WO1991003709A1 - Measuring device for travel or angle of rotation - Google Patents

Measuring device for travel or angle of rotation Download PDF

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Publication number
WO1991003709A1
WO1991003709A1 PCT/DE1990/000609 DE9000609W WO9103709A1 WO 1991003709 A1 WO1991003709 A1 WO 1991003709A1 DE 9000609 W DE9000609 W DE 9000609W WO 9103709 A1 WO9103709 A1 WO 9103709A1
Authority
WO
WIPO (PCT)
Prior art keywords
sleeve
coil
characterized
coils
device according
Prior art date
Application number
PCT/DE1990/000609
Other languages
German (de)
French (fr)
Inventor
Klaus Dobler
Hansjörg Hachtel
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to DEP3929681.4 priority Critical
Priority to DE19893929681 priority patent/DE3929681A1/en
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO1991003709A1 publication Critical patent/WO1991003709A1/en

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/20Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
    • G01D5/22Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature differentially influencing two coils
    • G01D5/2208Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature differentially influencing two coils by influencing the self-induction of the coils

Abstract

In a measuring device (10) for determining the travel or angle of rotation of a machine component (21), one coil (19) is arranged on a sleeve-like body (16) and another (20) on a cylindrical body (17). The sleeve (16) and the core (17) are on a support (15). The core (17) engages in a sleeve (13) of non-ferromagnetic but electrically conductive material. In addition, the sleeve (16) is taken over a core (12) of ferromagnetic material. Here, the coil body (16) and the core (12) and the coil body (17) and the sleeve (13) are coaxial. Owing to the eddy current effect, the inductance in the coil (20) is reduced, while on account of the ferromagnetic effect the inductance in the coil (19) is increased. Errors of measurement can be partly eliminated and the measurement signal amplified through the cross-connection of the coils (19, 20) in an evaluation circuit.

Description

Measuring means for detecting a rotation angle or a Weσs

State of the art

The invention proceeds from a device for detecting a displacement or a rotation angle according to the preamble of the main claim. A movable measuring element is moved relative to the two coaxial Me߬ element disposed sensing coils. By the movement of the measuring element, the Uberdeckungsverhaltnis between one coil and the measuring element is increased while it is decreased by the same amount between the other coil and the measuring element. This device has a relatively large overall length, though only a relatively short measuring distance can be detected.

Advantages of the Invention

In contrast, the device of the invention with the characterizing features of the main claim has the advantage that it is very compact and has a relatively small axial length. Especially when the core of ferromagnetic material is inserted into the cylindrical coil configured, a high measuring signal can be achieved when the ferromagnetic effect. the measuring effects of the coils are oppositely directed operation by the change of the coil inductance while Me߬ added while occurring measuring errors of the individual coils will often get in each other largely kompensieren.Das measurement signal has a low Temperatur¬ drift on.

By the provisions recited in the dependent claims, advantageous refinements and improvements of the main claim are possible.

drawing

Exemplary embodiments of the invention are illustrated in the drawing and explained in more detail in the following description. In the drawings Figures 1 to 3 each show a longitudinal section through a modification of a measuring device.

Description of Embodiments

In Figure 1, a measuring device is designated 10, having a holder 11 with a cylindrical core 12 made of ferromagnetic material and a sleeve 13 of non-ferromagnetic but electrically conductive material. The axes of the core 12 and the sleeve 13 parallel to each other. At a second holder 15 serving as a second bobbin sleeve 16 and a cylindrical, mounted as bobbin serving second core 17th The sleeve 16 and the core 17 are preferably made of non-electrically conductive material. The axes of the core 17 and the sleeve 13 and the core 12 and the sleeve 16 are formed respectively on the same axis, so that in each case the core 12 can dip into the sleeve 16 and the core 17 in the sleeve. 13 On the core 17 or on the outer wall of the sleeve 16 is a respective current-carrying coil 19 of a Wechsel¬ arranged 20th , Is in the figure 1, only indicated, a measurement object 21 is fixed, which is to be determined Bewe¬ supply to the holder. 11 The holder 15 is then fixedly arranged. However, it is possible object, a reverse mounting of the Me߬, that is the measuring object is disposed on the holder 15 and the holder 11 is fixed. Further, a measurement object, but can also be secured to each holder 11 or 15, so that the two holders 11, 15 move relative to each and the difference between the two movements is determined.

The coils for. B. tet in a Wheatstone bridge according to Figure 4a or 4b, or in a non-illustrated Spaunngsteiler verschal¬, and flows through the coil 20, an alternating current, the alternating magnetic field of the coil 20 detects the inner surface of the sleeve 13. In a non-ferromagnetic, but electrically conductive material only the eddy current effect. Due to the surface on the Oberflä¬ the inner wall of the sleeve 13 forming eddy currents results in a reduction in the inductance of the coil 20 so that the level of the applied measurement voltage is decreased. The farther it penetrates the core 17 with the coil 20 in the sleeve 13, the greater the eddy current is training. Considering the coil 19, the magne¬ diagram alternating field of 12 by an alternating current-carrying Spu¬ le 19, the surface of the existing ferromagnetic material core with detected ferromagnetic effect is that in the coil 19 resulting with increasing penetration depth of the core 12 described Induk¬ tivitätserhöhung the coil 19, established by the ferromagnetic nature of the core material. In ferro¬ magnetic material, both the ferromagnetic effect and the eddy current effect is. While, as stated above, the eddy current effect causes a reduction in the inductance of the coil, the ferromagnetic effect causes an increase in the inductance of the coil. Therefore, the parameters (eg. B. Identification of characteristics of the core 12, the height of the frequency of the Wechsel¬ current to the coil 19 flows through) may be tuned so that the ferromagnetic effect predominates. The change in the inductance of the coil 19 is thus again a measure of the relative movement of the core 12 opposite the coil 19. When measuring the core 12 and the sleeve exert 13 at the same time the same movement, so that the inductance of the two coils 19, 20 oppositely changed, that is, the inductance of the coil 20 is decreased while the inductance of the coil is increased 19th Both coils 19, 20 may be in the 4a shown in FIG so-called "half bridge circuit" as each other are interconnected, that many measurement errors are compensated entirely or partially, during the measuring effect is additive. Further, one obtains a high yield in the signal ferromagnetic effect when the core is immersed in the coil 19 12th It has been shown that as high a measurement signal is achieved in the ferromagnetic effect if the coil were immersed in a sleeve of ferromagnetic material 19th When eddy current effect two variants are possible. It may penetrate both the core in a coil, and the coil in a sleeve.

In the embodiment according to FIG 2, the coil is arranged on a substantially centrally mounted on the holder 11a core 25 20a. The core 25 is covered by a sleeve 26 on which the coil is 19a. Between the sleeve 26 and the core 25, a ring 27 is arranged in the holder 11a. Between the sleeve 26 and the core 25 a fixed to the holder 15a sleeve 28 is movable. The sleeve 28 has an outer portion 29 made of ferromagnetic material and an inner portion 30 of non-ferromagnetic but electrically leit¬ enabled material. The sleeve 28, the sleeve 26 and the core 25 are formed coaxially. The operation of the Ausbildungs¬ example of Figure 2 is consistent with the Figure 1 after the match. but is particularly advantageous for the smaller size in a radial direction, and the central arrangement of the components.

In the embodiment, the measuring device 11c according to the figure 3, the bobbin for the coil 19b and 20b than in the support 15b attached sleeves 35, 36 are formed. Both sleeves 35, 36 are coaxial, the sleeve 35 surrounds the sleeve 36th The distance between the two sleeves 35, 36 is to make such that the magnetic fields of the coils a relatively minor influence in relation to the measuring effect against each other. In the sleeve 36, a core 37 projects out of a ferromagnetic material. Further, engages over the sleeve 35 is a sleeve 38 of non-ferromagnetic but electrically conductive material. The sleeve 38 and the core 37 are secured in the holder 11b by means of the ring 27b, and are coaxially to the sleeves 35, arranged 36th In principle it would also be possible in this formation Aus¬, the core 37 of non-ferromagnetic but Electrically conductive material and manufacture the sleeve 38 of ferromagnetic material. In this design, but the device under test would not plunge of ferromagnetic material into the coil.

In all embodiments it is possible, instead of the sleeves 13, 28, 38 or the nuts 12, 37 from the corresponding material on the sleeves, or at "~ the cores a layer of the appropriate material aufzubrir _;, -_ n Especially when.. exemplary embodiment according to FIG 2 may perform this procedure in a further reduction of the Bau¬ size in the radial direction. When the coil 20a, as mentioned above, by flowing an alternating current at a high enough frequency, it is possible on the inner part 30 of the sleeve 28 a be applied layer of non-ferromagnetic but electrically conductive material. Here, the various Aufbringungs¬, techniques such as adhesive bonding, plating, vapor deposition, etc. are ange¬ applies.

The evaluation of the inductance can be anticipated in different ways. The following are some examples:

The evaluation of the inductance of the two coils 19 and 20 can thereby be executed in the embodiment shown in Figure 4a "39/2 bridge circuit". The two coils 19, 20 are in a Wheatstone "half bridge circuit", that is, in a bridge with two "active" bridge branches 19, 20 and the passive Brücken¬ branches 40, 41, interconnected. but it is also possible, as shown in Figure 4b instead of using a half-bridge, a Wheatstone "full bridge", for evaluation. The two requisite additional sensor coils should preferably identical for both to be formed in Figure 4a shown coils of the Wheatstone half bridge. The coils 19d and 20d are then,. B. axially parallel additionally arranged. Of course, the evaluation of the change of the respective coil AC resistance can be anticipated using the Wheatstone bridge circuit instead of the direct evaluation of Spuleninduktivitätswerte, as they are dependent on the size of the respective coil inductors. As a further variant, evaluation can attach a parallel capacitor to each sensor coil. In this case beste¬ the hen "active bridge branches" of parallel resonant circuits whose resistance to depend also on the respective Spulenwechselstromwiderstän-.

Another evaluation device 42 for determining the Induktivi¬ tatsanderung the coils 19, 20 is shown in FIG. 5 The two coils 19, 20 are in series with one or two Konden¬ capacitors 43 in a resonant circuit connected. Here, by measuring the natural vibration period of the LC resonant circuit (L = Induk¬ tivity of the coil C = capacitance of the capacitor), the Induktivi¬ tätsänderung of the coils 19, 20 evaluated. In Figure 5, the coils 19 and 20 are connected into the resonant circuit alternately with the aid of the switch 44 there. The change in the oscillation period of the respective resonant circuit is dependent on the change of the respective coil inductance. As a measuring effect while the different natural oscillation period of the oscillating circuits is then used.

Depending on the design of both linear and radial movements can be determined.

Claims

claims
1. measuring means (10) for detecting a displacement or a Dreh¬ angle, with at least one on a body (16, 17) angeord¬ Neten, through which an alternating current coil (19, 20) operatively connected to areas (13) of electrically conductive but not ferromagnetic material, and areas (12) are made of ferro¬ magnetic material, characterized in that each area (12, 13) at least one coil (19, 20) is associated, so that with the relative movement of the sections (12, 13) and the coils (19, 20) to each other at the same time an opposite change in the inductance of the coils (19, 20) is effected.
2. Measuring device according to claim 1, characterized in that the region (12) of ferromagnetic material in at least one coil (19) is immersed.
3. Measuring device according to claim 1 and / or 2, characterized gekennzeich¬ net, that the axes of the coils (19, 20) are arranged parallel to each other ver¬ continuously. (Figure 1)
4. Device according to one of claims 1 to 3, gekenn¬ characterized characterized in that the region (13) is non-ferromagnetic but electrically conductive material at least on the inner wall of a sleeve (13) and the associated coil (20) within the sleeve (13) is moved, and that the region of ferro¬ magnetic material (12) within the associated coil (19) is moved.
5. Device according to claim 1 and / or 2, characterized in that a sleeve (28), and on its inside (30) has a region of electrically conductive but non-ferromagnetic material on its outer side (29) has a portion made of ferromagnetic material, has and that a coil (20a) is immersed in the sleeve (28) and the other coil (19a) of the sleeve (28) engages. (Figure 2)
6. The device according to claim 1 and / or 2, characterized in that the two coils (19b, 20b) separated on a per hülsenfÖr, achs¬ same bobbin (35, 36) are arranged such that a portion (37) of ferromagnetic material projects into the sleeve (36) and that a region of electrically conductive, non-ferromagnetic material as a sleeve-shaped body (38), the coils (19b, 20b) engages. (Figure 3)
7. Device according to one of claims 1 to 6, characterized gekenn¬ characterized in that the coils (19, 20) in a Wheatstone bridge circuit or voltage divider circuit (39) are interconnected.
8. Device according to one of claims 1 to 6, characterized gekenn¬ characterized in that the coils (19, 20) serially in a least one capacitor (43) having Resonanzsehwingkreis (42) are connected.
PCT/DE1990/000609 1989-09-07 1990-08-07 Measuring device for travel or angle of rotation WO1991003709A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DEP3929681.4 1989-09-07
DE19893929681 DE3929681A1 (en) 1989-09-07 1989-09-07 Measuring device for detection of a consistently or a rotating angle

Publications (1)

Publication Number Publication Date
WO1991003709A1 true WO1991003709A1 (en) 1991-03-21

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ID=6388790

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1990/000609 WO1991003709A1 (en) 1989-09-07 1990-08-07 Measuring device for travel or angle of rotation

Country Status (5)

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EP (1) EP0490904A1 (en)
CS (1) CS429890A3 (en)
DE (1) DE3929681A1 (en)
WO (1) WO1991003709A1 (en)
YU (1) YU158090A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10039619B4 (en) * 1999-09-27 2004-07-01 Detra S.A. Inductive proximity sensor with resonant circuit

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4120643B4 (en) * 1991-06-22 2004-04-08 Zf Sachs Ag Friction clutch with displacement sensor
RU2127865C1 (en) * 1997-07-24 1999-03-20 Медников Феликс Матвеевич Gear measuring linear translations ( versions )
DE19804414C2 (en) * 1998-02-05 2000-08-24 Micro Epsilon Messtechnik Inductive displacement sensor
DE19806529C2 (en) * 1998-02-17 2002-04-18 Micro Epsilon Messtechnik Off-angle sensor
JP2001074006A (en) * 1999-09-03 2001-03-23 Amitec:Kk Stroke sensor
DE10047939C2 (en) * 2000-09-27 2003-04-30 Vogt Electronic Ag Inductive displacement sensor
DE102005018797A1 (en) * 2005-04-22 2006-10-26 Bosch Rexroth Ag Displacement sensor and valve

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3891918A (en) * 1971-03-23 1975-06-24 James F Ellis Linear displacement transducer utilizing an oscillator whose average period varies as a linear function of the displacement
US4091234A (en) * 1977-03-30 1978-05-23 Atari, Inc. Joystick with attached circuit elements
GB2031587A (en) * 1978-08-05 1980-04-23 Nippon Denso Co Displacement sensor
DE3514154A1 (en) * 1985-04-19 1986-10-23 Bosch Gmbh Robert Beruehrungsfreies measurement procedure

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3891918A (en) * 1971-03-23 1975-06-24 James F Ellis Linear displacement transducer utilizing an oscillator whose average period varies as a linear function of the displacement
US4091234A (en) * 1977-03-30 1978-05-23 Atari, Inc. Joystick with attached circuit elements
GB2031587A (en) * 1978-08-05 1980-04-23 Nippon Denso Co Displacement sensor
DE3514154A1 (en) * 1985-04-19 1986-10-23 Bosch Gmbh Robert Beruehrungsfreies measurement procedure

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10039619B4 (en) * 1999-09-27 2004-07-01 Detra S.A. Inductive proximity sensor with resonant circuit

Also Published As

Publication number Publication date
YU158090A (en) 1994-01-20
DE3929681A1 (en) 1991-03-14
EP0490904A1 (en) 1992-06-24
CS429890A3 (en) 1992-06-17

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