CN107131210B

CN107131210B - Electromagnetic bearing with adjustable stiffness

Info

Publication number: CN107131210B
Application number: CN201710108520.8A
Authority: CN
Inventors: A·帕维莱茨; S·迈尔-扎尔费尔德; T·杨科夫斯基
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2016-02-26
Filing date: 2017-02-27
Publication date: 2020-09-15
Anticipated expiration: 2037-02-27
Also published as: DE102016203064A1; CN107131210A

Abstract

The invention relates to a bearing force F for receiving an action_LComprising a bearing force F to which a bearing device (100) is loaded_LAnd by a bearing force F_LA shaft (105) which is axially displaceable along an axis (100a), wherein the shaft (105) is additionally rotatably mounted and wherein a permanent magnet (6a, 6B) which interacts with a stationary electromagnet (10, 20) is coupled to the shaft (105) in such a way that a rotational angle α of the shaft (105) relative to the stationary electromagnet (10, 20) can be influenced by a magnetic field B generated by the stationary electromagnet (10, 20)₁Intensity and/or polarity modulation.

Description

Electromagnetic bearing with adjustable stiffness

Technical Field

The invention relates to a device for receiving a supporting force F_LIn particular for use as an engine mounting device in a vehicle.

Background

The internal combustion engine generates strong vibration excitations, which are transmitted to other vehicle components, by dynamic changes in the cylinder pressure thereof and by strongly oscillating inertial and moment variations on the crankshaft. In addition, the vehicle body is excited to produce torsion and vibration, which are regarded as disturbing vibrations and/or noise.

As a countermeasure, different types of passive and active bearing devices are used in the engine support device between the internal combustion engine and the vehicle body. The passive bearing arrangement dissipates the bearing force F acting through it in one or more damping elements_LThe energy introduced. The active bearing being acted upon by a counter-force F_GCompensating bearing forces F_L. Such a bearing device (in which a counter force F is electromagnetically applied)_G) For example, it is known from US 5,820,113A, US 2016/006333A 1, WO 2015/107012A 1 and WO 2015/197390A 1.

Hybrid passive and active support devices are also used. Such a hybrid bearing is embodied, for example, as a hydraulic bearing in which the hydraulic fluid moves through a throttle channel with a damping effect. The hydraulic fluid can be compressed or relieved by an additional actuator in order to suppress further vibration components.

Disclosure of Invention

According to the invention, a supporting force F for receiving the action is developed_LThe supporting device of (1). The supporting means comprising being loaded with a supporting force F_LAnd by a bearing force F_LA shaft axially movable along an axis.

The permanent magnet cooperating with the stationary electromagnet is coupled to the shaft in such a way that the angle of rotation α of the shaft relative to the stationary electromagnet can be influenced by the magnetic field B generated by the stationary electromagnet₁Intensity and/or polarity modulation.

The combination of the permanent magnet and the electromagnet forms a passive damping element which is designed to absorb the acting bearing force F_LProviding impedance and thus dissipating the energy of the undesired vibrations. Such a damping element requires less energy than an active bearing device, in which case a continuously alternating counter force F must be applied_G. In other words, passive damping elements are less flexible. In particular, there are few degrees of freedom with which the natural frequency can be changed in conventional passive components. It is important for effective damping of periodic vibrations that the damping element absorbs well at the frequency f, which is very representative in the spectrum of the undesired vibrations. This applies in particular to engine support devices in which the frequency spectrum of the vibrations depends on the engine load and the driving speed.

It has now been realized that the stiffness of the support device can be varied over a wide range by rotation of the shaft and the permanent magnets coupled to the shaft, which rotation can be adjusted by energizing the stationary electromagnets. The stiffness has the effect of the spring constant and is therefore an important factor which relates to the natural frequency and the amplitude of the support device. Therefore, the natural frequency can be adjusted in a wide range.

The reason for this is that the permanent magnet and the electromagnet respectively do not completely, but partially, surround the air gap region of the actuator around its axis. The permanent magnet can thus be completely or partially removed from the region of influence of the electromagnet by rotation of the shaft relative to the electromagnet. However, if the electromagnet no longer interacts with the entire volume of the permanent magnet, the shaft is coupled to the electromagnet overall less strongly and the rigidity of the bearing is reduced.

In particular, the electromagnet can be switched into an attractive or repulsive interaction with the permanent magnet by changing the current direction in which the current flows through the electromagnet. The stiffness is greater in the case of attractive interaction and less in the case of repulsive interaction.

In a particularly advantageous embodiment of the invention, the permanent magnet and the stationary electromagnet are arranged opposite one another along the outer circumference of the shaft and/or along the outer circumference of the reaction element concentric to the shaft. Their effects may be superimposed along the magnetic axis.

In a further particularly advantageous embodiment of the invention, the shape of the permanent magnet on the one hand and the shape of the pole shoe of the electromagnet which is stationary on the other hand correspond to one another. The permanent magnets and the pole shoes may have, for example, mutually adapted bends, so that the electromagnet can pass parallel to the surface of the pole shoe from this surface when the shaft rotates. The width of the air gap between the permanent magnets and the pole shoes constitutes another degree of freedom which has an influence on the stiffness of the support device.

In a further particularly advantageous embodiment of the invention, provision is additionally made for the bearing force F to be adjusted in relation to the force of rotation_LCounter force F directed in the axial direction in the opposite direction_GAn electromagnetic reluctance actuator applied to the shaft. In this combination, the passive damping element, which is formed on the one hand by a stationary electromagnet and a permanent magnet, and on the other hand the reluctance actuator complement each other in a coordinated manner. Passive damping elements require current for the electromagnet, as do reluctance actuators. If an electromagnetic passive damping element is also added to the magnetoresistive actuator, it appears at first glance that the energy consumption is increased overall. But surprisingly the opposite is true: the combination requires less energy than just one reluctance actuator in order to suppress vibrations of the same frequency spectrum.

The reason for this is that balancing the periodic oscillations by means of a reluctance actuator requires just an excess of energy,since the electromagnet of the reluctance actuator must always switch magnetic properties repeatedly. When the natural frequency of the damping element is suitable, which can be adjusted according to the invention according to the electrical path, vibrations can be suppressed more efficiently by the passive damping element. Conversely, the acting bearing force F_LCan be suppressed more effectively by the magneto resistive actuator than by the passive damping element. By transferring this task to the reluctance actuator, the permanent magnet in the damping element can be designed with smaller dimensions. Accordingly, the amount of the required very expensive rare earth magnetic material is reduced.

Overall, the combination of passive damping element and magnetoresistive actuator has a flexibly configurable force-frequency characteristic over a wide frequency range with a simultaneously significantly reduced energy requirement. The energy saving in turn results in significantly fewer demands being placed on the control electronics with regard to the maximum current required. Current active engine mounts (which operate solely via a reluctance actuator without a damping element) require more current in any case than can be provided by the engine controller. Many other control tasks have been incorporated into engine controllers, and a separate controller is only required for the operation of the active engine mounts. The current demand is now reduced by the combination with the damping element into a range in which the engine controller can meet the energy demand. At the same time, the electronic components for actuation can also be dimensioned for smaller currents, so that smaller and more cost-effective components can be used. This is also beneficial for the purpose of integrating the handling of the engine support device into the engine controller.

Advantageously, the following regions are offset from one another along the axis of the support device: in these regions, the axial movement of the shaft is damped on the one hand by the permanent magnets interacting with the stationary electromagnets and on the other hand by the application of a counter force F by means of the reluctance actuator_GIs compensated for. The shaft then only has to be provided with the ferromagnetic active elements of the permanent magnets and/or the reluctance actuators in a limited section, not along its entire length. In generalThe mass moving with the shaft is thereby reduced, so that the inductance L of the electromagnet can be kept small, which in turn enables a higher operating frequency.

This is particularly relevant in another particularly advantageous embodiment of the invention, in which the magnetoresistive actuator has at least one further stationary electromagnet, the inductance L of which depends on the axial position p of the shaft along the axis of the bearing, and at least one ferromagnetically acting element concentric to the shaft. The further electromagnet can also be designed with a smaller inductance L and thus for higher operating frequencies.

In a further particularly advantageous embodiment of the invention, the ferromagnetically acting element and the further stationary electromagnet are arranged relative to one another such that the inductance L of the further stationary electromagnet, with a constant axial position p of the shaft along the axis, depends on the angle of rotation α of the shaft, the rotation of the shaft by the stationary magnet of the damping element has an effect not only on the stiffness of the damping element, but also on the stiffness of the magnetoresistive actuator, the functional dependency of the stiffness of the magnetoresistive actuator on the angle of rotation α then being a supporting force F for adapting the entire bearing to act_LAnother degree of freedom of the spectrum of (a).

In order to make the stiffness of the magnetoresistive actuator dependent on the angle of rotation α, the magnetically active element advantageously has at least one evagination which extends along a portion of the outer circumference of the magnetically active element. The shape of the at least one eversion corresponds to the shape of the pole shoe of the further stationary electromagnet. In a similar manner to the interaction of the permanent magnet and the associated stationary electromagnet, the evagination can be rotated into or out of the active region of the further stationary electromagnet. The more the evaginations are located in the region of action, the stronger and stiffer the magnetoresistive actuator acts on the shaft.

In a further particularly advantageous embodiment of the invention, the magnetization B of the further stationary electromagnet₂With a direction fixed relative to a position co-operating with the permanent magnetMagnetization of (B)₁Is at right angles to the direction of (a). For example, a concentrically arranged laminated stator can be used to guide the two fluxes. The volume of the stator is optimally utilized by the magnetic fluxes at right angles to each other.

In a further particularly advantageous embodiment of the invention, at least one electromagnet which interacts with the permanent magnet in the region of the further stationary electromagnet is arranged along the axis of the bearing. The electromagnetically variable damping element on the one hand and the reluctance actuator on the other hand do not occupy a non-intersecting space in the bearing arrangement, but rather appear to nest with one another. This in turn provides another degree of freedom in terms of adjustability and also improves the use of space in the support device. The improved space utilization in turn results in that the shaft can be produced shorter and its moving mass is thereby reduced. This can further increase the natural frequency of the bearing device.

The space obtained by the mutual nesting of the damping element and the reluctance actuator can also be used for lengthening the permanent magnet in the direction of the shaft. Rare earth magnets have a particularly large flux density per unit volume, but are also, for this reason, approximately 50 times more expensive than ferrite-based permanent magnets, for example. The ferrite magnet is far less than the rare earth magnet by 50 times, so that the ferrite magnet obviously has better cost performance. By constructing a space for placing the voluminous ferrite magnets, the overall cost of the support device is significantly reduced.

In accordance with the preceding description, the bearing device is advantageously designed as an engine bearing device for a vehicle, since the bearing forces F acting there are_LThe frequency f received by the supporting means is continuously shifted. The versatile adjustability of the support device plays a particular role here.

In a further particularly advantageous embodiment of the invention, the current intensity I and/or the frequency f of the current flowing through the stationary electromagnet interacting with the permanent magnet is/are pre-controlled as a function of the number of engine revolutions of the vehicle. In this way, for example, the damping element can be operated at a natural frequency which covers the bearing force F involved_LMost of the vibrations in (2). The division of the division between the damping element and the magnetoresistive actuator is thus madeOptimizing: bearing force F_LThe periodic component of the energy consumption which leads to the greatest possible energy consumption when adjusted solely by the magnetoresistive actuator is absorbed exactly energetically more advantageously by the damping element.

Drawings

Further measures which improve the invention are shown in detail below together with the description of preferred embodiments of the invention with reference to the drawing.

The figures show:

fig. 1 is a top view of a support device 100 according to the invention along its axis 100 a;

fig. 2 shows a sectional view of the support device in the yz plane in fig. 1.

Detailed Description

According to fig. 1, the support device 100 comprises an attenuation element with adjustable stiffness, which is constituted by electromagnets 10 and 20 combined with

permanent magnets

6a and 6 b. The permanent magnet is mounted on a ferromagnetic reaction element 4 which is fitted concentrically with the shaft 105 and with which it can both move in the axial direction along the axis 100a of the support device 100 and rotate about this axis 100 a. The axis 100a of the bearing arrangement 100 corresponds to the z-axis in the coordinate system of fig. 1 (in which the axes x and y lie in the drawing plane), which axis emerges perpendicularly from the drawing plane.

The electromagnets 10 and 20 include a

pole piece

11 or 21 and a coil 12 or 22, respectively. The coils 12 or 22 of the electromagnets 10 and 20 are preferably connected in series. Magnetization B of electromagnets 10 and 20 when coil 12 or 22 is energized in the forward direction₁Are illustrated by means of an arrow respectively.

The support device 100 further comprises a reluctance actuator 2. The magnetoresistive actuator 2 is formed from two further, positionally fixed

electromagnets

30 and 40 and a ferromagnetic reaction element 4. The

further electromagnets

30, 40 comprise a

pole piece

31 or 41 and an

electromagnetic coil

32 or 42, respectively. Magnetization B of

additional electromagnets

30 and 40 when

coil

32 or 42 is energized in the forward direction₂Are illustrated by means of an arrow respectively. Magnetization B of

electromagnets

30 and 40₂In the direction of the magnetization B of the electromagnets 10 and 20₁Is at right angles to the direction of (a).

The

further electromagnets

30 and 40 interact with the reaction element 4 via the

eversions

4a and 4b on the reaction element 4. The further electromagnet is offset downwards along the axis 100a of the support device 100, i.e. only starts below the plane of the drawing, with respect to the electromagnets 10 and 20 responsible for damping. Likewise, the

eversions

4a and 4b on the reaction element 4 are also situated completely below the plane of the drawing.

The

permanent magnets

6a and 6b and the

extensions

4a and 4b on the active element 4 have a shape corresponding to the shape of the pole shoes 11, 21, 31 and 41. Therefore, the shaft 105 itself can rotate freely without the

permanent magnets

6a and 6b or the inside-

out portions

4a and 4b colliding on one of the

pole pieces

11, 21, 31, and 41.

The assembly constituted by the shaft 105, the active element 4 and the two

permanent magnets

6a and 6b, which constitutes the entire moving mass (prime mover), has two magnetic axes P and Q. The first magnetic axis P is determined by the perpendicular bisector of the two

permanent magnets

6a and 6 b. A second magnetic axis Q, at right angles to the first, is determined by the perpendicular bisector of the two

eversions

4a and 4b of the reaction element 4.

In the de-energized and non-loaded state, the first magnetic axis P of the prime mover is parallel to the x-axis and the second magnetic axis Q of the prime mover is parallel to the y-axis. The same applies when both electromagnetic coils 12 and 22 of the electromagnets 10 and 20 are energized in the forward direction. The positive energization of the two electromagnetic coils 12 and 22 increases the rigidity of the support device 100 with respect to the oscillation damping. Upon negative energization of the solenoid coils 12 and 22, the prime mover twists tangentially by an angle α, as shown in FIG. 1. The magnetic Q axis of the motive body is parallel to the coordinate axis designated by y'. The magnetic axes of the motive body on the one hand and the

electromagnets

10, 20, 30 and 40 which are stationary on the other hand are no longer coincident. The stiffness of the support device 100 to oscillations in the direction of the axis 100a of the support device decreases due to two effects: the

permanent magnets

6a and 6b are partly turned out of the region of action of the

pole shoe

11 or 21 on the one hand, and the

evaginations

4a and 4b of the active element 4 are partly turned out of the region of action of the

pole shoe

31 or 41 on the other hand.

All pole shoes 11, 21, 31 and 41 are preferably laminated by the stamping lamination method (stanzpaketierbetsmethode). These pole shoes are inserted into recesses on the inner circumference of the common, circumferential laminated stator 1.

Fig. 2 is a sectional view in the yz plane of the support device shown in fig. 1, which illustrates the series connection of the damping element and the magnetoresistive actuator 2 on a common axis 105 and the assembly of the entire system. The entire support device 100 is inserted into a housing 106 delimited by two flanges 108c and 108 d. A first sliding bearing 108a for the shaft 105 is arranged in the flange 108 c. A second sliding bearing 108b for the shaft 105 is arranged in the flange 108 d. The two sliding bearings 108a, 108b allow both the axial movement of the shaft 105 along the axis 100a of the support device 100 and the rotation of the shaft 105 itself, respectively.

In the perspective view of fig. 2, the electromagnet 10 of the damping element, which electromagnet interacts with the permanent magnet, and the permanent magnet 6a are located in front of the plane of the drawing and are therefore not drawn. The electromagnet 20 and the permanent magnet 6b, which cooperate with the latter, are located behind the plane of the drawing in the perspective view. They are indicated by dashed or dotted lines.

The reluctance actuator 2 is located in the perspective view of fig. 2, visible in the front part. Since the

electromagnets

30 and 40 belonging to the reluctance actuator are in one plane, the reluctance actuator 2 can only cause an axial movement of the shaft 105 in one direction (here to the left). For the movement in the other direction, a pressure spring 111 is provided, which is supported on one side on the magnetically active element 4 and on the other side on a cover plate 108e in the housing 106.

The damping element and the magnetoresistive actuator 2 can in principle be actuated independently of one another. For example, the magnet coils 12 and 22 belonging to the damping element can be actuated with a constant current, the intensity of which depends on the bearing force F involved in the action_LThe intensity and frequency f of the vibration in (1). However, the electromagnetic coils 12 and 22 can also be operated, for example, with an alternating current. The magnetic coils 32 and 42 of the magnetoresistive actuator can be actuated, for example, in the form of a pulse train, the frequency of which is adapted to the vibration component remaining after passing through the damping element in the movement of the shaft 105.

Claims

1. For receiving effectsBearing force F_LComprising a bearing force F to which a bearing device (100) is loaded_LAnd by a bearing force F_LA shaft (105) axially movable along the axis (100a),

it is characterized in that the preparation method is characterized in that,

the shaft (105) is additionally rotatably mounted and permanent magnets (6a, 6B) cooperating with the stationary electromagnets (10, 20) are coupled to the shaft (105) in such a way that a rotation angle α of the shaft (105) relative to the stationary electromagnets (10, 20) can be influenced by a magnetic field B generated by the stationary electromagnets (10, 20)₁Wherein additionally provision is made for the relative bearing force F to be adjusted with respect to the strength and/or polarity_LCounter force F directed in the axial direction in the opposite direction_GAn electromagnetic reluctance actuator (2) applied to the shaft (105), wherein the reluctance actuator (2) has at least one further stationary electromagnet (30, 40) and at least one ferromagnetically acting element (4) concentric to the shaft (105), wherein the inductance L of the further stationary electromagnet (30, 40) is dependent on the axial position p of the shaft (105) along the axis (100a) of the bearing arrangement (100).

2. The supporting installation (100) according to claim 1, characterised in that the permanent magnets (6a, 6b) and the stationary electromagnets (10, 20) are arranged opposite each other along the outer circumference of the shaft (105) and/or along the outer circumference of an active element (4) concentric to the shaft (105), respectively.

3. The supporting device (100) according to claim 1 or 2, characterized in that the shaping of the permanent magnets (6a, 6b) on the one hand and the shaping of the pole shoes (11, 21) of the stationary electromagnets (10, 20) on the other hand correspond to each other.

4. The support device (100) according to claim 1 or 2, characterized in that the following areas are offset from each other along the axis (100a) of the support device (100): in these regions, the axial movement of the shaft (105) is fixed to the positionThe permanent magnets (6a, 6b) which interact with the fixed electromagnets (10, 20) are damped and, on the other hand, the opposing force F is applied by means of the magnetoresistive actuator (2)_GIs compensated for.

5. The bearing arrangement (100) according to claim 1 or 2, wherein the ferromagnetically acting element (4) and the further stationary electromagnet (30, 40) are arranged relative to each other such that the inductance L of the further stationary electromagnet (30, 40) is dependent on the angle of rotation α of the shaft (105) with a constant axial position p of the shaft (105) along the axis (100a) of the bearing arrangement (100).

6. Support device (100) according to claim 5, characterized in that the ferromagnetically acting element (4) has at least one eversion (4a, 4b) extending along a portion of the outer circumference of the ferromagnetically acting element (4).

7. A support device (100) according to claim 6, wherein the shape of at least one of the evaginations (4a, 4b) corresponds to the shape of the pole shoes (31, 41) of the further stationary electromagnets (30, 40).

8. Support device (100) according to claim 1 or 2, characterized in that the magnetization B of the further stationary electromagnets (30, 40)₂With respect to the magnetization B of the stationary electromagnet (10, 20) co-operating with the permanent magnet (6a, 6B)₁Is at right angles to the direction of (a).

9. The support device (100) according to claim 1 or 2, characterized in that at least one electromagnet (10, 20) cooperating with a permanent magnet (6a, 6b) is arranged along the axis (100a) of the support device (100) in the region of the further stationary electromagnet (30, 40).

10. The bearing arrangement (100) according to claim 1 or 2, characterized in that it is advantageously configured as an engine bearing arrangement for a vehicle.

11. The supporting installation (100) according to claim 10, characterised in that the current intensity I and/or the frequency f of the current flowing through the stationary electromagnets (10, 20) co-acting with the permanent magnets (6a, 6b) is pre-controlled as a function of the number of engine revolutions of the vehicle.