JP3400397B2 - Mold equipment - Google Patents

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 molds that are opened and closed so as to approach and separate from each other to cast a product, and a slide core movable in a direction different from the opening and closing direction of the main molds. The present invention relates to a mold device that is arranged and molds a recess inside a product with this 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 a gravity casting method, a recess inside the product is formed by using a slide core. The slide core arranged parallel to the opening / closing direction of the main mold does not require a special drive source for pulling out to move back and forth together with the main mold, but is arranged inclined with respect to the opening / 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 to give the slide core a predetermined draft. If a large draft can be secured, the slide core can be released from the product with a relatively small driving force, but if the draft cannot be secured due to the design requirements of the recess, the slide core is driven. As a driving source for driving, a large output is required, which causes a problem of increasing the size and cost of the mold device.

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

[0005]

In order to achieve the above-mentioned object, according to the invention described in claim 1, mutual access and
Inside a pair of main molds that open and close so as to separate from each other to cast a product, a slide core that is movable in a direction different from the opening and closing direction of the main molds is arranged, and a recess is formed inside the product with this slide core. In the mold device, a lever pivotally supported by a fixed base via a fulcrum pin, a driven cam provided on the lever, a drive cam that moves by the opening operation of the main mold and contacts the driven cam, and a lever. A drive cam connected to the slide core, the drive cam moving by the opening operation of the main mold is brought into contact with the driven cam to swing the lever around the fulcrum pin, and the lever drive unit slides the slide core. A mold apparatus is proposed which is characterized in that the mold is moved in the releasing direction.

According to the above construction, when the main mold is closed and the product is cast and then the main mold is opened, the drive cam which is 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 part of the lever moves in the releasing direction. As a result, even when it is difficult to release the slide core due to the small draft, the slide core is forcibly moved in the release direction in association with the opening operation of the main die, which enables reliable release. This makes it possible to reduce the draft and increase the degree of freedom in designing the shape of the end face and the wall surface of the recess. Moreover, since no special drive source is required to move the slide core, it is possible to contribute to the reduction of the number of parts and cost.

Further, according to the invention described in claim 2,
In addition to the structure of claim 1, the lever is provided with a return driven cam, and the return drive cam that is moved by the closing operation of the main mold is brought into contact with the return driven cam to swing the lever around the fulcrum pin. A mold apparatus is proposed which is characterized by moving the slide core to return it to its original position.

According to the above construction, 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, so that the slide core connected to the lever is automatically moved to the original position. As a result, the special drive source for returning the slide core to the original position is unnecessary.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.

1 to 18 show an embodiment of the present invention. FIG. 1 is a bottom view of a piston for an internal combustion engine, and FIG. 2 is FIG.
2-2 line sectional view, FIG. 3 is a vertical 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 taken in the direction of arrow 5 in FIG. 3, FIG. 6 is a sectional view taken along line 6-6 of FIG. 3, and FIG. 7 is an enlarged view of part 7 in FIG. 8 is a sectional view taken along line 8-8 of FIG. 3, and FIG. 9 is FIG.
9 is a sectional view taken along line 9-9, 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, and FIG.
12 is a sectional view taken along line 12-12, FIG. 13 is a sectional view taken along line 13-13 of FIG. 12, and FIG. 14 is an operation explanatory view corresponding to FIG.
~ FIG. 18 is a piston casting process diagram.

FIG. 1 and FIG. 2 show a piston P for an internal combustion engine before being machined as it is taken out from a gravity casting mold. The piston P has a cylindrical shape which is continuous with a circular top surface 1 below. The ring land portion 2 and a pair of skirt portions 3, 3 extending downward from both ends of the ring land portion 2 in the diameter direction.
And a pair of wall portions 4, which connect the pair of skirt portions 3, 3.
4, a bag-shaped space 5 surrounded by the skirts 3 and 3 and the walls 4 and 4, a pair of bosses 7 provided in the walls 4 and 4 and through which the piston pin holes 6 and 6 penetrate. 7, and a pair of recesses 8 and 8 for lightening is formed between the ring land portion 2 and the boss portions 7 and 7. The end surfaces 7a, 7a of the boss portions 7, 7 facing the recesses 8, 8 are parallel or slightly inclined with respect to the 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 the gravity casting mold will be described with reference to FIGS. The mold for gravity casting is the piston P
It has a bilaterally symmetrical structure with respect to the center plane C.

The gravity casting mold has two left and right sides with a center plane C interposed therebetween.
A pair of divided main molds 11L and 11R is provided. Main mold 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. The left and right main mold holders 12L and 12R respectively have four bolts Ba,
It is fixed by Ba and opened and closed in the left-right direction by a drive source (not shown) (see FIG. 5). The left and right main molds 11L and 11R have two bolts Bb and B, respectively, provided with cast pin guides 13L and 13R.
It is fixed by b and these cast pin guides 13L,
On 13R, casting pins 14L and 14R for casting the piston pin holes 6 and 6 on the boss portions 7 and 7 of the piston P are slidably supported. The casting pins 14L and 14R slide in the left-right direction relative to the casting pin guides 13L and 13R by a drive source (not shown). The disk-shaped top core 15 that can be moved up and down by a drive source (not shown) is a closed left and right main mold 11.
The top surface 1 which is fitted to the upper surface opening of L and 11R and extends above the ring land portion 2 of the piston P is formed.

A bag-shaped space 5 having an open lower surface surrounded by the skirts 3, 3 and walls 4, 4 of the piston P has a pair of side cores 16L, 16R and both side cores 16L, 1L.
It is molded by the center core 17 sandwiched by 6R. The left and right side cores 16L and 16R are fixed to the side core holders 18L and 18R with bolts Bc and Bc, respectively, and are opened and closed in the left and right directions by a drive source (not shown). Corresponding to the boss portions 7, 7 of the piston P, the side core 16
Undercut portions 16a, 16a on the outer surface of L, 16R
(See FIG. 7) is formed.

As is apparent from FIGS. 12 and 13,
The center core 17 includes an inner member 19, a pair of outer members 20 arranged on both front and rear sides of the inner member 19,
And 20. The inner member 19 fixed by the 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-back direction (direction orthogonal to the paper surface of FIG. 4).
Of the tapered surfaces 19a, 19 whose width becomes narrower upward
a, and a pair of front and rear outer members 20, 20 are provided on the tapered surfaces 19a, 19a to engage with dovetail grooves 19b, 19a.
It is slidably supported by b (see FIG. 13).

At the lower ends of the front and rear outer members 20, 20, guide pins 22 parallel to the tapered surfaces 19a, 19a,
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 biased upward by springs 24, 24. It Guide pin 2
Flange-shaped stopper 2 formed in the intermediate portion of 2, 22
2a and 22a function as seats for the springs 24 and 24, and regulate the maximum sliding amount of the outer members 20 and 20 with respect to the inner member 19. Undercut portions 20a, 20a having a reduced width in the front-rear direction are formed on 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 attached to a pair of front and rear mold ring holders 27, 27 fastened to the fixed base 25 with a total of four bolts Be. It is pressed and fixed (see FIG. 6). Mold ring 26,
A pair of left and right slide cores 28L, 28 is provided in the space sandwiched between the main molds 11L, 11R and the side cores 16L, 16R.
R is placed. The slide cores 28L and 28R are for molding the recesses 8 and 8 (see FIG. 2) for thinning the outside of the wall portions 4 and 4 of the piston P, and the end surfaces 7a and 7a of the boss portions 7 and 7 are It is provided with end faces 28a, 28a to be molded.

During mold clamping, the outer surfaces of the slide cores 28L and 28R are in close contact with the inner surfaces of the main molds 11L and 11R, and the side walls 4 of the piston P are provided between the inner surfaces of the slide cores 28L and 28R and the outer surfaces of the side cores 16L and 16R. A cavity for molding 4 and the boss portions 7, 7 is defined. In addition, the positioning portion 1 of the casting pins 14L and 14R inclined from 0 ° to 5 °
4a and 14a penetrate the pin fitting holes 28b and 28b of the slide cores 28L and 28R, and the taper portions 14b and
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 is apparent from 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 with bolts Bf, Bf, respectively. Between the two fulcrum pin holders 29, 29 forming the fulcrum pin 30, 3
The intermediate portion of the levers 31L and 31R is pivotally supported at 0. The inner ends of the levers 31L and 31R are molded rings 2
6 and the openings 32, 32 (see FIG. 10) formed on the left and right side surfaces of the main molds 11L, 11R and extend through 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 positioned on the front and rear sides of the pair of fulcrum pin holders 29, 29. A pair of guide keys 33,
Horizontal guide surfaces 33a, 33a are formed on the upper surface of 33, and these guide surfaces 33a, 33a are the main mold 11L,
It is possible to abut on the guide surfaces 11a, 11a formed on the lower surface of 11R.

Ejector blocks 34, 34 formed in a U shape are respectively formed on the inner surfaces of the main mold holders 12L, 12R facing the outer surfaces of the main molds 11L, 11R with bolts Bh, Bh.
Is fixed (see FIGS. 7 and 11). Inclined drive cams 34b, 34b are formed on the upper surfaces of the central portions of the ejector blocks 34, 34, and these driven cams 34b, 34b are inclined driven cams 31a, 31a formed on the lower surfaces of the outer ends of the levers 31L, 31R. Can abut.

As apparent from FIGS. 7 and 9, the mold ring 26 is formed on the lower surface of the slide cores 28L and 28R.
The links 35, 35 are supported by two bolts Bi, Bi on each of the left and right that loosely penetrate through the mold ring 26.
The washers 36, 36 are supported by one bolt Bj on each of the left and right and a collar 37 that loosely penetrates. Then, drive portions 31b, 31b provided at the inner ends of the left and right levers 31L, 31R
Are the links 35, 35 and washers 36, 3 respectively.
Fit between 6

As is apparent from FIG. 7, the levers 31L,
Returning driven cams 31c, 3 inclined to the upper surface of the outer end of 31R
1c is formed, and the return driven cams 31c, 3c
Returning 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 gravity casting mold in the mold clamped state, the left and right main molds 11L and 11R for molding the ring land portion 2 and the skirt portions 3 and 3 of the piston P come close to each other and fit on the outer peripheral surface of the mold ring 26. Together with the top core 15 for molding the top surface 1 of the piston P
Goes down and fits into the upper openings of the main molds 11L and 11R.

The left and right side cores 16L and 16R and the center core 17, which form the space 5 in the piston P, are located at the ascending end with their upper ends flush with each other. The slide cores 28L and 28R that form the recesses 8 and 8 on the outside of the wall portions 4 and 4 of the piston P are in the raised position, and the pin insertion holes 28b and 28b have cast-out pins 14L and 14L.
The R positioning portions 14a, 14a are closely fitted and positioned.

Subsequently, as shown in FIG. 15B, the top core 15 is lifted to separate the top surface 1 of the piston P from the mold, and then, as shown in FIGS. 4 and 16C, first. The casting pins 14L, 14R are pulled out from the main molds 11L, 11R in the left-right direction to separate the piston pin holes 6, 6 of the boss portions 7, 7 of the piston P from the molds, and then the main molds 11L,
11R is opened to the left and right to separate the ring land portion 2 and the skirt portions 3, 3 of the piston P from each other.

Along with the movement of the main molds 11L, 11R in the left-right direction, the main mold holder 12 integrated with the main molds 11L, 11R.
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 around, and the drive portions 31b, 31b at the inner ends thereof descend. As a result, the drive portions 31b of the levers 31L and 31R,
Slide core 2 in which links 35, 35 are pressed by 31b
8L and 28R are lowered by the gap δ (see FIG. 7), and the end surfaces 28a and 28a of the slide cores 28L and 28R are moved to the recesses 8 and 8 of the piston P and the end surfaces 7a and 7a of the boss portions 7 and 7, respectively.
(See FIG. 2)

Bosses 7 facing the recesses 8 of the piston P,
Since the end surfaces 7a, 7a of 7 and the end surfaces 4a, 4a of the wall portion 4 (see FIG. 2) have an extremely small draft, these end surfaces 7a, 7a
a, 7a; slide core 28L for molding 4a, 4a,
Although it becomes difficult to separate the end faces 28a, 28a of 28R from the mold,
In this embodiment, the slide cores 28L, 31L, 31R are moved by the levers 31L, 31R as the main molds 11L, 11R move in the left-right direction.
Since 28R is forcibly lowered in a direction away from the center plane C of the piston P (see arrow A in FIG. 7), the end surfaces 7a, 7a of the boss portions 7, 7 of the piston P and the end surface 4a of the wall portion 4, 4a to end surfaces 2 of slide cores 28L and 28R
8a and 28a can be reliably released from the mold. Moreover, the slide cores 28L and 28R are lowered by the main molds 11L and 1L.
Since it is automatically performed in conjunction with the 1R left-right mold opening, no special drive source is required.

Subsequently, FIG. 12, FIG. 14 and FIG.
As shown in (d), with the ring land portion 2 of the piston P chucked, the left and right side cores 16L, 1
The inner member 19 of the center core 17 sandwiched by 6R is lowered together with the center core holder 21. Even if the inner member 19 of the center core 17 descends, the outer members 20, 20 that are urged upward by the springs 24, 24 and the guide pins 22, 22 do not immediately descend,
Initially it is kept at its original height. Therefore, the outer member 2
When the inner member 19 moves down relative to the inner surface 0 and the inner surface 19, the tapered surfaces 19a, 1
Outer member 2 engaging dovetail groove engagement 19b, 19b with 9a
0 and 20 move toward each other, and the undercut portions 20a and 20a are separated from the inner wall surface of the space portion 5 of the piston P.

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

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 portion 5 of the piston P, and then, as shown in FIG. 17 (f). As shown in FIG.
While avoiding the undercut portion 16a of L from interfering with the boss portion 7 of the piston P, the left side core 16L is pulled out and separated from the space portion 5.

Further, as shown in FIG. 18 (g), the right side core 16R is moved leftward together with the side core holder 18R to separate it from the space portion 5 of the piston P, and then to FIG. 18 (h). As shown, by pulling 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 of the above. The main mold holders 12L, 1 together with the left and right main molds 11L, 11R during the mold clamping process.
When 2R moves in the closing direction, the main mold holders 12L, 12
The return drive cams 12a, 12a provided on the R
Returning driven cam 31 provided on the upper surface of the outer end of 1L, 31R
The levers 31L and 31R are swung around the fulcrum pins 30 and 30 from the position indicated by the chain line in FIG. 7 to the position indicated by the solid line in FIG. As a result, the drive unit 31 of the levers 31L and 31R
b and 31b rise to raise the slide cores 28L and 28R to their original positions. In this way, the slide cores 28L and 28R are automatically returned to their original positions in accordance with the closing operation of the main molds 11L and 11R, so that a special drive source is not required and the number of parts and the cost can be reduced. .

Although the embodiments of the present invention have been described in detail above, the present invention can be modified in various ways without departing from the scope of the invention.

For example, the piston P for an internal combustion engine is illustrated as a product in the embodiment, but the present invention is not limited to the slide core 28.
It can be applied to any product having the recesses 8 and 8 formed by L and 28R. Further, in the embodiment, the levers 31L and 3 whose central portion is pivotally supported by the fulcrum pins 30 and 30 are used.
The driven cams 31a and 31a and the drive unit 3 are provided at both ends of 1R.
Although 1b and 31b are provided, the positional relationship among the fulcrum pins 30 and 30, the driven cams 31a and 31a, and the drive units 31b and 31b can be changed as appropriate.

[0037]

As described above, according to the invention described in claim 1, when the main mold is opened after the main mold is clamped and the product is cast, the drive cam is moved by the opening operation of the main mold. Contacts the driven cam of the lever and swings the lever around the fulcrum pin, so that the slide core connected to the drive portion of the lever moves in the releasing direction. As a result, even when it is difficult to release the slide core due to the small draft, the slide core is forcibly moved in the release direction in association with the opening operation of the main die, which enables reliable release. This makes it possible to reduce the draft and increase the degree of freedom in designing the shape of the end face and the wall surface of the recess. Moreover, since no special drive source is required to move the slide core, it is possible to contribute to the reduction of 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, the lever swings around the fulcrum, and the slide core connected to the lever automatically returns to its original position. A special drive source for returning to the position is unnecessary.

[Brief description of drawings]

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

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

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

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

5 is a view in the direction of arrow 5 in FIG.

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

7 is an enlarged view of part 7 in FIG.

8 is a sectional view taken along line 8-8 of FIG.

9 is a sectional view taken along line 9-9 of FIG.

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

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

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

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

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

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 the piston casting process diagram.

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

[Explanation of symbols]

P piston (product) 8 recess 11L main mold 11R main type 12a Drive cam for return 25 Fixed part 28L slide core 28R slide core 30 fulcrum pin 31L lever 31R lever 31a driven cam 31b drive unit 31c Driven cam for return 34b drive cam

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B22C 9/06 B22D 17/22

Claims (2)

(57) [Claims] 1. A direction different from the opening / closing direction of the main molds (11L, 11R) inside a pair of main molds (11L, 11R) for opening and closing so as to approach and separate from each other and casting the product (P). A movable slide core (28L, 28R) is placed on the slide core, and the product (P) is produced with this slide core (28L, 28R).
In a mold device for molding 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) are provided. Driven cam (31
a), a drive cam (34b) that moves by the opening operation of the main molds (11L, 11R) and contacts the driven cam (31a), and slide cores (28L, 28R) provided on the levers (31L, 31R). ) Connected to the drive unit (31b),
A drive cam (34b) that moves 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, wherein a slide core (28L, 28R) is moved in a releasing direction by a drive portion (31b) of a lever (31L, 31R). 2. A recovery driven cam (31c) is provided on the lever (31L, 31R), and a recovery drive cam (12a) that moves by the closing operation of the main molds (11L, 11R) is replaced by the recovery driven cam (31c). ), The lever (31L, 31R) is swung around the fulcrum pin (30) to return the slide core (28L, 28R) to the original position. Mold equipment.