JPS63140117A - Combination sliding member - Google Patents

Abstract

PURPOSE:To lessen a clearance change due to temperature by forming an 'Alumite(R)' layer on a sliding surface of one member of a pair of sliding members, the base metal of which is an aluminum alloy and a Cr plating layer on a sliding surface of the other member. CONSTITUTION:An aluminum alloy which can form an 'Alumite(R)' layer is processed on anode side by an electrolytic bath to obtain an 'Alumite(R)' layer forming member as one member. On the other hand, Cr plating layer is formed on the surface of the other member by electroplating. A difference in thermal expansion coefficient between both aluminum alloys which are base metals of a combination sliding portion is less than 3X10<-6>/ deg.C. When the combination sliding member is used in a piston type, a clearance change due to thermal expansion is very little so that stick is not caused.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a combination sliding member, and more particularly to a combination sliding member in which both base materials are made of an aluminum alloy (hereinafter abbreviated as "aluminum alloy"). It is.

(Prior Art) In order to reduce the weight of sliding members used in automobiles and the like, it is necessary to use an aluminum alloy as a base material.

By the way, what about the aluminum alloy itself?

It has the disadvantage of poor wear resistance when used as a sliding member. As a method to compensate for this drawback, it is known to form an alumite film on one surface by anodizing treatment ("Machine Design", Vol. 29, No. 15, 77-86).
Page, 1985). Due to the formation of this alumite film, the wear resistance is considerably improved even though the base material is an aluminum alloy.

However, if an alumite film is formed on both of a pair of combined sliding members, the same type of material will slide.
In fact, the combined sliding member made of an alumite film and an aluminum alloy base material has less wear.

Therefore, for conventional lightweight sliding members, the body side member is made of aluminum alloy with an anodized layer formed by anodizing, and the sliding member is made of wear-resistant steel or heat-treated @all valve side members. members are used.

(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 changes in the temperature of lubricating oil.

In other words, since the coefficient of thermal expansion is different between the body side (aluminum alloy and alumite layer) and the valve side (ferrous material),
At low temperatures, the clearance of the sliding parts becomes small, causing sticking (defective valve sliding), and at high temperatures, the clearance increases, causing oil leakage. Furthermore, when the valve is left to cool after being used at high temperatures, foreign matter in the lubricating oil circuit remains between the valve and the body, causing the problem of sticking.

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 anodized aluminum alloy for the valve side as well, and it is partially practical. has been made into

This combination does not cause problems due to the above-mentioned changes in clearance, but as mentioned above, there is a problem in that the alumite layers have poor wear resistance when sliding against each other.

By the way, as a method for improving the wear resistance of aluminum-based members, in addition to the above-mentioned anodizing treatment (alumitization), the following method is known.

■ Method of sharpening the surface by applying Fe (iron) plating (
"Plating Technology Handbook" published by Nikkan Kogyo Shimbun, 1936 & 7.25
(see first edition, page 270).

■ A method of applying electrical polishing to one aluminum alloy to form a KFe-P (iron-phosphorus alloy) plating film on the other aluminum alloy (see %Kai No. 58-146765); Il! ! A method of applying etching treatment (hereinafter referred to as rECM treatment) by depolishing or chemical polishing, and forming an Fe-P plating film in which 5iC (silicon carbide) particles, etc. are dispersed on the other aluminum alloy (Japanese Patent Laid-Open No. 1983-1999). -165389).

However, although these methods show some improvement effects, they are by no means satisfactory.

By the way, when using a high-silicon aluminum alloy (standard: A390), which has good wear resistance among aluminum alloys, the friction is caused by primary crystal silicon 7 (Hv 900) in the aluminum alloy structure.
~1100) and the mating material (Fe-plated material), the wear of the mating material increases, and as the surface roughness increases, the wear of both itself and the mating material increases. Furthermore, when used in a high load area, the same phenomenon as when primary silicon cracks or falls off and foreign matter enters occurs, and the seizure load decreases.

The present invention was made to solve the above problems,
The purpose is to provide a combined sliding member whose base material is made of aluminum alloy, which does not cause clearance changes due to temperature, and which is highly wear-resistant and anti-seizure. That's true.

(Means for solving problem "r") A combined sliding member of the present invention capable of achieving the above object is a pair of sliding members both made of aluminum alloy as a base material, the sliding surface of one member being An alumite layer is formed on the sliding surface of the other member, and a Cr (chromium) plating layer is formed on the sliding surface of the other member.

The present invention is based on the knowledge that, when combined as described above, it is possible to obtain a sliding member with significantly improved wear resistance and seizure resistance compared to the conventional ones, and will be explained in more detail below. .

One of the members, the alumite layer forming member, was prepared using a conventional method.
It is obtained by treating an aluminum alloy capable of forming an alumite layer on the anode side using an electrolytic bath, such as a sulfuric acid bath, an oxalic acid bath, or a mixed acid bath thereof. The hardness of this alumite film may be Hv150 or more. Below that, the alumite layer will rapidly wear out.

The C plating layer on the surface of the other member may also be electroplated by a conventional method, and the Cr plating layer is usually made of hard gH, considering the wear resistance and scratching resistance of itself and the mating material.
v400~900. The thickness is preferably 1 to 150μ, and the electrolytic plating solution concentration (chromic acid 170 to 2809/l, sulfuric acid α
7-1.1p) and 1! L flow density (20-95 k/dm
2) Such a Cr plating layer can be formed by appropriately selecting f.

The difference in thermal expansion coefficient between the two aluminum alloys that are the base materials of the combined sliding member of the present invention is preferably 5 x 10-6/"C: or less. If it exceeds this value, it will not be possible to use it at high temperatures (150°C). This is because foreign matter in the lubricating oil circuit remains between the body and the valve when it is cooled and tends to cause stick.
/'C or less, even if foreign matter remains, a slight scratch M will occur between the body and the valve, but no stick will occur.

Therefore, the wood combination sliding member is suitable as a piston-type sliding member, particularly as a combination sliding member for a body and a valve of an oil path switching device of an automatic transmission.

(Example) Examples of the present invention will be described below together with comparative examples, but the present invention is not limited thereby.

Example 1 A cylindrical piece with an outer diameter of 55 flm%, a circle diameter of 30 gourd, and a width of 10 wire was prepared using Al alloy (JIS standard Al) C12).Then, a sulfuric acid bath was applied to the outer peripheral surface of the cylindrical piece to form an anode. By applying oxidation treatment, it has a thickness of 10μ and hardness) lv3.
An inner cylinder test piece having a 00 oxide film (alumite layer) was prepared.

On the other hand, 16X6X10m aluminum alloy (iJ3 product (JI)
S standard ACIA) - Chromic anhydride bath (2sog/I
By plating at a current density of 60 A/dm2 and a bath temperature of 55°C, a thickness of 30 μm and hardness was obtained.
Has a Cr plating layer of lv700, 16mx6+mIf
A dice test piece with r as the test surface was prepared.

The dice test piece and the cylindrical test piece were combined and subjected to the following wear test.

Comparative Examples 1 to 5 Various combination test pieces in which one cylindrical test piece and the other dice test piece are made of the members shown in Table 1 (Comparative Examples 1 to 3)
was prepared and subjected to the following abrasion test in the same manner as in the examples.

1st Table Abrasion Test Each combination test piece of Example 1 and Comparative Examples 1 to 3 was set in the JP friction wear tester, and the outer peripheral surface of the 1-yen towel test piece and the 16 x 6 die test piece were in full contact with each other. Then, lubricating oil (ATF: trade name: "
A wear test was conducted in which the cylindrical specimen was rotated for 30 minutes at a load of 60 kg and a rotation speed of 60 rpm while supplying Dexron IIJ)'. The surface roughness of the cylindrical test piece and dice test piece is α8μRz and 1.2μ, respectively.
It is 几2.

The results of this wear test are shown in FIG. In the figure.

The upper half represents the amount of wear on the cylindrical test piece (71 mm weight loss IIv), and the lower half represents the amount of wear on the dice test piece (wear scar depth μ).

From Figure 1, the wear of the dice test piece without surface treatment is large in the combination (5) of Comparative Example 1 of alumite material and wrought aluminum material, and the combination of alumite materials in Comparative Example 2 (B) It can be seen that the wear of the cylindrical specimen increases. The combination of alumite material and Cr-plated material in Example 1 (to) is the same as the combination of alumite material and hardened steel in Comparative Example 3, even though the base materials are both aluminum alloys.
It can be seen from the comparison of the wear amount of the cylindrical test piece and the dice test piece that the wear resistance of QYOP is also low.

Example 2 and Comparative Examples 4 to 6 IJ in Table 1 as Example 2 and Comparative Examples 4.5 and 6, respectively.
, A, B, and C, all of which have an outer diameter of 25.4 cWL and an inner diameter of 20 questions.

A combined cylindrical test piece with long vomit and 10 pharynx was prepared and subjected to the following seizure test.

Seizure test example 2. The cylindrical end surfaces of the cylindrical test pieces of each combination of Comparative Examples 4.5 and 6 were brought into contact with each other, lubricating oil (trade name "Castle Motor Oil J5w-30") was supplied, and the rotation speed was adjusted to .OOrpm Table 2. The results are shown in Table 2.

As can be seen from Table 2, it was confirmed that the combined test piece of Example 2 had superior seizure resistance compared to those of each comparative example.

Example 3 and Comparative Examples 7.8 FIG. 2 shows a hydraulic switching device 51f4 built into an automatic transmission.

The valve body 1 was manufactured by anodizing using an aluminum alloy (JIS standard AL) C10)'i. In addition, the shift valves 2 are B, C, and D shown in Table 1.
It was made from the same material as the 3D type dice test piece. The hydraulic switching device 5 obtained by combining these valves 2 and the above body 1 was actually installed in the transmission of a vehicle, and the valve was operated for 90,000 cycles (ioOhr).
It was subjected to a durability test to compare the damage after operation. The outer diameter of the valve was set to 10mm, and the clear lath between the valve and body was set to 40mm.

The results are summarized in Table 8g3. Combination of alumite material and hardened steel of Comparative Example 8 (the one manufactured by q is 40
．． After operating the OOO cycle, a stick occurred and the valve stopped working. In addition, in the case of Comparative Example 7, which was manufactured using the combination of alumite materials (b), although sticking did not occur, both the body and the valve had significant wear. In comparison, the one manufactured using the combination (g) of alumite material and Cr plating material of Example 3 showed good results as seen from Table 3.

Table 3: Durability test results (effects of the invention) The combined sliding member of the present invention has twice the seizure resistance and 2 to 2 times more wear resistance than conventional sliding members made of a combination of aluminum alloys. It shows an extremely superior performance of 30 times.

Therefore, it can be used as a piston-type sliding member that is subjected to severe sliding conditions.

When used in a piston type, the base material of both combined sliding members of the present invention is aluminum alloy, so there is little change in clearance due to thermal expansion.

Does not cause stick.

Furthermore, it has better wear resistance and seizure resistance than aluminum alloy and steel combination sliding members, so wood combination sliding members can be used instead, contributing to weight reduction of sliding parts. .

[Brief explanation of the drawing]

The first figure 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. FIG. 2 is a diagram showing the groove arrangement of a piston-type sliding part of an oil passage switching device used in an automatic transmission. In the figure: 1...Valve body 2...Shift valve patent applicant Toyota Motor Corporation

Claims (4)

[Claims] (1) A pair of sliding members both made of aluminum alloy as a base material, with an alumite layer formed on the sliding surface of one member and a Cr (chromium) plating layer formed on the sliding surface of the other member. A combination sliding member characterized in that: (2) The combination sliding member according to claim 1, wherein one member is a body and the other member is a piston-type sliding member of a valve. (3) The combination sliding member according to claim 2, wherein the piston type sliding member is a body and a valve of an oil passage switching device of an automatic transmission. (4) Claims 1 and 2 characterized in that the difference in thermal expansion coefficient between the aluminum alloy of one member and the aluminum alloy of the other member is 5×10^-^6/°C or less. The combination sliding member according to item 1 or 3.