ES2341539T3 - POSITION DETECTOR. - Google Patents

Abstract

The system includes an excitation magnet (EM), only a single ferromagnetic component (FE) with a coil (SP or SP1) and an additional sensor component (SE) determining information concerning polarity and position of the excitation magnet (EM). At the instant (Ts) of triggering the ferromagnetic component, complete information is made available to determine the direction of motion of the excitation magnet.

Description

Position detector.

The invention relates to a detector of position for recording translation movements and / or of rotation using a ferromagnetic element.

Such ferromagnetic elements are known. as in US 4,364,013 as the so-called detectors of impulse wire movements or in standard DE 41 07 847 C1 or in DE 28 17 169 C2 as Wiegand sensors, in which p. eg a Ferromagnetic material is wrapped by a sensor coil. The magnetic sectors first oriented irregularly in the material ferromagnetic - referred to as magnetic domains or as Weiss domains - they are targeted in a single domain under the influence of external forces. When applying a magnetic field external address and intensity, this domain is "changes" "suddenly", which causes a boost from voltage in the sensor coil that can be detected as a signal of exit.

In a variant known as angle sensor turn, see p. eg, EP 0724712B1, pass on such impulse wires distributed magnets distributed around the perimeter and repositioners, so that the impulse wires are traversed successively by magnetic fields of inverse polarity. Because the magnetic inversion of all its magnetic sectors in its coil sensor, each pulse wire generates a voltage pulse of one defined length, amplitude and polarity. These voltage impulses They are evaluated in an electronic counter. Through the magnets of repositioning the magnetic sectors of the impulse wires to the starting state through the field of repositioning of opposite polarity, so that the corresponding Pulse wire is ready for a new pulse activation. This procedure is called asymmetric operation. In symmetric operation is generated additionally in each process of replenishment an evaluable impulse.

As in the standard mentioned at the beginning EP 0 724 712 B1, with at least two sensors of this type distributed by the perimeter in the direction of movement, can be extracted not only each complete turn of a rotating shaft but also its direction of turn taking into account the characteristics position differences between the placement and replacement process with a clear assignment of the voltage pulses generated to the corresponding position angle of the turning shaft.

Due to the at least two sensors distributed around the perimeter, we must have a considerable assembly cost, as pulse wire sensors are not as small as one wishes, so, p. eg, you cannot build speed counters with a small diameter. In addition, these sensors are relatively expensive.

It is also known that in a position detector of this type can be determined with the help of a single sensor the rotation and the direction of rotation of an axis, inclining the constituted sensor as Wiegand thread for impulse generation dependent on the direction of movement towards the direction of movement of a section with magnetic polarity opposite the Wiegand wire; see the aforementioned DE 28 17 169 C2. Disadvantageous in a provision of this type is that, as a consequence of polarization predetermined although a detection of the direction of rotation, however this is limited to the direction of predetermined turn by polarization, that is, only to a single direction of rotation

For the registration of both directions of rotation of at least two sensors of this type are necessary with the corresponding evaluation connections. Regardless of this, such a provision suffers under certain circumstances of an energy efficiency very reduced since the angle between the direction of movement and Sensor orientation plays a determining role. You work without outside power supply is therefore difficult with such an arrangement.

Task of the invention is to obtain in this regard a solution.

Starting from the fact that in the materials ferromagnetic the interaction of the magnetic moments of atoms neighbors with different magnetization direction is very strong, what which leads to the orientation of moments in small domains, the so-called Weiss domains, which are separated from each other by some transition layers, referred to as Bloch walls, is now possible to permanently form a single domain of unitary direction of magnetization p. ex. by stretching mechanic of a ferromagnetic thread. If you place a domain of this type in an external magnetic field of certain size and address, then this domain does not fold in its entirety but that your elemental magnets are deployed from a certain initial position - preferably, from the end of a thread - to dominoes mode, in the direction of the magnetic field external. This leads to a finite velocity fustigation wave. in the ferro magnetic element but that is large enough versus the speed of the magnet to excite, so that you can talk about a "sudden fustigation" of these domains.

Taking advantage of physical relationships above described, the task mentioned at the beginning for a detector position of the type described here that has at least one magnet exciter, has been solved from within the meaning of the invention with a single ferromagnetic element with at least one coil of induction and with at least one additional sensor element to find out information on the polarity and position of the exciter magnet, being available at the time of activation of a ferromagnetic element as complete information to determine the direction of movement of the exciter magnet. Wall effect of Bloch that passes over the ferromagnetic element is take advantage of a particularly simple variant of the invention of such that the finding of the position of the exciter magnet is produced by determining the activation direction of the magnetic inversion of the ferromagnetic element initiable from both front sides.

However, you should not confuse here the direction of activation of the magnetic inversion with the direction of the same magnetic inversion, which is described as from which pole magnetic up to which magnetic pole the walls are "whipped" Weiss The direction of the magnetic inversion leads in the case present to the polarity of the activating pole of the exciter magnet.

The kinetic energy of elementary magnets fustigants in the form of a continuous wave in the direction of the domain outside is large enough not only to extract from the coil assigned to the ferromagnetic element electrical energy for a signal pulse but also for a counter electronics and a Hall probe

If the current position and polarity of the EM exciter magnet and apply these in relation to your last stored position and polarity, then information is held complete to find out the direction of movement of the magnet EM exciter and rotating shaft firmly attached to it. For one better understanding of the invention is explained below the same based on the example of a revolution counter.

In the general case, which is characterized by a exciter magnet and ½ turn activation, described completely the lap counter system by four basic states of the exciter magnet in combination with its latest stored data, namely:

Z1.) North pole to the right of the line reference

Z2.) North pole to the left of the line reference

Z3.) South pole to the right of the line reference

Z4.) South pole to the left of the line reference.

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In a use according to the invention of only one impulse wire and an induction coil, these four situations they lead to two groups of states combined according to the use of The activation direction of the magnetic inversion:

1.) Group: both activation directions of the magnetic inversion are defined; see fig. 1 2 and 3.

to.)

north pole to the right or south pole to the left of the reference line L (Z1 or Z4)

b.)

north pole to the left or south pole to the right of the reference line L (Z2 or Z3).

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Here you can determine the position of the magnet EM exciter by measuring the activation direction of magnetic inversion by means of the additional sensor element, e.g. eg, a second induction coil or a Hall probe. With a second coil SP2 on the ferromagnetic element FE this is produced directly and with a Hall HS probe is produced indirectly. If a Hall HS probe is used, it does not play a paper here the polarity known by that of the EM exciter magnet but only the fact of whether he is excited or not. The polarity of the magnet EM exciter can then be determined by always measuring the direction of magnetic inversion by induction coil SP1 or SP of the ferromagnetic element FE of the polarity of the voltage impulses

2.) Group: only a direction of activation of the magnetic inversion is defined; see fig. Four.

to.)

north pole to the right or north pole to the left of the reference line L (Z1 or Z2)

b.)

south pole to the right or south pole to the left of the reference line L (Z3 or Z4).

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In this case, the position of the EM exciter magnet it is always deduced directly from the Hall probe seeing if it excited or not. The polarity of the EM exciter magnet can be determined independently by means of the induction coil SP measuring the Magnetic inversion direction. 3.) group: the address of the magnetic inversion is not defined; see fig. 5.

to.)

pole north to the right of the reference line L above or south pole to the right of the reference line L below (Z1 or Z2)

b.)

pole north to the right of the reference line L below or south pole to the right of the reference line L above (Z4 or Z3).

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Depending on the layout of the Hall HS probe on the right (as indicated in fig. 5) or on the left, They evaluate the corresponding polarities. The polarity of the magnet EM exciter is deduced here directly by the Hall HS probe. The determination of the position of the EM exciter magnet (north pole or south pole up or down) is now performed indirectly by means of the measurement of the direction of magnetic inversion.

All solutions with mathematically equivalent and technologically of the same value.

Through the measures of the invention above indicated you can build a position detector with a very simple mechanical structure that works perfectly also to near zero speeds and in case of supply drop regulate the current with a single ferromagnetic element in both directions of movement of the exciter magnet. Here it is due highlight that at the moment Ts of the activation of the element Ferromagnetic FE are available full information for finding out the polarity and the direction of movement, that is, together with the stored information all the necessary signals at the output terminals of the coils of Induction affected and / or the Hall probe. This fact conditions necessarily as a claim that the ferromagnetic element FE, Hall HS probe and EM exciter magnet or magnets excitators, they have to find each other in a constellation very specific space, p. eg, in one place.

Optimally simplified configuration of the position detector also allows to extract from the signals of output of the SP sensor coil or SP1 sensor coils; SP2 at same time the energy for evaluation electronics that includes at least one counting device, a non-volatile memory and a condenser.

Other features of the invention are derived of the derived claims.

The invention is described below on the basis to five examples of execution more or less exposed schematically

It shows:

Fig. 1 the schematic structure of a detector position according to the invention with a ferromagnetic element, two assigned inductor coils and two pieces of flow conductance Ferromagnetic

Fig. 2 the schematic structure of a detector position according to a second embodiment of the invention with a ferromagnetic element with an inductor coil, a probe Hall and two pieces of ferromagnetic flow conductance.

Fig. 3 the schematic structure of a detector position according to a third embodiment of the invention with a ferromagnetic element, with an inductor coil, a Hall probe and two pieces of ferromagnetic flow conductance.

Fig. 4 the schematic structure of a detector position according to a fourth exemplary embodiment of the invention with a ferromagnetic element, with an inductor coil and a probe Hall.

Fig. 5 the schematic structure of a detector position according to a fifth embodiment of the invention with a ferromagnetic element, with an inductor coil, a Hall probe and two pieces of ferromagnetic flow conductance arranged in 180º.

Fig. 6 a wiring diagram of a electronic evaluation appropriate for the forms of execution according to fig. 1 to 5

Fig. 7 an arrangement of a detector position according to fig. 5, in which the axis of rotation of the magnet exciter is turned 90 °, that is, arranged according to fig. 4 Y

Fig. 8 an arrangement of a detector position according to fig. 7, in which the axis of rotation of the magnet exciter is turned 90 ° with respect to the arrangement according to fig. 5, although it shows two exciter magnets in order to achieve A simpler exhibition.

In the embodiment shown in fig. one of a position detector, the body that moves is an axis 10 that you can turn in the direction of arrow R1 and R2, that is, in the clockwise or counterclockwise. To counting the turns of axis 10 has been assigned to it an exciter magnet EM pointing towards the north pole N and another towards the south pole S. Through the FL1 ferromagnetic flow conductance parts and FL2, whose ends 14 and 15 rest on circular arcs described by the exciter magnet EM and whose ends 16 (position a the left of the reference line L in FE) and 17 (position at right of the reference line L in FE) are directed to the front sides of a ferromagnetic element FE, the element Ferromagnetic FE can be influenced by the magnetic field generated by the EM exciter magnet.

The ferromagnetic element FE oriented parallel to the direction of movement of the exciter magnet, it is surrounded by two SP1 and SP2 sensor coils, on whose terminals of output 22 and 23 the voltage pulses of the corresponding polarity when passing the EM exciter magnet as consequence of the magnetic inversion of the ferromagnetic element FAITH. As an additional sensor element to find out the address of activation of the magnetic inversion serves here the second coil of induction SP2. Temporary displacement of maximum voltage the activation address of the magnetic inversion and, consequently, the position of the magnet EM exciter. Strictly seen, you only need to evaluate the coil with logic "1" that first reaches its maximum of tension. The other coil has not yet reached its maximum, so it is evaluated with logic "0". How Ferromagnetic element serves a thread of impulses.

In the embodiment according to fig. 2, the corresponding elements carry successively the same figures of reference that in the embodiment according to fig. one.

However, different from fig. 1 is that at ferromagnetic element FE only one sensor coil has been assigned SP. In order to determine the position of the exciter magnet at passage of the ferromagnetic element, it is planned here as an element additional sensor a Hall HS probe whose output 24 can be Receive a signal well or not. The polarity is determined here, as in fig. 1, by the SP coil of the ferromagnetic element FE. The polarity determined by Hall HS probe does not matter for the evaluation but can be used as redundant information to a function supervision.

The information that is available in the TS moment to find out the polarity and direction of movement of the exciter magnet consists, therefore, of the data in non-volatile memory with the signals at the output terminals of the induction coils or with the signals at the output terminals of the induction coil and the output terminals of the Hall probe.

The position detector execution method according to fig. 3 shows the elements corresponding to the examples described above, however to increase the resolution 10 exciter magnets EM1 to EM4 have been assigned to axis 10 arranged at right angles to each other, also with polarity alternating Thus, when turning axis 10, they will confront alternately to the front sides of the ferromagnetic element FE a north pole or a south pole through the conductance pieces of flow FL1 and FL2. The necessary Hall probe for the determination of the position of the exciter magnet is here assigned to the ends opposite of the exciter magnets EM1 to EM4.

The position detector execution method according to fig. 4 shows the elements corresponding to the shapes of execution described above, but there are no pieces of flow conductance. In this variant, the use of fact that the ferromagnetic element FE has already been activated before that the EM exciter magnet is in a line with the ferromagnetic element FE. The visible area of the Hall HS probe necessary for the determination of the position of the EM exciter magnet has been adjusted so that it reaches approximately up to reference line L.

The position detector execution method according to fig. 5 also shows the elements corresponding to the forms of execution described above, but here the extremes of the flow conductance pieces FL1 and FL2 found in front of the exciter magnets are arranged in 180º. Probe Hall, necessary to find out the polarity of the exciter magnet as additional sensor element, is arranged here at right angles with respect to the reference line L by the axis 10 pivot point such that you still see the corresponding poles of the exciter magnet MS when the ferromagnetic element is activated. This takes place always at a certain angle? before entering the pieces of flow conductance. The position of the exciter magnet EM is determined by the coil of the ferromagnetic element FE measuring the direction of the magnetic inversion. The previous one variant according to fig. 5 has enough with the EM exciter magnet smallest possible, especially when the conductance pieces Flow rates are also used for the concentration of flow in the form of a magnetic lens.

In the exemplary embodiments according to fig. one up to 5 execution forms have been shown in which the magnet EM exciter and the ferromagnetic element FE are in a plane with respect to normal axes of rotation. Of course it is possible and, under certain circumstances, it is even advantageous that the ferromagnetic element FE and the exciter magnet EM are located in different planes - as shown in fig. 7 - or in a flat but parallel to the normal axis of rotation - as depicted in fig. 8.

The position detectors have been assigned, according to fig. 1 to 5 as well as 7 and 8, an electronics of evaluation named in its entirety with reference figure 30, depicted in fig. 6 as a block diagram, whose terminals are input 32 and 33 are connected to the SP1 and SP2 sensor coils or with SP and with the Hall HS probe. In the input terminals you will find postconnected a detection logic 34 and 35 respectively. In the input 32 an additional capacitor C is connected for the supply of current through a rectifier current D. The signals from the detection logic 34 and 35 are evaluated in a counter 38, to which a nonvolatile memory 36. Including previous history contained in the data stored and the information provided by the Logic detection 34 and 35 on the current position and polarity of the exciter magnet, a new counter status is obtained which is then transmits to nonvolatile memory, which represents in general a FRAM.

The power supply for electronics of evaluation usually comes from the signals of the coils of induction SP, SP1 and SP2. If only one induction coil is used SP, the power supply of the Hall probe is produced from it mode through this coil.

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Line connection 41 is part of the supply voltage of the evaluation electronics described above. Through data can be collected from sockets 39 and an interface 40. A line 42 serves - if planned - for the supply of energy from the outside, especially if in addition to the FRAM employs an EEPROM. An EEPROM of this type places the electronics of evaluation in most cases in the work situation even with the highest temperatures then, p. eg they would also be lost in a FRAM after a short time Important configuration data.

All execution examples described above they have in common that the rotation and / or direction of rotation of the axis 10 is can register accurately with the help of a single item ferromagnetic, p. eg, a thread of impulses that also puts sufficient energy provision for both the supply of a evaluation electronics as for a Hall probe, as an element additional sensor In the arrangement of the impulse wire according to the invention in the simplest variant, where both ends of the impulse wire are of the same value from a perspective of the measurement technique, both position information and also on the polarity of the activating exciter magnet are contained in the voltage pulses generated.

Essential is also here that they are available information on the direction of activation of the investment magnetic of the ferromagnetic element, of the magnet activating pole EM exciter and its last polarity and position stored in the referring to the axis that rotates at the moment Ts of the activation of the ferromagnetic element, that is, at the same time within the framework of the reaction times of the elements used.

The capacitor C in the evaluation electronics It is planned for storage of supply energy obtained from the signal impulse, at least until the evaluation of the signal and the counter value storage process has concluded in nonvolatile memory.

As ferromagnetic elements, instead of impulse wires or Wiegand threads, others can also be used elements if the conditions for "fustigation are met Sudden "of Weiss domains.

To avoid misunderstandings, it should be noted that the ferromagnetic element FE is characterized by only having one magnetic input and magnetic output, neglecting the fields of dispersion. Consequently although it is possible that between the entrance and the output can be interrupted in parallel and / or in series, however that is why the inventive idea of a single element is not abandoned.

For the determination of polarity or position of the exciter magnet, can be used instead of Hall sensors also other sensors like, e.g. eg, photoresist cells sent by magnetic field. In addition, it is possible to prepare the magnet exciter so that its position and / or polarity can be determine instead of by the Hall probe with the help of a measurement capacitive Regardless, the use of the position detector described above in combination with a sensor precision angle of rotation in the form of a so-called Multiturns, as described and represented p. eg, in EP 0 658 745. In this case, the reference line L corresponds to the zero point of the sensor of the precision rotation angle used.

If used p. For example, Wiegand wires, when synchronizing with a precision angle of rotation sensor it is necessary to obtain exact information about the magnetization state of the FE ferromagnetic element. For this it is appropriate, p. eg, the arrangement according to fig. 1 with two coils. With the help of an externally supplied current in a coil, p. For example, coil SP1, a voltage pulse can be activated depending on the magnetization of the ferromagnetic element FE, in the second coil, p. e.g., in coil SP2. The same procedure is also possible with two coils arranged one above the other. Moreover, it is also possible to achieve activation with a short current pulse or a slow-rising current ramp to get out of the pass only with a single
SP coil.

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List of reference drawings

10

axis

14

End

fifteen

End

16

End

17

End

22

Output terminal

2. 3

Output terminal

24

Output terminal

30

Evaluation electronics

32

Input terminal

33

Input terminal

3. 4

Detection logic

35

Detection logic

36

Non volatile memory

38

Accountant

39

You take

40

Interface

41

Line connection

42

Line

α

Activation angle

C

Condenser

D

Current rectifier

EM

Exciter magnet

EM1

Exciter magnet

EM2

Exciter magnet

EM3

Exciter magnet

EM4

Exciter magnet

FAITH

Ferromagnetic element

FL1

Flow conductance piece

FL2

Flow conductance piece

HS

Hall probe

L

Reference line

N

North Pole

R1

Arrow

R2

Arrow

S

South Pole

SP

Sensor coil

SP1

Bonina sensor

SP2

Sensor coil

BE

Additional sensor element

Ts

Moment of activation of the ferromagnetic element FAITH

Z1

Basic state of the exciter magnet

Z2

Basic state of the exciter magnet

Z3

Basic state of the exciter magnet

Z4

Basic state of the exciter magnet.

Claims (13)

1. Position detector for recording translation and / or rotation movements with at least one magnet exciter (EM), only a ferromagnetic element (FE) with at least an induction coil (SP or SP1) and with at least one sensor element additional (SE) to obtain information on polarity and the position of the exciter magnet (EM), being available at the moment (Ts) of the activation of a ferromagnetic element (FE) as complete information for the determination of the direction of movement of the exciter magnet (EM). 2. Position detector according to claim 1, characterized in that the ferromagnetic element (FE) is a pulse wire. 3. Position detector according to claims 1 and 2, characterized in that the induction coil (SP or SP1) is used to measure the direction of the magnetic inversion and in relation to the additional sensor element (SE) to find out the direction of the activation of the magnetic inversion of the ferromagnetic element (FE). 4. Position detector according to claims 1 to 3, characterized in that the additional sensor element (SE) is a second induction coil (SP2) on the ferromagnetic element (FE) and serves to determine the direction of activation of the magnetic inversion of the ferromagnetic element (FE). 5. Position detector according to claims 1 to 3, characterized in that the additional sensor element (SE) is a Hall probe (HS) for measuring the polarity or finding the position of the exciter magnet (EM). 6. Position detector according to claims 1 to 5, characterized in that the complete information available at the moment (Ts) for the determination of the polarity and direction of movement of the exciter magnet (EM) consists of the data in the memory non-volatile with the signals at the output terminals (22, 23) of the induction coils or (SP1, SP2) or with the signals at the output terminals (22) of the induction coil (SP) and the terminals of output (24) of the Hall probe (HS). 7. Position detector according to claims 1 to 6, characterized in that the axis of the ferromagnetic element (FE) is oriented parallel to the direction of movement of the exciter magnet (EM). 8. Position detector according to claims 1 to 6, characterized in that the axis of the ferromagnetic element (FE) is oriented vertically to the direction of movement of the exciter magnet (EM). 9. Position detector according to claims 1 to 8, characterized in that at least one piece of flow conductance (FL1 and / or FL2) is assigned to the ferromagnetic element (FE) for flow guidance and / or flow concentration. 10. Position detector according to claims 1 to 9, characterized in that from the signals of the induction coils (SP, SP1, SP2) for the detection of the position and / or polarity, the power supply for evaluation electronics 11. Position detector according to claims 1 to 10, characterized in that the evaluation electronics (3 = includes at least one counter device (38), a non-volatile memory (36) and a capacitor (C). 12. Position detector according to claims 1 to 11, characterized in that the non-volatile memory (36) is a FRAM and / or an EEPROM. 13. Position detector according to one or more of the preceding claims, characterized in that one of the coils (SP / SP1) is driven by an external current pulse that serves either for activation or for additional prestressing of the ferromagnetic element (FE) .