Process for the manufacture of thin-walled elastoporous parts in the form of bushings in metal-rubber (MR)

Abstract

A process for the manufacture of thin-walled elasto-porous elements in the form of bushings in metal-rubber material (MR), comprises the steps of: obtaining wire fragments in the form of spirals having a lead equal to the spiral diameter, forming a flat blank from said spiral segments; pressing the blank into a roll; placing the roll into a mold; placing some elastic medium inside said roll; and pressing the roll in several passes by axial compression together with the elastic medium elements transforming the axial compression into radial pressure on the roll to be compressed.

Claims

1. A process for the manufacture of thin-walled elastoporous elements in the form of bushings in metal-rubber material (MR), comprising the following steps: obtaining wire fragments comprised of a wire material having a wire cross-section, in the form of spiral segments; forming a flat blank from said spiral segments; pressing the flat blank in a direction perpendicular to a blank plane, wherein an average density value .sub.3 of the flat blank is adjusted depending on a spiral outer diameter d.sub.1, on a diameter d of the wire cross-section, and on the density of the wire material, linked by the following relationship .sub.3=(2.02.8)B.sub.1, where $B_1={\left(\frac{d}{d_1}\right)}^2,$ wherein an average density value .sub. of the compressed flat blank is determined by the following relationship .sub.=(1.52.0)B.sub.2, where $B_2={\left(\frac{d}{d_1}\right)}^{1.5},$ wherein the flat blank is formed with a length that is 7 to 15 times the average of an outer diameter D.sub.O and of an internal diameter D.sub.I of the finished bushing, with a width greater than a height H.sub.C of the finished bushing, but less than a value $H_C\frac{{}_C}{{}_{}},$ where .sub.C is an average density of the MR material in the finished bushing, winding the pressed flat blank at least in 3 layers on an elastomer cylinder with such a tension that ensures an outer diameter of a roll obtained is equal to the diameter D.sub.O, wherein an elastomer cylinder height is greater than a width of the compressed flat blank, wherein an elastomer cylinder diameter is less than the diameter D.sub.I, placing the roll into a mold providing the manufacture of a bushing blank with its average density greater than that of the compressed flat blank by 1.3 to 2.2 times, with an internal diameter D.sub.I and with a wall thickness less than 0.14 D.sub.O, wherein the final pass of the bushing blank pressing is carried out to the value of average density .sub.C greater than .sub., but less than 0.8; placing elastic elements inside said roll; pressing the roll in several passes by axial compression together with the elastic elements transforming the axial compression into radial pressure on the roll to be compressed.

2. The process of claim 1, wherein the bushing blank is additionally provided, on both ends, with perforated annular shells with a U-shaped meridian section, and the final pressing pass of the bushing blank is carried out in a metal mold without elastomers, with simultaneous deepening the ends of the bushing blank into the perforated annular shells with the U-shaped meridian section.

3. The process of claim 1, wherein in the process of pressing the flat blank, the flat blank is placed with flat surfaces against elastic sheets.

4. The process of claim 1, wherein the flat blank is pressed by rolling between cylindrical rollers with elastic coating.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The essence of the technical solution according to the present invention, as an embodiment version, is illustrated by drawings.

(2) FIG. 1 shows a flat blank placed between two elastic plates.

(3) FIG. 2 shows a flat blank while compressed between cylindrical rollers with an elastic coating.

(4) FIG. 3 shows a pressed flat blank wound on an elastomer cylinder with some tension.

(5) FIG. 4 shows a mold in the process of a radial-axial pressing.

(6) FIG. 5 shows a mold at the final pass of the bushing blank pressing.

(7) FIG. 6 shows a mold at the final pass of the bushing blank pressing together with perforated annular shells having a U-shaped meridian section.

(8) FIG. 7 shows a finished elastoporous part in the form of a bushing.

(9) FIG. 8 shows a finished elastoporous part in the form of a bushing with perforated annular shells embedded on their ends and having a U-shaped meridian section.

DETAILED DESCRIPTION

(10) As starting material for the manufacture of thin-walled elastoporous parts in the MR material with the application of the process of the present invention, fragments of a metal wire spiral having a lead equal to the spiral diameter are used, said spiral fragments being used to mold a flat rectangular blank.

(11) The value of average density .sub.3 for the flat blank is selected depending on the outer diameter d.sub.1 of the spiral, on the diameter d of the wire cross-section and on the density of the wire material, that are bound by the following relation .sub.3=(2.02.8)B.sub.1, where

(12) $B_1={\left(\frac{d}{d_1}\right)}^2.$

(13) After that, the flat blank is compressed in the direction perpendicular to the blank plane to get the average density value .sub.=(1.52.0)B.sub.2, where

(14) $B_2={\left(\frac{d}{d_1}\right)}^{1.5}.$
Said pressing provides a more uniform structure of the MR material in the radial direction. In so doing, the relations given above for the densities enable to develop efficient technological processes for the manufacture of elastoporous parts in the form of bushings.

(15) During the pressing procedure, to provide a uniform distribution of the pressure on the flat blank 1 (FIG. 1), the last is placed with its whole length between two sheets 2 of elastic material (polyurethane, rubber, etc.). In another embodiment (FIG. 2), the flat blank 1 is pressed by rolling between cylindrical rollers 3 with an elastic coating (polyurethane, rubber, etc.).

(16) The length of a flat blank is taken 7-15 times the average value of the outer diameter D.sub.O and the inner diameter D.sub.I of the finished bushing, the width of the same being greater than the height H.sub.C of the finished bushing but less than the value

(17) $H_C\frac{{}_C}{{}_{}},$
where .sub.C is the average density of the MR material in the finished bushing.

(18) The pressing procedure finished, the flat blank 4 (FIG. 4) is wound in at least 3 layers onto an elastomer cylinder 5 with some tension, which provides for obtaining the outer diameter of the prepared composition equal to the diameter D.sub.O.

(19) The height of the elastomer cylinder is taken greater than the width of the compressed flat blank, and the diameter of the elastomer cylinder is less than the diameter D.sub.O.

(20) The composition comprised of the compressed flat blank 4 (FIG. 4) wound onto the elastomer cylinder 5 is placed into a mold sleeve 6 between cylindrical punches 7 having continuous ends.

(21) During the next pass, radial pressing is carried out to give a bushing blank with the average density 1.3-2.2 times greater than that of a compressed flat blank, and with the inner diameter D.sub.I.

(22) After pressing, the punches 7 and the elastomer cylinder 5 are removed from the mold sleeve 6. Through the obtained opening in the bushing blank 8 (FIG. 5), a metal rod 9 with the outer diameter D.sub.O is passed. After that, punches 10 with annular working surfaces are placed and the final axial pressing of the bushing blank 8 is carried out to get the average density .sub.C greater than the density .sub., but less than 0.8 . In this procedure, the calibration of the bushing surfaces is provided.

(23) According to another embodiment of the production process, onto the metal rod 9 (FIG. 6), from both sides, additional annular shells 11 with a U-shaped meridian section and with perforated lateral surfaces are placed until contacting the bushing blank 8, and then the punches 10 are introduced until contacting the shells 11. After that, in the mold sleeve 6, the final axial pressing of the bushing blank 8 is carried out to get the average density value .sub.C greater than .sub., but less than 0.8 , providing for the calibration of the bushing surfaces, as well as for pressing the bushing blank ends into the annular shells 11.

(24) A representative structure of a thin-walled elastoporous part in the form of a bushing in the MR material, according to the first embodiment of the process, is illustrated in FIG. 7.

(25) A representative structure of a thin-walled elastoporous part in the form of a bushing in the MR material, provided with annular shells with a U-shaped meridian section and with perforated lateral walls, according to the production process of the present invention, is illustrated in FIG. 8. It is necessary to observe, that at the second pressing stage, the MR material of the bushing blank completely fills the internal space of the meridian section U-shaped annular shells 11, including the punched openings. This fact provides for a reliable fixation of the shells on the ends of the elastoporous part and for the increase of the active filtering surface, with simultaneous reduction of dead zones.

(26) Example. In laboratory conditions, thin-walled elastoporous parts in the form of bushings made in MR material were manufactured from stainless steel wire of diameter d=0.2 mm, steel grade X-12Cr18Ni10Ti, GOST 18143-72 (wire material density p=7.8 g/cm.sup.3). The dimensions of a finished bushing: outer diameter D.sub.O=95 mm, inner diameter D.sub.I=85 mm, height H.sub.C=70 mm. The weight of the part is 300 g, the average density of the MR material .sub.C=3.03 g/cm.sup.3.

(27) First, wire fragments in the form of extended spirals with the outer diameter d.sub.1=0.2 mm and the coil lead of 1.2 mm were obtained. The resulting fragments were used to mold a flat rectangular blank with the dimensions 2001000 mm. In this case, the average density of the flat blank was selected on the basis of a calculated range of values .sub.3=(2.02.8)B.sub.1=0.40.6 g/cm.sup.3, where

(28) $B_1={\left(\frac{d}{d_1}\right)}^2,$
and was adopted equal to 0.46 g/cm.sup.3.

(29) Then, the flat blank was submitted to pressing with rollers in the direction perpendicular to the blank plane until obtaining the average density .sub.=0.88 g/cm.sup.3, that was selected from a calculated range of values .sub.=(1.52.0)B.sub.2=0.81.1 g/cm.sup.3, where

(30) $B_2={\left(\frac{d}{d_1}\right)}^{1.5}.$

(31) A compressed flat blank was wounded in 4 layers onto a polyurethane cylinder with the diameter of 80 mm and the height of 210 mm. Maintaining the blank under tension, the outer diameter D.sub.O of the combination was obtained equal to 95 mm.

(32) At the next pass, the combination was placed into a mold sleeve between cylindrical punches with flat continuous ends, and the axial force of 16 t was applied to the same to carry out a radial-axial pressing. In this case, the average density of the bushing blank was 1.3 g/cm.sup.3, and its inner diameter D.sub.I=85 mm.

(33) Through the opening formed in the bushing blank, a metal rod with the outer diameter D.sub.O=85 mm was passed, and punches with annular working surfaces were mounted. In the case of manufacture of elastoporous parts with shells, the last were mounted onto said rod before mounting the punches. The final axial pressing of the bushing blank was carried out until getting the finished bushing height H.sub.C=70 mm, applying the pressing force of 25 t. In so doing, the average density of the MR material in the finished bushing .sub.C=3.03 g/cm.sup.3.

(34) As a result, a new process for the manufacture of thin-walled elastoporous parts in the form of bushings in the MR material is provided, said bushings showing high reliability with predetermined characteristics of elastoporosity. The last parameter is provided by the selection of the most efficient relationships for the geometrical parameters, as well as by the proportion of the pressing for a flat blank, of the radial-axial pressing for a bushing blank and of the axial pressing for the finished bushing. The above described relationship of the technological parameters for said passes enables to develop a rational technological procedure implementing the process of the present invention. Furthermore, the productivity is increased and the manufacture of a wide range of thin-walled bushing-type elastoporous parts in the MR material is simplified, said parts demonstrating a high reliability and being used for the purposes of the anti-vibration protection, of the filtering liquid and gaseous media, etc.