EP1249604A1 - Piston pour compresseur à plateau en biais - Google Patents

Piston pour compresseur à plateau en biais Download PDF

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Publication number
EP1249604A1
EP1249604A1 EP20010109047 EP01109047A EP1249604A1 EP 1249604 A1 EP1249604 A1 EP 1249604A1 EP 20010109047 EP20010109047 EP 20010109047 EP 01109047 A EP01109047 A EP 01109047A EP 1249604 A1 EP1249604 A1 EP 1249604A1
Authority
EP
European Patent Office
Prior art keywords
piston
shoe
pressure
bearing
bearing shoe
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.)
Withdrawn
Application number
EP20010109047
Other languages
German (de)
English (en)
Inventor
Otfried c/o Zexel Valeo Compressor Schwarzkopf
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.)
Valeo Thermal Systems Japan Corp
Original Assignee
Zexel Valeo Climate Control Corp
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 Zexel Valeo Climate Control Corp filed Critical Zexel Valeo Climate Control Corp
Priority to EP20010109047 priority Critical patent/EP1249604A1/fr
Publication of EP1249604A1 publication Critical patent/EP1249604A1/fr
Withdrawn legal-status Critical Current

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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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2253/00—Other material characteristics; Treatment of material
    • F05C2253/12—Coating

Definitions

  • the present invention relates to a piston for use in a swash plate compressor, in particular a CO 2 compressor, for a vehicle air-conditioning system and to a compressor incorporating such a piston.
  • US 5,387,091 describes a variable capacity type swash plate compressor for an air-conditioning system in a vehicle having a drive shaft and at least one piston movable in a cylinder.
  • a swinging swash plate of the compressor is provided on each side with an annular rail over which is fitted a semi-spherical inner sliding shoe.
  • the inner sliding shoes engage semi-spherical outer shoes machined on inner surfaces of a swash plate receiving groove at the neck of a piston of the compressor. This arrangement allows a separation between the rotational movement that takes place between the swash plate and the inner sliding shoes, and the translational movement of the outer shoes and the piston.
  • the wobble plate arrangement comprises a swash plate on which a wobble plate is rotatably mounted and between the wobble plate and the piston is arranged a bearing which allows movements of the wobble plate relative to the piston in a circumferential direction.
  • the wobble plate is able to rotate freely both with respect to the swash plate and with respect to the piston.
  • the bearing comprises a slider shoe arrangement in which a pair of part-spherical sliding shoes are swivel mounted between two complementarily formed outer shoes located in a recess of the piston, the wobble plate being received between two opposed smooth sliding surfaces of the sliding shoes respectively.
  • the two outer shoes are provided by bearing shells which are fixed in the piston.
  • the object of the present invention is to provide a piston for use in a compressor as described above which overcomes or substantially mitigates the aforementioned disadvantages.
  • a piston for use in a compressor for a vehicle air conditioning system comprising a piston head at one end and defining a recess at its other end, and comprising a pressure-bearing shoe which is connected to the piston on the piston head-side of the recess, characterised in that the pressure-bearing shoe is connected to the piston in a fixed, non-rotational manner.
  • the pressure-bearing shoe is fitted axially to an end of the piston adjacent the recess.
  • the pressure-bearing shoe is connected to the piston by means of mating formations formed respectively on or in the shoe and on or in the piston.
  • the mating formations are arranged around the circumference of the piston in such a way that lateral forces acting on the piston cannot push the shoe out of position with respect to the piston.
  • the mating formations are formed by machining of the piston from one end in a direction parallel with the longitudinal axis of the piston.
  • the mating formations comprise one or a series of projections formed on the shoe which locate into respectively into complementarily shaped rebates defined by the piston or vice versa .
  • the projections and the rebates have a rectangular section.
  • the rectangular section rebates define three adjoining sides which take up any lateral forces acting on the pressure-bearing shoe.
  • the pressure-bearing shoe is preferably connected to the piston by means of pins.
  • the pressure-bearing shoe is connected to the piston by being clamped or adhered thereto.
  • the pressure-bearing shoe is also connected to the piston by means of mating formations which are formed by a deformation of the shoe circumferentially around the piston thereby clamping the shoe to the piston.
  • the pressure-bearing shoe is made primarily of steel whereas the piston is made primarily of aluminum.
  • the pressure-bearing shoe is integrally formed with the piston.
  • the pressure-bearing shoe is preferably formed from a coating applied to the piston.
  • the pressure-bearing shoe is formed by a ceramic coating which has been applied by thermal spraying to the piston and which has been subsequently machined to define the shoe.
  • the pressure-bearing shoe defines a part-spherical pressure-bearing surface through which in use translational forces may be transmitted to the shoe from a slider shoe in contact therewith.
  • the part-spherical pressure-bearing surface is formed by machining of the pressure-bearing shoe.
  • the pressure-bearing shoe preferably transmits the translational forces to the bottom of the piston via a contact surface at the bottom of the piston, the part-spherical pressure-bearing surface having a surface area which is substantially smaller than the surface area of the contact surface.
  • the piston comprises a cylindrical body with the piston head at one end and a foot portion at its other end, and a bridge links the foot portion to the cylindrical body, the recess being defined between the foot portion and the cylindrical body.
  • the foot portion is provided with a part-spherical bearing surface so that in use translational forces may be transmitted directly to the surface from a slider shoe in contact therewith.
  • the width of the foot portion is substantially smaller than the diameter of the cylindrical body.
  • a compressor for a vehicle air conditioning system comprising a piston according to the first aspect of the invention.
  • a compressor for a vehicle air conditioning system comprising at least one piston moveable in a cylinder, a drive shaft, a wobble plate arrangement comprising a swash plate on which a wobble plate is rotatable mounted located between the piston and the drive shaft, a bearing mounted in the piston into which the wobble plate extends, and a pressure-bearing shoe on the piston-side of the wobble plate, characterised in that the pressure-bearing shoe is connected to the piston in a fixed, non-rotational manner.
  • the piston comprising the pressure-bearing shoe is such at it can be manufactured and assembled relatively simply and provides a safeguard against any relative rotation between the pressure-bearing shoe and the piston.
  • the connection between the pressure-bearing shoe and the piston is such that the pressure-bearing shoe can transmit the surface pressure of adjacent sliding shoes to the piston without any unacceptably high surface pressure causing damage to the piston, especially if the piston is made of aluminum.
  • the need for a separate pressure-bearing shoe to be connected to the piston on the regulating-side of the recess of the piston can also be eliminated, which enables the overall piston length and therefore that of the driving mechanism of the compressor to be considerably reduced.
  • the piston 1 shown in Figs. 1 and 2 comprises a cylindrical body 2 with a head portion 3 at one end and a foot portion 4 at its other end.
  • a bridge 5 links the foot portion 4 to the cylindrical body 2 so that a recess 6 is defined between the foot portion 4 and the cylindrical body 2.
  • the recess 6 is intended to accommodate a bearing 7 for a wobble plate arrangement of the compressor as shown in Fig. 3.
  • a pressure-bearing shoe 8 is mounted at the bottom of the cylindrical body 2 on the piston-head side of the recess 6.
  • the shoe 8 is mounted axially on to the bottom of the cylindrical body 2 and connects thereto by means of mating formations 9a, 9b formed respectively on and in the shoe 8 and the bottom of the cylindrical body 2.
  • the mating formations comprise one or a series of projections 9a formed on the shoe 8 which locate respectively into complementarily shaped rebates 9b defined in the bottom of the body 2, or vice versa. This arrangement prevents any relative rotation between the shoe 8 and the piston body 2.
  • the mating formations 9a, 9b centre the shoe 8 on the body 2.
  • the projections 9a and the rebates 9b have a rectangular section but they may have different profiles provided that they mate with one another. It is however important that they are arranged around the circumference of the piston 1 in such a way that the shoe 8 interlocks with the body 2 and lateral forces acting on the piston 1 cannot push the shoe 8 out of its interlocked position with the cylindrical body 2.
  • rectangular section rebates 9b enable any lateral forces acting on the shoe 8 to be taken up by the three adjoining sides 10a, 10b and 10c of the rebates 9b.
  • rectangular section projections 9a and rebates 9b enable the rebates 9b to be machined from the underside of the foot portion 4 of the piston 1 and preferably the foot portion 4 is configured so as to permit machining of the rebates 9b in a direction parallel with the longitudinal axis 11 of the piston 1.
  • the shoe is pressure-bearing, it is preferably made from a material which is harder than that of the piston and, as is described below, it is possible for there to be a significant difference in the hardness of the materials used for each.
  • the shoe 8 is made from steel whereas the piston 2 is made of aluminum.
  • the shoe 8 comprises a part-spherical bearing surface 12 through which translational forces are transmitted to the shoe 8 from slider shoes 13 in contact therewith as shown in Fig. 3.
  • the pressure-bearing shoe 8 then transmits these forces to the bottom of the piston 1 via a contact surface 14 at the bottom of the cylindrical body 2 of the piston 1.
  • the surface area of the bearing surface 12 can be made significantly smaller than the area of the contact surface 14, which can be made large enough to enable the piston 1 to be made from aluminum or an aluminum material.
  • the surface area of the bearing surface 12 can be made between two and three times smaller than the surface area of the contact surface 14.
  • the wobble plate performs only small rotational movements so that the product of the surface pressure and the velocity is small and the slider shoes 8 can be made with small dimensions, mainly taking into account only the surface pressure.
  • the size of the sliding shoes 13 therefore determines the size of the complementarily formed bearing surfaces 12 of the shoes 8.
  • the diameters of the part-spherical surfaces 12 and the part spherical surfaces of the slider shoes 13 are in the range 8 mm to 12 mm inclusive.
  • the shoe 8 may be made by appropriately machining a component, in which case it may not need any hardening, especially in the region of the bearing surface 12, as the machining process itself will strength the surface of the shoe.
  • the shoe may be made by stamping or punching from a blank.
  • the foot portion 4 of the piston 1 must also be dimensioned so that it is capable of withstanding the forces which it must carry without deformation or cracking. In this regard, it is preferable to increase the thickness of the foot portion 4 rather than its width relative to its longitudinal length because the geometrical moment of inertia is essentially determined by the height of the foot portion 4.
  • the width of the foot portion 4 is therefore preferably substantially smaller than the diameter of the cylindrical body 2, which also facilitates the machining of the rebates 9b in a direction parallel with the longitudinal axis 11 of the piston 1.
  • the foot portion 4 is provided with a part-spherical bearing surface 15 so that translation forces are transmitted directly to it, without any interposed pressure-bearing shoe equivalent to the shoe 8.
  • a part-spherical bearing surface 15 so that translation forces are transmitted directly to it, without any interposed pressure-bearing shoe equivalent to the shoe 8.
  • the piston 1 as described above has thus been designed to withstand the translation forces transmitted to it in a differentiated way.
  • Fig. 3 shows a driving mechanism, without any casing, of a compressor incorporating a piston as described above.
  • the same parts of the piston as have already been described have been given the same reference numerals in the following description.
  • the compressor comprises a CO 2 compressor for a vehicle air-conditioning system wherein the ratio of the piston diameter, that is the diameter of the cylindrical body 2, to piston stroke is preferably approximately 1.
  • the compressor comprises a drive shaft 16 and at least one piston 1 movable in a cylinder (not shown).
  • a wobble plate arrangement 17 comprising a swash plate 18 on which a wobble plate 19 is rotatably mounted is arranged between the piston 1 and the drive shaft 15.
  • the wobble plate 19 is able to rotate freely both with respect to the swash plate 18 and with respect to the piston 1.
  • the wobble plate 19 extends into the bearing 7 which is located in the recess 6 of the piston 1 and which allows movements of the wobble plate 19 relative to the piston 1 in a circumferential direction.
  • the bearing comprises a slider shoe arrangement in which a pair of part-spherical sliding shoes 13 (as mentioned above) are swivel mounted between the pressure-bearing shoe 8 connected to the bottom of the cylindrical body 2 of the piston on the piston-head side of the recess 6 and the part-spherical bearing surface 14 provided on the foot portion 4 of the piston 1.
  • the pressure-bearing shoe 8 is not connected to the piston 1 by the use of mating formations 9a, 9b formed respectively on and in the shoe 8 and bottom of the cylindrical body 2 but is pinned to the cylindrical body 2 of the piston.
  • the mating formations 9a, 9b are therefore not required.
  • Two pins, for example, would be sufficient to safeguard the shoe 8 against rotation relative to the piston 1.
  • bores for the pins are provided in such a position in the cylindrical body 2 of the piston 1 that they can be made by machining laterally past the piston foot in a direction parallel with the longitudinal axis 11 of the piston 1.
  • the pressure-bearing shoe 8 is attached to the cylindrical body 2 of the piston 1 by being clamped or adhered thereto.
  • the shoe 8 itself may also be formed by pressing or stamping.
  • Fig. 4 is shown an embodiment wherein the pressure-bearing shoe 8 is clamped to the cylindrical body of the piston 1 by deformation.
  • the shoe 8 is mounted axially at the bottom of the cylindrical body 2 on the piston-head side of the recess 6 and comprises a cup which is located over the end of the cylindrical body 2.
  • the shoe 8 is connected to the body 2 by means of mating formations 20 formed by pressing an annular groove 21 into the exterior of the shoe 8 circumferentially around the cylindrical body 2, which groove 21 deforms the underlying body 2 of the piston 1 to form the two mating formations 20 thus clamping the shoe 8 to the body 2.
  • the piston 1 is calibrated to ensure that the shoe 8, once clamped in position, will be located correctly. This calibration is accomplished using a calibration tool which is inserted into the recess 6 and then turned to ensure that the part-spherical bearing surfaces 12 and 15 are correctly aligned.
  • a calibrating tool 22 has a profile which defines two part-spherical surfaces 23 and 24 of diameter d. These surfaces 23 and 24 are arranged so that they exactly match the diameter, alignment and separation of the two part-spherical bearing surfaces 12 and 15, which also have a diameter d. However, the tool 22 has a reduced width b which corresponds to the width of the recess 6 (see Fig. 6) so that it can be inserted into the recess 6. Upon insertion, the surfaces 23 and 24 are out of alignment with the surfaces 12 and 14 but when the tool 22 is turned axially through 90°, the surfaces 23 and 24 lie adjacent the surfaces 12 and 15 respectively. This enables the position of the shoe 8 and thereby the surface 12 which it defines to be correctly adjusted prior to the attachment of the shoe 8 to the cylindrical body 2.
  • the shoe 8 is connected to the cylindrical body 2 of the piston 1 by caulking.
  • the shoe 8 also comprises a cup which is located over the end of the cylindrical body 2.
  • a calibrating tool 22 as previously described and with dimensions b and d is used to ensure the correct position of the shoe 8 relative to the body 2 of the piston 1. The shoe 8 is then fixed in this position by caulking or other adhesive means.
  • the shoe is mounted on the body 2 of the piston after separate final machining of the part-spherical surfaces 12 and 15.
  • the shoe 8 it is possible to attach the shoe 8 to the body 2 of the piston by the means previously described before final machining of the surfaces 12 and 15 has taken place, although this is considerably more difficult to accomplish.
  • the machine tools used would also have to have dimensions b and d in order that they can be inserted into the recess 6 to machine the surfaces 12 and 15. In any event, for quiet operation of the mechanism, the surfaces 12 and 15 must be machined with a high precision.
  • the pressure-bearing shoe 8 is provided by a coating applied to the piston 1.
  • a coating process must be chosen which provides a thickly coated layer on the exterior of the cylindrical body 2 of the piston 1 in order to enable the part-spherical bearing surface 12 through which translational forces are transmitted to the shoe 8 to be machined from the coated layer.
  • the coating should have a thickness at least in the order of millimetres of thickness.
  • a ceramic coating applied by thermal spraying fulfils these requirements.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
EP20010109047 2001-04-11 2001-04-11 Piston pour compresseur à plateau en biais Withdrawn EP1249604A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP20010109047 EP1249604A1 (fr) 2001-04-11 2001-04-11 Piston pour compresseur à plateau en biais

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP20010109047 EP1249604A1 (fr) 2001-04-11 2001-04-11 Piston pour compresseur à plateau en biais

Publications (1)

Publication Number Publication Date
EP1249604A1 true EP1249604A1 (fr) 2002-10-16

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP20010109047 Withdrawn EP1249604A1 (fr) 2001-04-11 2001-04-11 Piston pour compresseur à plateau en biais

Country Status (1)

Country Link
EP (1) EP1249604A1 (fr)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1837724A (en) * 1929-12-20 1931-12-22 Michell Crankless Engines Corp Crankless mechanism and method of making crankless mechanisms
US5201261A (en) * 1990-11-29 1993-04-13 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Piston coupling mechanism for a swash plate compressor
JPH05149246A (ja) * 1991-11-29 1993-06-15 Sanden Corp 圧縮機のピストン構造
US5387091A (en) 1992-08-21 1995-02-07 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Variable capacity type swash plate compressor
JPH10205440A (ja) * 1997-01-23 1998-08-04 Sanden Corp 中空ピストン及びそれを用いた斜板式圧縮機
US5826490A (en) 1996-05-24 1998-10-27 Danfoss A/S Compressor, in particular for air-conditioning systems in vehicles
EP0992682A2 (fr) * 1998-10-05 2000-04-12 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Compresseur à piston
EP1035326A2 (fr) * 1999-03-08 2000-09-13 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Revêtement de compresseur
EP1074737A2 (fr) * 1999-08-06 2001-02-07 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Surface de lubrification sur le siège de piston d'un compresseur de réfrigérant à plateau en biais

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1837724A (en) * 1929-12-20 1931-12-22 Michell Crankless Engines Corp Crankless mechanism and method of making crankless mechanisms
US5201261A (en) * 1990-11-29 1993-04-13 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Piston coupling mechanism for a swash plate compressor
JPH05149246A (ja) * 1991-11-29 1993-06-15 Sanden Corp 圧縮機のピストン構造
US5387091A (en) 1992-08-21 1995-02-07 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Variable capacity type swash plate compressor
US5826490A (en) 1996-05-24 1998-10-27 Danfoss A/S Compressor, in particular for air-conditioning systems in vehicles
JPH10205440A (ja) * 1997-01-23 1998-08-04 Sanden Corp 中空ピストン及びそれを用いた斜板式圧縮機
EP0992682A2 (fr) * 1998-10-05 2000-04-12 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Compresseur à piston
EP1035326A2 (fr) * 1999-03-08 2000-09-13 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Revêtement de compresseur
EP1074737A2 (fr) * 1999-08-06 2001-02-07 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Surface de lubrification sur le siège de piston d'un compresseur de réfrigérant à plateau en biais

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 017, no. 544 (M - 1489) 30 September 1993 (1993-09-30) *
PATENT ABSTRACTS OF JAPAN vol. 1998, no. 13 30 November 1998 (1998-11-30) *

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