EP2831900B1 - Polarized electromagnetic relay and method for production thereof - Google Patents

Description

Field of the invention

The invention relates to a method for producing a polarized electromagnetic relay with an electromagnet, permanent magnet, armature and actuatable switch and to a polarized electromagnetic relay produced in this way.

Background of the invention

Poled, electromagnetic relays are available with a three-pole permanent magnet ( WO 93/23866 ) and with two-pole permanent magnet ( U.S. 4,912,438 , U.S. 5,153,543 , US 6,670,871 B1 ). In any case, the electromagnet has a coil with a core and pole pieces in a yoke-shaped structure. In the case of a three-pole permanent magnet, this permanent magnet is arranged between the two yoke legs above the coil and parallel to the coil axis. This permanent magnet can be separated from a magnetized band and inserted into the coil body between the two yoke legs. In the case of a two-pole permanent magnet, this is magnetically connected at right angles to the coil axis with a pole in about the middle of the old core ( U.S. 4,912,438 , U.S. 5,153,543 ).

Out U.S. 4,975,666 a polarized, electromagnetic relay is known which has a base housing open at the top, in which an electromagnetic block with coil, core and pole legs and, between the pole legs, a permanent magnet, and on the pole legs, a valve block with armature and switch elements are mounted. The design does not allow the permanent magnet located between the pole legs to be generated from an unmagnetized ferromagnetic precursor by magnetization, because the coil would be damaged by excessive, induced currents.

Out DE 195 20 220 C1 Another polarized electromagnetic relay is known in which the coil, together with two ferromagnetic yokes and a permanent magnet inserted between them, are joined from above in a base body and fixed with potting compound. Magnetization from a non-magnetized precursor in the installed state is not possible.

A relay with a two-pole permanent magnet is also known ( US 6,670 871 B1 ), which extends parallel to the coil axis. The plate-shaped permanent magnet with poles on the top and bottom is held in an anchor plate. The electromagnet is housed in a two-part housing which has a trough-shaped lower part and a box-shaped upper part on which the fixed contacts of the switches and the rotating supports for the armature are located. The movable contact springs are embedded in the insulating anchor plate. A recess in the anchor plate is used to accommodate the two-pole permanent magnet. Whether the permanent magnet is embedded in the armature plate is magnetized is not disclosed in the document. In any case, this is a disadvantage large distance of the two-pole permanent magnet from the core of the electromagnet, which results in a large, ferromagnet-free path in the closed magnetic flux path, which results in a large magnetic resistance in every position of the armature.

The DE 38 02 688 A1 shows a polarized relay with an insulating base body in the form of a flat trough which has a central, elongated recess for receiving the coil of the polarized relay. The coil forms a structural unit with the core and pole pieces, which is built into the recess of the tub in order to work together with counter-contact elements, connection elements for armature contact springs and with coil connection elements. As a result of these elements, there is no lateral accessibility to the recess, which is therefore not designed in the manner of a drawer.

Out DE 197 19 355 C1 a polarized electromagnetic relay is known which comprises a base body with a partition which isolates an overhead coil from a base arranged below. The coil with core and pole pieces as well as with winding connection elements is installed from above into the cavity of the base body, the winding connection elements reaching through recesses in the partition wall and being connected to the base of the device, which is housed in the space below the partition wall. A drawer-like receiving space, which would have to be accessible from the side of the base body, is not provided.

In order to be able to implement small polarized relays, very strong permanent magnets are required. Such strong permanent magnets are available with a proportion of rare earths. Because of the strong attractive forces between the magnets, however, handling them from a supply of individual magnets is difficult, not only in terms of the adhesion of the magnets to one another, but also in terms of keeping chips and dust particles free from the pole faces during installation. From a technological point of view of manufacture, it is more advantageous to use a piece of material made from a non-magnetized ferromagnetic alloy and to “magnetize” the "precursor" after it has been installed in the relay. Magnetization in place with high field strengths, however, harbors the risk that other components of the magnetic system of the relay will be damaged, in particular the coil of the electromagnet due to strong, induced voltages and currents.

Brief description of the invention

The invention is based on the object of magnetizing the permanent magnet of a polarized relay without endangering other relay parts.

According to the invention, the components of the relay are designed separately in connection with special manufacturing steps, so that the permanent magnet can be magnetized without the risk of damaging the coil of the electromagnet.

In detail, a coil assembly with coil, core and pole pieces is provided as a component of the relay, and also a carrier component in which magnetic flux parts of the magnetic system of the relay are included, including the pole pieces of the electromagnet and a bearing piece of the armature. These magnetic flux parts are made of soft iron and are not damaged by high magnetic field strengths. In the course of the magnetic flux parts, a one-piece or two-piece permanent magnet precursor made of non-magnetized, ferromagnetic alloy is built into the carrier component, which results in the permanent magnet by magnetization. The carrier component also has a receiving space into which the separately produced coil assembly, which represents the sensitive part of the electromagnet, is inserted and mounted after the permanent magnet has been magnetized. Then the remaining relay components to complete the relay are installed, including the switches operated by the relay.

The invention also relates to a polarized electromagnetic relay which comprises an electromagnet, a pole assembly with magnetic flux parts and with a permanent magnet, a carrier component and an armature. The electromagnet comprises a coil assembly, which is designed as a unit with coil, core and pole pieces. The support component is preferably tiered and comprises an upper-side cavity as a receiving space for the pole assembly with the magnetic flux parts and the magnetized permanent magnet as well as a central slot as a receiving space for the coil assembly. The armature of the relay is arranged pivotably relative to the electromagnet on the carrier component and is connected to the movable switch elements.

With this design, small and narrow, polarized relays with high sensitivity can also be produced. Various functions of polarized relays can be implemented by modifying component parameters.

Further details of the invention emerge from the following description of two exemplary embodiments with reference to the drawings and the claims.

Brief description of the drawings

Fig. 1

eine perspektivische Ansicht einer ersten Ausführungsform eines Relais schräg von oben auf eine Längsseite und eine Schmalseite bei abgezogener Gehäusehaube,

Fig. 2

einen Längsschnitt durch das Relais der ersten Ausführungsform,

Fig. 3

eine perspektivische Ansicht eines Trägerbauteils schräg von oben und auf eine Längsseite sowie eine Stirnseite,

Fig. 4

eine perspektivische Ansicht einer Spulenbaugruppe,

Fig. 5

eine Explosionsdarstellung der Einzelteile des Relais der ersten Ausführungsform,

Fig. 6

eine zweite Ausführungsform des Relais in perspektivischer Ansicht,

Fig. 7

einen Längsschnitt durch das Relais der Fig. 6, und

Fig. 8

eine Explosionsdarstellung der Einzelteile des Relais der Fig. 6.

Show it:

Fig. 1

a perspective view of a first embodiment of a relay obliquely from above on a long side and a narrow side with the housing cover removed,

Fig. 2

a longitudinal section through the relay of the first embodiment,

Fig. 3

a perspective view of a carrier component obliquely from above and on a longitudinal side and an end face,

Fig. 4

a perspective view of a coil assembly,

Fig. 5

an exploded view of the individual parts of the relay of the first embodiment,

Fig. 6

a second embodiment of the relay in perspective view,

Fig. 7

a longitudinal section through the relay of the Fig. 6 , and

Fig. 8

an exploded view of the individual parts of the relay Fig. 6 .

Detailed description of the invention

The electromagnetic relay is made up of a magnet system and a switch system, which are held together and protected by housing components. The magnet system comprises an electromagnet, which consists of a coil assembly 10 ( Fig. 4 ) and pole pieces ( Fig. 2 ) consists. The coil assembly 10 comprises a coil 1 wound on a coil body 5, a ferromagnetic core 2 and ferromagnetic pole pieces 3 and 4, which form a structural unit. The core 2 is integrally connected to one of the two pole pieces 3, 4 or to both pole pieces. Still belong to the magnet system Magnetic flux parts 7, 8, 9, a permanent magnet 11 and an armature 12. The magnetic flux parts 7 and 8 form the pole pieces of the electromagnet. The magnetic flux part 9 forms a bearing piece for the armature 12, which is designed here as a rocking armature. The permanent magnet 11 of the first embodiment has two poles and is arranged between the pole piece 7 and the magnetic flux part 9, while there is a magnetic flux interruption between the parts 8 and 9. It is also possible to swap the arrangement of the permanent magnet and the magnetic flux gap. The alignment of the poles of the permanent magnet with respect to the pole piece 7 or 8 and the magnetic flux part 9 is important. The magnetic flux parts 7, 8, 9 and the permanent magnet 11 form a pole assembly.

In the illustrated embodiment ( Fig. 4 ) a connection block 6 is connected to the coil assembly 10, which is not necessary in the context of the invention. The connection block 6 comprises switching signal connection pins 15, 16 with bending legs 15a, 16a for direct connection to the winding ends of the coil 1. A test contact connection pin 25 is cranked and can thus be clamped between connection block 6 and pole piece 3.

This in Fig. 4 The component shown is designed to be placed in a drawer-like receiving space 42 of a storey-like support component 40 ( Fig. 3 ) to be pushed in and assembled. For this purpose, the drawer 42 has two cavity expansions 43 and 44 in order to receive and position the connection block 6 in addition to the coil assembly 10.

The tiered support component 40 is also responsible for receiving the pole assembly, that is to say the magnetic flux parts 7, 8, 9 and the permanent magnet 11. For this purpose, an anchor-side receiving space 41 divided into niches is provided. The parts 7, 8, 9 and 11 are fastened in the carrier component 40 by embedding. Various embedding methods come into consideration, for example overmolding, gluing, pressing in. On the upper side of the carrier component 40, a fixed contact 21 is also provided, which is in electrical connection with a connection pin 26, which is also fastened in the carrier component 40 by embedding.

The switch system contains a diagnostic switch 20 and at least one load switch 30. The diagnostic switch 20 comprises the fixed contact 21 and a movable contact 22 which is attached as a double contact to the fork-shaped end of a contact spring 23. The contact spring 23 is attached to the leg 12a of the armature 12 and is actuated by the latter. The movable contact 22 establishes the electrical connection with the connecting pin 25.

In a modified embodiment of the invention, the test contact connection pin 25 is embedded in the support component 40 parallel to the test contact connection pin 26 (not shown) and two separate fixed contacts are provided on the top of the support component 40. In this embodiment, the end of the contact spring 23 is used as a bridge contact for closing the switch 20.

The load switch 30 comprises a fixed contact 31 and a movable contact 32 which is seated on a contact spring 33 which is fastened to the carrier component 40 via a busbar 34 and is also in electrical connection with a load connection pin 35. The fixed contact 31 is in conductive connection with a further load connection pin 36. The contact spring 33 is actuated via an electrically insulating coupling member 37, the upper end of which is mechanically connected to the second leg 12b of the armature 12. The mechanical connection can take place via an overtravel spring 38, as shown, or by direct connection of the ends of the rocker armature 12 and the coupling member 37.

In addition to its two legs 12a and 12b, the armature 12 also has a curved bearing part 12c with which the armature rests on the magnetic flux part 9, which is built as a bearing piece. Depending on the type of function of the relay (monostable, bistable), the legs 12a, 12b of the armature 12 are of different lengths and are held by spring forces with different pole gap widths. Such spring forces are generated by the contact spring 23, the overtravel spring 38 (if present) and the contact spring 33. The contact spring 23 is riveted to the arm 12a of the armature and has spring extensions 23a and 23b as well as a fastening tab 23c which is welded to the bearing piece 9 in a certain angular position between armature 12 and pole surface 7. The overtravel spring 38 is similarly riveted firmly to the leg 12b and also has spring extensions 38a, 38b and a fastening tab 38c which is welded to the bearing piece 9. In addition to the force of the contact spring 33, it is primarily the torsional forces of the spring legs 23b and 38b, which are responsible for the overall spring behavior of the relay.

In addition to the spring forces, the magnetic force of attraction on the armature 12 also plays a role, whether a monostable or a bistable relay is obtained. The strength of the permanent magnet 11 and the sizes of the pole faces of the pole pieces 7, 8 play a role in the forces of attraction on the legs 12a, 12b of the armature. If the magnetic attraction force in one end position of the armature is greater than the spring force effective in the lifting direction and in the other end position the magnetic attraction force is smaller than the lifting force of the springs, then there is a monostable relay. If, on the other hand, the magnetic attraction force in both end positions of the armature is greater than the spring force effective in the lifting direction, a bistable relay is present.

While the carrier component 40 represents the main element of the housing, there is also a housing base 50 and a housing cover 60. As in FIG Fig. 1 As shown, the carrier component 40 has a guide 46 on its front side visible there for guiding the insulating coupling member 37. This guide and the top of the relay is through the housing cover 60 according to Fig. 1 mounted relay covered. A flat cavity 45 extends along the underside of the support component 40 ( Fig. 2 ), which serves to accommodate the load contact spring 33 and its freedom of movement and which is delimited from the housing base 50 at the bottom. The load contact connecting pin 36 is inserted into the base part 50 and riveted to the base part by means of the fixed contact 31.

A switch can be located on the top of the housing cover 60 in order to change the position of the armature 12 by hand.

With the Fig. 6 , 7th and 8th a second embodiment of the invention is shown. Similar components to the first embodiment are given the same reference numerals. The basic structure of the relay according to the second embodiment follows the first embodiment, which is why corresponding parts of the description are not repeated and only the differences are discussed.

In the second embodiment of the relay, the permanent magnet 11 is made from two parts 11a and 11b and with a magnetic flux part 9 made of soft iron and forms a three-pole permanent magnet. The section 11a has the stronger coercive force compared to the section 11b. The two parts 11a and 11b have the same polarity towards the magnetic flux part 9, so either both are formed there as a south pole or as a north pole, while the three-pole permanent magnet 11 then shows north poles or south poles towards the outer ends of the relay. The magnetic flux part 9 conveys the adjacent polarity, for example the south pole when the permanent magnet faces the north pole and the north pole when the permanent magnet faces the south pole.

In the second embodiment, the mounting of the armature 12 compared to the first embodiment is modified by a cross spring 39, the mounting of the armature 12 on the Magnet flux part 9 takes over. The cross spring 39 has tabs 39a, with which it is connected to the magnetic flux part 9 by welding, also a torsion bar 39b and transversely thereto a support tab 39c for supporting the armature 12. Another tab 39d can be attached to the cross spring 39, which serves to dampen the impact of the armature 12 on the magnetic flux part 8 and is tensioned at the same time, which is useful when the armature 12 is switched over later, since the armature then detaches more easily from the magnetic flux part 8. The cross spring 39 acts as a torsion spring, ie there is no bearing friction and the hysteresis losses of the spring 39 are very small.

As a further variant, the second embodiment has a one-piece design of contact spring 23 and overtravel spring 38. The contact spring 23 is electrically conductive and connected to the electrically conductive armature 12, which in turn is connected via the electrically conductive cross spring 39 to the electrically conductive magnetic flux part 9, which in turn is in electrically conductive connection to the test contact connection pin 25.

An intermediate piece 8a made of sheet metal or plastic is also provided in order to adapt the adhesive force of the armature 12 at the leg 12b to the magnetic flux part 8. Because of the different lengths of the legs 12a, 12b of the armature 12, the lifting forces exerted there are different, which is somewhat compensated for by the intermediate position of the part 8a.

The polarized electromagnetic relay is manufactured and assembled in a new way. In the Fig. 5 and Fig. 8 The individual parts shown are partially assembled into assemblies, including those in Fig. 4 The illustrated coil assembly 10. This coil assembly comprises at least the coil 1, the core 2 and the pole shoes 3 and 4. In the illustrated embodiment, there is also a coil body 5, to which a connection block 6 is flanged, via which the connections of the coil ends to the connection pins 15 , 16 run.

The ones in the Fig. 5 and 8th The individual parts shown also include a carrier component 40, which according to the invention is functionally adapted to the manufacturing method of the relay. The carrier component 40 namely contains an armature-side receiving space 41 for the magnetic flux parts 7, 8, 9 and the permanent magnet 11 as well as a drawer-like receiving space 42 for the coil assembly 10. The magnetic flux parts 7, 8 and 9 and the permanent magnet 11 can be referred to as a pole assembly, since they present the armature 12 with two outer poles and a center pole. The pole assembly is mounted in the receiving space 41 of the carrier component 40 and fastened, for example, by casting around it.

It is a special feature of the invention that when assembling the pole assembly, not a finished permanent magnet is assembled, but a permanent magnet precursor made of non-magnetized, ferromagnetic alloy with a proportion of rare earths. Such precursor magnets can be "magnetized" with extremely high coercive forces. For this purpose, a very strong magnetic field must be applied, which magnetizes the precursor magnet in the desired direction. Practically you have to put a coil around the pole assembly to generate the required field strength. This can be done in the installed state of the pole assembly in the receiving space 41 of the carrier component 40. It should be noted that the receiving space 42 for the coil assembly 10 can remain empty. This prevents a high voltage with a strong electrical current from developing in the coil assembly, which could lead to its damage.

When magnetizing the pole assembly, the type of permanent magnet to be generated must be taken into account. If a one-piece two-pole permanent magnet is to be produced, which corresponds to the first embodiment of the relay, the procedure described is sufficient. If, on the other hand, a three-pole permanent magnet is to be generated by magnetization, the procedure is modified. Two precursor magnet sections 11a, 11b are used on both sides of the central magnetic flux part 9 and in contact with the adjacent magnetic flux parts 7 and 8. One of these precursor magnet sections, here section 11a, consists of a more magnetizable alloy opposite the other section 11b. The more strongly magnetizable section 11a can also be made smaller than the less magnetizable section 11b. After assembly of the pole assembly approximately in the order of parts 7, 11a, 9, 11b and 8 in the receiving space 41 of the carrier component 40, magnetization is carried out in a certain direction, as it corresponds to the stronger partial permanent magnet 11a. Then a direction opposite to the original magnetic direction, but weaker Magnetic field applied to the pole assembly, this weaker magnetic field not being sufficient to re-magnetize the permanent magnet 11a, but sufficient to re-magnetize the weaker permanent magnet 11b. This has the consequence that poles of the same name are opposite one another on the central magnetic flux part 9. In this way, an overall permanent magnet 11 is obtained with two poles of the same name on the outside, ie to the magnetic flux parts 7 and 8 acting as pole pieces, and an opposite pole on the central magnetic flux part 9. This structure forms a three-pole permanent magnet.

After the permanent magnet 11 has been produced, the coil assembly 10 can be safely mounted in the drawer-like receiving space 42.

The other items to complete the relay are now assembled. These include the armature 12 with its springs 23, 38 and 39, the load switch 30 together with the coupling member 37 and the housing parts 50 and 60.

With the new relay, many functionalities of a polarized relay can be implemented by modifying the size, the arrangement and the parameters of individual components. Strong permanent magnets can be used without complications in the assembly of the relay, in that the permanent magnet is obtained by magnetization in the carrier component, since this does not contain any endangered components, such as the magnet coil, at the time of magnetization.

The relays can be made very small, since permanent magnets with a large coercive force can be generated.

Claims (12)

1. A method for producing a polarized electromagnetic relay comprising an electromagnet, a permanent magnet (11), an armature (12), and an actuable switch (20, 30), comprising the steps of:

   a) providing a coil assembly (10) comprising a coil (1) with a core (2) and pole pieces (3, 4) as a structural unit;

   b) providing a support component (40) that has a first accommodation space (41) for a pole assembly (7, 8, 9, 11) extending to the side of the armature, and a second accommodation space (42) for the coil assembly (10), the second accommodation space being arranged in the manner of a shelf compartment;

   c) mounting the pole assembly (7, 8, 9, 11) including magnetic flux pieces (7, 8, 9) and an unmagnetized permanent magnet precursor in the first accommodation space (41);

   d) magnetizing the permanent magnet precursor in the pole assembly while the second accommodation space (42) is empty, to obtain the permanent magnet (11);

   e) mounting the coil assembly (10) in the second accommodation space (42);

   f) mounting the rest of the relay components to complete the relay.
2. The method as claimed in claim 1, for providing a three-pole permanent magnet (11);
   wherein step c) comprises mounting two precursor magnet portions (11a, 11b) which are magnetizable to a different extent, between three magnetic flux pieces (7, 8, 9) of the pole assembly (7, 8, 9, 11); and wherein step d) comprises the sub-steps of:

   d1) magnetizing the two precursor magnet portions (11a, 11b);

   d2) remagnetizing the weaker precursor magnet portion (11b) in such a manner that like poles of the magnetized portions (11a, 11b) face each other at the magnetic flux piece (9) separating them.
3. A polarized electromagnetic relay, produced according to any one of claims 1 or 2, comprising:

   - a support component (40) of a shelf-like or storey-like configuration, having a first accommodation space (41) extending to the side of the armature, a second accommodation space (42) arranged in the manner of a shelf compartment, and a third accommodation space (45) extending to the side of a load contact, the first, second and third accommodation spaces being arranged one upon the other;

   - a pole assembly (7, 8, 9, 11) comprising magnetic flux pieces (7, 8, 9) defining a central magnetic flux piece (9) and pole pieces (7, 8) on either side thereof, and a permanent magnet (11) between at least one of the pole pieces and the central magnetic flux piece (9), the pole assembly (7, 8, 9, 11) being accommodated in the first accommodation space (41) of the support component (40);

   - a coil assembly (10) comprising a coil (1) with a core (2) and pole pieces (3, 4) as a structural unit and forming part of an electromagnet, which is accommodated in the second accommodation space (42);

   - an armature (12) which is arranged on the pole assembly (7, 8, 9, 11) and is pivotable relative thereto, and which is connected to movable switch elements (23, 33).
4. The relay as claimed in claim 3, wherein the third accommodation space (45) of the support component (40) accommodates a load switch (30) and is closed by a housing bottom (50).
5. The relay as claimed in claim 4, wherein the housing bottom (50) supports at least one fixed contact (31) of the load switch (30), and together with the support component (40) supports terminal pins (15, 16, 25, 26, 35, 36).
6. The relay as claimed in any one of claims 3 to 5,

   - wherein the electromagnet comprises a U-shaped yoke (2, 3, 4) with adjacent magnetic flux pieces (7, 8) that define pole pieces;

   - wherein the armature (12) is configured as a rocking armature having a first and a second leg (12a, 12b), the armature being supported on a central magnetic flux piece (9) and forming a closed low magnetic gap magnetic flux path, by a respective one of its legs (12a, 12b) together with the central magnetic flux piece (9) and a respective one of the magnetic flux pieces (7, 8) operative as pole pieces; and

   - wherein each of the legs (12a, 12b) actuates a movable contact (22, 32) of a respective switch (20, 30) .
7. The relay as claimed in claim 6, wherein a first switch which is usable as a diagnostic switch (20) is formed by a fixed contact (21) on the support component (40) and a movable contact (22) at a first contact spring (23) which is fixed on the first leg (12a) of the rocking armature (12), and wherein a second switch which is usable as a load switch (30) is formed by a fixed contact (31) on the housing bottom (50) and a movable contact (32) at a second contact spring (33) which is mechanically coupled to the second leg (12b) of the rocking armature (12) through an electrically insulating coupling member (37).
8. The relay as claimed in claim 7, wherein the support component (40) has a guideway (46) for the insulating coupling member (37), and wherein a housing cap (60) encloses the support component (40) thereby partially encompassing the housing bottom (50).
9. The relay as claimed in any one of claims 3 to 8, wherein the permanent magnet (11) is a one-piece component, one pole thereof adjoining the central magnetic flux piece (9) and the other pole thereof adjoining one of the magnetic flux pieces (7, 8) that are effective as magnetic poles.
10. The relay as claimed in any one of claims 3 to 8, wherein the permanent magnet (11) comprises two portions (11a, 11b) which are facing each other with like poles at the central magnetic flux piece (9) so as to form an three-pole permanent magnet (11) as a whole.
11. The relay as claimed in claim 10, wherein one of the portions (11a) has a higher coercive force than the other portion (11b).
12. The relay as claimed in claim 11, wherein the portion (11a) with the higher coercive force occupies a smaller volume than the portion (11b) with the lower coercive force.

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