JP3109222B2 - Manufacturing method of cylinder head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head used in an internal combustion engine such as an automobile engine, and more particularly, to a hard overlay layer formed by overlaying a high density energy heat source such as a laser beam in a portion corresponding to a valve seat. And a method of manufacturing a cylinder head having a valve seat finished in a valve seat shape.

[0002]

2. Description of the Related Art FIG. 7 shows a cylinder head having a valve seat which is formed in a valve seat shape by forming a hard overlay layer by overlaying on a portion corresponding to the valve seat.

In the cylinder head 51 shown in FIG.
Port L on the left shows the state after the overlaying, and port R on the right shows the state after the finishing after the overlaying.

As shown in the left port portion L of FIG. 7, in the conventional case, a square concave portion 52 is formed by counterbore processing in a portion corresponding to a valve seat of a cylinder head 51, and the surface of the square concave portion 52 is formed. The hard cladding layer 5 is irradiated with a laser beam 53 as a high-density energy heat source and supplied with a cladding powder 55 from a powder supply nozzle 54.
6, and then finished into a valve seat shape as shown in the right port portion R in FIG.

[0005]

However, a valve seat 57 having a valve seat shape formed by forming a hard overlay layer by overlaying on a portion corresponding to the valve seat as described above.
In the cylinder head 51 provided with the above, the square concave portion 52 is formed by counterbore processing on the surface of the base material for overlaying, and then the overlaying process is performed.
Since the angle change on the wall surface of the angular concave portion 52 is sharp, air bubbles inevitably generated during the overlaying process are caught by these wall surfaces, and thus, a hole is formed between the hard overlay layer 56 and the base material. Defect D such as may often occur, and when the laser beam 53 is used as a processing heat source, the incident angle of the laser beam 53 may suddenly change to cause local unmelting, There was a problem that the adhesion at the portion corresponding to the valve seat was poor and the durability was poor, and further, a high cooling ability could not be obtained.

As shown in FIG. 8, especially in the inter-valve portion 58 having a small heat capacity, even when a high-density energy such as a laser beam 53 is used as a processing heat source, the base material portion has Due to the melting of the build-up alloy, the predetermined hardness and strength may not be obtained from the melting, and furthermore, the square-shaped recess 52 formed by the counterbore processing has a small shelf-shaped area, which is equivalent to a valve seat. Of the build-up alloy on the inner surface of the part F
There are problems such as that may occur.

Therefore, in the prior art, there was a problem to solve the above-mentioned problems.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and does not generate defects such as holes between the hard overlay and the base material. Even when used as a processing heat source, it does not cause local unmelting, has good adhesion at the build-up interface, has excellent cooling ability, and has little dilution at the build-up interface, equivalent to a valve seat equivalent part It is an object of the present invention to provide a method of manufacturing a cylinder head provided with a valve seat having a predetermined hardness and strength free from defects such as chipping.

[0009]

According to a first aspect of the present invention, there is provided a method of manufacturing a cylinder head , comprising: a hard overlay using a high-density energy heat source such as a laser along a portion corresponding to an annular valve seat. After forming a layer, a cylinder head with a valve seat finished in a valve seat shape
When manufacturing, along the part corresponding to the annular valve seat
Said valve seat phase of the cylinder head base material for performing overlaying Te
Meat with a corner R portion in advance by a spot facing on the surface of the department
Smoothly continuous in the cross section perpendicular to the embossing direction
After forming the R shape recess having R shape, characterized in that the configuration is assumed which includes a valve seat and finished after the valve seat shaped to form a hard cladding layer by cladding the R shape recess And

Further, according to a method of manufacturing a cylinder head according to a second aspect of the present invention, a portion corresponding to an annular valve seat is provided.
To manufacture a cylinder head with a valve seat that has been formed into a valve seat shape after forming a hard overlay layer by overlaying using a high-density energy heat source such as a laser
Saishi, a cylinder head base material including the excess thickness portions are provided in advance excess thickness portion on the inner side of the intake / exhaust port end portion of the cylinder head base material for performing overlay along the valve seat portion corresponding to an annular
Of the valve seat equivalent part
To make a cross section in the direction perpendicular to the build-up direction.
R shape having an R shape smoothly continuing from the excess portion
After forming the C-shaped recess, the R-shaped recess is hardened by overlaying.
After forming the buildup layer, the valve
The seat is characterized in that it has a sheet .

FIG. 1 shows an embodiment of the present invention. In the cylinder head 1 shown in FIG. 1, a left port portion L shows a state after the cladding is performed, and a right port portion L shows. R indicates a state after finishing work is performed after overlaying.

A portion 2 corresponding to a valve seat in a port opening of the cylinder head 1 is irradiated with a laser beam 3 as a high-density energy heat source. The light is condensed to an appropriate size by an appropriate light condensing means and is irradiated on the processing surface.

In this process, the valve seat equivalent portion 2 is relatively rotated around the valve axis C in the direction of arrow A, and the surface of the base material portion of the valve seat equivalent portion 2
Make a corner R part by spot facing in advance and orthogonal to the build-up direction
An R-shaped recess 4 having a smoothly continuous R-shape is formed in a cross section in the direction in which the R-shaped portion is formed.

On the R-shaped concave portion 4 having the corner R, a copper-based cladding powder exhibiting good wear resistance (for example, a copper-based powder described in Japanese Patent Application No. 2-295673). An alloy powder 5 is supplied from a powder supply device (not shown) by a powder supply nozzle 6, and a hard overlay 7 is formed on the R-shaped concave portion 4. The hard overlay 7 is multi-layered as required. At this time, the processing portion is protected from an oxidation reaction or the like by flowing the shield gas 8 in the direction of the arrow.

According to the present invention, the cylinder head 1 is provided with a corner R at the valve seat equivalent portion 2 so as to be perpendicular to the build-up direction.
Since the R-shaped recess 4 having a smoothly continuous R-shape is formed in the cross section in the opposite direction, bubbles generated inevitably at the time of overlaying are not trapped on the wall surface, so that the hard overlay 7 and the mother Defects such as voids are unlikely to occur between the material (1).

Further, since the incident angle of the laser beam 3 does not change suddenly, local unmelting hardly occurs, a sound interface is obtained, and the adhesion between the hard overlay 7 and the base material (1) is good. Become.

After the hard overlay layer 7 is formed in this manner, the cylinder head 1 having a predetermined valve seat 9 surface shape is obtained by finishing the valve seat shape.

FIG. 4 shows another embodiment of the present invention. In the cylinder head 1 shown in FIG. 4, the left port portion L shows a state after the cladding is performed, and the right port portion L shows the state. The part R shows a state after finishing is performed after overlaying.

A portion corresponding to a valve seat 2 at a port opening of the cylinder head 1 is irradiated with a laser beam 3 as a high-density energy heat source. The light is condensed to an appropriate size by an appropriate light condensing means and is irradiated on the processing surface.

In this process, the valve seat equivalent portion 2 is relatively rotated around the valve axis C in the direction of arrow A, and is preliminarily provided inside the suction / exhaust port end of the cylinder head base material for building up. A surplus portion 10 is provided.

A corner R portion is previously formed on the surface of the cylinder head base material provided with the surplus portion 10 by spot facing.
An R-shaped recess 4 having an R- shape that is smoothly continuous from the surplus portion 10 in a cross section in a direction orthogonal to the build-up direction.
There you like are formed.

On the R-shaped concave portion 4 smoothly continuing from the surplus portion 10, a copper-based overlaying powder exhibiting good wear resistance (for example, as described above, Japanese Patent Application No. 2-29567).
No. 3 is supplied by a powder supply nozzle 6 from a powder supply device (not shown).
The hard overlay layer 7 is formed on the shape recess 4. The hard overlay 7 is multi-layered as required. At this time,
By flowing the shield gas 8 in the direction of the arrow, the processing portion is protected from an oxidation reaction or the like.

In the present invention, since the excess thickness portion 10 is provided in advance inside the suction / exhaust port end of the cylinder head base material, the heat capacity of the base material side even if the build-up portion is the inter-valve portion 12. Since there is no shortage, the build-up processing with less dilution is performed.

In addition, the surplus portion 10 is provided with an R-shaped concave portion 4 having a smoothly continuous R portion from the base material portion, so that air bubbles inevitably generated during overlaying are formed. Is no longer caught on the wall surface, so that defects such as voids are unlikely to occur between the hard overlay 7 and the base material (1).

Further, since the incident angle of the laser beam 3 does not change suddenly, local unmelting hardly occurs, a sound interface is obtained, and the adhesion between the hard overlay 7 and the base material (1) is good. Become.

After the hard overlay layer 7 is formed in this way, the cylinder head 1 having a predetermined surface shape of the valve seat 9 is obtained by finishing the valve seat shape.

[0027]

The method of manufacturing the cylinder head according to the present invention.
According to the method , a corner R is previously formed by spot facing on the surface of a cylinder head base material for overlaying using a high-density energy heat source, so that a smooth cross section in a direction perpendicular to the overlay direction is formed.
Because has a structure that is as provided with a valve seat and finished after the valve seat shaped to form a hard cladding layer by cladding the R-shaped recess to form a R-shaped recess having a connection to R shape, meat Since bubbles inevitably generated during embossing are not caught on the wall, defects such as voids are unlikely to occur between the hard overlay and the base material, and laser light is used as a high-density energy heat source. In this case, since the incident angle does not change suddenly, local unmelting hardly occurs, a sound interface is obtained, and the adhesion between the hard overlay and the base material is improved.

A valve is formed by providing a spare portion in advance inside the suction / exhaust port end of the cylinder head base material for performing the overlay, and forming a hard overlay layer by overlaying on a portion including the excess portion. By adopting a configuration with a valve seat finished in a sheet shape, since the build-up portion is not an inter-valve portion, there is no shortage of heat capacity on the base material side, a build-up process with little dilution is performed, A hardfacing layer is formed on the surface of the cylinder head base material provided with the surplus portion by forming a R-shaped recess having an R portion smoothly continuous from the surplus portion by counterbore machining in advance. By forming a valve seat that is formed into a valve seat shape, air bubbles that are inevitably generated at the time of overlaying will not be caught on the wall surface, so that the hard overlay layer and the base material Lack of voids, etc. Is hard to occur, and when laser light is used, the angle of incidence does not change suddenly, so that local unmelting hardly occurs, a sound interface is obtained, and the adhesion between the hard overlay and the base material is improved. The cylinder head is provided with a valve seat having improved hardness and strength.

[0029]

【Example】

(Embodiment 1) In Embodiment 1, the results of the embodiment of the present invention described with reference to FIG. 1 will be described with reference to FIGS.

In the first embodiment, a corner R is formed in a valve seat equivalent portion 2 on which a hard overlay layer 7 of a cylinder head 1 made of an aluminum alloy (JIS AC4B) is to be formed.
After forming the R-shaped concave portion 4 inclined by 30 degrees with 10R as a counterbore, a copper cladding material having an average particle size of 100 μm, weight%, Al: 8%, Ni: 5%,
A cladding powder 5 containing 3% of Fe and the balance consisting of Cu and unavoidable impurities is used. As laser light 3, power density: 2000 W / mm ² , output mode: multi mode, relative moving speed: 0. 2m / min, shielding gas:
Ar, a shielding gas flow rate: 10 l / min, a supply amount of the copper-based overlaying alloy powder: 25 g / min, and a hard overlay layer 7 having a thickness of 3 mm is formed, and further finishing is performed. Thereby, the surface shape of the valve seat 9 was processed.

FIG. 2 shows a main part of the cylinder head 1 manufactured in the first embodiment, wherein 11 is a cylinder head main body, 12 is an intake / exhaust port, 13 is a part of a combustion chamber, 14 Denotes an engine valve, and 9 denotes a valve seat.

The base material side surface on which the valve seat 9 is formed is formed with an R-shaped concave portion 4 having a corner R having a corner R of 10R and a corner R inclined at 30 degrees. In FIG. 3, as shown in an enlarged manner in FIG. 3, there is no defect such as a void between the hard overlay layer 7 and the base material (11), and the adhesion between the hard overlay layer 7 and the base material (11). The properties were remarkably good and the thermal conductivity was excellent.

(Embodiment 2) In this embodiment 2, the results of another embodiment of the present invention described with reference to FIG. 4 will be described with reference to FIGS.

In the second embodiment, a 6 mm thick excess portion 10 is provided in advance at the end of the intake / exhaust port of the cylinder head 1 made of an aluminum alloy (JIS AC4B), and a valve seat including the excess thickness 10 is provided. After forming an R-shaped concave portion 4 having a corner R of 10R and a slope of 30 degrees in the portion 2 by spot facing, as a copper-based overlay material, an average particle diameter of 100 μm, weight%, Al: 8%, Ni: 5
%, Fe: 3%, and the balance is made of powder for overlay 5 composed of Cu and unavoidable impurities.
Power density: 2000 W / mm ² , output mode: multi-mode, relative moving speed: 0.2 m / min, shielding gas: Ar, shielding gas flow rate: 10 l / min, supply amount of copper-based cladding alloy powder: 25 g The hard overlay layer 7 having a thickness of 3 mm was formed under the overlay condition of / min, and the surface of the valve seat 9 was processed by a finishing process.

FIG. 5 shows a main part of the cylinder head 1 manufactured in the second embodiment, in which 11 is a cylinder head main body, 12 is an intake / exhaust port, 13 is a part of a combustion chamber, 14 Denotes an engine valve, and 9 denotes a valve seat.

The base material side surface on which the valve seat 9 is formed is formed with an R-shaped concave portion 4 having a corner R having a corner R of 10R and a corner R inclined at 30 degrees. In FIG. 6, there is no defect such as a void between the hard overlay 7 and the base material (11) as shown in an enlarged view in FIG. The properties were remarkably good and the thermal conductivity was excellent. Also, no dilution was observed at the cladding interface even in the inter-valve portion where the heat capacity was small, and it was possible to obtain the required hardness and strength, and it was recognized that there was no defect such as missing in the valve seat equivalent portion. Was done.

[0037]

The manufacturing method of the cylinder head according to the present invention.
According to the method , a corner R is previously formed by spot facing on the surface of a cylinder head base material for overlaying using a high-density energy heat source, so that a smooth cross section in a direction perpendicular to the overlay direction is formed.
Because it was configured to that provided with a valve seat and finished after the valve seat shaped to form a hard cladding layer by cladding the R-shaped recess to form a R-shaped recess having a R shape continues, meat Since bubbles inevitably generated during embossing are not caught on the wall, defects such as voids are unlikely to occur between the hard overlay and the base material, and laser light is used as a high-density energy heat source. In this case, the incident angle does not change suddenly, so that local unmelting hardly occurs, a sound interface is obtained, and a remarkably excellent effect of improving the adhesion between the hard overlay and the base material is brought about. .

Further , after forming a surplus portion inside the end of the suction / exhaust port of the cylinder head base material for performing the cladding and forming a hard cladding layer by cladding on a portion including the surplus portion. that includes a valve seat and finished bar <br/> Rubushito shape
By forming a configuration in which a, since the buildup part eliminates the heat capacity shortage of the base material side a valve space portion, is made less buildup processing of diluted further, a cylinder head provided with a excess thickness portion Corner R part by spot facing in advance on the base metal surface
An R-shaped recess having an R- shape smoothly continuing from the excess portion was formed in a cross section in a direction perpendicular to the overlay direction, and a hard overlay layer was formed by overlaying in the R-shaped recess .
By forming a configuration is assumed which includes a valve seat and finished after the valve seat shape, bubbles inevitably occur during the cladding process because no longer be captured by the wall surface, the hard cladding layer and the base material It is difficult for defects such as voids to occur between them, and when laser light is used, the incident angle does not change abruptly, so that local unmelting hardly occurs, a sound interface is obtained, and the hard overlay layer can be obtained. A remarkably excellent effect is obtained in that the adhesion to the base material is improved, and a cylinder head having a valve seat having excellent hardness and strength can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a state after a cladding is performed on a portion corresponding to a valve seat of a cylinder head and a state after finishing is performed after the cladding is performed in an embodiment of the present invention. .

FIG. 2 is an explanatory sectional view of a cylinder head according to a first embodiment of the present invention;

FIG. 3 is an explanatory sectional view showing, on an enlarged scale, a valve seat portion of the cylinder head shown in FIG. 2;

FIG. 4 is a cross-sectional explanatory view showing a state in which a portion corresponding to a valve seat of a cylinder head has been overlaid and a state in which finishing has been performed after overlaying in another embodiment of the present invention. is there.

FIG. 5 is an explanatory cross-sectional view of a cylinder head according to a second embodiment based on another embodiment of the present invention.

FIG. 6 is an enlarged sectional view showing a valve seat portion of the cylinder head shown in FIG. 5;

FIG. 7 is an explanatory cross-sectional view showing a state after a cladding is formed on a portion corresponding to a valve seat of a conventional cylinder head and a state after finishing is performed after the cladding is performed.

FIG. 8 is an explanatory cross-sectional view showing a state in which a portion corresponding to a valve seat of a conventional cylinder head is overlaid and a state after finishing is performed after the overlay is performed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Valve seat equivalent part 3 Laser light (high-density energy heat source) 4 R-shaped concave part 5 Overlay powder 6 Powder supply nozzle 7 Hard overlay layer 9 Valve seat 10 Extra part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02F 1/42 F02F 1/24

Claims (3)

(57) [Claims] 1. A cylinder head having a valve seat formed in a valve seat shape after forming a hard overlay layer by overlaying using a high density energy heat source such as a laser along a portion corresponding to an annular valve seat. In manufacturing,
The surface of the valve seat equivalent portion of the cylinder head base material for overlaying along the annular valve seat equivalent portion is provided with a corner R portion by spot facing in advance, so that the cross section in the direction orthogonal to the cladding direction is smooth. A cylinder having a R-shaped recess having a continuous R-shape, a valve seat formed in a hard-facing layer by overlaying in the R-shaped recess, and a valve seat finished in a valve seat shape. Head manufacturing method. 2. A cylinder head having a valve seat finished in a valve seat shape after forming a hard overlay layer by overlaying using a high-density energy heat source such as a laser along a portion corresponding to an annular valve seat. In manufacturing,
A spare portion is provided in advance inside the suction / exhaust port end of the cylinder head base material which builds up along the annular valve seat equivalent portion, and the cylinder head base material including the surplus portion corresponds to the valve seat. After forming an R-shaped recess in the section perpendicular to the build-up direction by forming a corner R portion in advance in the surface of the portion by spot facing, forming an R-shaped recess having an R shape that is smoothly continuous from the excess portion. A method of manufacturing a cylinder head, comprising: forming a hard overlay layer by overlaying on a valve seat and then finishing the valve seat in a valve seat shape. 3. An R-shaped concave portion having a corner R portion inclined at 30 degrees with a corner R of 10R is formed in the surface of a portion corresponding to a valve seat by a counterbore processing in advance.
3. The method for manufacturing a cylinder head according to item 1.