CH717705A1 - Component with a coating. - Google Patents

Abstract

The present invention shows a component (BT), in particular for hydraulic machines and/or components, comprising a base body (GK) and a coating (B) applied to the base body (GK), the coating (B) having a functional layer in at least one partial area (FS) which contains at least one wear-reducing material, the wear-reducing material being in particular lead. It is provided that the wear-reducing material is contained in different weight proportions in at least two areas of the functional layer (FS) extending along a functional surface (FO) and/or along a parallel to the functional surface (FO) of the component (BT).

Description

The present invention relates to a component, in particular for hydraulic machines and/or components, comprising a base body and a coating applied to the base body, the coating comprising a functional layer in at least a partial region. In particular, the surface of the coating, which is referred to below as the functional surface, can be a contact surface.

An application example is the engine cylinder of an axial piston machine, whose functional surface forms a contact surface for the functional surface of the control plate and slides along the contact surface of the control plate in the course of its rotation. According to the prior art, all or part of the functional surface in the contact area is formed by a functional layer either on the engine cylinder or on the control plate. In the pairing of components selected for this example, the functional layer is used for dry lubrication, which is why the functional layer can also be referred to as a sliding layer in such a case.

According to the prior art, functional layers of this type contain significant amounts of lead, which, with regard to the stress caused by frictional forces, is crucial for a functional pairing of components with high operational stability, because the lead contained therein acts as a highly effective solid lubricant for favorable sliding properties between the respective contact surfaces of the two components is used. As is well known, friction reduction also serves to increase the energy efficiency of thrusters and/or to reduce hysteresis in mechanical actuators. Due to legal requirements, however, the lead content of components, especially in the area of hydraulics, must be kept low.

As is well known, the components of hydraulic machines are not only subject to the load of frictional forces. In other cases, the effect to be achieved with a coating is an increase in resistance to other stresses, e.g. high surface pressure, deflection, cavitation, etc.

[0005] Important factors for the specific effectiveness of a coating is the composition of the application material used for the coating from its various starting materials and their proportions by weight; in particular the proportion by weight of the starting material that has the decisive influence on the operational stability. The latter material is referred to in the following text as the wear-reducing material. Because a functional layer can also contain another wear-reducing material than lead. The invention also includes such coatings containing multiple wear reducing materials.

In the case of a coating consisting of a metal alloy, for example a brass alloy, the metals contained therein, such as copper, zinc etc., would be the starting materials. In order to achieve increased resistance of such a coating to frictional forces, for example, lead would be a starting material that has a significant influence on operational stability. In other words, in such a constellation, lead would be the wear-reducing material or one of the wear-reducing materials.

For some of these starting materials and in particular for wear-reducing materials such as lead, it is very advantageous or imperative to limit the amount used. Without claiming to be exhaustive, a restriction on the use of certain starting materials can have the following causes: • Price/general availability • Legislative restrictions • Lack of sustainability in extraction and/or disposal or otherwise critical • Toxicity • Radioactivity • Supply independence

On the other hand, wear-reducing materials such as lead cannot be dispensed with completely, or only with considerable disadvantages.

The object of the present invention is therefore to reduce the amount of wear-reducing material used in a component. Preferably, neither the functionality nor the operational stability should be impaired as a result.

[0010] This object is achieved by components according to claims 1 and 3. Preferred developments of the present invention are the subject matter of the dependent claims.

In the present text, in the context of a coating, including a functional or buffer layer (see below), the term area always refers to a spatial extension along the surface of the base body or along a parallel to the surface of the base body or along the functional surface or meant along a parallel to the functional surface.

In a first aspect, the present invention comprises a component comprising a base body and a coating applied to the base body, the coating comprising a functional layer in at least a partial area, which contains at least one wear-reducing material. The functional layer is subdivided into at least two areas, which differ in that a wear-reducing material contained therein is contained in different proportions by weight.

The inventors of the present invention have recognized that most loads on the coating occur locally with different strengths, and therefore the quantitatively identical requirements for the specific properties of the coating are not present over the entire extent of the coating along the functional surface of a component. Accordingly, according to the first aspect, the present invention provides functional layers with a different proportion by weight of the wear-reducing material, which is required in both areas but should be used in the smallest possible amount, in at least two different areas along the component surface. As a result, the proportion by weight of the wear-reducing material can be reduced where the specific load, which its presence requires but is less pronounced, can be reduced. A high proportion by weight of the wear-reducing material is therefore preferably only used where it is actually required in large quantities or offers highly effective advantages or at least significant advantages.

In one possible embodiment of the present invention, the wear-reducing material is lead.

The component is preferably a component of a hydraulic machine and/or a hydraulic component. Examples of hydraulic machines and/or hydraulic components in which the present invention can be used and is very advantageous are described in more detail below. However, the present invention can also be used in other areas of technology in which functional layers are used that contain at least one wear-reducing material that is required for functionality and/or operational stability, but should be used in the smallest possible amount will.

In a possible first embodiment of the present invention, the functional layer is partially or over its entire extent applied directly to the base body.

In a possible second embodiment of the present invention, the functional layer is applied partially or over its entire extent via a buffer layer on the base body. This means that the buffer layer is arranged in the thickness direction partially or over its entire extent between the surface of the base body and the functional layer, with the buffer layer preferably being arranged directly or via a further layer on the surface of the base body and the functional layer directly or via a further layer is arranged on the surface of the buffer layer.

The wear-reducing material, which must be contained in the functional layer or at least in certain functional layer areas, is preferably contained in the buffer layer with a lower proportion by weight than in the functional layer areas and particularly preferably not contained at all.

With a corresponding composition of the application material and the process control when coating the layers, there can ultimately be a particularly good anchoring between the buffer layer and the functional layer along their common boundary. A boundary between the buffer layer and the functional layer can occur in the thickness direction of a coating, but also when in a common layer of the coating a partial area consists of a buffer layer and another adjoining partial area consists of a functional layer.

In one possible embodiment of the present invention, the buffer layer has a different and in particular higher material hardness than the functional layer. The buffer layer usually aims for better adhesion of the functional layer and is therefore primarily designed for this. In the case of a soft base body, the buffer layer is preferably designed in such a way that it has a high material hardness. On the other hand, the functional layer is optimized to meet the specific requirements for maintaining the operational stability of the functional surface and the crucial aspect that the wear-reducing material or materials are used in the smallest possible amount.

In a second independent aspect of the present invention, it comprises a component consisting of a base body and a coating applied thereto, the coating having a functional layer applied to the base body via a buffer layer in at least one region. In this case, the functional layer contains at least one wear-reducing material, which is preferably contained in the buffer layer with a lower proportion by weight and particularly preferably not at all. A functional surface of the component is formed by the buffer layer in at least a first area and by the functional layer in at least a second area.

Such a functional surface is therefore no longer completely formed by a functional layer, but partially by a functional layer and partially by a buffer layer. A remaining portion of such a functional surface can optionally be formed by the surface of the base body.

In a further possible embodiment of the present invention, there is on a functional surface (i) at least one area in which a buffer layer is applied to the base body and forms the functional surface there and (ii) at least one further area in which on the base body a buffer layer is applied and a functional layer is applied over it, which forms the functional surface there and (iii) optionally there is a further area in which a functional layer is applied to the base body, which forms the functional surface there and (iv) optionally there is at least one further area , in which the functional surface is formed by the base body.

These configurations are also based on the finding of the inventors that most of the loads on the coating occur locally to varying degrees, and therefore not over the entire extent along the component surface, respectively. along the functional surface of the coating, the same quantitative requirements for the properties of the coating are present. Accordingly, the present invention provides, according to the second aspect, to provide a buffer layer in at least one area of the coating, which forms the functional surface there, and to provide a buffer layer with a functional layer applied thereto, which forms the functional surface there, in at least one other area of the coating. In the minimal case of such a coating of a functional surface, the functional surface consists of two different areas along the component surface, a functional layer being provided on the one hand and the buffer layer on the other to form the functional surface. As a result, the proportion by weight of the wear-reducing material can be reduced overall, since the functional surface is formed by the buffer layer where the loads are lower and can already be met by the buffer layer. The functional layer with the wear-reducing material, on the other hand, is preferably only used where the wear-reducing material is actually required.

With the aim of using the wear-reducing material as appropriately as possible, its proportion by weight can vary across the layers of the functional layer and/or along a parallel to the functional surface, including the functional surface itself.

In particular, the buffer layer can have a greater thickness in the area in which it forms the functional surface than in an area in which it serves to connect the functional layer to the base body. The surface of the buffer layer in the region in which it forms the functional surface is therefore preferably level with the surface of the functional layer. Alternatively, the surface of the buffer layer in the area in which it forms the functional surface is mostly level with the surface of the functional layer, but the surface of the buffer layer has at least one depression that can serve as an oil pocket, for example.

The first and the second aspect are initially independently the subject of the present invention. However, the two aspects can also be combined with one another.

In particular, the functional surface can be formed in one area by the buffer layer and in two areas by a functional layer, i.e. in two functional layer areas, with these differing in terms of their different proportion by weight of wear-reducing material.

Preferred embodiments of the present invention, which can be used both in the first aspect and in the second aspect of the present invention, and in their combination, are described in more detail below.

[0030] In general, a functional layer and a buffer layer can each have one or more layers. The different layers that form a functional layer or buffer layer on a component can differ. Without claiming completeness, there can be a difference in the process control with which a respective layer is applied and/or in the composition of the material from which a respective layer of the buffer layer is applied.

[0031] In the case of the functional layer, it results in particular that the proportion by weight of the wear-reducing material can differ in the different layers.

[0032] The information given by the present invention regarding the proportion by weight of the wear-reducing material preferably relates to at least one, in particular the uppermost layer of the buffer layer and/or functional layer. Alternatively or additionally, the information can also relate to the average weight fraction in the material of all layers of the buffer layer or functional layer or of all layers of the buffer layer or functional layer which contain the wear-reducing material. A different proportion by weight is therefore already present when the proportion by weight in at least one of the layers of the functional layer or buffer layer differs from one another, with the proportion by weight preferably differing in the top layer and/or with regard to the average proportion by weight in the material of all layers of the buffer layer or functional layer differs.

The buffer layer and the functional layer each extend at least in sections along a surface or along a parallel to the surface of the base body. They can form a functional surface of the component, at least in sections, or run parallel to such a surface under one or more further layers.

The functional layer areas with a different proportion by weight of the wear-reducing material can be located on the surface of the base body and thereby in areas arranged next to one another. The areas can directly adjoin one another or be separated from one another by further areas.

Layers arranged one on top of the other in the direction of thickness, on the other hand, do not represent different partial areas of a functional layer in the sense of the present invention, even if the material of the layers comprises the wear-reducing material with a different proportion by weight in each case.

The buffer layer is preferably used primarily or the material composition is primarily designed to ensure that the functional layer is anchored with sufficient strength on the component surface and, in the case of soft base bodies, the presence of the buffer layer gives the component increased strength. If a buffer layer optimized in this way also meets the locally prevailing requirements of the loads acting on the functional surface, the functional surface can be formed by the buffer layer in these sections.

The functional layer is preferably used primarily or the material composition is primarily designed to ensure that the functional surface has sufficient operational strength with respect to the loads acting locally on it and, in the case of relative movements, at the same time the friction losses (in terms of efficiency and hysteresis) be kept as low as possible, especially before the corresponding contact surfaces are wetted with oil. It is known that within a certain first operating phase, which takes place after a certain standstill time, the hydraulic components are only sufficiently self-sufficient after a certain period of operation.

The functional layer preferably has an appropriate inherent strength such that it has sufficient operational strength in its thickness direction, e.g. sufficient operational strength against surface pressure and cavitation.

If (locally) a sufficiently strong anchoring of a functional layer on the base body exists or is possible and at the same time the component does not require increased strength through the application of a comparatively hard buffer layer, the functional layer can be applied locally directly to the base body.

In a possible embodiment of the present invention, the wear-reducing material is lead and the buffer layer has a lower lead content than one layer or several layers or all layers of the functional layer or a functional layer area or all functional layer areas. In particular, a buffer layer cannot contain any lead.

In one possible embodiment of the present invention, the functional surface forms a contact surface for another component and the coating as a whole contributes to the functional surface having sufficient operational strength.

In a possible alternative or additional embodiment of the present invention, the functional surface forms a contact surface to a fluid and the coating contributes in its entirety to the fact that the functional surface has sufficient operational strength.

In one possible embodiment of the present invention, the at least two areas of the functional surface of the component form a contact surface for a rotational movement and/or a translational movement of the component relative to a contact surface of another component. The present invention is particularly effective in such sliding processes, since very different loads can exist in the different areas of the contact surface depending on the distance from the axis of rotation and/or depending on the forces acting and/or depending on a normal range of motion.

In one possible embodiment of the present invention, the at least two areas of the functional surface of the component are arranged in different radial, axial and/or circumferential areas of the contact surface with respect to an axis of rotation and/or translational movement.

In one possible embodiment of the present invention, the at least two areas of the functional surface of the component have a different radial distance from an axis of rotation. Due to the different distance to the axis of rotation, the relative speeds and thus the requirements for the contact surface are different in the two areas, which the present invention takes into account.

In a possible embodiment of the present invention, the proportion by weight of the wear-reducing material of the coating is higher at the same distance from the functional surface in a first area with a larger distance to the axis of rotation than in a second area with a smaller distance to the axis of rotation, whereby this principle can of course not only be applied to two, but to several areas. This takes into account the presence of different relative speeds in the different areas.

[0047] If a weight proportion of the wear-reducing material of the coating is mentioned here or below, this preferably refers to the weight proportion of the wear-reducing material in the functional layer or, if this forms the functional surface, in the buffer layer.

In one possible embodiment of the present invention, the component has at least one fluid passage, with the proportion by weight of the wear-reducing material in the coating, which significantly increases the operational strength of the component, being in an area which adjoins the fluid passage and this preferably at least partially surrounds, differs from the proportion by weight of the wear-reducing material in at least one area spaced apart from the fluid passage.

[0049] In this way, the fact can be taken into account that cavitation often occurs in the area of a fluid passage, which stresses the functional surface or the coating in the vicinity of the fluid passage.

In one possible embodiment of the present invention, the proportion by weight of a wear-reducing material contained in the coating, which contributes to the significant increase in dry lubrication, is lower in the functional layer region adjoining the fluid passage than in another functional layer region at a distance from the fluid passage. Area. Due to the greater material hardness due to the lower proportion by weight of such a wear-reducing material in the area adjoining the fluid passage, the coating here is less sensitive to the loads occurring as a result of cavitation.

In a first variant, in the coating of the component area that adjoins the fluid passage and preferably at least partially surrounds it, a lower proportion by weight of such a wear-reducing material can be used, with which a significant increase in dry lubrication can be achieved, but at the same time a reduced fatigue strength against cavitation occurs, be provided than in another area

In a second variant, on the component area which adjoins the fluid passage and preferably at least partially surrounds it, the functional surface can be formed by a buffer layer, over which a functional layer containing a certain weight proportion of the wear-reducing material is placed on the other component area Body is applied. In this second variant, the component has a coating which has a functional surface formed by the buffer layer in the vicinity or at least partially in the vicinity and the functional surface is formed by a functional layer in another area.

In one possible embodiment of the present invention, the functional surface of a component has a first and a second radial area with a different proportion by weight of the wear-reducing material, with a third radial area being arranged between the first and the second radial area, which has at least one fluid passage having.

In a possible first embodiment of the present invention, at least in a first partial area of the third radial area, which adjoins the fluid passage and preferably at least partially surrounds it, the functional surface is formed by a buffer layer, which serves in another area to To connect functional layer with the base body.

In a possible second embodiment of the present invention, at least in a first partial area of the third radial area, which adjoins the fluid passage and preferably at least partially surrounds it, the functional surface is formed by a functional layer that has a different proportion by weight of the wear-reducing material than in at least a second portion of the third radial region spaced from the fluid passage.

In a possible third embodiment of the present invention, at least in a first partial area of the third radial area, which adjoins the fluid passage and preferably at least partially surrounds it, the functional surface formed by a functional layer has a different weight proportion of the wear-reducing material than in the first and/or second radial area.

The second and third configurations can also be combined with one another. In particular, the functional layers can be in the first sub-area of the third radial area, which adjoins the fluid passage and preferably at least partially surrounds it, in the second sub-area of the third radial area spaced apart from the fluid passage, in the first and in the second radial area, respectively be different.

In a possible embodiment of the present invention, such a wear-reducing material is used in the coating or in partial areas of the coating, which causes an increase in the operational strength against cavitation loads. The component has at least one fluid passage, with the proportion by weight of this wear-reducing material differing in a first and a second functional layer area, although both adjoin the fluid passage and preferably at least partially surround it. According to the invention, a comparatively high proportion of the wear-reducing material is used in a functional layer area where a particularly high suction effect, i.e. a comparatively strong negative pressure, occurs when the fluid passage is intended to be flowed through, i.e. the device in which the component with the coating considered here is located in operation.

The higher proportion by weight of the wear-reducing material in a first functional layer area, which forms such a contact area with a partial area of the fluid where the fluid can have a particularly strong negative pressure, contributes to the component being less susceptible to cavitation loads . According to the invention, the second functional layer area, which also adjoins the fluid passage and preferably at least partially surrounds it and consequently also forms a contact area with a partial area of the fluid, contains a lower proportion by weight of the wear-reducing material if the negative pressure of the fluid there is lower than in the contact area of the fluid to the first functional layer area. If the design is correct, a certain amount of wear-reducing material can be saved for the second functional layer area without the risk of an increased risk of such cavitation damage occurring, which is crucial for operational stability.

If the local influencing variables, in particular the pressure conditions, are known as a result of flow simulations, component tests, etc. - at least to a certain degree of accuracy - the basic principle according to the invention can be used to the full by exploiting the associated advantages, namely to create an additional corridor in which an optimization between (i) an increase in the fatigue strength of the component and (ii) a reduction in the amount of wear-reducing material used.

[0061] Certain components have indentations and/or fluid passages that extend comparatively widely over the functional surface. This can result in the surface pressure leading to a load in the vicinity of such a depression or such a breakthrough, which must be dominant or have a significant influence on the coating, so that the component or the coating meets the required fatigue strength.

In one possible embodiment of the present invention, the component has at least one depression and/or at least one fluid passage, with the proportion by weight of the wear-reducing material in the coating, which significantly increases the operational strength of the component, being in a range which adjoins the fluid passage and preferably at least partially surrounds it, differs from the proportion by weight of the wear-reducing material in at least one region spaced apart from the depression or from the fluid passage.

In this way, account can be taken of the fact that surface pressure often occurs in the vicinity of a depression or a fluid passage, which stresses the functional surface or the coating in the vicinity of the fluid passage.

In one possible embodiment of the present invention, the proportion by weight of a wear-reducing material contained in the coating, which contributes to the significant increase in dry lubrication, is lower in the functional layer area adjoining the depression or the fluid passage than in another of the recess or the functional layer area spaced apart from the fluid passage. Due to the greater material hardness at the recess or the area adjoining the fluid passage due to the lower proportion by weight of such a wear-reducing material, the coating here is less sensitive to the loads occurring as a result of the surface pressure.

In a first variant, a lower proportion by weight of such a wear-reducing material can be used in the coating of the component area that adjoins the depression or the fluid passage and preferably at least partially surrounds it, with which a significant increase in dry lubrication can be achieved can, but at the same time a reduced fatigue strength against surface pressure occurs, be provided than in another area

In a second variant, the functional surface can be formed by a buffer layer on the component area which adjoins the depression or the fluid passage and preferably at least partially surrounds it, which in another component area contains a wear-reducing material to a certain extent by weight containing functional layer is formed on the base body. In this second variant, the component has a coating which has a functional surface formed by the buffer layer in the vicinity or at least partially in the vicinity and the functional surface is formed by a functional layer in another area.

In one possible embodiment of the present invention, the functional surface of a component has a first and a second radial area with a different proportion by weight of the wear-reducing material, with a third radial area being arranged between the first and the second radial area, which has at least one depression and/or has at least one fluid passage.

In a possible first embodiment of the present invention, the functional surface is formed by a buffer layer, at least in a first partial area of the third radial area, which adjoins the depression or the fluid passage and preferably at least partially surrounds it Area serves to connect a functional layer with the base body.

In a possible second embodiment of the present invention, the functional surface is formed by a functional layer, at least in a first partial region of the third radial region, which adjoins the depression or the fluid passage and preferably at least partially surrounds it of the wear-reducing material than in at least a second portion of the third radial region spaced apart from the fluid passage.

In a possible third embodiment of the present invention, at least in a first partial area of the third radial area, which adjoins the recess or the fluid passage and preferably at least partially surrounds it, the functional surface formed by a functional layer has a different proportion by weight of the wear-reducing Material than in the first and / or second radial region.

The second and third configurations can also be combined with one another. In particular, the functional layers can be in the first partial area of the third radial area, which adjoins the depression or the fluid passage and preferably at least partially surrounds it, in the second partial area of the third radial area spaced apart from the depression or the fluid passage, be different in each case in the first and in the second radial region

In the above-mentioned configurations, the coating or functional surface can be arranged in particular on an engine cylinder, a control plate, a piston, a piston liner, a swash plate and/or the sliding surface of a sliding shoe, so that the component is in particular a engine cylinder, a control plate, a piston, a swash plate and/or a sliding shoe. Such a coating as described in the previous text is preferably present on the functional surface of the component. the functional surface is formed by such a coating.

In the configurations mentioned above, the coating or functional surface can in particular represent a contact surface for a rotational movement through a limited angular range, i.e. a pivoting movement, or for a rotational movement for an unlimited angular range and in particular for a rotational movement.

[0074] Furthermore, the coating or functional surface can represent a contact surface for a linear movement or superposition of rotation and linear movement.

In a possible further embodiment of the present invention, the functional surface of the first component forms a contact surface for a second component, which executes a pivoting movement and/or linear movement relative to the first component.

[0076] For example, the contact surface of the first component can be the contact surface of a plain bearing, for example the contact surface of a swivel cradle or the guide surface of an engine or control piston. The coating according to the invention can be arranged on the static and/or on the moving component.

[0077] Since the transverse forces or the normal forces usually act on components in such a way that they do not act in the center but offset in the contact surfaces and/or there is an additional deflection of components, there is also a locally different load for contact surfaces that ( i) serve in their function as a support surface for another component, which performs a relative pivoting movement or a relative rotational movement or (ii) serve in their function as a guide surface for a relative linear movement for another component.

In one possible embodiment of the present invention, the contact surface is formed at least partially from a coating which comprises at least two areas arranged next to one another in the axial or circumferential direction, in which the wear-reducing material is contained in different proportions by weight.

[0079] These at least two coating areas can have a functional surface which is formed from a functional layer area in which the wear-reducing material is contained in different weight proportions. Alternatively or additionally, the functional surface can be formed by a buffer layer in at least one partial area and by a functional layer in at least one other partial area.

In particular, the locally different loads acting on the contact surface, which are caused by transverse forces and/or deflections, can be taken into account. Alternatively or in addition, the loads that are caused in a specific range of motion can be taken into account; e.g. a preferred resp. common range of motion and/or the position of maximum loading.

In particular, in a first area of the contact surface, in which a greater load acts as a result of transverse forces and/or deflection, the proportion by weight of the wear-reducing material in the coating can be distributed along the surface of the base body or along a line parallel to the surface of the base body, i.e. along the functional surface or along a parallel of the functional surface - be higher than in a second area that is subject to lower loads.

Furthermore, in a first area of the contact surface, in which such loads are higher in a normal position of the movable component, the proportion by weight of the wear-reducing material in the coating there can be higher than in a second area, on which lower loads are applied in a normal position influence

The contact surface of the component can be, in particular, the bearing surface of a rotation axis (e.g. the rotation axis of a drive shaft) or pivot axis (e.g. the pin of a pivoting cradle) or a guide surface of another component (e.g. an engine or control piston), that performs a relative linear movement.

[0084] Equally, the contact surface can be a partial area of the surface of the moving component, such as a drive shaft, a pivoting cradle, an engine or control piston, etc.

A possible further embodiment of the present invention relates to the functional surfaces of a ball head connection. The coating according to the invention can be applied to the ball head and/or to the surface in the spherical cap or form at least a part of the surface of the ball head and/or a part of the surface of the spherical cap.

In one possible embodiment of the present invention, the contact surface having the shape of a spherical head or a spherical cap comprises, with respect to an imaginary axis passing through such a body, at least two regions arranged radially next to one another, which are each provided with a coating, with the two coating distinguish areas.

In one possible embodiment, there are at least two coating areas in which a wear-reducing material is present in different proportions by weight.

In particular, this allows different bearing forces and/or loads to be taken into account, which are caused by the distance from an axis of rotation, the locally present lateral forces, the deflection and/or a preferred range of movement.

Furthermore, in a first area of a contact surface of a ball head connection, in which such loads are higher in a normal position or in a narrow, mainly occurring range of movement of the movable component, the proportion by weight of the wear-reducing material in the coating there can be higher than in a second area Area exposed to lower loads in a normal position.

The spherical head connection, which has a contact surface equipped with a coating according to the invention, can in particular be a spherical head connection between an engine piston and a sliding block, i.e. an engine piston-sliding block unit.

If the ball head connection according to the invention relates to the connection between an engine piston and a sliding shoe, the coating areas - i.e. partial areas with a respective identical coating - preferably extend over areas that are rotationally symmetrical to the central axis of the engine piston or the sliding shoe. The background to this is that a sliding shoe rotates around its own axis of rotation.

In one possible embodiment of the present invention, the component has at least three coating areas, each with a different proportion by weight of the wear-reducing material. In particular, the component can have three areas, in each of which a functional layer with a different proportion by weight of the wear-reducing material is provided. As a result, the locally different loads can be taken into account in an even more targeted manner. This wear-reducing material is preferably lead.

In one possible embodiment of the present invention, the three coating areas have different radial distances from an axis and/or are arranged in different axial or circumferential sections of a contact surface.

In one possible embodiment of the present invention, the at least two or three coating areas directly adjoin one another.

In one possible embodiment of the present invention, the two or three coating areas form a common contact surface, i.e. together serve to contact another component.

In one possible embodiment of the present invention, the component has at least three different coating areas, two of which have a different proportion by weight of the wear-reducing material, while the third area has a different wear-reducing material.

In one possible embodiment of the present invention, an additional running-in layer is applied at least to a partial area of the functional surface.

The running-in layer is intended to even out any unevenness on the functional surface, in particular on the surface of the actual coating, and is largely rubbed off during running-in and/or at least partially displaced along the component surface.

In one possible embodiment of the present invention, the running-in layer covers the functional layer in the at least two areas.

In one possible embodiment of the present invention, the thickness of the running-in layer is less than the thickness of the functional layer.

In one possible embodiment of the present invention, the thickness of the running-in layer after application and before the running-in process is in the range from 0.05 to 0.2 millimeters, preferably from 0.05 to 0.14 millimeters and more preferably from 0. 05 to 0.075 millimeters.

In one possible embodiment of the present invention, the running-in layer has a higher proportion by weight of the wear-reducing material than the functional layer in the at least two areas, with the wear-reducing material mentioned in connection with the running-in layer being lead in particular.

In a possible embodiment of the present invention, the proportion by weight of the wear-reducing material in the two coating areas is between 0.1 wt% and 30 wt%, preferably between 0.1 wt% and 20 wt% (N.B.: wt% = weight percent ).

In one possible embodiment of the present invention, the proportion by weight of the wear-reducing material in the two coating areas differs by at least 0.5% by weight, preferably by at least 2% by weight, more preferably by at least 5% by weight.

In one possible embodiment of the present invention, one, several or all of the functional layer areas and/or buffer layer areas comprise at least one layer made of a copper-zinc alloy or a copper-zinc-based alloy with other alloying components if necessary consists.

The copper content is preferably between 50% and 70%, more preferably between 55% and 65% and/or the zinc content is between 25% and 45%, preferably between 30% and 40%.

In one possible embodiment of the present invention, all layers of the functional layer areas and/or buffer layer areas consist of a copper-zinc alloy or copper-zinc base alloy with other alloying components, if necessary, in particular of an alloy as mentioned above was described.

In one possible embodiment of the present invention, the at least two different components of the coating extend over the thickness of the coating.

In one possible embodiment of the present invention, the functional surface and/or coating has at least two different material hardnesses in at least two different areas.

In one possible embodiment of the present invention, the coating applied to the base body has two different degrees of hardness over the thickness of the coating, at least in a partial area.

In one possible embodiment of the present invention, it is provided that there is a monotonously decreasing material hardness profile, starting from the base body in the direction of the functional surface, or that there is an almost constant hardness profile within the coating.

In a possible embodiment of the present invention, it is provided that there is a monotonously increasing material hardness profile starting from the base body in the direction of the functional surface via the coating or there can be a decreasing material hardness profile within the coating towards the functional surface.

In the case of components of the coating, i.e. (i) the entire buffer layer, a layer of the buffer layer or a region of the buffer layer extending along a parallel to the component surface or along the component surface, or (ii) the entire functional layer, a layer of the functional layer or a region of the functional layer which is made of a bronze-like alloy and which extends along a parallel to the component surface or along the component surface, the weight ratio (Cu/Sn) between copper and tin is preferably in a range from 5 to 15 and particularly preferably in a range of 7 to 13.5.

In the case of components of the coating, i.e. (i) the entire buffer layer, at least one layer of the buffer layer or at least one part of the buffer layer extending along a parallel line of the component surface or along the component surface or the (ii) entire functional layer, at least one layer of the functional layer or at least a partial area of the functional layer that extends along a parallel to the component surface or along the component surface and consists of a brass-like alloy, the proportion by weight of zinc is between 25% and 40% and/or the proportion by weight of copper is between 50% % to 70%.

In one possible embodiment of the present invention, it is provided that the at least one buffer layer, e.g. at least one layer of the buffer layer and/or at least one partial region of the buffer layer extending along the component surface and/or along a parallel line of the component surface, consists of a chromium-nickel base alloy or a chromium-nickel alloy (e.g. Cr[20-23] Ni58...) or a copper-tin base alloy or copper-tin alloy (e.g. Cu80Sn12Ni2...).

In one possible embodiment of the present invention, it is provided that the locally present and/or the partial weight proportion of the wear-reducing material in the coating, depending on the local relative speed and/or the partial range of the relative speed of the component in its contact area, becomes one other component is.

In a possible embodiment of the present invention, it is provided that the locally present and/or the partially present weight proportion of the wear-reducing material in the coating depends on (i) the local type of load (in particular the friction (actually the normal force, which causes friction), surface pressure (actually the normal force that causes surface pressure), cavitation loads and other applied forces that lead, for example, to a deflection of a component, and/or (ii) the area of such a partial load.

In one possible embodiment of the present invention, it is provided that the buffer layer does not contain any lead.

In a possible embodiment of the present invention, it is provided that the base body is made of one or more of the following materials: made of hardenable or non-hardenable steel cast material made of an aluminum alloy made of soft metal or a soft metal alloy, e.g. bronze, brass, ... made of plastic, in particular of polymer plastic

The base body can be designed as a forged part or a sintered part.

Irrespective of the starting material and the initial shape of the blank, recesses for the application of the coating and any specific surface structures can already be included or prepared before a first layer of a coating is applied or. before the raw part is conditioned immediately prior to application.

In one possible embodiment of the present invention, it is a component of an axial piston machine, in particular an engine cylinder, a control plate, an engine piston, a cylinder liner, a sliding shoe, a pivot cradle bearing, a drive shaft bearing, an actuating piston guide, etc.

The present invention comprises in particular an engine cylinder or a control plate, the functional surface of which is coated at least in a partial area, with at least two openings penetrating the coating being located in this partial area, with the functional surface being formed by at least two functional layer areas, each of which contain the wear-reducing material in a different proportion by weight.

In one possible embodiment of the present invention, the engine cylinder or the control plate has at least one preferably continuous coating and particularly preferably at least one functional layer, with the functional layer enclosing all such openings which, with a corresponding rotational position of the engine cylinder, are part of an oil connection between the engine and the tank return and/or between the engine and the high-pressure outlet, and is composed of an outer, middle and inner web area, with the proportion by weight of the wear-reducing material on the functional surface increasing monotonically or strictly monotonically with increasing distance from the engine axis.

In one possible embodiment of the present invention, the engine cylinder or the control plate has at least one preferably continuous functional layer, with the functional layer enclosing all such openings which, with a corresponding rotational position of the engine cylinder, are part of an oil connection between the engine and the tank and/or between the engine and the high-pressure outlet, and is composed of an outer, middle and inner land area, the wear-reducing material being lead and the lead content in the functional layer, starting from an area enclosing the pitch circle circumference, being monotonous or severe with decreasing distance to the center increases monotonously and/or increases monotonically or strictly monotonically, starting from an area enclosing the circumference of the pitch circle, with increasing distance from the center point. In a possible embodiment of the present invention, the functional surface of the engine cylinder or the control plate is formed in at least a partial area by a buffer layer.

In a possible embodiment of the present invention, there is at least one opening in the coating, which is exposed at least in the outward direction of the functional surface and the opening within the coating is completely surrounded by the buffer layer.

In one possible embodiment of the present invention, it is a component of an internal gear unit, in particular an internal rotor or external rotor, a component of a radial or in-line piston machine, in particular a displacement piston, a bushing, a camshaft or a drive shaft bearing, etc., or a component a ball joint connection of a hydraulic machine.

The present invention also includes a hydraulic displacement unit and/or another hydraulic component, such as a hydraulic valve, and/or a device with at least one such component as described above.

In a first variant of the present invention, the proportion by weight of the wear-reducing material in a respective functional layer area is constant in the component and differs only between different functional layer areas. In a first variant, there is a first functional layer area on which the proportion by weight of the wear-reducing material on the functional surface is different than on the functional surface of the second functional layer area.

In a second variant of the present invention, the proportion by weight of the wear-reducing material in the functional layer of the component varies continuously along the functional surface and/or along a parallel to the functional surface. Such a variation in the proportion by weight of the wear-reducing material preferably runs continuously, in principle in the sense in which this term is used in mathematics. It is clear to the person skilled in the art that this can only be a tentative characteristic of the nature of the functional layer, because when the coating cools down, material inhomogeneities occur due to different melting temperatures and different adhesive forces between the various alloy components, even if before application alloy melt that is still in liquid form is completely homogeneous.

The present invention also includes a method for producing a component, as described above, wherein a functional layer area is applied in at least two areas of the component, the proportion by weight of the wear-reducing material being different.

In a first variant, a different, already completely premixed application material can be applied in each case to produce the first and the second functional layer region.

In a second variant, the wear-reducing material can be added to the application material in different doses, depending on the area of the functional layer.

In a first embodiment, the wear-reducing material is in the form of a strip and in particular in the form of a wire. Its weight can then be reduced to the current operating point via the feed rate as a function of the function layer location. be introduced at the current melting point.

In a second embodiment, the wear-reducing material is present in the form of particles, which are applied to the functional layer in different amounts, and in particular are shot onto it. The particles each have a dosed kinetic energy, respectively, upon impact on the resulting functional layer. on the base body or on the buffer layer causes the particles to melt, whereby approximately continuous changes in the proportion by weight of the wear-reducing material can be achieved along the resulting functional surface or along a respective resulting layer of the functional layer.

The second variant and in particular its second embodiment allow a certain approximation for achieving a functional layer in which the proportion by weight of the wear-reducing material contained therein changes continuously. Based on such an idealization, a coating of the functional surface of an engine cylinder would actually be possible, for example, whose functional surface has a strictly monotonously increasing weight proportion of a wear-reducing material with increasing distance from the axis of rotation.

[0137] Due to the different melting temperatures and different adhesive forces between the various alloy components, a functional layer area cannot be created in a microscopic view, in which a wear-reducing material is present in a constant proportion by weight.

In a macroscopic view that is practicable for the application, corresponding coatings can be achieved in which there is a continuously changing weight proportion of the wear-reducing material and coating areas are created that each have a constant weight proportion of the wear-reducing material.

The present invention will now be described in more detail using exemplary embodiments and drawings.

1 shows a schematic representation of a component according to the first and the second aspect of the present invention in comparison to components according to the prior art, FIG a first embodiment of the first aspect of the present invention according to the first aspect of the present invention, FIG. 5 shows the course of the lead content as a function of the radius in two variants of the exemplary embodiment shown in FIG. 4, FIG the invention, Fig. 7 shows the course of the lead content in a sectional view in a variant with a running-in layer, Fig. 8 shows a schematic illustration of an embodiment of the second aspect of the present invention in a sectional view, Fig. 9 shows a sectional view through a first embodiment of an engine cylinder or a control plate according to the second aspect of the present invention, Fig. 10 exemplary embodiments of the two functional surfaces of a control plate in which the present invention can be used, Fig. 11 an exemplary embodiment of an engine cylinder or a control plate in which the present invention can be used 12 shows another embodiment of an engine cylinder or control plate with which the present invention can be used. FIG. 13 shows an embodiment of an engine cylinder with which the present invention can be used, in a plan view and a sectional view, Fig. 14 an exemplary embodiment of an axial piston machine in which the present invention can be used, in a sectional view, Fig. 15 diagrams of the material hardness profile in the thickness direction, i.e. in the direction of increasing penetration depth of the component in exemplary embodiments of the present invention, Fig. 16 is a plan view of a first embodiment of a pivoting cradle bearing according to the first aspect of the present invention, FIG. 17 is a perspective view of a pivoting cradle with bearing shells, in which the configuration according to FIG. 16 can be used, FIG. 18 is a schematic view of the flank 16 according to the first aspect of the present invention, FIG. 19 (left) a view of a mounted swivel cradle from a different perspective than in FIG. 17, 19b (right) a schematic view of the flank of an L 16, Fig. 20a shows a schematic sectional view through a first embodiment of an axial guide of an actuating piston according to the first aspect of the present invention, Fig. 20b shows a schematic sectional view of the guided actuating piston according to Fig 20a with the effect of the reaction force exerted by the pivot cradle on actuating pistons exaggerated for purposes of illustration, Fig. 21 a sectional view through a first embodiment of a ball and socket connection between an engine piston and a sliding shoe according to the first aspect of the present invention, Fig. 22 (left) a Sectional view through a sliding shoe according to Fig. 21 according to the first aspect of the present invention, Fig. 22b (right) Top view of the running surface of a sliding shoe according to Fig. 22 (left), Fig. 23a Sectional views of an engine piston sliding shoe guided in a bushing -units - ge according to the first aspect of the present invention - in three different axial positions, Fig. 23b schematic cross-section through a bushing - according to the first aspect of the present invention - which can be used in an arrangement of Fig. 23a for guiding the engine piston, Fig. 24 a sectional view through an embodiment of an in-line piston pump in which the present invention can be used, FIG. 25 shows the embodiment shown in FIG. 24 in an axial section, . 26 shows schematic sectional views of a displacer guided via a camshaft, FIG. 27 and a schematic sectional view of a guided displacer according to FIG.

1 shows the layer structure of two components BT according to the prior art on the left. Above is a component BT with a base body GK and a coating B in the form of a functional layer FS applied to the base body GK by means of a buffer layer PS, and below is a component BT with a base body GK and a coating B in the form of one applied directly to the base body GK Functional layer FS. In both cases, the functional surface FO is formed by the functional layer FS, which has the same composition over its entire extent.

Exemplary embodiments of five different layer structures of components according to the present invention are shown on the right.

The exemplary embodiment 1 at the top left shows a component BT according to the first aspect of the present invention, in which different functional layers are applied in two areas on the base body GK. Such different functional layers are referred to as functional layer areas (F1 to Fi) in the following text.

A functional layer area F1 preferably has at least one wear-reducing material M and extends along the surface of a base body GK or along a parallel to the surface of the base body GK or along the functional surface FO or along a parallel to the functional surface FO. A functional layer area F1 preferably contains at least one wear-reducing material M. The wear-reducing material M is evenly distributed within a functional layer area F1—insofar as this is practicable in terms of production technology. If a functional layer area F1 contains several wear-reducing materials M, M', M"... then within a functional layer area (F1) - as far as it is practicable in terms of production technology - each wear-reducing material M, M', M" contained therein is.. .equally distributed.

The functional layer areas F1 and F2 shown in FIG. 1 each contain the same wear-reducing material M, which is contained in the two functional layer areas FS1 and FS2 in different proportions by weight.

The wear-reducing material M is a material which is required for the functionality and/or the operational stability of the component or the device in which such a component BT is used, but may only be used in the smallest possible amount.

In this exemplary embodiment, the functional surface FO of the component BT is therefore formed by the two functional layer regions FS1 and FS2, which extend along the functional surface FO and have different proportions by weight of the wear-reducing material M.

By covering this requirement for the functional layer FS of an area in which a smaller amount of the wear-reducing material M is sufficient, but still using less than for another area in which sufficient operational strength and/or other Reasons a higher amount of wear-reducing material M is required. In this way, the total amount of wear-reducing material M to be used can be reduced compared to a coating B corresponding to the prior art without functional disadvantages. This principle according to the invention can be cascaded in that instead of a subdivision into only two functional layer areas F1 and F2, a subdivision into a larger number of further functional layer areas F1, F2 to Fi is carried out. If, for a good reason, e.g. legislative restrictions, the total amount of wear-reducing material M desired from a purely technical point of view cannot be used, the principle according to the invention allows a significantly better utilization of the limited total amount of wear-reducing material M. In general terms, the first aspect of the invention allows the creation of a corridor in which an optimization between (i) an increase in operational stability and (ii) a reduction in the application rate of the wear-reducing material M, the application rate of which should/must be kept as low as possible, can be undertaken.

In the exemplary embodiment, the two functional layer regions F1 and F2 are each applied directly to the base body GK, but could also be applied to the base body GK via a buffer layer PS.

The exemplary embodiment 2 at the top right shows a component BT according to the second aspect of the present invention, in which a functional layer FS1 is applied to the base body GK in a first area by means of a buffer layer PS, the buffer layer PS being the functional surface in a second area FO forms. The functional surface FO is therefore formed in the first area by the functional layer area F1 and in the second area by the buffer layer PS. The composition of the buffer layer PS and/or the method with which the buffer layer is applied can be identical in the first and in the second area, although the buffer layer PS in the first area forms the surface on which the functional layer area FS1 is applied is, whereas the buffer layer PS forms the functional surface FO in the second area.

In this exemplary embodiment, the contact area between the functional layer area FS1 and the buffer layer PS is increased in that they not only adjoin one another along a line parallel to the surface of the base body, but also over at least one other area. This results in a particularly strong anchoring of the functional layer FS, because the buffer layer PS is designed in such a way that it causes the functional layer FS to adhere particularly strongly.

The embodiment 3 in the middle above shows a component BT, in which both the first and the second aspect of the present invention is realized.

In particular, by means of a buffer layer PS, a functional layer area F1 is applied to the base body GK in a first partial area and a functional layer area F2 is applied in a second partial area, with the wear-reducing material M being contained in both, but in a different proportion by weight . In a third sub-area, the functional surface FO is formed by the buffer layer PS. In this exemplary embodiment, the contact area between the respective functional layer areas F1, F2 and the buffer layer PS is increased in that they not only adjoin one another along a line parallel to the surface of the base body, but also over at least one additional area.

The exemplary embodiment 1′ at the bottom left again shows a component BT according to the first aspect of the present invention, in which two functional layer regions F1 and F2 are applied to the base body GK, each of which contains a wear-reducing material M in a different proportion by weight. Between the two functional layer areas F1 and F2 there is a third functional layer area F3, which, however, does not contain the wear-reducing material M.

The exemplary embodiment 2 'bottom right again shows a component BT according to the second aspect of the present invention, in which a functional layer area FS1 is applied to the base body GK in a first partial area by means of a buffer layer PS, the buffer layer PS in a second and a third area forms the functional surface FO. The buffer layer PS applied in the second and third partial area surrounds the functional layer area FS1 applied in the first partial area. Such an embodiment expands the contact area between the functional layer area FS1 and the buffer layer PS to at least three areas.

[0156] Furthermore, exemplary embodiments with more than two functional layer areas are conceivable, which contain the wear-reducing material M, but each in different proportions by weight.

In a possible embodiment of the present invention, the various functional layer areas (F1 to F1) always contain a specific quantity of the wear-reducing material M, but in different weight proportions. In the context of the present invention, the buffer layer PS is preferably free of the wear-reducing material M. As the exemplary embodiment 1′ shows, a functional layer area (in FIG. 1′ referred to as F3) can, however, also be free of the wear-reducing material in certain configurations be M.

In the context of the present invention, the functional surface FO of a component BT can in particular be a contact surface with a contact surface of an adjacent component BT′ or a contact area with a fluid.

[0159] Within the scope of the present invention, a functional layer FS and a buffer layer PS can each be designed in one layer or in multiple layers.

Steel (alloyed, unalloyed), cast iron or an Al alloy is used in particular as the material for the base body GK. Other conceivable materials for the base body GK are soft metals or soft metal alloys such as brass, bronze, etc. or plastic, especially a polymer plastic.

The buffer layer PS can be made, for example, from a chromium-nickel base alloy or a chromium-nickel alloy (e.g. Cr[20-23] Ni58...) or from a copper-tin base alloy or copper-tin alloy ( e.g. Cu80Sn12Ni2...). The functional layer FS or the functional layer areas (F1 to Fi) can also be made of a chromium-nickel base alloy or a chromium-nickel alloy (e.g. Cr[20-23] Ni58...) or of a copper-tin base alloy or copper-tin alloy (e.g. Cu80Sn12Ni2...) and also contain lead.

Alternatively, the functional layer FN or functional layer areas (F1 to Fi) consist of a copper-zinc alloy or a copper-zinc-based alloy, each of which preferably has a copper content of between 50% and 70% and particularly preferably between 55% and 65% and alternatively or additionally preferably each have a zinc content between 25% to 45% and particularly preferably between 30% and 40%. The alloys or base alloys can each additionally contain lead as a wear-reducing material.

In particular, these material compositions can be selected for a functional layer FN, which serve to improve the sliding properties and thus reduce the wear caused by frictional forces.

In the context of the present invention, the proportion by weight of the wear-reducing material M contained in the functional layer FN is preferably between 0.1% by weight and 20% by weight, in particular between 0.2% by weight and 10% by weight. The size specifications apply in particular if the wear-reducing material contained in the functional layer FN is lead, which is used to improve the sliding properties of the contact surface of the component BT.

The quantitative ratio of all other starting materials of the functional layer FS can remain the same for all functional layer areas or can also vary.

Within the scope of the first aspect, the functional layer FS can be divided into two separate areas, i.e. a functional layer area F1 and a functional layer area F2, and the proportion by weight of the material M, which is used to significantly reduce wear, is within a respective functional layer Area F1, F2 constant, whereas said weight percentage differs between the areas along the functional surface FO and/or along a parallel to the functional surface FO. Alternatively or additionally, said weight fraction within a section of a functional layer FS along the functional surface FO and/or along a parallel to the functional surface FO and/or along the surface of the base body GK and/or along a parallel to the surface of the base body GK and/or along the surface of the buffer layer PS and/or along a parallel line of the surface of the buffer layer PS on which the section or part of the section of the functional layer FS is applied, vary continuously at least in partial areas.

It is known to the person skilled in the art that when an alloy cools down from a homogeneous melt, a truly homogeneous structure does not result. In this respect, the term "continuous" in its analogous meaning as in mathematics merely represents an idealization in this context, which is useful for explanation.

[0168] A region of the surface of the base body GK, which is coated with the buffer layer PS or a functional layer FS, can be flat, spherical, ball-shaped, cylindrical or part-cylindrical, for example.

The present invention can be used in particular in the field of hydraulics, i.e. in particular in the case of components of hydraulic machines such as hydraulic pumps and/or motors or hydraulic actuators such as hydraulic cylinders and/or other hydraulic components such as valves and regulators etc.

Examples without claiming to be complete for components from the field of hydraulic machines with correspondingly shaped surfaces whose coating according to the invention makes sense under the appropriate framework conditions are: flat, plan engine cylinder (rotating functional surface with non-rotating control plate), control plate (fixed functional surface with rotating engine cylinder ), sliding shoe (functional surface moved in translation over the sliding surface of the swash plate), sliding shoe with functional surface on the back in connection with the back plate, housing & intermediate flange each with fixed functional surface with connection with the internal and external rotor of the internal gear pump, sliding block (functional surface on the side of the sliding block in connection with the adjusting piston, liner blank made of strip material, e.g. for spherical (concave or convex) drive shaft bearing, engine cylinder (rotating functional surface with non-rotating control plate), St Eur plate (fixed functional surface with rotating engine cylinder), ball-joint connection sliding shoe & engine piston, retraction ball & retraction plate, pivoting cradle & actuating lever cylindrical with inner coating Liner, housing (for bearing of drive shaft and guidance of actuating piston, control piston) engine cylinder (functional surface for engine piston) cylindrical with external coating Engine pistons, actuating pistons, control pistons in the form of cylinder segments, slewing cradle bearing

In particular, the present invention can be used in an axial piston machine and particularly preferably for an engine cylinder and/or a control plate.

The present invention is based on the finding that the loads which lead to component wear, particularly in the case of hydraulic machines and other hydraulic components, occur locally at different strengths on a functional surface FO, so that the proportion by weight of the wear-reducing material M in the functional layer FS or on the function interface FO can be adapted to this.

Physical variables that occur in hydraulic machines and lead to damage and to an increase in losses (e.g. leakage, efficiency, etc.) and are preferably taken into account in the context of the present invention are, for example: friction surface pressure cavitation Acting forces and bending moments as well as deflection and transverse forces

The following loads play a minor role in the context of the present invention: Pressure load, since it is rather critical for seals; Fluid connections that are provided outside of solid components torsional moments temperature

[0175] Examples of the loads that are relevant for different components and considered in the context of the present invention: Translational peripheral speed of drive shaft (if the shaft has different diameters at the different bearing points), engine cylinder & control plate, sliding shoe running surface: locations with increasing distance from the axis of symmetry can be exposed to higher peripheral speeds Surface pressure Engine piston sliding shoe Ball joint connection, plain bearing of the swivel cradle, control plate: Web areas in the vicinity of the control kidneys are subject to higher surface pressure Cavitation Kidney areas (engine cylinder & control plate) Deflection of drive shaft, swivel cradle bearing Lateral forces of engine pistons, actuating pistons

For example, the peripheral speed and thus the stress caused by friction on the contact surfaces of two components BT, BT′, between which a relative rotational movement takes place, increases with increasing distance r from the axis of rotation m. As the distance r from the axis of rotation m increases, the need for dry lubrication increases. According to the present invention, therefore, the lead content Bg in the coating B increases as the distance from the axis of rotation m increases. If the total amount of lead used is limiting, the permitted amount of lead in a component BT is used optimally as a result. If a required operational stability against frictional wear is decisive, the total amount of lead used for this can be significantly reduced.

For this exemplary application, the approach according to the invention provides for the increase in the lead content Bg in the coating B with increasing distance r from the axis of rotation m. The person skilled in the art knows that in a component coating that is necessary for the purpose of better sliding properties, according to the current state of the art and the requirements of hydraulic technology in terms of power density and durability, the wear-reducing material lead cannot be dispensed with.

2 and 3 show two exemplary embodiments for this application, in which a functional layer FS is applied directly (Fig. 2) or by means of a buffer layer PS (Fig. 3) to a base body GK, and in which the lead content Bg in the functional layer FS as a function of the radius r - the distance from the axis of rotation m continuously increases. RB is the outer radius of the component BT.

2 and 3 show a profile of the lead content Bg which, like the relative speed v, increases linearly with the radius r. With this change in the lead content Bg, which in this idealized representation is subject to a continuous increase as a function of the radius r, all areas of the functional layer FS that differ in their radius r each have a different lead content Bg.

In most practical applications, on the other hand, for production reasons, a profile is selected in which there are several radial areas which each have a different lead content Bg from one another, which results in a corresponding number of functional layer areas based on the choice of words already introduced , in each of which, from an idealized perspective, the lead is distributed homogeneously, while the lead content preferably differs in different functional layer areas.

4 to 6 show, as a specific application example of components BT, BT' of an axial piston machine that are supported in rotation on one another, the configuration according to the invention of the functional layer FS in the pairing of an engine cylinder 18 and a control plate 19. The creation or presence of a coating B or A functional layer FS on the entire or in a partial area of the functional surface can be provided on the engine cylinder 18, on the control plate 19 or on both components BT, BT'.

The engine cylinder 18 or the control plate 19, in which the coating B or the functional surface FO covers a functional surface formed by an inner web area 10, a central web area 13 with the control kidneys 12 and an outer web area 11, which serves as a contact surface Function surface FO provides.

In a first embodiment referred to as V1 in FIG. 4, which can be referred to in FIG %, 10%), with the respective lead content Bg remaining approximately the same within a respective web area. This means that there are three coating areas F1, F2 and F3 along the functional surface - which is a partial area of the component surface.

The other starting materials of the functional layer areas F1, F2 and F3 for the individual web areas can be the same or also different or be the same in some functional layer areas and different in other functional layer areas. Furthermore, the weight ratios of the other starting materials in different functional layer areas can be the same or different. For example, the following configuration of the functional layer areas FS1, FS2 and FS3 could be selected: Outer web area 11: functional layer area F3 made of lead-bronze alloy with a lead content Bg of 10%. Middle web area 13: functional layer area F2 made of brass alloy with a lead content Bg of approx. 0.5%. Inner web area 10: functional layer area made of lead-bronze alloy (almost) lead-free.

In variant V1′, with an increasing radial direction, there is an idealized continuous increase, for example a linear increase in the lead content Bg, which extends over the entire functional area.

In a second embodiment, which is also shown in FIG. 4 and is referred to as V2 in FIG. of the relative speed v as an additional load, the surface pressure is taken into account.

There is a lead content Bg increasing in the radial direction from the inner web area 10 to the outer web area 11 (e.g. from 5% to 10%) and a lead content Bg increasing from the middle web area 13 to the outer web area 11 (e.g. from 1% to 10% ) which takes into account the increasing relative speed v. In contrast, the lead content Bg falls from the inner web area 10 to the central web area 13 (e.g. from 5% to 1%). The low lead content Bg in the central web area 13, in which the kidneys 12 are contained, is used to increase the operational strength compared to the surface pressure, which is significantly higher in the peripheral areas over which each kidney extends. It is known that the resistance of a coating B to surface pressure increases with increasing material hardness. So that the functional surface FO, which is designed for its application and created accordingly by the production, is not destroyed or damaged by the prevailing surface pressure, the functional layer area F2 must have a certain minimum material hardness. In relation to this, a harder functional layer FS is necessary or at least advantageous for the central web area 13 .

In variant V2, the lead content Bg within a web area remains the same or approximately the same apart from scattering caused by production. Apart from the radial area over which the kidneys 12 extend in the corresponding circumferential sections, the lead content Bg rises and falls in variant V2' continuously depending on the radius r over the entire remaining area of the functional surface. This means that there is also an idealized continuous change in the lead content Bg in variant V2'.

The functional layer FS in the exemplary embodiment V2' thus also takes into account the fact that the functional surface is loaded with a higher surface pressure in the kidney area. For this reason, the lead content Bg in the inner web area 10 increases strictly monotonously with increasing distance from the axis of rotation m; likewise in the outer bridge area 11. In the kidney area 12 there is an approximately constant lead content Bg, which is lower than that in the other areas. Outside the cardioid area 12, in the remaining portions of the central ridge area 13, the respective lead content Bg approaches the edges of the respectively adjacent ridge area. All in all, this idealized view results in a mathematically constant progression of the lead content Bg.

In the circumferential direction, the lead content Bg remains the same or approximately the same in all the embodiments that have been described up to now.

According to the present invention, the lead content Bg in relation to the thickness direction can range from the top layer of the functional layer FS, which ends with the functional surface FO, to the bottom layer, which ends with the surface of the buffer layer PS or with the surface of the Base body GK concludes, (approximately) be constant. Alternatively, a different lead content Bg can be present in different layers of the functional layer FS. In addition, in a multilayer functional layer FS there can be different layers each with the same lead content Bg and at the same time different layers each with a different lead content Bg. In particular, the invention includes the following configurations I and II (see below).

A cylindrical coordinate system is introduced into the component BT (FIG. 5) for the purpose of explanation. The coordinate origin is on the rotation axis m and the Z coordinate has the value 0 along the drawing plane on which the function surface FO is located. Each position of the functional layer FS is thus defined by the Z coordinate.

In combination I, while maintaining the coordinate values r=r_y and alpha=alpha_y, it applies that in two different layers of the functional layer FS—as far as this is possible under practicable manufacturing conditions—the same lead content Bg is present in a respective layer. This preferably applies without exception to all positions with at least one fixed pair of coordinates r_y0, alpha_y0 or without exception to all pairs of coordinates r_y, alpha_y. With respect to the introduced coordinate system, the lead content is independent of the value of the Z coordinate.

In the combination II there is at least one pair of coordinates r_y, alpha_y, which define certain locations of the functional layer FS, in which there are deliberately brought about - i.e. intended by the production - differences in the lead content Bg in different layers of the functional layer FS; to put it more precisely: there are at least two layers each with a different lead content Bg. For example, the functional layer FS could comprise three layers, and the first layer applied directly to the buffer layer could have a lead content of 1% and the two layers applied above it could have a lead content of 10%. In relation to the coordinate system introduced, the lead content then depends on the value of the Z coordinate.

An embodiment according to the first aspect of the present invention is always present in combination II if in at least two location points of the function layer FS located along the function surface FO or along a parallel line of the function surface FO, i.e. for different r_y, alpha_y the lead content Bg differs from one another in any layer of the functional layer FS. The mean lead content Bg preferably also differs across all layers of the functional layer FS.

The above statements with regard to the lead content Bg of the functional layer FS also apply in the same way to other wear-reducing materials M. In a third variant V3 or V3', increased strength against the surface pressures in the middle web area 13 can be achieved. in that at least one wear-reducing material M′ is added to the functional layer FS applied there, which contributes to increasing the material hardness or the material strength. Wear-reducing materials suitable for this are, for example, molybdenum, bismuth or nickel.

In a simple embodiment, this further wear-reducing material M, e.g. nickel, is contained in a constant proportion by weight in the entire central web area 13 of the functional surface. In a preferred variant, the further wear-reducing material M′ is contained in different weight proportions in the direction of thickness and/or along the functional surface FO or along a parallel of the functional surface FO.

In a preferred variant of a needs-based use of the wear-reducing material M' in the coating of the area near the kidneys, there is an increased weight proportion of the wear-reducing material M' in the remaining area of the central bridge area 13. In a preferred variant, the same features apply to the wear-reducing material M' with regard to its location-dependent proportion by weight as have been explained above for the material example lead.

[0199] In addition, the highest proportion by weight of the wear-reducing material M' is at the kidney ends located in relation to their longitudinal direction, because these areas in the transitional situations - starting from a closed fluid connection via a specific kidney into the opening flow path via this kidney due to the low flow cross-section high flow velocities are present. The same applies to a closing flow path via a specific kidney.

During pump operation, there is an increased risk of cavitation on the suction side in the component areas adjacent to the flow cross section. In order to better protect the areas affected by this or the components BT affected by this from cavitation phenomena, a higher proportion of a correspondingly wear-reducing material M in the coating B there makes sense.

Accordingly, the basic idea of the invention is also based on a starting material, respectively. Wear-reducing material can be used, which can be part of the application material of a functional layer FS or a functional layer area F1 and does not act as a solid lubricant, but to increase the operational stability against other loads, for example, improves the resistance to surface pressure and/or cavitation.

In the third variant V3 or V3′ described above, the lead content Bg in the coating B can vary in the same way as in variant V1 or V1′.

Notes for clarification:

The chemical element molybdenum is a high-strength, tough and hard metal which, when added in small amounts, serves to harden an alloy. On the other hand, molybdenum disulfide is used as a lubricant suspended in lubricating oils or as a solid lubricant.

Bismuth is sometimes cited as a substitute for lead. However, in such a constellation, in which this is technically sensible, the lead or the bismuth does not serve as a solid lubricant, but rather improves the machinability of the alloy and is therefore not related to the present invention. Another constellation in which bismuth can be substituted for lead concerns solar technology.

In the case of the present invention, the use of a certain proportion of bismuth in the functional layer FS would serve to increase the material hardness or to increase the robustness against surface pressures and/or cavitation etc.

The lowest possible use of the three starting materials molybdenum, bismuth and nickel mentioned as representative should be aimed for, because these are comparatively expensive and material separation during recycling is only possible to a limited extent, etc.

In the embodiment shown in FIG. 6, the lead content Bg also varies in the circumferential direction.

As in the previously described embodiment, a lead content Bg increasing in the radial direction from the inner web area 10 to the outer web area 11 is provided (e.g. from 1% to 10%). The central web area 13, on the other hand, is divided into a first partial area 13', which adjoins the control kidneys 12 and, in the exemplary embodiment, surrounds them on all sides. This has a low lead content Bg of, for example, 1%. Since there is increased surface pressure in the vicinity of the kidneys 12, the functional surface FO there or the region of the coating B close to the surface should not be weakened in terms of surface pressure by a comparatively high lead content Bg. In the circumferential direction between these partial areas 13 ′, second partial areas 13 ″ and 13 ″″ are provided, which are arranged further away from the kidneys 12 . A higher lead content Bg of 5% is used here, since the existing surface pressure is correspondingly lower and therefore not decisive for the component.

6 shows two exemplary embodiments. The two exemplary embodiments differ in the extent of the sectors 13" and 13"'. The sector 13″ or 13′″ with the increased lead content Bg extends either only over the middle web area 13 or reaches up to the inner radius ri.

7 shows an exemplary embodiment of a component BT with a running-in layer (ES) which is very thin and has a comparatively high lead content Bg of, for example, 10%. The running-in layer (ES) forms a functional surface F01. After acceptance of the test bench or after the commissioning of the unit in which the component BT is already installed, the running-in layer ES has fulfilled its task and has largely disappeared due to the running-in. The running-in layer ES serves to compensate for component tolerances in the contact area with the other component BT'. A lapping during the production of the component BT can be shortened or even omitted completely. The running-in of the component BT begins, for example, with the commissioning of the customer device in which the component BT is installed.

Possible method steps for achieving a correspondingly optimally thin running-in layer ES are: application of the running-in layer (ES), e.g.

The running-in layer ES is an optional feature which can be used in any other configuration of the present invention.

8 shows an exemplary embodiment of a component BT according to the invention in accordance with the second aspect of the present invention. The functional surface FO or the contact surface to an adjacent component BT′ along the component surface is formed in at least one area by a functional layer FS and in at least one area by a buffer layer PS.

9 again shows a control plate 19 as a specific application, as has already been described above. In the peripheral sections in which there are no openings, the qualitative structure of the coating B of the control plate 19 corresponds to the structure that is shown in FIG. 8 in an abstract form of representation.

As in the previously described exemplary embodiments, a functional layer area F1 with a lower lead content Bg of, for example, 1% is used for the inner web area 10 and a functional layer area F2 with a higher lead content Bg of, for example, 10% is used for the outer web area 11. intended. Both are applied to the base body GK via a buffer layer PS. The middle web area 13, in which the control kidneys 12 are provided, has no functional layer. Rather, the functional surface FO is formed there by the buffer layer PS, which has an increased thickness here and whose surface therefore lies in a common plane with the surfaces of the functional layer regions F1 and F2. In the vicinity of the kidney 12 (here a low-pressure kidney), the functional surface FO is therefore formed by the buffer layer PS.

It is provided that the central web area 13 has a width Bm which is greater than the control kidney width d and extends beyond this on both sides, with the radial overhang of the buffer layer PS, where it forms the functional surface FO, pointing towards the center M is an extension xi and in the diametrical direction thereof the radial projection of the coating B, where it forms the functional surface FO, has the value xa, the dimensions xi, xa being in a range from 0 to 0.3d, preferably in one range from 0.05d to 0.25d and more preferably from 0.1d to 0.2d.

The inner web area 10 with the functional layer area F1 has a width Bi, the outer web area 11 with the functional layer area F2 has a width Ba, and the middle web area 13, in which the functional surface is formed by the buffer layer PS and the Control kidneys 12 extend, have a width Bm. The total width of all three web areas is drawn as B1FS.

In particular, this embodiment relates to a control plate 19 for the use of an axial piston machine in an open circuit. There are low-pressure cardioids a) with R1 = R2 and b) with R1 ≠ R2.

10 shows a perspective view of the two sides of a control plate 19 of an axial piston pump; on the left a view of its functional surface FO, i.e. the side facing engine cylinder 27, thus a view of the functional surface and on the right a view of the surface facing away from engine cylinder 27. The present invention can be applied to this control board 19 shown concretely.

The high-pressure kidneys are denoted by 12' and the low-pressure kidney by 12", the latter also being referred to as a suction kidney in the case of an axial piston pump. A control notch is denoted by 14, which penetrates the coating B and enters the base body GK, without the latter A penetration of the control plate 19 for fixing to the housing 80 is denoted by 15. The groove denoted by 16 is a relief notch which has a relief opening 16' at the end of the groove facing the suction kidney, which penetrates the entire control plate 19.

The invention can also be applied to such control plates 19 of an axial piston machine as shown in FIGS. 11 and 12, which have such a kidney shape and/or arrangement of the kidneys. Again, these are just more examples. Such kidney shapes can be used for both an open and a closed hydraulic circuit.

13 shows an engine cylinder 18 of an axial piston machine. This has a central connection area 17 for connection to the drive shaft 21, which has teeth here. The engine pistons 27 are guided in the engine cylinder 18. An engine piston 27 can be guided directly along the bore wall in the engine cylinder 18 or along the inner wall of a liner 60 inserted in the engine cylinder 18, with the contact surfaces for an engine piston 27 passing through in both cases a coating B can be formed. The coating B (the alloys of the buffer layer and the functional layer areas and the coating process are preferably selected in such a way that only one of the two functional surfaces, i.e. only the contact surface on the engine cylinder 18 or that of the control plate 19, has to be coated. In most cases, there are both base bodies GK are made of a hard material, which usually means that one of the two functional surfaces is provided with a comparatively soft coating B. However, the invention is in no way restricted to this.

In one variant, one or both base bodies GK could be made of a comparatively soft material, preferably a comparatively soft alloy, and the method according to the invention is used, if necessary in addition to other methods, in order to locally reduce the material hardness in the thickness direction is required and/or where a hard functional surface FO is required to produce this by appropriate coating. According to the invention, a (i) buffer layer PS or (ii) a functional layer FS or (iii) a buffer layer PS and a functional layer FS that meets the requirements is applied.

In a further variant, both base bodies GK and GK' could be designed in such a way that good sliding properties result in the contact area and by means of a local coating B of one of the two or both base bodies GK, GK', the components BT, BT' could be ahead of others Stresses such as surface pressure, cavitation, etc. are protected.

Preferably, on the two mutually facing surfaces of two components BT, BT', which touch each other over the entire surface or in a partial area, the surface of one component BT is a hard surface and the polishing made possible by it is a particularly smooth surface, while the surface of the other Component B' is made of a softer material.

In a further variant, with regard to the finished component BT, only certain areas I of the contact area on the control plate 19 could be equipped with a soft functional layer FS, whereas the functional surface FO of the remaining areas II of the contact area (i) of the hard base body GK are formed or (ii) by a hard coating B (a corresponding buffer layer PS and/or a corresponding functional layer FS) or (iii) in a partial area of the hard base body GK and in the remaining partial area of a hard coating B are formed. Those areas II of the contact area could then be equipped with a soft coating B on the functional surface of the control plate 19 .

With reference to FIG. 13, the round-shaped coating B, which has the spectacle-shaped structure due to the kidney-shaped openings, could be applied to the functional surface of the engine cylinder 18, whereas the outer sealing web 16 is different from that shown in FIG Coating B could be applied to the functional surface of the control plate 19.

14 shows an axial piston machine in which the present invention can be used. This has a housing 80 and a connection plate 20 with a drive shaft 21 which is rotatably mounted in the housing 80 and on which the drive mechanism cylinder 18 is arranged. The engine cylinder 18 interacts with the control plate 19, with the overlapping of the respective kidneys 12, the fluid flows - are forced alternately in the piston bores of the engine cylinder 18 in and out again. In the engine cylinder 18 engine pistons 27 are mounted for axial displacement. One end of the engine piston 27 is connected via a ball and socket joint to a sliding shoe 25, which is supported on the swash plate 22, whose inclination to the axis of the engine cylinder 18 can be changed by pivoting about a pivot axis. A swash plate 22 designed in this way is often also referred to as a pivoting cradle. During operation, the engine cylinder 19 rotates with the drive shaft 21. The slide shoes 25 attached to the engine pistons 27 slide along the swash plate 22.

The oblique angle of the swash plate 22 is adjusted by the balance of forces from the actuating force and the restoring force of the spring 28 and a certain reaction force (see below) emanating from the pivoting cradle. The actuating force results from the actuating pressure, which acts on the actuating piston 23 and via the actuating lever 23 on the swash plate 22, respectively. the swivel cradle acts.

[0230] As described in more detail below, the present invention can also be used in other components of an axial piston machine.

However, first possible material hardness profiles in the thickness direction between the functional surface FO and the base body GK are shown with reference to FIG. The material hardness profiles shown on the left refer to applications with a base body GK made of a hard material, in particular steel, on the right a base body GK suitable for lightweight applications, which is preferably made of an aluminum alloy or plastic.

In the constellations shown, the coating B consists of a functional layer FS or of a combination of a buffer layer PS and a functional layer FS. Equally, a coating B according to the invention, as described in the preceding text, can consist locally of only a buffer layer PS. With regard to the qualitative representation of the hardness profiles, however, there is no difference whether a component consists of a base body GK and a functional layer FS or a component consists of a base body GK and a buffer layer PS.

[0233] In lightweight construction applications, the base body GK, which can be made of plastic, for example, often has a low material hardness. A buffer layer PS can be used here, for example, which has a greater material hardness than the base body GK. This also applies if the functional layer FS has a higher material hardness than the base body GK. In such a case, the buffer layer PS, which is harder than the base body GK, can serve to avoid the eggshell effect.

The following hardness values are typical for a component BT according to the invention whose base body GK consists of steel: component body 100 to 500 buffer layer 100 to 200 functional layer 50 to 150

16 now shows, as a further exemplary embodiment, the bearing with the bearing surfaces 34 for the shoulders of a pivoting cradle 30, with the base body GK of the bearing already being incorporated into the pump housing 80 as a blank. A bearing shell 31 is usually located between a support surface 34 for a pivoting cradle 30 and its shoulder. The pivoting cradle 30 carries the swash plate 22 on which the sliding blocks 25 of the engine pistons 27 rotate and supports them against the pump housing 80 . (One-piece components BT, which combine the function of the pivoting cradle 30 and the swash plate 22, are widespread.) To adjust the pivoting cradle 30, it has a lever arm 32 in the exemplary embodiment, on which an actuating cylinder 33 acts.

High working pressures in axial piston machines lead to deflection of the drive shaft 21 and the pivoting cradle 30. As a result, the bearing force coating (see below) of such a component BT loaded by deflection is unevenly distributed on the bearing point in its axial extent. The exemplary embodiment of the bearing point 34 in FIG. 16 takes into account the bearing force covering which changes in the axial direction due to the deflection of the pivoting cradle 30 . Therefore, the coating B of the bearing surface 34 has several (in the exemplary embodiment three) functional layer areas arranged in a row in the axial direction with a lead content Bg that decreases from the inside to the outside, since the inner axial areas are exposed to a much higher force application due to the deflection, while the In the outer areas of a bearing point, the shoulders of the pivoting cradle 30 no longer tend to rest at all.

[0237] Note: The designation force lining is used as the size of force per length.

In the circumferential direction, the areas in this exemplary embodiment each have a constant lead content Bg. However, the areas can also have a changing lead content Bg in the circumferential direction, as is shown below for the bearing shells 31 .

18 and 19 (right) show two exemplary embodiments of different functional layer areas of a bearing shell 31 - i.e. the progression of the lead content Bg of a functional layer FS along the circumferential direction of the functional surface FO - which is used for the roller bearing of a swivel cradle 30 can come. As can be seen in FIG. 19 (left), the lower outer surface on the bearing shell 31 lies on the support for a shoulder of the pivoting cradle 30 in relation to the orientation of the figure, which is often already implemented in the pump housing 80 . The opposite outer surface of the bearing shell 31 corresponds to the functional surface FO, which represents the contact surface for the shoulder of the pivoting cradle 30.

[0240] Both exemplary embodiments have a plurality of functional layer regions F1, F2, F1 lined up in a row in the circumferential direction. The lead content Bg is the same within a functional layer area and different lead contents can be present in different functional layer areas. A functional layer area F with a maximum lead content Bg is present on a central area of its coating B with respect to the circumferential direction of the bearing shell 31 . In relation to the circumferential direction of the central area, one or more areas with a lower lead content Bg adjoin on both sides. In the exemplary embodiment in FIG. 18, the central area is arranged in the center of the bearing shell 31. In the embodiment in Fig. 19 (right), on the other hand, the central area is offset by a certain amount from the center of the bearing shell in order to compensate for the offset of the bearing force FL from the center of the bearing shell in normal operation or in nominal operation by the Zero position to take into account different swivel angles.

20a shows, as an exemplary embodiment, an actuating piston 33 for the hydrostatic adjustment of a pivoting cradle 22, which is accommodated in a component BT that is not specified in any more detail. The actuating piston 33 is guided over a bushing 81 near its right-hand end. Near its left-hand end, the actuating piston 33 is guided directly along the bore wall of the component BT that accommodates it. Depending on the actuating pressure pstell acting on the end face of the actuating piston 33, a torque acting on the pivoting cradle 30 results via the driver 41 acting as a lever arm, which torque determines the oblique angle. On the part of the driver 41 there is a reaction force which is transmitted via the pivoting cradle 30 and which in turn acts as a torque on the actuating piston 33 . Figure 20b shows a gross exaggeration of the effect of said torque. In certain sections, the actuating piston 33 is pressed extremely strongly against its immediately opposite area of its contact surface, whereas in other areas—in this exaggerated but tendentially correct illustration—it is no longer pressed at all against its directly opposite area provided as the contact surface. The resulting transverse forces cause a different force to act on the contact areas 42, which is taken into account by the different lead contents Bg in the circumferential direction along the component surface in the functional layer areas applied to the contact areas 42 and/or in the corresponding sections of the actuating piston. In the exemplary embodiment, functional layer areas F1 and F2 with different lead contents of e.g. 5% and 10% are provided on the contact surfaces.

21 and 22 relate to exemplary embodiments of an embodiment of ball joint connections between an engine piston 27 with a sliding shoe 25 and two exemplary embodiments of the running surfaces 50 of a sliding shoe 25. All of these exemplary embodiments follow the first aspect of the invention. The ball head 26 is arranged here on the sliding shoe 25, but could also be provided on the engine piston 27.

[0243] For the ball-and-socket connection, high operational strength can be achieved by coating application material on the ball head 26 and/or on the contact surface in the spherical cap. Here again it is taken into account that the maximum possible contact pressure between the ball head 26 and the spherical cap does not have the same value over the entire contact surface. For this reason, a subdivision into different areas with a different angle to an axis, here the central axis of the ball head 26, was made, with an area correspondingly provided functional layer area F1 having an approximately constant lead content Bg, whereas in functional layer areas the lead content was different areas correspond to a different lead content Bg may exist. The central areas have a higher lead content Bg and the end areas have a lead-free coating.

The running surface 50 of the sliding shoe 25 and thus the coating B on its underside has a plurality of concentric ring areas, with the lead content Bg being approximately constant within a ring area in this exemplary embodiment, whereas the lead content Bg of the various ring areas increases from the inside to the outside. This ensures that the higher demands on the dry lubrication are met in the outer ring areas, in which the circumferential speeds can be higher when the engine is rotating than in the inside.

On the surface of the sliding shoe 50 facing away from the running surface 50 is the contact surface 51 of the retraction plate, which also has a functional layer FS with a comparatively high lead content Bg.

23a shows the application of the present invention for guiding an engine piston 27 in a bearing bushing 60 introduced in the engine cylinder 18. This is divided in the axial direction into successive sections a, b and c. In one exemplary embodiment, such a section falls in a functional layer area with an approximately constant lead content Bg, whereas different lead contents Bg are provided for different functional layer areas.

By supporting the engine pistons 27 via the sliding blocks 25 on the swash plate 22, the resulting reaction force acts on the engine piston-sliding block unit along the line of action, which corresponds to the axis of symmetry of the sliding block 30.

When the engine piston 27 is fully extended - as shown in Fig. 23 at the top left - due to the long force arm, from the running surface 50 of the sliding shoe 25 to the nearest contact point of the engine piston 27 on the bushing 60 with respect to the selected subdivision in the longitudinal section a the strongest contact pressure of the outer surface of the engine piston 27 on the liner 60, which is why the highest requirements for dry lubrication exist here and therefore the coating B in this section preferably has an increased lead content Bg.

In the longitudinal section b, the maximum load is present with regard to the reaction force applied by the swash plate 22 to the engine piston when the engine piston 27 is retracted into its bushing 60 to the maximum. However, since the force arm from the swash plate 22 to area b of the contact surface is significantly smaller, the maximum lateral force emanating from said reaction force that can act on area b of the liner is significantly smaller than the corresponding maximum lateral force that can act on area a of the liner.

Also in the area of the center position of the engine piston 27 (according to the figure below), the reaction force applied by the swash plate 22 to the engine piston causes a transverse force, since - apart from the case of a not pivoted slanted cradle - there is also an inclined position of the sliding shoe , but is not recognizable in the present orientation of the figure, because here the pivot axis is in the plane of the drawing. As can be seen, there is a force arm between the swash plate 22 and the contact surface of the engine piston 27, which is longer than in the case of the maximum retracted engine piston 27, but the entire contact surface of the liner 60 is available to the engine piston 27 in its middle position.

Even without a final discussion of all the relationships, it becomes clear that the maximum loads occurring during an engine piston working cycle, emanating from said lateral force, for the functional surface of such a liner 60 depending on the length position, respectively. have different heights in different sections of the length. Consequently, the principle according to the invention of a needs-based use of the wear-reducing material M can also be applied to this application example while achieving the advantages.

If the engine piston liners 60 can also be installed in a determinate manner in their circumferential direction, and it is ensured that they remain in this determinate installation orientation even during subsequent operation of the axial piston machine, the principle according to the invention can be extended to the effect that the lead content Bg of a coating B of a liner 60 is not constant over its peripheral area, but needs-based adjustment is possible.

In preparation for explaining this fact, FIG. 23b shows a cross section of an engine piston liner in longitudinal section a. In one exemplary embodiment, a respective peripheral area of the circle drawn with a solid line represents a sector in whose coating B along its surface, according to the invention, a lower lead content Bg is present. In one possible embodiment, these sectors extend over an angular range of 90° each. Likewise, this figure shows the corresponding relationships for length sections b and c. According to the selected nomenclature, the four circumferential sectors would then be labeled B1, B2, B3 and B4 or C1, C2, C3 and C4.

23a, which shows the engine piston 27 in its (almost) maximum position extended out of the piston bore, the so-called top dead center, the resulting transverse force acts in longitudinal section a in relation to the drawing arrangement along the Drawing plane upwards, which is why, considering this transverse force alone, the maximum friction occurs only in this sector A1 (cf. Fig. 23b) of length section a and in sector C3, which is located in the lower area of length section c in relation to the drawing arrangement, there is also an increased load. In sector A1, the load is significantly greater than in sector C3, because between the starting point of the power arm - i.e. the running surface of the sliding shoe 25 - the longitudinal sections a and b are already guided before reaching sector C3.

With the same considerations, one can see from the second partial image of FIG the pressing of the outer surface of the engine piston 27 occur. The same applies in the areas of the perimeter sectors A3, B3 and C3.

In addition to the transverse forces that act on the engine pistons 27 due to the reaction force from the pivot cradle 22, there are other forces (without claiming to be complete): Centrifugal forces directed diametrically to the axis of rotation of the engine Forces of inertia when the engine speed changes rapidly, directed against the direction of acceleration During pump operation, the liner guide surfaces are in contact with the respective engine pistons 27, since the engine pistons 27 are moved in the corresponding direction by the rotational movement of the engine cylinder 19. During engine operation, the liner guide surfaces are in contact with the respective engine pistons 27, since the rotational movement is applied to the engine cylinder starting from the engine pistons 27.

Clearly, the reaction forces, the loads acting via the force arm from the running surface of a slide shoe 25 resting on the swash plate 22 on a specific sector in the bushing, are significantly higher when the engine piston 27 is pressed in the direction of the swash plate by the hydraulic oil under high pressure. than is the case in an operating phase in which the pressing is carried out solely by the retraction device.

Ultimately, the local pressing of the lateral surface of an engine piston 27 to its contact surface in the liner 60 is dependent on the angular position of the engine, respectively, without claiming to be complete. the axial piston position in the engine, the helix angle, the working pressure, the instantaneous absolute speed and its change, the direction of rotation and whether the axial piston machine is working in motor or pump mode, on the oil viscosity and in turn also on the local friction .

In the course of a working cycle, the maximum loads between the lateral surface of an engine piston 27 and its contact surface in the liner 60 are also location-dependent. Furthermore, load location profiles on the said contact surfaces are dependent on the mode of operation of the axial piston machine, not only with regard to the absolute values of the local loads, but also the qualitative course of the load location profiles, e.g. the local load maxima are also shifted along their location points .

[0260] Overall, a prediction of the exact local loads is comparatively difficult, but the load can, for example, be detected by detecting engine pistons 27 that were used in test bench tests, field tests or during regular operation in an axial piston machine.

In this way, the areas of the coating can be identified to a certain degree of accuracy, which in an exemplary embodiment of a liner 60 according to the invention require a three-stage classification of a high, a medium and a low lead content Bg in order on the one hand to meet a required operational strength and yet to enable a far-reaching limitation of the amount of lead used.

As is known, an axial piston machine usually has five or seven engine pistons 27 . Consequently, the benefits of the invention can be exploited multiplicatively to a large extent.

24 to 27 show an in-line piston pump 70 in which the displacement pistons 71 are each mounted in a sliding manner on a cam 72 of the drive shaft 73 .

During the working cycle of a displacement unit, during the suction phase, in which the displacement piston 71 is pressed with its end face against its cam 73 via the return spring 74, there is a comparatively low load on these two contact surfaces. In the compression phase, in which the displacement piston 71 is displaced via the cam contour, as a result of which the pressure of the hydraulic oil is increased to the high-pressure level, there is a correspondingly high contact pressure force. This occurs when the instantaneous distance of the instantaneous contact surface of the cam 73 on the end face of the displacer piston 71 moves further and further away from the axis of rotation of the camshaft 72 . At the latest after a few angular degrees after the top dead center position of the displacement piston 71 has been exceeded, the high pressure has escaped. From then on, the displacement piston 71 is pressed onto the cam 73 via the return spring 74 . This force, which acts as a normal force in relation to the frictional force, is comparatively low, which is why it is possible to reduce the functional layer region F1, which has the highest lead content Bg, without functional disadvantages.

[0265] In addition to the pure upward and downward movement between the bottom and top dead centers of the displacement pistons 71, these also experience a tilting movement. This takes place along an axis of rotation which is aligned parallel to the axis of rotation of the camshaft 73 . The principles according to the invention shown above for an axial piston machine can also be used here. In an idealized, simplified view, only transverse forces that are located on a clearly definable plane E act on a displacement piston 71 . The plane E runs perpendicular to the axis of rotation of the camshaft 73 and along the longitudinal axis of the displacement piston 71. Consequently, the increased requirements for dry lubrication between the outer surface of a displacement piston 71 and its guide surface only exist in two diametrically located circumferential areas. The two centers of these circumferential areas lie on that imaginary plane E. In relation to the orientation including the shown position of the displacer piston 71 and the inscription of Figure 27, with a counterclockwise rotating camshaft 73, the maximum lateral force loads (i) are in the right-hand of the mentioned circumferential areas of length a; and (ii) the left of said circumferential regions of length c.

[0266] If the in-line piston pump 70 is operated predominantly or exclusively in the counter-clockwise direction shown, the last-mentioned area is generally most at risk of wear with regard to the contact surface of the displacement piston. For this reason, increased material strength is required there in particular, which may have to be achieved by providing a buffer layer PS consisting of a hard material. There is also an increased need for dry lubrication there, which is why it can make sense to provide a functional layer FS in this area that has an increased lead content Bg.

In addition, the principle according to the invention can be used for the peripheral area of the cams 72 and/or the end faces of the displacement pistons 71 . With respect to the contact surface of a cam 72 for the end face 74 of a displacer piston 71, a respective requirement-based and thus different weight proportion of lead and/or nickel could be contained in the coating B in the circumferential direction, which would compensate for the different surface pressures, relative speeds and such normal forces that Cause occurrence of friction, take into account. In particular, the areas of the cams 72 that have a strong curvature, i.e. the areas of the contact surfaces that are further away from the axis of rotation, can have a functional layer area F1, F3 that has a higher lead content Bg than a functional layer area F2, F4 that is closer to the axis of rotation of the camshaft 73, see Fig. 26.

If an in-line piston pump 70 is only designed for one direction of rotation, the total area of the two functional layer areas F1, F2 which have the highest lead content Bg, as indicated in the right-hand image of FIG. 26, can be reduced without disadvantages.

If the design is for an in-line piston pump 70, which should be equally suitable for both directions of rotation of the camshaft 72, it is advisable to form pairs of two diametrically located circumferential sectors of a length section whose functional layer FS has the same lead content Bg or can this be attributed to the corresponding areas of the entire coating B are transferred; included the buffer layer PS and the functional layer FS along its surface and/or with respect to its thickness direction.

Within the scope of the present invention, one or more of the following methods for applying the buffer layers and/or functional layers can be used, independently of the specific exemplary embodiment: Deposition welding e.g. laser deposition welding, plasma powder deposition welding etc. Build-up friction welding or friction stir welding Thermal spraying, flame spraying, high-velocity flame spraying, cold gas spraying Coating with the application material on the base body GK by means of 3D printing, in particular laser beam melting & electron beam melting Anti-friction coating for the optional running-in layer (ES)

The application material can, for example, be in the form: a band, in particular a wire of powder

[0272] Furthermore, a preparatory and/or accompanying and/or post-processing conditioning of the resulting component BT can be carried out during the coating with the application material. This can be done, for example, as follows: Before each layer is coated with an application material, the base body GK or the base body GK with the layers already applied is preheated and, after a layer has been applied, a defined temperature profile is applied, i.e. the resulting component BT does not cool according to the natural environmental conditions, but is, for example, initially further exposed to a temperature T or a temperature distribution T* that is higher than the natural environmental temperature, with the temperature T being gradually reduced. In other words, the coating process can be carried out in full or in part by controlled or regulated heat management.

[0273] This can be a heat conduction that spatially extends over the entire component BT that is being produced. The heat can extend over the entire period of time, which includes the coating process, starting from a conditioning of the base body GK to the end of the post-treatment of the fully coated component BT. Alternatively, the heat conduction can extend to a single specific manufacturing step or to a plurality of specific manufacturing steps belonging to the coating process of a component BT, with the heat conduction being able to take place within a single coherent period of time or in separate time windows in each case.

[0274] Local heating, in particular by inductive heating, can be provided. A combination of global and local heating is also conceivable. Influencing parameters in inductive heating are, for example, the operating frequency of the magnetic field, which in turn can result from the operating frequency of the magnetizing current. With increasing frequency, the penetration depth of the triggered eddy currents and thus the penetration depth of the heat source of the workpiece to be heated decreases (keyword: skin effect). In addition, the penetration depth also depends on the material properties and the temperature of the workpiece to be heated. By increasing the peak-to-peak value (peak-to-valley value) of the magnetizing current, the energy input into the workpiece to be heated can be increased.

These methods can be used accordingly for the use of alternative or additional wear-reducing materials M, which advantageously or necessarily should/must be used in the smallest possible amounts, but have a significant positive effect in terms of operational stability.

Two exemplary embodiments of coating methods whose functional layer contains lead are described in more detail below: Preferred method A—initial situation: base body GK made of steel at 0.3 C to 0.5 C—inductive heating to a value between 500° C 600° C., particularly preferably the inner area is heated more than the outer area. During inductive heating, the penetration depth of the eddy current flowing in the component BT can be determined by means of the frequency of the generated magnetic field. - Application of the preferably lead-free buffer layer; multi-layer or single-layer; preferred layer thickness in the range between 0.5 mm and 1 mm; this layer preferably contains the metals nickel and copper. - Level the applied buffer layer PS, e.g. by turning - Apply the functional layer FS resp. the functional layer areas, which differ in their lead content Bg; Functional layer FS preferably consists of a bronze-like application material and preferably has a layer thickness of 1 mm to 2 mm. - Leveling of the applied functional layer FS, e.g. by turning and optionally subsequent lapping - Heating to approx. 300° C to reduce the internal stress in the material - Optional application of a running-in functional layer ES Preferred method B - Initial situation: Basic body GK made of steel with 0.3 C to 0.5 C C - application of the preferably lead-free buffer layer PS; multi-layer or single layer – leveling of the applied buffer layer, e.g. by turning – heating of the raw part (basic body GK with applied buffer layer PS) to approx. 500° C to 600° C for conditioning, so that the functional layer FS to be applied adheres better and due to the adjusted environmental conditions a higher homogeneity has - application of the functional layer FS, respectively. the functional layer areas, which differ in their respective lead content Bg; Functional layer FS consists preferably of a bronze-like material - leveling of the applied functional layer FS, e.g. by turning and optional lapping - heating to approx. 300° C to reduce the internal stress in the material - optional application of a running-in functional layer ES

Production of functional layer areas each with a different lead content Bg and/or different proportions of at least one other wear-reducing material M (see above).

The different lead content Bg in the respective functional layer areas FS can be achieved, for example, by the following variants: A completely pre-mixed application material is used in each case. Preferably, the device via which the application takes place has several independently operable inflows for different compositions of the application material, i.e. (i) application materials whose starting materials are at least partially not the same or (ii) application materials whose starting materials are the same, but at least one of them Starting materials is contained in a different proportion by weight, respectively. In this way, the functional layer areas along the component surface with the different lead contents Bg can be coated one after the other without re-clamping the resulting component BT, i.e. the raw part. The same applies if the functional layer FS is made up of layers with different compositions of the application material. The same applies if the buffer layer PS is built up from different compositions of the application material at different points of a component BT. The lead is added to the application material via a separate inflow. Preferably the lead is in tape form and more preferably in wire form. The lead content Bg can then be brought into the current operating point and/or the current melting point via the feed rate, depending on the location of the functional layer, whereby approximately continuous changes in the lead content Bg along the component surface can be achieved, i.e.: according to the terminology used here, this results in a quasi infinitely many functional layer areas. Introduction of lead into the functional layer FS by means of a method in which the lead is present in the form of small particles, which are accelerated in a targeted manner onto the functional layer FS that is being produced. In the course of this acceleration, the lead particles receive a metered amount of kinetic energy, which causes the lead particles to melt when they hit the resulting functional layer FS, which means that approximately continuous changes in the lead content Bg along the component surface can be achieved.

Coating materials with different lead contents Bg can be achieved, for example, using copper-tin alloys or copper-zinc alloys or corresponding base alloys of this type. Here, lead can be added in varying weight percentages without the need for any other change in the composition of the remaining raw materials of the plating material.

The respective proportions of the other starting materials thus remain constant, regardless of the lead content Bg. This can be, for example, between 1% by weight and 10% by weight. However, it is also possible that with different lead contents Bg of application materials that can be used for the same component BT, the proportions of other starting materials contained therein are also different.

Claims (16)

1. Component (BT), in particular for hydraulic machines and/or components, comprising a base body (GK) and a coating (B) applied to the base body (GK), the coating (B) having a functional layer (FS) in at least one partial area which contains at least one wear-reducing material (M), the wear-reducing material (M) preferably being lead, characterized, that a functional layer area (F1, F2) is provided in at least two areas (A1 to Ai) on the base body (GK), the functional layer (FS) containing the wear-reducing material (M) in the two functional layer areas (F1, F2) in different weight proportions. 2. Component (BT) according to claim 1, wherein part of the functional layer (FS) or the entire functional layer (FS) is applied to the base body (GK) via a buffer layer (PS), the wear-reducing material (M) in the buffer layer (PS) is preferably not included, the buffer layer (PS) preferably having a different and in particular higher material hardness than the functional layer (FS). 3. Component (BT), in particular for hydraulic machines and/or components, comprising a base body (GK) and a coating (B) applied to the base body (GK), the coating (B) having a buffer layer (PS) and a functional layer ( FS), wherein part of the functional layer (FS) or the entire functional layer (FS) is applied to the base body (GK) via the buffer layer (PS), the functional layer (FS) containing at least one wear-reducing material (M), and wherein the wear-reducing material (M) is preferably not contained in the buffer layer (PS) and/or wherein the wear-reducing material (M) is preferably lead, characterized, that a functional surface (FO) of the component is formed in at least a first area (A1) by the buffer layer (PS) and in at least a second area (A2) by a functional layer (FS). 4. Component (BT) according to one of the preceding claims, wherein the at least two areas (A1 to Ai) form a contact area or part of a contact area with another component and/or a contact surface with a fluid, which is preferably a contact area for a rotary movement and/or a translatory movement of the component (BT) relative to a contact area of another component (BT'), with the at least two areas (A1 to Ai) preferably being in relation to an axis of the rotary movement and/or a translatory movement in different radial, axial and / or circumferential areas are arranged. 5. Component (BT) according to claim 4, wherein the at least two areas (A1 to Ai) have a different radial distance to an axis of rotation, wherein the weight proportion of the wear-reducing material (M) of the coating (B) in a first area (A1) with a greater distance from the axis of rotation is higher than in a second area (A2) with a smaller distance from the axis of rotation. 6. Component (BT) according to one of the preceding claims, wherein the component (BT) has at least one fluid passage, the proportion by weight of the wear-reducing material (M) in the coating (B) being in an area (A1) adjoining the fluid passage and preferably at least partially surrounds it, differs from the weight proportion of the wear-reducing material (M) of the coating (B) in at least one area (A2) spaced apart from the fluid passage, the weight proportion of the wear-reducing material (M) of the coating (B) in the region (A1) adjoining the fluid passage is preferably lower than in the region (A2) spaced apart from the fluid passage. 7. Component (BT) according to one of the preceding claims, wherein the coating (B) has a first and a second radial area with a different proportion by weight of the wear-reducing material (M), a third radial area being arranged between the first and the second radial area which has at least one fluid passage and/or the base body GK of the component BT has at least one indentation, at least in a first partial area of the third radial area, which adjoins the fluid passage and/or the indentation and preferably at least partially surrounds the Functional surface (FO) is formed by a buffer layer (PS) or a functional layer (FS), with the buffer layer (PS) or functional layer (FS) preferably having a different weight proportion of the wear-reducing material (M) in this sub-area of the third radial area than in at least one spaced from the fluid passage nded second partial area of the third radial area and/or than in the first and/or second radial area. 8. Component (BT) according to one of the preceding claims, which has a contact area with another component (BT'), a relative rotational movement and/or a relative translatory movement taking place between the two components (BT) and (BT'), the contact area preferably comprising at least two areas (A1 to Ai) arranged next to one another in the axial and/or circumferential direction, in which the coating (B) has a different proportion by weight of the wear-reducing material (M) and/or the coating (B) is a component of at least a ball head connection bearing surface and preferably comprises at least two regions (A1 to Ai) arranged radially next to one another with respect to an axis, in which the coating (B) has different weight proportions of the wear-reducing material (M). 9. Component (BT) according to one of the preceding claims, wherein the component (BT) has at least three areas (A1, A2 to Ai) in which the coating (B) has different weight proportions of the wear-reducing material (M) and/or wherein the at least two or at least three areas (A1), (A2) to (Ai) directly adjoin one another and/or form a common functional surface (FO) or together form a sub-area of a functional surface of a component (BT). 10. Component (BT) according to one of the preceding claims, wherein an additional running-in layer (ES) is applied at least to a partial area of the surface of the coating (B), the running-in layer (ES) preferably the functional layer (FS) in the at least two areas (A1, to Ai) covered and / or wherein the thickness of the running-in layer (ES) is preferably less than the thickness of the functional layer (FS) and / or in the range from 0.05 to 0.2 millimeters, preferably from 0.05 to 0.1 millimeter and more preferably from 0.05 to 0.075 millimeter and/or wherein the running-in layer (ES) preferably has a higher proportion by weight of the wear-reducing material (M) than the functional layer (FS) in each of its at least two areas (A1 to Ai). 11. Component (BT) according to one of the preceding claims, wherein the proportion by weight of the wear-reducing material (M) in the at least two areas (A1 to Ai) in the functional layer (FS) is between 0.1% and 30%, preferably between 0.1% and 20%, and particularly preferably between 0.1% and 10% and/or the proportion by weight of the wear-reducing material in the at least two areas (A1 to Ai) in the coating (B) being at least 0.5 % differs, preferably by at least 2%. 12. Component (BT) according to one of the preceding claims, wherein one, several or all of the functional layer areas (F1 to Fi) and/or buffer layer areas comprise at least one layer which consists of one of the following alloys, preferably all layers of the functional layer area(s) (F1 to Fi) and/or buffer layer areas consist of one of the following alloys: - A copper-zinc alloy and/or copper-zinc base alloy with optionally further alloy components, the copper content preferably being between 50 wt% and 70 wt%, more preferably between 55 wt% and 65 wt% and/or the zinc content being between 25% by weight to 45% by weight, preferably between 30% by weight and 40% by weight, - a copper-tin alloy and/or a copper-tin base alloy with optionally further alloy components, the weight ratio between copper and tin preferably being in a range from 5 to 15 and particularly preferably in a range from 6 to 12, wherein the alloy preferably also contains nickel - A chromium-nickel alloy and / or chromium-nickel base alloy with other alloying components, where appropriate, the chromium content preferably between 15 wt% and 30 wt%, more preferably between 18 wt% and 25 wt% and / or the nickel content between 50% by weight and 70% by weight, preferably between 53% by weight and 63% by weight. 13. Component (BT) according to one of the preceding claims, which is a component (BT) of an axial piston machine, in particular a cylinder drum, a control plate, an engine piston, a bushing, a sliding shoe, a swash plate, a bearing shell, a swivel cradle , a drive shaft, an actuating piston or another component (BT '), which has the support or the guide surface of a corresponding component (BT). 14. Component (BT) according to one of claims 1 to 12, which is a component (BT) of a gear unit, in particular an internal rotor, an external rotor and/or a contact surface, in particular a housing contact surface for the assembly or a component ( BT) of a radial or in-line piston machine, in particular an engine or displacement piston, a bushing or another component (BT') which has the bearing or the guide surface of a corresponding component (BT) or a component which has a contact surface of a ball joint connection having a hydraulic machine. 15. Hydraulic machine and / or component with a component (BT) according to any one of the preceding claims. 16. The method for producing a component (BT) according to any one of claims 1 to 14, wherein a functional layer (FS ) is applied, the proportion by weight of the wear-reducing material (M) being different in at least two of the existing areas (A1 to Ai).