JP3023031B2 - Method and apparatus for manufacturing cylinder for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cylinder of an internal combustion engine and an apparatus for implementing the method.

[0002]

2. Description of the Related Art The development of internal combustion engines which are oriented to higher and higher specific powers has led to the problem that the cylinder liner, in particular the upper region, is subjected to higher and higher stresses due to pressure and temperature. This creates a demand for the cylinder liner to be made of high strength steel. However, at the same time, there is a demand that the sliding characteristics of the piston ring on the cylinder liner surface should not be reduced as compared with those obtained with gray cast iron. This dual need has conventionally been met by centrifugally depositing a gray cast iron sliding layer on the inner surface of the cylinder liner. The disadvantage of this method is that very long cooling times are required after centrifugal welding in order to guarantee the required quality of the composite cast cylinder liner. Furthermore, in this process, in which the melted material and the material, which is partially in the solidification phase, are interconnected, large quality fluctuations occur which significantly increase the failure rate.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to avoid the disadvantage of long cooling times and to produce a cylinder-to-grey cast iron connection at low cost and accurately. It is to provide a manufacturing method and an apparatus.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is to provide a mold comprising an outer mold and a core made of an inorganic mold material, heating a steel ring which is inserted into the mold and joined with gray cast iron. For the installation of the heat source working in the mold, insert the steel ring to be joined with gray cast iron into the mold, insert the core into the outer mold, close the mold, fill the mold with protective gas,
Heating a steel ring to an incandescent state in a closed mold, pouring molten gray cast iron, cooling a steel ring fused to a gray cast iron liner, and working in a mold for a cylinder for an internal combustion engine, A mold configured to be capable of mounting a heat source, inserting a steel ring to be joined with gray cast iron, filling with protective gas and heating without damage before casting;
The problem is solved by an apparatus for manufacturing a cylinder for an internal combustion engine, comprising: a heat source for heating a steel ring.

[0005] Advantageous embodiments of the method according to the invention are described in claims 2 to 8.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the drawings showing an embodiment of a cylinder manufacturing apparatus according to the present invention.

FIG. 1 shows, in cross section, a mold 1 and an outer mold 2 made of an inorganic mold material for vertical casting therein. A subordinate core 3 is mounted in the center of the outer die 2. The intermediate space which forms the mold 4 between the core 3 and the outer mold 2 includes a steel ring 5 for providing a gray cast iron sliding layer along the inner surface and an induction coil 6 surrounding the steel ring 5.
Is selected to be concentric with the core 3 to be inserted later. The induction coil 6 is fixed in the outer mold 2 by refractory concrete so that the hollow chamber 7 remains between the inner surface of the steel ring 5 and the outer surface of the core 3, and the hollow chamber 7 accommodates iron forming a gray cast iron layer. Serves as the lower part of the mold 4 for The cavity 8 present above the steel ring 5 forms the remaining cylinder liner outer mold as the upper part of the mold 4. The mold 4 is filled with a protective gas such as argon. Induction coil 6 configured tubular for cooling water guidance
Power supply conductor 9 and an induction coil 6 also having a tube section
Extend in the mold material of the outer mold 2. The surface portion of the core 3 facing the steel ring 5 is provided with a chamotte plate 10 for protection against thermal radiation.

The steel ring 5 is heated in the mold 4 to an incandescent state by an induction coil 6. Immediately after that, the mold 4 is the gate 1
1 is filled with the molten gray cast iron, the gray cast iron being fused to the incandescent steel ring 5. After the composite material has cooled, the material breaks the mold 4 and is removed for further processing.

In contrast to the embodiments described above, the preheating of the steel ring 5 can also be carried out in another way, for example by introducing a flame gas on the back of the steel ring 5 or by the principle of resistance heating. In order to further guarantee auxiliary oxidation protection,
The steel ring 5 can be provided with a protective layer of nickel, tin or another suitable material on its inner surface prior to its insertion into the mold 4.

[0010]

The method for manufacturing a cylinder liner described above with the most important steps has the following advantages. The preheating of the steel ring is locally limited between the molten iron and the steel ring, thus preventing only an unfavorable fusion welding from taking place. The preheating of the steel ring prevents different amounts of shrinkage due to different temperatures and thus the occurrence of shrinkage cracks between the two materials to be joined; The preheating of the steel ring, on the contrary, is based on the somewhat larger shrinkage of the steel compared to gray iron, resulting in a combination of fusion welding and shrink fit. The introduction of a protective gas into the mold 7 prior to the start of the preheating of the steel ring prevents the formation of an oxide film on the steel ring surface which prevents a reliable fusion of the two materials. Almost insurmountable difficulties such as preheating of the steel ring without oxide coating, insertion of the steel ring into the mold, closure of the mold and subsequent casting of molten iron are ready for casting under protective gas. It is overcome by preheating the steel ring in the mold. -The reproducible and precise location and formation of the bonding zone between steel and gray iron is an important quality advantage and significantly lowers the cost of failure compared to centrifugation.

[Brief description of the drawings]

FIG. 1 is a half sectional view of an embodiment of a cylinder manufacturing apparatus for an internal combustion engine according to the present invention.

[Explanation of symbols]

 2 Outer die 3 Core 4 Mold 5 Steel ring 6 Induction coil

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-61-232039 (JP, A) JP-A-4-135496 (JP, A) JP-A-3-138070 (JP, A) West German patent application published 1426111 (DE, A1) (58) Fields studied (Int. Cl. ⁷ , DB name) B22D 19/08 B22D 27/04

Claims (9)

(57) [Claims] 1. A mold comprising an outer mold and a core of an inorganic mold material is manufactured, and works in a mold for heating a steel ring inserted into the mold and joined with gray cast iron. Attach heat source, insert steel ring to be joined with gray cast iron into mold, insert core into outer mold, close mold, fill mold with protective gas, incandescent steel ring in closed mold A method for producing a cylinder for an internal combustion engine, comprising: heating, casting molten gray cast iron, and cooling a steel ring fused to a gray cast iron liner. 2. The method according to claim 1, wherein the heating of the steel ring is performed by an induction coil. 3. The method according to claim 1, wherein the heating of the steel ring is performed by means of a flame gas. 4. The method according to claim 1, wherein the heating of the steel ring is performed by the principle of resistance heating. 5. The method according to claim 1, wherein the inner surface of the steel ring is provided with an antioxidant layer prior to insertion into the mold.
5. The method according to one of the above items 4 to 4. 6. The method according to claim 5, wherein a nickel layer is coated as an antioxidant layer. 7. The method according to claim 5, wherein a tin layer is coated as an antioxidant layer. 8. The method as claimed in claim 1, wherein argon is used as the protective gas. 9. A mold configured to be capable of mounting a heat source working in the mold, inserting a steel ring to be joined with gray cast iron, filling with protective gas and heating without damage before casting, and a steel ring. An apparatus for manufacturing a cylinder for an internal combustion engine, comprising: a heat source for heating a cylinder.