JPH0635041B2 - Manufacturing method of fiber reinforced cylinder block - 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 producing a fiber reinforced cylinder block used in an engine, particularly a cylinder fiber reinforced composite body around the cylinder bore.

(2) Conventional Technology Conventionally, in the case of manufacturing the cylinder block, a tubular fiber molded body is arranged in a fiber-reinforced composite molding portion of a mold, and the cylinder block material is pressure-cast and at the same time molten metal is poured into the fiber molded body. Filled to obtain a fiber reinforced composite.

In this case, in order to improve the handleability of the fiber molded body and prevent damage due to the filling pressure of the molten metal, the fiber molded body is formed relatively thick.

(3) Problems to be Solved by the Invention However, when the fiber molded body is formed thick, the following problems occur.

a. When the binder for binding the reinforcing fibers is dried during the production of the fiber molded body, when the binder is dried from the surface of the fiber molded body and an undried portion occurs inside, the desiccant of the undried portion is dried. Since it penetrates into the dried portion, the internal strength of the fiber molding is lowered, and as a result, a fiber-reinforced composite having uniform strength throughout cannot be obtained.

b. The molten metal that has infiltrated into the fiber molding is cooled in the middle and its filling property deteriorates, so the fiber molding is deformed and casting defects such as microporosity and cavities occur, resulting in good shape accuracy and casting quality. Fiber reinforced composites cannot be obtained.

It is an object of the present invention to provide the above manufacturing method which can solve the above conventional problems.

B. Configuration of the invention (1) Means for solving the problem The present invention, in producing a fiber-reinforced cylinder block composed of a tubular fiber-reinforced composite around the cylinder bore,
A thin-walled tubular fiber molded body fitted with a metal-reinforcing cylinder having good machinability inside is disposed in the fiber-reinforced composite molding portion of the mold, and the cylinder block material is pressure-cast at the same time as the fiber molded body. And a step of filling the melt with molten metal to obtain the fiber-reinforced composite; and a step of cutting and removing the reinforcing cylinder from the cylinder block material to form the cylinder bore.

(2) Action Since the fiber molded body is formed thin as described above, when the fiber molded body is dried, the binder is uniformly dried over the entire fiber molded body by improving the heat flow to the fiber molded body, A defect such as a decrease in internal strength can be eliminated, whereby a fiber-reinforced composite body having uniform strength over the whole can be obtained.

Further, since the molten metal can be easily filled into the fiber molded body, the fiber molded body is not deformed, and casting defects such as microporosity do not occur, and the fiber reinforced composite body has good shape accuracy and casting quality. Can be obtained.

Further, even if the fiber molded body is formed into a thin wall, it is reinforced by the reinforcing tube, so that it is easy to handle and is not damaged by the filling pressure of the molten metal. Since the reinforcing cylinder is easily removed by cutting, the dimensional accuracy is good, and the fiber-reinforced cylinder bore around the periphery can be easily obtained.

(3) Example FIGS. 1 to 3 show a fiber-reinforced aluminum alloy Siamese type cylinder block S obtained by the present invention.
Its cylinder block S has a plurality arranged in series, the illustrated example the Siamese cylinder barrel 1 composed by combining four cylinder barrels 1 ₁ to 1 _4, the outer wall 2 which surrounds the Siamese cylinder barrel 1, the outer wall portion 2 and a crankcase 3 connected to the lower edge of the crankcase 3. Around the cylinder bore ₄ in each of the cylinder barrels 1 ₁ to 14 is composed of a tubular fiber reinforced composite Cf.

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 plurality of reinforcing deck parts 8 are partially connected to each other, and the adjacent reinforcing deck parts 8 have a communication port 7 to the cylinder head side.
Function as. 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 for casting m. The apparatus is provided with a mold M as a mold, the mold M is a vertically movable upper mold 9, and is arranged below the upper mold 9, In the drawing, the left and right halves are divided into first and second side molds 10 ₁ , 10 ₂ and a seventh mold.
In the figure, the left and right halves are divided into third and fourth side molds 10 ₃ , 1
0 ₄ and a lower mold 11 on which the side molds 10 ₁ to 10 ₄ are slidably mounted.

A mold clamping recess 12 is formed on the lower surface of the upper mold 9, and the recess 12 cooperates with the upper half of each side mold 10 ₁ to 10 ₄ to mold the Siamese cylinder barrel 1 and the outer wall 2. Define Cavity C ₁ . Therefore, the first cavity C ₁ functions as a fiber-reinforced composite molding part. Each of the side molds 10 ₁ to 10 has a mold clamping protrusion 13 that fits into the recess 12.
₄ is projected on the upper surface.

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).
When a hot water supply cylinder 15 to be connected to the the basin portion 14, a plunger 16 is engaged slidably in the hot water cylinder 15, in a first longitudinal direction of the cavity C ₁ is branched into two from the basin section 14, and therewith 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.

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. Therefore, the molten metal does not cause a turbulent flow in the cavity C ₂ , and it is possible to prevent gas such as air from being caught in the molten metal and avoid the formation of cavities.
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 provided on the top surface of each of the first molding portions 18 _{1 so} as to erect a fiber molding to be described later, and a recess 23 is formed at the center of the positioning projection 22. To be done. Also, the two first molding parts 18 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.
A pair of temporary setting pins 25 are slidably engaged with 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 28 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 operating pin 30 projects into the recess 23,
Further, when the mold is closed, it is pushed down by a mandrel described later, so that both temporary setting pins 25 can be pulled in from the top surface of the first molding portion 18 ₁ .

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 opened in the mold clamping recess 12 of the upper mold 9. In addition, the upper mold 9 is formed with gas vent holes 32, 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.

Small-diameter portions 32a and 33a extending upward from the communication ends of the gas vent holes 32 and 33 to the cavities C ₃ and C ₄ for a predetermined length are fitted to the lower end portions of the closing pins 34 and 35, respectively. The third cavity C ₃ and the fourth cavity C ₄ can be closed.

A hydraulic cylinder 39 is interposed between the top surface of the upper die 9 and the mounting plate 36, and the mounting plate 36 is moved up and down by the operation of the hydraulic cylinder 39 to cause the closing pins 34, 35 to move 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 _{1 on the} top surface of the mold clamping recess 12 of the upper mold 9.
To 1 ₄ in response to, on the axis, the mandrel toward the downward direction 41
And a convex portion 41a that can be fitted into the concave portion 23 of the top surface of the first molding portion 18 ₁ is provided on the lower end surface of each mandrel 41. Further, the outer peripheral surface of the mandrel 41 is formed into a tapered surface that tapers from the upper end to the lower end.

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
_{In order} to form a core main body 61 which is provided with ₄ and lacks peripheral walls where 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, A plurality of projections 62 projecting from the upper end surface of the child body 61, and a skirting board 63 projecting from both outer surfaces of the two cylindrical portions 60 ₂ and 60 ₃ located in the middle of the core body 61. It is composed of Each skirting board 63 is formed of a large-diameter portion 63a integral with the core body 61 and a small-diameter portion 63b projecting from the end surface thereof.

In FIG. 11, a tubular fiber molding F is molded from a mixed fiber of carbon fiber and alumina fiber, and its dimensions are 82 mm in outer diameter, 78 mm in inner diameter, and 152 mm in height, and therefore the wall thickness is 2 mm. And thin. The bulk density is 0.3
Is a ~1.2g / cm ^3. The fiber molded body F has an average diameter of 18μ.
m, carbon fiber (short fiber) with an average length of 0.8 mm, and alumina fiber (short fiber) with an average diameter of 3 to 4 μm and an average length of 0.5 mm.
And are mixed at a ratio of 1: 3, silica sol is added as a binder to the mixed fibers, and a suction adhesion molding method is applied to mold. Instead of the silica sol, it is possible to use an alumina sol simple substance or a mixture of silica sol and alumina 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 a suction action to the inside of the cylindrical mold, It means a method of adsorbing the mixture on the outer peripheral surface of the cylinder.

The fibrous molded body F molded by the above-mentioned method is used after undergoing a drying and firing process after release. In this drying step, since the fibrous molded body F is thin, the heat distribution is good, and therefore the binder is uniformly dried over the whole.

A reinforcing cylinder T made of a metal having good machinability, for example, an aluminum alloy, cast iron, or the like is fitted inside the fiber molded body F, which improves the handleability of the thin and fragile fiber molded body F. ing. The inner peripheral surface of the reinforcing tube T is formed into a tapered surface so that it can be fitted with the mandrel 41.

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

First raise the upper die 9, as shown in FIG. 5, also moves to one another apart from the double-sided 10 _1, 10 2, _{10 3,} 10 ₄ which faces performing mold opening. The hydraulic cylinder 39 on the upper die 9 is operated to raise the closing pins 34, 35 via the mounting plate 36, and the third and fourth cavities C ₃ ,
Small-diameter portion 32a which communicates with the C _4, open each upper opening of 33a. Further, the plunger 16 in the hot water supply cylinder 15 is lowered.

As shown in FIG. 5, the lower opening of the reinforcing cylinder T having the fiber molded body F preheated to approximately 300 ° C. is fitted into the positioning protrusion 22 of the first molding portion 18 ₁ to move the fiber molded body F to the first position. Molding part 1
Set up at 8 ₁ .

Further, as shown in FIGS. 5 and 10, the lower edges of the cylindrical portions 60 ₁ and 60 ₄ on both sides of the sand core 59 are connected to the first molding portions 1 on both sides.
8 is engaged with the recess 25a of the temporary installation pins 25 protruding to _one of the top surface performing temporary installation of the sand core 59. Each cylinder ₆₀ through 603 ₄ of the sand core 59 is disposed on the outer periphery of each fiber molding F.

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. The other two-sided molds 10 ₃ and 10 ₄ are also moved in the same manner.

Next, the upper die 9 is lowered, the mandrel 41 is taper-fitted to the reinforcing cylinder T, and the upper end surfaces of the fiber molded body F and the reinforcing cylinder T are recessed.
The fiber molded body F is positioned and fixed by abutting against the top surface of No. 2. Further, the convex portion 41a of the mandrel 41 has the first molding portion 18
Since it fits in the recess 23 of the _first top surface, the operating pin 30 is pushed down and each temporary setting pin 25 is pulled in from the top surface of the first molding portion 18 ₁ . Further, the respective protrusions 62 of the sand core 59 are loosely inserted into the respective fourth cavities C _4, and the concave portions 12 of the upper mold 9 are fitted into the convex portions 13 of the respective side molds 10 ₁ to 10 ₄ to perform mold clamping. Be seen.

A molten metal composed of an aluminum alloy (JIS ADC12) at 730 to 740 ° C. is provided to the molten metal reservoir 14 of the lower mold 11 to raise the plunger 16 at a speed of 0.08 to 0.3 m / sec, as shown in FIG. As described above, the molten metal with pressure p ₁ is passed from both runways 17 through the weir 19 to the cavities C ₂ and the first cavities C ₁ from both lower portions of the second cavity C _2.
Inject. Gases such as air in both cavities C ₁ and C ₂ are pushed up by the molten metal, and the third and fourth cavities C
₃ , the upper mold 9 through the gas vent holes 32, 33 communicating with C ₄
Exit above.

In this case, the cross-sectional area of both runways 17 is as described above.
Since the bottom of the runway is formed on several upstairs from the side of the hot water reservoir 14 so as to decrease in a stepwise manner toward a, the plunger 16 is lifted so that the molten metal flows from both runways 17 to each weir 1
Through 9 the second cavity C ₂ is injected substantially evenly from the lower portions of the second cavity C ₂ over its entire length.

Further, since the openings of the small diameter portions 32a, 33a of the gas vent holes 32, 33 are narrowed, when the molten metal is injected into the first and second cavities C ₁ , C ₂ , the cavities C ₁ ,
A back pressure is generated in C ₂ , and the back pressure acts evenly on the entire molten metal surface. 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,
In addition, degassing is also performed efficiently, so that generation of nests is avoided. Due to the back pressure, the injection pressure of the molten metal in the _first and second cavities C ₁ and C ₂ is a pressure p ₁ higher than the body pressure, for example, 2 to 5 kg / cm ^{2 as} shown in FIG.
become.

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 poured into the third and fourth cavities C ₃ and C ₄ , the hydraulic cylinder 39 on the upper mold 9 is operated to lower the mounting plate 36, and the closing pins 34 and 35 are used to move both cavities C and C. _3, the small diameter portion 32a which communicates with the _{C 4,} 33a
To close.

After that, the plunger 16 is raised at a speed of 0.14 to 0.18 m / sec to melt the molten metal under a high pressure p ₂ which exceeds the pressure p ₁ .
That is, the fiber-reinforced composite Cf is obtained by keeping it under a pressure of 400 kg / cm ² for a predetermined time, and the molten metal is completely solidified under this high pressure to densify the structure of the aluminum alloy and to improve its strength. In the process of increasing the pressure of the melt, the pressure of the melt 5 to
The molten metal is filled in the fiber molded body F at 20 kg / cm ² . 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 filling. Also in this case,
Since the fiber molded body F is thin, the molten metal can be efficiently filled,
Moreover, the fiber-reinforced composite Cf can be obtained with certainty and without causing deformation of the fiber molding F and casting defects such as microporosity.

When the thin fiber molded body F is directly fitted to the mandrel 41, when a gap is formed between them, the fiber molded body F may be damaged by the filling pressure of the molten metal. Since the body F is reinforced by the reinforcing tube T fitted therein, the fiber molded body F is not damaged by the filling pressure of the molten metal.

The sand core 59 is a double-sided mold 1 through each skirting board 63 thereof.
Since it is clamped by 0 ₁ , 10 _{2 in the} correct position,
The sand core 59 does not float when the molten metal is poured into the first cavity C ₁ and when the molten metal in the cavity C ₁ is pressurized. Also, the large diameter portion 6 of each skirting board 63
The end face of 3a has a core holder 31 in the double-sided molds 10 ₁ and 10 ₂ .
When the sand core 59 has a tendency to swell, its deforming force is supported by each of the sandwiching surfaces 31b, which prevents the sand core 59 from being deformed and prevents the cylinder bores from deforming. A Siamese cylinder barrel 1 having a uniform wall thickness of 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.

When the cylinder block material Sm is ground to remove the protrusions 64 formed by the cooperation of the fourth cavities C ₄ and the protrusions 62 of the sand core 59, the protrusions 62 cause the communication port 7 to move. Reinforcing deck portions 8 are formed between the adjacent communication ports 7, and the water jacket 6 is obtained by further removing sand. After that, when the reinforcing cylinder T is removed by cutting to form the cylinder bore 4, as shown in FIGS. 1 to 3, a cylinder block S composed of the tubular fiber reinforced composite Cf around the cylinder bore 4 is obtained.

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

C. EFFECTS OF THE INVENTION According to the present invention, since the fiber molded body is formed into a thin wall, when the fiber molded body is dried, the binder is uniformly dried over the fiber molded body by improving the heat flow to the fiber molded body, A defect such as a decrease in internal strength can be eliminated, and a fiber-reinforced composite having uniform strength over the whole can be obtained.

Further, since the molten metal can be easily filled into the fiber molded body, the fiber molded body is not deformed, and casting defects such as microporosity do not occur, and the fiber reinforced composite body has good shape accuracy and casting quality. Can be obtained.

Further, even if the fiber molded body is formed into a thin wall, it is reinforced by the reinforcing tube, so that it is easy to handle and is not damaged by the filling pressure of the molten metal. Since the reinforcing cylinder is easily removed by cutting, the dimensional accuracy is good, and the fiber-reinforced cylinder bore around the periphery can be easily obtained.

[Brief description of drawings]

1 to 3 show a Siamese type cylinder block 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 FIG. Figure 2
IIa-IIa sectional view, FIG. 3 is a perspective view seen from below, FIG. 4 is a perspective view seen from above of the Siamese type cylinder block material, FIG. 5 is a vertical sectional front view when the mold of the casting machine is opened, FIG. 6 is a vertical sectional front view of the casting apparatus when the mold 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.
FIG. 0 is a sectional view taken along line XX of FIG. 9, FIG. 11 is a perspective view of the fiber molded body, and FIG. 12 is a graph showing the relationship between the pressure of the molten metal and time. C ₁ ... 1st cavity as a fiber reinforced composite molded part, Cf ... Fiber reinforced composite, F ... Fiber molded body, M ...
... Mold as mold, Sm ... Siamese type cylinder block material, T ... Reinforcing cylinder

Claims (1)

[Claims] 1. A thin-walled tubular fiber molding in which a metal-reinforcing cylinder having good machinability is fitted inside when producing a fiber-reinforced cylinder block having a tubular fiber-reinforced composite body around a cylinder bore. Is disposed in the fiber-reinforced composite molding part of the mold, and the cylinder block material is pressure-cast, and at the same time, the fiber molding is filled with a molten metal to obtain the fiber-reinforced composite material; A step of cutting and removing a cylinder to form the cylinder bore; and a method of manufacturing a fiber-reinforced cylinder block.