JPH0616934B2 - Casting method for fiber reinforced cylinder block material - Google Patents

Description

Detailed Description of the Invention A. Object of the Invention (1) Field of Industrial Application The present invention relates to a method for casting a fiber-reinforced cylinder block material in which the circumference of a cylinder bore is reinforced with a fiber molding.

(2) Conventional technology Conventionally, when casting this type of cylinder block material,
A cylindrical fiber molded body is attached to the outer peripheral surface of the thin-ring bore molding core in which the axis is arranged horizontally, and then in a cylinder block material molding cavity that surrounds the fiber molded body,
A method is used in which the molten metal is injected from one end side of the fiber molded body, and then the molten metal is pressurized and completely solidified under the pressure.

(3) Problems to be Solved by the Invention However, according to the above-mentioned method, the flow of the molten metal becomes an axial flow from one end of the fiber molded body to the other end, and the molten metal easily entrains gas, and the cylinder block The gas is likely to be confined in a portion of the material corresponding to the other end of the fiber molded body. As a result, there is a problem that the cylinder block material has cavities.

It is an object of the present invention to provide the casting method that can solve the above problems.

B. Structure of the Invention (1) Means for Solving the Problems The present invention is to insert a cylinder bore molding insert having cylinder shafts arranged in the vertical direction when casting a cylinder block material reinforced around a cylinder bore with a fiber molding. A step of mounting a cylindrical fiber molding preheated to 200 ° C. or more on the outer peripheral surface of the cylinder; and a gas vent hole and an opening degree in the upper portion of the cylinder block material molding cavity surrounding the fiber molding,
A step of injecting a molten metal into the cavity from the lower portion of the cavity; a step of closing the gas vent hole, pressurizing the molten metal, and safely solidifying under the pressure;

(2) At the same time as pouring molten metal into the working cavity from the bottom of it,
Since the inside of the cavity is degassed through the opening of the gas vent hole whose opening is narrowed, a back pressure is generated in the cavity due to the throttling effect of the opening, and the back pressure is evenly applied to the entire molten metal surface. As a result, the surface of the molten metal is suppressed from waviness and rises substantially horizontally, which prevents the inclusion of debris in the molten metal, and also allows efficient degassing.

Further, since the fiber molded body is preheated to 200 ° C. or higher, the temperature of the molten metal around the fiber molded body is kept warm, and thus the molten metal is prevented from adhering to the fiber molded body.

Furthermore, since the molten metal is pressurized and completely solidified under the pressure, the molten metal having a high temperature around the fiber molded body is efficiently and surely filled in the fiber molded body in the process of increasing the pressure of the molten metal,
Further, the metal structure of the matrix is densified and its strength is improved.

However, if the preheating temperature of the fiber molded body is lower than 200 ° C,
The molten metal is deprived of the hot fiber molding and adheres to the fiber molding, impairing the filling property of the molten metal.

(3) Examples FIGS. 1 to 3 show a fiber-reinforced aluminum alloy Siamese type cylinder block S made of the material obtained by the present invention. The cylinder blocks S are plural in series, and four in the illustrated example. more configuration and the cylinder barrel 1 ₁ to 1 ₄ Siamese cylinder barrel 1 composed by combining each other, an outer wall portion 2 surrounding the Siamese cylinder barrel 1, a crankcase 3 provided continuously to the lower edge of the outer wall 2 To be done. A cylindrical fiber molded body F is embedded around the cylinder bore ₄ in each of the cylinder barrels 1 ₁ to 14, and the fiber molded body F is reinforced around the cylinder bore 4.

A water jacket 6 facing the outer circumference of the Siamese cylinder barrel 1 is formed between the Siamese cylinder barrel 1 and the outer wall portion 2. At the cylinder head side end of the water jacket 6, the Siamese cylinder barrel 1 and the outer wall 2
The spaces are partially connected by a plurality of reinforcing deck parts 8, and the adjacent reinforcing deck parts 8 function as communication ports 7 to the cylinder head side. As a result, the cylinder block S is constructed as a closed deck type.

5 to 8 show the cylinder block material S shown in FIG.
1 shows a casting apparatus used in the present invention and in order to cast m, the apparatus includes a mold M, which is movable up and down, and is disposed below the upper mold 9. In FIGS. 5 and 6, the left and right halves are divided into the first and second side molds 10 ₁ and 10 ₁ .
₂ and FIG. 7, the left and right parts are divided into third and fourth parts.
It is composed of side molds 10 ₃ and 10 ₄ and a lower mold 11 on which the side molds 10 ₁ to 10 ₄ are slidably mounted.

On the lower surface of the upper mold 9, a mold clamping recess 12 that cooperates with the upper half of each of the side molds 10 ₁ to 10 ₄ to define a first cavity C ₁ for molding the Siamese cylinder barrel 1 and the outer wall portion 2. Is formed, and a mold clamping recess 13 that fits into the recess 12 is provided on the upper surface of each of the side molds 10 ₁ to 10 ₄ .

As shown in FIGS. 7 and 8, the lower mold 11 has a molten metal reservoir portion 14 for receiving a molten aluminum alloy from a melting furnace (not shown).
A hot water supply cylinder 15 that communicates with the hot water reservoir 14, a plunger 16 that slides on the hot water supply cylinder 15, and two branches from the hot water reservoir 14 in the longitudinal direction of the first cavity C ₁ and A pair of runners 17 extending over substantially the same length is provided. Further, the lower die 11 has a forming block 18 projecting upward between the runners 17, and the forming block 18 cooperates with the lower half portions of the side dies 10 ₁ to 10 ₄ to form the crankcase 3. Define a second cavity C ₂ for The upper end of the cavity C ₂ is the first
It communicates with Cavity C _1, and the lower ends of both sides are both runways 17
Through a plurality of weirs 19. These first and second cavities C ₁ and C ₂ constitute a cylinder block material forming cavity.

The molding block 18 includes four tall first semi-cylindrical molding parts 18 ₁ formed at predetermined intervals, and adjacent first molding parts 18 ₁ and outermost first molding parts 18 ₁ . more becomes convex-shaped second molded part 18 ₂ located outside, each of the first mold portion 18 ₁ is used to mold the rotation space 20 for the crank pin and the crank arm (second, third panel),
Second forming unit 18 ₂ bearing holder 2 of the crank journal
1 (FIGS. 2 and 3). Each weir 19 is provided corresponding to each second molding portion 18 ₂ .
The molten metal is quickly injected into the large capacity portion of the second cavity C ₂ .

The bottom surface of the runner 17 is formed in a step-like shape of several steps from the side of the hot water reservoir 14 so that the cross-sectional area of both runners 17 gradually decreases from the side of the hot water reservoir 14 toward the runner tip 17a. Each rising portion 17c connected to each step portion 17b is formed obliquely so that the molten metal can be smoothly guided to each weir 19.

When the cross-sectional area of the runner 17 is gradually reduced in this way,
In the part with a large cross-sectional area, a large amount of molten metal is dammed at a slow speed.
The second was injected into cavity C ₂ through, and because the small portion of the cross-sectional area can be injected into the second cavity C ₂ through weir 19 a small amount of the molten metal at a high speed, molten metal runner in its cavity C ₂ It is injected substantially evenly over the entire length of 17. Further, since the molten metal injection work is efficiently performed, the casting efficiency can be improved.

As shown in FIGS. 5 and 6, a positioning projection 22 is formed on each of the first molding portions 18 ₁ and the top surface thereof to which the lower end of the fiber molding F is fitted, and a recess 23 is formed at the center of the positioning projection 22. Is formed. In addition, the two first molding parts located on both sides
₁ , on both sides of the positioning protrusion 22, the first molding portion 18
₁ are formed with through holes 24, and the through holes 24 are formed.
The pair of temporary setting pins 25 are slid on each other. The temporary setting pins 25 are used for temporary setting of a sand core for a water jacket described later. The lower ends of both temporary setting pins 25 are
It is fixed to a mounting plate 26 arranged below the molding block 18. Two support rods 27 are inserted through the mounting plate 26, and a coil spring 28 is contracted between the lower portion of each support rod 27 and the lower surface of the mounting plate 26. When the mold is opened, the mounting plate 26 receives the elastic force of each coil spring 58 and ascends until it comes into contact with the stopper 27a at the tip of each support rod 27, whereby the tip of each temporary installation pin 25 is moved to the first molding portion 18 _1. It protrudes from the top surface. A recess 25a that engages with the lower edge of the sand core is formed on the tip surface of each temporary setting pin 25.

The two first mold portion 18 ₁ positioned at both sides, through-holes 29 penetrating the first mold portion 18 ₁ at the bisecting position between the two through holes 24 are formed, attached to the lower end into the through-holes 29 The operating pin 30 fixed to the plate 26 is slidably engaged. When the mold is opened, the tip of the actuating pin 30 projects into the recess 23, and when the mold is closed, it is pushed down by the core for molding a bore bore, which will be described later.
The molding portion 18 ₁ is adapted to be drawn in from the top surface.

Two core receptacles 31 for permanently installing the sand core are provided in the central portion of the wall defining the first cavity C ₁ in the first and second side molds 10 ₁ and 10 ₂ . Each core receiver 31 has an engagement hole 31a for positioning the sand core, and a sandwiching surface 31b formed on the outer periphery of the opening for sandwiching the sand core.
And consists of.

A plurality of third cavities C _{3 for} communicating with the first cavity C ₁ to overflow the molten metal and a fourth cavity C ₄ for forming the communication port 7 are formed in the mold clamping recess 12 of the upper mold 9. Further, the upper mold 9 is formed with gas vent holes 32 and 33 communicating with the third cavity C ₃ and the fourth cavity C ₄ , respectively.

Closing pins 34 and 35 are loosely inserted into the gas vent holes 32 and 33, respectively, and upper ends of the closing pins 34 and 35 are fixed to a mounting plate 36 disposed above the upper die 9.

Each venting holes 32, 33, both cavity _C 3, _C extending from the communication terminal over a predetermined length upward against ₄ small-diameter portion 32a, 33a is first engaged with each closure pin 34, 35 and a lower end The third cavity C ₃ and the fourth cavity C ₄ can be closed.

A hydraulic cylinder 39 is interposed between the upper die 9 and the upper surface and the mounting plate 36, and the hydraulic cylinder 39 is operated to move the mounting plate 36 up and down to cause the closing pins 34, 35 to close the small diameter portions 32a,
33a is adapted to be opened and closed. 40 is a mounting plate 36
It is a guide rod.

Each cylinder barrel 1 is provided on the top surface of the mold clamping recess 12 of the upper mold 9.
₁ to 1 ₄ on the axis corresponding to the cylinder bores molding cylindrical core 41 which is disposed toward the downward direction is projected, the first mold portion 18 ₁ a top surface on the lower end surface of each core 41 A convex portion 41a that can fit in the concave portion 23 is provided.

9, FIG. 10 shows the water jacket sand core 59, the sand core 59, four cylindrical portion ₆₀ 1 in correspondence with the four cylinder barrels ₁ 1 to 1 ₄ of the cylinder block S 60
₄ , a core main body 61 which is provided with ₄ and lacks a peripheral wall where those adjacent ones overlap with each other, a communication port 7 for communicating the water jacket with the water jacket of the cylinder head, and a reinforcing deck portion 8 should be formed. A plurality of protrusions 62 projectingly provided on the upper end surface of the child main body 61 and both outer surfaces of the core main body 61 in the cylinder barrel arrangement direction, in the illustrated example, the two cylindrical portions 60 ₂ and 60 ₃ located in the middle are both outside It is composed of skirting boards 63 that are respectively provided on the side surfaces. Each skirting board 63 has a large-diameter portion 63a integral with the core body 61, and a small-diameter portion 6 protruding from the end face thereof.
And 3b.

FIG. 11 shows a cylindrical fiber molded body F molded from a mixed fiber of carbon fiber and alumina fiber, the dimensions of which are 89 mm in outer diameter, 78 mm in inner diameter and 152 mm in height, and its bulk density is 0.3 g / It is cm ³ . The fiber molded body F has an average diameter of 18
Carbon fibers having an average length of 0.8 mm (short fibers) and alumina fibers having an average diameter of 3 to 4 μm and an average length of 0.5 mm (short fibers) are mixed at a ratio of 1: 3, and the mixed fibers are obtained. Silica sol is added as a binder to the above, and a suction adhesion molding method is applied to mold. In this case, an alumina sol simple substance or a mixture of silica sol and alumina sol can be used instead of the silica sol.

The suction adhesion molding method, in a tank containing a mixture of the mixed fiber and silica sol, standing up a breathable cylindrical mold with both end surfaces sealed, and applying suction to the inside of the cylindrical mold It means a method of adsorbing the mixture on the outer peripheral surface of the cylinder.

The fiber molded body molded by the above-mentioned method is used after being subjected to a drying process and a firing process after releasing from the mold.

Next, a casting operation of the cylinder block material Sm by the casting apparatus using the fiber molded body F will be described.

First, as shown in FIG. 5, the upper mold 9 is raised, and the opposite molds 10 ₁ , 10 ₂ ; 10 ₃ , 10 ₄ are moved so as to be separated from each other to open the mold. The hydraulic cylinder 39 on the upper die 9 is actuated to raise the closing pins 34, 35 via the mounting plate 36, and the lower ends of the closing pins 34, 35 are moved to the third and fourth positions.
Small diameter portions 32a, 33a communicating with the cavities C ₃ , C ₄
Close the upper openings of each to narrow down the opening of each upper opening.
Further, the plunger 16 in the hot water supply cylinder 15 is lowered.

Each fiber molding F preheated to about 300 ° C. is attached to each core 41, and the upper end opening of the fiber molding F is brought into contact with the top surface of the recess 12 of the upper mold 9.

Fifth, both sides of the cylindrical portion 60 _1, 60 ₄ lower edge of the sand core 59 as shown in FIG. 10, the temporary installation pins projecting into the first top surface of the forming portions 18 ₁ on both sides of the lower mold 11 The sand core 59 is temporarily installed by engaging with the recess 25 a of the sand core 25.

As shown in FIG. 6, the two side molds 10 ₁ and 10 ₂ are moved by a predetermined distance in the direction in which they approach each other, and
The sand core 59 is permanently installed by engaging with the skirting boards 63.
That is, the small diameter portion 63b of each skirting board 63 of the sand core 59 is fitted into the engagement hole 31a of each core receptacle 31 to position the sand core 59, and the cylinder barrel arrangement direction of each large diameter portion 63a. The end face parallel to the abutment surface abuts against the sandwiching surface 31b of each core receiver 31 to sandwich the sand core 59 with the sandwiching surface 31b.

Next, the upper mold 9 is lowered, and each fiber molded body F is moved to the sand core 59.
Of each fiber molded body F inserted into each cylindrical portion 60 _{1 to} 60 _{4 of}
The lower end portion fitted into the positioning projections 22 of, also fitting the core 41 and the convex portion 41a in the first molding portion 18 _concave portion 23 of the top surface. Since operating pin 30 by the recess-projection fitting is pressed draw from the first mold portion 18 ₁ a top face each temporarily installed pin 25 is lowered. Further, the respective protrusions 62 of the sand core 59 are loosely inserted into the respective fourth cavities C _4, and the mold clamping concave portion 1 of the upper mold 9 is further inserted.
2 is fitted in the mold clamping recess 13 of each of the side molds 10 ₁ to 10 ₄ to perform mold clamping.

The molten metal of aluminum alloy (JIS ADC12) at 730 to 740 ° C. is supplied from the melting furnace to the molten metal reservoir 14 of the lower mold 11, and the plunger 16 is raised at a speed of 0.08 to 0.3 m / sec to remove both molten metal. Second from the runway 17 through the weir 19.
Injected from both the bottom of the cavity _{C 2} to the cavity _{C 2} and the first cavity _{C 1.} Both cavities C ₁ , C
The gas such as air in ₂ is pushed up by the molten metal and communicates with the _third and _fourth cavities C ₃ , C ₄ through the gas vent hole 3
After passing through 2, 33, it escapes above the upper mold 9.

In this case, as described above, the cross-sectional area of both runners 17 is 1
Since the bottom of the runway is formed in a step-like shape with several steps from the side of the hot water reservoir 14 so as to decrease gradually toward 7a,
As the plunger 16 rises, the molten metal is injected from both runways 17 through the weirs 19 into the second cavity C ₂ and from both lower portions thereof substantially evenly over the entire length thereof.

Further, when the molten metal is injected into the first and second cavities C ₁ and C ₂ , the degassing holes 32 and 3 are closed by the closing pins 34 and 35.
Since the opening degree of the small diameter portions 32a and 33a in 3 is narrowed, a back pressure is generated in the first and second cavities C ₁ and C ₂ due to the throttling effect of the opening, and the back pressure is applied to the entire molten metal surface. Works equally. As a result, the surface of the molten metal is suppressed from waviness and rises substantially horizontally, which prevents gas from being entrained in the molten metal and efficiently degass the molten metal, thus avoiding the formation of cavities. Due to the back pressure, the injection pressure of the molten metal in the _first and second cavities C ₁ and C ₂ is, as shown in FIG. 12, a pressure p ₁ above atmospheric pressure, for example, 2 to 5 kg /
It becomes cm ² .

Further, since the fiber molded body F is preheated to the above temperature,
The molten metal around the fiber molded body F is kept warm, so that the molten metal is prevented from adhering to the fiber molded body F.

When the molten metal is completely injected into the third and fourth cavities C ₃ and C ₃ , the hydraulic cylinder 39 on the upper die 9 is operated to lower the mounting plate 36, and the closing pins 34 and 35 are used to move both. cavity _C 3, the small diameter portion 32a which communicates with the _{C 4,} to close the 33a.

Then, the plunger 16 is raised at a speed of 0.14 to 0.18 m / sec to hold the molten metal under a high pressure p ₂ higher than the pressure p ₁ , that is, under a pressure of 400 kg / cm ² to completely solidify it. The structure of the aluminum alloy that is the matrix is densified to improve its strength. In the process of increasing the pressure of the molten metal, the molten metal having a pressure of 5 to 20 kg / cm ² and having a high temperature around the fiber molded body F is reliably filled into the fiber molded body F. Since the filling pressure of the molten metal is low as described above, the fiber molded body F is not destroyed by the molten metal during the filling.

The sand core 59 is a double-sided mold 1 through each skirting board 63 thereof.
Since it is clamped in the correct position by 0 ₁ , 10 ₂ ,
Never sand core 59 or lifted at the injection time and pressing time of the molten metal in the cavity C in the _first molten metal into the cavity C _1. The large diameter portion 63a of each skirting board 63
Since the end surface of the sand ball abuts against the sandwiching surface 31b of the core receiver 31 of the double-sided molds 10 ₁ and 10 ₂ , when the sand core 59 tends to swell, its deforming force is supported by each sandwiching surface 31b. As a result, the sand core 59 is prevented from being deformed, and the Siamese cylinder barrel 1 having a uniform wall thickness around each sill bore 4 is obtained.

When the mold is opened after the solidification of the molten metal is completed, the cylinder block material Sm shown in FIG. 4 is obtained.

The cylinder block material Sm each fourth is subjected to grinding into cavity C ₄ and sand the protrusions 62 in concert Removal of each protrusion 64 which is formed by cooperation each communicating port 7 of the core 59 and the reinforcing deck section 8 Is formed, and the water jacket 6 is obtained by sand removal. Further, the inner peripheral surface of each cylinder bore 4 is subjected to perfect circle processing, and other predetermined processing is performed. Cylinder block S shown
Is obtained.

FIG. 13 is a photomicrograph showing the metal structure of the fiber molding F, the aluminum alloy A matrix, and the composite part (100
In the figure, the black dots and the linear portions Fa correspond to alumina fibers, and the gray elliptical portions Fc correspond to carbon fibers.

From FIG. 6, it is clear that the fiber alloy F is almost completely filled with the aluminum alloy A.

The fiber molded body F may be molded from one type of reinforcing fiber. In addition to the aluminum alloy, cast iron, copper, magnesium alloy or the like is used as the matrix.

C. EFFECTS OF THE INVENTION According to the present invention, the molten metal is injected into the cylinder block material forming cavity from the lower portion thereof, and at the same time, gas is degassed from inside the cavity through the opening of the gas vent hole whose opening is narrowed. The back pressure generated in the cavity due to the effect acts evenly on the entire surface of the molten metal, and as a result,
The surface of the molten metal is suppressed from swelling and rises substantially horizontally, which prevents gas from being entrained in the molten metal and also allows efficient degassing.

Further, since the fiber molded body is preheated to 200 ° C. or higher, the temperature of the molten metal around the fiber molded body is kept warm, and thus the adhesion of the molten metal to the fiber molded body is avoided.

In addition, since the molten metal is completely solidified under pressure, the molten metal having a high temperature around the fiber molded body can be efficiently and surely filled into the fiber molded body in the process of increasing the pressure of the molten metal, and the metal structure of the matrix is formed. It can be densified and its strength can be improved.

Therefore, by adopting the above-mentioned method, it is possible to efficiently cast a high-strength fiber-reinforced cylinder block material which is surely fiber-reinforced around the cylinder bore and does not have cavities.

[Brief description of drawings]

1 to 3 show a Siamese type cylinder block made of the material obtained by the present invention, FIG. 1 is a perspective view seen from above, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and 2A.
Fig. 2 is a sectional view taken along line IIa-IIa in Fig. 2, Fig. 3 is a perspective view seen from below, Fig. 4 is a perspective view seen from above of a Siamese type cylinder block material obtained by the present invention, and Fig. 5 is FIG. 6 is a vertical sectional front view when the mold of the casting apparatus is opened, FIG. 6 is a vertical sectional front view when the mold of the casting apparatus is closed, FIG. 7 is a sectional view taken along line VII-VII of FIG. 6, and FIG. 8 is VIII-VIII of FIG. FIG. 9 is a perspective view of the sand core seen from above, FIG. 10 is a sectional view taken along line XX of FIG. 9, FIG. 11 is a perspective view of a fiber molding, and FIG. A graph showing the relationship between pressure and time, and FIG. 13 is a micrograph showing the metal structure of the composite portion of the fiber compact and the aluminum alloy. C ₁ , C ₂ ... First and second cavities constituting a cylinder block material forming cavity, F ... Fiber molded body,
Sm …… Siamese type cylinder block material, 4 ……
Cylinder bore, 32, 33 ... Gas vent hole, 41 ... Core

Continuation of the front page (56) References JP 61-293651 (JP, A) JP 61-293652 (JP, A) JP 62-6762 (JP, A) JP 62-6763 (JP , A)

Claims (1)

[Claims] 1. A cylinder preheated to 200 ° C. or higher on the outer peripheral surface of a core for forming a cylinder bore, the axis of which is arranged vertically when casting a cylinder block material in which the periphery of the cylinder bore is reinforced with a fiber molding. A step of mounting the shaped fiber molded body; a step of narrowing the opening of a gas vent hole in the upper portion of the cylinder block material molding cavity surrounding the fiber molded body, and injecting molten metal into the cavity from the lower portion of the cavity; Close the vent hole and pressurize the molten metal,
A method of casting a fiber-reinforced cylinder block material, comprising the step of completely solidifying under pressure.