JPH06167242A - Finishing work for cylinder bore made of high si aluminium alloy - Google Patents

Abstract

PURPOSE:To permit the projection finishing of primary crystal Si on the bore surface of a cylinder bore made of the high Si aluminum alloy by carrying out the mechanical work without executing the chemical processing, after the finishing horning. CONSTITUTION:In the finishing work for the cylinder bore 2 of a cylinder block 1 made of the high Si aluminium alloy crystallizing primary crystal Si, the cylinder bore surface 2a is subjected to abrasive finishing work by carrying out the finishing horning by using a grinding wheel, and then the brush horning is carried out by using a resin brush planted with the resin hair mixed with abrasive grains.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for finishing a cylinder bore portion in which a piston slides in a cylinder block of an automobile engine, a cylinder of various fluid pressure devices, a cylinder of various pumps, and the like. ,
The present invention relates to a finishing method for a cylinder bore made of high Si aluminum alloy, which is suitable for finishing the cylinder bore portion when the cylinder is made of a high Si aluminum alloy.

[0002]

2. Description of the Related Art Conventionally, for example, in a cylinder block of an automobile engine, cast iron is often used as a material for the cylinder block, and then cast into a cylinder block shape having a number of cylinder bore portions corresponding to four cylinders and six cylinders. Especially, in the cylinder bore part, boring and finishing honing were performed.

In this honing process,
In order to improve the accuracy of the roundness and cylindricity of the cylinder bore, it is divided into roughing and finishing, and a roughing process uses a diamond grindstone, and a finishing process uses a GC grindstone for honing. (For example, “Automotive Technology Handbook” published by the Society of Automotive Engineers of Japan on September 1, 1991 <4th Volume> Production / Quality / Maintenance Edition
Chapter 4 Parts / Units 4.1 Engine No. 197
Pp.-198).

On the other hand, since conventional cast iron has a large specific gravity, it is not preferable for reducing the weight of the engine. Therefore, in order to reduce the weight of the engine, it may be made of aluminum alloy. It has been put to practical use that the cylinder bore portion of which is provided with a cast iron liner, and further, utilization of the primary crystal Si in the high Si aluminum alloy in which primary crystal Si crystallizes has been considered.

In the case of such a high Si aluminum alloy cylinder block, as shown in a model in FIG. 3, the cylinder bore surface 12a of the cylinder bore 12 of the cylinder block 11 is finished with a GC grindstone. After performing honing and polishing finishing of the cylinder bore surface 12a, as shown in FIG.
Cylinder bore surface 12a using sodium hydroxide solution
3 (b), the aluminum portion is removed by about several μm without destroying the primary crystal Si13 on the cylinder bore surface 12a, so that the primary crystal Si13 is relatively removed. Was made to protrude from the cylinder bore surface 12a by about several μm so that the lubricating oil can be retained, so that sufficient lubricity and wear resistance were obtained.

[0006]

However, in such a conventional method for finishing a cylinder bore made of a high Si aluminum alloy, the chemical treatment using the sodium hydroxide solution is performed after the finishing honing is performed. Not only processing equipment but also other nearby processing equipment are susceptible to chemical damage, and it is necessary to manage aqueous solutions used for chemical processing (chemical activity, storage, maintenance of optimum conditions, etc.) It is necessary to dispose of the processed sludge because it causes processing sludge due to chemical treatment, and it is necessary to take environmental conservation measures for the worker and factory environment. There was a point.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the conventional problems caused by the above-mentioned chemical treatment, and it is possible to perform mechanical processing without performing chemical treatment. It is an object of the present invention to make it possible to perform projecting finish processing of primary crystal Si on the bore surface of a cylinder bore made of a high Si aluminum alloy.

[0008]

A method of finishing a cylinder bore made of a high Si aluminum alloy according to the present invention includes: when finishing a bore portion of a cylinder made of a high Si aluminum alloy in which primary crystal Si crystallizes, After finishing honing with a grindstone to polish and finish the surface of the cylinder bore, brush honing with a resin brush with resin bristles mixed with abrasive grains is performed to remove the aluminum part on the surface of the cylinder bore. At the same time, the structure is characterized in that the primary crystal Si is projected and finished on the surface of the cylinder bore relatively.

In the finishing method for a cylinder bore made of a high Si aluminum alloy according to the present invention, as the high Si aluminum alloy, one which crystallizes Si as a primary crystal during casting is used. For example, aluminum defined in JIS H5202 is used. An alloy casting (symbol AC) selected from which primary crystal Si is crystallized at the time of casting is used, and a material containing other appropriate additional elements as needed is used.

Then, after using such a high Si aluminum alloy for casting, it is formed into a cylinder block shape of an automobile engine, for example, in the cylinder bore portion, boring, rough honing, and FIG. 1 (a). The finishing honing as shown in Fig. 1 is performed, and further the brush honing as shown in Fig. 1B is performed.

In this case, rough honing is performed by using, for example, a diamond grindstone, and subsequent finishing honing is performed by using, for example, a GC grindstone. Depending on the characteristic difference between the cylinder bores, the honing conditions are different for each bore. It can also be modified and processed.

Next, when brush honing is performed, as shown in FIG. 2, a resin brush 7 in which resin bristles 6 in which abrasive grains are mixed in resin are planted and aligned is used on the brush base 5.

In this case, hard particles are used as the abrasive grains, and hard particles made of carbides, oxides, nitrides or the like having appropriate hardness and fracture toughness are used. For example, the particle size is # 400. Silicon carbide (SiC) abrasive grains, which are carbide particles of about # 500, are used.

As the resin, a resin having appropriate tensile strength, elongation, bending strength, hardness, etc. is used. For example, polyamide (trade name: 6-nylon, 6,6-nylon, 6 , 12-nylon, aromatic polyamide, etc.) are used.

Then, 20 to 4 hard particles are added to this resin.
0.5 ~ 2.0m diameter of composite resin material mixed with 0% by volume
After obtaining a linear or string-like body of about m, the length is 2
The resin bristles 6 each having a size of about 15 mm are used, and the resin bristles 6 are bundled and planted on the brush base 5, and the resin bristles 7 having the resin bristles 6 aligned are used.

[0016]

In the method of finishing a cylinder bore made of a high Si aluminum alloy according to the present invention, after finishing honing using a grindstone to polish the surface of the cylinder bore, resin bristles containing abrasive grains are aligned. Since brush honing using a resin brush is used to perform projecting finish processing of primary crystal Si on the surface of the cylinder bore, it is not necessary to perform treatment with a chemical such as sodium hydroxide solution as in the conventional case. Since the primary crystal silicon is projected onto the surface of the cylinder bore, for example, in the case of an engine cylinder bore, the presence of the primary crystal Si in the projected state on the surface of the bore improves the retention of the lubricating oil, and An appropriate boundary lubrication surface that can withstand violent reciprocating motion is obtained, and a lightweight aluminum alloy cylinder Becomes the lubricity and wear resistance of the cylinder bore surface in the block is significantly improved.

[0017]

[Examples] When finishing the cylinder bore portion of an engine cylinder block made of a high Si aluminum alloy (A390) having a Si content of 17% by weight, boring of the cylinder bore portion was performed on the cylinder block after casting. After that, rough honing using a diamond grindstone is performed, and then finish honing using a GC grindstone is performed, as shown in FIG.
The cylinder bore surface 2a of the cylinder bore 2 of the cylinder block 1 was polished and finished.

Next, as shown in FIG. 2, a resin brush in which approximately 20% by volume of abrasive particles of # 400 to # 500 made of silicon carbide are mixed and resin bristles 6 having a diameter of 1.5 mm and a length of 10 mm are planted and aligned. 7, and this resin brush 7 is set on the honing head, and brush honing is performed under the conditions of peripheral speed: 60 to 150 m / min, stroke speed: 1 to 8 m / min, expansion pressure: 0.2 to 0.4 Pa. It was

As a result, aluminum is removed on the cylinder bore surface 2a without destroying the primary crystal Si3 on the cylinder bore surface 2a, and as shown in FIG. Si3 is 2-4
It was possible to finish with a protrusion of μm.

And, such a cylinder bore surface 2a
In the cylinder block 1 having the above, since the primary crystal Si3 in a protruding state is present on the cylinder bore surface 2a, the lubricating oil is well retained, so that an appropriate boundary lubrication surface that can withstand the violent reciprocating motion of the piston can be obtained. It was.

[0021]

According to the method of finishing a cylinder bore made of a high Si aluminum alloy according to the present invention, after finishing honing using a grindstone to polish the surface of the bore, the resin bristles mixed with abrasive grains are aligned. Since brush honing using a resin brush was used to perform projecting finish processing of primary crystal Si on the surface of the cylinder bore, aluminum can be removed without destroying primary crystal Si on the surface of the cylinder bore after finishing processing. As a result, the primary crystal Si is, for example, several μm
It can be made to protrude to some extent, and since the protruding state of primary crystal Si can be obtained without chemical treatment as in the past, the problem of using chemicals is solved and only the addition of an inexpensive honing machine is required. Primary Si as an alternative to chemical treatment
That is, it is possible to perform the protruding finish processing, and it is possible to obtain a significantly excellent effect that a cylinder bore surface having good lubricating oil retention and excellent wear resistance can be obtained.

[Brief description of drawings]

1 shows an embodiment of a method for finishing a cylinder bore made of a high Si aluminum alloy according to the present invention, showing the surface of a cylinder bore after finishing honing (shown in (a) of FIG. 1).
FIG. 3 is a model explanatory view of a cylinder bore surface (shown in FIG. 1B) after brush honing.

FIG. 2 is an explanatory diagram showing an outline of a resin brush used in the brush honing of the present invention.

FIG. 3 shows an example of a conventional finishing method for a cylinder bore made of a high Si aluminum alloy, the cylinder bore surface after finishing honing (shown in FIG. 3 (a)) and the cylinder bore surface after chemical treatment ((b) in FIG. 3). It is a model explanatory drawing of ()).

[Explanation of symbols]

 1 Cylinder Block Made of High Si Aluminum Alloy 2 Cylinder Bore 2a Cylinder Bore Surface 3 Primary Crystal Si 5 Brush Base 6 Resin Bristles 7 Resin Brush

Claims (1)

[Claims] 1. When finishing the bore portion of a cylinder made of a high Si aluminum alloy in which primary Si is crystallized, after finishing honing with a grindstone, the cylinder bore surface is polished and finished. A finishing method for a cylinder bore made of a high Si aluminum alloy, characterized by performing brush honing using a resin brush having resin bristles mixed with abrasive grains to perform a projecting finishing process of primary crystal Si on the surface of the cylinder bore.