SU1092004A1 - Powder pressing device - Google Patents

Description

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The invention relates to powder metallurgy, in particular, to devices for pressing powder used in the manufacture of long pressed pieces.

A device for pressing powders is known, including a die, a central rod, a base, side punches installed with the possibility of radial movement from the axis of the matrix axis and a wedge SP. The disadvantages of this mold are low productivity and quality of pressed blanks, due to the need for full development and assembly of the device after each pressing cycle and partial destruction of the blanks on the edges of the wedges. The closest to the proposed technical essence and the achieved result is a device for pressing powder, containing working and ejecting punches installed in a die and a hydraulic cylinder with a piston, the working one being the top one and pushing the lower punch E 21 at the same time. the performance of the process and the quality of the compression of long workpieces, due to the uneven density distribution along their height. The purpose of the invention is to increase the productivity of the process and the quality of the pressed blanks. This goal is achieved by the fact that the device for pressing the powder, which contains working and ejecting punches installed in the matrix and a hydraulic cylinder with a piston, is equipped with an axial force conversion mechanism in the radial, located in the matrix, and a pressure redistribution mechanism installed in the form of a wedge and installed between the matrix and the hydraulic cylinder; in this case, the guides are made in the matrix and the hydraulic cylinder, and the wedge is installed with the ability to interact with its working surfaces with the guides. FIG. 1 schematically shows the proposed device, the initial position; in fig. 2 is a section A-A in FIG. one; in fig. 3 is a section BB in FIG. one; on league. 4 shows a section B-B in FIG. 3; in fig. 5 - section GG on

Fig, 1; in fig. 6 - device at the time of extrusion of the compacted billet.

The device consists of a hydroshshindra 1 with a spring-loaded spring 2 piston 3, in which there is a cavity 4, where a piston 6 is placed spring-loaded by a spring 5, connected 7 with an ejector pugson 8 entering into the matrix 9, inside which is placed a central rod fixed in hydroceletes re 1 10, springs 1 {, which enclose an ejector punch 8, spring-loaded springs 12 pistons 13 with hydraulic cylinders 14, in which there are cavities 15 with limiters 16 strokes and spring-loaded springs 17 pistons 18 associated with working punches 19. Except for o, between the matrix 9 and the hydraulic cylinder I with the piston 3 there is a wedge 22 installed in the direction of the 20 and 21 with the axis 23 fixed in it, on which the washer 24 is located, spring-loaded spring 25 to the bracket 26 fixed on the matrix 9. The latter is closed by the cover 27 associated with the pins 28 with the ejector punch 8. At the same time, in the cover 27 there is a window 29 closed by the plate 30, and it itself is spring-loaded to the matrix 9 by the spring 31. The pistons 13 are connected to each other by a ring 32. The pistons 13 and 18, hydraulic cylinder 14 with cavity 15 is a mechanism that transforms The axial pressing force into the radial, and the wedge 22 installed in the guides 20 and 21 with the axis 23 fixed on it, on which the lash 24 is located, spring-loaded 25 by spring to the bracket 26 fixed on the matrix 9, is a pressure redistribution mechanism. The device works as follows. In the loading cavity And the matrix 9 through the window 29 (Fig. 1 and 2) 31 pour the mixture. Then the window 29 is closed with a strap 30. By the case of the 32 devices with-. put pressure, which is transmitted through the pistons 13 to the working fluid of the hydraulic cylinder 14. As the pressure increases, the working fluid moves the pistons 18 and the working punches 19 associated with them, the course of which is limited by the limiters 16. Thus, pressing occurs. With a further increase in pressure, they begin to move along the guides 20 and 21 of the wedge 22 (Fig. 3 and 4), due to the fact that the wedge angle exceeds the self-braking angle and at a certain pressing force P, the force P (Fig. 4) begins to exceed the total force the spring and the force of the spring 25 when working deformation. Moving the wedge 22 redistributes the pressing force from the hydraulic cylinder 1 to the piston 3 (Fig. 6). The latter (fig. &Amp;) begins to move downward, compressing the working fluid entering the hydraulic cylinder I. TfnAtas & fb transfers the force to piston 6, 4 Tut in the CBOt queue through rod 7 - to the piston 8, which is connected 1 & tf 28 with a lid 27. Thus, when the ejector punch 8 is moved, the flap 27 is raised, and the pressed billet is pushed out of the matrix 9. After the pressure has been released. all elements of the press-and-press device are returned to the initial state by the action of the springs 12, G /, 11, 5 to 2 compression. The wedge angle must exceed the braking angle by an amount equal to arcsin -i, where P is the force required to compress the product; F - sutarnna spring force during working deformation; f is the coefficient of friction. For example, when pressing carbide long, thin-walled bushings with an external diameter of 30 mm, a hole diameter of 25 mm and a height of 60 mm, the required pressing force of 4 is 28 tons. At a coefficient value of friction equal to 0, 2 and spring force 200 kg, the angle of the wedge should exceed the angle of self-braking by an amount equal to l rt arcsin. Л .... "arcsin 0,00 2SO 25. If this condition is not met, then the wedge will not be able to move along directions 20 and 21, redistributing the pressing force, since the force P will be less than the total force FTP + F. The application of the proposed device allows improving the quality of pressed blanks. So, when pressing blanks from hard-alloy mixtures, such as VN20G2, the discrepancy in density along the height of the pressed blanks does not exceed 5%, while when using the known device, the discrepancy in density reaches 40%. The productivity of the technological process using the proposed device increases by more than 40% (the duration of the pressing and extraction of the workpiece in the proposed device is 5.5 minutes, while in the known device, these operations take 8 minutes). Thus, the use of the proposed device allows to increase the productivity of the process and the quality of the pressed blanks.

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Claims (1)

'DEVICE FOR PRESSING POWDER, containing working and pushing pu installed in the matrix! Ansons and a hydraulic cylinder with a piston, which is related to the fact that, I, in order to increase the productivity of the technological process and the quality of pressed blanks, it is equipped with an axial conversion mechanism. effort in radial arranged in a matrix, and a pressure redistribution mechanism made in the form of a wedge and mounted between the matrix and gtsdrotsilindrom while in the matrix, and the hydraulic cylinder are made conductive napravlyayu- _β and the wedge is installed with the possibility of interaction with their working surfaces with guides.