DE102006030737A1 - Electric motor, has permanent magnets which are provided in pivoted part particularly in part connected with rotor shaft particularly in fan, for producing magnetic field influencing sensor signals - Google Patents

Abstract

The motor has permanent magnets (8) which are provided in a pivoted part particularly in the part connected with the rotor shaft particularly in a fan, for producing magnetic field influencing the sensor signals. The permanent magnets are so arranged that the produced field in the angular position of the pivoted part has a non-diminishing component along the sensor wire and a non-diminishing other component in circumferential direction in sensitive area of the sensor. The shield is composed of two layers of magnetically conductive material, in particular ferrite material or steel sheet.

Description

The The invention relates to an electric motor.

From the DE 10 2005 023 010 A1 and the DE 10 2004 013 022 B3 as well as the DE 10 2005 006 419 A1 are impulse wire sensors, known as Wiegand wires.

Of the The invention is therefore based on the object, an angle detection or at least one revolution counter further education.

According to the invention Task in the electric motor according to the features specified in claim 1 solved.

Important features of the electric motor are that it is provided with electromagnetically actuated brake,
wherein a sensor is provided for detecting the angular position of the rotor or at least for detecting the revolutions,
wherein the sensor comprises at least one pulse-wire sensor and / or Wiegand sensor,
wherein permanent magnets are provided on a rotatably mounted part, in particular on a part connected to the rotor shaft, in particular on the fan, in particular for generating magnetic fields influencing the sensor signals,
wherein the permanent magnets are arranged such that
at least in an angular position of the rotatably mounted part
the generated field in the sensitive region of the sensor has a non-vanishing first component along the sensor wire and a non-vanishing second component in the circumferential direction.

From The advantage here is that magnet arrangements can be provided, in which the field is essentially passed to the sensor and only small ones Parts of the field are not provided in the sensor area. Thus, can also a magnetically effective shielding the field lines only insignificantly influence. Thus changed Sensitivity is not significantly affected by the shielding. However, the shielding is independent of magnetic fields Origin very effective.

at an advantageous embodiment is an essential part of Field lines through the sensitive area of the sensor, in particular these have only a short air gap. It is advantageous that a good signal-to-noise ratio is achievable.

at An advantageous embodiment is the magnetization of the permanent magnets directed towards or away from the sensor. Is an advantage doing that the air gap is short and therefore sensitive Area of the sensor, a high part of the field can be effective.

at An advantageous embodiment is the magnetization of the permanent magnets provided in or against one direction, which is an approximately equal component in the axial and circumferential directions. The advantage here is that the field by permanent magnets on a very compact space area such It is feasible that it is very sensitive to the shortest path Area of the sensor and from there to another permanent magnet leads.

at In an advantageous embodiment, the generated field is sensitive Area of the sensor substantially homogeneous. The advantage here is that the triggering the sensor at one as accurate as possible known angular position executable is.

at an advantageous embodiment, the amount of the first component at least 10% or preferably at least 40% of the second component is, In particular, both components are preferably about the same size. Is an advantage in that a lower error rate is achievable.

at an advantageous embodiment, the field lines, which penetrate the sensitive area of the sensor, in a projection on a plane parallel to the rotor axis, passing through the sensitive Range of the sensor is, a first curvature. In particular, show the field lines, which penetrate the sensitive area of the sensor, in a projection on a plane whose normal is the rotor axis and that goes through the sensitive area of the sensor, one second curvature on. The advantage here is that the overall spatial course of the field lines can be conducted through the sensitive area of the sensor, that the air gap is very short.

at an advantageous embodiment, first and second curvature have the same Signs and / or differ in the amount of at most 50%. The advantage here is that a particularly short path can be achieved is, although a big one Value of the towards the sensor wire and thus for the detection effective portion of the magnetic field is providable.

In an advantageous embodiment, the permanent magnets have a square or rectangular cross-section and provided the magnetization of the permanent magnets along a diagonal of an imaginary cube, which is located in the interior of the permanent magnet and whose outer edge surfaces outer edge surface areas of Dau are magnets. The advantage here is that the direction of the magnetic field can be directed to the sensor.

at an advantageous embodiment, the permanent magnets or at least two permanent magnets parallel to each other and in an angular position also arranged parallel to the sensor wire. It is advantageous that one possible homogeneous field in the sensitive area of the sensor can be reached.

at an advantageous embodiment is an axially on the of the Permanent magnet side facing away from the sensor provided a shield, in particular for shielding magnetic field, which is arranged from an axially adjacent Electromagnetically actuated Brake can be generated. The advantage here is that less influence the sensor triggering magnetic fields through the brake field takes place, so one low error rate is achievable.

at An advantageous embodiment is remote from the sensor on the Side of the permanent magnets provided a part of magnetically conductive material. The advantage here is that the reflux between the permanent magnets is passable.

at An advantageous embodiment is between the sensor and the brake at least one shield provided, in particular the shield at least an axially provided between the sensor and brake rear wall comprises. The advantage here is that thus an effective shielding providable is against otherwise axially occurring interference fields. It is also advantageous that originating from the brake coil and / or the coil core of the brake coil interference can be reduced and thus a reliable detection of the angular position the permanent magnet rotating past the sensor is executable.

at In an advantageous embodiment, the shield surrounds the sensor partially, in particular half-pocket-shaped. It is advantageous that the shield is improved executable and also entering the side Fields are better shielded.

at According to an advantageous embodiment, the shield comprises at least a layer of magnetically conductive Material, in particular ferrite material or steel sheet or the like, includes. The advantage here is that inexpensive material usable is.

at According to an advantageous embodiment, the shield consists of at least two layers of magnetically conductive Material, in particular ferrite material or steel sheet or the like, wherein between the layers a layer of non-magnetic material, as air or plastic, is provided. It is advantageous that the shield improves and effectively more effectively providable is.

at an advantageous embodiment, the shield has an L-shaped cross-section, if the cutting plane comprises the axis of the engine, and / or the Shielding at least a U-shaped running Bead which protrudes in the axial direction, wherein the sensor is provided inside the bead. The advantage here is that the shield is inexpensive to produce in a simple manner.

at In an advantageous embodiment, permanent magnets are rotatable on one mounted part, in particular at one connected to the rotor shaft Part, especially on the fan, provided, in particular for generating the sensor signals influencing Magnetic field. The advantage here is that the revolution counter or Angle sensor integrated in the engine is executable. If available Fan even this is co-usable.

Further Advantages emerge from the subclaims.

The Invention will now be explained in more detail with reference to figures:

In the 1 is an inventive electric motor drawn in symbolic sectional view.

In this case, the motor comprises a motor shaft which is connected to the rotor, which is inside the stator in the motor housing 1 is arranged. Axial then an electromagnetically actuated brake is arranged, the brake coil 2 symbolically indicated. When energizing the brake coil 2 An armature disc is attracted against a bias generated by spring elements and thus one with the motor shaft 7 connected brake pad axially pressed against the armature disc and / or a braking surface. When the brake is energized, various kinds of electromagnetic interference fields are created. Also by the use of electronic power semiconductors to control the current through the brake coil such fields are generated.

In the axial direction, a fan connects, the permanent magnets 8th which, with sensors 5 interact. Here are the sensors 5 designed as Wiegand sensors or pulse wire sensors. Thus, the angular position of the motor shaft 7 detectable. The resolution depends on the number of sensors 5 coarse on the circumference or even designed only for counting the revolutions. A fine resolution encoder can be connected and additionally combined.

The fan housing 3 surrounds at least the sensors and the fan with its fan blades 6 , The sensors generate when passing the permanent magnets 8th a sensor signal which can be influenced by the distance to the magnets and by the direction of movement of the magnets. In particular, the jumps in the state of the sensors are also dependent on the magnitude of the magnetic field strength. Smallest changes in the field strength can thus cause an increase in the error rate.

To shield the magnetic interference from the brake or brake coil are therefore shielding 4 intended. These are designed such that they shield the fields of the brake originating from the brake coil and the associated coil core. The fields originating from the stator area of the engine are also considerably reduced. One of the sensor associated with a shielding 4 is in 2 shown in plan view. In this case, the shielding means consists of a U-shaped bead 20 which is provided on a rear wall. In 1 is a section visible. The shielding is pronounced L-shaped.

All in all So it's a sensor that's about the same Bag formed of shielding material. Suitable as material a magnetically conductive material, such as ferrite material.

through the shielding means is thus the interference field of the brake verminderbar and the triggering of the Pulse wire sensors or Wiegandsensoren undisturbed.

The magnetically conductive Material passes the leakage flux of the brake past the sensor. The cost of materials for The shielding is low as the sensor is in a thin pocket is provided, so essentially half the space around it is shielded. The volume requirement for the shield is the same low. Thus, the sensor is axially foreseen very close to the brake and the errors are still suppressed.

The for the Sensor needed Installation volume is therefore very low.

In 3a is for a further inventive embodiment, a top view and in 3b the corresponding sectional view shown. In amendment to 1 and 2 So now it's a first shift 30 and a second layer 32 provided, which are each made of magnetically conductive material. The intermediate layer 31 is made of magnetically non-conductive material, such as air, plastic or the like.

The Shielding is thus even more effective.

at another embodiment of the invention are also more than two layers, each with associated intermediate layers intended. The shield is thus still improved, however the shielding is more complex.

In 4 the arrangement of the permanent magnets is shown schematically. Here are the permanent magnets 41 and 42 oriented in parallel, but with a mutual offset and reverse magnetization direction. The sensor is provided stationary, in particular rotatably connected to the brake. The permanent magnets are provided on the fan.

5 shows the advantageous arrangement of the permanent magnets 41 and 42 in a further embodiment, wherein a schematic sectional view. There is the reflux in the part 50 , ie the fan, instead.

The Permanent magnets are magnetized diagonally. Thus, the magnetic flux occurs mainly in the diagonal.

Due to the offset in the radial direction, the in 4 The essential field lines are only briefly shown in the air above the sensor 5 from the permanent magnet 41 to the permanent magnet 42 , Thus, the field lines which have the sensor 5 penetrate, in the projection after 5 a curvature.

In the projection after 4 have the field lines which the sensor 5 penetrate, also a curvature.

Important is also that the field in the area of the sensor is substantially homogeneous is. It has a component in the direction of Wieganddrahtes or Pulse wire on when the permanent magnets rotating past the wire are in such an angular position, so that they are parallel to Wieganddraht are located. In addition, the magnetic field in the area of the sensor also a component in the circumferential direction.

in the Interaction of the diagonal magnetization of the permanent magnets, so the magnetization in one direction, which is an approximately equal component in the axial and circumferential directions, together with the offset of the two permanent magnets arranged parallel to one another a field course that runs through the air, however essentially also by the sensor is concentrated. The axial further away, behind the sensor lying shield influenced Thus, the course of the originating from the permanent magnet field lines little, especially in the area of the sensor.

It is also cause that by the oblique magnetization, the field lines from the permanent magnets essentially emerge in the direction of the sensors. Thus, the substantial part of the magnetic field is directed to the sensors and thus a short airway exists.

The Shielding so to speak does not absorb a significant proportion of field lines path.

6 and the above associated description of the field line course relate to that angular position of the permanent magnets, in which the permanent magnets are aligned parallel to the sensor wire, ie in spatial proximity to the sensor.

1

 motor housing

2

 brake coil an electromagnetically actuated brake

3

 fan housing

4

 screening

5

 Pulse-wire sensor

6

 fan blades

7

 motor shaft

8th

 permanent magnet

20

 U-shaped bead

30

 first layer

31

 interlayer

32

 second layer

41

 permanent magnet

42

 permanent magnet

43

 sensor

44

 fan blades

Claims (21)

Electric motor with windings generating magnetic field, wherein a sensor for detecting the angular position of the rotor or at least for detecting the revolutions is provided, wherein the sensor comprises at least one pulse-wire sensor and / or Wiegand sensor, characterized in that permanent magnets on a rotatably mounted part, in particular on a part connected to the rotor shaft, in particular on the fan, are provided, in particular for generating the magnetic field influencing the sensor signals, wherein the permanent magnets are arranged such that at least in an angular position of the rotatably mounted part, the generated field in the sensitive area of the sensor not one has vanishing first component along the sensor wire and a non-vanishing second component in the circumferential direction. Electric motor according to at least one of the preceding Claims, characterized in that the windings of the stator windings Electric motor and / or windings of an electromagnetically actuated Brake of the electric motor are. Electric motor according to at least one of the preceding Claims, characterized in that a shield at least one axial between sensor and stator winding and / or a winding of the brake provided back wall includes. Electric motor according to at least one of the preceding Claims, characterized in that a substantial part of the field lines passes through the sensitive area of the sensor, especially these only have a short air gap, Electric motor according to at least one of the preceding Claims, characterized in that the magnetization of the permanent magnets directed towards or away from the sensor Electric motor according to at least one of the preceding Claims, characterized in that the magnetization of the permanent magnets is provided in or against one direction, which is an approximately equal component in the axial and circumferential directions, in particular components, which only decide by less than 20 percent in their size. Electric motor according to at least one of the preceding Claims, characterized in that the generated field in the sensitive Area of the sensor is substantially homogeneous. Electric motor according to at least one of the preceding Claims, characterized in that the amount of the first component is at least 10% or preferably at least 40% of the second component, in particular preferably about the same size. Electric motor according to at least one of the preceding claims, characterized in that the field lines, which are the sensitive area of the sensor 5 penetrate, in a projection on a plane parallel to the rotor axis, passing through the sensitive area of the sensor, have a first curvature. Electric motor according to at least one of the preceding claims, characterized in that the field lines, which are the sensitive area of the sensor 5 penetrate, in a projection on a plane whose normal is the rotor axis and passes through the sensitive area of the sensor, have a second curvature. Electric motor according to at least one of the preceding Claims, characterized in that first and second curvature have the same sign and / or not more than 50% in amount differ. Electric motor according to at least one of the preceding Claims, characterized in that the permanent magnets have a square or rectangular Cross section and the magnetization of the permanent magnets along a diagonal is provided Electric motor according to at least one of the preceding Claims, characterized in that the permanent magnets or at least two in each case parallel to each other and in an angular position also parallel to Sensor wire are arranged. Electric motor according to at least one of the preceding Claims, characterized in that an axially facing away from the permanent magnet on the Side of the sensor, a shield is provided, in particular for shielding magnetic field, which is arranged from an axially adjacent Electromagnetically actuated Brake can be generated Electric motor according to at least one of the preceding Claims, characterized in that on the side facing away from the sensor the permanent magnets provided a part of magnetically conductive material is, in particular for passing the reflux between the permanent magnets. Electric motor according to at least one of the preceding Claims, characterized in that between the sensor and at least one winding at least one shield is provided, in particular the shield comprises at least one axially provided between the sensor and brake rear wall. Electric motor according to at least one of the preceding Claims, characterized in that the shield partially the sensor surrounds, in particular half-pocket-shaped. Electric motor according to at least one of the preceding Claims, characterized in that the shield at least one layer magnetic conductive Material, in particular ferrite material or steel sheet or the like, includes. Electric motor according to at least one of the preceding Claims, characterized in that the shield of at least two layers magnetically conductive Material, in particular ferrite material or steel sheet or the like, comprising, between the layers, a layer of non-magnetic Material, such as air or plastic, is provided. Electric motor according to at least one of the preceding Claims, thereby marked that the shield has an L-shaped cross-section has, if the cutting plane includes the axis of the engine, and / or the Shielding at least a U-shaped extending bead which protrudes in the axial direction, wherein the sensor is provided inside the bead. Electric motor according to at least one of the preceding Claims, characterized in that permanent magnets on a rotatably mounted Part, in particular on a part connected to the rotor shaft, especially on the fan, are provided, in particular for the generation of the sensor signals influencing magnetic field.