WO2009095326A1 - Capteur de force - Google Patents

Capteur de force Download PDF

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Publication number
WO2009095326A1
WO2009095326A1 PCT/EP2009/050530 EP2009050530W WO2009095326A1 WO 2009095326 A1 WO2009095326 A1 WO 2009095326A1 EP 2009050530 W EP2009050530 W EP 2009050530W WO 2009095326 A1 WO2009095326 A1 WO 2009095326A1
Authority
WO
WIPO (PCT)
Prior art keywords
bending plate
force sensor
force
sensor according
particular according
Prior art date
Application number
PCT/EP2009/050530
Other languages
German (de)
English (en)
Inventor
Norbert Koczwara
Original Assignee
Werner Turck Gmbh & Co. Kg
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
Application filed by Werner Turck Gmbh & Co. Kg filed Critical Werner Turck Gmbh & Co. Kg
Publication of WO2009095326A1 publication Critical patent/WO2009095326A1/fr

Links

Classifications

    • 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
    • G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
    • G01L1/142—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors
    • 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
    • G01L1/18—Measuring force or stress, in general using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
    • 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
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G01L1/2206—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
    • 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
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G01L1/2206—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
    • G01L1/2231—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports the supports being disc- or ring-shaped, adapted for measuring a force along a single direction

Definitions

  • the invention relates to a force sensor with a housing which has on two facing away from each other housing sides force introduction sections.
  • Force sensors are needed in particular in medical technology.
  • the piston In the case of dosing syringes, the piston is continuously displaced by a slowly running engine into the cylinder in order to release the liquid in the cylinder in metered quantities.
  • a force sensor should be arranged between the piston and the piston drive. Force sensors are also used for pressure monitors.
  • pressure sensors In the prior art pressure sensors are known. These pressure sensors have a monolithic ceramic body with cup-shaped design. The pot bottom forms a bending plate, which bends depending on the applied pressure. A piezoelectric bottom is shown in US 4,594,898.
  • the invention is based on the object of specifying a simply constructed force sensor.
  • each claim represents an independent solution to the problem.
  • a force sensor with a flexurally elastic bending plate is provided.
  • This bending plate is connected to at least one edge portion fixed to a housing part of the force sensor.
  • the bending plate can be bar-shaped or circular disc-shaped. It can be fully connected with its edge with the housing part. However, it can also be connected to the housing part only with one or two opposite edges. be his.
  • the following features are optional developments of the invention. If necessary, with the interposition of a plastic disc, a force introduction member acts on the center or another section of the bending plate. The force introduction member acts with a curved surface on the bending plate. Depending on the applied pressure, the bending plate bends through. Means are provided to measure the deflection of the bending plate.
  • These means may be piezoresistive resistors which are arranged at different locations on the force introduction side facing away from the bending plate. Equally large or different sized fields can be applied by screen printing. These can be interconnected electrically in the form of a bridge circuit. The resistances of these fields applied to the surface of the bending plate change depending on the bend. It is further provided to measure the deflection by means of strain gauges.
  • the bending plate may also have a metal coating. This metal coating may form a capacitor with a second metal layer. With a deflection of the bending plate, the distance between the two metal layers changes, so that the capacitance of this capacitor changes. It is also possible to optically measure the deflection by reflection.
  • the force introduction element is in the simplest case a ball.
  • the opposite portion of the ball protrudes through an opening of a housing cover and forms a force introduction zone.
  • the bending plate may be part of a ceramic body.
  • the ceramic body has a pot shape.
  • the bending plate forms the bottom of the pot and is firmly connected to the cylinder section of the ceramic body.
  • This may be a monolithic ceramic body, in particular an AbO3 body.
  • a plastic disc lies between the force introduction surface of the ball and bending plate, a plastic disc.
  • the plastic disc is more flexible than the bending plate.
  • a circuit can be arranged, which converts the values supplied by the piezoresistive sensors.
  • the plastic disc is not necessary if the force introduction member with a curved surface directly applied to the center of the bending plate.
  • the corresponding section of the force introduction member may be made soft. But it can also have a slightly curved surface whose curvature contour corresponds to the bending contour of the maximum bent bending plate. As a result, the force application zone conforms to the contour line of the bent-through bending plate and thus increases the contact surface with increasingly introduced force and thus keeps the surface pressure at a low level.
  • the force introduction member may be a stamp or a steel ball.
  • the bending plate can be a round disc. It is then preferably connected with its entire edge with the surrounding housing part. This compound can be of the same material.
  • the bending plate is a bending beam. This is preferably firmly connected to the housing only with two opposite ends.
  • the bending beam preferably has a substantially rectangular outline contour, so that two opposite sides of the rectangle, which in particular are the narrow sides, are connected to the housing part. The two of these connecting points interconnecting rectangular sides are not connected to the housing part, so that the bending beam can bend freely.
  • the bending beam may be formed from the bottom of a cup-shaped opening. The two free marginal edges of the bending beam can be formed by a free cut.
  • the free cut is preferably formed by two mutually parallel slots.
  • the bending beam is connected in a planar manner to a circuit board which also carries other electronic circuit elements.
  • the sensors to the deflection of the bending beam too can be arranged on the board, which bends with the bending beam.
  • strain gauges are provided as measuring organs.
  • Fig. 1 in cross section a first embodiment
  • Figure 2 is a section along the line II - II in Figure 1.
  • FIG. 3 is an illustration according to FIG. 1 of a second embodiment
  • FIG. 4 shows an illustration according to FIG. 1 of a third exemplary embodiment
  • FIG. 5 shows a fourth embodiment of the invention in a representation according to FIG. 3;
  • FIG. 6 is a bottom view according to arrow VI in Fig. 5 and
  • FIG. 7 is a plan view according to arrow VII in Fig. 5th
  • a ceramic body 3 In the embodiment shown in Figure 1 sitting within a plastic or other suitable material existing housing 1, a ceramic body 3.
  • the ceramic body 3 is made of alumina and has a cup shape.
  • the outer bottom of the ceramic body 3 sits on a circumferential step of the housing 1 such that the thin-walled bottom of the pot can bend.
  • Within the cavity of the monolithic crystalline ceramic body 3 is a plastic disc 8, which extends over the entire cylindrical bending surface of a 5 forming bottom surface of the ceramic mik stresses 3 extends.
  • the center of the plastic disc 8, which is flexurally softer than the bending plate 5, is acted upon by a curved surface 7.
  • the force introduction member 6 is a ball.
  • the plastic disk 8 may also be smaller than the bending plate 5.
  • the plastic disk 8 then has a smaller diameter than the diameter of the diaphragm 5. In the edge region, the plastic disk 8 may also have a phase.
  • the housing 1 is provided with a lid 2, which has an opening 9 in the center. A coupling surface of the steel ball 6 protrudes through this opening. The section projecting through the opening 9 forms a force introduction section 10.
  • an electronic circuit 12 is arranged on a circuit board. This is electrically connected to a resistor arrangement on the outer side of the bending plate 5.
  • a total of four resistance surfaces 13 are printed on the outer side of the bending plate 5.
  • the resistive surfaces 13 are made of a material which is applied in a pasty state. The material solidifies and has a piezoresistive property when solidified. The thus manufactured resistors 13 change their resistance when the bending plate 5 bends. By a suitable wiring, such as bridge circuit, the resistance change, according to the Bend occurs, be measured. Temperature influences can be compensated.
  • the force introduction member is designed differently.
  • a punch 14 which extends substantially over the entire cross section of the cavity of the ceramic body 3. It has a flat curved contact surface 7, with which the punch 14 rests directly on the inside of the bending plate 5.
  • the curvature of the surface 7 is adapted to the curvature cross-sectional contour of the bending plate 5, if this is maximum curved. This creates a minimized surface pressure during the application of force.
  • the bending plate 5 is additionally coated with a conductive layer 15. This is a metal layer.
  • One of the bending plate 5 spaced surface, in the embodiment, the bottom surface of the housing 1 is also coated with metal.
  • This metal layer 16 running parallel to the coating 15 together with the layer 15 forms a plate capacitor. If the bending plate 5 bends, the capacitance of the plate capacitor changes. The capacity change can be measured in a known manner, for example by means of a resonant circuit.
  • an overload protection is additionally provided.
  • the ceramic body 3 is not supported on a circumferential edge of the housing 1, but on spring elements 17 at the bottom of the housing. If a force is now applied to the ball apex 11 of the force introduction member 6, not only does the bending plate 5 deflect. Rather, the spring elements 17 are also compressed, which is accompanied by removal of the ceramic body 3 from the opening 9. The ball 10 thus immersed not only due to the deflection of the bending plate 5 deeper into the opening 9, but also due to the evasive movement of the entire ceramic body 3 against the spring elements 17. This takes place until the apex of the ball 6 rests flush in the opening 9 , If then higher forces are exerted on the sensor, they are introduced directly into the housing 1, so that the maximum stress of the bending plate 5 is limited.
  • the bending plate 5 unlike the exemplary embodiments described above, is not circular in shape and is connected to the cylindrical body 4 with its entire circular edge.
  • the bending plate 5 is rather formed by a bending beam.
  • the housing part 4, which forms the cavity in which the punch 14 is arranged is rectangular in shape.
  • the bottom of this cavity is also formed here by the bending plate 5.
  • the bending plate 5 has a substantially rectangular cross-section.
  • the two opposite narrow sides 5 1 of the bending plate 5 are fixedly connected to the housing part 4.
  • the rectangular sides 5 "of the bending plate 5 extending transversely thereto are not connected to the housing part 4.
  • These free edges 5" of the bending plate 5 are formed by free cuts 18.
  • the material of the housing 4 and the material of the unit connected to the housing 4 bending plate 5 consists of a ceramic hybrid.
  • the free cuts 18, which extend over substantially the entire longitudinal extension of the bottom of the cavity of the housing 4, are preferably made after the finished case 4 has been formed by the sealing layer hybrids. This can be done by cutting eg. With a laser beam.
  • the ceramic housing 4 is embedded in a plastic housing 1, which also forms the cover 2.
  • the cover 2 also has an opening 9 through which the force introduction member 10 protrudes, which is firmly connected to the punch 14.
  • the bending body 5 and the cavity forming housing 4 forming ceramic body is glued onto a board 19 such that the deflection of the bending beam 5 leads to a partial deflection of the board 19.
  • the outwardly facing surface of the bending beam 5 is connected flat to the top of the board 19.
  • the board 19 also has free cuts, which are located at the location of the free cuts 18 and are slightly larger.
  • the board 19 On the side facing away from the bending beam 5, the board 19 carries a DMS bridge. This is arranged between the two slots and able to convert the deflection of the board 19 into electrical values. To evaluate these electrical values is a circuit 20, which is also arranged on the board.
  • the exemplary embodiment illustrated in FIGS. 5 to 7 is also a force sensor used in monitoring an automatic infusion device. For example, syringes are powered by a motor to inject a drug at constant flow over a long period of time. There may be, inter alia, two different disorders: The pressure in the tube on the way to the infusion needle decreases because, for example, the supply is used up, or the pressure increases because, for example, there is a blockage or the tube is kinked. Both incidents can be monitored by means of one of the previously described arrangements. Monitoring takes place by guiding the hose to the injection needle through a monitoring unit.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

L'invention concerne un capteur de force avec un boîtier qui présente des parties d’introduction de forces sur deux côtés de boîtier mutuellement opposés. Le capteur de force selon l’invention comprend : une plaque de flexion (5) en forme de disque circulaire, élastique en flexion, qui est fixement assemblée par un bord à une partie de boîtier (4) du capteur de force ; un organe d’introduction de forces (6) agissant perpendiculairement à l’extension de surface de la plaque de flexion (5) ; et des moyens (13, 15, 16) pour mesurer le fléchissement de la plaque de flexion (5).
PCT/EP2009/050530 2008-01-29 2009-01-19 Capteur de force WO2009095326A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE102008006475 2008-01-29
DE102008006475.0 2008-01-29
DE102008037572.1 2008-11-21
DE102008037572A DE102008037572A1 (de) 2008-01-29 2008-11-21 Kraftsensor

Publications (1)

Publication Number Publication Date
WO2009095326A1 true WO2009095326A1 (fr) 2009-08-06

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ID=40822273

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2009/050530 WO2009095326A1 (fr) 2008-01-29 2009-01-19 Capteur de force

Country Status (2)

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DE (1) DE102008037572A1 (fr)
WO (1) WO2009095326A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2713148A1 (fr) * 2012-09-27 2014-04-02 Honeywell International Inc. Capteur de force couplée mécaniquement sur une structure d'ensemble de plateforme flexible
DE102017121347A1 (de) 2017-09-14 2019-03-14 Turck Holding Gmbh Schlauchdrucksensor für eine Schlauchpumpenanordnung
CN113677973A (zh) * 2019-03-26 2021-11-19 采埃孚股份公司 用于制造传感器装置的方法及具有这种传感器装置的构件和/或底盘构件
WO2022168469A1 (fr) * 2021-02-02 2022-08-11 アルプスアルパイン株式会社 Capteur de charge

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9869598B1 (en) * 2016-06-24 2018-01-16 Honeywell International Inc. Low cost small force sensor

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4454771A (en) * 1980-11-07 1984-06-19 Hitachi, Ltd. Load cell
DE4103856A1 (de) * 1991-02-08 1992-08-13 Pfister Messtechnik Kraft- bzw. druckmessvorrichtung und herstellungsverfahren dafuer
US5760313A (en) * 1997-03-05 1998-06-02 Honeywell Inc. Force sensor with multiple piece actuation system
US6491647B1 (en) * 1998-09-23 2002-12-10 Active Signal Technologies, Inc. Physiological sensing device
US20040083825A1 (en) * 2002-11-05 2004-05-06 Tanita Corporation Diaphragm type load detection sensor, load detection unit and electronic scale using same
US20040181312A1 (en) * 2003-03-13 2004-09-16 Akito Miura Robot apparatus and load sensor
US7082844B1 (en) * 2005-02-16 2006-08-01 Cts Corporation Strain sensor having improved accuracy
US20070251328A1 (en) * 2006-04-26 2007-11-01 Honeywell International Inc. Force sensor package and method of forming same

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2141231B (en) 1983-06-07 1986-08-06 Gen Electric Co Plc Force sensors

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4454771A (en) * 1980-11-07 1984-06-19 Hitachi, Ltd. Load cell
DE4103856A1 (de) * 1991-02-08 1992-08-13 Pfister Messtechnik Kraft- bzw. druckmessvorrichtung und herstellungsverfahren dafuer
US5760313A (en) * 1997-03-05 1998-06-02 Honeywell Inc. Force sensor with multiple piece actuation system
US6491647B1 (en) * 1998-09-23 2002-12-10 Active Signal Technologies, Inc. Physiological sensing device
US20040083825A1 (en) * 2002-11-05 2004-05-06 Tanita Corporation Diaphragm type load detection sensor, load detection unit and electronic scale using same
US20040181312A1 (en) * 2003-03-13 2004-09-16 Akito Miura Robot apparatus and load sensor
US7082844B1 (en) * 2005-02-16 2006-08-01 Cts Corporation Strain sensor having improved accuracy
US20070251328A1 (en) * 2006-04-26 2007-11-01 Honeywell International Inc. Force sensor package and method of forming same

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2713148A1 (fr) * 2012-09-27 2014-04-02 Honeywell International Inc. Capteur de force couplée mécaniquement sur une structure d'ensemble de plateforme flexible
DE102017121347A1 (de) 2017-09-14 2019-03-14 Turck Holding Gmbh Schlauchdrucksensor für eine Schlauchpumpenanordnung
CN113677973A (zh) * 2019-03-26 2021-11-19 采埃孚股份公司 用于制造传感器装置的方法及具有这种传感器装置的构件和/或底盘构件
WO2022168469A1 (fr) * 2021-02-02 2022-08-11 アルプスアルパイン株式会社 Capteur de charge
JP7391251B2 (ja) 2021-02-02 2023-12-04 アルプスアルパイン株式会社 荷重センサ

Also Published As

Publication number Publication date
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