DE102008001041A1 - Shaft device i.e. transmission such as worm gear- transmission, for use in automobile, has magnet arranged such that entire force caused by magnet has portion that acts radial to shaft, where portion increases friction force in bearing - Google Patents

Abstract

The device (10) has a shaft (20) rotatably supported around an axis of the shaft in a bearing (22), and a magnet (30) movable in a limited area opposite to the bearing. The magnet is arranged in such a manner that the entire force caused by the magnet has a portion that acts radial to the shaft, where the portion increases the friction force in the bearing. A set of magnets are fastened at the shaft and movable in a limited area opposite to the shaft. The magnets are formed as ring or permanent magnets.

Description

Technical area

The The present invention relates to a wave device, for example a transmission that includes an electric motor or another engine or is designed for coupling to a motor.

State of the art

Electric motors, Ultrasonic motors and other engines are becoming more diverse Way to operate, move or adjust mechanical Facilities used. To be high or at least sufficient Efficiency, low production costs, the lowest possible Dimensions and as large as possible mechanical Robustness the required force or torque, the necessary travel and the desired positioning times Realizing it often becomes a relative one fast running engine and a reduction gearbox combined. Application examples in the automotive industry are windows, Seat adjustment and the adjustment of steering columns, rear-view mirrors, Etc.

at Many applications should also without a power supply to the motor Ensure that a force or torque on the output the transmission causes no adjustment or movement. A controllable Braking or locking usually gets extra Cost of manufacture, maintenance and control and a increased risk of failure. For this reason, worm gears and other self-locking gear widely used.

The DE 103 45 867 A1 describes a device for clamping two rotatably mutually supported parts, in which by means of an axial magnetic field, a component of a magnetostrictive material is deformed to produce frictional engagement between two surfaces.

In the DE 103 24 966 A1 describes a gear for a transmission of an electric motor drive, in which a toothing is formed at a position of a material with increased static and / or sliding friction to increase a self-locking of the transmission.

The EP 1 369 319 A2 describes a servomotor for motor vehicle functional parts with a self-locking transmission. An intermediate disc of the transmission has a material with a non-linear coefficient of friction.

In the DE 101 25 836 A1 describes a DC motor with permanent magnets and a disc-shaped anti-rotation element in the magnetic field of the permanent magnet of the motor.

disadvantage said conventional devices are under other in an increased design effort and a poor adaptability to the requirements of a specific application.

A Object of the present invention is an improved Shaft device, such as a gearbox, to create the an unwanted adjustment difficult.

Disclosure of the invention

These Task is by wave devices according to the solved independent claims.

further developments are indicated in the dependent claims.

The The present invention is based on the idea, in the vicinity a wave one or more magnets to be arranged so that by Interaction of the magnet or magnets with the shaft in the shaft is held at least one angular position, for example by a friction between the shaft and a bearing increases becomes. If the shaft at the same time the shaft of an electric motor is the magnet or are the magnets not the stator magnets of the magnet Electric motor, but designed as a separate magnet.

One Advantage of at least part of the embodiments is common, is that an inhibitory effect, which is an unintentional Rotation of the shaft prevents or impedes, independently can be formed by a motor driving the shaft. The present invention can therefore also be used when on the shaft, for example, no electric motor or no electric motor provided with a stator magnet designed as a permanent magnet is. The present invention is thus also, for example, with a three-phase or ultrasonic motor or in a configuration, when the shaft is not at the same time shaft of a drive motor is, usable.

For example, the shaft may be part of a worm gear or other gearbox. An induced by the magnet or the inhibition of rotation of the shaft, for example, in cooperation with a caused by frictional forces in a worm gear self-locking of the transmission cooperate particularly advantageous at the same time a sufficient inhibitory effect and compared to conventional operating devices with self-locking gear improved efficiency to achieve.

at An embodiment comprises a shaft device a bearing, a shaft rotatably mounted in the bearing about its axis and one or more first magnets arranged so that they do not face the camp or at least in terms of a rotation about the axis of the shaft only in a limited Area are movable. The one or more magnets are arranged so that one caused by the one or more first magnets Total force on the shaft a radially acting to the shaft portion has, which increases a frictional force in the bearing.

The Wave has, for example, a magnetizable or magnetized Material on. Alternatively or additionally one or more second magnets so attached to the shaft, that they are not or at the most are movable within a limited angular range. The poles of the first magnet (s) and the second magnet (s) are advantageously arranged so that in one or more Angular positions of the shaft on a first side of the shaft respectively attracting poles of the first and second magnets and on a second, in particular opposite, side of Wave each repulsive poles of the first and second Magnets face each other. Attractive interactions between one or more poles of the first magnet or magnets and one or more poles of the second magnet (s) the first page and repulsive interactions between one or more poles of the first magnet (s) and one or more magnets a plurality of poles of the second magnet or magnets on the second side add up to a total force with a radially acting to the shaft Proportion of. This radial portion increases the effect between opposite bearing surfaces of the bearing and the wave stored in it. This effect can be increased Be as close as possible by the one or more magnets the bearing are arranged.

at a variant is a lubricant film between each other Bearing surfaces of the bearing and the shaft mounted therein arranged. When the shaft rests, displaces the radial portion the total force the lubricant film locally as far (partially or complete) that increases the friction in the bearing becomes. When the shaft rotates, the lubricant film becomes again manufactured in its nominal thickness and the friction in the bearing accordingly reduced.

One another embodiment of a shaft device comprises a drive motor, a bearing, one or more first magnets, a rotatably mounted in the bearing about its axis shaft and a or a plurality of separate from the drive motor second magnet. Of the or the first magnets are arranged facing each other the warehouse or at most within a limited Area are movable. The second magnet (s) are on the shaft arranged that they are not facing the shaft or at most within a limited range are movable. Poles of the first and second magnets are arranged that in at least one angular position of the shaft each other opposite poles of the first and second magnets put on each other. The drive motor is for example an electric motor, wherein the shaft can be the shaft of the electric motor at the same time.

By the separate from the drive motor training of the first and second Magnets, a standard drive motor can be used unmodified. At the same time, the inhibiting or holding effect of the first and second magnets in the at least one angular position with respect to the angular position or positions, the number of angular positions, in which the inhibiting or holding effect occurs, and in terms the amount of inhibitory or holding effect regardless of the drive motor used readily for any Applications are optimized.

Especially Advantageously, an arrangement of the poles of the first and second Be magnet such that one of the interaction of opposing poles resulting torque is at a maximum angular position, in which a cogging torque of the drive motor is maximum. The cogging torque of the drive motor is due to the interaction between the stator and rotor of the drive motor without power supply occurring angle-dependent Torque.

One Another embodiment of a shaft device comprises a bearing, one or more first magnets, one in the bearing about its axis rotatably mounted shaft which can be coupled to a drive motor, but not at the same time is the shaft of a drive motor, and one or more second magnets. The one or more first Magnets are not or at most opposite the bearing movable within a restricted range. The one or the plurality of second magnets are opposite the shaft not or at most within a limited Area movable. The poles of the first and second magnets are arranged so that in at least one angular position of the shaft respectively opposite poles of the first and tighten the second magnet.

In the two last-mentioned embodiments, the first and second magnets or their poles are arranged, for example, so that one exerted by all the first and second magnets Total force on the shaft in all angular positions is substantially zero or at least has a substantially vanishing radial component. In all embodiments, the first and second magnets may each be formed as a ring magnet and / or as a permanent magnet.

Brief description of the figures

following Be embodiments of the invention with reference to the accompanying Figures explained in more detail. Show it:

1 a schematic representation of a shaft device;

2 a schematic representation of a part of in 1 Shaft device shown;

3 a schematic representation of another wave device; and

4 a schematic representation of part of a further shaft device.

Description of the embodiments

1 shows a schematic representation of a wave device 10 with a rotor 12 with armature windings and a commutator 14 on a wave 20 , The rotor 12 and the commutator 14 are parts of an electric motor whose other components are in 1 are not shown. The wave 20 is rotatable about its axis in a first bearing 22 and a second camp 24 stored. Camps 22 . 24 each have a lubricant film in this example 26 between each opposite bearing surfaces of the shaft 20 and the camp 22 . 24 on. At the wave 20 is a worm wheel 28 arranged with an in 1 not shown further gear can form a worm gear. Near the first camp 22 is a first magnet 30 arranged so that its magnetic field up to the shaft 20 enough. The first magnet 30 points one of the shaft 20 facing pole 32 on that in 1 marked with an "S". At one of the wave 20 opposite side has the first magnet 30 another pole on, in 1 marked with an "N".

As poles of a magnet areas of the surface of the magnet are usually referred to, in which the magnetic flux density has a global or at least a local maximum. When the magnetic field is represented by field lines, the poles of a magnet are the areas on the surface of the magnet with a high density of field lines. As a rule, a distinction is made between north and south poles, which are identified by an "N" or "S". Since in this case a pole 32 of the first magnet 30 the wave 20 is facing, the magnetic flux density at the location of the shaft 20 larger than in an alternative configuration, where neither of the two poles of the magnet 30 the wave 20 is facing.

The wave 20 has a magnetizable or paramagnetic material, for example a magnetizable steel. In the magnetic field of the first magnet 30 becomes the magnetizable material of the shaft 20 magnetized and from the first magnet 30 dressed. This results in a force on the shaft 20 which are substantially radial or perpendicular to the axis of the shaft 20 is directed. This force increases at the first magnet 30 facing side of the first bearing 22 the surface normal force and thus also the frictional force between each other and only through the lubricant film 26 separate bearing surfaces of the shaft 20 and the camp 22 ,

This increased frictional force in the first bearing 22 reduced or prevented - especially in conjunction with a self-locking gear, as by the worm wheel 28 is indicated - in the de-energized case or without power supply for by the rotor 12 and the commutator 14 indicated electric motor the likelihood that one over the worm wheel 28 on the wave 20 acting torque is a rotation of the shaft 20 entails.

When the wave 20 , driven by the electric motor passing through the rotor 12 the commutator 14 is indicated, rotated, the surface normal force and the frictional force in the bearing 22 opposite the case of the resting wave 20 be reduced by various effects. In addition to the mass inertia of the shaft 20 Contribute that material to the shaft 20 can not be magnetized or re-magnetized arbitrarily fast. Therefore, as the rotational frequency increases, the effective magnetization of the shaft decreases 20 and the attraction between the first magnet 30 and the wave 20 , Another contribution is the lubricant film 26 Afford. When the wave 20 rests, the lubricant film can 26 locally partially or completely displaced by the radial force or surface normal force between the opposite bearing surfaces, whereby the friction-reducing effect of the lubricant is reduced and the friction increases. When the wave 20 in stock 22 rotates, the lubricant film is made at least approximately in its nominal thickness again due to its viscosity, and the friction decreases.

The effects described have the consequence that the friction or the rotational resistance of the rotational frequency of the shaft 20 dependent and at a standstill of the shaft 20 is significantly higher than at a fast rotation of the shaft 20 , Thus, on the one hand, a high mechanical efficiency is achieved when the shaft 20 driven or by the rotor 12 and the commutator 14 driven electric motor is supplied with electrical power. On the other hand, a high rotational resistance of the shaft 20 or a large inhibitory effect achieved when the shaft 20 not driven or by the rotor 12 and the commutator 14 indicated electric motor is not supplied with electrical power.

2 shows a schematic representation of part of the above based on the 1 illustrated shaft device or an enlarged section 1 , In addition to the above based on the 1 shown features are in 2 in the direction parallel to the axis of the shaft 20 measured axial distance X between each other in the axial direction opposite side surfaces of the first bearing 22 and the first magnet 30 as well as in the direction perpendicular to the axis of the shaft 20 measured radial distance Y between the lateral surface of the shaft 20 and that of the wave 20 facing pole 32 of the first magnet 30 shown.

Because the first magnet 30 between the first camp 22 and the second camp 24 is arranged, the radial portion of the first magnet 30 on the wave 20 applied force on the two bearings 22 . 24 divided up. The closer the first magnet 30 at the first camp 22 is arranged, or the smaller the axial distance X between the first bearing 22 and the first magnet 30 is, the larger are those in the first camp 22 generated surface normal force and the resulting friction. The smaller the radial distance Y between the shaft 20 and the first magnet 30 is, the larger are those of the first magnet 30 at the place of the wave 20 generated magnetic flux density, the resulting magnetization of the wave 20 and the resulting attractive force between the first magnet 30 and the wave 20 , For these reasons, an arrangement of the first magnet with the smallest possible axial distance X from the first bearing 22 and especially with the least possible radial distance Y from the shaft 20 advantageous.

Instead of a magnetizable or paramagnetic material, the shaft 20 a permanent magnetic material or a ferroelectric material having high coercive force. The magnetization of the wave 20 will then, unlike above based on the 1 and 2 represented, not or only partially by the magnetic field of the first magnet 30 affected. In this case, the radial portion of the first magnet 30 on the wave 20 applied force and thus the surface normal force in the camp 22 and the friction occurring there from the angular position of the shaft 20 dependent. When the wave 20 rotated at a rotational frequency, the radial portion of the oscillate through the first magnet 30 on the wave 20 applied force, the surface normal force and the friction in the first bearing 22 with the rotation frequency. One consequence is that the friction is maximal in a certain angular position. Another possible consequence is that the wave 20 preferably stops in the vicinity of this angular position. The oscillating surface normal force can be the formation of a lubricant film and thus a reduction of the friction with a rotating shaft 20 favor.

3 shows a schematic representation of a wave device 10 that differ from the above based on the 1 and 2 illustrated shaft device and the variants described differs in that two first magnets 30 and a second magnet 40 are provided. The first two magnets 30 are related to the wave 20 or their axis opposite each other. In other words, the first two magnets are located 30 with the axis of the shaft 20 approximately in one plane, with the shaft 20 between the first two magnets 30 is arranged. The second manget 40 is designed as a ring magnet, which is the shaft 20 between the first camp 22 and the worm wheel 28 annularly encloses and rigid or immovable with the shaft 20 connected is.

In the in 3 illustrated angular position of the shaft 20 and the second magnet 40 lie on the in 3 above shown two attracting poles 32 . 42 of the first magnet 30 and the second magnet 40 opposite each other while on the opposite, in 3 bottom side shown two mutually repulsive poles 34 . 44 of the first magnet 30 and the second magnet 40 opposite each other. The repulsive force between the repulsive poles of the same name 34 . 44 acts on the wave 20 in the same direction as the attractive force between the dissimilar poles attracting one another 32 . 42 , The above based on the 1 and 2 shown effects and friction in the first camp 22 are reinforced by it.

Notwithstanding the above illustration with reference to 3 can have a larger number of first magnets 30 be provided. Further, instead of two or more first magnets 30 an annular or approximately annular or in the form of a part of a ring formed first magnet may be provided. Furthermore, notwithstanding the above representation based on the 3 instead of an annular second magnet 40 several individual second magnets 40 on the shaft 20 be arranged and connected to this rigid or immovable.

In each of the variants of the above based on the 3 Shaft device shown, it is advantageous if the number of the shaft 20 associated poles 32 . 34 of the first magnet (s) 30 the number of the first magnet 30 facing poles 42 . 44 of the second magnet or magnets 40 equivalent. Furthermore, it is advantageous if there is at least one angular position of the shaft 20 there, at each of the wave 20 facing pole 32 . 34 of the first magnet (s) 30 a pole 42 . 44 of the second magnet or magnets 40 opposite. It is particularly advantageous if the poles 32 . 34 . 42 . 44 are arranged so that on one side of the shaft 20 , in particular within an angular range of about 180 degrees, mutually attracting poles face each other, while on the opposite side, in particular within the remaining angular range, repulsive poles face each other.

4 shows a schematic representation of a part of a further wave device, for example, as the above with reference to 1 to 3 Shaft means shown a shaft 20 has, which is rotatably mounted in one or more bearings about their axes. The representation in 4 shows a section along a plane perpendicular to the axis of the shaft 20 stands. Similar to the above based on the 3 Shaft means shown is on the shaft 20 an annular second magnet 40 arranged with the shaft 20 rigidly or immovably connected. Concentric to the wave 20 and the second magnet 40 is a ring-shaped first magnet 30 arranged. The first magnet 30 and the second manget 40 have opposite poles 32 . 34 . 42 . 44 on. The poles 32 . 34 . 42 . 44 the first and second magnets 30 . 40 are arranged so that at least in the in 4 illustrated angular position of the shaft 20 every pole 32 . 34 of the first magnet 30 an unlike and attractive pole 42 . 44 of the second magnet 40 opposite. For this purpose, the first magnet 30 and the second magnet 40 in particular in each case an equal number of poles and preferably in each case an even number of poles. Furthermore, it may be advantageous, as in 4 represented, the poles 32 . 34 . 42 . 44 to arrange so that the distances measured in the circumferential direction and the angular distances of the poles 32 . 34 of the first magnet 30 are equal to each other and measured in the circumferential direction distances or angular distances of the poles 42 . 44 of the second magnet 40 are equal to each other.

When the poles 32 . 34 of the first magnet 30 with each other substantially the same strengths and the poles 42 . 44 of the second magnet 40 have substantially equal thicknesses to each other and the angular distances between the poles are equal, lift the radial portions of the forces acting between the opposing poles forces at all angular positions of the shaft 20 essentially on each other. Unlike the above based on the 1 to 3 Shaft means shown have the first and second magnets 30 . 40 thus in no angular position of the shaft 20 an increased surface normal force and increased friction in a bearing result. Instead, an arrangement of poles, as based on the 4 was described, one on the shaft 20 acting torque, its magnitude and direction as a function of the angular position of the shaft 20 oscillate. The wave 20 Therefore, similar to the shaft of an electric motor with permanent magnets, it engages in certain angular positions. When the in 4 Shaft is connected to an electric motor, the angular positions can be chosen so that the locking action of the electric motor and the locking action of the basis of 4 illustrated arrangement of the poles 32 . 34 . 42 . 44 add up. Conversely, an arrangement of poles 32 . 34 . 42 . 44 as they are based on the 4 has been shown, with a suitable choice of the angle also suitable to neutralize the locking action of an electric motor.

Notwithstanding the above based on the 4 illustrated arrangement may instead of an annular first magnet 30 several separate first magnets 30 and / or instead of an annular second magnet 40 several separate second magnets 40 be provided.

The waves 20 the above based on him 1 to 4 Shaft means shown can, as in the 1 to 3 at the same time be the shaft of a E lektromotors or another drive motor. Alternatively, the wave 20 be configured to be coupled to a drive motor. In both cases, however, the first and second magnets are 30 . 40 not components of the electric motor, but separately formed from this. The wave 20 can each as already based on the 1 to 3 shown coupled to a worm wheel. The wave 20 is in this case, for example, a drive shaft of a worm gear, which further comprises a coupled to an output shaft gear, which is connected to the worm wheel 28 is engaged. The shaft devices illustrated above may in this way be transmissions for window regulators, seat or mirror adjustments or other applications on automobiles or outside of automotive technology. As a material for a housing of such a gear come next to plastic, aluminum or other non-ferrous metals, other non-magnetizable metals or non-metals into consideration. If the housing itself is magnetizable or even permanent magnetic, the one or more magnets may be 30 be integrally formed with the housing.

Instead of the above based on the 3 and 4 illustrated arrangement of the second magnet 40 directly on the shaft 20 The second magnet (s) may also be indirectly connected to the shaft 20 be connected. For example, the second magnets 40 be connected to a disk that is connected to the shaft 20 connected is.

At all above based on the 1 to 4 illustrated cases, the first magnet 30 opposite the camp 22 fixedly arranged and the second magnets 40 opposite the wave 20 be arranged stationary. Alternatively, the first magnets 30 opposite the camp 22 movable in a limited range, in particular within a limited angular range. For example, the first magnets 30 about springs or other elastic elements with the bearing 22 or another immovable or fixed device. Furthermore, alternatively or additionally, the second magnets 40 opposite the wave 20 be movable in a restricted area, in particular within a limited angular range. For example, the second magnets 40 via springs or other elastic elements with the well 20 be connected.

Instead of the arrangements shown above, in which opposite poles always face each other in the radial direction, an arrangement is possible in which opposite poles face each other in the axial direction or in a direction which has both an axial and a radial portion. An advantage of such an arrangement may be that the space requirement in the radial direction is reduced. Another advantage may be that the one or more magnets 30 and the second magnet or magnets 40 can be identical.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10345867 A1 [0004]
• - DE 10324966 A1 [0005]
• - EP 1369319 A2 [0006]
• - DE 10125836 A1 [0007]

Claims (13)

Wave device ( 10 ) with: - a warehouse ( 22 ); - one in the warehouse ( 22 ) shaft rotatably mounted about its axis ( 20 ); - one or more opposite the warehouse ( 22 ) at most in a limited range movable first magnet ( 30 ), wherein the one or more magnets ( 30 ) are arranged so that one through the one or more first magnets ( 30 ) caused total force on the shaft ( 20 ) one radially to the shaft ( 20 ) that has a frictional force in the bearing ( 22 ). Wave device ( 10 ) according to the preceding claim, in which the shaft ( 20 ) comprises a magnetizable material or a magnetized material. Wave device ( 10 ) according to one of the preceding claims, further comprising one or more second magnets ( 40 ) on the shaft ( 20 ) and opposite the shaft ( 20 ) are movable at most in a limited angular range. Wave device ( 10 ) according to the preceding claim, in which poles ( 32 . 34 . 42 . 44 ) of magnets ( 30 . 40 ) are arranged so that in at least one angular position of the shaft ( 20 ) on one side of the shaft ( 20 ) attracting poles ( 32 . 42 ) of the first and second magnets ( 30 . 40 ) are opposite each other and on another side repelling poles ( 34 . 44 ) of the first and second magnets ( 30 . 40 ) face each other. Wave device ( 10 ) according to one of the preceding claims, in which the bearing ( 22 ) a lubricant film ( 26 ), characterized by the radial portion of the total force at least when the shaft ( 20 ) is displaced so far that the friction in the bearing ( 22 ) is increased. Wave device ( 10 ) with: - a drive motor ( 12 . 14 ); - a warehouse ( 22 ); - one or more opposite the warehouse ( 22 ) movable within a limited range at the most and by the engine ( 12 . 14 ) separate first magnet ( 30 ), - one in the warehouse ( 22 ) shaft rotatably mounted about its axis ( 20 ); - one or more opposite the shaft ( 20 ) at most in a limited range and by the drive motor ( 12 . 14 ) separate second magnet ( 40 ), where poles ( 32 . 34 . 42 . 44 ) of the first and second magnets ( 30 . 40 ) are arranged so that in at least one angular position of the shaft ( 20 ) each opposite poles ( 32 . 34 . 42 . 44 ) of the first and second magnets ( 30 . 40 ) attract each other. Wave device ( 10 ) according to the preceding claim, wherein the drive motor ( 12 . 14 ) is an electric motor; and the poles ( 32 . 34 . 42 . 44 ) are arranged so that one of the interaction of opposing poles ( 32 . 34 . 42 . 44 ) resulting torque at an angular position is maximum at which a cogging torque of the drive motor ( 12 . 14 ) is maximum. Wave device ( 10 ) with: - a warehouse ( 22 ); - one or more opposite the warehouse ( 22 ) at most in a limited range movable first magnet ( 30 ), - one in the warehouse ( 22 ) shaft rotatably mounted about its axis ( 20 ), which are powered by a drive motor ( 12 . 14 ) can be coupled; - one or more opposite the shaft ( 20 ) at most in a limited range movable second magnet ( 40 ), where poles ( 32 . 34 . 42 . 44 ) of the first and second magnets ( 30 . 40 ) are arranged so that in at least one angular position of the shaft ( 20 ) each opposite poles ( 32 . 34 . 42 . 44 ) of the first and second magnets ( 30 . 40 ) attract each other. Wave device ( 10 ) according to one of claims 6 to 8, in which a radial component of one of all the magnets ( 30 . 40 ) applied total force on the shaft ( 20 ) is substantially zero in all angular positions. Wave device ( 10 ) according to one of the preceding claims, in which at least one of the first magnets ( 30 ) or the second magnet ( 40 ) is a ring magnet. Wave device ( 10 ) according to one of the preceding claims, in which at least one of the first magnets ( 30 ) or the second magnet ( 40 ) is a permanent magnet. Wave device ( 10 ) according to one of the preceding claims, wherein the wave device ( 10 ) is or includes a transmission. Wave device ( 10 ) according to the preceding claim, further comprising a worm wheel ( 28 ) on the shaft ( 20 ).