EP0989575B1 - Electromagnetic relay - Google Patents

Abstract

An electromagnetic relay has a contact arrangement and a magnet system that includes a yoke (20) and an armature (30) movably mounted on the yoke, and further includes a leaf-spring (10,50) which lies flat and is fixed with a fixture section (12,14) on a smooth seating or mounting section (23,33) of a rigid carrier formed by the yoke (20) and/or the armature (30). The spring section (13,15,51) has a given amount of play (s1,s2,s3) perpendicularly to the plane of the fixture section. Between the seating or mounting section (23,33,43) and a free end (24,32,41) of the carrier is formed a roll-off zone, wedge-shaped in the idle state, for the leaf-spring (10) and which is formed by a convex curvature of a roll-off section (25,35,55) of the carrier (22,30) and/or of the leaf-spring (50) away from the plane of the seating or mounting section (23,33,43).

Description

The invention relates to an electromagnetic relay having a contact arrangement and a magnet system having a yoke and an armature movably mounted on the yoke, further comprising a leaf spring, which with a fixing portion on a flat support portion of a formed by the yoke and / or the armature, rigid support is mounted flat resting and extends with a subsequent unsecured spring portion over a free end of the carrier away, said spring portion has a predetermined range of motion perpendicular to the plane of the mounting portion.

Such relays are known and often in use. For example, a relay constructed in this way is shown in simplified form in EP 0 278 495 B1. This has a leaf spring, which is connected to both the yoke and the armature and serves both as an anchor bearing spring and forms a projecting beyond the free armature end contact spring. In the known relay forms the yoke, on which the armature is mounted, a sharp edge, and the leaf spring lies flat up to this edge on the yoke. Similarly, the armature also forms at its free end a sharp edge over which the free end of the leaf spring, which carries a movable contact in the end portion, extends flat overlying. If such a relay falls from a certain height to the ground, the armature moves against the yoke and against the other fixed parts of the relay upon impact. Such movement may result in a corresponding impact direction to a plastic deformation of the spring, which causes an unintentional change in the electrical parameters of the relay beyond a reasonable level. So if, for example, the anchor on impact a movement perpendicular to the support plane of the leaf spring learns the yoke, the leaf spring can be bent over the yoke edge and plastically deformed. If the armature experiences a shock in a direction perpendicular thereto, ie in the direction of the coil axis or the yoke plane, then the contact leg of the leaf spring can be bent over the end edge of the free armature end and plastically deformed in the event of a correspondingly strong impact.

DE 295 01 303 U discloses a relay arrangement in which an armature spring is curved away in a portion from the support surface of the yoke, so that between the support and the spring, a gap is created. The relay is a construction with locking pins, which are formed on the armature and prevent deformation of the spring. In particular, one of the securing hooks strikes a bearing edge of the yoke limb in the event of an impact stress and thus prevents an excessive movement of the armature and thus an undesired deformation of the armature spring.

The aim of the present invention is to design a relay of the type mentioned constructively so that when impact stresses a permanent deformation of the leaf spring is avoided or at least greatly reduced in the effect.

This object is achieved according to the invention in a relay with the aforementioned design according to the features of claim 1.

In the construction of the relay according to the invention is thus ensured that the leaf spring, which usually extends in the relaxed state of the flat support portion substantially straight over the end of the carrier, in the region of this support end is not directly rests on an edge. Rather, the carrier is provided in this end region with a curved surface on which the leaf spring can roll during a shock first, or the leaf spring itself is concave curved away from the support surface in the rest state, so that it can roll on a flat surface of the support. In this rolling process, the impact energy is converted into an elastic deformation of the spring before the spring reaches an edge at the end of the carrier. About the curvature of the Abrollabschnittes thus necessarily occurring in the case of the relay deformation of the spring is influenced so that essentially only elastic deformations occur and plastic deformation, if they occur because of too wide tolerance of about an anchor stop but still be limited to a minimum.

wobei r den Krümmungsradius, d die Dicke der Blattfeder, σ_FB die Federbiegegrenze und E den Elastizitätsmodul der Blattfeder bezeichnen.Advantageously, the curvature of the roll-off section at least approximately follows a circular arc whose radius of curvature satisfies the following condition: $$r\ge \frac{d\cdot \mathrm{<figure-callout\; id="2"\; label="e"\; filenames="imgf0001.png"\; state="\{\{state\}\}">e</figure-callout>}}{2\cdot {\sigma }_{\mathit{FB}}}.$$

where r is the radius of curvature, d is the thickness of the leaf spring, σ _{FB is} the spring bending limit, and E is the elastic modulus of the leaf spring.

bewegen, ohne daß eine plastische Verformung eintritt. Um eine solche plastische Verformung auch bei noch stärkeren Stößen zu vermeiden, ist deshalb zweckmäßigerweise ein Anschlag vorzusehen, der nach einer Relativbewegung zwischen Blattfeder und Träger um den Weg s eine weitere Bewegung verhindert.When the length of the arcuate roll-off section is 1, the leaf spring may deflect by a distance when impacted against the free end of its carrier $$s=\frac{{\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="imgf0001.png"\; state="\{\{state\}\}">l</figure-callout>}}^2}{2\cdot r}$$

move without a plastic deformation occurs. In order to avoid such a plastic deformation even with stronger shocks, it is therefore expedient to provide a stop which, after a relative movement between the leaf spring and the carrier, prevents further movement around the path s.

Preferably, the carrier has the curved Abrollabschnitt. In this case, the curvature of the roll-off section may be formed by a bend of the carrier. In addition, it is also possible to form this curvature by a one-sided embossing of the carrier. This is particularly advantageous if the curvature is to be formed on the anchor as a carrier. In this case, the one-sided embossing also reduces the mass of the armature, resulting in a reduced moment of inertia. As already mentioned, however, a rolling-off section can also be formed by a bending of the leaf spring, which thereby receives a bias from the surface of the carrier.

As mentioned above, comes as a carrier, the yoke of the relay into consideration, on which the leaf spring is mounted to store the anchor at the free yoke end. In this case, it is expedient that the margin for the spring portion is limited by a stop for the armature in the longitudinal direction. If, however, the carrier is the armature of the relay to which the leaf spring is fastened in order to form a protruding contact spring section with a movable contact, then the clearance for this spring section is expediently limited by a stop transversely to the longitudinal direction of the armature. In both cases, the stop is expediently formed by molding on a main body of the relay.

Figur 1

ein erfindungsgemäß gestaltetes Relais in Draufsicht und

Figur 2

in schematisierter Detaildarstellung einen Träger (Anker oder Joch) mit einem konvex gekrümmten Blattfederabschnitt.

In the invention is explained below using an exemplary embodiment with reference to the drawing. It shows:

FIG. 1

an inventively designed relay in plan view and

FIG. 2

in a schematic detail representation of a carrier (armature or yoke) with a convex curved leaf spring portion.

The relay of Figure 1 has in the usual way designed as a base body bobbin 1, which carries a winding 2 between two flanges 3 and 4. In the flange 4, a contact arrangement with two mating contacts 5 (with terminals 5a) and a movable contact 6 is arranged, which is supported by a leaf spring 10 to be described. A core 7 extends in an invisible manner axially through the coil. It forms at one end a pole plate 8 and is connected at the opposite end to a first leg 21 of an angled yoke 20, the second leg 22 extends approximately parallel to the coil axis adjacent to the coil. At the free end of the yoke leg 22, an approximately plate-shaped armature 30 is mounted, which forms a working air gap with the pole plate 8.

The leaf spring 10, which serves in a conventional manner both as an anchor holding spring and as a contact spring, has a terminal leg 11 which is connected to a pin 11a. Another leg is attached as a mounting leg 12 on a flat support portion 23 of the yoke leg 22, the continuation extends in the same state in the same state as unsecured spring portion 13 over the free end 24 of the yoke leg 22 away, then arcuately spans the bearing end 31 of the armature 30 and is secured with a further attachment portion 14 on a support portion 33 of the armature 30. With an unattached spring portion 15 which carries the movable contact 6 at its free end, the extension of the attachment portion 14 extends beyond the free end 32 of the armature 30 into the region between the two fixed mating contacts 5. The attachment portion 12 is by a welded connection with the support portion 23 of the yoke, the attachment portion 14 is connected via a rivet connection 35 with the support portion 34 of the armature 30. In both cases, another type of attachment would be conceivable.

If the relay now experiences strong acceleration as a result of an impact, then both the spring section 13 in the region of the yoke end 24 and the spring section 15 could be plastically deformed in the region of the armature end 32, if these ends were each formed in the conventional manner as edges of a flat section , According to the invention, however, the free end portion of the yoke leg 22 is convexly curved by a bend of the yoke, so that a Abrollabschnitt 25 is formed with the length 11. In the same way, the free end of the armature is also convexly curved by embossing on its upper side, so that there is formed a Abrollabschnitt 35 with the length 12. In both cases results between the Abrollbereich and the leaf spring, a wedge-shaped Abrollbereich.

To explain the function of the design according to the invention of the yoke and the armature, two possible collision directions x and y are considered, in which collision impacts each cause a relative movement of the movable relay parts, namely the armature 30 and the leaf spring 10:

If a deflection of the armature in the x-direction caused by a shock occurs, the unsecured spring section 15 can roll along the rolling section 35 and bend elastically without the bending limit of the spring material being exceeded. By a stop 9 for the armature in the housing is finally ensured that the armature comes to a stop before the spring portion 15 has reached the anchor end 32. It can therefore no longer be plastically bent over the remaining edge at the anchor end.

If, on the other hand, a shock occurs by which the armature is deflected in its longitudinal direction, namely in the y direction, the spring section 13 can roll along the rolling section 25 of the yoke and bend elastically without exceeding the bending limit of the spring material. Again, there is a limit stop 19 in the housing, in which the free anchor end 32 abuts before the spring portion 13 has reached the angular yoke end 24 in tolerance-safe distance.

The rolling portions 25 and 35 preferably have a circular arc-shaped curvature, wherein the radius r1 of the roll-off portion 25 and the radius r2 of the roll-off portion 35 each satisfy the above-mentioned condition: $$r\ge \frac{d\cdot \mathrm{<figure-callout\; id="2"\; label="e"\; filenames="imgf0001.png"\; state="\{\{state\}\}">e</figure-callout>}}{2\cdot {\sigma }_{\mathit{FB}}}$$

The range of motion between the spring portion 13 and the armature end 24 is denoted by s1, the range of motion between the spring portion 15 and the armature end 32 with s2. According to this scope is also the way s dimensioned, the anchor in both directions until it stops Can cover 9 and 19, without a plastic deformation of the leaf spring occurs. For s1 and s2 then applies $$s1=\frac{{l1}^2}{2\cdot r1}\mathrm{and}s2=\frac{{l2}^2}{2\cdot r2}\mathrm{,}$$

As mentioned above, the Abrollbereich can also be formed by the fact that the leaf spring itself is concave from its support, the armature or the yoke, away. Such an embodiment is shown schematically in FIG. There, a carrier 40 is shown, which may be both an anchor and a yoke with a support portion 43, on which a leaf spring 50 is mounted in its function as an anchor bearing spring or as a contact spring with mounting portion 51. This leaf spring has a over the free end 41 of the carrier 40 projecting spring portion 52 which forms a convexly curved Abrollabschnitt 55 of the length 13, whereby a wedge-shaped Abrollbereich with the length 13 is formed in this case. Also in this case, therefore, the spring can roll on a relative movement over the entire Abrollbereich on the carrier 40.

Of course, it will be clear to a person skilled in the art that a roll-off section on the yoke can be used independently with an armature spring and a roll-off section on the armature end with a contact spring, if, for example, no common leaf spring is provided for the armature bearing and for the contacting.

Claims (8)

1. Electromagnetic relay comprising a contact arrangement and a magnet system, said magnet system comprising a yoke (20) and an armature (30) movably mounted on the yoke, and also comprising a leaf spring (10; 50) in the form of an armature bearing spring and/or a spring contact, which leaf spring has a fastening section (12; 14) secured to lie planarly on a planar seating section (23; 33) of a rigid carrier formed by the yoke (20) or the armature (30) and having an adjoining unsecured spring section (13; 15) extending beyond a free end (24; 32) of the carrier (22; 30; 40), said spring section (13; 15; 51) having a predetermined motion latitude (s1; s2; s3) extending perpendicularly to the plane of the fastening section (12; 14),
   characterised in that
   between the seating section (23; 33; 43) and the free end (24; 32; 41) of the carrier (22; 30; 40) a roll-off region having a wedge shape in quiescent condition is formed for the leaf spring (10), said roll-off region being formed by a convex curvature of a roll-off section (25; 35; 55) of the carrier (22; 30) and/or the leaf spring (50) away from the plane of the seating section (23; 33; 43), constructed in such a way that under the effect of impact energy this energy converted into elastic deformation of the leaf spring in a roll-off action, before the leaf spring reaches an edge at the end of the carrier.
2. Relay according to claim 1, characterised in that the roll-off section (25; 35; 55) has at least approximately one radius of curvature (r1; r2; r3) that satisfies the following condition: $$r\ge \frac{d\cdot E}{2\cdot {\sigma }_{\mathit{FB}}}$$

   

   
   where

   r = the radius of curvature of the roll-off section;

   d = the thickness of the leaf spring;

   σ_FB = the spring bending limit of the leaf spring; and

   E = the modulus of elasticity of the leaf spring.
3. Relay according to claim 2, characterised in that the motion latitude (s1; s2; s3) between the leaf spring (10; 50) and the carrier (22; 30; 40) at the open end of the roll-off region is limited by a fixed stop (9; 19) according to the following relationship: $$s=\frac{l^2}{2\cdot r}$$

   

   
   where

   s = the motion latitude (s1; s2; s3) of the leaf spring relative to the free end of the carrier;

   l = the length (11; 12; 13) of the roll-off section and

   r = the radius of curvature (r1; r2; r3).
4. Relay according to any one of claims 1 to 3, characterised in that the curvature of the roll-off section (25; 35) is formed by bending of the carrier (22).
5. Relay according to any one of claims 1 to 3, characterised in that the curvature of the roll-off section (35) is formed by one-sided moulding of the carrier (22).
6. Relay according to any one of claims 1 to 3, characterised in that the curvature of the roll-off section (55) is formed by forward bending of the leaf spring (50).
7. Relay according to any one of claims 1 to 6, characterised in that the carrier is the yoke (20) of the relay, in that the armature (30) of the relay is secured to the projecting spring section (13) and in that the latitude (s1) for the spring section (13) is limited by a stop (19) for the armature (30) in the longitudinal direction thereof.
8. Relay according to any one of claims 1 to 7, characterised in that the carrier is the armature (30) of the relay, in that a movable contact (6) is secured to the projecting spring section (15) and in that the latitude (s2) for the spring section (15) is limited by a stop (9) transverse to the longitudinal direction of the armature (30).

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