JPH02175063A - Method for casting cylinder block having oil hole - Google Patents

Abstract

PURPOSE:To cast a cylinder block having oil hole by setting a core to the prescribed position to the fixed lower die together with an upper die and a die constituting part related to this and acting as advancing the remaining die constituting part to the fixed lower die. CONSTITUTION:The core for forming the oil hole positioned on a jig 23 at waiting position is positioned and held to the upper die 12 at high accuracy by fitting a core print part into fitting parts of front and rear dies 15, 16 as possible to advance/retreat, for example, making advancing posture, to the upper die 12. After that, the upper die 12 and the front and rear dies 15, 16 as advancing condition are shifted to molten metal pouring position. successively, these upper die 12 and the front and rear dies 15, 16 are set to the prescribed position to the fixed lower die 2. Therefore, only by this way, without executing the special positioning of the core to the fixed lower die 2, the core can be held under the sufficiently accurate positioning condition to the fixed lower die 2. Therefore, it is not necessary to machine the oil hole by forming the excess casting part, and the cylinder block having the oil hole can be cast.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for casting a cylinder block having oil holes, and particularly to a method for casting a cylinder block using a core for forming oil holes.

(Prior Art) As a conventional casting method, for example, there is a cylinder head casting method disclosed by the present applicant in Japanese Utility Model Application Publication No. 160969/1983.

This method uses a mold consisting of a fixed lower mold, a horizontal mold that moves horizontally forward and backward relative to the lower mold, and an upper mold that moves vertically forward and backward relative to the lower mold. ,
On the other hand, molten metal is compressed from a holding furnace placed below the lower mold into the casting space defined by the horizontal mold and the upper mold, each in the advancing position, and after the molten metal solidifies, the horizontal mold and the upper mold are in the retreating position. The cast cylinder head is then removed from the mold.

(Problem to be Solved by the Invention) By the way, when casting a cylinder block having an oil hole extending in the front-rear direction (in the axial direction of the crankshaft) using the above-mentioned conventional casting method, the oil hole is core(
For example, when attempting to form the core using a sand core or casting vibe, there was a problem in that it was difficult to hold the core in a predetermined position within the mold because the horizontal mold had to be moved forward and backward.

For this reason, conventionally, when manufacturing the above-mentioned cylinder block, blind holes were formed at the front and rear ends of the cylinder block using a horizontally protruding casting bottle, and these blind holes were communicated with each other using a drill. However, in this method, drilling with a drill requires a large volume of waste material to be processed.
During casting, the solidification of that part is delayed and a large number of bubbles remain, which tends to cause so-called cavities.There is also the problem that the cavities in the waste areas can cause oil leakage, and the hole drilling described above is difficult. Since this is necessary, there is a problem in that the manufacturing cost increases.

The present invention provides a casting method that enables the casting of a cylinder block using an oil hole forming core and advantageously solves the above-mentioned problems.

(Means for Solving the Problems) A method for casting a cylinder block having oil holes according to the present invention includes casting a cylinder block on a jig at a predetermined standby position when casting a cylinder block using a core for forming oil holes. After the core, which has been positioned and arranged, is held by other mold components in an advanced position with respect to the upper mold and transported to the pouring position, the core, together with the upper mold and its associated mold components, is placed under a fixed position. The mold cavity is set in a predetermined position relative to the mold, and the remaining mold components are moved forward relative to the fixed lower mold to form a mold cavity, and then the metal is poured into the mold cavity. It is something to do.

Incidentally, as the core, a sand core having a mandrel can be used.

When the above-mentioned sand core is used as the core, before removing the core sand from inside the cast cylinder block,
A shock is applied to the core metal, causing the sand core to collapse.

(Function) According to the above-described invention, the oil hole forming core positioned and arranged on the jig at the standby position is inserted into the insertion part of the front and rear molds that is in the advanced position and can move forward and backward with respect to the upper mold. After positioning and holding the upper mold with high precision by fitting the core baseboard part, move the upper mold and the front and rear molds in the advanced state to the pouring position, and place the upper molds at that position. By simply setting the front and rear molds in the predetermined positions relative to the fixed lower mold, the core can be held in a sufficiently accurate position relative to the fixed lower mold without any special positioning of the core relative to the fixed lower mold. Therefore, it is possible to cast or manufacture a cylinder block having oil holes without forming a dead wall part during casting and then drilling the dead wall part as in the prior art. It is possible to eliminate the risk of oil leakage due to the occurrence of crevices in the waste portion, and it is also possible to reduce the processing cost associated with drilling holes, thereby lowering the manufacturing cost.

Here, when a sand core with a mandrel is used as the oil hole forming core, the strength of the sand core can be sufficiently increased, so both ends of the sand core can be used as baseboards. can be held, for example, in a front-to-back manner, thereby making it possible to reliably position the elongated sand core.

When the above-mentioned sand core is used, by applying an impact to the mandrel before removing the core sand from the cast cylinder block, the sand core is efficiently and finely disintegrated in a short time. This makes it possible to easily and reliably remove the core sand from the sand core in a short time.

(Example) Examples of the present invention will be described in detail below based on the drawings.

FIG. 1 is a partially cut away perspective view of a cylinder block casting apparatus used in an embodiment of the casting method of the present invention, and FIG. 2 is a cross-sectional front view, right side view, and side view of the main parts thereof. It is.

In the figure, P1 is the pouring station, P2 is the waiting station adjacent to the pouring station P1 on one side, on the left side in the figure, and P3 is the waiting station on the other side of the pouring station P1, on the right side in the figure. Each mold exchange station is shown.

Here, the lower fixing plate 1 is arranged horizontally in the pouring station P1, and the fixed lower mold 2 is fixed on this lower fixing plate. A side mold 4 is provided in the center of the fixed lower mold 2 and is driven forward and backward from the left and right under the action of a horizontal cylinder 30, and a molten metal holding furnace 5 is arranged below the lower fixed plate 1. .

In addition, each station PI+P2+P mentioned above
3, a pair of track rails 6 are passed over the rails, and the track rails 6 support the running bogie 7 hooked thereto, and the running bogie 7 is connected to the waiting station P2 for mold exchange. Guide to travel to and from station P3. By the way, the traveling carriage 7 is provided with a motor 8 for driving the traveling carriage 7, and a mold mounting frame 10 is connected to the traveling carriage 7 by an elevating cylinder 9 so as to be able to be driven up and down. The vertical movement is guided by a plurality of guide rods 11 passing through it. The upper mold 12 is fixed to the center portion of the lower surface of the mold mounting frame 10, and the upper mold 12 is fixed to the lower center portion of the mold mounting frame 10, and the upper mold 12 is fixed to the lower surface center portion of the mold mounting frame 10.
A bore mold opening/closing cylinder 14 is provided for advancing and retracting the bore mold 13 from diagonally above the upper mold 12, and a front mold 15 and a rear mold are provided on the front and rear portions of the lower surface, as shown in FIG. 2(b). A front mold opening/closing cylinder 17 and a rear mold opening/closing cylinder 18 for horizontally advancing and retracting the mold 16 relative to the upper mold 12 are attached.

Here, a lifter 19 and a traverse rail 20 are respectively disposed in a standby station P2 adjacent to the left side of the pouring station P1.
extends in the front-rear direction via the standby station P2. Two carts, a core transport cart 21 and a work loading cart 22, are respectively engaged with the traverse rail 20, and a core setting jig 23 is mounted on the core transport cart.
A workpiece holder and a jig 24 are respectively positioned and placed on the workpiece loading cart. Each of these trolleys 21.2
2, each rotary actuator 25.26 is connected to the trolley 21.22 via a crank mechanism 27.28.
Based on the operation of , it is possible to travel from each end of the traverse rail 20 to a standby station position, in other words, a position directly above the lifter 19. Here, the lifter 19 operates when any of the carts is brought to a position directly above it, and moves the jig on the cart into engagement between the recess 29 provided there and the locate pin 30 of the lifter 19. It functions to raise it to a predetermined height at the bottom.

Furthermore, a running rail 31 extending in the front-rear direction is installed at the mold changing station P3, and a mold changing cart 32 is placed on this running rail.

The main parts of the casting apparatus as described above will be explained in detail below based on FIG. 3.4.

As shown in FIG. 3, a pouring spout 33 provided in the fixed lower mold 4 on the lower fixed plate is connected to the first mold through the feeder 34 and the stalk 35. While connected to the molten metal holding furnace 5 shown in FIG. 2, a box-shaped bracket 36 is attached to the lifting cylinder 9.
The lower mold 12 is mounted on the lower surface of the mold mounting frame 10 connected via the upper mold mounting plate 37, which also functions as a spacer, by a clamper (not shown) having an automatic attachment/detachment function. An ejector turbine 38 that is disposed vertically through the mold is connected via a connecting plate 39 to a product extrusion cylinder 40 that is attached to the upper surface of the mold mounting frame IO.

Further, the bore mold 13 is connected to a mold mounting plate 41 provided at the rod end of the bore mold opening/closing cylinder 14 by a clamper (not shown) which also has an automatic attachment/detachment function, and the tip peripheral surface of the bore mold 13 is , as shown in Figure 3(b),
A vacuum pump 42 includes a solenoid valve 43 and a liner adsorption circuit 44.
A suction opening 45 communicates with the vacuum pump 42 through a solenoid valve 46 and a gas suction circuit 47, and a baseboard portion of a water jacket core 48, which will be described later, is connected to the vacuum pump 42 through a solenoid valve 46 and a gas suction circuit 47. Exhaust gas openings 49 are provided for sucking and removing generated gas from the exhaust gas openings 49, respectively.

Preferably, a groove 51 into which the water jacket core 480 and baseboard 50 can be fitted is provided in the diameter-reduced end wall of the bore mold 13.
This advantageously improves the gas suction efficiency at the exhaust gas opening 49.

Further, here, the front and rear molds 15.16 are also attached to the mold mounting plates 52, 5 provided at each rod end of the opening/closing cylinder 17.18, as shown in FIG. 4(a).
3 are connected by a clamper (not shown) similar to that described above, and insertion holes are provided for fitting the end portions of the baseboards 50, 54 of the water jacket core 48 into the mold surfaces of the molds 15, 16. 55 and 56 respectively.

In addition to the above configuration, the mold surfaces of the front and rear molds 15 and 16 have an oil hole in the core made of a mandrel 57 and core sand 58 as a core for forming the oil hole, as shown in FIG. 4(b). An insertion hole 60 for fitting the end portion of the child 59 is also provided, and the insertion hole 60
In this step, an exhaust gas passage 61 communicating with the outside of the mold is opened.

In this example, both side molds 4 are connected to a mold mounting plate 62 provided at the rod end of the horizontal cylinder 3 in the same manner as each of the other molds.

In each of the mold components constructed in this manner, the bore mold 13 and the front and rear molds 15 and 16 are placed in an advanced position relative to the upper mold 12, and the upper mold 12 is placed in a predetermined position relative to the lower mold 2. By moving the side mold 4 closer to the lower mold 2, a mold cavity 63 having a desired three-dimensional shape is formed between the molds.
will be divided.

Below, the operation of the above-mentioned casting apparatus will be explained.

For example, when manufacturing a cylinder block for a V-type 8-cylinder engine, first, the core carrier 2I and the core setting jig 23 are placed at one end of the traverse rail 20 as shown in FIGS. 1 and 2(b). With the jig 23 positioned as shown in FIG. Figure 5 (
Eight liners 64 made of cast iron as shown in the perspective view in a) and two water jacket cores 48 as shown in FIG. At the same time, the jig 23 is heated to a certain temperature and positioned and placed on the platform 23a having a V-shaped groove in the center of the jig 23, as shown in FIG.
) One of the oil hole cores 59 shown in ) is also heated to 500°C.
Heating it to the front and back temperatures and positioning it. The oil hole core 59 here is a core metal 5 which is a steel pipe with many small holes.
It is a sand core formed by press-forming core sand 58 into a cylindrical shape around the mold 15.
It is slightly tapered in order to be inserted into the insertion hole 60 of No. 6.

With such a structure, the oil hole core 59 has sufficient strength for positioning and holding within the mold and during pouring, and also has good air permeability.

Next, the core conveying cart 21 is moved to the standby station P2 based on the operation of the row reactor 25, and there, the core setting jig 23 is positioned and placed there, and the liner 64 and the water jacket are moved to the standby station P2. Core 4
8 and the oil hole core 59 are raised by the lifter 19 to the upper limit position shown by the imaginary line in FIG. 6(a).

At this point, the upper mold 12, the bore mold 13, and the front and rear molds 15.
16 is a bore type 13 as shown by the solid line in FIG. 6(a).
With the front and rear molds 15 and 16 in a backward posture with respect to the upper mold 12, they are waiting at the lower limit position based on the extension stroke of the lifting cylinder 9.

Thereafter, based on the operation of the bore type opening/closing cinder 14, the bore type 13 is advanced relative to the upper mold 12, causing the bore type 13 to enter into the liner, and at the same time, the third
The electromagnetic valve 43 shown in FIG. 3(b) is opened, the suction opening 45 is communicated with the vacuum pump 42, and each liner 64 is vacuum-adsorbed onto the circumferential surface of the bore mold 13.

Here, as shown in FIG. 7, the inner peripheral surface of the liner 64 has a slope corresponding to the draft angle of the entry portion of the bore mold 13. While the entry into the liner 64 is extremely smooth, when the bore mold 13 reaches its advancement limit, the accuracy of the liner 64 relative to the bore mold 13 is determined based on the close contact of the liner 64 to the circumferential surface of the bore mold. In addition to accurately positioning, insertion of molten metal between the two is completely prevented.

In addition, here, the front and rear molds 15 and 16 are also simultaneously connected to the upper mold 12.
By moving the baseboards 50° 54 of the water jacket core 48 on the jig into the insertion holes of the front and rear molds 15 and 16, as shown in FIG. 4(a), 55, 56, and fully insert both ends of the oil hole core 59 on the jig into the insertion hole 60 of the front and rear molds 15, 16, as shown in FIG. 4(b). By entering the water jacket core 48 and oil hole core 59, the water jacket core 48 and oil hole core 59 are accurately positioned and securely held.

In this way, after the liner 64, water jacket core 48, and oil hole core 59 are positioned and held with high precision by the bore mold 13 and the front and rear molds 15, 16, the contraction stroke of the lifting cylinder 9 The mold mounting frame 10 is attached to the bore mold 13 and the front and rear molds 1.
5. '16, and in turn, together with the liner 64, the water jacket core 48, and the oil hole core 59, are lifted to the position shown by the imaginary line in FIG. , liner 64
, the water jacket core 48, and the oil hole core 59 are accurately positioned at the pouring station P1 position, as shown by solid lines in FIG. 6(b).

Furthermore, based on the extension stroke of the lifting cylinder 9 again, the upper mold 12, the bore mold 13, and the front and rear molds 15.
16 gradually lowered, and finally they were moved to the position shown in Fig. 8 (
As shown by the imaginary line in a), the liner 64 held by each of the bore mold 13 and the front and rear molds 15 and 16 by accurately setting it at a predetermined position relative to the fixed lower mold 2;
The water jacket core 48 and the oil hole core 59 are also set at predetermined positions with respect to the fixed lower mold 2 with high precision, and then the horizontal cylinder 3 moves the side mold 4 to the fixed lower mold 2.
By advancing the fixed lower mold 2, as shown in Fig. 3.
As shown in (a), a mold cavity 63 having a desired three-dimensional shape is defined between each mold.

For such a mold cavity 63, the molten metal in the molten metal holding furnace is transferred to the stalk 35, the feeder 34 and the pouring port 33.
At the same time, combustion gas and other gases generated in the cavity are removed from the water by closing one solenoid valve 43 and opening the other solenoid valve 46 between the pouring and solidification of the molten metal. Passing through the exhaust gas opening 49 from the skirting board 50 of the jacket core 48, suction and exhaust with the vacuum pump 42, and passing through the center through the small hole in the mandrel 57 of the oil hole core 59.
Natural exhaustion through the exhaust gas passage 61 sufficiently prevents gas defects from occurring in the cylinder block as a cast product.

Here, after the molten metal has completely solidified to form the required cylinder block, first, the side mold 4 is retreated relative to the fixed lower mold 2, and then the upper mold 12,
The bore mold 13 and the front and rear molds 15.16 are lifted together with the cylinder block W, as shown by the solid line in FIG. As shown by the imaginary line in FIG. 8(b), it is transported by the traveling cart 7 to the waiting station P2, and at that position, the elevating cylinder 9 is extended and stroked, as shown by the solid line in FIG. 8(b). , bring them to their lower limit positions.

Furthermore, after that, by operating the lifter 19 on the work loading trolley 22 that has been moved in advance on the traverse rail to the standby station P2 position as shown in FIG. 8(b), the workpiece is positioned and placed on the trolley. For the workpiece receiver, the jig 24 is raised to the position of the imaginary line in the figure, the cylinder block W is temporarily received by the jig 24, and the bore die 13 is moved backward as shown in the figure, and the front and rear die (not shown) are moved. 15 and 16 to cause the cylinder block W to adhere only to the upper mold 12, and then, by operating the product extrusion cylinder 40, the eject turbine 38 is projected from the upper mold 12. As a result, the cylinder block W is released from the upper mold 12 thereof.

In addition, during such mold release, damage to the cylinder block W can be extremely effectively prevented by, for example, making the ejection speed of the ejector turbine 38 and the descending speed of the work receiver jig 24 the same.

The workpiece receiving jig 24 that has received the cylinder block W in this way is positioned again on the workpiece loading truck by the lifter 19, and then moved to one end of the traverse rail 20 by the truck 22. The cylinder block W is transferred as shown in FIG. 1, and then handed over to the next process as shown in a perspective view in FIG. 9(a) and in a vertical sectional view in FIG. 9(b). However, at this stage, although not shown, the water jacket core 48 and the oil hole core 59 still remain in the cylinder block W.

Therefore, in the next step, sand is removed from the water jacket core 48 and the oil hole core 59 in the cylinder block W. In removing the sand, the oil hole core 59 is removed by applying an impact to the mandrel 57 with a hammer or the like to collapse the core sand 58. In this way, the core sand 58 is efficiently and finely disintegrated in a short time, and therefore the core sand 58 and the mandrel 57 of the oil hole core 59 can be easily and reliably removed in a short time. .

When sand removal from the cores 48 and 59 is completed, a water jacket (not shown) and an oil hole 0 extending in the longitudinal direction of the cylinder block are formed in the cylinder block W.

Therefore, according to the above-mentioned casting method, the cylinder block W having 0 oil holes can be used without forming a dead wall portion during casting and then drilling the dead wall portion as in the prior art.
Since it can be cast, it is possible to eliminate the risk of oil leakage due to the formation of hollow holes in the waste portion, and also reduce the processing cost associated with drilling holes, reducing manufacturing costs. .

In addition, in the above-mentioned apparatus, when replacing each mold, for example, the fixed lower mold 2 removed from the lower fixed plate 1 and the side mold 4 removed from the mold mounting plate 62 are replaced with the upper mold 12, the bore mold 13, and Together with the front and rear molds 15 and 16, they are transported to the mold exchange station P3, where they are lowered onto the mold exchange trolley 32 and removed onto the trolley. The upper mold is mounted on the mold mounting frame 10, the bore mold and the front and rear molds are respectively mounted on the cylinders 14, 17, 18, and the lower mold and side mold are attached to the pouring station Pl.
There, the lower mold and the side mold are attached to the lower fixing plate 1 and the cylinder 3, respectively.

Although the present invention has been described above based on the illustrated example, the mold changing station P3 can be omitted from the above, and the exhaust gas opening 49 formed in the bore mold 13 can also be omitted. Also, the baseboard 50.54 of the water jacket core 48 and the insertion hole 55 of the front and rear molds 15°16
．． It is also possible to use only one of 56.

Furthermore, in the above example, the oil hole core 59, which is a sand core, is used as the oil hole forming core, but a metal pipe that is cast inside the cylinder block W and remains as it is may be used as the oil hole forming core. In this case, it is not necessary to remove sand from the core in the next step.

(Effects of the Invention) Thus, according to the method for casting a cylinder block having oil holes of the present invention, there is no need to form a dead wall portion during casting and then drill holes in the dead wall portion as in the prior art. , it is possible to cast or manufacture a cylinder block having oil holes, thereby eliminating the risk of oil leakage due to the formation of cavities in the hollow parts, and reducing the manufacturing cost associated with drilling holes. can reduce manufacturing costs.

Here, when a sand core with a mandrel is used as the oil hole forming core, the strength of the sand core can be sufficiently increased, so both ends of the sand core can be used as baseboards. can be held, for example, in a front-to-back manner, thereby making it possible to reliably position and hold the elongated sand core.

When the above-mentioned sand core is used, by applying an impact to the mandrel before removing the core sand from the cast cylinder block, the sand core is efficiently and finely disintegrated in a short time. This makes it possible to easily and reliably remove the core sand from the sand core in a short time.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating a casting apparatus used in an embodiment of the casting method of the present invention with a part cut away; FIG. 2 is a sectional front view of the main part of the apparatus shown in FIG. Figure 3.4 is an enlarged view showing the main parts of the device, and Figures 5 (a), (b) and (C) are perspective views showing the liner, water jacket core and oil hole core. Figure, 6th
8 and 8 are diagrams illustrating the casting process of the present invention, FIG. 7 is an enlarged view showing the relationship between the liner and the bore mold, and FIGS. 9 (a) and (b) are illustrations of the cylinder block. FIG. 2 is a perspective view and a vertical sectional view. Pl... Pouring position P2... Standby position W.
... Cylinder locked ... Lower fixing plate 3 ... Horizontal cylinder 5 ... Molten metal holding furnace 7 ... Traveling truck 9 ... Lifting cylinder 12 ... Upper mold 14 ... Bore type opening/closing cylinder 15 ... Front mold 17 ... Front mold opening/closing cylinder 19 ... Lifter 23 ... Core setting jig 43 ... Solenoid valve 45 ... Suction opening 48 ... Water jacket 50, 54. ... Baseboard 59 ... Oil hole core To core 55, 56.60 ... Insertion hole 64 ... Liner 0 ... Oil hole 2 ... Fixed lower mold 4 ... Side mold 6... Track rail 8... Motor 10... Mold mounting frame 13... Bore mold 16... Rear mold 18... Rear mold opening/closing cylinder 21... Core conveyance truck 42...・Vacuum pump 44... Litchi adsorption circuit (a) 56- Insertion ■ Fig. 4 (b) Fig. 5 (a) (b) (C) 4θ -

Claims (1)

[Claims] 1. When casting a cylinder block using a core for forming oil holes, the core, which is positioned on a jig at a predetermined standby position, is placed in an advanced position with respect to an upper mold. After being held by other mold components and transported to the pouring position, the core, together with the upper mold and its associated mold components, is set in position relative to the fixed lower mold, and then 1. A method for casting a cylinder block having an oil hole, the method comprising: pouring metal into a mold cavity in a state in which the remaining mold components are moved forward to form a mold cavity. 2. The method for casting a cylinder block having oil holes according to claim 1, wherein a sand core having a mandrel is used for the core. 3. According to claim 2, the sand core in the cast cylinder block is disintegrated by applying an impact to the mandrel, and the sand in the sand core is removed from the cylinder block. A method for casting a cylinder block with oil holes.