EP0022953A1 - Electromagnetic relay - Google Patents

Abstract

In an electromagnetic relay, an armature block (G) serving to actuate contact springs (18) has a permanent magnet between two armature webs (9), which magnetizes the armature webs (9) in opposite directions. The pole ends (8a) of a yoke guiding the excitation flow of the relay coil project between the free ends of the armature webs (9). The anchor block (G) is suspended via a laterally formed elastic arm (15) fixed in a bearing block (16) in such a way that rotation of the anchor block (G) is based on a bending of the arm (15).

Description

The invention relates to an electromagnetic relay with an armature block, which contains a pair of armature webs with an interposed permanent magnet, which magnetizes the armature webs in opposite directions, with a substantially U-shaped yoke with projecting ends, each in an air gap between the opposite ends the armature webs are arranged, which extend beyond the sections of the armature webs that are in contact with the permanent magnet, with a coil that can be connected to a control source for excitation of the relay and with a bearing device for the armature block, such that the armature block is optionally in the direction of the projecting ends of the yoke is movable.

A relay of this type has the structure shown in Fig. 17 and is e.g. described in DE-AS 24 54 967. It has an armature block h with a pair of armature webs e, d which are arranged parallel to one another, in front of and behind projecting ends c of a yoke b which carries a coil winding a. A permanent magnet f is arranged between the anchor webs e, d. The anchor block is substantially journal-supported in the center of the anchor webs e, d by means of a round axis i in a bore j.

• (1) Die runde Achse i muß exakt am Schnittpunkt der Mittellinie X-X der Ankerstege e, d und der Mittellinie Y-Y des besagten Joches b positioniert sein.

The structure of a relay in which the reciprocating _H-he or rotational movement of the armature block is effected with such a journal bearing, has the following disadvantages:

• (1) The round axis i must be exactly at the intersection of the center line XX of the anchor bars e, d and the center line YY of said yoke b.

The necessity of this constructive measure is that the anchor webs e, d are to be supported on the projecting ends of the yoke b. If the bearing axis i is crazy from the intersection of both axes, the ends deviate from the intended setting and each form an air gap at one end, while sufficient attachment is only guaranteed at the other end. This causes bruises and poor electrical contact. Overall, it requires a high degree of manufacturing accuracy to place the round bearing axis at the intersection of the two axes.

• (2) Of course, a certain bearing clearance must also be provided between the bearing axis i and the bore j, which is within the range of the manufacturing tolerances. But because of this bearing play it can happen that one of the projecting ends of the yoke is not touched by the anchor bars, while at the other end there is satisfactory contact. This in turn leads to unstable contact making. Furthermore, the dynamic conditions of this magnet system are such that the contact forces (tightening forces) at both ends of the anchor webs concentrate on one side of the round bearing axis, the resulting force being usable as a contact force. An insufficient contact force at one end leads to a reduction in the contact force below the setpoint and ultimately causes an insufficient switching capacity for the electromagnetic relay.
• (3) In connection with the foregoing, if the bearing clearance between the bearing axis and the bore is reduced too much, the frictional resistance is increased so much that it has to be subtracted from the force causing the rotation.

Furthermore, the construction of such an anchor block is generally carried out in such a way that the permanent magnet in a one-piece pressed part in the middle between parts is arranged, which serve as anchor bars e, d. After the spraying or pressing process, however, the influence of the heat causes a change in the distance between the anchor webs, which changes the path of the anchor webs relative to the yoke.

In addition, in this known relay, the actuating part for the contact spring is molded onto the armature block. This design measure is chosen for this relay because large contact forces and a high degree of self-cleaning effect are required in order to achieve high switching loads and high resistance to contact welding. For this reason, when the contact is selected, contact is made by bending the contact springs. However, with such contact actuation parts, the armature block can move without additional precautions even if one of the contacts is welded and, regardless of the defect, can also close the other contact, which can create further problems in the circuit.

In another electromagnetic relay, one of the contacts makes contact by deflecting the spring, while the other contact is forcibly lifted off. However, there is the problem that the load capacity of the contacts is unequal, which is due to the difference in the force stored in the springs from the permanent magnetic attraction. Therefore, it is difficult to ensure a sufficiently high sensitivity with such a construction.

Object of the invention. It is now to create a relay of the type mentioned, which is simple in construction and easy to manufacture, but is still free of fluctuations in the armature air gap and the air gap between the yoke and both armature webs, which allows safe contact opening and closing, so that has stable switching behavior, and which also has a relatively large in relation to the armature opening Contact opening takes place.

According to the invention this object is achieved in that the bearing device has a resilient arm which extends away from the anchor block perpendicular to its axis of rotation and is attached to its more distant end facing away from the anchor.

These measures result in an electromagnetic relay, the contacts of which do not tend to weld, which withstand high mechanical loads and which is characterized by high electrical voltage resistance.

The frame-like part, which holds a pair of anchor bars and a permanent magnet in the middle, as well as the flexible arm, which can bend perpendicular to the direction of rotation of the anchor bars, creates a unit that makes it easy to set up the relay. The flexible arm is fixed in a bearing of the relay body. This arrangement requires neither a journal nor a hole in the anchor block and therefore does not require any special precision in order to achieve sufficient accuracy for the axis of rotation.

Furthermore, an advantageous embodiment of the invention can consist in the shape of one of the anchor webs, the actuating pieces and the flexible arm, which ensures the rotatable mounting of the anchor, in order to ensure an exact anchor air gap.

According to a development of the invention, cranks are provided on the surfaces of the two actuating pieces, through which the contact springs are guided in such a way that the inside of each crank encompasses the contact spring in a gap, so that both resilient contact and forced contact opening are ensured.

Furthermore, according to a further embodiment of the invention, one of the two contacts is forced on one openable contact spring attached, which is provided with an auxiliary spring. In order to increase the contact spring force and thereby bring about symmetry in the force of the mentioned and the opposite contact spring as well as to achieve corresponding tightening forces in both switching directions, the auxiliary spring is designed such that it is supported on a fixed part immediately before lifting off.

The invention is described below with reference to the embodiments shown in the drawings.

• Fig. 1 eine Vorderansicht im Schnitt,
• Fig. 2 und 3 Längsschnitte gemäß den Linien A-A bzw. B-B in Fig. 1,
• Fig. 4 bis 6 Querschnitte gemäß den Linien C-C, D-D bzw. E-E in Fig. 1,
• Fig. 7 eine perspektivische Darstellung des zerlegten Relais,
• Fig. 8 eine perspektivische Darstellung von wichtigen Einzelteilen des Relais,
• Fig. 9 und 10 perspektivische Darstellungen verschiedener Ausführungsbeispiele,
• Fig. 11 ein Schnittbild eines anderen Ausführungsbeispiels,
• Fig. 12 eine vergrößerte Darstellung, an der die Arbeitsweise des Relais erläutert wird,
• Fig. 13 und 14 Ansichten, die den Schaltvorgang erläutern,
• Fig. 15 eine schematische Darstellung eines weiteren Ausführungsbeispiels der Erfindung,
• Fig. 16 ein Ausführungsbeispiel eines Relais mit zwangsweiser Kontaktöffnung, und
• Fig. 17 ein dem Stand der Technik zuzuordnendes Relais.

In detail shows

• 1 is a front view in section,
• 2 and 3 longitudinal sections along the lines AA and BB in Fig. 1,
• 4 to 6 cross sections along the lines CC, DD and EE in Fig. 1,
• 7 is a perspective view of the disassembled relay,
• 8 is a perspective view of important individual parts of the relay,
• 9 and 10 are perspective views of various embodiments,
• 11 is a sectional view of another embodiment,
• 12 is an enlarged view on which the operation of the relay is explained,
• 13 and 14 views explaining the switching process,
• 15 shows a schematic illustration of a further exemplary embodiment of the invention,
• Fig. 16 shows an embodiment of a relay with a forced contact opening, and
• 17 shows a relay to be assigned to the prior art.

In the relay shown in the figures, 1 denotes a housing which consists of a base plate 2 consists of insulating material or plastic and a housing cap 3. 4 with a bobbin is designated, which has a winding area 5 and two flanges 6. The winding area 5 of the bobbin 4 is provided with a continuous opening 7, in which a yoke 8 is arranged such that 6 ends 8a protrude upward at the opposite flanges. The coil winding C, the coil body 4 and the yoke 8 together form the electromagnetic circuit M.

A pair of anchor webs 9, which are opposite the projecting ends 8a on both sides, have pole faces 9a, 9b which are adapted to the projecting ends 8a of the yoke for making contact. One pole face is wider than the other. A plate-shaped or cuboid permanent magnet 10 is arranged between the anchor webs 9.

An insulating frame 11 holds the anchor bars 9 and the permanent magnet 10 together. It has on the upper side a wall 12 along which one of the anchor webs extends, a pair of posts 13 through which one anchor web is passed, and a horizontal wall 14 which, together with the post 13, has a cavity for receiving the permanent magnet 10 forms. A projection 14a on the horizontal wall 14 serves to position the permanent magnet, receives the other armature web and encloses it with the exception of the pole faces 9a, 9b. All walls are integrally connected to the insulating frame 11. One anchor web 9, which penetrates the posts 13, is designed as a thin plate in order to facilitate insertion into the mold and, at the same time, embedding.

The insulating frame 11 also has a resilient arm 15 projecting in the middle, which can bend in the direction T perpendicular to the direction of rotation R of the anchor webs 9 (FIG. 12). In Figures 1, 6, 7 and 10, the insulating frame 11 including the flexible arm 15 is made of a plastic high arc resistance shaped. In the embodiment shown in FIG. 11, the arm 15 is formed from a metallic leaf spring embedded in the insulating frame 11. For this reason, the term "structural unit" is used because, in contrast to the known rotating anchor system with a journal bearing, it works as a whole without play. The arm 15 can also be provided on both sides as shown in FIGS. 10 and 11. Relatively stiff synthetic resin can also be used as long as sufficient flexibility can be ensured by the thickness or shape of the arm 15. The two anchor bars 9, the permanent magnet 10, the insulating frame 11 and the resilient arm 15 together form the anchor block G.

The base plate 2 is provided with a bearing block 16. In order to increase the flexibility, the arm 15 is tapered in cross-section in the area of its connection 15b near the insulating frame 11 and widened at its front end 15a in such a way that an air gap 16a arises in the area of the connection 15b and that its front, widened end 15a against a pair of firmly anchored side walls 17.

With 18 movable contact springs are designated, which are arranged on both sides of the flexible arm 15. Each of these springs lies opposite the upper wall 12 of the insulating frame 11 of the anchor block and is provided with a contact 19 at its front end. Each contact spring 18 is also fastened to an L-shaped base part 20a of a contact connection 20 with an L-shaped foot part 18a. The movable contact spring 18 engages the inner surface 22 of a bend of an operating part 21 for the purpose of a forced contact opening. With 23 a further contact connection is designated, which carries a fixed contact 24. The two contacts 19 and 24 form a contact arrangement S.

The base plate 2 has an upright partition 25, which is arranged as an arc protection between this contact arrangement S on the one hand and the part M of the electromagnetic circuit and the armature block G on the other. The partition 25 is integrally formed on the side walls 17 of the bearing block 16. A connecting pin 26 for the excitation coil C is L-shaped, its horizontal section 26a being passed through the flange 6 of the coil body 4. The contact and coil connections 20, 23 and 26 penetrate the base plate 2.

Fig. 15 is a schematic representation of a further preferred embodiment of the invention, which ensures a better coordination of spring force and actuating force. The one of two contacts, which is denoted by 27, is closed by bending the contact spring and stands out from the fixed contact 28 serving as an abutment when there is no force from the armature 30. The other contact with the contact spring 29 is forcibly opened and then closed when no force is exerted by the armature. The spring 29 of the contact which is forcibly opened carries the movable contact 31 on the side facing the armature 30 and, on the other side, an auxiliary spring 32 which is supported on it and which is also fastened to the same contact connection 33. The free end of the auxiliary spring 32 is not always supported on the contact spring 29 but only when the contact spring 29 is lifted off the fixed contact 28. The spring force of the contact spring 29 is increased by the force of the auxiliary spring 32 at this time. The resulting spring force from the deflection when contact is made, the forced contact opening and the auxiliary spring at the end of the armature movement on the side on which the contact is opened takes on an increased value until the spring force on the side at the contact opening takes place the same is the value of the spring force on the side where the contact is closed. In this way, the resulting spring force becomes the actuating force of the armature adjusted.

The operation of the relay according to the invention is described below. Fig. 13 (Fig. 13a shows the rest position of the relay) shows an arrangement with a working and a normally closed contact, in which the armature block G is moved when the coil is excited over the flexible arm 15, whereby the contact arrangements S on both sides be opened and closed alternately, as indicated in (a) and (b).

In FIG. 14, which shows another arrangement with two working contacts (FIG. 14a shows the rest position of the relay), the rotation of the armature block G causes the two contact arrangements on both sides to open or close simultaneously. The arrangement of FIG. 13 corresponds to the construction shown in FIG. 7 and the arrangement according to FIG. 14 corresponds to that shown in FIG. 9.

The relationship between the anchor block G and the elastic arm 15 is that the arm 15 is bent in a direction T perpendicular to the axis of rotation of the anchor block G in response to its rotation, as shown in FIG. If the axis of rotation is displaced from the normal position, a subsequent movement to the right or left or forwards or backwards occurs within the range of the deflection to compensate for the offset, thereby compensating for the problem of chattering or excessive play on the axis of rotation.

Since the electromagnetic relay according to the invention is designed such that the insulating frame 11, which carries the armature webs 9 and the permanent magnet 10, is integrally formed with the elastic arm 15, which can bend perpendicular to the direction of the axis of rotation of the armature webs 9 and from the bearing block 16 of the base plate 2 is held securely, any offset due to a deflection of the elastic arm 15 by the said subsequent movement is rendered ineffective. This arrangement makes it unnecessary to take great care in centering to dedicate, which was necessary with conventional journal bearings. Since the armature block G is also a unit which comprises the armature webs 9, the permanent magnet 10 and an insulating frame 11, the final assembly compared to the known relays according to the prior art, in which only one part at a time can be installed in the housing , made much more efficient.

In addition to the features described above, the electromagnetic relay according to the invention is further characterized in that the upright partition 25 is provided in its base plate 2 in order to provide protection against arcing between the contacts. Furthermore, the common contact spring 18 is designed so that it comes into engagement with the inner surface of the offset of the actuating part 21. The insulating frame 11, which carries the anchor bars 9 and the permanent magnet 10, is on its top with the wall 12, along which one of the anchor bars is arranged, the pair of posts 13, which an anchor bar passes, and the horizontal wall 14, which together with said posts 13 forms a cavity for receiving and fastening the permanent magnet. Added to this is the wall projection 14a, which extends from the horizontal wall and together with this forms a positioning segment for the permanent magnet, which is adapted to and covers the other armature web 9, the pole faces 9a and 9b of which alone remain uncovered. All the walls mentioned are integrally connected to the frame part.

In addition, one of the contact springs is provided with a contact that springs through when contact is made, while the other contact spring carries a contact that is forced to open. The first-mentioned contact spring is provided with an auxiliary spring which is supported on the surface of the contact spring facing away from the moving contact, as a result of which the advantages mentioned are achieved.

16 also shows a rotary anchor in which an anchor provided with permanent magnets is attached to one flexible arm or web 15 is mounted on one side in a bearing block 16. The flexible web 15, like the actuating pieces 21a, 21b, 21a ', 21b', is molded from the insulating material jacket or the insulating material frame 11 of the armature. The insulating material jacket also fixes in the armature at least one permanent magnet (not shown) and armature webs 9, which interact with the yoke ends 8a of the coil core. The actuating pieces 21a, 21b and 21a ', 21b' shown in section are connected to one another on their upper side, that is to say they grip around the contact springs 18 and 18 '.

In the illustration, the right contact 19, 24 is closed, the left contact 19 ', 24' is open. To make contact, the spherical actuating piece 21b presses against the contact spring 18, while the opposite actuating piece 21a is lifted off the latter. According to the relatively long spring travel L ₂ , the contact spring 18 experiences considerable deflection. In contrast, the contact opening at the left contact point 19 ', 24' takes place through the action of the actuating piece 21a 'on the contact spring 18', the actuating piece 21b 'being lifted off the contact spring. At the beginning of the opening process, the contact-near section 21c, 21c 'of the actuating piece 21a, 21a' engages with the contact spring 18 ', so that only the short resilient length L ₃ , L ₃ ' is effective up to the contact point. The point of contact on the contact spring moves with increasing opening of the contact 19 ', 24', since the surface of the actuating piece 21a 'facing the contact spring 18' runs parallel to the longitudinal axis of the armature 8, from the portion near the contact to the non-contact portion 21d 'of the actuating piece 21a' .

In this exemplary embodiment of the invention it is thus ensured that the contact is made over long spring travel L ₂ , L ₂ ', but the opening takes place over short and thus stiff sections L ₃ , L ₃ '. In addition In addition to the advantages described in connection with the above-described exemplary embodiments of the invention, an enlargement of the contact opening is achieved in the present case by moving the point of application of the actuating element 21a 'from the portion 21c' closer to the contact to the portion 21d 'which is further away from the contact.

As a result of the strong deflection when contact is made, the permanent magnetic attraction force can also be stored well in the contact springs 18, 18 '. Due to the slight deflection of the contact springs 18, 18 'at the contact opening, however, in the case of contact welding, the welded contact is either torn open and the other is actuated properly - or, if the weld cannot be broken, the other contact is also no longer actuated.

Claims (7)

1. Electromagnetic relay with an armature block (G), which contains a pair of armature webs (9) with an interposed permanent magnet (10), which magnetizes the armature webs (9) in opposite directions, with an essentially U-shaped yoke (8) projecting ends (8a), which are each arranged in an air gap between the opposite ends of the armature webs (9), which extend beyond the sections of the armature webs (9) which are in contact with the permanent magnet (10), with one to one Control source switchable coil (C) for energizing the relay and with a bearing device (15, 16) for the armature block (G) such that the armature block (G) is optionally movable in the direction of the projecting ends (8a) of the yoke (8) characterized in that the bearing device has a resilient arm (15) which extends away from the anchor block (G) perpendicular to its axis of rotation and fastens to its remote side (15a) remote from the anchor is. 2. Electromagnetic relay according to claim 1, characterized in that one of the anchor webs (9) is embedded in a base plate (14) made of plastic, that the base plate (14) further integrally molded actuating pieces (21) for actuating a pair of contact springs ( 18), the resilient arm (15) and one for the on Assumption of the permanent magnet (10) has adapted cavity, and that the other armature web (9) is positioned and fixed by support on the permanent magnet (10) in the cavity. 3. Electromagnetic relay according to claim 2, characterized in that each of the actuating pieces (21) has a pressure surface for actuating the contact spring (18) and an offset, which is designed so that it forcibly opens the respective contact (19, 24), by engaging the surface of the contact spring (18) which is on the opposite side of the pressure surface. 4. Electromagnetic relay according to claim 1, characterized in that two contacts (28, 31) are embedded in a plastic base plate (2) and are accommodated independently of one another in two compartments, and that the compartments through the base plate (2) and a fixed section on front end of the elastic arm (15) are formed. 5. Electromagnetic relay according to claim 4, characterized in that one of the contacts (28, 31) has a force-opening contact spring (29) and is provided with an auxiliary spring (32) which is designed such that it is immediately before Contact opening against a stationary part to increase the spring force of the contact spring (29). 6. Electromagnetic relay according to claim 1 to 4, characterized in that the armature block (G) for actuating each contact spring (18) each has a contact spring (18) encompassing actuating piece (21) that the actuating pieces (21) each have pressure surfaces (21b) on one side, facing away from the contact to be closed, of the contact spring (18) for making contact and in each case offsets (21a) on the other side, facing the opening contact, of the contact spring (18) for forced contact opening, and that the pressure surfaces (21b) on the contact springs (18) are further away from the contact point than the contact points (21c) of the bent portions (21a) which are decisive for the contact opening. 7. Electromagnetic relay according to claim 6, characterized in that the bends effective for the contact opening (21a) have a closer and non-contact portion (21c, 21d), that the contact opening is initiated by the action of the closer contact portion (21c), and that in the course of the opening process, the point of contact on the contact spring (18) moves from the section (21c) closer to the contact to the section (21d) of the offset (21a) which is further away from the contact.

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