known from DE-B-2 334 838. In the relay described there, bearing surfaces are formed in the inside of the coil body, in which the armature is mounted on eccentric disks by means of pins protruding from its side surfaces. The eccentric discs serve to avoid air gaps, which can occur at one of the two ends in the end positions of the armature mounted in the center. However, the eccentric disks involved in the mounting of the armature relative to the coil body represent additional components which impose additional tolerances in the mounting and thus impair the switching accuracy of the relay.

From DE-B-2 318 812 an electromagnetic relay is known, in which the armature is also mounted in the interior of the coil body via journal bearings, but without additional components. Here, too, the good efficiency that is given in principle with such an arrangement is achieved, and high shock and vibration resistance can also be achieved at the same time. However, in order to form the counter bearing required in the coil former, it is expressly described as two parts. This results in the difficulty that a high electrical dielectric strength cannot be achieved between the relay coil and the armature or the contacts which are likewise arranged within the coil body.

Another relay known from DE-C-2 461 884 has a one-piece coil body designed as a protective tube with an armature arranged therein. The armature is live and acts as a bridge contact with two fixed contacts in each of the two coil body flanges. When shifting, it rotates around its center. A cylindrical pin is provided in the center for its storage, which rests in the protective tube with tolerance-compensating play. This type of storage prevents accidental contact of the armature with the opposite fixed contact. It is also easy to manufacture, although it must be accepted that the anchor remains displaceable in its longitudinal direction. The relay is therefore less suitable for applications in which shock or vibration occurs or precise response values are required.

The invention has for its object to provide an armature bearing in a relay of the type mentioned, which is afflicted with the smallest possible tolerances, which simultaneously enables the two armature ends to abut their opposite poles or contact or actuating pieces at the same time, and prevents longitudinal displacement of the armature.

According to the solution to this problem according to the invention specified in claim 1, in a one-piece bobbin without great manufacturing effort, a shape-specific, reproducible bearing within narrow tolerances is obtained, which ensures the desired g ^l - uniform contact of the armature ends with opposite poles or fixed contacts. The trough-shaped counter bearing surfaces, which are preferably formed in two mutually opposite walls within the coil body, are produced, for example, during the injection process of the coil body by a correspondingly shaped insert or stamp. The depth of the cylindrical or spherical counter bearing surfaces is chosen so that the elasticity of the material of the side walls of the coil body allows the insertion or stamp to be easily removed from the mold.

The embodiment of the invention according to claim 2 results in a particularly secure anchor bearing, since it can no longer move laterally. The additional bearing surfaces provided on the side walls of the armature can then be dome-shaped, in which case they practically only touch the wall of the bobbin bore and do not significantly increase the bearing friction.

In the advantageous development of the invention according to claim 3, the greatest possible mechanical stability is achieved by symmetrical formation of the armature, which performs a pure rotary movement about the relevant axis of gravity.

The further preferred embodiment of the invention according to claim 4 ensures that the armature is secured in both longitudinal directions without the need for engaging portions in the coil body. This enables the bobbin to be removed from the mold even in the case of relatively inelastic material, for example by inserting two inserts into the bobbin from opposite end faces which meet in the middle of the bobbin. The use of thermosetting material thus enabled results in a relay that can also be used at higher ambient temperatures and is more resilient.

The bearing element provided in the development according to claim 5 can be integrally formed on the armature by partial sheathing or can accommodate the armature as a separate insulating part.

If the armature is constructed from two parts according to the embodiment according to claim 6, there is the possibility of creating a multi-contact relay in which sufficient creepage distances can be realized between the two armature parts by appropriate dimensioning of the bearing element. In this case, the development of the invention according to claim 7 is advantageous in order to ensure sufficient synchronism in the movement of the two anchor parts. With such a divided Anchors have a bridge contact at each anchor end. Since a magnetic field is formed around each current-carrying contact bridge, the field lines of which in the contact area run perpendicular to the direction of movement of the contact bridge, a magnetic blow-out effect for an arc occurring during the switching process is also achieved.

The measures mentioned in claims 8 to 10 lead to a stiffening of the coil body side walls, the elasticity required for inserting the armature being retained in the region of the ribs. When assembling, the elastic material deformation occurs essentially only in the area of these ribs. The tapering of these ribs towards the coil body ends facilitates the insertion of the armature.

The measure of claim 11 has the effect that the coil winding does not exert any pressure on the bearing which would otherwise occur as a result of heating.

Various exemplary embodiments of the invention are described below with reference to the drawings.

• Fig. 1 einen Schnitt durch einen Spulenkörper mit eingesetztem Anker entlang der Linie C-D von Fig. 2;
• Fig. 2 einen Schnitt entlang der Linie A-B von Fig. 1;
• Fig. 3 einen Schnitt durch eine weitere Ausführungsform der Erfindung entlang der Linie G-H von Fig. 4;
• Fig. 4 einen Schnitt entlang der Linie E-F von Fig. 3;
• Fig. 5 einen Schnitt durch eine weitere Ausführungsform der Erfindung entlang der Linie L-M von Fig. 6 für Doppelankeranordnungen;
• Fig. 6 einen Schnitt entlang der Linie I-K von Fig. 5;
• Fig. 7 einen Schnitt entlang der Linie N-0 von Fig. 5;
• Fig. 8 einen Schnitt durch eine weitere Ausführungsform der Erfindung entlang der Linie R-S von Fig. 9 mit einem separaten Lagerkörper;.
• Fig. 9 einen Schnitt entlang der Linie P-Q von Fig. 8;
• Fig. 10 einen Schnitt entlang der Linie T-U von Fig. 8 und
• Fig. 11 eine perspektivische Darstellung einer Lagerkörperhälfte.

In it show:

• 1 shows a section through a coil body with an inserted armature along the line CD of Fig. 2.
• FIG. 2 shows a section along the line AB of FIG. 1;
• 3 shows a section through a further embodiment of the invention along the line GH of FIG. 4;
• Fig. 4 is a section along the line EF of Fig. 3;
• FIG. 5 shows a section through a further embodiment of the invention along the line LM from FIG. 6 for double anchor arrangements; FIG.
• FIG. 6 shows a section along the line IK from FIG. 5;
• Fig. 7 is a section along the line N-0 of Fig. 5;
• 8 shows a section through a further embodiment of the invention along the line RS from FIG. 9 with a separate bearing body.
• Fig. 9 is a section along the line PQ of Fig. 8;
• Fig. 10 is a section along the line TU of Fig. 8 and
• Fig. 11 is a perspective view of a bearing body half.

According to FIG. 1, an armature 1 is held in a coil former 2 made of plastic in that bearing catches 1 a and 1 b, which are spherical in shape and extend away from the anchor 1, engage in corresponding bearing troughs 2a and 2b which engage in the coil former 2 are molded. In this way, the armature 1, which has at its free ends 11 and 11 'contact surfaces 1c, 1d and 1c', 1d ', is mounted so as to be pivotable about an axis x (FIG. 2), so that the contact surfaces interact with counter-contacts (not shown) can. The coil body 2 is rectangular in cross section and has in its central region a cavity 12 which extends from the end face 13 of the coil body 2 through it to the opposite end face 13 'and into which the armature 1 is inserted.

The anchor cross section in all the illustrated embodiments is, but not necessarily, rectangular and is delimited by left and right side walls 17, 18 and by lower and upper walls 9. The walls 17, 18, 9 of the armature 1 face the inner sides of the left and right side walls 2e, 2k and the upper and lower side walls 2f of the coil body 2. The walls 2e, 2k and 2f enclose the cavity 12 in the coil former, and their ends are designed as coil former flanges defining the end faces 13 and 13 '.

One rib 2c, 2d extends from the upper and the lower wall 2f into the cavity 12. As can be seen from FIG. 2, the rib 2c is narrow relative to the total width of the upper wall 2f. The same applies to the rib 2d, in which, like in the rib 2c, the bearing troughs 2b and 2a are formed. The outer sides of the upper and lower walls 2f have trough-shaped depressions 2g, the wall thickness of the upper and lower walls 2f tapering towards the central region where the ribs 2d and 2c are formed. The formation of the recesses 2g ensures that there is still a certain elasticity of the walls 2f if a relatively hard-elastic plastic is chosen for the coil former. This elasticity is necessary for the insertion of the armature 1 into the cavity 12, that is to say the insertion of the bearing catches 1a, 1b into the bearing troughs 2a and 2b. To facilitate the insertion process, the height of the ribs 2c and 2d along the cavity 12 is not uniform, but tapers from the center thereof to the end walls 13. The ribs 2c, 2d can run down to the normal wall dimension before the end walls are reached.

The arms 16 and 16 'of the armature 1 also taper towards their ends. The central region 15 has the spherical bearing catches 1a and 1b, which in this embodiment extend over the entire width b of the armature 1 from the left side wall 17 to the right side wall 18. These bearing catches 1 a and 1 b are easy to manufacture and robust as elevations extending cylindrically with respect to the pivot axis x, so that there is no danger of breaking off as in the case of anchor pins. In the partially cylindrical configuration of the bearing catches 1a, 1b according to FIGS. 1 and 2, the cylinder axis coincides with the swivel axis x. The bearing troughs 2a have a complementary, partially cylindrical design. 2b on. which can be produced with the help of an appropriate stamp. It should be noted that when the stamp or insert is removed from the cavity 12, a similar locking effect occurs due to the elasticity of the walls 2f as in Inserting the armature 1 into the cavity 12 by inserting the bearing catches 1 a, 1 b into the bearing troughs 2a, 2b. 1 and 2 from opposing curvatures or bearing catches 1a, 1b b on the armature 1 and matching recesses or bearing troughs 2a, 2b inside the coil body 2 is loosely tolerated so that the armature 1 has at least two limited degrees of freedom. There is a limited degree of freedom in the direction of rotation about the pivot axis x and the other in the tilting direction about the axis y (FIG. 1), which extends transversely to the pivot axis x.

Both the curvatures of the bearing catches 1a and 1b and the indentations 2a and 2b are shape-bound and can therefore be manufactured precisely. The walls 2f must yield in a correspondingly resilient manner so that the die or the insert which causes the indentations 2a and 2b can be removed in the production of the coil former 2 without destruction. For this reason, the ribs 2c and 2d are not only relatively narrow but also arranged in the center where the suspension is at its greatest. In addition, with a possible pendulum movement of the armature 1, the ribs 2c and 2d arranged in the center allow the limited degree of freedom in the y-tilt direction, as a result of which tolerance compensation is achieved during contacting of the armature ends 11, 11 'with the mating contacts, not shown.

Since the relay coil 5 is wound with different mechanical tension and temperature fluctuations also occur, care must be taken to ensure that the variable pressure is not transferred to the bearing devices formed from bearing catches 1a and 1b and bearing troughs 2a and 2b. For this reason, the outer sides of the bearing-supporting walls 2f of the coil body 2 are exposed through the recesses 2g with respect to the coil winding 5.

FIG. 3 and FIG. 4 show another embodiment of a relay according to the invention, which is constructed in a centrally symmetrical manner, the reference symbols also applying to the unmarked, respectively symmetrically arranged parts. This embodiment shows a bistable polarized relay with at least one permanent magnet 6, which preferably consists of an electrically insulating ferrite that can be activated to form a getter, and on which pole shoes 3 and 3 ′ rest. On the pole pieces there are resiliently fastened counter-contacts 4 and 4 'made of erosion-resistant material, e.g. tungsten or silver-cadmium oxide, which serve as pre- and post-contacts during the switching process, as well as a noble metal main contact which, for example, consists of a galvanic silver coating on the pole pieces 3 , 3 'exists and allows an essentially voltage-free switching and guiding of the load current, which flows from one end of the armature to the other. A more detailed explanation of the effect of these contacts is described in EP-A 13 991. From this, it can also be seen that the anchor ends with flat contacts with the opposite fixed contacts at least come into line contact, which is guaranteed by the tolerance-compensating play in the A- ', ₃ rlageru ^q g. Of course, the bearing clearance must not be too great, because otherwise the response values of the relay would spread too far. The armature arranged in this way takes over the function of a bridge contact with double interruption of the load circuit.

As can also be seen from FIG. 3, the armature 1 has two armature arms 16a, 16a ', which do not appear to be assembled symmetrically, but somewhat shifted transversely to the longitudinal axis of the armature. As a result of this displacement, bearing shoulders 19a, 19b form as bearing surfaces on the bottom and top of the armature. Opposing the bearing shoulders 19a, 19b are complementarily shaped counter-bearing shoulders 20a, 20b in the ribs 2'c, 2'd. The ribs 2'c, 2'd are tapered, similar to the ribs 2c, 2d of FIG. 1, from the central region of the coil body to the ends thereof, but in the embodiment according to FIG. 3, only provided on one side in accordance with the centrally symmetrical design. 3, the web 2'd is formed on the right-hand side, so that the armature arm 16a on the left-hand side is offset by its lower surface parallel to the axis of the cavity 12 from the counter-bearing shoulder 20b to the free end 11 of the armature arm 16a extends where the contact surface 1c cooperates with the resilient mating contact 4 '. In the same way, the rib 2'c is formed on the upper wall 2'f with the counter-bearing shoulder 20a, which cooperates with the bearing shoulder 19a of the armature 1, the upper surface of the armature arm 16'a being parallel in the position shown in FIG. 3 leads to the axis of the cavity 12 to the armature end 11 ', where the contact surface 1'c cooperates with the resilient mating contact 4.

In this embodiment as well, the bearing shoulders 19a and 19b are of partially cylindrical shape, the cylinder axis coinciding with the pivot axis x. The same applies to the correspondingly shaped counter-bearing shoulders 20a and 20b, which are formed by the ribs 2'c and 2'd. The arc length of the cylinder segment is so large that the anchor, even when it is in its central position during the switching process between two contacts, cannot lift off the counter-bearing shoulders in the event of a vibration, but is securely supported there. This means that the armature 1 also engages in the counter bearing shoulders during assembly with its bearing shoulders acting as bearing catches.

In the embodiment according to FIG. 3, the armature arms 16a, 16'a each extend into a contact space 21 which is enclosed by opposing pole pieces 3, 3 'and a permanent magnet 6. In the pole pieces 3, 3 ', the resilient mating contacts 4 and 4' are next to each other

arranged so that they face a contact surface 1c, 1d of the armature. Through the contact spaces 21, the cavity 12 is closed, which can be filled with a protective gas if necessary.

Support walls 22 extend from the end faces 13, 13 ', which surround the permanent magnet 6 and the pole shoes 3, 3' and the contacts 4, 4 'as protective walls, and also support a relay housing 23 on the end face, the upper part of the housing 23 is supported by the flanges of the bobbin 2. The support walls 22 are integrally formed on the coil body 2 in the embodiment of FIG. 3.

5 to 7 show another embodiment of a relay according to the invention, each with two circuits and thus two coupled armatures 1 ', 1 ". In order to bring about a synchronous switching of the two armatures 1', 1", these are made of an insulating material existing bearing part 7 articulated, the bearing point is designed according to the preceding examples. For this purpose, pins 7a, 7b and 7c are formed on the bearing part 7 and extend into corresponding recesses 1'a, 1'b and 1'c in the two anchors 1 ', 1' '. In this embodiment, it is necessary that between the recesses 1'a, 1'c and the pins 7a, 7c there is a substantially greater play than between the recess 1'b and the actual bearing pin 7b. Essentially two such connections are sufficient, but three such connections increase the mechanical life.

As can be seen from Fig. 6, the two anchors 1 ', 1 "are designed in accordance with the outer part of the bearing part 7, so that the two anchors 1', 1" and the bearing part 7 in a composite form look like a homogeneous anchor. On the outer sides 17 'of the partial armature 1' and 18 'of the partial armature 1 ", bearing surfaces 24 are formed which, in conjunction with the inner surfaces of the coil body walls 2'e, 2'h, compress the armatures 1', 1" and the bearing part 7. Such lateral tilting bearing surfaces are particularly useful in the case of composite anchors.

In a further embodiment, these counter bearing surfaces can be designed in the form of correspondingly shaped troughs and also form a corresponding latching connection for the tilting bearings, as is provided for the pivot bearings.

According to FIG. 7, in this embodiment too, recesses 2h in the upper and lower walls 2'f of the coil former 2 are formed on the outside of the coil towards the winding, which are rectangular here in cross section, in order to increase the elasticity and to avoid pressure from the winding are trained.

In a further embodiment according to FIGS. 8 to 11, a relay is shown which can also close two circuits in each switching position. 9 and 11 show, the two partial anchors 10, 10 'laterally with a bearing element 7 consisting of two parts 7', 7 "via molded pins 7'a, 7'b, which in corresponding bores 10a, 10a The bearing part 7 'has opposite curvatures 7'c which act as bearing catches, are connected by means of a web 7'd and in the indentations in the form of bearing troughs 2a in the interior of the coil body 2 the entire armature 10, 10, store.

Due to the play between the bearing pins 7'a and 7'b and the corresponding bores 10a and 10a 'in the two armatures 10, 10', there are limited, tolerance-compensating degrees of freedom both of the two armatures with respect to one another and with respect to the respective fixed contacts 3a, 3a ', 3b, 3b '. This results in largely synchronous contact actuation in both circuits and balanced contact forces on both sides of the armature.

This type of bridge contact has the advantage over the previously described ones that the contact bridge runs perpendicular to the magnetic fluxes, so that a magnetic blow-out effect occurs on an arc occurring during the switching process.

Since there are also air and creepage distances in the case of current-carrying parts, the bearing parts 7 ', 7 "are assembled with inclined surfaces 7'e (FIG. 11) between them, so that the armature essentially consists of four parts is formed, namely the left partial anchor 10, the right partial anchor 10 'and the two bearing parts 7', 7 ", which the anchors clamped together by the pins 7'a, 7'b.

The curvatures 7'c described above as bearing catches are formed on both bearing parts 7 ', 7 ". In addition, each bearing part 7', 7" can also have bearing surfaces 24 ', as in the embodiment according to FIG. 6, so that at the same time with a tilting bearing the two anchors 10, 10 'are firmly clamped by the pressure acting on the bearing surfaces 24' from the side walls acting as a counter bearing, which pressure can be reduced to zero, depending on the design and the winding.

The parts 7 ', 7 "of the bearing element 7 can be made of a different material than the anchor itself, so that the anchor is extremely simple to manufacture and almost all functional shapes can be concentrated on the bearing element 7.

Claims (11)

1. An electromagnetic relay, the bobbin (2) of which has a cavity (12) extending along the longitudinal axis (y) of the bobbin, wherein an armature is mounted for pivotal movement about an axis (x) extending transversely to the longitudinal axis (y) by means of curved first bearing surfaces (2a, 2b) disposed opposite to each other and formed at two walls of the bobbin cavity (12),
characterised in that two second bearing surfaces (1a), which correspond to the first bearing surfaces (2a, 2b) formed on the integral bobbin (2), are formed on two opposite side surfaces of the armature (1), the second bearing surfaces together with the first bearing surfaces (2a, 2b) directly forming the armature bearing, and that the bobbin walls (2g) providing the first bearing surfaces (2a, 2b; 20a, 20b) are formed with such elasticity that the armature (1) may be inserted into the cavity (12) and have its bearing surfaces (1a, 1b) snapped-in between the bearing surfaces (2a, 2b) of the bobbin (2).

2. The relay of claim 1, characterised in that the armature (1) has third bearing surfaces (24) which, together with fourth bearing surfaces formed by opposite side surfaces (2a, 2k) of the cavity (12), support the armature (1) in the tilting direction about the longitudinal axis (y) of the bobbin (2).

3. The relay of claim 1 or 2, characterised in that the center of curvature of the first and second bearing surfaces (2a, 2b, 1 a, 1 b) lies on the pivot axis (x).

4. The relay of any of claims 1 to 3,
characterised in that the first and second bearing surfaces are formed as bearing shoulders (20a, 20b, 19a, 19b) disposed opposite to each other in such a manner that they limit any displacement of the armature (1) in either direction along the longitudinal axis (y) of the bobbin.

5. The relay of any of claims 1 to 4,
characterised in that the second bearing surfaces (1'a, 1'b; 7c, 7'c) are provided on a bearing member (7; 7'; 7") inserted into the armature (1', 1"; 10, 10').

6. The relay of claim 5, characterised in that the armature and the bearing members each consist of two parts (10, 10'; 7', 7"), each part of the bearing member having retaining means (7'a, 7'b) for receiving the corresponding armature part with a play.

7. The relay of claim 5, characterised in that the armature is formed of two parts (1', 1 ") disposed on opposite sides of the bearing member (7).

8. The relay of any of claims 1 to 7,
characterised in that the first bearing surfaces (2a, 2b; 20a, 20b) are formed by ribs (2c, 2d) extending inwardly from opposite walls (2f) of the cavity (12).

9. The relay of claim 8,characterised in that the ribs (2c, 2d) extend in the longitudinal direction of the cavity (12) in the plane defined by the pivotal movement of the armature (1).

10. The relay of claim 9, characterised in that the ribs (2c, 2d) have a height which decreases from the middle of the bobbin (2) towards the ends thereof.

11. The relay of any of claims 1 to 10,
characterised in that the bobbin (2) has recesses (2g) formed in outer surfaces of walls (2f) carrying the coil (5).

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