EP2582928B1 - Actuating device for displacing a cam unit - Google Patents

Description

Field of the invention

Actuator device of a sliding cam system, comprising at least one sliding cam and with an engaging pin projecting from a housing, wherein the housing is arranged on a component of a cylinder head or on the cylinder head of an internal combustion engine, and the engagement pin is contactable with at least one groove of the sliding cam system, the at least one Auswurframpe and wherein the engagement pin has a permanent holding magnet inside the housing and is subsequently dominated by a stationary spool core which can be magnetized by an electrical coil, and the engagement pin is spring-loaded in the direction of the sliding cam.

Background of the invention

Such a generic actuator is from the DE 102 40 774 A1 or the DE 10 2007 052252 known. Starting from the retracted inner layer of the engagement pin, an activation of the engagement pin takes place by energizing the coil, whereby a magnetic field is generated which is opposite to the field of the permanent holding magnet and displaces it. The displacement of the field causes a reduced holding force between permanent magnet and spool core, so in that the magnetic field generated by the coil and the force of the spring acting on the engagement pin causes the engagement pin to extend so that it engages in the groove of the sliding cam system and causes displacement of the sliding cam as desired.

The backward movement of the engagement pin into its inner end position is initiated by the ejection ramp, which is to move the engagement pin against the force of the spring so far and with such acceleration of the sliding cam that the engagement pin with energized the coil by the permanent magnet and its magnetic field on the spool core is held.

The problem with this generic embodiment is that depending on the tolerance position of the actuator radially to the sliding cam movement and acceleration of the engagement pin by the ejection ramp is insufficient that this reaches the inner position and is stabilized by the permanent magnet against the force of the spring.

Furthermore, there is the problem that in sliding cam systems with three or more sliding cam at least two engagement pins must be provided. In this case, a small distance of the engagement pins, which is determined by the distance of the gas exchange valves, the distance of the cylinder of the internal combustion engine and the number of sliding cam is required. Due to the short distance described in the prior art design of the actuator is no longer able to move the engagement pin with sufficient speed and force and hold.

Object of the invention

The object of the invention is therefore to improve an actuator with the features described above so that larger tolerances can be absorbed and also a desired lower distance of the engagement pins can be ensured each other.

Summary of the invention

The object of the invention is solved by the features of claim 1.

The actuating device generates an additional force to the force introduced by the ejection ramp, by means of which the engagement pin reliably reaches the inner end position. As a result, the tolerances that occur during installation of the electrically actuated device, without significant impact on the operation of the engagement pin, so that the tolerances do not need to be kept very tight. Furthermore, the dimensions of the built-in housing parts, in particular the permanent holding magnet on the engagement pin can be kept smaller, so that a small distance of the engagement pins to each other can be realized.

In an advantageous embodiment of the invention it is proposed that the engagement pin has at its end facing the sliding cam an opening in which an actuating member is slidably disposed, which is loaded in the direction of the sliding cam by means of a return spring. The position and the paths of the actuator and the force of the spring is so dimensioned that it is compressed, in particular in the area of the ejection ramp, but extended at the end of the ejection ramp and supported on this, so that the return spring of the actuator such a force generated on the engagement pin, that this overcomes the residual stroke and safely reaches its inner end position.

In a further embodiment of the invention it is proposed that the actuating member is formed on the engagement pin as a ball which is installed in a bore of the engagement pin with the associated spring and that the bore is narrowed at its end to a secure hold of the ball against falling out sure. The constriction can be done by caulking the edge of the hole.

In an alternative embodiment of the invention, it is proposed that the engagement pin at its end facing the sliding cam and the ejection ramp in the region of its outlet to the high circle each have a permanent magnet and a permanent magnet and that these permanent magnets are installed with oppositely directed polarity facing each other.

This embodiment of the invention ensures that the repulsive magnetic forces of the permanent magnet and the permanent magnet in the end region of the ejection ramp generate such a force that the engagement pin overcomes the resulting even at unfavorable tolerance residual stroke and moves securely in its inner end position.

Furthermore, it is expedient if the permanent holding magnet is surrounded on the engagement pin within the housing by a retaining cap or a retaining plate which is fastened to the engagement pin in order to fix the permanent retaining magnet securely on the engagement pin.

Brief description of the drawings

For further explanation of the invention reference is made to the drawings, in which embodiments of the invention are shown in simplified form.

Fig. 1:

einen Schnitt durch einen Schiebenocken und einen zugeordneten Aktor,

Fig. 2 u. 3:

Schnitte entsprechend Fig. 1, in denen unterschiedliche Einbautoleranzen dargestellt sind,

Fig. 4 u. 5:

Schnitte mit verschiedenen Toleranzlagen entsprechend den Fig. 2 und 3 in modifizierter Ausgestaltung der Erfindung,

Fig. 6 u. 7:

Schnitte durch Aktoren, die zu einer Baueinheit zusammengefasst sind, wobei die Eingriffsstifte dicht nebeneinander liegen.

Show it:

Fig. 1:

a section through a sliding cam and an associated actuator,

Fig. 2 u. 3:

Cuts accordingly Fig. 1 in which different installation tolerances are shown,

Fig. 4 u. 5:

Cuts with different tolerance positions according to the FIGS. 2 and 3 in a modified embodiment of the invention,

Fig. 6 u. 7:

Cuts by actuators, which are combined to form a unit, wherein the engagement pins are close together.

Detailed description of the drawings

In the FIGS. 1 to 7 is, as far as shown in detail, 1 denotes a camshaft of a reciprocating internal combustion engine, on the rotatably but slidably a sliding cam 2 is arranged, which has at least one groove 3 in addition to the cams for the gas exchange valves, which includes an ejection 4. The ejection ramp 4 extends to a designated 18 high circle of the sliding cam 2 in the region of the groove 3. Matching the groove 3, a generally designated 5 actuator is provided which has a housing 6, a coil 7 with a spool core 8 and an engagement pin 9 , The engagement pin 9 is arranged radially movable within the housing 6 with respect to the groove 3 and has in the interior a spring 10 which biases the engagement pin 9 in the direction of the sliding cam 2. The spool core 8 is adjacent to the engagement pin 9, a permanent holding magnet 11 is fixed, the magnetic force is greater than the force of the spring 10, which is supported at its inner end to the spool core 8. The permanent holding magnet 11 is enclosed by a retaining cap 12 which fixes it to the engagement pin 9. The engagement pin 9 further has at its the sliding cam 2 end facing a bore 13 in which a return spring 14 is installed, which loads a ball 15 in the direction of the sliding cam 2.

The ball 15 stands so far that it is pressed at least in the region of the ejection ramp 4 against the force of the return spring 14 in the bore 13, so that the return spring stores force that relaxes at the end of the ejector ramp and accelerates the engagement pin 9 so strong in that it arrives safely in the inner end position.

This will, like the FIGS. 2 and 3 can be seen, even larger tolerances bridged.

In the embodiments according to the FIGS. 4 and 5 9 permanent magnets 16 are installed on the sliding cam 2 facing ends of the engagement pins. Furthermore, the sliding cam 2 in the region of the end of the ejection ramp 4 permanent counter magnets 17 whose magnetic forces, as the arrows can be seen, are directed counter to each other. Now get the ends of the engagement pins 9 and thus the permanent magnet 16 in the rotation of the camshaft 1 and thus the sliding cam 2 in the area of the permanent magnet 17, the engagement pin 9 experiences a force and thus an acceleration away from the sliding cam 2, so that accordingly the embodiment according to the FIGS. 2 and 3 , the permanent holding magnet 11 reaches the spool core 8 safely.

Like that FIGS. 4 and 5 It can also be seen that larger tolerances are also bridged here.

In the FIGS. 6 and 7 the housing 6 is extended, so that each two engagement pins 9 can be installed close to each other and even a distance of only 5 mm can be achieved.

The ends of the engagement pins 9 are formed according to the previously described embodiments of the invention and equipped with permanent magnets 16 or balls 15.

LIST OF REFERENCE NUMBERS

1

camshaft

2

pushers

3

groove

4

ejection ramp

5

actuator

6

casing

7

Kitchen sink

8th

Plunger

9

engagement pin

10

feather

11

Permanent holding magnet

12

retaining cap

13

drilling

14

Return spring

15

Bullet

16

permanent magnet

17

Permanent counter magnet

18

high circle

Claims (6)

1. Actuator device of a sliding cam system, having at least one sliding cam (2) and having an engagement pin (9) which projects out of a housing (6), wherein the housing (6) can be fastened to a component of a cylinder head or to the cylinder head of an internal combustion engine, and the engagement pin (9) can be placed in contact with at least one groove (3) of the sliding cam system, which groove has at least one throw-out ramp (4) which is oriented in the direction of the housing (6) and which brings about a force acting on the engagement pin (9), and wherein the engagement pin (9) has, within the housing (6), a permanent holding magnet (11) and, adjoining the latter, is controlled by a static coil core (9) which can be magnetized by an electrical coil (7), and the engagement pin (9) is spring-loaded in the direction of the sliding cam (2), characterized in that, at least at that end region of the engagement pin (9) which faces toward the sliding cam (2), there is installed an actuating device which is active in the region in which the throw-out ramp (4) runs out at the high circle (18), which actuating device generates an auxiliary force - which arises in addition to the force brought about by the throw-out ramp (4) - on the engagement pin (9) in the direction of the housing (6), by means of which auxiliary force the engagement pin reliably reaches an inner end position.
2. Actuator device according to Claim 1, characterized in that the actuating device comprises, on that end of the engagement pin (9) which faces toward the sliding cam (2), an opening in which there is displaceably arranged an actuating element which is loaded in the direction of the sliding cam (2) by means of a restoring spring (14).
3. Actuator device according to Claim 2, characterized in that the actuating element is a ball (15) which is arranged in a bore (13) and the movement of which in the direction of the sliding cam (2) is limited by a constriction at the end of the bore (13).
4. Actuator device according to Claim 1, characterized in that the actuating device has, at that end of the engagement pin (9) which faces toward the sliding cam (2) and in the region in which the throw-out ramp (4) runs out at the high circle (18), respectively one permanent magnet (16) and permanent counter-magnet (17), and in that said permanent magnets are installed with opposite poles directed toward one another.
5. Actuator device according to one of the preceding claims, characterized in that the permanent holding magnet (11) on the engagement pin (9) is surrounded by a holding cap (12) which is fastened to the engagement pin (9).
6. Actuator device according to one of the preceding claims, characterized in that the sliding cam system has three or more cams and a corresponding number of grooves (3), and in that at least two actuators (5) are arranged adjacent to one another within a housing (6).

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