DE532267C - Method and device for the production of cylinder cores and pistons - Google Patents

Description

Method and device for the production of cylinder cores and pistons The invention relates to a method for producing cylinder cores and pistons made of cast iron or cast steel for fuel powder machines, their running surface should be hard. The surfaces of cylinder sleeves and pistons rubbing against each other and piston rings must have the hardest and most wear-resistant surface possible on piston engines that process dusty gases, i.e. in the case of pulverized coal engines.

It is known to cool castings faster by keeping the mold cool, especially at the points of thicker wall thickness so that they stay hot longer Cool spots evenly with the spots of thinner wall thickness and tension can be avoided in the finished piece. Has to achieve a dense, homogeneous cast it has been proposed to gradually cool the cast, which is kept hot. In the manufacture of gun barrels you use a metal core that you go through intensive cooling protected from destruction. The cooled metal core causes a faster one Cooling and hardening of the inner surface of the pipe. But goes with the later boring of the metal core and the machining of the pipe this hardness layer is lost again.

The method according to the invention has a route for manufacture from cylinder cores and pistons for fuel powder machines to those obtained by quenching to keep the obtained hard surface skin usable. Immediately upon generation hard surface saves a later special hardening process, cheaper So the production. According to the invention, in or around a core after pouring of the liquid metal introduced a coolant, which at a time when the The cast metal is still hot enough to harden, the cast metal cools down and hardens quickly. The core is made of a material that becomes thick after cooling Easily 'can be removed without damaging the casting or even by the coolant itself is destroyed, so that the coolant then directly hits the hot walls the casting can act. In the latter case, there is a further reduction in price the production achieved by the fact that the work for the often laborious time-consuming Removal of the core comes in omission.

The drawings represent exemplary embodiments, namely Fig. Z the casting device for a cylinder core a, the inner running surface b of which is to become hard, as far as the piston rings slide on it, Fig.2 the casting device for a piston whose outer running surface is to be hard .

Fig. 3 shows the casting device for a hollow cylinder whose outer jacket surface is to become hard and from which the piston rings will later be cut out should be. Fig. I shows one inserted into the mold a Core c, which can be made of clay with straw and manure in the usual way. The core c is made hollow in the upper part, so that only a thin core jacket d the casting material supports. In the cavity e of the core c a pipe is finely guided up to the bottom, with injection holes g, through which a cooling liquid after opening the valve h can be injected against the core mantle d.

Once the casting has taken place, valve h is opened after a while, and the cooling liquid can thus act on the core jacket and the casting material. The coolant fills the cavity e quickly, taking the one given off to the core jacket Heat on, cools the core mantle and thus also frightens the casting material on the inside away. After a short time it penetrated the core mantle itself and destroyed it this and then comes into direct contact with the hot cast iron. This happens, while the metal is still glowing warm, so still a temperature necessary for hardening owns. This vigorous cooling of the inside gives the cylinder liner the desired hardness on the running surface. A shattering of the cylinder core, like that often happens in chilled cast iron due to the expanding iron core, cannot occur because the core still remaining inside is contracting Casting does not offer any resistance worth mentioning.

In this process just explained, the core jacket d must be sufficient be made hard to absorb the external pressure of the hot casting material. This is not necessary if you wait until the casting material has solidified somewhat, in the cavity e leaves an inner core which fills this cavity. The inner core is then quickly removed and the tube f inserted in order to remove the Quench casting. It is of course also easily possible to use the cylinder liner according to this procedure. instead of watering the area standing up, or the facility to meet in such a way that the shape is reversed, as drawn, prepared and that. Spray tube for the cooling liquid is introduced into the cavity from below. What is achieved with this is that the core material is not destroyed when the core jacket is destroyed comes to rest on the bottom of the cavity c and fills the cavity, but falls out.

Fig.2 basically shows the same procedure, only the setup is Taken here in such a way that the core jacket k wraps itself around the cast piston m on the outside. Around the core jacket k there is an annular space, which in the drawing of the outer core o is filled out. After the casting has been completed, this outer core is removed and the Ring line w, indicated by dash-dotted lines, with the supply line s for the cooling liquid brought into the annulus o. From spray holes on the inside of the ring main w here too the cooling liquid is sprayed onto the core jacket k, this and thus the outer piston wall is cooled, then after some time the core jacket is destroyed and the outer piston wall due to the cooling water jets which now hit it directly quenched and hardened.

Fig.3 of the drawing differs essentially from Fig.2 only in that the outer core jacket v is traversed by a cooling water pipe coil around the shape z of the cylinder. The core material around the surface of the cylinder z to be hardened is energetically cooled as a result, and the hot, poured metal is quenched on the cold mold wall and becomes hard.

The device can advantageously also be attached to the first two figures, namely the cooling coil t is placed in the core jacket d in Fig. I or in the core jacket k in Fig. 2. The cooling coil then forms a welcome one for the thin core jacket Support frame, which absorbs the casting stresses when cooling. The cooling coil can also be provided with injection holes at suitable points in order to allow the coolant to exit and to act directly on the core jacket after the separating core material has been removed.

Another variant of the device according to Fig. I (indicated by dash-dotted lines) there may still be the fact that the cooling device is the same as a support axis for the partially hollow inner core is carried out, so that the usual for stiffening serving core iron can be dispensed with. The inner core is thereby used during manufacture the shape and protected from breaking during transport and gets stronger in the shape Hold and better leadership.

Claims (3)

PATENT CLAIMS: i. Process for the production of cylinder cores and pistons from cast iron or cast steel for fuel powder machines, the running surface of which should be hard, characterized in that in a cavity (e, o) in or around a core of destructible mass (c, k) after the pouring of the liquid Metal a coolant is introduced, which cools and hardens the cast metal while destroying the core. - 2. The method according to claim r, characterized characterized in that the cavities in the core during pouring with a matching Core to be filled, which is removed after casting to make room for the coolant to release. 3. Device for carrying out the method according to claim r and 2, characterized in that 'that a pipe coil with spray holes for the cooling liquid is stored in the core mantle.