JP2590529Y2 - Boss structure of intake manifold - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boss structure for mounting an intake manifold mounted on an engine.

[0002]

2. Description of the Related Art Conventionally, an intake manifold attached to an engine of this type is formed by casting an aluminum alloy material, and the casting method is, for example, a gravity casting method or a low pressure casting method. 1 is its intake port 2 as shown in FIG.
Is formed, for example, in a cylindrical shape having a predetermined thickness t, and one or a plurality of bosses 3 are formed on the outer periphery of the intake port 2, for example, on the diameter thereof. It is formed into a shape larger than t, and a mounting screw portion 5 is screwed from the end face 4 side.

The mold 6 of the intake manifold 1
As shown in FIG. 4, the upper and lower dies 7 and 8 are formed with upper and lower dies 7 and 8, respectively. At the same time, boss forming recesses 7b and 8b are continuously formed at predetermined positions of the two forming recesses 7a and 8a to form the boss portion 3, so that forming surfaces are formed. As shown, a core mold 10 formed by a sand mold corresponding to the inner diameter portion 2a of the intake port 2 is accommodated in the molding recesses 7a and 8a, and a molten metal of an aluminum alloy material is gravity-cast in the molds 7 and 8. After cooling, the molded product of the intake manifold 1 is taken out, the core 10 is scraped off to form a molded product having an inner diameter portion 2a, and the boss portion 3 is machined. Boss part Mounting thread 5 has been screwed in.

[0004]

However, in the case of casting of the manifold 1, since the volume of the boss 3 formed in the intake port 2 is larger than the thickness t of the intake port 2, the cooling of the boss 3 is performed. In addition to the fact that the base 3a of the boss 3 is in contact with the core 10 in addition to the fact that the base 3a of the boss 3 Therefore, when the mounting screw portion 5 is machined on the boss portion 3, there is a problem that a pressure leak in the port 2 from the shrinkage cavity 11 occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is possible to eliminate casting defects such as shrinkage cavities generated at the base of the boss portion and secure the strength as the boss portion. An object of the present invention is to provide a boss structure of an intake manifold that can perform a service.

[0006]

According to the present invention, in order to solve the above-mentioned technical problems, in forming an intake manifold, a port forming concave portion and a boss forming portion of a lower mold forming surface of a mating mold composed of upper and lower molds. A dam portion serving as a cast-out portion is provided between the concave portion and a rib forming concave portion is provided between the port forming concave portion and the boss forming concave portion on the upper mold forming surface side corresponding to the dam portion, and the intake manifold is provided. The configuration is such that the concave portion and the rib are formed corresponding to the base of the boss portion.

[0007]

With the above construction, the contact area between the boss portion and the mold on the base side is increased, and the cooling rate at the time of cooling is accelerated to approximately the same level as each casting shape portion. The cause of occurrence can be eliminated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a molding die 16 of an intake manifold 21. The molding die 16 has a lower die 17 and a lower die 17 as in the prior art. Port forming recesses 17a... For forming the outer peripheral portion of the intake port 22 of the manifold 21 are formed in the mating surface 19 with the mold 18 as in the conventional case. 1
8a are recessed, and boss forming recesses 17b, 18b are continuously formed at predetermined positions of the both forming recesses 17a, 18a to form the boss portion 23, and forming surfaces are formed respectively. A convex dam portion 20 is formed on the boss forming concave portion 18b of the mold 18 on the port forming concave portion 18a side.

The side surface 20a of the port forming recess 18a of the weir 20 is formed in an arc shape that is continuous with the arc surface of the port forming recess 18a, and the top surface 20b of the weir 20 is substantially aligned with the mating surface 19. The boss forming recess 18b of the lower die 18 is formed by the weir portion 20 into the port forming recess 1.
8a. A rib forming recess 17c having a substantially triangular predetermined width as shown in the drawing is provided at a portion corresponding to the center of the boss forming recess 17b between the port forming recess 17a and the boss forming recess 17b of the upper mold 17. Is recessed.

The upper and lower dies 17, 18 thus formed
The core mold 10 is housed in the port forming recesses 17a and 18a in the same manner as in the prior art and is matched with each other. In addition, a molten metal of an aluminum alloy material is injected to form the intake manifold 21. And after cooling, take out the core 1
0, the intake port 22 having a predetermined thickness t having an inner diameter portion 22a as in the prior art as shown in FIG.
Are formed in the base portion 23a of the boss portion 23 by the weir portion 20, and a rib 24 is formed in the corresponding base portion 23a in the upper part of the figure.

As described above, the intake manifold 2 of this embodiment is
In the first molding, the port forming recess 18 of the lower mold 18 is formed.
between the a and the boss forming concave portion 18b (a cast portion)
During the casting, the boss 23 is cooled by the weir 20 formed in the lower mold 18 so that the wall thickness t of the intake port 22 and the boss 23 are cooled.
The base 23a has a small change in volume due to the formation of the concave portion 23b by the dam portion 20, and the contact surface with the lower mold 18 is increased by the dam portion 20 to increase the cooling rate. Thus, it is possible to prevent the shrinkage cavity 11 of the conventional casting defect from occurring, and the strength of the base portion 23a of the boss portion 23 is ensured since the rib 24 is formed on the side corresponding to the concave portion 23b. In addition, since the shrinkage cavities 11 do not intervene, pressure leakage from the intake port 22 can be eliminated even if the mounting screw portion 5 is formed.

[0012]

According to the present invention, in forming the intake manifold, a dam portion serving as a cast-out portion is provided between the port forming concave portion and the boss forming concave portion of the lower die. At the time of molding, the cooling of the boss portion is performed by the weir portion formed in the lower mold, and the thickness of the intake port and the base of the boss portion are reduced in volume by forming a concave portion by the same weir portion. However, since the contact surface with the lower mold is increased by the weir portion and the cooling rate is increased, the occurrence of shrinkage cavities of the conventional casting defect can be prevented. Since the ribs are formed, the strength of the base of the boss portion can be ensured, and since there is no shrinkage cavity, pressure leakage from the intake port can be eliminated even if the mounting screw portion is formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mold for an intake manifold.

FIG. 2 is a cross-sectional view of an intake manifold.

FIG. 3 is a cross-sectional view of a conventional intake manifold.

FIG. 4 is a cross-sectional view of a conventional mold for an intake manifold.

[Explanation of symbols]

 16 Mold 17, 18 Mold 17 a, 18 a Port forming recess 17 b, 18 b Boss forming recess 17 c Rib forming recess 20 Weir 21 Intake manifold 22 Intake port 23 Boss 23 a Base 23 b Recess 24 Rib

Continuation of front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F02M 35/104 B22C 9/24

Claims (1)

(57) [Scope of request for utility model registration] In the molding of an intake manifold, a dam portion serving as a cast-out portion is provided between a port molding concave portion and a boss molding concave portion of a lower mold molding surface of a lower mold formed by upper and lower molds. A rib forming recess is provided between the port forming recess and the boss forming recess on the upper mold forming surface corresponding to the weir portion, and the recess and the rib are formed corresponding to the base of the boss of the intake manifold. Intake manifold boss structure.