EP1722382B1 - Contact arrangement for a relay - Google Patents

Description

The invention relates to a contact arrangement for a relay with a contact head, which is equipped with a crown, in particular for "dry" switching loads, and a relay with such a contact arrangement.

From the JP 56-107418 For example, an electrical contact head and a method for manufacturing the same is known. The drawing of this document shows a circular disc with nine points, which are arranged along the circumference of the circular disc. These prongs are used for fastening by means of cold welding of the contact head on a contact head carrier.

From the DE 31 28 929 is a contact arrangement for switching devices known. In this contact arrangement, a contact head has a crown with a circularly closed contact line. A second, cooperating with this contact head contact head also has a line of contact. This can be rectilinear, or else circular in shape as a crown. The contact lines of the two cooperating contact heads intersect, so that in each case two crossing points arise at which the contact heads can touch.

From the DD 150 669 For example, an electrical contact pair is known in which the contact heads have circular outlines and are symmetrical about an axis through the circular center of the outline. The contact surface of such a contact head is formed circumferentially convex at the edge. This convex bead merges into a concave surface towards the center. The bead may have recesses. The other contact may be convex. With a contact pair formed in this way, the contact resistance and the burnup can be reduced. Further advantages are a high resistance with respect to the asymmetry of the switching point, a cooling of the contact surfaces as a result of their enlargement, an extension of the overall service life and an increase in the reliability.

From the German utility model DE 90 06 430.5 U a relay is known which is used in so-called. Dry switching circuits or circuits with low load. To reduce or avoid the disadvantages which are due to the external film resistance, it is proposed that one or more in the direction of the other contact out in relief protruding elevations are provided on one or both of the contacts of a contact pair. With these, the contact surface is greatly reduced at the contact point and thereby increases the contact pressure. The elevations are formed by embossing a curved contact surface centric on this and are only increased by 5 to 100, preferably by 10 to 50 microns relative to the other contact surface.

It is the object of the present invention to propose a relay, a contact head or a contact arrangement, with which or which the contact reliability in "dry" switching load (without switching sparking when switching) is high. In particular, the highest possible specific contact pressure at the contact points of two contact heads and at the same time certainly a two-point contact should be achieved. In particular, the contact head with a second contact head, which is formed crownless and smooth, should strike at not less than two small-area contact points.

This object is achieved by the subject matters of the independent claims.

A relay according to the invention has in one of DE 90 06 430.5 U known manner at least one contact arrangement for the dry switching of a circuit. In a contact arrangement according to the invention, a first contact head is present in known manner, which has an annular crown, and a second contact head which cooperates with a crownless contact surface with the first contact head. The diameter of the crown is less than the diameter of the contact surface of the second contact head. One of the contact heads is arranged on a contact spring and movable. In the closed position, the two contact heads are inclined to each other, so that the crown is not circumferentially applied to the mating contact, but is pressed against only a small circle section. This achieves a relatively high contact pressure.

The object of the invention is inventively achieved in that on the one hand, the crown is formed by a plurality or plurality of prongs, which are separated by interruptions in the crown, and on the other the contact spring is formed twistable. This ensures that in the closed position always two prongs of the first contact head rest on the contact surface of the second contact head.

This also ensures that a single, the contact heads separating grain at the point of contact of the two contact heads can not prevent the electrical contact altogether. The arranged on the contact spring contact head is rotated in this case about the axis of the contact spring by the contact spring twists until a second point of the crown rests against the contact surface of the mating contact and therefore can flow current. Thus, a two-point contact is achieved, which is safer than the one-point contact, which in the DE 90 06 430.5 U is realized.

In a preferred embodiment, the prongs are arranged at regular intervals at a distance from the circumference of the contact head. The distance to the circumference of the contact head guarantees that the prongs fall with the same size counter contact into the interior of the contact surface and not get caught on the edge of the contact surface with the mating contact.

The crown has a diameter that is between one third and two thirds of the diameter of the first contact head. Preferably, the diameter of the crown has a maximum diameter of the Nietstumpfs, more preferably it corresponds to the diameter of the Nietstumpfs. This allows a large force to be exerted on the location of the rivet head on which the crown is to be formed by cold deformation.

For producing a crown contact head by means of a cold-forming process, the contact head is first formed with an annular crown, and subsequently are formed in this annular crown, eg with a spokes wheel-like punch interruptions. This results in a crown of alternating spikes and interruptions between the spikes. Conveniently, the interruptions are formed only when riveting the contact head in a contact head carrier. This allows the position of the serrations in relation to the contact head carrier, ie, for example, a contact spring or a stationary plate, to always be aligned in the same way. Advantageously, an interruption is formed on an axis of the contact spring. The crown does not need to form a whole circle, but can only around the axis of the contact spring be present around, but missing in a greater lateral distance to this axis, since the contact head will only twist so far until the next point rests against the mating contact.

In a contact head for a contact arrangement of a relay having a contact surface enclosing, opposite the contact surface projecting crown which forms a contact edge, the edge of the projecting crown is interrupted according to the invention at a plurality of points, so that prongs and spaces are formed between the prongs.

If such a toothed crown pressed onto a smooth, flat or curved contact surface of a second contact head of the contact arrangement, a small spring force is sufficient to achieve a high specific surface pressure at the contact points. This high contact pressure is achieved because the spikes abut small contact points on the smooth contact surface. In addition, the two contact heads are securely against each other at two points of contact, since the contact head with serrated crown will only wear away the spring pressure torsionally stable when the contact heads touch each other at two spaced locations. Both of these locations are very small in the case of the contact heads according to the invention.

The crown is expediently formed on the circumference of the contact head by a multiplicity of teeth, which taper increasingly at a distance from the contact surface. The taper can be designed to run out, so that the contact edge razor-sharp to 0.1 mm wide. Due to the tapering of the teeth, these have a stable base despite minimal dimension of the contact edge, so that the teeth do not yield to the contact pressure and therefore do not deform. Ensures the plurality of prongs that the arrangement of the contact head on the leaf spring of the contact can be done in any orientation of the prongs and in any possible arrangement even with very little distortion of the leaf spring two prongs make a secure two-point contact.

The contact edge preferably has a length of 0.01 to 0.7 millimeters, preferably 0.01 to 0.2 millimeters, particularly preferably 0.02 to 0.1 mm between the interruptions. These measures limit the maximum size of the contact surface of a contact head. However, the contact area of a single prong may be even less than the length times width of the contact edge two prongs, since in most cases, each prong strikes only with a single end point of the two present at each jaw endpoints of the contact edge on the opposite contact head.

The prongs are expediently arranged at regular intervals from one another on the circumference of the contact head. As a result, no position of the contact head is preferable to another, but each position is equivalent to the other. The number of points is dependent on the circumference of the crown and, depending on the diameter of the crown, preferably in a range of 10 to 60. With a diameter of the crown of about 2.4 mm are preferably from 24 to 40 points before.

The prongs have to the enclosed by the crown contact surface out with advantage in each case a leaking shaped edge. This reduces the occurrence of cracks (e.g., stress cracks) in the contact head.

The area enclosed by the crown contact surface is advantageously smooth and flat or slightly cambered formed. A central wart may be formed on the contact surface to provide, in use of the head, a "wet-switching", i. burning contact as much as possible verschleissbares material to exhibit.

The contact head is expediently a rivet head with a finished molded contact body with crown and on the back of it a shapable rivet stub. To rivet the rivet head, a rivet die can be used, as it is used for untoothed crown contact heads.

However, it is also possible to provide weld-on contacts or solder-on contacts with a crown that is jagged in accordance with the invention.

In a contact arrangement for or in a relay with at least two contact heads, in which a first contact head is formed with a contact surface enclosing a projecting crown, which crown forms a contact edge, according to the invention, the edge of the projecting crown is interrupted at a plurality of locations, whereby spikes are formed. The contact heads are conveniently arranged on contact springs, in particular riveted, soldered or welded. These contact springs are Leaf springs, which join a certain twist. They therefore increase the certainty that in any case a two-point contact is ensured.

The second, cooperating with the first contact head contact head is, however, advantageously formed crownless. It merely forms a smooth counterpart, against which the first contact head strikes the crown at a certain angle. The second contact head therefore has best a smooth, planar or slightly curved contact surface.

The first and the second contact head are expediently arranged relative to each other such that the first contact head contacts the crown on the contact surface of the second contact head at a distance from an edge of this contact surface. This can e.g. be achieved in that the second contact head has a larger diameter than the first contact head. However, the contact heads can also be eccentric to each other. In contact position then only needs the crown contact with serrated crown to be inclined relative to the second contact head. The foremost point of the inclined crown must then abut against the contact surface of the second contact head.

Fig. 1

zeigt eine perspektivische Zeichnung eines Nietkopfs mit gezackter Krone

Fig. 2

zeigt eine Kontaktanordnung mit einem solchen Nietkopf

Fig. 3

zeigt die Kontaktanordnung nach Figur 2 in geschossener Stellung,

Fig. 4

zeigt eine Wechselkontaktanordnung mit zwei ruhenden, erfindungsgemässen Kontaktköpfen und beidseitig je einem glatten Wechselkontaktkopf,

Fig. 5

zeigt eine Wechselkontaktanordnung mit einem Wechselkontaktkopf mit einseitig einem erfindungsgemässen Kontaktkopf und auf der gegenüberliegenden Seite einem glatten, geschlagenen Kontaktkopf,

Fig. 6

zeigt eine Seitenansicht eines Kontaktkopfes mit einer Zackenkrone,

Fig. 7

zeigt den Kontaktkopf gemäss Fig. 6 in einer Frontalansicht,

Fig. 8

zeigt den Kontaktkopf perspektivisch dargestellt,

Fig. 9

zeigt eine Ansicht eines Kontaktkopfs mit teilweiser Zackenkrone,

Fig. 10

zeigt den Kontaktkopf gemäss Figur 9 in einer Frontalansicht,

Fig. 11

zeigt denselben Kontaktkopf perspektivisch dargestellt,

Fig. 12

zeigt eine Ansicht eines Kontaktkopfes mit Zacken an vier Ecken,

Fig. 13

zeigt den Kontaktkopf gemäss Fig. 9 in einer Frontalansicht,

Fig. 14

zeigt denselben Kontaktkopf perspektivisch dargestellt

Fig. 15

zeigt einen Öffner in geschlossenem Zustand,

Fig. 16

zeigt einen Schliesser in geschlossenem Zustand,

Fig. 17

zeigt eine perspektivische Darstellung eines Relais gemäss der Erfindung.

Brief description of the figures:

Fig. 1

shows a perspective drawing of a rivet head with serrated crown

Fig. 2

shows a contact arrangement with such a rivet head

Fig. 3

shows the contact arrangement after FIG. 2 in a shot position,

Fig. 4

shows a changeover contact arrangement with two stationary contact heads according to the invention and one each on both sides with a smooth changeover contact head,

Fig. 5

1 shows a changeover contact arrangement with a replaceable contact head with a contact head according to the invention on one side and a smooth, beaten contact head on the opposite side,

Fig. 6

shows a side view of a contact head with a toothed crown,

Fig. 7

shows the contact head according to Fig. 6 in a frontal view,

Fig. 8

shows the contact head shown in perspective,

Fig. 9

shows a view of a contact head with a partial tooth crown,

Fig. 10

shows the contact head according to FIG. 9 in a frontal view,

Fig. 11

shows the same contact head shown in perspective,

Fig. 12

shows a view of a contact head with teeth at four corners,

Fig. 13

shows the contact head according to Fig. 9 in a frontal view,

Fig. 14

shows the same contact head shown in perspective

Fig. 15

shows an opener in the closed state,

Fig. 16

shows a closer in the closed state,

Fig. 17

shows a perspective view of a relay according to the invention.

The in FIG. 1 shown contact head 11 is a rivet head. He therefore has a contact body 13 with a contact surface 15, which is surrounded by a crown 17. He has the back of the contact body 13 arranged a Nietstumpf 19, which must be inserted and beaten for fixing the contact head 11 to a leaf spring through a hole in the leaf spring. In the illustrated contact head 11, the crown 17 is formed of 40 teeth 21. However, this number depends on the crown circumference and the fineness of the teeth. Between the prongs 21 of the contact head is planar, both the area enclosed by the teeth contact surface and in the spaces between two adjacent prongs 21. However, the contact head could also be slightly cambered or equipped with a conventional wart. However, the elevation in the central region of the contact surface should not project beyond the plane formed by the tips of the prongs 21.

The prongs 21 have a tip, which is formed by an edge. This edge lies on a circular line and has at each point 21 a length of, for example, 0.02 mm. The length and width of the edge can have larger dimensions. From this edge, the flanks of the teeth 21 are formed sloping sloping towards the contact surface 15. The flank, which is inclined toward the center of the head 11, is designed to be concavely concave in each case.

In the in FIGS. 2 and 3 illustrated contact arrangement are opposed to two cooperating spring contacts. Two leaf springs 23 each carry a contact head. Of these contact heads, only one is a contact head 11 according to the invention with a serrated crown. The other contact head 25 is smooth. A crown on the second contact head 25 would increase the risk of entanglement of the two contact heads.

The contact arrangement according to these two figures may be a make or break contact. When striking the two contact heads 11 and 25 to each other a tangential movement (scouring movement) of the two heads against each other, thanks to the contact point undergoes a mechanical cleaning. If the two contact heads abut one another, the serrated crown lies with two points on the flat or slightly convexly curved contact surface of the smooth contact head 25. These prongs 21 are applied with a very small area, so that even with low contact force of the spring, a high specific surface pressure (a high contact pressure) sets.

As in FIGS. 4 and 5 shown, can also change contacts equipped with inventive contact heads. Although a trained head with a toothed crown is theoretically possible, it can practically be ruled out. Beaten contact heads are therefore formed in these figures as smooth contact heads 25. In FIG. 4 the two stationary contact springs are each provided with a contact head according to the invention. Between these, a movable contact spring with a double contact head 31 is formed. This double contact head 31 is prefabricated on one side and beaten on the other side. In FIG. 5 the middle and movable contact spring is also formed with a double head. However, this is provided on the prefabricated side with a serrated crown 17. On the beaten side, however, the head is smooth. The flat or curved, beaten head is a stop for the stationary contact head 11 according to the invention. The movable contact head 11 with toothed crown 17 strikes against a smooth, prefabricated contact head 25.

The diameter of the cooperating with the novel contact heads smooth contact heads is shown in the examples consistently larger than the diameter of the serrated crown 17. In a suitable position of the contact heads, however, this is not required. The only condition is that the teeth of the tooth crown touch the adjacent contact head on a nearly smooth contact surface.

The in the FIGS. 6 to 8 shown contact head 11 'has a crown 17' of a plurality of prongs 21 '. The crown is formed at a distance from the circumference of the contact head. The diameter of the crown corresponds to the pressure gauge of the rivet stub. The crown diameter measures just over half of the head diameter.

The teeth 21 'are sharp-edged. The rivet head 11 'has a planar contact surface 15, on which the prongs 21' are arranged. The prongs 21 'are about 30 microns high (15 to 60, preferably 20 to 40 microns). The distance between two prongs is about 10 times the height of the prong (about 0, 3 mm, preferred range: 0.2 to 0.5 mm). The width of the serrated tip in the direction of the crown circumference is about half as wide as the width of the spacing between the serrations (preferred range 0.1 to 0.3 mm).

The prongs are made by cold breaking the breaks between the prongs of a contact head with a ring crown. The material of the crown is urged at the interruptions in the body of the contact head and in the adjacent teeth. As a result, adjacent to the interruption edges of a serration 21 'are slightly increased. These edges then form the point of contact with a planar contact surface of a mating contact.

The formation of the interruptions is preferably carried out in a single process step together with the riveting of the contact head with a contact head carrier, ie a contact spring of a movable or a plate of a fixed contact.

Since such a method of forming the serrated crown of the contact head defines the positioning of the serrations in relation to the contact spring or the plate, it is possible to dispense with those serrations in the serrated crown which will certainly not interact with a countercontact. It can be waived there on the training of interruptions, or the crown altogether be omitted or pressed away. The contact heads according to FIGS. 6 to 11 Therefore, if made by the preferred method, they are not erroneously located on a contact head carrier. If the rivet stub was not pressed in, the crown would also have to be shown without a pin.

In the contact head according to FIGS. 9 to 11 the axis of a contact head carrier is shown as a dash-dotted line. There are only two prongs 21 'laterally formed subsequent to this axis. When mounting the contact head on a contact head carrier only 8 prongs 21 'are formed in this embodiment. In the assembled relay then two of the axis closest teeth 21 'work together with the mating contact. Depending on the nature of the mating contact, it is the Foot end of the contact head mounted on a contact spring remote or closer two teeth.

In order to obtain a larger lever and thus a greater force for the twisting of the contact spring, the contact head according to FIGS. 9 to 11 also be mounted so that the axis of the contact spring extends along the dashed line. Then the closest of this axis contact heads are arranged at a relatively large distance from the axis. Therefore, a larger, the contact spring twisting force results when the crown contact rests only on a point.

In FIGS. 12, 13 and 14 a contact head is shown, which has only 8 teeth, which are arranged in pairs in the corners of a square approximated rectangle. It can also be formed only four points, in each corner one.

If a contact element consisting of a contact head and a contact head carrier can only be used for a make or break contact, but not for both types of contacts, the upper or lower contacts can also be dispensed with. The symmetrical design with respect to an axis perpendicular to the axis of the contact spring allows to use the same contact members in closers and openers.

In FIG. 13 is also shown schematically that the areas in which the crown is compressed to achieve an interruption between two teeth, production-related conditions relative to the contact surface slightly increased, or can be deepened.

In FIGS. 15 and 16 Two different contact pairs are shown. When closed normally closed according to FIG. 15 are the closer to the foot of the contact spring teeth on the mating contact. When closed, according to FIG. 16 The more remote from the foot pikes at the mating contact. The mating contact is slightly cambered. The contact surface, which is arched towards the crown contact, has a curvature height in the interior of a central region with the radius of the crown that is less than the height of the points. As a result, the prongs always rest against the curved contact surface of the mating contact.

In FIG. 16 In addition, the movement sequence of the contact is shown. The drive end of the contact spring is overrun (straight arrow). This means that the drive comb in the relay pushes the drive end further against the mating contact, as is necessary for a contact of the two contact heads. In this case, the contact spring is bent further (circular arrow), after the contact head rests with two edges of the teeth already on the contact surface of the mating contact. The contact head makes the movement of the further bending contact spring with and scratched so with the two adjacent edges on the surface of the mating contact. This ensures that a possibly present on the contact heads, separating layer is durchschabt.

The FIG. 17 shows a relay according to the invention with a plurality of contacts in which a toothed crown contact head and a crownless mating contact cooperate. The relay shown has two openers 33 and four closers 35. Such relays can be designed in two rows as shown, or even only single row. In a single-row relay, only one opener 33 is present, but one to three make 35. Off FIG. 14 is also the drive 37, the armature 39 and the drive comb 41 can be seen, by means of which the movable contact springs 23 can be moved.

Briefly, the invention relates to a pair of contacts of a relay, with a contact head, which has a crown 17 which encloses a contact surface 15 and protrudes with respect to the contact surface. This crown has an edge which is interrupted at a plurality of locations, whereby prongs 21 and spaces between the prongs 21 are formed. This results in that the crown contact head 11 touches a smooth, crownless adjacent contact head in each case despite low spring force with high contact pressure to safely two small-area contact points. As a result, the contact reliability can be increased with dry switching load over conventional crown contacts.

Claims (14)

1. Contact arrangement for dry switching of an electric circuit, contact arrangement for which

   - a first contact head (11) exists that has a ring-shaped crown (17),

   - a second contact head (25) that cooperates with the first contact head (11) with a contact face configured without a crown,

   - the diameter of the crown (17) is smaller than the diameter of the contact face of the second contact head,

   - one of the contact heads is placed on a contact spring and is movable and

   - in closed position both contact heads (11, 25) are inclined to each other,

   characterized in

   - that the crown (17) is formed by a multitude of teeth (21) separated by interruptions and

   - that the contact spring (23) is configured twistable so that in closed position at least two teeth of the first contact head (11) bear on the contact face of the second contact head (25).
2. Contact arrangement according to claim 1, characterized in that the teeth have contact edges with a length of 0,01 to 0,7 millimeter, preferably of 0,01 to 0,2 millimeter, particularly preferably of 0,02 to 0,1 millimeter.
3. Contact arrangement according to one of the preceding claims, characterized in that the teeth (21) are placed at regular distances from each other.
4. Contact arrangement according to one of the preceding claims, characterized in that the teeth (21) are placed on the periphery of the contact head (11).
5. Contact arrangement according to one of the claims 1 to 3, characterized in that the teeth (21) are placed at a distance from the periphery of the contact head (11).
6. Contact arrangement according to one of the preceding claims, characterized in that the contact face (17) enclosed by the crown (17) is configured with a flat surface.
7. Contact arrangement according to one of the preceding claims, characterized in that the contact head is a rivet head with a ready molded contact body (13), has on the front side thereof a crown (17) with teeth (21) and is riveted on the back side thereof with a rivet stub (19) on a contact head support.
8. Contact arrangement according to one of the preceding claims, characterized in that the second contact head (25) has a slightly vaulted contact face.
9. Contact arrangement according to one of the preceding claims, characterized in that the second contact head (25) has a bigger diameter than the first contact head (11).
10. Contact arrangement according to one of the preceding claims, characterized in that the crown has a diameter that is between one third and two thirds of the diameter of the first contact head.
11. Contact arrangement according to one of the claims 7 to 10, characterized in that the diameter of the crown is at the most the diameter of the rivet stub, preferably corresponds to the diameter of the rivet stub.
12. Relay with at least one contact arrangement according to one of the preceding claims.
13. Method for producing a crown contact head for which the contact head is cold formed, characterized in that during the cold forming of the contact head the contact head is formed with a circular ring-shaped crown and subsequently breaks are formed in this circular ring-shaped crown, for example with a spoked wheel type punch so that teeth and breaks between the teeth are alternately formed.
14. Method according to claim 13, characterized in that the breaks between the teeth are formed into the crown during the riveting of the contact head in a contact head support.

Images