SU952443A1 - Apparatus for program control of thin-wall cylindrical part working - Google Patents

Description

The invention relates to the automation of production processes and can be used in the processing of parts such as thin-walled rings, sleeves, cylinders, etc., on machine tools.

A device for turning non-rigid parts is known in which the ends of the workpiece are fastened in two clamping devices and a tensile force 1 is applied to the rear end of the workpiece.

The disadvantage of such a processing circuit is that parts of the part (ends) located in the clamping devices cannot be processed and in most cases are cut off, i.e. go to waste. This requires an additional operation, an additional tool and leads to a non-economical use of the workpiece material. In addition, it is practically impossible to use stretching for thin-walled cylindrical parts of large diameter, since very great efforts are required, which in turn require special tooling and J-specific machines with increased bed rigidity, requiring the use of special tools.

spindle bearings, powerful drive. Special requirements for this are made with clamping devices for securing the part. They must ensure reliable fastening, without the possibility of slipping (sliding out) of the part relative to the clamping elements, as well as the absence of deformations of the part in places of application of clamping forces, which lead to a change in the shape of the roughness of the machined surface (cut, ellipsity, spacer, etc.).

15

It is also known a device consisting of serially connected control units of the actuator, adjustable stiffness unit, displacement sensor, program setting unit, position sensor, the input of which is connected to the actuator, and the output to the control unit, and tension unit the workpiece, with a series of series-connected threshold elements, pressure transducers, And 2 elements.

The disadvantages of the known device include the practical impossibility of using it in the processing of liners or cylinders of large diameter, since in order to increase their rigidity in the radial direction by 15–20%, tensile forces of about tens of thousands of kilograms are necessary. It is practically impossible to fix securely a large-sized part, for example, D 200 mm in diameter, with a wall thickness of 5-7 mm and a length of L 500-800 mm, using known clamping devices without seeing its ends or changing shape. In addition, it is practically impossible to use this processing scheme on the existing technological equipment, since neither the beds, nor the spindle units, nor the individual aggregates of conventional machines are designed to reproduce such loads, and the creation of new, special machines will require considerable time and money. cost When machining large diameter parts (over 200 mm), it is first necessary to avoid local (local) deformations of the part walls that occur at the point of contact of the cutting tool with them, and not the formation of the whole part, considered as a double support beam, since the rigidity of the tubular parts in the radial direction exceeds that of the solid parts. Therefore, the use of this device is inefficient. The aim of the invention is to simplify the design and improve the accuracy of processing thin-walled cylindrical parts. The goal is achieved by those. In a device comprising a series-connected comparison unit, an actuator, an adjustable stiffness unit, a tool displacement sensor in the longitudinal direction, a program setting unit, an element AND whose output is connected to the comparison unit, a transverse displacement sensor , the input of which is connected to the executive mechanism, and the output is connected to the comparator unit, and the deformation unit of the part are introduced in series by the connected pressure-regulating mechanism, the regulator pressure torus, pressure sensor, amplifier and the second comparison unit whose output is connected to the second input of the element I and to the input of the drive mechanism of the pressure regulator, the second input of which is connected to the output of the program setting block, and the pressure sensor is also connected to the part deformation block designed to deform it in the transverse direction, consisting of a rack mounted on a machine caliper with brackets containing holes at the ends, made normal to the work surface, in which tails are placed The bellows bellows with interconnected channels for supplying the working fluid, and their other shanks, carrying limbs and rollers, are mounted on the ends of flat springs fixed by their central parts on the brackets, and the bellows with shanks are installed in the holes of the brackets and flat springs with adjusting the angular position of the rollers with respect to the axis of the workpiece and are enclosed in glasses associated with the shanks with pins and spikes. FIG. 1 is a block diagram of the device; in fig. 2 - power element of the deformation unit of the part; in fig. 3 is a section A-A in FIG. 2; in fig. 4 - deformed thin-walled sleeve; in fig. 5 is a section BB in FIG. 4. The device (Fig. 1-3) contains an adjustable stiffness block 1. (tool block), a sensor 2 for longitudinal movement of the tool, a program setting unit 3, an AND 4 element, a first comparison element 5, a tool 6 transverse movement of the tool, the first actuator 1, a second actuator 8, a pressure regulator 9, a pressure sensor 10, an amplifier 11, a second comparison element 12, and a unit of deformations of the part in the transverse direction. The device is connected to the machine tool-tool-part (SPVD) system by the output of unit 1 and the output of sensor 10. The deformation unit of the part in the transverse direction consists of a vertical stand 13 fixed to the machine support with brackets 14 carrying the power elements normal to the workpiece 15 The force elements are bellows 16, some of the shanks 17 of which are placed in the holes of the brackets 14 and have channels 18 for supplying the working fluid, and the other shanks 19 containing limbs 20 and rollers 21, are placed The holes in the holes made at the ends of the flat springs 22, fixed with their middle parts on the brackets 14. The sylphons are placed with a gap in the cups 23, which connect the shanks to each other through the pins 24 and studs 25, the latter being placed on the slide fit The cut-outs of the flange of the shank 19. In order to ensure the conditions of self-feeding of the deformation block along the axis of the part 15, it is possible to position the rollers 21 at an angle relative to the axis of the part. Required

the angle of rotation of the rollers is determined from the ratio

where Sg is the value of feed per one

turnover of the workpiece;

D is the diameter of the workpiece.

The provision of the required angle of rotation of the roller is carried out with the help of nuts 26, 27 and limb 20, containing turnkey flats on its cylindrical part (not shown).

The device works as follows.

Part 15 is fixed on the inner | Nei surface in the clamping fixtures of the front and rear headstock of the machine, and the cutting tool in block 1. The part of the length of B (Fig. 4), equal to the width of the fixture fixture, is processed with one longitudinal tool feed without deformation of the part in the transverse direction. In this area, the effect of the radial component of the cutting force is perceived by the clamping elements of the devices and the workpiece does not deform in the radial direction (local deflection) under the action of this force. The block of deformation of the part in the transverse direction moves after the cutting tool and after processing the section of the part of length B, block 3, in accordance with a predetermined program, according to signals from the sensor of longitudinal movement of the tool 2, generates a voltage pulse that enters the actuator 8 of pressure regulator 9 which opens the access of the working fluid (liquid) to the bellows 16 of the power elements, which unclench, through the rollers 21, deform the part, giving it the shape of an ellipse whose large axis coincides with The pressure effect of the radial component of the cutting force T (FIG. 5). The magnitude of the radial increment of the detail S can be determined from known formulas or tables (3).

The increment S is uneven along the length L of the part due to the edge effect caused by fixing the part in the clamping devices. The influence of the edge effect on the increment value is completely excluded at a distance (B + K). From the ends of the part, i.e. throughout the remainder of the part, the FoOE ® Route. Uniformly. The value of K can be determined with sufficient accuracy for practical purposes from a known expression.

h i

.K 1.85 5 where h is the wall thickness of the part.

When machining parts with a length of K, the tool, in addition to the longitudinal feed, must be reported to cross feed, that is, at the beginning of machining, smoothly divert to

value 2 S, and at the end of processing to bring on the same value. By knowing the maximum radial increment of a part, determined from the difference (D + 28) -D and distributing it evenly over a part length K, it is possible to ensure with sufficient accuracy for practical purposes the required tool movement path defined by the dependence

Qnon

where a. - cross feed instumenta.

The tool is retracted from the deigali by a command from the software device 3 only

when the pressure in the line supplying the bellows reaches a predetermined value and at the output of the pressure sensor 10, a signal of the required magnitude comes in through the amplifier 11 to the reference element 12, which also receives a voltage pulse, from the device 3 corresponding to the required pressure value. When these two signals are equal, device 12 generates a signal

arriving at one element of the element and 4 and simultaneously at the actuator of the pressure regulator 9, disconnecting it.

Simultaneously with the process of deforming the part in the transverse direction, in accordance with a predetermined program for changing the transverse feed, the signals from the program

device 3. From the output of the element And 4

an electrical signal is fed to one of the inputs of the comparison element 5, to the second input of which is fed a signal from the transverse displacement sensor of the tool 6. The error signal from the output of the element 5 is fed to the motor of the actuator 7, which moves the movable stop of the block 1 to the position providing the elastic retraction of the tool from the part to the desired value.

When processing the second section K, the tool smoothly leads to the workpiece and at a distance B from the end of the part, at the command of sensor 2, the program device 3 turns off the working fluid supply to the bellows 16. The rollers 21 retract due to the energy of elastic deformations accumulated in bellows

Claims (3)

and flat springs 22. Unlike rigid lunettes, the device for deforming a part in the transverse direction does not transfer the errors of the machine guides to the workpiece, because, due to the presence of elastic elements in the form of bellows, which communicate with each other by channels for supplying the working fluid, it is like It would be relatively dry, ensuring at the same time a given value and equality of all four forces F, acting on the part and deforming it. As a result of deformation, the curvature of the section of the part facing the cutting tool increases, and consequently, the resistance of the part to the action of the radial component of the cutting force increases, which leads to a decrease in the local deflections of the part at the site of application of this force. Internal stresses created in the part when it is deformed within the limits of elasticity, reduce the possibility of self-oscillations and, therefore, contribute to improving the quality (purity) of the treated surface. The same is facilitated by rolling with rollers, through which the part is deformed by the forces of F. It should also be noted that the rigidity of the whole part in the radial Direction, considered as a two-support beam, increases due to the shape of the ellnps in the transverse direction, i.e. Its resistance to bending from the radial component of the cutting force increases. Formula of the Invention A device for programmatically controlling the processing of thin-walled cylindrical parts comprising a series-connected comparison unit, an actuator, an adjustable stiffness unit, a tool displacement sensor in the longitudinal direction, a program setting unit, an AND element , the output of which is connected with the comparison unit, the transverse displacement sensor of the tool, the input of which is connected to the actuating mechanism and the output is connected to the comparator unit, and the deformation unit of the part, characterized in that, in order to simplify the design and improve the accuracy of processing thin-walled cylindrical parts, the device is connected in series with a drive mechanism of a pressure regulator, a pressure regulator, a pressure sensor, an amplifier and the second comparison unit, the output of which is connected to the second input of the element I and the input of the drive mechanism of the pressure regulator, the second input of which is connected to the output of the program setting block, the pressure sensor also connected to the deformation unit of the part intended to deform it in the transverse Direction and made of a rack mounted on the machine support with brackets at the ends of which holes are made along the normal to the machined surface in which the shanks of the bellows are located with interconnecting channels for supplying the working bodies, and their other shanks, carrying limbs and rollers, designed to interact with the part, are mounted on the ends of the flat springs fixed by their central parts on the brackets, the bellows with the shanks are installed in the holes of the brackets and flat springs with the possibility of adjusting the angular position of the rollers relative to the axis of the workpiece and are enclosed in glasses associated with the shanks with pins and spikes. Sources of information, rintye taken into account in the examination, 1. The author's certificate of the USSR № 118676, cl. B 23 B 1/00, 1959. 2. Authors certificate of the USSR 658530, cl. B 23 B 1/00, 1979. 3. Korsakov B.C. Fundamentals, the design of fixtures. M., Mashinostroenie, 1965, p. 45-48