JPH08294764A - Die for producing cylinder block - Google Patents

Abstract

PURPOSE: To produce a closed deck and wet liner type cylinder block by utilizing the high productivity as the merit of a die casting method. CONSTITUTION: A set of movable (retractable) cores 17 is arranged in a fixed core 16 provided in a movable core 15 in a die for producing the cylinder block. In a prescribed projecting position of the movable cores 17, a large diameter circular columnar part 500 is formed by engaging the movable cores 17 with a placed core before die-clamping. This large diameter circular columnar part 500 is used to form a water jacket part of the cylinder block. After solidifying the molten metal ejected into the inner part of the clamped die, the large diameter circular columnar part 500 can be separated into the movable cores 17 and the placed core. Then, the die is opened without interfering with an undercut part by putting the movable cores 17 into the inner part of the fixed core 16. After opening the die, the placed core is also independently taken off without interfering with the undercut part. By this method, the forming cycle is shortened and the producing cost is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die structure for forming a cylinder block of a die cast closed deck engine, and more particularly to a die structure for forming a water jacket portion of the cylinder block. Is.

[0002]

2. Description of the Related Art Generally, a cylinder block of an engine made of an aluminum alloy incorporates a cylinder liner made of a thin wear-resistant material, and an outer peripheral portion of a cylinder bore in which a piston is fitted is formed in the cylinder liner. .

In this type of cylinder block, for example,
An open deck type, such as a cylinder block 1 shown in FIG. 17, having a structure in which a water jacket 3 formed on an outer peripheral portion of a cylinder liner 2 for circulating cooling water is opened at a cylinder head mounting surface 4, As in the cylinder block 5 shown in FIG. 18, the water jacket 7 formed on the outer peripheral portion of the cylinder liner 6 is closed by the cylinder head mounting surface 8 and the cooling water passage 9 communicating with the water jacket 7 is connected to the cylinder head mounting surface 8. There is a closed deck type with a structure provided with.

The open-deck type cylinder block 1 as shown in FIG. 17 can be easily molded by a die casting method when cast and molded from an aluminum alloy or the like, but the cylinder head mounting surface 4 is open. ,
It has the drawbacks of low rigidity and easy generation of vibration and noise.

On the other hand, in the closed-deck type cylinder block as shown in FIG. 18, since the cylinder head mounting surface 8 is closed, the rigidity is high and vibration and noise are less likely to occur. The advantage is that Further, like the cylinder block 10 shown in FIG.
The closed deck wet liner type in which the water jacket 12 is formed on the outer peripheral portion of the cylinder liner 11 is excellent in cooling efficiency because the cooling water in the water jacket 12 directly contacts the cylinder liner 11. In addition,
19, those parts that are the same as those corresponding parts in FIG. 18 are designated by the same reference numerals.

By the way, the closed deck wet liner type cylinder block 10 is difficult to form by the die casting method because the water jacket 12 forms an undercut portion due to its structure, and in general, a collapsible core is used. Although it is molded by the gravity casting method or the low pressure casting method, there is a problem that the core is complicated to manufacture and take out after molding, and the productivity is low.

Therefore, various methods for manufacturing a closed deck wet liner type cylinder block by using a die casting method have been conventionally proposed in order to improve productivity. For example, a method of forming a water jacket using a split type movable core (see Japanese Patent Publication Nos. 2-53623 and 2-53624), a water jacket is formed similarly to the open deck type, and then a cylinder head is formed. A method of closing a part of the opening of the mounting surface (Japanese Patent Laid-Open No. 1-10
No. 0352, JP-A-1-147145, Japanese Patent Publication No. 2-1
No. 1735), a method of casting a cylinder liner having a water jacket in advance (Japanese Patent Laid-Open No. 62-113).
No. 845, Japanese Utility Model Laid-Open No. 5-78950), and a small diameter portion of the stepped bore formed in the cylinder block, a cylinder liner having a flange portion on the outside of one end is press-fitted to obtain a large diameter Part and the side wall and the flange part of the cylinder liner to form a water jacket (JP-A-60-135650, Japanese Utility Model Publication No. 1-104).
No. 27) is proposed.

[0008]

However, the above-mentioned conventional method of manufacturing a cylinder block has the following problems. That is, in the method (1), the structure of the mold is complicated and the movable core is difficult to have sufficient strength, so that the mold cost becomes high and the mold life is short. In the above method, the step of closing a part of the opening is complicated, and improvement in productivity cannot be expected so much. In the method (1), the cylinder liner has a complicated shape and is difficult to manufacture. Therefore, improvement in productivity cannot be expected so much. In this method, it is difficult to firmly connect the cylinder block main body and the cylinder liner, and the rigidity of the cylinder block decreases. in this way,
The manufacturing method of the cylinder block shown above to
It cannot be said that any of them have been sufficiently satisfactory.

The present invention has been made in view of the above problems. An object of the present invention is to provide a mold having a structure that is easy to handle and can be used repeatedly during die casting of a cylinder block. It is possible to simultaneously form an undercut portion for forming a water jacket portion, and to easily provide a closed deck wet liner type cylinder block without impairing the high productivity of the die casting method. .

[0010]

Means for Solving the Problems According to the present invention for solving the above-mentioned problems, there is provided a mold for producing a cylinder block having a fixed mold, a side mold and a movable mold, The movable mold has a cylindrical fixed core for forming the outer peripheral portion of the cylinder bore, and a set of movable cores having a predetermined height and retractable at predetermined positions facing each other on the side walls of the fixed core. And a stationary core that engages with the movable core and forms a large-diameter cylindrical portion concentric with the fixed core at a predetermined protruding position of the movable core.

In the present invention, the placing core is substantially in the same height as the movable core, and has a substantially arched shape having an inner wall that can be closely attached to the side wall of the fixed core. It is desirable that both ends of the movable core have a shape capable of being in close contact with each other.

Further, a positioning shaft protruding in the height direction is formed on the inner wall of the placing core so as to slidably engage with a guide groove provided in the stationary core, and a base end portion of the positioning shaft is formed. Further, it is possible to form an engaging claw with the fixed core.

[0013]

The movable mold has a cylindrical fixed core for forming an outer peripheral portion of the cylinder bore, and a set of a predetermined height is provided at a predetermined position facing the side wall of the fixed core so as to be retractable. A movable core is provided, and at a predetermined projecting position of the movable core, there is a stationary core that engages with the movable core to form a large-diameter cylindrical portion concentric with the fixed core, The large diameter cylindrical portion is used to form the water jacket portion of the cylinder block. Moreover, after the molten metal injected into the mold that has been clamped is solidified, the large-diameter cylindrical portion is separated into the movable core and the placing core, and the movable core is stored inside the fixed core. The mold is opened without interfering with the undercut part. After opening the mold, remove the placing core independently without interfering with the undercut part.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. In the figure, the same or corresponding parts as those of the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

First, the main members of the mold for manufacturing a cylinder block according to the present invention will be described. As shown in FIG. 1, the mold according to the present invention includes a fixed mold 13, a side mold 14, and a movable mold 15, and each mold is clamped to form a closed mold. The cylinder block is formed by filling the space with molten aluminum and solidifying it.

As shown in FIGS. 1 and 2, the movable mold 15
A cylindrical fixed core 16 for forming an outer peripheral portion of the cylinder bore is provided in the. The fixed core 16 is fixed to the movable mold 15.When the movable mold 15 moves for mold clamping or mold opening, the fixed core 16 also moves with the movable mold 15. To do. The side wall 161 of the stationary core 16 has 1
A pair of movable cores 17 are provided at opposite positions. Also,
The movable core 17 has a predetermined height H (that is, the height H of the undercut portion formed inside the cylinder block),
"Storing position" that is stored inside the side wall 161 of the stationary core 16
(See FIG. 6) and a “projection position” at which a predetermined amount T (that is, the thickness T of the undercut portion formed inside the cylinder block) is projected to the outside of the side wall of the fixed core 16. It is freely retractable from the side wall 161 of the stationary core 16. Further, the movable cores 17, 17 facing each other are adapted to appear and disappear together. That is, FIG. 1 and FIG. 2 show the state at the “protruding position”.

The movable core 17 has a small diameter portion 171 and a large diameter portion 172 on its outer wall. The small diameter portion 171 is formed to have the same radius as the side wall 161 of the stationary core 16 when in the “protruding position”. Further, at the same position, the radius of the large diameter portion 172 has a radius larger than the radius of the small diameter portion 171 by a predetermined amount T. Therefore, as shown in FIGS. 2 and 7, when the movable core 17 is in the “protruding position”, the small diameter portion 171 is
Is flush with the side wall of the stationary core 16 and
To form. In addition, the large diameter portion 172 is provided with a storage core 18 described later.
A large-diameter cylindrical portion 500 is formed which has the same surface as that of and is concentric with the fixed core 16.

As shown in FIG. 1, the "protruding position" of the movable core 17 is such that a movable space S of the movable core 17 is formed between the movable mold 15 and the fixed core 16, and the small diameter portion is formed. 171 is a movable mold 15
It is determined by abutting on the end surface 15S of.

Further, both ends 173 of the movable core 17 are formed in a plane shape parallel to the direction in which the movable core is projected and retracted as shown in FIG. Sliding surface
You will be guided to 162.

The storage core 18 will now be described. The stationary core 18 is used integrally with the fixed core 16, and has a substantially arched shape as shown in FIGS. 2 and 3. The inner wall 181 of the stationary core 18 has substantially the same radius as that of the fixed core 16, and can be closely attached to the side wall 161 of the fixed core 16. Further, the outer wall 182 of the storage core 18 is flush with the large diameter portion 172 of the movable core 17 as described above, and has a large diameter cylindrical portion 500.
Large diameter part of the movable core 17 so that it can be formed 1
It has the same radius as 72.

Both ends 183 of the placing core 18 are flat as if cut along the same cutting plane, and when attached to the fixed core 16, they are flush with the sliding surface 162 of the fixed core 16. None, slidingly guide both side surfaces 173 of the movable core 17.

A positioning shaft 184 protruding in the height direction is provided on the inner wall 181 of the placing core 18. Positioning axis
184 is a guide groove 163 provided on the side wall 161 of the stationary core 16.
(See FIGS. 5 and 6) slidably engages. Further, as shown in FIG. 4, an engaging claw is provided on the base end of the positioning shaft 184.
It is also possible to form 185 and fix the engaging claw 185 to the base end portion of the guide groove 163.

Further, as shown in FIG. 8, an engaging claw 186 and an engaging claw 174 are formed on the both ends 183 of the placing core 18 and the both ends 173 of the movable core 17 so as to be in close contact with each other. , Movable core 17
It is also possible for them to be sufficiently fixed to each other when they project into the "projection position".

By the way, all the main members of the die for manufacturing the cylinder block described above are made of a general die steel material.

The procedure for die casting a cylinder block using the die for manufacturing a cylinder block of the present invention will be described below.

FIG. 5 shows a fixed core before the fixed mold 13, the side mold 14, and the movable mold 15 shown in FIG. 1 are clamped.
16 states are shown. At this time, the movable core 17 is in the "storage position" as shown in FIG. First of all, fixed core
The guide groove 163 of 16 and the positioning shaft 184 of the stationary core 18 are engaged with each other so that the inner wall 181 of the stationary core 18 is attached to the side wall 161 of the stationary core 16.
In close contact with. This work can be unmanned using a work robot or the like.

Next, as shown in FIGS. 2 and 7, the movable core 17 is projected to the "projection position", and the engaging claws 174,
Movable core 17 and stationary core due to engagement of 186 (see FIG. 8)
18 is fixed, and the large diameter cylindrical portion 500 is formed by the large diameter portion 172 of the movable core 17 and the outer wall 182 of the stationary core 18. At the same time, the small diameter portion 171 of the movable core 17 and the side wall 161 of the fixed core 16 form a small diameter cylindrical portion 600. In this state, the fixed mold 13, the side mold 14, and the movable mold 15 are each clamped, and the mold is shown in FIG.

As is apparent from FIG. 1, an undercut portion for forming a water jacket is formed in the closed space formed by each mold by the large-diameter column portion 500 sandwiched by the small-diameter column portion 600. Has been done. FIG. 9 shows a state where the molten metal is filled in the mold. A cylinder block 19 '(semi-finished product) is formed in the mold by sufficiently solidifying the filled molten metal.

Next, as shown in FIG. 9, the movable core 17 is immersed in the "storage position". At this time, as shown in FIG. 6, the movable core 17 is housed inside the side wall 161 of the fixed core 16. At the same time, the engaging claws 174 and 186 shown in FIG. 8 are disengaged, so that the movable core 17 and the stationary core 18 are unlocked from each other. In this state, the movable mold 15 is opened rightward in FIG. 9, and the fixed core 16 is pulled out from the opening end 201 of the cylinder bore outer peripheral portion 20. Then fixed core 16 and standing core
18 is separated (state shown in FIG. 5), and only the placing core 18 is left inside the undercut portion 21 of the cylinder block 19 '. Further, the fixed core 16 in which the movable core 17 is housed and has no protrusion can be pulled out from the opening end 201 of the cylinder bore outer peripheral portion 20 without interfering with any part of the cylinder block 19 ′.

Following the opening of the movable mold 15, the side mold 14
Also, the mold is opened and the cylinder block 19 'is released. And
The storage core 18 left behind in the undercut portion 21 is taken out from the open end 201 of the cylinder bore outer peripheral portion 20. Removing the cylinder block 19 'from the mold and placing core 18
The work of taking out from the undercut portion 20 can be unmanned by a robot or the like.

By the procedure described above, the cylinder block 19 'having the undercut portion 21 on the cylinder bore outer peripheral portion 20 as shown in FIG. 10 can be die cast.

Next, as shown in FIG. 11, the outer peripheral portion 20 of the cylinder bore is machined and dimensioned for fitting the cylinder liner 22 later. And the cylinder liner 22
The cylinder block 19 having the water jacket 23 as shown in FIG. 12 is completed by press-fitting.

Although the above description has been made with the manufacturing process of the cylinder block of the single cylinder engine in mind, the mold structure according to the present invention is easily applied to the manufacturing of the cylinder block of the multi-cylinder engine. can do. In this case, a water channel between the cylinders is formed by using a core having a shape that connects adjacent cylinders.

The effects obtained by using this embodiment will be described below. The movable core 17 is freely retractable from the fixed core 16 provided in the movable mold 15. When the movable core 17 is projected to the "protruding position", the movable core 18 is moved to the movable core. The large diameter cylindrical portion 500 can be formed by being integrated with 17. After forming this large-diameter cylindrical portion 500, the fixed mold, the side mold, and the movable mold are clamped, and a closed space having the shape of a cylinder block 19 '(semi-finished product) is formed inside the mold. To form. In the closed space, an undercut portion that will later become a water jacket is formed by the large-diameter columnar portion 500.

The molten metal is filled into the mold which has been clamped,
After the solidification, the movable core 17 is retracted to the "retracted position" so that only the placing core 18 is moved to the cylinder block 1.
The fixed core 16 can be pulled out from the cylinder block 19 ′ along with the mold opening of the movable mold 15 by leaving it in the undercut portion 21 of 9 ′. Then, by releasing the cylinder block 19 'and taking out the placement core 18 left in the undercut portion 21, the undercut portion 21 for forming the water jacket portion is formed when die casting the cylinder block. It can be formed at the same time.

Since all the main members of the mold are made of general mold steel, they are easy to handle and can be used repeatedly. Therefore, the die cost can be kept low. Further, the procedure of die casting the cylinder block 19 'can be entirely automated, and the molding cycle can be shortened. Therefore,
Production costs can also be reduced.

By the way, as a structure for driving the movable core 17, it is also possible to use the type described below. This modified embodiment is shown in FIGS. 14 to 16. Further, the same parts as or corresponding parts to those of the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 13 shows a vertical cross-sectional view of the fixed core 16 and the movable core 17 in the "storage position" of the modified embodiment. The movable cores 17 arranged to face each other have an inner wall 175 inclined so that the thickness thereof increases toward the tip, and the tip of the inner wall 175 is fixed by a biasing means such as a spring (not shown).
It abuts at the center of 16. Further, the fixed core 16 has a hollow portion 164, and the driving member 24 slidably guided in the hollow portion 164.
At the tip of the, an inclined surface that slidably contacts the inner wall 175 of the movable core 17
Forming 241. In the "storage position" above,
As shown in FIG. 14, the movable core 17 is housed inside the side wall 161 of the fixed core 16.

FIG. 15 shows a vertical sectional view at the "protruding position". By moving the drive member 24 forward (to the left in the drawing), the inclined surface 241 pushes the inner wall 175 of the movable core 17 in the radial direction of the fixed core 16. Then, the driving member 24
When the movable core 17 reaches the movement limit position, the movable core 17 can obtain a predetermined protrusion amount T. FIG. 16 shows a state where the storage core 18 is integrated to form the large-diameter columnar portion 500. Further, by retracting the driving member 24, it can be returned to the "storage position" as shown in FIG. 13 again by the biasing means.

Even when the mold structure according to this modified embodiment is used, the procedure for manufacturing the cylinder block is the same as that of the above-mentioned embodiment, and the detailed description thereof is omitted here.

As the operation and effect obtained by this embodiment, since the movable core 17 can be retracted and retracted by moving the driving member 24 back and forth, the structure is simple and it is hard to break.
It can be a low cost mold. In addition, it is possible to obtain the same effects as those of the above-described embodiment.

[0042]

Since the present invention is constructed as described above, the following effects can be obtained. The movable mold has a cylindrical fixed core for forming the outer peripheral portion of the cylinder bore, and a set of movable cores having a predetermined height and retractable at predetermined positions on the side walls of the fixed core. A core is provided, and at a predetermined projecting position of the movable core, it has a stationary core that engages with the movable core to form a large-diameter columnar portion concentric with the fixed core, The undercut portion is formed inside the cylinder block by forming the large-diameter cylindrical portion before clamping. Moreover, after the molten metal injected into the mold that has been clamped is solidified, the large-diameter cylindrical portion is separated into the movable core and the placing core, and the movable core is stored inside the fixed core. The mold can be opened without interfering with the undercut portion.

Further, after the mold is opened, the placing core can be independently removed without interfering with the undercut portion. Therefore, when die casting the cylinder block, the undercut portion for forming the water jacket portion is simultaneously formed. Can be formed. Since all the main members of the mold are made of general mold steel, they are easy to handle and can be used repeatedly. Therefore, the die cost can be kept low. Further, the procedure of die casting the cylinder block can be entirely automated, and the molding cycle can be shortened. Therefore, the production cost can be reduced.

The cylinder liner is press-fitted into the outer peripheral portion of the cylinder bore of the cylinder block formed by the above method, whereby the closed deck wet liner type cylinder block is completed. With the above configuration, while fully exerting high productivity by die casting,
A closed deck wet liner type cylinder block can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a mold clamping state, which is a first stage of a cylinder block manufacturing process using a cylinder block manufacturing mold according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view taken along the line AA of FIG. 1 and is a schematic view showing a “projection position” of a movable core.

3 is a three-dimensional perspective view of a placing core which is a constituent member of the mold for manufacturing the cylinder block shown in FIG.

4 is a vertical cross-sectional view taken along the line BB of FIG. 3, which is a schematic view showing a state in which it is attached to a stationary core.

5 is a perspective view showing a state where the stationary core and the placing core are separated from each other in the mold for manufacturing the cylinder block shown in FIG. 1. FIG.

6 is a cross-sectional view taken along the line C-C in FIG. 5, which is a schematic view showing a "retracted position" of the movable core.

7] The fixed core and the stationary core shown in FIG. 5 are integrated,
It is a perspective view which shows the state which formed the large diameter cylinder part.

FIG. 8 is an enlarged view of a portion D of FIG.

FIG. 9 is a schematic view showing a second stage of the manufacturing process of the cylinder block.

FIG. 10 is a schematic diagram showing a third stage of the manufacturing process of the cylinder block.

FIG. 11 is a schematic diagram showing a fourth stage of the manufacturing process of the cylinder block.

FIG. 12 is a schematic view showing the final stage of the manufacturing process of the cylinder block.

FIG. 13 is a view showing a mold structure according to a modified example of the present invention, and is a schematic cross-sectional view showing a “retracted position” of the movable core.

14 is a vertical cross-sectional view taken along the line EE of FIG.

FIG. 15 is a view showing a mold structure according to a modified example of the present invention, and is a schematic sectional view showing a “projection position” of the movable core.

16 is a vertical cross-sectional view taken along the line FF of FIG.

FIG. 17 is a schematic diagram showing a conventional open deck type cylinder block.

FIG. 18 is a schematic diagram showing a conventional closed deck cylinder block.

FIG. 19 is a schematic diagram showing a conventional closed deck wet liner type cylinder block.

[Explanation of symbols] 13 Fixed mold 14 Side mold 15 Movable mold 16 Fixed core 161 Side wall 163 Guide groove 17 Movable core 173 Both ends 18 Placement core 181 Inner wall 183 Both ends 184 Positioning shaft 185 Engaging claw 19 Cylinder block 19 'Cylinder block (semi-finished product) 20 Cylinder bore outer circumference 500 Large diameter cylinder

Claims (3)

[Claims] 1. A mold for manufacturing a cylinder block having a fixed mold, a side mold and a movable mold, wherein the movable mold has a cylindrical fixed core for forming an outer peripheral portion of a cylinder bore. And a pair of movable cores having a predetermined height and retractable at a predetermined position facing the side wall of the fixed core, and the movable core is movable at a predetermined protruding position of the movable core. A mold for manufacturing a cylinder block, comprising a stationary core that engages with a core and forms a large-diameter cylindrical portion concentric with the fixed core. 2. The placing core is substantially in the same height as the movable core and has a substantially arched shape having an inner wall that can be in close contact with the side wall of the stationary core, and the movable core and the both end portions of the placing core are movable. The mold for manufacturing a cylinder block according to claim 1, wherein both ends of the core have shapes that can be in close contact with each other. 3. A positioning shaft protruding in the height direction is formed on an inner wall of the placing core so as to slidably engage with a guide groove provided in the stationary core, and a base end portion of the positioning shaft is formed. The mold for manufacturing a cylinder block according to claim 1, wherein an engaging claw that engages with the fixed core is formed in the mold.