JPH03113173A - Surface structure of sliding member and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve abrasion resistance and lubricity by forming a holding part for holding the metal particles of a basic material onto the peripheral part of the metal particles. CONSTITUTION:As for the surface of a cylinder inner wall 1, i.e., a sliding surface 1a, a portion of the silicon particles 3 (metal particles), i.e., the sliding surface 3a part of the particles 3 is exposed from the common surface 2a of an Al alloy 2, and an oil reservoir 4 is formed on the stepped part between the sliding surface 3 and the common surface 2a. A holding part 10 is formed on the peripheral surface part of the silicon particle 3. The holding part 10 is formed by grinding-working the surface of the Al alloy 2 by an elastic grindstone 11 until silicon particles 3 are projected, and the part from the common surface 2a of the Al alloy 2 to the sliding surface 3a of the silicon particle 3 is continuously formed into a bank form bulging out to have a corner R, and the silicon particles 3 are fixed firmly by the bank part.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to, for example, a cylinder liner for an engine.

Regarding sliding members used in parts such as pistons that require wear resistance, this method improves the holding power of metal particles, especially when the sliding surface is constructed by exposing metal particles from the surface of the base material. The present invention relates to a surface structure of a sliding member that can prevent metal particles from falling off or caving in, and a method for manufacturing the same.

[Conventional technology]

For example, the inner circumferential wall of an engine cylinder and the outer circumferential wall of a piston slide at high speed and are exposed to high temperature and pressure, so a high silicon aluminum alloy with high wear resistance and a low coefficient of thermal expansion is used. ing. This high-silicon aluminum alloy is composed of a base material made of an aluminum alloy with a small coefficient of thermal expansion mixed with silicon particles that are harder than the base material.

Further, an oil reservoir may be formed on the surface of the high-silicon aluminum alloy, that is, the sliding surface, in order to improve lubricity. This oil pool is constructed by exposing a portion of the silicon particles from the surface of the aluminum alloy to form a step, and interposing oil in the step-down surface portion of the aluminum alloy. Such oil puddles are
Conventionally, it has the shape shown in Figure 5, and this is due to chemical,
It is formed by an electrochemical etching method.

That is, a sliding surface 1a of a high-silicon aluminum alloy l is formed into a flat shape by grinding, and this sliding surface 1a is immersed in an etching solution that corrodes aluminum more than silicon. 1 to 3 only on the surface part of alloy 2
The silicon particles 3 are eroded to a depth t of about .mu.m so that a portion of the silicon particles 3 protrudes from the surface level of the aluminum alloy 2, thereby forming an oil reservoir 4.

[Problem that the invention seeks to solve]

However, as shown in FIG. 6, the surface structure of the conventional sliding member made of a high-silicon aluminum alloy is that the boundary portion 6 of the surface of the aluminum alloy 2 with the silicon particles 3 is hollowed out. The holding force of the silicon particles 3 is that weak, and in some cases, the silicon particles 3 may be held by frictional force.
may fall off.

There is a problem that it is easy to cave in, resulting in a decrease in wear resistance and lubricity. This is because the boundary portion 6 tends to have a high electrolytic density and is also under conditions where it is easily attacked by the etching solution, so it is more easily eroded than other surface portions.

Furthermore, since the silicon particles 3 exposed by etching are in their original shape, the corners 3b of the exposed portions are likely to be destroyed by sliding with the mating member, thereby reducing the wear resistance of the sliding member itself. There is also the problem that the silicon pieces produced by the deterioration or the breakage act as an abrasive, and from this point the wear of each member is likely to progress.

The present invention was made to solve the above-mentioned conventional problems, and it is possible to improve the holding power of silicon particles to avoid falling off, etc., and also to prevent the destruction of silicon particles, which in turn improves wear resistance and lubricity. It is an object of the present invention to provide an improved surface structure of a sliding member and a method for manufacturing the same.

[Means for solving problems]

Therefore, the invention of item 1 of the present application provides a surface structure of a sliding member in which a part of metal particles harder than the base material is exposed from the surface of the base metal. The present invention is characterized in that the base material is arranged along the circumferential surface of the metal particles, and a holding portion for holding the metal particles is formed. In addition, the invention of item 2 of the present application is a method for manufacturing the above-mentioned sliding member, in which the surface of the sliding member is ground to be substantially flat, and then this surface is made of particles having a particle size equal to or smaller than the above-mentioned metal particles. The method is characterized in that the metal particles are ground using an elastic grindstone having abrasive grains until they protrude from the surface of the base material.

Here, the holding portion in the present invention can be specifically realized by processing a continuous portion of the base material with the periphery of the metal particle into a shape having a corner R.

In addition, the elastic grindstone of the invention in Item 2 of the present application refers to a grindstone with a flexible structure in which abrasive grains having a particle size equal to or smaller than metal particles are bonded together with a soft bond, and the elastic grindstone is used for grinding. By performing machining, only the surface portion of the base material can be cut. As such an elastic grindstone, for example, there is a commercially available FRB grindstone (manufactured by Nippon Tokushu Kento Co., Ltd.).

This FBB grindstone has traditionally been used for mirror polishing, and is made of a binder made of polyvinyl alcohol and thermosetting resin, and a large number of pores and abrasive grains, making it extremely flexible. Moreover, it has the feature that the abrasive grains are easily removed.

By employing this FBB grindstone, the surrounding portion of the metal particles of the base material becomes a raised bank-like shape, thereby forming the holding portion of the invention of item 1 of the present application.

Further, for the sliding member of the present invention, it is preferable to use a high-silicon aluminum alloy, which is made of an aluminum alloy as a base material and mixed with silicon particles. However, the scope of application of the present invention is to It is not limited to aluminum alloys, but also SKDll (steel tool dies tli).
It can also be applied to alloys in which CrC is exposed from the surface of 4) or 5KH6, and in short, it can be applied as long as it has a structure in which harder metal particles are exposed on the surface of the metal base material.

[Effect]

According to the surface structure of the sliding member according to the invention of item 1 of the present application,
Since the holding part is formed around the metal particles of the base material, this holding part has a rounded corner shape where the continuous part with the metal particles of the base material is raised, which is different from the structure hollowed out by conventional etching. In comparison, the holding power of metal particles can be improved. As a result, it is possible to avoid the problems of metal particles falling off and sinking, and it is possible to improve wear resistance and lubricity.

In addition, in the invention of item 2, since the surface of the base material is ground with an elastic grindstone, more of the surface portion of the base material is ground, and the metal particles are not ground as much, so a step is created between the two, which causes the oil to become oily. A pool forms. In this case, the surrounding portion of the metal particle of the base material has a continuous rounded corner shape from the surface of the base material to the protruding end of the metal particle, thereby forming the above-mentioned holding portion.

Furthermore, since the corners of the exposed metal particles are rounded off by the above-mentioned elastic grindstone, the corners of the exposed metal particles are not destroyed by friction with the mating member, unlike when conventional metal particles remain in their original shape. This reduces the amount of damage caused by the wear and tear, thereby avoiding aggressiveness and improving wear resistance from this point of view as well.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram for explaining the surface structure of a sliding member according to an embodiment of the invention in Item 1 of the present application, and this embodiment is an example of the case of a high-silicon aluminum alloy used for the inner wall of an engine cylinder. I will explain it to you.

In the figure, 1 is the inner wall of the cylinder made of the high-silicon aluminum alloy of this example, and this is made of silicon particles 3 (particle size 2
0 to 50 μ-). The surface of the cylinder inner wall 1, that is, the sliding surface 1a, is configured by exposing a part of the silicon particles 3, that is, the sliding surface 3a portion of the particles 3 from the general surface 2a of the aluminum alloy 2,
Further, an oil reservoir 4 is formed by a stepped portion between the sliding surface 3a and the general surface 2a.

A holding portion lO is provided on the peripheral surface of the silicon particle 30.
is formed. As described later, this holding part 1O is formed by grinding the aluminum alloy surface with an elastic grindstone 11 until the silicon particles protrude, and is formed by grinding the aluminum alloy surface from the general surface 2a of the aluminum alloy 2 to the sliding surface of the silicon particles 3. It continues up to 3a and has the shape of a bank that swells in the shape of a corner R, whereby the silicon particles 3 are firmly fixed.

Next, a method for manufacturing the above-mentioned surface structure according to an embodiment of the invention of Section 2 of the present application will be explained with reference to FIGS. 1 and 2.

First step: A diamond grindstone (SD12/25 J50MK
6) to form a flat sliding surface 1a (see To in FIG. 2). At this time, the silicon particles 3 are also ground to form particle sliding surfaces 3a.

Second Step Next, the sliding surface 1a is finished by grinding using an elastic grindstone 11 until the sliding surface 3a of the silicon particles 3 protrudes by 1 to 3 μm (FIG. 2(b)).

(See Figure 1).

Here, the elastic grindstone 11 is made by bonding abrasive grains smaller in diameter than the silicon particles 3 with a soft bond, and specifically, an FBB grindstone (porous paycrite bond grindstone) is employed. This FRB grindstone is generally used for super-finishing mirror finishing, and has a size of #600 to 1000. It is constructed by bonding abrasive grains with a particle size of 31 to 45 μm with a soft bond made of polyvinyl alcohol and phenol resin. This FRB grinding wheel is very soft and the abrasive grains easily fall off, making it difficult to cut leather-hard particles, so only the surface of the aluminum alloy 2 is cut, and the corners of the silicon particles 3, which are harder than the alloy 2, are cut. It will be removed. Therefore, by grinding for about 1 minute with the above FRB grindstone,
A step is formed between the surface of the aluminum alloy 2 and the sliding surface 3a of the silicon particles 3, and the general surface 2 of the aluminum alloy 2 is
Part a becomes the oil reservoir 4. In this case, since this FBB grindstone is flexible, the peripheral part of the particles of aluminum alloy 2 is not cut much and remains in the corner R shape described above, thereby creating a bank-like holding structure that supports the silicon particles 3. A section 10 is formed.

As described above, in this example, the holding part 10 was formed around the particles of the aluminum alloy 2 by grinding the silicon particles 3 until the sliding surface 3a of the silicon particles 3 protruded from the level of the aluminum alloy 2 using an elastic FBB grindstone. The holding power of the silicon particles 3 can be improved, and problems of falling off and sinking can be avoided accordingly, and the lubricity and wear resistance of the cylinder inner wall can be improved.

Furthermore, since the end corners of the silicon particles 3 are ground by the FBB grindstone, the exposed corner portions of the silicon particles 3 are rounded accordingly, and breakage due to friction can be avoided, and wear resistance can be improved from this point as well.

Although the above embodiments have been explained using high-silicon aluminum alloy as an example, the present invention is applicable to, for example, 5KDll or 5KH.
It can also be applied to alloys made by mixing 6 and CrC particles, powder metals, alloys made by mixing silicon particles to Cu, etc. In short, it is made by exposing harder metal particles on the surface of the metal base material. It can be applied to any structure.

Further, in the above embodiment, the inner wall of an engine cylinder was used as an example, but the application of the sliding member according to the present invention is not limited to this, and the application is not limited to this, but it may be used in applications such as pistons, clutch housings, etc. that require wear resistance. It will have a great effect if used in parts.

Figures 4 fa+ to 4 (C1 are micrographs showing the surface structure of high-silicon aluminum alloys.

Figure 4 (C1 is a conventional surface structure obtained by etching the surface of a high-silicon aluminum alloy (500x magnification); the white parts in the figure are silicon particles;
The black part around the silicon particle shows a state where it has been hollowed out by etching. From the figure, it can be predicted that the holding power of silicon particles is low when simply etching is performed. On the other hand, Fig. 4+al and Fig. 4(b) show the surface structure of this example obtained by grinding the surface of a high-silicon aluminum alloy with an elastic grindstone (1000 times).
Figure 4 (Al) is the same surface as in Figure 4 (al), with the unevenness made easier to see through image processing, and the white parts are silicon particles.As is clear from this photo,
There is no black part (part gouged out by etching) in the peripheral area of the silicon particle as in the case of Fig. 4 (10), and conversely, there is a rounded corner in the continuous part of the aluminum alloy with the silicon particle. It can be seen that there is a holding portion (see the shaded area 10 in FIG. 3, which schematically depicts the photograph of BL) in FIG. 4 above.

〔Effect of the invention〕

As described above, according to the surface structure of the sliding member according to the invention of item 1 of the present application, since the holding portion is formed around the metal particles of the base material, the holding force of the metal particles can be improved, and the holding force of the metal particles can be improved. According to the manufacturing method according to the invention of item 2, there is an effect of preventing falling off and sinking and improving wear resistance and lubricity.
Since the surface of the base material was ground using an elastic grindstone made of abrasive grains smaller than the grain size of the metal particles, it was possible to realize the above-mentioned holding part, avoid breaking the corners of the metal particles, and further improve wear resistance. There is an effect that can be improved.

[Brief explanation of drawings]

1 and 2 are diagrams for explaining the surface structure of the inner wall of a cylinder and its manufacturing method according to an embodiment of the present invention, and FIG. 1 is a sectional view thereof, and FIGS. Figure (b
) are cross-sectional views showing the manufacturing process, and Figure 3 is a cross-sectional view showing the manufacturing process.
Figure (schematic diagram showing the surface structure of bl, Figure 4(a), Figure 4
Kaiyama) is a micrograph showing the particle structure of the high-silicon aluminum alloy of this example, Fig. 4 tc) is a micrograph showing the conventional particle structure, Fig. 5 tag, (bl and Fig. 6 are respectively the conventional surface It is a sectional view showing the structure and manufacturing method. In the figure, ■ is the inner wall of the cylinder (sliding member), la is the sliding surface (surface), 2 is the aluminum alloy (base material), and 3 is the silicon particle (metal particle). , 10 is a holding part, and 11 is an elastic grindstone.

Claims (1)

[Scope of Claims] (1) A surface structure of a sliding member in which a part of metal particles harder than the base material is exposed from the surface of the base metal, wherein A surface structure of a sliding member, characterized in that a base material is arranged along the circumferential surface of the metal particles, and a holding portion for holding the metal particles is formed. (2) A method for manufacturing a sliding member having a surface structure according to claim 1, which comprises: a first step of grinding the surface of the sliding member into a substantially flat surface; Production of a sliding member characterized by a second step of grinding with an elastic grindstone having abrasive grains having a particle size equal to or smaller than that of the metal particles until some of the metal particles protrude from the surface of the base material. Method. (3) Claim 1, wherein the base material is an aluminum alloy and the metal particles are silicon particles.
Sliding member described in section. (4) Claim 2, characterized in that the base material is an aluminum alloy and the metal particles are silicon particles.
A method for manufacturing a sliding member as described in .