ELECTROMAGNETIC ACTUATING DEVICE FOR A VARIABLE VALVE DRIVE

Abstract

An electromagnetic actuating device (8) is for a variable valve drive, in particular electromagnetic switching valve lever systems. The electromagnetic actuating device comprises a base plate (3), a housing which is secured to the base plate (3) and a coil. The housing is designed as a bracket housing (12) and can form part of the magnetic circuit.

Claims

1: An electromagnetic actuating device comprising: a base plate; a housing which is secured to the base plate; and a coil, the housing being a bracket housing.

2: The electromagnetic actuating device according to claim 1, wherein the coil is secured to the base plate along a longitudinal side thereof.

3: The electromagnetic actuating device according to claim 2, wherein the coil is secured to the base plate by thermal contact rivets or crush ribs.

4: The electromagnetic actuating device according to claim 1, wherein the coil is encapsulated by a plastic overmolding.

5: The electromagnetic actuating device according to claim 1, wherein the bracket housing at least partially encompasses the coil.

6: The electromagnetic actuating device according to claim 1, wherein the bracket housing is a bracket that is open on one side and conducts a magnetic flux in conjunction with the base plate.

7: The electromagnetic actuating device according to claim 1, further comprising an armature guide sleeve encompassed by the coil, and an armature in the armature guide sleeve.

8: The electromagnetic actuating device according to claim 7, wherein a pole core is formed in one piece with the armature guide sleeve, wherein an actuating pin engages through an opening in the pole core.

9: The electromagnetic actuating device according to claim 8, wherein a closure disk on a side of the armature guide sleeve opposite the pole core forms an press fit with the armature guide sleeve.

10: The electromagnetic actuating device according to claim 8, wherein the armature guide sleeve is materially bonded to the bracket housing in an area of the pole core.

11: A method of constructing an electromagnetic actuating device comprising: securing a bracket housing to a base plate; and inserting a coil into the bracket housing.

12: The method as recited in claim 11, wherein the bracket housing includes two end faces and a web connecting the two end faces, the coil being inserted axially between the two end faces.

13: The method as recited in claim 12, further comprising pressing a pole core through one of the two end faces, the coil surrounding the pole core.

14: The method as recited in claim 13, further comprising providing an actuating pin protruding through the pole core.

15: The method as recited in claim 14, further comprising connecting the pole core to an armature guide sleeve to form a cartridge receiving an armature connected to the actuating pin.

16: An electromagnetic actuating device comprising: a base plate; a bracket housing connected to the base plate; a coil held inside the bracket housing, the bracket housing including two end faces and a web connecting the two end faces, the coil being inserted axially between the two end faces.

17: The electromagnetic actuating device as recited in claim 16, further comprising a switching cartridge extending through a first of the two end faces and an armature received in the switching cartridge.

18: The electromagnetic actuating device as recited in claim 17, further comprising a yoke formed as a tube extending through a second of the two end faces.

19: An electromechanical switching valve lever system comprising: the electromagnetic actuating device as recited in claim 16; and a switching strip arranged on the base plate and in operative connection therewith, the switching strip being switchable by the electromagnetic actuating device.

20: The electromechanical switching valve lever system as recited in claim 19 wherein the electromagnetic actuating device is configured for being positioned on top of a cylinder head.

Description

BRIEF SUMMARY OF THE DRAWINGS

[0018] An exemplary embodiment explains the present disclosure on the basis of the following figures:

[0019] FIG. 1 shows the basic structure of an electromechanical switching valve lever system;

[0020] FIG. 2 shows an electromagnetic actuating device;

[0021] FIG. 3 shows a sectional representation of the electromagnetic actuating device from FIG. 2;

[0022] FIG. 4 shows the magnetic circuit along the bracket housing and base plate;

[0023] FIG. 5a shows the securing of the electromagnetic actuating unit;

[0024] FIG. 5b shows alternative securing of the coil;

[0025] FIG. 6 shows a switching cartridge.

DETAILED DESCRIPTION

[0026] FIG. 1 shows the basic structure of an electromechanical switching valve lever system 1 as it is known, for example, from DE 10 2017 101 792 A1. A switching strip 2 is arranged on a base plate 3 and is in operative connection therewith. The mechanism has an angle 4 mounted on the base plate 3, the end of which is connected to the switching strip 2. The switching strip 2 is connected to two connecting elements 5 and is displaceable so that the switching pins 6 of two adjacent valve levers 7 can be actuated. The switching strip 2 is switched by an electromagnetic actuating device 8 designed as a linear actuator.

[0027] This has the following advantages: On the one hand, the electromagnetic actuating device 8 does not result in an extension of the cylinder head 9 in the case of an installation associated with the modular structural unit. This means that the installation environment can be adopted without any changes or with only slight adjustments. On the other hand, modules can be used which are equipped with a short structural unit with a switching strip 2, two connecting elements 5 and a base plate 3.

[0028] In the simplest case, these modules can be plugged into the cover of the cylinder head 9 and secured. By reducing the number of controlled valve levers 7, the module can be controlled by an electromagnetic actuating device 8, the structure of which basically corresponds to that of devices that are used, for example, as electromagnets in proportional and switching valves in the area of camshaft adjusters or other variable valve trains. The general requirements are therefore lower than for electromagnetic actuating devices that are used to operate more than two valve levers.

[0029] The mechanism has angle 4 mounted on the base plate 3, the end of which is connected to the switching strip 2. This ensures reliable guidance of the switching strip 2. The electromagnetic actuating device 8 is secured essentially parallel to the camshaft 10 mounted in the cylinder head with the base plate 3, which in turn is arranged essentially parallel to the camshaft 10. An actuating pin 11 of the electromagnetic actuating device is in operative connection with angle 4 arranged on the switching strip 2. Overall, this results in a very compact structural unit.

[0030] FIG. 2 shows the electromagnetic actuating device 8 with base plate 3, a bracket housing 12 fastened to the base plate and with a coil 13. The coil 13 is overmolded with plastic and thus protected against influences from the environment. The plastic overmolding 14 at the same time encases the supply lines and forms a connector 15 for supplying voltage to the coil 13. The unit made up of the coil 13 and connector 15 is secured to the base plate 3.

[0031] The bracket housing 12 is formed from two end faces 16 which are connected to one another on the longitudinal side 26 via a web 17. The end face 16 facing away from the connector 15 has an opening into which a pole core 18 is pressed. An actuating pin 11 protrudes through the pole core 18. Opposite the web 17 is the open side of the bracket housing 12, which is U-shaped as a bracket 27.

[0032] FIG. 3 shows a sectional representation of the electromagnetic actuating device 8 from FIG. 2 with base plate 3, with a unit made up of coil 13 and connector 15 and bracket housing 12. The bracket housing 12 has two end faces 16. The end face 16 facing away from the connector has an opening into which the pole core 18 is pressed. The pole core 18 is connected to an armature guide sleeve 19 (FIG. 6) by means of laser welding and forms a switching cartridge 20 which receives the armature 21 which is connected to the actuating pin 11. The opposite end face 16 has an opening into which the yoke 22 is pressed. The yoke 22 is designed as a tube.

[0033] FIG. 3 illustrates the advantages over electromagnetic actuating devices from the prior art. First, the structure of the yoke can be simplified. The yoke is arranged in the immediate vicinity of the housing, whereby the yoke can be designed as a tube. Second, it is not necessary to design the coil with inserts—there is no need for seals. Seals can also be omitted in the area between the pole core 18 or switching cartridge 20 and the coil 13.

[0034] The advantages of the bracket housing 12 are illustrated in FIG. 4. The base plate 3 is shown with the unit made up of the coil 13 and connector 15 and with the bracket housing 12, through one end face 16 of which the unit made up of the coil 13 and connector 15 engages. The magnetic circuit extends along the bracket housing, but also along the base plate: the open side of the bracket housing 12 is located on the side opposite the web 17. The magnetic circuit is conducted via the base plate 3, which thus enables the housing to be designed in a U-shape.

[0035] FIG. 5a shows the electromagnetic actuating unit with the base plate 3, with the unit made up of the coil 13 and connector 15 and with the bracket housing 12. The underside of the base plate shows how the bracket housing is attached to the base plate. Fastening elements 23 of the bracket housing engage through openings in the base plate, then the connection is made by means of a form fit. The connection is orthogonal to the direction of force and is therefore particularly stable.

[0036] It is also shown how a connection between the unit made up of the coil 13 and connector 15, on the one hand, and the base plate 3, on the other hand, can be implemented. Thermal contact rivets 24 reach through the base plate 3 and establish a connection. Alternatively, the unit made up of the coil 13 and connector 15 can also be secured to the base plate by means of pins (not shown). The unit is held after assembly of the bracket housing 12, which holds the coil 13 in position as shown in FIG. 5b by means of crush ribs 25.

[0037] FIGS. 5a and 5b show the advantages of the unit made up of the coil 13 and connector 15. The unit is secured to the base plate 3 in close proximity to the connector 15, among other things. A securing point 28 is located in close proximity to the connector. In this way, it can be ensured that the connector can be positioned in the correct position relative to the connection environment. In the prior art, existing tolerances of the components between the securing of the coil body and the connector unit add up to a chain of tolerances that does not allow accurate positioning. For example, when the electromagnetic actuating device 8 is arranged in a cylinder head, it must be possible to position the connector 15 in such a way that the connector 15 engages through openings in the cylinder head cover placed on the cylinder head.

[0038] FIG. 6 shows the switching cartridge 20 with the pole core 18, the armature guide sleeve 19, the armature 21, the actuating pin 11, a closure disk 30 and a stop disk 31. The stop disk 31 is made of plastic and prevents the armature 21 from sticking to the bracket housing 12 or to the closure disk 30. The actuating pin 11 is pressed into a receptacle in the armature 21. The unit made up of the armature 21 and actuating pin 11 is then inserted into armature guide sleeve 19 so that the actuating pin engages through an opening 29 of the pole core 18, which is designed in one piece with the armature guide sleeve.

[0039] The closure disk 30 on the side of the armature guide sleeve 19 opposite the pole core 18 forms a press fit with the armature guide sleeve 19. The armature guide sleeve 19, armature 21, actuating pin 11 and closure disk 30 are thus combined to form a switching cartridge 20.

[0040] The armature guide sleeve 19 or the switching cartridge 20 is materially bonded to the bracket housing 12 in the area of the pole core or in the area of the opening 29, which is arranged on the side opposite the connector 15. The armature guide sleeve 19 is thus joined to the coil 13 with almost no force (by providing a clearance fit). The armature guide sleeve 19 is then welded to the bracket housing 12. The welded connection ensures that the armature guide sleeve 19 can be positioned precisely. For positioning, a stop 32 is provided on the side of the bracket housing facing the connector. Damage to the armature guide sleeve 19 during joining can be avoided because only low joining forces are required. The welded joint consists of only individual weld points. This concept ensures that the magnetic resistance in the transition area between the bracket housing 12 and armature guide sleeve 19 is minimal and thus the power density of the actuator is maximized.

LIST OF REFERENCE SIGNS

[0041] 1 Switching valve lever system [0042] 2 Switching strips [0043] 3 Base plate [0044] 4 Angle [0045] 5 Connecting element [0046] 6 Switching pin [0047] 7 Valve lever [0048] 8 Electromagnetic actuating device [0049] 9 Cylinder head [0050] 10 Camshaft [0051] 11 Actuating pin [0052] 12 Bracket housing [0053] 13 Coil [0054] 14 Plastic overmolding [0055] 15 Connector [0056] 16 Rear face [0057] 17 Web [0058] 18 Pole core [0059] 19 Armature guide sleeve [0060] 20 Switching cartridge [0061] 21 Armature [0062] 22 Yoke [0063] 23 Securing elements [0064] 24 Thermal contact rivets [0065] 25 Crush ribs [0066] 26 Longitudinal side [0067] 27 Bracket [0068] 28 Securing point [0069] 29 Opening [0070] 30 Closure disk [0071] 31 Stop disk [0072] 32 Stop