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Chain wheel for VVT system and preparation method of chain wheel

A sprocket and sprocket tooth technology, which is applied in the field of VVT system sprocket and its preparation, can solve problems such as low production efficiency, oil leakage, and performance impact

Inactive Publication Date: 2018-03-13
江苏智造新材有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the traditional VVT system, the powder metallurgy parts are composed of sprocket, stator, cover plate and rotor. One end face of the stator is closely matched with the assembly surface of the sprocket. If it cannot be tightly matched, the VVT ​​may cause oil leakage during the working process and affect the performance
Traditional VVT system powder metallurgy parts have the disadvantages of many parts, complex assembly relationship between parts, many parameters related to assembly relationship of a single part, difficult quality control, low production efficiency and high cost.

Method used

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  • Chain wheel for VVT system and preparation method of chain wheel
  • Chain wheel for VVT system and preparation method of chain wheel
  • Chain wheel for VVT system and preparation method of chain wheel

Examples

Experimental program
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Effect test

Embodiment 1）

[0027] See figure 1 , figure 2 and image 3 , the sprocket of the VVT ​​system includes the outer sprocket 1 of the flange, the stator 2 composed of the middle part of the flange and the BOSS part. The sprocket is a powder metallurgy product, and its powder metallurgy component (mass percentage) is C: 0.6-0.9%, Cu: 2.25-2.75%, the rest is Fe and unavoidable impurities.

[0028] The sprocket of the VVT ​​system has high precision. The main parameters are: the density of the flange teeth is controlled at 7.05-7.15g / cm3, the overall density is 7.0g / cm3-7.2g / cm3; the hardness of the teeth is 460-650HV5, and the surface hardness of the substrate is HRB70 MIN ;

[0029] The flatness of the upper and lower end surfaces is ≤0.01MM; the parallelism of the upper and lower end surfaces is ≤0.015MM; the perpendicularity of the lower end to the large inner diameter of the center is ≤0.015MM; the coaxiality of the large and small inner diameters of the center is ≤0.05MM.

[0030] (Exam...

Embodiment 2）

[0049] A preparation method for a sprocket of a VVT system, comprising the following steps:

[0050] (1) Mixing: Design raw material composition and mixing, and mix the following raw materials evenly according to mass percentage: C: 0.9%, Cu: 2.25%, and the rest is Fe and unavoidable impurities;

[0051] (2) Forming: Select a 500Ton CNC forming press, put the prepared powder metallurgy raw materials into the mold of the forming machine and press them into shape. The density of the green body is evenly divided, and the density of the teeth of the sprocket flange is controlled at 7.15g / cm3, and the overall density 7.10g / cm3, at the same time the green body is automatically deburred after demoulding;

[0052] (3) Sintering: Put the formed green body into a high-temperature mesh belt furnace for sintering. The green body is preheated for 10 minutes, then kept at 1120°C for 45 minutes, and finally cooled gradually to room temperature under a protective atmosphere. The sintering atm...

Embodiment 3）

[0067] A preparation method for a sprocket of a VVT system, comprising the following steps:

[0068] (1) Mixing: Design raw material composition and mixing, and mix the following raw materials evenly according to mass percentage: C: 0.8%, Cu: 2.50%, and the rest is Fe and unavoidable impurities;

[0069] (2) Forming: Select a 500Ton CNC forming press, put the prepared powder metallurgy raw materials into the mold of the forming machine and press them into shape. The density of the green body is evenly divided, and the density of the teeth of the sprocket flange is controlled at 7.10g / cm3, and the overall density 7.0g / cm3, at the same time the green body is automatically deburred after demoulding;

[0070] (3) Sintering: Put the formed green body into a high-temperature mesh belt furnace for sintering. The green body is preheated for 8 minutes, then kept at 1130°C for 45 minutes, and finally cooled gradually to room temperature under a protective atmosphere. The sintering atmos...

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Abstract

The invention relates to a chain wheel for a VVT system and a preparation method of the chain wheel. The chain wheel for the VVT system comprises a flange outer side chain wheel body, and a stator composed of a flange middle portion and a BOSS part; and according to the chain wheel, the two parts of a traditional VVT stator and a chain wheel body are combined into a whole and are changed into a single part, and the chain wheel is made to meet the using system of the VVT system. A powder metallurgy method is adopted for making the chain wheel, by means of the main process procedures of materialmixing, forming, sintering, finishing, high frequency quenching, quenching crack full inspection, machining and double-face grinding of upper and lower end faces, inspection, warehousing and the like. The made chain wheel finished product meets the design and use requirements, the defects that parts assembled for the VVT system are large number, production management is difficult, the system assembly quality is not stable, and the production cost is high are effectively overcome, and the high precision, high quality and low cost requirements of the VVT system are fundamentally met.

Description

technical field [0001] The invention relates to parts of an automobile engine, in particular to a sprocket used in a VVT system and a preparation method thereof. Background technique [0002] VVT (Variable Valve Timing), a variable valve timing system, adjusts the camshaft rotation angle to make the valve opening and closing time change with the engine speed, so as to improve the charging efficiency and gasoline combustion rate, so as to achieve the purpose of reducing fuel consumption and reducing emissions . In the traditional VVT system, the powder metallurgy parts are composed of sprocket, stator, cover plate and rotor. One end face of the stator is closely matched with the assembly surface of the sprocket. If it cannot be tightly matched, oil leakage may occur during VVT work and affect performance. Traditional VVT system powder metallurgy parts have the disadvantages of many parts, complex assembly relationship between parts, many parameters related to assembly relat...

Claims

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Application Information

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IPC IPC(8): F16H55/30F16H55/06B22F5/08
CPCF16H55/30B22F5/08F16H55/06
Inventor 施昌旭夏敏石小荣刘桦
Owner 江苏智造新材有限公司