EP0721067B1 - Fluid-pressure actuator with a magnetic field sensor - Google Patents
Fluid-pressure actuator with a magnetic field sensor Download PDFInfo
- Publication number
- EP0721067B1 EP0721067B1 EP95120518A EP95120518A EP0721067B1 EP 0721067 B1 EP0721067 B1 EP 0721067B1 EP 95120518 A EP95120518 A EP 95120518A EP 95120518 A EP95120518 A EP 95120518A EP 0721067 B1 EP0721067 B1 EP 0721067B1
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- EP
- European Patent Office
- Prior art keywords
- permanent magnet
- cylinder
- piston arrangement
- cylinder piston
- magnetic field
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
- F15B15/28—Means for indicating the position, e.g. end of stroke
- F15B15/2807—Position switches, i.e. means for sensing of discrete positions only, e.g. limit switches
Definitions
- the invention relates to a pressure-operated cylinder-piston arrangement with a permanent magnet on the piston and a magnetic field sensor on the cylinder for querying a path signal, wherein the permanent magnet has a ring shape and is magnetized in the axial direction of the cylinder-piston arrangement, with ring discs made of ferromagnetic material for steering the Magnetic flux.
- a pressure-actuated cylinder-piston arrangement of the above specified genus has become known, for example through DE 35 10 601 A1. It is on the piston rod ring-shaped, axially polarized permanent magnet pushed on. A ring disc made of ferromagnetic material, which also Piston forms, directs the magnetic flux against the cylinder wall. There is a magnetic field sensor on the outside of the cylinder arranged. In this way, the piston releases at one Position by the magnetic field sensor, a signal so that the Piston position is detected.
- the invention is based on the arrangement of the genus specified at the beginning and beats the in the characterizing Features specified in the first claim in front.
- the permanent magnet comes into direct contact Close to the inside wall of the cylinder without touching it.
- the ring disk arranged on one side of the permanent magnet made of ferromagnetic material directs the magnetic Flow along the shortest route against the cylinder. In particular thereby avoiding scattering of the magnetic flux, so that the magnetic flux is confined to a narrow area becomes.
- the outer diameter of the ring disk is made ferromagnetic material is slightly larger than that Outside diameter of the permanent magnet. This will do a suitable one due to the design of the washer or washers Redirection of the flow towards the cylinder wall achieved.
- the axial dimensions of the washer made of ferromagnetic material at most half the size are as the axial dimensions of the permanent magnet. Thereby scatter is largely avoided and the magnetic flux is concentrated.
- the washers can be axially on both sides of the permanent magnet to be ordered. In this case there is a magnetic flux essentially from one ring disc to the other Washer. However, it is better if only one ferromagnetic Washer on one side of the permanent magnet is applied so that only at this point the maximum of Field strength is achieved so that the sensor only this position displays. In special cases, however, it can be recommended be to also use two ferromagnetic washers, whereby then, depending on the arrangement, a somewhat wider area of the Maximum is obtained, or two peaks in the field of ferromagnetic Washers.
- the outside diameter of the permanent magnet slightly smaller than the inside diameter of the cylinder. This ensures that the permanent magnet is not compatible with the Inner wall of the cylinder comes into contact, so that wear on the permanent magnet is prevented. The resulting a somewhat larger distance from the magnetic field sensor does not result Disadvantages because the ferromagnetic ring disk is sufficiently close can reach the inner wall of the cylinder.
- the bushing consists in particular of austenitic steel and is welded into the recess and in a blind hole picks up the sensor. It is clear that in particular If, instead of welding, brazing is also sufficient can be. Through the welded socket and the blind hole the interior of the cylinder is separated from the sensor in the socket. The sensor can be easily replaced. The recess in the cylinder can go inside the cylinder pass. In this case, it is advantageous if the inner end machined the bushing together with the inner surface of the cylinder is. This procedure ensures that despite the used Bush the inner surface of the cylinder completely smooth is, so that no additional stress for the seals arise.
- the invention also proposes that the piston be made of magnetic there is no or little conductive material. With this suggestion should be avoided that the permanent magnet in the piston finds its magnetic return, causing the magnetic field would be reduced in the recess or on the sensor. It was found that low magnetic conductivity for the Material of the piston is at least not disadvantageous.
- the magnetic field sensor is usually fixed to the cylinder.
- the arrangement can also be made such that the magnetic field sensor in a suitable recess along the Cylinder is slidable.
- the job can of the piston in which the magnetic field sensor changes that emits the signal triggered by the permanent magnet of the piston.
- the permanent magnet has relatively small dimensions. So the radial Thickness of the permanent magnet less than a third of the radius of the piston. In particular, it was found that the radial Thickness of the permanent magnet about the sixth part of the radius of the piston to achieve very good results.
- the axial dimensions of the permanent magnet are same as the radial thickness or slightly larger.
- the axial dimensions of the washer or washers Ferromagnetic material are in a preferred embodiment the invention at most half as large as that axial dimensions of the permanent magnet. This ensures one slightly axial expansion of the magnetic field and a corresponding Accuracy of the display by the magnetic field sensor.
- the cylinder-piston arrangement 1 consists essentially of the Cylinder 10, the piston 11 and the piston rod 12.
- the cylinder is closed on one side by the cover 13, which also carries the connecting line 14.
- the piston rod guide 15 is provided is held by the locking ring 16.
- the second hydraulic connection is designated 17.
- a recess 20 is provided in the wall of the cylinder 10, in which the bushing 21 is inserted or welded is.
- This bushing 21 takes the magnetic field sensor in the blind bore 22 2, the connections of which are designated by 23.
- the Magnetic field sensor can be, for example, a reed switch which is housed in a protective tube. It is better however, to provide a magnetic field sensor that in particular has no moving parts and for example on inductive The magnetic field is determined and the corresponding one Emits signal.
- the piston 11 consists essentially of the two parts 18 and 19.
- the parts 18 and 19 are on the threaded pin 30 of the Piston rod 12 held. Due to the two-part training of Piston 11 can be in the annular groove 31 of part 19 of the annular Permanent magnet 3 are inserted.
- the washers 32 and 33 are arranged on both sides of the permanent magnet 3, the washers 32 and 33 are arranged.
- the Permanent magnet 3 is parallel to the central axis 39 of the cylinder-piston arrangement 1 magnetized. For example, the north pole shows towards the piston rod guide 15, the south pole against it towards the cover 13.
- the permanent magnet 3 In the position shown of the piston 11 is the permanent magnet 3 arranged with respect to the recess 20 such that this permanent magnet is located at a point entirely within the Limits of the recess 20 is located, which receives the socket 21. In this way, the magnetic field of the permanent magnet Reach sensor 2 so that a path signal is obtained.
- the Distance "s" indicates approximately how long the switching path is. there it doesn't matter whether the piston is off one or the other in the other direction towards the recess.
- the two washers 32 and 33 can both be made of ferromagnetic Material. Better results or a more precise one However, the signal is received when one of the washers, for example, the washer 32, made of ferromagnetic Material exists while the other washer either is omitted, the width of the annular groove 31 then increasing would decrease, or if this other washer 33 made of aluminum, Brass or a similar material is made. at Such an arrangement will then only open the magnetic field sensor address the position of a ferromagnetic washer 32.
Abstract
Description
Die Erfindung betrifft eine druckmittelbetätigte Zylinder-Kolben-Anordnung mit einem Permanentmagneten am Kolben und einem Magnetfeldsensor am Zylinder zur Abfrage eines Wegsignales, wobei der Permanentmagnet eine Ringform aufweist und in Achsrichtung der Zylinder-Kolben-Anordnung magnetisiert ist, mit Ringscheiben aus ferromagnetischem Material zur Lenkung des Magnetflusses.The invention relates to a pressure-operated cylinder-piston arrangement with a permanent magnet on the piston and a magnetic field sensor on the cylinder for querying a path signal, wherein the permanent magnet has a ring shape and is magnetized in the axial direction of the cylinder-piston arrangement, with ring discs made of ferromagnetic material for steering the Magnetic flux.
Eine druckmittelbetätigte Zylinder-Kolben-Anordnung der vorstehend
angegebenen Gattung ist beispielsweise bekanntgeworden
durch die DE 35 10 601 A1. Dabei ist auf die Kolbenstange ein
ringförmiger, axial polarisierter Permanentmagnet aufgeschoben.
Eine Ringscheibe aus ferromagnetischem Material, der auch den
Kolben bildet, lenkt den magnetischen Fluß gegen die Zylinderwandung.
Auf der Außenseite des Zylinders ist ein Magnetfeldsensor
angeordnet. Auf diese Weise löst der Kolben bei einer
Stellung durch den Magnetfeldsensor ein Signal aus, so daß die
Kolbenposition erfaßt wird.A pressure-actuated cylinder-piston arrangement of the above
specified genus has become known, for example
through
Vorrichtungen der bekannten Art finden vor allem bei Pneumatikzylindern Anwendung. Die bei pneumatischen Einrichtungen vorherrschenden relativ geringen Drücke erlauben für das Zylinderrohr geringe Wandstärken und außerdem auch die Verwendung von Werkstoffen, wie zum Beispiel Aluminium oder auch Messing, die für das Magnetfeld gut durchlässig sind, so daß der Sensor auf das Magnetfeld ansprechen kann.Devices of the known type are found primarily in pneumatic cylinders Application. The prevailing in pneumatic equipment allow relatively low pressures for the cylinder barrel small wall thicknesses and also the use of Materials such as aluminum or brass, the are well permeable to the magnetic field, so that the sensor on can respond to the magnetic field.
Bei dickwandigen Rohren, wie diese bei hydraulischen Anlagen notwendig sind, insbesondere bei dickwandigen Stahlrohren, die in der Regel magnetisch leitend sind, werden jedoch durch diese Anordnungen keine brauchbaren Ergebnisse erzielt. Auch ist es bei diesen Einrichtungen schwierig, eine Anordnung zu treffen, mit der das Signal nur innerhalb sehr enger Grenzen ausgelöst und eine breite Streuung vermieden wird.With thick-walled pipes, such as those in hydraulic systems are necessary, especially for thick-walled steel pipes that are usually magnetically conductive, but are caused by this Arrangements did not produce useful results. It is too difficult to make an arrangement with these facilities with which the signal is only triggered within very narrow limits and a wide spread is avoided.
Es ist Aufgabe der Erfindung, eine druckmittelbetätigte Zylinder-Kolben-Anordnung der eingangs angegebenen Gattung dahingehend weiterzuentwickeln, die es erlaubt, auch bei verhältnismäßig starkwandigen Zylindern bzw. höheren Drücken ein präzises Wegsignal abzufragen.It is an object of the invention to provide a pressure-operated cylinder-piston arrangement the above-mentioned genus to develop further, which allows it to be proportionate thick-walled cylinders or higher pressures a precise To query the path signal.
Zur Lösung dieser Aufgabe geht die Erfindung aus von der Anordnung der eingangs angegebenen Gattung und schlägt die im kennzeichnenden Teil des ersten Anspruches angegebenen Merkmale vor. To achieve this object, the invention is based on the arrangement of the genus specified at the beginning and beats the in the characterizing Features specified in the first claim in front.
Bei der Erfindung gelangt der Permanentmagnet in unmittelbare Nähe der Innenwandung des Zylinders, ohne diesen zu berühren. Die an einer Seite des Permanentmagneten angeordnete Ringscheibe aus ferromagnetischen Material lenkt den magnetischen Fluß auf kürzestem Wege gegen den Zylinder. Insbesondere wird hierdurch eine Streuung des magnetischen Flusses vermieden, so daß der magnetische Fluß auf einen engen Bereich zusammengedrängt wird.In the invention, the permanent magnet comes into direct contact Close to the inside wall of the cylinder without touching it. The ring disk arranged on one side of the permanent magnet made of ferromagnetic material directs the magnetic Flow along the shortest route against the cylinder. In particular thereby avoiding scattering of the magnetic flux, so that the magnetic flux is confined to a narrow area becomes.
Durch die Anordnung einer Ausnehmung im Zylinder für eine Büchse aus magnetisch nicht leitendem Werkstoff, die den Magnetfeldsensor aufnimmt, läßt sich auch bei Zylindern aus ferromagnetischem Material ein direkter magnetischer Fluß zum Sensor erreichen, wobei eine hohe Feldstärke erzielt wird. Ein entsprechend empfindlicher Sensor wird dann nur auf die ausreichend hohe Feldstärke ansprechen, wodurch Störungen durch Streuung des Magnetfeldes oder auch durch andere Einrichtungen ausgeschlossen werden.By arranging a recess in the cylinder for a Bush made of magnetically non-conductive material that the magnetic field sensor records, can also with cylinders made of ferromagnetic Material a direct magnetic flux to the sensor achieve, whereby a high field strength is achieved. A correspondingly sensitive sensor is then sufficient only on the respond to high field strength, causing interference from Scattering of the magnetic field or by other devices be excluded.
Günstig ist es, wenn der Außendurchmesser der Ringscheibe aus ferromagnetischem Material geringfügig größer ist als der Außendurchmesser des Permanentmagneten. Dadurch wird schon durch die Bauform der Ringscheibe bzw. Ringscheiben eine geeignete Umlenkung des Flusses in Richtung auf die Zylinderwandung erzielt.It is favorable if the outer diameter of the ring disk is made ferromagnetic material is slightly larger than that Outside diameter of the permanent magnet. This will do a suitable one due to the design of the washer or washers Redirection of the flow towards the cylinder wall achieved.
Vorteilhaft ist es, wenn die axialen Abmessungen der Ringscheibe aus ferromagnetischem Material höchstens halb so groß sind als die axialen Abmessungen des Permanentmagneten. Dadurch wird eine Streuung weitgehend vermieden und der Magnetfluß konzentriert.It is advantageous if the axial dimensions of the washer made of ferromagnetic material at most half the size are as the axial dimensions of the permanent magnet. Thereby scatter is largely avoided and the magnetic flux is concentrated.
Die Ringscheiben können axial auf beiden Seiten des Permanentmagneten angeordnet werden. In diesem Fall entsteht ein Magnetfluß im wesentlichen von der einen Ringscheibe zur anderen Ringscheibe. Besser ist es jedoch, wenn nur eine einzige ferromagnetische Ringscheibe auf einer Seite des Permanentmagneten angewandt wird, so daß nur an dieser Stelle das Maximum der Feldstärke erzielt wird, so daß der Sensor nur diese Position anzeigt. In besonderen Fällen kann es jedoch empfehlenswert sein, auch zwei ferromagnetische Ringscheiben zu benützen, wodurch dann je nach Anordnung ein etwas breiterer Bereich des Maximums erhalten wird, oder zwei Spitzen im Bereich der ferromagnetischen Ringscheiben.The washers can be axially on both sides of the permanent magnet to be ordered. In this case there is a magnetic flux essentially from one ring disc to the other Washer. However, it is better if only one ferromagnetic Washer on one side of the permanent magnet is applied so that only at this point the maximum of Field strength is achieved so that the sensor only this position displays. In special cases, however, it can be recommended be to also use two ferromagnetic washers, whereby then, depending on the arrangement, a somewhat wider area of the Maximum is obtained, or two peaks in the field of ferromagnetic Washers.
Mittels der Ringscheiben aus ferromagnetischem Material ist es auch möglich, die Lage des Permanentmagneten zu justieren.It is by means of the ring disks made of ferromagnetic material also possible to adjust the position of the permanent magnet.
Wie erwähnt, ist der Außendurchmesser des Permanentmagneten geringfügig kleiner als der Innendurchmesser des Zylinders. Dies stellt sicher, daß der Permanentmagnet nicht mit der Innenwandung des Zylinders in Berührung kommt, so daß ein Verschleiß am Permanentmagneten verhindert wird. Der dadurch bedingte etwas größere Abstand vom Magnetfeldsensor ergibt keine Nachteile, da die ferromagnetische Ringscheibe hinreichend nahe an die Innenwandung des Zylinders heranreichen kann.As mentioned, the outside diameter of the permanent magnet slightly smaller than the inside diameter of the cylinder. This ensures that the permanent magnet is not compatible with the Inner wall of the cylinder comes into contact, so that wear on the permanent magnet is prevented. The resulting a somewhat larger distance from the magnetic field sensor does not result Disadvantages because the ferromagnetic ring disk is sufficiently close can reach the inner wall of the cylinder.
Nach einem weiteren Merkmal der Erfindung wird vorgeschlagen, daß die Buchse insbesondere aus austenitischem Stahl besteht und in die Ausnehmung eingeschweißt ist und in einer Sackbohrung den Sensor aufnimmt. Es ist klar, daß in besonderen Fällen anstelle der Schweißung auch eine Hartlötung ausreichend sein kann. Durch die eingeschweißte Buchse und die Sackbohrung in der Buchse ist der Innenraum des Zylinders vom Sensor abgetrennt. Der Sensor kann leicht ausgewechselt werden. Die Ausnehmung im Zylinder kann bis in das Innere des Zylinders reichen. In diesem Fall ist es von Vorteil, wenn das Innenende der Buchse zusammen mit der Innenfläche des Zylinders bearbeitet ist. Dieses Vorgehen stellt sicher, daß trotz der eingesetzten Buchse die Innenfläche des Zylinders völlig glatt ist, so daß keine zusätzlichen Beanspruchungen für die Dichtungen entstehen.According to a further feature of the invention, it is proposed that that the bushing consists in particular of austenitic steel and is welded into the recess and in a blind hole picks up the sensor. It is clear that in particular If, instead of welding, brazing is also sufficient can be. Through the welded socket and the blind hole the interior of the cylinder is separated from the sensor in the socket. The sensor can be easily replaced. The recess in the cylinder can go inside the cylinder pass. In this case, it is advantageous if the inner end machined the bushing together with the inner surface of the cylinder is. This procedure ensures that despite the used Bush the inner surface of the cylinder completely smooth is, so that no additional stress for the seals arise.
Die Erfindung schlägt ferner vor, daß der Kolben aus magnetisch nicht oder wenig leitendem Werkstoff besteht. Durch diesen Vorschlag soll vermieden werden, daß der Permanentmagnet im Kolben seinen magnetischen Rückschluß findet, wodurch das Magnetfeld in der Ausnehmung bzw. am Sensor verringert würde. Dabei wurde gefunden, daß eine geringe magnetische Leitfähigkeit für den Werkstoff des Kolbens mindestens nicht nachteilig ist.The invention also proposes that the piston be made of magnetic there is no or little conductive material. With this suggestion should be avoided that the permanent magnet in the piston finds its magnetic return, causing the magnetic field would be reduced in the recess or on the sensor. It was found that low magnetic conductivity for the Material of the piston is at least not disadvantageous.
Der Magnetfeldsensor ist in der Regel fest am Zylinder angeordnet. Die Anordnung kann aber auch derart getroffen werden, daß der Magnetfeldsensor in eine geeignete Ausnehmung längs des Zylinders verschiebbar ist. In diesem Fall läßt sich die Stelle des Kolbens verändern, in der der Magnetfeldsensor das durch den Permanentmagneten des Kolbens ausgelöste Signal abgibt.The magnetic field sensor is usually fixed to the cylinder. The arrangement can also be made such that the magnetic field sensor in a suitable recess along the Cylinder is slidable. In this case, the job can of the piston in which the magnetic field sensor changes that emits the signal triggered by the permanent magnet of the piston.
Es ist gefunden worden, daß es genügt, wenn der Permanentmagnet verhältnismäßig kleine Abmessungen besitzt. So kann die radiale Dicke des Permanentmagneten kleiner als ein Drittel des Radius des Kolbens sein. Insbesondere wurde gefunden, daß die radiale Dicke des Permanentmagneten etwa den sechsten Teil des Radius des Kolbens entsprechen kann, um sehr gute Ergebnisse zu erzielen. Die axialen Abmessungen des Permanentmagneten sind dabei gleich der radialen Dicke oder geringfügig größer.It has been found that it is sufficient if the permanent magnet has relatively small dimensions. So the radial Thickness of the permanent magnet less than a third of the radius of the piston. In particular, it was found that the radial Thickness of the permanent magnet about the sixth part of the radius of the piston to achieve very good results. The axial dimensions of the permanent magnet are same as the radial thickness or slightly larger.
Die axialen Abmessungen der Ringscheibe oder Ringscheiben aus ferromagnetischem Material sind bei einem bevorzugten Ausführungsbeispiel der Erfindung höchstens halb so groß als die axialen Abmessungen des Permanentmagneten. Dies sichert eine geringfügig axiale Ausdehnung des Magnetfeldes und eine entsprechende Genauigkeit der Anzeige durch den Magnetfeldsensor.The axial dimensions of the washer or washers Ferromagnetic material are in a preferred embodiment the invention at most half as large as that axial dimensions of the permanent magnet. This ensures one slightly axial expansion of the magnetic field and a corresponding Accuracy of the display by the magnetic field sensor.
In der Zeichnung ist ein Ausführungsbeispiel der erfindungsgemäßen Zylinder-Kolben-Anordnung schematisch dargestellt.In the drawing is an embodiment of the invention Cylinder-piston arrangement shown schematically.
Die Zylinder-Kolben-Anordnung 1 besteht im wesentlichen aus dem
Zylinder 10, dem Kolben 11 und der Kolbenstange 12. Der
Zylinder ist auf der einen Seite durch den Deckel 13 verschlossen,
der auch die Anschlußleitung 14 trägt. Auf der
anderen Seite ist die Kolbenstangenführung 15 vorgesehen, die
vom Verschlußring 16 gehalten ist. Der zweite Hydraulikanschluß
ist mit 17 bezeichnet.The cylinder-
In der Wandung des Zylinders 10 ist eine Ausnehmung 20 vorgesehen,
in der die Buchse 21 eingesetzt bzw. eingeschweißt
ist. Diese Buchse 21 nimmt in der Sackbohrung 22 den Magnetfeldsensor
2 auf, dessen Anschlüsse mit 23 bezeichnet sind. Der
Magnetfeldsensor kann beispielsweise ein Reed-Schalter sein,
der in einem Schutzrohr untergebracht ist. Besser ist es
jedoch, einen Magnetfeldsensor vorzusehen, der insbesondere
keine beweglichen Teile aufweist und zum Beispiel auf induktivem
Wege das Magnetfeld ermittelt und das entsprechende
Signal abgibt.A
Der Kolben 11 besteht im wesentlichen aus den beiden Teilen 18
und 19. Die Teile 18 und 19 sind auf dem Gewindezapfen 30 der
Kolbenstange 12 gehalten. Durch die zweiteilige Ausbildung des
Kolbens 11 kann in die Ringnut 31 des Teiles 19 der ringförmige
Permanentmagnet 3 eingeschoben werden. Beidseitig des Permanentmagneten
3 sind die Ringscheiben 32 und 33 angeordnet. Der
Permanentmagnet 3 ist parallel zur Mittelachse 39 der Zylinder-Kolben-Anordnung
1 magnetisiert. Beispielsweise zeigt der Nordpol
in Richtung der Kolbenstangenführung 15, der Südpol dagegen
in Richtung des Deckels 13.The
In weiteren Ringnuten 34 und 35 sind, wie an sich bekannt, die
Kolbendichtungen 36 und 37 angeordnet. In further
In der gezeigten Stellung des Kolbens 11 ist der Permanentmagnet
3 bezüglich der Ausnehmung 20 derart angeordnet, daß
sich dieser Permanentmagnet an einer Stelle ganz innerhalb der
Grenzen der Ausnehmung 20 befindet, die die Buchse 21 aufnimmt.
Auf diese Weise wird das Magnetfeld des Permanentmagneten den
Sensor 2 erreichen, so daß ein Wegsignal erhalten wird. Die
Distanz "s" gibt ungefähr an, wie groß der Schaltweg ist. Dabei
ist es gleichgültig, ob sich der Kolben von der einen oder von
der anderen Richtung auf die Ausnehmung zubewegt.In the position shown of the
Die beiden Ringscheiben 32 und 33 können beide aus ferromagnetischem
Material bestehen. Bessere Ergebnisse bzw. ein exakteres
Signal wird jedoch dann erhalten, wenn die eine der Ringscheiben,
beispielsweise die Ringscheibe 32, aus ferromagnetischem
Material besteht, während die andere Ringscheibe entweder
weggelassen wird, wobei dann die Breite der Ringnut 31 zu
verringern wäre, oder wenn diese andere Ringscheibe 33 aus Aluminium,
Messing oder einem ähnlichen Material besteht. Bei
einer solchen Anordnung wird dann der Magnetfeldsensor nur auf
die Lage der einen ferromagnetischen Ringscheibe 32 ansprechen.The two
Claims (10)
- Cylinder piston arrangement, operated by a pressure medium, with a permanent magnet (3) at the piston (11) and a magnetic field sensor (2) at the cylinder (10) for interrogating a path signal where the permanent magnet is annular and magnetized in the direction of the axis of the cylinder piston arrangement, with ring discs (32, 33) made of ferromagnetic material in order to direct the magnetic flux, characterised in that the permanent magnet (3) is arranged in an annular groove (31) of the piston (11) which is open to the outside, where the outside diameter of the permanent magnet (3) is only slightly smaller than the inside diameter of the cylinder (10), that the annular groove (31) takes a ring disc (32) made of ferromagnetic material at one side of the permanent magnet (3), inside and outside diameter of the ring disc corresponding in general to the inside and outside diameter of the permanent magnet (3), and that in the cylinder (10) a recess (20) for a socket (21) of magnetically non-conductive material is arranged which holds the magnetic field sensor (2).
- Cylinder piston arrangement according to claim 1, characterised in that the outside diameter of the ring disc (32) made of ferromagnetic material is slightly bigger than the outside diameter of the permanent magnet (3).
- Cylinder piston arrangement according to one or both of the preceding claims, characterised in that the axial dimensions of the ring disc (32) made of ferromagnetic material are not more than half of the axial dimensions of the permanent magnet (3).
- Cylinder piston arrangement according to one or more of the preceding claims, characterised in that only at one side of the permanent magnet (3) a ring disc (32) made of ferromagnetic material is arranged.
- Cylinder piston arrangement according to one or more of the preceding claims, characterised in that the socket (21) is made of, in particular, austenitic steel and is welded into the recess (20) and holds the sensor (2) in a pocket boring (22).
- Cylinder piston arrangement according to one or more of the preceding claims, characterised in that the inside end of the socket (21) is machined together with the inside plane of the cylinder (10).
- Cylinder piston arrangement according to one or more of the preceding claims, characterised in that the piston (11) is made of a material which is magnetically nonconducting or slightly conductive.
- Cylinder piston arrangement according to one or more of the preceding claims, characterised in that the magnetic field sensor (2) can be shifted in the direction of the axis of the cylinder piston arrangement (1).
- Cylinder piston arrangement according to one or more of the preceding claims, characterised in that the radial thickness of the permanent magnet (3) is smaller than a third of the radius of the piston (11).
- Cylinder piston arrangement according to one or more of the preceding claims, characterised in that the radial thickness of the permanent magnet (3) corresponds to about the sixth part of the radius of the piston (11).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19500137 | 1995-01-04 | ||
| DE19500137A DE19500137A1 (en) | 1995-01-04 | 1995-01-04 | Fluid-operated cylinder-piston arrangement with a magnetic field sensor |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0721067A2 EP0721067A2 (en) | 1996-07-10 |
| EP0721067A3 EP0721067A3 (en) | 1998-02-11 |
| EP0721067B1 true EP0721067B1 (en) | 2002-08-28 |
Family
ID=7750997
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP95120518A Expired - Lifetime EP0721067B1 (en) | 1995-01-04 | 1995-12-23 | Fluid-pressure actuator with a magnetic field sensor |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0721067B1 (en) |
| AT (1) | ATE223002T1 (en) |
| DE (2) | DE19500137A1 (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE29607993U1 (en) * | 1996-05-03 | 1996-08-01 | Festo Kg | Piston for a working cylinder |
| DE19637296A1 (en) * | 1996-09-13 | 1998-03-19 | Wabco Gmbh | Piston / cylinder arrangement |
| DE19712829B4 (en) * | 1997-03-26 | 2005-02-17 | Sick Ag | Device for detecting the position of a moving object |
| DE19752671B4 (en) * | 1997-11-28 | 2006-11-23 | Ludwig Ehrhardt Gmbh | Block cylinder for holding and guiding tools on a machine tool or on a work table |
| DE19756639A1 (en) | 1997-12-19 | 1999-06-24 | Zahnradfabrik Friedrichshafen | Gear changing system for stepped reduction gearbox of vehicle |
| DE19756637A1 (en) * | 1997-12-19 | 1999-06-24 | Zahnradfabrik Friedrichshafen | Gear selection control for transmission |
| DE10053995A1 (en) * | 2000-10-31 | 2002-05-08 | Continental Teves Ag & Co Ohg | Signal generator with Hall sensor integrated in a master cylinder |
| DE10304551A1 (en) * | 2003-02-04 | 2004-08-12 | Mann + Hummel Gmbh | Control element with position detection |
| DE10310428A1 (en) | 2003-03-11 | 2004-09-30 | Hydac Technology Gmbh | piston accumulators |
| DE102005030722A1 (en) * | 2005-07-01 | 2007-01-04 | Bosch Rexroth Teknik Ab | Actuating cylinder used in handling and transport systems comprises a measuring unit with a magnetic field sensor arranged relative to the magnetic field at a specified angle to the main measuring direction |
| CN102943784B (en) * | 2012-11-19 | 2015-06-10 | 湖南特力液压有限公司 | Cylinder barrel, hydraulic cylinder and pumping equipment comprising hydraulic cylinder |
| DE202013010056U1 (en) * | 2013-11-07 | 2015-02-10 | Bümach Engineering International B.V. | working cylinder |
| DE102016210002A1 (en) * | 2016-06-07 | 2017-12-07 | Zf Friedrichshafen Ag | Gearbox with a switching unit |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE8209420U1 (en) * | 1982-04-02 | 1983-09-15 | Robert Bosch Gmbh, 7000 Stuttgart | PISTON FOR CONTACTLESS PISTON POSITION SENSING |
| DE3510601A1 (en) * | 1985-03-23 | 1986-09-25 | Wabco Westinghouse Steuerungstechnik GmbH & Co, 3000 Hannover | Piston unit for a working cylinder, with a device for detecting the piston position |
| CH674058A5 (en) * | 1986-10-22 | 1990-04-30 | Festo Kg | |
| JPS63122902A (en) * | 1986-11-13 | 1988-05-26 | Ckd Controls Ltd | Apparatus for confirming position of moving body |
| DE9010114U1 (en) * | 1990-07-03 | 1990-09-06 | Festo Kg, 7300 Esslingen, De | |
| DE4122481C2 (en) * | 1991-07-06 | 1995-08-31 | Kuhnke Gmbh Kg H | Piston-cylinder arrangement |
| DE9305640U1 (en) * | 1993-04-15 | 1994-08-25 | Hydraulik Techniek | Pressure operated cylinder |
-
1995
- 1995-01-04 DE DE19500137A patent/DE19500137A1/en not_active Withdrawn
- 1995-12-23 EP EP95120518A patent/EP0721067B1/en not_active Expired - Lifetime
- 1995-12-23 DE DE59510348T patent/DE59510348D1/en not_active Expired - Fee Related
- 1995-12-23 AT AT95120518T patent/ATE223002T1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| ATE223002T1 (en) | 2002-09-15 |
| DE19500137A1 (en) | 1996-07-11 |
| EP0721067A3 (en) | 1998-02-11 |
| EP0721067A2 (en) | 1996-07-10 |
| DE59510348D1 (en) | 2002-10-02 |
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