DE102016203063A1 - Reluctance actuator for active bearings with reduced power consumption - Google Patents

Abstract

Reluctance actuator (1), comprising at least one ferromagnetic stator (2, 2a, 2b), at least one exciting coil (3, 3a, 3b) for introducing a magnetic, chained flux Ψ into the stator (2, 2a, 2b) and at least one active element ( 4), which is movably mounted against the stator (2, 2a, 2b), the inductance L of the excitation coil (3, 3a, 3b) interacting with the stator (2, 2a, 2b) from the position p of the active element (4 ), wherein the stator (2, 2a, 2b) has at least one gap (5, 5a, 5b) into which a ferromagnetic region (41, 41a, 41b) of the active element (4) can be inserted.
Active bearing (100) which compensates an attacking bearing force F _L at least partially by applying a counterforce F _G , wherein the reluctance actuator (1) is provided for the application of the counterforce F _G.

Description

The present invention relates to a reluctance actuator for active bearings, in particular for engine mounts in a motor vehicle.

State of the art

Active engine mounts are part of various cars and reduce the vibration transmission of the internal combustion engine to the chassis. Among other things, this reduces the development and transmission of noise. Active engine mounts are for example from the DE 10 2011 081 291 A1 known.

For example, hydraulic bearings are used as the basis for an active engine mount. In this case, an attacking bearing force F _{L is} transmitted to a hydraulic fluid in a hydraulic chamber, and a counterforce F _G for compensating for these bearing forces is introduced by the pressure of the hydraulic fluid is changed via an actuator. Hydraulic bearings as active engine mounts are for example from the DE 10 2011 011 328 A1 known.

As Aktorprinzipien reluctance, Lorentz and piezo actuators and hybrid solutions, such as Lorentz reluctance actuators known. The actuators are controlled via an external control unit that is separate from the engine control unit.

The DE 196 34 342 A1 describes general state of the art for controlling electromagnetic consumers. The DE 10 2014 204 165 A1 and the DE 10 2014 204 286 A1 describe general state of the art for the production of actuators or stators for electric motors.

Disclosure of the invention

Within the scope of the invention, a reluctance actuator has been developed. This reluctance actuator comprises at least one ferromagnetic stator, at least one excitation coil for introducing a magnetic flux Φ, or a magnetic chained flux Ψ, into the stator and at least one active element which is movably mounted against the stator. The inductance L of the excitation coil cooperating with the stator is strongly saturated in regions and thus not only dependent on the position p of the active element, but also on the current I through the exciter coil.

When the exciter coil is energized, a force acts on the active element, which endeavors to maximize the inductance L. With a single reluctance actuator, the active element can be converted into this position p _M by energizing the exciter coil from a certain catchment area of positions p around the position p _M in which the inductance L is maximum. The active element may alternatively or in combination thereto by energizing the excitation coil in one direction to the position p _M moves to and moved in the other direction by a restoring force, such as a spring force, away from this position. The active element may for example be movably mounted in a way that it is linearly movable in one dimension.

The excitation coil can be energized, for example, via a voltage source and at least one control element connected in series with the excitation coil.

According to the invention, the stator has at least one gap into which a ferromagnetic region of the active element can be inserted.

It has been recognized that the inductance L of the excitation coil cooperating with the stator is very much dependent on whether the ferromagnetic region of the active element is inserted into the gap or not. Accordingly, a reluctance force acts on the ferromagnetic region of the active element, which endeavors to introduce this region into the gap and thus to maximize the inductance L.

In this case, the combination of the gap with the ferromagnetic region of the active element inevitably entails that after insertion of the ferromagnetic region into the gap on both sides of the ferromagnetic region in each case a part of the gap remains free. The ferromagnetic region of the active element is thus separated on two sides by an air gap from the stator. Each of these two air gaps represents a resistance for the magnetic chained flux.. Compared to the prior art, in which there was only one air gap between the stator and the active element, the resistance for the magnetic interlinked flux Ψ is thus approximately doubled. Accordingly, the inductance L, and thus also the achievable reluctance force, are approximately halved.

However, it was recognized that in return the active element can be built much easier. Especially when in an active camp, in which the reluctance is provided for exerting the counterforce F _G , the counterforce F _G quickly tracked a change in the attacking bearing force F _L , it ultimately depends on how fast the active element can be accelerated. Since only a small proportion of the active element must be designed as a ferromagnetic region and the remainder can be made of a lightweight material, the weight of the active element can be reduced by up to 70%. Accordingly, less reluctance force is required for the same acceleration, and so much less that even the current I through the exciter coil can be reduced. As a result, the control of the reluctance, and thus the active bearing as a whole, requires a much lower current. This lower current level, in turn, can be provided by the already existing engine control unit when using the active bearing as an engine mount in a vehicle.

Ultimately, therefore, provided according to the invention gap on the stator has the effect that an active engine mount with the reluctance of the existing engine control unit can be controlled and an additional control device is only necessary for the control of the active engine mount.

The apparent disadvantage of a reluctance force initially reduced by the double air gap is thus clearly overcompensated.

In this context, the reduced power requirement continues to have the advantageous effect that the components for driving the reluctance factor for smaller maximum currents can be dimensioned. Accordingly, smaller components can be used for this, so that the integration of the control for the active engine mount in the existing engine control unit requires less additional space. It again has an advantageous effect here that the inductance L of the exciting coil cooperating with the stator is reduced overall by the double air gap.

The lighter version of the active element further has the effect that the mechanical natural frequency of the active element, and thus also an active bearing with this active element, is increased. Especially when using the reluctance actuator in an active engine mount, it is important that the motor bearings can absorb the unwanted vibrations particularly well in the frequency range in which the frequency spectrum of the attacking bearing force F _{L has} the largest shares. In this context, the double air gap on both sides of the inserted into the gap on the stator ferromagnetic region of the active element, which initially caused an apparent disadvantage, be converted to another advantage: The width of this air gap is another degree of freedom, with the Natural frequency of the active bearing can be acted upon. In particular, the bandwidth of frequencies f of the applied bearing force F _L that can be absorbed by the active bearing can be increased by the double air gap.

The elimination of an additional control unit alone for the active engine storage saves space, material costs and overhead for additional wiring. Furthermore, it is generally favorable from the point of view of vehicle manufacturers to manage with as few control devices as possible. Finally, the energy savings in the active engine mounts also have a favorable effect on fuel consumption and thus on CO ₂ emissions.

A reluctance actuator in an active bearing generally has the advantage that it manages without permanent magnets, which are usually made of rare earths and cause correspondingly high material costs. Furthermore, amplitude and frequency of the force applied by the reluctance actuator counterforce F _{G are} separated from each other adjustable.

In particular, the gap may represent a complete disruption of a structure of the stator through which at least a portion of the magnetic chained flux Ψ introduced into the stator by the exciter coil is guided. The inductance L of the excitation coil cooperating with the stator then reacts with maximum contrast on whether or not the ferromagnetic region of the active element is introduced into the gap. On the other hand, if the gap is not a complete break, at least a portion of the magnetic chained flux Ψ concentrates on the structure bridging it.

Advantageously, the gap corresponds to the ferromagnetic region of the active element. This may in particular mean that the gap is filled as best as possible from the inserted ferromagnetic region of the active element up to the double air gap and / or that the ferromagnetic region of the active element is wholly insertable into the gap. Among other things, if the gap corresponds to the ferromagnetic region of the active element, this can also have the effect that there is exactly one position p _M for the position p of the active element in which the inductance L of the exciter coil cooperating with the stator is maximal. When energized excitation coil, the active element then has a defined stable rest position, without the need for a mechanical stop is required.

In addition to the ferromagnetic region, the active element advantageously comprises a non-ferromagnetic carrier, which may in particular have at least ten times the volume of the ferromagnetic region. The weight savings of the active element is then particularly pronounced.

In a particularly advantageous embodiment of the invention, the stator is composed of at least a first piece and a second piece, and the exciting coil is wound on one of the two pieces. The coil can then be particularly easy before final assembly of the Reluctance actuator with high filling factor to be wound separately. In particular, a high fill factor can be achieved with a winding of the exciter coil, which is concentric with an axis of symmetry of the reluctance actuator. To achieve a high filling factor, the winding is advantageously carried out with profile wire.

The two pieces do not have to be made of the same material. They can also consist of different materials. Each of the pieces may for example also be a laminated core of parallel, ferromagnetic, mutually insulated sheets.

Advantageously, the stator is at least partially made of a soft magnetic composite material, SMC. This composite material may comprise, for example, an electrically insulating matrix in which magnetic particles are embedded. The formation of eddy currents with corresponding ohmic losses in the stator is then largely suppressed, since in the stator essentially only a capacitive current transport between the individual magnetic particles is possible.

In a further advantageous embodiment of the invention, the stator comprises at least two mutually adjacent laminated cores of parallel, ferromagnetic, mutually insulated sheets. The insulation between the sheets also suppresses the transport of eddy currents perpendicular to the planes of the sheets.

Advantageously, the interface between two adjacent laminated cores with the plane of at least one sheet from each of the two laminated cores forms an angle between 30 and 60 degrees, preferably between 40 and 50 degrees. The magnetic chained flux Ψ generated by the excitation coil can then pass particularly effectively from one laminated core to the next.

In a further particularly advantageous embodiment of the invention, the magnetic chained flux Ψ generated by the excitation coil is guided by a laminated core in the direction of the gap. The stronger the magnetic flux Φ, or the magnetic concatenated flux Ψ, is focused on the gap, the greater the reluctance force that pulls the ferromagnetic region of the active element into the gap.

In particular, a stator partially made of a soft magnetic composite material, SMC, can advantageously be supplemented with an additional laminated core, which guides the magnetic flux in the direction of the gap. A laminated core has a strong anisotropic resistance for a magnetic flux Φ. The resistance is smaller with a flow transport along the levels of the sheets than in SMC material, with a river transport perpendicularly to the levels of the sheets however clearly larger than in SMC material. Thus, if a magnetic flux Φ is to be guided around corners in a closed path, then on the one hand SMC material has the advantage that it can be easily converted by pressing into suitable geometric shapes. On the other hand, the flux transport resistance within the SMC material is isotropic because the individual magnetic particles are randomly oriented.

In a further particularly advantageous embodiment of the invention, at least two stators are provided with associated excitation coils and columns. The active element has at least two ferromagnetic regions, which are arranged relative to one another such that an increase in the inductance L of one exciter coil cooperating with the one stator reduces the inductance L of the other exciter coil cooperating with the other stator.

With this embodiment, it is particularly easy to implement a movement in two opposite directions, in that the two excitation coils are alternately energized. In contrast to a reluctance with only one excitation coil, a spring or other source for a restoring force, which undesirably predefines a mechanical natural frequency omitted.

In a further particularly advantageous embodiment of the invention, the active bearing is designed as a hydraulic bearing with a hydraulic chamber for receiving hydraulic fluid, wherein the hydraulic chamber between a receiving membrane for receiving the attacking bearing force F _L and coupled to the reluctance actuator actuator membrane for exerting the counterforce F _G extends. As a result, the frequency range in which the active bearing absorbs undesirable vibrations can advantageously be increased and at the same time the demand for electrical power can be further reduced. If, for example, the hydraulic chamber is connected to a secondary chamber via a throttled connection, friction losses during fluid transport, even without active electrical intervention, already result in damping in the bearing. This may already be sufficient to dampen the vibrations with frequencies f below the hydraulic natural frequency of the fluid column. The reluctance factor is then required only for higher frequencies f and consumes correspondingly less electrical energy.

A series connection of a control element and the excitation coil can be designed, for example, as an H-bridge of at least four control elements, between which the exciter coil is connected. For example, the H-bridge may be symmetric or asymmetric Be transistor bridge. The excitation coil can then be excited by two diagonally opposite controls in two different Spannungspolaritäten. This type of wiring of the exciting coil makes it possible to reverse the sign of the derivative of the magnetic chained flux Ψ introduced into the stator. Furthermore, it is possible to short-circuit the exciter coil and thus operate in the absence of energy storage in the capacitor as an electromagnetic brake. A movement of the active element by the outer bearing force F _L then generates a magnetic flux in the excitation coil, even without a permanent magnet on the remanent magnetization of the active element, which counteracts the movement according to the Lenz rule.

If several excitation coils are present, then each excitation coil can be supplied via a separate H-bridge from the same DC voltage source, for example, from the electrical system of a vehicle. The engine control unit, which contains the H-bridges, then generates, for example, rectangular actuation pulses, wherein the operating frequency, the amplitude and the pulse width factor can be regulated, for example, so that the counterforce F _{G of} the acting bearing force F _{L is} tracked in the best time possible.

Further measures improving the invention will be described in more detail below together with the description of the preferred embodiments of the invention with reference to figures.

embodiments

It shows:

1 Embodiment of an active bearing 100 with a reluctance factor 1 according to the invention;

2 Another embodiment of an active bearing 100 with smaller ferromagnetic areas 41a and 41b on the active element 4 ,

3 Partial perspective view of the area above the mounting plate 109 in 2 ,

4 Formation of a stator 2 from adjacent laminated cores 23a - 23d ,

1 shows an active hydraulic bearing 100 that's about an axis 100a is constructed rotationally symmetrical. In a housing 106 is a hydraulic chamber 101 for receiving hydraulic fluid 102 arranged. This hydraulic chamber is upwardly through the receiving membrane formed of an elastomer 103 and down through the actuator membrane 104 limited by a fortification 104a in the case 106 is held. The recording membrane 103 takes up the attacking bearing force F _L ; over the actuator membrane 104 the counterforce F _{G is} exercised. The recording membrane 103 is about the essentially incompressible hydraulic fluid 102 mechanically to the actuator membrane 104 coupled. The hydraulic chamber 101 is capable of hydraulic fluid via a restricted connection 102 to exchange with a secondary chamber and thus to dissipate the energy of low-frequency vibrations. However, this is not the subject of the present invention and therefore in 1 not shown for reasons of clarity.

The actuator membrane 104 is over a stamp 107 with a wave 105 connected in turn by the reluctance actuator 1 is movable. The Stamp 107 is in a first sliding bearing 108a along the axis of symmetry 100a movably mounted. The axis of the shaft 105 agrees with the symmetry axis 100a of the active warehouse 100 match. The wave 105 is in a second sliding bearing 108b along the axis of symmetry 100a movably mounted. The first plain bearing 108a is via a first flange 108c in the case 106 attached. The second plain bearing 108b is via a second flange 108d in the case 106 attached. The reluctance factor 1 extends in the housing 106 on both sides of a mounting plate 109 , in turn, with a fixing screw 109a is held.

Above the mounting plate 109 is a first stator 2a arranged, consisting of a first piece 21a and a second piece 22a is composed. On the second piece 22a is the first exciter coil 3a wound. The two pieces 21a and 22a of the first stator 2a limit a first circumferential gap 5a into which a first circumferential ferromagnetic region 41a of the active element 4 forming two air gaps 6a and 6b is insertable. The first exciter coil 3a is via a supply line 31a supplied with current.

Analog is below the mounting plate 109 a second stator 2 B arranged, consisting of a first piece 21b and a second piece 22b is composed. On the second piece 22a is the second exciter coil 3b wound. The two pieces 21b and 22b of the second stator 2 B limit a second circumferential gap 5b , in which a second circumferential ferromagnetic region 41b of the active element 4 forming two air gaps 6c and 6d is insertable. The second exciter coil 3b is via a supply line 31b supplied with current.

The active element 4 is at the shaft 105 attached. The ferromagnetic areas 41a and 41b of the active element 4 are arranged to each other so that only one of these areas 41a and 41b its associated gap 5a respectively. 5b Completely fill and so the inductance L of its associated excitation coil 3a respectively. 3b can maximize.

The excitation coils 3a and 3b are energized alternately. Will the exciter coil 3a energized, so acts on the ferromagnetic region 41a of the active element 4 a reluctance force covering this area 41a in the gap 5a at the stator 2a draws. The wave 105 , and thus the actuator membrane 104 , then moves down to the in 1 shown state. Will, however, the exciter coil 3b energized, the reluctance force acts on the ferromagnetic region 41b of the active element 4 and pull that area 41b in the gap 5b at the stator 2 B , The wave 105 , and thus the actuator membrane 104 , then moves starting from the in 1 shown state upwards.

2 shows a further embodiment of an active bearing 100 with a reluctance factor 1 according to the invention. The operating principle is the same as in 1 , However, the hydraulic components as well as the bearings have been omitted for the sake of clarity. The attacking bearing force F _L acts on the stamp from the outside 107 ; the counterforce F _G becomes with the reluctance factor 1 upset and over the shaft 105 to which the active element 4 of the reluctance actuator 3 is attached to the stamp 107 transfer. The wave 105 is through an air gap 105a from the stators 2a and 2 B spaced. In this air gap 105a this moves to the shaft 105 coupled active element 4 of the reluctance actuator 1 ,

In contrast to 1 is the first stator 2a from a first piece 21a made of SMC material and a ferromagnetic laminated core 25a as the second piece 22a acts, composed. The first piece 21a and the laminated core 25a limit a first gap 5a into which a first ferromagnetic area 41a of the active element 4 forming two air gaps 6a and 6b is insertable.

Analog is the second stator 2 B from a first piece 21b made of SMC material and a ferromagnetic laminated core 25b as the second piece 22b acts, composed. The first piece 21b and the laminated core 25b limit a second gap 5b into which a first ferromagnetic area 41b of the active element 4 forming two air gaps 6c and 6d is insertable.

The construction according to 2 is shorter overall and more compact. In particular, the ferromagnetic regions 41a and 41b of the active element 4 smaller dimensioned than according to 1 , This is the better focusing of the excitation coils 3a and 3b generated magnetic flux Φ on the circumferential column 5a and 5b through the laminated cores 25a and 25b owed.

3 is a partially cutaway perspective view of the in 2 shown active bearing 100 , It is only the area above the mounting plate 109 shown. The part with the most complex shape is the first piece 21a that together with the laminated core 25a the first stator 2a forms. By contrast, the first exciter coil 3a a prefabricated annular coil, and the laminated core 25a is a prefabricated ring binder. Both the exciter coil 3a as well as the bleached ring 25a Just in the first piece 21a be inserted. The comparatively complex form of the first piece 21a can be made of SMC material particularly easy by pressing.

4 illustrates how a stator 2 from four identical adjacent laminated cores 23a - 23d can be constructed. The levels passing through the ferromagnetic sheets of laminated cores 23a - 23d are all defined perpendicular to the drawing plane. These levels continue to run in the laminated cores 23a and 23c horizontally from left to right, as well as in the laminated cores 23b and 23d vertically from top to bottom. At the interfaces 24a - 24d in each case two of the laminated cores collide 23a - 23d together. This closes the respective interface 24a - 24d with the sheets in the adjacent laminated cores 23a - 23d each at an angle of 45 degrees. In this way, that of the rotating exciter coil 3 generated magnetic chained flux Ψ in the laminated cores 23a - 23d the wave 105 passing through an air gap 105a from the stator 2 is spaced, completely orbital.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011081291 A1 [0002]
• DE 102011011328 A1 [0003]
• DE 19634342 A1 [0005]
• DE 102014204165 A1 [0005]
• DE 102014204286 A1 [0005]

Claims (13)

Reluctance actuator ( 1 ) comprising at least one ferromagnetic stator ( 2 . 2a . 2 B ), at least one exciting coil ( 3 . 3a . 3b ) for introducing a magnetic chained flux Ψ into the stator ( 2 . 2a . 2 B ) as well as at least one active element ( 4 ), which is movable against the stator ( 2 . 2a . 2 B ), wherein the inductance L of the with the stator ( 2 . 2a . 2 B ) interacting exciter coil ( 3 . 3a . 3b ) at least from the position p of the active element ( 4 ), characterized in that the stator ( 2 . 2a . 2 B ) at least one gap ( 5 . 5a . 5b ) into which a ferromagnetic region ( 41 . 41a . 41b ) of the active element ( 4 ) is insertable. Reluctance actuator ( 1 ) according to claim 1, characterized in that the gap ( 5 . 5a . 5b ) to the ferromagnetic region ( 41 . 41a . 41b ) of the active element ( 4 ) corresponds. Reluctance actuator ( 1 ) according to one of claims 1 to 2, characterized in that the active element ( 4 ) next to the ferromagnetic region ( 41 . 41a . 41b ) a non-ferromagnetic carrier ( 42 ). Reluctance actuator ( 1 ) according to claim 3, characterized in that the carrier ( 42 ) at least ten times the volume of the ferromagnetic region ( 41 . 41a . 41b ) having. Reluctance actuator ( 1 ) according to one of claims 1 to 4, characterized in that the stator ( 2 . 2a . 2 B ) at least from a first piece ( 21 . 21a . 21b ) and a second piece ( 22 . 22a . 22b ) and the exciter coil ( 3 . 3a . 3b ) on one of the two pieces ( 21 . 21a . 21b ; 22 . 22a . 22b ) is wound. Reluctance actuator ( 1 ) according to one of claims 1 to 5, characterized in that the stator ( 2 . 2a . 2 B ) is at least partially made of a soft magnetic composite material, SMC. Reluctance actuator ( 1 ) according to one of claims 1 to 6, characterized in that the stator ( 2 . 2a . 2 B ) at least two adjacent laminated cores ( 23a - 23d ) consists of parallel, ferromagnetic, mutually insulated sheets. Reluctance actuator ( 1 ) according to claim 7, characterized in that the interface ( 24a - 24d ) between two adjacent laminated cores ( 23a - 23d ) with the plane of at least one sheet from each of the two laminated cores ( 23a - 23d ) includes an angle between 30 and 60 degrees, preferably between 40 and 50 degrees. Reluctance actuator ( 1 ) according to one of claims 1 to 8, characterized in that that of the exciter coil ( 3 . 3a . 3b ) generated magnetic chained flux Ψ by a laminated core ( 25a . 25b ) in the direction of the gap ( 5 . 5a . 5b ) is guided. Reluctance actuator ( 1 ) according to one of claims 1 to 9, characterized in that at least two stators ( 2a . 2 B ) with associated exciter coils ( 3a . 3b ) and columns ( 5a . 5b ) are provided and that the active element ( 4 ) at least two ferromagnetic regions ( 41a . 41b ), which are arranged to one another such that an increase of the inductance L of the one with the one stator ( 2a ) interacting exciter coil ( 3a ) the inductance L of the other with the other stator ( 2 B ) interacting exciter coil ( 3b ) decreased. Active warehouse ( 100 ), which compensates an attacking bearing force F _L at least partially by exerting a counterforce F _G , characterized in that at least one reluctance actuator ( 1 ) is provided according to one of claims 1 to 10 for exerting the counterforce F _G. Active warehouse ( 100 ) according to claim 11, characterized in that the active bearing ( 100 ) as a hydraulic bearing with a hydraulic chamber ( 101 ) for receiving hydraulic fluid ( 102 ) is formed, wherein the hydraulic chamber ( 101 ) between a receiving membrane ( 103 ) for receiving the attacking bearing force F _L and one to the reluctance actuator ( 1 ) coupled actuator membrane ( 104 ) for exerting the counterforce F _G. Active warehouse ( 100 ) according to one of claims 9 to 11, characterized in that it is designed as an engine mount for a motor vehicle.

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