Patent Application
20190304712
The present disclosure concerns an electromagnetic switch.
Electromagnetic switches, which are implemented as relays for example, include as a rule an armature that can be implemented as a rocker armature. A lever can be used for manual actuation of the armature, the said lever changing the position of the armature so that the contact springs coupled to the armature perform a switching movement and the contacts of the relay can be opened or closed.
However, in the event of a fault, for example at higher currents, temporary welding of the contacts can occur. Manual actuation of the lever can lead to damage of the contact springs in the relay in such a case. A solution to this problem is proposed in DE 102012006438 by increasing the contact areas in the relay, thus reducing the probability of welding between the contacts.
The object of the present disclosure is to create a design for avoiding damage in a fault case to an electromagnetic switch of the aforementioned type.
This object is solved by the characteristics of the independent Claim 1, Advantageous examples of the disclosure are subject matter of the figures, of the description and of the dependent claims.
The disclosure is based on the knowledge that the above object can be solved by limiting the forces which can be transferred from a switch to an armature of an electromagnetic switch, for example a relay. This can prevent especially a plastic deformation of components of the electromagnetic switch, of contact springs for example, for welded contacts for example.
According to a first aspect of the disclosure, the object is solved by an electromagnetic switch that has an armature and a slider that is manually slidable for actuating the armature. Furthermore, the disclosure-related electromagnetic switch has a deformable force transfer element that is positioned between the slider and the armature. The slider is pressable with a pressing force against the deformable force transfer element by manual actuation in order to actuate the armature. The slider exerts here forces on the force transfer element, the latter transferring these to the armature. With this, the armature can be actuated manually from outside via the slider. The deformable force transfer element is deformed by the press force on exceeding a press force threshold. This limits the transferable press force from the slider onto the armature.
An alternative to a slider for manual actuation is another actuating element, for example a press switch or a lever, insofar that this is suitable, that can transfer the force applied to the force transfer element by an operator. If the force applied by the operator on the slider exceeds a certain threshold, the force transfer element deforms and, due to its deformation, ensures that the force transferred to the armature by the force transfer element does not exceed the threshold value. The threshold value is so selected that it does not yet produce a plastic deformation of components, contact springs of a relay for example, and so does not lead to permanent damage of the components, if for example contacts of the switch are welded together and the user attempts to separate the contacts manually. The threshold value can for example be so selected that it corresponds to the force that a magnetic system of the electromagnetic switch, also taking an excitation into account, would also exert on the armature.
The limiting of the press force due to deformation of the force transfer element on exceeding the threshold value is invoked. Even low forces can cause a certain deformation of the force transfer element, but do not lead to a limiting of the press force. It is therefore always ensured that the forces transferred by the force transfer element to the armature are at least large enough so that the contacts of the switch can be opened and closed in the fault-free condition of the electromagnetic switch. The press force in the disclosure-related electromagnetic switch can also increase during the deformation of the force transfer element and has then reached its maximum travel when the slider is moved by the operator and then reach the force threshold value, so ensuring that the press force threshold value is not exceeded over the entire travel path of the slider and is independent of the forces exerted on the slider.
An electromagnetic switch configured within the meaning ofthe disclosure is especially characterised by the fact that forces applied by the operator via the slider or another actuating element on the other components of the electromagnetic switch are so limited by design that permanent damage to components, e.g. contact springs of the electromagnetic switch, is effectively prevented.
According to a further advantageous form of the disclosure, a provision is made to connect the deformable force transfer element to the armature. This can take place as materially bonded or frictionally connected. A form-locking engagement between the force transfer element and the armature is also possible. The force transfer element can for example be riveted, screwed, bonded, soldered or welded to the armature. This prevents the force transfer element changing its position relative to the armature and also relative to slider and causing malfunctions or functional failures.
The armature of the electromagnetic switch can be a rocker armature, but also another type of armature, e.g. a hinged armature.
According to a further advantageous form of the disclosure, the deformable force transfer element can be deformed plastically or elastically. Here, the degree of deformability can be influenced on the one hand by the choice of material; but especially on the other hand by the geometric design of the force transfer element. The deformation of the force transfer element in the case of an elastic force transfer element is reversible, even when forces applied over the entire travel path of the slider exceed the press force threshold value. The forces applied by the operator do not then lead to a permanent deformation of the force transfer element. The effected limiting of the applied forces by the force transfer element on the press force threshold value is therefore possible, even with multiple operator errors, in which large forces are exerted on the slider. Damage to the force transfer element does not occur.
If the force transfer element, on the other hand, is plastically deformable, even a one-off manual operation in which the press force threshold value is exceeded leads to a permanent deformation of the force transfer element so that in a repeated manual operation, either a limitation of the press force by the force transfer element on the press force threshold value is not ensured, or with a manual operation, the forces are no longer adequate to open or close the contacts of the electromagnetic switch.
In a further advantageous example, the deformable force transfer element has a deformable tongue. The electromagnetic switch is so designed that the slider can be pressed against the deformable tongue. The deformable tongue can be deformed in order to absorb the press force of the slider when the press force threshold value is exceeded. By deforming the tongue, the force exerted by the slider on the tongue can be so reduced that the tongue exerts a force on the armature that is not greater than the press force threshold value. The tongue can have various designs, for example, it can be triangular are or wave-shaped, wherein the triangle or the wave is preferably pointing from the armature in the direction of the slider. The tongue can have a flank, against which the moving slider can come to rest so that the slider can exert force on the tongue to move the armature via the flank.
In a further advantageous example, the deformable force transfer element comprises a circumferential frame to which the armature is attached. A window is formed in the circumferential frame in this example. The deformable tongue is attached on one side to the circumferential frame and, in deformation of the deformable force transfer element, the tongue can be taken up (at least partly) by the window. In this, tongue and frame can be designed as monoblock parts. The circumferential frame can have a section where the deformable tongue is fixed to the frame by means of which the force transfer element can be attached to the armature. In the plan view of the force transfer element, the tongue can be completely surrounded by the frame in its projection.
In a further advantageous example, the deformable tongue formed by a partial circumferential slit into a material part. In this, the circumferential frame surrounds the partial circumferential slit. The tongue is therefore cut free from the material part by the slit. The tongue can protrude from a plane of the material part, for example in wave shape, triangular shape, or even curved shape, so that the slider can come to a stop in its movement along the tongue in order to transfer these forces. The tongue can for example be made by punching out from a material part wherein the circumferential frame and the partial circumferential slit are also obtained from the punching out. Das punching can be preferably carried out on only one section of the material piece so that the material piece has a further section in which no slit is present and that the tongue and frame are fixed to this further section and the force transfer element can be attached to the armature by means of this further section. After the punching out of the tongue from an initially flat piece of material, the tongue can protrude from the plane of the piece of material after the subsequent deformation, in the form of a triangle or wave as described above, and the circumferential frame can be prestressed by applying forces so that the press force threshold value can be adjusted by the prestressing, amongst other things.
In a further advantageous example, the deformable tongue is in the form of a wave. It is so designed and positioned between the slider and the armature that a wave flank of the deformable tongue is contacted by the slider. As already described above, other geometrical forms, e.g. triangular form or a semicircular form, are possible for the tongue, which allow forces exerted by the operator on the slider to be transferred to the tongue. When the slider is moved by the user, a flank of the slider comes to rest at the deformable tongue and transfers forces to the deformable tongue, the said forces—at least when the press force threshold value is exceeded—then lead to a deformation of the tongue. Because of the tongue's elasticity, a certain deformation can however already occur before the press force threshold value is exceeded.
In an advantageous example of the disclosure, the press force threshold value is dependent on the geometrical form of the tongue. The properties of the tongue depend on its geometric shape. For example, the stiffness of the tongue on the one hand depends on the thickness of the material, but especially also on the design of tongue. Various stiffnesses can be achieved by the use of different designs. The tongue can also be fitted with stiffeners or cutouts to reduce the elasticity of the tongue. i.e. make the tongue stiffer, or increase elasticity of the tongue, i.e. reduce its stiffness, whereby the press force threshold value is reduced.
In a further advantageous example, the deformable force transfer element is so designed that it transfers a press force from the slider to the armature as long as the press force does not exceed the press force threshold value. The armature is actuated for this. A force that exceeds the press force threshold value is only transferred from the slider to the armature at the level of the press force threshold value.
In an especially advantageous example, the electromagnetic switch has an electromechanical contact. One or more electromechanical contacts can be provided here. The electromechanical contact can be freely released in the non-locked contact state, i.e. when the contacts are either not mechanically locked together or especially when not welded together. The electromechanical contact can be released by the armature by exerting a releasing force. The releasing force is exerted on the contact directly by the armature or via intermediate elements, wherein the releasing force is formed by the force transferred via the deformable force transfer element on the armature. The force transferred by the force transfer element is formed from the force applied by the operator on the slider that the slider then applies to the force transfer element. The press force threshold value is greater than the release force so that a deformation of the force transfer element that would lead to a limiting of the press force to the press force threshold value does not do that as the press force is limited to a value that is lower than the release force that is to be applied to release the contact. This ensures that the contacts, if not locked, e.g. not welded, can always be released manually from each other by means of the slider or, in another example, can also be closed. If there are several contacts present, a contact can be opened by the actuation of the slider while another contact is simultaneously closed. This is for example the case when the contacts are positively driven so that the opening of a contact always leads to closing of one of the other contacts and vice versa.
In an especially advantageous example, the deformable force transfer element is so designed that when at least one electromechanical contact is in a locked state, for example is welded due to overcurrent, the electromechanical contact cannot be released by the user actuating the slider. The deformable force transfer element deforms when the force applied exceeds a press force threshold value. The press force threshold value is so selected that a release of locked, especially welded, contacts by the forces exerted on the slider is not possible. This prevents the components of the electromagnetic switch being plastically deformed by the slider forces applied via the force transfer element on the armature, and leading to irreversible deformation of components and so to permanent damage of the electromagnetic switch. For example, this prevents contact springs of the electromagnetic relay being irreversibly bent, so damaging the relay and possibly making it unusable. The deformable force transfer element is so designed that it limits the press force to a press force threshold value so that the press force threshold value is lower than the force that would lead to plastic deformation of components, for example contact springs, of the electromagnetic switch so that the forces transferred to the armature can never lead to a plastic deformation, and so never to damage of electromagnetic switch components.
In an especially advantageous example, the deformable force transfer element is so designed that a break in the slider due to mechanical overloading is prevented. The forces transferred by the deformable force transfer element onto armature are so limited by the design of the deformable force transfer element that they cannot exceed the forces which would result in damage to the slider.
In a further advantageous example, the deformable force transfer element is implemented as a single piece. In the example described above with frame and tongue, frame and tongue for example are manufactured by punching from a single piece of material; in the same way, a section of the force transfer element that can be used to attach the force transfer element to the armature. The tongue and also the frame can be so geometrically designed that a desired press force threshold value can be set. The one-piece force transfer element is preferably formed here from metal, spring steel for example. The force transfer element can for example be implemented as a leaf spring. The press force threshold value can be influenced by the pre-stressing of the force transfer element.
In a further advantageous design, the electromagnetic switch is implemented as a relay. The relay in this has, disclosure-related, a slider, a force transfer element for transferring the forces of the slider to an armature, as well as the armature. The armature is so designed that a movement of the armature leads to opening or closing of one or more contacts. The opening or closing of at least one contact can still occur via further intermediate elements between armature and contact, for example intermediate lever and contact springs. In the implementation of the electromagnetic switch as relay, the press force threshold value is so defined that the forces applied by the force transfer element on the armature and then from that onto further components, e.g. contact springs are not sufficient to plastically deform further components, for example when a user attempts to loosen welded-together contacts by means of the slider, so that damage to the relay from too large forces exerted by the operator can be prevented.
In a further advantageous example, especially when the electromagnetic switch is designed as a relay, the electromagnetic switch has at least two contacts wherein the contacts are positively driven. An opening of a contact therefore leads inevitably to the closing of the other contact. This ensures that a plastic deformation of the components of the electromagnetic switch is prevented by limiting the press force, that the positively driven operation of the contacts is not cancelled by unallowably heavy deformation of components, contact springs for example. This ensures that, because of the positively driven operation, the state of a contact. i.e. open or closed, the state of the other contact that is antivalent to the state of the first contact, can be uniquely determined.
Examples of the present disclosure are described in the following with the help of the accompanying drawings.
In the non-actuated state of the slider 101, the tongue 107 of the deformable force transfer element 105 lies in a recess 111 in the slider 101 so that no forces are applied to the tongue 107 of the force transfer element 105 via slider 101. This also means that no forces are exerted on the armature 113 by the force transfer element 105 when the slider 101 is not actuated. Forces are therefore also not exercised on the contact spring 121 of the normally open contact by the armature in this condition so that the normally open contact 119 is open. A return spring 127 together with a magnetic restoring torque ensure that the armature 113 is always in a position in which the normally closed contact 123 is closed when no further electromagnetic or manual forces are exerted on the armature.
In the example of the electromagnetic switch shown in
The deformable force transfer element 105 in
The armature 113 in the example of
In addition to a manual actuation via the slider 101, the electromagnetic switch 100 in the example of
The manual actuation of the electromagnetic switch 100 as relay example from
In the state shown in
In the slider 101 position shown in
As already described above, the deformable force transfer element 105 in the example shown has a tongue 107 via which the force exerted by the user on the slider 101 is transferred to the deformable force transfer element. The deformable force transfer element 105 also has a frame 109. Such an example of a deformable force transfer element 105 is described below in the explanations of
In the state shown in
For the position of the slider 101 shown in
In the condition shown in
In the condition shown in
The deformable force transfer element 105 is so designed in its geometry and elasticities that the maximum force transferred from slider 101 via the deformable force transfer element 105 to the armature 113 is smaller than the force that would lead to a plastic, i.e. permanent, deformation of the contact spring 125 of the normally closed contact 123. In other words, before a plastic deformation of the contact spring 125 of the normally closed contact 123 occurs, the forces that would be necessary for this are limited by an elastic deformation of the tongue 107 relative to the frame 109 of the deformable force transfer element 105. The deformable force transfer element 105 and especially its frame 109, is itself prestressed in the example shown in
In the example shown in
A tongue 107 is formed on the force transfer element 105, the former being surrounded by a frame 109. Frame 109 and tongue 107 are joined together at the transition in the rear section 405 of the force transfer element 105. The tongue 107 is so formed that it protrudes from the plane spanned by the force transfer element 105. The tongue in the installed condition thus protrudes in the direction of slider 101 so that when the slider 101 moves in the actuation direction 103 due to the slider 101, forces can be exerted on the flank of the tongue 107.
A slit 401 is formed between frame 109 and tongue 107 that enables the movement of the tongue 107 relative to the frame 109. The slit 401 surrounds a window 409 in which the tongue 107 is positioned and in which the tongue 107 can move relative to frame 109 when forces are applied.
The force transfer element 105 is folded in a front section 403, which reduces the window 409 for the movement of the tongue 107 so that the front section 501 of the tongue 107 (see
The deformable force transfer element 105 is internally prestressed, i.e. the section of the force transfer element 105 in which the tongue 107 and the frame 109 are arranged is prestressed or bent up in the direction of the slider, protruding from the plane of the section 405 in which the force transfer element 105 is fixed to the armature in the installed condition. The degree of prestressing here influences the amount of the force transferred from slider 101 to the armature 113 via the tongue 107 and the frame 109.
In the manufacturing step shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2016 109 486.2 | May 2016 | DE | national |
This application is a 371 national phase filing of International Application No. PCT/EP2017/062329, entitled “ELECTROMAGNETIC SWITCH”, filed 23 May 2017, which claims priority to German Patent Application No. 10 2016 109 486.2, entitled “ELEKTROMAGNETISCHER SCHALTER”, filed 24 May 2016.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/062329 | 5/23/2017 | WO | 00 |
