Swash plate and method of manufacturing the same

Abstract

A swash plate includes aluminum (Al) as a main component and 3545 wt % of zinc (Zn), 1.53.5 wt % of copper (Cu), 610 wt % of silicon (Si), 0.20.5 wt % of magnesium (Mg) and other inevitable impurities. A method of manufacturing the swash plate is also provided.

Claims

1. A swash plate having primary silicon particles, the swash plate comprising aluminum (Al) as a main component and 3545 wt % of zinc (Zn), 1.53.5 wt % of copper (Cu), 610 wt % of silicon (Si), 0.20.5 wt % of magnesium (Mg) and other inevitable impurities, and wherein the primary silicon particles have a size of 2030 m.

2. The swash plate of claim 1, further comprising 0.10.3 wt % of manganese (Mn).

3. The swash plate of claim 2, wherein iron (Fe) and manganese (Mn) are contained at a ratio of 3:1.

4. A swash plate having primary silicon particles, the swash plate comprising: aluminum (Al) as a main component; 3545 wt % of zinc (Zn); 1.53.5 wt % of copper (Cu); 610 wt % of silicon (Si); 0.20.5 wt % of magnesium (Mg); and 0.10.3 wt % of manganese (Mn), wherein iron (Fe) and manganese (Mn) are contained at a ratio of 3:1; and wherein the primary silicon particles have a size of 2030 m.

5. A method of manufacturing a swash plate according to claim 1, comprising melting an alloy composed mainly of aluminum (Al) and additionally of 3545 wt % of zinc (Zn), 1.53.5 wt % of copper (Cu), 610 wt % of silicon (Si) and 0.20.5 wt % of magnesium (Mg) and then performing casting.

6. The method of claim 5, wherein a sliding surface of the swash plate which comes into contact with a shoe of a piston is subjected to lubricative coating using nickel-fluorine electroless plating or copper or brass electroplating.

7. The method of claim 5, wherein a sliding surface of the swash plate which comes into contact with a shoe of a piston is subjected to lubricative coating using nanoresin coating or fluoropolymer coating.

8. The method of claim 5, wherein the casting is gravity casting or high-pressure casting.

9. The method of claim 5, wherein the casting is sand casting.

10. The method of claim 9, wherein a sliding surface of the swash plate which comes into contact with a shoe of a piston is subjected to lubricative coating using nickel-fluorine electroless plating or copper or brass electroplating.

11. The method of claim 9, wherein a sliding surface of the swash plate which comes into contact with a shoe of a piston is subjected to lubricative coating using nanoresin coating or Teflon coating.

12. The method of claim 9, wherein the casting is gravity casting.

13. A method of manufacturing a swash plate according to claim 1, comprising continuously casting an alloy composed mainly of aluminum (Al) and additionally of 3545 wt % of zinc (Zn), 1.53.5 wt % of copper (Cu), 610 wt % of silicon (Si), and 0.20.5 wt % of magnesium (Mg) in a form of a billet and then performing hot forging.

14. The method of claim 13, wherein a sliding surface of the swash plate which comes into contact with a shoe of a piston is subjected to lubricative coating using nickel-fluorine electroless plating or copper or brass electroplating.

15. The method of claim 13, wherein a sliding surface of the swash plate which comes into contact with a shoe of a piston is subjected to lubricative coating using nanoresin coating or fluoropolymer coating.

16. The method of claim 5, wherein the casting is mold casting.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an exemplary swash plate according to the present invention.

(2) FIG. 2 shows a fine structure of the swash plate of FIG. 1.

DETAILED DESCRIPTION

(3) Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims principles of the present invention.

(4) According to various embodiments of the present invention, the swash plate comprises Al as a main component and 3545 wt % of Zn, 1.53.5 wt % of Cu, 610 wt % of Si, 0.20.5 wt % of Mg and other inevitable impurities. The Si content of this Al alloy is different from that of conventional hyper-eutectic Al alloys, and specifically, Si is used in the remarkably lower amount of 610 wt % in the present invention compared to the hyper-eutectic alloy in which Si must exceed 12.6 wt %.

(5) Further, the swash plate may include 0.10.3 wt % of Mn so that the ratio of Fe and Mn is 3:1. Various tests proved that the alloy composition of the swash plate according to the present invention was optimal. When the swash plate has such an appropriate composition, all of the wear resistance, processability and lubricating properties which are required of swash plates can be ensured, as will be described later. Furthermore, such a swash plate made of the novel Al alloy has drastically improved performance compared to conventional swash plates.

(6) Specifically, the Si contained in the swash plate according to the present invention is added to induce the formation of fine primary Si particles having a size of 2030 m in order to increase wear resistance of the base metal. If the amount of Si is less than 6 wt %, primary Si particles are not produced. In contrast, if the amount of Si exceeds 10 wt %, primary Si particles become coarse, undesirably decreasing processability and wear resistance. When coarse Si particles are formed, hard particles may agglomerate, and wear resistance may instead deteriorate. Thus, the amount of Si in Al is preferably set to 610 wt %.

(7) In addition, Zn, which is the next most mainly added after Al, is used to form low-melting-point self-lubricative particles through phase separation with Al. When the low-melting-point self-lubricative particles are formed, the particles themselves function as a lubricating agent even at relatively low temperature, thus decreasing the resistance coefficient. If the amount of Zn added to form the low-melting-point self-lubricative particles is less than 35 wt %, self-lubricative properties may deteriorate. In contrast, if the amount of Zn exceeds 45 wt %, the specific gravity of the base metal may increase and mechanical properties may deteriorate. Hence, the amount of Zn is preferably set to 3545 wt %.

(8) In addition, Mg is added to produce a precipitation strengthening phase (MgZn.sub.2) through the reaction with Zn, and the precipitation strengthening phase is formed by reacting Mg and Zn, thereby enhancing the strength of the swash plate. If the amount of Mg is less than 0.2 wt %, strengthening effects become insignificant. When the amount of Mg is 0.5 wt %, the maximum strength can be obtained. Thus, the amount of Mg is preferably set to 0.20.5 wt %.

(9) As an additional element, Mn is added to prevent the production of acicular intermetallic compounds due to the Fe present as an impurity in the base metal. Specifically, the Fe contained as an impurity in Al forms an acicular compound after reacting with Al or Si. When Mn is further added in this way, the acicular shape of such a compound becomes dull. Thus, the amount of Mn is preferably set to 0.10.3 wt % to prevent the production of the acicular intermetallic compound in order to increase the strength and elongation of the swash plate. Also, Mn may be added in an amount of of the amount of Fe which is an impurity, so that Mn functions as above. Because Al typically contains 0.6 wt % of Fe impurity, the addition of Mn in an amount of 2.0 wt % is proved to be optimal.

(10) FIG. 1 shows the swash plate 100 according to the present invention, and FIG. 2 shows an electron microscope image of the fine structure of the swash plate. As shown in FIG. 2, the swash plate according to the present invention has a composite fine structure comprising hard particles composed of primary Si 10 and soft particles composed of Zn 20 and Al 30, thus exhibiting superior wear resistance and lubricating properties to the extent that this alloy may substitute for conventional Cu alloy.

(11) Also, unlike the conventional alloy, the alloy according to the present invention has a low liquidus temperature of about 500540 C., and thus there are almost none of the problems of the fine structure being increased in proportion to the cooling rate reduction. The swash plate according to the present invention may have superior properties even when mold casting (gravity, die casting) or sand casting is applied. Briefly, this plate is much less affected by the kind of process.

(12) Specifically, the method of manufacturing the swash plate according to the present invention comprises melting an alloy composed mainly of Al and additionally of 3545 wt % of Zn, 1.53.5 wt % of Cu, 610 wt % of Si and 0.20.5 wt % of Mg, and then performing mold casting, in which the casting may be either gravity casting or high-pressure casting.

(13) In addition, the method of manufacturing the swash plate according to the present invention may comprise melting an alloy composed mainly of Al and additionally of 3545 wt % of Zn, 1.53.5 wt % of Cu, 610 wt % of Si and 0.20.5 wt % of Mg and then performing sand casting. In this case, the casting process is gravity casting.

(14) In addition, the method of manufacturing the swash plate according to the present invention may comprise continuously casting an alloy composed mainly of Al and additionally of 3545 wt % of Zn, 1.53.5 wt % of Cu, 610 wt % of Si and 0.20.5 wt % of Mg in the form of a billet and then performing hot forging.

(15) Further, the sliding surface of the swash plate coming into contact with the shoe of the piston may be coated with metal or non-metal. The metal coating may be a lubricative coating using NiF electro less plating or Cu or brass electroplating, and the non-metal coating may be a lubricative coating resulting from coating the sliding surface coming into contact with the shoe of the piston with nanoresin or a fluoropolymer such as polytetrafluoroethylene (PTFE) (e.g., TEFLON).

(16) The following examples may provide a better understanding of the present invention, which are set forth to illustrate, but are not to be construed as limiting the present invention.

Example and Comparative Example

(17) In order to manufacture the swash plate, the swash plate material according to the present invention and an A390 continuous cast alloy were used in the example and comparative example, respectively. The component ratios are shown in Table 1 below.

(18) TABLE-US-00001 TABLE 1 Zn Si Cu Mg Fe Mn C. Ex. (A390) 18.2 3.4 0.3 0.06 Ex. 40.5 7.8 1.9 0.4 0.6 0.2

(19) The alloy of the example, composed mainly of Al and additionally of 40.5 wt % of Zn, 7.8 wt % of Si, 1.9 wt % of Cu, 0.4 wt % of Mg, 0.6 wt % of Fe and 0.2 wt % of Mn, was melted, after which the melted alloy was subjected to gravity casting using a mold and then processed, and then the surface thereof was electro less plated with NiF.

(20) On the other hand, the alloy (A390 continuous cast alloy) of the comparative example was composed mainly of Al and additionally of 18.2 wt % of Si, 3.4 wt % of Cu, 0.3 wt % of Mg, and 0.06 wt % of Fe. This alloy was subjected to continuous casting, T6 heat treatment, forging and then processing, after which the surface thereof was plated with Sn, thus manufacturing a swash plate sample.

Test Example

(21) The strength of the alloy of each of the example and comparative example was measured at room temperature using a tensile tester, and wear resistance thereof was measured using a reciprocal motion wear tester. Also, in order to check whether the alloy may be actually applied to products, the durability of a product simulating the driving conditions of a variable compressor was evaluated. The results are shown in Table 2 below.

(22) TABLE-US-00002 TABLE 2 Tensile Wear Resistance Strength Elongation (Friction Durability (Mpa) (%) Coefficient) Results C. Ex. 370 1.1 0.05 Fail (A390 Alloy) Ex. 390 1.5 0.04 Pass

(23) As is apparent from Table 2, the strength of the new alloy according to the present invention at room temperature was increased by 5% because of changes in fine structure, and wear resistance (friction coefficient) was reduced by 20%. According to the durability evaluation results, the Al swash plate of the present invention could be applied to variable air conditioning compressors, replacing conventional Cu alloy and cast iron.

(24) When the swash plate according to the present invention is applied to variable compressors in this way, the cost of thirteen billion five hundred million won per year can be reduced compared to when using conventional Cu alloy, and the weight can also be reduced by 66% (100 g/each). Furthermore, friction properties can be improved by 20% or more compared to conventional hyper-eutectic Al.

(25) As described hereinbefore, the present invention provides a swash plate and a method of manufacturing the same. According to the present invention, Al is added with excess Zn, Si and so on, thus forming a composite fine structure comprising hard particles (primary Si) and soft particles (Zn), thereby ensuring wear resistance equal to that of hyper-eutectic AlSi alloy, Cu alloy or cast iron.

(26) Also because the fine structure of the alloy is produced due to phase separation at about 500 C., it is not affected by a casting process or a cooling rate unlike hyper-eutectic Al alloy which needs rapid cooling or phosphorus (P) treatment. Thus, even when typical mold casting or sand casting having a low cooling rate is applied, wear resistance can be ensured.

(27) Also, because the fine structure comprising hard-soft particles is provided, in addition to wear resistance, superior lubricating properties can be attained compared to conventional wear resistant materials.

(28) The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.