WO2009141315A1

WO2009141315A1 - Relay

Info

Publication number: WO2009141315A1
Application number: PCT/EP2009/056018
Authority: WO
Inventors: Rudolf Mikl
Original assignee: Tyco Electronics Austria Gmbh
Priority date: 2008-05-23
Filing date: 2009-05-18
Publication date: 2009-11-26
Also published as: DE102008024940B3

Abstract

The invention relates to a relay comprising a magnet system (3, 12) with which an armature (5) can be brought into a first position or second position, and comprising at least one make contact (2) and at least one changeover contact (6) which can be separated from the make contact by means of spring force, an actuating element (4) being provided which transmits the movement of the armature onto the changeover contact such that in a first position of the armature there is exerted on the changeover contact a tensile force by which the changeover contact can be moved towards the make contact against the spring force, the actuating element being arranged to exert a compressive force onto the changeover contact for opening fused contacts in a second position of the armature in that the actuating element is engaged on the changeover contact in a variable spacing such that in the first position of the armature, a spacing is formed such that when the armature is moved from the first position into the second position, the actuating element strikes the fused changeover contact shortly before the armature reaches the second position.

Description

RELAY

The invention relates to a relay comprising a magnet system with which an armature can be brought into a first position or second position, and comprising at least one make contact and at least one changeover contact which can be separated from the make contact by means of spring force, an actuating element being provided which transmits the movement of the armature onto the changeover contact such that in a first position of the armature there is exerted on the changeover contact a tensile force by which the changeover contact can be moved towards the make contact against the spring force.

Relays of the type mentioned at the outset are used, for example in motor vehicles to connect consumers which have a high current consumption. For this purpose, a break contact can also be provided in addition to a make contact, such that the changeover contact of the relay can switch the flow of current between break contact and make contact. Furthermore, a plurality of make, break and changeover contacts can be provided, for example to connect a plurality of consumers or a plurality of connecting contacts of a single consumer with a single relay.

In the known relays, when the changeover contact is separated from the make contact under electric load, it sometimes happens that immediately after the contact points have been separated, an electric arc is produced which is fed by the operating current of the connected consumer. The thermal energy of this electric arc can result in the contact points melting on the make contact and the changeover contact. This melting can cause the contacts to become fused together. Separation of the contact points and thus connection of the electric consumer then becomes impossible.

It is known from the prior art to guide the changeover contact with spring force towards a break contact or a stop face in order to detach two fused contacts. If the holding force of the fusion is less than the spring force, the fusion can be forced apart by the spring and the contacts can be separated.

Furthermore, it is known to release a fusion of the contact elements by a shock to the relay, for example by striking with a hard object. However, the application of such a shock requires intervention by the user or maintenance staff. Thus, it is impossible to reliably separate the contacts in this way in order to connect safety-relevant components.

Based on this prior art, the object of the invention is to develop a known relay of the type mentioned at the outset such that it is possible to reliably force apart a fusion of make contact and changeover contact without the intervention of a user.

The object is achieved according to the invention by a relay which comprises a magnet system with which an armature can be brought into a first position or second position, and comprises at least one make contact and at least one changeover contact which can be separated from the make contact by means of spring force. In this arrangement, an actuating element is provided which transmits the movement of the armature onto the changeover contact, such that in a first position of the armature there is exerted on the changeover contact a tensile force by which the changeover contact can be moved towards the make contact against the spring force, the actuating element being arranged to exert a compressive force onto the changeover contact in a second position of the armature in order to open fused contacts, in that the actuating element engages on the changeover contact in a variable spacing such that in the first position of the armature, a spacing is formed such that when the armature is moved from the first position into the second position, the actuating element strikes the fused changeover contact shortly before the armature reaches the second position.

According to the invention, it has been found that it is possible to develop a prior art relay in which in order to produce an electrical contact, the changeover contact is guided onto the make contact by a tensile force produced by the magnet system against a spring force, such that a compressive force for forcing apart a fusion can be exerted on the changeover contact by means of the energy stored in the magnet system. In this respect, the actuating element engages at a spacing on the changeover contact in order to transmit a compressive force such that the compressive force is imprinted on the changeover contact by the magnet system only when the changeover contact slides back, not by spring force alone, onto the break contact or a stop face.

The features according to the invention of the relay for forcing apart a fusion can be used both for vertical and horizontal housing configurations of a relay. Furthermore, the magnet system of the relay can be configured as a mono-stable or as a bi-stable magnet system. However, the relay is more preferably used in mono-stable magnet systems which merely provide a tensile force for contact closure and the contacts are separated through spring force alone when the coil current is disconnected.

On the one hand, in order to transmit onto the changeover contact the tensile force which closes the contact during each contact closure, while only exerting the compressive force necessary for opening fused contacts if the contact elements are fused, it is proposed according to the invention that the actuating element engages in a variable spacing on the changeover contact. In one embodiment of the invention, a variable spacing of this type can be provided by introducing both forces via separate stop faces on the changeover contact. Furthermore, there are provided on the actuating element different stop faces which can be formed, for example by recesses, noses or slots in the actuating element. As a result of the relative position of the engaging surfaces of the actuating element with respect to one another, it is possible to adjust the desired time or the desired armature position at/in which the compressive force is exerted on the changeover contact.

In order to increase the energy available for releasing fused contacts, it is proposed in a development of the invention to accelerate the armature and the actuating element when the contact is separated by spring force and, if the contact elements are fused together, to transmit the stored kinetic energy onto the changeover contact by striking the actuating element against the changeover contact. For this purpose, it is possible to provide on a case by case basis a distinct spring element or the same spring element which also moves the changeover contact into its rest position. In this respect, to increase the kinetic energy of the actuating element and of the armature, it is provided that these components initially undergo a free acceleration during which they are not engaged with the changeover contact. The actuating element only engages on the changeover contact to exert a compressive force shortly before the armature and the actuating element have reached the end position which separates the changeover contact and the make contact. In this respect, the time or position of engagement is to be selected such that the remaining residual path of the actuating element and armature is still sufficient to move the fused changeover contact into its rest position. On the other hand, the engagement is to take place at such a late stage that the actuating element and the armature secured thereto have attained as much kinetic energy as possible. A person skilled in the art will weigh up these two requirements against one another and will then make a suitable optimisation.

The invention will be described in detail in the following with reference to figures without restricting the general inventive concept.

Fig. 1 is an overview of some components of the relay according to the invention in a first view.

Fig. 2 is an overview of some components of the relay according to the invention in a second view.

Fig. 3 is a detailed view of the armature and the changeover contact of a relay according to the invention.

Figs. 4 to 6 show the relative positions of the actuating element and the changeover contact for a closed, open and fused contact. Fig 1 shows the functionally essential components of a relay according to the invention and their relative position to one another. In addition to these components, further components can also be present, for example a housing, cable or circuit board connections, additional pairs of contacts or the like. The invention does not teach the adherence to a specific construction principle, a specific number of contacts or a housing configuration as a solution principle.

In all cases, the relay according to the invention comprises a make contact 2 and a changeover contact 6. Thus, during operation of a consumer which is connected to the relay, a current flows from the make contact 2 to the changeover contact 6, or vice versa. To disconnect the consumer, the coil current through the coil 12 of the magnet system is disconnected. After the tensile force produced by the magnet system has ceased, the changeover contact 6 is positioned onto a break contact 1 by spring force. If an electrical consumer is also connected to the break contact 1 , the illustrated relay operates as a change-over switch. However, from case to case, it is also possible to provide a simple stop instead of the break contact 1, which stop can be made of metal or plastics material and onto which the changeover contact is positioned.

In order to produce a spring force, the changeover contact 6 is configured as a leaf spring. From case to case, a person skilled in the art will also consider moving the changeover contact with other spring elements in the direction of the break contact 1 , for example by means of helical springs or resilient plastics material elements. Plastics material elements of this type can be part of a housing.

The changeover contact 6 is mounted so that it can rotate, for example in a suitable housing groove, at its end opposite the contact elements. The changeover contact 6 is then pivoted in this flexible mounting when the circuit is closed and opened.

A magnet system is provided to move the changeover contact 6 onto the make contact 2. This magnet system consists of an approximately U-shaped yoke 3 and a magnet coil 12 attached thereto. In Fig. 1, the magnet coil 12 is covered by the yoke 3. Therefore, the magnet system will be explained in detail with reference to Fig. 2. Located at the end of the magnet coil 12 is a holding element 13, for example in the form of a plastics material moulding. The armature 5 is mounted pivotally in the holding element 13. When current flows through the coil 12, a magnetic field is generated in the coil 12 and the yoke 3. This magnetic field draws the armature 5 onto the free pole 7 of the U-shaped yoke 3 in order to close the magnetic flow via the armature 5. The movement of the armature 5 is transmitted onto the changeover contact 6 by an actuating element 4.

Fig. 1 shows that the actuating element 4 has first openings 14 by which the actuating element 4 is locked on the armature 5. The actuating element 4 also has two securing clips 15 to hold the actuating element 4 securely on the armature 5. The actuating element 4 can be produced integrally, for example as a plastics material moulding. The actuating element 4 is more preferably produced in an injection moulding process.

On its side opposite the armature, the actuating element 4 has two recesses 10 and 11. The recesses 10 and 11 are used to couple the actuating element 4 with the changeover contact 6.

When the armature 5 moves onto the free pole 7 of the yoke 3, the actuating element 4 transmits a tensile force onto the changeover contact 6. In this respect, the tensile force is transmitted via a projecting region 8 of the changeover contact 6 which engages in the opening 1 1 in the actuating element 4. The tensile force of the armature 5 overcomes the spring force of the changeover contact 6 and results in the closing of the circuit between the changeover contact 6 and the make contact 2.

When the coil current 12 is disconnected, the changeover contact 6 is moved by spring force onto the break contact 1. This spring force is transmitted by means of the actuating element 4 onto the armature 5 which resumes the position shown in Figs. 1 and 2.

Fig. 3 shows components of the relay again selected from Figs. 1 and 2. A break contact 1 and a make contact 2 with an interposed changeover contact 6 are shown in the foreground of the illustration. Behind these are shown parts of the magnet system, namely the yoke 3 and the armature 5. In Fig. 3, the actuating element 4 has been removed for the sake of clarity.

The armature 5 comprises two projecting elements 16 which are intended to engage in the openings 14 in the actuating element 4. Furthermore, the noses 17, together with the elements 16, form a recess 18. The purpose of the recess 18 is to lock with the locking elements 15 of the actuating element 4. In this way, the actuating element 4 is reliably connected to the armature 5. At the same time, the armature 5 can be produced in a cost-effective manner, for example as a stamping.

The changeover contact 6 comprises two projecting elements 8 and 9. The purpose of the element 8 is to cooperate with the opening 11 in the actuating element 4. The nose 9 engages in the opening 10 in the actuating element 4.

The nose 8 has a folded-over sheet forming a stop face which runs in a different plane compared to the stop face formed by the nose 9. This means that tensile forces can be transmitted in an almost clearance- free manner from the armature 5 via the actuating element 4 onto the changeover contact 6.

When the changeover contact 6 rests on the break contact 1 and the armature 5 has assumed the position shown in Fig. 2, the stop face 9 moves freely in the opening 10 in the actuating element 4. Likewise, the stop face 9 does not engage with any periphery of the opening 10 when the changeover contact 6 rests on the make contact 2 and the armature 5 is attracted by the free pole 7 of the yoke 6.

However, the opening 10 is dimensioned such that the periphery, facing the armature 5, of the opening 10 comes into engagement with the side, facing the armature 5, of the stop face 9 if the changeover contact 6 rests against the make contact 2 and the armature 5 has assumed the position shown in Fig. 2, i.e. the coil 12 has not been energised. In this position, the actuating element 4 is able to exert a compressive force onto the stop face 9 of the changeover contact 6 via the armature-side periphery of the opening 10 and is thus able to detach the changeover contact 6 from the make contact 2.

Fig. 4 shows a plan view of the magnetic coil 12 and the yoke 3 arranged therein. Fig. 4 also shows the actuating element 4. Said actuating element 4 is locked on the armature 5 by means of the locking elements 15. Also shown are the openings 10 and 1 1 in the actuating element 4 and the relative position thereof with respect to the changeover contact 6 with the stop faces 8 and 9. In Fig. 4, the changeover contact 6 is shown in a sectional view. Furthermore, Fig. 4 shows a break contact 1 and a make contact 2. In this Figure, the changeover contact 6 rests against the make contact 2. The stroke of the armature 5 in the embodiment according to Fig. 4 is calculated such that after resting against the make contact 2, the changeover contact 6 is deflected out further in the direction of the magnet system 3, 12. This additional deflection is also termed an over-stroke. As can be seen from Fig. 4, the effect of the over- stroke is that the changeover contact 6 is moved into a curved or pre-stressed position. In this respect, the curvature is shown on an exaggerated scale in Fig. 4. In an embodiment of the invention, the curvature can amount to from 0.1 to 0.6 mm.

The effect of the over-stroke is that even after a plurality of switching cycles which may have produced a burning of the contact elements 2 and 6, a reliable contact closing is possible. Furthermore, the over-stroke generates a spring force which is opposed to the magnetic force and acts on the actuating element 4 and on the armature 5. . To produce the over-stroke, the nose 8 of the contact element 6 is in engagement with the surface, opposite the magnet system 3, 12, of the opening 11 in the actuating element 4. In this respect, the opening 10 is dimensioned such that the nose 9 on the changeover contact 6 is not in engagement with the actuating element 4.

Fig. 5 shows the situation after the make contact 2 has been opened or after the coil current through the exciting coil 12 has been disconnected. The changeover contact 6 is positioned on the break contact 1 due to the spring force of said changeover contact 6. An insulating air gap is formed between the changeover contact 6 and the make contact 2.

The armature 5 and the actuating element 4 follow the movement of the contact element 6. As a result, the nose 8 on the changeover contact 6 still engages on the actuating element 4 with the face, opposite the magnet system 3, 12, of the recess 11. The stop face 9 of the changeover contact 6 is still freely movable in the recess 10 in the actuating element 4.

Figs. 4 and 5 shows the relay according to the invention in its normal operation, i.e. without the make contact 2 and the changeover contact 6 becoming fused. The changeover contact is moved towards the make contact by the tensile force produced by the magnet system and slides back onto the break contact by spring force when released by the magnet system.

Fig. 6 shows the mode of operation of the relay according to the invention when the make contact 2 and the changeover contact 6 have become fused, which prevents the detachment of the changeover contact 6 from the make contact 2 by spring force. In this case, the actuating element 4 and the armature 5 attached thereto are accelerated by the over-stroke shown in Fig. 4 when the exciting current in the coil 12 is disconnected. In this respect, the acceleration force is transmitted onto the surface of the recess 11 opposite the magnet system 3, 12 via the stop face 8 on the changeover contact 6. The changeover contact 6 cannot follow the accelerated movement of the actuating element 4 due to the fusion. This results in the striking action by the stop face 9 of the changeover contact 6 onto the surface, facing the magnet system 3, 12, of the recess in the actuating element 4. Consequently, the kinetic energy of the actuating element 4 and of the armature 5 attached thereto can be transmitted onto the changeover contact 6 and can be used for forcing apart the fusion between changeover contact 6 and make contact 2.

After the fusion has been detached due to the effect of force of the actuating element 4 on the stop face 9 of the changeover contact 6, the normal position of the components shown in Fig. 5 prevails once more.

Claims

1. Relay comprising a magnet system (3, 12) with which an armature (5) can be brought into a first position or second position, and comprising at least one make contact (2) and at least one changeover contact (6) which can be separated from the make contact (2) by means of spring force, an actuating element (4) being provided which transmits the movement of the armature (5) onto the changeover contact (6) such that in a first position of the armature (5) there is exerted on the changeover contact (6) a tensile force by which the changeover contact (6) can be moved towards the make contact (2) against the spring force, characterised in that the actuating element (4) is arranged to exert a compressive force onto the changeover contact (6) for opening fused contacts (2, 6) in a second position of the armature (5), in that the actuating element (4) is engaged on the changeover contact (6) in a variable spacing such that in the first position of the armature (5), a spacing is formed such that when the armature (5) is moved from the first position into the second position, the actuating element (4) strikes the fused changeover contact (6) shortly before the armature (5) reaches the second position.

2. Relay according to claim 1 , characterised in that the actuating element (4) encompasses the changeover contact (6) to introduce a force which closes the contact.

3. Relay according to either claim 1 or claim 2, characterised in that the magnet system (3, 12) is arranged on the side facing the make contact (2).

4. Relay according to any one of claims 1 to 3, characterised in that the changeover contact (6) can be guided towards a break contact (1) by means of spring force.

5. Relay according to any one of claims 1 to 4, characterised in that the changeover contact (6) comprises a first stop face (8) for introducing the tensile force which closes the contact and a second stop face (9) for introducing the compressive force which opens the contact.

6. Relay according to claim 5, characterised in that the first stop face (8) and the second stop face (9) are located in different planes which run approximately parallel, the first stop face (8) having a greater distance to the make contact (2).

7. Relay according to either claim 5 or claim 6, characterised in that the actuating element (4) has a first recess (11) which is provided for receiving a nose, forming the first stop face (8), on the changeover contact (6) and has a second recess (10) which is provided for receiving a nose, forming the second stop face (9), on the changeover contact (6), the first and second recesses being staggered with respect to one another in a vertical direction to the intended direction of movement.

8. Relay according to any one of claims 1 to 7, characterised in that the changeover contact (6) is configured as a leaf spring.

9. Relay according to claim 8, characterised in that the changeover contact (6) is further deformed in the direction of the make contact (2) in the first position of the armature (5) from a position touching the make contact (2).

10. Relay according to either claim 8 or claim 9, characterised in that the armature (5) and/or the actuating element (4) are arranged to be accelerated by a spring force produced by the changeover contact (6).