EP0441630B1 - Méthode pour le traitement de la surface d'un axe rotatif d'un appareil de compression d'un fluide - Google Patents

Méthode pour le traitement de la surface d'un axe rotatif d'un appareil de compression d'un fluide Download PDF

Info

Publication number
EP0441630B1
EP0441630B1 EP19910301008 EP91301008A EP0441630B1 EP 0441630 B1 EP0441630 B1 EP 0441630B1 EP 19910301008 EP19910301008 EP 19910301008 EP 91301008 A EP91301008 A EP 91301008A EP 0441630 B1 EP0441630 B1 EP 0441630B1
Authority
EP
European Patent Office
Prior art keywords
rotational shaft
temperature
furnace
layer
shaft
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.)
Expired - Lifetime
Application number
EP19910301008
Other languages
German (de)
English (en)
Other versions
EP0441630A1 (fr
Inventor
Izumi C/O Intellectual Property Division Onoda
Kenji C/O Intellectual Property Division Komine
Wataru C/O Intellectual Property Division Ikeda
Akira C/O Intellectual Property Div. Morishima
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.)
Toshiba Corp
Toshiba AVE Co Ltd
Original Assignee
Toshiba Corp
Toshiba AVE Co Ltd
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
Priority claimed from JP2030591A external-priority patent/JP2542719B2/ja
Priority claimed from JP4780290A external-priority patent/JPH03249167A/ja
Application filed by Toshiba Corp, Toshiba AVE Co Ltd filed Critical Toshiba Corp
Publication of EP0441630A1 publication Critical patent/EP0441630A1/fr
Application granted granted Critical
Publication of EP0441630B1 publication Critical patent/EP0441630B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/80—After-treatment

Definitions

  • the present invention relates, in general, to methods for treating the surface of a slide movable member.
  • the invention relates to a method for treating the surface of a rotational shaft used in a fluid compressing apparatus.
  • an inverter unit is used in the air conditioning system to expand the rotational speed of the compressor.
  • the rotational speed of the compressor is widely changed, as compared with the air conditioning apparatus which is operated with a conventional commercial frequency, i.e., 60 Hz, and furthermore the compressor is operated at an increased air conditioning load because of the increase in the space to be air-conditioned at one time.
  • high wear-resisting and adhesion-resisting abilities of the rotational shaft of the compressor are required to endure the above-described operational conditions.
  • the rotational shaft transmits a driving force from a driving section, i.e., a motor, to a compressing section and is under a high temperature caused by a slide-contact with bearings.
  • a phosphate treatment, a molybdenum disulfide treatment, and a boron nitridation treatment are well known as a method for enhancing the slide-moving ability of the bearing. Such treatments form a specific layer on the surface of the rotational shaft.
  • the above-described treatments improve the adhesion-resisting property of the rotational shaft at the operation of an increased load condition and also improve the initial fitting between the rotational shaft and the bearings.
  • the above-described treatments form a relatively soft specific layer on the surface of the rotational shaft or the bearings.
  • the wear of the rotational shaft or bearings may be caused by the load fluctuation of the rotational shaft or the decrease in the thickness of the lubricating oil film formed between the rotational shaft and the bearings.
  • the use of a material having a high hardness, or the enhancement of the surface hardness of the rotational shaft by a surface treatment are effective.
  • the high hardness of the material has a drawback in its mechanical processing.
  • a high frequency quenching a cementation, a nitridation treatment, a boronidation treatment (treatment with boron), a siliconizing, etc.
  • a high frequency quenching a cementation, a nitridation treatment, a boronidation treatment (treatment with boron), a siliconizing, etc.
  • the above-described treatments are carried out at a fairly high temperature.
  • the temperature of the cementation is about 780 °C
  • the temperature of the nitridation treatment is between five and six hundred degrees centigrade (°C).
  • Another surface treatment may be an ion nitridation treatment. Since the ion nitridation treatment is carried out at a relatively low temperature, as compared with other nitridation treatments, changes in the dimensional accuracy is small before and after the ion nitridation treatment is performed. Thus, the ion nitridation treatment is suitable for slide-movable parts on which a precision finishing is performed. However, such an ion nitridation treatment is unsuitable for parts, e.g., a rotational shaft, having a slit or a complicated structure.
  • a glow discharge is carried out in a furnace in which a nitrogen gas or a gas mixing a nitrogen gas with a hydrogen gas is filled at an atmospheric pressure of 1 ⁇ 10 (torr) (130-1300Pa).
  • a nitrogen gas or a gas mixing a nitrogen gas with a hydrogen gas is filled at an atmospheric pressure of 1 ⁇ 10 (torr) (130-1300Pa).
  • Occurrence of the hollow cathode discharge depends on a degree of vacuum pressure in the furnace and the diameter of a hole, the width of a slit or the size of a gap.
  • the hollow cathode discharge tends to occur if a degree of vacuum pressure in the furnace is decreased and also if the diameter of the hole is constant over the entire length of the hole.
  • Patent Abstracts of Japan, vol. 8, No. 93 (C-220)[1530] discloses a surface hardening and nitriding method of steel material. The parts of the hardened material are subjected to stress relieving annealing. The parts are then subjected to a soft nitriding treatment (soft nitriding at 580-610°C) and an oxide film treatment.
  • a method for treating the surface of a rotational shaft used in a fluid compressing apparatus the shaft having at least one lateral hole formed in a portion of said rotational shaft, wherein said at least one hole has a diameter which is between 3 and 20 mm, and/or having at least one depressed portion formed in a circumferential surface of said rotational shaft, wherein the width of said at least one depressed portion is between 3 and 20 mm, and/or having an oil passage having a large diameter path formed in said rotational shaft
  • the method including the steps of: providing the rotational shaft made of an iron-containing metal having a transformation temperature; annealing the rotational shaft at a temperature selected between a first temperature equal to a prescribed temperature determined by adding about 50 degrees centigrade to a temperature of a subsequent ion nitridation treatment and a second temperature equal to the transformation temperature of the iron-containing metal; forming an iron nitride layer in the surface of the rotational shaft by performing the ion nitrid
  • the method may further comprise the sub steps of exhausting air in a furnace in which the rotational shaft is disposed, flowing a prescribed gas selected from an ammonia gas, a nitrogen gas and a mixture of a hydrogen gas and a nitrogen gas into the furnace, intermittently applying a prescribed DC voltage between the rotational shaft and the wall surface of the furnace so that the rotational shaft acts as a cathode and the wall surface of the furnace acts as an anode to form an ion sheath on the surface of the rotational shaft, increasing the temperature of the rotational shaft, executing the ion nitridation treatment to the surface of the rotational shaft, and decreasing the temperature of the rotational shaft to the temperature at which an oxidation of the rotational shaft does not progress, as an inert gas is entered into the furnace.
  • a fluid compressing apparatus 21 includes a driving unit 23 located at an upper portion in a casing 25 and a compressing unit 27 arranged at a lower portion in casing 25.
  • Driving unit 23 includes a motor 29 composed of a stator 29a and a rotor 29b.
  • Compressing unit 27 includes a pair of cylinders 31a and 31b.
  • a rotational shaft 33 fixed to rotor 29b extends through the pair of cylinders 31a and 31b and is rotatably supported by both a main bearing 35 disposed at the upper side of the pair of cylinders 31a and 31b and an auxiliary bearing 37 disposed at the lower side of the pair of cylinders 31a and 31b.
  • a main shaft portion 33a of rotational shaft 33 is supported by main bearing 35 and an auxiliary shaft portion 33b thereof is supported by auxiliary bearing 37.
  • a portion of rotational shaft 33 exposed in one of the cylinders 31a is provided with a first crank 39a and a portion of rotational shaft 33 exposed in the other cylinder 31b is provided with a second crank 39b.
  • a first roller 41a is fixed on the outer surface of first crank 39a and a second roller 41b also is fixed on the outer surface of second crank 39b.
  • a partition plate 43 is interposed between the pair of cylinders 31a and 31b.
  • a first compressing chamber 45a is defined by main bearing 35, partition plate 43 and one of the cylinders 31a.
  • a second compressing chamber 45b also is defined by auxiliary bearing 37, partition plate 43 and the other cylinder 31b.
  • a pair of intake openings 47a and 47b is respectively formed in the corresponding outer surface of the pair of cylinders 31a and 31b.
  • One end of a pair of pipes 49a and 49b is inserted into the corresponding intake openings 47a and 47b and the other end thereof is inserted into an accumulator 51, which separates a liquid refrigerant and a gaseous refrigerant.
  • a first valve cover 53a is formed at main bearings 35 and a second valve cover 53b also is formed at auxiliary bearing 37 to temporarily receive therein a pressurized refrigerant output from each compressing chamber 45a, 45b.
  • an oil passage 55 is formed in rotational shaft 33 along its longitudinal direction.
  • the lower end portion 37a of auxiliary bearing 37 and the opening 33a of the extended end of rotational shaft 33 is closed with a plate 57.
  • Outer surface of plate 57 is supported by second valve cover 53b to receive a force of rotational shaft 33 in a thrust direction.
  • An oil intake opening 59 is formed at the center of plate 57 to supply a lubricating oil stored in casing 25 to each slide-contact portion of rotational shaft 33 through oil passage 55 formed in rotational shaft 33.
  • Oil passage 55 is formed in rotational shaft 33 so that it has a large diameter path 55a extending from opening 33a to a mid-portion above the location of first crank 39a and a relatively small diameter path 55b from the mid-portion to the upper end thereof.
  • the upper end portion of large diameter path 55a corresponds to a location at which rotational shaft 33 is rotatably supported by main bearing 35 to supply a sufficient amount of lubricating oil to each slide-contact portion of rotational shaft 33.
  • a conventional oil pump mechanism 61 is provided in large diameter path 55a of oil passage 55 to ensure a sufficient supply of lubricating oil to the upper end of rotational shaft 33.
  • a first lateral hole 63a is formed in a portion of rotational shaft 33 corresponding to main bearing 35 to supply lubricating oil from large diameter path 55a to main bearing 35 therethrough.
  • a second lateral hole 63b is formed through first crank 39a to supply lubricating oil from large diameter path 55a to the surface of first crank 39a therethrough.
  • a third lateral hole 63c also is formed through second crank 39b to supply lubricating oil from large diameter path 55a to the surface of second crank 39b therethrough.
  • the above-described rotational shaft 33 is made of an iron system metal material.
  • the iron system metal material may be foundries, e.g., a flaky graphite cast iron, a spheroidal graphite cast iron, etc., a steel, e.g., a nitrified steel, a carbon steel, etc., or an iron system sintered material.
  • an annealing process for eliminating a distortion (hereinafter referred to as an annealing process) is performed on rotational shaft 33 at a prescribed temperature in step ST1a.
  • An internal stress is caused by a difference in the cooling speed of each different portion of rotational shaft 33 when rotational shaft 33 is cast .
  • a processing distortion in rotational shaft 33 by a rough machining process also is eliminated.
  • the prescribed temperature is located between a temperature obtained by adding 50 degrees centigrade (°C) to an ion nitridation treatment temperature, e.g., 450 ⁇ 550 degrees centigrade (°C), and a transformation temperature of the above-described iron system metal material.
  • the annealing may be carried out in an atmosphere of an inert gas or in the air.
  • rotational shaft 33 is taken out from the furnace.
  • an oxidation progresses in the surface of rotational shaft 33.
  • This oxidation occurs in the surface of rotational shaft 33 which is annealed not only in the air but also in an inert gas.
  • An oxide produced in the surface of rotational shaft 33 causes the loading or the glazing of a grinding wheel during the grinding process, and thus the grinding ability of the grinding wheel is decreased.
  • the oxidation layer formed in the surface of rotational shaft 33 causes unevenness of the surface of rotational shaft 33, and a concentration of discharge may occur during the sputtering process resulting in a prolonging of the period of the sputtering process.
  • the wire-buffing is carried out on the surface of rotational shaft 33 to remove the oxidation layer from the surface of rotational shaft 33 in step ST1b.
  • the ion nitridation treatment is carried out on rotational shaft 33 in step ST1c. Detail processes of the ion nitridation treatment are shown in FIGURE 4.
  • the ion nitridation treatment includes a vacuum exhaustion process (step ST2a), a sputtering process (step ST2b), a temperature increase process (step ST2c), a nitridation process (step ST2d) and a temperature decrease process (step ST2e).
  • step ST2a In the vacuum exhaustion process (step ST2a),
  • rotational shaft 33 is disposed in the vacuum reaction furnace, and the exhausting operation is carried out at an order of less than 0.1 (Torr) (13Pa). At this time, no air leakage from the vacuum reaction furnace should be confirmed.
  • step ST2b an ammonia gas, a nitrogen gas or a mixture of the ammonia gas and the nitrogen gas is entered into the vacuum reaction furnace.
  • DC voltage is intermittently applied between rotational shaft 33 and the wall surface of the vacuum reaction furnace at an interval of several »sec ⁇ several hundreds msec.
  • rotational shaft 33 acts as a cathode and the wall surface of the vacuum reaction furnace is grounded.
  • the above-described DC voltage is applied between rotational shaft 33 and the wall surface of the vacuum reaction furnace so that the wall surface of vacuum reaction furnace acts as an anode.
  • ammonium ions or nitrogen ions impinge on the surface of rotational shaft 33 to clean the surface of rotational shaft 33.
  • Oil on the surface of rotational shaft 33 is driven out and is exhaused to the outside of the reaction region, e.g., the vacuum reaction furnace.
  • the discharge is stably generated between rotational shaft 33 and the wall surface of the vacuum reaction furnace and the thin ionic sheath is finally formed on the entire surface of rotational shaft 33.
  • step ST2c the applied DC voltage and the pressure in the vacuum reaction furnace are gradually increased to increase the impinging energy and the increase of impinging ions results in an increase in the temperature of rotational shaft 33.
  • the nitridation temperature is set at 450 ⁇ 550 degrees centigrade (°C).
  • the iron elements which are driven out from the surface of rotational shaft 33 by nitrogen ions are joined to other nitrogen ions to adhere on the surface of rotational shaft 33, as an iron nitride.
  • a chemical compound layer is formed on the surface of rotational shaft 33 by the progress of the above-described adhesion.
  • iron elements joined to the nitrogen ions are not sufficiently adhered on the surface of rotational shaft 33 if the nitridation temperature is low.
  • a diffusion layer produced by diffusing a part of nitrogen of the iron nitride adhered on the surface of rotational shaft 33 toward the inside of rotational shaft 33 also is rarely formed in the surface of rotational shaft 33. If the nitridation process is carried out at a temperature less than 450 degrees centigrade (°C), the wear-resisting ability of rotational shaft 33 is unsatisfied. If the nitridation temperature is excessively low, the form of the chemical compound layer and the diffusion layer on the surface of rotational shaft 33 is insufficient, as described above, and the composition of the chemical compound layer, e.g., a ⁇ ′-phase and ⁇ -phase ratio, is changed.
  • the nitridation temperature is greater than 550 degrees centigrade (°C)
  • the nitridation to rotational shaft 33 progresses sufficiently.
  • step ST2e the temperature of rotational shaft 33 is decreased to a temperature at which no oxidation on the surface of rotational shaft 33 progresses, and the oxidation of the surface of rotational shaft 33 is avoided by flowing an inert gas, e.g., nitrogen gas, into the vacuum reaction furance.
  • an inert gas e.g., nitrogen gas
  • the removing process is carried out after the above-described ion nitridation process has been completed to remove the unreacted remains in the surface of rotational shaft 33 (ST1d).
  • the unreacted remains include a defective nitrified portion of rotational shaft 33 and the outer-most surface layer of rotational shaft 33 which has not been densified during the ion nitridation process.
  • the defective nitrified portion is formed in the surface of rotational shaft 33.
  • step ST1d a ball burnishing, a so-called barrel polishing, is performed on the surface of rotational shaft 33, for example.
  • a phosphate film forming process is executed in step ST1e.
  • the phosphate film forming process may be a conventional manganese phosphate treatment.
  • Base metal 101 shown in FIGURE 5(a) may be an iron system metal material, e.g., foundries, a steel or an iron system sintered material.
  • a chemical compound layer 103 is formed on the surface of base metal 101 and an unreacted remains 105 also is produced in the outer-most surface of chemical compound layer 103, as shown in FIGURE 5(b).
  • a diffusion layer, i.e., a nitrogen diffusion region, 107 is also produced in base metal 101.
  • the above-described chemical compound 103 is composed of a ⁇ ′-phase (Fe4N) and an ⁇ -phase (Fe 2 ⁇ 3 N).
  • the thickness of chemical compound layer 103 is set at about one ⁇ several »m, and the thickness of diffusion layer 107 is set at about ten »m.
  • unreacted remains 105 of the outer-most surface of chemical compound layer 103 are removed, as shown in FIGURE 5(c). If unreacted remains 105 are not removed, unreacted remains 105 cause the adhesion between rotational shaft 33 and bearings 35 and 37. If the phosphate film is formed on chemical compound layer 103 without removing unreacted remains 105, the phosphate film tends to be peeled from chemical compound layer 103.
  • Base metal 101 is dipped into a phosphate treating liquid, e.g., a manganese phosphate treating liquid, after unreacted remains 105 are removed, and is dried to form phosphate film 109 on the surface of chemical compound layer 103, as shown in FIGURE 5(d).
  • a phosphate treating liquid e.g., a manganese phosphate treating liquid
  • a spheroidal graphite cast iron is used as a base metal, the oscillational rotation of rotational shaft 33 caused by a high frequency driving of the fluid compressing apparatus is decreased because of a high stiffness thereof. Since the wear-resisting ability of base metal 101 is enhanced by the above-described surface treatment, the stiffness and the manufacturing cost of a material of the base metal is preferentially considered rather than the wear-resisting ability of the material when the material of the base metal is determined.
  • a STKM Carbon Steel Tube for Machine Structural Purposes
  • a SCM Chromium Molybdenum Steel
  • G 4105 may also be used as a base metal.
  • the temperature of the ion nitridation treatment is low, as compared with that of other nitridation treatments, e.g., a sulfonitrizing treatment, a gas soft nitriding treatment, etc.
  • a polishing of the hardened outer-most surface of the base metal is not needed after the nitridation treatment is performed. Selecting a usable rotational shaft from a plurality of nitrified rotational shafts also is not needed after the final polishing and the ion nitridation treatment are performed.
  • the rotational shaft on which the ion nitridation treatment is performed has a good wear-resisting property and also a high mass-productivity. Furthermore, since the phosphate film is formed on the surface of chemical compound layer 103 of rotational shaft 33 after unreacted remains 105 of chemical compound layer 103 are removed, the adhesion between rotational shaft 33 and bearings 35 and 37 is avoided. The abrasion of the surface of rotational shaft 22 caused by the slide-contact between rotational shaft 33 and bearings 35 and 37 is also avoided. An initial fitting of rotational shaft 33 to bearings 35 and 37 also is enhanced. This is because the phosphate film is relatively soft, as compared with chemical compound layer 103.
  • the thickness of chemical compound layer 103 is set at less than 1 »m, and the thickness of diffusion layer 107 is set at about 30 to 100 »m.
  • the above-described diffusion layer 107 and chemical compound layer 103 are once formed on the surface of base metal 101 (rotational shaft 33) by the ion nitridation treatment. Then, the above-described removing process is performed to remove chemical compound layer 103 including the outer-most layer of diffusion layer 107. After that, the phosphate film 109 is formed on the surface of diffusion layer 107. Since, diffusion layer 107 is relatively soft compared with chemical compound layer 103, a post processing can be performed to base metal 101 after diffusion layer 107 is formed in the surface of base metal 101.
  • a 3 »m chemical compound layer and a 20 »m diffusion layer were formed on the surface of the rotational shaft.
  • the removing process was carried out for several minutes to remove the unreacted remains of the outermost surface of the chemical compound layer.
  • the manganese phosphate treatment was further performed on the chemical compound layer of the rotational shaft to form a manganese phosphate film on the surface of the chemical compound layer at several »m.
  • FIGURES 7(a) and 7(b) show relative slide-moving characteristics of main and auxiliary shaft portions 33a and 33b of the rotational shaft 33 and main and auxiliary bearings 35 and 37 shown in FIGURE 1.
  • FIGURE 7(a) shows an amount of each wear depth of main and auxiliary shaft portions 33a and 33b and main and auxiliary bearings 35 and 37.
  • FIGURE 7(b) shows each surface roughness of main and auxiliary shaft portion 33a and 33b and main and auxiliary bearings 35 and 37.
  • the geometrical symbol ( ⁇ ) indicates results of a first experiment in which the rotational shaft treated by the ion nitridation process was used under the above-described first condition.
  • the geometrical symbol ( ⁇ ) indicates results of a second experiment in which the rotational shaft treated by the ion nitridation process was used under the above-described second condition.
  • the geometrical symbol ( ⁇ ) indicates results of a third experiment in which the conventional rotational shaft which is not treated by the ion nitridation process was used under the first condition, and the geometrical symbol ( ⁇ ) also indicates results of a fourth experiment in which the conventional rotational shaft was used under the second condition for the purpose of the comparison.
  • the rotational shaft the surface of which has diffusion layer 107 shown in FIGURE 6, was practically made by the following conditions.
  • the ion nitridation treatment was carried out on the rotational shaft after the annealing process was performed on the rotational shaft, similar to the above-described processes by which the chemical compound layer finally remains on the surface of the rotational shaft.
  • the removing process is carried out to remove the chemical compound layer and a part of the diffusion layer from the rotational shaft.
  • the chemical compound layer and a part of the diffusion layer at a thickness of 15 »m from the surface of the rotational shaft were removed.
  • the surface hardness of the rotational shaft showed about 500 ⁇ 600 by the Vickers hardness test.
  • the surface hardness of the rotational shaft was enhanced, as compared with the base metal, the surface hardness of which is about 300 in the Vickers hardness.
  • the phosphate film of several »m was finally formed on the diffusion layer of the rotational shaft.
  • FIGURE 8 shows changes in the voltage (a hollow cathode discharge occurring voltage) at different pressures in a reaction furnace when a diameter of hole or a width of slit of the rotational shaft is varied in the ion nitridation treatment.
  • a solid curve PR1 shows changes in the hollow cathode discharge occurring voltage when the pressure in the reaction furnace is ten and several (Torr) (e.g 1300-2600Pa)
  • a solid curve PR2 shows changes in the hollow cathode discharge occurring voltage when the pressure in the reaction furnace is several (Torr) (e.g 130-1300Pa).
  • a solid curve PR3 also shows changes in the hollow cathode discharge occurring voltage when the pressure in the reaction furnace is one (Torr) (130Pa).
  • a range between Ra and Rb shows changes in the voltage in each pressure described above when the temperature in the reaction furnace is maintained at 450 ⁇ 580 degrees centigrade (°C).
  • the voltage drop occurs within a range of 3 ⁇ 20 mm in relation to the diameter of hole or the width of slit of the rotational shaft even if the pressure in the reaction furnace is varied.
  • a hollow cathode discharge phenomenon occurs in the rotational shaft having the hole or the slit of the above-described range when the ion nitridation treatment is performed on the surface of the rotational shaft.
  • first, second and third lateral holes 63a, 63b and 63c are formed in rotational shaft 33.
  • the inner diameter of first lateral hole 63a is 3 ⁇ 20 mm.
  • a first depressed portion 121a is formed in a circumferential surface above first crank portion 39a of rotational shaft 33.
  • a second depressed portion 121b also is formed in a circumferential surface between first and second crank portions 39a and 39b.
  • the width of first and second depressed portions 121a and 121b is about 3 ⁇ 20 mm.
  • a bar-shaped masking pin 123 is inserted into first lateral hole 63a as shown in FIGURE 10(a) to avoid occurrence of the hollow cathode discharge phenomenon.
  • the diameter of the top portion of masking pin 123 is slightly smaller than that of first lateral hole 63a and the diameter of the remaining portion of masking pin 123 is substantially the same as that of first lateral hole 63a.
  • masking pin 123 is easily inserted into or taken out from first lateral hole 63a.
  • First and second ring-shaped masking collars 125a and 125b are fitted into the corresponding first and second depressed portions 121a and 121b, as shown in FIGURE 10(b). Thus, the hollow cathode discharge phenomenon which would occur in first and second depressed portions 121a and 121b can be avoided.
  • First ring-shaped masking collar 125a has an inner diameter slightly smaller than the outer diameter of first circumferential depressed portion 121a.
  • Second ring-shaped masking collar 125b also has an inner diameter slightly smaller than the outer diameter of second circumferential depressed portion 121b.
  • First and second ring-shaped masking collars 125a and 125b respectively have a slit 127a, 127b traversing the surface thereof.
  • first ring-shaped masking collar 125a is elastically attached to first circumferential depressed portion 121a by forcibly extending collar 125a from slit 127a.
  • Second ring-shaped masking collar 125b also is attached to second circumferential depressed portion 121b by the same operation as described above.
  • First and second ring-shaped masking collars 125a and 125b are preferably made of a spring steel.
  • a third depressed portion 121c formed in a circumferential surface of rotational shaft 33 just below second crank portion 39b may be covered with a ring-shaped masking collar (not shown) similar to the above-described first and second ring-shaped masking collars 125a and 125b if the width of third depressed portion 121c is greater than 3 mm.
  • a hollow cathode discharge does not occur because of the masking elements, e.g., pin or collar.
  • the temperature of the surface of rotational shaft 33 defining first lateral hole 63a does not excessively increase during the ion nitridation treatment and the temperature of each surface of rotational shaft 33 defining first and second depressed portions 121a and 121b does not also increase in excess.
  • a partial heat deformation does not occur in the surface of rotational shaft 33.
  • a rod 151 made of a material similar to that of rotational shaft 33 is used to avoid a hollow cathode discharge occurring in large diameter path 55a of oil passage 55 formed in rotational shaft 33.
  • Rod 151 is inserted into large diameter path 55a when the ion nitridation treatment is performed, as shown in FIGURE 11.
  • a curved depressed portion 151a is formed in the circumferential surface of rod 151 opposite to the inner edge of rotational shaft 33 to maintain a suitable distance between the surface of rod 151 and the opening edge of large diameter path 55a.
  • a hollow cathode discharge occuring in large diameter path 55a of rotational shaft 33 is avoided by rod 151 inserted in large diameter path 55a.
  • the temperature in the surface which defines large diameter path 55a does not increase excessively.
  • a partial heat deformation does not occur in the surface of rotational shaft 33 which defines large diameter path 55a.
  • nitrogen ions are uniformly implanted into the outer surface of rotational shaft 33 including an edge surface portion 153 of rotational shaft 33 shown in FIGURE 12.
  • the wear-resisting ability of edge surface portion 153 of rotational shaft 33 is enhanced, and thus edge surface portion 153 of rotational shaft 33 maintains a smooth rotation against plate 57 shown in FIGURE 2 for an extended operational period.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Compressor (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Claims (7)

  1. Un procédé pour traiter la surface d'un arbre rotatif (33) utilisé dans un appareil de compression de fluide (21), l'arbre (33) présentant
    au moins un trou latéral (63a, 63b, 63c) formé dans une partie dudit arbre rotatif (33), dans lequel ledit trou (63a, 63b, 63c) a un diamètre compris entre 3 et 20 mm,
    et/ou présentant
    au moins une partie en creux (121a, 121b, 121c) formée dans une surface circonférentielle dudit arbre rotatif (33), dans lequel la largeur de ladite partie en creux est comprise entre 3 et 20 mm,
    et/ou présentant
    un passage d'huile (55) présentant un trajet de grand diamètre (55a) formé dans ledit arbre rotatif (33),
    le procédé comprenant les opérations consistant à :
    prévoir de réaliser l'arbre rotatif (33) en un alliage métallique à base de fer présentant une température de transformation ;
    procéder à un recuit de l'arbre rotatif (33) à une température choisie entre une première température égale à une température prescrite déterminée en ajoutant environ 50 degrés centigrades à une température d'un traitement de nitruration ionique ultérieur et une seconde température égale à la température de transformation de l'alliage métallique à base de fer ;
    former une couche de nitrure de fer à la surface de l'arbre rotatif (33) en effectuant le traitement de nitruration ionique à une température entre 450 degrés centigrades et 550 degrés centigrades ; et
    former une couche de phosphate sur la couche de nitrure de fer de la surface de l'arbre rotatif (33), où l'orifice (63a, 63b, 63c) et/ou la partie en creux (121a, 121b, 121c) et/ou le trajet de grand diamètre (55a) sont masqués quand le traitement de nitruration ionique est effectué pour former la couche de nitrure de fer sur la surface de l'arbre rotatif (33).
  2. Un procédé selon la revendication 1, comprenant en outre l'opération consistant à retirer une pellicule d'oxyde, produite par l'opération de recuit, de la surface de l'arbre rotatif (33) avant que soit formée la couche de nitrure de fer.
  3. Un procédé selon la revendication 1 ou 2, comprenant en outre l'opération consistant à retirer un résidu n'ayant pas réagi, produit par l'opération de formation de la couche de nitrure de fer, de la surface de la couche de nitrure de fer de l'arbre rotatif (33) avant que soit formée la couche de phosphate.
  4. Un procédé selon la revendication 3, dans lequel la couche de nitrure de fer comprend une couche de diffusion et une couche de composé chimique formée sur la couche de diffusion, la couche de composé chimique étant retirée quand le résidu n'ayant pas réagi est retiré pour mettre à nu la couche de diffusion.
  5. Un procédé selon une revendication précédente quelconque, comprenant en outre la sous-opération consistant à extraire l'air d'un four où est placé l'arbre rotatif (33), faire écouler, dans le four, un gaz prescrit choisi à partir d'ammoniac gazeux, d'azote gazeux et d'un mélange d'hydrogène gazeux et d'azote gazeux, appliquer par intermittence une tension de courant continu prescrite entre l'arbre rotatif (33) et la surface de paroi du four de sorte que l'arbre rotatif (33) agit comme cathode et que la surface de paroi du four agit comme anode pour former une gaine d'ions sur la surface de l'arbre rotatif (33), augmenter la température de l'arbre rotatif (33), exécuter le traitement de nitruration ionique sur la surface de l'arbre rotatif (33), et diminuer la température de l'arbre rotatif (33) à la température à laquelle une oxydation de l'arbre rotatif (33) ne progresse pas, au fur et à mesure qu'un gaz inerte est introduit dans le four.
  6. Un procédé selon une revendication précédente quelconque, dans lequel l'arbre rotatif (33) présente une partie de bord d'ouverture (153) et dans lequel le passage d'huile (55) est masqué par une tige allongée (151) insérée à force dans le passage d'huile (55) par l'intermédiaire de la partie de bord d'ouverture (153).
  7. Un procédé selon la revendication 6, dans lequel la tige allongée (151) présente une partie courbe en creux (151a) à sa surface périphérique et dans lequel la tige allongée (151) est insérée dans le passage d'huile (55), de sorte que la partie courbe en creux (151a) est placée à l'opposé de la partie de bord d'ouverture (153) de l'arbre rotatif (33).
EP19910301008 1990-02-09 1991-02-07 Méthode pour le traitement de la surface d'un axe rotatif d'un appareil de compression d'un fluide Expired - Lifetime EP0441630B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2030591A JP2542719B2 (ja) 1990-02-09 1990-02-09 コンプレッサ用回転軸およびその製造方法
JP30591/90 1990-02-09
JP4780290A JPH03249167A (ja) 1990-02-28 1990-02-28 圧縮機用回転軸の表面処理方法
JP47802/90 1990-02-28

Publications (2)

Publication Number Publication Date
EP0441630A1 EP0441630A1 (fr) 1991-08-14
EP0441630B1 true EP0441630B1 (fr) 1995-04-26

Family

ID=26368973

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910301008 Expired - Lifetime EP0441630B1 (fr) 1990-02-09 1991-02-07 Méthode pour le traitement de la surface d'un axe rotatif d'un appareil de compression d'un fluide

Country Status (2)

Country Link
EP (1) EP0441630B1 (fr)
DE (1) DE69109145T2 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0694629A3 (fr) * 1994-07-27 1998-09-23 Balzers Sa Objet résistant à la corrosion et l'usure procédé de sa fabrication et installation de traitement sous vide

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE742505C (de) * 1941-01-24 1943-12-04 Vormals Skodawerke Ag Verfahren und Abdeckmittel zum oertlichen Schutz zu nitrierender Metalloberflaechen
US2851387A (en) * 1957-05-08 1958-09-09 Chapman Valve Mfg Co Method of depassifying high chromium steels prior to nitriding
US3397092A (en) * 1964-02-27 1968-08-13 Hooker Chemical Corp Corrosion-resistant coatings
DE2853542A1 (de) * 1978-12-12 1980-06-26 Kodak Ag Verfahren zur oberflaechenbehandlung von werkstuecken aus stahl
GB8310102D0 (en) * 1983-04-14 1983-05-18 Lucas Ind Plc Corrosion resistant steel components
JPS60153455A (ja) * 1984-01-23 1985-08-12 Nippon Piston Ring Co Ltd 鋼製ピストンリング
FR2604188B1 (fr) * 1986-09-18 1992-11-27 Framatome Sa Element tubulaire en acier inoxydable presentant une resistance a l'usure amelioree

Also Published As

Publication number Publication date
DE69109145T2 (de) 1995-08-31
DE69109145D1 (de) 1995-06-01
EP0441630A1 (fr) 1991-08-14

Similar Documents

Publication Publication Date Title
US5582414A (en) Sliding member and method for manufacturing the same
US4486247A (en) Wear resistant steel articles with carbon, oxygen and nitrogen implanted in the surface thereof
US5449547A (en) Hard coating material, sliding member coated with hard coating material and method for manufacturing sliding member
EP1087031B1 (fr) Couche dure, élément de glissement recouvert par elle et son procédé de fabrication
US6656293B2 (en) Surface treatment for ferrous components
EP0408168A1 (fr) Procédé pour le prétraitement préalable de matériaux métalliques et procédé pour la nitruration d'acier
US8479396B2 (en) Method for hardening running surfaces of roller bearing components
WO2005100810A1 (fr) Procede de finition des surfaces critiques d'un roulement
US6214479B1 (en) Covered member and method of producing the same
KR101892531B1 (ko) 철계 금속의 질화방법
JP2002161856A (ja) シャフトおよびシャフトの製造方法
EP0441630B1 (fr) Méthode pour le traitement de la surface d'un axe rotatif d'un appareil de compression d'un fluide
EP1138795B1 (fr) Materiau brut pour elements de roulement
EP1837418A1 (fr) Revêtement en carbone à dureté élevée
JP3593221B2 (ja) 摺動部品の表面処理方法
WO2000075522A1 (fr) Dispositif a palier et procede de fabrication d'un tel dispositif
JPH1089345A (ja) 動圧軸受
KR930009989B1 (ko) 압축기용 회전축의 표면처리방법
JP3129817B2 (ja) ピストンリング
JPS6345479A (ja) 斜板式圧縮機
JPH07286589A (ja) 圧縮機用摺動部材
JPS5993870A (ja) 回転圧縮機用ベ−ンの製造方法
JP3464651B2 (ja) エアーモータ用部材
JP3954739B2 (ja) 窒素含有Ｃｒ被膜の製造方法
JP4877502B2 (ja) 窒素含有Ｃｒ被膜およびこの被膜を有する機械部材

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19910226

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE IT

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: TOSHIBA AVE CO., LTD

Owner name: KABUSHIKI KAISHA TOSHIBA

17Q First examination report despatched

Effective date: 19930705

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE IT

REF Corresponds to:

Ref document number: 69109145

Country of ref document: DE

Date of ref document: 19950601

ITF It: translation for a ep patent filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19970214

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19981103

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050207