The invention relates to a brake calliper for a vehicle brake system of the type specified in independent patent claim 1 and to a method for producing a casting of the type specified in independent patent claim 5, and to a device for producing a casting of the type specified in independent patent claim 8.
Known brake callipers for vehicle brake systems are generally produced as castings with rough guide structures for the brake pistons. These rough guide structures are then finished by means of appropriate machining or production processes in order to obtain a desired production quality for the guide structures. Since shrinkage cavities which form in the casting during the casting process have a negative effect on the introduction of the guide structures with the defined production quality, the reject rate can be considerable.
In contrast, the brake calliper according to the invention for a vehicle brake system having the features of independent patent claim 1 has the advantage that the at least one guide structure in the housing produced as a casting is formed by at least one prefabricated insert with a defined production quality, which is encapsulated by the cast material of the housing. By means of the prefabricated insert, it is advantageously possible to embody the guide structure with a defined production quality independently of the casting process.
A method for producing a casting with at least one guide structure having the features of independent patent claim 6 has the advantage that the at least one guide structure with a defined production quality is introduced into the casting by means of at least one prefabricated insert, wherein the at least one insert is positioned in the casting tool using at least one positioning means. During the casting process, the remaining cavities within the casting tool are filled with a melt. After the casting process, the casting tool and the positioning means are removed, and the casting with the at least one guide structure with the defined production quality can be removed.
A device for producing a casting with at least one guide structure having the features of independent patent claim 8 has the advantage that at least one prefabricated insert for introducing the at least one guide structure with a defined production quality into the casting is positioned in the casting tool using at least one positioning means, wherein the remaining cavities within the casting tool can be filled with a melt during the casting process, and wherein, after the casting process, the at least one casting mold and the positioning means can be removed, and the casting with the at least one guide structure with the defined production quality can be removed.
The method according to the invention and the device according to the invention are preferably used to produce a brake calliper according to the invention.
By using prefabricated inserts, the desired production quality of the guide structure can advantageously be implemented in a simple and economical manner before the casting operation, without expensive and difficult finish machining of a rough structure. Moreover, embodiments of the invention advantageously allow an improvement in efficiency in the production of castings which have at least one guide structure with a defined production quality since the reject rate can be significantly reduced because shrinkage cavities in the casting which occur during the casting process cannot have a negative effect on the introduction of the at least one guide structure with the defined production quality. Moreover, the guide surfaces in the insert can be produced with greater smoothness and uniformity by virtue of prefabrication. Moreover, grooves for accommodating seals and fixing and/or protective collars can be introduced more easily and more quickly into the casting by means of the insert than is possible with difficult machining or production processes carried out after the casting process and involving complex tool shapes, such as angular milling heads.
Advantageous improvements of the brake calliper for a vehicle brake system, as specified in independent patent claim 1, of the method for producing a casting with at least one guide structure, as specified in independent patent claim 5, and of the device for producing a casting with at least one guide structure, as specified in independent patent claim 8, are possible by means of the measures and developments presented in the dependent claims.
It is particularly advantageous that the at least one prefabricated insert is embodied as a cylindrical bush and/or as a deep-drawn sleeve. The embodiment of the insert as a cylindrical bush is a particularly simple way of implementing the guide structure with the defined production quality. Moreover, the use of an open cylindrical bush instead of a blind hole makes it possible to simplify the handling and subsequent additional installation of components, such as the brake piston, piston seals etc., without direct access. Moreover, a groove for guiding or accommodating seals and/or fixing and/or protective collars can be arranged in a simple manner on the outside diameter of the cylindrical bush. For better positioning and/or fixing in the casting, the cylindrical bushes have raised portions and depressions in the form of grooves, slots etc. on the outer contours thereof. To produce the deep-drawn sleeve, the bottom of the sleeve is deep-drawn from a sheet-metal plate, and the sleeve stem is then punched out. The remaining sheet metal is folded twice, for example, and can be used as a projecting collar to guide or accommodate seals and/or fixing and/or protective collars. In addition, a brake line can be secured on the bottom of the insert prefabricated as a deep-drawn part, said brake line being connected to the cavity of the deep-drawn part. This advantageously makes it possible to eliminate the hydraulic sealing requirements on the cast housing since the brake fluid no longer comes into contact with the cast housing.
As a development of the brake calliper according to the invention, at least two guide structures are provided in the housing, being arranged coaxially with one another at a defined spacing in opposite housing parts of the housing. The guide structures are arranged opposite one another in pairs in order to achieve uniform loading of the brake disk during the braking operation.
As a development of the method according to the invention, the guide structure of the at least one prefabricated insert is produced with a final quality and is arranged with at least one casting core to form a composite in such a way that all the guide surfaces of the at least one insert which are produced with the final quality are covered by the at least one casting core. As a result, the guide surfaces produced with the final quality are advantageously protected from the melt during the casting process.
As a further development of the method according to the invention, the at least one casting core is positioned and fixed on a core support shaft connected to the casting tool, wherein, to produce a casting with two guide structures arranged coaxially opposite one another, a first composite, consisting of a first prefabricated insert and a first casting core, and a second composite, consisting of a second prefabricated insert and a second casting core, are positioned and fixed on the core support shaft. This advantageously allows simple and rapid positioning of the prefabricated inserts, making possible very precise coaxial arrangement of the oppositely situated guide structures in order to achieve uniform loading of the brake disk during the braking operation in use of the brakes as intended.
As a development of the device according to the invention, the at least one prefabricated insert is produced with a final quality and forms a composite with at least one casting core, which covers all the guide surfaces of the insert in order advantageously to protect the guide surface produced with the final quality from the melt during the casting process. The at least one casting core is, for example, positioned and fixed on a guide shaft, which is fixed at both ends in a first casting mold of the casting tool. By means of the fixing at both ends, it is advantageously possible to prevent a shift in position during the casting process. To produce a casting with two guide structures arranged coaxially opposite one another, a first composite, consisting of a first prefabricated insert and a first casting core, and a second composite, consisting of a second prefabricated insert and a second casting core, are positioned and fixed on the core support shaft. In this case, the core support shaft has at least two different outside diameters, which correspond to different inside diameters of the casting cores, wherein, first of all, the first casting core having the larger inside diameter is pushed onto the core support shaft and fixed axially on the core support shaft with first fixing means, and the second casting core having the smaller inside diameter is pushed onto the core support shaft until it abuts an offset at the transition between the different outside diameters, and is fixed on the core support shaft with second fixing means. The use of different diameters facilitates the axial positioning and fixing of the casting cores by virtue of the offsets which are formed.
Advantageous embodiments of the invention are illustrated in the drawings and are described below.
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To produce the cast housing 10, the remaining cavities within the casting tool 1 are filled with a melt during the casting process, wherein, after the casting process, the casting mold 3, the outer contour casting core 9, the two casting cores 22, 24 and the core support shaft 5 are removed, allowing the casting 10 with the two guide structures 11 with a defined production quality to be removed.
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In embodiments of the invention, the desired production quality of the guide structure in a casting can advantageously be implemented in a simple and economical manner before the casting operation, without expensive and difficult finish machining of a rough structure. Moreover, embodiments of the invention advantageously allow an improvement in efficiency in the production of castings which have at least one guide structure with a defined production quality since the reject rate can be significantly reduced.
Number | Date | Country | Kind |
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10 2009 055 420.3 | Dec 2009 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2010/066891 | 11/5/2010 | WO | 00 | 1/7/2013 |