DE102017202082A1 - Device for stepless damping of rotational relative movements - Google Patents

Abstract

A device is provided for stepless damping of rotary relative movements, comprising at least one electromagnet (10) comprising a magnet yoke (11) with at least one magnet coil (12) and a magnet armature (20) connected torsion-proof with a first shaft (2) and displaceable in the axial direction ) with a frontal Wirbelstromtopf (21). The eddy current pot (21) and the electromagnet (10) are arranged relative to one another such that a magnetic field generated by the magnet coil (12) can exert a magnetic force on the magnet armature (20). The device also has a second shaft (22). non-rotatably connected disc (30) which is provided with a plurality of spaced apart on its outer circumference and each with a pole facing outwards permanent magnet (31), wherein the disc is shaped and arranged so that they at least in the Wirbelstromtopf (21) is partially receivable.

Description

The present invention relates to a device for stepless damping rotatory relative movements according to the preamble of patent claim 1 and a corresponding method.

It is known that with eddy current brakes and eddy current couplings a variable momentum can be set directly via a defined current flow. If the coil is energized, i. When a current flows through the coil, a magnetic field is created whose lines of force close over the poles of the coil, a working air gap and the armature ring. In clutches eddy currents are generated by running the two coupling halves with different speeds in the anchor ring. These are exploited to create a dragging or braking moment.

So far, however, there is no continuous geometric variation. Couplings also have the difficulty of transmitting the electrical energy to rotating parts. Usually, this is accomplished with expensive, high-maintenance and due to the friction lossy sliding contacts.

Therefore, it is an object of this invention to provide a device which overcomes these disadvantages. This object is achieved by the features of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The essence of the invention is to provide a continuously variable damper based on the eddy-current principle for rotational relative movements, wherein the adjustment takes place by means of electromagnetic direct drive. The device is advantageously used in eddy current couplings or eddy current brakes.

Provided is a device for stepless damping rotatory relative movements, comprising at least one electromagnet, comprising a magnetic yoke with at least one magnetic coil and a rotationally connected to a first shaft connected and movable in the axial direction armature with a front eddy current pot. The Wirbelstromtopf and the electromagnet are arranged to each other such that a magnetic field generated by the magnetic coil can exert a magnetic force on the armature.

Further, the device comprises a non-rotatably connected to a second shaft disc, which is provided with a plurality on its outer periphery side by side and each with a pole facing outward permanent magnet, wherein the disc is shaped and arranged so that it at least in the Wirbelstromtopf is partially receivable.

By the device can be a continuously adjustable damping effect for a rotational relative motion, which is not only energy efficient, since the damping is generated by permanent magnets, but also non-contact and thus abrasion, noise and wear.

The use of permanent magnets on the disc and the electromagnet no error-prone electrical contacting of rotating components is required. Due to the electromagnetic direct drive, fewer components are required than with previous solutions. In addition, a highly dynamic adjustment of the position of the magnet armature via the magnetic field generated by the electromagnet is possible.

Another advantage is that the electromagnetic direct drive has good inherent diagnostic properties, e.g. a reconstruction of the anchor position and actuator temperature can be done from the voltage and current curves.

In addition, the force required to adjust the damping effect is independent of the damping effect. It can therefore be realized with a small force and thus energy efficient a large attenuation.

In one embodiment, the device comprises a spring which is shaped and arranged on the armature, that the position of the armature in the axial direction is adjustable. Advantageously, the spring is selected in its spring action, that in its rest position it presses the Wirbelstromtopf in a position in which it at least partially receives the disc with the permanent magnet.

In order to move the armature back to its original position, the use of a spring as a return means is advantageous. Depending on the design can be selected by the choice of the spring for the rest position, a position in which no energizing the electromagnet is needed, which in turn can be saved energy.

In one embodiment, the permanent magnets are arranged alternately in pairs opposite to each other. By this arrangement, a nearly optimal distribution of the eddy currents is generated.

In one embodiment, the armature is movably disposed on the first shaft in the axial direction, or the armature is connected to the first shaft connected and the first shaft is movable in the axial direction. Depending on the design, the mobility in the axial direction of the armature can be made as required by this is movably arranged, for example via a bearing on the first shaft or formed integrally with the shaft and can be moved together with the shaft in the axial direction.

In one embodiment, the Wirbelstromtopf is formed of electrically conductive material, and areas that are opposite to the magnetic coil of the electromagnet, are formed of a magnetizable material.

By using a magnetizable metal only at the areas that are affected by the magnetic effect of the energized coil, both weight and cost can be saved. Magnetizable metals are, for example, (galvanized) steel, which is heavier and more expensive than non-magnetizable but electrically conductive aluminum.

In one embodiment, in addition, the side walls of the Wirbelstromtopfs are formed of a magnetizable material. Advantageously, the thickness of the permanent magnets is chosen such that they can be used for displacement of the armature in the axial direction. By choosing a magnetizable material for the sidewalls and additionally choosing the (magnetic) strength of the permanent magnets, a recovery of the armature can be accomplished solely by the permanent magnets, i. no additional return element like a spring is needed.

In one embodiment, areas of the side walls of the Wirbelstromtopfes are provided in the rest position with recesses in the region opposite to the permanent magnet. By recesses in appropriate shape and size in the side walls, the effect of the eddy currents is reduced or negligible. Thus, a rest position of the magnet armature can take place, in which the disc is accommodated in the eddy current pot, so it is covered, but no eddy currents are induced.

Furthermore, a method for stepless damping rotatory relative movements of a proposed device is provided, wherein for moving the Wirbelstromtopfes in the axial direction, the at least one magnetic coil of the electromagnet is energized, whereby the eddy current pot of the magnet armature is displaced in the axial direction due to the resulting magnetic field in such a way that Preset degree of overlap of the permanent magnets by the Wirbelstromtopf arises.

Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, with reference to the figures of the drawing, the inventive details shows, and from the claims. The individual features can be realized individually for themselves or for several in any combination in a variant of the invention.

Preferred embodiments of the invention are explained below with reference to the accompanying drawings.

1 shows a representation of the device according to the invention according to an embodiment of the present invention. Shown is an electromagnet 10 with a magnetic yoke 11 with at least one magnet coil arranged therein 12 ,

Above the electromagnet 10 , in 1 to the left, an axial, ie in the Y direction, is displaceable and with a first wave 22 non-rotatably connected magnet armature 20 with a frontal Wirbelstromtopf 21 arranged. Front side means that the opening of the pot for receiving the disc 30 on the electromagnet 10 facing away.

In this embodiment is above the armature 20 , so in turn 1 to the left, one with a second wave 33 non-rotatably connected disc 30 , which has a plurality of permanent magnets arranged side by side on its outer side and each with one pole pointing outwards 31 is provided.

The number of permanent magnets 31 can be chosen depending on the version. Advantageously, the pairs of opposite polarity are arranged to each other, so that each show an N-pole and an S-pole alternately outward. This causes the induced eddy currents between permanent magnets 31 and sidewalls of the eddy current pot 21 better or even optimally distributed.

The disc 30 is shaped and arranged to enter the eddy current pot 21 is at least partially receivable to achieve the damping effect of the invention when it is moved axially in their direction. That is, the diameter of the disc 30 advantageously smaller than the diameter of the Wirbelstromtopfs 21 , where here a difference is sufficient, so that eddy current pot 21 and disc 30 do not touch. Advantageous and common is that disc 30 and eddy current pot 21 are circular, but the invention is not limited to this shape.

Furthermore, the invention is not on the in 1 limited execution shown in which the eddy current pot 21 between disc 30 and electromagnet 10 is arranged. In this version is the second shaft 33 arranged on the eddy current pot 21 side facing away. It is also conceivable that the electromagnet 10 is arranged in a different position than in 1 shown as long as the function is fulfilled, that of the eddy current pot 21 over the glass 30 or the permanent magnets 31 the disc 30 through the magnetic field of the electromagnet 10 can be adjusted to the disc 30 to cover at a pre-set level without affecting other functions.

Depending on the degree of overlap of the permanent magnets 31 through the sidewalls of the Wirbelstromtopfs 21 a more or less damping or decelerating effect is achieved. Depending on the axial position (Y direction in 1 ) of the magnet armature 20 are the ones with the first wave 22 non-rotatably connected eddy current pot 21 and those with the second wave 33 non-rotatably connected disc 30 with the arranged on its periphery and with a pole thereof outward permanent magnet 31 covered to different degrees. A non-vanishing relative angular velocity between the disc 30 with the permanent magnets 31 and the eddy current pot 21 that is between the first and the second wave 22 respectively. 33 , now causes that in the Wirbelstromtopf 21 , more precisely whose sidewalls, eddy currents are induced. These lead to a relative angular velocity opposite torque. This torque is greater, the greater the relative angular velocity and the greater the overlap between Wirbelstromtopf 21 and disc 30 with the permanent magnets 31 is. The relative movement is attenuated speed-dependent, wherein the damping torque increases more and more with increasing relative rotational speed, the farther the eddy current pot 21 and the disc 30 with the permanent magnets 31 are covered. By adjusting the overlap, ie by axial displacement (in the Y direction in 1 ) of the eddy current pot 21 , therefore, the damper characteristic can be adjusted.

The axial displacement takes place with the electromagnet 10 , By energizing the solenoid 12 A magnetic force is applied to the axially displaceable magnet armature 20 with the eddy current pot 21 generated.

If the magnet armature 20 in rest position in overlap with the disc 30 or the permanent magnet 31 is and no recesses on the permanent magnet 31 opposite areas of the sidewalls of the Wirbelstromtopfs 21 has, the magnet armature 20 with the eddy current pot 21 then deflected against, for example, a return spring, not shown, in 1 to the right. That means that the previously in the magnet armature 20 or the Wirbelstromtopf 21 recorded disc 30 less of the magnet armature 20 is covered, so that a lower damping results. When the current in the solenoid coil 12 is reduced, the magnet armature 20 moved by the return spring to the left, so again a larger coverage of the disc 30 or the permanent magnet 31 takes place, whereby the damping or braking effect is increased again.

With appropriate design of the spring, if any, any intermediate position between the maximum and minimum air gap between solenoid 10 and magnet armature 20 or eddy current pot 21 be set stable without controller. Decisive here is that the spring force of the spring increases faster during compression than the magnetic force increases with decreasing air gap.

Alternatively, the electrical control unit of the actuator may have a position controller for continuously adjusting the axial position. This allows the use of a less stiff return spring and thus less electrical energy is needed for adjustment. In addition, a weaker and thus cheaper and smaller solenoid can be used.

For position control, the actuator can either have a dedicated position sensor for the axial position of the armature 20 own or it will be detected by the electrical control unit, the gradients of coil voltage and coil current and reconstructed the anchor position. For this purpose, various methods are known.

Alternatively, the electromagnet 10 and the spring be designed so that only a bistable operation is possible. The spring acting as a return spring then only has to be able to overcome the magnetic remanence force after switching off the coil current with a minimum air gap. It can then be used so a particularly weak return spring. Thus, then a particularly energy-efficient adjustment of the axial position of the actuator is possible.

In addition, in a further embodiment, the spring can be dispensed with, if the material of the magnet armature 20 , especially the Wirbelstromtopfes 21 , is suitably chosen. For the embodiment described above, it is sufficient for the areas of the Wirbelstromtopfs 21 , which of the magnetic coil 12 opposite to use a material that is magnetizable. The remaining area may be made only of an electrically conductive material, eg aluminum. If no spring is to be used, the entire eddy current pot can also be used 21 , especially the side walls thereof, be formed of a magnetizable material. In addition, the strength, ie the (magnetic) force, of the permanent magnets 31 chosen so that they replace the (return) spring. That means the permanent magnets 31 then serve the magnet armature 20 to keep in a resting position.

In another embodiment, at the region of the sidewalls of the Wirbelstromtopfs 21 , in the rest position the permanent magnets 31 opposite, recesses or openings provided. These recesses or openings should be as large as possible, so that the most negligible eddy currents occur. It may well be present in the recesses or openings several interruptions, for example in the form of retaining webs to maintain a stable arrangement. Through the recesses, a rest position can be realized by, for example, the described return spring, in which no damping takes place, but the Wirbelstromtopf 21 nevertheless over the disk 30 is arranged so that no (electrical) energy has to be expended to the eddy current pot 21 or the magnet armature 20 to keep in the resting position. For damping, the magnet armature 20 then adjusted by the applied magnetic field so that the side walls of the Wirbelstromtopfs not provided with recesses or openings 21 again the permanent magnets 31 cover to a desired degree.

The device can be used both in brakes and in clutch. When used in brakes should either the disc 30 with the permanent magnets 31 or the armature 20 against rotation with the housing instead of a shaft 22 or 33 be connected.

Also, a combination may be made with two-mass oscillators, e.g. an adjustable vibration absorber, for example, for transmission.

Also, the device can be used in a corresponding embodiment as emergency damping. In normal operation is the electromagnet 10 energized and the magnet armature 20 attracted to minimal air gap, the Wirbelstromtopf 21 and the disc 30 with the permanent magnets 31 are then so minimal or not covered, and thus only a very little or no torque transfer on the damper is possible. At a drop in the supply voltage of the electromagnet 10 the magnetic force is so low that the armature 20 is reset by the return spring, so that the overlap between eddy current pot 21 and disc 30 with permanent magnets 31 Thus, the maximum becomes, and thus the transmittable moment becomes maximum. Thus, for example, a smooth braking effect can be achieved in the event of power loss.

The magnet armature 20 can on the first wave 22 be arranged slidably, for example via a mechanical device such as a warehouse. He can also do it with the first wave 22 be formed integrally, so that he together with the first wave 22 is displaceable in the axial direction.

The material to be displaced by the magnetic force should be magnetizable, i. not magnetic per se, but only magnetic due to the action of a magnetic field, i. also their orientation is defined by it.

LIST OF REFERENCE NUMBERS

10

electromagnet

11

yoke

12

solenoid

20

armature

21

Eddy current pot

22

first wave

30

disc

31

permanent magnets

33

second wave

X-Y-Z

coordinate system

Claims (10)

Device for stepless damping rotational relative movements, with at least - An electromagnet (10) comprising a magnetic yoke (11) with at least one magnetic coil (12), - One with a first shaft (22) secured against rotation and displaceable in the axial direction armature (20) with a frontally arranged Wirbelstromtopf (21), wherein the Wirbelstromtopf (21) and the electromagnet (10) are arranged to each other such that a through the Magnetic coil (12) generated magnetic field can exert a magnetic force on the armature (20), and - One with a second shaft (33) against rotation connected disc (30) which is provided with a plurality of its outer side by side and each with a pole facing outward permanent magnet (31), wherein the disc (30) is shaped and arranged in that it is at least partially receivable in the eddy current pot (21). Device after Claim 1 , with a spring shaped and fixed to the magnet armature (20) is arranged, the position of the armature (20) in the axial direction is adjustable. Device after Claim 2 wherein the spring is selected in its spring action so that in its rest position, it presses the Wirbelstromtopf (21) in a position in which it at least partially receives the disc (30) with the permanent magnet (31). Device according to one of the preceding claims, wherein the permanent magnets (31) are arranged in pairs alternately opposite to each other. Device according to one of the preceding claims, wherein the magnet armature (20) on the first shaft (22) is arranged to be movable in the axial direction, or the magnet armature (20) is connected to the first shaft (22) and the first shaft (22) in axial direction is movable. Device according to one of the preceding claims, wherein the Wirbelstromtopf (21) is formed of electrically conductive material, and areas which are opposite to the magnetic coil (12) of the electromagnet (10) are formed of a magnetizable material. Device after Claim 6 wherein sidewalls of the eddy current pot (21) are formed of a magnetizable material. Device after Claim 7 , wherein the thickness of the permanent magnets (31) is selected such that they are used for the displacement of the armature (20) in the axial direction. Device according to one of the preceding claims, wherein side walls of the Wirbelstromtopfes (21) are provided with recesses which are in a rest position in the region opposite to the permanent magnets (31). Method for stepless damping of rotational relative movements of a device according to one of the preceding claims, wherein for moving the Wirbelstromtopfes (21) in the axial direction, the at least one magnetic coil (12) of the electromagnet (10) is energized, whereby the Wirbelstromtopf (21) of the magnet armature (20 ) is displaced in the axial direction due to the resulting magnetic field such that a preset degree of overlap of the permanent magnets (31) by the Wirbelstromtopf (21) is formed.

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