EP1897101A1

EP1897101A1 - Method for producing a pole face in a solenoid, armature, yoke, solenoid and electromechanical switchgear

Info

Publication number: EP1897101A1
Application number: EP06763970A
Authority: EP
Inventors: Peter Eckl; Johann Hofrichter
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2005-06-29
Filing date: 2006-06-29
Publication date: 2008-03-12
Also published as: US20080122561A1; CN101185145B; WO2007000474A1; US7861402B2; US8421567B2; CN101185145A; DE102005030376B4; DE102005030376A1; US20100283562A1; JP2009500817A

Abstract

The invention relates to a method for producing a pole face of a metal closing elements (1) of a solenoid (12), especially for electromechanical switchgear. The inventive method is characterized by including a step of machining the surface of a crude stamped part of the closing element (1) to give the pole face (5). The invention also relates to a corresponding armature, yoke, solenoid and switchgear.

Description

Title of the invention

Manufacturing method for a pole face in an Elektromagne ^¬ th, an armature, a yoke, an electromagnet, and an electro-mechanical switching device

Field of the invention

The invention relates to a method for producing a pole face of a metallic closing element of an electric magnet ^¬ advises particular for an electromechanical switching speed. The invention further relates to a yoke and an armature and an electromagnet, in particular for an electromechanical switching device.

Background Art In an electromechanical switching device, such as a contactor or a relay, are for opening and closing ^¬ make the electrical connections electromagnetic actuator Trie ^¬ be needed. A significant part in such actuators is as closing elements an armature and a yoke comprehensive electromagnet. If a current flows through the coils of the electromagnet, the armature is accelerated by the resulting magnetic field to the yoke until the armature and yoke on the pole faces each other lie. If the current is turned off by the coils of the electromagnet, armature and yoke are usually opened by mechanical Rückstellmit ^¬ tel, such as springs and the like. In order to close and open the electrical contacts, moving contact pieces connected to the armature are moved relative to fixed contact pieces in an electromechanical switching device.

Lie in the closed state anchor and yoke to the Polflä ^¬ chen each other, so arise adhesion forces that prevent rapid opening. This adversely affects the switching times of the electromechanical switching device. For this reason, the pole faces of the closing elements of the electromagnet for an electromechanical switching device must have a certain roughness, whereby the mutual Liability of the pole faces is reduced. On the other hand, the pole faces must be flat, since otherwise there is an air gap between the closing elements, which weakens the tributary flow in the magnet system. This leads to a reduction in the holding force and an undesirable increase in the tendency to hum of the switching device.

In order to achieve the desired surface properties of the pole faces, it has heretofore been known to treat the surface of the closing element, which is normally provided as a stamped part, by means of grinding wheels as the pole face. The surface quality can be adjusted by the choice of the force applied to the grinding wheels GRINDER ^¬ terials, such as corundum, and its grain. Disadvantageously, a desirable narrow tolerance range with respect to the surface finish can not be achieved.

Brief description of the invention

It is an object of the invention to provide a method of the type mentioned, with which with respect to the

Surface texture of the pole face with high Reprodu ^¬ zierbarkeit a narrow tolerance range can be achieved. It is another object of the invention to provide an electromagnet, by its use in a switching device, a narrow tolerance range is achieved with respect to the switching time.

The first object is achieved for a method according to the upper ^¬ concept of claim 1 according to the invention in that a surface of a raw stamped part of the closing element to the pole face by a machining method works ^¬ works, eg milled, is.

The other objects can be achieved with the features of the independent claims.

The subordinate claims describe various advantageous embodiments of the various aspects of the invention. The invention is based on the consideration that a narrow tolerance range with respect to the surface finish of the pole face can not be achieved by grinding. This is because grinding wheels always show an inhomogeneous distribution of the abrasive material applied thereon. In addition, the shape and also the size of the individual particles of the applied Schleifmateri ^¬ as well as for a given grain size to a considerable variability. For this reason, it is not possible to machine a surface to be treated as precisely as desired by grinding, even if the grinding machines operate completely precisely.

In a further step, the invention solves the prejudice in the art that the pole faces of Schließelemen ^¬ te a particular intended for an electromechanical switching device electromagnet must be treated by grinding. The invention recognizes that, in contrast to grinding in a surface removal by milling the described uncertainties do not occur. Unlike grinding wheels cutters have defined cutting, terliegen only to aging or wear un ^¬.

Advantages of the invention

Accordingly, if the surface of a rough stamped part of the closing element is not machined by grinding but by a machining method, for example by means of milling, close tolerances can be achieved with regard to the surface quality. Different Anfor ^¬ demands on the surface finish of the pole faces towards ^¬ clearly roughness or flatness can be alone generated by defined machine settings.

For the surface treatment, conventional milling machines and conventional milling tools can be used that allow ge ^¬ cient high setting with respect to the material to be removed. The invention additionally offers the advantage that a multiplicity of different requirements with respect to the surface condition of pole faces, for example for different variants of the same electromagnet, can be generated solely by setting machine-side parameters. In addition, results from the machining Bear ^¬ processing by milling a relatively low heat on the workpiece to be machined. Both wet processing and dry processing are possible.

The method described is not limited in terms of its application to special materials or special compositions of the stamped ^¬ parts. In particular, it is for all ferromagnetic materials for the closing elements of

Electromagnet usable. In particular, the described method is also used to treat the surfaces of conventional ^¬ for example electromagnet of switching devices laminated closure elements is used. In this case, a laminated core is used as a raw stamped part, wherein the laminations of the laminated core are packaged transversely to the surface. The individual sheets are riveted together. The stamped sheets are freed by the use of milling of burrs and bumps. At the same time, the material removal results in the pole surface with the desired surface properties.

Advantageously, the milling of the surface with the input variables feed speed and speed of the milling tool is controlled and / or regulated. The rotational speed of milling tool ^¬ in connection with the feed speed steu ^¬ ert the feed and thus the material removal per tooth or cutting edge of the milling tool. This allows the desired roughness and the desired flatness of the pole surface to be set.

The second object with regard to an electromagnet is achieved according to the invention in that it has a metallic has sches closing element, the pole face is made according to the ^¬ be described method.

Since the surface texture of a pole surface prepared according to the method has a narrow beschriebe- NEN Toleranzbe ^¬ rich, also has a switching device in which such an electromagnet is used, in terms of its switching time a low tolerance width.

List of drawings

Embodiments of the invention will be explained in the examples illustrated in FIGS. Showing:

FIG. 1 schematically shows the milling treatment of the surface of a closing element of an electromagnet designed as a laminated core;

FIG. 2 schematically shows an electromagnet for an electromechanical switching device;

Figure 3 pole face of an anchor;

Figure 4 pole face of a yoke;

FIG. 5 shows a processing station in the production line;

FIG. 6 shows a lifting device in the processing station; and

Figure 7-9 possible relative movement between the work piece carrier ^¬ and the cutters in the milling station.

The same reference numerals refer to similar struc ^¬ tural elements in all figures. Detailed Description Example 1:

It was milled with a commercial milling machine in several series of experiments, the surface of a laminated yoke of an electromagnet for a contactor to the pole face.

The milling cutter used was a standard cutter with three cutters designed as turning inserts. It was mm at a fixed depth of cut of 0.055 and an average width of 25 mm above the table feed at a constant rotational speed of the milling tool of 1492 revolutions varies To ^¬ mm per minute, the feed per tooth from .02 to .125.

Example 2:

In a further series of experiments was for the same closing element with the same machine and the same Fräswerk ^¬ stuff as in Example 1 at a fixed speed of Fräs ^¬ tool of 1910 revolutions per minute and a cutting depth of 0.04 mm and the same cutting width of 25 mm via the table feed the feed per tooth in the same way va ^¬ riiert.

Example 3: In a further series of experiments, the pole faces of a laminated armature were produced as a closing element of an electromagnet for a contactor by milling. The same milling machine and the same milling tool as in Step Example 1 and used ^¬ len. 2 With a fixed cutting depth of 0.08 mm, a cutting width of 25 mm and a speed of the milling tool of 1492 revolutions per minute, the feed per tooth was again varied between 0.02 and 0.125 mm via the table feed.

Result :

In each case, the achievement of the desired values for evenness, roughness and load-bearing ratio was checked in each case. For this, for every milled surface, the over all average flatness, according to DIN 4768 an average roughness and the carrying percentage determined. The average flatness designated ^¬ net while the mean deviation of the surface from the given or before ^¬ desired shape. The average roughness measures the average distance of a measurement point on a top surface ^¬ to the average surface level, that is the arithmetic mean of deviation. The carrying percentage is defined as the proportion of the area lying between recesses on the total area and was determined at a penetration depth of 5 μm.

As a result, it was found out that the respective desired parameters of the surface with regard to roughness, flatness and load-bearing ratio can be defined and reproducibly produced by milling within a narrow tolerance window.

1 shows schematically a laminated closure element 1 for an electromechanical switching device. The closing element 1, for example, the armature of the electromagnet, is composed of packetized sheets 3. The pole face 5, against which the sheets 3 are oriented transversely, is cut by means of a milling cutter 7, e.g. a milling tool, removed. At the same time, the milling cutter is moved in predetermined paths with respect to the marked directions X and Y via the contact surface 5. For removing punching edges and unevennesses, the milling cutter 7 has cutting edges 10 for this purpose. The cutting edges 10 can be designed in particular as exchangeable turning plates.

FIG. 2 schematically shows an electromagnet 12 for an electromechanical switching device. Anchor 14 and yoke 15 of the electromagnet 12 are laminated and each have a central portion 17 and 18 and two outer pole legs 20 and 22, respectively. In the spaces 23 are - not shown - coils used. The pole faces 24 are milled. 3 shows an anchor 14, which has been compiled from ge 32 with rivets ^¬ riveted metal sheets. The outer pole faces 24, ie the end faces of the pole legs 22 of the armature 14, are milled according to the invention. Also, the pole face 31 of the middle pole leg 18 can be milled.

FIG. 4 shows a yoke 15, which has also been assembled from rivets 32 riveted sheets. The outer pole ^¬ surfaces 24, that is, the end faces of the pole leg 20 of the yoke 15, are milled according to the invention. Since the average Polschen ^¬ angle 17 of the yoke 15 as the outer pole ^¬ leg is generally shorter 20, the pole face is preferably of the mitt ^¬ sized pole piece 17 is not milled 41st However, the pole face 41 can also be milled if the middle pole leg 17 is not shorter or if a size-matching milling cutter 7 is present.

Preferably, an electromagnet is implemented with an armature 14 and a yoke 15 of the type mentioned above. The coil is then inserted around the middle pole leg 18 of the armature 14.

When using the electromagnet in an electromechanical switching device, in particular in a contactor, the armature 14 and / or the yoke 15 are also oiled. As a result of the impact-related leakage of the oil present between the individual sheets, an improved damping is achieved when the armature 14 bounces against the yoke 15 when the electromagnetic drive is repeatedly closed.

FIG. 5 shows a processing station 525, 535, 545 in the production line 510. The processing station 525, 535, 545 is designed to implement the method according to the invention.

Stamped parts 520, which may preferably be both anchors 14 and yokes 15, are conveyed in rows on the conveyor belt. In Figure 5, four rows, for example, transported 520 ^¬ next to each other. The rows 520 of stamped parts coming from the production line 510 are laid on a rotatable conveyor table 526 in the loading station 525 by a first robot 530, preferably in rows. The robot 530 also causes the unloading of the conveyor table to the milling station 535.

The milling station 535 preferably receives the stamped parts to be processed in rows. In the figure 5, the milling station with two workpiece holders 536A, 536B shown which allows a conti nuous ^¬ handling of the stamped parts. Other ^{configurations} are also possible.

In the cutting station 535, the milling of the pole face is performed by a relative movement between one of the workpiece carriers 536A and the milling cutter 7.

Another robot 540 removes the milled stampings from a workpiece carrier 536A from the milling station 535 and passes them to the unloading station 545, preferably in rows on the rotatable conveyor table 526, as soon as the stamped parts placed on the workpiece carrier 536A are milled. Simultaneously, milling is performed on the other workpiece carrier 536B, and the first robot 530 replenishes the first workpiece carrier 536A.

The robot 540 restores the milled stampings on the rotating conveyor table 526 to the treadmill 510 via the loading station 555.

6 shows a lifting device in the working ^¬ station 535, with which the stamping parts are lifted before milling. The easiest way is the lifting device in the workpiece carrier 536A, 536B, but other constructions are conceivable.

The anchors 14 or the yokes 15 are, preferably in rows, by movement of a lifting device, such as a Pro raised bar 630. The profiled bar 630 rises by an anchoring M mounted legs 631, 632 to mill the ^¬ the workpieces in such a way between the legs 632, 632 and side walls 610 pinch that the pole faces 24, 31 and 41, slightly above the upper edge of the side walls 610 can be raised. The stops A in the side walls 610 and in the legs 631, 632 are preferably designed such that they clamp the riveted punched parts around the rivets 32 or next to the rivets 32, but that no or only a minimum force and moment action on the rivets 32 Doomed? ^¬ is gently, avoid to deformations of the pole legs better ver ^¬.

FIGS. 7 to 9 show possible relative movements between the workpiece carrier 536 A, 536 B and the milling head 7 in the milling station 535.

Preferably, as shown in FIG. 7, a pole face of a punching element is milled by a progressive movement. In the returning movement then becomes another

Milled pole face. In other words, the milling is in ei ^¬ ne alternating direction, preferably back and forth leads Runaway ^¬.

When the stamping elements are arranged in rows and the rows 520 are adjacent to one another, a relative milling movement is possible, as shown in FIG. The number of rows can be changed as desired, the example in Figure 7 shows four rows 520, each with four stamped parts. The number of stamped parts can be changed at will ^¬ who.

If the stamped parts are anchors 14, all three Polflä ^¬ Chen 24, 41, 24 are milled. According to the invention, at least the pole faces 24 of the outer pole limbs 20, 22 are milled. If the stamped parts are yokes 15, either all or only the outer pole faces 24 can be milled, depending on how large the yoke 15 is. With a relatively small yoke 15, it may happen that the middle pole face 41 can not be milled. This is particularly the case when the cutter 7 is greater than the distance between the Polflä ^¬ chen 24 of the yoke 15, because preferably the middle pole leg 17 is slightly shorter than the outer pole leg 20. The FIG 8 shows the consequent milling movement.

It is also possible, particularly with slightly larger share punching ^¬ that a pole face 24, 31 and 41, with only one cutting movement can not be milled. Then several returning ^{¬ are} necessary, as shown for example in Figure 9. The number of milling movements per pole face can therefore be 1, 2, 3, 4 or more.

In all the illustrations in Figures 7 to 9, the milling is perpendicular to the metal sheets 3 performed each stamped part, data with the riveted sheet packs little deformed possible ^¬ the.

Although the invention has been previously described with milling as a machining method for machining the pole faces, it can not be ruled out that, instead or in addition, another cutting machining method is used, such as planing or turning. However, since the cutting inserts of a milling cutter are completely uncomplicated and inexpensive to renew, milling is preferred here.

Claims

claims

1. A method for producing a pole face of a metallic closing element (1) of an electromagnet (12), in particular for an electromechanical switching device, as ^¬ characterized in that a surface of a raw stamped part of the closing element (1) to the pole face (5) with a machined Procedure is processed.

2. The method according to claim 1, characterized in that a laminated core is used as a raw stamped part, wherein the sheets (3) of the laminated core are etched transversely to the surface pa ^¬ .

3. The method according to claim 1 or 2, wherein the sheets (3) with rivets (32) are fastened to each other.

4. The method of claim 3, wherein the method includes a step of lifting the stamped part before machining with the machining method.

5. The method of claim 4, wherein the stamped part is raised around the rivets or next to the rivets before it is machined by the machining method.

A method according to claim 5, wherein the lifting of the stamped part is carried out by means of a lifting device (630), which is preferably designed to hold the stamped part close to the working plane of the machining method, e.g. close to the milling plane, to clamp.

7. The method of claim 6, wherein the lifting device

(630) for lifting a row (520) of stamped parts.

8. The method according to any one of the preceding claims, characterized in that the cutting process is milling.

9. The method according to claim 8, characterized in that the milling of the surface with the input variables feed speed and speed of the milling tool is controlled and / or controlled.

10. The method of claim 8 or 9, wherein the milling is performed perpendicular to the sheets (3).

11. The method of claim 8, 9, or 10, wherein the milling in an alternating direction, preferably back and forth, is performed.

12. An armature (14) for an electromagnet (12), in particular for an electromagnet for an electromechanical

Switching device, characterized in that at least one pole face (24; 31) of the armature is produced according to a method according to one of claims 1 to 11.

13. An anchor (14) according to claim 12, characterized in that the pole face (24) of the two pole legs (22) and optionally also the pole face (31) of the middle pole leg (32) of the armature (14) according to a method according to of claims 1 to 11 is produced.

14. A metallic yoke (15) for an electromagnet (12), particularly for an electric magnet for a elektrome ^¬ chanisches switching device, characterized in that min ^¬ least one pole face (24; 41) of the yoke egg according to (15) nem method according to one of claims 1 to 11 Herge ^¬ is.

15. A metallic yoke (15) according to claim 14, wherein the pole face (24) of the two pole legs (20) is made according to a method according to one of claims 1 to 11.

16. electromagnet (12), in particular for an electromechanical switching device, i) with a metallic closing element (1) whose

Pole face (5; 24; 31; 41) is made according to a method according to any one of claims 1 to 11; ii) with an anchor (14) according to claim 12 or 13; or iii) with a yoke (15) according to claim 14 or 15.

17. An electromechanical switching device, in particular a contactor or relay, characterized in that i) the pole face of a metallic closing element

(1) an electromagnet ^¬ th in the switching device ^¬ (12) by a method according to one of Ansprü ^¬ che 1 to 11 was prepared; ii) an electromagnet in the switching device has an armature (14) according to one of claims 12 or 13 or a yoke (15) according to one of claims 14 or 15; or that iii) the switching device has an electromagnet (12) according to claim 12.