JPS62211526A - Mechanism for receiving force or pressure having split leaf spring so that bending moment is not generated - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a mechanism for receiving forces or pressures, which has a leaf spring fixed on at least two sides to a sufficiently rigid frame.

In prior art mechanisms for receiving forces or pressures, so-called leaf springs are often used as elastic measuring elements, the chi-shape of which is proportional to the measured value, for example in elongated measuring strip mechanisms or capacitive measuring elements. It is converted into an electrical measurement signal by the momentum receiving element.

The simplest shape of a leaf spring is a straight beam,
Uniaxial tension is created in this beam by forces perpendicular to the beam direction. Also common leaf springs (so-called circular leaf springs with circular edges) which are tensioned in many planes or all over, and exhibit biaxial mechanical tension when loaded with force or pressure. It is also widely used. These leaf springs must be manufactured in one piece with the outer flange in order to form a strong clamping at the outer edge, since the split flat leaf springs and the separately manufactured clamping 7 runzo This is because, in conventional constructions with 200 mm, the connection cannot be formed without reaction forces due to the relatively high bending moments at the tightening points. In the case of a receiving mechanism with glued elongation measuring strips, the above-mentioned built-in structure does not involve any major drawbacks in terms of manufacturing technology, whereas when using the technology of thin-film elongation measuring strips, the above-mentioned built-in structure This results in high costs, since in this case it is possible to achieve profitability only with batch-processed sheet metal substrates. However, the required strong built-in 7-lantern cannot be formed using a single thin plate with parallel planes.

According to US Pat. No. 3,621,435, for example, a force or pressure receiving mechanism is known with a leaf spring consisting of at least two parts, of which only the first inner part is deformable. and almost flat
the second outer part surrounds the outer region of the elastic leaf spring, and furthermore, only the first inner leaf spring part is used for the production of deformations caused by force or pressure. It has become.

OBJECTS OF THE INVENTION It is therefore an object of the invention to use a flat, elastic sensing element, for example a circular element, with e.g. a thin film-like elongation measuring strip, but without the need to insert the core into a solid frame, a directing element. The purpose is to ensure that the fixation of the spring does not have any adverse effect on its spring characteristics.

According to the invention, the above-mentioned problem is achieved in that: a) the leaf spring consists of at least two parts, only the inner first part being formed as a deformable and substantially flat plate; and the second outer part surrounds the outer region of the elastic leaf spring and the adjoining sufficiently rigid frame, b) the connection point between said parts of the leaf spring is C) Detection of deformation caused only by force or pressure on the inner first leaf spring portion, which is formed at a location where the bending moment perpendicular to the bending point is so small as to disappear. It was solved by being used for.

Effects and Effects of the Invention According to the present invention, the elastic measuring member (plate spring) is divided into two parts, namely the inner original detecting member (which also holds the electrical deformation sensor), unlike the conventional one-piece structure. ) and an outer holder, the connecting part of which is also elastically deformable, acting as a suitable bending hinge, so that a bending force-free connection point is created between the two parts. Formable. Despite its simple coupling technique, the receiving mechanism of the invention does not introduce any disadvantageous mechanical or thermal hysteresis phenomena due to the structure of the bending hinge described above.

Implementation mode The basic idea of the invention is shown in FIG.

Partial diagram 1a shows a simple flat bending beam that is clamped on both sides and loaded symmetrically. Partial diagram 1
b shows the bending moment history in the longitudinal direction of the bending beam of partial figure 1a, the bending moment being
The positions x and X' pass through zero at this point, ie, the two arms (shown in FIG. 1C) that are split at this location can be coupled without creating a moment here. That is, the frame is constructed as a self-contained body consisting of a fixed clamping edge 13 and partially bent beams 2, 3, which act as actual elastic measuring elements at points x1 and X1' (±total length τ). 1 to the simple central member 1. There is a small amount of money. Only this central part carries the actual sensor mechanism 14, by means of which the load-proportional deformations are converted into signals that can be evaluated electrically. The relationship in each spring element with two dimensions (circular leaf spring, square leaf spring or oval leaf spring) is completely similar both at the point load F shown and at the high zero static pressure P.

Only the points x1 and X1' can be varied depending on the respective elastic static load, i.e. in the case of a flat circular leaf spring (radius a), for a central point load F, x1 = [1,46·a1
For a reservoir of hydrostatic pressure P, X1'=0.
63・a applies (horizontal, shrinkage rate r = 0.5)
.

In each leaf spring with two dimensions, a finite compensatory stress also occurs at these points X1 and X1' where the respective longitudinal stress is eliminated, but this stress always extends through the dividing point. Therefore, no mechanical stress occurs on the connection, so that in theory this connection can be carried out by a simple mounting at points x1 and X1'.

However, welded or brazed seams are even more preferred.

In the above dimensional design, the edge tightening has ideal strength, and the strength (E/work) in each deformed member 2/3.1 in Fig. 1C
This applies if they are the same. Edge conditions (elastic deflection of 7 lunges) which are not necessarily optimal are xl and x1'
can be compensated for by shifting some in the direction of green. On the other hand, near each dividing point, the outer elastic member 2/
3 and the inner actual detection element 1, care is taken to create the same strength, since otherwise the principle of a bending-moment-free connection point would not be fulfilled.

Of course, it is also possible to form a leaf spring by a known method such as a plate spring and use it here, separately from the dividing point. In the pressure-receiving device, this is a reinforcement of the edge area, while in the force-receiving device, it is advantageously an additional reinforcement of the central part that carries the point load.

The formation of the electrical deformation sensor on the central elastic sensing element is preferably carried out on the principle of an elongated measuring strip or capacitively. An example of this is shown in FIGS. 2 and 3. In the case of the elongated measuring strip according to FIG. 2, only one pre-elongated code is used, so that only one asymmetrical, semi-active bridge circuit is formed. For this reason, the second
The two elongation measuring strips 4'4' shown in the figure serve as temperature-compensating resistors, which are formed from the same elongation measuring strip material as non-extensible, so-called passive resistors and mounted separately. obtain.

In the case of thin film-like elongation measuring strips, uncovered nip-like regions, which remain between the circles, for example, serve for this purpose.

The capacitive sensor arrangement shown in FIG. 3 consists of two ring-shaped electrodes 5.5', one of which is arranged on an insulator holder 6. In this case, the insulator holder 6 (as schematically indicated by the column 1) is fitted in the center of the inner leaf spring part 21' and, when loaded, joins the inner leaf spring part 21'. descend to In FIG. 2b, the force input is again schematically indicated by the hook 1B. In the example of FIGS. 2 and 3, the inner outer walls 23 and 23'
corresponds to the fixed clamping edge 13 of FIG. 1C, and the protruding elastic region 22.degree.
．． 3 and the inner elastic plate 21.21' functionally corresponds to the central member 1 in FIG. 1C.

FIGS. 4 and 5 show two alternative embodiments based on the above-mentioned principle.

The pressure receptor in the example of FIG.
In its center, it has a circular detection plate 31 with ``. The above-mentioned temperature-compensating resistor 15, which is arranged on the wall of the housing part 33, the integrated electrical plate 8 and the connecting cable 9 are arranged.

FIG. 5 shows a precision force receptor for small forces. This instrument consists of a small square plate made of sapphire.
It is made up of an inner detection element designed as 0 and a frame 11 made of an elastic sheet whose strength at the joining point is matched to that of the sapphire sheet. This connection takes place in this case at point 12, for example by means of a eutectic noble metal solder. A thin plate-like extension measuring strip 4'' made of alloy is used here as the extension detector. The force introduction takes place at the central point 17, and each point 16 of the frame 11 is used for the fixed support of the housing. to work.

The inventive theory of split leaf springs so that no bending moments occur has two different usage variations. 0 Only a very small area is required for the active detection element, and the thin-plate sensor can nevertheless be produced inexpensively, since the necessary rigid flanges can nevertheless be used. Detection platelets made from thin sheets can be produced and coated in a parallel process as multiplets.

In the case of expensive spring materials that are difficult to work with, such as sapphire, which is extremely brittle and easily broken, the invention provides significant advantages with respect to the material and manufacturing costs and resistance to alternating loads.

[Brief explanation of drawings]

The drawings show several embodiments of the invention, the first
Figure a shows a bending beam tightened on both sides, Figure 1b is a diagram showing the bending moment history of the bending beam of Figure 1a, Figure 1c shows a bending beam formed in segments,
2 shows a top view and a sectional view of a force receptor with an elongated measuring strip, FIG. 3 shows a sectional view of a force receptor with a capacitive sensor, and FIG. 4 shows a pressure receptor with a casing. FIG. 5 is a plan view showing a stress receptor according to another embodiment. 1... Detection member, 2, 3... Portion 1 bending beam, 4
, 4', 4', 4''... extension measurement strip, 5
．． 5'... Electrode, 6... Insulator holder, 7... Welding joint, 8... Electrical plate, 9... Connection cable, 10... Small thin plate, 11... Frame, 12 ...
Part 13...Tightening edge, 14...Sensor mechanism,
15... Temperature compensation resistor, 16.17... Point, 18
...Hook, 19...Strut, 21.21'...Plate, 22, 22'...Elastic range, 23°23'...
Outer wall, 31...Detection solate, 32.33...Casing part 2 EZ? 4 Two TbC5

Claims (1)

Claims: 1. A mechanism for receiving force or pressure having a leaf spring fixed on at least two sides to a sufficiently rigid frame, comprising: a) a leaf spring in at least two parts (1, 2, 3, 10
, 11, 21, 21', 22, 22', 31, 32), and the inner first part (1, 10, 21, 21
', 31) are designed as deformable and approximately flat plates, and the second outer part is formed by the outer regions (2, 3, 11, 22, 22',
32) followed by a sufficiently strong frame (13, 23
. c) a leaf spring segmented in such a way that no bending moments occur, characterized in that only the inner first leaf spring part is used for the detection of deformations exerted by forces or pressures; mechanism for receiving force or pressure. 2. The inner first leaf spring portion (21, 21', 31) has a circular, oval, or square shape, and the outer second leaf spring portion (22, 22', 32) A mechanism for receiving force or pressure according to claim 1, which is coupled with 32). 3. Mechanism for receiving force or pressure according to claim 1 or 2, wherein the inner first leaf spring part (21, 21', 31) consists of a sheet metal. 4. The connection between the inner first leaf spring part (21, 21', 31) and the outer second leaf spring part (22, 22', 32) is performed by gluing, soldering or welding. ,
A mechanism for receiving force or pressure according to claim 3. 5. The inner first leaf spring part (10) is made of quartz glass, silicon, or sapphire, the outer second leaf spring part (11) is made of metal, and both of these leaf spring parts are made of low-temperature melting material. Mechanism for receiving force or pressure according to claim 1 or 2, which is connected to each other by solder. 6. The force or pressure according to any one of claims 1 to 5, in which a capacitive momentum measuring member (5, 5') is used as a sensor for detecting deformation. A mechanism for accepting 7. Stretch measuring strip (4,
Mechanism for receiving force or pressure according to any one of claims 1 to 5, characterized in that 4', 4'', 4''') is used. 8. In addition to the active lamellar elongation measuring strip (4") on the inner first leaf spring part (31), another lamellar elongation measuring strip manufactured by the same lamellar elongation measuring strip process In the unloaded state, the elongation measuring strip (15) acts as a passive reference resistor,
Claim 7 arranged for temperature compensation
Mechanism for receiving the force or pressure described in Section 2.