CA1053028A - Magneto-elastic transducer - Google Patents
Magneto-elastic transducerInfo
- Publication number
- CA1053028A CA1053028A CA240,143A CA240143A CA1053028A CA 1053028 A CA1053028 A CA 1053028A CA 240143 A CA240143 A CA 240143A CA 1053028 A CA1053028 A CA 1053028A
- Authority
- CA
- Canada
- Prior art keywords
- core
- magneto
- transducer
- holder
- lugs
- 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
Links
- 230000004907 flux Effects 0.000 claims abstract description 14
- 239000000696 magnetic material Substances 0.000 claims abstract description 11
- 230000005291 magnetic effect Effects 0.000 claims abstract description 8
- 238000004804 winding Methods 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 7
- 238000003466 welding Methods 0.000 claims description 6
- 238000005259 measurement Methods 0.000 abstract description 3
- 230000004075 alteration Effects 0.000 abstract description 2
- 239000013013 elastic material Substances 0.000 abstract description 2
- 239000002184 metal Substances 0.000 description 5
- 230000001681 protective effect Effects 0.000 description 4
- BSYNRYMUTXBXSQ-UHFFFAOYSA-N Aspirin Chemical group CC(=O)OC1=CC=CC=C1C(O)=O BSYNRYMUTXBXSQ-UHFFFAOYSA-N 0.000 description 3
- 102000001324 CD59 Antigens Human genes 0.000 description 1
- 108010055167 CD59 Antigens Proteins 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 101710200331 Cytochrome b-245 chaperone 1 Proteins 0.000 description 1
- 102100037186 Cytochrome b-245 chaperone 1 Human genes 0.000 description 1
- 101710119396 Cytochrome b-245 chaperone 1 homolog Proteins 0.000 description 1
- 241001505295 Eros Species 0.000 description 1
- ULGZDMOVFRHVEP-RWJQBGPGSA-N Erythromycin Chemical compound O([C@@H]1[C@@H](C)C(=O)O[C@@H]([C@@]([C@H](O)[C@@H](C)C(=O)[C@H](C)C[C@@](C)(O)[C@H](O[C@H]2[C@@H]([C@H](C[C@@H](C)O2)N(C)C)O)[C@H]1C)(C)O)CC)[C@H]1C[C@@](C)(OC)[C@@H](O)[C@H](C)O1 ULGZDMOVFRHVEP-RWJQBGPGSA-N 0.000 description 1
- 101100345589 Mus musculus Mical1 gene Proteins 0.000 description 1
- 241001394244 Planea Species 0.000 description 1
- 238000004026 adhesive bonding Methods 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 239000005871 repellent Substances 0.000 description 1
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
- G01G19/08—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for incorporation in vehicles
- G01G19/12—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for incorporation in vehicles having electrical weight-sensitive devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
- G01B7/24—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in magnetic properties
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/12—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress
- G01L1/125—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress by using magnetostrictive means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/12—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress
- G01L1/127—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress by using inductive means
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
- Transducers For Ultrasonic Waves (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Abstract
Title of the Invention MAGNETO-ELASTIC TRANSDUCER
Abstract of the Disclosure A transducer for magneto-elastic stress measurement is formed of a holder and a core of magneto-elastic material provided with coils to generate a flux in and sense flux alterations produced by stresses of the core. The core is formed of one or more plates firmly attached to the holder and designed to be attached to the measuring object. The core may consist of a single plate attached to the holder at four symmetrical points, or of a cross having four arms the ends of which are welded to a frame of magnetic material which is secured to the holder. The holder may also be in the form of a casing of magnetic material which protects the core and coils and serves as a magnetic return path for the fluxes. For applica-tions where disturbing magnetic fields may occur in the measuring object, the casing is preferably made of non-magnetic material and provided with a frame of magnetic material as a return path for the flux.
Abstract of the Disclosure A transducer for magneto-elastic stress measurement is formed of a holder and a core of magneto-elastic material provided with coils to generate a flux in and sense flux alterations produced by stresses of the core. The core is formed of one or more plates firmly attached to the holder and designed to be attached to the measuring object. The core may consist of a single plate attached to the holder at four symmetrical points, or of a cross having four arms the ends of which are welded to a frame of magnetic material which is secured to the holder. The holder may also be in the form of a casing of magnetic material which protects the core and coils and serves as a magnetic return path for the fluxes. For applica-tions where disturbing magnetic fields may occur in the measuring object, the casing is preferably made of non-magnetic material and provided with a frame of magnetic material as a return path for the flux.
Description
BackFround of the Invention 1. Field of the Invention ~ he preDent invention relate~ to a transducer for ma~neto-ela~-tic stress meaaurement. ~he transducer i8 of the well known type having a core of magneto-elastic material provided with coils to ~enerate a mag-netic flux in the core and to sense the flux alterations which occur when the core i~ ~ub~ected to stres3 by a mech,~nical force.
Summary of the Invention According to the invention, the transducer has a holder to I which the core which is formed of at least one plate is ~irmly attached, and the holder can be attached to the measurin~ ob~ect. The core may be a 8illgl~ plate attached to the holder at four sJqm~etrically oppo~ite point~, or ma~ be a cross having four arms which are welded to a fr2me of magnetic material welded to the holder, 90 that the ~rame forms a return path for "
. . .
~5~'(J2B
the flux. The holder may also be in the form of a casing of magne-tic material arranged to protect the core and coils and -to serve as a magnetic return path for the flux. For applications where dlstur-bing magnetic fields may occur in the measuring object, the casing is preferably made of non-magnetic material and provided with a Exame of magnetic material as a return path for the ilux.
The transducer is primarily intended for use as A load indicator for trucks but can also be used in other fields. It is intended to be attached to the object to be measured for stress.
The transducer is preferably attached by means of welding, but ; other methods of attachment are also feasible, such as glueing.
Brief Description of the Drawings.
Preferred embodiments of the present invention will be hereafter described with reference to the accompanying drawings, wherein Figures la and lb show an embodiment of the transducer in which the core comprises a single, whole piece; `
Figures 2a and 2b show a cruciform core at-tached to a holder;
Figures 3a, 3b and 4 show one half of a dividable winding bobbin for a cruciform core;
Figures 5a, 5b and 5c show a transducer wherein both the coils and the core are made separately;
Figures 6a and 6b show a transducer in which both the core a~d -the holder are made from a single metal sheet;
i! Figures 7a' 7b and 7c show a transducer in which the holder is in the ~orm of a protective casing; figure 7a shows this transducer from below (with the bottom removed), figure 7b in sec-tion along the line A-A in figure 7a, and figure 7c from above;
Figure a shows a transducer substantially the same as that show in figures 7a-7c but designed for measuring the difference between two orthogonal stresses; and ~ - 2 -' ~(~S;~)Z8 Figures 9 and 10 show other embodiments wherein the mea-suring cross and the bobbin of the transducer are made as one unit.
Description oE the Preferred Embodiments ....__.A. ~. ~ __.. _ ... ~ ... __ ._ _... . . _ . _ The transducer according to Figs. la and lb comprises a holder 1 supporting the core 2 of the transducer with coils 3 and ~.
l'he holder is shown here as comprising four supports 5 held together by stays 6. The holder may be made in one piece or composed of the four suppor-ts and the four stays welded together, for instance.
The drawing is only an example of how the holder may be designed.
Many other embodiments are feasible. The important point is that the holder can easily be attached to a base, that the core is easily secured in the holder, preferably by means '' , . .
~` .
- 2a -' .
:
of weldin~, and that there is room for the ~,rindings. In the embodiment shown, the core consists of a single circwlar plate attached to the support 5 of the holder by ~relding at four point~ 7. 'rhe core has Iour holes 8 for the coils and the coils are arranged in two plane~ perpendi cular to each other and to the ~3urf`ace of the plate. 'rhe attachment points 7 lie syn~uetrically ln relation to the planea of the coils. One o' the windings is connected in a known manner to an alternatin~ voltaga uource 9 h~ving a suitable fre~guency and the other iB connocted to a mea-surin~ device 10.
Figures 2a and 2b show a s~Luare holder la, provided with four supports 5a. The core of the transducer i8 here in the form of a symme-trical cross with rour arm6 11 attached by their ends to the holder by means of welding~. ~he holder will therefore form a return path for the fluxes in the core. ~lowever, the return Or the fluxcs can be facilitated by welding a framè 1' of transformer plate to the holder either above or below the measuring cross.
Figure~ 3 and 4 show how the l,rindings are applied on the trans-ducer core according to ~igure 2a. A plate 12, shown in Figure 3, of in-sulating material has such outer contours that it can be placed inside the holder 1. It has four 810ts 13, open to the outside. One such plate i~ placed on each side o~ the cross and directed so that the 310ts are lo-cated o~er theopeningsbetween th~ arms 11 o~ the cross. The coils 3 and 4 are then wound on as shown in Fig~re 4, after which the end~ of the cros3 are secured to the holder.
It is important that the plates 12 and the coilæ 3, 4 applied thereon are either completel~sr free from the measuring cross 11 or are only in mechanical contact with the croæ~ at one ~rery limited point. qhis can be achieved by means of central elevation~ 26 on the plate~ 12, ~acing inwardly (Fig. 3 and Fig. 7b), which are preerably glued to the meagu~in~
cross at this point. mi8 ensures against any additional contact which could produce hysteresi3 and al~o facilitates the winding since the plate~
and the cro~s thus con~titute a coherent unit.
Figures 9 and 10 show other solution~ to the problem of hy~tP-~)S;~02~3 ~re~is-free bobbins. In both case~ the mea~uring cros~ and the bobbin are manufactured as one unit of magnetic plate either by stamping or l etching. Accordin~ to Fi~ure 9 the bobbin is composed OI four protru-sions ~0 from the central part 27 of the measurin~ cro~s, symmetrically placed between the cross arms 2~. q'he outer enas of the protrusion~
have preICerably ~-formed slota 31 for the windingl 3 and 4, According to Figure 10 the bobbin iB composed of four narrow, preferably U-formed ~tripu 32 which are completely free from the senling part of the cross and connected to the cros only at the four enlarged ends 29, which are to be firmly welded to the holder directly or via a ma~7netic return frame.
13oth types of combined measuring cross and bobbin have to be enameled except on the enlarged end ~urfaces to be welded to the holder.
Flgures 5a-5c show a transducer in which both tha coil~ and the core are made separately. The coils 3 and 4 are manufactured indi-vidually, one coil being given such dimensions that it can be fitted in-side the other. 'rhe winalng 3 is placed perpendicular to and in~ide the winding 4 as ~hown in Figures 5a and 5c. 'rwo ~trlps of mstal 14 and 15 are placed in a cros~ throu~h the windin~s as shown in Figure 5a. ~'he metal strips ~rith windlngs are attached in a llolder 1b of the type shown in Figure 5b by weldin~ the endæ of the strips 14, 15 to the ¢orner~ of ! . .
the holder by spot weld~ 169 as shown in Figure 5c '~he strips should be mechanically prestrassed when being attached.
~ he characteristic feature of the transducer according to the invention, that the core m~r con~ist of a single sheet of metal, enables the core and the holder to be m~nufactured ln one piece, ~tarting with a flat sheet as shown in Figures 6a and 6b. Four holes 20 are provided for the windines, placed symmetrically. A cross 18 is pressed from the flat sheet 17, raised above the flat surface to form an upper flat surface 19 at a certain level above the oriæinal flat ~urface of the plate and 80 ., that the holes 20 are located in the angles between -the four arms of the cross. This flalc surface 19 and the cross portion~ between the hole~ then provide the area where measurement is performed. ~he two holes for each coil are located opposite each other, which con~3iderably facllitate~ wind-lng. ; ' ' _4_ .' '' .
~alS30215 The transducer aceording to Figures 6a, 6b may also be manu-factured by punching the cro~s 18 ~epara-tely and welding it onto the flat plate 17. ~he coils can then be wound onto the cross 1fl before it is attaehed to the plate 17, Figures 7a-7e show a transdueer in which the holder 1e iB de-~igned aB a oup-shaped ¢asing, norm~lly of ma~netic material, protectin~
the eore 110 and windings 3, 4. ~he core 11c con~ists of a ~ingle plate in the form of a symmetrieal eros~ having four Brm8. On each side of the ~
oross is a plate 12 o Or in~ulating material, of substantially the same design as is shown in ~igure 3. ~he two inaulatin~ plates 12e form a bobbin for the windings 3 and 4. Figure 7b shows that the plates 12 are provided with a eentral elevation 26 80 that they are only in eontaet with the measuring orosc at one point. ~he ca~ing 1c is prov.ided with a ehoulder 21 to whieh the ends of'the measurine cross ~eore) 11c are welded and the ea~in~ th~s serves as a magneti¢ return path for the flux.
For applieations where disturbing magneti¢ field~ may oeeur in the mea-suring objeet, the easing is preferably made of non-maBnetie material ...
provided w1th a frame of magnetie material as a return path for the mag-netie flu~. The casing 1e-is provided with four lead-ins 22 for connec- ,:
tion leads to the windings 3, 4.
~ he easing 1e has two attachment lugs 23 plaeed diametrieally, eaeh provided with an elevation 24 on the lower ~ide, where the transdueer is intended to be seeured to the mPasuring ob~ec't, for example by spot welding. The eleYations 24 faeilitate attach~ent to the mea~uring.objeot .
. and also eliminate eontaet between the measurine ob~ect and other parts of the tran~dueer'whieh might eause hystere~iæ.
The transdueer easing 1e may suitably be surro~ulded by an outer proteetive eover (not shown). This protective eover ~hould be in direet eontaet with the transducer casing only at said elevations 23, whera the protective cover and the transducer casing are preferably wal-ded togetherO ~oth thermal and impact stre~ec are then taken up direetly by the measuring ob~eet and do not direetly affect the transdueer. Ihe ' spaee between the transducer easing and the protective eover may suitably , ~ , -be filled ~ith a water-repellent, thermally in~ulatine material h~ving little rigidity, in order to avoid undesired force tran~mission.
~ he tran~ducer casing i8 provided with a sealed bottom 25 which has ne~ligible force-tran~mitting ability. This bo-ttom may be made of rubber, for instanc~, in which case it i8 prefercibly attached to the trans-ducer cacing by ~lueing or vulcanizin~. It may also connict of a (pref-erably ¢orIugated) metal membrane. Another po~sibility is to use a metal bottom whioh iB elasticall~ joined to the tr,m sducer casing by mean~ of a rubber insert which i~ glued or vulcanized to the casing and the bottom.
~ he tran~ducer shown in Figuree 7a-7c is intended ~or measuring stres~ only in the pull-push direction indicated by the a~row ~ (Fig. 7c).
The embodiment shown in Figure 8 al~o permit~ measurement of the differ-ence between the stresse~ in t~o directions lying perpendicular to each other For this purpose the tran~ducer is provided with four attachment lug~ t but doe~ not otherwise differ from the embodiment shown in Fig-ures 7a-7c~
~, . ' ' - . ,,, :
- ' ~ , ,, ,., , : ' :'
Summary of the Invention According to the invention, the transducer has a holder to I which the core which is formed of at least one plate is ~irmly attached, and the holder can be attached to the measurin~ ob~ect. The core may be a 8illgl~ plate attached to the holder at four sJqm~etrically oppo~ite point~, or ma~ be a cross having four arms which are welded to a fr2me of magnetic material welded to the holder, 90 that the ~rame forms a return path for "
. . .
~5~'(J2B
the flux. The holder may also be in the form of a casing of magne-tic material arranged to protect the core and coils and -to serve as a magnetic return path for the flux. For applications where dlstur-bing magnetic fields may occur in the measuring object, the casing is preferably made of non-magnetic material and provided with a Exame of magnetic material as a return path for the ilux.
The transducer is primarily intended for use as A load indicator for trucks but can also be used in other fields. It is intended to be attached to the object to be measured for stress.
The transducer is preferably attached by means of welding, but ; other methods of attachment are also feasible, such as glueing.
Brief Description of the Drawings.
Preferred embodiments of the present invention will be hereafter described with reference to the accompanying drawings, wherein Figures la and lb show an embodiment of the transducer in which the core comprises a single, whole piece; `
Figures 2a and 2b show a cruciform core at-tached to a holder;
Figures 3a, 3b and 4 show one half of a dividable winding bobbin for a cruciform core;
Figures 5a, 5b and 5c show a transducer wherein both the coils and the core are made separately;
Figures 6a and 6b show a transducer in which both the core a~d -the holder are made from a single metal sheet;
i! Figures 7a' 7b and 7c show a transducer in which the holder is in the ~orm of a protective casing; figure 7a shows this transducer from below (with the bottom removed), figure 7b in sec-tion along the line A-A in figure 7a, and figure 7c from above;
Figure a shows a transducer substantially the same as that show in figures 7a-7c but designed for measuring the difference between two orthogonal stresses; and ~ - 2 -' ~(~S;~)Z8 Figures 9 and 10 show other embodiments wherein the mea-suring cross and the bobbin of the transducer are made as one unit.
Description oE the Preferred Embodiments ....__.A. ~. ~ __.. _ ... ~ ... __ ._ _... . . _ . _ The transducer according to Figs. la and lb comprises a holder 1 supporting the core 2 of the transducer with coils 3 and ~.
l'he holder is shown here as comprising four supports 5 held together by stays 6. The holder may be made in one piece or composed of the four suppor-ts and the four stays welded together, for instance.
The drawing is only an example of how the holder may be designed.
Many other embodiments are feasible. The important point is that the holder can easily be attached to a base, that the core is easily secured in the holder, preferably by means '' , . .
~` .
- 2a -' .
:
of weldin~, and that there is room for the ~,rindings. In the embodiment shown, the core consists of a single circwlar plate attached to the support 5 of the holder by ~relding at four point~ 7. 'rhe core has Iour holes 8 for the coils and the coils are arranged in two plane~ perpendi cular to each other and to the ~3urf`ace of the plate. 'rhe attachment points 7 lie syn~uetrically ln relation to the planea of the coils. One o' the windings is connected in a known manner to an alternatin~ voltaga uource 9 h~ving a suitable fre~guency and the other iB connocted to a mea-surin~ device 10.
Figures 2a and 2b show a s~Luare holder la, provided with four supports 5a. The core of the transducer i8 here in the form of a symme-trical cross with rour arm6 11 attached by their ends to the holder by means of welding~. ~he holder will therefore form a return path for the fluxes in the core. ~lowever, the return Or the fluxcs can be facilitated by welding a framè 1' of transformer plate to the holder either above or below the measuring cross.
Figure~ 3 and 4 show how the l,rindings are applied on the trans-ducer core according to ~igure 2a. A plate 12, shown in Figure 3, of in-sulating material has such outer contours that it can be placed inside the holder 1. It has four 810ts 13, open to the outside. One such plate i~ placed on each side o~ the cross and directed so that the 310ts are lo-cated o~er theopeningsbetween th~ arms 11 o~ the cross. The coils 3 and 4 are then wound on as shown in Fig~re 4, after which the end~ of the cros3 are secured to the holder.
It is important that the plates 12 and the coilæ 3, 4 applied thereon are either completel~sr free from the measuring cross 11 or are only in mechanical contact with the croæ~ at one ~rery limited point. qhis can be achieved by means of central elevation~ 26 on the plate~ 12, ~acing inwardly (Fig. 3 and Fig. 7b), which are preerably glued to the meagu~in~
cross at this point. mi8 ensures against any additional contact which could produce hysteresi3 and al~o facilitates the winding since the plate~
and the cro~s thus con~titute a coherent unit.
Figures 9 and 10 show other solution~ to the problem of hy~tP-~)S;~02~3 ~re~is-free bobbins. In both case~ the mea~uring cros~ and the bobbin are manufactured as one unit of magnetic plate either by stamping or l etching. Accordin~ to Fi~ure 9 the bobbin is composed OI four protru-sions ~0 from the central part 27 of the measurin~ cro~s, symmetrically placed between the cross arms 2~. q'he outer enas of the protrusion~
have preICerably ~-formed slota 31 for the windingl 3 and 4, According to Figure 10 the bobbin iB composed of four narrow, preferably U-formed ~tripu 32 which are completely free from the senling part of the cross and connected to the cros only at the four enlarged ends 29, which are to be firmly welded to the holder directly or via a ma~7netic return frame.
13oth types of combined measuring cross and bobbin have to be enameled except on the enlarged end ~urfaces to be welded to the holder.
Flgures 5a-5c show a transducer in which both tha coil~ and the core are made separately. The coils 3 and 4 are manufactured indi-vidually, one coil being given such dimensions that it can be fitted in-side the other. 'rhe winalng 3 is placed perpendicular to and in~ide the winding 4 as ~hown in Figures 5a and 5c. 'rwo ~trlps of mstal 14 and 15 are placed in a cros~ throu~h the windin~s as shown in Figure 5a. ~'he metal strips ~rith windlngs are attached in a llolder 1b of the type shown in Figure 5b by weldin~ the endæ of the strips 14, 15 to the ¢orner~ of ! . .
the holder by spot weld~ 169 as shown in Figure 5c '~he strips should be mechanically prestrassed when being attached.
~ he characteristic feature of the transducer according to the invention, that the core m~r con~ist of a single sheet of metal, enables the core and the holder to be m~nufactured ln one piece, ~tarting with a flat sheet as shown in Figures 6a and 6b. Four holes 20 are provided for the windines, placed symmetrically. A cross 18 is pressed from the flat sheet 17, raised above the flat surface to form an upper flat surface 19 at a certain level above the oriæinal flat ~urface of the plate and 80 ., that the holes 20 are located in the angles between -the four arms of the cross. This flalc surface 19 and the cross portion~ between the hole~ then provide the area where measurement is performed. ~he two holes for each coil are located opposite each other, which con~3iderably facllitate~ wind-lng. ; ' ' _4_ .' '' .
~alS30215 The transducer aceording to Figures 6a, 6b may also be manu-factured by punching the cro~s 18 ~epara-tely and welding it onto the flat plate 17. ~he coils can then be wound onto the cross 1fl before it is attaehed to the plate 17, Figures 7a-7e show a transdueer in which the holder 1e iB de-~igned aB a oup-shaped ¢asing, norm~lly of ma~netic material, protectin~
the eore 110 and windings 3, 4. ~he core 11c con~ists of a ~ingle plate in the form of a symmetrieal eros~ having four Brm8. On each side of the ~
oross is a plate 12 o Or in~ulating material, of substantially the same design as is shown in ~igure 3. ~he two inaulatin~ plates 12e form a bobbin for the windings 3 and 4. Figure 7b shows that the plates 12 are provided with a eentral elevation 26 80 that they are only in eontaet with the measuring orosc at one point. ~he ca~ing 1c is prov.ided with a ehoulder 21 to whieh the ends of'the measurine cross ~eore) 11c are welded and the ea~in~ th~s serves as a magneti¢ return path for the flux.
For applieations where disturbing magneti¢ field~ may oeeur in the mea-suring objeet, the easing is preferably made of non-maBnetie material ...
provided w1th a frame of magnetie material as a return path for the mag-netie flu~. The casing 1e-is provided with four lead-ins 22 for connec- ,:
tion leads to the windings 3, 4.
~ he easing 1e has two attachment lugs 23 plaeed diametrieally, eaeh provided with an elevation 24 on the lower ~ide, where the transdueer is intended to be seeured to the mPasuring ob~ec't, for example by spot welding. The eleYations 24 faeilitate attach~ent to the mea~uring.objeot .
. and also eliminate eontaet between the measurine ob~ect and other parts of the tran~dueer'whieh might eause hystere~iæ.
The transdueer easing 1e may suitably be surro~ulded by an outer proteetive eover (not shown). This protective eover ~hould be in direet eontaet with the transducer casing only at said elevations 23, whera the protective cover and the transducer casing are preferably wal-ded togetherO ~oth thermal and impact stre~ec are then taken up direetly by the measuring ob~eet and do not direetly affect the transdueer. Ihe ' spaee between the transducer easing and the protective eover may suitably , ~ , -be filled ~ith a water-repellent, thermally in~ulatine material h~ving little rigidity, in order to avoid undesired force tran~mission.
~ he tran~ducer casing i8 provided with a sealed bottom 25 which has ne~ligible force-tran~mitting ability. This bo-ttom may be made of rubber, for instanc~, in which case it i8 prefercibly attached to the trans-ducer cacing by ~lueing or vulcanizin~. It may also connict of a (pref-erably ¢orIugated) metal membrane. Another po~sibility is to use a metal bottom whioh iB elasticall~ joined to the tr,m sducer casing by mean~ of a rubber insert which i~ glued or vulcanized to the casing and the bottom.
~ he tran~ducer shown in Figuree 7a-7c is intended ~or measuring stres~ only in the pull-push direction indicated by the a~row ~ (Fig. 7c).
The embodiment shown in Figure 8 al~o permit~ measurement of the differ-ence between the stresse~ in t~o directions lying perpendicular to each other For this purpose the tran~ducer is provided with four attachment lug~ t but doe~ not otherwise differ from the embodiment shown in Fig-ures 7a-7c~
~, . ' ' - . ,,, :
- ' ~ , ,, ,., , : ' :'
Claims (8)
1. A magneto-elastic transducer for measuring strain in a mechanically loaded object, comprising:
a core of magneto-strictive material including windings for generating a magnetic flux in the core and for sensing the changes in the flux which occur when the core is affected by me-chanical forces, said core being made of a single plate in the form of a cross with four mutually perpendicular arms, said arms being joined together at one of their respective ends, the other ends being provided with enlarged end surfaces;
a cup-shaped casing including a shoulder for supporting said enlarged end surfaces, said end surfaces being fastened to the shoulder by welding, said cup-shaped casing being provided with at least one pair of force-transmitting lugs for fastening the transducer to the loaded object.
a core of magneto-strictive material including windings for generating a magnetic flux in the core and for sensing the changes in the flux which occur when the core is affected by me-chanical forces, said core being made of a single plate in the form of a cross with four mutually perpendicular arms, said arms being joined together at one of their respective ends, the other ends being provided with enlarged end surfaces;
a cup-shaped casing including a shoulder for supporting said enlarged end surfaces, said end surfaces being fastened to the shoulder by welding, said cup-shaped casing being provided with at least one pair of force-transmitting lugs for fastening the transducer to the loaded object.
2. A magneto-elastic transducer as in claim 1 wherein said windings are supported by a pair of insulating plates inclu-ding an elevated portion for supporting said insulating plates core in a point contact relationship with said core to reduce hysteresis.
3. A magneto-elastic transducer as in claim 1 wherein said force-transmitting lugs consist of two oppositely disposed lugs in line with one of the arms of said core.
4. A magneto-elastic transducer as in claim 3 wherein said lugs extend below the bottom of said cup-shaped casing to provide an elevated mounting of said transducer on the loaded object.
5. A magneto-elastic transducer as in claim 1 wherein said force-transmitting lugs consist of four symmetrically arran-ged lugs respectively aligned with the arms of said core.
6. A magneto-elastic transducer as in claim 1 wherein said casing is made of non-magnetic material and further compri-sing a frame of magnetic material to provide a return path for the magnetic flux.
7. A magneto-elastic transducer as in claim 1 wherein said cup-shaped casing is made of magnetic material to provide a return path for the flux.
8. A transducer according to claim 1, in which said cup-shaped casing further includes two pairs of force-transmitting lugs, said two pairs of lugs being arranged symmetrically in re-lation to each other.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7414683A SE386738B (en) | 1974-11-22 | 1974-11-22 | MAGNETOELASTIC SENSOR |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1053028A true CA1053028A (en) | 1979-04-24 |
Family
ID=20322787
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA240,143A Expired CA1053028A (en) | 1974-11-22 | 1975-11-20 | Magneto-elastic transducer |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5751613B2 (en) |
| CA (1) | CA1053028A (en) |
| DE (1) | DE2550288C3 (en) |
| FR (1) | FR2292212A1 (en) |
| GB (1) | GB1517758A (en) |
| IT (1) | IT1051267B (en) |
| SE (1) | SE386738B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4516116A (en) * | 1981-12-16 | 1985-05-07 | Safety Devices (Engineering) Limited | Apparatus for visually displaying the load-moment, axle-load, or payload of a vehicle |
| DE3429348A1 (en) * | 1984-08-09 | 1986-02-20 | Robert Bosch Gmbh, 7000 Stuttgart | Magnetoelastic dynamometer |
| JP3163965B2 (en) * | 1995-09-27 | 2001-05-08 | 三菱自動車工業株式会社 | Structure of magnetostrictive sensor |
| DE19637614A1 (en) * | 1996-09-16 | 1997-11-13 | Bosch Gmbh Robert | Compact sensor for registering tensile, compressive or shear forces |
| EP3745107B1 (en) * | 2019-05-27 | 2024-11-20 | Technische Hochschule Würzburg-Schweinfurt | Device and method for measuring mechanical stress based on magnetostriction |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE741021C (en) * | 1933-09-12 | 1943-11-03 | Siemens Ag | Arrangement for measuring mechanical forces |
| US2749746A (en) * | 1953-07-14 | 1956-06-12 | Gen Electric | Magnetostriction strain gauge |
| US3372580A (en) * | 1965-05-27 | 1968-03-12 | Robinson Halpern Company | Force transducer |
-
1974
- 1974-11-22 SE SE7414683A patent/SE386738B/en not_active IP Right Cessation
-
1975
- 1975-10-30 GB GB44927/75A patent/GB1517758A/en not_active Expired
- 1975-11-08 DE DE2550288A patent/DE2550288C3/en not_active Expired
- 1975-11-18 FR FR7535162A patent/FR2292212A1/en active Granted
- 1975-11-20 JP JP50138782A patent/JPS5751613B2/ja not_active Expired
- 1975-11-20 CA CA240,143A patent/CA1053028A/en not_active Expired
- 1975-11-21 IT IT69878/75A patent/IT1051267B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| IT1051267B (en) | 1981-04-21 |
| SE7414683L (en) | 1976-05-24 |
| DE2550288A1 (en) | 1976-05-26 |
| JPS5751613B2 (en) | 1982-11-02 |
| FR2292212A1 (en) | 1976-06-18 |
| JPS51102692A (en) | 1976-09-10 |
| FR2292212B1 (en) | 1979-03-16 |
| DE2550288C3 (en) | 1979-10-04 |
| SE386738B (en) | 1976-08-16 |
| GB1517758A (en) | 1978-07-12 |
| DE2550288B2 (en) | 1979-02-08 |
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