DE102016015057B3 - measuring system - Google Patents

Abstract

Measuring system (10) for detecting a position of a body (100) rotating about a rotation axis (D), comprising a transmitter unit (30), a magnetic field sensor arrangement (20) and an evaluation unit, wherein the magnetic field sensor arrangement (20) comprises a bias magnet (22) and two magnetic field sensors (24, 26) for detecting mutually perpendicular magnetic field component (Hz). The transmitter unit (30) is fixedly connected to the body (100) and has at least one transmitter (32, 34) guided between a minimum and a maximum distance in a linear positive guide (32.1, 34.1), at least one minimum sensor track (36) and at least a maximum value track (38). The minimum value sensor track (36) and the maximum value encoder track (38) each extend at a fixed distance (d3, d4) to the axis of rotation (D) over a first or a second angular range (a1, a2) about the axis of rotation (D). In a projection along the axis of rotation (D), the forced guidance (32.1, 34.1) is arranged between the first and the second angle range (a1, a2), wherein the first and the second angle range (a1, a2) each have a maximum distance of 45 ° to the forced operation (32.1, 34.1) and the minimum value sensor track (36) and the maximum value sensor track (38) of the magnetic field sensor arrangement (20) each provide a limit value.

Description

The invention relates to a measuring system for detecting a position of a body rotating about a rotation axis, comprising a transmitter unit, a magnetic field sensor arrangement and an evaluation unit for evaluating measuring signals of the magnetic field sensor arrangement.

It is known to detect a position of a body rotating about a rotation axis, e.g. a crankshaft or a camshaft or a flywheel, to use a donor pick-up system, wherein the transmitter is attached to the body and is scanned by the fixed pickup. For example, the passing transducer induces a voltage pulse in the transducer.

Such a measuring system, which determines the rotational speed and the angular position of a shaft by means of a transmitter wheel with a plurality of angle encoders, for example, from EP 0 188 433 B1 known.

From the DE 10 2013 021 693 A1 is a working according to the spring-mass principle measuring system for detecting a position or the rotational speed of a rotating body known. Furthermore, from the US 4,713,654 A , of the DE 35 20 928 A1 , of the US 4,027,182 A and the DE 2 855 635 A1 Also known rotational speed sensor devices for detecting the rotational speed of a rotating shaft, and depending on the size of the centrifugal force and masses are moved radially.

Against this background, the object of the invention is to provide a device which further develops the prior art.

The object is achieved by a measuring system having the features of patent claim 1. Advantageous embodiments of the invention are the subject of dependent claims.

According to the subject matter of the invention, a measuring system is provided for detecting a position of a body rotating about a rotation axis. The measuring system has a transmitter unit, a magnetic field sensor arrangement and an evaluation unit for evaluating measuring signals of the magnetic field sensor arrangement.

The magnetic field sensor arrangement comprises a bias magnet for generating a magnetic field, at least one first magnetic field sensor for detecting a magnetic field component parallel to the rotational axis, and a second magnetic field sensor for detecting a magnetic field component perpendicular to the rotational axis; the two magnetic field components are orthogonal.

The first magnetic field sensor and the second magnetic field sensor are each arranged in a fixed position between the bias magnet on the one hand and the rotating body on the other hand. Preferably, the two magnetic field sensors are fixed with respect to the axis of rotation and each have a fixed distance to the axis of rotation.

The two magnetic field sensors are preferably designed as 2-D magnetic field sensors, in particular as Hall sensors. Preferably, the first magnetic field sensor and the second magnetic field sensor each have the same center of gravity.

The transmitter unit is fixedly connected to a surface of the rotating body facing the magnetic field sensor arrangement and has at least one transmitter and at least one linear positive guide for the at least one transmitter.

The one transmitter is guided in the linear positive guide within a first plane radially to the axis of rotation between a first distance and a second distance to the axis of rotation and includes a magnetic material for local variation of the magnetic field.

The first plane is perpendicular to the axis of rotation, wherein the first distance to the axis of rotation is smaller than the second distance to the axis of rotation.

The encoder unit furthermore has at least one minimum value track and at least one maximum value track.

The at least one minimum value sensor track and the at least one maximum value value track each comprise a ferromagnetic material and are arranged between the body and the magnetic field sensor arrangement. The two encoder tracks are designed as Referenzwertgeberspuren.

The at least one minimal encoder track extends radially at a third distance from the axis of rotation over a first angular range about the axis of rotation.

The at least one maximum encoder track extends radially at a fourth distance from the axis of rotation over a second angular range about the axis of rotation, the third distance being less than the fourth distance.

The first angle range and the second angle range are different from each other, ie, the two angle ranges are spaced from each other.

Preferably, the third distance is less than or equal to the first distance and the fourth distance is greater than or equal to the second distance.

The positive guidance of the transmitter is arranged in a projection along the axis of rotation between the first angle range and the second angle range.

The at least one minimum value sensor track and the at least one maximum value value track each deliver a constant reference value during a rotational movement of the body of the magnetic field sensor arrangement.

Preferably, the two reference values each represent a limit value.

It should be noted that the encoder tracks are each formed as extending along or over a circular arc around the axis of rotation body. It is understood that the encoder tracks each have over their entire length, so the arc a fixed distance to the axis of rotation.

By arranging the minimum value sensor track and the maximum value sensor track on one side of the sensor in a projection along the rotation axis, a signal of one of the sensor tracks is detected by the magnetic field sensor arrangement before and after the signal generated by the sensor during the rotation of the body.

As a result, the transmitter unit supplies, for each measured value, a measured value range enclosed by the upper limit value and the lower limit value. Preferably, the position of the transmitter in the positive control moves between the lower limit and the upper limit

It is further noted that acts on the at least one transmitter upon rotation of the body, a centrifugal force.

It is understood that a ray denotes a straight line starting at a point.

With the measuring system, i. From the two measured values of the two magnetic field sensors, the position of the at least one sensor can be determined relative to the axis of rotation.

From the position, i. From the deflection of the encoder can be determined from the angular velocity of the body whose speed and / or rotational angle of the body.

An advantage of the device according to the invention is that by the reference tracks in addition to the very precise determination of the speed and an imbalance, i. Precisely a vibration of the rotating body can be determined. In this way, it is also possible to conclude on a load of bearings of the body and if necessary to derive corrective measures. Preferably, the body comprises a flywheel arranged on a shaft. Temperature-related expansions of the body can also be detected precisely.

In a further development, the transmitter unit has at least two transducers. In another development, the two transducers are arranged point-symmetrical to the axis of rotation. In one embodiment, the two transducers are arranged opposite one another with regard to the axis of rotation.

An advantage of two transducers is that the measurement accuracy increases even in terms of time. In particular, the speed and changes in the speed and the angle of rotation of the body relative to the version with only one transmitter can be determined more precisely. Also, vibrations can be detected faster and more accurately.

In another embodiment, both sensors are constructed identically.

In another embodiment, the transmitter unit has at least one controlled transmitter, wherein the transmitter is connected to a control unit in a hydraulic and / or electrical and / or electromechanical operative connection.

By means of the control unit can generate a force. It is understood that the force can be generated hydraulically and / or electrically and / or electromechanically or purely mechanically.

The actuating force causes the position of the at least one transmitter to be set both as a function of the rotational speed and independently of the rotational speed in the linear forced operation. In other words, even with a speed of zero, the position of the transmitter can be easily changed with the actuating force, i. The transmitter can be moved away from the axis of rotation as well as to move on the axis of rotation.

One advantage is that with the controlled transmitter vibrations of the rotating body counteracts. For this purpose, the position of the transmitter is changed by means of the adjusting force, in particular to suppress vibrations and to reduce the wear of bearings.

It is understood that without the force on the transmitter at a speed greater than zero, at least the centrifugal force acts, wherein without a force or in particular a restoring force of the transmitter moves away with increasing speed from the axis of rotation.

In a development, the actuating force is designed as a restoring force. Preferably, the restoring force is proportional or non-proportional to the centrifugal force.

In one embodiment, the restoring force is effected by means of a spring element or a hydraulic return device.

Preferably, the two transducers are connected by means of a spring. In another development, each transmitter has its own adjusting device, in particular a reset device. Preferably, the return device each comprises a spring. In order to change the actuating force in this case, the restoring device or the spring element is connected to a control device.

As a result, the return device can be controlled or regulated. Preferably, the height of the force can be changed. In a further development, the actuating force is changed as a function of the rotational speed.

In particular, can be adjusted with the control device, the height of the actuating force such that the transmitter moves away from the closest position with respect to the axis of rotation only above a minimum speed along the linear positive guidance of the axis of rotation.

In another development, the force is quantized. As a result, regions of the centrifugal force or the speed of rotation of the transducers can also be assigned in a simple manner. In other words, the transmitter moves away from the axis of rotation only in steps.

By means of the reference tracks, the sensitivity of the magnetic field sensor to mechanical tolerances, such as axial offset, vibrations or temperature-induced expansions is reduced and ensures a high accuracy of measurement.

In a development, the first angle range and the second angle range each have a distance of at most 45 °, preferably at most 15 ° or at most 5 °, to the positive guidance.

According to an alternative development, the transmitter unit has at least two minimum value sensor tracks and at least two maximum value encoder tracks.

• 1 eine schematische Aufsicht auf eine erste erfindungsgemäße Ausführungsform eines Messsystems,
• 2 eine schematische Seitenansicht eines mittleren Ausschnitts der ersten erfindungsgemäßen Ausführungsform des Messsystems,
• 3 eine schematische Ansicht eines über die Zeit aufgetragenen Messsignals des Messsystems,
• 4 eine schematische Ansicht einer zweiten Ausführungsform einer erfindungsgemäßen Gebereinheit.

The invention will be explained in more detail with reference to the drawings. Here similar parts are labeled with identical names. The illustrated embodiments are highly schematic, ie the distances and the lateral and vertical extensions are not to scale and, unless otherwise indicated, also have no derivable geometrical relations to one another. It shows:

• 1 a schematic plan view of a first embodiment of a measuring system according to the invention,
• 2 FIG. 2 a schematic side view of a middle section of the first embodiment of the measuring system according to the invention, FIG.
• 3 FIG. 2 a schematic view of a measuring signal of the measuring system applied over time, FIG.
• 4 a schematic view of a second embodiment of a transmitter unit according to the invention.

The pictures of the 1 and 2 show schematically in a plan view or at least partially a side view of a first embodiment of a measuring system 10 for detecting a position of a rotating about a rotation axis D body 100 , For example, a flywheel.

The measuring system has a magnetic field sensor arrangement 20 , a transmitter unit 30 and an evaluation unit (not shown) for evaluating measurement signals of the magnetic field sensor arrangement.

The magnetic field sensor arrangement 20 has a bias magnet 22 for generating a magnetic field H, at least one first magnetic field sensor 24 for detecting a parallel to the rotational axis D extending magnetic field component Hz and a second magnetic field sensor 26 for detecting a perpendicular to the rotation axis D extending magnetic field component Hy on.

The first magnetic field sensor 24 and the second magnetic field sensor 26 are respectively spaced from the axis of rotation D between the bias magnet 22 on the one hand and the rotating body 100 arranged on the other hand.

The transmitter unit 30 is fixed to one of the magnetic field sensor arrangement 20 facing first surface 102 of the body 100 connected. According to the illustrated embodiment, the first surface extends 102 perpendicular to the axis of rotation D.

The transmitter unit 30 has two transducers 32 and 34 and a minimum value track 36 and a maximum value track 38 on.

The two transducers 32 and 34 as well as the minimum value track 36 and the maximum value track 38 are each on the first surface 102 and spaced from the axis of rotation D arranged.

The two transducers 32 and 34 are each in a linear forced operation 32.1 respectively. 34.1 along the surface 102 of the body 100 guided radially to the axis of rotation D between a first distance d1 and a second distance d2 to the axis of rotation D, wherein the first distance d1 is smaller than the second distance d2. The two linear forced tours 32.1 and 34.1 are mirrored to the axis of rotation.

The two transducers 32 and 34 be by a force along the two linear positive guides 32.1 and 34.1 moved away from the axis of rotation and vice versa. For this purpose, the transmitter is connected to a not shown, the force generating control unit in conjunction.

The two transducers 32 and 34 as well as the minimum value track 36 and the maximum value track 38 consist at least partially of a ferromagnetic material, by the bias magnet 22 locally generated magnetic field H to change.

The minimum value track 36 extends at a third distance d3 to the axis of rotation D on the first surface 102 and extends between the two transducers 32 and 34 over a first angular range a1 about the rotation axis D.

The second maximum encoder track 38 has a fourth distance d4 to the axis of rotation D and extends over a second angular range a2 about the axis of rotation D, wherein the second angular range a2 corresponds to a reflection of the first angular range a1 at the axis of rotation D.

According to the illustrated embodiment, the third distance d3 is smaller than the first distance d1 and the fourth distance d4 is greater than the second distance d2.

In the picture of the 3 a measurement signal S of the measuring system is plotted over the time t, wherein the distance of the transmitter to the rotation axis is determined from the measurement signal S and by means of the evaluation unit from the measured values of the two magnetic field sensors 24 . 26 the magnetic field sensor arrangement 20 is calculated. By the rotation of the body 100 The minimal encoder track 36, the first measuring transmitter, is periodically successively about the axis of rotation D. 32 , the maximum value track 38 and the second transmitter 34 at the two magnetic field sensors 24 and 26 the magnetic field sensor arrangement 20 past. In 3 can be seen as each through one of the two transducers 32 and 34 generated measurement signals M ₁ , M ₂ , M ₃ from one by means of the minimum value track 36 generated lower limit G ₁ and a generated by means of the maximum encoder track 38 upper limit G _{2 is} framed.

In an embodiment not shown, the first transmitter 32 and the second transmitter 34 each active connection to a control unit, not shown. The active compound can be formed hydraulically and or electrically. With the control unit, the height and the direction of the force can be adjusted and thereby the position of the transmitter.

In one embodiment, not shown, the actuating force is formed as a restoring force comprising preferably a spring element.

In the picture of the 4 is another embodiment of a transmitter unit according to the invention 30 shown. The following are just the differences from the illustration of 1 explained.

The two transducers 32 and 34 are by a spring element 40 so coupled with each other on every transmitter 32 . 34 each acting towards the center of rotation and a centrifugal force counteracting radial restoring force acts.

Claims (11)

Measuring system (10) for detecting a position of a about an axis of rotation (D) rotating body (100), comprising a transmitter unit (30), a magnetic field sensor arrangement (20) and an evaluation unit for evaluating measurement signals of the magnetic field sensor arrangement (20), wherein - the magnetic field sensor arrangement (20) a bias magnet (22) for generating a magnetic field (H), at least one first magnetic field sensor (24) for detecting a parallel to the rotation axis (D) extending magnetic field component (Hz) and a second magnetic field sensor (26) for detecting a magnetic field component (Hy) running perpendicular to the axis of rotation (D), the first magnetic field sensor (24) and the second magnetic field sensor (26) each between the bias Magnets (22) on the one hand and the rotating body (100) on the other hand are arranged, - the transmitter unit (30) fixed to a magnetic field sensor arrangement (20) facing surface of the body (100) is connected, - the transmitter unit (30) at least one transmitter ( 32, 34) and at least one linear positive guide (32.1, 34.1) for the transmitter (32, 34), - the at least one transmitter (32, 34) in the linear positive guide (32.1, 34.1) within a first plane radially to the The axis of rotation (D) between a first distance (d1) and a second distance (d2) is guided to the axis of rotation (D) and for local change of the magnetic field (H) comprises a ferromagnetic material, - the first plane perpendicular to the axis of rotation (D ), - the first distance (d1) is smaller than the second distance (d2), characterized in that - the transmitter unit (30) has at least one minimum value sensor track (36) and at least one maximum value sensor track (38), - e at least one minimum value sensor track (36) and the at least one maximum value sensor track (38) each comprise a ferromagnetic material and are arranged between the body (100) and the magnetic field sensor arrangement (20), - the at least one minimum value track (36) lies at a third distance ( d3) to the axis of rotation (D) over a first angular range (a1) about the axis of rotation (D), - the at least one maximum encoder track (38) at a fourth distance (d4) to the axis of rotation (D) over a second angular range ( a2) extends about the axis of rotation (D), - the third distance (d3) is smaller than the fourth distance (d4), - the linear positive guide (32.1, 34.1) of the transmitter (32, 34) in a projection along the axis of rotation ( D) is arranged between the first angular range (a1) and the second angular range (a2), wherein the first angular range (a1) and the second angular range (a2) each have a maximum distance of 45 ° to the linear positive guide (32.1, 3 4.1) and - the at least one minimum value sensor track (36) and the at least one maximum value sensor track (38) each deliver a limit value (G ₁ , G ₂ ) during a rotational movement of the body of the magnetic field sensor arrangement (20). Measuring system (10) after Claim 1 , characterized in that the third distance (d3) is less than or equal to the first distance (d1) and the fourth distance (d4) is greater than or equal to the second distance (d2). Measuring system (10) after Claim 1 or Claim 2 , characterized in that the first angular range (a1) and the second angular range (a2) in a projection along the axis of rotation (D) each have a distance of at most 15 ° or at most 5 ° to the linear positive guide (32.1, 34.1). Measuring system (10) according to one of Claims 1 to 3 , characterized in that the transmitter unit (30) has at least two transducers (32, 34). Measuring system (10) after Claim 4 , characterized in that the transducers (32, 34) are arranged point-symmetrical to the axis of rotation (D). Measuring system (10) according to any one of the preceding claims, characterized in that the transmitter unit (30) has at least two minimal encoder tracks (36) and at least two maximum encoder tracks (38). Measuring system (10) according to one of the preceding claims, characterized in that the first magnetic field sensor (24) and the second magnetic field sensor (26) of the magnetic field sensor arrangement (20) in each case to the rotational axis (D) are arranged spaced. Measuring system (10) according to one of the preceding claims, characterized in that the transmitter unit (30) has at least one controlled transmitter (32, 34) and the transmitter (32, 34) with a control unit in a hydraulic and / or electric and / or electromechanical operative connection stands. Measuring system (10) after Claim 8 , characterized in that by means of a control force generated by the control unit, the position of the at least one transmitter (32, 34) both depending on the speed and independent of the speed in the linear forced operation set. Measuring system (10) after one Claims 1 to 7 , characterized in that the transmitter unit (30) comprises at least one spring element (40), wherein the at least one spring element (40) with a first end to the at least one transmitter (32, 34) is fixed and a second end of the spring element (40 ) is held at a position along a beam passing through the transducer (32, 34) through the axis of rotation (D). Measuring system (10) after Claim 10 , characterized in that the at least one transmitter (32, 34) has a restoring force in the direction of Rotary axis (D) experiences and the restoring force on the size of the centrifugal force depends.

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