WO1994024436A1 - Cylindre pour compresseur hermetique a mouvement alternatif - Google Patents

Cylindre pour compresseur hermetique a mouvement alternatif Download PDF

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Publication number
WO1994024436A1
WO1994024436A1 PCT/BR1994/000015 BR9400015W WO9424436A1 WO 1994024436 A1 WO1994024436 A1 WO 1994024436A1 BR 9400015 W BR9400015 W BR 9400015W WO 9424436 A1 WO9424436 A1 WO 9424436A1
Authority
WO
WIPO (PCT)
Prior art keywords
cylinder
piston
dead point
radial distance
reciprocating piston
Prior art date
Application number
PCT/BR1994/000015
Other languages
English (en)
Inventor
Dietmar Erich Bernhard Lilie
Ernani Pautasso Nunes Junior
Original Assignee
Empresa Brasileira De Compressores S/A. - Embraco
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 Empresa Brasileira De Compressores S/A. - Embraco filed Critical Empresa Brasileira De Compressores S/A. - Embraco
Priority to EP94913458A priority Critical patent/EP0647292A1/fr
Priority to JP6522564A priority patent/JPH07508333A/ja
Publication of WO1994024436A1 publication Critical patent/WO1994024436A1/fr

Links

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
    • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
    • F04B39/12—Casings; Cylinders; Cylinder heads; Fluid connections
    • F04B39/122—Cylinder block

Definitions

  • the present invention refers to a cylinder for a reciprocating hermetic compressor of the type used in small refrigerating systems.
  • the reciprocating motion of a piston inside a cylindrical cavity such as a cylinder provided in the cylinder block of said hermetic compressors, define suction and compression strokes of refrigerant gas during each operative cycle of the piston.
  • the refrigerant gas is aspirated from a suction chamber towards the cylinder inside, through a suction orifice provided on a valve plate, during the suction stroke and it is discharged during the compression stroke from the inside of the cylinder to a discharge chamber, through a discharge orifice provided on said valve plate.
  • the suction and compression strokes of the operative cycle of the reciprocating piston are defined by the stroke end positions of said piston, respectively known as upper dead point position and lower dead point position.
  • the cylinder within which reciprocates the piston, presents a constant cylindricity throughout its length, said cylindricity defining, in a transversal profile, walls that are parallel to the respective walls of a reciprocating piston mounted inside said cylinder.
  • the radial distance between the cylinder wall and the piston wall is calculated in order to be sufficient to receive, by superficial adherence, a lubricant oil film that reduces the friction between the walls of the cylinder and reciprocating piston, mainly when said piston comes closer to the upper dead point, where the pressure rises quickly with the advance of the reciprocating piston.
  • a cylinder for a reciprocating hermetic compressor of the type comprising: a cylinder block presenting an internal cylindrical cavity, in which inside reciprocates a piston between a lower dead point and an upper dead point, said reciprocating piston presenting an upper end face, the radial distance between the lateral wall of the reciprocating piston and the adjacent lateral wall of the cylinder, according to a plane containing the upper end face of the reciprocating piston, varying at least along the cylinder length, in order that, at the region of the cylinder adjacent to the portion where there is reached the upper dead point condition, said radial distance is minimum.
  • Fig. 1 illustrates, in a longitudinal section view, a reciprocating piston disposed inside a cylinder, which is closed by a valve plate and cylinder head, according to the state of the art
  • Fig. 2 illustrates an enlarged view of the assembly of figure 1, without the connecting rod of the piston, the latter being at its upper dead point;
  • Figures 3a and 3b illustrate, in an enlarged longitudinal section view, similar views to that of figure 2, but presenting a cylindrical cavity, which is shaped according to two different embodiments of the present invention.
  • Reciprocating hermetic compressors comprise a cylinder block 1, which is lodged inside a hermetic shell (not illustrated) and which presents a cylindrical cavity such as a cylinder 2, in which inside reciprocates a piston 3.
  • the cylinder block 1 presents a pair of opposite faces, to which are opened the ends of the cylinder 2.
  • a valve plate 5 and a cylinder head 6, which forms together with said valve plate 5 two internal cavities, defining a suction chamber 8 and a discharge chamber 9.
  • the cylinder 2 maintains a selective fluid communication with said suction chamber 8 and discharge chamber 9, through respective gas suction orifice 5a and gas discharge orifice 5b, provided on the valve plate 5, eccentrically to the geometric axis of the cylinder 2, and onto which are mounted respective suction valve 10 and discharge valve 11, which operate synchronously during the suction and discharge strokes of the operative cycle of the piston 3.
  • the reciprocating piston 3 presents a free end face 3a, facing the valve plate 5, and an opposite end 3b, by which said reciprocating piston 3 is driven through a connecting rod 20.
  • the reciprocating piston 3 presents a continuous linear movement, having a suction stroke and a discharge stroke, which begin, respectively, at the upper dead point and at the lower dead point.
  • the cylinder 2 presents a cylindricity that remains constant throughout its length, from the edge thereof adjacent to the upper dead point region of the reciprocating piston 3 and close to the valve plate 5, up to another opposite edge, which is adjacent to the lower dead point region of said piston 3, defining, in a transversal profile, a parallelism between the adjacent walls of the cylinder 2 and piston 3.
  • the diameter of said cylinder 2 is defined so that its lateral wall and the lateral wall of the piston 3 keep a constant minimum mutual radial distance, which is necessary to allow a fine oil film to be retained between the surfaces of the lateral walls of the cylinder and piston, in order to minimize the friction between said cylinder and piston during the motion of said piston inside the cylinder 2.
  • This lubrication is mainly required during the final phase of the compression stroke, when the pressure inside the cylinder 2 increases rapidly. Nevertheless, when the piston is close to the upper dead point, this oil film is not enough to avoid the friction wear between the reciprocating piston 3 and the cylinder 2. In order to minimize this wear, it would be necessary to increase the distance between the cylinder 2 and the piston 3. Though the increase of said distance does not alter the results of gas suction during the corresponding cycle of the piston, said distance, during compression, implies an increase of gas leakage to the low pressure region of the refrigerating system. Said gas leakage is even more significant as the reciprocating piston approaches the upper dead point, thereby resulting in efficiency loss for the compressor.
  • the cylinder 2 presents, between its opposite ends, a diametral variation calculated in order to optimize the gas pumping inside the cylinder, by action of the reciprocating piston 3, said optimized operation resulting in the minimization of the friction losses between said cylinder and piston, as well as losses due to leakage of the gas being compressed at the low pressure region of the refrigerating system.
  • This diametral variation is obtained according to at least a plane containing the free end face 3a of the reciprocating piston 3.
  • the cylinder is defined as a conical cavity, whose walls maintain a constant conicality throughout the length of the cylinder, between the upper dead point and lower dead point regions.
  • the ideal optimum point is located approximately at the central region of the cylinder 2.
  • the ideal optimum point defines a region of the cylinder length, where the piston-cylinder radial distance is such that, during compression, the losses due to friction and to compressed gas leakage are optimum. Above this region, the cylinder 2 presents a radial distance from the reciprocating piston 3 that is smaller than the distance at said ideal optimum point, while, below said region, this distance is larger than said distance at the ideal optimum point.
  • the minimum radial distance between the cylinder 2 and reciprocating piston 3 occurs only at the upper dead point region, between the peripheral edge of the free end face of the piston 3 and the wall of the cylinder 2, thereby allowing a certain escape of lubricant oil between the piston and cylinder walls, due to the pressure existing at this region, consequently increasing the gas leakage.
  • the region of the cylinder immediately adjacent to the portion thereof where the upper dead point is defined should present a constant radial distance, i.e., a constant cylindrical distance. At this cylindrical portion of reduced radial clearance, the oil forms a barrier against gas flow, thereby avoiding gas leakage even in high pressure conditions.
  • the variation of the cylinder- piston radial distance is obtained by varying the profile of said cylinder 2 throughout the length thereof.
  • the diameter of the cylinder is calculated, for each position of the piston stroke, in function of some operative parameters of said piston, such as pressure in each said position and motion velocity between each two consecutive positions, i.e., the time that said piston stays in each of said positions.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressor (AREA)

Abstract

Cylindre pour compresseur hermétique à mouvement alternatif, du type comportant un bloc-cylindre présentant une cavité cylindrique interne (2) à l'intérieur de laquelle un piston (3) est monté alternatif entre un point mort inférieur et un point mort supérieur, ledit piston alternatif (3) présentant une face terminale supérieure (3a), et la distance radiale comprise entre la paroi latérale du piston alternatif (3) et la paroi latérale adjacente du cylindre (2) variant sur toute la longueur du cylindre, de sorte que ladite distance radiale est la plus faible dans la zone du cylindre (2) qui est voisine de la partie de celui-ci où l'état de point mort supérieur est atteint.
PCT/BR1994/000015 1993-04-22 1994-04-22 Cylindre pour compresseur hermetique a mouvement alternatif WO1994024436A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP94913458A EP0647292A1 (fr) 1993-04-22 1994-04-22 Cylindre pour compresseur hermetique a mouvement alternatif
JP6522564A JPH07508333A (ja) 1993-04-22 1994-04-22 往復気密圧縮機用シリンダ

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BRPI9300994 1993-04-22
BR9300994A BR9300994A (pt) 1993-04-22 1993-04-22 Cilindro para compressor hermético alternativo

Publications (1)

Publication Number Publication Date
WO1994024436A1 true WO1994024436A1 (fr) 1994-10-27

Family

ID=4056070

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/BR1994/000015 WO1994024436A1 (fr) 1993-04-22 1994-04-22 Cylindre pour compresseur hermetique a mouvement alternatif

Country Status (4)

Country Link
EP (1) EP0647292A1 (fr)
JP (1) JPH07508333A (fr)
BR (1) BR9300994A (fr)
WO (1) WO1994024436A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009503368A (ja) * 2005-07-22 2009-01-29 ワールプール，ソシエダッド アノニマ 可変の直径方向のクリアランスを有するピストン・シリンダアセンブリと、可変の直径方向のクリアランスを有するピストン・シリンダアセンブリに使用されるシリンダ
US20090148322A1 (en) * 2007-11-30 2009-06-11 Hitachi, Ltd. Cylinder apparatus, compressor and manufacturing method of cylinder apparatus
US8794933B2 (en) 2008-05-12 2014-08-05 Panasonic Corporation Hermetic compressor
EP2256344A4 (fr) * 2008-10-29 2018-03-07 Panasonic Corporation Compresseur étanche

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5810273B2 (ja) * 2010-10-21 2015-11-11 パナソニックＩｐマネジメント株式会社 密閉型圧縮機および冷凍装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5477315A (en) * 1977-12-02 1979-06-20 Hitachi Ltd Cylinder of reciprocating compressor
DD236148A1 (de) * 1985-04-12 1986-05-28 Dkk Scharfenstein Veb Kurbeltrieb fuer hermetische kaeltemittelverdichter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5477315A (en) * 1977-12-02 1979-06-20 Hitachi Ltd Cylinder of reciprocating compressor
DD236148A1 (de) * 1985-04-12 1986-05-28 Dkk Scharfenstein Veb Kurbeltrieb fuer hermetische kaeltemittelverdichter

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 3, no. 101 (M - 070) 25 August 1979 (1979-08-25) *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009503368A (ja) * 2005-07-22 2009-01-29 ワールプール，ソシエダッド アノニマ 可変の直径方向のクリアランスを有するピストン・シリンダアセンブリと、可変の直径方向のクリアランスを有するピストン・シリンダアセンブリに使用されるシリンダ
CN101228354B (zh) * 2005-07-22 2013-09-18 惠而浦股份公司 具有可变径向间隙的活塞-汽缸组件及其汽缸
US20090148322A1 (en) * 2007-11-30 2009-06-11 Hitachi, Ltd. Cylinder apparatus, compressor and manufacturing method of cylinder apparatus
US8206137B2 (en) * 2007-11-30 2012-06-26 Hitachi, Ltd. Cylinder apparatus, compressor and manufacturing method of cylinder apparatus
US8794933B2 (en) 2008-05-12 2014-08-05 Panasonic Corporation Hermetic compressor
US8814539B2 (en) 2008-05-12 2014-08-26 Panasonic Corporation Hermetic compressor
US9745973B2 (en) 2008-05-12 2017-08-29 Panasonic Corporation Hermetic compressor
EP2256344A4 (fr) * 2008-10-29 2018-03-07 Panasonic Corporation Compresseur étanche

Also Published As

Publication number Publication date
EP0647292A1 (fr) 1995-04-12
BR9300994A (pt) 1994-11-22
JPH07508333A (ja) 1995-09-14

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