SU1396062A1 - Mobile system of electric measuring instrument - Google Patents

Abstract

The invention can be used in the mass production of electrical measuring instruments with fastening of the system on extensions. The mobile system (PS) of the electrical measuring device contains a frame 1 on extensions 2, a magnetic system with a working gap 3, a cylindrical rod 6 passing through the through axial hole 7 of the core 5, a balancing unit in the form of a hollow cylinder (PC) 8 with double walls between which there is a viscous hardening material. In the walls of the PC 8, uniformly circumferentially, there are through radial slots into which the plates 10 with the restraints 11 are inserted in the axial plane, the mass m and the length of which are 1 m, t ,,. 2 hee m / s; 1 m „l X R and / т e AOP where m is the mass of the PS; R is the outer radius of the cylinder; ,. and fton - maximum possible and maximum allowable values of transverse eccentricity of PS; And - step displacement of the plate 10, PS has a high accuracy. 2 Il. cl

Description

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The invention relates to a measurement technique and can be used in the mass production of electrical measuring instruments with fastening of the system on stretching.

The aim of the invention is to improve the accuracy.

FIG. 1 schematically depicts a movable system with a central section, front view; in fig. 2 - the same, top view.

The mobile system of the electrical measuring device contains a frame 1; mounted on extensions 2 and located in the working gap 3 of the magnetic system formed by a permanent magnet 4 and an intraframe core 5; In frame 1 there is a central cylindrical rod 6 passing through a through axial hole 7 made in the core 5; On the frame 1 there is a balancing assembly, made in the form of concentrically fixed on the rod through the axial hole in the bottom of the hollow cylinder 8, which has double walls with a gap between and filled with viscous hardening material 9. In the walls of the cylinder, uniformly circumferentially made through radial slots, in which the plates 10 are loosely inserted: in the axial plane of the plate 10, which have limiters II of the radial displacement in the peripheral direction (abutments ), and the plates are set in such a way that their outer and inner ends are located respectively in radial gaps between the outer wall of the cylinder and the wall of the axial hole in the core and the inner wall of the cylinder and the stem. The design parameters of the plates (mass m5l and 1 - length) are selected using the following ratios:

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2 m pl R l

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where w is the mass of the moving system; R is the outer radius of the zips; e is and e. j is the maximum possible and maximum allowable value of the transverse eccentricity of the mobile system; s;

and - practically realizable minimum (step) plate displacement.

The automatic balancing of the mobile system is as follows.

In the initial position (Fig. 1), the plates 10 are inserted into the slots in the walls of the cylinder 8 up to the stops 11, while on the outer side of the plate a little does not reach the walls of the hole 7 in the intraframe core. The distance between the inner end of the plate 10 and the rod 6 is such that the plate can be almost completely pressed from the outside into the cylinder 8, while its outer end will be almost flush with the outer wall of the cylinder 8.

The balance device is installed in a vertical position on the centrifuge platform so that the axis of rotation coincides with the axis of the moving system. The centrifuge, together with the device, is driven into rotation with an angular velocity n determined by the formula

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where s is the natural frequency of transverse oscillations of the moving system; c / -i (radial clearance between the outer wall

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koi cylinder o and the wall of the axial bore 7 in the core 5 (Fig. I). This speed provides balancing of the moving system with the given one. accuracy. Since the center of mass M of the moving system (Fig. 2) in the general case does not coincide with its axis of rotation C by the magnitude of the transverse eccentricity vector e, the rotation causes centrifugal inertia forces proportional to the value of eccentricity e and pulling the deflection of the movable SYSTEM on stretching from the axis of rotation in the direction of the vector e. Since the transverse rigidity of the moving system on the extensions is much greater than the torsional, the deviation over the entire height of frame 1 occurs by almost the same value, i.e. cylinder 8 moves progressively in the direction of vector e. The position of the plates 10 according to the height of the frame of the poetach is indifferent, static and dynamic balancing in

In this case, the same. When the cylinder 8 deviates together with the plate frame 10, the outer ends of the hole 7 are pressed against the walls and the lostepeino is pressed into the cylinder (only the plates pressed in the direction close to the vector e from the center of mass M are pressed, since it is this place that the cylinder 8 presses to the wall of the axial hole). As the eccentricity plates are pressed in, e decreases, the force of the pressure fades, and eventually the plates are pressed into

until the eccentricity is less than the allowable value, n the wall of the hole 7 no longer presses the plate, but only touches it. As the plate is pressed in, it does not abruptly move towards the axis of the moving system, which could cause an unacceptable discontinuous change in imbalance. This is due to the fact that the plates 10 themselves are displaced relative to the axis of rotation and due to their own centrifugal inertia forces all the time are pressed in the peripheral direction: in the initial position by stops I1 to the inner wall of the cylinder 8, and in the process of displacement to the axis due to their own centrifugal forces - to the walls of the hole 7, which prevents the occurrence of shocks and bounce. The process of displacing the plates 10 to the axis of rotation of the frame until complete imbalance is described as a smooth process, but in reality everything happens almost instantly: the required rotation speed is selected, the necessary parameters of the plates are preselected, the moving system deviates in the direction of the unbalance vector The vector e is in contact with the wall of the axial bore 7, and is pressed into the groove.

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However, it remains all the time pressed against the wall of the hole. After that, the device is continued to rotate until such time as the viscous material 9 begins to harden and the plates 10 are not locked in the final position, then the device is removed from the centrifuge and allowed the material 9 to finally solidify.

Claims (1)

Claims of the invention A movable electrical measuring instrument system comprising an axis on which a frame with a working winding and a balancing unit is located, characterized in that, in order to improve the accuracy of balancing, a cylindrical rod located coaxially with the axis is inserted into it, and the balancing unit is made double-walled hollow cylinder, between which a viscous hardening material is located, and plates with radial displacement restraints, are evenly placed perpendicularly cylindrical with rod in the through radial slots made in the cylinder walls, with mass m „. and the length of 1 each 1 p 30 (Plates satisfy the following ratios: m pl R l m e qon de m R e mass of the moving system; outer radius of the cylinder; the maximum possible value of the transverse eccentricity of the moving system; the maximum permissible value of the transverse eccentricity of the moving system; L - step displacement of the plate. dop cpue.Z