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
  • F04B39/0005—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 adaptations of pistons
• • 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
  • F04B35/00—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
  • F04B35/04—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for the means being electric
  • F04B35/045—Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for the means being electric using solenoids
• • 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
  • F04B39/02—Lubrication
  • F04B39/0284—Constructional details, e.g. reservoirs in the casing
  • F04B39/0292—Lubrication of pistons or cylinders
• • 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
  • F04B39/123—Fluid connections
• • 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
  • F05C2203/00—Non-metallic inorganic materials
  • F05C2203/08—Ceramics; Oxides
  • F05C2203/0804—Non-oxide ceramics
  • F05C2203/0813—Carbides
• • 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 compressor with a cylinder in which a piston is movably held by a gas pressure bearing without contact with the cylinder wall.
• Such a compressor is known, for example, from US Pat. No. 6,575,716 A1.
• a circumferential groove is formed in the inner wall of the cylinder, which is supplied via a cylinder wall crossing bore with compressed gas.
• the compressed gas is distributed in the circumferential groove around the entire circumference of the piston and extends from the groove in the axial direction through a narrow gap between the piston and the cylinder wall, whereby it keeps the piston on its entire circumference without contact with the cylinder wall.
• a radial force acts on the piston and deflects it from its equilibrium position
• the compressed gas is not only compressed on one side of the piston circumference, but also partially displaced, wherein the displacement u. a. may be due to an escape of the gas back into the groove.
• the compressed gas on the piston causes a restoring force in the direction of the equilibrium position, the displaced gas can not do so. Due to the possibility of avoiding the stiffness of the bearing against radial deflection is not too large.
• the supply bores In order to effectively limit the backflow of the compressed gas, the supply bores must have a very small diameter of a similar order of magnitude as the gap width between cylinder wall and piston. In practice, this means that the diameter of the supply holes should not be more than a few 10 microns. Creating such close holes requires elaborate machining techniques such as laser ablation, spark erosion, or the like. With these techniques you can The supply holes are only produced individually, which makes the production tedious and expensive. In addition, the material thickness in which such narrow holes can be produced, limited to a few hundred microns. A workpiece with such a small wall thickness is easily deformable, so that it is difficult to ensure the dimensional accuracy and stability of the cylinder wall required for an effective gas pressure bearing.
• the aim of the present invention is to provide a compressor with a gas-pressure bearing piston, which can be realized with little effort and allows storage of the piston with good radial stiffness at low pressure gas flow.
• the object is achieved by a compressor with a cylinder and an oscillatingly movable piston in the cylinder and play transversely to the direction of movement, wherein an end face of the piston in the cylinder delimits a compression chamber, which is characterized in that the piston decreasing towards the end face Diameter. Due to the shape of the piston tapering towards the end face, part of the gas compressed in the compression chamber by the piston movement is introduced into the gap between piston and cylinder wall, and the gas escaping from the compression chamber between piston and cylinder wall is the gas pressure bearing effect unfolded.
• this preferably has adjacent to the compression chamber adjacent, the decreasing to the end face diameter portion having a guide portion with a constant diameter.
• the increase in the diameter is expediently continuous.
• the rate of change of the diameter in the direction of the axis immediately at the end face is maximum and decreases with increasing distance from the end face.
• the inner wall of the cylinder can be completely free of supply bores for the supply of pressurized gas into the gap between inner wall and piston.
• the gas flow through the gap stops at least once during each oscillation of the piston, so that at this time a contact between the piston and the cylinder wall can come about.
• the piston and / or the inner wall of the cylinder may be provided with a hard coating.
• the coating may consist of a carbide, for example tungsten carbide, DLC (diamond-like carbon) or the like.
• supply holes for the supply of compressed gas may be disposed in an inner wall of the cylinder so as to urge a portion of the piston facing the compression chamber at the inflection point of the piston movement at which the expansion the compression chamber is maximum.
• the compressor expediently has a drive unit which carries out a purely linear movement.
• a drive unit may in particular comprise a magnetic armature coupled to the piston, which is drivable in an alternating magnetic field parallel to the direction of movement of the piston.
• FIG. 1 shows a schematic section through the piston and cylinder of a compressor according to a first embodiment of the invention.
• FIG. 2 shows a schematic section through the drive unit of the compressor.
• FIG. 3 shows a section analogous to FIG. 1 according to a second embodiment of the invention;
• Fig. 5 is a frontal view of a sleeve used in the third embodiment.
• the compressor shown in FIG. 1 comprises a cylinder 21, which is essentially assembled from a tube piece 22, a head plate 23 covering one end of the tube piece 22 and a cap 24 fastened to a side of the head plate 23 facing away from the tube piece 22.
• Pipe section 22, head plate 23 and a piston 25 engaging in the pipe section 22 delimit a compression chamber 26.
• the compression chamber 26 communicates via valves 27, 28, shown schematically in the figure, preferably one-piece from the head plate 23 consisting of spring steel, with two in the cap 24
• the valves 27, 28 are check valves, the gas flow in each case only from the upper, suction-side chamber 29 in the compression chamber 26 at an outward movement of the piston 25 and from the compression chamber 26 in the lower, pressure-side chamber 30 at allow an inward movement of the piston 25.
• the piston has a the head plate 23 facing, flat end face 31, whose diameter is significantly smaller than that of the compression chamber 26. At its edges, the end face 31 is continuously curved in one of the inside of the pipe section 22 facing lateral surface 32 on.
• the lateral surface 32 can be divided into three sections in the direction of movement of the piston 25, a cylindrical central portion 33 whose diameter is at most a few 10 microns smaller than that of the compression chamber 26, so that its movement in the pipe section 22 is guided without play and essentially schlingerok , and, adjacent to the central portion 33, respectively, an inner and an outer portion 34 and 35, whose diameter decreases continuously with increasing distance from the central portion 33.
• the width of the gap 36 between the lateral surface 32 and the inner surface of the pipe section 22 grows faster with increasing distance from the central portion 33 than linear.
• the funnel-like widening gap 36 in this way to the compression chamber 26 promotes the penetration of compressed gas from the compression chamber 26, so that in the amount of the central portion 33 of the gas flow through the narrow gap 36 at this point is significantly stronger than a piston of exactly cylindrical shape ,
• a bearing effect corresponding to that of a conventional gas pressure bearing with gas supply into the gap can be realized via supply bores.
• the gas pressure bearing effect is only briefly interrupted when there is no pressure difference between the compression chamber 26 and the back of the piston 25.
• the entire cylinder 21 is encapsulated in a hermetic housing and the back of the piston 25 communicates with the suction-side chamber 29, this may be the case on the turning away from the head plate 23 inflection point of the piston.
• Compression chamber 26 drops below the pressure on the piston rear - such
• flow obstruction can be the valve 27 itself - the gas flow in the
• To these in the Compression chamber 26 directed gas flow to reinforce so that it unfolds a bearing effect decreases continuously in the outer portion 35 of the diameter of the piston from the central portion 33 to a rear end face 37 back.
• Fig. 2 shows schematically a drive unit, which is used for driving the oscillating movement of the piston 25 via a piston rod 38.
• the drive unit comprises two E-shaped yokes 1 with three mutually opposite arms 3, 4, 5.
• the mutually facing ends of the arms 3, 4, 5 each form an air gap 2 defining pole pieces 7.
• Around the middle arms 4 around is one Excitation winding 8 attached.
• the two exciter windings 8 can be acted upon by a control circuit with current, wherein the current direction in the two exciter windings 8 is in each case set so that the opposite pole pieces 7 of the middle arms 4 form unlike magnetic poles.
• the pole shoes of the outer arms 3 and 5 each form the adjacent middle arm 4 unlike magnetic poles.
• an armature 10 is suspended on two springs 11 between an upper and a lower (or a right and left reversal point in the illustration of FIG. 2) reversing point reversibly movable.
• the position of the armature 10 at the upper reversal point is shown by solid lines, dashed lines at the lower reversal point.
• the springs 11 are each punched out of a piece of sheet metal leaf springs with several zigzag extending arms 12.
• the arms 12 of a spring 11 each extend mirror images of each other from a central point on the anchor 10 to suspension points 13 on a rigid frame, not shown, on which also Yokes 1 and the compressor are anchored.
• the substantially rod-shaped armature 10 comprises in its central region a four-pole permanent magnet 14. While in a relaxed position of the springs 11 in which the arms 12 of each spring 1 1 lie substantially in a same plane, the magnet 14 centrally in the air gap. 2 is placed and a boundary line 15 extends between its in Fig. 1 left and right poles centered by the middle arms 4, is deflected by applying the windings 8 with a current of the armature 10 depending on the current direction to the left or to the right.
• Fig. 3 shows a modified embodiment of the compressor according to the invention, which can also be combined with the drive unit shown in Fig. 2.
• the compressor has a head plate 23 with valves 27, 28 and a cap 24 with chambers 29, 30 as described above with reference to FIG.
• the piston 25 has a construction with a cylindrical central portion 33 and tapered towards the end faces 31 and 37, respectively, inner and outer portions 34, 35.
• a sleeve 39 is accommodated, which together with the piston 25 and the head plate 23 limits the compression chamber 26.
• annular cavity 40 is sealed at its end facing away from the head plate 23 by an O-ring 41 or the like and an obliquely through the pipe section 22 and the head plate 23 extending bore 42 with the pressure-side chamber 30 communicates.
• Supply holes 43 with a diameter of a few 10 microns cross the sleeve 39.
• the axial position of the supply holes 43 is selected so that at the opposite of the head plate 23 reversal point of the piston movement, shown in the figure by a dashed outline of the piston 25, the supply holes 42nd in the amount of the central portion 33 of the piston, while at the head plate 23 facing reversal point of the piston movement, an axial overlap of the positions of the supply holes 43 and the piston 25 need not necessarily be given.
• the overpressure in the compression chamber 26 is sufficient to maintain a gas flow through the gap 36 sufficient for the desired bearing action.
• a hard coating as described above can also be provided in this embodiment on the piston 25 and / or the pipe section 22 to Reibverschl formulate each time the compressor, when the pressure in the chamber 30 is not sufficient to unfold at the supply holes 43 bearing effect , to avoid.
• FIG. 4 shows a section analogous to FIGS. 1 and 3 through a third embodiment of the compressor according to the invention.
• the cap 24, the head plate 23 and the piston 25 are identical to those shown in Fig. 1.
• the interior of the pipe section 22 is extended only at its end facing away from the head plate 23, and in the extension of a sleeve 44 is inserted, which abuts a shoulder 48 of the extension and the inner surface with the inner surface of the unexpanded portion of the pipe section 22 is flush.
• Pipe 22 and sleeve 44 define an annular channel 45 which communicates via a bore 42 with the pressure-side chamber 30.
• FIG. 5 shows a frontal view of the sleeve 44. It can be seen that in an end face 46 of the sleeve, which rests in the mounted state on a shoulder bounding the expansion of the tubular piece 22, uniformly distributed notches 47 are embossed in the circumferential direction. Unlike holes, the notches 47 can be realized with a width and depth of a few 10 microns and a practically arbitrary length simultaneously and with little effort. Together with the shoulder 48 of the pipe section 22 they limit

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
• Compressor (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=38779739

Family Applications (1)

Country Status (6)

Families Citing this family (16)

Citations (4)

Family Cites Families (13)

• 2006
  • 2006-11-07 DE DE102006052430A patent/DE102006052430A1/de not_active Withdrawn
• 2007
  • 2007-10-31 US US12/513,702 patent/US20100021323A1/en not_active Abandoned
  • 2007-10-31 RU RU2009119391/06A patent/RU2432497C2/ru not_active IP Right Cessation
  • 2007-10-31 EP EP07822074A patent/EP2092195A1/de not_active Withdrawn
  • 2007-10-31 WO PCT/EP2007/061726 patent/WO2008055826A1/de active Application Filing
  • 2007-10-31 CN CNA2007800414128A patent/CN101535644A/zh active Pending

Patent Citations (4)

Non-Patent Citations (1)

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