METHOD FOR PRODUCING A SINTERED JOINT WITH HIGHLY RADIAL PRECISION

Description

[0001] The present invention relates to a method for producing a sintered part with high radial precision. Furthermore, the invention relates to the use of a set of sintered joining elements for joining the sintered joining elements to form a sintered part with high radial precision.

[0002] A common method for post-treating sintered parts is calibration. This process, known as repressing or calibration, ensures dimensional accuracy. For components intended for rotation, calibration often focuses on achieving dimensional accuracy on surfaces oriented parallel to the part's axis of rotation. Calibration is performed under high pressure in a calibration die. However, in cases where dimensional accuracy is particularly critical, additional machining operations, such as grinding, turning, milling, or drilling, are often necessary. These additional machining steps, however, come with the disadvantage of increased effort.JP H07 317512 A and JP 3 183469 B2 disclose a method for joining radially symmetrical sintered parts with an internal or external deformable element. US 6 101 713 A discloses a method in which radially symmetrical sintered parts are directly joined using a calibration press.

[0003] The invention is based on the objective of being able to produce and provide a sintered part with high radial precision, which is improved in its properties and manufacturing effort compared to previously known sintered parts.

[0004] The problem is solved by a method for producing a sintered part with high radial precision, comprising the features of claim 1. Further advantageous embodiments and developments are described below. One or more features from the claims, the description, and the figures can be combined with one or more features therein to form further embodiments of the invention. In particular, one or more features from the independent claims can also be replaced by one or more other features from the description and / or the figures. The proposed claims are to be understood only as a draft for formulating the subject matter, without limiting it.

[0005] A method for manufacturing a sintered part with high radial precision is provided. The sintered part is manufactured from at least a first sintered joining part and a second sintered joining part. The method comprises at least the following steps: Joining the first sintered component to the second sintered component; achieving high radial precision, comprising the deformation of at least one radial deformation element. The deformation of the radial deformation element is effected at least by means of a calibration tool. The deformation of the radial deformation element occurs at least substantially as plastic deformation of the radial deformation element.

[0006] The term "sintered part" refers specifically to a component that has already undergone a sintering process. Preferably, no further sintering of the sintered part is required; however, it is also possible that further sintering of the sintered part is planned and / or necessary.

[0007] The term sintered joining part also refers to a component that has already been sintered and is intended for joining to a sintered part by means of joining with at least one other sintered joining part.

[0008] The term high-precision radial accuracy refers in particular to the dimensional accuracy of a lateral surface of the sintered part, at least along a partial section of the axial extent of the sintered part, which is oriented parallel to a provided axis of rotation of the sintered part.

[0009] In a preferred embodiment, the high-precision radial accuracy is a radial precision at at least one axial position of the axial extent of the sintered part.

[0010] In a particularly preferred embodiment of the method, the high-precision radial precision is a radial precision along the entire axial extent of the sintered part, wherein the outer surface of the sintered part particularly preferably has the high-precision radial precision completely.

[0011] In a specific embodiment, the sintered part is essentially rotationally symmetrical and has a lateral surface corresponding to the lateral surface of a circular cylinder. In this particular design, the high radial precision refers to an outer diameter of the lateral surface, whereby for all outer diameters within accepted tolerances, the diameter achieves its required dimensional accuracy at every position along the axial extent of the sintered part.

[0012] The term high-precision radial accuracy refers to a precision in a radial direction of the sintered part with a tolerance of less than + / - 0.050 mm in the radial direction, so that no extent deviates more or less than 0.050 mm from its intended dimensional accuracy.

[0013] In a preferred embodiment of the invention, the high-precision radial accuracy has a tolerance of less than ±0.025 mm, meaning that no deviation in the radial dimension of more than 0.025 mm higher or lower than the intended dimensional accuracy occurs. In a particularly preferred embodiment of the invention, the radial precision has a tolerance of less than ±0.015 mm, meaning that no deviation in the radial dimension is more or less than 0.015 mm from its intended dimensional accuracy.

[0014] The term "calibration tool" can refer to a separate tool used to calibrate a sintered part that has already been joined, particularly in another tool. However, it can also refer to a section of a tool where, in addition to calibration, the sintered part has already been joined to at least the first and second sintered parts. For example, a subsequent tool might be used in which joining and calibration take place sequentially. Alternatively, joining and calibration might occur simultaneously, at least temporarily, with joining transitioning seamlessly into calibration.For example, it may be planned that at a time when calibration is already taking place, the step of achieving high radial precision in an area of ​​the calibration tool has already begun.

[0015] In a specific embodiment of the method, it is provided that the achievement of high radial precision is essentially achieved by deforming the radial deformation element or elements.

[0016] For example, it may be provided that achieving high radial precision essentially by deforming the radial deformation element or elements is understood to mean that at least 75% of the volume change required to achieve high radial precision is contributed by volume change of the radial deformation element or elements.

[0017] For example, it may be provided that achieving high radial precision essentially by deforming the radial deformation element or elements is understood to mean that at least 85% of the volume change required to achieve high radial precision is contributed by volume change of the radial deformation element or elements.

[0018] For example, it may be provided that achieving high radial precision essentially by deforming the radial deformation element or elements is understood to mean that at least 95% of the volume change required to achieve high radial precision is contributed by volume change of the radial deformation element or elements.

[0019] For example, it may be provided that achieving high radial precision essentially by deforming the radial deformation element or elements is understood to mean that at least 99% of the volume change required to achieve high radial precision is contributed by volume change of the radial deformation element or elements.

[0020] The volume change refers to the volume change of the total volume of the sintered joining parts and the radial deformation elements.

[0021] In a further embodiment of the process, it is provided that an outer deformation element is positioned during the joining process step, such that at least the first sintered joining element and / or at least the second sintered joining element are at least partially surrounded by the outer deformation element. The outer deformation element then forms a radial deformation element, which is designed as an outer radial deformation element.

[0022] The term "outer deformation element" refers to an independent component that, in addition to the first and second sintered joining elements, is positioned, for example, before or during the joining of the first and second sintered joining elements, such that the outer deformation element at least partially surrounds the first and / or second sintered joining elements. The term "surrounding the first and / or second sintered joining element" refers to an arrangement in which the outer deformation element at least partially encloses, encompasses, and / or preferably rests on a lateral surface of the first and / or second sintered joining element.

[0023] It is particularly preferred that the outer deformation part rests on an edge, at least partially, on which the first sintered joining part and / or the second sintered joining part are joined.

[0024] The advantage of arranging an external deformation element is that, in the course of achieving high radial precision, the degrees of freedom of the external deformation element allow it to adapt very well to the calibration tool and to assume its reference quality with regard to positional and / or location tolerances and / or form quality, i.e., radial precision.

[0025] In particular, it may be provided that the outer deformation part consists of a material that is comparatively easy to deform compared to the first sintered joining part and / or the second sintered joining part, in particular a plastically deformable material, so that deformability of the outer deformation part is preferably achieved.

[0026] For positioning the outer deformation element, it can be provided, for example, that the outer deformation element is retained axially by a region of the first sintered joining element which has a radial extent greater than the extent of the outer deformation element, and / or that the outer deformation element is retained axially by a region of the second sintered joining element which has a radial extent greater than the radial extent of the outer deformation element. In particular, axial positioning of the outer deformation element can be achieved by providing at least one retaining projection on the first sintered joining element and / or at least one retaining projection on the second sintered joining element.

[0027] In one embodiment of the process, in which both the first sintered joining part and the second sintered joining part each have a corresponding retaining projection with a distance between the projections in the joined state of the sintered part that corresponds to an axial extent of the deformation part, an exact positioning of the deformation part is achieved during the joining process.

[0028] In another embodiment of the process, it is provided that an inner deformation part is positioned during the joining process, and the inner deformation part: at least one first internal joining surface of the first sintered joining part, and / or at least one second internal joining surface of the second sintered joining part. at least partially covers it.

[0029] In a preferred embodiment, the inner deformation part, which is positioned during the joining process, covers the area after positioning. the first inner joining surface of the first sintered joining part and / or the second inner joining surface of the second sintered joining part completely.

[0030] The inner deformation part then functions as a radial deformation element, which is designed as an inner radial deformation element.

[0031] An internal radial deformation element arranged on at least one internal joining surface has the advantage, among others, of facilitating the exact positioning of the first sintered joining part relative to the second sintered joining part.

[0032] The term "internal joining surface" refers to an inner surface of a recess, i.e., located within the interior of the joined sintered part. An interior is characterized by being at least partially enclosed by the outer surface. The term "external joining surface" refers to a surface of the raised area. The internal deformation element is located at least partially between an internal joining surface and an external joining surface. However, it is also possible for the internal deformation element to extend over the entire axial extent of an internal joining surface and / or an entire axial extent of an external joining surface.

[0033] The positioning of the outer and / or inner deformation element during the joining process is understood to mean that, from the presence of the first sintered joining element, the second sintered joining element, and the outer and / or inner deformation element, the positioning of the inner and / or outer deformation element takes place to produce a sintered part with high radial precision. This positioning can, for example, be performed as a first step independent of the joining of the first sintered joining element with the second sintered joining element, for instance, by placing the deformation element over the sintered joining element(s) or by inserting the deformation element into the sintered joining element(s). It can also be provided, for example, that the outer and / or inner deformation element is positioned in a loose fit, with frictional and / or force-fit.It may also be provided that at least in part of the joining step the joining of the outer and / or the inner deformation part also takes place, that these process steps therefore overlap at least partially.

[0034] It includes the positioning of more than one internal deformation part and / or more than one external deformation part during the joining process.

[0035] In a further embodiment of the process, it can be provided, for example, that one, several or preferably all deformed parts are joined to one or more sintered joining parts during the joining process in a frictional, formative, force- and / or material-liquid manner.

[0036] In another embodiment, it may be provided, for example, that during the achievement of high radial precision, one, several, preferably all, deformation parts are connected to one or more sintered joining parts by friction, form, force and / or material bonding.

[0037] In intermediate stages, it is also provided that, at least temporarily during the process, the joining and the achievement of high radial precision take place at least partially simultaneously. It can also be provided, for example, that the at least one deformed part is joined with one or more sintered joining elements, while the joining and the achievement of high radial precision are each carried out at least partially simultaneously.

[0038] Performing the joining process and achieving high-precision radial alignment at least partially simultaneously has the advantage of reducing the process time and achieving higher accuracy in radial precision, particularly in the radial positioning of the sintered components relative to each other.

[0039] In a further development of the procedure, it is provided that at least one area of ​​at least one internal joining surface of the first sintered joining part, and / or at least one area of ​​at least one internal joining surface of the second sintered joining part, and / or at least one area of ​​at least one external joining surface of the first sintered joining part, and / or at least one area of ​​at least one external joining surface of the second sintered joining part at least one radial protrusion that forms a radial deformation element, designed as an internal radial deformation element.

[0040] The term "radial elevation" refers to a raised area originating from the first and / or second sintered component, which is an integral part of the sintered component and is at least partially raised in a radial direction. An advantage of this type of raised area is that it can be incorporated into the green compact during the powder pressing process, which is used to produce the green compact that will later be sintered into the sintered component. For example, the radial elevation can be formed into the future sintered component by negatively molding it in a press die.

[0041] A radial elevation is a raised feature that has at least one component extending in a radial direction. For example, the radial elevation can be a linear feature, which has the advantage that such a linear feature can be easily created during the pressing of powder to produce a green compact, which later becomes the sintered joining part. It is also possible for the elevation to be a knob or another geometric shape.

[0042] The presence of a radial protrusion offers the advantage that, when joining the individual parts—the first sintered joining part and the second—the parts align themselves at the contact surfaces with the tool elements of the joining tool and / or the calibration tool. Precise manufacturing and positional tolerances of the tool components, combined with a stable tool design, mean that, with more than one protrusion, shape deviations of the sintered joining parts are compensated for by locally varying degrees of deformation within the protrusions. Due to the presence of the protrusions, even a slight radial deviation from the optimal position is sufficient to exceed the yield stress in the contact zone. Consequently, even small deviations and the resulting low pressures cause plastic deformation, particularly of the protrusions.Simultaneously, the material of the sintered joining element, which has raised sections, can flow into a space located between at least one first and a second raised section. The presence of at least one raised section therefore leads to a very precise alignment of at least the first and second sintered joining elements relative to each other.

[0043] A particularly preferred embodiment of the method is provided in which at least two protrusions are present. A particularly preferred embodiment is the arrangement of an even greater number than two protrusions over the entire circumference, preferably uniformly. It is also possible, for example, that protrusions are present on both the first sintered joining part and the second sintered joining part.

[0044] A further embodiment of the process provides that the achievement of high radial precision occurs at least partially simultaneously with the joining of the first and second sintered components. For example, it can be provided that the joining of the first and second sintered components and the achievement of high radial precision are carried out sequentially using a progressive die, so that the transition from joining the first and second sintered components to achieving high radial precision is solely based on their positions, whereby a continuous or a discontinuous transition is possible.

[0045] Another way the procedure can be designed is, for example, to provide that for joining at least a first process step is carried out using at least one joining tool and / or for achieving high radial precision at least a second process step is carried out using a calibration tool designed as a separate calibration tool and / or using a calibration tool designed as a calibration area of ​​a combined follower tool.

[0046] Such a design of the process for manufacturing a sintered part with high radial precision has the advantage that the calibration tool can be set and / or replaced independently of the tool used for joining, thereby achieving greater flexibility.

[0047] A further development of the process for manufacturing a sintered part with high radial precision involves removing the sintered part with high radial precision from the calibration tool after achieving this high radial precision. In other words, the sintered part is removed with high radial precision.

[0048] One of the advantages of removing the sintered part from the calibration tool with high radial precision is that the desired high radial accuracy is already present immediately after calibration. This means that the reproducibility of the diameter dimension and the quality of the reference and form properties no longer require post-processing after plastic deformation or calibration. In particular, no machining, such as of the diameter, the cylindrical surfaces, and / or the reference and functional surfaces, is necessary; grinding, turning, milling, and / or drilling are no longer required. This results in the considerable advantage of a less time-consuming, material-intensive, and labor-intensive production of the sintered parts.

[0049] In one embodiment of the process, the first sintered joining part and the second sintered joining part are pressed against each other under axial pressure exerted by a pressing tool. This pressing action ensures the precise height of the molded part.

[0050] The term "joining surface" refers to a side on which, in a sintered part intended for rotational movement, the axis of rotation is oriented perpendicularly or at least substantially perpendicularly. The term "joining surface" includes raised or recessed areas. Therefore, it is not necessary for a joining surface to be perfectly flat.

[0051] The term "precise part height" means that the sintered part has a height that allows for its immediate use for its intended purpose. Specifically, it means that no further mechanical processing, such as machining (e.g., grinding or turning), is required.

[0052] Pressing the first and second sintered components together using a press tool means that axial pressure is applied to at least one of the components. The press tool does not necessarily have to be the same tool used for the joining process. Applying axial pressure does not mean that pressure is exerted directly on one or more of the first and second components. It is also possible, for example, to join more than two components, with only one or both components, or even neither, coming into direct contact with the press tool.The term "pressing against each other" in a joined state of the sintered part includes in particular an embossing of the sintered part, i.e. an application of pressure in an axial direction to achieve the intended height dimension.

[0053] In one embodiment, it may be provided in particular that the molded part height has a tolerance of less than + / - 0.05 mm, i.e., that the distance between the end faces of the sintered part is less than 0.05 mm greater or less than the intended value.

[0054] In a preferred embodiment of the invention, it is provided that the molded part height has a tolerance of less than + / - 0.025 mm, i.e., that the distance between the end faces of the sintered part is less than 0.025 mm greater or less than the intended value.

[0055] In a particularly preferred embodiment, it is provided that the molded part height has a tolerance of less than + / - 0.15 mm, i.e., that the distance between the end faces of the sintered part is less than 0.015 mm greater or less than the intended value.

[0056] In one embodiment of the method, it may be provided that the first sintered joining part has at least one first deformation element arranged on the first joining surface and / or the second sintered joining part has at least one second deformation element arranged on the second joining surface. For example, it is provided that deformation of at least one of the deformation elements is brought about by pressing the parts together.

[0057] The term deformation element can, for example, refer to a protrusion which is integrally present in the first sintered joining part as the first deformation element and / or in the second sintered joining part as the second deformation element.

[0058] In a further embodiment of the method, the first deformation element, arranged on the first joining surface, is inserted into a first receiving recess arranged on the second joining surface. It can also be provided that at least the second deformation element, arranged on the second joining surface, is inserted into a second receiving recess arranged on the first joining surface. This ensures that the deformation elements are positioned in a direction perpendicular to the axial direction.

[0059] For example, it may be planned that joining, achieving high radial precision and embossing take place in the same process step.

[0060] It may also be provided, for example, that a joining process takes place as a first step and then, as a further step, embossing and / or achieving high-precision radial accuracy takes place, so that the joining and embossing are carried out as sequential process steps.

[0061] Similarly, it may be provided, for example, that the joining process transitions continuously into the embossing and / or the achievement of high radial precision by carrying out both process steps in the same tool.

[0062] The sequence and design of the transition and / or overlap of the process steps joining, embossing and / or achieving high radial precision can be carried out in any order.

[0063] Furthermore, the use of a component set is provided to achieve assembly into a sintered part with high radial precision, wherein the sintered part can be removed from a calibration tool with high radial precision. Preferably, one of the described methods is used for assembly into the sintered part.

[0064] The parts kit includes at least: A first sintered joining part, a second sintered joining part, and a radial deformation element.

[0065] The first and second sintered joining elements are each sintered parts, comprising, for example, sintered steel, sintered metal, or sintered ceramic. Preferably, the first and / or the second sintered joining element are also components consisting entirely of sintered metal, sintered steel, or sintered ceramic. The term "sintered joining element" is to be understood as meaning that the first sintered joining element is suitable and intended to be joined with the second sintered joining element to form a sintered part or a part thereof.

[0066] It may therefore be intended, for example, that one or more additional components are provided for joining the sintered part, or that their use is possible or even necessary. Such additional components could be, for example, further sintered joining elements; however, they could also be, for example, deformation elements provided in addition to the sintered joining elements, which form one or more radial deformation elements.

[0067] It may therefore be provided that, in addition to the first sintered joining part and the second sintered joining part, the set of parts includes any number of further sintered joining parts or other components.

[0068] The term "radial deformation element" refers to an element designed for deformation in a radial direction. A radial direction is defined as a direction perpendicular, or at least substantially perpendicular, to an axial direction of the sintered part. However, this does not necessarily imply that the sintered part must be rotationally symmetric. Rather, in sintered parts designed for rotation or partial rotation, an axial direction lies on the axis of rotation. In the special case of a rotationally symmetric component or a substantially rotationally symmetric component, an axial direction lies on the axis of symmetry.

[0069] The radial deformation element may be a separate element, applied before or during the joining of the sintered part to the first and / or the second sintered joining part.

[0070] In one embodiment of the component set, it may be provided, for example, that the component set has an internal deformation element which is used during the joining process. at least partially covering a first internal joining surface of the first sintered joining part and / or at least partially covering a second internal joining surface of the second sintered part. is positionable and forms a radial deformation element, which is designed as an internal radial deformation element.

[0071] For example, it may be provided that in addition to covering, there is at least partial or complete covering, which denotes contact of the inner deformation part with the first inner joining surface and / or the second inner joining surface.

[0072] The term "inner radial deformation element" refers to a radial deformation element which, during joining, is surrounded at least over part of its axial extent by at least part of the first sintered joining part and / or at least part of the second sintered joining part, so that in the finished joined sintered part the inner radial deformation element is located at least partially inside the sintered part.

[0073] In another embodiment of the component set, it may be provided, for example, that the component set has an outer deformation part which is used during the joining process. at least the first sintered joining part at least partially circumferentially and / or at least the second sintered joining part at least partially circumferentially. is positionable and forms a radial deformation element, which is designed as an outer radial deformation element.

[0074] The term "external radial deformation element" refers to such a radial deformation element which, during and after joining, i.e., in the joined sintered part, forms at least a part of the lateral surface of the sintered part with a part of its surface.

[0075] It is provided that the first sintered joining element and / or the second sintered joining element are sintered joining elements which have at least a section of an approximately ring-shaped or annular cross-section, and that the outer radial deformation element is furthermore designed as a ring. It is provided that the radial deformation element designed as a ring has an inner diameter which corresponds substantially to the outer diameter of the first sintered joining element and / or the second sintered joining element, so that the outer deformation element in the form of a ring can be arranged at least partially circumferentially around the sintered joining elements and thereby forms a radial deformation element that is designed as an outer radial deformation element.

[0076] In a further embodiment of the component set, it is provided that the first sintered joining part has a first radial retention projection and / or the second sintered joining part has a second radial retention projection for the axial positioning of the outer deformation part in the joined state of the sintered part.

[0077] The radial retention projection is a radial extension extending at least over an angular range of the sintered joining part in a radial direction beyond radial extensions present at other axial positions of the sintered joining part, which causes an outer deformation part positioned in an at least partially circumferential arrangement around the first sintered joining part and / or the second sintered joining part to be positioned axially by the projections.

[0078] In a further embodiment of the component set, it is provided that at least one area of ​​at least one internal joining surface of the first sintered joining part, at least one area of ​​at least one internal joining surface of the second sintered joining part, at least one area with at least one external joining surface of the first sintered joining part and / or at least one area of ​​at least one external joining surface of the second sintered joining part has at least one radial elevation designed as an internal radial deformation element.

[0079] For example, it may be intended that the radial protrusion creates an interference fit during joining.

[0080] The term "internal radial deformation element" encompasses the fact that, in the joined state of the sintered part, the internal radial deformation element is located within the sintered part. A radial protrusion is characterized, in particular, by being formed from the material of one or more of the sintered joining parts and being integrally formed with the sintered joining part(s). The presence of a radial protrusion offers the advantage that, due to the reduction of the contact area between the first and second sintered parts during joining, the plastic deformation of the radial protrusion, which is more easily induced during joining, significantly improves the positioning of the first sintered part relative to the second sintered part.

[0081] Another embodiment of the set of parts can, for example, have one or more radial elevations, which are formed in one of the geometric shapes of spherical segment, truncated spherical segment, truncated cone, cuboid, truncated trapezoid, truncated pyramid or line elevation.

[0082] In the case where a radial elevation is designed as a linear elevation, it is preferably provided that the radial elevation is oriented in a direction parallel to an axial direction of the first sintered joining part and / or to an axial direction of the second sintered joining part. Designing the radial elevation as a linear elevation oriented in a direction parallel to an axial direction of the first sintered joining part and / or in a direction parallel to an axial direction of the second sintered joining part has the advantage that, during the production of the first sintered joining part and / or the second sintered joining part by axially pressing the pressed part and / or the green compact into a correspondingly shaped die, a particularly advantageous production of the sintered joining part is possible.

[0083] In a further embodiment of the component set, it may be provided, for example, that has a minimum extent of an upper contact surface of 0.2 mm in at least one dimension of the contact surface, has an extent of a base surface of 0.4 mm to 2.0 mm in at least one dimension and / or has a height of 0.1 mm to 2.0 mm between the base surface and the contact surface.

[0084] Designing the raised section according to the aforementioned values ​​has proven particularly advantageous in that it provides a sufficient volume of material to allow for adequate positioning of the first and second sintered components relative to each other through plastic flow. Furthermore, the resulting cavity between the first and second sintered components is small enough to be closed, for example, by plastic deformation and / or not to impede the proper functioning of the sintered component.

[0085] In a further embodiment of the parts set, the sintered part is designed to be a rotor for a camshaft adjuster, a pump ring, an oil pump housing, a stator or a shock absorber piston with high radial precision.

[0086] Further advantageous designs and developments are shown in the following figures. However, the details and features shown in the figures are not limited to them. Rather, one or more features can be combined with one or more features from the description above to create new designs. In particular, the following explanations do not serve to limit the respective scope of protection, but rather to illustrate individual features and their possible interactions with one another.

[0087] They show: Fig. 1: Exemplary embodiment of a sintered part as a stator, comprising a sintered joining part and a second sintered joining part, as well as a radial deformation element designed as an outer deformation element; Fig. 2: Exemplary embodiment of a sintered part as a stator, comprising a sintered joining part and a second sintered joining part, as well as a radial deformation element designed as an outer deformation element, in cross-section; Fig. 3: Exemplary embodiment of a sintered part as an oil pump housing, comprising a first sintered joining part, a second sintered joining part, and a visible radial deformation element designed as an outer radial deformation element; and Fig. 4: Exemplary embodiment of a sintered part as an oil pump housing, comprising a first sintered joining part, a second sintered joining part, and a visible radial deformation element designed as an outer deformation element, in cross-section, further showing a radial deformation element designed as an inner deformation element.

[0088] Fig. 1 An exemplary embodiment of a sintered part 1 is shown in an oblique view. The sintered part 1 is a stator of a camshaft adjuster. The sintered part 1 has a first sintered joining part 2 and a second sintered joining part 3, which are joined together. Furthermore, the sintered part 1 has an outer deformation part 5, which forms a radial deformation element. In the embodiment shown, the outer deformation part 5 is designed as a ring. The axial extent 12 of the outer deformation part 5 corresponds to the distance between a first radial retaining projection 13 of the first sintered part and a second radial retaining projection 14, wherein, in the embodiment shown, the first radial retaining projection 13 and the second radial retaining projection 14 are also rotationally symmetrical with respect to the axis of rotation 15 of the sintered part 1.The first radial retaining projection 13 and the second radial retaining projection 14 cause the outer deformation part 5 to be axially positioned. The radial extent of the outer deformation part 5 is greater at every point than the radial extent of both the first sintered joining part 2 and the second sintered joining part 3. This ensures that during calibration, plastic flow of the outer deformation part significantly contributes to achieving the high radial precision.

[0089] Fig. 2 is a cross-sectional representation containing the axis of rotation 15 of the in Fig. 1 to remove the design of a sintered part 1 with high radial precision.

[0090] Fig. 3 A further exemplary embodiment of a sintered part 1 can be seen in oblique view. In the Fig. 3 In this exemplary embodiment, the housing is an oil pump which has a first sintered joining part 2 and a second sintered joining part 3. Furthermore, the sintered part 1 of the Fig. 3 An outer deformation element 5, which is designed as a ring, is formed. The outer deformation element 5, designed as a ring, completely surrounds the first sintered joining element 2 and is formed in contact with a portion of the outer surface of the first sintered joining element 2. The Fig. 3 to remove an inner deformation part 4, which is also designed as a ring.

[0091] Fig. 4 is a cross-sectional representation of the in Fig. 3 to be seen from the sintered part shown. In addition to the already shown illustration of the Fig. 3 The characteristics to be extracted from the sintered part 1 are those in Fig. 4 The illustration also shows a first retaining projection 13, which, together with the second sintered joining element 3, achieves axial positioning of the outer deformation element 5. Furthermore, the cross-sectional representation of the Fig. 4 An inner deformation element 4, located inside the sintered part 1, is to be removed. In the illustration shown, the inner deformation element 4 is also designed as a ring and is inserted into a recess of the second sintered part 3. The dimensions and geometric design of the ring are such that the inner deformation element 4 completely covers a second inner mating surface 9 of the second sintered part 3 over the entire axial extent. The inner deformation element 4 completely covers a first outer mating surface 10 of the first sintered part 2 over the entire axial extent. Between the first outer mating surface 10 and the second inner mating surface 9, the inner deformation element 4 is arranged in an interference fit in the illustrated configuration.The arrangement of the inner deformation element shown ensures that the first sintered joining element 2 is axially positioned with high accuracy relative to the second sintered joining element 3 as a result of the plastic deformation of the inner deformation element 4, which acts as an inner radial deformation element. The axial positioning of the inner deformation element is achieved by the second retaining projection 14, which is formed in the recess of the second sintered joining element.

[0092] Part 2 completely detaches over the entire portion of its axial extent. Between the first outer joining surface 10 and the second inner joining surface 9, the inner deformation element 4 is arranged in an interference fit in the illustrated configuration. The illustrated arrangement of the inner deformation element ensures that the first sintered joining element 2 is axially positioned relative to the second sintered joining element 3 with high accuracy as a result of the plastic deformation of the inner deformation element 4, which acts as an internal radial deformation element. The axial positioning of the inner deformation element is achieved by the second retaining projection 14, which is formed in the recess of the second sintered joining element.

[0093] Fig. 5 A further exemplary embodiment of a sintered part 1 can be seen. In the case of the Fig. 5 The sintered part 1 shown is a sintered part 1 which is joined from a first sintered joining part 2 and a second sintered joining part 3. The first sintered joining part 2 has a recess, the inner surface of which forms a first internal joining surface 8. The second sintered joining part 3 is inserted into the recess. A friction-fit connection between the two sintered joining parts is achieved by means of internal radial deformation elements formed as radial protrusions 6, which are arranged on a second external joining surface 9 of the second sintered joining part 3 and which are plastically deformed when the second sintered joining part 3 is inserted into the recess of the first sintered joining part.

[0094] While the aforementioned radial elevations of the representation of the Fig. 5 which cannot be determined from the supervisory presentation Fig. 6 to be taken.

Claims

1. Method for producing a sintered part (1) with highly accurate radial precision, wherein the term highly accurate radial precision exhibits a tolerance in a radial direction of the sintered part (1) of less than + / - 0.050 mm in the radial direction, that is to say no deviation of an extent in the radial direction of more than 0.050 mm greater than or less than the intended, dimensionally accurate value arises. wherein the sintered part (1) is produced from at least - a first sintered joining part (2) and - a second sintered joining part (3), and wherein the method comprises at least the following steps: - joining the first sintered joining part (2) with the second sintered joining part (3), - deforming at least one radial deformation element, wherein the deformation of the radial deformation element is effected at least by way of a calibration tool and takes place at least as a plastic deformation of the radial deformation element; wherein an outer deformation part (5) and / or an inner deformation part (4), during the course of the joining process, is positioned so that at least the first sintered joining part (2) and / or at least the second sintered joining part (3) is at least partially encircled by the outer deformation part (5) or so that at least a first inner joining surface (8) of the first sintered joining part (2) and / or at least a second inner joining surface (9) of the second sintered joining part (3) is at least partially covered by the inner deformation part (4); wherein the outer and / or inner deformation part (4, 5) is a separate element that forms a radial deformation element; wherein imparting the highly accurate radial precision is effected by the deformation of the radial deformation element or of the deformation elements; wherein the sintered part (1) with highly accurate radial precision is a rotor for a camshaft adjuster, a pump ring, an oil pump housing, a stator or a shock-absorbing damper piston, or wherein the first sintered joining part (2) and / or the second sintered joining part (3) have a ring-shaped cross-section, wherein the radial deformation element is in the form of a ring.

2. Method as claimed in claim 1, characterized in that one, more, all, of the deformation parts are, during the joining process, connected in frictionally engaging, positively locking, non-positively locking and / or cohesive fashion to one or more sintered joining parts, and / or in that one, more, all, of the deformation parts are, during the imparting of the highly accurate radial precision, connected in frictionally engaging, positively locking, non-positively locking and / or cohesive fashion to one or more sintered joining parts.

3. Method as claimed in one of the preceding claims, characterized in that the imparting of the highly accurate radial precision is performed at least partially at the same time as the joining of the first sintered joining part (2) and of the second sintered joining part (3).

4. Method as claimed in one of the preceding claims, characterized in that - for the joining, at least one first process step is performed by way of at least one joining tool, and / or, - for the imparting of the highly accurate radial precision, at least one second process step is performed by way of a calibration tool in the form of a separate calibration tool and / or by way of a calibration tool in the form of a calibration region of a progressive tool.

5. Method as claimed in one of the preceding claims, characterized in that, after the imparting of the highly accurate radial precision, the sintered part (1) is removed from the calibration tool as a sintered part with highly accurate radial precision.

6. Method as claimed in one of claims 1 to 5, characterized in that, for the production of the sintered part (1), a first joining surface of the first sintered joining part (2) and a second joining surface of the second sintered joining part (3) are pressed against one another under the action of an axial pressing force exerted by way of a pressing tool, wherein at least one radial deformation element is positioned adjacent to a joining contact zone (7), wherein the first sintered joining part (2) has at least one first deformation element arranged on the first joining surface and / or the second sintered joining part has at least one second deformation element arranged on the second joining surface, and a deformation of at least one of the deformation elements is effected by way of the pressing against one another.

7. Use of a set of parts having sintered joining parts for joining of the sintered joining parts to form a sintered part (1) with highly accurate radial precision by utilizing a method as claimed in one claims 1 to 6, wherein the set of parts has: - at least one first sintered joining part (2), - at least one second sintered joining part (3), - at least one radial deformation element, wherein the set of parts has an outer deformation part (5) which is, during the course of the joining process, positionable so as to at least partially encircle at least the first sintered joining part (2) and / or at least the second sintered joining part (3); and / or wherein the set of parts has an inner deformation part (4) which is, during the course of the joining process, positionable so as to at least partially cover at least a first inner joining surface (8) of the first sintered joining part (2) and / or at least a second inner joining surface (9) of the second sintered joining part (3), wherein the outer and / or the inner deformation part (4, 5) is a separate element that forms a radial deformation element; wherein the radial deformation part is positioned so that the imparting the highly accurate radial precision is effected by the deformation of the radial deformation element or of the deformation elements.

8. Use as claimed in claim 7, characterized in that - the first sintered joining part (2) has a first radial retention projection (13) and / or - the second sintered joining part (3) has a second radial retention projection (14) for the axial positioning of the outer deformation part (5) in the joined state of the sintered part (1).