DE102008035609A1 - Drive device has housing and motor with low moment of inertia arranged in housing, and another motor has high torsional moment arranged in housing, where rotors of both motors are connected with each other - Google Patents

Abstract

The drive device has housing (1) and a motor (5) with low moment of inertia arranged in the housing. Another motor (8) has high torsional moment arranged in the housing, where the rotors (7,10) of both the motors are connected with each other by a coupling device (12) in a force-fit manner. The motors are arranged around a motor shaft (4), where one motor is directly connected with the motor shaft and other motor is rotatably supported on the motor shaft.

Description

The The invention relates to a drive device with a housing and two motors disposed in the housing. such Drive devices can be used, for example a spool of a pilot operated hydraulic multi-way valve be used.

permanent magnet Excited electric motors usually consist of a rotor, the from a permanent magnetic material with as possible high coercive field strength and the highest possible remanent magnetic flux is produced. The rotor is considered a cylinder shaped, which is rotatably mounted about the axis of symmetry of the motor.

The Bearing rod transmits during operation in the engine generated torque to the driven load. Axial, tilt and Transverse forces are intercepted by two bearing points, the are arranged above and below the rotor. The design of this Bearing is selected according to whether axial or radial forces predominate.

The Poles of the permanent magnet are radially oriented; the vector of magnetic flux density, except in peripheral areas, no component pointing in the axial direction. By special poling method can be strip-shaped on the cylindrical surface of the anchor Magnetizations are generated. The permanent magnet shows at the Surface 2n equal width strips, one strip of which represents magnetic south pole and the two adjacent Strip a north pole. This creates a periodic around the anchor Magnetic field off; the field distribution looks like a rotation of the Ankers around 360 ° / n again the same.

Of the Anchor runs out of a pile in a cage soft magnetic sheets. These sheets and coils form together with the poles of the armature magnet one or more magnetic circuits. These Magnetic circuits are created by superposition of the permanent Magnetic flux with the magnetic flux generated by the excitation of the coils.

Of the Motor tries the energy stored in these magnetic circuits minimize by the rotor in an energetically favorable Situation turns. The derivation of the magnetic energy according to the angle of rotation corresponds to the torque at the bearing rod.

From the DE 101 47 073 A1 is an electronically commutated DC motor with coaxially arranged to a longitudinal axis of the electric motor stator and rotor known. The stator has a plurality of electric stator poles and a plurality of phase windings. The rotor has a permanent magnet with magnetic pole pairs, which are assigned to the phase windings. The phase windings and / or the permanent magnet are divided in the direction of the longitudinal axis of the electric motor into a plurality of axial sections, and these sections are rotated about the longitudinal axis of the electric motor against each other. By the engine after the DE 101 47 073 A1 the angular position of the individual phases is canceled each other such that the torque ripple can be reduced and torque gaps can be avoided.

In the DE 298 24 616 U1 is an electronically commutated DC motor described having an air gap, on both sides of this air gap equiaxed, permanent magnetic rotors, which bearing assemblies are assigned, and having a arranged in the air gap stator winding, which is common to both rotors and serves to drive both rotors, wherein an axial biasing force is generated on the two bearing assemblies by the magnetic train between the permanent magnets of the two rotors.

From the DE 197 04 504 A1 For example, an electric motor is known which is divided into two subunits of the same type but different operating characteristics to accommodate different power requirements. The subunits are operated in parallel and regulated separately. The division into subunits can take place in that for each phase, the winding is divided into a base load winding and a dynamic winding, wherein the part windings differ from each other in terms of their inductance or operated differently for the same inductance.

at The design of engines is the development in conflict between Torque and dynamics. When the torque requirement at the output For example, changes in load fluctuations, the excitation current quickly changed at the most constant speed possible before the speed drops. When the speed is on a changing setpoint should be adjusted the armature are subjected to a high spin.

the stand the magnetic inertia of the iron circle and the mechanical moment of inertia of the armature against. The magnetic Inertia of the iron circuit is due to the inductance described an excitation coil, which is proportional to the anchor diameter is square and depends on the number of coil windings. The moment of inertia of the armature is proportional to the density of the permanent magnet material and the fourth power of the armature diameter.

In order to can be either high torque motors, but lower Dynamics or engines with high dynamics and low power interpret.

in principle the conflict described above is not solvable. Many many Drive tasks require a low at high speeds Torque on the drive axle (overdrive, overdrive). Indeed should the high, relatively constant speed be reached quickly, but can also be slowed down quickly. At low Speeds often require high torques, for example to accelerate a large mass to constant speed or slow down in a controlled manner. Especially at zero speed you sometimes need a holding force to a mechanical Press system into a stop.

The Invention is based on the task of a drive device of The aforementioned type such that they at low Speeds to transmit a large torque and to allow high angular acceleration at high speeds can.

The The object is achieved according to the invention that in the housing a first motor with a low moment of inertia and a second high torque motor and a coupling device are, by means of which the rotors of both engines with each other frictionally are connectable.

Thereby is achieved that at low speeds a large Torque can be transmitted and at high speeds allow high angular acceleration.

It has proved to be advantageous when the coupling device at low speeds, the rotors of both engines with each other positively connects. This will be the second engine switched on, so that a high torque is available. At higher speeds, it is decoupled, so that the first engine with low moment of inertia for high Speeds can provide.

One Bearing can be saved if both engines have a common Motor shaft are arranged, with one of the motors directly to the motor shaft connected and the other motor on the common motor shaft rotatable is stored.

In Advantageously, the coupling device of the two motors a freewheel and a pressure element, wherein the pressure element a coil spring or a plate spring can be.

alternative can according to the invention, the coupling device the two engines have a centrifugal clutch.

It has proven to be advantageous when the stators of the two Engines in the axial direction are stacked on each other, that they have a common axis of symmetry, wherein the rotor the first motor can be rigidly connected to the bearing rod, wherein the rotor of the second motor rotatably disposed about the bearing rod can be and depending on the required speed and the applied load via a coupling device the two rotors are positively connected with each other can be.

According to the invention the first motor has a first rotor with a low moment of inertia and have a first coil winding with low inductance, wherein the first rotor with a low moment of inertia a have small rotor diameter and made of a magnetic material can exist with small saturation flux density and where the first coil winding with low inductance a small one Number of turns may have.

In Advantageously, the second motor can be a rotor with a high torque and a coil winding with high inductance wherein the high torque rotor has a large rotor diameter and of a magnetic material having a high saturation flux density can exist and according to the invention, the coil winding have a high number of turns with high inductance can.

According to the invention the two motors brushless, with permanent magnets excited DC motors be.

The Drive device according to the invention a achieve high smoothness and high speed stability, if sensors are provided, the load and speed fluctuations detect and by means of a control loop on the rotating field of the first Coil winding for compensation of load and speed fluctuations act.

The Invention is described below with reference to the drawing Embodiments explained in more detail. Show it:

1 a first embodiment of a drive device according to the invention with a centrifugal clutch as a coupling device, and

2 A second embodiment of a drive device according to the invention with a freewheel coupling device.

In the 1 is a drive device with a housing 1 shown in two camps 2 and 3 a bearing rod or motor shaft 4 rotatably holding. In the tapered, first area of the housing 1 is a first engine 5 low moment of inertia and high RPM (high RPM) with a first coil winding 6 and a first rotor 7 arranged rigidly (directly) with the motor shaft 4 connected is.

In a second area of the housing 1 is a second engine 8th with high torque at low speed (low RPM) with a second coil winding 9 and a second rotor 10 arranged. The second rotor 10 is by means of a rotor bearing 11 rotatable with the motor shaft 4 connected. Between both engines 5 and 8th is a centrifugal clutch 12 arranged, which at a certain speed both rotors 7 and 10 connects together positively. Below the certain speed are due to the centrifugal clutch 12 both engines 5 and 8th connected to each other, so that the second engine 8th with high torque at low speed can muster the full force. If, however, the due to the structure of the centrifugal clutch 12 certain speed exceeded, both engines 5 and 8th decoupled, leaving the first engine 5 provides low moment of inertia for the required high speed of the drive device.

The two engines 5 and 8th may be brushless DC motors excited by permanent magnets.

In the 2 is a second drive device with the housing 21 shown in two camps 22 and 23 the motor shaft 24 rotatably holding. In the tapered, first area of the housing 21 is the first engine 25 with low moment of inertia and high speed with the first coil winding 26 and a first rotor 27 arranged directly on the motor shaft 24 is appropriate.

In a second area of the housing 21 is the second engine 28 high torque at low speed with its second coil winding 29 and its second rotor 30 arranged. The second rotor 30 is by means of a rotor bearing 31 rotatable with the motor shaft 24 connected. Between both engines 25 and 28 is a freewheel 32 arranged when driving the second motor 28 both rotors 27 and 30 connects together positively. Indicates the drive of the first motor 25 a higher speed, gives the freewheel 22 this free, so first engine 25 can provide the required high speed of the drive device with low moment of inertia, while the second motor 28 can be set still.

A compression spring 33 rests on the housing 21 in the area of the second camp 23 and pushes the second rotor 30 against the freewheel 32 and the first rotor 27 , Between compression spring 33 and second rotor 30 is a spring decoupling 34 intended.

The compression spring 33 can, as shown, be a coil spring or alternatively a plate spring.

The Drive device, for example, to control a spool a pilot operated hydraulic multi-way valve can be used.

The problem described above is achieved by the combination according to the invention of at least two motors excited by permanent magnets 5 . 8th or 25 . 28 solved. One of these two engines 5 . 8th or 25 . 28 has a designed for high speed first rotor 7 . 27 with low moment of inertia (small rotor diameter, magnetic material of low saturation flux density) and a first coil winding 6 . 26 with low inductance (few turns). The second engine 8th . 28 generates a high torque with a second rotor 10 . 30 with large rotor diameter and magnetic material of high saturation flux density and a second coil winding 9 . 29 with many turns.

This is achieved in that the two stators are stacked in the axial direction, so that they have a common axis of symmetry that the first rotor 7 . 27 of the first engine 5 . 25 rigid with the bearing rod or motor shaft 4 . 24 connected is that the second rotor 10 . 30 of the second engine 8th . 28 around the motor shaft 4 . 24 is rotatably arranged and that depending on the requested speed and the applied load via a coupling or Kopp treatment device 12 . 32 the two rotors 7 . 10 or 27 . 30 can be positively connected with each other.

With this constructive design of the two engines 5 . 8th or 25 . 28 At low speeds and high torque demand in both coil systems can generate a magnetic rotating field, which rotates synchronously in the stators and both rotors 7 . 10 or 27 . 30 go along.

little one Load and speed fluctuations can be determined by means of suitable Sensors are detected and by a fast control loop, which acts only on the rotating field of the first stator, compensated become. The drive device thus has a high level of quietness and can achieve high speed stability.

At high speeds you can both rotors 7 . 27 and 10 . 30 separate from each other and the second rotor 10 . 30 with a constant field (cogging torque) in a position arrest. Because of the low magnetic and mechanical inertia of the first engine 5 . 25 you can realize a drive with high dynamics.

If you have the coil windings 9 . 29 of the second engine 8th . 28 against the coil windings 6 . 26 of the first engine 5 . 25 rotated by half a phase against each other, you can level the torque curve at zero speed. The first engine 5 . 25 then serves at very low speeds only to compensate for the angular dependence of the torque of the second motor 8th . 28 , This can compensate for one of the major disadvantages of an electric motor, namely the poor controllability of its torque at low speeds.

In a special embodiment is the adhesion between the two rotors by a friction lining on the facing each other Front sides of the rotors produced.

The pressing force can be achieved by an elastic element, for example the compression spring 33 on the opposite side of the second rotor 30 are generated, which are the two rotors 27 . 30 pressed against each other, wherein the spring force in the axial support of the bearing rod 24 is caught.

The traction can be lifted by a "freewheel", the two rotors 27 . 30 separates as soon as a resulting torque occurs between the two rotors.

A resulting torque between the rotors 27 . 30 You can generate by winding the coil 29 of the second engine 28 subjected to a constant current and in the coil windings 26 of the first engine 25 generates a rotating field that rotates at the desired speed.

But the traction can also by the centrifugal clutch 12 be lifted above a certain speed.

By the drive device according to the invention with the help a brushless DC motor became the problem the adaptation of the dynamics of the engine to different load cases solved.

Alternative to the continuous motor shaft 4 . 24 can the two rotors 7 . 10 ; 27 . 30 each also be arranged on separate shafts. It is crucial that the force field of a rotor 7 . 27 via the coupling devices 12 . 32 on the second rotor 10 . 30 is transmitted. However, this embodiment is needed for each rotor 7 . 10 ; 27 . 30 two bearings. The continuous motor shaft 4 . 24 for both rotors 7 . 10 ; 27 . 30 on the other hand saves a depository.

at the motors may be an internal rotor motor (as shown) or act around an outer rotor motor.

The Both coil windings can have a PWM signal be controlled either jointly or separately.

The second embodiment shows as a mechanical coupling the two rotors via a freewheel and a pressure element in the form of a spiral or plate spring. The power flow of the two Rotors is made by the freewheel, which is the two engines separates as soon as between the two rotors a resulting torque occurs. With the spring, a pressing force on the Rotor produced at low speed. The two rotors are against each other pressed. The spring is supported in the axial support the common motor shaft.

The First embodiment shows the concept with a centrifugal clutch instead of a freewheel and spring

By a drive device with an inventive Combination of several motors of different characteristics can all possible requirements are solved. at two motors, the one a low moment of inertia have at a high speed. The second engine high torque generate at low speeds. By at low speeds acting coupling device is the high torque of the second Motors transferred to the first engine. The first engine then serves at high speeds due to its lower moment of inertia for the sole drive. It would still be possible a third engine that cuts the middle areas in both torque as well as in the speed covers.

1

casing

2

first camp

3

second camp

4

motor shaft

5

first Engine high RPM

6

first coil winding

7

first rotor

8th

second Motor low RPM

9

second coil winding

10

second rotor

11

rotor bearing

12

centrifugal clutch

21

casing

22

first camp

23

second camp

24

motor shaft

25

first Engine high RPM

26

first coil winding

27

first rotor

28

second Motor low RPM

29

second coil winding

30

second rotor

31

rotor bearing

32

freewheel

33

compression spring

34

spring isolation

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 10147073 A1 [0007, 0007]
• - DE 29824616 U1 [0008]
• - DE 19704504 A1 [0009]

Claims (13)

Drive device with a housing ( 1 . 21 ), one in the housing ( 1 . 21 ) arranged first motor ( 5 . 25 ) with a low moment of inertia, one in the housing ( 1 . 21 ) arranged second motor ( 8th . 28 ) with high torque, a coupling device ( 12 . 32 ), by means of which the rotors ( 7 . 10 ; 27 . 30 ) of both engines ( 5 . 8th ; 25 . 28 ) are positively connected with each other. Drive device according to claim 1, characterized in that the coupling device ( 12 . 32 ) at low speeds the rotors ( 7 . 10 ; 27 . 30 ) of both engines ( 5 . 8th ; 25 . 28 ) connects positively with each other. Drive device according to claim 1 or 2, characterized in that both motors ( 5 . 8th ; 25 . 28 ) around a common motor shaft ( 4 . 24 ), one of the motors ( 5 . 8th ; 25 . 28 ) directly with the motor shaft ( 4 . 24 ) and the other motor ( 8th . 28 ) on the common motor shaft ( 4 . 24 ) is rotatably mounted. Drive device according to one of claims 1 to 3, characterized in that the coupling device ( 12 . 32 ) of the two motors ( 25 . 28 ) a freewheel ( 32 ) and a pressing element ( 33 . 34 ) having. Drive device according to claim 4, characterized in that the pressure element ( 33 . 34 ) is a coil spring or a plate spring. Drive device according to one of claims 1 to 3, characterized in that the coupling device ( 12 . 32 ) of the two motors ( 5 . 8th ) a centrifugal clutch ( 12 ) having. Drive device according to one of claims 1 to 6, characterized in that the stators ( 6 . 9 ; 16 . 19 ) of the two motors ( 5 . 8th ; 25 . 28 ) are stacked in the axial direction such that they have a common axis of symmetry, that the rotor ( 7 . 27 ) of the first engine ( 5 . 25 ) rigidly with the bearing rod ( 4 . 24 ), that the rotor ( 10 . 30 ) of the second motor ( 8th . 28 ) around the bearing rod ( 4 . 24 ) is rotatably arranged and that in dependence on the required speed and the applied load via a coupling device ( 12 . 32 ) the two rotors ( 7 . 10 ; 27 . 30 ) are positively connected to each other. Drive device according to one of claims 1 to 7, characterized in that the first motor ( 5 . 25 ) a first rotor ( 7 . 27 ) with a low moment of inertia and a first coil winding ( 6 . 26 ) having low inductance. Drive device according to claim 8, characterized in that the first rotor ( 7 . 27 ) has a small rotor diameter with a low moment of inertia and consists of a magnetic material with a small saturation flux density, and that the first coil winding ( 6 . 26 ) has a small number of turns with low inductance. Drive device according to one of claims 1 to 9, characterized in that the second motor ( 8th . 28 ) a rotor ( 10 . 30 ) with a high torque and a coil winding ( 9 . 29 ) having high inductance. Drive device according to claim 10, characterized in that the second rotor ( 10 . 30 ) has a large rotor diameter with high torque and consists of a magnetic material with high saturation flux density and the coil winding ( 9 . 29 ) has a high number of turns with high inductance. Drive device according to one of claims 1 to 11, characterized in that the two motors ( 5 . 8th ; 25 . 28 ) are brushless, with permanent magnets excited DC motors. Drive device according to one of claims 1 to 12, characterized in that sensors are provided which detect load and speed fluctuations and by means of a control circuit to the rotating field of the first coil winding ( 6 . 26 ) act to compensate for load and speed fluctuations.