JP2014141928A - Aluminum casting product with pipe member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum casting product with a pipe member effective in reducing its weight, the number of parts, and man-hour for processing/assembling, and capable of being inexpensively produced.SOLUTION: An aluminum casting product having a pipe member attached thereto is produced by insert casting such that one opening of the pipe member is closed and the other opening is protruded outside, and a draft hole with a predetermined diameter is bored on a closing part which is formed by closing the one opening of the pipe member with the insert casting.

Description

  The present invention relates to a structure for attaching a pipe member to an aluminum casting product such as a cylinder head cover of an engine.

For example, the cylinder head cover 10 as shown in FIG. 4 has a function of separating the unburned mixed gas (blow-by gas) and oil mist in addition to the function as a lid member for closing the upper part of the engine, and this blow-by gas is passed through the PCV valve. There is a PCV function for returning to the combustion system again.
Here, PCV is an abbreviation of Positive Crankcase Ventilation, and contributes to the improvement of the life of the engine oil by keeping the inside of the engine in a clean state.
Therefore, an intake pipe member for sending air from the air cleaner to the PCV system is attached to the cylinder head cover.
A conventional method of attaching a pipe member such as an intake pipe is shown in FIG.
FIG. 5A shows only the portion of the rough hole 113, but a cylinder head cover having such a rough hole 113 is cast by aluminum die casting or the like.
Then cutting the diameter _{D 0} of the crude form holes 113 in the state of the casting surface in the radial _{D 1} of the fitting hole 113a.
Diameter D ₁ of the press-in hole 113a, as well as having a high dimensional accuracy in order to ensure the press-fit strength, there needs to be thicker than the thickness of the general portion in the strength of the aluminum casting boss 111a is needed .
Next, as shown in FIG. 5C, a metal pipe member 112 was press-fitted.
Moreover, the process of apply | coating an adhesive agent to a press-fit surface was also required.
Here, in order to hole diameter d ₁ of the vent 113a for intake in the form and size of the engine is different, different pipe member hole diameter d ₁ there is a problem that required.
Further, when a plurality of types of pipe member hole diameter d ₁ is different there was also a risk of erroneous assembly.
Patent Document 1 discloses a technique for integrally forming a pipe-shaped gas outlet into an aluminum casting instead of the conventional press fitting of a pipe member as a blow-by gas extraction structure of a rocker cover, but ensures the dimensional accuracy of the hole diameter only by casting. It is not possible to secure the connection sealing performance of a hose or the like.

Japanese Utility Model Publication No. 56-143544

  An object is to provide an aluminum casting product with a pipe member that is effective in reducing the weight, reducing the number of parts, reducing the number of processing and assembling steps, and can be manufactured at low cost.

The present invention is characterized in that the pipe member is not attached after the aluminum casting is cast, but the pipe member is insert-cast, and then the vent hole is drilled, and can be widely applied to such aluminum casting products.
Specifically, it is an aluminum casting product to which a pipe member is attached, which is insert-cast so that one opening of the pipe member is closed and the other opening protrudes outward. A vent hole having a predetermined diameter is perforated in a closed portion where one opening portion of the member is closed.

  The present invention is particularly effective when the cast aluminum product is an engine cylinder head cover and the pipe member is a PCV intake pipe.

In the present invention, when an aluminum casting product is cast by a die casting method or the like, the pipe member is attached to the aluminum casting product by insert casting in which a pipe member is arranged in advance in a mold, so that a conventional adhesive is applied. The process and press-fitting process are eliminated, and the number of assembly steps is reduced accordingly, and these facilities become unnecessary.
Further, conventionally, in order to secure the press-fitting strength of the pipe member and the like, high dimensional accuracy is required for the drilling of the pilot hole, and it is necessary to increase the thickness of the mounting boss portion. The processing accuracy of the vent hole by post-processing is less demanding than the accuracy of the press-fitting pilot hole processing, so that the processing man-hours can be reduced, and the wall thickness of the mounting boss part can be about the same as the general wall thickness. It is possible to reduce the weight.
Furthermore, the pipe member can be shared, and there is no risk of erroneous assembly.

The cross section of a cylinder head cover is shown typically. (A) shows the state which cast the pipe member by insert casting, and (b) shows the state which vent hole 13 was drilled. (A), (b) shows the example from which the diameter of a vent hole differs, (c) shows the example which formed the convex part in the outer peripheral part of a pipe member. An example of a cylinder head cover is shown. A conventional pipe member mounting process is shown in FIGS.

As an example of an aluminum casting product with a pipe member according to the present invention, a cylinder head cover by die casting is taken up and described below, but the present invention is not limited to this embodiment.
FIG. 1 schematically shows a cross section of a cylinder head cover 10 to which a pipe member 12 is attached.
Although FIG. 1 shows an example in which the pipe member 12 is attached in a substantially vertical direction, the pipe member 12 may be attached to a side portion of the cylinder head cover 10 in a substantially horizontal direction.
Valves 20 such as tappets for intake and exhaust into the cylinder are provided in the upper part of the engine, and a pipe member is connected to the cylinder head cover 10 for discharging the generated blow-by gas through a PCV valve (not shown). 12 is attached.
The pipe member 12 is partly cast by the cast member 11, and a vent hole (intake hole) 13 is formed in the cast part by post-processing.
A hose or the like is attached to the projecting portion on the outside of the pipe member 12, and air from the air cleaner is sent in.

Next, a manufacturing method is demonstrated based on FIG.
FIG. 2A shows only the vicinity of the pipe member attachment portion of the cylinder head cover 10.
Although not shown, the pipe member 12 is disposed in the die casting mold.
A pin portion or the like is provided in the mold, and the pipe member 12 is inserted into the pin portion or the like so that the molten aluminum does not enter from one opening 12b of the pipe member 12.
The other opening 12a of the pipe member is disposed so as to protrude to the outside of the cylinder head cover 10, and a tube member such as a hose is connected to this portion.
When the pipe member 12 is insert-cast in this manner, as shown in FIG. 2A, a casting portion 11 of the pipe member 12, which is a closing portion 11 a that closes one opening 12 b of the pipe member 12, is formed.
Further, the thickness of the boss-like cast portion 11 may be equal to the thickness of other general portions.
Next, as shown in FIG. 2B, a hole 13 is formed in the closing portion 11a using a drill or the like.
The processing accuracy of the vent hole 13 may be about ± 0.5 mm, and the standard may be looser than the accuracy of conventional press-fit pilot hole processing +0.10 to −0.15 mm.
Since the vent hole 13 is post-processed after casting as described above, the post-process may be performed corresponding to the required hole diameters d ₁ and d ₂ as shown in FIGS. Can be shared.
Further, the pipe member 12 does not need to be limited to a straight shape, and if the projections 12c and 12d are provided on the casting side or the protruding side of the pipe member 12 as shown in FIG. Arise.
Moreover, there is no restriction | limiting in the shape of a convex part, A ring shape or several protrusion shape may be sufficient.

10 Cast aluminum products (cylinder head cover)
11 Casting part 11a Blocking part 12 Pipe member 13 Ventilation hole

Claims (2)

It is an aluminum casting product with pipe members attached,
One of the opening portions of the pipe member is closed, and the other opening portion is insert-casted so as to protrude outward, and the opening portion of the pipe member closed by the insert casting has a predetermined diameter. An aluminum casting product characterized by being perforated.   2. The cast aluminum product according to claim 1, wherein the cast aluminum product is an engine cylinder head cover, and the pipe member is a PCV intake pipe.

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