SU593840A2 - Disc blade - Google Patents

Description

one

The invention relates to the processing of metals by pressure, in particular to tools of cutting devices.

Known circular knife for waste-free, cutting of the workpiece, the wedge sharpening of the working setting of which is made double with a large ANGLE of inclination at the top.

However, knife durability, especially when cutting high-strength materials, is low,

In order to increase the durability, the top of the corner is made radially rounded.

Fig, 1 shows a knife, a general view; Fig. 2 shows a knife with different twist radii (in Fig. 3 a knife included in the workpiece; Fig. 4 is a graph of the radius of the insertion force (force of radial feed).

The disk knife is made with double sharpening with Li angles, and the ot at the knife tip ot is greater than the angle i. The top of the corner is rounded off by pawiycy t, the size of which is chosen depending on the size and mechanical properties of the cut material.

An increase in the radius T of the tip of the working part of a disk knife, according to the well-known theory of Hertz contact stresses, reduces the internal stresses that occur when a disk knife is in place at the point of contact with the cut pipe, and thereby increases its durability.

The penetration force of the knife into the material is calculated by the formula

p a 0.6 q, b D 9 G aa COS GS1)

where d, is the average specific pressure in the contact zone, equal to Q, in the body of the circular knife; 5 - the width of the contact zone can be

taken to be 21 {Dg is the diameter of the disk knife; girth angle, Tf ,. utop, determined the multiple points of contact of the cutting edge, with the body of the pipe being cut;

Y is the angle of friction, determined from the appearance of f,

Claims (1)

where -f is the coefficients of the alarm,: For example, we will accept the evaluation scores - 1, the knife does not slip when the COS U pipe is rolled around, 0.707. The wrap angle is derived from 2W uS -t- 2 CASJ) 2-. coslT-l- -t W-TZa l 2BauS rfleuS - feed per revolution of the knife around the pipe being cut; DT is the outer diameter of the pipe. Average stress О, cf. by the deformation area from (1) is d g pi o, 66Dair a3 osr With a radius of curvature of 0.25 mm, 0.5 mm, 0.75 MMj & fp, respectively, R & Io 725 kg / mm, 385 kg / mm, 37O kg / mm. Knives 6 are made of steel bHbVZMFE according to GOST 5950-73, which, according to measurement data, does not exceed 430 kg / mm when hardened, the size of the magnifying glass is 430 kg / mm. Therefore, it is advisable to use for cutting disc knife with a radius of rounding at the top of it not less than 0.5 mm. It has been proven by practice that knives used in these conditions of work with a radius of 0.25 mm, when carrying out a test of durability of BecbNta, quickly went out of order (about 350 cuts), while the sheath, for example, with a radius of 0 75 mm increase the number of pe.3DB to 100O. Therefore, the values of rounding radii in each specific case can be calculated depending on the mechanical properties of the material being processed. Formula of invention Disc knife according to the author. St. No. 187484, characterized in that, in order to increase durability, the apex of the corner is made rounded in a radius. J3 Fi9.1 w " Fig: 5