Method for Producing a Sintered Part

Abstract

A method for producing a sintered part, having at least the following steps: a) providing a sintered part, said sintered part having a first end face, a second end face arranged at a distance from the first end face in an axial direction, and a circumferential surface between the end faces; b) arranging the sintered part in a tool; c) applying a first pressure force, which acts on the end faces at least in the axial direction, to the sintered part by the tool; and d) applying a second pressure force, which acts on the circumferential surface at least in a radial direction, to the sintered part, wherein the sintered part is reshaped at least by the second pressure force, or mechanically processing the sintered part. Steps c) and d) are carried out at least partly simultaneously.

Claims

1. A method for producing a sintered part, wherein the method comprises at least the following steps: a) providing a sintered part, wherein the sintered part has a first end face, a second end face spaced apart in an axial direction, and a peripheral surface between the end faces; b) arranging the sintered part in a tool; c) using the tool to subject the sintered part to a first compressive force acting on the end faces at least in the axial direction; d) subjecting the sintered part to a second compressive force acting on the peripheral surface at least in a radial direction, wherein the sintered part is shaped at least by the second compressive force, or mechanically processing the sintered part, wherein steps c) and d) are carried out at least partially at the same time.

2. The method as claimed in claim 1, wherein the first compressive force is at least 200 megapascals.

3. The method as claimed in claim 1, wherein the first compressive force is applied to the sintered part over the entire first end face and the entire second end face.

4. The method as claimed in claim 1, wherein the second compressive force is applied to the sintered part via at least one rolling tool.

5. The method as claimed in claim 1, wherein a plurality of rolling tools are arranged in the tool in a peripheral direction, wherein the second compressive force is applied to the sintered part at least intermittently at the same time by multiple rolling tools.

6. The method as claimed in claim 1, wherein the sintered part is pressed quasi-isostatically by the first compressive force and the second compressive force.

7. The method as claimed in claim 1, wherein the sintered part is also at least partially shaped by the first compressive force.

8. A tool for producing a sintered part by a method as claimed in claim 1, wherein the sintered part has a first end face, a second end face spaced apart in an axial direction, and a peripheral surface between the end faces, wherein the tool at least comprises: a receptacle, in which the sintered part is arrangable for further processing, a punching unit for subjecting the sintered part arranged in the receptacle to the first compressive force, and at least one rolling tool for subjecting the sintered part arranged in the receptacle to the second compressive force, or at least one processing tool for the mechanical processing of the sintered part arranged in the receptacle.

9. The tool as claimed in claim 8, at least comprising a control unit suitably designed to control the tool for the purpose of carrying out the method, wherein the control unit is able to control the first compressive force and additionally the second compressive force or the processing tool at least intermittently at the same time.

10. A sintered part, at least comprising: a first end face, a second end face spaced apart in an axial direction, and a peripheral surface between the end faces, wherein the sintered part is produced at least by a method as claimed in claim 1.

Description

[0067] The invention and the technical field will be explained in more detail below on the basis of the appended figures. It is to be noted that the invention is not intended to be limited by the exemplary embodiments mentioned. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the explanatory substantive matter illustrated in the figures and to combine these with other constituent parts and findings from the present description. In particular, it is to be noted that the figures and in particular the size ratios illustrated are only schematic. In the figures:

[0068] FIG. 1: shows a side view in section of a tool;

[0069] FIG. 2: shows a side view in section of a detail of the tool according to FIG. 1;

[0070] FIG. 3: shows a perspective view of at least part of the tool according to FIG. 1;

[0071] FIG. 4: shows a side view in section (left-hand side) and a perspective view in section (right-hand side) of a first embodiment variant of rolling tools in the tool according to FIG. 1; and

[0072] FIG. 5: shows a side view in section (left-hand side) and a perspective view in section (right-hand side) of a second embodiment variant of rolling tools in the tool according to FIG. 1.

[0073] FIG. 1 shows a side view in section of a tool 6. FIG. 2 shows a side view in section of a detail of the tool 6 according to FIG. 1. FIG. 3 shows a perspective view of at least part of the tool 6 according to FIG. 1. FIGS. 1 to 3 will be described jointly below.

[0074] The tool 6 comprises a receptacle 12, in which the sintered part 1 is arranged for further processing. The tool 6 also comprises an upper punching unit 13 above the receptacle 12 and a lower punching unit 13 below the receptacle 12 for the purpose of subjecting the sintered part 1 arranged in the receptacle 12 to the first compressive force 7. The lower punching unit 13 has a first mandrel 19 and a second mandrel 20 (or punch). The receptacle 12 is formed in this instance by way of the punching units 13. Furthermore, four rolling tools 10 are provided for subjecting the sintered part 1 arranged in the receptacle 12 to the second compressive force 9.

[0075] The rolling tools 10 are arranged in a radial direction 8 next to the receptacle 12 for the sintered part 1. The rolling tools 10 are arranged such that they can rotate with respect to the sintered part 1 and the punching units 13 and are able to rotate together around the sintered part 1 in the peripheral direction 11. For this purpose, the rolling tools 10 are arranged in a rotatable first tool part 16 which is mounted rotatably with respect to a stationary second tool part 17 via bearings 18.

[0076] Each rolling tool 10 comprises a roller 21, which is guided at least or exclusively in a peripheral direction 11 along the peripheral surface 5 of the sintered part 1. The second compressive force 9 is applied to the sintered part 1 via the roller 21. The roller 21 rolls on the sintered part 1 in the process. The outer peripheral surface of the roller 21 of the rolling tool 10 has a specific shape, with the result that this specific shape is transferred to the sintered part 1 via the rolling tool 10 in the course of the rolling operation. It can be seen in FIG. 2 that the roller 21 has a shoulder 22, which also supports the sintered part 1 with respect to the axial direction 3.

[0077] The sintered part 1 has a first end face 2, a second end face 4 spaced apart in an axial direction 3, and a peripheral face 5 between the end faces 2, 4.

[0078] The tool 6 comprises a control unit 14 suitably designed (equipped, configured or programmed) to control the tool 6 for the purpose of carrying out the method, with the control unit 14 being able to control the punching units 13 with the mandrels 19, 20, and therefore the first compressive force 7, and additionally the rolling tools 10 and the first tool part 16, and therefore the second compressive force 8, at least intermittently at the same time.

[0079] It is pointed out that, instead of e.g. one or each rolling tool 10 (or in addition thereto), a processing tool 15 may be arranged in the tool 6 for the purpose e.g. of machining the peripheral surface 5 of the sintered part 1.

[0080] FIG. 4 shows a side view in section (left-hand side) and a perspective view in section (right-hand side) of a first embodiment variant of rolling tools 10 in the tool 6 according to FIG. 1. Reference is made to the embodiments relating to FIGS. 1 to 3.

[0081] The sintered part 1 has a first end face 2, a second end face 4 spaced apart in an axial direction 3, and a peripheral face 5 between the end fac-es 2, 4.

[0082] Each rolling tool 10 comprises a roller 21, which is guided at least in a peripheral direction 11 along the peripheral surface 5 of the sintered part 1. The second compressive force 9 is applied to the sintered part 1 via the roller 21. The roller 21 rolls on the sintered part 1 in the process. The outer peripheral surface of the roller 21 of the rolling tool 10 has a specific shape, with the result that this specific shape is transferred to the sintered part 1 via the rolling tool 10 in the course of the rolling operation. The roller 21 has a shoulder 22, which also supports the sintered part 1 with respect to the axial direction 3.

[0083] It can be seen here that grooves 23, that is to say undercuts, running around the periphery of the peripheral surface 5 of the sintered part 1 can be created via the roller 21. Furthermore, a homogeneous density can be achieved even in regions with a low wall thickness 24.

[0084] FIG. 5 shows a side view in section (left-hand side) and a perspective view in section (right-hand side) of a second embodiment variant of rolling tools 10 in the tool 6 according to FIG. 1. Reference is made to the statements relating to FIGS. 1 to 4.

[0085] By contrast to the first embodiment variant, the rollers 21 in this instance have a smooth outer peripheral surface. The roller also has a conical portion 25, the angle 26 with respect to the axial direction 3 being less than 60 angular degrees, in this instance approx. 20 angular degrees. It is possible to achieve a homogeneous density even in the conical portion 25 here, too.

LIST OF REFERENCE SIGNS

[0086] 1 Sintered part [0087] 2 First end face [0088] 3 Axial direction [0089] 4 Second end face [0090] 5 Peripheral surface [0091] 6 Tool [0092] 7 First compressive force [0093] 8 Radial direction [0094] 9 Second compressive force [0095] 10 Rolling tool [0096] 11 Peripheral direction [0097] 12 Receptacle [0098] 13 Punching unit [0099] 14 Control unit [0100] 15 Processing tool [0101] 16 First tool part [0102] 17 Second tool part [0103] 18 Bearing [0104] 19 First mandrel [0105] 20 Second mandrel [0106] 21 Roller [0107] 22 Shoulder [0108] 23 Groove [0109] 24 Wall thickness [0110] 25 Conical portion [0111] 26 Angle