JP2990996B2 - Cylinder head casting 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 casting apparatus capable of improving the dimensional accuracy of a cylinder head casting in casting a cylinder head.

[0002]

2. Description of the Related Art When mass-producing automobile parts and the like, low pressure casting is widely used. With this low-pressure casting method, a mold is placed on a closed furnace containing a molten metal (molten metal), the closed furnace and the mold are connected by a conduit (Stoke), and a slight pressure is applied inside the furnace. Casting is performed by ascending in the stalk against gravity and being injected into a mold cavity from a lower gate of a mold attached to an upper portion of the stalk. This low pressure casting method is often applied to aluminum-based light alloy castings, and cylinder heads are also generally cast using low pressure casting.

[0003] For example, Japanese Patent Application Laid-Open No. 64-53775 discloses a low-pressure casting method for the cylinder head.
FIG. 7 shows a cylinder head casting apparatus used in JP-A-64-53775. In FIG. 7, reference numeral 30 indicates a casting apparatus main body. The casting mold 32 constituting the casting apparatus 30 includes a lower mold 34, an upper mold 36 and a horizontal mold 3
8a, 38b and 40a, 40b. The lower mold 34, the upper mold 36 and the horizontal molds 38a, 38a,
8b and 40a, 40b define a cavity 42. The nozzle 46 is connected to a stalk 47 for feeding the molten metal to the cavity 42, and the stalk 47 is provided in a not-shown insulated furnace installed below the lower mold 34 and in a crucible in which the molten metal is stored. It is inserted. Cooling hole 48
Extends into the nest 49.

[0004] Further, as will be understood from the drawing, of the components of the cylinder head in the cavity 42,
In order to promote cooling of a relatively thick portion having a hole through which the valve guide is inserted, cast members (cooling members) 54a and 54b having a cooling mechanism are provided on the movable die base 50, It is inserted into holes 56a and 56b penetrating the mold 36. Here, the cast members (cooling members) 54a, 5a
4b does not come into contact with the cores 80b and 80c for forming the intake path and the exhaust path of the cylinder head.

[0005] The cores 80b and 80c form an exhaust path and an intake path of the cylinder head.
80d to 80f are for forming a water jacket through which cooling water flows. Cores 80b and 80c for forming an exhaust path and an intake path of a cylinder head
Are fitted into the horizontal dies 38a, 38b, 40a, and 40b, respectively, and are further in contact with the nest 49.

[0006]

However, in the conventional cylinder head casting apparatus, when the molten metal flows into the cavity, the clearance between the core and the mold fluctuates due to the flow pressure due to the flow of the molten metal, and the position of the core is changed. Because it shifts,
It has been difficult to maintain stable dimensional accuracy of the cylinder head casting. FIG. 6 shows an example in which the cores 80b and 80c for forming the intake path and the exhaust path of the cylinder head are displaced when the molten metal flows in (the cast member of the valve guide is omitted in the figure). Is). The positions of the cores 80b and 80c before the inflow of the molten metal are indicated by solid lines 10 and 11, and the positions of the cores 80b and 80c after the inflow of the molten metal are indicated by dashed lines 12 and 13.
Shown in As can be understood from FIG. 6, the displacement of the core due to the flow pressure of the molten metal when the molten metal flows into the cavity causes the center 14 around the core for forming the intake path and the exhaust path of the cylinder head to be particularly formed (indicated by a solid line). In the area surrounded by the above, the variation in the thickness becomes large.

The present invention has been made in view of such circumstances, and in a core for forming an intake path and an exhaust path of a cylinder head, an inner end for forming the intake path and the exhaust path of the core. The dimensional accuracy of the cylinder head cast product is improved by restricting the core movement between the portions by contacting the portion with both the mold and the valve guide cast-out portion that is a part of the mold. With the goal.

[0008]

SUMMARY OF THE INVENTION A cylinder head casting apparatus according to the present invention includes a mold for casting a cylinder head, the mold including a partial mold having a valve guide blanking portion and another partial mold. In a cylinder head casting apparatus comprising a core for forming an intake path and an exhaust path, and an outer end of the core is fitted or held in the mold, an inner end of the core is formed by the valve guide casting. It is characterized in that it is sandwiched by both a partial mold having a punched portion and another partial mold.

[0009]

According to the cylinder head casting apparatus of the present invention, a mold for casting a cylinder head, comprising a partial mold having a valve guide cast-out portion and another partial mold, and an intake passage and an exhaust passage of the cylinder head. An outer end of the core (hereinafter, referred to as a core outer end) is fitted or held in the mold. Furthermore, the inner end of the core (hereinafter, referred to as the core inner end) is sandwiched by both the partial mold having the valve guide cast-out portion and the other partial molds. As a result, when the molten metal flows into the mold, the core receives the flowing pressure of the molten metal, but the inner end of the core is pressed by the contact portions of both the partial mold having the valve guide cast-out portion and the other partial molds. The movement of the core inner end is restricted between the parts, and the movement of the core outer end is also restricted because the core outer end is sandwiched or fitted into the mold, thereby preventing displacement of the core. be able to.

[0010]

【Example】

(First Embodiment) FIG. 1 shows a partial sectional view of a cylinder head casting apparatus 6 according to a first embodiment of the present invention. The cylinder head casting device 6 is generally constituted by a mold for casting the cylinder head and a core for molding the cylinder head. The mold for casting the cylinder head is a partial mold, a valve guide cast-out member having an upper mold 1, a lower mold 2, a horizontal mold 3, and a valve guide cast-out portion for forming a hole through which the valve guide is inserted. 7 and 8. The core for forming the cylinder head is a core 9 for forming the exhaust path and the intake path of the cylinder head.
0 and 91 and cores 5c to 5f for forming a water jacket through which cooling water flows. The core outer end 90b of the core 90 for forming the exhaust path of the cylinder head is sandwiched between the lower mold 2 and the horizontal mold 3, and the core 91 of the core 91 for forming the intake path of the cylinder head. The outer end portion 91b is sandwiched between the upper die 1 and the lower die 2 (a portion of the lower die 2 corresponding to the core outer end portion 91b is not shown in the drawing).

The lower mold 2 abuts the inner ends 90a, 91a of the cylinder head at the abutments 2a, 2b, respectively.

The upper die 1 has a valve guide cast-out member 7 having cast-out portions 20 and 21 (hereinafter, referred to as a valve guide cast-out portion) for forming a valve guide insertion passage portion.
8 (hereinafter referred to as cast members 7, 8) penetrate,
It protrudes into the cavity 9. The cast members 7 and 8 are detachable from the upper die 1. The cast member 7 is a cast member 7.
The stepped portion 7a of the upper die 1
And the stepped portion 8a of the cast member 8 abuts on the upper die 1 to position the cast member 8.

Further, the cast-out portion 20, which is the tip of the cast-out member 7, abuts against the contact portion 7b against the core inner end portion 90a. Similarly, the cast-out portion 21 which is the tip of the cast-out member 8
Abuts against the contact portion 8b against the core inner end portion 91a.
Abutting refers to a state in which the inner core ends 90a and 91a are pressed with a pressing force that does not damage the inner core ends 90a and 91a. Therefore, the core inner end 90a is
It is sandwiched by both the valve guide cast-out portion 20 and the lower mold 2, and is restricted from moving between the contact portions 7b and 2a (in this case, the vertical movement in the drawing). For this reason,
When the molten metal flows into the cavity, even if the core inner ends 90a and 91a receive a vertical force in the drawing due to the flow pressure of the molten metal flowing from below the drawing, the drawing between the drawing portions by the contact portions 7b and 2a. By restricting the movement of the core in the vertical direction, it is possible to prevent the core from shifting in the vertical direction in the drawing.

The valve guide blanking portions 20, 21 which are the tip portions of the blanking members 7, 8 are provided with machining allowances for the actual product insertion passage shapes (shown by broken lines in the drawing) 22, 23. The dimensions are used.

After the molten metal is injected into the cavity 9 using the above-described apparatus and the casting is completed, first, the cast members 7 and 8 are cast.
After the mold is separated from the cylinder head casting, the upper mold 1, the lower mold 2 and the horizontal mold 3 are separated from each other in the directions indicated by arrows 24 and 25 by a separate drive before the product is released from the casting.

Also, the cast members 7, 8 may be provided with a cooling mechanism for promoting cooling of a relatively thick portion where a hole for inserting the valve guide is formed. good. For example, a space may be provided inside the cast members 7 and 8 and the space may be filled with a cooling medium.

(Second Embodiment) FIG. 2 is a partial sectional view of a cylinder head casting apparatus 6 according to a second embodiment of the present invention.
As shown in FIG. 2, the difference from the first embodiment is that the molds for casting the cylinder head are partial molds, ie, upper mold 1, lower mold 2, horizontal mold 3, cast members 7, 8 and insert 4. , And the core inner end portion 90a,
It goes without saying that the same effect as in the first embodiment can be obtained even if the boss 91a hits the nest 4. in this case,
The core inner end portions 90a and 91a are cast members 7,
8 and the nest 4. The core outer end portion 91b of the cylinder head is sandwiched between the upper die 1 and the lower die 2 (in the figure, a portion of the lower die 2 corresponding to the core outer end portion 91b is not shown).

(Third Embodiment) FIG. 3 shows a partial sectional view of a cylinder head casting apparatus 6 according to a third embodiment of the present invention.
As shown in FIG. 3, the difference from the first and second embodiments is that the cast-out members 7, 8 as partial molds do not penetrate the upper mold as partial molds. In this case, after the cylinder head is cast, the movement of the mold when removing the cylinder head casting from the mold is as follows. First, the upper die is moved upward in the drawing, and then the cylinder head casting (the cavity 9 in the figure) is moved.
In which the molten metal has been injected into the cylinder and the hardened shape) is removed from the cylinder head casting. The core outer end portion 91b of the cylinder head is sandwiched between the upper die 1 and the lower die 2 (in the figure, a portion of the lower die 2 corresponding to the core outer end portion 91b is not shown). In the third embodiment, the same operation and effect as in the first embodiment can be obtained.

(Fourth Embodiment) FIG. 4 is a partial sectional view of a cylinder head casting apparatus 6 according to a fourth embodiment of the present invention.
As shown in FIG. 4, the difference from the first to third embodiments is that the upper mold 1 of the partial mold is
The point is that the structure has b. It goes without saying that, depending on the product shape, the upper die 1 may have a structure having a valve guide cast-out portion for forming the valve guide insertion passage. In this case, it becomes possible when the removal direction of the upper mold 1 and the valve guide cast-out portions 20 and 21 are in a parallel relationship. Core outer end 91b of cylinder head
Is sandwiched between the upper mold 1 and the lower mold 2 (in the figure, the lower mold 2
Of the inner core end 91b is not shown. ).

(Fifth Embodiment) FIG. 5 is a partial sectional view of a cylinder head casting apparatus according to a fifth embodiment of the present invention. The fifth embodiment is different from the first to fourth embodiments in that the fifth embodiment has the structure of the partial die-cut members 7, 8 and the cores 90, 91. FIG. 5 shows only the structure of the leading end of the cast member 7 and the inner core end 90a. A cast-out member 8 and a core inner end portion 91 (not shown) corresponding to the first embodiment.
The structure of “a” is the same as the structure of the distal end portion of the cast member 7 and the core inner end portion 90a shown in the figure. Here, the cast-out member 7 has penetrated the through-hole 5a of the core inner end part 90a. The position of the cast member 7 is determined by the tip 7d of the cast member 7 abutting against the insert 4.

At this time, a stepped portion 7c is formed at the boundary between the portion 15 of the cast member 7 where the valve guide cast hole is formed and the core insertion portion 16 inserted into the through hole 5a of the core. Is formed. The core insertion portion 16 has a tapered shape. The stepped portion 7c of the cast-out member 7 has a contact portion 7 with the core.
e, and the core insertion portion 16 further abuts on the inner core portion 90a and the abutment portion 5b. Here, the core inner end portion 90a abuts on the insert 4 and the contact portion 4a. As a result, the inner core portion 90 a is sandwiched by both the stepped portion 7 c of the cast member 7 and the insert 4. As described above, the inner core end 90a is moved between the abutments 7e, 5b, and 4a by the abutments 7e, 5b, and 4a (in the vertical and horizontal directions in the drawing and in the direction perpendicular to the plane of the drawing). , The occurrence of core displacement can be prevented regardless of the flow direction of the molten metal.

In the fifth embodiment, the tip 7d of the cast member 7 is used.
The abutment with the nest 4 positions the cast-out member 7, so that the dimensional accuracy of the core against the lower mold and the nest, which is a dimensional reference, is reduced against the influence of mold warpage due to the heat of the molten metal. It is further improved. Assuming that the width of the dimensional deviation (deviation with respect to the product standard on the drawing) of the cast product obtained by using the apparatus of Example 2 is ± 1.0, the width of the cast product obtained by using the apparatus of Example 5 is ± 1.0. Dimensional deviation width is ± 0.
Within 5

The valve guide cast-out portion 20, which is the leading end of the cast-out member 7, has a dimension in which a machining allowance is provided for an actual product insertion passage shape (shown by a broken line in the drawing) 22.

After the molten metal is injected into the cavity 9 using the above-described apparatus and the casting is completed, first, the cast members 7 and 8 are cast.
Before the mold is removed from the cylinder, the upper mold 1, the lower mold 2 and the horizontal mold 3 are separated from the cylinder head casting after the casting is separated by another drive in the arrow direction 27.

Also here, of course, the cast members 7, 8
Needless to say, the device may be provided with a cooling mechanism for promoting cooling of a relatively thin portion where the hole through which the valve guide is inserted is formed. For example, a space may be provided inside the cast members 7 and 8 and the space may be filled with a cooling medium.

[0026]

According to the present invention, a mold composed of a partial mold having a valve guide cast-out portion and another partial mold for casting a cylinder head, and an intake path and an exhaust path of the cylinder head are formed. The outer end of the core is fitted or sandwiched in the partial mold, and the inner end of the core is used in both the partial mold having the valve guide cast-out portion and the other partial molds. By restricting the movement of the core by holding the core, the core displacement can be prevented, and a cylinder head casting with good dimensional accuracy can be obtained. In addition, since the thickness variation around the core for forming the intake path and the exhaust path of the cylinder head can be reduced, the product can be made as thin as possible and the weight can be reduced. it can. Furthermore, as various operations to improve the dimensional accuracy, for example, a partial presser seat is provided on a part of the baseboard, and tuning of the convexity of the presser seat is repeated while looking at the cylinder head casting, and Since it is not necessary to perform an operation such as balancing the product dimensional deviation by setting a large value, the dimension can be determined in a short time, the efficiency of production preparation can be improved, and the production cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a cylinder head casting device showing a first embodiment of the present invention.

FIG. 2 is a partial sectional view of a cylinder head casting apparatus showing a second embodiment of the present invention.

FIG. 3 is a partial sectional view of a cylinder head casting apparatus showing a third embodiment of the present invention.

FIG. 4 is a partial sectional view of a cylinder head casting apparatus showing a fourth embodiment of the present invention.

FIG. 5 is a partial sectional view of a cylinder head casting apparatus showing a fifth embodiment of the present invention.

FIG. 6 is a view showing a state of a core displacement when the molten metal flows in.

FIG. 7 is a sectional view of a conventional cylinder head casting apparatus.

[Explanation of symbols]

6... Mold for casting cylinder head 90... Core for forming cylinder head intake passage 91... Core for forming cylinder head intake passage 90 a ····· Inside end forming an intake path in the core 90b ····· Outside end 91a forming an exhaust path in the core ···· Inside end forming the intake path in the core 91b ······ Outer end portion of the core for forming an exhaust path 20 and 21 ··· Valve guide blanking portion

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-249645 (JP, A) JP-A-61-167238 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B22C 9 / 24,9 / 10

Claims (1)

(57) [Claims] 1. A mold for casting a cylinder head, comprising a partial mold having a valve guide cast-out portion and another partial mold, and a core for molding an intake passage and an exhaust passage of the cylinder head. In the cylinder head casting apparatus, wherein the outer end of the core is fitted or sandwiched in the partial mold, the inner end of the core has a partial mold having the valve guide cast-out part and another partial mold. And a cylinder head casting device.