Kraftmessring mit einem ringförmigen gehäuse

5& 776 the invention concerns a force thimble with a circular housing, which takes up at least a piezoelectric measuring element, as well as with a pressure transmission element, which over inside and outside, circle-circular diaphragm ranges with the housing connected, preferably welded, ist.

The invention concerns further devices for the measurement from axial on a wave or a stamp working Kräften.

Force thimbles serve for the measurement of forces, pressures, accelerations and moments and become between power transmission means or machine parts eingespannt.

So is for example from the WHERE 2004/070334 AI a measuring sensor with initial tension device well-known, which essentially consists of an adapter part and an adapter case. The adapter part exhibits einstückig a central clamping sleeve, which rises up into a central drilling of the adapter case and can with a mother be linked up there. In a circular admission of the adapter case a force thimble is integrated, whereby the measuring elements of the force thimble in a circular housing are present and rest from one against the adapter part diaphragm are taken off. The diaphragm is under pre-loading by means of welding at the sensor housing befestigt.

The well-known force thimble in Fig becomes more detailed. described 1, for example in the special book (G. GAUTSCHI, “Piezoelectric of sensor” Springer publishing house 2002) it is represented to which. The force thimble 1 exhibits a circular housing 2, which one forms limited circular admission by an interior flange 8 and an external flange 9, to which two piezoelectric measuring elements 5 as well as a recording electrode 6 arranged between them is taken up. The recording electrode 6 leads to one at the external flange 9 fastened plug element 7. Kraft affecting the force thimble 1 becomes across the pressure transmission element 11 into the piezoelectric measuring elements 5 eingeleitet.

The pressure transmission element 11 exhibits an internal diaphragm range 12 as well as an outside diaphragm range 13, which with the interior flange 8 bzw.

the external flange 9 of the housing 2 are welded. Such force thimbles are suitable for measuring situations, with which Kraft which can be measured over the contact area of the pressure transmission element 11 one brings in evenly. There is this measuring situations, like it for example in WHERE the 2004/070334 AI quoted above stated sind.

However also applications exist, with which by a force application out vi even over the cross section of the pressure transmission elements 'cannot be gone. As example the axial force measurement of a ball bearing is in accordance with Fig. 2 mentioned. Must Kraft decreasing in one of the two ball cages werden.

Fig. a turning wave 20 with a load shows 2 in axial direction in the cross section, whereby the Wellenachse with 20 is characteristic '. The ball bearing 21 fastened on the turning wave exhibits an internal cage 22 and an outside cage 23, with which the camp balls 24 are led. During an introduction Kraft on the force thimble 1 is a circle-circular distance piece for even distribution Kraft on the force thimble 1 notwendig.

As unfavorable during this arrangement are on the one hand the large overall height as well as the higher elasticity of the measuring structure too nennen.

Task of the invention is it to improve a force thimble of the initially described kind in such a manner that the employment is satisfyingly possible also with asymmetrical force application and limited space conditions. In particular a robust is to be developed force thimble, with which axial forces, which affect a thrust ball bearing, are measured können.

This task is solved according to invention by the fact that the inside and the outside diaphragm range of the force thimble on opposite sides of one defined piezoelectric measuring element by that at least symmetry plane liegen.

In particular it is intended that the housing exhibits a first Gehäuseteil with a circular interior flange and a first pressure transmission element as well as a second Gehäuseteil with a circular external flange and a second pressure transmission element, whereby the internal diaphragm range between the interior flange and the second pressure transmission element and the outside diaphragm range between the external flange and the first pressure transmission element are arranged. From the execution according to invention of the force thimble a thimble with high rigidity and small elevator dimensions results, whereby without a distance piece to the strength-introductory surface, for example a thrust ball bearing, are done kann.

The invention becomes in the following on the basis of designs more near erläutert.

Show: Fig. 1 a force thimble in an axial section in accordance with state of the art, Fig. 2 the installation situation of a force thimble in accordance with state of the art for the measurement of axial forces those on a thrust ball bearing influences, Fig. 3 a sectional view of the force thimble in accordance with Fig. 2 in increased representation, Fig. 4 a force thimble according to invention in a sectional view in accordance with Fig. 5, an installation situation of the force thimble according to invention in a representation in accordance with Fig. 2, the Fig. 6 and 7 further execution variants of the force thimble according to invention in a sectional view in accordance with Fig.

1, as well as Fig. 8 a further installation situation of a force thimble according to invention in a Schnittdarstellung.

In Fig. 1 and 2 represented force thimble 1 including a bay situation in accordance with state of the art became already initially beschrieben.

The Fig. 3 and 4 shows the differences between the state of the art (Fig in a descriptive confrontation in increased yardstick. 3) and the invention (Fig. 4). With the force thimble 1 in accordance with state of the art in is the internal diaphragm range 12 and the outside diaphragm range 13 on a side of one by the piezoelectric measuring element 5 and/or the measuring element pile from two or several measuring elements 5 defined symmetry plane s angeordnet.

The pressure transmission element 11 is only connected thereby on both sides by the thin diaphragm ranges 12, 13 with the interior flange 8 and/or the external flange 9 of the housing 2. For an even force application from there a circular distance piece is 25 notwendig.

Different the situation is with the force thimble according to invention 1 in Fig. 4, its housing 2 a first, lower Gehäuseteil 3 with a circular interior flange 8 and a first pressure transmission element 10, as well as a second, upper Gehäuseteil 4 with a circular external flange 9 and a second pressure transmission element 11 exhibits. The internal diaphragm range 12 is arranged between the interior flange 8 and the second pressure transmission element 11. Further the outside diaphragm range 13 placed between the external flange 9 is and the first pressure transmission element 10. In contrast to the conditions thus internal 12 and the outside diaphragm range is to the technology the 13 on opposite sides of the symmetry plane defined by the piezoelectric measuring elements 5 e.

According to invention the interior flange can do 8 including the first pressure transmission element 10 and the outside diaphragm range 13 einstückig trained sein.

The same is valid for the external flange 9, the second pressure transmission element and the internal diaphragm range 12. Thus a robust force thimble, also during one-sided force application, develops like in Fig. 4 represented (S. of arrows 26) torsionally stiff is and without circular distance piece 25 auskommt.

Further the external flange can be strengthened implemented 9 in the comparison to the interior flange 8, around a further reinforcement of the force thimble to obtain with the represented example is welded the outside diaphragm range 13 at its outer edge with the external flange 9 and the internal diaphragm range 12 at its interior edge with the interior flange 8. The interior flange 8 and the first pressure transmission element 10 are essentially L-shaped trained in the cross section. The same is valid for the external flange 9 and the second pressure transmission element 11.

As is the case for the state of the art in accordance with Fig. 1 to 3 can do also with the force thimble according to invention in accordance with Fig. 4 to 7 for example two piezoelectric measuring elements 5 in the two-piece housing 2 arranged its, whose neighbouring contact areas contact a recording electrode 6. A plug element 7 (see Fig. 6 and 7) can do in the same way - as in Fig. 1 represented - at the external flange 9 arranged sein.

In Fig. 5 is the force thimble 1 in accordance with Fig. 4 in an installation situation for the measurement of the axial forces of a thrust ball bearing 21 represented. The intermediate ring 25 for the even introduction of the camp forces, necessary with well-known force thimbles, (see Fig. 2) can be void here, whereby the overall height of the measuring instrument is substantially reduced. The wave 20 supports itself, for example with a paragraph 26 of the wave 20, under span of a thrust ball bearing 21 at the force thimble 1 ab.

Into the Fig. 6 and 7 is variants of the force thimble according to invention 1 with different dimensions and remark details dargestellt.

In Fig. a further, favourable example of use of the invention is represented to 8. The stamp 27 on Kraft which can be measured concerns influences, intersperses the force thimble 1 here with its shank 28 a device for the measurement of one axially on a stamp 27 working Kraft using the force thimble according to invention 1., whereby the shank 28 rests against the circular interior flange 8 of the force thimble 1 and is centered by this. By the construction according to invention of the force thimble 1 it - in contrast to a force thimble in accordance with state of the art - comes to no relative motion between the shank 28 and the interior flange 8, whereby hysteresis features can be avoided during the power measurement. The force thimble 1 supports itself at an interior flange 29 of the housing 30 ab.

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