METHOD FOR MANUFACTURING A ROTATIONALLY SYMMETRICAL SHAPED ARTICLE

Abstract

A method for manufacturing a rotationally symmetrical shaped article, which has a cylindrical, concentric hub axially closed on one side, in a shaping process is performed such that at least one pressure roll is in contact with a rotating, closed, planar circular blank sheet and presses the material of the blank radially from the outside inward against a projecting part that runs upright on the circular blank such that the thickness of the circular blank decreases and the hub including a blind hole is formed.

Claims

1-13. (canceled)

14. A method for manufacturing a rotationally symmetrical shaped article having a concentric hub, which is produced by a forming process, closed axially on one side and formed in a cylindrical manner, the method comprising: causing at least one spinning roller to act on a rotating, closed and planar circular blank made of sheet metal, with which material of the circular blank, by reducing the thickness of the circular blank, is pressed against a projecting part standing upright against the circular blank radially from an outside to an inside by forming the hub with a blind hole.

15. The method of claim 14, wherein, from a flange radially adjoining the hub, a blank in form of a bell-shaped bottom part is formed by spinning or pressing.

16. The method of claim 15, wherein the blind hole comprises a base lying between the hub and the bell-shaped part.

17. The method of claim 14, wherein the circular blank is heated before or during the forming of the hub to a temperature of approximately 400° C. to 1200° C.

18. The method of claim 15, wherein the bell-shaped bottom part is provided by a non-cutting forming process with an inner contour, consisting of ball tracks for accommodating rolling bodies and cage tracks adjacent to the ball tracks.

19. The method of claim 14, wherein the hub is provided with an inner and/or outer toothing, wherein the teeth respectively extend in an axial direction of the hub.

20. The method of claim 18, wherein the ball tracks and the cage tracks are formed by shaping strips, which are movable linearly in parallel and against each other, in correspondence with a mold core that holds the circular blank in a twist-proof manner, under formation of a pivot pin.

21. The method of claim 18, wherein an edge region of the flange adjoining the hub is heated before or during the forming of the bell-shaped bottom part under hardening temperature.

22. The method of claim 21, wherein the bell-shaped bottom part is heated to the hardening temperature before or during the forming of the cage track in its region to be formed.

23. The method of claim 20, wherein the shaping strips are pressed against the circular blank.

24. The method of claim 18, wherein the ball tracks are hardened after their formation.

25. The method of claim 19, wherein the inner and/or outer toothing is shaped during forming of the hub.

26. The method of claim 14, wherein the blind hole is formed axially within the hub.

Description

[0024] The method in accordance with the invention will be explained below in closer detail by reference to the enclosed drawings, wherein:

[0025] FIG. 1 shows a sectional schematic side view of an apparatus for carrying out the method;

[0026] FIG. 2 shows a perspective view of the shaped article which is formed into a blank in a further method step;

[0027] FIG. 3 shows a longitudinal sectional view of the shaped article according to FIG. 2;

[0028] FIGS. 4 and 5 show an apparatus for further machining the blank according to FIG. 2 in different views;

[0029] FIG. 6 shows a perspective view of a shaped article which is completed with respect to its shaping.

[0030] FIG. 1 illustrates the method in accordance with the invention, with which a rotationally symmetrical shaped article 1 is produced by a forming process, which article comprises a concentric hub 4, wherein the axially extending hub 4 is closed on one side.

[0031] For this purpose, a closed circular blank 2 is provided for this purpose, which is planar in this case in a preferred embodiment and is indicated in the drawing by the dot-dash line. Said blank is then inserted into a die 5, which circumferentially comprises an abutment chuck 9, on which the circular blank 2 can be supported at its outer edge during the subsequent process and then rests thereon.

[0032] On the side facing away from the die 5, a projecting part 6 runs upright on the circular blank 2, which comprises with distance a stop shoulder 7.

[0033] The circular blank 2 is then made to rotate. For the purpose of forming the hub, a rotatable spinning roller 8 acts in a method step on the rotating circular blank 2 from the outer edge under radial advancement, with which the material, by reducing the thickness of the circular blank 2 in the region preferably covered by the spinning roller 8, is preferably pressed under radial movement of the spinning roller 8 from the outside to the inside. The spinning roller 8 preferably axially enters the circular blank 2 at first close to the outer edge of the circular blank 2 and is moved radially to the inside at this time or during the process. During the first plunging, the circular blank 2 preferably slightly widens and moves against the abutment chuck 9.

[0034] The material is then pressed against the projecting part 6 by formation of the hub 4. In this process, the circular blank 2 is preferably reduced in some sections in its thickness, thus producing in this region a radially extending flange 3, which is illustrated with the solid line. The used material is a metal.

[0035] The material pressed against the projecting part 6 is guided up to the stop shoulder 7 or it flows up to this point, so that the stop shoulder 7 thus forms a length limitation for the hub 4.

[0036] A blind hole 12 with a closed base 13 (FIG. 3) is formed during the forming of the hub 4 by the continuously closed circular blank 2. The blind hole 12 is formed within the hub 4. The base 13, which seals the hub 4 axially on one side so that the blind hole 12 is formed, extends radially from the hub radially to the inside. The hub 4 is open at the end facing away from the flange 3 and the base 13 of the blind hole 12.

[0037] In a subsequent method step, a blank 10 with a bell-shaped bottom part 11 is formed from the flange 3. The blank 10 further comprises the hub 4. A contour mandrel (not shown), which is described in DE 10 2013 101 555 B3, can preferably be used for this purpose. The flange is integrally attached thereto or placed thereon, e.g. by means of one or several spinning rollers in a spin forming method by pressing or by means of a press in a pressing method.

[0038] The blank 10 formed in this manner is shown in FIGS. 2 and 3. FIG. 3 shows especially clearly that the base 13 seals the blind hole 12 towards the bell-shaped bottom part 11. This is especially advantageous. FIGS. 2 and 3 thus show an exemplary and preferred bell shape. The bell-shaped bottom part 11 extends on one side of the base 13. The hub 4 extends axially on the other side of the base 13. The hub 4 and the bell-shaped bottom part 11 are thus separated from each other by a base 13.

[0039] FIG. 6 shows a pivot pin as a finished end product, having an inner contouring, consisting of six ball tracks 15 in the example and adjoining cage tracks 16, wherein the ball tracks 15 are used for accommodating the rolling balls, whereas the cage tracks 16 form an interlocking retainer for the rolling balls.

[0040] For the purpose of forming the ball tracks 15 and the cage tracks 16 on the inside of the bell-shaped bottom part 11, stamping beams 17 are provided, which are linearly movable in parallel in opposite directions and comprise shaping strips 20 which are arranged on their mutually facing sides. The ball tracks 15 and the cage tracks 16 are integrally formed by means of said shaping strips 20 in a further method step on the blank 10 with the hub 4 and the bell-shaped bottom part 11, which blank is placed on a mould core 21. The shaping strips 20, with respect to the inner contouring of the bell-shaped bottom part 11, respectively form a female die and the mould core 21 a male die. The mould core 21 is rotated together with the blank 10. The shaping strips are moved tangentially on the blank 10, so that the ball tracks 15 and the cage tracks 16 are formed.

[0041] In this process, the blank 10 lies with its bell-shaped bottom part 11 between the shaping strips 20, which are pressed during the movement against the bell-shaped bottom part 11, so that the inner contour is formed with the ball and cage tracks 15, 16.

[0042] For the purpose of synchronous adjustment of the two stamping beams 17, they each comprise a toothed rack 18 on their mutually facing sides, which mesh with a gearwheel 19 of the mould core 21, wherein the blank 10 is retained in a rotationally fixed manner on the mould core 21.

[0043] An inner toothing can already be introduced into the hub 4 during the production of the shaped article 1, wherein the teeth extend in the axial direction of the hub 4. In this case, a respective shaping of the projecting part 6 is necessary, which apart from that rotates jointly with the circular blank 2.

[0044] A toothing can also be introduced into the outer jacket surface of the hub 4, wherein both the inner as well as the outer toothing, in the event of respective configuration of the stamping beams 17, can also be introduced during the forming of the inner contour of the bell-shaped bottom part 11.

[0045] Notice must be taken that the individual method steps can be carried out on an apparatus which comprises a single machine which is converted for the different following method steps or on an apparatus with several adjacently arranged machines on which the individual method steps are carried out.

LIST OF REFERENCE NUMERALS

[0046] 1 Shaped article [0047] 2 Circular blank [0048] 3 Flange [0049] 4 Hub [0050] 5 Die [0051] 6 Projecting part [0052] 7 Stop shoulder [0053] 8 Spinning roller [0054] 9 Abutment chuck [0055] 10 Blank [0056] 11 Bottom part [0057] 12 Blind hole [0058] 13 Base [0059] 14 Pivot pin [0060] 15 Ball track [0061] 16 Cage track [0062] 17 Stamping beam [0063] 18 Toothed rack [0064] 19 Gearwheel [0065] 20 Shaping strip [0066] 21 Mould core