RU2450878C2 - Method of producing auger - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: proposed method comprises making flat work pieces, jointing them together rigidly and stretching uniformly produced semi-finished auger along lengthwise axis. Said work pieces are made from isosceles-trapezoid-shaped plates rigidly jointed together on sides to form open-end washer in the form of right polygon.

EFFECT: lower metal input.

1 dwg

Description

The invention relates to mechanical engineering and relates to a method for manufacturing products with helical ribs, in particular spirals for screws.

Known methods for producing spirals for screws, including cutting a workpiece in the form of a metal strip of rectangular cross section and its subsequent deformation into a spiral by rolling in special rolls (see, for example, copyright certificate No. 671899, IPC ² B21D 11/06, publ. 05.07.1979; No. 1696072, IPC ⁵ V21N 3/12, publ. 12/07/1991; 1754273, IPC ⁵ B21D 11/06, publ. 15.03.1992).

The disadvantages of the known methods are their high complexity, the need to use for the manufacture of spirals of complex and expensive equipment, energy consumption of production.

A known method of manufacturing a helicoidal screw, according to which annular blanks are cut from a sheet of source material, in each of which a radial cut is made, along the cut lines of the ring are successively rigidly connected to each other, after which they are formed from the obtained semifinished product by uniformly stretching it along the longitudinal axis along the longitudinal axis a spiral that is welded to the shaft (see patent No. 2287391, IPC VC 37/26, publ. 10.01.2006).

The disadvantage of this method, due to the irrational use of the starting material, is the high material consumption of the final product - the spiral, as part of the material cut from the central region of the workpiece is not used in the future and goes to waste. Depending on the size of the screw, the waste can make up 30-50% of the starting material. Given that spirals for screws are made, as a rule, from expensive materials (stainless steel, non-ferrous metals, etc.), such significant losses of material increase the cost of the final product very significantly.

The objective of the invention is to reduce the consumption of materials and, as a consequence, reduce the cost of the product.

The result of the invention is the low material consumption of the screw spiral.

The result of the invention is achieved due to the fact that in the method of manufacturing a spiral of a screw, including the manufacture of flat billets, their rigid connection between themselves and the subsequent uniform stretching of the resulting semi-finished spiral along the longitudinal axis with the given step, the billets are made of plates made in the form of isosceles trapezoid by rigid connections between each other on the sides with the formation of an open washer with contours in the form of regular polygons.

The dimensions and number of trapezoidal plates are determined by the specified parameters of the screw spiral, while the minimum number of plates required for the manufacture of one workpiece is at least three.

If necessary, the contours of the polygons of the preform thus obtained can be rounded to form a ring, the diameter of the outer circle of which is equal to the diameter of the circle inscribed in the outer polygon of the washer, and the diameter of the inner circle, respectively, the diameter of the circle described about the inner polygon.

Figure 1 shows the sequence of operations for the manufacture of the workpiece.

Trapezoidal plates 2 are cut out of the strip of the starting material 1. The required dimensions (height, base length and angle of inclination of the sides of the trapezoid) and the number of plates are preliminarily calculated based on the given design parameters of the screw spiral. Of the plates 2, a polygonal washer 3 is made, after which the plates are welded together at the joints of the sides 4, leaving one of the joints open. Then, from a set of obtained blanks, a semi-finished screw spiral is made up.

In the proposed method, material savings are due to the fact that, in contrast to the prototype, when cutting trapezoidal plates, the starting material is used almost completely, and the losses that occur when turning the blank contours to a ring (if necessary) are significantly less than the losses that take place when cutting ring sheets directly from the sheet.

It should be noted that material losses sharply decrease as the number of sides of the polygon selected as the basis for the workpiece increases, however, labor costs for manufacturing the latter increase. In practice, this contradiction is usually resolved by a reasonable compromise, taking into account the design features and purpose of a particular product.

An example of the practical implementation of the proposed method.

It is required to make a spiral welded to the inner surface of a pipe with a diameter of 600 mm, the height of the turns of the spiral is 150 mm.

By calculation, determine:

- taking into account the deformation of the turns when they are bent, the necessary strip width is 160 mm;

- as a basis for the workpiece, a 24-gon is selected, for which the diameter of the inscribed circle is 600 mm;

- the required angle at the base of the trapezoidal plates is 7.5 °;

- the length of the larger base of the trapezoid is 78 mm;

- the length of the smaller base of the trapezoid is 57 mm;

- the diameter of the circle described near the inner 24-gon - 438 mm,

After performing the necessary calculations, the strip of the original sheet material with a width of 160 mm is cut into trapezoidal plates of the above sizes, they are 24 squares, the plates are welded together on the sides of the trapezoid, and then the contours of the resulting polygonal washer are machined: the outer one to a circle with a diameter of 600 mm, inner - to a circle with a diameter of 438 mm, a radial cut is made in the obtained annular blank, after which a spiral is made from a set of blanks and formed.

For the above example, in the manufacture of spiral blanks in a known manner, the material loss would be about 53%, while when using the proposed method, the loss does not exceed 2%.

Thus, the proposed method provides a significant reduction in the material consumption of the screw spiral and, as a result, saves valuable production materials, reduces waste and reduces the cost of the product.

Claims (1)

A method of manufacturing a spiral for a screw, including the manufacture of flat blanks, their rigid connection with each other and the subsequent uniform stretching of the resulting semi-finished spiral along the longitudinal axis, characterized in that the blanks are made of isosceles trapezoidal plates by rigidly connecting them along the sides sides with the formation of an open washer with a contour in the form of a regular polygon.