Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
  • F16C33/02—Parts of sliding-contact bearings
  • F16C33/04—Brasses; Bushes; Linings
  • F16C33/20—Sliding surface consisting mainly of plastics
  • F16C33/201—Composition of the plastic
• • 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
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
  • F04B1/0404—Details or component parts
  • F04B1/0413—Cams
• • 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
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
  • F04B1/0404—Details or component parts
  • F04B1/0426—Arrangements for pressing the pistons against the actuated cam; Arrangements for connecting the pistons to the actuated cam
• • 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
  • F05C2201/00—Metals
  • F05C2201/04—Heavy metals
  • F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
• • 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
  • F05C2225/00—Synthetic polymers, e.g. plastics; Rubber
• • 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
  • F05C2225/00—Synthetic polymers, e.g. plastics; Rubber
  • F05C2225/12—Polyetheretherketones, e.g. PEEK
• • 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 invention concerns an improved friction bearing for hy- draulic machines, more advantageously with radial cylinders, and a hydraulic machine equipped with said bearing, that is a special configuration of the support device of the thrusts between the crank and the pistons which slide on the former, to generate or receive the torque from the drive shaft; in particular for bear- ings used in high-speed rotating hydraulic machines which require the reduction of the overall dimensions of the machine.
• Prior art includes various types of friction bearings, hydrostatic sliding on the crank or oscillating on a ring interposed between these pistons and the rotating bearing on the crank. Nevertheless, the adoption of rolling-contact bearings is not always possible because it makes the crank cumbersome and the hydraulic machine is consequently overly big in proportion to the displacement. Thus, only the use of friction bearings makes it possible to keep down the overall dimensions of the machine.
• Prior art further includes the use of bearings made of higher resistance plastics; among these materials the following have proven suitable: laminated phenolic plastic (HDV of DIN stan- dards), KEVLAR (brand name) or also VESPEL (brand name manufactured by Dupont); layers of polyetheretherketone (PEEK) or MELDIN (brand name manufactured by Furon) have also been used with equal results; these latter have been used in thin layers anchored by a layer of sintered foam metal.
• laminated phenolic plastic HDV of DIN stan- dards
• KEVLAR brand name
• VESPEL brand name manufactured by Dupont
• layers of polyetheretherketone (PEEK) or MELDIN (brand name manufactured by Furon) have also been used with equal results; these latter have been used in thin layers anchored by a layer of sintered foam metal.
• prior art includes the technique of using shoes made of a material which is softer than the sliding surface on the hub; in any case the particles which are not trapped by the filter, be- cause smaller than the filtering capacity of the same, become em- bedded and remain imprisoned in the said soft material of the shoe grating on and damaging the surface of the hub on which they are rubbed by the said shoe, even if this use surface has a hardness of 60 HRc.
• Said prior art is susceptible to additional improvements with regards to the possibility of finding a definitive and high-efficiency, as well as extremely economical, configuration which makes it possible to carry out the said anti-friction plain bearings which carry out the optimum operation with regards to the impurities and to the elimination of the heat generated in the process of sliding.
• a friction bearing for hydraulic machines comprising a surface in contact and sliding on the surface of the crank, the said surface is carried out on an element inserted in ferrous material interposed between said crank and the piston or its con- necting rod, there is a layer inserted in anti-friction plastic material anchored solidly on this by a layer in sintered metal, characterized by this, which has a layer in anti-friction plastic - material with a minimum thickness but which is slightly greater than the maximum dimension of the particles not captured by the filter of the hydraulic circuit where the hydraulic machine is in- serted; has in addition the thickness of the element in ferrous material of this bearing between 0.4 and 4% of the sliding diameter on the hub of the crank.
• Adopting in a further and preferred embodiment: the hardness of the slide surface of the hub of the crank at the minimum value of 80 HRc.
• Adopting in a second preferred embodiment: the thickness of the said layer of anti-friction plastic material between 1/100 and 12/100 of a millimeter; and the thickness of the said layer of anchorage sintered metal between 10/100 and 40/100 of a millimeter.
• the said antifriction plastic material made of polyetheretherketone (PEEK) .
• Adopting in a further and preferred embodiment: the thickness of the said layer of anti-friction plastic material between 8/100 and 9/100 of a millimeter.
• Adopting in a further and preferred embodiment: the thickness of the said layer of anchorage sintered metal between 21/100 and 23/100 of a millimeter.
• Adopting also, in a successive embodiment: the thickness of the said element in interposed ferrous material between 12/10 and 13/10 of a millimeter excluding the thickness of the anti-friction plastic material layer and the anchoring sintered layer.
• Figure 1 is a partial section of the friction bearing according to the invention
• Figure 2 is a schematic longitudinal cut-away view of a radial cylinders hydraulic machine with connecting rods in which it is very convenient to use the bearing in the contact between the shoe of the connecting rod and the surface of the crank
• Figure 3 is a schematic transverse cut-away of the hydraulic machine in Figure 2
• Figure 4 is the plan view of an element interposed between the said shoe of the connecting rod and the surface of the crank
• Figure 5 is the section V-V of Figure 4.
• Figure 1 shows the layers of the interposed ferrous element 1, on which is present the sintered layer 2 for the anchorage of the layer of anti-friction plastic material 3. This element 4 intend- ed collectively is interposed in the hydraulic machine 5, of Figure 2, between the hub 6 and the base 7 of the connecting rod 8, to connect the corresponding piston 9 to crank 10.
• Figure 4 shows the tubs 11 to anchor the said interposed element 4 to the base 7 of the connecting rod 8 to carry out the thrust R on the surface of the said hub 6, the lubrication hole 12 is also visible.
• the filter employed had the usual filtering capacity of 60 ⁇ m, that is with the maximum dimension of the particles released equal to 6/100 of a millimeter, in other words slightly less than the thickness of the layer of PEEK.
• the hub 6 had a 90 mm slide diameter of the shoe. After many hours of operation the slide surface of the hub 6 of the crank 10 did not show signs of grooving typical of the anti-friction shoes known in the prior art.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Sliding-Contact Bearings (AREA)
• Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=32321391

Family Applications (1)

Country Status (3)

Families Citing this family (2)

Family Cites Families (5)

• 2002
  • 2002-11-18 CN CN02829917.5A patent/CN1701185A/zh active Pending
  • 2002-11-18 EP EP02793323A patent/EP1563196A1/en not_active Withdrawn
  • 2002-11-18 WO PCT/IT2002/000731 patent/WO2004046572A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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