SU1227365A1 - Method of working holes - Google Patents

Description

The invention relates to the processing of metals by cutting and can be used in the processing of holes located in hard-to-reach places in separately machined parts intended for fitting.

The purpose of the invention is the expansion of technological capabilities by processing holes in hard-to-reach places.

FIG. 1 shows the position of the holes located in hard-to-reach places relative to the contour of the part; in fig. 2 is a view A of FIG. one; in fig. 3 - nominal and maximum permissible positions of the axes of the openings of the mating parts relative to their contour; in fig. 4 is a diagram of the position of the hole in an inaccessible place; in fig. 5 is a diagram of a hole with a new position of the axis.

In part 1, holes 2–5 located in hard-to-reach places and intended to mate with holes B-9 in parts 10–13 are to be machined. Nominal positions of any matching holes, for example 2 and 6, coincide and are expressed by common the line О-О, which relative to the contour of the part 1 is located in such a way that it passes through the part, in connection with which the tool access to the hole 2 is difficult. In part 1, the axes of holes 2 and 4 are located in the W-W plane passing through the design base (part axis) MP, and the axes of the holes 3 and 5 are in the T-T plane also passing through MP. The W-W and T-Twa-intersect planes, in this case at a right angle.

The limiting positions of the O-O axis with positive and negative tolerance values of the B position of the O-O axis relative to the design base — the MP lines — are indicated by the DE and FN lines, respectively. In the DFNE figure, the D, F, N, E points are boundary, defining the maximum allowable positions of the O-O axis relative to the contour of parts 1 and AO.

Collectability of parts is ensured when passing the OO axis of the mating holes 2 and 6 within the figure, as in the case of passing the OO axis parallel to the design basis MP, for example, in detail 1, the OO axis is at the limit of negative linear tolerance - the FN line, and in part 10 - at the limit of the positive tolerance value - the DE line, as well as the arbitrary position of the O – O axis within the DFNE figure, for example, the O – O axis may extend at an angle to the MP line. The cases of limiting location of axis О-О ensuring the collection of parts may be as follows: axis О-О passes through the boundary points FE and DN at an angle

about

five

50

0

± a and the initially specified position and to the line mr.

Due to the fact that the nominal and limiting positions of the axis O-O, which are parallel to the design base of the MP, do not provide access for the tool to the place of machining the hole, the simplest technical solution is to obtain a new position of the axis O-O, for example FE, providing free access of the tool to the machining site within the figure.

For this, the axis of rotation of the tool 14 is positioned relative to the initially set position of the axis O-O at an angle a in the plane passing through the DE and FN lines of the maximum allowable position of the axis O-O such that when machining the hole in the first part, the tool axis through point F - the point of intersection of the line FN, which determines the maximum permissible negative position of the axis O – O of the hole 2 with the surface of the workpiece 1 that is not adjacent to the associated part 10.

When machining the hole 6 in the part 10, the axis of the tool 14 and the initially specified position of the axis O-, O are mutually positioned at an angle a, and the tool axis passes through the point E - the intersection point of the DE line defining the positive maximum allowable position of the axis of the hole 6 s the surface of the part 10, not adjacent to the mating part.

In the W-W plane, the EF- line, which is the new position of the axis of the hole 2, and the QR line, which is the new position of the axis of the hole 4, intersects at the point V, where the starting point is the tool tip.

Parts 1 report the rotation in the W-W plane at an angle - | -os, the tool axis coincides with the EE line, and the tool is informed with the rotation and movement S, which provides the opening 2 in the part 1 with the new position of the EE axis. Parts 1 then report a rotation in the WW plane at an angle of -os with respect to the axis of the MR, while the axis of the tool 14 is aligned with the QR line of the new position of the axis of the hole 4 in the part 1, and the tool is informed of the rotation and linear movement along QR, which provides the hole 4. With This allows the tool to freely access holes 2 and 4.

When machining the holes 3 and 5, equally spaced about the axis of the MP in the T-T plane, the parts 1 sequentially report a rotation through an angle of ± a in the T-T plane. Tool movements are similar to those indicated.

To derive the calculated dependencies, use the scheme in FIG. 3

The angle a is determined, for example, from the triangle EFN,

, En

tg ° FN

EN a arctgp |;

Since it is the tolerance of the position of the О-О axis of the holes 2 and b, and FN EL + + LN, where is the depth of the hole 2 in the part 1,

LN h2 is the depth of hole 6 in part 10, we get

a arct prr-htg hi + h2

Example. Thin-walled cylindrical part 1 has two annular flanges 15 and 16 with a diameter of mm and a thickness of mm at the ends and one ring-shaped stiffening rib 17 with a thickness hi of 10 mm inside the part, located at a distance I from one of the ends of the part. Four holes 2–5 mm in diameter must be made in the stiffening rib 17, the O – O axes of each of which are parallel to the design base MP, for fastening the mating brackets 10–13, each of which also has a hole 6–9 with diameter d and depth mm. Holes 2-5 are located on a diameter of mm through 90 ° with a tolerance of ± 0.3 mm relative to the base MP.

Due to the fact that the internal diameter DI of the flanges 15 and 16 is smaller than the diameter Dj of the location of the holes 2-5, i.e. the axis O-O passes through the body of the flanges, free access of the tool to the holes is difficult.

The simplest technical solution is to obtain a new position of the axis of each of the holes, for example, EF, within the linear tolerance b, which allows the tool to freely access the holes in part 1 and collect parts. The new position is achieved by positioning the axes of the holes 2-5 at an angle a

relatively the original O-O position, the value of which is determined by the expression;

"A -ctg | :.

Based on the numerical value of the parameters, it is determined

ten

angle

a arctg -§ 5 2 ° 20.

0

five

five

0

The holes 2 and 4 in the part 1 are machined by the tool 14 on a radial drilling machine using a special oscillating tool 18 and a conductor 19. In the tool 19 for the tool 14, the guide hole 20 is made at an angle a. The jig 19 is mounted on the surface 21 of the stiffening ribs 17 before machining, is aligned with the design base MP and is fixed.

Parts in the plane W-W, passing through the axes of the holes 2 and 4, impart a rotation through the angle + a 2 ° 20. The tool is informed about the rotation and is introduced into the conductor hole 20, then the working feed S is informed before the drill tip is made of metal stiffening ribs 17, resulting in a hole 2 with a new axis position. Similarly, holes 3 and 5 are machined by turning the part through an angle of ± a in the T-T plane intersecting the W-W plane at an angle equal to the angle of the mutual arrangement of the holes (in this case at a right angle).

The holes 6–9 with the new position of the axis in the matched parts are machined separately using a similar conductor using the indicated techniques.

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b

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VNIIPI Order 1990Л2 Ти.раж 1001 Subscription Branch PPP "Patent, Project, 4

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Claims (1)

METHOD OF TREATING HOLES in parts to be subsequently mated, to which the tool is informed of rotation and axial movement, and for each part, a rotation, characterized in that, in order to expand technological capabilities by processing holes in hard-to-reach places, the rotation is carried out in a plane passing through the axis of the part and the axis of the hole being machined, by an angle determined by the dependence: where a is the angle of rotation; δ is the tolerance of the location of the axis of the hole; hi — hole depth in one mating part; h ₂ —the depth of the hole in another mating part. (L fyg. 1 1227365 A1