Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
  • B23P11/00—Connecting or disconnecting metal parts or objects by metal-working techniques not otherwise provided for 
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
  • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/02—Valve drive
  • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
  • F01L1/047—Camshafts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
  • B23P2700/00—Indexing scheme relating to the articles being treated, e.g. manufactured, repaired, assembled, connected or other operations covered in the subgroups
  • B23P2700/02—Camshafts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
  • F01L1/02—Valve drive
  • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
  • F01L1/047—Camshafts
  • F01L2001/0471—Assembled camshafts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L2303/00—Manufacturing of components used in valve arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
  • F01L2303/00—Manufacturing of components used in valve arrangements
  • F01L2303/01—Tools for producing, mounting or adjusting, e.g. some part of the distribution

Definitions

• the present invention relates to a method for manufacturing a shaft with shaped profile and to the shaft with shaped profile made by means of said method.
• a shaft with shaped profile comprises a bar and annular elements fixed to the bar.
• the method for manufacturing a shaft with shaped profile comprises, for each annular element, the steps of: defining the housing of an annular element; knurling a tube at the housing defined; and fixing the annular element by interference in the housing.
• the process of knurling of the tube presents the disadvantage of being very sensitive to the variations of diameter of the tube.
• the knurling process requires the tube to have a diameter defined in a highly precise way, i.e., so that it falls within a very narrow range of values.
• a knurl will be obtained that could give rise to a poor fixing between the annular element and the tube, not guaranteeing transmission of the torque in an effective way.
• the aim of the present invention is to provide a method for manufacturing a shaft with shaped profile that will reduce the drawback of the known art.
• a method for manufacturing a shaft with shaped profile comprising the steps of:
• a manufacturing method which enables manufacture of a shaft with shaped profile that is more tolerant to the dimensional variations of the bar as compared to the prior art. Moreover, the manufacturing method is versatile and can be easily adapted to shafts of different sizes. In addition, since the manufacturing method is very versatile, it is advantageous even for low volumes of production.
• the method comprises the step of providing at least one tooth within the annular element along an inner face that delimits the opening.
• the method comprises the step of providing a plurality of teeth within the annular element, distributed about the second axis so as to form an annular toothing preferably by broaching .
• the method comprises the step of making the bar from a tube preferably obtained by wire drawing.
• the step of depositing material on the bar is carried out with an additive manufacturing process.
• the additive manufacturing process includes depositing metal powder on the bar, and fixing the metal powder on the bar by a heat source.
• the additive manufacturing process includes using a metal- powder injector.
• the method comprises the step of forming in the coupling stretch at least one projection, which extends in height so as to be radial to the first axis.
• the method comprises the step of measuring at least one dimension of the projection during deposition of material so as to adjust the deposition of material according to the at least one measured dimension of the projection.
• the method comprises the step of forming a projection that extends about the first axis so as to define an annular projection.
• the method comprises the step of forming the projection having a helix shape about the first axis.
• the step of forming the projection is simplified.
• the projection is obtained through a single continuous passage in the coupling stretch so as to reduce production time.
• the fixing, obtained by interference, between the annular element and the bar presents a very high performance in so far as it develops an excellent grip between the annular element and the bar.
• the manufacturing method comprises the step of measuring a radial dimension of the tube and of adjusting the additive manufacturing process according to the radial dimension of the tube . Thanks to the present invention, an amount of material is deposited with a high precision so as to minimize any lack of matching and thus enable an optimal interference.
• the manufacturing method comprises the steps of:
• the step of providing the further coupling stretch is carried out once the annular element has been fixed to the bar.
• Figure 1 is a perspective view of a shaft with annular elements obtained according to the present invention.
• FIG. 2 is a lateral view with parts in cross section of the shaft of Figure 1;
• Figure 3 is a lateral view with parts in cross section according to the line III-III of Figure 2;
• FIG. 4 is a lateral view of one of the annular elements of Figure 1;
• FIG. 5 is a cross-sectional view according to the line of section V-V of Figure 4.
• FIG. 6 is a lateral view with parts in cross section of a portion of the shaft during a step of the manufacturing method
• FIG. 7 is a lateral view with parts in cross section of a portion of the shaft during a step of the manufacturing method and a device used during a step of the manufacturing method;
• FIG. 12 is a lateral view of a detail of an alternative embodiment of the shaft of Figure 1.
• the bar 1 with shaped profile comprises a bar 2 that extends along an axis Al, and a plurality of annular elements 3 fixed on the bar 2.
• the bar 2 has coupling stretches 5 having an external dimension Dl in a radial direction with respect to the axis Al and free stretches 6 having an external dimension D2 in a radial direction with respect to the axis Al that is smaller than the dimension Dl .
• the bar 2 has a greater radial thickness in the coupling stretches 5 than in the free stretches 6.
• the coupling stretches 5 house the annular elements 3 that are fixed to the bar 2 by interference .
• the difference between the dimension Dl and the dimension D2 is comprised between 0.05 mm and 1 mm.
• the bar 2 For each coupling stretch 5, the bar 2 comprises at least one projection 7 set in a radial direction with respect to the axis Al obtained in the respective coupling stretch 5.
• the dimension Dl and the dimension D2 are respective external diameters of the tube 4.
• the bar 2 is obtained by wire drawing of a material, in particular metal material.
• the bar comprises a plurality of tubes aligned along the axis and welded together.
• Each tube is obtained by wire drawing of a preferably metal material.
• the tubes are obtained from a sheared metal plate bent about the axis A of extension of the plate itself.
• the bar 2 is obtained by extrusion of a material, in particular metal.
• the bar has a cylindrical shape and is internally full.
• each projection 7 extends in height so as to be radial to the axis Al .
• the projection 7 entirely occupies the coupling stretch 5, extending in length along the axis Al throughout the coupling stretch 5 and in an annular way about the axis Al throughout the coupling stretch 5 so as to form an annular projection 9.
• the coupling stretch comprises a plurality of projections.
• the plurality of projections entirely occupies the coupling stretch.
• each projection of the plurality of projections is distributed about the axis Al in an annular way, and the projections of the plurality of projections are set at a distance apart from one another within the coupling stretch.
• the projections lie in planes parallel to one another and consequently, the coupling stretch is not occupied entirely by the plurality of projections.
• each projection does not extend annularly about the axis of the bar, and the projections of the plurality of projections are distributed about the axis of the bar so as to define a set of annular projections about the axis of the bar.
• the projection 7 is replaced by the projection 107, which extends along the axis Al and about the axis Al .
• the projection 107 occupies the coupling stretch 5 only partially.
• the projection 7 has a helix shape that develops about the axis Al .
• the annular elements 3 have an axis A2 and have an opening 10 having a dimension D3.
• the opening 10 is circular and the dimension D3 is the diameter D3 of the opening 10.
• the dimension D3 of the annular elements 3 is greater than the dimension D2 of the bar 2.
• the axis A2 and the axis Al coincide.
• annular elements 3 With reference to Figure 1, a certain number of the annular elements 3 is constituted by cams 11 and another number of the annular elements 3 is constituted by rings 12.
• Each opening 10 of each annular element 3 has an annular inner face 13 that develops about the axis A2 and has a plurality of teeth 14.
• Each tooth 14 develops in length parallel to the axis A2 and in height so as to be radial to the axis A2.
• the plurality of teeth 14 is distributed about the axis A2 so as to provide an annular toothing 15 on the inner face 13 of the opening 10.
• the annular elements 3 are fixed to the bar 2 in the coupling stretches 5 at the projection 7, in such a way that the annular toothing 15 of the annular elements 3 and the projection 7 of the bar 2 provide a fixing by interference.
• each annular element is smooth.
• the annular elements are fixed to the bar by interference in the coupling stretches thanks to the projections of the coupling stretches.
• the projections 7 of the bar 2 are obtained by an additive manufacturing process carried out on a bar 2 having a smooth surface and thus define the coupling stretches 5 of the bar 2.
• a processing device that carries out an additive manufacturing process.
• additive manufacturing process is understood an operation through which one or more layers of material are added to a semifinished object to obtain a finished object or to provide a step of production of a finished object.
• the processing device 20 comprises a metal-powder injector 21 and a heat source 22.
• the heat source 22 is a laser beam.
• the processing device 20 provides a process of deposition of material thanks to the powder injector 21, which directs a flow of metal powder 24 onto the bar 2 with smooth surface of Figure 6.
• the powder is fixed to the bar 2 thanks to the heat source 22.
• the processing device 20 comprises a gas injector 23, which injects a flow of gas that develops in an annular way about the flow of metal powder 24 and the heat source 22 in order to isolate the flow of powder 24 and the heat source 22 from the surrounding atmosphere.
• the processing device 20 comprises a rotation unit (not illustrated in the attached figures) coupled to the bar 2 for controlling the angular position of the bar 2 during processing.
• the projection 7 is obtained through the processing device 20.
• the processing device 20 forms each projection 7 by moving parallel to the axis Al and causing the bar to turn about the axis Al .
• the processing device 20 comprises a measuring device 25 for measuring the dimensions of the projection 7 during deposition of the metal powder.
• the processing device 20 adjusts the flow of powder 24 according to the measurement of the dimensions of the projection 7 carried out by the measuring device 25 in real time.
• the processing device 20 forms the projection 107 by moving in a direction parallel to the axis Al and simultaneously causing the bar 2 to turn about the axis Al .
• the measuring device 25 is configured for measuring the dimensions of the bar
• the processing device 20 is configured for adjusting the flow of powder 24 according to the measurement of the dimensions of the bar 2.
• the annular elements 3 are obtained by a forging process.
• the plurality of teeth 14 is obtained, in particular along the inner face 13 of the opening 10 to form the annular toothing 15.
• the plurality of teeth 14 is obtained through a broaching process.
• the annular elements 3 are obtained in such a way that the annular element 3 can be inserted on the bar 2.
• the annular elements 3 are sized in such a way that the internal dimension D3 is greater than the external dimension D2 of the bar 2.
• the annular elements are obtained by a process of sintering of metal powder.
• the annular elements are obtained by an additive manufacturing process.
• the shaft 1 is obtained at least through the following steps:
• the manufacturing method includes forming all the annular elements 3 through steps d) and f) and then implementing in sequence steps b) , c) , and d) for each of the annular elements 3.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
• Heat Treatment Of Articles (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=53900924

Family Applications (1)

Country Status (3)

Families Citing this family (1)

Family Cites Families (4)

• 2015
  • 2015-05-13 IT ITMI2015A000668A patent/ITMI20150668A1/it unknown
• 2016
  • 2016-05-13 EP EP16726184.1A patent/EP3294491A1/en not_active Withdrawn
  • 2016-05-13 WO PCT/IB2016/052789 patent/WO2016181363A1/en unknown

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