EP2030214A1 - Line circuit breaker and magnet yoke for a line circuit breaker - Google Patents

Abstract

In line circuit breakers with a combined overcurrent/short-circuit current tripping device, tripping should take place in a well defined manner in the case of an overcurrent and in the case of a short-circuit current. For this purpose, gaps (A, B) need to be set precisely. If the housing is made from a cost-effective housing material such as thermosetting plastic it is subject to shrinkage. As a result, the mentioned gaps may change. According to the invention, firstly an armature (24) is mounted in such a way that it changes its rest rotary position in the event of shrinkage of the housing. A magnet yoke (28) as part of the overcurrent/short-circuit current tripping device is mounted and shaped in such a way that the rotation is compensated for precisely, so that the mentioned gaps do not change despite the shrinkage.

Description

description

Circuit breaker and magnetic yoke for a circuit breaker

The invention relates to a circuit breaker according to the preamble of claim 6 and a Magnetj och for a circuit breaker according to the preamble of claim 1.

The circuit breaker has a housing. In the housing, a switching device with a switch on and off and a combined overcurrent short-circuit current release device are arranged. Such a combined overcurrent short-circuit current release device was developed in order to use as few components as possible. It comprises, on the one hand, an armature and, on the other hand, a magnetic yoke, to which a bimetallic element is attached, through which current flows when the switch is switched on. Furthermore, a field line exit plate is arranged on the magnetic yoke, on which magnetic field lines emanating from the bimetallic element when the current flows and which are guided by the magnetic yoke emerge. The bimetallic element is arranged on a first side of the armature. In the undisturbed system it bends at overcurrent and prints on the anchor. The field line exit plate is arranged on an opposite second side of the armature. At a short-circuit current, it magnetically attracts the armature. Thus, both at overcurrent and short-circuit current of the armature is rotated from a rest-rotational position in the same predetermined direction. Upon rotation, it may cause the switch to turn off, for example, via a latch mechanism.

Cost-effective housing materials, such as, for example, thermoplastics (inter alia urea materials), are subject to a housing loss over the course of the device's service life. This is problematic because many components should be stored on the housing. The weakness of the housing then has the consequence that levels of the components to each other. This can have a negative influence on the thermal draw (overcurrent release) and the magnetic draw (short-circuit current draw).

The problem has often been solved by the fact that the entire switching mechanism was stored in metal, so that the Gehauseschwund could have no effect on the draw. These constructions are very expensive.

Alternatively, low-shrinkage or shrinkage-free building compositions, for example melamine compositions, have been used. Also, this solution is more expensive than the use of shrinkage-prone duoplastic compounds.

It is an object of the invention to provide a cost-effective construction in which it is nevertheless ensured that the thermal and magnetic draw takes place reliably.

The object is achieved by a circuit breaker with the features of claim 6 and by a Magnetj och with the features of claim 1.

According to the invention, therefore, a housing is used which is subject to shrinkage and the armature is mounted so that it changes its rest rotational position at Gehauseschwund. The magnetic yoke is mounted so that it also absorbs forces in a Gehauseschwund. It is shaped so that the absorbed forces cause a change in the position of the bimetallic element and the field line exit plate such that the change in the rest rotational position of the armature is counteracted. Preferably, this change is compensated (completely, as far as this is possible during a rotation).

The intrinsically disturbing shrinkage is thus deliberately not decoupled from the armature, but instead the shrinkage is additionally exploited on the side of the magnetic yoke in such a way that the shrinkage effect on the armature and the shrinkage effect on the Magnetj och act exactly opposite.

Preferably, in the circuit breaker according to patent claim 6 an inventive Magnetj och used. Such a magnetic yoke for a circuit breaker has the property that a current-conducting bimetallic element can be fastened to it. It has a basic body which is designed to guide magnetic field lines emanating from a bimetallic element attached to the magnetic yoke when the current flows to a planar field-line exit plate, through the surface normal of which a first direction is defined. On two opposite sides of Magnetj ochs bearing sections are defined with which the Magnetj och can be stored in a housing. The bearing portions further allow the introduction of forces from the housing into the magnet yoke in a second and a third direction (which are generally substantially opposite one another). These directions are substantially perpendicular to the first direction, and by definition at an angle of 75 to 105 ° (preferably 85 ° to 95 °, particularly preferably 90 °) to the first direction.

The Magnetj och invention is characterized in that between one of the two bearing sections and the base body, a flexible element is arranged, which bends upon initiation of acting in the second and third direction forces and thereby allows movement of the field line exit plate in a direction in the Essentially the first direction is the same. By definition, it deviates from this direction by at most 20 ° (preferably by at most 10 °) (this deviation may be arbitrary from the direction of deviation).

In simple terms, it can be said that the magnetic yoke absorbs forces in one dimension and converts them in one movement into a dimension perpendicular thereto. For this purpose, the bendable element is preferably formed rod-shaped and has two rod positions with (compared to the other rod shape) reduced cross-section, which serve as predetermined bending points. By specifying the predetermined bending points, the type of bending is defined particularly clearly, so that the movement of the field line exit plate can be well-defined and the goal can be realized to counteract the change in the rest rotational position of the anchor very accurately.

In a preferred embodiment, the rod-shaped bendable element extends in a straight line at an angle of 35 to 55 ° (preferably 45 °) to the first direction on the one hand and to the second direction on the other hand from a bearing section to the main body. In other words, the rod-shaped bendable element runs "obliquely." As a result, the forces acting in an optimal manner.

Preferably, one of the two bearing portions, between which and the base body, the bendable element is arranged, formed as a T-shaped foot. The foot allows on a first leg the engagement of a screw to define a position of the foot and thus of the Magnetj ochs and on another (opposite) leg an abutment to hold the foot at different positions of the screw.

In a further preferred embodiment, the magnetic yoke is formed as a stamped and bent part. It is thus particularly inexpensive to produce.

Hereinafter, a preferred embodiment of the invention will be described with reference to the drawings, in which

1 schematically illustrates a cross section through a circuit breaker according to the invention,

2 shows a perspective view of the most important

Switching elements of the circuit breaker of Figure 1 illustrates 3 shows the Magnetj och used in the circuit breaker of Figure 1 and Figure 2 in side view,

FIG 4 shows the Magnetj och shown in FIG 3 in the inventive circuit breaker from the side, so as to explain the operation of the Magnetj ochs.

An illustrated in Figure 1, denoted overall by 8 circuit breaker comprises a housing 10 which consists of a material such as thermoset, which is subject to Gehauseschwund. The actual switching device comprises a fixed contact 12 and a pivotable on the fixed contact 12 moving contact 14. The moving contact 14 is moved by means of a handle 16 in the ON position shown in FIG 1, wherein the handle 16 via a bracket 18 and a contact carrier 20 the Moving contact 14 moves.

At the contact carrier 20 engages a pawl 22, which in the ground state, d. H. When the armature 24 is pivoted clockwise, the pawl 22 comes out of engagement, and via the contact carrier 20 causes this lifting of the moving contact 14th from the fixed contact 12 and thus an interruption of the switched-on state.

Such rotation of the armature 24 can be initiated in two different ways. First, a bimetallic element 26 is provided, which is attached to a magnetic yoke 28. The attachment can be seen particularly well in FIG. At rest, the bimetallic element 26 should have a distance A to the armature 24. The bimetal element is traversed by electricity in the on state. When overcurrents, the bimetallic element heats up, bending. In this case, the bimetallic element 26 bends towards the armature 24, overcomes the distance A and ultimately presses on the armature 24 so that it moves in the clockwise direction. It is thus a mechanism for overcurrent extraction. simultaneously can be done with the help of the magnet yoke 28 even with short circuit currents tripping. For this purpose, a field line exit plate 30 is formed on the magnet yoke 28, specifically on the other side of the armature 24 in comparison to the bimetallic element 26, ie, to the left of the armature 24 instead of the bimetallic element 26 to the right of the armature 24. In FIG the basic position, a distance B between the field line exit plate 30 and the armature 24 is defined. In the case of a short-circuit current, the bimetal element 26 flows through a greatly increased current. The magnetic yoke 28 guides the magnetic field lines emanating from the current-carrying bimetallic element 26 to the field line exit plate 30, so that a magnetically attractive force is exerted by the field line exit plate 30 on the armature 24 and this is attracted. Even then he turns clockwise. It is thus a short-circuit release mechanism in addition to the thermal release mechanism. While in the thermal trip mechanism the bimetallic element 26 overcomes the distance A and then presses on the armature 24, the magnet yoke 28 pulls the armature 24 short from the opposite side to overcome the distance B and also causes it to rotate clockwise. The pawl 22 then latches out, and the electrical contact between the moving contact 14 and the fixed contact 12 is released, so the power interrupted.

In both types of triggering, it is important that the respective distance A or B is set precisely, so that the triggering is well-defined. To set the distances A and B is a locking screw 32, which engages in a T-shaped foot 34 of the magnetic yoke 28, more specifically in a leg 36 of the foot 34. The magnetic yoke is supported and held by the opposite leg 38 in a recess 40 in the housing. The position of the screw 32 is fixed. Upon rotation of the screw 32 thus does not change the position of the screw, but that of the magnetic yoke 28, in which the screw 32 engages. Accordingly, the distance A can be reduced and increased and at the same time the distance B are increased or decreased.

The shrinkage of the housing 10 with a longer walking life can now lead to the fact that the distances A and B change, so that the draw is no longer well-defined. The construction as shown in the FIG causes the fading to have opposite effects. The armature 24 is mounted in a bearing 41 on the housing 10. At a loss of the housing 10, the armature rotates clockwise, but not so far that the latch 22 is triggered. In this case, the distance A is increased and the distance B is reduced. Structurally, it is now provided that the magnetic yoke 28 compensates for these changes in the distances A and B exactly.

The magnetic yoke shown as a whole in FIG. 3 has a basic body 42 which has the function of guiding magnetic field lines. The magnetic field lines originating from the bimetallic element 26 are guided. For fastening the bimetal element 26, a fastening element 44 (FIG. 4) is used, for which there is space at an upper section 46 of the magnetic yoke 28. The upper portion 46 functions as a storage section. As shown in FIG. 4, the bearing section 46 engages in a recess 48 in the housing 10. The pedestal 34, which, as mentioned above, engages in the housing in the recess 40, acts as a lying bearing section.

Between the base body 42 and the foot 34 a bendable element 50 is arranged. The bendable element 50 consists of a rod 52 which tapers towards the foot 34 at a location 54 which simultaneously forms the lower leg of the T-shape of the foot 34. Towards the basic body 42, the rod-shaped element 52 also curves at a point 56 which is approximately at the height of the field line exit plate 30. The tapered points 54 and 56 serve as predetermined bending points. The entire rod 52 is substantially at an angle of α on the foot 34 and at an angle ß on a flat normal 58 of the field line exit plate 30th α and ß amount both about 45 °. This is made possible by the fact that the foot 34 is approximately perpendicular to the field line exit plate 30. In fading of the housing now the forces F _Schwindun act on the bearings 40 and 48 (see arrows in FIG 3, also in FIG 4) on the bearing portions 34 and 46. Due to the forces F _Schwindun two directions of force effect are defined approximately perpendicular stand on the surface normal 58. The actual angle slightly deviates from 90 °, but it moves in a range of 75 ° to 105 °.

By forces F _shrinkage now Magnetj och 28 is compressed. At the weakest points, this leads to a bending. These are the points 54 and 56. Thus, the rod-shaped element 52 kinks, in the image to the left, so that the base body 42 moves with the field line exit plate 30 corresponding to the arrow 60. The direction of movement according to the arrow 60 is almost equal to a direction predetermined by the surface normal 58. In any case, the direction of movement 60 does not deviate more than 20 ° from the direction predetermined by the surface normal 58.

The dimensions of the Magnetj ochteile are at the Magnetj och 28 chosen so that the above-mentioned rotational movement of the armature, which is introduced via the bearing 40 of the housing 10 at its loss, is counteracted. As mentioned above, the armature 24 slightly rotates clockwise in case of fading, thereby increasing the distance A and decreasing the distance B. By the simultaneously induced in the shrinkage forces F _shrinkage , the movement corresponding to the case 60 is caused. By the movement 60, the distance B is increased again. The dimensions should be such that the distance B again corresponds to the distance that is defined in the ground state. The movement 60 applies to the entire base body 42 and thus also to the upper part 46. Thus, the bimetallic element 26 also moves in the direction indicated by the arrow 60. Thus, the increase in the distance A is counteracted by the rotation of the armature 24 in the clockwise direction in case of shrinkage of the housing 10. The construction therefore explicitly takes into account that the armature 24 moves due to shrinkage. The Magnetj och 28 is formed so that this does not come to fruition, but that the housing shrinkage simultaneously causes a secondary effect (on the magnetic yoke 28), which counteracts the initial effect (on the armature 24). This counteracting effect is made possible in particular by the provision of the bendable rod-shaped element 52, in particular by the two predetermined bending points 54 and 56.

Claims

claims A magnetic yoke (28) for a circuit breaker (8) on which a current-conducting bimetallic element (26) is arranged and which has a main body (42) which is adapted from the bimetallic element (26) at current flow outgoing magnetic field lines to a field line exit plate (30), through whose surface normal (58) a first direction is defined, and wherein on two opposite sides of the magnetic yoke (28) bearing portions (34,46) are defined with which the magnetic yoke (28) in a Housing (10) is storable, and which the introduction of forces (F _SC hwindung) of the housing (10) in the magnetic yoke (28) in ei ^¬ ner second and a third direction in each case at a predetermined angle to the first direction allow, characterized in that between one of the two bearing portions (34,46) and the base body (42) a deformable element (52) is arranged, which is in the introduction of in the second and third Ric forces acting (F _Sch wmdung) deformed and thereby allows movement of the field line exit plate (30) in a direction (60) which corresponds substantially to the first direction. 2. magnetic yoke (28) according to claim 1, characterized in that the bendable element (52) is rod-shaped and has two points (54, 56) with reduced cross-section, which serve as predetermined bending points. 3. magnetic yoke (28) according to claim 2, characterized in that the rod-shaped bendable element (52) in a straight line at an angle (α, ß) of 35 ° to 55 ° to the first direction on the one hand and the second direction on the other hand from a bearing portion (34 ) extends to the base body (42). 4. Magnetj och according to any one of the preceding claims, characterized in that the one of the two bearing portions between the body and the base (42) the bendable element (52) is arranged as a T-shaped foot (34) is formed on a leg (36) the engagement of a screw (32) for defining a position of the foot (34) and thus of the magnetic yoke (28) and allows on another leg (38) an abutment for the support of the foot (34) at different positions of the screw (32). 5. magnetic yoke (28) according to any one of the preceding claims, characterized in that it is designed as a stamped and bent part. 6. Circuit breaker (8), comprising a housing (10) in which a switching device (12, 14, 16, 18, 20, 22) with an on and off switch (12, 14) and a combined overcurrent short-circuit current Tripping device (24, 26, 28) are arranged, wherein the overcurrent short-circuit current Ausloseeinrichtung on the one hand comprises an armature (24) and on the other hand, a magnetic yoke (28) on which a bimetallic element (26) is fixed, by the current when the switch A field line outlet plate (30) is also arranged on the magnetic yoke (28), on which magnetic field lines emanating from the bimetallic element in current flow and out of the magnetic yoke (28) emerge, wherein the bimetallic element (26) on one side of the armature (24 ) is arranged to print at overcurrent on the armature (24), and wherein the field line exit plate (30) is disposed on an opposite side of the armature (24) to magnetically magnetize the armature at short-circuit current so that both in the event of overcurrent and short-circuit current, the armature (24) is rotated from a rest position in the same predetermined direction, whereby it can cause the switch to turn off during rotation, characterized in that the housing (10 ) is subject to shrinkage and the armature (24) is mounted so that it is at rest in Gehauseschwund Rotary position changed, and that the magnetic yoke (28) is mounted (40, 48) that it (Fschwxndung) also absorbs at a housing fade, and that the magnetic yoke (28) is shaped so that the absorbed forces a change (60 ) effect the position of the bimetallic element (26) and the field line exit plate (30) such that the change in the rest-rotational position of the armature is counteracted and this is preferably compensated. 7. Circuit breaker (8) according to claim 6, characterized in that the magnetic yoke is a magnetic yoke (28) according to one of claims 1 to 5.