JP2002201917A - Manufacturing method of hydraulic lash adjuster of engine for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an HLA manufacturing method of an engine for a vehicle. SOLUTION: This HLA manufacturing method of the engine for the vehicle can improve familiarity of the engine at an initial time by applying etching treatment further on an HLA upper face on which high carbon carburizing treatment is applied, reduce friction of a valve drain system by about 30% by polishing effect, and improve fuel consumption of the vehicle by about 2 to 3%. This HLA manufacturing method comprises a step S22 for drawing a raw material such as steel for high carbon carburization to a proper diameter, a step S24 for cold-honing the drawn raw material, a step S26 for increasing the wear resistance by applying high carbon carburizing treatment after the cold-honing step, a step S28 for finishing a carburized face through finishing work, and a step S30 for applying etching treatment on the finished surface by NITAL for a predetermined period of time for completion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hydraulic lash adjuster for a vehicle engine, and more particularly to a method for etching an upper surface of a high-carbon carburized hydraulic lash adjuster by further etching the upper surface of the hydraulic lash adjuster. The present invention relates to a method of manufacturing a hydraulic lash adjuster for a vehicle engine, which can reduce friction of a valve drain system by about 30% by an upper surface polishing effect.

[0002]

2. Description of the Related Art In a vehicle engine, a valve lifter is actuated by a cam of a camshaft, and converts the rotational motion of the cam into a reciprocating motion to be transmitted to a valve directly or through a rocker arm of a push rod. In such a valve lifter, a hydraulic lash adjuster (Hydr) is required to operate the valve lifter without a valve gap regardless of the operating temperature of the engine.
aulic LashAdjuster; hereinafter, HLA
). FIG. 1 shows the structure of the HLA. The HLA includes a tappet body 10 that comes into frictional contact with a cam 19 of a camshaft 18. Inside the tappet body 10, a tappet piston, a ball valve, a gap compensation spring, and the like are provided. The tappet body 10 is pressurized upward by a spring 16 attached to the valve 14 to prevent the occurrence of a valve gap while always maintaining a state of contact with the cam 19.

Next, FIG. 2 shows a process of manufacturing an HLA as a tappet body according to a conventional manufacturing method. In the conventional production method, first, if the steel for carburizing (SC
After selecting a carbon steel such as M415H and fixing it to a drawing machine (step S10), it is drawn to have an appropriate diameter (step S12). The drawn material is
After the cold honing process (Step S14), the carburizing heat treatment is performed (Step S16). After the carburizing heat treatment, a finishing process is performed as a finishing process (step S1).
8) Complete the HLA product.

[0004]

In the case of the HLA manufactured by the conventional manufacturing method having such a configuration, there is no problem in the abrasion resistance. In addition, the friction torque increases, causing an increase in the friction of the valve drain system, and as a result, the fuel efficiency of the vehicle is reduced. Also, unlike the mechanical tappet, the HLA is controlled by the hydraulic pressure, so that the surface pressure is not high at the time of contact with the cam.

[0005] In order to solve the above problems, the present invention provides a high carbon carburized HLA upper surface through a drawing and a cold honing process, and further performs an etching process on the upper surface of the HLA to improve the familiarity of the initial engine and the polishing effect on the upper surface. It is an object of the present invention to provide a method of manufacturing an HLA for a vehicle engine, which can reduce the friction of the valve drain system by about 30% and thereby improve the fuel efficiency of the vehicle by about 2 to 3%.

[0006]

According to the present invention, there is provided a method of manufacturing an HLA for a vehicle engine, comprising the steps of: drawing a material such as high carbon carburizing steel to an appropriate diameter; Cold honing the material
A step of increasing abrasion resistance by high carbon carburizing after a cold honing step, a step of finishing a carburized surface through finishing, and a step of subjecting the finished surface to NITAL for a predetermined time. And completing the etching process.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method of manufacturing an HLA for a vehicle engine according to a preferred embodiment of the present invention will be described in detail with reference to FIG. The HLA components described in FIG. 1 are referred to by the same reference numerals.

FIG. 3 is a flowchart showing an HLA manufacturing process according to the manufacturing method of the present invention. As shown here, the preferred embodiment of the present invention illustrates a method of further performing an etching process after finishing a high carbon carburized HLA.

That is, after a material such as high carbon carburizing steel is fixed to a drawing machine (step S20), it is drawn to an appropriate diameter (step S22). Next, the drawn material is cold-honed (step S24), and the cold-honed material is subjected to a high carbon carburizing treatment to increase wear resistance (step S26). The carburized surface of the HLA thus produced is finished (step S28).

The above steps (S20 to S28) were performed by the applicant of the present invention on December 2, 1998 and July 5, 2000.
Published Korean Patent Publication No. 2000-003773
No. 2 discloses it in detail. This patent discloses a high carbon carburizing heat treatment method for improving the pitting resistance, abrasion resistance and frictional resistance properties of a steel. A at the temperature of
Starting carburizing under an atmosphere exceeding the carbon concentration on the cm line and raising the temperature to austenite, high carbon carburizing to form fine carbides in the carburized layer, thereby reducing the pitting resistance of steel. A high carbon carburizing heat treatment method for improving abrasion resistance and friction resistance characteristics has been disclosed.

Such a high carbon carburizing heat treatment method is a heat treatment method applicable to parts such as a mechanical tappet core for an automobile engine, a valve lifter, a connexing rod, a bearing, a drive shaft, and a high load gear. .

After the high carbon carburizing process, the finished surface is etched with Nital for a predetermined time (about 50 seconds) to complete the surface (step S30). The method of etching with NITAL is described in detail in US Pat. No. 5,972,128, issued Oct. 26, 1999. This patent discloses a method of etching cast iron and piston rings in detail, and FIG. 2 shows an enlarged photograph of a cast iron structure etched by NITAL. FIG. 1 shows an enlarged photograph of a cast iron structure that has not been etched.

[0013] The experimental results themselves show that in the case of a vehicle equipped with HLA that has been carburized and etched after high-carbon carburization, the actual traveling range is 2,500 to 3,000 rpm, which is about a fraction of the conventional carburized HLA. It was confirmed that there was a 30% friction reduction effect. This is almost equivalent to a titanium nitride (TIN) coating. In the fuel economy test, the same fuel economy improvement effect as the upper surface of the tapered core was confirmed.

Further, the friction reducing effect of HLA that has not been etched after high carbon carburization is slightly different from that of existing carburizing. This is because the polishing of the upper surface of the HLA was not performed at all, and it was clear that there was no friction reducing effect.

The HLA that has been etched after high carbon carburization has a friction torque before break-in of about 10% as compared with that of titanium nitride (TIN).
Titanium nitride (TI) with 3 hours break-in
Friction torque data similar to the N) system was obtained. Also, 8
After 00 rpm / 10 h and 3000 rpm / 10 h, a constant friction torque value was shown.

In conclusion, in the case of the HLA of the present invention which has been subjected to the etching treatment to reduce the friction of the high carbon carburized material, the effect of reducing the friction and the effect of increasing the fuel consumption of the vehicle can be obtained. Seconds to 1
00 seconds).

[0017]

According to the present invention described above, the high-carbon carburized HLA upper surface is further etched to improve the familiarity of the initial engine, and the upper surface polishing effect reduces the friction of the valve drain system by about 30%. There is an advantage that the fuel efficiency of the vehicle can be improved by about 2 to 3%.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating an HLA structure of a general vehicle engine.

FIG. 2 is a flowchart showing an HLA manufacturing process according to a conventional manufacturing method.

FIG. 3 is a flowchart showing an HLA manufacturing process according to the manufacturing method of the present invention.

[Explanation of symbols]

 10 Tappet body 14 Valve 18 Camshaft 19 Cam

Claims (2)

[Claims] 1. A step S22 of drawing a material such as high carbon carburizing steel to an appropriate diameter, and a step S24 of cold honing the drawn material.
A step S26 of increasing the wear resistance by a high carbon carburizing treatment after the cold honing step; a step S28 of finishing the carburized surface through finishing; (NIT
AL: an etching solution co
nsisting of alcohol and n
A method for manufacturing a hydraulic lash adjuster for a vehicle engine, comprising a step S30 of completing the etching process by itic acid). 2. The finishing surface is treated for about 50 seconds with NITAL (an etching solution).
ion consistent of alcohol
2. The method for manufacturing a hydraulic lash adjuster for a vehicle engine according to claim 1, wherein the etching process is performed by an etching process (and and acid).