EP3087575B1 - Electromagnetic actuating mechanism - Google Patents

Description

The present invention relates to an electromagnetic actuator according to the preamble of the main claim. Furthermore, the present invention relates to a camshaft adjusting system comprising such an electromagnetic actuating device in conjunction with a camshaft adjusting device of an internal combustion engine as preferred use of the electromagnetic actuating device.

From the prior art generic electromagnetic actuators are well known; that's how it describes them DE 201 14 466 U1 the applicant the structural design of such, used for camshaft adjustment actuator. When energizing a stationary coil unit, a relative to this and a stationary core unit movable armature unit is driven. An attached to the armature unit, elongated and end designed to engage in a camshaft adjustment of the adjusting ram unit is brought by the armature unit in an engaged position and causes in this the desired camshaft adjustment. The adjustment groove as an adjusting partner of the plunger means then also ensures (at least in sections) axial return of the plunger unit, namely in that a raised groove bottom induces a restoring movement.

In the practical realization of the generic type technology described above, in addition to reliable, reliable mass production suitability, it is above all the dynamics and the actuating force of the armature or plunger movement. So it is important that the plunger of a relatively short (predetermined by the control partner) time window can be brought from the initial position into the engaged position, which is high Magnetic forces (on the one hand when overcoming permanent magnetic holding forces of the armature unit at the core area, on the other hand to achieve a high anchor acceleration) requires. Added to this is the fact that in the generic technology used the repulsion force (and thus acting on the armature unit acceleration force) must act the restoring force for returning the armature unit over the entire effective stroke; However, long strokes then lead, in particular in conjunction with high accelerated masses, to a high mechanical loading of the components, again with the requirement of a correspondingly more robust design of the assemblies. The result is undesirably high (and costly) overhead for the mass-produced actuators. Finally, aging and temperature effects, in particular in the case of the permanent magnet means usually provided on the armature side, must be taken into account, which require additional design reserves in the concrete realization.

From the DE 10 2012 101 619 A1 the applicant is an electromagnetic actuator known, which has radially-laterally engaging on the armature plunger locking means. These latching means make it possible to increase the dynamics of the armature and plunger movement, by triggering the latching means only after exceeding a predetermined force and thus the adjustment movement takes place within a shortened positioning time. However, there is also the disadvantage discussed above that, in principle, the actuating force must be generated over the entire effective actuating stroke of the combined armature and tappet unit, as well as the provision must be made opposite the entire stroke. Accordingly, in principle, the same increased (and disadvantageous for the reasons discussed above) sizing arise as in the generic, generic prior art.

The object of the present invention is therefore, with improved (in particular accelerated and gleichmäßigtem) control behavior of the plunger means to reduce the requirements of magnetic force and magnet arm of the armature unit, thus potentially the size of a generic electromotive actuator (both in the radial, and potentially in the axial direction) to reduce and thus to provide a device which combines favorable dynamic properties with a comparatively long effective working stroke of the plunger means.

The object is achieved by the electromagnetic actuator with the features of the main claim. Advantageous developments of the invention are described in the subclaims. Additional protection within the scope of the invention is claimed by the use of the electromagnetic actuator according to the invention in the context of a camshaft adjusting system, wherein a camshaft adjusting unit of an internal combustion engine offers an adjusting groove as an adjusting partner for engagement by the ram means according to the invention.

In an advantageous manner according to the invention, in contrast to the prior art, the armature unit provided movable relative to the plunger means, so that the armature unit (preferably along its armature stroke) drive and can take along the plunger means, but the plunger means movable relative to the armature unit additionally a plunger stroke caused by the spring means according to the invention, can perform, which is inventively larger than the armature stroke itself. According to the invention, the axially coupled arrangement of armature unit and plunger means cooperates with force application means acting on the shell side on the plunger means in the form of the pressure body according to the invention, which has adjacent ramps both with the ramp or cone section on the plunger means and with the plunger sections of larger or smaller diameter - or cone section cooperate can. Specifically, this arrangement is designed and dimensioned such that the armature unit entrains the plunger means along the direction of movement during its armature movement, whereby the plunger means are advanced as far as the (at least one, preferably radially predominantly distributed) pressure body until the cone or ramp (related to the / the pressure body) is overcome. The further feed then happens by expansion of the spring means according to the invention (which have already already supported the armature movement to the armature stroke). As a result, so that the combined action of both the anchor means, as well as the spring means, on the plunger means to an effective ram stroke, which is greater than the actual armature stroke; in practical embodiments of the invention, at least a factor of 1.5, more preferably at least a factor of 2.5.

An advantageous consequence is that the adjusting device according to the invention can be dimensioned to a much smaller armature stroke (with corresponding advantages of the mechanics and the construction volume), relative to an achievable control stroke.

The ramp or cone section according to the invention has an equally advantageous effect on the return of the adjusting device or the plunger means to the starting position. Thus, according to the invention, it is sufficient if the plunger means are reset from the engagement position (for example, by the engagement in the adjustment groove provided in the preferred use form "camshaft adjustment") only so far against the direction of movement, until - axially - the pressure body (s) reaches the ramp. or cone section reaches / s. At that time, namely, the shell-side force acting on the ramp or cone section to a further provision or force application of the plunger means in the direction of the starting position lead, without this (in addition to the adjusting partner) Rückstellhub further contact with the control partner requires or otherwise driven externally. Again, advantageous effect also for the return movement, that the anchor unit itself must have an armature stroke smaller than the ram stroke.

While it is preferred in the context of preferred developments of the invention to design the pressure body as a ball or spherical portion of a differently shaped pressure body, other variants are conceivable; It is nevertheless advantageous to arrange the pressure body, more preferably pretensioned by the pretensioning force of a compression spring which is preferably oriented radially to the direction of movement, in a plurality and around a circumference of the plunger means, so that a reliable influencing of the plunger movement by these pressure bodies can take place ,

If a spring force vector of the pressure body biasing (pressure) spring has a radial component, a concrete arrangement of the spring is arbitrary and may depend on the circumstances in the surrounding housing; This also applies to the specific design of a spring.

In the context of specific and preferred embodiments of the invention, the geometry of the ramp or cone section is important; In practical implementation, it has been found preferable to provide an extension of the ramp or cone section, which is greater than a (maximum) axial extent of the pressure hull, that is about a ball diameter. It is also advantageous in terms of further development to set the axial extent of the ramp or cone section in relation to the armature stroke in such a way that, as a result of the armature movement along the armature stroke, a major part of the axial travel of the pressure body along the armature Rampen- or cone section can be overcome, for which purpose preferably the ramp or cone section corresponds approximately to the armature stroke, according to the invention further developing 50% to 150%, preferably 80% to 120% of the anchor stroke.

Equally useful in the context of developments of the invention, a pitch angle of the Rampen- or cone section (as measured in longitudinal section relative to the longitudinal axis of movement) in the range between 20 ° and 60 °, preferably between 30 ° and 50 ° to provide.

In a structurally particularly favorable manner, it is provided according to further development, the spring means, more preferably realized as a pressure and / or coil spring, in a (hollow cylindrical) interior of the radially symmetrical tappet means provided; For this purpose, the plunger means may have approximately a hollow cylindrical interior and / or an inner annular shoulder. At the other end, the spring means would then be able to support, for example, a portion of a housing guiding the plunger means, so that according to the invention the spring means can make their contribution to accelerating the plunger unit, wherein the armature unit can continue to have permanent magnet means as before and in otherwise known manner, alternatively but also electromagnetically operable in other ways relative to the stationary core unit.

It is particularly preferred in the context of developments of the invention also, the armature unit (or caused in the actuator electromagnetic drive of the armature unit) monostable to design, ie only provide an anchor initial position as a single stable end position, in which case while energizing the coil means though the armature unit is moved around the armature, after completion of the energization, however, the armature unit falls back into the armature's starting position. This configuration is advantageous in cooperation with the plunger means in that the armature unit after the initial driving of the plunger means makes no contribution to further advancement of the plunger means (this is rather taken over by the spring means) while then returning, in particular by the interaction between the pressure body and Rampen- or cone section, no additional return or take along the anchor unit is necessary in the starting position.

As a result, an apparatus is provided by the present invention which significantly prolongs effective stroke length of existing generic actuators without requiring equally larger or bulkier magnet assemblies. Accordingly, there are significant advantages, in particular for the preferred application context "camshaft adjustment", not least in the manufacturing effort and in the space required installation space. However, the present invention is not limited to this application context, but rather is also suitable for any other actuating applications in which long staging strokes are to be realized with limited electromagnetic means.

Fig. 1

eine schematische Längsschnittdarstellung der elektromagnetischen Stellvorrichtung gemäß einer ersten bevorzugten Ausführungsform der Erfindung, symbolisch geteilt entlang der vertikalen Symmetrie- und Bewegungsachse in eine zurückgezogene Ausgangsstellung (rechts) und einen Eingriffszustand (links) relativ zu einer Nockenwellen-Schaltkulisse als Eingriffspartner.

Further advantages, features and details of the present invention will become apparent from the following description of preferred embodiments and with reference to the single figure; this shows in:

Fig. 1

a schematic longitudinal sectional view of the electromagnetic actuator according to a first preferred embodiment of the invention, symbolically divided along the vertical axis of symmetry and movement in a retracted initial position (right) and an engaged state (left) relative to a camshaft shift gate as engagement partner.

In the Längsnutdarstellung the Fig. 1 the reference numeral 10 symbolically shows an armature unit with an elongated armature tappet 12 and an armature body 14 which is widened relative to it. By means of an armature coil (not shown in the figure), the armature unit 10 is movable in an otherwise known manner relative to a stationary core unit (not shown), between an anchor home position ( Fig. 1 , right) and an armature feed position ( Fig. 1 , left half). In a practical implementation, a typical armature stroke is in the range between 1 and 1.5 mm with an effective stroke of the plunger means of about 4 mm.

As the Fig. 1 schematically further illustrated, engages the anchor tappet portion 12 inside of a plunger unit (plunger means) 16, which is guided in a surrounding plunger housing 18. Like the longitudinal section of the Fig. 1 can be seen, in the direction of the armature unit 10, the plunger unit 16 is open on the bottom side for receiving the armature tappet portion 12; this is dimensioned so that it is in the anchor position ( Fig.1 , right half) a - small - distance from the plunger complies and only at feed the plunger 16 then along the direction of movement (in the plane of the figure Fig. 1 down).

In addition to a bottom or an annular shoulder 20 of the plunger unit 16 attacking a coil spring 22 is shown, which is supported at the other end of a ring bottom 24 of the plunger housing 18. In the right half of the Fig. 1 As far as corresponding to the initial position of the plunger means 16, the coil spring 22 is correspondingly compressed and exerts a maximum bias on the plunger unit 16 in the downward direction of movement.

The ram unit 16 has, in the direction of the armature unit 10, a tappet portion 26 larger outside diameter; via a cone section 28, this (larger) outer diameter tapers in an engagement-side front tappet section 30 of reduced outer diameter. As the longitudinal sectional view reveals, the cone section 28 extends over an axial length of about 1.2 mm at an angle with respect to the vertical axis of motion of about 25 °. In that regard, the axial extent (axial length) of the cone portion 28 corresponds to the armature stroke, plus the (gap) distance between an engagement end 34 of the plunger unit and the actuator in the disengaged state.

As the Fig. 1 can additionally recognize, grip pressure body 32 in the form of distributed around the circumference of the plunger unit 16 around balls on the lateral surface of the plunger unit; These balls 32 are biased by their own, horizontally (and thus radially to the longitudinal movement axis) extending compression springs 33.

Engaging side, i. opposes the armature unit 10, the plunger unit 16 forms the engagement portion (engagement end) 34, which is dimensioned to cooperate with a shift groove 36 of an exemplary shown as a control partner shift gate 38 of a camshaft adjustment system; the double arrow 40 illustrates the groove depth in the example shown by about 3.7 mm, which is covered by the ram stroke (here about 4 mm).

• Aus der Ausgangslage der Ankereinheit (rechte Hälfte der Fig. 1) erfolgt durch Bestromung der (nicht gezeigten) Spulenmittel zunächst eine Bewegung der Ankereinheit (bestehend aus dem Ankerkörper 14 und dem direkt und fest ansitzenden, alternativ (permanent-)magnetisch haftend ansitzenden Ankerstößel 12) entlang der Bewegungsrichtung, also in Fig. 1 abwärts; der Ankerhub liegt im Bereich zwischen ca. 1 und 1,5 mm. Bei Erreichen des Widerlagers 20 der Stößeleinheit 16 wird diese entlang der Bewegungsrichtung mitgenommen; gleichzeitig schiebt sich der Konusabschnitt 28 in Richtung abwärts entlang der horizontal feststehenden kugelförmigen Druckkörper 32, bis diese auf dem (oberen) zylindrischen Mantelabschnitt 26 der Stößeleinheit liegen. Während die sich entspannende Druckfeder 22 bereits die Ankerbewegung unterstützt hat und insoweit eine zusätzliche, abwärtsgerichtete Stellkraft auf die Stößeleinheit 16 ausgeübt hat, übernimmt die Druckfeder 22 vollständig den weiteren, abwärtsgerichteten Vorschub der Stößeleinheit 16, sobald die Ankereinheit ihren Anschlagszustand am Gehäuse 18 erreicht (Fig. 1, linker Bereich für den Ankeranschlag); während die Feder 22 die Stößeleinheit weiter abwärts führt, trennt sich der Ankerstößelabschnitt 12 von der Stößeleinheit 10.

Operation of in Fig. 1 shown device is as follows:

• From the initial position of the anchor unit (right half of Fig. 1 ) is carried out by energizing the coil means (not shown), first a movement of the armature unit (consisting of the anchor body 14 and the directly and firmly ansitzenden, alternatively (permanently) magnetically adhering anchoring anchor plunger 12) along the direction of movement, ie in Fig. 1 down; the armature stroke is in the range between approx. 1 and 1.5 mm. Upon reaching the abutment 20 of the plunger unit 16, this is taken along the direction of movement; At the same time, the cone section 28 slides in the downward direction along the horizontally fixed spherical pressure body 32, until they lie on the (upper) cylindrical shell portion 26 of the plunger unit. While the relaxing compression spring 22 has already supported the armature movement and so far has exerted an additional, downward force on the plunger unit 16, the compression spring 22 completely takes over the further, downward feed of the plunger unit 16 as soon as the armature unit reaches its stop state on the housing 18 ( Fig. 1 left armature stop area); while the spring 22 continues to lower the ram unit, the armature tappet portion 12 separates from the ram unit 10.

The left area of the Fig. 1 shows the fully ejected state of the armature plunger 16 from the housing 18. The plunger unit 16 has a total stroke of about 4 mm performs and engages in this state in the groove 36 of the adjusting partner 38 a. Upon rotation of the assembly 38, the camshaft adjustment takes place in an otherwise known manner.

The adjusting groove 36 also causes the return of the plunger 16 along a first return stroke section; Concretely, a decreasing groove depth (upon rotation of the gate 38) causes the plunger unit 16 to move in the return direction (ie in the plane of the figure) Fig. 1 pushed upward). The device shown here is dimensioned such that this provision takes place axially as far along the first return stroke until the balls 32 engaging on the cylindrical lateral surface 26 reach the beginning of the cone section 28 (acting as a ramp). To this Time then leads the radial application of force to the balls 32 as a pressure body to that along the conical surface, the return movement is continued in the direction of the starting position, the cone so far a subsequent to the first return stroke of the groove second return stroke, to the in the Fig. 1 right starting position, determined. Since the anchor unit 10 is designed monostable in the manner described above, the plunger unit 16 in this return operation does not additionally reset the anchor unit 10 with (about by entrainment of the section 12), but took place immediately after the Bestromungsende already when taking out the plunger 16 is a falling back the anchor unit 10 in its monostable end position ( Fig. 1 , right). Alternatively, a bistable design, for example by means of a permanently magnetically realized anchor body 14, be useful, especially with regard to a so realized (magnetic field detected) position, motion and / or reset device.

Claims (12)

1. Electromagnetic actuating device comprising
   an armature unit (10) which is able to be driven by supplying current to stationary coil means by an armature stroke in an axial direction of movement,
   plunger means (16) which are assigned to the armature unit, which are configured on the end side for cooperating with an external actuating partner and which are movable by a plunger stroke from an initial position into an engagement position in the direction of movement
   and spring means (22) which pretension the plunger means in the direction of movement,
   characterised in that the plunger means, which are movably guided relative to the armature unit, on the shell side comprise a ramp section and/or cone-shaped section (28) between a plunger portion of larger diameter (26) on the armature side and a plunger portion (30) with a smaller diameter,
   a pressure body (32), which is contained under pretensioning in a housing portion (18) guiding the plunger means, cooperates on the shell side with the ramp section and/or cone-shaped section
   and the ramp section and/or cone-shaped section is provided on the plunger means such that the pressure body, when the coil unit is not supplied with current and/or when the armature unit is not driven, by the action of force on the shell side on the ramp section and/or cone-shaped section, returns the plunger means counter to the pretensioning of the spring means in the direction of the initial position, in particular into the initial position,
   wherein the armature stroke is smaller than the plunger stroke.
2. Device according to Claim 1, characterised in that the pressure body is configured as a ball (32) or a body comprising a spherical segment and is preferably provided in the form of a plurality of pressure bodies arranged so as to be distributed around a periphery of the plunger means.
3. Device according to Claim 1 or 2, characterised in that the ramp section and/or cone-shaped section (28) has an extent in the axial direction of movement which is greater than a diameter or an axial extent of the pressure body and/or is between 50% and 150%, preferably between 80% and 120%, of the armature stroke.
4. Device according to one of Claims 1 to 3, characterised in that the ramp section and/or cone-shaped section (28) is inclined along the longitudinal section by an angle (α) of between 20° and 60°, preferably of between 30° and 40°, relative to the longitudinal axis of the direction of movement.
5. Device according to one of Claims 1 to 4, characterised in that the plunger stroke is at least 1.5 times, preferably at least 2.5 times, the armature stroke.
6. Device according to one of Claims 1 to 5, characterised in that the plunger means (16), which are implemented radially symmetrically about the longitudinal axis of movement in the direction of movement, comprise an internal widening for receiving the spring means configured as a spiral spring and/or an internal shoulder providing a stop (20) for the spring means, in particular an annular shoulder.
7. Device according to Claim 6, characterised in that the spring means which are configured as a compression spring and/or spiral spring (22) are supported at one end on the plunger means (16) and at the other end on a portion (24) of the housing (18) guiding the plunger means.
8. Device according to one of Claims 1 to 7, characterised in that the armature unit is configured to be monostable such that after germinating the supply of current the armature unit drops back into an armature initial position.
9. Device according to Claim 8, characterised in that the armature unit is dimensioned and designed such that in the armature initial position no mechanical contact exists with the plunger means.
10. Device according to one of Claims 1 to 9, characterised in that the plunger means are configured for cooperating with an actuating groove (36) as an actuating partner, such that a change in the position and/or depth of the actuating groove may effect a movement of the plunger means in a restoring direction opposing the direction of movement,
11. Device according to one of Claims 1 to 10, characterised in that the armature unit comprises permanent magnet means which are configured for cooperating with means for detecting the position, movement and/or restoring of the armature unit.
12. Cam shaft adjusting system comprising the electromagnetic actuating device according to one of Claims 1 to 11, and an actuating groove (36) as an actuating partner for engagement by the cam shaft adjusting unit (38) of an internal combustion engine, said cam shaft adjusting unit providing plunger means,
    wherein the actuating groove and the plunger means are configured and axially aligned relative to one another such that the actuating groove may perform a first restoring stroke onto the plunger means counter to the direction of movement and the first restoring stroke may move the pressure body onto the ramp section and/or cone-shaped section in order to bring about an axially aligned, preferably a subsequent, second restoring stroke by the action of force on the shell side.

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