AU746757B2

AU746757B2 - Magnetic system

Info

Publication number: AU746757B2
Application number: AU58514/99A
Authority: AU
Inventors: Olaf Gensch; Jens Oppel
Original assignee: AEG Niederspannungstechnik GmbH and Co KG
Current assignee: AEG Niederspannungstechnik GmbH and Co KG
Priority date: 1998-10-02
Filing date: 1999-08-11
Publication date: 2002-05-02
Anticipated expiration: 2019-08-11
Also published as: TR200001582T1; CN1151524C; ATE354172T1; PL195499B1; WO2000021109A1; EP1036399B1; PL340758A1; ES2283130T3; HU224397B1; DE19845476A1; NO20002809L; HUP0100301A2; AU5851499A; DE19845476B4; HUP0100301A3; BR9907137A; NO317880B1; CN1287677A; DE59914196D1; NO20002809D0

Abstract

The invention relates to a magnetic system for circuit breakers and a method of producing the same. The magnetic system has a sleeve (2) which is housed in a support (1). Said sleeve is enclosed by a coil (3) and has an armature (7) which is slideable in the sleeve. Said armature, in its inoperative position, rests against a dead stop (23) which is formed in the interior of said sleeve and is held therein by a spring-biased plunger (4) which is supported by the armature. Said plunger is impinged by a spring (5) which rests partially on the plunger and partially on an insert (6) in the sleeve. During assembly, the parts are simply inserted into the sleeve in the predetermined order and are fixed in an operative position by inserting the insert or inserting the sleeve into the support, thereby allowing the use of more inexpensive parts and simplifying assembly.

Description

Description The invention relates to a magnetic system for automatic cutouts and to a manufacturing process therefor.

In electrical technology, automatic cutouts are used for the protection of switching circuits against overload, e. g. by short circuits or the like, and serve for automatically interrupting a line, i. e. they break the circuit when such an overload occurs.

For some possible cases of overload, a magnetic system for actuation of the automatic cutout is used. The magnetic system includes a movable armature which, in its inoperative position, partially extends into a coil flown through by the current flowing in the line to be controlled. If the current in the coil exceeds a predetermined releasing current the armature is shifted by the arising magnetic field of the coil and, via a plunger, actuates the automatic cutout.

As the, coil is always flown through by the current to be controlled the actuating unit, that is armature and plunger, must be held in a defined inoperative position in order to ensure a defined response of the automatic cutout and to avoid faulty actuations.

Consequently, the magnetic system must contain a plurality of different mechanical parts so as to ensure this operational reliability. The measure of joining together this plurality of mechanical parts is time-consuming and, consequently, expensive.

The automatic cutouts are manufactured in large quantities since, in the meantime, almost all electric circuits in houses, \factories and the like must be protected by such switches.

P:\WPDOCS\AMDspceci\74K6130.doc-25 Fbrry. 2()02 -2- Consequently, the problem of the invention is to provide a magnetic system for automatic cutouts which can be easily and cheaply manufactured as well as to indicate a process for manufacturing such a magnetic system.

In one broad form, the present invention provides a magnetic system for an automatic cutout, including: a supporting body for receiving a sleeve which is surrounded by a coil connected to said supporting body and which guides a movable armature made of a magnetisable material so as to be shiftable, a plunger which is shiftable by said armature against the force of a spring for actuating the automatic cutout, and an insert which is in engagement with said supporting body and which includes a guide for said plunger as well as a first abutment for said spring, wherein said sleeve has, on its inner side, a stop for said armature, and wherein 15 said plunger has, at its end abutting against said armature, a second abutment for said spring and biases said armature against said stop through the biasing force of said spring, characterised in that said insert includes a projection formed asymmetrically with respect to its axial ends for engagement with said supporting body and said axial ends are i respectively provided with an abutment for said spring, so that two different biases of said .0.

0 20 spring are set by two different assembled positions of said insert in said supporting body.

o e oo 000 ~In a further broad form, the present invention provides a process for manufacturing a magnetic system for an automatic cutout, including the following steps: o• manufacturing of a supporting body, manufacturing of a sleeve provided with a stop on its inner side, manufacturing of an armature and introduction of said armature into said sleeve so as to abut against said stop, manufacturing of a plunger having a first abutment for a spring and introduction of said plunger into said sleeve so as to abut against said armature, manufacturing of a spring and introduction of said spring into said sleeve so as to S abut against said first abutment of said plunger, P:\WPDOCS\AMD\speci\7486130.doc-25 Februa.y, 2002 -2Amanufacturing of a coil and introduction of said sleeve into said coil, manufacturing of a insert including a guide for said plunger, a projection formed asymmetrically with respect to its axial ends for engagement with said supporting body, and an abutment for said spring at each axial end, positioning of said insert such that a predetermined axial end faces said spring, and mounting said insert on said plunger for abutting the respective abutment to said spring for setting the predetermined bias of said spring, insertion of said sleeve and said insert into said supporting body for engaging with same, while biasing said spring, and connecting said coil to said supporting body.

According to the inventive solution, the components of the magnetic system are a :sleeve, an armature, a plunger, a spring, an insert and a supporting body. The parts are designed so that the sleeve can accommodate the members armature, plunger, spring and insert to be inserted with these parts into the supporting body which holds the assembly together.

:In an alternative advantageous embodiment of the invention, in addition to the insert, a solid core is provided which is passed through by the plunger and which is 20 provided between the armature and the insert in order to intensify the magnetic,field of the coil and in order to vary the response behaviour of the magnetic system.

S" Further, the insert can be designed so that it may be pressed into the sleeve so as to hold together a preassembled assembly consisting of the sleeve with armature, plunger, spring and, if necessary, the solid core.

Alternatively, the solid core can additionally take charge of the insert's function if the solid core forms an abutment for the spring so that the spring is biased between the plunger and the solid core.

ingly adapted to the release characteristic of the magnetic system so as to adapt the biasing force of the spring. In this case, always the same spring can be used in order to, nevertheless, obtain different magnetic systems. The adaptation of the insert's length can be effected by an appropriate dimensioning and/or the selection of an insert having the desired length.

The insert can also be designed so that it is provided with an abutment for the spring on each front side, each abutment having a different distance from the insert's supporting point (on the sleeve or on the supporting body). Such an insert can be used by the selection of the fitting position in order to effect the above-mentioned adaptation of length and, consequently, the adaptation of the spring bias.

By the process according to the invention, the magnetic system can be assembled in a simple way by using cheap component parts.

The sleeve which normally has to be manufactured of synthetic material has, at one end, a stop for the armature of a magnetizable material so that the armature can, in a first step of assembly, be simply introduced into the sleeve and is there held by the stop. Then, the plunger which normally likewise has to be made of synthetic material can be introduced into the sleeve and brought into abutment with the armature, the plunger only abutting against a front surface of the armature without being rigidly fastened to same. Now, the spring is shifted over the plunger so that it rests against an abutment on the plunger on the armature's side. By mounting the insert also made of synthetic material by its guide on the plunger the spring comes to rest against an abutment at the insert. If, now, the insert is shifted to its end position the spring is biased and presses the plunger into its inoperative position. The insert may be fastened to the sleeve and/or to the supporting body, wherein the latter may be effected by inserting the sleeve with the above-mentioned parts into the supporting body. In the finished agnetic system, the plunger is biased in its inoperative position and, as a result of the plunger's abutment against the armature, also presses the armature in its inoperative position against the abutment formed in the sleeve.

By the process according to the invention, the subsystem consisting of armature, plunger, spring and insert can be assembled by a simple insertion of these parts into the sleeve without complicated intermediary steps being necessary. In addition, a connection between the armature and the plunger, the spring being arranged therebetween, is not necessary so that simple synthetic parts can be used. If the insert and the sleeve are held by the supporting body it is even possible to manufacture the component parts with relatively large tolerances since no press fit is required to keep the parts together. As, further, the coil which is necessary, anyway, surrounds and holds the sleeve, the coil being rigidly fastened to the supporting body, the entire magnetic system can be joined together to an assembly of cheap component parts with large tolerances and few points of connection.

The following description of preferred embodiments and the remaining subclaims reveal further advantageous developments of the invention.

The invention will in the following be explained more precisely by using preferred embodiments and by referring to the drawings.

Figure 1 shows an enlarged part-sectioned view of a first embodiment of a magnetic system according to the invention; Figure 2 shows an enlarged part-sectioned view of a second embodiment of a magnetic system according to the invention; Figure 3 shows a perspective view of a supporting body; Figure 4 shows a perspective view of a magnetic system according to the invention; and Figure 5 shows a sectional exploded drawing for explaining the process according to the invention.

First of all, as to figure 4 which shows a perspective total view of a magnetic system. Figure 4 shows a supporting body 1 into which a sleeve 2 is inserted. The sleeve 2 is surrounded by a coil 3 one end 32 of which is connected to the supporting body 1. The other end 33 of the coil is connected to a screw terminal 31. In figure 4, reference numeral 7 refers to an armature which is, by the force of a spring, held in its inoperative position where the armature 7 slightly extends beyond the end of the sleeve 2. The supporting body constitutes a yoke for the solenoid which is formed by the coil 3 and the armature 7.

If a current exceeding a predetermined current flows through the coil 3 the armature 7 which is, in its inoperative position, arranged eccentrically with respect to the magnetic field of the coil 3 is, in figure 4, deviated downwards. Thereby, a release mechanism (not shown) is actuated.

In figure 1, a first embodiment of the magnetic system according to the invention is shown. Here, a supporting body 1 having a sleeve 2 held between arms of the supporting body can be clearly seen. The sleeve 2 is surrounded by a coil 3 the one end of which is connected to the supporting body 1 and the other end of which is connected to a screw terminal 31. Within the sleeve 2, an armature 7, a plunger 4, a spring 5 and an insert 6 are arranged. The armature 7 is made of a magnetizable material (iron etc.) and, in its inoperative position, as shown in figure 1, extends only a little into the portion of the sleeve 2 surrounded by the coil 3. If, now, a current of a defined quantity flows through the coil 3 the armature 7 is pulled up and, in figure 1, moved to the right. Thereby, the \rmature 7 shifts the plunger 4 supported under spring bias in -\recess at the armature 7 against the force of the spring When the plunger 4 is shifted its right end as shown in figure 1 further protrudes from the insert 6 and actuates an assigned release mechanism (not shown).

As can be seen in figure 1, the insert 6 has two functions. On the one hand, the insert 6 serves for guiding the plunger 4 passing through the insert 6, on the other hand, the front surface of the insert 6 facing the armature 7 serves as an abutment for the spring 5 which is, consequently, held between the insert 6 and an abutment provided at the armature-side end of the plunger 4. In its inoperative position, the armature 7 abuts against a circumferential shoulder of the sleeve 2 and is held in its inoperative position by the biased plunger abutting against the plunger recess of the armature 7. As further shown in figure 1, the insert 6 has a circumferential projection by which the insert 6 is supported on the supporting body 1 against the force of the spring 5. Alternatively, the insert 6 may also be pressed into the sleeve but it can also be fastened to the supporting body 1 in a different way.

Figure 2 shows a second embodiment of the magnetic system according to the invention. This embodiment has substantially the same structure as the first embodiment, i. e. it comprises a supporting body 1, a sleeve 2, a coil 3, a plunger 4, a spring an insert 6 and an armature 7.

These parts cooperate in the way as explained under figure 1 so that a repetition is not necessary. In addition to the first embodiment, a solid core 8 is arranged in the sleeve 2. This solid core 8 likewise made of a magnetizable material is, as shown in figure 2, arranged opposite to the armature 7 inside of the portion of the sleeve 2 surrounded by the coil 3 and serves for intensifying the magnetic force of attraction acting upon the armature 7 when a current flows through the coil 3.

As clearly shown in figure 2, the solid core 8 has a centric 7ngitudinal bore passed through by the plunger 4 and the spring 5. The bore's diameter is selected so that the plunger 4 and the spring 5 can freely move therein. Besides, the portion of the insert 6 serving as an abutment for the spring 5 can likewise extend into the bore in order to there constitute the abutment for the spring 5. By this embodiment, the first embodiment can be easily modified in that only the solid core 8 is additionally pressed into the sleeve 2. The solid core 8 can also be glued in place or fixed in a different way. The solid core 8 can also be designed such that it also takes charge of the functions of the insert 6 in that it is designed in one piece with a portion corresponding to the insert 6.

Figure 3 shows a perspective view of the supporting body 1 which can be used for the first and second embodiment. As shown in figure 3, the supporting body 1 has an armature-side recess 12 and a plunger-side recess 11. For an easier understanding, the vertical axis of the supporting body 1 according to figure 3 is represented in a way aligned with the vertical axis of the magnetic system in figure 2. As clearly shown in figure 3, the plunger-side recess 11 and the armature-side recess 12 are designed as oblong holes open to one side. Due to this, the preassembled sleeve assembly with the coil placed upon the sleeve can be inserted into the supporting body 1 by lateral introduction. Upon this insertion movement, the circumferential projection of the insert 6 abuts, on the sleeve's side, against the supporting body 1 (figures 1 and while the armature-side end of the sleeve 2 abuts, on the sleeve's side, against the supporting body 1 (figures 1 and In order to improve the support of the sleeve 2 in the supporting body 1 on the armature's side, as shown in the figures 1 and 2, the sleeve 2 can be provided with a supporting arm 24 which grips over to the opposite side of the assigned arm of the supporting body 1. For fastening the sleeve, also other variants of the design of sleeves and supporting bodies can cooperate; for example latches and grooves, gluing, welding etc... Figure 5 shows a sectional view of single parts of the magnetic system in the course of assembly of the magnetic system according to the invention as described in the first embodiment. In figure 5, the parts are put together from the right to the left, i. e. the component parts are inserted into the sleeve 2 from the right in the order as shown. This assembly is preferably effected with the bigger opening of the sleeve to the top so that the parts can be inserted separately and are held by the force of gravity.

As clearly shown in figure 5, the sleeve 2 has a graded bore with the bore portions 21 (smaller diameter) and 22 (larger diameter). At the transition area between these two bore portions 21 and 22, a step is formed constituting a stop 23 for the armature 7.

The armature 7 has a graded outer contour including the portions 71 (smaller diameter) and 72 (larger diameter). Between these portions, a step is formed constituting a contact surface 73. The small-diameter portion 71 of the armature 7 is dimensioned so that it can be introduced, being easily shiftable, into the small-diameter bore portion 21 of the sleeve 2. Likewise, the large-diameter portion 72 of the armature 7 is smaller than the diameter of the large-diameter portion 22 of the sleeve 2 so that the armature 7 can be introduced into the sleeve 2 totally until the contact surface 73 abuts against the stop 23 of the sleeve 2.

After the armature 7 was introduced into the sleeve 2 up to the stop 23 the plunger 4 is inserted into the sleeve together with the spring which is not shown in figure 5 for the sake of clarity. In doing so, the head portion 41 of the plunger arrives at a recess 74 formed on the front side of the armature 7. This recess improves the guidance of the plunger 4 in the sleeve 2 and keeps the spring (not shown) away from the sleeve's wall so that, even in the compressed state of the spring (not shown), no cramping or interlocking can occur. The recess 74 in the armature 7, however, is not absolutely necessary.

Now, the insert 6 with its guide bore 62 is put on the actuating end 42 of the plunger 4 and shifted along the plunger 4, the spring (not shown) being compressed, until the insert 6 has reached a position relative to the sleeve 2 which allows an insertion of the thus finished assembly into the supporting body (see figures 1 and Then, the sleeve is inserted into the supporting body together with the coil (not shown).

When the assembly is inserted into the supporting body the circumferential projection 61 of the insert 6 abuts against the supporting body. The portion 63 of the insert 6 defines the distance between the abutments for the spring (not shown) at the head end 41 of the plunger 4 and at the front-side end of the portion 63 of the insert 6 so that, by determining the length of this portion 63, the spring bias can be selected, while always the same spring is used.

In figure 5, reference numeral 6' shows an alternative design of the insert 6. The shown portion 63' is longer than the corresponding portion 63 of the insert 6. By using this insert, a higher spring bias can be adjusted. Besides, the portion 64' of the insert 6' being arranged opposite to the portion 63' relative to the projection 62' has approximately the same length as the portion 63 of the insert 6. Consequently, two different spring biases can be realized by the same component by simply turning the insert 6'.

Claims

1. A magnetic system for an automatic cutout, including: a supporting body for receiving a sleeve which is surrounded by a coil connected to said supporting body and which guides a movable armature made of a magnetisable material so as to be shiftable, a plunger which is shiftable by said armature against the force of a spring for actuating the automatic cutout, and an insert which is in engagement with said supporting body and which includes a guide for said plunger as well as a first abutment for said spring, wherein said sleeve has, on its inner side, a stop for said armature, and wherein said plunger has, at its end abutting against said armature, a second abutment for said spring and biases said armature against said stop through the biasing force of said spring, characterised in that said insert includes a projection formed asymmetrically with S•respect to its axial ends for engagement with said supporting body and said axial ends are respectively provided with an abutment for said spring, so that two different biases of said Sospring are set by two different assembled positions of said insert in said supporting body.

A magnetic system according to claim 1, characterised by a solid core of a magnetisable material, which is arranged in said sleeve opposite to said armature and is ooo• S 20 spaced apart therefrom, and has a bore passed through by said plunger.

3. A magnetic system according to claim 1 or 2, characterised in that said projection of said insert abuts against said supporting body on the side of the sleeve.

4. A magnetic system according to any one of claims 1 to 3, characterised in that said sleeve has a graded longitudinal bore having a smaller diameter at one end and the diameter step constitutes said stop for said armature. A magnetic system according to claim 4, characterised in that said armature has graded portions of different diameters and a step between two portions of different 7 ~diameters constitutes a contact surface cooperating with said stop.

P:AWPDOCSAMD\speciX7406130.doc-25 Febn-. 2002 -11-

6. A magnetic system according to any one of claims 1 to 5, characterised in that said armature has, at the front surface facing said plunger, a recess for receiving said plunger.

7. A process for manufacturing a magnetic system for an automatic cutout; including the following steps: manufacturing of a supporting body, manufacturing of a sleeve provided with a stop on its inner side, manufacturing of an armature and introduction of said armature into said sleeve so as to abut against said stop, manufacturing of a plunger having a first abutment for a spring and introduction of said plunger into said sleeve so as to abut against said armature, manufacturing of a spring and introduction of said spring into said sleeve so as to .0 o abut against said first abutment of said plunger, manufacturing of a coil and introduction of said sleeve into said coil, manufacturing of a insert including a guide for said plunger, a projection formed asymmetrically with respect to its axial ends for engagement with said supporting body, and an abutment for said spring at each axial end, positioning of said insert such that a predetermined axial end faces said spring, and o• 20 mounting said insert on said plunger for abutting the respective abutment to said spring for setting the predetermined bias of said spring, Sseinsertion of said sleeve and said insert into said supporting body for engaging with same, while biasing said spring, and connecting said coil to said supporting body.

8. A process according to claim 7, including the further step of: manufacturing of a core having a longitudinal bore and pressing of said core into said sleeve in a position opposite to said armature.

9. A magnetic system for an automatic cutout, substantially as herein described with reference to the accompanying drawings. P \\VPDOCS\AMD~zpcci\7X63i.do-25 Febmrnyr, 2002 12 A process for manufacturing a magnetic system for an automatic cutout, substantially as herein described. DATED this 25th day of February, 2002 AEG NIEDERSPANNUNGSTECHNIK GMBH CO. KG By Their Patent Attorneys DAVIES COLLISON CAVE 0*0*