JP2000042708A - Metallic mold device for manufacturing cylinder block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic mold device for manufacturing a cylinder block, with which the setting of a placed core into the metallic mold is easily executed and the taking-off of the placed core from a water jacket is easily executed without using a special jig and the design of a die part for water jacket is comparatively facilitated and the developing part of burr is few and the developed burr can easily be removed and the area of a bridge part can be secured largely and the placed core can simply be manufactured. SOLUTION: In the die part 30 for water jacket, a notched part 31 is formed, and in the notched part 31, one piece of the placed core is slid and fitted. The end surface 20a of the top deck side and end surface 20b of the crankcase side of the placed core are inclined to form a draft, and the bottom part 31c of the notched part has the same slope as the end surface 20a of the top deck side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold apparatus for manufacturing a cylinder block, and more particularly to a mold apparatus for manufacturing a cylinder block having a core.

[0002]

2. Description of the Related Art In order to cool an internal combustion engine, a water jacket surrounding a plurality of cylinder liners arranged in parallel is formed in a cylinder block. Also, for the purpose of reducing engine vibration and reinforcing the cylinder block, a so-called closed deck type cylinder block in which a bridge portion covering a part of the opening end surface of the water jacket on the top deck side of the cylinder block is known. I have. A crankcase is provided on the opposite side of the top deck.

[0003] In casting a cylinder block, a die for a water jacket is arranged inside a die for defining the outer shape of the cylinder block, and a projection for a cylinder bore is arranged inside the die for a water jacket. A water jacket is formed by pulling out the water jacket die. However, since a bridge portion is formed on the top deck side by casting, in order to pull out the water jacket dice portion, it is necessary to arrange a placement core at a portion corresponding to the bridge portion.

In Japanese Unexamined Patent Publication No. 9-70645, a plurality of cutouts extending in the axial direction of a cylinder liner are formed in a water jacket forming die, and are fitted into respective cutouts of the die to form a bridge. A combined core is provided. The laying core is formed of a solid (solid) iron-based material, and each of the plurality of laying cores has a two-part structure, and the divided surface extends in the axial direction of the cylinder liner. As each of the two split cores moves away from the split surface in the circumferential direction of the water jacket, a draft is formed in which the upper and lower surfaces of the split core expand in opposite directions to each other. The sliding core having a two-part structure has a sliding gradient that gradually becomes thicker as the distance from the dividing surface in the circumferential direction of the water jacket increases. A projection for forming an opening is provided on the bottom surface of the notch so as to protrude therefrom. When the placement core is disposed in the notch, the lower surface of the split placement core is placed on the projection, and It is set in the notch so that the division surface is located on the projection. Therefore, a gap is provided between the bottom surface of the cutout portion and the lower surface of the placing core due to the presence of the convex portion, and the bridge portion is formed by filling the gap with the molten metal.

[0005] After the mold for manufacturing the cylinder block is opened, the water jacket die is pulled out with the placing core remaining in the water jacket. The projection forms a hole in the bridge of the cylinder block. When the jig is inserted into the hole, the halves divided into two from the dividing surface are pushed open in opposite directions to each other, and each of the halves of the two halves is rotated around the lower surface corners as a center of rotation. By displacing the upper surface of the placement core from the bridge portion, a two-piece placement core can be taken out from the upper end opening of the water jacket.

In Japanese Patent Publication No. Hei 7-108449, in order to provide a bridge on the top deck of a cylinder block, a hollow metal placing core is fitted into a notch of a die for forming a water jacket. After the bridge portion is formed on the top deck side end surface of the placement core, the water jacket die is pulled out while leaving the placement core in the water jacket. At this time, both end faces in the cylinder axis direction of the placing core protrude from the bridge portion and are located in the water jacket, and if a drill is inserted into the water jacket and both end faces are cut off, the placing core becomes a hollow member. Therefore, the water jacket communicates with the entire periphery of the cylinder liner. When casting pressure is high,
Since the stake core is hollow, there is a problem in strength. However, the sand is discharged from the water jacket after the end face in the axial direction is cut off using a stake core in which the sand is filled in the hollow space.

[0007]

Problems to be Solved by the Invention Japanese Patent Application Laid-Open No. 9-70645
In the invention described in the publication, since a plate-shaped placement core having a two-part structure is used, a jig is inserted into the division surface of the placement core and the cores are rotated in directions opposite to each other, The core can be removed from the water jacket relatively easily. Further, since the placing core is formed of a solid metal material, the production of the placing core is simple, and the casting core can withstand the casting pressure.

However, the two-part structure makes it difficult to set the core, and the clearance between the core and the mold must be strict. Accuracy is required. In particular, in order to remove the locating core, the halves divided into two parts move into the water jackets on the opposite sides to the bridge portion, so that the width of the water jacket at that location (the width in the cylinder radial direction) ) Must be properly designed as a result, the core cannot be removed from the water jacket. Therefore, high dimensional accuracy is also required for the water jacket forming die. Further, there is a possibility that the molten metal may be inserted into the contact surface between the placing core and the mold, and there is a drawback that the burr needs to be removed from the mold because the burr is formed, resulting in extremely low productivity. In particular, since the dividing surface is located immediately below the cast bridge portion, the operation of removing burrs becomes extremely difficult due to the presence of the bridge portion. Further, since a hole is formed in the bridge portion, the strength of the bridge portion is reduced by that much. in addition,
A special jig that can be inserted into the hole is required.

Next, in the invention described in Japanese Patent Publication No. Hei 7-108449, it is necessary to cut off the end face of the placing core to allow the water jacket to communicate after casting, which increases the number of man-hours and requires skill in cutting. . In addition, since the core is hollow, it is difficult to manufacture the core. Further, when the casting pressure is high, it is necessary to fill the hollow portion of the core with sand or the like, which requires a sand removing operation, which lowers productivity.

In view of the above, the present invention makes it possible to easily set the placement core in the mold, to easily remove the placement core from the water jacket without using any special jig, and to design the die part for the water jacket. Is relatively easy,
It is an object of the present invention to provide a cylinder block manufacturing mold device in which burrs are less generated, burrs generated can be easily removed, a large area of a bridge portion can be ensured, and a mounting core can be easily manufactured.

[0011]

In order to achieve the above object, the present invention provides a water jacket 10 surrounding a plurality of cylinder liners 11 arranged side by side. In order to manufacture an aluminum alloy closed deck type cylinder block 1 provided with a plurality of bridge portions 6 covering the portion, a cylinder block forming die including a water jacket die portion 30 is provided. A plurality of cutouts 31 are formed in the crankcase 30 on the side opposite to the top deck and extend in the axial direction of the cylinder, and the cutouts 30a are formed through the cutouts 31a of the cutouts to form the bridge 6. In the mold apparatus for manufacturing a cylinder block provided with the placing core 20 which is slidably fitted in the portion, the notch 3 Has a substantially square shape, a bottom surface 31c of the notch portion facing the opening 31a of the notch portion forms an inclined surface, and a part of the inclined surface is provided so as to communicate with a top deck side end surface of the die portion 31d. The placement core 20 is a substantially rectangular solid member made of metal, and one of the placement cores 20 is disposed in each of the notches 31.
a and the crankcase-side end surface 20b are formed with draft angles which are inclined in opposite directions in the cylinder axis direction along the circumferential direction of the cylinder, and the inclined surface of the bottom surface 31c of the notch 31 is the same as that of the top deck-side end surface 20a. The present invention provides a mold apparatus for manufacturing a cylinder block, which coincides with a draft angle.

Here, it is preferable that the placing core 20 is made of an aluminum alloy. Alternatively, the placing core is made of iron, and it is preferable that an inner layer made of a mixture of graphite and a water-soluble release agent for die casting and an outer layer made of metal soap are formed on the surface.

Further, the end surface 2 on the top deck side of the placing core 20
It is preferable that a chamfered portion 20e is formed at the corner portion on the top deck end surface side where the distance in the cylinder axial direction between the first end portion 0a and the crankcase side end surface 20b is shortest.

The thickness of the die portion 30 gradually increases toward the adjacent portion of the cylinder.
When 0 is set on the die, the chamfered portion 20e is preferably set on the thinner side of the die.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mold apparatus for manufacturing a cylinder block according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a view of an in-line four-cylinder closed deck type cylinder block 1 as viewed from the top deck side, and FIG. 2 is a partially cutaway perspective view showing a part of a cast cylinder block 1. . This cylinder block 1
Is made of an aluminum alloy, provided with a plurality of cylinder liners 11 juxtaposed for sliding a piston (not shown), and a water jacket 10 surrounding the cylinder liners is formed around the cylinder liners 11. Here, the width of the water jacket 10 in the cylinder radial direction is formed so as to gradually increase toward the direction in which the cylinders are adjacent (w2> w1).

In order to reduce engine vibration and reinforce the top deck surface of the cylinder block 1, a plurality of bridges 6 are provided for connecting the cylinder head mounting frame 7a and the outer end 7b of the cylinder. The cylinder block 1 provided with the plurality of bridge portions 6 covering a part of the upper end opening of the water jacket 10 is generally called a closed deck type cylinder block. In addition, below the bridge part 6 in the water jacket 10, a placement core 20 described below is located. This nakako 2
Zeros are all removed from the water jacket 10 as described below.

A mold apparatus for manufacturing a cylinder block for manufacturing a closed deck type cylinder block 1 will be described with reference to FIGS.

The mold device for manufacturing a cylinder block has a mold for forming a cylinder block provided with a die portion 30 for forming the water jacket 10 and a placing core 20 fitted to the die portion 30 during casting. . The die portion 30 has an opening 31a that opens on the crankcase side (arrow C in FIG. 3), and is formed with a plurality of substantially square notches 31 extending in the axial direction of the cylinder. In the present embodiment, two cylinders are formed symmetrically at positions 90 degrees apart from the adjacent cylinders. Further, an end face 31b of each notch 31 in the axial direction of the cylinder is formed with a groove having a U-shaped cross section.
Bottom surface 31c of notch facing opening 31a of notch 31
Is an inclined surface, and a part of the inclined surface is a communication notch 3 communicating with an end surface (arrow T in FIG. 3) of the die portion on the top deck side.
1d is formed. Note that in FIG.
OB is a wall surface of the die portion 30 for defining the top deck surface and a cylindrical protrusion of a cylinder block forming mold for defining a cylinder bore.

In order to form the bridge portion 6, the placement core 20 is slid into the notch 31 through the opening 31a of each notch. The placement core 20 is a substantially square solid member made of an aluminum alloy, and one of the placement cores 20 is disposed in each of the cutouts 31. The placement core 20 has a top deck side end face 20 a and a crankcase side end face 20 b. Has a draft that is inclined in the direction opposite to the cylinder axial direction along the circumferential direction of the cylinder. Specifically, in FIG. 4, the top deck side end surface 20a and the crankcase side end surface 20b are inclined so that the distance therebetween increases toward the right. The inclination angle of the top deck side end surface 20 a of the placement core 20 is
1c coincides with the inclination angle of the inclined surface. In addition, laying down 20
The end faces 20c and 20d in the cylinder axial direction project in an L-shape in cross section, and are slidably fitted into the groove in the notch 31 in the end face 31b in the axial direction of the cylinder of the cylinder.
Further, as shown in FIG. 3, the thickness of the placing core 20 is formed such that the cylinders gradually increase in the direction in which the cylinders are adjacent to each other (w4> w3).

At the stage where the core 20 is inserted into the notch 31 from the opening 31a of the notch 31 and the top deck side end surface 20a is moved until it contacts the bottom surface 31c of the notch 31, the core 20 is notched. The notch 31 is firmly fitted into the notch 31 such that movement in the cylinder axis direction relative to the portion 31 is prevented. Further, the groove 31a and the projection 20 having a U-shaped cross section
c, 20d, the die portion 30 of the
Relative movement in the cylinder radial direction is also prevented.

When the thickness of the fitting portion of the placing core 20 when the placing core 20 is fitted into the notch portion 31 is compared with the thickness of the fitting portion of the die portion 30, The wall thickness of the die 20 is smaller than that of the die part 30. Therefore, after casting of the cylinder block, the placing core 20 can move in the circumferential direction without interfering with the water jacket wall surface.
When the thickness of the placing core 20 is formed to be thicker than the thickness of the die part 30, the placing core 20 is
This is because it cannot move because it interferes with the wall surface of the cylinder No. 0 and the cast core 20 cannot be removed from the cylinder block after casting.

As shown in FIG. 4, the placement core 20 is substantially square, but the top deck side end face 20a of the placement core 20 is formed.
A chamfered portion 20e is formed at a corner portion on the side of the top deck end surface 20a where the distance between the shaft end and the crankcase side end surface 20b is the shortest in the cylinder axis direction. As described above, the thickness of the die portion 30 gradually increases toward the cylinder adjacent portion, and when the placing core 20 is set in the die portion 30, the chamfered portion 20 e becomes thinner in the die portion 20. Set on the thin side.

Next, a process of manufacturing a cylinder block using the above-described mold apparatus for manufacturing a cylinder block will be described.

Since the holder 20 is a solid aluminum alloy material and has a simple outer shape, it can be mass-produced by die casting or the like. The placement core 20 is inserted into the notch 31 from the opening 31a of the notch 31, and the top deck side end surface 20a is brought into contact with the bottom surface 31c of the notch 31. At this time
As shown in FIG. 3, the sliding surface between the 0 and the notch 31 has a “<” shape, so that the placing core 20 can be set accurately. The combination of the die part 30 and the placing core 20 provides a water jacket equivalent part. Note that if graphite is applied to the surface of the placing core 20 before setting the placing core 20, separation from the cast product becomes easy.

When the aluminum alloy melt is filled after the cylinder liner 11 is inserted into the cylindrical projection 30B of the cylinder block forming mold, the cylinder liner 11
Is cast with molten metal and water jacket 1
The cylinder block 1 in which 0 is formed is formed. At this time, the wall 30A of the die part 30 and the communication notch 31d are formed.
Then, the space defined by the top deck side end surface 20a of the placing core 30 is also filled with the aluminum alloy melt, and the bridge portion 6 is formed at a part of the opening of the water jacket 10.

When the molten metal is filled, only one placing core 20 is arranged in the cutout 31, so that the number of burrs is small. Further, since the placing core 20 is formed of a solid member, there is no possibility of deformation even when a high casting pressure is applied.
Also, since the placing core 20 is made of an aluminum alloy, even if there is some clearance between the mold and the placing core 20, the aluminum alloy has a higher thermal expansion coefficient than iron, so The clearance becomes small due to the thermal expansion of the child 20. Therefore, the volume of the burr can be reduced.
Furthermore, since the aluminum alloy has a high thermal conductivity, it has a high ability to deprive the heat of the molten metal, and the molten metal that has entered the clearance portion is rapidly cooled and solidified by the placing core 20, thereby preventing the flash from deeply penetrating. be able to.

After the molten metal has solidified, the cylinder block forming mold is opened. At this time, since the placement core 20 interferes with the bridge 6, the notch 31 of the die part 30 slides with respect to the placement core 20, and the die part 30 separates from the placement core 20 and is placed. The child 20 remains in the cylinder block 1.

Next, in order to remove the placing core 20, a hammer or the like is inserted into the water jacket and the chamfered portion 20e is hit in the X1 direction, and the placing core 20 moves in the X2 direction in FIG. Can be. At this time, the placement core 20 can move smoothly with respect to the solidified bridge portion 6 and the bottom surface of the water jacket due to the draft angles 20a and 20b having the above-described configuration. Further, as described above, the configuration is such that the thickness of the placement core 20 is gradually increased in the moving direction, and the die part 30 is larger than the thickness of the placement core 20.
Is thickened, so that the placing core 20 does not significantly interfere with the wall surface of the water jacket 10 when the placing core 20 moves. Furthermore, since the core 20 is made of the same material as the molten metal, even if burrs are formed,
Easily, and the burr can be removed together with the placement core when the placement core 20 is taken out, and does not remain in the mold. Therefore, it is possible to easily set the placement core at the next shot.

Next, a mold apparatus for manufacturing a cylinder block according to a second embodiment of the present invention will be described. First
In the embodiment, since the core is made of an aluminum alloy, the weight of the core is light, so that it is easy to insert the core 20 into the cutout portion 31. Further, the core itself is die-cast and mass-produced. It has various advantages, such as being able to be produced and being able to be dissolved together with the casting when the casting cannot be separated from the core, but on the other hand, it is softer than iron, so the notch after casting If the hitting surface is extremely small when separating the placing core from the mold, there is a problem that it is simply deformed into a concave shape and it is difficult to separate from the notch, and a mold for placing core casting Is necessary separately.

In the second embodiment, the core is made of iron for the purpose of handling small lot products. The shapes of the core and the die are the same as in the first embodiment. If the cast core is made of iron, so that the cast product cannot be separated from the cast core, after dissolving and disposing the cast core together with the cast product, remove the cast core from the molten aluminum,
The trouble is required. In order to avoid this trouble, at the time of casting, it is necessary to provide the core with extremely high releasability as compared with the aluminum core-made core. Also, since the iron-made core is used repeatedly, aluminum adheres to the fitting part with the die part,
It becomes difficult to insert the locator into the die. Therefore, it is necessary to prevent adhesion of aluminum to the fitting portion between the placing core and the die.

First, before setting the iron core in the die, the core is dipped in a mixture of graphite and a water-soluble release agent for die casting. Thereby, the detachability and cooling property of the placed core are improved. Next, a metallic soap is applied to the dipped core. Examples of the metal soap include zinc stearate, calcium stearate, and aluminum stearate. Thus, it is possible to prevent aluminum from being attached to the fitting portion of the placing core with the die. The pre-treated core is inserted into the die portion, and the filling of the aluminum alloy melt, the mold opening after the solidification of the molten metal, and the removal of the core are performed as in the first embodiment.

The present invention is not limited to the embodiments described above, and various modifications are possible. For example, according to the present embodiment, as shown in FIG. 3, a substantially U-shaped groove is formed in the axial end face 31 b of the notch 31 extending in the axial direction of the cylinder liner. The groove is not limited to a letter shape, but may be an arc-shaped groove or a convex shape.

Further, as shown in FIG.
A chamfered portion 20e is formed at a predetermined corner of
If it can be moved by hitting the placing core through the space of the water jacket 10, the chamfered portion 20e
May not be provided.

In the cylinder block 1 shown in FIG. 1, the bridge portions 6 may be formed at both ends of the cylinder block. The cylinder block is not limited to the in-line four-cylinder type. Of course, it can be applied to a type engine.

[0036]

According to the die apparatus for manufacturing a cylinder block according to the present invention, a single placement core is arranged in each notch instead of a two-piece placement core. It is easy to set the mold. Further, since it is not necessary to form a hole in the bridge portion, the area of the bridge portion is increased, and the mechanical strength can be increased. Further, there is no need to prepare a special jig for inserting the hole into the hole. In addition, since the placement core is single for each notch, when removing the placement core from the water jacket, it is sufficient to move the placement core in the direction of the adjacent cylinder where the water jacket gradually becomes wider. In other words, the design of the water jacket forming die can be performed more easily. JP-A-9-706
This is because, in the plate-shaped core having a two-part structure described in Japanese Patent Publication No. 45-45, since the cores move in directions opposite to each other, the space of the water jacket must be taken into account.

Further, since there is no divided surface, the number of burrs is reduced, and burrs are not generated on the divided surface, so that the operation of removing burrs becomes easier.

Further, since the placing core is formed of a solid member, it is easier to manufacture as compared with the case where the placing core is hollow, and there is no possibility of deformation even when a high casting pressure is applied.

According to the mold apparatus for manufacturing a cylinder block according to the second aspect, since the placing core is formed of an aluminum alloy, even if there is some clearance between the mold and the placing core, the aluminum alloy is not removed. Since the thermal expansion coefficient is higher than that of iron, the clearance becomes smaller due to the thermal expansion of the core, so that the volume of the burr can be reduced. Furthermore, since the aluminum alloy has a high thermal conductivity, it has a high ability to deprive the heat of the molten metal, and the molten metal that has entered the clearance portion is rapidly cooled by the placing core, so that it is possible to prevent burrs from penetrating deeply.

In addition, since the material of the core is the same as the molten metal, even if the burr is formed, the burr easily adheres to the core and the burr is removed together with the core when the core is removed. Done and do not remain in the mold. Therefore, not only is it easy to set the placement core at the next shot, but also at the time of throwing out the cylinder block, the casting can be dissolved and disposed as it is while the placement core remains in the water jacket. In addition, since the placement core itself can be manufactured by die casting, mass production becomes possible, and a new placement core can be used for each shot.

According to the third aspect of the present invention, since the chamfered portion is formed on the placing core, the hammer or the like is used for removing the placing core from the water jacket. It can be easily hit with a tool, and the extraction work becomes easy. Here, the chamfered portion was provided at the corner portion on the top deck end surface side where the distance in the cylinder axis direction between the top deck side end surface of the placing core and the crankcase side end surface was the shortest, so the beveled portion was hit with a tool. Sometimes, in the water jacket, the placement core can move in a direction in which the distance between the top deck side end face of the placement core and the crankcase side end face gradually increases, and it is easier to remove the placement core. Become.

According to the cylinder block manufacturing die apparatus of the fourth aspect, since the width of the water jacket gradually increases in the moving direction of the placing core during the work of removing the placing core, The core does not interfere with the wall surface of the water jacket, and the removal operation is further simplified.

According to the mold apparatus for manufacturing a cylinder block according to the fifth aspect, since the placing core is made of iron, it is possible to cope with small lot products, and it is easy to take out the placing core. Since the first layer and the second layer are formed, the releasability from the aluminum alloy and the anti-adhesion property are improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a closed deck type cylinder block manufactured by a mold apparatus for manufacturing a cylinder block according to an embodiment of the present invention.

FIG. 2 is a partially cut-away portion showing a closed-deck type cylinder block manufactured by a mold apparatus for manufacturing a cylinder block according to an embodiment of the present invention, showing a state before removal of a core after casting. Perspective view.

FIG. 3 is a perspective view showing a main part of a mold apparatus for manufacturing a cylinder block according to an embodiment of the present invention.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 6 Bridge part 10 Water jacket 11 Cylinder liner 20 Placing core 20a Top deck side end face 20b Crank case side end face 30 Die part 31 Notch part 31a Notch opening 31c Notch bottom 31d Communication notch

Claims (5)

[Claims] 1. A closed deck made of an aluminum alloy in which a water jacket surrounding a plurality of cylinder liners arranged side by side is formed, and a plurality of bridge portions covering a part of an upper end opening of the water jacket are provided on a top deck. In order to manufacture a cylinder block of the type, a mold for forming a cylinder block provided with a die portion for a water jacket is provided, and the die portion is opened on the crankcase side opposite to the top deck and extends in the axial direction of the cylinder. A plurality of extending notches are formed, and a cylinder block manufacturing mold apparatus provided with a placement core slidably fitted into the notch from an opening of each of the notches to form a bridge. The notch has a substantially quadrangular shape, and the bottom of the notch facing the opening of the notch forms an inclined surface, and the notch has one side. Is provided in communication with the top deck side end surface of the die part, and the placing core is a substantially rectangular solid member made of metal, and one is disposed in each notch, and the top deck of the placing core is provided. The side end face and the crankcase side end face are formed with a slope that is inclined in the direction opposite to each other in the cylinder axis direction along the circumferential direction of the cylinder, and the slope of the bottom surface of the cutout is formed with the slope of the top deck side end face. A mold apparatus for manufacturing a cylinder block, which is identical. 2. The die apparatus for manufacturing a cylinder block according to claim 1, wherein said placing core is made of an aluminum alloy. 3. A chamfered portion is formed at a corner on the side of the top deck where the distance between the top deck side end of the placing core and the crankcase side is shortest in the cylinder axis direction. The mold device for manufacturing a cylinder block according to claim 1. 4. The die portion has a thickness gradually increasing toward the adjacent portion of the cylinder, and when the placing core is set on the die portion, the chamfered portion of the die portion is formed on the die portion. The mold apparatus for manufacturing a cylinder block according to claim 3, wherein the mold apparatus is set on a thin side. 5. The method according to claim 1, wherein the placing core is made of iron, and has on its surface an inner layer made of a mixture of graphite and a water-soluble release agent for die casting, and an outer layer made of metal soap. Item 7. A mold device for manufacturing a cylinder block according to Item 1.