CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of German Patent Application Serial No. DE 10 2018 213 766.8 filed on Aug. 16, 2018, pursuant to 35 U.S.C. 119(a)-(d), the content of which is incorporated herein by reference in its entirety as if fully set forth herein.

FIELD OF THE INVENTION

The invention relates to a housing component for the production of a housing of a multi-shaft screw machine and to a multi-shaft screw machine comprising at least one housing component of that kind. The invention further relates to a method for the production of a housing component.

BACKGROUND OF THE INVENTION

From U.S. Pat. No. 5,816,699 A, a housing section for a multi-shaft screw machine is known. The housing section comprises an insert, in which two bores are configured, which are interpenetrating each other. The bores, on their entire surface, are limited by a wear and corrosion resistant layer, which is configured on the insert, for example, by hot isotactic pressing or by plasma arc welding.

SUMMARY OF THE INVENTION

An object of the present invention is to create a housing component for the production of a housing of a multi-shaft screw machine, which ensures a simple and reliable wear protection. The housing component, in particular, shall have a positive influence on the material processing in the multi-shaft screw machine, as well.

This object is achieved by a housing component for the production of a housing of a multi-shaft screw machine comprising a base body, at least two bores, which are configured in the base body and are interpenetrating each other, which extend in a conveying direction through the base body, and which are limited transversely to the conveying direction by an inner wall of the base body. Due to the at least one second wall section, which is softer in comparison to the at least one first wall section, the risk of cracks and the growth of cracks in the at least one first wall section is reduced and limited, with the result that damages to the inner wall by crack formation and/or spalling are reduced and in particular avoided.

The at least one first wall section and the at least one second wall section, preferably, are configured such that—from a sectional view—a profiled configuration of the inner wall is allowed for, having a positive influence on the material processing in the multi-shaft screw machine. The inner wall is roughened locally in a targeted manner due to the profile. The at least one first wall section thus has a first radial distance to a central longitudinal axis of the respective bore, whereas the at least one second wall section has a second radial distance to the central longitudinal axis of the respective bore. The first radial distance differs from the second radial distance, with the result that the inner wall is configured in a profiled manner A profile of the inner wall, in particular, can be produced such that the at least one first wall section or the at least one second wall section is configured by application of a material layer, or such that the at least one first wall section and the at least one second wall section are configured by application of material layers of different layer thickness, or such that the at least one first wall section or the at least one second wall section is configured by material removal. The material removal takes place during the production of the housing component, for example mechanically by screwing in grooves, and/or during the operation of the multi-shaft screw machine. If the at least one second wall section is configured such that during the operation of the multi-shaft screw machine, a targeted material removal takes place in the at least one second wall section, the profile of the inner wall is created during the operation of the multi-shaft screw machine. Due to a profiled inner wall, in particular, the fusion behavior and/or the flow rate of the multi-shaft screw machine are influenced in a positive manner.

The at least one first wall section and the at least one second wall section are configured side by side and thus form the inner wall. The at least one first wall section and the at least one second wall section thus are in contact with the material to be processed during the operation of the multi-shaft screw machine. Preferably, the inner wall is configured by a plurality of first wall sections and at least one second wall section or by at least one first wall section and a plurality of second wall sections. A respective wall section, in particular, is configured in a coherent manner. Respectively different wall sections, in particular, are configured separately. Preferably, the inner wall configures a plurality of first wall sections and a plurality of second wall sections.

The at least one first wall section, in particular, in configured in a wear-protected manner. For example, the at least one first wall section is hardened and/or made of a hard material. The at least one second wall section, in particular, is configured in a non-wear-protected manner and, in particular, not treated in order to increase its material hardness. The at least one second wall section, for example, is configured by the basic material or the basic raw material of the housing component. The basic raw material is known and common. As basic raw material, for example, the raw material 1.4112 can be used.

The at least one first wall section and the at least one second wall section configure an inner surface of the inner wall. The at least one first wall section and/or the at least one second wall section can be configured due to the treatment of a basic material of the base body and/or due to an application of a material layer onto a basic material of the base body. A treatment, in particular, comprises a hardening, such as for example surface hardening, diffusion hardening (nitriding, nitrocarburizing), electron beam hardening, laser hardening and/or inductive hardening. The hardening takes place, in particular, by thermal processes. The at least one first wall section and/or the at least one second wall section can be configured on at least one basic layer of the base body. The at least one basic layer can be softer than the at least one first wall section and—if applicable—can also be softer than the at least one second wall section. Further on, the at least one basic layer can be harder than the at least one second wall section and—if applicable—can also be harder than the at least one first wall section.

The hardness of the wall sections is determined, for example, according to Brinell (HB) subject to DIN EN ISO 6506-1 or according to Vickers (HV) subject to DIN EN ISO 6507-1 or according to Rockwell (HRC) subject to DIN EN ISO 6508.

The housing component can be configured as a housing section. Further on, the housing component can be configured as a bushing, which is inserted into a housing base body, with the result that a housing section is configured.

A housing component wherein the inner wall configures a plurality of first wall sections and a plurality of second wall sections, which are arranged alternatingly to one another, ensures a reliable wear protection and a positive influence on the material processing. Due to the alternating arrangement of first wall sections and second wall sections, from a qualitative point of view, wall section sequences in the hardness degree hard/soft/hard, in particular hart/soft/hard/soft/hard or soft/hard/soft, in particular soft/hard/soft/hard/soft can be created. The hardness degree between respectively adjacent wall sections thus alternatingly decreases and increases or increases and decreases. The comparably softer second wall sections absorb tensions of the harder first wall sections and avoid crack growth and spalling. In addition, the second wall sections allow for a profile of the inner wall in a flexible manner.

Preferably, the at least one second wall section has a smaller surface than the at least one first wall section. The proportion of the at least one second wall section in the inner surface thus is lower than the proportion of the at least one first wall section. The first wall sections, to some degree, protect the intermediate, softer second wall section. After a certain material removal of the second wall sections, in addition, a material to be processed in the multi-shaft screw machine can accumulate, which provides for a wear protection and/or a lubricating function, depending on the material. Such a material, for example, comprises ceramic particles or metallic particles. Additionally, after a material removal, a plastic molten film can develop, forming a kind of lubricating film and avoiding further wear of the second wall sections and/or providing for a lubricating function. Thus, due to the removed material, a lubricant reservoir is configured. A profile of the inner wall, for example, leads to an increase in shear forces in the fusing region.

A housing component, wherein the at least one first wall section and/or the at least one second wall section is arranged in at least one triangle region of the inner wall (W), ensures a reliable wear protection and a positive influence on the material processing. By respectively two bores interpenetrating each other, triangle regions opposing each other are configured. In the triangle regions, material stress and thus wear and tear is high. Due to the arrangement of the wall sections in at least one of the triangle regions, the wear protection is optimized and, in particular, a positive influence on the material processing is provided for. The triangle regions are arranged centrally between central longitudinal axes of the bores interpenetrating each other. The triangle regions, in particular, have a dimension transverse or perpendicular to the conveying direction, which by definition corresponds to 20%, in particular to 30%, in particular to 40%, in particular to 60%, in particular to 80%, and in particular to 100% of the axis-center distance of the central longitudinal axes of the adjacent bores.

A housing component, wherein the at least one first wall section and/or the at least one second wall section is arranged in at least one side region of the inner wall, ensures a reliable wear protection and a positive influence on the material processing. The central longitudinal axes of respectively two bores interpenetrating each other define a respective central longitudinal plane. The side regions are arranged centrally to the respective central longitudinal plane. The side regions are arranged opposite to a penetration opening of the bores interpenetrating each other. The side regions have a dimension perpendicular to the respective central longitudinal plane, which by definition corresponds to 30%, in particular to 40%, and in particular to 50% of a diameter of the bores. In particular in the fusing region or plasticizing region, the treatment element shafts tend to inclination, which brings them into contact with the inner wall of the respective housing component in the side regions. The treatment element shafts thus run towards the housing component. Due to the metal-metal contact of the treatment element shafts and the housing component, the housing component is stressed to a large extent, which leads to an adhesive wear. Due to the configuration of the inner wall in the side regions, a wear protection is ensured.

A housing component, wherein the at least one first wall section and/or the at least one second wall section is configured in a strip-shaped manner, ensures a reliable wear protection and a positive influence on the material processing. Strip-shaped in particular means that for a longitudinal extension x in relation to a transverse extension y, it is provided that: x/y≥2, in particular x/y≥4, and in particular x/y≥10. Preferably, the at least one wall section extends in the conveying direction and/or extends perpendicularly to the conveying direction. The at least one wall section, for example, extends exclusively in conveying direction or exclusively perpendicularly to the conveying direction or spirally in the conveying direction or transversely to the conveying direction. The first wall sections and/or the second wall sections, in particular, are arranged in rows, which run in the conveying direction, transversely to the conveying direction or perpendicularly to the conveying direction. Further on, the first wall sections and/or the second wall sections, for example, are arranged spirally with identical and/or different offset angles.

A housing component, wherein the at least one first wall section and/or the at least one second wall section runs in the direction of the conveying direction, ensures a reliable wear protection and a positive influence on the material processing. Preferably, the respective at least one wall section, with a main extension direction, exclusively runs in the conveying direction. The respective at least one wall section, preferably, extends over the entire length of the at least two bores. Preferably, the respective at least one wall section is configured in a strip-shaped manner, with the result that a dimension x in longitudinal direction corresponds to a length of the at least two bores.

A housing component, wherein the at least one first wall section and/or the at least one second wall section runs around at least one central longitudinal axis of the at least two bores, ensures a reliable wear protection and a positive influence on the material processing. The at least one wall section, with a main extension direction, at least section-wise, runs around at least one of the central longitudinal axes. The at least one wall section, for example, runs spirally in the conveying direction or against the conveying direction. The spiral course, for example, extends along one of the bores and is interrupted by a penetration opening of the at least two bores. The spiral course or the grade of the spiral course, for example, is adapted to the grade of the treatment element shafts or the screw elements of the treatment element shafts. A negative grade of the spiral course, with regard to the grade of the screw elements, increases the shear rates, whereas a positive grade decreases the shear rates. Due to reduced shear rates, the material stress of the material to be processed is reduced, as well. Further on, the spiral course, for example, extends along all bores, with the result that the spiral course is not interrupted. Moreover, the respective at least one wall section, for example, exclusively runs perpendicularly to the conveying direction.

A housing component, wherein the at least one first wall section and/or the at least one second wall section is configured as a material layer applied onto the base body, ensures a reliable wear protection and a positive influence on the material processing. The application of the material layer, in particular, takes place by at least one of the following application types: laser welding, PTA welding (PTA: Plasma Transferred Arc), electrode welding, thermal injection, hot isotactic pressing, sintering, soldering, additive production, Chemical Vapor Deposition coating and/or Physical Vapor Deposition coating, case hardening, coating by detonation, nitriding, boriding. For a radial layer thickness D of the material layer, preferably, it is provided that: 0.1 mm≤D≤30 mm, in particular 1.0 mm≤D≤25 mm, in particular 2.0 mm≤D≤20 mm, in particular 4.0 mm≤D≤15 mm, in particular 6.0 mm≤D≤10 mm.

For the configuration of the at least one first wall section, a material layer is applied, comprising at least one material chosen from the following materials:

Cobalt base alloys (stellites), NiCrBSi base alloys, powder metallurgical tool steels with or without hard material portion and with iron basis, composite materials of at least one of the aforementioned raw materials with additional carbide and/or nitride hard material intercalations, CrN, TiAlN, TiC.

For the configuration of the at least one second wall section, a material layer is applied, comprising at least one material chosen from the following materials:

High-grade steels, low-alloy steels, nickel-based raw materials, NiCr70Nb, aluminum, brass, bronzes, such as for example Al bronzes, Cu bronzes or Ni bronzes, Waukesha alloys.

The respective material layer, in particular, is applied onto at least one basic layer, which is configured on the base body. The at least one basic layer, in particular, is harder than the at least one second wall section. The at least one basic layer, for example, is softer or harder than the at least one first wall section. Further on, the respective material layer, for example, is applied onto at least one basic layer, which is softer than the at least one first wall section. The at least one basic layer, for example, is harder or softer than the at least one second wall section. The respective hardness degree of the at least one basic layer can be chosen randomly, according to the requirements, in relation to the hardness degree of the at least one first wall section and/or the at least one second wall section.

Another object of the invention is to create a multi-shaft screw machine, which ensures a simple and reliable wear protection. The multi-shaft screw machine, in particular by the configuration of the housing, shall have a positive influence on the material processing.

This object is achieved by a multi-shaft screw machine comprising a housing, which comprises at least one housing component, at least two housing bores configured in the housing and interpenetrating each other, and at least two treatment element shafts arranged in a pivotable manner in the housing bores. The advantages of the multi-shaft screw machine according to the invention correspond to the advantages already described with regard to the housing component according to the invention. Preferably, the multi-shaft screw machine is configured as a two-shaft screw machine, which comprises two interpenetrating housing bores and two treatment element shafts arranged in the housing bores. The multi-shaft screw machine, preferably, is pivotable or pivoted in the same direction. The at least two treatment element shafts are thus pivotable or pivoted in the same directions of rotation. The at least two treatment element shafts, in particular, are configured closely intermeshing. The at least two treatment element shafts, preferably, strip off the housing inner wall of housing, in particular entirely. The housing component, for example, is configured as a housing section and/or as a bushing for the connection with a housing base body in order to configure a housing section.

A multi-shaft screw machine, wherein the housing comprises at least two housing components, which are configured identically, ensures a reliable wear protection and a positive influence on the material processing. The at least two identical housing components, in particular, are arranged one directly after the other in the conveying direction. Due to this, the configuration of a functional area is possible, whose length in the conveying direction is larger than the length of a housing component in the conveying direction. For example, the configuration of a plasticizing area or fusing area is possible, which extends over a plurality of housing components. The housing components, in particular, allow for an improved material processing and/or a relief or a lower wear and tear in the plasticizing area or fusing area and the homogenization area. Due to this, the process component can be configured in a comparatively shorter manner, since the material can be fused quicker and homogenized or processed better.

A multi-shaft screw machine, wherein the housing comprises at least two housing components, which are configured differently, ensures a reliable wear protection and a positive influence on the material processing. The different housing components allow for the configuration of different functional areas. In the respective functional area, the respective corresponding housing component supports the designated function. The designated function, for example, is predefined by the configuration of the treatment element shafts. The multi-shaft screw machine, for example, has at least two of the following functional areas: feed area, fusion area or plasticizing area, degassing area, homogenization area, mixing area, pressurization area. In the respective functional area, the at least one housing component is configured such that the designated function is supported and/or a desired wear protection is achieved. In particular, due to a profile of the inner wall and a volume expansion resulting therefrom, the material processing is positively influenced.

Yet another object of the invention is to create a method for the production of a housing component for a multi-shaft screw machine, which ensures a simple and reliable wear protection. Due to the production of the housing component, in particular, the material processing in the multi-shaft screw machine shall be positively influenced.

This object is achieved by a method for the production of a housing component, including the steps: providing a base body, in which at least two bores interpenetrating each other are configured, wherein the bores extend in a conveying direction through the base body, and the bores are limited transversely to the conveying direction by an inner wall of the base body, and configuring at least one first wall section and at least one second wall section of the inner wall such that the at least one first wall section is harder than the at least one second wall section. The advantages of the method according to the invention correspond to the advantages already described with regard to the housing component according to the invention or the multi-shaft screw machine produced therewith. The method according to the invention may in particular also be extended with the features of the inventive housing component. Preferably, the method according to the invention is part of a method for the production of a multi-shaft screw machine. The method for the production of the multi-shaft screw machine, in particular, comprises the production of a housing, which comprises at least one housing component according to the invention. The method for the production of the multi-shaft screw machine may in particular also be extended with the features of the inventive multi-shaft screw machine.

Further features, advantages and details of the invention arise from the following description of several exemplary embodiments.

