RU1794633C - Method for working surfaces of rotation of blanks - Google Patents

Abstract

Usage: when machining precise external surfaces of rotation in parts such as rings of rolling bearings. SUMMARY OF THE INVENTION: The loads are connected to the corresponding bar and set them on different sides of the workpiece to be moved together relative to the latter. The bars are interconnected by elastic elements. The preform is rotated in the direction of rotation of the bars. The rotation speed of the bars is selected from the above conditions. 4 ill.

Description

The invention relates to mechanical engineering. It can be used in machining precise external surfaces of rotation in parts such as rings of rolling bearings, sleeves, etc. .

As a prototype, the processing method is the closest in its technical essence and the achieved effect, in which abrasive bars are pressed against the workpiece surface to be processed and the bars and the workpiece are rotated:

However, the prototype method does not provide the required performance and processing quality.

The aim of the invention is to increase the productivity and quality of processing of external surfaces.

The rotation speed of the bars for this is chosen from the condition

Vmin V Vmax,

 .V bmm - b + r-GTTG t {1)

V

max

.V bmax + B + M + T-2

, (2)

V Vfl + Vp; A 30-D; Bt) p

 10- Qmin S; Btah 10 Qmax S;

B (MI + Mr) 1 g; Mr Mr -R2 Mi -Ri;

D is the calculated diameter of the treated surface;

Qmin is the average value of the minimum pressure force;

Qmax is the average value of the maximum pressure;

Mi is the mass of bars;

Mg is the mass of cargo;

S is the projection area of the bars on the axial plane;

RI is the radius of the center of gravity of the bar;

Ra is the radius of the center of gravity of goods;

FI and F2 are the elastic forces of elastic elements;

Ud is the speed of rotation of the part;

Vp is the cutting speed.

In FIG. 1 shows a device for implementing the method, a longitudinal section; in FIG. 2 - also, side view; in FIG. 3 is a diagram of the relative position of the bars and the work surface and the acting forces in the extreme upper position of the bars;

ate

smiling s

CA)

in FIG. 4 - the same, in the extreme lower position of the bars,

A method for treating workpiece rotation surfaces in static. - Billet 1, for example, the inner ring of a ball bearing, is installed in the fixture, not shown conditionally, of the internal grinding machine. The workpiece 1 has a central axis of symmetry I-I, the machined surface 2, the axis of symmetry of which coincides with the axis I-I. The blank 1 also has a plane of symmetry II-II perpendicular to the central axis of symmetry l-l. The surface to be treated 2 may have any shape of the outer surface of rotation, for example, the shape of the outer toroidal surface. The tool consists of 3.4 bars, for example, abrasive, body 5, mounted on the spindle 5 of the machine. The bars 3, 4 are fixed in the holders 7, 8. On the holders 7, 8 are fixed earrings 9, 10 and eyelets 11,

12. Earrings 9, 10 are rigidly, for example, by means of pins, connected to columns

13. 14. Columns 13, 14 are rigidly fixed at one end to one load 15, and the second are connected in a movable landing with an oppositely located load 16. The eyes 11,12 are connected to the columns 13, 14 in a movable landing, and by means of a bar 17. 18 rigidly connected to the loads 15, 16. Between the earrings 9, 10 and the eyes 11, 12 compression springs 19, 20 are arranged in pairs. The weights 15, 16 are connected to the housing by means of the guides 21, 22 and extension springs 23, 24 and are able to move along the guides 21.22. At the same time as the weights 15, 16, the holders 7, 8 together with the bars 3, 4 are also able move radially to and from axis II as a whole. Thus, the tool contains two movable systems having the ability to radially move to and from the y axis relative to the housing 5. The number of movable systems depends on the number of bars. It can be more than two. The first movable system includes a bar 3, a holder 7, an earring 9, an eye 11, a column 13, a guide 18, a spring 20, a load 16, a spring 24. The second movable system consists of a bar 4, a holder 8, an earring 10, a spring 12, a column 14, rods 19, springs 21, weights 17, springs 25. The amount of weights 16, 17 can be increased by adding weights 26.27 and containers 28, 29 filled with heavy metals. Bars 3, 4 have a working surface 30 and a chord 31.

The processing method in dynamics. Before processing the workpiece 1 is installed in the device, for example, a collet chuck, or a magnetic cartridge with hard

supports conditionally not shown. The tool body 5 is mounted on the spindle 6 of the grinding machine in the same way as installing the faceplate with the grinding wheel. The tool is selected so that the radii of the working surface 30 of the bars 3, 4 in the longitudinal as well as in the transverse direction are equal to the corresponding radii of the work surface 2 of the workpiece 1. Either the working surface 30 is straightened beforehand. For this, the bars 3, 4 are shifted to the axis II to the desired distance and fixed with a stitch, not shown conditionally, and correct them with a diamond roller or diamond pencil, not shown conditionally, Align the rotation axis of the spindle 6 and the tool with the axis H of the machined surface 2 of the preform 1. Then combine the symmetry plane of the working surface 30 of bars 3, 4 with the plane II-II of symmetry machined surface 2 by a longitudinal movement, e.g., a tool with the spindle 6 and the wheelhead (conventionally not shown). Turn on rotation

workpiece 1, then the rotation of the tool bars 3, 4 in the same direction as

the direction of rotation of the workpiece 1. When

. of this, the rotational speeds of the workpiece and tool are selected such that the linear speed V of the bars is in the pre-determined interval Vmin - Vmax, and the linear speed / pre-work is less than V by the value of the selected cutting speed Vp.

So, if the workpiece 1 rotates clockwise with an angular speed of wd, then the tool - bars 3, 4 is also clockwise with an angular speed of Odl. Under the action of centrifugal force bars 3, 4 together

with loads in the composition of the movable systems move towards the axis I-I, until they touch the work surface

2. It is supplied by SOZHD under pressure to the zone

contact of the bars 3, 4 and the work surface 2. On each of the bars 3, 4 (Fig.

3. 4) the following forces apply: FM-I is the weight of the tool system (bars 3, 4, holder 7, 8, etc.); Рm2 is the weight of the weight of the cargo system 15, 16 (cargo 15, 16, cargo 26, 27 , masses 28.29, etc.); Rsch and FU2 are centrifugal forces developed by the tool system and the cargo system, respectively; FI and F2 are the elastic forces of the springs 19. 20 and 23, 24, respectively; F - Rezanich force.

The equilibrium equation of bar 3 or 4 in varies from Fm | n to Fmax. The pressure Q also changes smoothly at any point of contact with the workpiece. With a surface of 2 it looks like this

the value of Fmin from the condition of providing the required F FMI sin (Ai t + Fw2 sin (Ol t -5 of the required material removal per unit time - RC1 + РЦз - FI - Fa. (3) nor, i.e., the required productivity.

This condition defines the minimum possible. The greatest possible linear velocity Vmin (the formula for the cutting force F in the upper position 1) and the corresponding frequency of rotation of the bars (Fig. 3) are obvious. 10 bars of 3.4.

After substituting the components and Fmax FMi + Рм2 + Рц2-Рц1 transformations, the equilibrium equation

-FV-F9Г4У has the form

IJYu- Qmm -S (MM + Mr) -g + (Mr -tail the smallest value is in the lower position - .. D / lg-rrrrr-, - / e ni Mi R1) | -30 | (6)

Fmln.

- FI - F2. (5) where rimin is the minimum acceptable frequency

During each revolution of the bars 3, 4 of the rotation of the tool,

around the workpiece 1, the cutting force F smoothly

p - s about V then -Qmin -s - (mi + mg) -d + FI + TG, 7,

Fri.-jj - Mg G-Mi-Rl (7)

Determine the minimum allowable

linear tool speed Vmm l D nmin, (8)

thirty

/ -part n VlO Qmln S - (MM + Mr) -g + Ti + F2, Q,

vmln - oJ and --------.---- t- -------

 - MM Rl

35

where D is the calculated diameter of the processing-providing high quality surface surface, the boundary layer, characterized by the input designation A 30D; Bmin the absence of burns on the processed

10-Qmin S; B (Mg + Mi) -g; surface 2.

 rPc2-Mi -RC1. receive. 40 The transformed equilibrium equation (4) has the form

Vmln A V bmln + C + -2,.

Г Yu Qmax S - (Мi + Mr) -g + (Mr R2 On the other hand, there should be a limit.. / Ug-Ptakh) 2, 1 The upper linear value is also calculated soon -45 Mn nij l Q I - ri r-2. (1U)

vmax of the tool (see formula 2) and j

the corresponding value of the frequency of rotation - Determine the maximum allowable

puppies Ptah. They are selected from the condition of speed

zoo-otach-z + (Mi + Mg) -d + PT + rT ,,,,

Ptah - -------- Ggo - Ggo - ----. (11) I - Mi-Rl.

and .maximum allowable linear speed-Vmax D- Ptah. (12) Tool height 55

V groin 30 -D ° - ° tzx-ZCh- (Mi + M g) -d + P1 + FT maxMr-R - M "-Ri

(thirteen)

Enter the designation Btah receive

10 Qmax S,

V

max

 L Vbmax - B + Fi + F2 -A ----

 In addition, acceptable values of roughness and waviness must be ensured, which can be counteracted by the occurring self-oscillations. One direction of rotation of the workpiece 1 and the bars 3, 4, as well as the periodicity of the pressure changes of the bars during each revolution ensure the absence of self-oscillations.

The required cutting speed Vp is set and the necessary linear speed Ud of the workpiece is found from the condition

UD UR and workpiece rotation frequency

Vn

(14)

(fifteen)

After the metal removal is completed, for a specified period of time, the rotation of the tool with the bars 3, 4 is turned off, the spindle 6 brakes and stops. The bars 3, 4, under the action of the springs 19, 20 and 23, 24, move away from the work surface 2. In this case, the loads 15, 16 move along the guides 21.22 of the body 5, and the earrings 9, 10 together with the columns 13, 14, which slide in holes 15, 16. Both movable systems depart from axis II. The value of the radial movement of the bars 3, 4 is chosen so as to ensure removal of the workpiece 1 from the device, as well as to compensate for their wear. After stopping the rotation of the workpiece 1, turning off the clamp drive in the tool, the workpiece 1 is removed from the machine. The method allows to process several workpieces simultaneously with several bars.

An example of a specific implementation. It is necessary to process the inner ball bearing ring with the dimensions of the invention. Formula of the invention A method for processing workpiece rotation surfaces, in which abrasive bars are pressed against the workpiece’s work surface and the bars and workpiece are rotated, characterized in that, in order to increase the productivity and quality of processing of the outer surfaces, weights are taken each of which is associated with a corresponding bar,

Washable surface D 55 mm, gutter width L 14 mm. A minimum value of average pressure Qmin of 0.05 kg / cm and a maximum value of Qmax of 0.50 kg / cm2 are chosen. The area S Ы 14 47.63 666.84 mm2 6.67 cm was determined; the mass of the tool system - Mi bars 3.51 kg; weight of the cargo system Mg 2.5 kg; the radii of the centers of mass: RI 75 mm 0,075 m; Ra 102 mm 0.105 m; spring force; FI 53 N, F2 53 H; acceleration of gravity q 9.8 m / s.

Determine the minimum and maximum permissible frequencies and speed of rotation of the tool

rwn -9 55 VM 5T ± bl ± 5r "rim.n -0,2730-0,2625

633 rpm

Ptah

V 33.3 + 59 + 53 -F53

0.0115

5

0

5

0

- 1254 rpm

Vmin 109.3 m / min, Angles 216.5 m / min.

The peripheral speed of the bars U is 200 m / min, and the cutting speed Vp is 120 m / min. Determine the maximum workpiece speed

Beat V-Vp 80 m / min and the required frequency of rotation

Vg 1000 80-1000

PD

 463 rpm

n-D 3.14-55 The actual rotational speed of the workpiece, front 470 rpm and tool pi 1200 rpm, is received on the machine. After processing the surface of the groove of the specified ring, the cut is reduced from 2.5-3.8 microns to 0.3-0.9 microns. The processing method allows in comparison with the prototype method to increase accuracy by 60%, productivity by 40%.

and they are installed on different sides of the workpiece with the possibility of joint movement relative to the latter, the bars are interconnected by elastic elements, the workpiece is rotated in the direction of rotation of the bars, and the speed of rotation of the bars is selected from the condition Vmin V V.min ,,

WHERE AND A .Vbmln -C + r-i -FTT

G

/ l Umax + B + h + h2 vmax A ------- p -------

-V Vg + Vp;

A 30 -D: BTSC 10, CWS;

Bmln Yu Qmax S,

B (Mi + Mg) -g; G MG-R2-MnRi;

p is the calculated diameter of the treated surface;

Qmin is the average value of the minimum pressure force;

Qmax is the average value of the maximum pressure;

Mi is the mass of bars;

Mg is the mass of cargo;

S is the projection area of the bars on the axial plane;

RI is the radius of the center of gravity of the bar;

R2 is the radius of the center of gravity of the goods;

FI and Fa are the elastic forces of elastic elements;

VA is the rotational speed of the part;

Vp is the cutting speed.

Figure 1

& Fie. 1

Editor I. Ivanova

Figure 4

Compiled by B, Prilutsky;

Tehred M. Morgenthal Corrector N. Buchok