JPH01188639A - Sliding member for rotary compressor - Google Patents

Abstract

PURPOSE:To obtain the lightweight subject member having fundamental characteristics similar to those of an iron material in a sliding member made of ceramic short fiber reinforced Al alloy by specifying the compsn. of the Al alloy, the components of the short fiber, the volume ratio of the fiber and the relationship between the above volume ratio and the Si amounts in the Al alloy. CONSTITUTION:The sliding member is formed from the short fiber reinforced Al alloy in which the Al alloy contg., by weight, 10-20% Si, 1-7% Cu and 0.2-0.8% Mg and the balance constituted of Al is charged and compounded to the short fiber molded body contg. Al2O3 and/or Al2O3-SiO2 short fiber and having 20-30% fibrous volume ratio % Vf. In the relationship between the fibrous volume ratio Vf and the wt.% of Si in the Al alloy Wt, >=40Vf+Wt is satisfied. In the use of said short fiber reinforced Al alloy as the title sliding member, low coefficient of thermal expansion and high wear resistance can be obtd. The sliding member furthermore has excellent bending strength and impact value and is more lightweight than the iron material, by which the rotary compressor having high capacity can be obtd.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a sliding member of a rotary compressor,
In particular, it relates to a sliding member for a rotary compressor made of an aluminum alloy composite-reinforced with short fibers.

(Prior art) Conventionally, sliding members of rotary compressors were made of SU.
Spring steel equivalent to G, wear-resistant castings, special steel equivalent to SKH, etc. were used, but recently, JP-A-6
0-50137, in which hard particles are dispersed in an aluminum alloy, a particle-dispersed aluminum alloy, and an aluminum alloy in which ceramic particles are dispersed, as disclosed in JP-A-62-30838. Materials reinforced with fibers and fibers have begun to be used.

(Problems to be solved by the invention) Rotary compressors are mainly used in the field of refrigerators, and as typified by air conditioners and car air conditioners, there is a strong demand for smaller, lighter, and more efficient rotary compressors. There is. Although sliding members made of iron-based materials have excellent strength, wear resistance, and low coefficient of thermal expansion necessary for sliding members,
The problem is that the compressor is inefficient due to its heavy weight and generates large vibrations. Aluminum alloys, on the other hand, have the characteristic of being lightweight, but the mechanical properties required for sliding members cannot reach the level of iron-based materials.In particular, they have a large coefficient of thermal expansion, making it difficult to set clearances, and There is also a problem that abrasion resistance is poor. JP-A-60-50137 and JP-A-6 as a means to solve the drawbacks of aluminum alloys
Si, N4 and 5 as disclosed in 2-30838.
The method of dispersing ceramic particles such as iO7 in an aluminum alloy requires a complex multi-step process including preforming of the powder, sintering in a vacuum or in an inert gas atmosphere, and extrusion molding. The expansion coefficient is also 18.8 x 10-6
C. -1, it is not as good as iron-based materials, it is necessary to add Fe or Ni to further lower the thermal expansion, and there are problems in that it cannot reach the required level of wear resistance.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention aims to solve the above-mentioned problems by weight percentages of Si: 1 (1 to 20%, Cu: 1 to 7%, Mg: 0.
An aluminum alloy with 2 to 0.8% balance essentially AA is 8β203. An20. -5iO The present invention provides a high-performance sliding member that has excellent wear resistance and satisfies the bending strength and impact value levels required for sliding parts for rotary compressors. Furthermore, the present invention provides a sliding component made of a fiber-reinforced aluminum alloy in which the weight percentage Wt of Si and the volume percentage Vt of short fibers in the aluminum alloy are in the range of 40≦Wt→-V. The reason for limiting the aluminum alloy component range is that lIIg is effective in improving strength, but 0.2
% or less, the effect is small, and if it exceeds 0.8%, the decrease in toughness becomes noticeable, so it was set to 0.2% to 0.8%. Cu has solid solution strengthening and A j! Precipitation strengthening of 2Cu contributes to strength, but if it is less than 1%, the effect of solid solution strengthening is small, and if it is more than 7%, the A j22C11 precipitates become coarse and the toughness decreases, so the content should be in the range of 1 to 7%. Limited. Next, the Si component range wt: 10 to 20%, the fiber volume percentage of the molded body VflO to 30%, and Wt
The reason for the limitation of Vf≧40 is that when vf is 30% or more, the formability of the molded body is poor, the aluminum filling property is poor, and the cost of the molded body is also high, so Vf was set to 30% or less. On the other hand, in order to obtain a thermal expansion coefficient of 13.5×10 −6° C. −8 or less necessary for a sliding member when Vf is 30% or less, the weight percentage Wt of Si must be 10% or more. In addition, the reason why the upper limit of Si weight percent Wt was limited to 20% is that when Wt exceeds 20%, the melting point increases, and it is difficult to fill and composite the primary crystal S1 that crystallizes due to the drop in temperature during casting into a molded body. Therefore, Wt was set to 20% or less. At this time, the fiber volume fraction Vf of the molded body needs to be 20% or more, and if it is less than 20%, a member having the required low coefficient of thermal expansion cannot be obtained. In other words, in order to obtain a sliding member that has a low coefficient of thermal expansion, which is an essential property for a sliding member, and has good moldability, fillability, and castability, the fiber volume fraction percentage Vf of the short fiber molded product should be set to 20 to 20. 30%,
Weight percentage of Si.

It is necessary to limit V to 10 to 20% and to set V, +Wt≧40.

(Example) A E with a volume ratio of 5 to 35% 20. , - Short fibers of SiO2 were formed into a size of 50 x 80 mm and a thickness of 12+U, and this formed body was held in a mold installed in a 100T molten metal forging machine. Next, Cu: 4%, Mg: 0.6% were fixed, and S
Four types of aluminum alloys with different weight percentages of i from 7 to 20% were poured into a 60φ sleeve and a pressure cuff was placed.
00 kgf/cn! , plunger speed 20mm/s
The molded body is then injected and filled with aluminum alloy.
A fiber composite aluminum alloy member was cast.

At this time, Si Mini Full 20. Cu: 4%, Mg:
Using 0.6% aluminum alloy, cast members of the same size were made, solution heated at 500°C for 8 hours, and aged at 180°C.
The thermal expansion coefficients of two types of members subjected to the same heat treatment for 4 hours were compared. Figure 1 shows A (l z03
It is a diagram showing the fiber volume fraction of 5tOz short fibers and the coefficient of thermal expansion at 25 to 100°C, and the coefficient of thermal expansion of the sliding component according to the present invention is 13.5XIO-6°c-1 or less, which is less than 12X10-1 of cast iron. It can be seen that the value is close to '°C-1. On the other hand, the thermal expansion coefficient of an aluminum alloy not composited with short fibers is 17.5 x 10-6°C-1 or more, and cannot be used practically as a sliding member. Figure 2 is a diagram showing the influence of Wt and the fiber volume fraction percentage vf of the fiber molded article on the coefficient of thermal expansion when the weight percentage Wt of Si is changed to 7°10.17.20%. , is 20-3
0%, Wt is 10 to 20%, and within the range of vr +wt≧40, the coefficient of thermal expansion is smaller than 13.5×10−6°C−1, and it can be used as a sliding member.

In addition, the sliding member of the present invention has a bending strength of 50 kgf/Tsuru" or more, an impact value of 10 kgf-cm/c1 or more, and a Young's modulus of 80.
It has become possible to provide a high-performance sliding member for a rotary compressor, which has characteristics of 00 kg f/m 2 or more and hardness H, 890 or more.

(Effect) Si: 10~20%, Cu: 1~7%, Mg: 0.2~
An aluminum alloy with β of 0.8% and the remainder to the
A 201+ Aj! By using a short fiber reinforced aluminum alloy containing at least one of 203SiO□ and composited with a short fiber molded body having a fiber volume ratio of 20 to 30% as a sliding member for a rotary compressor,
It has a low thermal expansion coefficient and high abrasion resistance that are close to those of iron-based materials as basic properties, and also has excellent bending strength and impact values.Furthermore, it has a sliding member that is lighter than iron-based materials, so it can achieve high performance. Rotary compressor can be provided.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are diagrams showing the influence of the weight percent of Si (wt) and the fiber volume fraction percent vf of the short fiber molded article on the coefficient of thermal expansion.

Claims (1)

[Claims] (1) A sliding member used in a rotary compressor, with weight percentages of Si: 10-20%, Cu
: 1 to 7%, Mg: 0.2 to 0.8%, and the balance is substantially Al.
_3-A short fiber formed body containing at least one type of SiO_2 short fibers, having a fiber volume percentage V_f of 20 to 30%, and satisfying V_f+W_t≧40 in relation to the weight percentage W_t of Si in the aluminum alloy. A sliding member for a rotary compressor, characterized in that it is made of a short fiber-reinforced aluminum alloy filled with composite materials.