SU1379009A1 - Centring device - Google Patents

Abstract

The invention relates to the field of metalworking, namely, devices for positioning and securing parts on lathes. the invention is to improve accuracy by automatically adjusting when the clamping force is constant. In case 1, a canister 6 is placed with a rotated center and a radial adjustment mechanism. This mechanism is made in the form of a package 8 of piezoceramic plates mounted in an annular groove on the outer surface of glass 6, nMeraniero conical end protrusions 7 interacting with similar surfaces of segments 9. A package 5 of piezoceramic plates forming the mechanism of adjustment movement in horizontal is placed in the central hole of the shank position 1 hp f-ly, 2 ill.

Description

B 8 3 S

(L

12

with x

with

Fi11

The invention relates to metal working, in particular, to devices for positioning and fixing parts on lathes.

The purpose of the invention is to improve accuracy by means of automatic adjustment at constant force; Azhima. FIG. 1 shows the proposed device; in fig. 2 shows an L-.A section in FIG. one.

The proposed device comprises a housing 1 with an installation shank 2, in the central hole of which is fixed through an insert 3 and a conical pin 4 a package 5 of piezoceramic plates adjacent to the end surface and radial direction of the housing 1, the glass 6 is placed in the annular recess of the housing 1 and made in the form of a cylinder, at the ends of which there are annular conical protrusions 7, with their twisted parts facing each other.

The device is equipped with packages of 8 ceramic plates made in terms of the shape of annular segments supported on the conical surfaces of segments 9, which are mated on both sides of the packages of these plates with the conical surfaces of the annular projections of the glass 6. The segments 9 interact with the pressure adjusting screws .mi 10, screwed into a glass. Holes 11 and 12 are drilled in the glass for supplying conductors to the packages of piezoceramic plates.

In the glass 6, the base cone 13 is mounted on the supports 14 - 16 rolling, fixed in the central undercut of the housing 1 by means of the nut 17. The glass 6 is fixed to the R case I by means of the ram 18 through the elastic split profile ring 19, noMenienne between this corner and the front end 6, and the clamp 18 presses the screws 20 through the said ring the entire glass 6 to the bottom of the annular undercut of the housing 1 or to the package of piezoceramic plates in the central hole of the shank 2. In the latter case, the glass 6 interacts with a plate package through the intermediate A gasket 21. A groove 22 is cut into the rear end surface of the cup 6 in the plane of a possible adjustment stroke of the cup 6, with a stop screw 23 screwed into it in the groove.

The device serves to process the part 24. The device can be equipped with two additional packages of a piezo coke. Mimic plates made similarly to the first packages and installed symmetrically with respect to the central axis between the main packages in the bore of the glass. In the usual design of the device, the place of these packages is occupied by fixing inserts 25.

The device operates in the following sequence.

The fastening of the workpiece 24 on the machine, which is carried out when extending the tailstock quill (not shown), is followed by measuring the magnitude of the axial force acting on the part 24. In this case, the cup 6 is displaced in the annular recess of the housing 1 to the right, creating an additional force acting through the gasket 21 on a package of 5 piezoceramic plates. In this package, due to the piezoelectric effect, an electrical signal is proportional to the magnitude of the mechanical loading. The electrical signal is removed from the terminals placed in version 12, amplified and fed to a measuring device (not shown). Using the testimony of the instrument, fixing the part 24 with a predetermined force, sufficient for reliable installation of the part and not allowing axial overload, lead to a curvature of the axis of the parts of low rigidity that adversely affect the operation of bearings 14-16.

After turning on the machine, part 24 begins to sharpen with a longitudinal feed. Under the influence of the radial component

Cutting the part is bent, which leads to machining error. In order to eliminate the error, the automatic adjustment of the position of the part 24 in the radial direction was made, shifting the rear support towards the tool. For this is served

electric voltage on piezoceramic plates 8 packages. Moreover, the polarity of the voltage is opposite when the two packages are applied to the pas. To get the offset parts on the cutter, on the plate 8, located on the back of the base

the side cone 13 applies a voltage, under the action of which an elongation of the plates 8 occurs in the axial direction, and on the plates located in front of the base cone - resulting in a reduction in the axial

the size of the specified plate pack. In that ,", ,

the case uses the reverse piezoelectric effect,

its reversibility, when, when an electric signal is applied to the piezoelectric elements, the latter change their linear dimensions depending on the size of their piezomodule.

When increasing the length of the back pack of 8 plates in the axial direction, a thrust force occurs, acting on segments 9, located symmetrically, from the two ends of the pack.

Segments 9, moving in the axial direction in the bore of the housing 1 and resting on its wall, act on the annular cone-shaped protrusions 7 of the cup 6, its radial direction on the cutter in the horizontal plane. Such movement of the glass 6 is due to the interaction of the beveled at identical angles of the support surfaces of the wedge segments 9 and the protrusions 7 made on the glass 6. The accuracy of the direction of

The horizontal plane is provided with a groove 22 and a stop screw 23 fixed in the glass 1. The magnitude of the displacement of the glass 6 and the base cone 13 is controlled by the voltage applied to the piezoceramic plates. In this case, the housing b is shifted when its cone-shaped protrusions 7 of the wedge segments 9 are moved from the opposite side into the voids formed as a result of the compression of the piezoceramic plates which are there. Thus, the cup 6 of the device is constantly in a stressed and fixed state. Information on the beginning and magnitude of the adjustment of the base cone is obtained from the sensor attached to the machine caliper and moving along with it along the generator part.

If necessary, the adjustment of the position of the base cone 13 is performed in two mutually perpendicular pp) directions, i.e. in the horizontal and vertical planes simultaneously. To do this, additional installed packages of piezoceramic plates are used instead of inserts 25, and the stop screw 23 is withdrawn from the groove 22.

As the part turns, it becomes necessary to adjust the amount of axial force with which the part is attached to the machine. If there is a reduction in the distance between the working ends of the part due to its deflection, then an additional electric voltage is applied to the package 5 of the piezoceramic plates, as a result of which the package length increases. The package is installed in the Central hole of the shank 2, acts through the gasket 21 on the rear end of the glass 6 and shifts the glass together with the base cone 13 in front inside the annular bore of the housing. In this case, the cup 6 moves, resting on the outer bearing surfaces of the wedge segments 9, which are in contact with the housing 1. The plate pack 5 with its rear end is supported on the insert 3, which is rigidly fixed in the shank 2 of the housing 1 with a conical pin 4.

The glass 6, moving in the indicated axial direction, compresses the elastic split ring 19, carrying out a constant tension of the package 5 of piezoceramic plates. Reverse moving base

0

the cone 13 and the body I (the need for which arises with an increase in the length of the workpiece due to its heating during turning) is achieved due to the elastic

the reaction of the split ring 19 and the operation of my workpiece 24 upon a decrease in the electrical voltage applied to the 5 piezoceramic plates of the bag. Information about the need and the required amount of adjustment in the axial direction is obtained from the piezoceramic plates themselves, some of which work in the mode of measuring axial force, as described.

The working tension of the packages 8 is produced by adjusting screws 10 through wedge segments 9, and the package of plates by screws 20 through elastic ring 19, cup 6 and gasket 21. To apply voltage to packages 8 and 5, conductors are laid in holes 11 and 12 respectively.

During the operation of the device, the base cone 13, receiving rotation from the workpiece 24, itself rotates in the bearings 14-16 installed in the cup 6, and

5 g of them are regulated by a nut 17.

Claims (2)

Invention Formula . Center device, in the case of which the glass is placed with 0) 1st rotating s. Center with a shank and a mechanism for its radial adjusting movement, characterized in that, in order to improve accuracy by means of automatic adjustment, when the clamping force is constant, it is provided with bags 5 piezoceramic plates, one of which is located in the central hole of the shank, and the other contains end segments, the outer surfaces of which are made conical, and on the outer bottom of the glass there is an annular groove with conical end surfaces, the latter being designed to interact with conical surfaces the mentioned segments, and the annular groove - for placement of piezoceramic plates. 2. A device according to claim 1, characterized in that it is provided with additional packages of piezoceramic plates installed symmetrically with the axis between the main packages. v:) and g.I