EP1163687B1 - Electromagnet - Google Patents

Description

The invention relates to electromagnets with the features of the preamble of claim 1.

Joches of magnetic circuits for electromagnets are bolted or obtained by beading in the sheets together a positive connection. This is the usual technique z. B. for ignition transformers. Mostly, these yokes also still sprayed with plastic. The problem is the residual stress thin sheets, which act like disc springs and a dense composite in which every sheet is without play in the composite, by a bracing with screws very difficult.

In addition, in a so-called deep magnet, d. H. z. B. a magnet with a pivotable armature and with in Schwenkachsrichtung wide trained anchor and corresponding Jochen, that a high magnetic force occurs. This leads to a certain deflection of the yoke. This one will reinforced by the distortion of the yoke by the external clamping screws. These design the disk pack fan-shaped, d. H. on the opposite side of the screws Side, an expansion takes place, which manifests itself as Jochdurchbiegung. There are different ones Air column in the middle of the package opposite outside. To a small holding current and a corresponding low loss line should allow However, achieved a small and uniform air gap become.

When using the electromagnet, z. B. in an actuator for driving a valve of an internal combustion engine, In addition to high rigidity, this one must be small too Have dimensions so as not to unnecessarily increase the cylinder head enlarge. He also has to be on different valve distances let adjust. Also, the weight needs to be very small his.

The invention is based on the object, a large To achieve stiffness with small deformations, at small Dimensions and small weight. In addition, the magnets must be easily adjustable on the anchor.

This object is solved by the features of claim 1.

The dependent claims 2 to 11 contain embodiments, who continue to support the task solution.

In claims 12 to 26 is an application of the invention described in an actuator in which the invention particularly favorable effect. Here are the actuators Stable on the cylinder head or an actuator carrier or a tub to be attached to the relative to absorb high forces.

The stiffness is predominantly due to the yoke stiffeners achieved, which not only absorb the magnetic forces but with the training of the actuator with swivel anchor and use a torsion spring as well the bearing forces and the support torque of the torsion bar on the bearing plate. Small dimensions are relatively thin Achieved bearing plates, which are also advantageous for the coil terminals described later. critical is the good non-positive and / or positive connection between the bearing plates and the yoke packages, as the Yoke stiffeners through the yoke side plates the forces derive from the bearing plate in these, so that consuming, thick bearing plates are prevented. The stiffness is by appropriate vote of the Jochpakets with the yoke stiffeners and a corresponding design reached the bearing plates.

In claim 29 is a method for inexpensive production of the electromagnet, or of the actuator described.

Reference to the drawings, embodiments of the invention explained.

Fig. 1

den Aufbau eines Aktuators für den Antrieb eines Ventils eines Verbrennungsmotors in Schnittdarstellung, bei dessen Elektromagneten die Erfindung eingesetzt ist;

Fig. 2

den teilweise gezeigten Aktuator in perspektivischer Darstellung;

Fig. 3

eine teilweise alternative Ausbildung.

Fig. 4

einen Aufblick auf die Anker zweier benachbarter Aktuatoren;

Fig. 5

eine der Lagerplatten;

Fig. 6

eine Detail der Fig. 4 und 5.

Show it:

Fig. 1

the structure of an actuator for driving a valve of an internal combustion engine in a sectional view, in the electromagnet, the invention is used;

Fig. 2

the partially shown actuator in perspective view;

Fig. 3

a partially alternative education.

Fig. 4

an overview of the armatures of two adjacent actuators;

Fig. 5

one of the bearing plates;

Fig. 6

a detail of FIGS. 4 and 5.

In Fig. 1 and Fig. 2 is an electromagnetic actuator 1 for the valve actuation of an internal combustion engine partially shown. The actuator 1 has two electromagnets 2 and 3 consisting of bipolar yokes 2a and 3a and each a winding 2b and 3b. The electromagnets 2 and 3 work together with a lever 4, which with an anchor tube 4a is connected. This anchor tube 4a is around a Axis 5 pivotally mounted. In the interior of the anchor tube 4a a torsion spring 6 is arranged in the form of a torsion bar, which is rigidly clamped at one end and with its other end is connected to the anchor tube 4a. The torsion bar 6 generates, for. B. both acting on the lever 4 Spring forces. The lever 4 carries an armature 7, the cooperates with the electromagnets 2 and 3 and the Pivoting movement generated. The right end 4b of the lever 4 acts on a shaft, not shown, of a valve.

FIG. 2 shows that the yoke 2a consists of lamellae 2a ' composed of magnetic material. It is for Improving the clarity of only a part of the disk pack 2a. In practice, the entire room between the bearing plates 8 with fins 2a 'filled.

In the bearing plates 8, the storage of the lever 4 and so that the armature 7 accommodated by means of the bearing tube 4a. The two bearing plates 8 are by two yoke side plates 9 and 10 connected to each other, wherein the Side plates 9 and 10 are welded into the bearing plates 8 are. The lamellae 2a 'have small bulges 2a '', via which they hung in the side plates 8, 9 are. The side plates 9 and 10 can not be executed magnetic material and they can by an insulation 11 of the slats 2a 'electrically be isolated. This isolation can also be achieved by a Air gap happen. The side plate 10 is as a profile formed so that they can surround the winding 2 b. The profile increases the flexural rigidity of the side panel 10 additionally in the transverse direction. The two side plates 9 and 10 are attached to the upper end of the yoke, whose Bulge has little magnetic flux and thus also low Generated eddy currents.

The assembly of the electromagnet 2 goes into the following Way ahead: First, the side plates 9, 10 are only loosely connected to the bearing plates 8. The lamellae 2a ' are hung in the side panels 9, 10. The anchor is brought into the end position shown in FIG. 1 and the slats or the plate pack with the side plates as a stable composite shifted so that the slats on the anchor 7 lie directly or with a predetermined small air gap to the anchor 7 lie. Now that will be Yoke, z. B. pressed by magnetic force on the anchor and In addition, the two bearing plates 8 on the disk pack 2a pressed and then the side plates 9, 10th connected to the bearing plates at 12, z. B. welded, soldered or caulked. Optionally, by traction on the side plates an additional tension be generated.

To connect the disk pack, the lamellae may have intermeshing toothings and / or it may, for example, near the pole, z. B. at 13 welds of the slats 2a 'with each other, and / or an encapsulation of the disk pack may be provided. Preferably, the fins are welded to the side plates, wherein previously the disk set can be compressed with a defined force.
The electromagnet 3 can be assembled in an equivalent manner.

Figs. 1 and 2 show that the entire actuator on common bearing plates 8 is arranged. You can do that Bearing plates 8 but also extend to the right and in These extensions of the bearing plates 8 another Actuator in the same way, but arranged rotated by 180 °, one must pay attention to the lever ends 4b and the valves driven by them towards the Paper level into each other.

Fig. 3 shows an embodiment in which the left Side plate 10 as shown in FIGS. 1 and 2 is formed. On the other hand, the right side plate 19 covers in comparison to the side plate 9 of Figs. 1 and 2 to a much greater extent the side surface of the yoke 2a. This side plate 19 is along its edges 20 at least with a part of Slats 2a 'welded. This side plate can be made of non-magnetic Material consist; she can over the Slats 2a 'except for the welded edges 20 be electrically isolated. This can also be designed be that the side plate inserted into the slats becomes, as shown on the right half of the picture. Again, the slats 2a ', the bulge 2a' ' to be able to hook in the slats. Alternatively The side plate can be magnetically conductive and without Insulation abut the yoke, whereby the magnetic flux supports becomes. At the ends is also this side plate 19 connected to the bearing plates 8.

Fig. 4 shows a section through a double actuator, as indicated above. On the upper half of the picture a laminated anchor 25 is shown. This is connected to a shown anchor tube 21, in which a torsion bar 22 extends. It is also shown the bearing 23 and 23 a of the anchor tube in the bearing plate. This bearing 23 and 23a can be realized by sliding or rolling bearings. On the left side of the torsion bar 22 is connected to the anchor tube 21 and on the right side with a housing-fixed pivot rod receptacle 24, which is in turn connected to a lever 24a as an extension acting approximately in the center of the bearing plate 25 _r with this at S ₁ is welded. This welding allows accurate adjustment of the torsion bar force by the armature is brought into the closed position of the valve shown in Fig. 2 and then the torsion bar lever 24a is rotated until the corresponding force is reached. Subsequently, the welding takes place. It is advantageous to connect a hydraulic clearance compensation element directly to the armature 25 and the required pressure oil, z. B. via a valve actuating lamella 25a of the armature 25 between the armature and valve arranged clearance compensation element (not shown) to supply. For this purpose, an oil connection 26 is necessary, which is preferably connected to a pressure line of a pump of the engine lubricating oil pump. So that the pressure oil does not escape from the bearing 23a, a sealing element 26a is arranged behind this bearing. The pressure oil passes via the anchor tube 21 into the channel 27 in the valve actuating lamella 25a. The valve actuating blade 25a is arranged off-center. The corresponding blade of the adjacent actuator (half of the picture) is designated 25a '. The distance of the fins 25a and 25a 'corresponds to the valve spacing. From this, the advantage of this arrangement can be seen, since it can be adapted to the valve distances in a wide range. The valve operating blades 25 a and 25 a 'are embedded in the armature packet.

In the bearing plates 25 _L and 25 _R , the bearing bushes 28 are welded or soldered. For exact alignment, this is done in a corresponding device. By means of angle pieces, of which in Fig. 6, the angle piece for the bearing plate 25 _{L is} shown, the actuator with screws 29 is connected to the cylinder head 35. The bearing plates are relatively thin (about 1.5 to 2mm thick). The end lamellae are about 3mm thick, the other lamellae about 0.3mm.

The lower half of Fig. 4 shows the corresponding elements of the adjacent actuator. On the lower half of the image on the left part of the anchor packet 25 is cut away and the disk set 30 of a yoke with a thicker end plate 31 is visible. The outer yoke reinforcement is effected by the side plate 32, which is welded to the bearing plate at S ₃ . For internal yoke reinforcement serves the side plate 33. This corresponds to the structure shown in FIGS. 1 and 3. Here, the inner reinforcement protrudes namely the yoke side plate 33 through the bearing plate 25 _L and is welded at S ₂ with this.

Fig. 5 shows a side view of the bearing plate 25 _L. Fig. 4 shows the view in the drawn y-direction. Here, the yoke side plates 32 and 33 are shown in dashed lines and compared to Fig. 1 and 2 dimensioned slightly different and also the implementation of the side plate 33 through a recess in the bearing plate 25 _L with the corresponding welds S ₂ can be seen. The torsion bar receptacle 24 and the lever 24a can be seen here. The parts 24 and 24a corresponding elements of the left adjacent actuator are arranged on the bearing plate 25 _r diagonally opposite. Thus, the same parts can be used. Also, the fastening screw 29 can be seen. By corresponding recesses of the bearing plates 25 _L and 25 _r projecting the coil 34 therethrough. Their connections 34a are thus easily accessible for contacting the connection cable. The Jochlamellenpaket can also be screwed with any additional welding or gluing or other connection options. The screw connections 37 and 37a shown on the left in FIG. 5 bring the advantage of a simple adjustment. It can, for. B. also only the upper magnet are screwed and the lower welded.

It is also conceivable that the thicker Jochendlamellen 31 z. B. for the two underlying magnets in a kind Bridge are connected to allow easier installation and a further stiffening of the bearing plates to reach. Also, the actuator of FIGS. 4 and 5 for better heat dissipation embedded in the cylinder head 35 be as the Fig. 5 shows below, where the installation tolerances the air gap by heat-conductive fillers can be compensated. It is also conceivable, the heat dissipation thereby improving for the upper magnets that a Wärmeleitblech 36 is used, which is the Dissipates heat from the top of the magnets to the cylinder head.

The bearing plates 25L ₁ and _25R have to be at least slightly magnetic in the region of the armature in order to produce only a small shunt. In the adjacent areas, the material can be magnetic. The non-magnetic material, for. B. V2A costs a multiple of the magnetically conductive material. Therefore, it is conceivable to perform a separation at 25 _LT , such that the middle part 25 _{LM is} non-magnetic and the adjacent part above 25 _LO and correspondingly below magnetic.

In order to produce good heat dissipation, the actuator should be mounted flush with the bearing plates 25 _L and 25 _r .

Fig. 5 and Fig. 6 show the attachment of the actuator by means of the fastening screw 29 on the cylinder head 35th As an alternative to the screw 29 may as shown in FIG. 6 a Shaft screw 29a can be used with a hexagon at the upper end. This design has mounting advantages the accessibility when placing on the cylinder head.

Claims (29)

1. Electromagnet (2, 3) with a yoke (2a, 3a) having an electrical winding (2b, 3b) and an armature (7) facing one of the poles of the yoke (2a, 3a), the yoke (2a, 3a) being formed by sheets (2a') and means (8, 9, 10) being provided for holding together the sheet stack (2a),
   characterised in that
   the sheet stack (2a) is arranged between end plates, in particular bearing plates (8), in that these are connected to one another by flexurally stiff plates, in particular yoke side plates (9, 10), extending along the sheet stack (2a), and in that the bearing of the armature (7) is accommodated in the bearing plates (8).
2. Electromagnet according to Claim 1, characterised in that the sheets (2a') have protuberances (2a'') which make it possible to suspend the sheets (2a') between the yoke side plates (9, 10).
3. Electromagnet according to any one of Claims 1 to 2, characterised in that protuberances (2a") are provided in the vicinity of the end of the yoke (2a) on the other side from the poles of the yoke (2a).
4. Electromagnet according to any one of Claims 1 to 3, characterised in that the connection is produced by friction-locking or form-fitting assembly methods (for example welding, soldering, adhesive bonding, caulking or engagement).
5. Electromagnet according to any one of Claims 1 to 4, characterised in that the yoke side plates (9, 10) are made of a nonmagnetic material.
6. Electromagnet according to any one of Claims 1 to 5, characterised in that the yoke side plates (9, 10) are electrically insulated (11) from the sheet stack (2a).
7. Electromagnet according to any one of Claims 1 to 6, characterised in that at least one side plate (10) has a profile.
8. Electromagnet according to any one of Claims 1 to 7, characterised in that neighbouring sheets are connected to one another by serration (for example so-called punch stacking).
9. Electromagnet according to any one of Claims 1 to 8, characterised in that the sheets (2a') are at least partly also connected to one another by welding or soldering (at 13), in particular near the pole.
10. Electromagnet according to any one of Claims 4 to 9, characterised in that the connection of the yoke side plates (9, 10) to the bearing plates (8) is produced by tensioning the sheet stack (2a').
11. Electromagnet according to any one of Claims 1 to 10, characterised by its use as part of an electromagnetic actuator (1), in which the armature (7) is brought into two end positions by magnetic force (2, 3) in conjunction with two oppositely directed spring forces (6), and in which the armature movements into the two end positions are used to operate a valve of a combustion engine (via extension 4b).
12. Electromagnet according to any one of the preceding claims, characterised in that the connection of at least one end of the side plates (9, 10) to the corresponding end plate (8) is carried out by pressing together the sheet stack (2a') and the end plates (8).
13. Electromagnet according to any one of the preceding claims, characterised in that the bearing of the lever (4), and therefore of the armature (7) via its bearing tube (4a), is accommodated in the bearing plates (8).
14. Actuator according to Claims 11 to 13, characterised in that the yoke side plates (9, 10) of two electromagnets are fastened to the bearing plates (8), and in that this arrangement of the actuator constitutes an assembly unit.
15. Actuator according to Claim 14, characterised in that the end sheets (31) of the sheet stack (30) are designed to be thicker compared with the other sheets (factor of 5 to 10) and are connected to the bearing plates (25_r, 25_L), and in that the bearing plates (25_r, 25_L) are themselves designed to be thin (1.5 to 2 mm) relative thereto.
16. Actuator according to any one of Claims 11 to 15, characterised in that the armature (7) is mounted in the bearing plates (8) so that it can tilt, and a torsion spring (5) connected to the armature provides at least part of the spring forces.
17. Actuator according to any one of Claims 11 to 16,
    characterised in that together with another actuator, it forms a unit which has common bearing plates (25_r, 25_L) for the two actuators, with the actuators facing each other (Fig. 4, Fig. 5).
18. Actuator arrangement according to Claim 17, characterised in that the opposing actuators have actuation elements for the valves, fitted off-centre on the armature, and are arranged rotated by 180° with respect to each other (Fig. 4).
19. Actuator arrangement according to Claim 17 or 18, characterised in that the common bearing plates (25_r, 25_L) are fastened on a cylinder head or actuator support.
20. Actuator arrangement according to any one of Claims 17 to 19, characterised in that the bearing play is eliminated during adjustment by pressing in the bearing (4a), preferably in the direction of the magnets (2 and 3).
21. Actuator arrangement according to any one of Claims 18 to 20, characterised in that the two bearing plates (25_r, 25_L) are connected to each other by screws (37, 37a).
22. Actuator arrangement according to Claim 21, characterised in that the yoke side plates (32, 33) are also connected (for example welded, adhesively bonded, soldered) to the bearing plates (25_r, 25_L)..
23. Actuator arrangement according to any one of Claims 18 to 22, characterised in that the bushes (23) for bearing the armatures (25) are fitted into the bearing plates (25_r, 25_L) by friction-locking and/or form-fitting.
24. Actuator arrangement according to Claim 23, characterised in that the bearing bushes (23) are arranged at least approximately on the mid-line of the bearing plates (25_r, 25_L).
25. Actuator arrangement according to any one of Claims 18 to 24, characterised in that for adjustment of the rotary bar, the armature is brought into at least one end position (for example resting on the magnet 2), in that the rotary bar is then prestressed to a particular value by means of the lever (24a), and in that the lever (24a) is subsequently immobilised (welded).
26. Actuator arrangement according to any one of Claims 18 to 25, characterised in that the end sheets (31) of two sheet stacks are at least partly connected to one another by a bridge.
27. Actuator arrangement according to any one of Claims 18 to 26 characterised in that the bearing plates (25_r, 25_L) are formed by a plurality of sub-plates (25_LO, 25_LM), in that one of the sub-plates (25_LM) consists of a substantially nonmagnetic material, and in that this sub-plate (25_LM) is arranged in the vicinity of the armature (25).
28. Actuator according to any one of Claims 18 to 27 characterised in that the bearing plates (25_r, 25_L) are connected, in particular screwed, to an actuator support or the cylinder block (35) by means of an angle-piece.
29. Method for producing an actuator arrangement according to Claims 18 to 27, characterised in that the armature (25) is fitted in the end position near the pole,
    in that the sheet stack is adjusted to a minimum air gap from the armature (25),
    in that the sheet stack is then pressed together, and
    in that the connections between the bearing plates (25_r, 25_L) and the side plates (32, 39) are then produced, preferably simultaneously on both sides.

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