Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
  • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
  • B22F7/08—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools with one or more parts not made from powder
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/12—Both compacting and sintering
  • B22F3/1208—Containers or coating used therefor
• • 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
• • 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
  • F01L2301/00—Using particular materials
• • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49229—Prime mover or fluid pump making
  • Y10T29/49293—Camshaft making
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/4998—Combined manufacture including applying or shaping of fluent material
  • Y10T29/49982—Coating
  • Y10T29/49984—Coating and casting

Definitions

• the invention relates to a method for producing a tubular camshaft, in particular for an internal combustion engine, in which individual cams are subsequently applied to a prefabricated tubular shaft.
• Camshafts are usually cast solidly; the cams themselves are brought to their nominal size by turning and grinding. In recent years, light and hollow camshafts have been required with regard to multi-valve technology. This favors central lubrication in terms of construction and allows material savings. Recently there have been practical approaches for assembling the camshafts from individual segments. Individual tubular shaft segments are assembled with finished cams to form the overall shaft, or individual cams are attached to a one-piece shaft tube and connected to it by gluing, soldering or mechanically. A large number of methods have been described for connecting a hollow shaft and prefabricated cams and possibly bearing elements.
• cams As a specific method for applying the cams on the shaft u. a. soldering in connection with pipe expansion described above (DE-OS 34 31 361). To increase the clamping effect and to achieve a high-strength solder connection, the cams are serrated on their inner circumferential surface.
• the inventive method is primarily used for the production of metallic camshafts, but is not limited to these versions.
• the use of hard metals, of metal-ceramic or even purely non-metallic materials is conceivable.
• a material A in the form of a comparatively thin layer into the press cover in the area of the cams and then to fill the cam area of the press cover with a powdery material B.
• Material A can, for example, be injected into the mold in a mixture with an adhesive which can be evaporated later, or it can also be introduced in the form of metallic cloths, ie in the form of a mixture of wear-resistant material and elastic, evaporable binder material.
• the main advantage of the present inventive method compared to the known prior art for the production of tubular camshafts using a prefabricated shaft tube lies in the more economical production, in contrast to the prior art, the selection of materials which is practically unrestricted.
• the economic advantage of the inventive method stems from the fact that lost press sleeves can be produced inexpensively using the plastic blow molding process and yet with great dimensional reproducibility and quality consistency.
• "near net shape" cams can be sintered onto the tubular shaft, which are then brought into the ready-to-use state solely by means of a comparatively inexpensive grinding process.
• the production of camshafts according to the invention and further processing until the product is ready for use is more economical than the production by casting and machining and grinding.
• camshafts become more diverse when using the method according to the invention than when manufacturing according to known methods.
• press cover was closed at both ends - clamped onto the ends of the tubular shaft by means of mechanically lockable sleeves, leaving the pipe ends open - and isostatically pressed at 2500 bar in a cold isostatic press using water as the pressure medium.
• the camshaft could be finished economically by grinding alone.
• a prefabricated tubular shaft made of copper or a low-alloy, comparatively ductile and flowable copper alloy is pushed onto a perforated steel tube of high strength to produce the camshaft for the isostatic pressing process.
• Powder of a wear-resistant steel alloy is introduced as cam material into the lost press cover.
• the composite, perforated steel tube and copper shaft is introduced into one of the two openings of the press cover and pushed through it with shaking and powder compaction.
• the inner dimension of the press cover is such that it fits tightly on both ends of the shaft after insertion of the tubular shaft, but in the remaining areas outside the cams a powder-filled space between the tubular shaft and the press cover wall remains.
• the press cover sits on the ends of the non-perforated steel tube which protrude from the copper tube and fits over a sufficient length.
• the ends of the press cover are clamped onto the pipe surface by means of sleeves and introduced into an isostatic press in such a way that the press medium can also penetrate into the pipe end and there act on the tubular shaft made of copper through the perforated steel shaft.
• the powder material is pressed both through the press cover and via a slight expansion of the copper tube.
• the perforated steel tube is pulled out of the copper tube again. This is usually done effortlessly due to the slight expansion of the copper tube during the isostatic pressing process.
• the camshaft freed from the press cover is sintered in accordance with the conditions of Example 1, but at temperatures which are lower by approximately 100 ° C.
• the sintered camshafts are then finished by mechanical grinding.
• This embodiment of the method enables particularly good and elastic connections to be achieved between the prefabricated tubular shaft and the sintered-on material.
• Material tests have shown that flowable copper already penetrates into the pores between the powder grains in a transition zone during the pressing process and this material crosslinking is further reinforced by interdiffusion during the subsequent sintering process. This makes it possible to achieve particularly firm and at the same time elastic connections between the prefabricated tubular shaft and the cam material. Camshafts manufactured in this way showed no tendency to crack.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Composite Materials (AREA)
• Materials Engineering (AREA)
• Gears, Cams (AREA)
• Powder Metallurgy (AREA)
• Valve-Gear Or Valve Arrangements (AREA)
• Manufacturing Of Tubular Articles Or Embedded Moulded Articles (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6364749

Family Applications (1)

Country Status (4)

Cited By (1)

Families Citing this family (7)

Citations (3)

Family Cites Families (15)

• 1988
  • 1988-10-10 DE DE3834401A patent/DE3834401A1/de active Granted
• 1989
  • 1989-10-03 JP JP1258651A patent/JPH02141506A/ja active Pending
  • 1989-10-05 DE DE8989202500T patent/DE58901036D1/de not_active Expired - Lifetime
  • 1989-10-05 EP EP89202500A patent/EP0364028B1/fr not_active Expired - Lifetime
  • 1989-10-06 US US07/418,123 patent/US5016348A/en not_active Expired - Fee Related

Patent Citations (3)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events