DE102010029870A1 - sensor - Google Patents

Abstract

Sensor (1) for detecting the axial position of an axially displaceable measurement object (2) which is rotatable about an axis of rotation (A), the sensor (1) having a sensor (5) with a first element (6) and a magnetic element (7) , by means of which a second element (8) of the transducer (5), which cooperates with the first element (6) for position signaling in the case of linear relative movement and is linearly movable relative to the first element (6), is formed, which can be carried without contact for position signaling as a result of linear relative movement , in particular by a measurement object (2).

Description

The present invention relates to a sensor according to the preamble of claim 1.

To determine the axial position of a rotatable about an axis of rotation or shaft and along the shaft axially displaceably mounted body or object, z. B. a pulley of a CVT transmission (continuously variable transmission), in the prior art, a device according to the document DE 195 22 840 A1 proposed. In the known device, the pulley z. B. such that evenly distributed on the peripheral surfaces of the pulley several trapezoidal markings are applied or introduced, the width varies in the circumferential direction along the axial extent. With axial displacement of the pulley signals of different shape can be formed corresponding to the instantaneous axial position of the pulley in a scanning signal generator. Such a sensing device, in which the pulley is formed specifically in the manner described above, however, is costly or can be realized only with great effort.

Proceeding from this, the present invention has the object to provide a sensor which overcomes the disadvantages of the prior art, and is suitable for detecting the axial position of a rotating about an axis measuring object and is easy and inexpensive to implement.

This object is achieved by the features of claim 1.

According to the invention, a sensor is provided for detecting the axial position of an axially displaceable object which is rotatable about an axis of rotation, wherein the sensor has a sensor with a first element and a magnetic element, by means of which a sensor cooperating with the first element for position signaling in linear relative motion, relative to first element defined linearly movable second element of the pickup is formed, which is for positional signaling due to linear relative movement without contact, in particular magnetic, entrained, in particular by a measurement object.

In one embodiment of the invention, only the magnetic element forms the second element of the transducer.

In a further embodiment of the invention, an inductive, a capacitive or a magnetic field sensor can be formed by means of the first and the second element.

According to one aspect of the sensor according to the invention, the first element forms a sensor or a first electrode, wherein the second element forms an actuator of the sensor cooperating with the sensor for position signaling or a second electrode of the sensor.

According to a further aspect of the sensor according to the invention, the second element forms a damping element of an inductive position sensor, the first element in particular having a planar coil.

According to yet another aspect of the sensor according to the invention, the second element is accommodated in a sensor housing, in particular defined linearly movable relative to this. In this case, the first element is arranged relative to the sensor housing in particular positionally stable.

In an embodiment according to the invention of the sensor, the second element is guided in a linearly movable manner relative to the first element by means of the sensor housing.

According to the invention, a sensor is also proposed, sensor electronics being electrically connected to the first or the first and second elements, the sensor electronics being accommodated together with the second element and the first element in a sensor housing.

The invention also proposes a sensor-measuring object arrangement with a sensor according to the invention and a measuring object arranged adjacent to the sensor, in particular with respect to this non-contact measuring object, wherein the second element of the sensor is magnetically entrainment-free by the measuring object, in particular in an axial direction of movement of the measurement object.

In an embodiment according to the invention of the sensor-measurement object arrangement, the measurement object for entraining the second element is formed at least partially magnetizable.

In a further embodiment of the sensor-measuring object arrangement according to the invention, the measurement object is rotatably mounted about an axis and movable in the axial direction, wherein the axial direction corresponds to the direction in which the second element is linearly movable relative to the first element.

Also proposed according to the invention is a CVT transmission with a pulley rotatably mounted on a shaft and axially displaceable, wherein an inventive sensor for detecting the axial position of the Pulley is arranged on the transmission, wherein the pulley forms the measurement object.

Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, with reference to the figures of the drawings, which show details essential to the invention, and from the claims. The individual features can be realized individually for themselves or for several in any combination in a variant of the invention.

Preferred embodiments of the invention are explained below with reference to the accompanying drawings. Show it:

1 exemplarily a sectional view of an arranged on an axially displaceable measuring object sensor according to a possible embodiment of the invention;

2 according to the sensor 1 arranged on a measuring object in the form of an axially displaceable pulley of a CVT transmission;

3 exemplarily a sensor in a broken sectional view according to another possible embodiment of the invention;

4 exemplarily a sensor according to yet another possible embodiment of the invention; and

5 exemplary and schematically an inductive position sensor according to 1 in a translucent view, wherein the sensor is disposed adjacent to an axially displaceable pulley of a CVT transmission.

In the following description of the figures, the same elements or functions are provided with the same reference numerals.

1 shows an example of a sensor according to the invention 1 which is used to detect the axial position of one about an axis A ( 2 ) arranged rotatably and axially (double arrow in the X direction in 2 ) movable measurement object 2 is provided. The sensor 1 According to the invention, it is designed with an at least partially magnetizable measuring object 2 , in particular a ferromagnetic or soft magnetic object to be measured 2 to act together to detect the position of the same. According to the invention, the sensor 1 also for position detection of only linearly movable (axially displaceable) measuring objects 2 suitable. The measurement object 2 is z. B. a conical disk or pulley 3a a CVT transmission (Continuously Variable Transmission), which in 2 is shown.

Such a CVT transmission has, in a known manner, two each on a shaft 4 recorded couples (in 2 only one pair is shown) in an axial direction X of opposed pulleys 3a . 3b on, between the pulley pairs a belt or alternatively z. B. a chain can be guided or guided, the (the) drainage radius between two conical disks 3a . 3b a pair each by the axial distance of the conical disks 3a . 3b is adjustable to one another, such that the transmission ratio of the CVT transmission is adjustable (continuously variable transmission).

The continuously variable CVT transmission has a pulley 3a in each case one pair in the axial direction X towards the respective other conical disk or pulley 3b of the pair or away from it, in particular during a rotation thereof. The instantaneous axial position of such a slidable pulley 3a or a measurement object 2 can by means of the inventive sensor 1 , which is designed as a linear position sensor, can be detected, in particular in order to infer the current transmission ratio of the CVT transmission.

The sensor 1 has according to the invention a pickup 5 with a first element 6 and a magnetic element 7 on, by means of which one with the first element 6 for position signaling in linear relative motion cooperating, relative to the first element 6 defines linearly movable second element 8th of the pickup 5 is formed, which is for positional signaling due to linear relative movement without contact, in particular magnetic, entrained, in particular by a measurement object 2 ,

The first element 6 of the sensor 1 works with the second element 8th of the sensor 1 for position signaling by linear relative movement of the first element 6 and the second element 8th together. The first element 6 and the second element 8th together form a linear position sensor of the sensor 1 ie a pick-up 5 for position measurement. With a linear movement of the second element 8th relative to the first element 6 will be in the sensor 1 a position signal by means of the first 6 and second 8th Element generated, which corresponds to the relative position of the same to each other. The second element 8th is the first element 6 According to the invention defined linear relative movable, ie on a predetermined linear path of movement relative to the first element 6 with a fixed beginning and end, ie with a given range of motion.

This can be z. B. can be achieved by a guide, which in particular the sensor 1 having, and by means of which the second element 8th relative to the first element 6 is guided linearly movable. The second element 8th is relative to the first element 6 in particular exclusively defined linearly movable, ie the second element 8th is to another relative movement with respect to the first element 6 not able (only linear motion path).

The first 6 and the second 8th Element form as first members in a measuring chain together the transducer 5 , wherein the second element 8th by means of the magnetic element 7 is formed, ie for non-contact driving or for contactless driving and for position signaling by means of the same. By means of the magnetic element 7 is the second element 8th z. B. relative to the first element 6 defined guided linearly movable.

The second element 8th works with the first element 6 which z. B. is a sensor, for position signaling together and forms, for example, one with the first element 6 cooperating actuator. The first element 6 Alternatively, for example, a sensor electrode of the pickup 5 , which is connected to a sensor electronics, the second element 8th , which with the first element 6 interacts, forms alternatively z. B. another sensor electrode of the pickup 5 which is also electrically connected to the sensor electronics and which with the first sensor electrode of the pickup 5 for positional signaling due to linear relative movement cooperates.

The second element 8th is by means of the magnetic element 7 , z. B. in the form of a permanent magnet or possibly an electromagnet, without contact mitnehmbar relative to the first element 6 defined formed linearly movable, in particular by a measurement object 2 entrained. The magnetic element 7 of the second element 8th forms a mitnehmbares element, which due to the between the magnetic element 7 and the measurement object 2 acting magnetic attraction forces within the defined movement possibility of the second element 8th is linearly movable, ie only magnetically contactless mitnehmbar, ie directly by the measurement object 2 ,

With reference to the figures, various embodiments of the sensor according to the invention are described below 1 explained by way of example.

1 shows a sensor according to the invention 1 , which as an inductive sensor 1 is formed and in which by means of the first 6 and second 8th Element an inductive pickup 5 is formed. The first element 6 is, for example, a sensor in the form of one or more planar coils 9 , which for position signaling with the second element 8th interact. The second element 8th forms an actuating element, which by means of the magnetic element 7 relative to the first element 6 Non-contact defined linearly movable.

To form such an actuating element or second element 8th is for example a damping element 10 with the magnetic element 7 connected or alternatively formed integrally therewith, z. B. a Bedämpfungselement 10 in the form of a metallic plate. Such a damping element 10 , z. B. in the form of a diamond-shaped plate, z. In 5 shown schematically. The damping element 10 is z. B. at a the sensor or the first element 6 facing side of the magnetic element 7 arranged.

The planar coils 9 of the first element 6 , which in particular in the defined linear relative direction of movement to each other according to z. B. 5 are adjacent, are traversed by high frequency alternating current, which when approaching the damping element 10 Eddy currents caused within it, resulting in a damping of the planar coil 9 and thus lead to a changed inductance value thereof, the evaluation of which results in the output of a position signal corresponding to the position of the damping element 10 , ie the second element 8th relative to the at least one planar coil 9 allows. The planar coils 9 are with a sensor electronics 11 electrically connected, which for supplying the coils 9 with electrical energy and z. B. for processing by means of the first 6 and second 8th Element generated measuring signals, corresponding to their relative position, is provided.

The second element 8th has along its predetermined linear path of movement between a fixed beginning and end in particular constant distance to the (radially) adjacent element 6 on, ie radial direction in 1 so that positional signaling is not adversely affected by varying distance. By means of the through the measuring object 2 non-contact mitnehmbaren magnetic element 7 of the second element 8th can the sensor 1 especially despite large distances to a target 2 make an exact position determination.

At the in 1 shown embodiment of the sensor 1 In particular, all sensor components are advantageous in a housing or sensor housing 12 recorded, ie the sensor electronics 11 as well as first 6 and second 8th Element, wherein the sensor housing 12 in addition to a protection and possibly support functionality at the same time z. B. a guide for the magnetic element 7 of the second element 8th forms, by means of which the second element 8th relative to the first element 6 defines linear is mobile. The first element 6 is immovable or relative to the sensor housing 12 positionally stable with the sensor housing 12 connected or received therein, z. B by means of a printed circuit board, to which z. B. also the sensor electronics 11 can be arranged while the second element 8th relative to linearly movable in the sensor housing 12 is arranged, ie also relative to the sensor housing 12 defines linearly movable. The beginning and end of a linear motion path as well as the path of movement between them is for the second element 8th z. B. in each case by means of the housing wall of a lower housing portion 12a given, for example, in its cross section with that of the second element to be guided 8th , z. B. its magnetic element 7 which corresponds to its leadership.

The sensor 1 is ( 1 ) aligned on the measurement object 2 arranged that the direction in which the second element 8th relative to the first element 6 defined linearly movable, with the axial direction of movement of the measurement object 2 matches (X direction). Furthermore, the magnetic element 7 to the particular ferro- or soft magnetically formed measurement object 2 arranged in the radial direction adjacent to this, in order to be able to be taken by this without contact. During a movement of the DUT 2 in the axial direction X, the second element moves 8th consequently together with the measurement object 2 relative to the first element 6 defines linear, in the present case between the first 12b and second 12c front-side housing wall, in particular parallel to the first element 6 at a constant distance. In general, the invention provides a defined linear movement of the magnetic element 7 or the second element 8th relative to the first element 6 to the extent possible, which with the axial travel of the measuring object 2 corresponds, within which a position determination is to take place.

3 shows a broken cross section through a sensor 1 an alternative embodiment in which the second element 8th by means of the magnetic element 7 relative to the first element 6 defined linearly movable and contactless mitnehmbar is formed. The sensor 1 here has a guide element for defining the movement path 13 which extends in the linear direction of the travel, e.g. B. a profile or a rail, and which with a guide element 14 of the magnetic element 7 cooperates, z. B. a corresponding profile groove.

At the in 3 embodiment shown forms the magnetic element 7 the second element 8th of the pickup 5 , ie exclusively. In such an embodiment, the first element is 6 z. B. a Hall element, relative to which the magnetic element 7 as an actuating element without contact mitnehmbar defines linearly movable and z. B. provides a magnetic field, which in terms of at least one directional component, in z. B. radial direction, from the Hall element, z. As a Hall IC in the form of a transversal detector is detectable. Alternatively, by means of the first 6 and second 8th Element for example a magnetoresistive sensor 1 educated. Generally, by the first 6 and the second 8th Element or the magnetic element 7 for example, a magnetic field transducer 5 be formed.

4 shows a further embodiment of the invention, in which the sensor 1 z. B. as a capacitive sensor 1 is formed. The first element 6 is in the form of a rod-shaped first electrode 16 formed, which with the sensor electronics 11 , in particular fixed, is connected. With the first electrode 16 For position signaling, the second element acts 8th a capacitive transducer 5 by means of a second, formed as a hollow tube, electrode 17 the same, in which the first electrode 16 immersed in a defined linear motion The second electrode 17 is, for. B. by means of an electrical line 17a , also with the sensor electronics 11 connected. At the second electrode 17 is the magnetic element 7 forming the second element 8th permanently and rigidly connected or alternatively formed integrally therewith, so that the electrode 17 in a contactless entrainment of the magnetic element 7 through a measuring object 2 relative to the first electrode 16 defined linearly can be moved. Depending on the state of immersion, the capacity of the first one changes 16 and second 17 Electrode formed capacitor array or capacitive sensor, such that by the sensor electronics 11 a relative position can be determined, which with a position of the measurement object 2 corresponds.

In this arrangement, a defined relative linear movement, for example, be achieved that the second 8th Element the first element 6 , with z. B. a dielectric, contacting the first element 6 is guided, wherein z. B. the first electrode 16 ie the first element 6 , at one, z. B. vertically oriented sensor electronics 11 is supported (beginning of the movement path) and at an unsupported end a stop for the second electrode 17 has (not shown, end of travel), which at the first electrode 16 trapped. A housing 12 is z. B. dispensable.

The sensor according to the invention 1 allows a measurement of the position even at large distances of the sensor 1 to the measurement object 2 or to a particular rotating component. A compensation of the rotational speed and a possible aging of a storage, which Vibration leads, can thus be compensated. In general, according to the invention, various transducers or sensors can be formed, which use two mutually defined linearly displaceable elements for positional signaling.

LIST OF REFERENCE NUMBERS

1

sensor

2

measurement object

3a, 3b

pulley

4

wave

5

pickup

6

first element

7

magnetic element

8th

second element

9

planar coil

10

damping element

11

sensor electronics

12

sensor housing

12a

lower housing section

12b, c

frontal housing wall

13

Guide element housing

14

Guide element magnetic element

15

Hall element

16

first electrode

17

second electrode

17a

electrical line

A

axis of rotation

X

axial direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19522840 A1 [0002]

Claims (12)

Sensor ( 1 ) for detecting the axial position of an axially displaceable measuring object which is rotatable about an axis of rotation (A) ( 2 ), characterized in that the sensor ( 1 ) a transducer ( 5 ) with a first element ( 6 ) and a magnetic element ( 7 ), by means of which a with the first element ( 6 ) for position signaling in linear relative motion cooperating, relative to the first element ( 6 ) defines linearly movable second element ( 8th ) pickup ( 5 ) is formed, which is mitnehmlos for positional signaling due to linear relative movement without contact, in particular by a measuring object ( 2 ). Sensor ( 1 ) according to claim 1, characterized in that only the magnetic element ( 7 ) the second element ( 8th ) of the transducer ( 5 ). Sensor ( 1 ) according to one of the preceding claims, characterized in that by means of the first ( 6 ) and the second ( 8th ) Element is an inductive, capacitive or magnetic field transducer ( 5 ) is bildbar. Sensor ( 1 ) according to one of the preceding claims, characterized in that the first element ( 6 ) a sensor or a first electrode ( 16 ) and the second element ( 8th ) an actuator of the sensor cooperating with the position signaling probe ( 1 ) or a second electrode ( 17 ) of the transducer ( 5 ). Sensor ( 1 ) according to one of the preceding claims, characterized in that the second element ( 8th ) a damping element ( 10 ) of an inductive position sensor ( 1 ), the first element ( 6 ), in particular a planar coil ( 9 ) having. Sensor ( 1 ) according to one of the preceding claims, characterized in that the second element ( 8th ) in a sensor housing ( 12 ), in particular defined relative to this linearly movable. Sensor ( 1 ) according to one of the preceding claims, characterized in that the second element ( 8th ) by means of the sensor housing ( 12 ) relative to the first element ( 6 ) Defined linearly movably guided. Sensor ( 1 ) according to one of the preceding claims, characterized in that a sensor electronics ( 11 ) with the first ( 6 ) or the first ( 6 ) and second ( 8th ) Element is electrically connected, wherein the sensor electronics ( 11 ) together with the second element ( 8th ) and the first element ( 6 ) in a sensor housing ( 12 ) is recorded. Sensor-measuring object arrangement with a sensor ( 1 ) according to one of the preceding claims and one adjacent to the sensor ( 1 ) measured object ( 2 ), characterized in that the second element ( 8th ) of the sensor ( 1 ) of the measured object ( 2 ) is non-contact magnetically entrainable, in particular in an axial direction of movement (X) of the measurement object ( 2 ). Sensor-measuring object arrangement according to claim 9, characterized in that the measuring object ( 2 ) to take the second element ( 8th ) is formed at least partially magnetizable. Sensor-measuring object arrangement according to one of claims 9 or 10, characterized in that the measured object ( 1 ) is rotatably mounted about an axis (A) and movable in the axial direction (X), wherein the axial direction (X) corresponds to the direction in which the second element ( 8th ) relative to the first element ( 6 ) is linearly movable. CVT transmission with one on a shaft ( 4 ) rotatably mounted and axially displaceable pulley ( 3a ), characterized in that a sensor ( 1 ) according to one of the preceding claims for detecting the axial position of the pulley ( 3a ) is arranged on the transmission, wherein the pulley ( 3a ) the measuring object ( 2 ).

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