JPS60177103A - Formation of wear resistant sliding surface - Google Patents

Abstract

PURPOSE:To form easily a wear resistant sliding surface formed with a recess for lubricating oil by forming the recess on the surface of a metallic base body, adhering a sheet of a wear resistant powder alloy to the surface of the base body and heating the same to sink the powder alloy into the recess. CONSTITUTION:A recess 7 for sinking is formed on the surface of a chip 3 as a metallic base body. A powder alloy sheet 8 manufactured by kneading wear resistant alloy powder and resin binder is adhered to the surface of the chip 3. The chip is put into a heating furnace and is heated to the semi-liquid phase sintering temp. of the powder alloy to make the alloy powder slightly fluid so as to sink into the recess 7. A sintered alloy layer 5 is thus formed on the surface of the chip 3 and a recess 6 for lubricating oil is automatically formed on the surface thereof, by which the wear resistant sliding surface is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention comprises a sintered metal layer on the surface of a metal substrate that requires wear resistance, and also prevents oil pools and oil from forming on the surface of the sintered metal layer. The present invention relates to a method for forming a wear-resistant sliding surface in which four lubricating oil portions are formed as grooves.

(Prior art) For example, in the rocker arm of an internal combustion engine, the main body is made of aluminum alloy to reduce weight, while the part that comes into contact with the cam is made of steel to ensure wear resistance. A sintered metal layer is formed as a wear-resistant layer on the side of the chip that comes in contact with the cam. Such a sintered metal layer is
For example, as shown in Japanese Unexamined Patent Publication No. 52-65111, a powder alloy sheet made of a kneaded material of wear-resistant alloy powder and a resin binder is adhered to the surface of the chip piece, and then heated and sintered. can be formed. Conventionally, recesses for lubricating oil as oil reservoirs and oil grooves for improving lubricity were formed at predetermined locations on the surface of the sintered metal layer by cutting.

However, cutting an extremely hard sintered metal layer places a heavy burden on the cutting tool, and there is a risk of cracking or chipping the sintered metal layer if an impact is applied inadvertently during cutting. For.

This is unfavorable for processing. In particular, depending on the shape of the lubricating oil recess, the cutting process may have to be a so-called undercut, and in this case, the cutting process becomes more difficult.

(Object of the invention) The present invention has been made in consideration of the above-mentioned circumstances.
A wear-resistant slide that allows recesses for lubricating oil to be formed as oil reservoirs and oil grooves on the surface of a sintered metal layer as a wear-resistant layer without performing any post-processing on the sintered metal layer. The purpose of the present invention is to provide a method for forming a moving surface.

(Structure of the Invention) The present invention was made based on the fact that when a powder alloy sheet is heated to a semi-liquid phase sintering temperature, fluidity occurs in the alloy powder (semi-liquid phase alloy powder). It is something.

Specifically, on the surface of a metal base such as a chip that requires wear resistance, four sinking parts are formed at locations corresponding to the areas where four parts for lubricating oil are desired to be formed as oil reservoirs and oil grooves. Then, a powder alloy sheet made of a mixture of wear-resistant alloy powder and resin binder is adhered to the surface of the metal base having the four sinking parts, and heated at this latter half liquid phase sintering temperature. A wear-resistant alloy is sunk into the sinking recess to obtain a sintered metal layer as a wear-resistant layer in which lubricating oil recesses as oil reservoirs and oil grooves are exposed in areas corresponding to the sinking recesses. This is how it was done.

(Example) In this example, a case will be described in which a sintered metal layer as a wear-resistant layer is formed on the surface of a chip piece of a rocker arm.

In FIG. 1, A is a rocker arm which is swingable about a support shaft 1. The main body 2 of the rocker arm A is made of a light metal such as an aluminum alloy, and a tip piece 3 made of, for example, steel is cast into the negative swinging end.

This chip piece 3 has a spherical surface on its surface, that is, the side that contacts the cam 4, and such a surface has a spherical surface.
A sintered metal layer 5 is formed as a wear-resistant layer. A lubricating oil recess 6 is formed on the surface of this sintered metal layer 5.

Next, the method of the present invention for obtaining the sintered metal layer 5 having the above-mentioned lubricating oil recesses 6 will be explained with reference to FIGS. 2 to 4. On the surface of the chip piece 3 as a metal base, a second
As shown in the figure, a sinking recess 7 is formed in advance at a location corresponding to the region where the lubricating oil recess 6 is desired to be formed (in the embodiment, the central portion). A powder alloy sheet 8 made of a mixture of wear-resistant alloy powder and a resin binder is adhered to the surface of the chip piece 3 having such a sinking recess 7 . After this, such a chip piece 3 and a powder alloy sheet 8
Put the glued body into the heating furnace.

Heat to the semi-liquid phase sintering temperature of the powder alloy. Through this heating, a sintered metal layer 5 is formed on the surface of the chip piece 3, as shown in FIGS. 3 and 4. By heating at a semi-liquid phase sintering temperature, the alloy powder Since it has some fluidity, it sinks into the subsidence river recess 7, and as a result, a lubricating oil recess 6 is formed on the surface of the obtained sintered metal layer 5 in response to the above-mentioned subsidence. It will be automatically formed. Note that, as in the conventional case, the surface (sliding surface) of the sintered metal layer 5 may be finished by grinding or the like.

Here, the four sinking parts 7 may be formed, for example, by cutting the surface of the chip piece 3, but since the material of the chip piece 3 is sufficiently soft compared to the sintered metal layer as the wear-resistant layer, No special problems arise during processing.
Further, when the chip piece 3 is formed by plastic working such as forging, it can be formed at the same time as this forming. Of course, this sinking recess 7 is set to a predetermined shape and size in accordance with the desired shape of the lubricating oil recess 5 and the sinking of the alloy powder. In addition, since the powder alloy sheet 8 shrinks slightly before being sintered, the size of the powder alloy sheet 8 is made slightly larger than this in accordance with the shape of the surface of the chip piece 3 (see Fig. 2). In order to adhere the alloy sheet 8 to the surface of the chip piece 3, the self-adhesive property (adhesiveness due to the resin binder) of the powder alloy sheet 8 itself may be used, but if this self-adhesive force is insufficient Alternatively, a separate adhesive (including one processed into double-sided adhesive tape) may be used. Of course, the lubricating oil recess 6 may be in the shape of a groove (in this case, the sinking recess 7 is also groove-shaped), and it may also be used in other parts than the tip piece 3 of the rocker arm A, such as the pressing end surface of a tappet in an internal combustion engine. The present invention can be applied to any appropriate member, such as applying the present invention to a part (in this case, the tappet becomes a metal base).

Next, although it is possible to use a known powder alloy sheet 8' as is, it is preferable to use one as described below.

First, as the resin binder, it is best to use an acrylic resin made of an acrylic polymer or copolymer that has pressure-sensitive adhesive properties at room temperature.This acrylic resin has sufficient adhesiveness (tackiness) at room temperature. Even when used as a resin binder, this adhesive property is maintained without burning out even at extremely high temperatures. Furthermore, gas is not generated rapidly and its diffusion is smooth, making it easy to use as a powder. This makes it difficult for so-called bulges to occur in the alloy sheet 8.

The acrylic resin used as the resin binder begins to turn into tar and pitch at around 300°C, and the bonding force to the metal substrate (chip piece 3 in the example) is gradually transferred from the resin to tar and pitch-like substances. As a result, an alloy having adhesion or bondability to the metal substrate up to a temperature at which sintering of the powder alloy starts can be obtained. That is, even if the bonded body of the metal base and the powder alloy sheet 8 having an acrylic resin as a binder is subjected to some vibration while being conveyed and heated, the powder alloy sheet 8 will not touch the metal base. Even when the powder alloy sheet 8 is adhered to an inclined surface (including a vertical surface) of a metal base without causing any displacement, this powder alloy sheet 8
will not fall off from the metal base midway.

Acrylic resin as such a binder is 3% by volume
It is preferable that the acrylic resin is in the range of ~15% by volume (alloy powder is 85% to 97% by volume), that is, the acrylic resin is 3% by volume.
If it is less than 15% by volume, it will be difficult to ensure the adhesiveness and flexibility of the powder alloy sheet, and if it exceeds 15% by volume, it will tend to have a negative effect on the porosity of the obtained sintered metal layer 5, and the bond with the metal substrate will deteriorate. It becomes difficult to obtain sufficient bonding properties. As well known, the acrylic resin may be a polymer or copolymer of acrylic esters or methacrylic esters, and has pressure-sensitive adhesive properties at room temperature.

Next, as the wear-resistant alloy powder, resin (resin) (lower sintering temperature is preferable because there is a limit to the adhesion by the inder, therefore, eutectic alloy, especially Fe-
It is preferable to use a ternary eutectic alloy of the M-C system.
M in the e-M-C system is preferably one of P, Mo, and B, or a composite thereof.

When P is used as this M, it is preferable because it has strong diffusibility into the metal substrate like C, and it also combines with Fe and C to form a phosphorus eutectic, which improves wear resistance and improves the melting point. It plays the role of lowering the This P is preferably 0.5% by weight or more in order to ensure a certain amount of liquid phase or more, and preferably 2.5% by weight or less in consideration of ensuring toughness.

C in the Fe-M-C system works together with P to strengthen the base and form a hard phase, and also forms a phosphorus eutectic, which is useful for increasing density and bonding with the metal substrate. . The proportion of C should be 1.5% by weight or more in consideration of the increase in density and bondability with the metal substrate, and 4.5% by weight or more in consideration of the excessive appearance of the liquid phase and the effect on toughness. 0
It is preferable that the amount is less than % by weight.

When M in the Fe-M-C system is Mo, it contributes to strengthening the base and forming a hard phase, and also combines with Fe and C to lower the melting point, preventing the hard phase from becoming too small. It is preferable to set the content to 2.5% by weight or more in consideration of ensuring density, and to set the content to 1000% by weight or less in consideration of toughness.

When M in the Fe-M-C system is B, Fe,
It combines with C to form a hard phase and plays the role of lowering the melting point. Considering wear resistance, the content should be 0.5% by weight or more, and considering brittleness, the content should be 3.0% by weight or less. good.

Furthermore, as subsidiary elements, Cr, V, W, Nb, T
a, Ti is valid. In other words, these elements are useful for strengthening the matrix, particularly improving toughness, and are preferable because they combine with C to form a hard phase, but if it exceeds 10.0% by weight, the above effects are saturated, so it is not economically viable. Not necessary. In addition, Si is preferably used to improve the fluidity of the molten metal during alloy powder production and to improve the wettability with metal substrates during bonding, but in consideration of wear resistance, Si should be used at 5.0% by weight or less. It is better to do so. Further, Ni and Mn are useful for strengthening the base, but in consideration of wear resistance, it is preferable to limit the content to 5.0% by weight or less.

The particle size of the alloy powder is a factor that greatly affects the porosity of the sintered layer, and is preferably set to 150 mesh or less in consideration of wear resistance.

Here, if the bonded body of the metal base and the powder alloy sheet 8 is likely to be accompanied by particularly large vibrations, for example, if a mesh belt type, pusher set continuous sintering furnace, vacuum sintering furnace, etc. are used, the powder alloy sheet 8 In order to further strengthen adhesion or bonding to the metal substrate, a separate adhesive may be used as described above. After bonding the powder alloy sheet 8 to the metal substrate with a resin binder made of acrylic resin or an adhesive, the powder alloy sheet 8 is heated to a temperature of 150°C to 380°C (preferably 200°C).
It is preferable to maintain this temperature for 5 minutes or more at a temperature of 00° C. to 350° C., and then raise the temperature to a predetermined sintering temperature.

In this way, the adhesive starts to volatilize around 120°C, and from around 200°C, a thermal decomposition polycondensation reaction occurs to generate a tar pitch-like substance, and the adhesiveness of this tar pitch-like substance increases the sintering temperature. Until then, the adhesion or bondability between the powder alloy sheet 8 and the metal substrate is ensured.

If the temperature for obtaining the tar pitch-like substance is less than 150°C, the amount of undecomposed material will increase, which is undesirable.
Conversely, when heated above 0°C, the undecomposed amount rapidly decomposes and gasifies, resulting in less tar pitch-like substances being produced.
This is not preferred in terms of obtaining sufficient adhesiveness or bonding properties. Further, the optimal holding time varies depending on the heat treatment temperature, but if it is less than 5 minutes, the amount of tar pitch-like substances produced is small and sufficient adhesiveness cannot be obtained, and if the holding time is 120 minutes or more, This is unnecessary in order to ensure sufficient production of tar pitch-like substances.

Furthermore, the temperature increase rate to the sintering temperature is preferably 10°C/min to 40°C/min, and particularly preferably 40°C/min or less until the temperature near the end of thermal decomposition of the resin binder. . In other words, if the temperature exceeds 40°C/min, the low boiling point seafood in the resin binder will rapidly volatilize, which may damage the powder alloy sheet 8 or create bubbles on the adhesive surface, which is undesirable. If the speed is high, the liquid phase (metallic liquid phase) is less likely to appear. The appearance ratio of this liquid phase is preferably 10% or more in consideration of bondability with the metal substrate, and is preferably 50% or less in order to maintain the shape of the powder alloy sheet 8. The appearance ratio of the liquid phase may be adjusted as appropriate by taking these points into account and also taking into account the fluidity of the powder alloy sheet 8.

(Effects of the Invention) As is clear from the above description, the present invention, when heating a powder alloy sheet to obtain a sintered metal layer as a wear-resistant layer, The lubricating oil recesses can be automatically formed as oil reservoirs and oil grooves in the hard sintered metal layer, resulting in a separate and difficult machining process to form the lubricating oil recesses in the hard sintered metal layer. becomes unnecessary.

[Brief explanation of drawings]

FIG. 1 is a side view showing a rocker arm equipped with a chip piece to which the method of the present invention is applied. FIGS. 2 and 3 are cross-sectional views sequentially showing the steps of the present invention. FIG. 4 is a plan view of FIG. 3. 3...Chip piece (metal base) 5...Sintered metal layer 6...Four parts for lubricating oil 7...Recessed part for sinking 8...Powder alloy sheet Patent applicant Toyo Kogyo Co., Ltd. Figure 2 Figure 3 11=-2≦4 Figure 4 Procedural amendment (voluntary) May 11, 1980 Mr. Commissioner of the Patent Office? Name of the invention Method for forming a wear-resistant sliding surface 3 Relationship to the amended case Name of patent applicant (313) Toyo Kogyo Co., Ltd. (and 1 other person) 4 Agents Address: 105-508-1801 Address Tokyo 3-7-3 Shinbashi, Minato-ku, Midoriya Building 2
Contents of amendment in column 6 of “Detailed Description of the Invention” (1) On page 9, line 6 of the specification, replace r300J with r1
Correct it to 50J. (2) On page 13, line 12, replace r200J with “1”.
50”. that's all

Claims (1)

[Scope of Claims] (1) On the surface of the metal base that requires wear resistance, a sinking recess is formed in a cylindrical position corresponding to a region where a recess for lubricating oil as an oil reservoir or oil groove is desired to be formed. a step of adhering a powder alloy sheet made of a mixture of wear-resistant alloy powder and a resin binder to the surface of the metal substrate; and heating the powder alloy sheet at a semi-liquid phase sintering temperature. A step of sinking wear-resistant alloy powder into the sinking recess to obtain a sintered metal layer as a wear-resistant layer in which the lubricating oil recess is exposed at a portion corresponding to the sinking recess. A method for forming a wear-resistant sliding surface characterized by: (2. In claim 1, the resin binder of the powder alloy sheet is an acrylic resin having pressure-sensitive adhesive properties at room temperature. (3) In claim 2, the powder The alloy sheet contains 3 to 15% by volume of an acrylic resin that has pressure-sensitive adhesive properties at room temperature as a resin binder, and 97 to 85% by volume of the wear-resistant alloy powder. The powder alloy sheet is bonded to the metal substrate by adhesive properties. (In claim 3, during the heating,
After being held at 150°C to 380°C for 5 minutes or more, the temperature is raised to the semi-liquid phase sintering temperature. (5) Any one of claims 1 to 4
2, wherein the wear-resistant alloy powder is a wear-resistant eutectic alloy powder.