JPH0580302B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for casting an intake manifold for a multi-cylinder engine, and more particularly to a method for casting an intake manifold for a multi-cylinder engine, and in particular for casting a substantially L-shaped intake manifold in which a distribution chamber and an intake duct are integrated. The present invention relates to a method for casting an intake manifold with integrated distribution chamber.

(Prior Art) An intake manifold used in a multi-cylinder engine such as an automobile engine has a distribution chamber for distributing intake air, and an opening for the intake air supplied from the distribution chamber 1 to the side of the cylinder head of the engine body. A plurality of intake conduits are provided for leading to a plurality of intake ports. In the past, these distribution chambers and intake pipes were cast as separate parts, but recently, it has become common to see them being integrally cast, especially as intake manifolds for fuel-injected engines. ing. When installed in the engine body, such an intake manifold typically has a distribution chamber located on the side of the engine body, and an intake conduit extending downwardly from the distribution chamber and extending generally horizontally toward the cylinder head. It is said to be L-shaped, extending to .

By the way, when casting such an intake manifold with an integrated distribution chamber, it is necessary to use a large core with a complicated shape, and the intake manifold of the product is thin and long in shape. Therefore, gravity casting is mainly used to minimize casting defects. In this case, the mold is provided with sprues at several locations, and the mold is tilted as the metal is poured from each sprue.

FIG. 5 is a side view showing an example of an intake manifold integrated with a distribution chamber, which is cast by a conventional method based on such a gravity casting method.

As is clear from this figure, this intake manifold 1 includes an intake pipe 3 on the inner side of the distribution chamber 2.
Sprue marks 5, 6, and 7 are formed on the upper surface side of the intermediate portion and on the mounting surface side of the mounting flange 4, respectively. That is, this intake manifold 1 is formed by holding a mold such that the intake manifold 1 is cast with the intake line 3 extending downwardly from the distribution chamber 2 and then extending substantially horizontally, substantially in the same manner as in its installed state. The mold is poured by pouring the metal from the upper surface side of the middle part of the mold, and by tilting the mold and pouring the metal from the distribution chamber 2 and mounting flange 4 sides respectively.

(Problems to be Solved by the Invention) However, in such a gravity casting method, the tilting angle and time of the mold must be appropriately controlled depending on the direction of pouring. Therefore, in the case where the metal is poured from three directions as described above, it becomes more difficult to control the pouring from three directions. It is sufficient if casting can be performed by pouring the metal only from the distribution chamber 2 and mounting flange 4 side,
A large core is provided in the second part of the distribution chamber,
Since the molten metal is cooled by the core,
The molten metal poured from the distribution chamber 2 side is difficult to flow to the middle part of the intake pipe 3, and casting defects occur in that part.

Furthermore, if sprue marks 5 and 6 remain on the inner surface of the distribution chamber 2 and the upper surface of the middle part of the intake pipe 3,
These will be visible from the outside when the intake manifold 1 is attached to the engine body.
The appearance will be damaged.

The present invention was developed in view of these problems, and its main purpose is to pour metal from fewer directions without causing casting defects.
It is possible to cast an intake manifold with an integrated distribution chamber.

Another object of the present invention is to prevent the sprue marks from being noticeable and to enable the sprue marks to be used for supporting the intake manifold and the like.

(Means for Solving the Problems) In order to achieve this object, the present invention provides an intake manifold that is a product in a state in which it is upside down from the installed state, that is, the intake pipe is directed downward from the horizontal part. The mold is held so that the distribution chamber is cast with the distribution chamber positioned downward, and the flange molding part forms the intake manifold's mounting flange near the top of the pipe forming part that forms the intake pipe. I try to pour hot water from there.

(Function) By locating the chamber forming part that forms the distribution chamber downward, the molten metal poured from near the top of the conduit forming part smoothly flows into the chamber forming part. flowing into
As well as filling the space of the chamber molding part,
It fills the vertical part of the conduit forming part and further flows into the horizontal part of the conduit forming part. Moreover, the molten metal poured from the flange forming part flows into the horizontal part of the pipe forming part and fills the space of the flange forming part.
Therefore, a complete distribution chamber-integrated intake manifold can be obtained by pouring from only two places.

The intake manifold thus cast is then turned upside down and attached to the engine body. Therefore, the sprue marks remaining in the intake pipe section are located on the lower surface of the intake manifold, so that the sprue marks can be used as stay attachment bosses of the intake manifold.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In the drawings, FIG. 1 is a longitudinal cross-sectional view showing one embodiment of a mold used in the method for casting an intake manifold according to the present invention, and FIG. FIG. 3 is a side view showing a state where the device is attached to the main body. 3 and 4 are a plan view and a rear view of the intake manifold, respectively.

First, the intake manifold molded by this casting method will be explained. As shown in FIG.
and the distribution chamber 12 to the engine body 11
The cylinder head 11a has an intake pipe line 13 connected to an intake port 11b formed on the side surface of the cylinder head 11a. The distribution chamber 12 and the intake pipe 13 are integrated. Engine body 11
The engine is an in-line four-cylinder engine, and the distribution chamber 12 has a cylindrical shape that is substantially parallel to the longitudinal direction of the engine body 11. As is clear from FIGS. 3 and 4, the intake pipe 13 has one end open to the distribution chamber 12 and the other end to the cylinder head 1.
Four pipe lines 13 ₁ , 13 ₂ , 13 ₃ , 1 connected to the four intake ports 11b (see Fig. 2) of 1a
3 It consists of ₄ . These pipes 13 ₁ to 13 ₄
The cylinder head 11a side end thereof is integrated with a mounting flange 14, and is fixed to the side surface of the cylinder head 11a by the mounting flange 14.

As is clear from FIG. 2, the intake pipes 13, 1
3 ₁ to 13 ₄ have a vertical portion 13 a extending downward from the distribution chamber 12 and a horizontal portion 13 b extending approximately horizontally from the lower end of the vertical portion 13 a to the mounting flange 14 while being gently curved; The entire intake manifold 10 is approximately L-shaped. An air cleaner 15 is attached to the back of the intake manifold 10, and intake air is introduced into the distribution chamber 12 through a throttle body (not shown) attached to one end surface of the distribution chamber 12. The mounting flange 14 of the intake manifold 10 is provided with a fuel injection nozzle 16 for injecting fuel into each intake port 11b.
is installed.

During operation of the engine, intake air introduced into the distribution chamber 12 through the air cleaner 15 is distributed to each intake line 13 and guided to the corresponding combustion chamber via the intake port 11b of the cylinder head 11a. During this time, fuel is injected from the fuel injection nozzle 16, and its combustion is supplied to the combustion chamber together with intake air.

Next, a method for casting such an intake manifold 10 will be explained.

As shown in FIG. 1, the mold 20 used for the casting is an outer mold 2 divided into an upper mold 21, a lower mold 22, a side mold 23, a shell 24, etc.
5 and a sand core 26. Note that the illustrated dividing line of the outer mold 25 merely indicates that the outer mold 25 is divided, and is actually divided into various shapes in order to facilitate mold cutting. Between these outer mold 25 and core 26,
A space is formed that matches the shape of the intake manifold 10 and corresponds to the wall thickness of each part thereof, and includes a chamber forming part 27 that forms the distribution chamber 12 and a pipe forming part that forms the intake pipe 13. 28,
A flange forming portion 29 for forming the mounting flange 14 is continuously provided.

As shown in the figure, this mold 20 includes a pipe forming part 2 for forming the horizontal part 13b of the intake pipe 13.
The horizontal part 28b of 8 extends substantially horizontally, and the vertical part 28a of the pipe forming part 28 that forms the vertical part 3a of the intake pipe 13 extends downward from the end thereof, and the chamber forming part 27 is located at the lower end thereof. In other words, the intake manifold 10 is held in a state where it is cast upside down from its installed state. In this state, the upper mold 21 has a part that curves upward from the vertical part 28a of the conduit forming part 28 to become the uppermost part.
A sprue 30 is provided for pouring metal from above.
The gates 30 open at three locations corresponding to the adjacent intake pipes 13 ₁ and 13 ₂ , between 13 ₂ and 13 ₃ , and between 13 ₃ and 13 ₄ of the intake manifold 10 .

In this state, the molten metal of the base material of the intake manifold 10 is poured from the sprue 30. Then, the molten metal flows down the vertical part 28a of the pipe forming part 28,
The chamber forming part 27 is filled with the vertical part 2.
8a is also full. It also flows into the horizontal portion 28b of the conduit forming portion 28.

Next, the mold 20 is tilted to form the flange forming part 2.
9 should be positioned above. In the upper mold 21,
A sprue 31 is provided which opens over the entire surface of the flange molded portion 29 and extends in the direction of extension thereof. Therefore, in this state, molten metal is cast from the sprue 31. Thereby, the molten metal comes to fill the horizontal portion 28b of the conduit forming portion 28 and the flange forming portion 29.

The molten metal thus poured into the mold 20 is gradually cooled together with the mold 20. During this time, the inclination of the mold 20 is changed as appropriate to ensure that the molten metal is evenly distributed. At this time, the sprues 30, 31
The molten metal inside functions as a riser.

After solidification, the outer mold 25 is removed and the core 26 is pulled out. Then, the sprue marks are cut and finishing processing is applied.

By gravity casting the intake manifold 10 with it upside down,
Sufficient molten metal is supplied to the chamber molding section 27 located below. Therefore, a distribution chamber 12 formed using a large core and having a thin wall can also be made to have fewer casting defects. Moreover, the intake pipe 1 adjacent to the sprue 30
Between 3 ₁ and 13 ₂ , between 13 ₂ and 13 ₃ , and between 13 ₃ and 13
Since it is placed at a position corresponding to _{the 4} spaces,
The core for molding each of the intake pipes 13 ₁ to 13 ₄ does not become an obstacle, and smooth pouring of the metal becomes possible. Furthermore, by pouring the metal from the flange forming portion 29, the cross-sectional area of the sprue 31 can be increased.

Intake manifold 10 cast in this way
is installed upside down and attached to the engine body 11 as shown in FIG. Therefore, the sprue 3
The sprue mark 35 of No. 0 is on the lower surface side of the intake manifold 10. That is, it is possible to avoid a situation where the sprue marks 35 are visible from above the engine and the appearance is spoiled. And the sprue trace 35,
It can be used as a mounting boss for mounting the support stay 36 of the intake manifold 10 or a mounting seat for mounting a harness stay. The mounting flange 14 side is the cylinder head 1
Since it is finished so that it adheres closely to 1a, there will be no sprue marks left there.

Note that in the above embodiment, the sprue 30 is provided at the top of the pipe forming section 28;
It may be provided at a position slightly closer to the vertical portion 28a than the top. Further, although it is assumed that the metal is poured from the sprue 30 and then from the sprue 31 on the side of the flange forming portion 29, the order may be reversed. As the mold 20, a sand mold can also be used as the outer mold 25.

(Effects of the Invention) As is clear from the above description, according to the present invention, the chamber molding part of the mold for molding the distribution chamber of the intake manifold is positioned downward, and the pipe for molding the intake pipe line Since the molten metal is poured from near the top of the channel forming section, a sufficient amount of molten metal is supplied to the chamber forming section. Therefore, even in the chamber forming part where the flow of molten metal is most problematic, there is no need to separately pour the molten metal, and it is no longer necessary to tilt the mold for pouring the molten metal. That is, the casting operation can be facilitated.

When the intake manifold cast in this way is attached to the engine body, the sprue marks left on the intake pipe are located on the lower surface, so the appearance is affected by the sprue marks. Not only will the sprue marks not be damaged, but the sprue marks can be used as mounting bosses for the support stays of the intake manifold.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a mold used in the method for casting an intake manifold according to the present invention, and FIG. Fig. 3 is a plan view of the intake manifold, Fig. 4 is a rear view of the intake manifold, and Fig. 5 is a partially cutaway side view of the intake manifold. FIG. 2 is a schematic side view showing an example of a manifold. 10... Intake manifold, 11... Engine body, 11a... Cylinder head, 12... Distribution chamber, 13, 13 ₁ , 13 ₂ , 13 ₃ , 13 ₄ ...
Intake pipe line, 13a...Vertical part, 13b...Horizontal part, 14...Mounting flange, 20...Mold, 26
... core, 27 ... chamber forming part, 28 ... pipe forming part, 28a ... vertical part, 28b ... horizontal part, 29 ... flange forming part, 30, 31 ... sprue, 35 ... sprue Trace.

Claims (1)

[Scope of Claims] 1. A distribution chamber 12 disposed on the side of the engine body 11 in the installed state;
A plurality of intake pipes 1 extend substantially horizontally to a mounting flange 14 fixed to the cylinder head 11a of the cylinder head 1.
A method of casting a substantially L-shaped intake manifold 10 in which the intake manifold 10 is integrated with the intake manifold 10; The chamber molding part 27 that molds the chamber 12 is held in a lower position, and in this state, pouring metal from the vicinity of the top of the pipe molding part 28 that molds the intake pipe 13, and the mounting flange. 14. A method for casting an intake manifold integrated with a distribution chamber, characterized by pouring metal from a flange forming part 29 that forms a flange forming part 14. 2. Pouring the molten metal into the conduit forming part 28, the adjacent intake conduit 1 of the intake manifold 10
The method for casting an intake manifold according to claim 1, characterized in that the casting is performed from positions corresponding to positions between 3 ₁ , 13 ₂ ; 13 ₂ , 13 ₃ ; 13 ₃ and 13 ₄ .