DD202758A1 - POWERS FOR DIRECT CONTACT FORCE MEASUREMENTS - Google Patents

Abstract

The invention relates to a force transducer for the direct measurement of contact forces on stationary or moving contacts in contact components, such as connectors, relays and switches. The aim and object of the invention is the development of an easily manageable, for direct and non-destructive measurement suitable force transducer, which allows to measure the normal force on original contact devices at the Kontaktberuehrungsstelle. The force transducer according to the invention consists of a magnetic circuit formed with a measuring tip adapted to the measuring object and provided with at least one active winding. The measuring tip has at least one gap, which is completely or partially filled in the deformation area with an elastic non-magnetic material. The gap is arranged so that the force acting changes the mean gap width, which can be evaluated by known electronic means. The force transducer is suitable for the solution of metrological tasks of the contact component industry, the precision mechanics and the Feingeraetebaus.

Description

231922 4

a) Title of the invention

Eraftaufnehmer for direct Eontaktkraftmessungen

H) Field of application of the invention

The invention relates to a force transducer for direct Eontaktkraftmessungen to stationary or moving electrical Eontakten, preferably such Eontakten that get into connectors, Eelais or switches are used, and serves the Eontrolle and safeguarding the quality of said components · The invention has great importance for contact development and Eontaktanwendung *

c) Characteristic of the known technical solutions

For the measurement of mechanical forces, a device is known from 2215232 which, for example, consists of a winding core and transverse bores for windings and which makes use of the magnetostriction.

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From the DD-PS 115 754- a device for measuring mechanical characteristics · νοη contact springs of electrical connectors is known, in which the DUT is held in a mechanical device and a mechanical force is applied by means of a contact gate.

The measurement of the Ytfeges takes place via a measuring microscope or profile projector ·

The Kachteile this device are in the awkwardness of the mechanics and the coupling to an optical measuring system as well as the limitation of the measuring possibility on individual contacts or contacts in cut insulators

Measurement of original components without destruction is rarely possible ·

The prior art also offers the possibility of the model (see Malucci, RP in Electrical Contacts 78, Chicago, September 11-15, 1978, pages 153-158). This publication describes the enlarged model of a slot clamp for developing development criteria · all acting on models and mechanical devices measuring arrangements have the disadvantage that a simple and non-destructive measurement on the finished device under real technological conditions is not possible ·

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d) Object of the invention

The aim of the invention is to provide a force transducer for direct contact force measurements, with the adhering to the prior art deficiency, such as-indirect measurement, high mechanical complexity and the much-needed destruction of the components are eliminated. In addition, the invention against the hitherto known with little time and ineßtechnischen effort measurements on a large scale slide to automatic series measurements using NC positioning allow.

e). Explanation of the 7th invention

- The technical task

The invention is the. Object to provide a force transducer for direct contact force measurements, which allows the normal force to original electrical or electronic components. nondestructive and direct to measure the contact contact parts, and which, the requirements of the DUT adapts and a signal that is in solid relation to the acting force emits.

Features of the invention

The object is achieved in that the developed for direct Kantaktkraftmessung mag-

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netic force transducer consists of a iait formed with a measured object MeBspitze formed magnetic circuit which is provided with at least one active winding, the probe tip has at least one gap which is arranged so that when force is applied to the Meßspitze the average gap width and thus the magnetic resistance changes ·

To increase the measurable Eraft can be introduced advantageously in the gap ein-suitable elastic werkstοϊΓ with non-magnetic properties · "The change in the magnetic resistance is meßteehnisch evaluated and until aux constants directly dependent on the Eraft.

The advantageous embodiment of the expiring to the measuring tip magnetic circuit allows the unproblematic measurement in narrow slots and üxinungen, as they are typical for Kontaktbauelemente · -

The measuring tip is adapted to the Meßerxoraernisaen in the outer geometric jporm · The signal processing is carried out exclusively, x ⁴ unischem way in a known manner, such as a bridge circuit ·

For temperature compensation, another unused force transducer can be thermally coupled to a first force transducer.

In order to compensate for geometrical dependencies of the Kraxtangrii-xspunktes and complicated elastic deformations, the acting gap is adaptive in terms of width and about the Meßeriordernissen so that deviations of Kraxi / vectors from the normal of the cleavage plane and a deviation of the gap surfaces of the plane itself apply · The geometry of the gap can be determined both computationally and empirically.

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For further compensations of magnetic linearities, known means, such as electronic measures and the use of calibration curves, are available.

A further advantageous embodiment of the invention is the constructive 'separability of the probe tip and magnetic circuit, so that a slight Meßspitzenwechsel is feasible;' In this case, the magnetic circuit can be constructed in several parts again.

The advantageous development of the force transducer, the disadvantages of the previously known measuring devices are eliminated and also created the ability to perform automatic series measurements.

f) embodiment

The invention will be explained below with reference to a drawing. ·

In the drawing represent:

Fig. 1: the load cell in the simplest design; Pig · 2 + 3: some variants of the Meßspitzengestaltung j Fig. 4-: the separate version of force transducer and Meßspitze »

The one in Pig. 1 comprises a magnetic circuit 2 provided with an active winding 3 serving for excitation, which terminates in a measuring tip 1 which has a rectangular cross-section. In the measuring tip 1, a gap 4- is present, which is filled with an elastic medium, such as rubber.

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The gap planes are parallel to each other and to the outer surfaces of the probe tip 1 », for example, has the dimensions of a contact pin. Using the relationships

N ^ Xr F

V ⁵ ° '^;

- and

m ^ / U ₀ A

results in the force to be measured

^ ^c

Simplified one can write:

= κ, η-K ₂

The symbols mean the following:

N number of turns of the winding 3

L inductance of the force transducer

R _1n J ₁ Q Magnetic resistance of the iron circle

c * 3 angular frequency of excitation voltage

u. AC

i alternating current.

A gap surface

/ U ₀ magnetic permeability of the gap

B_ magnetic resistance of the gap

c spring constant

σ gap width under force

5 * _ό gap width at F ^ O

X-inductive resistance

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It can be seen that the alternating current i "while maintaining the voltage u at the winding 5 of the force transducer is a measure of the force F and this strictly proportional, provided that working with small magnetic flux density, thus the value of the relative permeability of the iron circle and consequently the magnetic resistance Emire remains constant. Pig. 2a gives an example of the design of the split planes and Pig. 2b shows an example of the use of curved cleavage surfaces.

Ilg. 2e is an example of the design of the outer Kraltaufnehmergeometrie to reduce Nichtinearitäten by different points of application of force gezueseweise deformations ·

The geometries can be determined both mathematically and empirically.

FIG. 3 shows an embodiment of the measuring tip 12 with a double gap 4, which is applicable to cross-slotted sockets of connectors. FIG. 4 shows the possibility of the separate embodiment of the magnetic circuit 2 with winding 3 and the contact element 6 from the measuring tip 1 ·

Advantageously, an inelastic, non-magnetic isinlage ^ is introduced in the range aer x & nspannung to achieve a low-loss magnetic coupling of probe tip 1 and magnetic circuit 2.

This embodiment combines a favorable production of the magnetic circuit 2 with an easy exchange of Meßspi-uze i ·

Claims (1)

231922 4 Invention claims: Force transducer for direct Kontaktkraftmesaungen to stationary or moving contacts, preferably those that are used in connectors, relays and switches are used, wherein the change of the inductance is evaluated in a known manner, characterized in that the magnetic force transducer from a measured object adapted to the measuring tip C1) formed magnetic circuit C2), which is provided with at least one active winding (3), consists, and that the measuring tip (1) has at least one gap (4) which is arranged so that when force is applied to the measuring tip ( 1) the mean gap width and thus the magnetic 'resistance changes, wherein the gap (4) is adapted in width and shape to the Meßerfordernissen. Force transducer according to item 1, characterized in that the gap (4) to improve the elastic properties in the deformation region with an elastic non-magnetic material is completely or partially filled. 3. Force transducer according to item 1, characterized in that the force transducer also in several parts in the magnetic circuit C2) is extendable, wherein outside of the deformation regions an inelastic magnetic insert (5) is provided. For this 1 page. drawings η r η j λ -