SU1593780A1 - Method and apparatus for mechanical working of elongated non-rigid parts - Google Patents

Abstract

The invention relates to mechanical engineering and can be used in the machining of rolled steel, used as blanks or finished products. The aim of the invention is to increase productivity by ensuring the stability of the workpiece in the cutting zone. A rod 20 to be machined, the end of which is pre-machined, is inserted into the holes of the reduction washers 11 and 14. The multi-cutter head is rotated by centrifugal forces, and the head cutters are brought to the surface to be machined. Progressive movement of the bar receives from the puller device 21. Through the pipeline 16 in the treatment area is supplied coolant. The size of the opening of the inlet reduction washer 11 is such that the degree of reduction of the workpiece is (1-3)%. The size of the hole of the output reduction washer 14 is performed taking into account ensuring the degree of reduction of the treated surface of the workpiece in the range of 0.5-1%. In the input reduction washer 11, longitudinal grooves (for example, of a triangular shape) are made that prevent the parts from turning relative to the reduction washer 11 and provide chip splitting during processing. 2 sec. and 3 z. p. f-ly, 2 ill.

Description

The invention relates to mechanical engineering and can be used in the machining of rolled steel, used as blanks or finished products.

The aim of the invention is to increase productivity by ensuring the stability of the workpiece in the cutting zone.

The magnitude of the compression of the material: the billet in the first reduction washer and the degree of compression of the semi-finished product and after cutting in the second reduction washer were selected in accordance with the above calculations. In the calculations, the connection of two parts was considered: a bar and a washer with a hole. Designations: D is the diameter of the reduction hole in the reduction washer, d is the diameter of the outer surface of the reduction: washer. The bar diameter must exceed the diameter of the hole in the reduction washer. It is assumed that only elastic deformations should arise in the joints of the research institutes.

The connection consists of a sleeve and shaft. The difference between the diameters of the bushing and the bushing determines the magnitude of the tension N. When the shaft is pushed, the bushing is stretched by the magnitude K. And the shaft is simultaneously compressed by the magnitude N (j, and the total tension is g N N. N33. with tension. V. limits of elastic deformations; the tension value in a joint is connected; with the size of the joint and assembly conditions, depending on

  pKi: 1;

de r

N D

K ,, E

. WITH,

-pressure on the contact surface of the shaft and sleeve arising under the influence of tension;

- calculated nat;

- nominal diameter of mating surfaces

 the moduli of elasticity of the material of the joint of the 4 bushing sleeve and the shaft;

- coefficients.

bushings 1 +

one

-G

d.W

-Sh

TTT V 2 Mf

0

five

0

five

35

40

45

50

for a shaft without a hole Cr 1 - p,

where G), d - diameters;

t (, and ii are Poisson's ratios

(for steel 1, 3, for aluminum alloy

p ci 0.33).

From the condition of ensuring the immobility of the parts being connected when the joint is loaded with torque

 DlpfD / 2,

from where

2M Ph.D.

where f is the coefficient of friction with relative rotation of parts.

The value of the coefficient of friction (adhesion) ;-( l parts of steel f l 0.08.

The smallest tension g provides immobility under torque loading.

 Mic Rasch

This formula is amended.

and takes into account the roughness of the contact surfaces;

Uj - the difference in the working temperature of the surfaces of the part;

- takes into account the deformation of parts from the action of centrifugal forces;

takes into account the increase in contact pressure at the ends of the reduction washer;

and. - takes into account the effects of vibrations and shocks.

The magnitude of the peak times is calculated using the formulas

55

and

U,

and

VA

and 2 (k, R2 +), where k (and k are coefficients that take into account the value of cm of irregularities of the bore and shaft;

R and R are the heights of the irregularities of the surfaces of the hole and the shaft;

t, - t) - - t) n,

de 0 /, and

/, and t rit D linear coefficients

material expansion

details;

operating temperature

details;

assembly temperature

compounds;

nominal diameter

compounds.

With equal temperatures t. , t

WP-f,

Examples of machining parts. Let the materials be processed: steel 45 and aluminum alloy L16. For external turning of such materials with carbide cutters, the cutting speed is calculated by the formula

Cv

 V

g

and the cutting force, which determines the torque, is calculated by the formula

lOCpt

and.

i - (o (, -o (j) (tp - t) D.

Correction q O, since this amendment is essential for fast-rotating joints and large joint diameters.

The amendment is determined by schedule. The degree of reduction in the reduction washer is determined by the formula

, g (1 -,). 1PO%,

where F, is the initial; cross-sectional area

f1

2 finite sections.

The magnitude of the tension is N D -; where D is the diameter of the rod;

 - diameter of the opening washer.

From where

P D - N; FI

N (2D - N) D2

1GP2

 G - 5 100%,.

The smallest degree of reduction in the reduction washer is determined on the basis of the condition of immobility of the parts to be connected under loading with a high torque. The greatest degree of reduction in the reduction washer is determined on the basis of the absence of plastic deformation on the contact surface of the reduction washer.

von

 0.586

i - v

H dj

AvL

-the limit of the yield strength of the material;

-admissible pressure.

Hence the largest calculated nat g

p AOP

 g P | §4

WITH.)

to,/

The resulting formula also needs to be amended.

15

Then the torque that occurs when cutting the outer layer is equal to

0

M

cr

Pr-D „10Cpt S V b - Z.

Z-K

R

where C

R

five

0

D

T s

V

to to

V

, Y, n, m are constant and exponents for given conditions;

- diameter of the workpiece;

- number of simultaneously working incisors;

 depth of cut, mm;

- submission mm / rev j

- cutting speed, m / min;

- correction factors.

five

0

When machining a steel bar with a tensile strength of 6 J 750 MPa with a cutting depth of t 3 mm, the cutting is prescribed for cutters with additional blades.

S 4 1 mm / rev, then values of C V 292; X 0.30; 0.15; m 0.18. Correction factor

K W - K .. K

Kg

MV

 ov

Where. TO

MV

K (750/6)

hV

1 for steel and carbide

tool, pu 1,

KI; V 1

for

5 hard alloy T15K6. For preparation

K „0.9. So about:

in the form of rolled at once K

At 0.9. Recommended

cutting speed

292

V

N OI8

0.9.

Take the resistance of one tool T 60 minutes, for simultaneously working four tools T-K .. 111 min.

T

Wu

where, 1.85. V 113 m / min

The torque when machining the steel bar is calculated taking into account the coefficients and indicators for the cutters with an additional blade, 0.90; y, 0.90; P

eat Wed 384 | x v., -., J,

 -0.15. Correction factor

Р С. (coefficients are chosen D

and

for (f 45 12 mmo M 68025 N .mm.

7-20). For

The dimensions of the reduction washer D - 12 mm, dy 50 mm, 1 D: mothers of the washer - steel with an elastic modulus of 20--10 N / mm. For such parameters, the coefficients are

1 + (D / dj)

T- (1.422;

1 - 0.3 0.7. The smallest calculated nat

N

/ Amn. calc

2Mcr f С, Q „„ ,,.

 DGDEE71; p ° This value should be increased with amendments. Since the material of the part and the bar is steel, the linear ratios coincide, t „ec of, o (2, and the amendment 11 .. 0.

Roughness correction taking into account the roughness of the hole in the washer 2, µm, the roughness of the outer surface of the bar R 40 µm; And the values of the coefficients kk 0.35: and 2 (29 µm. For connection of such dimensions and c O, P y 8 µm 0.008 mm Subject to amendments, the minimum design tension is g „„ poicu 0.077 mm.

Ddt the implementation of such tension, it is necessary to ensure the degree of reduction

  NMUH (2D - NMHH) - 100%

r

D2

 1.3%.

The greatest degree of reduction in the radius lock washer is limited by the absence of ppastic deformation on the contact surface in the hole of the reduction washer. The material for the manufacture of the reduction washer may be alloyed structural steel after heat treatment. It is assumed that the reduction washer is made of steel 35HGSA., Which, after heat treatment, has a yield strength of 6 1275 MPa. Then for the numerical example in question

extra

0.586

1-t

697 MPa,

The largest calculated nat g

§;) - N

.

087

N

With amendments, the maximum tension of MotKc is 0.124 mm.

To implement such a tension, it is necessary to provide a degree of reduction.

N, "" (2D -) -100%

D2

 2.0%.

Dp processing of the bar from aluminum alloy D16 cutting speed when machining with carbide cutters can be calculated by the formula

20 v

328

о.гг о, g 0,50

2.7 237 m / min

Torque when machining aluminum alloy rod is specified etc taking into account coefficients C. 40; x 1.0; y, 0.75; п О, When processing a bar D 12 mm. with a depth of cut t 1 mm, prii -, ma correction factor K, r 1.5., cr 14400 N mm.

The smallest calculated nat

YG- (M :) in view of amendments minimum namin, rosch

t g 0.048 mm.

For the implementation of such tension, it is necessary to ensure the degree of reduction

 Nd, mn (2G - NMUH) IOO% „„ g, o / o,

The largest calculated nat g when machining aluminum bar

N

MO KS. AOP

РЧР1 С

As amended, the greatest tension g

m "cop

 0.177 mm.

To perform such a tension, the degree of bar crimping is equal to

  .Kc (2D - NMCIKC) -IOO%,

 - J / 0.

Calculations show that it is necessary and sufficient to reduce the amount of bars in the first reduction washer to be within r 1 ... 3%.

15

20

The degree of reduction in the second reduction washer is selected on the basis of the conditions for obtaining a given roughness, dimensional accuracy and geometric Lorma. The magnitude of the degree of reduction is assigned by analogy with the process of surface treatment by plastic deformation.

Thus, for steel 45, with a tension of N 0.05 mm, a surface roughness of R. 0.06 µm is obtained, and with a tension of N 0.10 mm, R 0.07 µm.

The accuracy of processing also depends on the magnitude of the tension. In order to obtain an accuracy of 5-6 qualities, preliminary machining is necessary, after which the deformation is carried out with small tensions, corresponding to a degree of reduction of 0.5 ... 1.0%.

FIG. 1 shows a device for processing parts, a general view; in fig. 2 shows section A-A in FIG. I.

The device for mechanical processing of long non-rigid parts contains a multi-cutter head, which consists of flanges 1 and 2, connected by rigidly spaced stitches 3. And on the flange 1- a drive element is made, for example, in the belt drive pulley 4 and the flanges 1 and 2 are mounted on fixed sleeves 5. and 6, which are mounted on fixed stands — racks 7 and 8, rigidly attached to the base 9.

In the hole of the sleeve 5 with the help of a key 10 is installed reduction washer 11. On the outer surface of the sleeve 5 is mounted bearing 12

A reduction washer 14 is installed in the bore of the sleeve 6 with a key 13. A bearing 15 is mounted on the outer surface of the sleeve 6. In the sleeve 6, the washer 14 has additional openings through which the coolant supply pipe 16 passes. Reducing washers 11 and 14 have openings of different diameters. The hole diameter of the input reduction washer 11 is larger than the diameter of the opening of the output reduction ayb 14. The inner surface of the recovery plates 11 and 14 is formed by forming two truncated conical surfaces and a cylindrical surface 55 of the stem connecting the smaller bases. The angle of inclination of the onous generators is chosen experimentally.

thirty

35

40

45

50

ten

15

20

25

five

thirty

35

40

45

0

Cutter holders 17 are mounted on spacer racks 3, the position of which is adjusted on racks 3 by means of sleeves 18. Cutters 19 are mounted on the tool holders.

The bar-shaped blank 20 is based in the holes of the reduction washers 11 and 14 coaxially with the axis of rotation of the multi-cutter head. On the treated section of the bar, a lock of 21 tons of the lifting device is secured.

In order to improve safety, the multi-cutter head is closed by a protective casing 22, which is attached to the base 9 and has openings for the passage of the part, the mounting of the drive and the opening 23 for removing chips and waste.

When machining parts from a material with a low modulus of elasticity, the compressive force of the workpiece when passing through the inlet reduction washer 11 may be insufficient with the degree of compression recommended by the method. In this case, there is a danger of turning the workpiece relative to the reduction washers 11 and 14. For similar processing conditions, the input reduction washer 11 on the cylindrical section of the profile is made with a splined bore with a triangular tooth profile (Fig. 2). .

The device works as follows.

A bar 20, the end of which has been pretreated to the required size, is inserted into the holes of the reduction unit 1t1x of washers 11 and 14. At the machined end of the bar, the lock 21 of the lifting device is secured. The cutters are adjusted to the desired size of the machined diameter by adjusting their position in the tool holders. The multi-cutter head is rotationally driven, for example, by means of a gear 4. By means of centrifugal forces, the tool holders 17 rotate around the axes of the struts 3, and the cutters 19 come into contact with the workpiece surface and are pressed to it with a force that depends on the mass of the tool holder. 17 and the frequencies of the drives (yeni multi-cutter head.

The bar 20 receives translational motion by means of a second device 21. A coolant is supplied to the treatment zone through a pipeline.

P

The size of the opening of the inlet reduction washer 11 is made so that the reduction of the diameter of the part due to crimping during pulling through the washer corresponds to the degree of compression of g 1 ,,. 3%, gpe degree of reduction .. g: (1 - Fj / Fj) 100% | F, is the initial 4, T h is the final cross-sectional area. The size of the opening of the reduction washer 14 is performed by HJJTETCH such that the reduction in the diameter of the part due to the compression when pulled through the reduction washer 14 corresponds to the degree of compression: 0.5 g ... 1%.

 In the reduction washer 11, the rod 20 is crimped, while the rijemHocTb of the cross-sectional shape is reduced, a more uniform expansion of the allowance for mechanical cutting is achieved.

I With the continuous movement of the rod 2c |), the rotating cutters 19 cut the upper layer of the outer surface of the rod to 20. Since the cutter 19 operates simultaneously, and each cutter 19 has a stripping edge parallel to the axis of the bar, the speed of the longitudinal stirring of the bar 20 can be significant.

The machined rod 20 is drawn through the reduction washer 14, 3 | 5, the bar additionally compresses ™ s and obtains the final diameter ™, the dimensions, the roughness and the shape of the cross section. The pressing force of the bar, developed in reduction gears washers 11 and 14, is sufficient to prevent the turning of the projectile 20 in washers 11 and 14, which play the role of two supports, ensuring high rigidity of the technological system. Simultaneous processing by several cutters 19, symmetrically located with respect to the rod axis, ensures mutual balancing of the radial forces of the cutting forces.

The protective casing 22 prevents clogging of the working area by blasting and other types of waste and preventing it from splashing coolant. Chips and used coolant H are given through a window at the bottom. When machining parts with a small modulus of elasticity, for example, for an aluminum alloy of the D16T type, the slotted hole in the inlet reduction washer 11 deforms the outer

20

25

159378012

the surface of the workpiece, forming on the outer surface the small size of the longitudinal grooves, which, interacting with the slots, oppose. rotation of the part relative to the reduction washer 11 and during the machining by cutting play the role of chipbreaking grooves, since

jQ when cutting, in these places the chips break into elements.

The surface quality is improved, and as a result of the treatment, the surface roughness value is reached.

J5 on the order of Rex 0.32 µm5 deviation from roundness of the cross section on the order of. 5 microns

Formula of the invention;

Claims (2)

1, Method of machining long non-rigid parts, including placing the machined part along the axis of rotation of the machined tools on supports that are installed on both sides relative to the cutting zone, and processing it by telling the axial feed detail about the fact that, in order to improve the productivity of the processing, simultaneously with the machining process, the workpiece is reduced by moving the workpiece through supports, while reducing the raw part of the workpiece dissolved with a degree of reduction of material in 1-3% pre35 affairs. and the treated area - in the range of 0.5-1%. 2. A device for machining lengthy non-rigid parts containing a base with 40 mounted on it incisal head-. With drives for its rotation and supply of cutters, installed in the body of the cutting head, and on both sides relative to the cutting head, supports are provided, characterized in that, in order to enhance performance, each of the supports is designed as a reduction washer basis. 50 3, The device according to Clause 2, of which there is a hole, so that in one of the reduction washers a hole is made with a coolant supply pipe placed in it,. 55 4, The device according to p, 2, about t that is due to the fact that longitudinal grooves are made in the opening of the inlet reduction washer. thirty 45 131593780 5. The device according to claim 4, which is based on the fact that the profile Compiler A, Kornilov Editor A, Shandor Tehred M. Didyk Proofreader M. S ;; mborska Order 2792 Circulation 719 ZNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. D. Production and publishing plant Patent, Uzhgorod, st. Gagarin, 101 14 grooves made triangular. 77 FIG. 2 Subscription