EP3918619B1 - Electromagnetic actuator - Google Patents

Description

The invention relates to an electromagnetic actuating device with at least one electromagnetic actuator unit, the actuator unit having a coil and a plunger, which plunger can be moved axially relative to the coil by energizing the coil, the actuator unit being arranged in a housing.

Various actuator units of the type mentioned at the outset have become known from the prior art. Such actuator units are used in particular for a camshaft adjustment device. In order to enable camshaft adjustment in different directions, for example to be able to operate an engine with two or more different cam geometries, adjusting devices with at least one actuator unit, preferably several independently controllable actuator units, are required, with the actuator units being only a few millimeters apart. For this purpose, for example, from DE 10 2007 028 600 B4 a corresponding device has become known with which several plungers can be actuated in a limited space. The disadvantage of this device is that it can only be produced with great effort and is therefore very expensive.

This is where the invention comes in. The object of the invention is to specify an adjusting device of the type mentioned at the outset, which can be produced in a simpler and more cost-effective manner and still meets requirements with regard to a required service life.

Electromagnetic actuators according to the preamble of claim 1 are from documents DE 10 2017 115 975 A1 and DE 10 2008 029 324 A1 known.

According to the invention, this object is achieved by an adjusting device of the type mentioned at the outset, in which the plunger is arranged approximately coaxially with the coil.

In the context of the invention it was recognized that the production in the document DE 10 2007 028 600 B4 The device described is so complex because the plungers are arranged eccentrically to the coils, so that when the plungers are actuated, an eccentric force is applied to the plungers, which generates a moment about a transverse axis of the usually approximately parallel plungers, which is perpendicular to a longitudinal axis of the Plunger is causes. This moment must be marked by a special complex guidance of the ram must be taken into account in order to avoid tipping of the ram.

After the actuator unit is arranged approximately centrally to the coil in the actuating device according to the invention, so that a longitudinal or central axis of the coil coincides approximately with a longitudinal axis of the plunger assigned to the coil and the plunger is approximately coaxial with the coil, a corresponding moment is generated here about a transverse axis, ie about an axis perpendicular to the longitudinal axis, avoided in a simple manner, so that a complex ram guide can be dispensed with. With the structure according to the invention, a lower load is thus achieved, which is why a long service life can be guaranteed despite the simpler storage. Although the actuating device according to the invention can in principle be designed with a single actuator unit or any number of actuator units, it is particularly favorable if exactly two actuator units are arranged in an actuating device in order to achieve a compact design. It goes without saying that in an embodiment with a plurality of actuator units, each actuator unit is generally designed according to the invention.

For use of the adjusting device for cam adjustment in an internal combustion engine, it is particularly favorable if at least two actuator units are provided, the tappets of all actuator units being arranged approximately coaxially with the coils, with all actuator units preferably being arranged in a common housing. As a result, a sleeve on a camshaft can be moved axially in a simple manner. Because of this construction, a particularly small distance between the tappets is possible with a simple and inexpensive construction at the same time.

It is favorable if the ram, preferably each ram in the case of an actuating device with a plurality of actuator units, can be moved from an end position close to the core to an end position remote from the core, the ram abutting against stops in each of the end positions. As a result, movements of the rams are predefined in a simple manner with a high level of accuracy. The stops are usually formed by metallic components, in particular made of a magnetizable material.

Normally, the actuating device is designed as a bistable actuating device, so that the ram or rams remain stable in the end positions when the coils are de-energized.

Provision is preferably made for a permanent magnet to be arranged on the plunger, preferably on each plunger in the case of an actuating device with a plurality of actuator units. As a result, the rams automatically adhere in the end positions and thus a bistable device is provided in a simple manner.

A particularly simple structure results when the coil, preferably each coil in the case of an actuating device with a plurality of actuator units, is arranged around a core, with the permanent magnet being magnetically separated from the core in the axial direction only by an air gap. Thus, no further device, in particular no metallic or magnetizable device such as an anchor element, is provided between the permanent magnet and the core. The core is usually made of a material that conducts magnetic flux very well, for example leaded soft machining steel.

Provision is preferably made for an anchor element, in particular an anchor plate, to be arranged on the plunger, preferably on each plunger in the case of an actuating device with a plurality of actuator units. The armature element, which is usually made of a magnetizable metal, is usually rigidly connected to the ram, for example via a laser weld seam, and can be moved by energizing the coil via the resulting magnetic field, so that a force is exerted on the ram via the armature plate by energizing the Coil can be applied to move the plunger electromagnetically. As a rule, the tappet and the coil are arranged in a metallic casing, via which a magnetic circuit can be closed, so that a magnetic flux is possible starting from the coil via the core, the armature plate and the casing with low magnetic resistance.

Usually, in the case of an actuating device with a plurality of actuator units, preferably each plunger is mounted in the actuating device so that it can rotate freely about the longitudinal axis. This minimizes wear on the tappets, especially since these can roll off on sleeves with which the tappets interact during camshaft adjustment.

It has proven that a permanent magnet and an armature element are arranged on the plunger, preferably on each ram in the case of an actuating device with several actuator units, with the armature element protruding beyond the permanent magnet in a plane perpendicular to a longitudinal axis of the actuator unit. A magnetic circuit can then be closed with a particularly low magnetic resistance from the coil via the armature element and a casing, so that the plungers can be actuated efficiently via the coils.

Advantageously, in the case of an actuating device with a plurality of actuator units, each plunger is connected directly or indirectly via a spring to the coil associated with the plunger. In this way, in conjunction with the permanent magnet, a force balance of magnetic force and spring force can be achieved, with a resultant force or total force being able to be influenced with little effort by additional energization of the coil or a direction of the total force being reversible by energizing the coil in order to move the actuator unit to operate. The coil can be designed, for example, so that when a predefined voltage is applied, in particular a voltage from an operating voltage of, for example, 12 volts that is available in a motor vehicle, a corresponding magnetic field results. The spring can be supported, for example, on the core or on a yoke disc arranged behind the core. Furthermore, a spring can be used to reduce the speed of the ram during a movement counter to the lifting direction, before the ram strikes a stop on the core side. This reduces wear on the stop. This is particularly favorable when the stop is formed by a core made of a soft, easily magnetizable material and a contact surface between the tappet and the core is small, in order to prevent the tappet from sticking to the core, in particular due to an oil film on the contact surface . Thus, by using the spring between the plunger and the core, a stop device made of a hard material can be dispensed with, as a result of which a particularly simple structure is ensured.

Furthermore, when using a spring between the plunger and the coil, a particularly favorable progression of a force acting on the plunger can be achieved over a stroke, so that an armature element, in particular one arranged on the plunger magnetically conductive armature plate, is not required to move the ram between the end positions with a simultaneous low energy input.

It is favorable if the spring, the armature element, the permanent magnet and the coil are designed and coordinated with one another in such a way that when the coil is de-energized, there is a total force of spring force and magnetic force which, starting at a predefined minimum distance from an end position close to the core, especially when the distance of the ram from the end position close to the core is less than 1 mm, into the end position close to the core. This ensures in a simple manner a stable position of the ram in the end position close to the core when the coil is de-energized.

It is preferably provided that the spring, the armature element, the permanent magnet and the coil are designed and coordinated with one another in such a way that when the coil is energized, a total force of spring force and magnetic force results, which moves the plunger located in an end position close to the core into an end position remote from the core . By energizing the coil, a total force acting on the armature element or the plunger from the spring force, the force of the permanent magnet and the magnetic force on the plunger resulting from the magnetic flux through which the coil is energized can be achieved, which pushes the plunger away from the end position close to the core to actuate the actuator or adjustment device. As a rule, the spring force acts on the plunger in the end position near the core in a lifting direction, which points from the end position near the core to the end position far from the core, while the force of the permanent magnet usually pulls the plunger near the end position near the core into the end position near the core and thus counter to the end position Stroke direction is aligned. The magnetic force on the armature element that results from the magnetic flux through the coil when it is energized is generally also aligned in the stroke direction.

The adjusting device is usually designed in such a way that the plunger is moved away from the end position near the core by means of the spring and the force caused by the magnetic flux on the anchor element until the plunger is pulled by the permanent magnet into an end position remote from the core. As a rule, the plunger can be pulled by the permanent magnet from a distance of less than 1 mm from the end position away from the core to the end position away from the core. are preferred Both in the end position close to the core and in the end position remote from the core, magnetizable devices or devices cooperating with the permanent magnet are arranged, so that the plunger is pulled into the respective end position by the permanent magnet located in a region close to the respective end position.

Advantageously, it is provided that the spring, the armature element, the permanent magnet and the coil are designed and matched to one another in such a way that a plunger located in an end position remote from the core remains in the end position remote from the core independently of an energization of the coil and only by an additional, in particular a form-fitting force applied to the ram, can be moved out of the end position remote from the core.

The plunger preferably adheres by means of the permanent magnet in the end position remote from the core, usually on a metallic component, in particular a plate. Moving the ram back from the end position remote from the core is therefore only possible by actively moving the ram, which can be done, for example, by a sleeve on a camshaft that has a cam track. As a result, a bistable adjusting device is achieved in a simple manner, which is stable in a currentless state of the coil both in the end position near the core and in the end position remote from the core. The sleeves with which the tappets in camshaft adjusting devices interact usually have a groove with a variable depth over a circumference that follows a cam track, so that the tappet can be moved back from the end position remote from the core by rotating the sleeve or rotating the camshaft.

It has been proven that a stop device, in particular an approximately hemispherical stop device at the end, preferably a ball or a pin, is provided on at least one actuator unit, preferably on each actuator unit in the case of an actuating device with several actuator units, so that the plunger assigned to the respective actuator unit in an end position close to the core rests against the stop device. An end position of the ram close to the core can be defined in a simple manner with high accuracy by means of a stop formed in this way close to the core.

The plunger is usually designed at one end on the core side in such a way that contact with the stop device results in a punctiform contact surface. For example, the ram can have a flat spot on one end on the core side or a contact surface can run perpendicularly to a longitudinal axis of the ram, so that the contact surface is designed as a circular disk, for example, if the ram has a cylindrical shape. An end position of the plunger can be defined particularly easily and at the same time with high accuracy by means of a punctiform contact surface, which then results when there is contact with a ball or a pin that is approximately hemispherically formed at the end. Corresponding balls and pins are mass-produced and therefore available at low cost and with high quality.

In principle, the stop device can be connected to the core in any manner, in particular rigidly, for example pressed into the core or fixed in a component rigidly connected to the core, in particular a yoke disk. In order to minimize wear, however, the stop device can also be connected directly or indirectly to the coil of the respective actuator unit via a spring. An indirect connection can be made, for example, by the stop device being connected via the spring to a yoke disk which is arranged at an end of the core opposite a ram-side end of the core and is rigidly connected to the core and thus also to the coil. Furthermore, the spring can be connected to a core assigned to the respective actuator unit or to a component rigidly connected to the core, such as the yoke disk. In this embodiment, when moving from the end position remote from the core, the ram first contacts the stop device connected to the core via the spring, after which the stop device is moved along with the ram until the stop device is on the core or on a particularly hits a component rigidly connected to the core, preferably on a stop plate arranged in the core or on a yoke disk connected to the core.

It is favorable if the stop device is in contact with a yoke disk connected to a core of the actuator unit, in particular if it is fixed in the yoke disk. As a result, mechanical stress on the core can be minimized in a simple manner. Usually, the yoke disk, on which the stop device rests, is arranged on a back side of the core, which is a front side of the core on which the Plunger is positioned and which can also be referred to as the ram-side end of the core, opposite.

It is preferably provided that the stop device is arranged in a through hole arranged in the core and preferably protrudes beyond the core on both sides along a longitudinal axis. If the stop device is supported on a component that is rigidly connected to the core and the coil, such as the yoke disk, which is arranged on the opposite side of the core to the plunger in the direction of the longitudinal axis, a mechanical load on the core can occur when the plunger hits the Stop device can be avoided entirely, so that a particularly long service life is achieved. In order to allow contact between the ram and the stop device, the core then usually has a through hole into which the stop device and/or the ram protrude when the ram is in an end position close to the core. To minimize the moving masses, it is favorable if the stop device, which is usually rigidly connected to the coil, is arranged entirely in the through hole in the core and protrudes through the core, but without the core being connected to the stop device in such a way that forces are transmitted in the direction of the longitudinal axis between the stop device and the core, so that the stop device protrudes beyond the core on both sides in the direction of the longitudinal axis. Surprisingly, it has been shown that when a through hole is made in the core, the service life of the device can be increased because the stop device is then no longer supported on the core, which is usually made of a soft material, but on a component arranged behind the core can, whereby the core is not stressed.

In order to be able to ensure a highly precise end position of the ram even after a longer period of use, it is preferably provided that the stop device has a higher hardness than a core assigned to the actuator unit. The core generally has favorable magnetic properties in order to obtain the lowest possible resistance of a magnetic circuit, by means of which the plunger can be actuated by energizing the coil. The stop device, on the other hand, can consist of a material such as 100Cr6, for example.

According to the invention, a predefined ram movement is achieved in a simple manner by providing a ram guide assigned to each ram in an actuating device with a plurality of actuator units, in which the ram is slidably mounted. A total force on the tappet resulting from spring force and magnetic force causes a movement along the tappet guide, depending on the direction of the total force. The plunger guide is preferably formed from a metal. In the case of an actuating device with a plurality of actuator units, it can be provided that a plurality of tappet guides are arranged in a common component and are formed, for example, by cylindrical bores in a guide body.

According to the invention, at least two actuator units are provided and each ram is slidably mounted in a separate ram guide, with the ram guides being movable relative to one another. This enables a particularly simple connection to a device on which the actuating device acts, in particular to a motor, especially since positional tolerances at a mechanical interface to the device, in particular at locating bores on the motor in which the tappets engage, are compensated for by the mobility of the tappet guides relative to one another can become. The tappet guides are preferably also movable relative to the coils or the housing, in which housing the coils are arranged. It goes without saying that a minimal mobility of a few degrees or a few millimeters can be sufficient here to compensate for positional tolerances.

Structurally, this can be achieved, for example, when there is a plurality of tappets for each tappet guide and the tappet guides are arranged in separate guide bodies, the guide bodies being movable relative to one another. This can be implemented, for example, in that the separate guide bodies are movably connected to the housing or to a component of the actuating device that is rigidly connected to the coil. A correspondingly movable connection of the tappet guides to the housing can be achieved in a simple manner, for example, by means of a guide body connected to the housing or to a component rigidly connected to the housing by means of a clearance fit.

The tappet guide can be formed in the guide body, for example, by a through hole. This is a particularly simple cultivation of Adjusting device on an engine or a cylinder head cover of an engine is possible, especially since deviations in the engine and/or in the adjusting device can then be easily compensated for by the low mobility of the guide body relative to the housing due to the loose fit. The guide bodies can then be designed, for example, as turned parts, which can be produced easily and inexpensively. Such an embodiment also makes the adjusting device easily scalable. Thus, with corresponding guide bodies, adjusting devices with any number of actuator units can then be produced in a simple manner, while at the same time positional deviations of mounting bores on a motor can be compensated for.

The adjusting device is usually attached to a cylinder head cover of an internal combustion engine and the tappets engage in correspondingly provided recesses or bores in the cylinder head cover or in the engine, through which recesses or bores the tappets interact with the sleeves arranged on the camshaft. A simple possibility of compensating for tolerances between the recesses or bores is thus provided by means of plunger guides arranged in separate guide bodies.

The rams are usually designed with an approximately cylindrical outer contour. Corresponding to this outer contour, the guides are preferably also formed approximately cylindrically and the guides have a diameter which corresponds to a maximum diameter of the ram.

In order to achieve particularly low wear, it is advantageous if the rams have a central taper which is positioned in the ram guide for every possible ram position between an end position of the ram near the core and an end position of the ram remote from the core. The adjusting device is usually arranged on a camshaft in an engine, and thus in an oil mist. Oil can then accumulate around the taper, which ensures good lubrication of a contact surface between the tappets and the guide.

A particularly inexpensive construction can be achieved when a coil arranged in the core has an approximately cylindrical outer contour, with a maximum Outside diameter of the core is less than or equal to an inside diameter of the coil. The core therefore preferably has no shoulder or the like on the outside, so that it can be manufactured easily, for example from a cylindrical starting material.

In order to achieve a high level of efficiency, it is advantageous if a preferably plate-shaped component made of a magnetically conductive material, in particular a yoke disk, is arranged and connected to the core at one end of the core on the ram side and/or at an end of the core opposite the ram end. which component protrudes beyond the core in a direction radial to the longitudinal axis. As a result, a low magnetic resistance between the core and the jacket can be achieved despite a core that can be produced inexpensively and has a cylindrical outer contour that does not protrude beyond an inner diameter of the coil. The magnetic circuit can then be formed in a cost-effective manner, for example, from the core, the yoke disks arranged at both ends of the core and the jacket, as well as the magnetically conductive parts of the plunger. The yoke disks are generally annular and made of an easily magnetizable plate material, with a material of the yoke disks generally differing from a material from which the core is formed. With such an embodiment in which the core and the two yoke disks are formed by separate components, manufacturing costs can be reduced compared with an embodiment in which the core and the yoke disks are formed by a single component.

The adjusting device according to the invention can in principle be used for any purpose. The advantages of the adjusting device according to the invention can be used particularly well if it is used in a camshaft adjusting device for adjusting an axially movable sleeve on a camshaft in an internal combustion engine with an electromagnetic adjusting device.

• Fig. 1 eine erfindungsgemäße Stellvorrichtung in Schnittdarstellung;
• Fig. 2 ein Diagramm, welchem auf einen Stößel wirkende Kräfte über einen Hub entnehmbar sind;
• Fig. 3 und 4 weitere Ausführungsformen einer erfindungsgemäßen Stellvorrichtung in Schnittdarstellung.

Further features, advantages and effects of the invention result from the exemplary embodiment presented below. The drawings to which reference is made show:

• 1 an adjusting device according to the invention in a sectional view;
• 2 a diagram showing forces acting on a ram over a stroke;
• 3 and 4 further embodiments of an adjusting device according to the invention in a sectional view.

1 shows a sectional view of an actuating device 1 according to the invention. As can be seen, in the exemplary embodiment shown, two actuator units are provided in a common housing 4, each actuator unit having a coil 2, a core 7 around which the coil 2 is arranged, a plunger extending along a longitudinal axis 17 3, a spring 10 which connects the plunger 3 to the core 7, a permanent magnet 6 and an armature element formed by an armature plate 9.

A magnetic circuit, via which the plunger 3 can be actuated by means of the coil 2 , is closed via a jacket 15 in which the coil 2 is arranged and via which the coil 2 is magnetically connected to the armature element on the plunger 3 .

As shown, it is favorable to ensure a small distance between the tappets 3 if the jacket 15 is arranged to enclose both cores 7, but no jacket 15 is positioned between the cores 7.

As can also be seen, the tappets 3 are each arranged coaxially to the longitudinal axes 17 of the coils 2 or centrally to the coils 2 . Longitudinal axes 17 of the rams 3 thus coincide with longitudinal axes 17 of the rams 3 . As a result, no moment about an axis transverse to the longitudinal axis 17 acts on the plunger 3 when it is actuated by means of a magnetic force caused by the coils 2, which is why the plunger guide 12 can be of particularly simple design.

In order to be able to produce the actuating device 1 particularly inexpensively, the core 7 arranged in the coil 2 has an essentially cylindrical outer contour, with a maximum outer diameter 28 of the core 7 approximately corresponding to a minimum inner diameter of the coil 2 . It goes without saying that the coil 2 is understood here not only as the windings themselves, but also as a component carrying the windings, which is located between the core 7 and the windings themselves.

In order to still achieve a low magnetic resistance between the core 7 and the jacket 15, yoke disks 27 are arranged both on one end of the core 7 on the ram side and on an end of the core 7 opposite the ram end, which yoke disks 27 connect the core 7 radially to the longitudinal axis 17 tower over and thus produce a magnetic connection between the core 7 and the jacket 15. The yoke disks 27 are made of an easily magnetizable plate material and have an approximately circular cross-section in a section perpendicular to the longitudinal axis 17 .

The armature plate 9 protrudes on each ram 3 in a plane perpendicular to the longitudinal axis 17 or perpendicular to the plane of the drawing beyond the permanent magnets 6 of the respective ram 3 , so that a magnetic circuit can be closed via the armature plate 9 . The permanent magnets 6 are only separated from the core 7 by an air gap 8 . An approximately hollow-cylindrical protective sleeve 13 is arranged around each permanent magnet 6 . A magnetic flux caused by the coil 2 and the magnetic circuit thus runs essentially through the core 7, the plunger 3, the armature plate 9 and the jacket 15.

As a result, a force can be applied to the armature element or the respective plunger 3 by energizing the coil 2, which force moves the plunger 3 away from the end position 23 close to the core.

From the two in 1 actuator units shown, the ram 3 of the actuator unit shown on the left is in an end position 23 close to the core and the ram 3 of the one on the right in 1 illustrated actuator unit in an end position 24 remote from the core. In the end position 23 close to the core, the ram 3 rests against a stop device designed as a ball 5, which ball 5 is in turn positioned in the core 7, so that the end position 23 of the ram 3 close to the core is simple and highly precise at the same time is defined. The tappets 3 make contact with the ball 5 on an essentially flat contact surface 16 in the shape of a circular disk, so that there is point-like contact. In order to be able to ensure the exact position of the end position 23 close to the core over a long period of time or a desired service life of a motor in which the actuating device 1 is used, the stop device is made of a material with high hardness or a higher hardness than the core 7 .

The rams 3 are guided in ram guides 12 , which ram guides 12 are formed by cylindrical bores in a guide body 18 . The rams 3 also have a cylindrical outer contour in some areas, which interacts with the ram guides 12, so that the rams 3 can only be moved translationally in the direction of the longitudinal axis 17 and can be rotated about the longitudinal axis 17, but beyond that no movement of the rams 3 relative to the housing 4 or to the guide body 18 is possible.

As can also be seen, the tappets 3 in the tappet guides 12 have tapers 14 in which oil can collect in order to lubricate a movement of the tappets 3 in the guides and thus minimize wear.

The plungers 3 are connected to the core 7 via the spring 10 and the permanent magnet 6 in such a way that the spring 10 exerts a force on the plunger 3 in a lifting direction 25, i.e. from the end position 23 near the core in the direction of the end position 24 remote from the core, parallel to the Longitudinal axes 17, is exercised when the plunger 3 are in the end position 23 close to the core. In the end position 23 close to the core, the permanent magnets 6 apply a force that counteracts the spring force 20 to the plunger 3 and is greater in magnitude than the spring force 20, so that the plunger 3 is subjected to a total force of magnetic force and spring force 20 in a currentless state of the coil 2 be held in the end position 23 close to the core. When the coil 2 is de-energized, the total force acts in the opposite direction to the stroke direction 25.

In order to actuate an actuator unit and to move the corresponding plunger 3 from the end position 23 close to the core, an electrical voltage is applied to the coil 2 of this actuator unit, causing a magnetic flux in the magnetic field formed by the core 7, casing 15, plunger 3 and anchor plate 9 Circle causes a force on the ram 3 in the lifting direction 25 so that the total force acting on the ram 3 points in the lifting direction 25 and the ram 3 is moved out of the end position 23 close to the core.

With the corresponding actuation, the ram 3 is moved into the end position 24 remote from the core, in which the ram 3 bears against a stop formed by a metal plate 11 .

Longitudinal axes 17 of the two tappets 3 are, as shown, approximately parallel and, when using the actuating device 1, are usually spaced apart by less than 25 mm, in particular 6 mm to 15 mm. With the design of the adjusting device 1 according to the invention, a force sufficient for camshaft adjustment can be provided despite the small distance.

2 shows schematically the forces acting on a ram 3 of an actuator unit as a function of a stroke of the ram 3 starting from the end position 23 near the core in the stroke direction 25 to an end position 24 of the ram 3 remote from the core.

Both a magnetic force are shown, i.e. a magnetic force on the plunger 3 resulting from the force of the permanent magnet 6 and a magnetic force caused by the energization of the coil 2, as well as a spring force 20 resulting from the spring 10, the magnetic force in a solid line for one situation is shown in which the coil 2 is not energized and in broken line for a situation in which the coils 2 is energized. The solid line thus represents a currentless magnetic force 21, which is caused by the permanent magnet 6 alone, and the broken line represents the energized magnetic force 22, which is a total force from the force of the permanent magnet 6 and the magnetic force caused by the energization of the coil 2 on the Plunger 3 forms. In the case of the spring force 20 , a force in the lifting direction 25 is shown as the positive force, while in the case of the currentless magnetic force 21 and the energized magnetic force 22 , positively illustrated forces are aligned counter to the lifting direction 25 . The ordinate of the diagram thus shows values in the lifting direction 25 with regard to the spring force 20 and values opposite to the lifting direction 25 with regard to the magnetic forces.

As can be seen, a de-energized magnetic force 21 holding the plunger 3 in the end position 23 close to the core, ie at a stroke of 0 mm, is greater than the spring force 20 at this stroke. When the coil 2 is de-energized, the plunger 3 is held by the permanent magnet 6 in the end position 23 close to the core. As shown, the spring force 20 decreases over the stroke and approaches zero in the end position 24 of the plunger 3 remote from the core. This ensures that when the plunger 3 moves, the spring 10 is never without a defined position between the core 7 and the plunger 3 or is loose, which could lead to noise and wear.

If the coil 2 is energized, the magnetic force holding the plunger 3 in the end position 23 close to the core is reduced below the magnitude of the spring force 20, so that the de-energized magnetic force 21 acts, whereby the plunger 3 moves out of the end position close to the core when the coil 2 is energized by means of the spring force 20 23 is moved.

As can also be seen, the ram 3 is pulled close to an end position 24 remote from the core into the end position 24 remote from the core. This is done by a magnetic force caused by the permanent magnet 6, by which the ram 3 is pulled to a plate 11 forming a stop in the end position 24 remote from the core.

The plunger 3 is thus positionally stable both in the end position 23 close to the core and in the end position 24 remote from the core when the coil 2 is in a de-energized state. In order to move the ram 3 from the end position 24 remote from the core back to the end position 23 close to the core, the ram 3 is moved counter to the lifting direction 25 at least up to a minimum return position 19, for example by means of a sleeve, into which the ram 3 engages in a camshaft adjustment device . From this minimum return position 19, the magnetic force of the permanent magnet 6 that pulls the plunger 3 into the end position 23 close to the core when the coil 2 is de-energized, i.e. the de-energized magnetic force 21 against the lifting direction 25, is greater than the spring force 20 in the lifting direction 25, so that a resultant force acts against the lifting direction 25 on the ram 3 and the ram 3 is pulled from the minimum return position 19 into the end position 23 close to the core when the coil 2 is de-energized.

3 shows another adjusting device 1 according to the invention, which is basically similar to that in 1 The adjusting device 1 shown is constructed, but in contrast to that in 1 Actuating device 1 shown has a pin 26 as a stop device. As shown, the stop device designed as a pin 26 is supported here on a yoke disk 27 arranged behind the core 7 or on a rear side of the core 7 opposite a ram-side end of the core 7, so that the core 7 is not mechanically stressed when the ram 3 strikes becomes. In order to be able to transmit a force from the ram 3 to the yoke disk 27 when the ram 3 hits, without mechanically stressing the core 7, a through hole is provided in the core 7 in this embodiment. In the illustrated embodiment, the pin 26 is positioned in the through hole and protrudes from both sides of the core 7 without however, to touch the core 7 or a yoke disk 27 arranged on a ram-side end of the core 7 in a manner suitable for the transmission of forces in the direction of the longitudinal axis 17 . Furthermore, a spring 10 is also provided in this embodiment, which is also supported here on the yoke disk 27 and passes through the through hole in the core. Alternatively, the spring 10 could of course also be supported on the core 7, for example on a shoulder in the through hole in the core 7. This design increases the service life because the core 7 is not mechanically stressed every time the plunger 3 hits. The through hole can lead to a magnetic weakening 7 of the core 7 or to an increased magnetic resistance of the core 7, which is accepted in order to minimize the mechanical stress.

4 shows a further adjusting device 1 according to the invention, which is largely analogous to that in 3 shown is constructed. Deviating from the in 3 In the adjusting device 1 shown, the tappet guides 12 are arranged here in separate guide bodies 18 which are connected to the housing 4 via the plate 11 . The guide bodies 18 are connected to the plate 11 with little mobility or with play, so that the actuating device 1 can be easily connected to a connecting component of an engine, usually a cylinder head cover, even if manufacturing tolerances both in the engine as well as in the actuating device 1 are used in the most unfavorable way or a mechanical interface on the motor has positional and/or positional deviations. Thus, the guide bodies 18 and thus an alignment of the longitudinal axes 17 of the plungers 3 can easily be adapted to corresponding circumstances by the movable connection of the guide bodies 18 to the housing 4 or to the plate 11 . It goes without saying that the guide bodies 18 can then also be moved relative to one another and that the longitudinal axes 17 of the plungers 3 may no longer be exactly parallel.

With an adjusting device 1 according to the invention, a bistable adjusting device 1 for camshaft adjustment is achieved in a particularly simple manner, which ensures a particularly simple and therefore cost-effective guidance of the tappets 3 .

Claims (15)

1. An electromagnetic actuating device (1) with at least two electromagnetic actuator units, wherein each actuator unit has a coil (2) and a plunger (3), which plunger (3) is movable axially relative to the coil (2) via an energization of the coil (2), wherein the actuator unit is arranged in a housing (4), wherein the plunger (3) is arranged approximately coaxially with the coil (2), wherein a plunger guide (12) associated with the plunger (3) is provided, in which plunger guide (12) the plunger (3) is mounted in a sliding manner, characterized in that each plunger (3) is mounted in a sliding manner in a separate plunger guide (12) and the plunger guides (12) are movable relative to one another.
2. The electromagnetic actuating device (1) according to claim 1, characterized in that the plungers (3) are arranged approximately coaxially with the coils (2) in all actuator units, wherein all actuator units are preferably arranged in a common housing (4).
3. The electromagnetic actuating device (1) according to claim 1 or 2; characterized in that a permanent magnet (6) is arranged on the plunger (3), wherein it is preferably provided that the coil (2) is arranged around a core (7), wherein the permanent magnet (6) is only separated magnetically from the core (7) in an axial direction by an air gap (8).
4. The electromagnetic actuating device (1) according to claims 1 to 3, characterized in that an armature element, in particular an armature plate (9), is arranged on the plunger (3).
5. The electromagnetic actuating device (1) according to claim 1 or 2, characterized in that a permanent magnet (6) and an armature element are arranged on the plunger (3), wherein the armature element protrudes beyond the permanent magnet (6) in a plane perpendicular to a longitudinal axis (17) of the actuator unit, wherein it is preferably provided that the plunger (3) is connected indirectly or directly to the coil (2) associated with the plunger (3) via a spring (10).
6. The electromagnetic actuating device (1) according to claim 5, characterized in that the spring (10), the armature element, the permanent magnet (6) and the coil (2) are configured and coordinated such that, when the coil (2) is in a de-energized state, a cumulative force consisting of spring force (20) and magnetic force results, which pulls the plunger (3) from a predefined minimum distance of an end position (23) close to the core, in particular when the distance of the plunger (3) from the end position (23) close to the core is less than 1 mm, into the end position (23) close to the core.
7. The electromagnetic actuating device (1) according to claim 5 or 6, characterized in that the spring (10), the armature element, the permanent magnet (6) and the coil (2) are configured and coordinated such that, when the coil (2) is energized, a cumulative force consisting of spring force (20) and magnetic force results, which moves the plunger (3) in an end position (23) close to the core into an end position (24) away from the core.
8. The electromagnetic actuating device (1) according to one of claims 5 to 7, characterized in that the spring (10), the armature element, the permanent magnet (6) and the coil (2) are configured and coordinated such that a plunger (3) in an end position (24) away from the core remains in the end position (24) away from the core independently of an energization of the coil (2) and can only be moved out of the end position (24) away from the core by an additional force applied, in particular in an interlocking manner, to the plunger (3) .
9. The electromagnetic actuating device (1) according to one of claims 1 to 8, characterized in that a stop device, in particular a stop device that is roughly hemispherical at one end, preferably a ball (5) or a pin (26), is provided on each actuator unit so that the plunger (3) associated with the actuator unit rests against the stop device in an end position (23) close to the core.
10. The electromagnetic actuating device (1) according to claim 8, characterized in that the stop device is connected indirectly or directly to the coil (2) of the respective actuator unit via a spring (10), wherein it is in particular provided that the stop device rests against a yoke plate (27) connected to a core (7) of the actuator unit and is in particular fixed in the yoke plate (27).
11. The electromagnetic actuating device (1) according to one of claims 1 to 10, characterized in that the plunger guides (12) are arranged in separate guide bodies, wherein the guide bodies are movable relative to one another.
12. The electromagnetic actuating device (1) according to one of the claims 1 to 11, characterized in that the plungers (3) exhibit a central taper (14), which is positioned in the plunger guide (12) at every possible plunger position between an end position (23) of the plunger (3) close to the core and an end position (24) of the plunger (3) away from the core.
13. The electromagnetic actuating device (1) according to one of claims 1 to 12, characterized in that a core (7) with a cylindrical outer contour is arranged in each coil (2), wherein a maximum outer diameter (28) of the core (7) is smaller than or equal to an inner diameter of the coil (2).
14. The electromagnetic actuating device (1) according to claim 13, characterized in that a preferably plate-shaped component made of a magnetically conductive material, in particular a yoke plate (27), is arranged at a plunger-side end of the core (7) and/or at an end of the core (7) opposite the plunger-side end and is connected to the core (7), which component projects beyond the core (7) in a radial direction relative to the longitudinal axis (17).
15. A camshaft adjustment device for adjusting an axially movable sleeve on a camshaft in an internal combustion engine with an electromagnetic actuating device (1), characterized in that the electromagnetic actuating device (1) is configured according to one of claims 1 to 14.

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