Powder metallurgy composite cam sheet and preparation method thereof

Abstract

According to the invention, there are disclosed a power metallurgy composite cam sheet and a fabrication method thereof. The power metallurgy composite cam sheet is constructed by combining a power metallurgy cam be composited on a surface of a matrix. The fabrication method of the power metallurgy composite cam sheet includes sinter welding, braze welding, argon arc welding, laser welding, hot pressing and other methods. The powder metallurgy composite cam sheet fabricated by the invention has merits of stable size, good impact toughness, good abrasion resistance, low cost and so on, so that it can replace an integral cam sheet that is currently fabricated by forging, drawing, power metallurgy or other process. It is suitable for the case where a hollow camshaft is prepared by mechanical assembly, hydraulic forming, welding or other process, so that the usage requirements of an assembled camshaft can be met.

1 - 10 . (canceled) 
     
     
         11 . A power metallurgy composite cam sheet, wherein, the power metallurgy composite cam sheet is constructed by combining a power metallurgy cam on a surface of a matrix, a thickness of the matrix is in a range of 0.1-20 mm, and a thickness of the powder metallurgy cam in the powder metallurgy composite cam sheet is in a range of 0.5-50 mm. 
     
     
         12 . The composite cam sheet according to  claim 11 , wherein, the matrix in the power metallurgy composite cam sheet is a circular tube or a special-shaped tube made of steel, nickel, titanium, copper, or aluminum. 
     
     
         13 . The composite cam sheet according to  claim 11 , wherein, the power metallurgy cam in the power metallurgy composite cam sheet is of an iron-based powder metallurgy material, a titanium-based power metallurgy material, a nickel-based power metallurgy material or a hard alloy. 
     
     
         14 . A fabrication method of a power metallurgy composite cam sheet, comprising the following step: combining a power metallurgy cam on a surface of a matrix so as to form the power metallurgy composite cam sheet. 
     
     
         15 . The fabrication method of the power metallurgy composite cam sheet according to  claim 14 , wherein the step of combining a power metallurgy cam on a surface of a matrix comprises the following steps: fabricating a pressed compact for the powder metallurgy cam by using a conventional powder pressing method, fabricating a blank for the powder metallurgy cam sheet at a temperature is in the range of 600-1500° C. for 10-120 minutes, and then welding the matrix and the powder metallurgy cam together by using braze welding, argon arc welding, or laser welding, wherein, material for a solder may be copper, a copper alloy, nickel, a nickel alloy, aluminum, an aluminum alloy, titanium, or a titanium alloy, and its morphology is powder-shaped, wire-shaped, or piece-shaped, the welding is carried out in an atmosphere of vacuum, hydrogen gas, decomposed ammonia, or other protective atmosphere at a temperature in a range of 600-1200° C. for 10-120 minutes. 
     
     
         16 . The fabrication method of the power metallurgy composite cam sheet according to  claim 14 , wherein the step of combining a power metallurgy cam on a surface of a matrix comprises the following steps: placing a matrix on a core rod, and after powders are filled, pressing the powders into a composite cam sheet pressed compact, next, sinter welding the pressed compact at a temperature is in a range of 600-1500° C. for 10-120 minutes. 
     
     
         17 . The fabrication method of the power metallurgy composite cam sheet according to  claim 14 , wherein the step of combining a power metallurgy cam on a surface of a matrix comprises the following steps: placing matrix powders and cam powders in layers into a mold by way of filling, then pressing the powders into a pressed compact for the composite cam sheet, and lastly, sintering the pressed compact at 600-1500° C. for 10 to 120 minutes. 
     
     
         18 . The fabrication method of the power metallurgy composite cam sheet according to  claim 14 , wherein the step of combining a power metallurgy cam on a surface of a matrix comprises the following steps: placing a matrix on a core rod, and after powders are filled, hot pressing the powders at 600-1400° C. for 10 to 120 minutes. 
     
     
         19 . The fabrication method of the power metallurgy composite cam sheet according to  claim 14 , wherein the step of combining a power metallurgy cam on a surface of a matrix comprises the following steps: placing matrix powders and cam powders in layers into a mold by way of filling, and then hot pressing the powders at 500-1400° C. for 10 to 120 minutes 
     
     
         20 . The fabrication method of the power metallurgy composite cam sheet according to  claim 14 , wherein the step of combining a power metallurgy cam on a surface of a matrix comprises the following steps: fabricating a pressed compact for the powder metallurgy cam by using a conventional powder pressing method, assembling it with the matrix, and then sinter welding the pressed compact assembled with the matrix at a temperature is in a range of 600-1500° C. for 10-120 minutes, the atmosphere for the sinter welding being an atmosphere of hydrogen gas, an atmosphere of decomposed ammonia or vacuum. 
     
     
         21 . The fabrication method of the power metallurgy composite cam sheet according to  claim 14 , wherein, the matrix in the power metallurgy composite cam sheet is a circular tube or a special-shaped tube made of steel, nickel, titanium, copper, or aluminum. 
     
     
         22 . The fabrication method of the power metallurgy composite cam sheet according to  claim 14 , the power metallurgy cam in the power metallurgy composite cam sheet is of an iron-based powder metallurgy material, a titanium-based power metallurgy material, a nickel-based power metallurgy material or a hard alloy. 
     
     
         23 . The fabrication method of the power metallurgy composite cam sheet according to  claim 14 , a thickness of the matrix is in a range of 0.1-20 mm, and a thickness of the powder metallurgy cam in the powder metallurgy composite cam sheet is in a range of 0.5-50 mm.