A columnar hydraulic tappet and its plunger preparation method

Abstract

The invention discloses a columnar hydraulic tappet, which has a shell, and a plunger which moves axially relative to the shell is correspondingly installed in the inner cavity of the shell, and a first annular groove is arranged under the head of the plunger. There is a second ring groove in the middle of the plunger, the middle wall of the plunger is between the first ring groove and the second ring groove, and the second ring groove is a concave wide ring groove, which is characterized in that the middle wall of the plunger At least one oil inlet hole communicating with the second annular groove is opened on the upper part, and a sealing band is left on the upper part of the middle wall of the plunger for cooperating with the inner cavity of the housing to block the circulation of the hydraulic medium. The position of the plunger oil inlet hole relative to the one-way valve is raised to increase the oil storage capacity of the plunger oil storage chamber. When the engine is cold started, the abundant hydraulic medium can quickly replenish the high-pressure chamber in the one-way valve, shortening the hydraulic pressure. The time it takes for the column to recover from the compressed height to the normal working height, quickly eliminate the valve clearance, reduce the time for the cold start of the valve train to eliminate the noise and the wear of the corresponding parts.

Description

technical field [0001] The invention belongs to the technical field of engine parts manufacturing, and in particular relates to a columnar hydraulic lifter capable of automatically compensating the working clearance of valves. Background technique [0002] The valve mechanism using the roller rocker arm and the hydraulic tappet is widely used in the structure of the overhead cam engine. Compared with the valve mechanism of the mechanical tappet, it has the following advantages: 1) It can compensate the valve clearance in real time and does not require regular manual work. Adjustment; 2) Reduce engine noise and impact; 3) Light weight, smaller friction, and smaller moment of inertia mean less energy loss, which is conducive to improving engine efficiency; 4) The life of parts of the valve train Longer and less maintenance cost. [0003] The columnar hydraulic tappet has a pot-shaped housing, and a plunger that moves axially relative to the housing is fitted in the inner cavi...

AI Technical Summary

Problems solved by technology

[0004] When the engine stops working for a period of time, the hydraulic tappet is pressed at a lower position, and part of the hydraulic medium in the high-pressure chamber is discharged. When the engine starts, the hydraulic medium supplied by the oil pump takes a while to reach the hydraulic tappet. At this time, there is Valve clearance, the plunger of the hydraulic tappet moves upward under the action of the return spring, the high-pressure chamber forms negative pressure, the check valve opens, the hydraulic medium in the oil storage chamber is sucked into the high-pressure chamber, the hydraulic tappet gradually returns to the working height, and the valve The gap is eliminated. If the oil in the oil storage chamber is insufficient, the air will be sucked into the high-pressure chamber, and the support rigidity of the hydraulic tappet will be greatly reduced, causing abnormal noise of the engine, increasing the noise, and accelerating the wear of related parts.

[0005] Chinese patent document CN201228569Y discloses a hydraulic support element. The plunger of this structure is provided with a steering member inside. Its defect is that it cannot be processed at one time when the plunger is formed, and it needs multiple processes to complete, which is time-consuming and laborious; There is a small gap between the inner cavity of the plunger, and the impurities generated during heat treatment and subsequent processing are not easy to clean out

[0007] Chinese patent CN201593451U discloses a hydraulic support element. The plunger of this mechanism adopts the forming process of machining after cold heading. The processing technology is complicated, and the plunger neck and the inner concave ring groove need milling. The metal flow line of the material, the wall thickness of the cutting part is thinner than that of other parts, and the local strength of the structure is weakened. In addition, the volume of the oil storage cavity of the plunger of this structure is small, and the storage capacity of the hydraulic medium is small. In extreme cases, when When the engine starts cold, there may be a risk that the valve clearance cannot be eliminated because there is not enough hydraulic medium to replenish the high-pressure chamber

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