DE1917882A1 - Cylinder inner lining - Google Patents

Description

Cylinder Liners There are generally two types of cylinder liners. One type is added to a cylinder block afterwards, while the other is poured into the cylinder block. The invention relates to the second Type in which the cylinder inner liner is made of cast steel, a tubular Has body and a cylindrical inner wall and is poured into a cylinder block, a crankcase, a compressor housing or the like that consists of another Material as the inner lining, usually made of aluminum.

In the case of such inner linings, the outer circumference should be inaccurate or have irregularities of any kind on which the aluminum, if it is poured or sprayed around the inner lining, can adhere mechanically. Only 8o can achieve the best possible connection without non-adherent cells or air bubbles can be achieved. In contrast, a smooth outer surface is undesirable because the aluminum slips on her.

Known ZyZnder inner linings sometimes do not yet have one sufficiently large rough surface on their outside and are difficult to manufacture.

In contrast, it is the object of the invention that Disadvantage. to avoid the known cylinder liners, in particular to increase their tendency to be encapsulated and to simplify their production.

According to the invention, this object is achieved in the case of a cylinder inner liner the one mentioned at the beginning. Kind achieved by having the outside of the body with Ribs and grooves is provided and that the outwardly facing surfaces of the ribs are cylindrically machined and are concentric to the inner wall.

The ribs and grooves achieve that around the inner lining Cast aluminum is swirled on it and the surfaces melt together adheres that the rough surface is enlarged and that, as will be shown in the following is, the production is significantly simplified.

The swirling of the liquid metal, that with the rough surface the cylinder inner lining is in contact, prevents air pockets and non-stick areas between the aluminum cylinder and the inner liner, whereby hot spots and thermally insulating areas in which by connecting the product made from both metals should be avoided.

The best material for the inner lining is one for cylinders suitable steel with a content of less than 10 * free ferrite, a content of at least 90% pearlite and a content of uniform statistical distributed graphite, predominantly of type A, is used.

For the production of the inner lining it is provided that the tubular Body with an approximately cylindrical, rough inner wall and one with ribs and Grooved, rough outside is poured in a fixed form that the outward-facing surfaces of the ribs were machined cylindrically, that the inner lining is clamped on these surfaces and that under maintained am tensioning the inner wall of the body until concentricity is achieved the outward-facing surfaces is processed.

The casting in a fixed form makes the surfaces special rough. When the outwardly facing surfaces of the ribs are cylindrically finished the grooves in between remain rough. This roughness in interaction with the side surfaces of the ribs causes an excellent connection between the cast steel of the inner lining and the aluminum, from which a good durability of the cast cylinder results.

The finishing of the outward-facing surfaces of the ribs takes place advantageously by grinding without centering.

This processing can be carried out extremely quickly, as there is only one very small surface must be machined and because the lying between the ribs Grooves ensure quick removal of the lifted metal.

The outwardly facing tube surfaces of the ribs are after their cylindrical fine machining held in any suitable clamping tool, whereupon the machining of the inner wall can be done by drilling. This becomes a a piston receiving, exactly cylindrical and to the Exterior surfaces concentric bore created. The inner lining processed in this way has a uniform Wall thickness, which ensures uniform dissipation of heat in all areas of the inner lining and favors undisturbed operation of the engine, the air compressor or the like. Pouring the inner liner into a cylinder makes it a precision product of consistently high quality.

The invention as well as further refinements and advantages are in the the following explained in more detail with reference to the drawings.

They show: FIG. 1: A simplified cross section through a casting mold, in which two cylinder liners are cast; Figure 2: a perspective Partial section of the inner lining shown immediately after casting; figure 3: a perspective view of a partial section of the inner lining according to FIG cylindrical machining of the outwardly facing surfaces of the ribs; figure 4s a finished cylinder inner lining in a perspective view, in which the inner wall is concentric to the cylindrically ground surfaces is finely machined so that the walls have the same thickness on all sides; Figure 5: the plan view of a section of a further embodiment in which the ribs compared to the embodiment shown in Figure 4 greater spacing to have.

The sand mold 6 has, for example, an upper mold 8, a lower one Form 10, cores 12 (which are mostly not solid, but made of green molding sand like exist in the remaining parts of the mold) an inlet, inflow channels, a riser channel and downward channels, collectively indicated by the reference numeral 14 are.

The castings 16 form the during the manufacture of the inner lining first step. They have the form shown in Figure 2, but can also Have cast flanges 17.

The inner surface 18 of each casting has that characteristic of sand casting Roughness, which is indicated by a puncture ant. A similar surface roughness is found on the outside of the tubular body, which is both on the ribs 20 as indicated in the grooves 22 in between.

The tubular body 16, which has rough surfaces on all sides is then on its outside until breaking a cylindrical shape machined, this machining being done by grinding without centering and extends only onto the outwardly facing surfaces 24 of the ribs 20, such as can be seen from FIG. If the body is provided with a flange, a special grinding wheel required. The insides 26 and side walls 28 of the grooves 22 retain the rough surface given to them by the sand casting, which is also shown in FIG 3 is indicated by dots. As a result, on the one hand, there is a cylindrical surface created that can be grasped by a precision clamping tool while on the other hand, a sufficiently large rough surface remains available. In the cylindrical machining it is only necessary to find those points of the body to remove that exceed the desired scope, That The casting is held in a precision clamping tool further machined to produce a machined bore 180 in inner wall 18; Certain wall thickness tolerances can be adhered to. The editing the inner wall is preferably done by drilling. With the clamping, the grinding however, other machining methods can be used, though thereby the same precision is achieved.

In any case, the inner wall 18 is until it reaches the with concentricity / the outwardly facing surfaces at least some ribs 20 machined to a to ensure precisely concentric clamping during fine machining.

As is shown schematically in FIG. 5, the ribs 200 also have an overall smaller surface at a greater distance, so that the grooves 220 in between are wider than in the exemplary embodiment according to the figures 1 to 4 are.

The cost of particularly important grinding with no centering is low, since the removal of material onto the small, outward-facing surfaces the ribs is limited. The direct removal of chips also carries through the grooves 22 contribute to both speed and accuracy. The scored Accuracy is so high that there is practically no scrap. The connection with the cylinder casting is excellent thanks to the ribs and those obtained by the sand casting Roughness of the surfaces in the grooves. In addition, the axial course of the ribs contributes a derivative between two neighboring ones on the circumference, through the cylinder avoid cut openings.

Due to the special structure of the inner lining and the process for their production can be both chemical and physical metallurgical requirements are met for low wear and tear and long service life are to be fulfilled.

There will be an exact concentricity between the outside and the Inner wall of the machined surfaces achieved, the wall thickness within usual Tolerances remain the same, so that heat is transferred from the inner lining to the surrounding metal is derived uniformly. The inner lining retains even after processing their surfaces, to which the metal cast around them is swirled and sticks, thereby avoiding air inclusions and non-stick areas and an excellent mechanical connection between the two metals is achieved.

Claims (7)

Claims 1.) Cylinder inner lining made of cast beam with a tubular body and with a cylindrical inner wall, characterized in that the outside of the Body is provided with ribs (20) and grooves (22), and that the outwardly facing Surfaces (24) of the ribs (20) are cylindrical and concentric to the inner wall (18). 2. Inner lining according to claim 1, characterized in that the ribs (20) extend axially along the tubular body. 3. Inner lining according to claim 1, characterized in that the Surfaces (26,28) of the grooves (22) are left rough after the casting and are between the finely machined surfaces (24) extend practically uninterrupted. 4. Inner lining according to claim 1 to 9, characterized by the Use of a steel suitable for cylinders with a content of less than 10% free ferrite, a content of at least 90% pearlite and a content of uniform statistically distributed graphite, predominantly of type A, as material. 5. Method for producing a cylinder inner liner according to Claim 1, characterized in that the tubular body with an approximately cylindrical, rough inner wall (18) and with a rough one provided with ribs (20) and grooves (22) The outside is poured in a fixed Porm (6) that the outward facing Surfaces (24) of the ribs (20) are cylindrically finished that the inner lining is clamped on these surfaces (24) and that under maintained clamping the inner wall (18) of the body until concentricity with the after outside facing surfaces (24) is processed. 6. The method according to claim 5, characterized in that the fine machining the outwardly facing surfaces (24) is carried out by grinding without centering and that the rough surface (26,28) of the grooves (22) is left. 7. The method according to claim 6, characterized in that the machining the inner wall (18) is carried out by drilling. Blank page