RU1773700C - Method of polishing cylindrical holes - Google Patents

Abstract

Usage: for honing long holes with longitudinal grooves (the kit includes several lapping). SUMMARY OF THE INVENTION: The lapping is a rigid body in the grooves of which diamond bars are glued. The housing ends with one or two shanks for mating with the quick change machine chuck. The length of the working part of the lapping is equal to the length of the hole, the length of the inlet part of the lapping is equal to the diameter of the lapping. The diameters of the lapping in the set were experimentally accepted so that the last lapping removes the allowance not exceeding 1/4 of the tolerance for making the hole, in subsequent lapping the removed allowance uniformly increases by 1.5 ... 2 times, but does not exceed 30 ... 40 mm. Between the grinding diameter D, the width of the bar B and the number of rows of bars in the grinding, the dependence D / B is 8 or 6, where 8 is the minimum number of rows of bars on the grinding for a hole with one groove (pcs); 6 is the minimum number of bars of rows on a lapping for a continuous hole (pcs.). 3 ill.

Description

FIELD OF THE INVENTION The invention relates to methods for grinding precision holes in honing machines with a set of grinding tools equipped with diamond bars with high processing quality and high productivity.

Known are the technological processes of honing holes in various parts and lapping or hones for performing such operations (Danilevsky V.V., Engineering Technologies. M: Higher School, 1963, pp. 171-173), which briefly describes the contents of the grinding process and shows the figure a lapping bar with sliding bars for performing this operation.

Such honing heads with sliding bars have been widely used for finishing continuous short holes. In high precision long openings, the length of which is more than 5 hole diameters and the lateral surface of which is cut by a longitudinal groove, such honing heads with sliding bars are inoperative. In the book of Maslovsky V.V. Finishing and lapping work (M ,: Higher school, 1971, pp. 170 ... 171, &3; Lapping for finishing holes; paragraph: fixed lapping, Fig. 81a) shows a hard cast iron lapping for manual finishing of a hole , the length of which can be equal to 5 hole diameters and more and its side surface is cut by a longitudinal groove. OneXJ

with

Xi

Oh Oh

However, such a lapping method and lapping itself are associated with manual labor, which is not the best indicator.

The invention of ed. St. No. 1189666, cl. 24 V 33/02 (Deep Honing Method) stipulates that it is possible to obtain an exact hole when removing allowance up to 0.2 mm with a dimensional diamond scan with an intake cone under certain processing conditions. However, in case parts on honing machines, such a reaming cannot be used to treat the hole.

The aim of the invention was to improve the accuracy of lapping during the processing of long holes with a longitudinal groove.

This goal was achieved by the fact that in a hard lapping machine equipped with diamond bars, the minimum number of rows of bars was experimentally established - 8 pcs., In which the lapping stably grinds the hole and experimentally worked out the method of processing the hole with a set of lapping blocks, in which the first lapping in the set the diameter is equal to the diameter of the hole, the diameter of the second lapping in the set is increased by the size of the removed allowance, which this lapping is able to process (for example, for 0 55 mm 30 ... 40 μm), and all subsequent ones when diameters the diameters gradually increase, and the allowance removed by them uniformly decreases by 1.5 ... 2 times in comparison with the previous one.

In FIG. 1 shows lapping with one shank; in FIG. 1 - lapping with two shanks; in FIG. 3 is a section AA in FIG. 1,

The set of hard lapping includes several lapping, in which the lapping (Fig. 1 and 2) contains a rigid casing 1 with grooves, where the diamond bars 2, glued with glue of the type Moment (TU 6-15-1268-80), are located. Housing 1 ends with a square shank and a hole for fastening in the quick change chuck of the honingopal machine. The length of the working part of the lapping is equal to the length of the lapping hole, the length of the inlet part of the lapping is equal to the diameter of the lapping.

Experimentally established the minimum number of rows of bars on lapping, which is related to the width of the used bars by the dependence

S.

where D is the outer diameter of lapping, mm;

In - the width of the bar on grinding, mm;

8 - the minimum number of rows of bars on the lapping, at which it works stably (in pcs.). Number of rows of bars

on lapping technologically more acceptable multiple of two.

The diameters of the ground in the set were adopted as follows. The first grinding in

5 the diameter is equal to the diameter of the hole, the second lapping is increased in diameter by the amount of the removed allowance, which, at a specific lapping size, is able to be removed in processing (for example, for diameter f 55

0 mm - 30 ... 40 microns), in subsequent lapping, their diameters gradually increase, and the allowance removed by them uniformly decreases by 1.5 ... 2 times compared to the previous one.

5 The starting diameters DI on the first lapping are underestimated in comparison with the lapping diameter D to allow free installation of the lapping in the hole and its direction during reciprocating

0 movement (for example, for diameter 0 55 - (D-Di) 10 .., 25 microns), in subsequent lapping, DI is equal to the diameter of the previous lapping. Departure of the bar 2 over the body of the housing 1 is 0.1 ... 0.3 mm.

5Work with a set of hard laps on

a honing machine is produced directly. The part is fixed with the machined hole in the axis of rotation of the machine spindle, the first

0 lapping into the hole, connecting the lapping shank with the spindle driver chuck, setting the lapping overrun, the number of revolutions and the number of double lapping strokes, fed into the processing zone of kerosene, include

5 machine and grinding occurs. Lapping is then successively replaced, increasing the diameter to a size and obtaining the desired hole quality. Lapping with two shanks, FIG. 2, it is possible to achieve the best results in reducing the taper of the hole.

An example of the use of the PS-218G lapping kit at the Glukhovsky plant of aggregate units of the Ministry of Industry and Industry and the processing method

5 holes in the housing of the power head 1UH4035.124. The diameter of the hole in the housing is 0 55 mm, its length is 271 mm, the hole is cut by a side groove 25 mm wide. It is necessary to get the deviation of the hole from

0 cylindricity up to 6 microns and ensure that the axis of the hole and groove is 20 microns parallel.

The technological process involves before grinding the hole 055 with a set of priming PS-218G groove 25 mm, cut 23 mm in advance into the passage into the hole 055 mm. The first grinding in with a diameter of 0 54.95 mm results in the stripping of the hole and correction of its axis (diameter of the hole before grinding Φ 54.95N9 mm).

Lapping No. 2 has a diameter of 54.985 mm, they are given cylindricality in the hole with an accuracy of 8 μm, and the hole cleanliness is improved to the seventh grade (1.25). Then, a groove of 2.5H9 is milled coaxially with the hole 54.985 in moderation. By grinding fsfe 3 with a diameter of f 55.015 mm, the curvature of the hole after milling is corrected. Lapping No. 4 with a diameter of Ј 55.035 mm improves the geometry of the hole. Lapping No. 5 0 55.045 mm improve the hole geometry and surface roughness to 0.32. By lapping N2 6055.050 mm, the hole $ 55 mm is finally brought to a cylindrical deviation of not more than 6 microns. A mandrel of 55 mm with a gap of 3 μm should, from the effort of the hand, go through the hole in the passage,

Claims (1)

SUMMARY OF THE INVENTION A method of grinding in cylindrical holes, in which the grinding is introduced into the hole to be machined and imparted to it rotational and reciprocating movements, characterized in that, in order to increase the grinding accuracy when machining long holes with a longitudinal groove, an additional nth amount is taken hard lapping, while taking the diameter of the first lapping equal to the diameter of the hole to be machined, and the diameter of the second lapping - large diameter holes by 30% of the size of the allowance, and the diameters of the other lapping sheets are taken from the condition of removing the allowance by them, 1.5-2.0 times smaller than the previous one. Lapping allowance No. 3 is enlarged to remove traces of a boring tool.  TO t Figure 2 Figz