EP2924701A1 - Attachment block for a low voltage switching device - Google Patents

Abstract

The invention relates to an attachment block (30) for a low-voltage switchgear (1), wherein the low-voltage switchgear (1) comprises an electromagnetic drive (11) with a fixed yoke (12) and an armature (14) movable relative to the yoke (12) and a Switching contact (15) whose contacts are closable and openable by a movement of the armature (14) along an axis comprises. The attachment block (30) comprises a means (32) for damping movement, which in a closing operation of the switching contact (15) by a movement of the armature (14) in the direction of the yoke (12) brakes the armature movement as soon as a contact contact of the contacts of the switching contact ( 15) is given.

Description

The invention relates to an attachment block for a low-voltage switchgear comprising an electromagnetic drive with a fixed yoke and a relative to the yoke movable armature and a switch contact whose contacts are closed and opened by a movement of the armature along an axis.

For low-voltage switchgear there is a need to be able to switch more and more power for a given volume of construction. As a result, higher contact forces are necessary to control the thereby increasing switching currents. The switching process must be performed over the entire, predetermined working range of the exciter coil, i. a predetermined voltage, done.

In order to take account of the increased contact forces with greater power, it is necessary to design the electromagnetic drive stronger. This is reflected in a significantly increased turn-on energy and thus in an increased switching noise noticeable. Depending on the use of the low-voltage switchgear, the switching noise can be disturbing.

A reduction of the switching noise is possible for example by a reduction of the turn-on voltage by means of an electronic circuit. The electronic circuit can be switched between a control supply voltage and a coil of the electromagnetic drive. To turn on the low-voltage switchgear only the so-called. Undervoltage, ie the lowest permitted supply voltage, is applied to the coil. Once the contacts of the switch contact are closed, the voltage is increased to ensure the required high contact force. A disadvantage of this procedure is that the switch-on time of the Low-voltage switching device is disadvantageously increased.

It is an object of the present invention to provide a low-voltage switching device with reduced switching noise without adversely affecting the turn-on speed.

This object is achieved by an attachment block according to the features of patent claim 1 and a low-voltage switching device according to the features of claim 12. Advantageous embodiments result from the dependent claims.

According to a first aspect of the invention, an attachment block for a low-voltage switchgear is proposed, wherein the low-voltage switchgear is an electromagnetic drive with a fixed yoke and an armature movable relative to the yoke and a switch contact whose contacts are closable and openable by a movement of the armature along an axis , includes. The attachment block comprises a means for damping motion, which presses the armature movement in a closing operation of the switch contact by a movement of the armature in the direction of the yoke, as soon as a contact contact of the contacts of the switch contact is given.

By the means for damping movement of the closing operation of the electromagnetic drive is delayed. Thus, the switching noise is significantly reduced without negatively affecting the function of the low-voltage switchgear in terms of switching speed.

The means for damping movement is preferably arranged in a separately provided from the low-voltage switchgear attachment block, so that conventional low-voltage switchgear can be improved by the attachment of a corresponding attachment block in terms of noise. As can be seen from the description below will be adjusted by the design of the means for damping motion of the noise level. Furthermore, influencing the frequency spectrum of the switching noise is possible.

The means for damping movement may comprise a damping plate and a number of abutments, wherein the damping plate abuts the number of abutments as soon as the contact contact of the contacts is given. The damping plate and the number of abutment are arranged to each other such that a concern of the damping plate on the number of thrust bearings takes place only when the contact contact of the contacts of the switch contact is given. Due to the properties of the damping plate during the further switch-on process, it is ensured that the closing operation of the electric drive system is delayed in time.

The damping plate may be mechanically coupled or coupled to the armature. This ensures that the damping plate follows the movement of the armature in the direction of the yoke.

The damper plate may be coupled to an axially extending shank which is mechanically connected to a contact carrier of the low voltage switchgear when the attachment block is mechanically connected to the low voltage switchgear and follows the movement of the armature. The shaft of the attachment block thus represents an extension of a likewise present in the form of a shank contact carrier of the low-voltage switchgear. The mechanical connection between the shaft and the contact carrier can be force and / or positive fit. In practice, it can be provided to produce the mechanical connection between these two components by means of a snap connection.

In a further embodiment, the damping plate may be coupled via a Wegausgleichsfeder with the shaft. hereby can be ensured that the damping plate always rests on the number of thrust bearing as soon as the contact contact of the contacts is given.

According to a further embodiment, the damping plate is elastically deformable from the contact contact by the movement of the armature and the system to the number of stationary counter bearings. As a result, the speed is braked by the movable damping plate in the attachment block until the armature and the yoke of the electric drive system meet. Due to the reduced impact energy with the same moving mass then the noise of the low-voltage switching device or the electromagnetic drive is limited to a minimum.

The damping plate may consist of a reversibly deformable, elastic plastic or a metal. Likewise, the number of counter bearings can consist of a plastic or a metal. For reasons of noise, it is preferred if at least one of the two components consists of a plastic in order to avoid or minimize noise when the two components meet.

In a further embodiment, a plane in which respective impact surfaces of the number of abutments are arranged can be variably aligned in the axial direction. The plane is perpendicular to the above-mentioned axis, along which the movable armature moves towards the fixed yoke. By this configuration, a further reduction of the switching noise is possible because the elasticity of the damping plate is adjustable by the position of the number of thrust bearings. For this purpose, the number of thrust bearings can be adjusted, for example in the manner of adjusting screws by a rotation in the axial direction. It is understood that the axial adjustment of the number of abutments is uniform, so that their impact surfaces are always in the common plane, which is perpendicular to the axis of motion, lie.

The axial displacement thus allows influencing the bending elasticity of the damping plate. As a result, the noise level and the frequency spectrum of the switching noise can be influenced. These significantly influence the switching sensation of people in the vicinity of the low-voltage switchgear.

In a further embodiment, the means for damping movement comprise a spring, wherein the spring is first loaded against its spring force, as soon as the contact contact of the contacts is given. The spring may be provided alternatively or in addition to the damping plate described above and the number of abutments in the attachment block. The spring is arranged in the attachment block in such a way that it is not subjected to any counterforce before the contacts are in contact. Thereby, a maximum damping of the closing operation of the electric drive system can be achieved.

The spring may be disposed in the shaft extending in the axial direction or about the shaft, which is mechanically connected to a contact carrier of the low-voltage switchgear in an attachment block mechanically connected to the low-voltage switchgear and follows the movement of the armature. For example, the spring, when it is arranged around the shaft, can be supported on a housing wall adjoining the low-voltage switching device.

According to a second aspect, a low-voltage switching device is proposed, which comprises a base unit with an electromagnetic drive with a fixed yoke and an armature movable relative to the yoke, and a switching contact whose contacts are moved by a movement of the armature along a Axle closable and openable, and comprises a block attachment according to the manner described above.

The attachment block and the base unit can be two separable components. The attachment block can also be an integral part of the basic device.

Fig. 1

eine schematische Querschnittsdarstellung eines erfindungsgemäßen Niederspannungsschaltgeräts, dessen Schaltkontakt geöffnet ist ("Stellung aus"),

Fig. 2

eine schematische Darstellung des Niederspannungsschaltgeräts aus Fig. 1, in dem nach Anlegen einer Steuerspeisespannung eine Kontaktberührung der Kontakte des Schaltkontakts gegeben ist,

Fig. 3

eine schematische Querschnittsdarstellung des Niederspannungsschaltgeräts aus Fig. 1, bei dem der Schaltkontakt durch den elektromagnetischen Antrieb geschlossen ist ("Stellung ein"), und

Fig. 4

ein Geschwindigkeit-Weg-Diagramm, das die Reduzierung der Auftreffgeschwindigkeit des elektromagnetischen Antriebs im Vergleich zu einem herkömmlichen Antrieb beim Einschalten verdeutlicht.

The invention will be explained in more detail below with reference to an embodiment in the drawing. Show it:

Fig. 1

a schematic cross-sectional view of a low-voltage switching device according to the invention, the switching contact is open ("off position"),

Fig. 2

a schematic representation of the low-voltage switchgear Fig. 1 in which contact contact of the contacts of the switching contact is given after application of a control supply voltage,

Fig. 3

a schematic cross-sectional view of the low-voltage switchgear Fig. 1 in which the switching contact is closed by the electromagnetic drive ("position on"), and

Fig. 4

a speed-distance diagram illustrating the reduction of the impact velocity of the electromagnetic drive compared to a conventional drive at power-up.

The Fig. 1 to 3 The low-voltage switchgear 1 comprises a basic unit 10 with the components required for a switching operation and an attachable to the base unit 10 essay block 30. In principle, the functionality described below of the attachment block 30 could also be an integral part of Basic device 10 be. The variant described below In contrast, has the advantage that standardized basic equipment 10 can be subsequently provided with the separate, inventive attachment block 30 in order to achieve an improvement in terms of switching noise.

In a manner known to those skilled in the basic device 10 comprises an electromagnetic drive 11. The electromagnetic drive 11 consists of a fixed yoke 12 with a coil 13 and a relative to the yoke 12 movable armature 14. The armature 14 is along an axis (so-called. Movement axis) movable in the plane of the drawing vertically from top to bottom.

The basic unit 10 further comprises a switching contact 15, which can be switched by a movement of the armature 14 between a position "open" and a position "closed". The switching contact 15 comprises a first and a second fixed contact piece 16, 18 and a movable contact piece 20. The first and the second fixed contact piece 16, 18 and the movable contact piece 20 extend in planes perpendicular to the axis of movement of the armature. The movable contact piece 20 and the armature 14 are arranged on a shaft-shaped contact carrier 23, which extends in the direction of the axis of movement of the armature 14. The fixed contact pieces 16, 18 and the movable contact piece 20 have contact surfaces 17, 19, 21, 22, wherein at a contact contact of the contact surfaces 17, 21 and the contact surfaces 19, 22, a current from the first Festschaltstück 16 via the movable contact piece 20 and second fixed contact 18 can flow. A current flow is possible as soon as a contact contact of the contact surfaces 17, 19, 21, 22 is given.

A spring 24, which is supported on a relative to the contact carrier 23 stationary abutment, presses the movable contact piece 20 when the switch contact 15 is closed against the Festschaltstücke 16, 18th

The attachment block 30, which in the Fig. 1 to Fig. 3 mechanically connected to the base unit 10, preferably releasably, comprises a shaft 31 which can be moved in the direction of the axis of movement of the armature 14 or of the contact carrier 23. The shaft 31 is arranged in the attachment block 30 in such a way that it extends to the contact carrier 23 of the basic device 10 is formed. More precisely, a free end 43 of the shaft 31 adjoins an end 25, remote from the armature 14, of the contact carrier 23. These can be coupled to one another, for example, via a latching or snap connection (not shown).

With the shaft 31, a damping plate 33 is mechanically coupled. The damping plate 33 may be fixedly connected to the shaft 31. The damping plate can also, as in the Fig. 1 to Fig. 3 is shown coupled via a Wegausgleichsfeder 42 with the shaft 31. The Wegausgleichsfeder 42, as shown schematically in the Fig. 1 to Fig. 3 is shown to be arranged inside the shaft 31. It can also be arranged around the shaft 31. The Wegausgleichsfeder 42 is supported on a Nederlager 44 of the shaft 31, which is the free end 43 opposite.

The damping plate 33 forms, together with a number of abutments 35, 38, a means 32 for damping movement. The damping plate 33 is formed from an elastic, reversibly deformable plastic or metal. Likewise, the abutment 35, 38, in particular their impact surfaces 35, 39 made of an elastic plastic or a metal. Is the switching contact 15 in the "open" position ( Fig. 1 ), so respective impact surfaces 36, 39 of the abutment 35, 38 are arranged at a defined distance from the damping plate 33. The impact surfaces 36, 39 lie in a common plane, which extends perpendicular to the axis of movement of the shaft 31, the contact carrier 33 and the armature 14.

In the graphic representation of Fig. 1 to Fig. 3 By way of example, two abutments 35, 38 are shown. The number of counter bearings could also be chosen larger. Likewise, it is possible to provide a single, then approximately annular trained counter bearing. The abutments 35, 38 are arranged in a perpendicular to the axis of movement wall 41 of the attachment block 30. The abutments 35, 38 can be adjusted in the axial direction, so that the distance between the impact surfaces lying in a plane 36, 39 and the damping plate 33 is adjustable. The counter-bearings 35, 38 can this have the manner of a screw on an external thread, which engages in a corresponding internal thread of recesses of the wall 41. By grooves 37, 40 of the abutment 35, 38 can be adjusted by rotation, for example by means of a screwdriver before the connection of the attachment block 30 with the base support 10, the axial distance in the desired manner.

In addition or alternatively to the consisting of the damping plate 33 and the abutments 35, 38 existing means 32 for damping movement, a spring 34 may be provided in the attachment block, which is supported on an abutment 45. The non-bearing 45 may be formed, for example, by a housing wall of the attachment block 30 adjoining the basic device 10.

By means of the movement damping means or means 32, the armature movement is braked by a movement of the armature 14 in the direction of the yoke 12 by excitation of the coil 13 as soon as a contact contact of the contact surfaces 17, 19, 21, 22 of the switching contact 15 given is. Due to the elasticity of the movement damping means or means 32, the firing process of the electromagnetic drive 11 is thus delayed.

The switching noise can be significantly reduced, without affecting the switching speed of the low-voltage switchgear 1 is adversely affected. The reason for this is that, until contact contact of the contact surfaces 17, 19, 21, 22, movement of the armature 14 in the direction of the yoke is not influenced by the movement damping means or means 32. Only with the contact contact or the means 32 for damping movement are active and reduce the speed of the armature 14 in the direction of the yoke 12. This is readily apparent from the schematic representations of Fig. 1 to Fig. 3 seen.

In Fig. 1 is the low-voltage switchgear 1 off, ie, the switch contact 15 is open. As a result, the armature 14 is spaced from the yoke 12, the contact surfaces 17, 19, 21, 22 do not touch and between the impact surfaces 36, 39 of the abutment 35, 38 is given a distance to the damping plate 33. The distance between the impact surfaces 36, 39 and the damping plate 33 corresponds to the distance between the contact surfaces 17 and 21 and 19 and 22 of the contact pieces 16, 18 and 20th

Fig. 2 shows the low-voltage switching device 1 after applying a control supply voltage to the coil 23, through which the armature 14 is attracted by the yoke 12. In this case, before the armature 14 strikes the yoke 12, a contact contact between the surface contacts 17 and 21 and the surface contacts 19 and 22 of the contact pieces 16, 18 and 20 takes place. At the same time, the damping plate 33 adjoins the impact surfaces 36, 39 of the abutments 35, 38. In the in Fig. 2 illustrated situation, the overall system, consisting of the shaft 31, the contact carrier 23 and the armature 14 speed up to a contact contact of the contact surfaces 17, 19, 21, 22 of the contact pieces 16, 18, 20 is present.

The contact carrier spring 24 is not yet compressed at this moment. In contrast, the Wegausgleichsfeder 42 ensures that the damping plate 33 at the impact surfaces 36, 39 of the abutment 35, 38 rests, but without generating a significant force. In the schematic representation of Fig. 2 is the additional existing spring 34, which is an additional or independent means 32 for motion damping, also not yet compressed.

From the contact contact, the speed of the overall system consisting of the shaft 31 is the contact carrier 23 and the armature 14, braked by the movable and elastic damping plate 33 and / or by the spring 24 in the attachment block 30 until the armature 14 and the yoke 12 meet , Due to the reduced impact energy with the same moving mass, the noise is limited to a minimum. In this situation is in Fig. 3 good to see the deflection of the damping plate 33, which results from the support on the thrust bearings 35, 38. At the same time, the spring 34 is compressed to the maximum. Each of the two measures or both measures in combination provide for the reduction of impact energy.

Out Fig. 3 It can also be seen that also the contact spring 24 is compressed. By its support on the abutment 26, this pushes the movable contact piece 20 firmly against the contact pieces 16, 18 to establish a secure contact between the contact surfaces 17, 19, 21, 22 by an increased contact force by the contact spring 24.

The elastic damping plate 33 is matched in terms of its modulus of elasticity to the prevailing forces in the base unit 10. This affects the length, thickness and material of the damping element 33. This allows for a sound-optimized, gentle turn-on.

The exact configuration of the damping element 33 and / or the spring force of the acting as a brake spring 34 can be found by simulations and / or experiments. The Embodiment depends essentially on the type and / or the design of the electromagnetic drive 11.

The bending stress of the damping element 33 must be smaller by a safety factor than the bending limit of the selected material of the damping element 33. After the switching process, the material must return to its original state. Since the modulus of elasticity of the damping element 33 is temperature-dependent and decreases with increasing temperature (the material thus becomes more elastic), this must be taken into account in the design of the material and the dimensioning.

Due to the axial adjustability of the abutment 35, 38 can by adjusting the distance between the impact surfaces 36, 39 and the damping element 33 in the off state according to Fig. 1 the bending elasticity of the damping element 33 are influenced. This makes it possible to influence the noise level and the frequency spectrum of the switching noise. This can then be determined according to the application of the low-voltage switchgear 1.

Fig. 4 shows a velocity-displacement diagram (vs diagram), wherein a first curve K1 is shown by a solid line and a second curve K2 by a dashed line. The curve K1 shows the speed-distance curve of a low-voltage switchgear according to the invention, while the curve K2 represents the speed-path curve of a conventional low-voltage switchgear without the attachment block as described above.

Position A corresponds to the "open" position, as in Fig. 1 is shown. Until reaching the position B at which a contact touch of the contact surfaces of the switching contact as shown in FIG Fig. 2 takes place, the curves K1 and K2 run in unison. At time C, the position is "closed" according to Fig. 3 achieved, with the speed in the position C of a low-voltage switching device according to the invention is considerably smaller than the position C 'in a conventional low-voltage switching device. From position C or C ', the low-voltage switching device is in the closed state, ie current can flow via the switching contacts. In this state, the switching contacts are static, ie the speed is 0.

By the above-described attachment block and the means for damping motion contained therein, the low-voltage switching device undergoes a higher mechanical bias, which is noticeable when switching off by a higher turn-off compared to a conventional low-voltage switchgear. In order to prevent or brake this higher turn-off speed, a limiter device comprising a freewheeling diode system to capture a mutual inductance may be provided. This makes it possible to reduce the turn-off noise by the Ausschaltanschlag to a minimum.

Claims (12)

Attachment block for a low-voltage switchgear (1), wherein the low-voltage switchgear (1) comprises an electromagnetic drive (11) with a fixed yoke (12) and an armature (14) movable relative to the yoke (12) and a switch contact (15) whose contacts by a movement of the armature (14) along an axis closable and openable, wherein the attachment block (30) comprises a means (32) for damping movement, which in a closing operation of the switching contact (15) by a movement of the armature (14) in the direction the yoke (12) brakes the armature movement, as soon as a contact contact of the contacts of the switching contact (15) is given. An attachment block according to claim 1, wherein the motion damping means (32) comprises a damping plate (33) and a plurality of abutments (35, 38), the damping plate (33) abutting the plurality of abutments (35, 38) as soon as possible the contact contact of the contacts is given. Attachment block according to claim 2, wherein the damping plate (33) with the armature (14) is mechanically coupled or coupled. An attachment block according to claim 3, in which the damping plate (33) is coupled to an axially extending shaft (31) which is connected to a contact carrier (23) of the low-voltage switchgear (1) when the attachment block (30) is mechanically connected to the low-voltage switchgear (1). is mechanically connected and follows the movement of the armature (14). An attachment block according to claim 4, wherein the damping plate (32) is coupled to the shaft (31) via a travel compensating spring (38). An attachment block according to any one of claims 2 to 5, wherein the damping plate (32) from the contact contact by the movement of the armature (14) and the system on the number of fixed abutments (35, 38) is elastically deformable. Attachment block according to one of claims 2 to 6, wherein the damping plate (32) and / or the number of counter-bearings (35, 38) made of a reversibly deformable, elastic plastic or metal. Attachment block according to one of claims 2 to 7, wherein a plane in which respective impact surfaces (36, 38) of the number of abutments (35, 38) are arranged, is variably alignable in the axial direction. Attachment block according to one of the preceding claims, wherein the means (32) for damping movement comprises a spring (34), wherein the spring (34) is first loaded against its spring force, as soon as the contact contact of the contacts is given. An attachment block according to claim 9, wherein the spring (34) is disposed in the axially extending shank (31) or around the shank (31) which, when attached to the low voltage switching device (1), is mechanically connected to a contact support (23). of the low-voltage switchgear (1) is mechanically connected and follows the movement of the armature (14). Attachment block according to claim 10, wherein the spring (34) is supported on a housing wall adjoining the low-voltage device (1). Low voltage device (1) comprising - A basic unit (10) having an electromagnetic drive (11) with a fixed yoke (12) and a relative to the yoke (12) movable armature (14) and a switching contact (15) whose contacts by a movement of the Ankers (14) are closable and openable along an axis, and - An attachment block (30) according to one of the preceding claims.

Images