Abstract:
An electromagnetic actuator device has a coil unit ( 28, 58 ) enclosing a first yoke section ( 16, 56 ) of a stationary yoke unit ( 10, 54 ), an armature unit ( 14, 64 ) movably guided relative to the yoke unit ( 10, 54 ), by energisation to interact with a positioning partner on the output side of the armature unit ( 14, 64 ) and permanent magnetic agents ( 22, 36, 68 ) coupled into a magnetic flux circuit of the yoke unit ( 10, 54 ) wherein de-energisation of the coil unit ( 28, 58 ) a permanent magnetic flux circuit through the yoke unit ( 10, 54 ) and a section of the armature unit ( 14, 64 ) that is free of permanent magnetic flux and energisation displaces the permanent magnetic flux, out of the section, wherein the armature unit ( 14 ), by spring force is pre-loaded in a direction opposed to permanent magnetic retaining force of the armature unit ( 14, 64 ) and the positioning partner is a combustion engine unit.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention concerns an electromagnetic actuator device as well as the use of such an electromagnetic actuator device as a positioning device for a combustion engine unit. 
         [0002]    Electromagnetic positioning devices have been of known prior art for a long time as actuators, in particular for a camshaft positioning unit, or a similar unit of a combustion engine. Thus, for example, the applicant&#39;s German patent 102 40 774 shows such a technology, in which an armature unit having a permanent magnetic agent has at its end a tappet or tappet section designed to interact with a positioning partner (for example, a positioning groove of a camshaft adjustment system), and can be moved relative to a static yoke or core unit as a reaction to an energisation of a (stationary) coil unit. In concrete terms the reaction to the energisation in such devices is generated as a repulsive electromagnetic field, which releases the armature unit from an initial position on the yoke unit and drives it in the direction towards an engagement position with the positioning partner. 
         [0003]    Such devices of presupposed known art are not only electromagnetic and optimised with regard to their dynamic behaviour (force and velocity development); these devices are also suitable in a particularly beneficial manner for large-scale production. 
         [0004]    However, such an approach, as structurally determined, also has disadvantages, which in particular limit the flexibility of the adaptation of this technology to various conditions of deployment. Thus the technology presupposed as of known art, in the first instance the permanent magnetic agents (typically implemented in the form of a permanent magnetic disk or similar) to be provided on the armature and thus movable, requires protection of this armature unit from impacts, shocks or similar, so as to protect the typically brittle permanent magnetic material, and thus to ensure as long a service life as possible. DE 102 40 774, cited as prior art, solves this problem in that the armature-side permanent magnetic disk is bounded on both flat faces by (flux-conducting) metal disks and is additionally encased, so that even severe positive and negative accelerations onto the armature unit do not cause any damage to the permanent magnetic module. At the same time geometric limits are determined by such approaches, which, for example, define typical maximum sizes for such feasibility in the radial or axial directions. 
         [0005]    Thus there is a fundamental disadvantage of the technology of known art, namely that for purposes of increasing the forces the armature-side permanent magnetic agents must also be increased in size correspondingly, with the effect that the masses to be moved (by the armature) increase accordingly (in addition to the above-mentioned measures for the mechanical protection of the permanent magnetic material). 
       SUMMARY OF THE INVENTION 
       [0006]    Accordingly the fundamental requirement consists in increasing the flexibility of an electromagnetic actuator device that deploys permanent magnetic agents in terms of its configurability and adaptability, in particular to create the possibility of increasing the armature force without correspondingly increasing the mass to be moved by the armature (by means of correspondingly increased armature-side permanent magnetic agents). At the same time such a device should in particular be suitable for interaction with a positioning unit of a combustion engine, in particular as per further developments it should be able to exercise a camshaft adjustment system. 
         [0007]    The object is achieved by means of the electromagnetic actuator device with the features disclosed herein, together with the combustion engine unit adjustment device in accordance with the present disclosure, which likewise should be viewed as an application of an electromagnetic actuator device in accordance with the present invention in a combustion engine context. Advantageous further developments of the invention are also described herein. 
         [0008]    In an inventively advantageous manner the invention in the first instance relocates the permanent magnetic agents into the stator, i.e. into the flux-conducting stationary yoke unit; on its first yoke section this carries the stationary coil unit, which itself can suitably be energised, and with which the armature unit, which can move relative to the yoke unit, interacts so as to drive the latter. 
         [0009]    In accordance with the invention the electromagnetic actuator device is advantageously configured such that the permanent magnetic agents are coupled into the stationary yoke unit, i.e. form part of a (permanent) magnetic flux circuit consequently formed in the yoke unit. In accordance with the invention the yoke unit configured in this manner serves to ensure that in a de-energised state of the coil unit a section of the armature unit (more exactly: a yoke-side end of the armature unit, designed in the form of a tappet, which itself has no permanent magnetic agents) is part of the permanent magnetic flux circuit, accordingly therefore the permanent magnetic flux of the stationary permanent magnetic agents also flows through this section of the tappet unit (armature unit) and thus serves to ensure that in the de-energised state a retaining force holding the armature on the yoke unit is exerted. 
         [0010]    Likewise in accordance with the invention the energisation of the coil unit advantageously serves to ensure that the permanent magnetic flux is displaced from the armature unit by means of the electromagnetically generated flux, correspondingly the permanent magnetic retaining force onto the armature unit reduces. As a reaction to this can then the spring agent, provided in accordance with the invention, which acts in a suitable manner on the armature unit, can move the armature unit out of the initial position and release the armature unit from the yoke unit, since the related spring force is opposed to the permanent magnetic retaining force and exceeds the latter, with the displacement of the permanent magnetic flux out of the armature section. 
         [0011]    The result is that as a result of the action of the spring force the armature unit is brought into the desired end position, or engagement position, with the positioning partner, so that the desired positioning function can reliably be exercised on the combustion engine unit with few components and short switching times. 
         [0012]    Here in accordance with the invention, advantageously compared with the prior art called upon, the design of the permanent magnetic agents as stationary permanent magnetic agents can be in addition advantageously be deployed, i.e. integrated, into one or a plurality of sections of the actuator housing, suitably dimensioned for particular purposes, without this having any influence on the armature-side mass to be moved. Thus in the present invention it is in particular possible to influence an armature force without any corresponding influence of an armature-side permanent magnet occurring (which, for example, in the case of an increase would increase the additional mass to be accelerated). In this case it is just the static permanent magnet that must be dimensioned appropriately, here, for example, it must be increased. 
         [0013]    In accordance with the invention advantageously, and as per further developments, the inventive integration into the at least in some sections hollow cylindrical housing offers moreover the possibility of implementing suitable housing components with or from the permanent magnetic material, for example a cover section of the housing provided in accordance with further developments, and/or a section of a front face (which then, for example, can be in the form of a ring or a ring section) so that assembly and series production advantages can be implemented. 
         [0014]    As a result an actuator device designed to operate together with combustion engine units comes into being that is flexible to dimension and to configure; in particular it provides the possibility of dimensions that increase the magnetic force, without this having a disadvantageous effect on the armature mass (i.e. increasing the mass). As a result it is to be anticipated that the technology, already widely propagated and utilised, of the electromagnetic actuators that have been called upon as the initial technological starting point, can be made accessible to further applications. 
         [0015]    In an inventively advantageous further development adjacent flux-conducting agents are assigned to the permanent magnetic agents; these are configured such that (with an appropriate air gap Increasing the flux resistance), for example, the permanent magnetic flux displaced during the energisation of the coil unit can flow via these flux-conducting agents, and thus the magnetic flux characteristics can be additionally optimised. 
         [0016]    In a further preferred form of embodiment of the invention provision is made for the first yoke section (with the formation of an intermediately located air gap) to be aligned axially with the extended armature unit, such that a contact point therefore occurs between these sections. In this form of implementation the coil unit enclosing the first yoke section would therefore likewise be located coaxially with the extended tappet unit. With this variant of the invention it is possible to reproduce the form of the technology of known art in a particularly elegant manner, so that in this respect a direct substitution of existing electromagnetic actuators in accordance with the prior art can take place. 
         [0017]    Within the context of the invention it is particularly preferred in accordance with further developments to assign adjustment agents to the coil unit that enable particular modes of the energisation, in particular an adjustment of the polarity of the energisation, e.g. a reversal of this polarity. Since the present invention uses the principle of deploying electromagnetically generated magnetic flux for purposes of influencing, in particular for displacing permanent magnetic flux, and such a displacement requires opposing flux directions, the present invention likewise, and as an additional supplemental variant, envisages utilising the aligned fluxes (as a form of superposition) to an increased extent, so as not only to cause an increased retaining effect of the armature unit in a neutral state, initial state or retaining state on the yoke unit, but even if the armature unit is released from the yoke unit to generate a restoring force, i.e. a retraction force acting on the armature unit. This simply presupposes that a superimposed magnetic force (electromagnetic and permanent magnetic) acting on the armature unit in the released state is stronger than a spring force releasing the armature unit from the yoke unit, so that the adjustment agents as per further developments enable for the energisation in particular also a potentially increased current, for example, for the reversed polarity state as a retraction current. 
         [0018]    In this manner it is then in addition possible, as per further developments, depending upon the configuration of these adjustment agents for the coil unit, to configure the inventive device as a mono-stable or a bi-stable design. 
         [0019]    While one preferred form of implementation of the invention envisages a coil unit as an (individual) coil (for example from the point of view of efficient manufacture), it is equally within the framework of possible forms of embodiment to subdivide or configure the inventive coil unit in the form of a plurality of coils and to connect them together electrically with one another in a suitable manner, so that for example a required number of windings, instead of one large coil can be subdivided into a multiplicity of correspondingly smaller coils. Here too it is possible to ensure suitable geometrical optimisations to meet a particular requirement. Alternatively the first yoke section can be aligned orthogonally to the armature unit (or at another angle, forming an extended angle with the axial direction). 
         [0020]    In this manner the present invention is then extremely suitable for effecting an adjustment of the functionality of a combustion engine unit such as, for example, a camshaft, in which, in an installed environment with particular requirements, a dynamic, reliable and operationally secure adjustment functionality can be ensured. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    Further advantages, features, and details of the invention ensue from the following description of preferred examples of embodiment, and also with the aid of the drawings; in the latter: 
           [0022]      FIG. 1  shows a schematic view of the inventive electromagnetic actuator device with a first example of embodiment with a permanent magnetic unit integrated into the cover surface of the housing, represented in the de-energised operating state of the coil unit; 
           [0023]      FIG. 2  shows a representation analogous to  FIG. 1  of the first example of embodiment with an energised coil unit and a correspondingly modified magnetic flux; 
           [0024]      FIG. 3  shows a schematic representation of the first example of embodiment analogous to  FIGS. 1 ,  2  and, compared with  FIG. 2 , a reversed polarity energised state, so that instead of a flux displacement an increased magnetic flux flows via the tappet section; 
           [0025]    FIGS.  4 / 5 : show schematic views of an electromagnetic actuator device of a second example of embodiment with a permanent magnetic unit provided in the housing front face in the de-energised state ( FIG. 4 ) and in the energised displacement state ( FIG. 5 ) respectively; 
           [0026]      FIG. 6  shows a schematic representation of a third form of embodiment of the electromagnetic actuator device as a further development of the example of embodiment of  FIGS. 1 to 3 , with an additional flux-conducting unit, with air gap, adjacent to the permanent magnetic unit; 
           [0027]      FIG. 7  shows a fourth form of embodiment of the present invention with a coil unit mounted on the edge, and in turn a flux-conducting unit assigned to the permanent magnetic unit, and 
           [0028]      FIGS. 8-10 : show various variants for space-saving (compact) arrangements of a multiplicity of electromagnetic actuator devices of the example of embodiment of  FIG. 7 , in order in a particular installation context to enable deployment conditions that are as compact as possible. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]      FIGS. 1 to 3  illustrate in schematic form a first form of embodiment of the electromagnetic actuator device in three different operating states. Represented in the figures is a yoke unit  10 , consisting of a first yoke section  16  interacting axially across a front face air gap  12  with an extended tappet-type armature unit  14 , to which yoke section connects—in the figures transversely—a first front section  18 ; on the cover side the rotationally symmetric (and shown simply in its right-hand region) yoke unit, implemented as a housing, is provided with a cover flux section  20 , in which axially magnetised permanent magnetic agents  22  are deployed in a flux-conducting manner, as a ring in the example of embodiment represented. Facing the first front face end section  18  a second front face end section  24  is provided, which connects to the cylindrical housing cover  20 , and makes the magnetic connection to the tappet unit  14  across a lateral air gap  26 . 
         [0030]    The device so constructed thus possesses a cylindrical housing  18 ,  20 ,  24  with a first yoke section  16  designed along the central axis, which axially interacts with the armature tappet unit  14  (which has no permanent magnetic agents). In the housing interior, extending around the units  14 ,  16 , a coil unit is provided in the form of an individual coil  28 ; in the representations of  FIGS. 1 to 3  these are once again just the representations of the right-hand section of the otherwise radially symmetrical arrangements. 
         [0031]    The bundle of arrows  30  in  FIG. 1  illustrates the permanent magnetic flux through the magnetic circuit; it becomes apparent that the flux of the permanent magnetic unit  22  extends through the cover region  20 , the front face housing sections  18 ,  24 , and also the central yoke section  16 , and is closed by an end section  32  of the armature tappet (across the air gaps  12 ,  26 ). Accordingly there arises a magnetically attracting, i.e. retaining, force that fixes the armature tappet in the position shown in  FIG. 1  (in the de-energised state of the coil). Not shown in  FIGS. 1 to 3  is a compression spring acting on the armature unit in its direction of movement (downwards in the plane of the figure), i.e. pre-loading the armature unit in this direction; here the device in accordance with the first example of embodiment is configured such that the permanent magnetic retaining force exceeds an opposing compression force of this compression spring (not shown), so that the retaining state of  FIG. 1  is the de-energised neutral state. 
         [0032]    Compared with the state of  FIG. 1 ,  FIG. 2  shows the, energised state of the coil unit  28  (all other reference symbols, i.e. components thereby designated, apply in this respect in an analogous manner; the same is true for the later figures). It can be seen that the coil magnetic field (not shown) displaces the permanent magnetic flux (bundle of arrows  30 ′) from the end region  32 , i.e. from the first yoke section, so that the permanent magnet can no longer exert any retaining force on the armature unit. Accordingly the spring force acting on the armature unit at this point in time in the operation exceeds any retaining force, so that with a further passage of time the armature unit in its direction of movement (downwards in the figure) can be brought into an engagement position, where an engagement end  34  of the armature unit  32  can come into engagement with a related positioning partner, for example a positioning groove of a camshaft adjustment system of a combustion engine, and can effect the desired positioning operation. 
         [0033]    In a direct comparison with  FIG. 2  the schematic view of  FIG. 3  illustrates an energised control state of the coil unit  28 , of reverse polarity compared with the energisation state of  FIG. 2 . In this operating state an electromagnetically generated coil magnetic flux  40  runs parallel, i.e. overlapping, with the permanent magnetic flux  30 , illustrated by the double arrows shown, acts in this respect so as to increase the flux and therewith the force. Particularly preferably, through suitable control or adjustment agents of the coil unit, this is a pre-selectable mode, if, for example, a particularly strong retaining force is to be exerted on the armature unit (the state shown in  FIG. 3 ); additionally or alternatively even the armature unit against a corresponding compression force of the compression spring unit (not shown)—is to be restored into the initial state shown in  FIG. 1  and  FIG. 3 . In this respect the inventive reversal of polarity of the coil unit also enables a suitable mono-stable or bi-stable switching characteristic for the actuator device. 
         [0034]      FIGS. 4 and 5  show a second example of embodiment of the present invention; once again reference symbols that are the same as those in  FIGS. 1 to 3  illustrate identical or equivalent functional components, wherein once again  FIG. 4  illustrates the de-energised state and  FIG. 5  illustrates the energised functionality effecting the inventive displacement from the armature tappet. 
         [0035]    As  FIG. 4  illustrates in comparison to  FIG. 1 , here the permanent magnetic unit  36  shown is provided in the upper front face housing section  28 , once again with the rotational symmetry of the device the unit  38  would therewith correspond to e.g. a ring, which is inserted into a disk-shaped front face  18  and here, in terms of the flux, is coupled in a suitable manner. Additionally or alternatively, as in the first example of embodiment, the permanent magnetic unit can be a single body, or a multiplicity of bodies, which for example in the manner shown magnetised parallel to one another in the magnetic circuit and correspondingly is/are inserted into a mechanical void in the body. 
         [0036]    In the an analogous manner to the permanent magnetic flux of  FIG. 1  the permanent magnetic flux of the permanent magnet  36  runs through the yoke-side end section  32  of the tappet unit, and in this respect closes the permanent magnetic circuit with the formation of a retaining force exceeding the spring force of the spring agents (not shown), The energisation state,  FIG. 5 , once again causes the displacement of the permanent magnetic flux  30 ′ from this end section  32 , so that the spring agents, suitably acting on the armature unit, can with their pre-loading move the armature unit out of the neutral position shown into its engagement position, downwards along an armature direction of movement in the plane of the figure. 
         [0037]    As a variant to the example of embodiment of  FIGS. 1 to 3  and as a third form of embodiment,  FIG. 6  illustrates how, for purposes of further and additional influencing of the flux, for example in the form of a magnetic shunt, the form of embodiment of  FIGS. 1 to 3  is assigned to an additional magnetic circuit section, which consists of the e.g. U-shaped flux conducting section  50 , which has centrally an air gap  52  for purposes of increasing the magnetic resistance of this shunt, in this respect so as not to short-circuit the permanent magnetic flux of the permanent magnet  22  in every operating state. Such a further development enables the targeted influencing of the field displacement, namely into the shunt frame  50 ,  52  so that by this means a way is enabled to influence a magnetic characteristic of the device in a targeted manner. 
         [0038]      FIG. 7  shows with the fourth example of embodiment of the invention a further variant for the implementation of a practically usable electromagnetic actuator device. in principle comparable with the second example of embodiment of  FIGS. 4 ,  5 , here a stationary U-shaped arm is created as a yoke frame, with a first yoke section  56  (extending vertically), around which the coil unit  58  is formed. Laterally adjacent to the yoke section  56  is provided a further yoke section  60 , which interacts with an extended actuator unit  64  axially and via an air gap  62 . Once again the magnetic flux circuit of a permanent magnetic section  68  provided between the sections  60  and  56  is closed via an air gap  66  by means of a front face flux-conducting element  70 , which connects the first yoke section  56  (across the air gap  66 ) to the armature unit  64 . Additionally and in this respect in accordance with the principle of the example of embodiment of  FIG. 6 , a magnetic shunt element  72  is assigned to the adjacent permanent magnetic unit  68 , which across suitable air gaps  74 ,  76  provides space for the inventive flux displacement. 
         [0039]    In particular the form of implementation of  FIG. 7 , with the eccentric coil unit  58  opposite the armature tappet unit ( 64  in  FIG. 7 ), offers the possibility of assigning a multiplicity of such units in a compact, space-saving manner, and, for example, with the objective of implementing as short a separation distance as possible between adjacent tappet units. Such configurational options are shown in the schematic representations of  FIGS. 8 to 10 , which in this respect in each case indicate plan views onto the example of embodiment of  FIG. 7 , and, for example, in the example of  FIGS. 8 and 9 , illustrate how closely, in actual fact, a multiplicity of tappet units can be operated adjacent to one another, in order, for example, in a particular application context to be able also to solve a corresponding multiplicity of adjustment tasks.