DE102022116169A1 - DRIVE AND METHOD FOR OPERATING A DRIVE - Google Patents

Abstract

Swash plate drive, comprising a swash plate and a stator, the drive being designed such that a magnetic field generated by permanent magnets and modulated by electromagnetic windings acts on the swash plate in such a way that the swash plate transmits a torque via a constant velocity joint to an output shaft.

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to a swashplate drive and a method for operating a swashplate drive.

TECHNICAL BACKGROUND

From publications like US 3,492,515 , DE 100 28 964 A1 , DE 1 763 078 A1 , US 10,574,109 B2 Drives are known which use magnetic forces to cause a round, ferromagnetic disk to wobble.

The movable swash plate is mechanically toothed at its point of contact with the fixed drive part - also called the stator - with the stator-side toothing having at least one tooth less than the disk-side toothing.

The wobbling movement creates a relative movement between the swash plate and the stator, which can be transmitted to an output shaft.

The advantage here is that very high gear ratios - wobbling movement to the output shaft - can be achieved.

The disadvantage is the rather unfavorable magnetic utilization of the drive, since magnetic forces can only generate torque in the vicinity of the contact area between the disk and the stator.

In addition, due to its principle, the drive is a reluctance motor with the corresponding properties such as a poor power factor and the resulting high current consumption.

SUMMARY OF THE INVENTION

This invention is therefore based on the object of optimizing the drive mentioned in relation to torque to volume or torque to weight - hereinafter also referred to as torque density.

This task is solved by the features specified in claims 1, 7 and 9. Advantageous refinements are described in the respective dependent patent claims.

In one aspect of the invention, a round swashplate may have two areas of minimum air gap. Areas with the smallest air gap are areas where the swash plate and the stator come very close to each other or are only very close apart or can even touch each other at certain points.

The first area can be located on a first flat side of the swash plate, the second area can be located on a second flat side of the disc that is diagonally opposite the first flat side.

The stator therefore forms a gap in which the swashplate is located. The axial thickness of the swashplate is not enough to bridge the gap, so the swashplate must tilt to contact the stator on both sides of the gap.

A permanent magnetic field can now be generated in the stator, which enters the swashplate in the first area, spreads through the swashplate and exits the swashplate again in the second area.

Magnetic field lines are always self-contained. Therefore, the inference (i.e. the closing of the magnetic field or the return or the closing of the magnetic circuit) of the magnetic field takes place outside (in particular not via the swash plate) of the swash plate via a magnetically soft material, hereinafter also referred to as a magnetic yoke. This magnetically soft material connects the two stator parts together.

In the areas of the smallest air gaps, high magnetic attractive forces can now prevail between the stator and the swashplate, which can hold the swashplate in its tilted position in a defined manner.

This type of basic magnetic excitation through a permanent magnetic field is new in swashplate drives and enables higher torque densities, better performance factors and continuous gear meshing even when the drive is de-energized.

In an advantageous embodiment, the magnetic field can be generated by permanent magnets.

One or more permanent magnets can be arranged in the magnetic circuit on the stator side.

Alternatively, the permanent magnetic field could also be implemented via an electrical winding through which direct current flows.

In a further advantageous embodiment, electromagnetic coils can be arranged between the swashplate and the stator on both sides of the swashplate. The field generated by the permanent magnets could be spatially and temporally modulated by the coils in order to force the swashplate into a rolling movement.

The magnetic field can only be shifted in space and time by the coils, but it cannot be generated. This means the coils can be relatively small.

Making the coils smaller can result in a reduction in volume and weight, which in turn increases torque density.

The drive can also work with coils attached to one side only, but then at the expense of torque density.

In a further advantageous embodiment, a magnetically soft layer can be arranged between permanent magnets and coils. This magnetically soft layer can allow the magnetic field generated by the permanent magnets to concentrate locally. This has the technical advantage that less permanent magnet material is required for a local field of the same strength, which in turn saves volume and weight and thus increases the torque density.

In one aspect of the invention, the swashplate can be mechanically interlocked with both stator parts on both sides.

This allows the torque to be introduced mechanically symmetrically into the disk.

This has the technical advantage that a reduction in the mechanical stresses within the disk as well as a reduction in the forces at the bearing points of the output shaft and the transmission mechanism can be achieved. This results in components with less material, for example slimmer components, which can increase the torque density.

In an advantageous embodiment, the toothing between the disk and the stator can be designed in such a way that a single disk toothing can simultaneously engage in the counter-toothing of the upper stator part and in the counter-toothing of the lower stator part.

This can be achieved, for example, with pin teeth on the disc.

Since only one toothing is required on the disc, space and weight can be saved, which in turn increases the torque density.

In one aspect of the invention, magnetic forces in the air gap can be advantageously influenced by shaping the disk and the stator.

The reluctance force between two flat ferromagnetic bodies is highly nonlinear with the distance between the two bodies. This means that the reluctance forces near a contact point between the swashplate and stator are very high, but decrease quickly as the distance to the contact point increases.

Through clever shaping, for example a circumferential conical elevation on the swashplate and a corresponding circumferential conical groove on the stator, the distance dependence of the reluctance force can be reduced.

A different shape to optimize the air gap and the associated reduction of the distance dependence of the reluctance force is not excluded from the idea of the invention.

The air gap shaping can result in a more favorable current distribution in the coils, which in turn results in more compact coils and thus increases the torque density.

In addition, the amount of torque fluctuations during a rotating wobbling movement is reduced.

In an advantageous embodiment, two swashplates can be used, both of which are mounted on the same output shaft.

If both swashplates run anticyclically, the result is a mechanically balanced system that allows the drive to run smoothly even at high speeds.

If an additional stator is inserted between the two disks, the two disks can be controlled independently of each other. This can be used to eliminate any gear backlash.

BRIEF DESCRIPTION OF THE FIGURES

• 1 zeigt eine Explosionszeichnung eines Taumelscheibenantriebes aus dem Stand der Technik.
• 2 zeigt eine schematische Darstellung eines Taumelscheibenantriebes mit doppelseitigem Stator und Erreger-Magnetfeld aber ohne Taumelscheibe.
• 3 zeigt eine schematische Darstellung des Taumelscheibenantriebes mit doppelseitigem Stator, Erreger-Magnetfeld und Taumelscheibe.
• 4 zeigt eine schematische Darstellung des Taumelscheibenantriebes zur Verdeutlichung in perspektivischer Ansicht.
• 5 zeigt eine Taumelscheibe mit Stiftverzahnung und umlaufender Luftspaltformgebung.
• 6 zeigt einen Taumelscheibenantrieb im Schnitt, mit Permanentmagneten, Stiftverzahnung und Luftspaltoptimierung.

The invention and further embodiments and advantages of the invention are explained in more detail below with reference to figures, whereby the figures merely represent exemplary embodiments of the invention describe. The same components in the figures are given the same reference numbers. The figures are not to be viewed as true to scale; individual elements of the figures may be shown in an exaggeratedly large or oversimplified manner.

• 1 shows an exploded view of a swashplate drive from the prior art.
• 2 shows a schematic representation of a swashplate drive with a double-sided stator and exciter magnetic field but without a swashplate.
• 3 shows a schematic representation of the swashplate drive with a double-sided stator, exciter magnetic field and swashplate.
• 4 shows a schematic representation of the swashplate drive in a perspective view for clarity.
• 5 shows a swashplate with pin teeth and circumferential air gap shaping.
• 6 shows a section of a swashplate drive, with permanent magnets, pin teeth and air gap optimization.

DETAILED DESCRIPTION OF EMBODIMENTS

A swashplate drive according to the state of the art (see for example 1 ) consists of an electromagnetic stator 1 with copper coils and iron core, at least one ring gear 2 on the stator side, a swash plate 3 with teeth 4 on the swash plate, a constant velocity joint 6, an output axle with bearing 7 and a housing 5, 8 with bearing seat and torque Support.

Possible constant velocity joints would include, among others, a double cardan joint, a constant velocity joint, a bellows joint, or a Pode joint. By alternately energizing the coils of the electromagnetic stator 1, the swash plate 3 is set into a continuous, rotating wobbling movement, which results in a relative movement between the disc and the stator. This relative movement is transmitted to the axis 7 via the constant velocity joint 6. Various variations of this basic principle have been used, among other things, in the publications US 3,492,515 , DE 100 28 964 A1 , DE 1 763 078 A1 , US 10,574,109 B2 described.

A further development of the wobble drive according to the invention is shown schematically in 2 until 4 illustrated.

If the windings 11A, 11B are not energized, then the stator of the drive, consisting of windings 11A, 11B, distribution layer 10A, 10B, permanent magnet 9A, 9B and magnetic yoke 12, generates a quasi-homogeneous magnetic field 14 through the permanent magnets 9A, 9B Air gap LS.

The schematic course of the magnetic field lines 14 is in 2 shown. The generation of magnetic flux through the yoke 12 can be generated by one or more permanent magnets in the magnetic circuit. Other positions of the permanent magnets 9A, 9B, not shown, are not excluded from the inventive concept. Current-carrying windings around the yoke 12 are also possible.

If a swash plate 15 made of magnetically soft material is now introduced into the air gap LS (see for example 3 ), the magnetic field lines shift.

The axis of symmetry of the swashplate 17 must be tilted to the axis of symmetry of the drive shaft 16.

The two axes must intersect with the intersection point being in the middle of the air gap LS. This intersection point is also referred to as the swash point T.

The magnetic field lines now shift towards the smallest air gap 18A, 18B in order to optimize the energy of the entire magnetic field. The field lines emerge from the upper stator part - in the area of the upper smallest air gap 18A between the swashplate and the upper stator part - and enter - in the area of the smallest air gap 18A - into the swashplate.

The field lines then run within the swashplate to the lower smallest air gap 18B. The field lines now emerge on the opposite flat side of the swashplate and enter the lower part of the stator - in the area of the lower, smallest air gap 18B. The magnetic circuit can now close via the yoke 12.

For clarification, in 4 An exemplary magnetic field line in the three-dimensional magnetic circuit is shown again.

In order to force the swash plate 15 into a tumbling movement, the magnetic field is modulated - or locally strengthened and locally weakened - via the distribution layer 10A, 10B and the electromagnetic windings 11A, 11B.

The distribution layer 10A, 10B is merely a passive layer made of magnetically soft material, such as iron, which enables the magnetic field to dynamically concentrate or weaken locally.

The electromagnetic windings 11A, 11B can take on various designs that are known from classic axial flux machines.

Examples that should be mentioned here are the single tooth winding, the distributed winding or the ironless distributed air gap winding.

It is not relevant how many electrical phases or magnetic teeth the windings have, as long as the magnetic field can be effectively locally strengthened or weakened. Six to eight phase single tooth windings have proven to be beneficial.

In the area of the upper smallest air gap 18A, the magnetic field is now strengthened in front of the smallest air gap 18A (along the circumference) and weakened behind the smallest air gap 18A. The control on the opposite side of the swashplate is point-symmetrical to the swash point T. The swashplate now “tilts” in the direction of the strengthened field.

A further improvement to the prior art consists of a special pin toothing 19 between the stator and the swashplate 15 (see 5 ).

The pins on the swashplate 15 point radially outwards.

In addition, the axes of the pins lie on the plane which is parallel to the swash plate 15 and passes through the swash point T.

This has the advantage that the same toothing can engage both in the counter-toothing of the upper stator part 21A and also in the counter-toothing of the lower stator part 21B (see 6 ), whereby both interventions have the same radial distance from the swash point T or lie on the same cylinder surface with the axis of symmetry of the swash plate 15.

A further improvement to the prior art is an optimized air gap 22A, 22B between the stator and the swashplate in order to optimize the magnetic forces.

5 shows a circumferential, conical elevation 20. The swash plate and the conical elevation 20 are made of magnetically soft material such as iron.

The counterpart on the stator side is also made of magnetically soft material and has a circumferential conical groove or a groove interrupted by the windings.

This creates a V-shaped circumferential air gap 22A, 22B.

By changing one or more parameters of the V-shaped air gap 22A, 22B, such as angle, width, height, number, or others, the magnetic force can be optimized depending on the distance - swashplate to stator.

6 shows a swash plate drive with permanent magnets 9A, 9B, pin teeth 21A, 21B and an optimized air gap 22A, 22B.

The magnetic field generated by the permanent magnets is distributed over the upper distribution layer 10A to the individual tooth windings 11A.

In the area of the smallest air gap 18A, the field enters the swash plate, spreads along the circumference and enters the lower single-tooth windings 11B on the opposite side, again in the area of the smallest air gap 18B.

There the field is distributed again over the lower distribution layer 10B and enters the yoke 12 homogeneously via the lower permanent magnet 9B. The yoke 12, shown here as a cylindrical housing, forms the connection to the upper permanent magnet 9A.

If the windings 11A, 11B are now continuously energized in such a way that there is a field strengthening in front of the area of the smallest air gap and a field weakening behind the area of the smallest air gap 18A, 18B, the swashplate rolls continuously. It should be noted that the diagonally opposite coils must each be energized point-symmetrically to the wobble point T.

The rolling of the swashplate 15 in the teeth 21A, 21B creates a relative movement between the swashplate 15 and the stator. This movement is transmitted to the shaft 13 via the constant velocity joint 23.

The shaft is held concentrically to the cylindrical stator by the bearings 24.

REFERENCE SYMBOL LIST

1

Magnetic stator with windings and iron core

2

Mechanical gearing on the stator

3

Swashplate according to the state of the art

4

Mechanical gearing on the swashplate

5

Housing part with bearing seat and teeth

6

constant velocity joint

7

Drive axle and bearing

8th

Circumferential housing part

9A

Permanent magnet axially magnetized at the top

9B

Permanent magnet axially magnetized below

10A

Distribution layer made of magnetically soft material at the top, e.g. iron

10B

Distribution layer made of magnetically soft material at the bottom, e.g. iron

11A

Electromagnetic windings on top

11B

Electromagnetic windings below

12

Magnetic yoke

13

Mechanical shaft of the drive

14

Magnetic field line

L.S

Air gap between upper and lower stator parts

15

Swashplate made of magnetically soft material, e.g. iron

16

Axis of symmetry of the drive shaft

17

Axis of symmetry of the swashplate

T

swash point

18A

Area of the smallest air gap at the top

18B

Area of the smallest air gap at the bottom

19

Pin teeth on swashplate

20

Circumferential cone-shaped elevation made of magnetically soft material

21A

Counter-toothing on the upper stator part

21B

Counter-toothing on the lower stator part

22A

V-shaped all-round air gap at the top

22B

V-shaped all-round air gap at the bottom

23

constant velocity joint

24

storage

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was 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

• US 3492515 [0002, 0042]
• DE 10028964 A1 [0002, 0042]
• DE 1763078 A1 [0002, 0042]
• US 10574109 B2 [0002, 0042]

Claims (10)

An electromagnetic swash plate drive, comprising a swash plate (15), characterized in that a magnetic field enters on a first flat side of the swash plate (15), propagates through the swash plate (15), and on the opposite second flat side of the swash plate (15 ) emerges again, with the conclusion of the magnetic field taking place outside the swashplate. The swashplate drive after Claim 1 , characterized in that the magnetic field occurs in the area of a first smallest air gap (18A) between the swash plate (15) and a stator and the magnetic field occurs again in the area of a second smallest air gap (18B) between the swash plate (15) and the stator exits, the areas of the two smallest air gaps (18A, 18B) each being on the opposite side of the swash plate (15) and point-symmetrical to the swash point (T). The swash plate drive according to one of the preceding claims, characterized in that the magnetic field is at least partially generated by at least one permanent magnet (9A, 9B) in the non-movable part of the drive. The swash plate drive according to one of the preceding claims, characterized in that a magnetically conductive distribution layer (10A, 10B) is arranged between the permanent magnet (9A, 9B) and the swash plate (15). The swashplate drive after Claim 4 , characterized in that one or more electrically conductive windings (11A, 11B) lie between the swash plate (15) and the distribution layer (10A, 10B), the windings (11A, 11B) and the distribution layer (10A, 10B) being fixed Part of the drive. The swashplate drive according to one of the previous ones Claims 3 until 5 , characterized in that the magnetic field generated by the permanent magnets (9A, 9B) is weakened by the electromagnetic windings (11A, 11B) in front of the area of the smallest air gap (18A, 18B) and behind the area of the smallest air gap (18A, 18B) is reinforced in order to force the swash plate (15) into a continuous wobbling movement, with the windings (11A, 11B) being controlled point-symmetrically to the wobble point (T). A swash plate drive, comprising a swash plate (15), characterized in that a single toothing (19) is arranged on the swash plate (15), which at the same time fits into a mating toothing on a first stator part (21A) and a mating toothing on a second stator part (21B ). The swashplate drive after Claim 7 , characterized in that the toothing (19) on the swashplate (15) is carried out by cylindrical pins which are aligned in the radial direction, the axis of the pins lying on a plane which is parallel to the swashplate (15) and through the swash point (T). A swash plate drive, comprising a swash plate (15), characterized in that an air gap (22A, 22B) between a stator and the swash plate (15) is designed such that the distance dependence of the magnetic reluctance force between the swash plate (15) and the stator is reduced becomes. The swashplate drive after Claim 9 , characterized in that a circumferential elevation (20) or depression is arranged in the swashplate (15) and the negative of the circumferential elevation or depression is arranged in the stator, so that there is a V-shaped air gap (22A, 22B) between the swashplate (15) and Stator results.

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