EP3087575A1

EP3087575A1 - Electromagnetic actuating mechanism

Info

Publication number: EP3087575A1
Application number: EP14828454.0A
Authority: EP
Inventors: Timo Rigling
Original assignee: ETO Magnetic GmbH
Current assignee: ETO Magnetic GmbH
Priority date: 2013-12-23
Filing date: 2014-12-18
Publication date: 2016-11-02
Anticipated expiration: 2034-12-18
Also published as: US20160322146A1; EP3087575B1; CN105830179B; DE102013114830A1; WO2015097068A1; US9741481B2; CN105830179A

Abstract

The invention relates to an electromagnetic actuating mechanism comprising an armature unit (10) which can be moved by a certain armature excursion along an axial direction of travel as a result of stationary coil means being energized, plunger means (16) which are associated with the armature unit, are designed such that the end thereof cooperates with an external actuating partner, and can be moved by a certain plunger excursion along the direction of travel from a starting position into an engagement position, and spring means (22) which bias the plunger means in the direction of travel. The plunger means are guided so as to be movable relative to the armature unit and are externally provided with a ramp section and/or conical section (28) between a plunger section that has a larger diameter (26) and is located at the end facing the armature and a plunger section (30) having a smaller diameter. A pressure member (32) which is accommodated in a biased state in a housing sector (18) guiding the plunger means externally cooperates with the ramp section or conical section, the ramp section or conical section being designed on the plunger means in such a way that if the pressure member applies force to the ramp section or conical section, the pressure member returns the plunger means in the direction of the starting position, in particular into the starting position, against the bias of the spring means when the coil unit is not energized and/or the armature unit is not moved, the excursion of the armature being smaller than that of the plunger.

Description

Electromagnetic actuator

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

From the prior art generic electromagnetic actuators are well known; For example, DE 201 14 466 U1 by the applicant describes the structural design of such an adjusting device used for camshaft adjustment. 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 Verstellnut the adjusting device 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 genre-forming technology, the repulsive force (and thus the acceleration force acting on the armature unit) has to act on the restoring force for returning the armature unit over the entire effective working 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 DE 10 2012 101 619 A1 of the Applicant an electromagnetic actuator is 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. Correspondingly, the same increased (and disadvantageous for the reasons discussed above) dimensioning requirements arise in principle as in the generic, gatungsbildenden state of the art. It is therefore an object of the present invention, with improved (in particular accelerated and uniformized) actuating behavior of the plunger means, to reduce the requirements of magnetic force and magnet stroke of the armature unit, thereby potentially reducing the size of a generic electromotive actuating device (both in the radial and also in the axial Direction) and thus to provide a device which combines favorable dynamic characteristics 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 in the context 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 plunger 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, the combined action of both the anchor means and the spring means on the plunger means results in an effective plunger stroke which is greater than the actual armature stroke; in practical embodiments of the invention, at least by a factor of 1.5, more preferably by 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) follow the ramp. At this point in time, the action of the shell-side force on the ramp or cone section would then lead to a further return or application of force to the ram 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 the practical realization, it has been found preferable to provide a first recess of the ramp or cone section, which is larger than a (maximum) axial extension of the pressure body, that is to say 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 the further development of the spring means, more preferably realized as a pressure and / or coil spring, in a (hollow cylindrical) inner region 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 supported on a portion of a housing guiding the plunger means, so that according to the invention the spring means can make their contribution to the acceleration of the plunger unit, wherein the armature unit can continue to comprise permanent magnet means as before and in an otherwise known manner Alternatively, however, it can also be actuated electromagnetically in a different manner 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 design, ie only provide an anchor initial position as the only stable end position, in which case while energizing the coil means though the armature unit is moved around the armature, however, after completion of the energization, the armature unit is moved into the armature's starting position. back falls. 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. Correspondingly, there are significant advantages, in particular for the preferred application context "camshaft adjustment", not least in the production costs and installation space required in the saving, but the present invention is not limited to this application context, but rather is also suitable for any other actuating applications in which there are limited electromagnetic means long strokes are to be realized.

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:

1 is 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 withdrawn initial position (right) and an engaging condition (left) relative to a camshaft shift gate as engagement partner.

In the longitudinal groove illustration of 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. The armature unit 10 is wound relative to the armature coil (not shown in the drawing) in an otherwise known manner a stationary core unit (not shown) movable between an armature initial 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 FIG. 1 further schematically illustrates, the armature tappet section 12 engages on the inside on a tappet unit (tappet means) 16, which is guided in a surrounding tappet housing 18. 1, in the direction of the armature unit 10, the tappet unit 16 is open on the bottom side for receiving the armature tappet section 12; this is dimensioned so that it maintains a - small - distance from the plunger in the armature initial position (Fig.1, right half) and then along the direction of movement (in the plane of FIG. 1 down) only on feed the plunger 16 ,

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 FIG. 1, insofar as corresponds to the starting position of the plunger means 16, the coil spring 22 is correspondingly compressed and exerts a maximum preload 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 conical section 28, this (larger) outer diameter tapers in a front-tappet section 30, which has a reduced external diameter, on an engagement-side front tappet section. As can be seen from the longitudinal sectional view, the cone section 28 extends over an axial length of approximately 1.2 mm at an angle with respect to the vertical movement axis of approximately 25 °. In that regard, the axial extension (axial length) of the cone section 28 corresponds to the armature stroke, plus the (gap-laden) distance between an engagement end 34 of the tappet unit and the control partner in the disengaged state.

As can be additionally seen from FIG. 1, pressure bodies 32 grip the lateral surface of the tappet unit in the form of balls distributed around the circumference of the tappet unit 16; These balls 32 are biased by their own, horizontally (and thus radially to the longitudinal movement axis) extending compression springs 33.

Engaging side, i. Opposite 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 a switching gate 38 of a camshaft adjustment system shown by way of example as a control partner; The double arrow 40 illustrates the groove depth in the example shown of approximately 3.7 mm, which is covered by the ram stroke (here approx. 4 mm).

The operation of the apparatus shown in Fig. 1 is as follows:

From the starting position of the armature unit (right half of FIG. 1), energization of the coil means (not shown) is first followed by movement of the armature unit (consisting of the armature body 14 and the armature directly and firmly ansitzenden, alternatively (permanently) magnetically adhering anchoring anchor plunger 12) along the direction of movement, ie in Fig. 1 downwards; the armature stroke is in the range between about 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 guide the ram unit downwards, the armature tappet section 1 2 separates from the ram unit 10.

The left portion of 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 be pushed in the return direction (ie, upwards in the plane of the figure). 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 FIG. 1 starting position shown on the right, 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, may be useful, in particular also with regard to a (magnetic field detected) position, motion and / or reset detection.

Claims

claims

1 . Electromagnetic actuator with

an armature unit (10) which can be driven by an armature stroke by energizing stationary coil means along an axial direction of movement,

associated with the armature unit, the end formed to cooperate with an external actuator and a plunger stroke from a starting position in an engaged position along the direction of movement movable plunger means (16)

and the plunger means in the direction of movement biasing spring means (22),

characterized,

the ram means movably guided relative to the armature unit have on the shell side a ramp and / or cone section (28) between an armature-side ram portion of larger diameter (26) and a ram portion (30) of smaller diameter,

a pressure body (32), which is under bias in a housing section (18) carrying the plunger means, cooperates with the ramp or cone section on the shell side

and the ramp or cone section is provided on the plunger means in such a way that, when the coil unit is not energized and / or the armature unit is not driven, the plunger means against the bias of the spring means in the direction of the Initial position, in particular in the starting position, leads back

wherein the armature stroke is smaller than the ram stroke. Device according to claim 1,

characterized,

the pressure body is designed as a ball (32) or a body having a ball portion and is preferably provided in the form of a plurality of pressure bodies distributed around a circumference of the tappet means.

Apparatus according to claim 1 or 2,

characterized,

in that the ramp or cone section (28) has an extension along the axial direction of movement that is greater than a diameter or an axial extension of the pressure body and / or between 50% and 150%, preferably between 80% and 120%, of the armature stroke is.

Device according to one of claims 1 to 3,

characterized,

the ramp or cone section (28) is inclined longitudinally at an angle (a) between 20 ° and 60 °, preferably between 30 ° and 40 °, to the longitudinal axis of the direction of movement.

Device according to one of claims 1 to 4,

characterized,

the ram stroke is at least 1.5 times, preferably at least 2.5 times, the anchor stroke.

Device according to one of claims 1 to 5,

characterized,

in that the ram means (16) realized radially symmetrically about the movement longitudinal axis of the direction of movement have an internal lying Expansion for receiving the spring means designed as a spiral spring and / or an abutment (20) for the spring means offering inner shoulder, in particular annular shoulder, have.

Device according to claim 6,

characterized,

in that the spring means formed as a pressure and / or spiral spring (22) are supported at one end on the plunger means (16) and at the other end against a portion (24) of the housing (18) guiding the plunger means.

Device according to one of claims 1 to 7,

characterized,

in that the armature unit is monostable in such a way that, after termination of the energization, the armature unit falls back into an armature initial position.

Device according to claim 8,

characterized,

that the anchor unit is dimensioned and set up so that there is no mechanical contact with the plunger means in the anchor initial position.

Device according to one of claims 1 to 9,

characterized,

in that the plunger means are designed to cooperate with an adjusting groove (36) as an adjusting partner such that a position change and / or a depth change of the adjusting groove can cause the plunger means to move in a return direction opposite to the direction of movement. Device according to one of claims 1 to 10,

characterized,

in that the armature unit has permanent magnet means which are designed to cooperate with means for detecting the position, movement and / or return of the armature unit.

Camshaft adjusting system comprising the electromagnetic adjusting device according to one of claims 1 to 1 1 and an adjusting groove (36) as an adjusting partner for engagement by the plunger means offering camshaft adjusting unit (38) of an internal combustion engine,

wherein the adjusting groove and the plunger means are formed and axially aligned with each other, that the adjusting groove can exert a first return stroke on the plunger means against the direction of movement and the first return stroke the pressure body to the ramp or cone section to effect an axially rectified, preferably subsequent second Return stroke can move through the shell-side force.