EP2114590B1 - Method for the production of a cylinder crank housing having multiple cylinder sleeves and short cylinder sleeves with material strips fixed thereto - Google Patents

Abstract

A strip (3) is fixed to the crankcase-end of the liner (1). The liner is located in a casting mold, where the metal forming the block is cast around it. The strip (3) projects axially from the end of the liner. Strip attachment facilitates location of the liner in the casting mold. Liner length is essentially that of the piston stroke. Combined length of liner and strip, is essentially that of the respective cylinder bore. After casting around the liner, the strip is removed. Pairs of liners contact each other, at least partially, when located for casting, but the strips do not. Further details of the strip projection and its means of fastening and location are disclosed. The liner is made from light metal or a light alloy, as is the strip. The liner is formed from spray-compacted material. The strip metal differs from that of the liner, and is thinner, at only half the thickness. Its axial extent is less than that of the liner. To make the liner, a bar produced by spray-compaction of a light metal or light alloy, is extruded to a cylindrical tube, to form the body (2) of the liner. The liner is machined internally to surface it, before adding the strip. The strip is fixed by pressing-in or adhesion. After fixing, it has a cylindrical form coaxial with the liner. It includes a seam parallel with the liner axis. An independent claim IS INCLUDED FOR the corresponding liner with strip.

Description

The invention relates to a method according to the preamble of claim 1 for the production of a cylinder crankcase with a plurality of cylinder liners. The invention further relates to a cylinder liner according to the preamble of claim 5 with a material strip fixed thereto.

For the production of cylinder crankcases of internal combustion engines, it is a common method to pour cylinder liners in the cylinder crankcase, which consist of a particularly resistant material and have suitable tribological properties. These cylinder liners usually extend over the entire length of the cylinder bore.

DE 101 53 720 C2 shows a cylinder crankcase with short cylinder liners, which extend substantially between the top and bottom dead center of the piston movement, and a method for producing such a cylinder crankcase. For the manufacture of the cylinder crankcase, a casting mold with sleeves is used, wherein the short cylinder liners are placed on the sleeves before the casting of the cylinder crankcase and are held by a projection firmly connected to the sleeve. The positioning of the quill and the cylinder liner within the mold is effected by slides. The cylinder liners themselves differ by a shortened axial extent of the usual cylinder liners. A disadvantage of this method is that the placed on the quill and held by a projection of the sleeve cylinder liner can tilt during the guided by the slide movement. Since the cylinder liner is a rigid body, it may damage the mold. Of Further, the cylinder liner does not completely cover the quill, resulting in contact between the hot casting material and the quill during the casting process. This leads to increased wear of the quill.

DE 102 38 873 B4 shows a cylinder liner for a cylinder crankcase, which has a contouring on its crankshaft side end face. During the casting process for producing a cylinder crankcase, the cylinder liner is held on a quill and is supported by the contoured end face on the quill. The closed, non-contoured portion of the surface of the cylinder liner extends between the cylinder head end of the cylinder liner and the bottom dead center of the lowermost piston ring during piston movement. The positioned on a Quill cylinder liner is supported on its contoured face only at the highest elevations of the contour of the quill. This complicates a correct alignment of the cylinder liner axis parallel to the direction of rotation of the cylinder and favors tilting of the cylinder liner. At the conditionally not covered by the contour of the cylinder liner surfaces, the sleeve is also unprotected against contact with the Umgußmaterial.

JP 06 185 401 A shows a cylinder crankcase with a short liner. The axial extent of the bushing is dimensioned so that it extends only over the length of the piston rings when the piston is in the top dead center of its movement.

DE 101 53 721 B4 shows a casting tool for producing a cylinder crankcase, wherein a cylinder liner is poured into the cylinder crankcase. The cylinder liner does not extend the full length of the cylinder bore but is spaced at its cylinder head end by a spacer ring to an upper wall of the mold during the manufacturing process. In the cylinder crankcase so produced, the cylinder liner is at her Cylinder head side end of the casting material clasped and held. The disadvantage here is that the positioning of the spacer must be done with great precision to comply with predetermined tolerances, and that the spacer must be removed in a subsequent operation again.

EP 0 871 791 B1 describes a method for the production of thin-walled tubes from a spray-compacted AlSi alloy, which is particularly suitable for the production of cylinder liners, since the manufactured tubes have the required cylinder liners properties in terms of wear resistance, high temperature resistance and reduction of pollutant emissions.

EP 0 858 517 B1 describes a method of manufacturing casings from a hypereutectic AlSi alloy by spray compacting.

EP 0 848 760 B1 describes another method for making cylinder liners from a spray-compacted hypereutectic AlSi alloy.

DE 102 25 657 B4 describes a mold assembly for the production of cast aluminum engine blocks comprising a plurality of cylinder liners. The mold assembly is composed of a plurality of casting cores, wherein in particular for a positioning of the cylinder liners, a cylinder jacket core is used with a plurality of cylinder jackets, which cylinder jackets along their axial extent each have a taper of its outer diameter. The cylinder liners each have a tapering of the outer diameter adapted tapering of its inner diameter, which is greater by a multiple than the wall thickness of the cylinder liners.

It is the object of the invention to provide a method according to the preamble of claim 1 and a bushing according to the preamble of claim 5, wherein the cylinder liners can be particularly easily positioned and used just as easily as conventional long cylinder liners.

This object is achieved according to the invention in the method mentioned by the characterizing features of claim 1 and in the aforementioned cylinder liner by the characterizing features of claim 5.

An inventive method for producing a cylinder crankcase with a plurality of cylinder liners, comprising the steps of providing at least two cylinder liners each having a first cylinder head end and a second crankshaft end and a liner body, setting the cylinder liners in a mold and casting around the cylinder liners with a casting material is characterized characterized in that on each liner body, a strip of material is defined, which projects axially at least the second, crankshaft-side end of the cylinder liner.

By providing the material strip preferably formed of a rolled sheet with abutting edges on the cylinder liners, it is possible to easily design the liner body of the cylinder liner with a shorter axial extent compared to a conventional cylinder liner. Preferably, the cylinder liner formed in common from the liner body and the material strip has approximately the same length as a conventional cylinder liner. As a result, in the method for producing a cylinder crankcase already known tools that are suitable for the use of conventional cylinder liners, continue to be used. The relatively thin strip of material is melted during the casting and thus forms advantageous in the solidified Cylinder crankcase with the Umgußmaterial a common part. Further, it is advantageous that the compared to conventional cylinder liners shortened liner body leads to a reduction in the cost of the cylinder liner, since the liner body due to the thermal and mechanical demands on the cylinder surface must be made of a high quality and expensive material during the not belonging to the cylinder surface material strip can be made of a simpler material.

Preferably, the setting of the cylinder liner in the mold takes place in that the material strip is attached to a part of the mold. In a particularly preferred embodiment of the method, this part of the casting mold is a sleeve which has the same shape as in the known methods for conventional cylinder liners. The plugged cylinder liner circumferentially surrounds the sleeve. In particular, if the entire length of the cylinder liner formed from the liner body and the material strip corresponds to the entire length of a conventional cylinder liner, the attachment may provide for a particularly simple placement of the cylinder liner, since this process will not differ significantly from the placement of a conventional cylinder liner. The material strip of the plugged cylinder liner thereby protects the part of the mold, which is not covered by the liner body, from contact with the casting material, thereby increasing the life of the casting mold.

Preferably, the axial extent of the shortened liner body substantially corresponds to the length of the piston stroke within the cylinder crankcase. The cylinder liner is arranged in the cylinder crankcase, that the liner body is limited in its axial extent substantially to the travel of the piston skirt. Particularly preferably, the cylinder liner is placed so that the cylinder head side end of the liner body is positioned at the level of the cylinder head gasket. The one in the Cylinder crankcase cast, shortened compared to a conventional Zylinerlaufbuchse liner body is advantageously enclosed on its crankshaft side end face of the cylinder crankcase forming casting material. This counteracts in later operation of the engine a release of the cylinder liner of the cylinder block housing, since the liner body is not only connected veabunden circumferentially with the casting material, but is also supported on its crankshaft side end face of the casting material.

In a preferred embodiment of the method, the common length of the liner body and of the material strip of each cylinder liner substantially corresponds to the length of the respective cylinder bore.

Finally, in a finishing step following solidification and cooling of the cylinder crankcase, the strip of material associated with the trim is preferably removed from the cylinder bore. The method used for this purpose in the final machining is preferably a honing or boring of the cylinder bore or another, for example chip-forming machining of the cylinder surface such as internal turning.

In a preferred embodiment of the method, the cylinder liners are arranged in the mold in such a way that the liners are at least partially in contact with each other. It is preferably provided that the liner body are flattened on its outer side along the contact surface. Such a method allows a particularly space-saving arrangement of the cylinder liners, whereby engines with a correspondingly larger displacement can be built with the same size. Preferably, the cylinder liners are in particular arranged so that the material strips fixed to the liner body are not in contact with each other. The material strips, the crankshaft side of the liner body of the Cylinder liners protrude, thus can be well flowed around by the casting material or Umgußmaterial.

A cylinder liner according to the invention comprises a liner body and is characterized in that a strip of material is fixed to the liner body, which projects axially on at least one end face of the liner body. Preferably, the strip of material covers the inside of the liner body at least partially. The strip of material can then be attached to the liner body in a particularly simple manner by frictional connection, for example gluing, by positive engagement, for example by mechanical clamping, or by a combination of force and positive engagement. Particularly preferably, the material strip is circumferentially fixed to the inside of the liner body. In an alternative embodiment, the strip of material surrounds the outside of the liner body circumferentially.

Preferably, the material strip fixed to the liner body has a cylindrical shape coaxial with the cylinder liner. The outer diameter of the cylinder formed by the material strip and the inner diameter of the cylindrical liner body are preferably the same or aligned, so that the material strip has a tight fit in the liner body. Preferably, the cylindrical strip of material covers a partial surface of the inner side of the bushing and protrudes on an end face of the liner body in the axial direction from the liner body.

In a preferred embodiment, the cylindrically curved strip of material covers the entire inner surface of the liner body. Such a configuration allows a particularly uniform and smooth configuration of the inner surface of the cylinder liner.

In an alternative preferred embodiment of the cylinder liner of the liner body has a recess which is formed for receiving the strip of material. Preferably, the depth of the recess corresponds to the thickness of the material strip, so that a bushing according to the invention has a cylindrical inner surface which has a constant radius along the entire axial extent and overall has a very smooth and planar shape. Preferably, the depth of the recess and the thickness of the material strip are at most equal to the thickness of the material removed in a finishing step of the inner surface of a cylinder crankcase.

Preferably, the liner body consists of a spray-compacted material, which is in particular light metal or a light metal alloy. In particular, materials from the group consisting of aluminum, magnesium, aluminum-silicon alloys, aluminum-base alloys and magnesium-based alloys have been found to be suitable materials for the liner body and the process of spray compacting to be a manufacturing process for liner bodies particularly suitable. Preferably, the strip of material also consists of light metal or a light metal alloy, wherein the strip of material may in particular be an aluminum sheet. Such strips of aluminum sheet metal are simple and inexpensive to manufacture and well suited to their material properties such as the flexibility or the melting temperature.

Preferably, the strip of material is made of a different material than the liner body. This advantageously makes it possible to choose the material used for the material strip on the one hand and the liner body on the other hand according to the specific requirements in accordance with advantageous.

Particularly preferably, the strip of material consists of the same material as the casting material of the cylinder crankcase. During the molding of the cylinder liner with casting material, it comes to a Melting of the material strip, which leads to a particularly good connection of the material strip and the liner body.

Suitably, the thickness of the material strip preferably formed by a metal sheet is smaller than the wall thickness of the liner body. Preferably, the thickness of the material strip is less than 0.5 times, preferably less than 0.25 times the wall thickness of the cylinder liner body, more preferably even smaller thicknesses of the material strip used as 0.1 times the wall thickness of the cylinder liner body be, in particular between 0.05 and 0.15 times the wall thickness of the liner body. The choice of such a thin strip of material ensures that the strip of material can be completely removed from the cylinder bore in the final machining of a cylinder crankcase.

A method of making a short cylinder liner in accordance with the present invention includes the steps of spray-compacting a light metal or light alloy alloy bolt, extruding the bolt into a cylindrical tube to form the liner body, finishing at least a portion of the inner surface of the liner body in preparation for securing a strip of material , and setting a strip of material on the inside of the liner body.

In the manufacture of a bolt by spray-compaction and the extrusion of the bolt to form a cylindrical tube is a method known in principle for the production of cylinder liners. Hereby, the methods according to EP 0 858 517 B1 . EP 0 848 760 B1 and EP 0 871 791 B1 introduced by reference. What is new, however, is to machine the inner surface of the liner body to prepare it to receive a strip of material by frictional engagement, positive engagement, or a combination thereof. Preferably, a regular profiling is produced by the processing of the inner surface, in the form of a thread, a scale structure, plate-like projections and / or depressions or undercut depressions in the manner of a dovetail. By such a profiling of the inner surface of the material strip can be determined by pressing into the liner body well on this, in particular, a durable mechanical clamping between the strip of material and the liner body is obtained. Particularly preferably, a recess of an inner side of the surface is produced in the surface treatment, so that the material strip clamped in the liner body has the same inner diameter as the liner body itself. In an alternative preferred embodiment of the method, the material strip is fixed by gluing to the inner surface of the liner body.

In an alternative embodiment, the surface treatment is performed on the outer surface of the liner body, and the material strip is fixed to the outer surface of the liner body. This advantageously leads to an enlarged, crankshaft-side opening of the cylinder bore adjacent to the running surface of the piston, which contributes to an increased mobility of the connecting rod associated with the connecting rod.

Preferably, the axially extending edges of the cylindrically curved material strip abut each other so that they form a closed seam and the cylindrically curved strip of material has a total of a closed lateral surface.

Further advantages and features will become apparent from the following description of preferred embodiments and from the dependent claims.

Fig. 1

zeigt einen Längsschnitt durch ein erstes bevorzugtes Ausführungsbeispiel einer erfindungsgemäßen Zylinderlauf- buchse.

Fig. 2

zeigt einen Längsschnitt durch ein zweites bevorzugtes Ausführungsbeispiel einer erfindungsgemäßen Zylinderlauf- buchse.

Fig. 3

zeigt schematisch eine Detailansicht des mit X bezeichneten Ausschnitts der in Fig. 2 dargestellten Zylinderlaufbuchse.

Fig. 4

zeigt schematisch eine Detailansicht des mit Y bezeichneten Ausschnitts der in Fig. 1 dargestellten Zylinderlaufbuchse.

Fig. 5

zeigt eine alternative Ausgestaltung des in Fig. 4 gezeigten Details.

Fig. 6

zeigt eine weitere alternative Ausgestaltung der in Fig. 4 gezeigten Detailansicht einer erfindungsgemäßen Zylinderlaufbuchse.

The invention will be explained in more detail below with reference to the accompanying drawings based on preferred embodiments of the invention.

Fig. 1

shows a longitudinal section through a first preferred embodiment of a cylinder liner according to the invention.

Fig. 2

shows a longitudinal section through a second preferred embodiment of a cylinder liner according to the invention.

Fig. 3

schematically shows a detailed view of the designated X section of the in Fig. 2 illustrated cylinder liner.

Fig. 4

schematically shows a detail view of the designated Y section of the in Fig. 1 illustrated cylinder liner.

Fig. 5

shows an alternative embodiment of the in Fig. 4 shown details.

Fig. 6

shows a further alternative embodiment of in Fig. 4 shown detail view of a cylinder liner according to the invention.

In the Fig. 1 The cylinder liner 1 comprises a cylindrical liner body 2 and a material strip 3 fastened to the inner surface of the liner 2. The material strip 3 has an overall axial extent designated L1 and protrudes around the length L2 on the crankshaft side 4 of the liner body 2. The entire axial extent of the cylinder liner 1 is denoted by L. In the in Fig. 1 and 2 shown embodiments, the axial extent L1 of the material strip 3 is smaller than the axial extent of the liner body 2. In an alternative embodiment, the axial extent L1 of the material strip 3 but also be as large or larger than the axial extent of the liner body 2, in particular, if the material strip 3 extends up to the cylinder head side end face 7 of the liner body 2.

The clamping between the liner body 2 and the material strip 3 is particularly in Fig. 2 and 3 particularly easy to recognize. The inside of the liner body 2 shows a shark fin-like profiling 5, which forms by their undercuts a very good Verklammerung with the pressed into the liner body strip material 3. The profiling is rotatiönssymmetrisch along the entire of the strip of material covered inner surface formed.

In an alternative embodiment, not shown, the profiled area is not formed along the entire inner surface covered by the material strip, but only along rotationally symmetrical partial surfaces. The rotationally symmetrical partial surfaces are thereby interrupted in the axial direction of areas in which no special profiling is provided. Instead of the shark fin-like profiling shown, in alternative embodiments, other profiled shapes with or without undercuts are provided, which are, for example, a sawtooth profile or a dovetail-shaped profile.

In a further, not shown, alternative embodiment of the material strip is determined by a non-positive connection, for example by gluing, on the inside of the cylinder liner. In this embodiment, a profile-forming processing of the surface of the liner body is not necessary.

The in Fig. 6 shown liner body 2 has instead of profiling a recess 6 for receiving the strip of material 3. The inwardly facing surface of the material strip 3 and the inwardly facing surface of the liner body 2 thus form a common, planar surface. As can be clearly seen, the thickness of the material strip 3 is significantly smaller than the wall thickness of the liner body 2.

To produce a cylinder crankcase, the cylinder liner 1 with the material strip 3 projecting from the crankshaft-side end face 4 is plugged onto a part of a casting mold, so that the part of the casting mold is enclosed by the cylinder liner 1. The cylinder liner 1 is then encapsulated with liquid casting material so that at least part of the outer circumferential surface 8 of the liner body 2 is in communication with the casting material. In order to improve the connection of the liner body 2 to the casting material, a profiling or a surface coating improving the connection to the casting material may be provided on the outer jacket surface 8.

How special in 4 and 6 can be seen well, the end face 4a of the liner body 2 is substantially perpendicular to the axially extending outer surface of the strip of material 3. In an alternative embodiment, the end face 4a at an acute angle to the strip of material 3, as particularly well in Fig. 5 can be seen. This embodiment is particularly advantageous if, during the pouring of the cylinder liner 1 into a crankcase, the casting material penetrates from the crankshaft-side end face 4 into the casting mold. The casting material is then directed by the angled end face 4 a in the direction of the cylinder head end face 7 of the cylinder liner 1, wherein in comparison to the in Fig. 4 As shown education form less turbulence in the liquid casting material and thus a better connection of the cylinder liner 1 to the crankcase is possible.

Claims (15)

1. A method for the production of a cylinder crankcase having multiple cylinder liners (1), comprising the steps
   providing at least two cylinder liners (1), each having a first, cylinder head-side end, a second, crankshaft-side end and a liner body (2),
   affixing of the cylinder liners (1) in a mold, and
   casting a casting material around the cylinder liners (1),
   characterized in
   that a material strip (3), which projects axially at least from the second crankshaft-side end of the cylinder liner, is affixed to each liner body (2).
2. The method as claimed in claim 1, characterized in that each cylinder liner (1) is affixed by pushing the material strip (3) on to a part of the mold forming the cylinder bore, that the length of the liner body (2) is substantially equal to the length of the piston travel inside the cylinder crankcase, and that the joint length of the liner body (2) and the material strip (3) of each cylinder liner (1) is substantially equal to the length of the respective cylinder bore.
3. The method as claimed in claim 1 or 2, further comprising the step in which the material strip (3) is removed after casting around the cylinder liners (1).
4. The method as claimed in one of claims 1 to 3, characterized in that the liner bodies (2) of the at least two cylinder liners (1) are at least partially in contact with one another when arranged in the mold, and that the material strips (3) arranged on the liner bodies (2) are not in contact with one another.
5. A cylinder liner (1) comprising a liner body (2),
   characterized in
   that a material strip (3) is affixed to the liner body (2) and projects axially at least from one end face (4, 7) of the liner body (2).
6. The cylinder liner as claimed in claim 5, characterized in that the material strip (3) at least partially covers the inside of the liner body, and that the material strip (3) has a cylindrical shape coaxial with the cylinder liner (1).
7. The cylinder liner as claimed in claim 5 or 6, characterized in that the material strip (3) is affixed to the inside of the liner body (2) by a method of affixing which is selected from the group comprising mechanical coupling and frictional coupling.
8. The cylinder liner as claimed in one of claims 5 to 7, characterized in that a recess (6) is provided on the liner body (2) to accommodate the material strip (3).
9. The cylinder liner as claimed in one of claims 5 to 8, characterized in that the liner body (2) is composed of a spray-compacted material, and that the liner body (2) is composed of lightweight metal or a light alloy, and that the material strip (3) is composed of lightweight metal or a light alloy.
10. The cylinder liner as claimed in one of claims 5 to 9, characterized in that the material strip (3) is composed of a material different from that of the liner body (2).
11. The cylinder liner as claimed in one of claims 5 to 10, characterized in that the thickness of the material strip (3) is less than the wall thickness of the liner body (2), and that the axial extent (L1) of the material strip (3) is less than the axial extent of the liner body (2).
12. The cylinder liner as claimed in claim 11, characterized in that the thickness of the material strip (3) is less than 0.5 times the wall thickness of the liner body (2).
13. A method for the production of a cylinder liner (1) as claimed in one of claims 5 to 12, comprising the steps
    production of a billet by spray-compacting a lightweight metal or a light alloy,
    extrusion of the billet to form a cylindrical tube, in order to form the liner body (2), and
    surface machining of at least a part of the internal surface of the liner body (2),
    characterized in
    that the method further comprises the affixing of a material strip (3) to the inside of the liner body (2).
14. The method as claimed in claim 13, characterized in that the material strip (3) is affixed by a method which is selected from the group comprising pressing in and adhesive bonding.
15. The method as claimed in one of claims 13 or 14, characterized in that, after affixing, the material strip (3) has a cylindrical shape coaxial with the cylinder liner (1), and that the cylindrical material strip (3) has a seam running substantially parallel to the liner axis.

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