US20010037845A1 - Piston for swash-plate type compressor and manufacturing method of the same - Google Patents

Piston for swash-plate type compressor and manufacturing method of the same Download PDF

Info

Publication number
US20010037845A1
US20010037845A1 US09/823,879 US82387901A US2001037845A1 US 20010037845 A1 US20010037845 A1 US 20010037845A1 US 82387901 A US82387901 A US 82387901A US 2001037845 A1 US2001037845 A1 US 2001037845A1
Authority
US
United States
Prior art keywords
piston
manufacturing
molten metal
treatment
swash
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US09/823,879
Other languages
English (en)
Inventor
Takayuki Kato
Masato Takamatsu
Seiji Katayama
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Industries Corp
Original Assignee
Toyoda Jidoshokki Seisakusho KK
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyoda Jidoshokki Seisakusho KK filed Critical Toyoda Jidoshokki Seisakusho KK
Assigned to KABUSHIKI KAISHA TOYODA JIDOSHOKKI SEISAKUSHO reassignment KABUSHIKI KAISHA TOYODA JIDOSHOKKI SEISAKUSHO ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KATAYAMA, SEIJI, KATO, TAKAYUKI, TAKAMATSU, MASATO
Publication of US20010037845A1 publication Critical patent/US20010037845A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
    • F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
    • F04B27/0873—Component parts, e.g. sealings; Manufacturing or assembly thereof
    • F04B27/0878—Pistons

Definitions

  • This invention relates to a manufacturing method of piston for a swash-plate type compressor and a piston manufactured by the manufacturing method.
  • a swash-plate type compressor is mainly used for an air conditioner of a vehicle. It is classified into a single-headed piston type and a double-headed piston type, or a fixed-capacity type and variable-capacity type, depending on construction thereof.
  • a variable-capacity type swash-plate compressor of a single-headed piston type is shown in FIG. 1, and a single-headed type piston constituting the swash-plate compressor is shown in FIG. 2.
  • a drive shaft 1 is supported at both axial ends thereof by a cylinder block 2 and a front housing 3 via bearings.
  • An axially intermediate portion of the drive shaft 1 is disposed in a crank chamber 4 formed by the cylinder block 2 and the front housing 3 .
  • plural bores 5 are formed around the axial end of the drive shaft 1 to receive single-headed type pistons 6 reciprocately.
  • a swash plate 8 is fitted to the drive shaft 1 behind a rotor 7 fixed to the drive shaft 1 .
  • the piston 6 is comprised of a cylindrical main body 6 a and a L-shaped shoe receiving portion 6 b formed at one end of the main portion 6 a.
  • the swash plate 8 is supported on the drive shaft 1 to be inclinable with respect to the drive shaft. Inclination angle of the swash plate 8 is controlled by balance of gas pressure acting on both end surfaces of the pistons 6 due to pressure change in the crank chamber 4 .
  • a flat engage (slidable-contact) surface 8 a formed on an outer periphery of the both end surfaces of the swash-plate 8 shoes 9 are abutted. Each of the shoes 9 engages with a semi-spherical surface 6 c formed on the shoe receiving portion 6 b .
  • the pistons In view of demand for lightening when the swash-plate type compressor is used in the vehicle air conditioner, in addition to the cylinder block, the pistons have been made of an aluminum alloy by a forging method or a casting method. Since the engage surfaces between the pistons and the shoes are put under severe sliding condition, good wear-proof character as a mechanical characteristic is demanded for the pistons. In view of this, the casted article have been subjected to a solution treatment and an artificial ageing treatment thereafter to increase the wear-proof character.
  • solution treatment means a quench treatment of a blank material after heated up to temperature in a range of solid solution for a constant time period.
  • artificial ageing treatment means a natural cooling of the blank material after heated up to 200° C. and held in this condition for a predetermined time period.
  • the mechanical characteristic of the casted article especially the wear-proof character in the manufacturing of the piston for swash-plate type compressor
  • an eutectic Si phase Si crystal in eutectic composition
  • a Al—Si alloy mainly used as the aluminium alloy has changed to a needle shape after casted to deteriorate the mechanical characteristic of the Al—Si alloy.
  • the needle-shape eutectic Si phase changes to spherical shape by the solution treatment to improve the mechanical characteristic of the Al—Si alloy, especially the wear-proof character.
  • the present invention intends to provide a manufacturing method of a piston for a swash-plate type compressor and the piston manufactured by this manufacturing method, which is excellent in the wear-proof character, in which blister is not generated, and which manufactures the piston by low cost, without the solution treatment after the die casting.
  • a manufacturing method of a piston for a swash-plate type compressor comprises a molten metal treating step including at least adding treatment for adding Na and/or Sr by 20 to 1000 ppm to a Al—Si alloy molten metal including Si of 7 to 18 wt %, and a die casting step for die casting the Al—Si alloy molten metal.
  • the manufacturing method of the piston for the swash-plate type compressor of the present invention adopts a die-casting method especially a pressure die-casting method, as the casting method. This is because the pressure die-casting method is suitable for a mass production and can manufacture the casted article having a smooth casted surface, thereby having high utilizing valve.
  • the molten metal treating step adding at least one of Na and Sr to a molten metal is performed before the die casting.
  • the molten metal treating step is used in a sand mold casting method etc. to fine the eutectic Si phase.
  • the eutectic Si phase not subjected to the fining treatment, has the needle shape in the composition after having been casted. However, it can be fined in the composition after the casting by the eutectic Si phase fining treatment. Fining of the eutectic Si phase can increase the mechanical characteristic of the casted article, especially an extending character and resisting value against shock.
  • the molten metal treating step in the manufacturing method of the piston of the present invention is performed, not to fine the eutectic Si phase but to sphere it.
  • Sphering of the eutectic Si phase by the molten metal treating step by adding at least one of Na and Sr to the molten metal has been found out by inventors of the present invention through repeated experiments. It can be confirmed on a composition photograph to be explained later. However, a mechanism in which the eutectic Si phase is sphered has not been clarified at present, unfortunately.
  • the eutectic Si phase in the Al—Si alloy can be sphered by addition of Na and/or Sr.
  • the composition is hardly broken because of no stress concentrated portions being existed.
  • the piston for the swash-plate type compressor which is excellent in the wear-proof character and in which the blister is not generated, can be manufactured by the low cost.
  • Si is included in the aluminum alloy for the die casting since it can perform improvement of the casting characters such as improvement of fluidity of the molten metal, decrease of heat expansion, decrease of hot crack, and decrease of shrinkage in the casting.
  • AD1, AD3, Ad10, AD10 z and AD12 etc. defined in JIS (Japanese Industrial Standard) H2118, or equivalents thereof can be used. From aspect of workability and tenacity, the Al—Si alloy including Si of 7 to 12 wt % is especially preferable.
  • the manufacturing method of the present invention can manufacture the piston for the swash-plate type compressor by a melting step for melting the base metal, a molten metal treating step for adding Na etc. to the molten base metal, and a die casting step. Further, an artificial-age treating step and a post treating step can be selectively performed. Next, each of the steps will be explained sequentially.
  • the melting step melts the base metal by a suitable melting method generally used in the melting of the aluminum alloy.
  • the aluminum alloy can be melted in a crucible furnace or an inducing furnace in a melting temperature of 670° to 710° C.
  • the molten metal treating step includes, in addition to a degassing treatment and a dreg-removing treatment, the adding treatment for addition of Na etc., that is, the sphering treatment to sphere the eutectic Si phase.
  • the degassing treatment is performed to reduce hydrogen gas amount in the molten metal which may cause porosity of the casted article.
  • an inert gas such argon and nitrogen generally used can be blown into the molten metal.
  • the dreg-removing treatment is performed to remove an intervening materials such as oxide etc. which may deteriorate casting character and reduce mechanical characteristics of the casted article.
  • a float separating method performed by blowing in inert gas and a flux treatment generally used can be adopted.
  • the sphering treatment of the eutectic Si phase which is the most remarkable feature of the present invention, is performed by adding at least one of Na and Sr to the molten metal.
  • Na is preferably selected.
  • Sr is preferably selected. Na or Sr can be added to the molten metal independently, or both of them can be added simultaneously.
  • the adding method of Na is not limited, but that generally used in the sand mold casting method can be used.
  • the flux including a metal Na, or NaF or NaCl is pressed into the molten metal by phosphorizer etc. and is agitated.
  • a tablet type flux floated on surface of the molten metal can be used.
  • the second method is preferably adopted.
  • the adding method of Sr is not limited, but that generally used in the sand mold casting method can be used.
  • a Al—Sr mother alloy can be put into the molten metal.
  • the added amount at least one of Na and Sr is added to the molten metal to be contained by 20 to 1000 ppm (here, ppm means wt. ppm) in the molten metal treating step.
  • ppm means wt. ppm
  • sum of both of the added amount of Na and the added amount of Sr should be selected in range of 20 to 1000 ppm. If the added amount is smaller than 20 ppm, due to small sphered rate of the eutectic Si phase, sufficient treating effect can not be obtained. To the contrary, when the added amount is larger than 1000 ppm, not only fluidity of the molten metal during the casting deteriorates but lifetime of the furnace is shortened due to corrosion.
  • at least one of Na and Sr is preferably added to be contained by 30 to 150 ppm before the die casting step.
  • Na and/or Sr wear by oxidation, so that the treating effect by them decreases as lapse of time.
  • Na and/or Sr are preferably supplemented into the molten metal to be contained by 20 to 1000 ppm in the molten metal treating step and before the die casting step. Excessive addition of Na may deteriorate the eutectic composition, so the max. amount of Na should be selected below 150 ppm.
  • Sphering of the eutectic Si phase is preferably performed so that particle of the eutectic Si phase has an average particle diameter of 1.5 to 3.0 ⁇ m.
  • the pressure die-casting step pours the molten metal into a mold in high speed under high pressure, and coagulates the poured-in molten metal rapidly to manufacture the casted article.
  • a casting apparatus and casting conditions generally used can be adopted.
  • the casting apparatus a cold chamber pressure die-casting machine can be used for example, and the casting conditions such as casting pressure of 20 to 100 MPa, gate speed of 40 to 80 m/s and filling time period of 5 to 100 sec. can be adopted.
  • the artificial-age treating step selectively performed heats the casted article in relatively low temperature of 200° C. or the therearound, and hold it in this condition for the constant time period, and then naturally cools it.
  • This artificial-age treating step is performed to further increase strength and dimensional stability of the casted article.
  • process generally used can be adopted.
  • the casted article heated in 90 to 210° C. and held for few hours can be naturally cooled.
  • the manufacturing method of the present invention preferably includes the artificial age treating step, in addition to the above mentioned molten metal treating step and the pressure die-casting step.
  • the casted article such as the piston of this embodying mode having been subjected to the artificial-age treating step after the casting is represented by “T5” in the refining mark (JIS H 0001).
  • the casted article subjected to the solution treatment before the artificial-age treating step is represented by “T6” in the refining mark (JIS H 0001).
  • the manufacturing method of the present invention can omit the artificial-age treating step.
  • the post treating step performs a machining of predetermined parts of the casted article and a surface treatment such as plating.
  • a surface treatment such as plating.
  • process generally used can be adopted.
  • the surface treatment a fluorocarbon resin film can be formed on an engage surface of the piston with the bore, and Sn can be plated on a receiving seat surface for shoe of the piston.
  • the piston manufactured by the above manufacturing method has a cylindrical main body and a shoe receiving portion. It maintains composition of the aluminum alloy including Si of 7 to 18 wt % as the base metal. In addition to Si, Cu, Mg, Zn and Fe etc. can be included. Also, the piston, having been manufactured through the molten metal treating step, includes added Na and/or Sr of 20 to 1000 ppm. In the micro composition, the eutectic Si phase is sphered to be explained later. That is, the eutectic Si phase is removed edges thereof to have round shape, which results in increase of mechanical characteristics, especially wear-proof character.
  • the wear-proof character is related to shape of the eutectic Si phase in the alloy composition. That is, the eutectic Si phase having the needle shape in the alloy composition of the piston, if stress is applied to the piston, is formed stress concentrated portion at both ends thereof and is opened at a central portion. This is same as state where crack is generated in the alloy composition. With further stress being applied, the opening extends to break the composition. Especially, if the needle-shape eutectic Si phase exists in the surface of the piston, the opening extends by small stress, so that the composition breaks remarkably by friction on the surface. In this way, the wear-proof character of the piston deteriorates.
  • the sphered eutectic Si phase preferably has an average particle diameter of 1.5 to 3.0 ⁇ m.
  • FIG. 1 is a longitudinal-section view of a single-headed and capacity-variable type swash-plate compressor
  • FIG. 2 is a front view of a single-headed type piston used in the above swash-plate type compressor
  • FIG. 3( a ) is a photograph showing an alloy composition of the piston manufactured with sphering of the eutectic Si phase
  • FIG. 3( b ) is a photograph showing an alloy composition of the piston manufactured without sphering treatment of the eutectic Si phase
  • FIG. 4 is an explanatory view showing measuring position of worn amount of the piston.
  • FIG. 5 is a graph showing measured result of worn amount of the piston.
  • Pistons are manufactured by the manufacturing method of present invention and that of the different manufacturing method. They are tested for examining wear-proof character. Detail of the piston, wear-proof test, evaluation based on tested results, and observed result of the alloy composition will be explained.
  • a piston of an embodiment has been manufactured according to the present invention in the following manner.
  • Al—Si alloy including Si of 12 wt % which corresponds to AD12 defined in JIS H 2118 is used as the base metal.
  • Chemical components of the Al—Si alloy is shown in a following Table 1. TABLE 1 Si Cu Mg, Zn, Fe Mn, Ni Al 12.0 3.0 to 5.0 each below 1.0 each below 0.5 Rest
  • the Al—Si alloy is melted in the crucible furnace at the melting temperature of 680 to 700° C. for the melting time period of 2 hours.
  • the degassing treatment, dreg-removing treatment and adding (sphering) treatment of the eutectic Si phase are performed, as the molten metal treating step. That is, the flux treatment contributing to both of the degassing treatment and the dreg-removing treatment is performed.
  • the sphering treatment of the eutectic Si phase only Na is added in 1 hour to the tablet (which is marketed as “Prima Pack”, by JAPAN METAL AND CHEMICAL”) floated on the molten metal.
  • Adding amount of Na is controlled to be contained by 100 ppm in the molten metal before the casting.
  • a cold chamber pressure die-casting apparatus is used for the pressure die-casting under casting pressure of 200 to 250 MPa.
  • the artificial-age treating step is performed to heat the casted article having been casted up to 200° C., and to naturally cool it after holdings for 1 hour.
  • the piston 6 is machined at the predetermined portions and is subjected to the surface treatment such as the plating etc.
  • This piston is comprised of the cylindrical main portion 6 a and the shoe receiving portion 6 b , and corresponds to the piston subjected to the treatment represented by “T5” in the refining mark (JIS H 0001) defined in JIS.
  • the manufacturing method of a piston of a comparative sample 1 differs from that of the piston of above embodiment, only in a molten metal treating step being performed without the sphering treatment of the eutectic Si phase. That is, the piston is manufactured by subjecting a molten base metal same as that of the embodiment to a molten metal treating step including only the degassing treatment and the dreg-removing treatment, pressure die-casting step, artificial-age treating step and post treating step. Conditions of the metal step, pressure die-casting step, artificial-age treating step and post treating step are same as that of the above embodiment. Also, the piston of the comparative sample 1 is same as that of the above embodiment and corresponds to the piston having been subjected to the treatment represented by “T5” in the refining mark (JIS H 0001) defined in JIS.
  • the conventional manufacturing method is used for manufacturing a piston of comparative sample 2. It differs from that of the embodiment in two points.
  • the first point is sphering of the eutectic Si phase is not performed, and the second point is the solution treatment is performed after the pressure die-casting. That is, a base metal same as that of the embodiment is melted, subjected to a molten metal treating step including only the degassing treatment and the dreg-removing treatment, to the solution treatment after the pressure die-casting step, and to the artificial-age treating step and the post treating step.
  • the casted article having been casted is heated up to 490° C., maintained in this state for 1 hour and quenched, as the solution treatment.
  • the piston of the comparative sample 2 is same as that of the above embodiment, and corresponds to the piston having been subjected to the treatment represented by “T6” in the refining mark (JIS H 0001) defined in JIS.
  • Wear-proof character of the pistons 6 is evaluated by measuring worn amount of each piston 6 at the semi-spherical seat surface 6 c engaging with the shoe 9 , after above operation of the swash-plate type compressor. Concretely, as shown in FIG. 4, dimension of gap L between the swash plate 8 and the shoe 9 before and after the operation is measured to calculate a varied amount ⁇ L. The varied amount ⁇ L is assumed as worn amount of the semi-spherical seat surface 6 c of the piston 6 .
  • FIG. 5 Measured results of worn amount of the pistons are shown in FIG. 5.
  • the worn amounts of the pistons 6 of the embodiment, comparative sample 1 and the comparative sample 2 are respectively 5 to 19 ⁇ m, 200 to 300 ⁇ m and 5 to 20 ⁇ m.
  • the worn amount of the former piston 6 is about one-twentieth of the latter piston.
  • the sphering treatment of eutectic Si phase greatly increasing the wear-proof character can be confirmed.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
  • Compressor (AREA)
US09/823,879 2000-03-30 2001-03-30 Piston for swash-plate type compressor and manufacturing method of the same Abandoned US20010037845A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2000093477A JP2001279358A (ja) 2000-03-30 2000-03-30 斜板式圧縮機用ピストンおよびその製造方法
JP2000-93477 2000-03-30

Publications (1)

Publication Number Publication Date
US20010037845A1 true US20010037845A1 (en) 2001-11-08

Family

ID=18608658

Family Applications (1)

Application Number Title Priority Date Filing Date
US09/823,879 Abandoned US20010037845A1 (en) 2000-03-30 2001-03-30 Piston for swash-plate type compressor and manufacturing method of the same

Country Status (3)

Country Link
US (1) US20010037845A1 (ja)
EP (1) EP1138945A2 (ja)
JP (1) JP2001279358A (ja)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1309956C (zh) * 2003-08-08 2007-04-11 上海三电贝洱汽车空调有限公司 用于斜盘式压缩机的斜盘
CN1309957C (zh) * 2003-08-08 2007-04-11 上海三电贝洱汽车空调有限公司 用于斜盘式压缩机的活塞
US20080006149A1 (en) * 2006-07-03 2008-01-10 Takayuki Kato Compressor

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4590784B2 (ja) * 2001-06-18 2010-12-01 アイシン精機株式会社 摺動部材および弁開閉時期制御装置
JP4584682B2 (ja) * 2004-11-12 2010-11-24 ヤマハ発動機株式会社 鋳造用アルミニウム合金の酸化物除去方法
JP2021050368A (ja) * 2019-09-20 2021-04-01 株式会社Ｍｒｄｃ アルミニウム合金の溶湯中のリン化アルミニウムクラスター除去方法

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1309956C (zh) * 2003-08-08 2007-04-11 上海三电贝洱汽车空调有限公司 用于斜盘式压缩机的斜盘
CN1309957C (zh) * 2003-08-08 2007-04-11 上海三电贝洱汽车空调有限公司 用于斜盘式压缩机的活塞
US20080006149A1 (en) * 2006-07-03 2008-01-10 Takayuki Kato Compressor

Also Published As

Publication number Publication date
JP2001279358A (ja) 2001-10-10
EP1138945A2 (en) 2001-10-04

Similar Documents

Publication Publication Date Title
US6921512B2 (en) Aluminum alloy for engine blocks
US6261390B1 (en) Process for nodulizing silicon in casting aluminum silicon alloys
EP0100470A2 (en) Heat-resistant, wear-resistant, and high-strength aluminum alloy powder and body shaped therefrom
EP1876251A2 (en) Compressor with aluminium alloy housing
US20010037845A1 (en) Piston for swash-plate type compressor and manufacturing method of the same
CN104805339A (zh) 一种汽车空调压缩机空心活塞及其生产方法
US9650700B2 (en) Swash plate and method of manufacturing the same
CN115852213A (zh) 一种免热处理压铸铝合金及其制备方法
JPH06293933A (ja) 耐摩耗性アルミニウム合金及びその製造方法
CN109022945B (zh) 一种制冷压缩机的上下轴承法兰、隔板及汽缸体专用稀土铝合金材料及其制备方法
KR100993584B1 (ko) Ｓｎ-Ｓｂ계 베어링 합금 및 그의 제조방법
Zainon et al. The effects of Mg2Si (p) on microstructure and mechanical properties of AA332 composite
JP2000192180A (ja) 疲労強度に優れたダイカスト製スクロール及びその製造方法
US6572816B1 (en) Free-machinable hyper-eutectic Al-Si alloy
KR20110084015A (ko) 자동차 공조기용 압축기의 실린더 블록용 소재 조성물
EP3165768B1 (en) Swash plate and method of manufacturing swash plate
WO2000043152A1 (en) Alloy for semi-solid casting process
CN118241086B (zh) 铝合金活塞及其制备方法
JPH03111531A (ja) アルミニウム合金製ローター
JP4045130B2 (ja) 快削性の共晶Ａｌ−Ｓｉ系合金
KR101309720B1 (ko) 바나듐이 첨가된 자동차 피스톤용 Ａｌ-Ｓｉ 합금 및 그 제조방법
CN113088770A (zh) 一种汽车空调压缩机的双向活塞及其制备方法

Legal Events

Date Code Title Description
AS Assignment

Owner name: KABUSHIKI KAISHA TOYODA JIDOSHOKKI SEISAKUSHO, JAP

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KATO, TAKAYUKI;TAKAMATSU, MASATO;KATAYAMA, SEIJI;REEL/FRAME:011677/0162

Effective date: 20010319

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION