JPH0543798B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a combination sliding member, and more specifically, one member is made of an aluminum alloy (hereinafter referred to as "aluminum alloy").
), the other member is made of Niresist cast iron. [Prior Art] In order to reduce the weight of sliding members used in self-splitting cars and the like, aluminum alloys are required to be used as the base material. However, aluminum alloy itself has a drawback of poor wear resistance when used as a sliding member. As a way to compensate for this drawback, it is known to form an alumite film on the surface by anodizing ("Mechanical Design" Vol. 29, No. 15).
No. 77-86, 1985). Products with this alumite film formed (hereinafter referred to as "anodized materials")
Although the base material is aluminum alloy, the wear resistance is considerably improved. However, if both of a pair of combined sliding members are made of alumite material, the same type of material will be sliding, resulting in more wear.In fact, a combined sliding member made of alumite material and aluminum alloy will wear more. Less is. As mentioned above, aluminum alloy has poor wear resistance, so conventional lightweight sliding members, such as piston type, use aluminum alloy as an anodized material, which is anodized, as the body side member. A combination sliding member is used in which the valve side member is made of steel or heat-treated steel that has excellent properties. [Problems to be Solved by the Invention] However, when the combined sliding member is used in a piston type, the following problems occur due to temperature changes in the lubricating oil. In other words, because the coefficient of thermal expansion is different between the body side (aluminum alloy + alumite layer) and the valve side (iron-based material), the clearance of the sliding parts becomes smaller at low temperatures, causing stagnation (valve sliding failure). There was also the problem that the clearance became large at high temperatures, causing oil leakage. Furthermore, when the valve is left to cool after being used at a high temperature, foreign matter in the lubricating oil circuit remains between the valve and the body, causing a problem. As a countermeasure, it is of course best to use materials with the same coefficient of thermal expansion as possible for both the body side and the valve side.For this reason, it is possible to use an anodized aluminum alloy for the valve side as well. has been made into Although this combination does not cause problems due to the above-described changes in clearance, etc., there is a problem in that the alumite layers have poor abrasion resistance when sliding against each other as described above. Therefore, as an alternative method, it has been proposed to apply various types of plating to aluminum alloys in order to improve wear resistance (``Plating Technology Handbook'', 1st edition, p. 270,
46.7.25 Published by Nikkan Kogyo Shimbun, 1983-
146763, JP-A-60-165389), but no satisfactory effect has been obtained. The present invention was made to solve the above-mentioned problems, and its purpose is to be lightweight, have excellent wear resistance, and seizure resistance, and to prevent clearance changes due to temperature even when used in a piston type. It is an object of the present invention to provide a combination sliding member that does not require any combination of sliding members. [Means for Solving the Problems] In the combined sliding member of the present invention that can achieve the above object, one member is made of an aluminum alloy (alumite material) having an alumite layer on the sliding surface, and the other member is made of Niresist. It is characterized by being made of cast iron. One of the parts, the alumite material, is made using the usual method.
Aluminum alloy that can form an alumite layer is placed in an electrolytic bath,
For example, it can be obtained by treatment on the anode side using a sulfuric acid bath, an oxalic acid bath, a mixed acid bath of these, or the like. The hardness of this alumite layer should just be Hv150 or more. Below that, the alumite layer will rapidly wear out. The other member, Niresist cast iron (contains a large amount of Ni and becomes austenitic), has a linear expansion coefficient within the range of the linear expansion coefficient of the mating alumite material, 5 x 10 _- ⁶ /℃. It is important to choose. If the linear expansion coefficient difference with the alumite material is 5 x 10 ^-6 /℃ or more, and if the piston type is used at high temperature (150℃) and left to cool, foreign matter in the lubricating oil circuit may remain between the body and the valve and cause the stay. This is because at temperatures below 5×10 ^-6 /°C, even if foreign matter remains, it will cause some scratch marks between the body and the valve, but no stick will occur. The composition of such Niresist cast iron is C: 2.7 to 3.3%, Si: 2 to 4%, Mn: 0.8 to 1.5.
%, Ni: 13-22%, Cr: 1.75-6.0%, Cu: 0-
It is sufficient if it consists of 7% Fe and the balance is Fe. The combined sliding member of the present invention has good wear resistance and seizure resistance, and has very little change in clearance due to temperature, so it is suitable for use as a piston-type sliding member, especially in oil passage switching devices of automatic transmissions. It is suitable as a combined sliding member for a body and a valve. [Example] Examples of the present invention will be described below together with comparative examples, but the present invention is not limited thereby. Example 1 Aluminum alloy (JIS standard ADC12; linear expansion coefficient 21×
10 ^-6 /℃) and the size is 35 mm in outer diameter and 30 mm in inner diameter.
A cylindrical specimen with a thickness of 10μ and a hardness of Hv300 (alumite layer) was created by creating a cylindrical piece with a width of 10mm and anodizing the outer circumferential surface using a sulfuric acid bath. did. On the other hand, the size of the mating member is 16mm x 16mm x 10
mm Niresist cast iron dice test pieces were prepared. The Niresist cast iron used here is C: 3.0
%, Si: 3.0%, Ni: 15.0%, Cu: 4%, Cr: 3
%, Mg: 0.04%, the balance is Fe, and its linear expansion coefficient is 19.0×
10 ^-6 /℃. The Niresist cast iron dice test piece and the alumite cylindrical test piece were combined and subjected to the wear test described below. Comparative Examples 1 to 3 Aluminum wrought material (JIS standard A6063; linear expansion coefficient
^23.4
Hv400) and steel (JIS standard
Example ¹
It was combined with the same cylindrical test piece as above and subjected to the wear test described below. The members of the combination test pieces of Comparative Examples 1 to 3 and Example 1 are summarized in Table 1 for easy understanding.

[Table] Wear test Each combination test piece of Example 1 and Comparative Examples 1 to 3 was set in a friction and wear tester in sequence, and the outer peripheral surface of the cylindrical test piece was brought into contact with the 16 mm x 16 mm surface of the dice test piece. While supplying lubricating oil (ATF: trade name "Dexron") at a temperature of 25℃ to the contact area of the pieces, the cylindrical test piece was heated for 30 minutes at a load of 60 kg and a rotation speed of 160 rpm.
A wear test was conducted by rotating for minutes. The surface roughness of the cylindrical test piece and the dice test piece are respectively
They are 0.8μRz and 1.2μRz. The results of this wear test are shown in FIG. In the figure, the upper half represents the wear amount (wear loss mg) of the cylindrical test piece, and the lower half represents the wear amount (wear scar depth μ) of the dice test piece. From FIG. 1, it can be seen that the aluminum wrought material without surface treatment (the dice test piece A) has a large amount of wear, and the combination B of alumite materials has a large wear of the cylindrical test piece. It can be seen from the comparison of the wear amount of the cylindrical test piece and the dice test piece that the combination D of the alumite material and Niresist cast iron of Example 1 is not inferior to the combination C of the alumite material and hardened steel of Comparative Example 3. Example 2 Two types of cylindrical test specimens were prepared, one made of aluminum alloy with an alumite layer formed on the surface and the other made of Niresist cast iron, each with an outer diameter of 25.4 mm, an inner diameter of 20 mm, and a length of 10 mm. The combination was subjected to the following seizure test. In addition, these materials are the same as combination D in Table 1. Comparative Examples 4 to 6 Comparative Examples 4, 5, and 6 are A and B in Table 1, respectively.
A combination cylindrical test piece made of the same material combination as and C, each having an outer diameter of 25.4 mm, an inner diameter of 20 mm, and a length of 10 mm, was prepared and subjected to the following seizure test in the same manner as in Example 2. Seizure test The cylindrical end surfaces of the cylindrical test pieces of each combination of Example 2 and Comparative Examples 4 to 6 were brought into contact with each other, and lubricating oil (trade name "Castle Motor Oil" 5W-30) was supplied.
The rotation speed is 1000rpm and the pressing load is 700 from 10Kg.
A seizure test was conducted to measure the maximum seizure load by increasing the load in stages up to Kg. The results are shown in Table 2.

[Table] As can be seen from Table 2, it was confirmed that the samples according to the examples had better seizure resistance than those of the comparative examples. Example 3 and Comparative Examples 7 and 8 FIG. 2 shows a hydraulic switching device 3 built into an automatic transmission. The valve body 1 was manufactured by alumite treatment using an aluminum alloy (JIS standard ADC10). In addition, the shift valve 2 is B shown in Table 1,
It was made of the same material as the three types of dice test pieces C and D. The hydraulic switching device 3 obtained by combining these valves 2 and the above body 1 is actually installed in the transmission of a vehicle, and the valve
A durability test was conducted to compare the damage after 90,000 cycles of operation (100 hours of operation). In addition, the outer diameter of the valve
Valve and body clearance at 10mm and 20℃
It was set to 40 μm. The results are summarized in Table 3. In the case of Comparative Example 8, which was manufactured using combination C of anodized aluminum and hardened steel, the valve became stuck and stopped working after 40,000 cycles of operation. In addition, in Comparative Example 7, which was manufactured using combination B of alumite materials, although no sticking occurred, both the body and the valve suffered significant wear. In comparison, Example 3
As can be seen from Table 3, the product manufactured using combination D of anodized aluminum material and Niresist cast iron showed good results.

〔Effect of the invention〕

The sliding member of the present invention has approximately twice the seizure resistance and approximately 8 times the abrasion resistance of the conventional sliding member made of a combination of aluminum alloys (one of which was anodized), and the wear resistance of both parts is approximately 8 times. Shows excellent performance. In addition, it has superior wear resistance and seizure resistance compared to sliding members made of a combination of aluminum alloy and steel, and the difference in linear expansion coefficient between the two members is smaller than that of conventional sliding members. Therefore, when used in a piston type, the combined sliding member of the present invention undergoes little change in clearance due to thermal expansion and does not generate stuck. This has the effect of significantly improving the durability of piston-type sliding parts that are subjected to severe sliding conditions.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the wear test results of the combined sliding member of the example of the present invention in comparison with that of the comparative example, and Fig. 2 is a diagram showing the results of a wear test of the combined sliding member of the example of the present invention, and Fig. 2 is a diagram showing the results of the abrasion test of the combined sliding member of the example of the present invention. FIG. In the diagram, 1... valve body, 2... shift valve.

Claims (1)

[Scope of Claims] 1. A combination sliding member characterized in that one member is made of an aluminum alloy having an alumite layer on the sliding surface, and the other member is made of Niresist cast iron. 2 The difference in linear expansion coefficient between the aluminum alloy of one member and the Niresist cast iron of the other member is 5 × 10 ^-6 /
The combination sliding member according to claim 1, characterized in that the temperature is below .degree. 3. The combination sliding member according to claim 1 or 2, wherein one member is a body and the other member is a piston-type sliding member of a valve. 4. Claim 3, characterized in that the piston-type sliding members are the body and valve of an oil passage switching device of an automatic transmission.
Combination sliding member described in Section 1.