RU2813092C1 - Group method for manufacturing strain resistor force sensors - Google Patents

Abstract

FIELD: instrument engineering.

SUBSTANCE: used for the production in a group method in one production cycle of strain-resistor force sensors for different loads, equipped with parallelogram mechanisms. The method is as follows: in a monolithic block of elastic element blanks, two, four and six through holes of the same diameter are formed perpendicular to its side surface with the same pitch, which are combined into dumbbells in two with horizontal through grooves, then through holes are made perpendicular to the working surface of the block with the same pitch -shaped grooves, forming monolithic parallelogram mechanisms. A matrix of strain gauges is made and, when cutting it into fragments, windows are simultaneously made in them for power-input units, fragments of the matrix are glued onto parallelogram beams, after which the block is divided into discrete sensors.

EFFECT: possibility of simultaneous production of sensors for various loads, increasing their immunity to noise, and increasing measurement accuracy.

2 cl, 4 dwg

Description

The invention relates to a technology for manufacturing parallelogram-type strain gauge force sensors using a group method.

There is a known method for serial production of strain gauge force sensors, which consists of mechanical and thermal processing of a block of elastic element blanks, cutting the block into individual elastic elements and gluing discrete matrices of strain gauges onto their working surfaces [1]. The method is technologically advanced and simple, but does not allow the group production of sensors with elastic elements based on parallelogram mechanisms consisting of two identical, monolithically combined, parallel operating parallelograms.

The closest in technical essence to the claimed is the “Group method of manufacturing strain-resistive force sensors” [2]. It is promising in all respects, but requires special vacuum equipment with a force-setting device inside the chamber, which increases the cost of the sensor manufacturing process.

The purpose of the invention is: the possibility of manufacturing in a group method strain gauge sensors with elastic elements based on parallelogram mechanisms, consisting of two identical parallelograms operating in parallel in a monolithic design. This method makes it possible to create, in one manufacturing cycle, inexpensive, noise-immune from parasitic forces, bending and torques, stable and reliable high-precision sensors for various measured forces.

The goals are achieved by the fact that before the manufacture of U-shaped grooves, on the side surface of the block, with the same step perpendicular to its longitudinal axis O-O, two, four and six through holes of the same diameter are formed, which are combined into dumbbells of two lengths by two horizontal through grooves which ℓ is less than the length of the power supply units ℓ', and the first holes are made at the same distance - “c” from the dividing lines of the block, and the second - at another equal distance - “g” from these lines, with two holes and one groove located along the middle the side surface lines, four holes and two grooves are located at equal distances from the same line, and six holes are located so that two holes and a groove are located along the middle line of the side surface, and four holes and two grooves are located at equal distances from the central groove; then, identical through U-shaped grooves are formed on the working surface of the block, perpendicular to it with a step H, releasing the parallelogram beams from the monolithic block and forming parallelogram mechanisms with power supply units 3 located inside the parallelograms from the monolithic block of blanks; a matrix of strain gauges 4 is made and along the dividing lines they are divided into separate identical fragments 5 so that inside each there are four strain gauges to form a bridge circuit and at the same time a window is formed in an area equal to the area of the U-shaped groove to release the power supply unit when it is glued, install the fragments on the working surfaces of the beams so that the longitudinal axes of the strain gauges coincide with the longitudinal axes of the beams, and their centers coincide with the marking lines on the beams, and matrix fragments are glued in a single cycle, after which the block with the same pitch is divided into ready-made sensors. Thus, in each sensor a parallelogram mechanism is formed, consisting of two symmetrically located, identical monolithically combined and parallel operating parallelograms. When cutting the matrix into fragments, strain gauges, which are located in the cut out windows and the remains of the matrix, are subsequently used to create sensors with elastic elements of any type.

In one manufacturing cycle, depending on the length of the block of blanks L and the cutting step H, several sensors with a monolithic parallelogram mechanism in each can be manufactured.

In FIG. Figure 1 shows a diagram of a group method for manufacturing strain-resistive force sensors with elastic elements in the form of parallelogram mechanisms (front view).

In FIG. 2 - the same diagram (top view).

In FIG. 3 - matrix of strain gauges before cutting into separate fragments.

In FIG. 4 - fragment of a matrix with a window and four strain gauges.

In FIG. 1, 2, 3, 4 the following designations are used: L - length of the block of elastic element blanks; N - step of cutting the block into separate sensors and step of cutting U-shaped grooves; P - “P”-shaped grooves; P1, P2 - parallelograms; (О-О) - longitudinal axis of symmetry of the block of blanks; 1 - first holes with diameter d; 2 - second holes with diameter d; 3 - power supply units; 4 - matrix of strain gauges; 5-fragment of matrix with window; TP strain gauges; ℓ - dumbbell length; ℓ' - length of the power supply unit; a - distances from the middle of the side surface line to two grooves; “b” - distances between three grooves; c - distance from the block cutting line to the centers of the first holes; d - distance from the block dividing lines to the centers of the second holes; c - midline of the lateral surface; 6 - holes for mounting sensors; 7 - lines dividing the matrix into fragments; 8 - lines dividing the block into individual sensors.

The method is implemented as follows: from steel, for example, 35KhGSA, a monolithic block of blanks of length L is made, in the block, using one of the known methods, two, four and six through holes with a diameter d, for example 5 mm, are formed perpendicular to the side surface, respectively, then with a step H, equal to the length of the elastic elements, perpendicular to the working surface of the block along its entire length, through U-shaped grooves are made, for example, using the electric spark method, forming from the block monolithic-united parallelogram mechanisms with power supply units 3 located centrally between the parallelogram beams P1, P2 . On an insulating substrate, for example, from polyamide resin PAI-2I with a foil fixed on it, for example, from constantan, a matrix of strain gauges 4 is made so that the longitudinal axes of the strain gauges, when it is glued, coincide with the longitudinal axes of the beams and are located in the zones of maximum deformation of the beams.

In the matrix 4, before the sticker, when cutting it into fragments, to release the force-conducting units, windows are simultaneously formed, the area equal to the area of the U-shaped grooves, and the strain gauges, which are released in this case, having previously divided them element by element, are used for their intended purpose to create strain gauge sensors. Fragments of matrices 5 with the same pitch are installed on the surface of the beams so that the longitudinal axes of the strain gauges coincide with the longitudinal axes of the beams, and their centers coincide with the marking lines on the beams and in a single cycle they are glued to the block of workpieces.

In comparison with the known ones, the proposed method has the following advantages:

1. Allows us to simplify the manufacturing technology of sensors with monolithic parallelogram mechanisms, since its implementation does not require special vacuum equipment with a force-setting mechanism inside the chamber, which reduces energy consumption and, accordingly, the cost of sensors.

2. Allows the production of sensors for different forces, containing monolithic parallelogram mechanisms, in a single cycle.

3. The proposed method can be automated.

Sources of information accepted during the examination:

1. Auto. USSR Certificate No. 1258169 A, Kl-G01L 1/22, 1984.

2. Decision dated July 28, 2023 on the grant of a patent for an invention under the application for “Group method for manufacturing strain-resistive force sensors” No. 2023102341/ 28 (004992).

Claims (2)

1. A group method for manufacturing strain gauge force sensors, including mechanical and thermal treatment, manufacturing elastic element blanks with the same pitch of identical through U-shaped grooves in a block, sticking a matrix of strain gauges onto the working surface of the block and cutting the block into separate sensors, characterized in that the front by making U-shaped grooves on the side surface of the block with the same pitch perpendicular to its longitudinal axis O-O, two, four and six through holes of the same diameter are formed, which are combined into two horizontal through grooves into dumbbells, the length of which is less than the length of the power supply units, and the first holes are made at the same distance from the dividing lines of the block, and the second - at another equal distance from these lines, with two holes and one groove located along the center line of the side surface, four holes and two grooves located at an equal distance from the center line, and six holes arranged so that two holes and a groove are located along the middle line of the side surface, and four holes and two grooves are located at equal distances from the central groove. 2. A group method for manufacturing strain gauge force sensors according to claim 1, characterized in that the matrix of strain gauges along the dividing lines is divided into separate identical fragments so that inside each there are four strain gauges to form a bridge circuit and at the same time a window is formed with an area equal to the area of P- shaped groove, to release the force-introducing unit when it is glued, the fragments are installed on the working surfaces of the beams so that the longitudinal axes of the strain gauges coincide with the longitudinal axes of the beams, and their centers coincide with the marking lines on the beams, and matrix fragments are glued in a single cycle.

Images