JP2001150097A - Molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding device wherein a slide core 28R is arranged, within a pair of main mold 11R which produces casting products by opening or closing action in such a way of approaching to or departing from each other, to move freely in opposite directions against open/close directions of the main mold 11R, and concavities are formed in the interior of the products by the slide core 28R, and further the slide core 28R with lower degree of draft is allowed to release requiring no specific driving source. SOLUTION: By lifting a driven cam 31a, formed at one end of a lever 31R which is pivotally supported with bearing pin 30, under pressed contact with a driving cam 34b which moves together with the main mold 11R in the direction of opening, a driving element 31b formed at other end of the lever 31R is made to move downward, the slide core 28R connected with the driving element 31b by a link 35 and a bolt Bi is pull down obliquely and forcibly, and the products is released first from the concavities of the products.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pair of main dies for casting products by opening and closing so as to approach and separate from each other, and a slide core movable in a direction different from the opening and closing direction of the main dies. The present invention relates to a mold apparatus that is arranged and that forms a recess inside a product with the slide core.

[0002]

2. Description of the Related Art When a product having a complicated shape such as a piston for an internal combustion engine is cast by gravity casting, a concave portion inside the product is formed using a slide core. The slide core arranged parallel to the opening and closing direction of the main mold does not require a special drive source for pulling out to move back and forth with the main mold, but is arranged to be inclined with respect to the opening and closing direction of the main mold. The slide core is pulled out of the product using a special drive source.

[0003]

In order to smoothly release the slide core from the product, it is necessary that the slide core has a predetermined draft. If a large draft angle can be secured, the slide core can be released from the product with a relatively small driving force.However, if a large draft angle cannot be secured due to the design requirements of the recess, the slide core is driven. Therefore, a large output power source is required as a driving source, which causes a problem that the die apparatus becomes large and the cost increases.

The present invention has been made in view of the above circumstances, and has as its object to smoothly release a slide core having a small draft without requiring a special drive source.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, it is possible to approach each other.
A slide core that is movable in a direction different from the opening / closing direction of the main mold is arranged inside a pair of main molds for casting a product by opening and closing so as to separate from each other, and a concave portion is formed inside the product with the slide core. In the mold apparatus, a lever pivotally supported on a fixed base via a fulcrum pin, a driven cam provided on the lever, a driving cam that moves by the opening operation of the main mold and abuts on the driven cam, And a drive unit connected to the slide core. The drive cam, which is moved by the opening operation of the main mold, is brought into contact with the driven cam to swing the lever around the fulcrum pin. A mold apparatus characterized in that the mold apparatus is moved in a mold release direction.

According to the above construction, when the main mold is opened after the main mold is clamped and the product is cast, the driving cam moved by the opening operation of the main mold comes into contact with the driven cam of the lever to move the lever. In order to swing around the fulcrum pin, the slide core connected to the drive unit of the lever moves in the releasing direction. As a result, even when the release of the slide core is difficult due to a small draft angle, the slide core is forcibly moved in the release direction in conjunction with the opening operation of the main die, thereby enabling reliable release. This makes it possible to reduce the draft and increase the degree of freedom in designing the shape of the end face or wall surface of the recess. In addition, since no special drive source is required to move the slide core, it is possible to contribute to reduction in the number of parts and cost.

According to the second aspect of the present invention,
In addition to the configuration of the first aspect, a return driven cam is provided on the lever, and the return drive cam, which is moved by the closing operation of the main die, is brought into contact with the return driven cam, thereby swinging the lever around the fulcrum pin. A mold apparatus characterized by moving the slide core to the original position is proposed.

According to the above construction, when the main mold is clamped, the return drive cam comes into contact with the return driven cam, the lever swings around the fulcrum, and the slide core connected to the lever automatically moves to the original position. Therefore, a special drive source for returning the slide core to the original position is not required.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

1 to 18 show one embodiment of the present invention. FIG. 1 is a bottom view of a piston for an internal combustion engine, and FIG.
3 is a longitudinal sectional view of a gravity casting mold,
4 is a view showing a state in the middle of mold opening, FIG. 5 is a view in the direction of arrow 5 in FIG. 3, FIG. 6 is a sectional view taken along line 6-6 in FIG. 3, FIG. 8 is a sectional view taken along line 8-8 in FIG. 3, and FIG.
10 is a sectional view taken along line 9-9, FIG. 10 is a sectional view taken along line 10-10 in FIG. 6, FIG. 11 is a sectional view taken along line 11-11 in FIG. 6, and FIG.
12 is a sectional view taken along line 12-12, FIG. 13 is a sectional view taken along line 13-13 in FIG. 12, FIG. 14 is an operation explanatory view corresponding to FIG.
FIG. 18 to FIG. 18 are process drawings of the piston.

FIGS. 1 and 2 show a piston P for an internal combustion engine before machining, which is taken out of a gravity casting mold. The piston P has a columnar shape extending below a circular top surface 1. A ring land portion 2 and a pair of skirt portions 3, 3 continuing downward from both ends in the diameter direction of the ring land portion 2;
And a pair of walls 4, connecting the pair of skirts 3, 3
4, a bag-shaped space 5 surrounded by the skirts 3, 3 and the walls 4, 4, and a pair of bosses 7, provided in the walls 4, 4, through which the piston pin holes 6, 6 penetrate. 7, and a pair of recesses 8, 8 are formed between the ring land portion 2 and the boss portions 7, 7 for lightening. End faces 7a, 7a of the boss portions 7, 7 facing the concave portions 8, 8 are parallel or slightly inclined with respect to a center plane C orthogonal to the axis L of the piston pin holes 6, 6 of the piston P (FIG. 2).

Next, the structure of a gravity casting mold will be described with reference to FIGS. The gravity casting mold is piston P
Has a symmetrical structure with respect to the center plane C of FIG.

[0013] The gravity casting mold is located on the left and right sides of the center plane C.
It has a pair of divided main molds 11L and 11R. Main type 1
1L and 11R are for molding the outer surfaces of the ring land portion 2 and the skirt portions 3 and 3 of the piston P, and four bolts Ba and
It is fixed at Ba and opens and closes in the left-right direction with a drive source (not shown) (see FIG. 5). Casting pin guides 13L, 13R are provided on the left and right main dies 11L, 11R respectively with two bolts Bb, B.
b, and these cast pin guides 13L,
Casting pins 14L and 14R for casting the piston pin holes 6 and 6 are slidably supported by the boss portions 7 and 7 of the piston P at 13R. The cast pins 14L, 14R slide in the left-right direction relative to the cast pin guides 13L, 13R by a drive source (not shown). A disc-shaped top core 15 that can be moved up and down by a drive source (not shown) is closed left and right main molds 11.
The top surface 1 which fits into the upper surface opening of L, 11R and continues above the ring land 2 of the piston P is formed.

A bag-shaped space 5 open to the lower surface and surrounded by the skirts 3 and 3 and the walls 4 and 4 of the piston P includes a pair of side cores 16L and 16R and both side cores 16L and 16L.
It is formed by the center core 17 sandwiched between 6Rs. The left and right side cores 16L, 16R are fixed to the side core holders 18L, 18R with bolts Bc, Bc, respectively, and are opened and closed in the left and right directions by a drive source (not shown). The side cores 16 correspond to the bosses 7, 7 of the piston P.
Undercut portions 16a, 16a on the outer surfaces of L, 16R
(See FIG. 7) is formed.

As is clear from FIGS. 12 and 13,
The center core 17 includes an inner member 19 and a pair of outer members 20 disposed on both front and rear sides of the inner member 19.
20. The inner member 19 fixed by bolts Bd to the upper surface of the center core holder 21 that moves up and down by a drive source (not shown) is in the front-rear direction (the direction perpendicular to the plane of FIG. 4).
Taper surfaces 19a and 19 in which the width of
a pair of front and rear outer members 20, 20 are engaged with the dovetail grooves 19b, 19a on the tapered surfaces 19a, 19a.
b (see FIG. 13) to be slidably supported.

At the lower ends of the front and rear outer members 20, 20, guide pins 22 parallel to the tapered surfaces 19a, 19a are provided.
The guide pins 22, 22 are slidably fitted in guide holes 23, 23 formed in the inner member 19 and the center core holder 21, and are urged upward by springs 24, 24. You. Guide pin 2
Flange-shaped stopper 2 formed at the intermediate portion between the two
2a, 22a function as receiving seats for the springs 24, 24 and regulate the maximum sliding amount of the outer members 20, 20 with respect to the inner member 19. Undercut portions 20a, 20a whose width in the front-rear direction is reduced are formed on upper portions of the outer members 20, 20.

A rectangular flange 26a of an annular mold ring 26 installed on the upper surface of the fixed base 25 is connected to a pair of front and rear mold ring holders 27, 27 fastened to the fixed base 25 by a total of four bolts Be ... from above. It is pressed and fixed (see FIG. 6). Mold ring 26,
A pair of left and right slide cores 28L, 28R is provided in the space between the main molds 11L, 11R and the side cores 16L, 16R.
R is arranged. The slide cores 28L and 28R are used to form recesses 8 and 8 (see FIG. 2) for lightening outside the walls 4 and 4 of the piston P, and the end faces 7a and 7a of the bosses 7 and 7 are formed. It has end faces 28a, 28a to be molded.

At the time of mold clamping, the outer surfaces of the slide cores 28L, 28R are in close contact with the inner surfaces of the main dies 11L, 11R, and the side walls 4, 4 of the piston P are provided between the inner surfaces of the slide cores 28L, 28R and the outer surfaces of the side cores 16L, 16R. A cavity for forming the bosses 4 and the bosses 7, 7 is defined. In addition, the positioning portion 1 in which the cast pins 14L and 14R are inclined at 0 ° to 5 °.
4a, 14a penetrate through the pin fitting holes 28b, 28b of the slide cores 28L, 28R, and have tapered portions 14b,
14b contacts the outer surfaces of the side cores 16L and 16R.
Then, a gap δ is formed between the lower surfaces of the slide cores 28L and 28R and the upper surface of the mold ring 26 (see FIG. 7).

As shown in FIGS. 6, 7 and 9 to 11, two fulcrum pin holders 29, 29 are fixed to the left and right upper surfaces of the flange 26a of the mold ring 26 by bolts Bf, Bf, respectively. Fulcrum pins 30 and 3 erected in the front-rear direction between two fulcrum pin holders 29
The intermediate portion between the levers 31L and 31R is pivotably supported at 0. The inner ends of the levers 31L and 31R are molded rings 2
6 and the main molds 11L, 11R, extend loosely through openings 32, 32 (see FIG. 10) formed in the left and right side surfaces, and extend into the mold ring 26.

A pair of guide keys 33, 33 are fixed to the left and right upper surfaces of the flange 26a of the mold ring 26 by bolts Bg, Bg so as to be located on both front and rear sides of the pair of fulcrum pin holders 29, 29. A pair of guide keys 33,
33, horizontal guide surfaces 33a, 33a are formed on the upper surface, and these guide surfaces 33a, 33a are
It can contact guide surfaces 11a, 11a formed on the lower surface of 11R.

Ejector blocks 34, 34 formed in a U-shape are provided on bolts Bh, Bh on the inner surfaces of the main mold holders 12L, 12R facing the outer surfaces of the main dies 11L, 11R, respectively.
(See FIGS. 7 and 11). Slant drive cams 34b, 34b are formed on the upper surfaces of the central portions of the ejector blocks 34, 34. These drive cams 34b, 34b are inclined driven cams 31a, 31a formed on the lower surfaces of the outer ends of the levers 31L, 31R. Can be abutted.

As is apparent from FIGS. 7 and 9, the molding rings 26 are provided on the lower surfaces of the slide cores 28L and 28R.
35, 35 are supported by two bolts Bi, Bi on the left and right, respectively, which loosely penetrate through
Washers 36 and 36 are supported by one bolt Bj on each of the left and right which loosely penetrates through and the collar 37. And drive units 31b, 31b provided at the inner ends of the left and right levers 31L, 31R.
Are the links 35 and 35 and the washers 36 and 3 respectively.
Fit between 6.

As is apparent from FIG. 7, the levers 31L, 31L,
Returned driven cams 31c, 3 inclined to the upper surface of the outer end of 31R
1c, and the return driven cams 31c, 3c
Return drive cams 12a, 12a capable of contacting 1c are formed on the main mold holders 12L, 12R.

Next, the operation of the embodiment of the present invention will be described.

First, as shown in FIGS. 3 and 15A, the gravity casting mold is clamped. In the mold for gravity casting in the clamped state, the left and right main dies 11L and 11R for forming the ring land 2 and the skirts 3 and 3 of the piston P approach each other and fit on the outer peripheral surface of the mold ring 26. And a top core 15 for forming the top surface 1 of the piston P.
Descends and fits into the upper surface openings of the main dies 11L and 11R.

The left and right side cores 16L, 16R and the center core 17, which form the space 5 in the piston P, are located at the rising end with their upper ends flush with each other. The slide cores 28L, 28R for forming the concave portions 8, 8 outside the wall portions 4, 4 of the piston P are at the ascending position, and the cast pins 14L, 14B are inserted into the pin insertion holes 28b, 28b.
The R positioning portions 14a, 14a are closely fitted and positioned.

Subsequently, as shown in FIG. 15 (b), after the top core 15 is raised to release the top surface 1 of the piston P from the mold, first, as shown in FIGS. 4 and 16 (c), The cast pins 14L, 14R are pulled out in the left-right direction with respect to the main dies 11L, 11R, so that the piston pin holes 6, 6 of the boss portions 7, 7 of the piston P are separated from each other.
The ring land portion 2 and the skirt portions 3 and 3 of the piston P are separated from each other by opening 11R left and right.

As the main dies 11L and 11R move in the left-right direction, the main die holder 12 integrated with the main dies 11L and 11R is moved.
The drive cams 34b, 34b of the eject blocks 34, 34 fixed to the L, 12R abut against the driven cams 31a, 31a at the outer ends of the levers 31L, 31R and press upward, so that the levers 31L, 31R are fulcrum pins 30. , 30 and the inner ends of the drive units 31b, 31b descend. As a result, the drive units 31b of the levers 31L and 31R,
Slide core 2 with links 35, 35 pressed by 31b
8L, 28R are lowered by the gap δ (see FIG. 7), and the end faces 28a, 28a of the slide cores 28L, 28R are recessed 8, 8 of the piston P and the end faces 7a, 7a of the bosses 7, 7.
(See FIG. 2).

The boss portions 7 facing the concave portions 8 of the piston P
7, the end faces 7a and 7a and the end faces 4a and 4a (see FIG. 2) of the wall 4 have extremely small draft angles.
a, 7a; slide core 28L for molding 4a, 4a;
It becomes difficult to release the end faces 28a, 28a of the 28R,
In this embodiment, as the main dies 11L, 11R move in the left-right direction, the slide cores 28L,
28R is forcibly lowered obliquely in a direction away from the center plane C of the piston P (see the arrow A in FIG. 7), so that the end faces 7a, 7a of the bosses 7, 7 and the end faces 4a, 4a, 4a to end surface 2 of slide cores 28L and 28R
The molds 8a and 28a can be surely separated from each other. Moreover, the lowering of the slide cores 28L, 28R is performed by the main mold 11L, 1
Since this is automatically performed in conjunction with opening of the mold in the left and right direction of the 1R, a special drive source is not required.

Subsequently, FIG. 12, FIG. 14 and FIG.
As shown in (d), the left and right side cores 16L, 1L are left in a state where the ring land portion 2 of the piston P is chucked.
The inner member 19 of the center core 17 sandwiched between the 6Rs is lowered together with the center core holder 21. Even if the inner member 19 of the center core 17 is lowered, the outer members 20, 20 urged upward by the springs 24, 24 and the guide pins 22, 22 do not immediately lower,
Initially held at its original height. Therefore, the outer member 2
When the inner member 19 descends relatively to the inner member 19, the tapered surfaces 19a, 19
Outer member 2 with dovetail engagement 19b, 19b with 9a
The undercut portions 20a and 20a move away from the inner wall surface of the space portion 5 of the piston P.

When the stoppers 22a of the guide pins 22, 22 act as the inner member 19 further descends, the outer members 20, 20 together with the inner member 19 are actuated.
Starts descending, and the center core 17 including the inner member 19 and the outer members 20 and 20 is separated from the space 5 of the piston P downward.

Subsequently, as shown in FIG. 17 (e), the left side core 16L is moved rightward together with the side core holder 18L so as to be separated from the space 5 of the piston P, and thereafter, as shown in FIG. 17 (f). As shown in FIG.
The left side core 16 </ b> L is pulled downward and detached from the space 5 while preventing the L undercut portion 16 a from interfering with the boss portion 7 of the piston P.

Further, as shown in FIG. 18 (g), the right side core 16R is moved to the left together with the side core holder 18R so as to be separated from the space 5 of the piston P, and then to FIG. 18 (h). As shown, by pulling out the piston P upward, the piston P can be removed from the gravity casting mold while avoiding the undercut portion 16a of the side core 16R from interfering with the boss portion 7 of the piston P.

After removing the piston P, the gravity casting mold is clamped in the reverse order. In the process of mold clamping, the main mold holders 12L, 1R together with the left and right main molds 11L, 11R.
When the 2R moves in the closing direction, the main mold holders 12L, 12L
The return drive cams 12a provided on the R
Returned driven cam 31 provided on the upper surface of the outer end of 1L, 31R
7 and 31c, and swings the levers 31L and 31R around the fulcrum pins 30 and 30 from the chain line position to the solid line position in FIG. As a result, the drive units 31 of the levers 31L and 31R
b, 31b rise to raise the slide cores 28L, 28R to their original positions. As described above, since the slide cores 28L, 28R are automatically returned to the original positions in accordance with the closing operation of the main dies 11L, 11R, a special drive source becomes unnecessary, and the number of parts and cost can be reduced. .

Although the embodiments of the present invention have been described in detail, various design changes can be made in the present invention without departing from the gist thereof.

For example, in the embodiment, the piston P for the internal combustion engine is illustrated as a product, but the present invention is not limited to this.
The present invention can be applied to any product having the concave portions 8, 8 formed by L, 28R. In the embodiment, levers 31L, 3 pivotally supported at the intermediate portions by fulcrum pins 30, 30.
The driven cams 31a and 31a and the driving unit 3 are provided at both ends of the 1R.
Although 1b and 31b are provided, the positional relationship between the fulcrum pins 30, 30, the driven cams 31a, 31a, and the driving units 31b, 31b can be changed as appropriate.

[0037]

As described above, according to the first aspect of the present invention, when the main mold is opened after the main mold is clamped and the product is cast, the drive cam moved by the opening operation of the main mold. Abuts on the driven cam of the lever to swing the lever around the fulcrum pin, so that the slide core connected to the drive unit of the lever moves in the releasing direction. As a result, even when the release of the slide core is difficult due to a small draft angle, the slide core is forcibly moved in the release direction in conjunction with the opening operation of the main die, thereby enabling reliable release. This makes it possible to reduce the draft and increase the degree of freedom in designing the shape of the end face or wall surface of the recess. In addition, since no special drive source is required to move the slide core, it is possible to contribute to reduction in the number of parts and cost.

According to the invention described in claim 2,
When the main mold is clamped, the return drive cam comes into contact with the return driven cam and the lever swings around the fulcrum, and the slide core connected to the lever automatically returns to the original position. A special drive source for returning to the position is not required.

[Brief description of the drawings]

FIG. 1 is a bottom view of an internal combustion engine piston.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a longitudinal sectional view of a gravity casting mold.

FIG. 4 is a diagram showing a state in the middle of mold opening.

FIG. 5 is a view in the direction of arrows in FIG. 3;

FIG. 6 is a sectional view taken along line 6-6 in FIG. 3;

FIG. 7 is an enlarged view of part 7 of FIG.

8 is a sectional view taken along line 8-8 in FIG. 3;

9 is a sectional view taken along line 9-9 in FIG. 6;

FIG. 10 is a sectional view taken along line 10-10 of FIG. 6;

FIG. 11 is a sectional view taken along line 11-11 of FIG. 6;

FIG. 12 is a sectional view taken along line 12-12 of FIG. 4;

13 is a sectional view taken along line 13-13 of FIG.

FIG. 14 is an operation explanatory view corresponding to FIG. 12;

FIG. 15 is a first partial view of a piston casting process diagram.

FIG. 16 is a second partial view of a piston casting process diagram.

FIG. 17 is a third partial view of a piston casting process diagram.

FIG. 18 is a fourth sectional view of a piston casting process diagram.

[Explanation of symbols]

 P Piston (Product) 8 Concave portion 11L Main die 11R Main die 12a Return drive cam 25 Fixed portion 28L Slide core 28R Slide core 30 Support pin 31L Lever 31R Lever 31a Driven cam 31b Drive 31c Return driven cam 34b Drive cam

Claims (2)

[Claims] 1. A pair of main molds (11L, 11R) for casting a product (P) by opening and closing so as to approach and separate from each other, and a direction different from the opening and closing directions of the main molds (11L, 11R). A movable slide core (28L, 28R) is arranged on the product, and the product (P) is formed with the slide core (28L, 28R).
A mold device for forming a concave portion (8) inside a lever (31L, 31R) pivotally supported by a fixed base (25) via a fulcrum pin (30) and a lever (31L, 31R). Driven cam (31
a), a driving cam (34b) that moves by the opening operation of the main molds (11L, 11R) and abuts on the driven cam (31a), and a slide core (28L, 28R) provided on the lever (31L, 31R). ), A driving unit (31b) connected to
The driving cam (34b) moved by the opening operation of the main mold (11L, 11R) is brought into contact with the driven cam (31a) to swing the lever (31L, 31R) around the fulcrum pin (30), A mold apparatus characterized in that a slide core (28L, 28R) is moved in a mold release direction by a drive section (31b) of a lever (31L, 31R). 2. A return driven cam (31c) is provided on a lever (31L, 31R), and a return drive cam (12a) that is moved by a closing operation of a main mold (11L, 11R) is connected to the return driven cam (31c). ), The lever (31L, 31R) is swung around the fulcrum pin (30) to return the slide core (28L, 28R) to its original position. Mold equipment.