SU941751A1 - Brake disk manufacturing method - Google Patents

Description

(54) METHOD OF MANUFACTURING BRAKE DISCS

The invention relates to mechanical engineering, primarily transport, and can be used in the manufacture of steel friction disks used in friction devices - brakes, gearbox control elements, clutches, rotation mechanisms. A known method of manufacturing friction discs includes thermal and mechanical processing. The friction disc blanks are made by cold forming from sheet material. Heat treatment of blanks consists of quenching and high tempering, mechanically - from turning and gear milling operations, followed by grinding the surfaces. The removal of grinding stresses is carried out by heat-setting (thermal correction) 1. However, the known manufacturing method does not allow to obtain friction discs that are resistant to distortion from thermal stresses arising during their operation. It is often not possible to increase resistance against warping by changing the geometric dimensions (for example, increasing stiffness by increasing the thickness of the disk) according to overall conditions. Distortion axisymmetric ("padded," umbrella) and axially ("wavy) is possible. More often, axisymmetric warping occurs. A prerequisite for its occurrence is the presence of compressive stresses concentrated at the inner radius of the disk blade and stretching at the outer. Pel of the invention is the reduction of the disc warpage during operation. This goal is achieved by the fact that according to the method of manufacturing brake discs, including thermal and mechanical processing with subsequent heat setting, after heat setting at a distance of 0.2 times the width of the brake disc web from its outer edge, plastic deformation is performed on the end surfaces of the brake disc the formation of an annular groove with a depth of 4-6% of the thickness of the brake disc and a width of 15-20% of the width of the brake disc. As a result of plastic deformation after knurling, preliminary stresses occur in the dtsk web, which are opposite to the sign of the thermal stresses that occur during operation. FIG. Figure 1 shows the friction disk with an indication of the location of the knurling site (RH, RB, RC are the outer, inner and middle radii of the friction surface, respectively; g, g, d are the outer, inner and average radii, respectively, part of the surface of the disc subjected to the knurling operation; C is the thickness disc; c — plastic deformation depth as a result of knurling); in fig. 2 is a plot of the preliminary stresses of gp resulting from the knurling of a part of the friction surface in the zone between the outer and the average radii of the disk; in fig. 3 - thermal stresses arising and accumulating in the disk during its operation; in fig. 4 is a plot of actual stresses 6f resulting from the joint action of the preliminary stresses obtained during knurling and thermal stresses arising during operation. Since the preliminary stresses resulting from the knurling of a part of the friction surface in the zone between the outer and middle radii of the disk are opposite in sign to the thermal stresses arising during operation, the actual stresses are always reduced by the amount. . The magnitude of the warp from thermal stresses is substantially reduced.

We offer you to make friction discs from ZOHTSA steel. Geometric

20

15

optimal knurling parameters (software width and location of the knurled area).

In order to obtain comparative data, parallel tests were carried out on a disk made according to known technology (disk 3). All dtskov controlled the deviation from the flat form.

1/3

0.66

1/5

Claims (1)

0.08 sizes of disks, mm; outer radius 250; inner radius 225; thickness 4. As a result of calculating the values of stresses arising during plastic deformation of a part of the friction surface, during knurling, and the values of possible circumferential stresses arising during exploitation, determine the place and size of the knurling zone, as well as the required deformation depth. The following knurling parameters, optimal for the given construction and material, have been established: both surfaces are rubbed near their outer radius; the width of the knurled part of the friction surface is 15-20% of the width of the blade; the average radius of the knurled part of the friction surface is removed from the outer radius of the disc by 1/5 of the width of the blade; the plastic deformation depth during knurling is 4-6% of the disk thickness. The table shows the test results. The disks 1 and 2 were made in accordance with the proposed method, from which disk 2 was made in full accordance with the obtained optimal parameters for this design implementation, and disk 1 had a deviation from the table. manufactured by the proposed method, significantly less than the disc made by known technology. The proposed method of manufacturing friction disks will significantly reduce the probability of jamming of friction devices due to warping of friction disks li, thereby increasing their reliability and durability of work. The invention The method of manufacturing brake discs, including mechanical processing and heat, followed by heat setting. characterized in that, in order to reduce disc warping during operation, after heat-setting at a distance of 0.2 the width of the brake disc web from its outer edge, plastic deformation is performed on the end surfaces of the brake disc with the formation of an annular canye of depth 4-6 ° / thickness. : The disk and PCF 15-20 / o from the width of the brake disk. Sources of information taken into account in the examination 1. .L. W. et al. Frictional mechanisms with sulfocyanine friction bunkers. L., “Maschinostroenie. 1972. with. 146 (irotype).