CS241773B1 - Strain gauge deformation member - Google Patents

Abstract

The strain gauge deformation element (11) for converting force or pressure acting in the direction (P) by means of a resistance strain gauge f7) into an output electrical signal consists of a pot-shaped body (1), in the bottom (5) and wall (9) of which a single- or multi-arm elastically deformable beam (16) with arms (23) supported by struts (14, 18) and a ring (8) of the base (2) is defined by curved gaps (25). A stop gap (22) can be made at the stop strut (18) to define the total deflection. The remaining parts of the bottom (3), or possibly also the walls (95), can be removed between the side walls (20) of the adjacent arms (23) by cutting off the wall (9) in a plane intersected by the upper surface of the ring (8).

Description

(54) Strain gauge

A strain gauge deformation member (11) for converting forces or pressures acting in the direction (P) by means of a resistance strain gauge f7) to an output electrical signal consists of a pot-shaped body (1), the bottom (5) and wall (9) of which a one- or multi-arm elastically deformable beam (16) is defined by gaps (25) with arms (23) supported by webs (14, 18) against a ring (8) of the base (2). A stop gap (22) can be provided for the stop bar (18). defining the total deflection. The remaining parts of the bottom (3) and possibly the wall (95) can be removed between the side walls (20) of the adjacent arms (23) by cutting off the wall (9) in a plane interlaced with the upper surface of the ring (8).

(11) Int., (51) Int. Clí

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The invention relates to a strain gauge strain member and solves the problem of an easy-to-use multipurpose deformation member for sensing tenths of the order of N to kN and pressures of the order of hundredths to tens of MPa at mechanical-electrical converters.

Crumple element with resistance strain gauges for measuring forces and pressures above values are usually designed as bending beams, and either <5 as ^the beams on two supports or clamped beams unilateral. When measuring the pressure, this deformation member senses the deformation of the diaphragm, bellows or pressure gauge box caused by the pressure. The basic disadvantage of the known deformation members is the relatively high cost of their production. Manufacturing requires a large proportion of expensive milling.

Sometimes cost savings are achieved by the deformation member being composed of a plurality of shaped parts, which are simple to manufacture. For example, German patent application DE-OS 22 37 353 describes a pressure sensor of essentially simple construction, composed of a plurality of parts connected by screw connections. Such savings in production costs, however, result in lower accuracy due to hysteresis in some screw connections *

These disadvantages are substantially eliminated by the strain gauge deformation member of the present invention. The object of the invention is that the defarmable beam and its at least one web are jointly defined in the bottom and in the wall of the pot-shaped body by at least two gaps, the base of the tensometric deformation member being formed by the open end of the pot-shaped body.

In alternate embodiments of the invention, in the case of a single-arm girder, the gaps in the bottom contact surface are guided parallel and symmetrically, and the bottom is divided by a further gap between the two previous gaps.

In alternatives, embodiments with a multi-armed beam are; one arm and its web in the bottom and in the wall of the pot-shaped body are defined by two curved gaps and the individual arms are arranged with respect to the axis of the pot-shaped body sy241773

- 2 metric, wherein the angle between two adjacent legs SEL '18Ο equals ^{0 or} is less than 180 °.

In other alternatives, the planes interspersed with the side walls of the deflectable beam intersect above the bottom surface of the pot body, the bottom surface is perpendicular to the axis of the pot body, the non-functional portions of the bottom and the walls of the pot body are removed. .

According to the latest alternatives of the invention, the pot body is rotatable, for example cylindrical in shape, and the deformable beam is weakened at the attachment point of the strain gauge.

The advantage of the strain gauge deformation member according to the invention is that the entire basic hollow pot can be made by pressing, extruding or turning instead of earlier milling, and by subsequently cutting its bottom and wall a considerable number of different types of deformable beam can be created .

1 shows a strain-gauge deformation member with a resilient deformable beam on two webs with the side part of the dysfunctional remainder of the bottom and the wall removed, FIG. 2 shows a deformable beam unilaterally fixed, FIG. Fig. 4 shows a three-arm deformable beam, Fig. 5 shows a four-arm beam with a stop gap at one web, and Figs. 6 to 16 in plan view of the bottom β with alternatives of different types of deformable beam.

The pot-shaped body 1 preferably has a rotationally cylindrical shape with an optionally widened ring 8 forming at the open end of the pot-shaped body X a base 10 of a strain-gauge deformation member 11 and with a base J whose bearing surface is perpendicular to its axis.

In the upper part of the pot of the body and of the smaller diameter, according to FIG. 1, two parallel gaps are symmetrical to its axis, in the bottom 1 a deformable beam 4 and in the wall 4 a pair of support legs 4. According to FIG. 3, a stop gap 12 may be provided in one of them, for example in the web 12, as desired. One lateral non-functional part of the remainder of the bottom 3 and the wall 5 is removed and the other side part is left for illustration. A resistive strain gauge 2 is attached to the deformable beam. At the attachment point of the strain gauges 2 ^{m, the} deformable beam 6 can be weakened by removing the annular groove 19 in the bearing surface of the bottom 2 or on the opposite side thereof.

FIG. 2 shows an alternative embodiment of a strain gauge deformation member 11 having an outer wall 6 of equal diameter with the base 6. In the bottom 10, another deformable beam 15 extending perpendicularly to the two previous parallel gaps 2 is formed as a deformable beam 6 as a one-sidedly fixed beam connected by a web 54 by a base 54.

Referring to FIG. 4, a multi-arm deformable beam 16 with three legs 13 is formed in the wall 6 of the tensometric deformation member 21 at the bottom Ja in the wall 6, supported on three webs protruding from the base 6. The arms 13 are connected to each other at the center of the base J and are arranged symmetrically. The arms 13 have side walls 20 forming half of the curved gap 25 made during production in the bottom J and in the wall 6. The resistance strain gauges 6 may be adhered to any arm 13. Alternatively, each arm 13 may be fitted with a separate measuring system of bridged resistance strain gauges 2. The arms 13 may: be weakened at the attachment point of the strain gauges 2 by forming an annular groove 19 in or opposite the inner side and / or removing the recesses in the side wall 20.

FIG. 5 shows a strain gauge deformation member 21 with a multi-arm deformable beam 16 with four symmetrically arranged arms 23. A stop gap 22 is provided in the stop web 18.

In the case of multi-leg deformable beams 16, the individual legs 13, 23 generally form the same angle with each other. Their arrangement may also be along the axis of symmetry, where the angle formed by the at least one pair of arms 13 is different from the others.

The planes intersected by the straight side walls 10 of the deformable beam 6 or the side walls 20 of the individual arms 13 may intersect each other above the contact surface of the base J.

If the side walls 20 are curved according to FIG. 16, their surface may be curved according to the cone or cylinder housing, whose axes intersect above the bearing surface of the bottom J the axis of the body 1.

The remaining non-functional portions of the bottom 3 and the walls inclined to the side walls 10, 20 can be removed by cutting along a plane intersected by the upper surface of the ring 8, or only remnants of the bottom J can be removed.

By application of the force P in the direction of the arrow, the deformable beam 6, 16 is bent to the limit defined by the doraa gap 12, 22, and a signal is sent from the resistance strain gauge 2 for further processing according to its character.

The main advantage of the solution of the strain gauge deformation member 11, 21 is the simplification of its production. The rotary cylindrical pot-shaped body 1 can preferably be produced on a lathe, and the various shapes of the deformable beam 6, 16 can be formed, for example, by cutting, which produces straight gaps 2 or straight sections of bent gaps 25.

The pot-like body 1 can also be formed, for example, by pressing or extrusion. This is particularly advantageous in the case SEU / ^L for volume production or if it is necessary to solve the production of a different ground plan shape of the bottom base and J £ than circular. It is also possible to create a gap 2, 15 and 35 other than by cutting, for example _; cutting by laser beam or plasma torch. That then; opens the possibilities of structural design of the deformable beam 6, 16 with arbitrary ground shape of the gaps 15, 15 β 2.5 ia and thus the choice of the type that best meets the requirements of the strain gauge deformation member 11, 21.

All of the gaps 15 and 25 used in the description of the invention are continuous, that is to say they have a distribution function in the bottom J and in the wall. If, in some alternatives, the remainder of the bottom 2 and the walls <> are removed, the gaps Σ, X5 and 25 will disappear, leaving only the side walls 10. 20. The planes interspersed with the side walls 10, 20 will then characterize the type of deformable beam 6, 16 as shown in more detail in FIGS. 6 to 16.

The strain-gauge deformation element according to the invention is particularly intended for meehano-electric transducers of force and pressure transducers for electronic systems for measuring, testing, controlling and regulating various processes, machines and equipment.

Claims (12)

SUBJECT OF THE INVENTION A strain-gauge deformation member consisting of a base and a protruding at least one web with a resiliently deformable beam and a resistance strain gauge mounted thereon, characterized in that the deformable beam (6, 16) and its corresponding V. the at least one web (4, 14, 17, 18) are jointly defined in the bottom (3) and in the wall (9) of the pot-shaped body (1) by at least two gaps (5, 15, 25), the tensometric deformation member (11) is formed by the open end of the pot-shaped body (1). 2. Strain gauge according to claim 1, characterized in that the gaps (5) are guided parallel and symmetrically in the plan view of the base (3). Strain gauge according to items 1 and 2, characterized in that the bottom (3) is divided between two previous gaps (5) by another gap (15). 4. Strain gauge according to claims 1 to 3, characterized in that the plane intersected by the contact surface of the base (3) is perpendicular to the axis of the spherical body (1). Strain gauge according to claim 1, characterized in that one arm (13, 23) and its associated web (14, 17, 18) are in the bottom (3) and the wall (9) of the multi-arm deformable beam (16). ) of the pot-shaped body (1) delimited by two curved gaps (25) · 6. Strain gauge according to claim 5, characterized in that the individual arms (13, 23) are symmetrically arranged with respect to the axis of the pot-shaped body (1) and the angle enclosed by two adjacent arms (33, 23) is equal to or less than 180 °. 180 °. Strain gauge according to Claims 1 and 5, characterized in that the planes intersected by the side walls (10) of the deformable beam (6) or the side walls (20) of the arms (13, 23) intersect each other above the abutment surface of the bottom (3). Strain gauge according to claim 7, characterized in that the remaining part of the bottom (3) and / or the wall (9) next to the lateral - 7 of the wall (10) and web (4, 17) or adjacent to the side wall (20) and web (14, 18) is removed. 9 · Strain deformation member according to claims 1 and ^5> characterized in that between the base (2) and the web (17 »18) is formed by a stop gap (12, 22). 10. Strain gauge according to items 1, 4, 9, 6, characterized in that the pot-shaped body (1) has a rotational, e.g. cylindrical shape. Strain gauge according to Claims 1, 5 and 7, characterized in that the deformable beam (6, 16) is weakened at the point of attachment of the strain gauge (7). Strain gauge according to claim 11, characterized in that a place for attaching the strain gauge (7) is provided at the bottom of the annular groove (26) provided in the bottom (3).