DE102022128906A1 - Tool for compacting a rolling element ramp - Google Patents

Abstract

The invention relates to a tool (10) for compacting a rolling element ramp (6) of a rolling element ramp element (1), which has been produced from a powder and has a first end face (3) and a second end face (5), and wherein in the first end face (3), the rolling element ramp (6) is designed as a recess, the tool (10) having a tool head (11) which has a rolling element (15), the rolling element (15) protruding over a tool head surface (16) and is held in the tool head (11) so that it can be rolled off.

Description

The invention relates to a tool for compacting a rolling element ramp of a rolling element ramp element, which has been produced from a powder, in particular a metallic one, and which has a first end face and a second end face, the rolling element ramp being designed as a depression in the first end face, and the Tool has a tool head.

The invention further relates to a method for compacting the rolling element ramps of a rolling element ramp element which has been produced from a powder, in particular a metallic one, and which has a first end face and a second end face, a rolling element ramp being formed as a depression in the first end face, and wherein a tool with a tool head is used to compact the rolling element ramp.

The invention also relates to a rolling element ramp element which has been produced from a powder, in particular a metallic one, with a first end face and a second end face, with a recessed rolling element ramp or a plurality of recessed rolling element ramps being formed in the first end face.

Ball ramp discs are used in drive technology in various structural units, for example as actuators with a variable axial distance. Such actuators can be used in clutches, brakes, etc., for example. However, it should be noted that this list is not exhaustive.

Due to the geometry of the ball ramps, ball ramp discs are correspondingly complex to produce, since the ball ramps require the highest level of accuracy in order to obtain high precision in the adjustment paths of the actuator equipped with them. For this reason, powder-metallurgical production is a good idea, as it is well known that complex component geometries can be produced relatively easily here (compared to other production processes). Methods of this type and the ball ramp discs produced therewith are already known from the prior art.

For example, describes the AT 521 299 A1 a method for the powder metallurgical production of a ball ramp element, comprising the steps of: producing a green body of the ball ramp element by pressing a metallic powder, wherein a plurality of recessed ball ramps are formed in the green body in a first end face; sintering the green compact; Machining of the sintered green compact on a second face.

From the AT 522 548 A1 a ball ramp actuator is known, comprising a first ball ramp disk, a second disk, which is preferably also designed as a ball ramp disk, and a plurality of balls, the second disk being arranged to be adjustable in the axial direction relative to the first ball ramp disk by means of the balls, the first ball ramp disk also having a the first face and the second washer have a second face, and the first face is disposed opposite to the second face in the axial direction, a first plurality of recessed ball ramps for receiving the balls being disposed in the first face, and preferably also a second plurality of recessed ball ramps being disposed in the second face recessed ball ramps are arranged for receiving the balls, with a plurality of balls being arranged per first recessed ball ramp and optionally per second recessed ball ramp. The first and/or the second ball ramp disc is/are preferably produced using a powder metallurgy process.

The problem with such ball ramp disks, however, is that high Hertzian pressures occur in the contact area of the balls as a function of the axial forces.

The present invention is based on the object of being able to subject a rolling body ramp element of the type mentioned at the outset to higher loads.

The object of the invention is achieved with the tool for compacting a rolling body ramp of a rolling body ramp element, in which it is provided that the tool head has a rolling body, the rolling body protruding over a tool head surface and being held in the tool head such that it can roll.

Furthermore, the object of the invention is achieved with the method mentioned at the outset for compacting a rolling element ramp of a rolling element ramp element, according to which a tool is used in which the tool head has a rolling element, the rolling element protruding over a tool head surface and being held in the tool head so that it can roll, and this tool is brought into contact with the rolling element on the surface of the rolling element ramp, after which the tool and/or the rolling element ramp element is caused to pivot, so that the rolling element rolls under pressure on the surface of the rolling element ramp and thereby compresses the rolling element ramp.

In addition, the object of the invention is achieved with the rolling element ramp element mentioned at the outset, in which the rolling element ramp has a ver has a sealed edge zone or the rolling element ramps have a compacted edge zone, with an edge zone density being at least 93% of the full density of the material of the rolling element ramp element.

The advantage here is that with the (local) compaction of the rolling element ramp, a rolling element ramp can be made available which, on the one hand, can still be produced from a powder and thus uses the advantages of this method, but which, on the other hand, has a rolling strength in the range of Wälzkörperrampe has that can not be achieved with known calibration methods. The improved rolling strength of the rolling element ramp can be achieved with a tool or method that can be easily integrated into an existing manufacturing process for rolling element ramp elements. In addition, with the compaction by means of rolling bodies, the tool wear can be kept relatively low when machining the rolling body ramp element. through the

As a side effect, the post-compaction can also reduce tolerances in the area of the rolling element ramp, which occur during sintering or heat treatment, e.g. hardening, due to distortion, etc., i.e. the component accuracy can be increased at least in the functional area of the rolling element ramp element.

The advantages of the invention also occur in particular when, according to one embodiment of the invention, a rolling element ramp element is produced, which has several rolling element ramps as depressions in the first end face, for which a tool is used in which in the tool head one rolling element per rolling element ramp of the rolling element ramp element is pushed over the Tool head surface is held projecting and rollable, the rolling elements are arranged to one another such that one rolling element can be rolled in each case in a rolling element ramp while simultaneously compressing all rolling element ramps of the rolling element ramp element. It is thus possible to compact a rolling element ramp element which has a plurality of rolling element ramps which are designed as indentations, with which not only the effectiveness of the method or the tool can be improved, but also the accuracy of the rolling element ramps can be improved more easily, since the Tool can be supported in several places on Wälzkörperrampenelement. This makes it easier to prevent the tool from tilting.

According to another embodiment variant of the invention, it can be provided that the rolling bodies are arranged in sliding elements, with the sliding elements being held in the tool head. On the one hand, tool wear can be further reduced because the rolling elements in the tool roll with less resistance. This also enables a reduction in the use of energy for the compression of the at least one rolling body ramp. On the other hand, this can also simplify the exchangeability of the rolling bodies after they have worn out, or the tool can also be used for rolling bodies of different sizes, in particular diameters, with a corresponding design of the sliding elements. The difference in diameter can therefore be compensated with the sliding element, so that the tool can be used more universally for differently designed rolling element ramps.

In order to further increase the smooth running of the rolling movement of the rolling bodies, according to one embodiment variant of the invention, it can be provided that the sliding elements and/or the rolling bodies are coated with a friction-reducing coating.

In the preferred embodiment of the invention, the rolling bodies are balls, since their shape means they are less prone to disruption in the process.

According to another embodiment of the invention, the sliding elements can be hollow cylinders, which makes it easier to hold the rolling elements in the tool.

According to a further embodiment of the invention, it can be provided that the rolling body ramp element and/or the tool are adjusted in the axial direction relative to one another in order to generate the pressure of the rolling body on the surface of the rolling body ramp or the rolling bodies on the surfaces of the rolling body ramps.

According to one embodiment variant of the invention, it can be provided that the axial distance between the rolling body ramp element and the surface of the tool head that is not in contact with the rolling body ramp element is reduced during compaction. This means that compaction can be started with a lower initial pressure, which means that the forming of the rolling element ramps and the tool can be processed or used in a way that is gentler on the material.

According to an embodiment variant of the invention, it can be provided that the reduction of the axial distance is carried out in several steps. The material can thus be given more time for the forming in the individual steps, with which, if necessary, also occurring stresses in the material can be better controlled.

Compaction that is gentler on the material can also be achieved if, according to a further embodiment variant, the pivoting movement of the tool and/or rolling body ramp element is carried out with one or more pivoting direction reversals. With this embodiment variant, the material can be given time to relax between the times it is acted upon by the rolling element(s) of the tool, which also allows stresses to be reduced and further compaction is simplified the next time the rolling elements are passed over it.

According to another embodiment variant of the invention, it can be provided that the rolling element ramp or the rolling element ramps are produced with an oversize and this oversize is reduced by the compression. In addition, the degree of compression can also be adjusted via the oversize, in that a smaller oversize is selected for a lower compression, and accordingly a correspondingly higher oversize is used for a higher compression. In other words, at least some of the properties of the rolling body ramp element can also be adapted to the application via the oversize.

The rolling element ramp is preferably not calibrated or the rolling element ramps are not calibrated, but the tolerance setting is carried out exclusively via the compression with the tool. On the one hand, corresponding work steps can be saved in this way. On the other hand, the method and the tool can also be used to produce large rolling element ramp elements that are no longer accessible to calibration.

According to a further embodiment variant of the invention, it can be provided that the compacted edge zone has a layer thickness which is selected from a range of 1 μm to 1 mm. A corresponding adaptation of the rolling resistance can thus be achieved.

According to another embodiment of the invention, the surface of the rolling element ramp or ramps can have a surface roughness with an arithmetic mean roughness value Ra EN ISO 4287 which is at least 10% lower than the arithmetic mean roughness value Ra of the other surfaces of the rolling element ramp that directly adjoin the rolling element ramp or the rolling element ramps. In other words, with the compression, a smoothing of the surface of the rolling element ramp(s) is also made possible, which subsequently enables a wear-reduced operation of the rolling element ramp element.

For a better understanding of the invention, it is explained in more detail with reference to the following figures.

• 1 eine Wälzkörperrampenelement in Ansicht auf die Stirnfläche;
• 2 ein Werkzeug zum Verdichten einer Wälzkörperrampe des Wälzkörperrampenelements in Explosionsdarstellung;
• 3 das Werkzeug nach 2 in Seitenansicht und teilweise geschnitten;
• 4 einen Ausschnitt aus einem Wälzkörperrampenelement in Seitenansicht geschnitten.

They each show in a simplified, schematic representation:

• 1 a ball ramp element as viewed from the face;
• 2 an exploded view of a tool for compacting a ball ramp of the ball ramp element;
• 3 the tool after 2 in side view and partially sectioned;
• 4 cut a section of a rolling body ramp element in side view.

As an introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numbers or the same component designations, it being possible for the disclosures contained throughout the description to be applied to the same parts with the same reference numbers or the same component designations. The position information selected in the description, such as top, bottom, side, etc., is related to the figure directly described and shown and these position information are to be transferred to the new position in the event of a change of position.

All standards cited in this description refer to the latest version of the respective standard at the time of registration, unless otherwise stated.

In the 1 an embodiment variant of a rolling body ramp element 1 is shown in a view of the end face. In particular, the ball ramp element 1 is in the form of a disc and shown in a simplified manner. Depending on the use of the rolling element ramp element 1, this can also have a different appearance, i.e. it does not necessarily have to be cylindrical, as is shown in 1 is shown. The rolling element ramp element 1 can thus also have various attachments, extensions, such as at least one driver element, in order to initiate the rotational movement of the rolling element ramp element 1, or at least one coupling element, in order to enable the rolling element ramp element 1 to be secured against rotation to another component, a toothing, e.g external teeth on the outer circumference or internal teeth on the inner circumference, etc.

It is known that rolling element ramp elements 1 of this type are used as actuators, for example in multi-disc brakes or multi-disc clutches, in order to convert a rotary movement into an axial adjustment movement.

The examples of application mentioned (brake or clutch) are not to be understood as limiting. The rolling element ramp element 1 can also be used for other purposes in which the axial adjustment movement plays a role.

The rolling body ramp element 1 according to the in 1 The exemplary embodiment shown has a disc-shaped, in particular cylindrical, base body 2 . This has a first end face 3 and a second end face 5 formed opposite this in the direction of an axial direction 4 . The latter are better off 3 or 4 evident.

A plurality of rolling element ramps 6 are arranged or formed in the first end face 3 . The rolling element ramps 6 are designed as indentations in the first end face 3 and have a ramp-shaped bottom surface 7 (see FIG 4 ) on which a rolling element, in particular a ball (not shown) rolls during the axial adjustment or rotation of the rolling element ramp element 1 . Since the bottom surface 7 is ramp-shaped, the depth of the rolling element ramps 6 is accordingly smaller in a circumferential direction 8, as is also evident in particular 4 can be seen. Because of this, the width of the rolling element ramps 6 in the circumferential direction 8 can also become smaller, as is shown in particular in FIG 1 is evident. However, the width of the rolling element ramps can also be designed to remain the same.

Furthermore, the length of the rolling element ramps 6 in the circumferential direction 8 is not to be understood as limiting. The rolling element ramps 6 can also be shorter or longer, in particular also extend by an angular value of more than 120°, in that the rolling element ramps 6 are arranged or formed partially one above the other in the radial direction.

The rolling element ramp element 1 preferably has three rolling element ramps 6 . However, only one or two or more than three, for example four, rolling element ramps 6 can be arranged or formed.

The rolling element ramp element 1 can also have a (centrically arranged) opening 9 in order to be able to arrange it, for example, on another element, such as a shaft (not shown).

The rolling body ramp element 1 is preferably produced using a powder metallurgy process. Methods of this type are already well known from the prior art, so that a detailed discussion of the basic features of this method is not necessary. It should only be said that the method essentially comprises the steps of providing a preferably metallic powder, filling the powder into a powder press, pressing the powder to form a green compact, removing the green compact from the powder press, single-stage or multi-stage sintering of the Green compact to the sintered component, optionally post-compacting of the sintered component and optionally hardening of the sintered component. Reference is therefore made to the relevant prior art for these process steps.

It should be noted at this point that instead of a powder-metallurgical process, an additive manufacturing process (3D printing process) can also be used to produce the rolling element ramp element 1 .

The ball ramp element 1 can be cooperatively mounted with another ball ramp element 1, one of these two ball ramp elements 1 being fixed and the second being mounted for axial sliding and rotational movement. At least one of these two rolling body ramp element 1 is designed according to the invention, in particular the axially displaceable and rotatable rolling body ramp element 1. However, both rolling body ramp element 1 of the actuator unit can also be designed according to the invention.

The rolling elements are arranged in the rolling element ramps 6, with two arranged rolling element ramp elements 1 according to the invention, the rolling element ramps 6 being arranged in such a way that the rolling elements roll in rolling element ramps 6 of both rolling element ramp elements 1.

As already stated, balls are preferably used as rolling elements. However, the rolling elements can also have a different shape, for example as rollers, drums, needles, etc. Particularly preferably, only one rolling element is arranged per rolling element ramp 6 or per interacting rolling element ramp 6 of two rolling element ramp elements 1 .

As already explained above, the rolling element ramps 6 are compressed (post-compressed). This densification preferably takes place after the sintering and optionally after the hardening of the rolling element ramp element 1. However, the densification can also take place before the hardening of the rolling element ramp element 1. As stated above leads to the hardening of the rolling element ramp element 1 as part of the method being provided only as an option.

The compaction of the rolling body ramps 6 of a rolling body ramp element 1 with three rolling body ramps 6 will be discussed in more detail below. However, these statements can also be applied to rolling element ramp elements 1 with one of three different numbers of rolling element ramps 6 . The tool for this has to be adapted accordingly.

In the 2 and 3 an embodiment variant of a tool 10 for compacting the rolling element ramps 6 of the rolling element ramp element 1 is shown.

In principle, it is possible within the scope of the invention for the entire rolling body ramp element 1 or only the rolling body ramps 6 to be compressed. If the entire ball ramp element 1 is being compacted, then the ball ramps 6 are preferably more compacted. The tool 10 for compacting the rolling element ramps 6 is used in particular exclusively for compacting the rolling element ramps 6.

The tool 10 has a tool head 11 . The tool head 11 can be connected to a connecting section 12 of the tool 10, in particular can be formed in one piece therewith. The connecting section 12 is used to connect the tool 10 to a tool holder 13 of a processing machine, not shown in more detail, with which the tool 10 can be set in a pivoting movement in a circumferential direction 14 of the tool 10 . As illustrated, the connecting section 12 can be of cylindrical design and have a smaller diameter than the tool head 11. Furthermore, the tool holder can be of frustoconical design, at least in sections. However, it should be pointed out that the connecting section 12 and/or the tool holder 13 can also have a different shape, so that the shape shown in the figures is not to be understood as limiting.

A plurality of rolling bodies 15 are arranged on or on or in the tool head 11 in such a way that they protrude over a tool head surface 16 and can be rolled.

As shown, balls are preferably used as rolling elements. However, the rolling elements 15 can also have a different shape, for example as rollers, barrels, needles, etc., can be designed. Particularly preferably, only one rolling body 15 is arranged in the rolling body ramp element 1 for each rolling body ramp 6 to be compressed. The recordings for the rolling elements 15 are accordingly to be adapted to the shape of the rolling elements.

The rolling bodies 15 can be held in a recess 17 in the tool head 11 . The tool head 11 can also be designed in several parts in order to be able to form the recess 17 tapering in the direction of the tool head surface 16 and still be able to install the rolling elements 15 . For example, the tool head 11 can have a first, in particular disc-shaped, tool head part 18 and a second, in particular disc-shaped tool head part 19 that can be connected thereto (e.g. with screws), the second tool head part 19 having the aforementioned tool head surface 16. The recesses 17 in the second tool head part 19 can have a smaller diameter, a smaller area, than the recesses in the first tool head part 18. Instead of the narrowing of the recesses 17 in the second tool head part 19, they can also be undercut.

For the sake of completeness, it should be mentioned that the recesses 17 in the second tool head part 19 can be formed as openings (through holes, etc.).

The division of the tool head 11 can also be designed differently than shown. For example, a vertical division into several parts of the tool head 11, e.g. the first and/or second tool head part 18, 19, can additionally or alternatively be provided.

It should be mentioned that the rolling elements 15 can also be arranged in recesses 17 which are so large that the rolling elements 15 can be removed from the tool 10 via the tool head surface 16 . In this case, the compression can be carried out, for example, with the rolling elements 15 protruding upwards from the tool head surface 16, so that the rolling element ramp element 1 is placed on the rolling elements 15 from above.

The rolling elements 15 are made of a hard material, for example a tool steel. The term "hard" is to be understood in such a way that the rolling elements 15 have a hardness, at least on the surface, which is greater than or at least the same as the hardness of the rolling element ramp element 1.

According to one embodiment variant of the tool 10, it can be provided that the rolling elements 15 are arranged in receiving elements, the receiving elements in the tool head 11 are held or arranged. According to one embodiment variant, the receiving element can, for example, be designed in the form of a hollow cylinder (bushing shape), in particular if the rolling bodies 15 are balls.

According to an embodiment variant, it can be provided that the receiving elements are at least partially designed as sliding elements 20 . The rolling of the rolling elements 15 can thus be supported or improved.

The sliding elements 20 can consist of a material which, when paired with the material of the rolling body ramp element 1, has a lower coefficient of friction than the pairing of material tool 10 with material rolling element ramp element 1. For example, the sliding element 20 can consist of polytetrafluoroethylene.

In addition or as an alternative to this, according to a further embodiment variant of the tool 10 it can be provided that the sliding elements and/or the rolling elements are coated with a friction-reducing coating. This coating can be a polytetrafluoroethylene coating, a lubricating varnish, etc., for example.

As explained above, the rolling bodies 15 protrude beyond the tool head surface 16. A height 21 of the overhang is preferably dimensioned such that the rolling body ramp element 1 touches the tool 10 during the compaction of the rolling body ramp 6 exclusively with the rolling body ramps 6 to be compacted.

Furthermore, it can be provided that the wall thickness of the receiving elements is adapted to the dimensions of the rolling bodies 15, as has already been explained above, in order to be able to arrange rolling bodies 15 of different sizes in a tool 10. The rolling bodies 15 for a rolling body ramp element 1 preferably have the same shape and the same dimensions. However, it cannot be ruled out that rolling bodies 15 of different sizes and/or provided with different shapes are used for a rolling body ramp element 1 at the same time. For example, it is conceivable that the rolling body ramp element 1 has rolling body ramps 6 with different geometries.

The distribution of the rolling bodies 15 in the tool 10 is preferably dimensioned such that they are distributed evenly over 360°. For example, in the case of three rolling bodies 15, these can be offset from one another at an angle of 120° in the circumferential direction 8. However, if the arrangement of the rolling element ramps 6 in the rolling element ramp element 1 is not designed to be rotationally symmetrical, the arrangement of the rolling elements 15 can also be chosen differently. In any case, an arrangement is preferred with which each rolling element ramp 6 of a rolling element ramp element 1 can be compacted over the entire length in the circumferential direction of the rolling element ramp element 1 with a (clamped) tool 10 without having to change position or change tools.

For the compaction of the rolling body ramp 6, the rolling body ramp element 1 is/are pressed against the rolling bodies 15 and/or the rolling bodies 15 are pressed against the rolling body ramps 6 with the tool 10 and the tool 10 and/or the rolling body ramp element 1 is/are set into a pivoting movement (one Rotational movement offset over an angular section of a circle). The pivoting movement takes place in the circumferential direction 8 over a predefinable pivoting range, in particular over a pivoting range which corresponds to the length of the rolling element ramps 6 in the same direction minus twice the relevant dimension of the rolling elements 15, i.e. in the case of balls minus twice the diameter. The latter takes into account the fact that the rolling elements 15 are not moved beyond the ends of the rolling element ramps 6 in the circumferential direction, but only in the rolling element ramps 6 of the rolling element ramp element 1 that are to be compressed.

During the pivoting movement, the rolling elements 15 roll/roll off on the surface of the rolling element ramps 6 . Due to the pressure applied, pores are compressed or the material deviates, i.e. it is reshaped. With the exception of compression, however, the reshaping does not cause any further change in shape of the rolling body ramp element. After each rolling body ramp 6 (exclusively) one rolling body 15 is present, all rolling body ramps 6 of the rolling body ramp element 1 are treated or compacted simultaneously with one treatment.

In the simplest embodiment of the method, after the tool 10 has been moved to the rolling element ramp element 1 (and/or vice versa), the required contact pressure is built up and then an axial distance 22 between the tool 10, i.e. the tool head surface 16, and the rolling element ramp element 1 is not changed. As a result, the pressure on the rolling body ramps 6 decreases with increasing compaction during processing.

According to one embodiment of the method, however, it can be provided that the axial distance 22 between the rolling body ramp element 1 and the tool head surface 16 that is not in contact with the rolling body ramp element of the work zeugkopfs 11 is reduced during compaction. This can be achieved by a further feed movement of the tool 10 to the rolling body ramp element 1 (and/or vice versa).

As an alternative or in addition to this, the rolling bodies 15 can be spring-loaded in the tool head 11 so that they are pressed outwards by springs. The springs 11 can therefore be arranged below the rolling elements 15 . In this case, the rolling elements 15 can be adjusted relative to the surface of the rolling element ramps 6 during compression due to the spring preload, which means that, compared to the embodiment without springs, there is greater contact pressure of the rolling elements 15 on the rolling element ramps 6 during compression, even without reducing the distance 22 between the Tool head surface 16 and the rolling body ramp element 1 can be achieved. However, this embodiment variant can also be provided in addition to reducing this distance 22 .

The reduction in the axial distance 22 between the tool head surface 16 and the rolling element ramp element 1 can take place continuously during compaction. According to another embodiment variant of the method, the infeed of the tool 10 to the rolling body ramp element 1 (that is, the axial distance 22) can also be changed step by step. The steps (i.e. the changes in distance) can all be the same size or can become smaller with increasing compression of the rolling element ramps 6 (i.e. the change in the axial distance 22).

It can further be provided that the pivoting movement is a single pivoting movement. According to another embodiment variant, however, provision can be made for the pivoting movement to be carried out with one or more reversals of direction, so that each rolling element ramp 6 is traversed several times by a rolling element.

Provision can also be made for the size of the pivoting range to be changed during the entire compression process, with the result that rolling element ramps 6 can be produced which have a different degree of compression over their longitudinal extent (in the circumferential direction).

Provision can be made for the pivoting movement itself to be carried out exclusively with the tool 10 or exclusively with the rolling element ramp element 1 or in the form of a combination of a pivoting movement of the tool 10 and the rolling element ramp element 1 . In the latter case, the tool 10 is pivoted in the opposite direction to the pivoting of the rolling element ramp element 1 .

The extent of the compaction of the rolling element ramps 6 can also be predefined via the material provided in these areas for the compaction. In other words, the rolling element ramp element 1 can be produced in the region of the rolling element ramps 6 with an oversize that can be predefined, with this oversize being reduced, in particular reduced to zero, by the "squeezing" or reshaping of the rolling element ramps 6 during compression. The excess can be between 50 μm and 400 μm, for example.

The rolling element ramps 6 are preferably not calibrated. Calibration is known to be a process step in a sintering process, with which the tolerances of a sintered component are reduced by re-pressing with calibration dies.

A rolling element ramp element 1 can be produced with the method or the tool 10, as is shown, for example, in 1 is shown. Due to the compaction of the rolling element ramps 6, these have a compacted edge zone 23, as shown in FIG 4 evident. In this edge zone 23, which is preferably formed below the entire surface area of the rolling element ramp 6, the rolling element ramp element has an edge zone density of at least 93% of the full density of the material of the rolling element ramp element 1.

In the preferred embodiment, this edge zone 23 has a (maximum) layer thickness 24 that is selected from a range of 1 μm to 1 mm, in particular from a range of 10 μm and 800 μm.

According to a further embodiment variant of the rolling body ramp element 1, the surface of the rolling body ramps 6 can have a surface roughness with an arithmetic mean roughness value Ra EN ISO 4287 which is at least 10%, in particular between 30% and 800%, lower than the arithmetic mean roughness value Ra of the other surfaces of the rolling element ramp element 1 directly adjoining the rolling element ramps 6. This smoothing of the surface of the rolling element ramps 6 can be achieved through the use of rolling elements 15 can be achieved in the tool 10, which have a correspondingly smooth surface.

With the invention, a local post-compaction can be achieved by rolling of rolling bodies 15 in the ball ramps 6 of sintered rolling body ramp elements 1 (in particular ball ramp disks). A density gradient can also be formed in the edge zone 23 . The compression can be done by controlled axial pressing of rolling body ramp element 1 and tool 10. At the same time, the tool 10 and/or the rolling body ramp element 1 rotate in the circumferential direction by a predefinable range of rotation.

Furthermore, the method can be carried out with a lubricating medium between rolling elements 15 and rolling element ramps 6 and/or in several infeed steps and/or alternating directions of rotation.

A steel powder, for example, can be used as the metallic powder. However, other metallic or ceramic powders or mixtures thereof can also be used.

The edge zone density in the edge zone 23 of the rolling element ramps 6 can be more than 7.7 g/cm ³ for a steel powder, for example. This is usually not achievable with a conventional calibration method. It is thus possible to provide rolling element ramp elements 1 which are exposed to high Hertzian pressures during operation, with known multi-ball solutions with a number of balls per rolling element ramp 6 being able to be dispensed with.

The rolling element ramps 6 can be compacted as cold compaction or as hot compaction. In the latter case, the rolling body ramp element 1 is preferably heated to the appropriate temperature.

The exemplary embodiments show or describe possible embodiment variants, it being noted at this point that combinations of the individual embodiment variants with one another are also possible.

Finally, for the sake of order, it should be pointed out that elements in the figures are not necessarily shown to scale for a better understanding of the structure.

Reference List

1

ball ramp element

2

body

3

face

4

axial direction

5

face

6

rolling element ramp

7

floor space

8th

circumferential direction

9

breakthrough

10

Tool

11

tool head

12

connection section

13

tool holder

14

circumferential direction

15

rolling elements

16

tool head surface

17

recess

18

tool head part

19

tool head part

20

sliding element

21

Height

22

Distance

23

edge zone

24

layer thickness

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• AT 521299 A1 [0006]
• AT 522548 A1 [0007]

Non-patent Literature Cited

• DIN EN ISO 4287 [0027, 0077]

Claims (17)

Tool (10) for compacting a rolling element ramp (6) of a rolling element ramp element (1), which has been produced from a powder, in particular a metallic one, and which has a first end face (3) and a second end face (5), and wherein in the first end face (3), the rolling body ramp (6) is designed as a recess, the tool (10) having a tool head (11), characterized in that the tool head (11) has a rolling body (15), the rolling body (15) protrudes over a tool head surface (16) and is held in the tool head (11) so that it can be rolled. tool (10) after claim 1 , characterized in that in the first end face (3) several rolling element ramps (6) are formed as depressions, and in that in the tool head (11) one rolling element (15) per rolling element ramp (6) of the rolling element ramp element (1) over the tool head surface (16 ) is held in a projecting and rollable manner, the rolling elements (15) being arranged in relation to one another in such a way that one rolling element (15) in each case in one rolling element ramp (6) can be rolled off when all the rolling element ramps (6) of the rolling element ramp element (1) are being compressed at the same time. tool (10) after claim 1 or 2 , characterized in that the rolling elements (15) are arranged in sliding elements (20), the sliding elements (20) being held in the tool head (11). tool (10) after claim 3 , characterized in that the sliding elements (20) and / or the rolling bodies (15) are coated with a friction-reducing coating. Tool (10) according to one of Claims 1 until 4 , characterized in that the rolling bodies (15) are balls. Tool (10) according to one of claims 3 until 5 , characterized in that the sliding elements (20) are hollow cylinders. Method for compacting the rolling element ramps (6) of a rolling element ramp element (1), which has been produced from a powder, in particular a metallic one, and which has a first end face (3) and a second end face (5), the first end face (3 ) a rolling element ramp (6) is designed as a depression, a tool (10) with a tool head (11) being used for compacting the rolling element ramp (6), characterized in that a tool (10) is used in which the tool head (11) has a rolling body (15), the rolling body (15) protruding over a tool head surface (16) and being held in the tool head (11) so that it can roll, and this tool (10) with the rolling body (15) on the surface of the rolling body ramp (6) is brought into contact, after which the tool (10) and/or the rolling element ramp element (1) is set in a pivoting movement, so that the rolling element (15) rolls under pressure on the surface of the rolling element ramp (6) and the rolling element ramp ( 6) compressed. procedure after claim 7 , characterized in that a rolling body ramp element (1) is compressed, which has a plurality of rolling body ramps (6) which are designed as depressions, wherein in the tool used (10) in the tool head (11) a plurality of rolling bodies (15) are arranged, with each One rolling element (15) is arranged on each rolling element ramp (6) of the rolling element ramp element (1), the rolling elements (15) protruding over a tool head surface (16) and being held in the tool head (11) such that they can be rolled, the rolling elements (15) being arranged in relation to one another in this way are that one rolling element (15) can be rolled in each rolling element ramp (6) when simultaneously compacting several or all rolling element ramps (6) of the rolling element ramp element (1), and this tool (10) with the rolling elements (15) on the surfaces of the Rolling element ramps (6) is brought into contact. procedure after claim 8 , characterized in that for generating the pressure of the rolling element (15) on the surface of the rolling element ramp (6) or the rolling elements (15) on the surfaces of the rolling element ramps (15), the rolling element ramp element (1) and/or the tool (10) be adjusted relative to each other in the axial direction. procedure after claim 8 or 9 , characterized in that an axial distance (22) between the rolling body ramp element (1) and the surface of the tool head (11) not in contact with the rolling body ramp element (1) is reduced during compaction. procedure after claim 10 , characterized in that the reduction of the axial distance (22) is carried out in several steps. Procedure according to one of Claims 8 until 11 , characterized in that the pivoting movement of the tool (10) and/or rolling body ramp element (1) is carried out with one or more pivoting direction reversals. Procedure according to one of Claims 8 until 12 , characterized in that the rolling element ramp (6) or the rolling element ramps (6) are produced with an oversize and this oversize is reduced by the compression. Procedure according to one of Claims 8 until 13 , characterized in that the rolling element ramp (6) or the rolling element ramps (6) is or are not calibrated. Rolling element ramp element (1), which has been produced from a powder, in particular a metallic one, with a first end face (3) and a second end face (5), with a recessed rolling element ramp (6) or several recessed rolling element ramps in the first end face (3). (6) is or are formed, characterized in that the rolling element ramp (6) or the rolling element ramps (6) has or have a compacted edge zone (23), the edge zone density being at least 93% of the full density of the material of the rolling element ramp element (1). Wälzkörperrampenelement (1) after claim 15 , characterized in that the edge zone (23) has a layer thickness (24) which is selected from a range of 1 µm to 1 mm. Wälzkörperrampenelement (1) after claim 15 or 16 , characterized in that the surface of the rolling element ramp (6) or the rolling element ramps (6) has a surface roughness with an arithmetic mean roughness value Ra according to DIN EN ISO 4287, which is at least 10% lower than the arithmetic mean roughness value Ra of the other, directly to the Rolling body ramp (6) or the rolling body ramps (6) adjoining surfaces of the rolling body ramp element (1).

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