Hydraulic Directional Valve


With the prolongation of the use time of the control valve, some failures or failures are inevitable. At present, various hydraulic directional valve widely used in hydraulic systems all have the phenomenon of valve core clamping, including hydraulic clamping and mechanical clamping. Because the hydraulic clamping of the valve has commonalities, not only the hydraulic reversing valve, but also other hydraulic valves exist, so the manufacturing accuracy of the valve core and valve hole should be strictly controlled. In order to solve the hydraulic clamping, Hanjiu Technology Co., Ltd. adopts the The method of processing several balance grooves on the outer working surface of the valve core has a very good effect. For mechanical clamping, Hanjiu has also formulated some corresponding technical specifications to limit the main influencing factors such as its fitting clearance and eccentricity.


Hydraulic clamping mainly refers to the unbalanced pressure of the diameter caused by the geometrical error and coaxiality error of the spool valve pair, that is, the liquid passes through the eccentric annular conical gap under high pressure, and the gap gradually expands along the liquid flow direction. , then the so-called hydraulic clamping phenomenon will occur. Because the probability of this kind of product manufacturing problem in Hanjiu Technology's products is almost zero, we will focus on the problem of mechanical clamping.


Mechanical clamping generally has the following reasons:

1. The contaminants in the hydraulic oil (such as sand, iron filings, and varnish) are wedged into the gap between the valve core and the valve hole to make it clamped tightly.

2. The gap between the valve core and the valve hole is too small to cause clamping.

3. For the manual reversing valve, due to its structure, the valve core and valve hole are long, so there is a straightness error. In addition, due to the existence of residual stress, sometimes the valve core will be bent during use. In severe cases, a large contact pressure will be generated between the valve core and the valve hole, and friction will be generated when the valve core moves, causing the valve core movement to be blocked, resulting in mechanical jam. At the same time, due to the deflection of some shoulders due to bending, these offset shoulders are prone to hydraulic clamping under the action of high pressure oil.

4. For the combined multi-way directional valve, due to the flatness error of the joint surface, or the convex bump on the joint surface, and the excessive pre-tightening force of the combined bolt, it is easy to cause the valve hole to deform and cause the clamping. .

5. Whether it is a combined or integral multi-way reversing valve, there are positioning parts such as upper and lower covers or positioning sleeves. Due to the eccentricity of these components, it is also easy to cause the offset of the valve core, resulting in blockage of movement and clamping.


Because of the above situation, Hanjiu Technology recommends that you: carefully remove the burrs on the shoulders of the core and the edge of the valve hole undercutting groove, carefully remove the oxide skin of the heat-treated parts, and use the station equipment to prevent Parts bump; prevent parts from bumping during the assembly process, pay attention to cleanliness, and the pre-tightening force of each bolt should be appropriate to prevent valve hole deformation; ensure the cleanliness of the hydraulic system and prevent the oil from being polluted. If you want to learn more about hydraulic systems, or buy high-quality and inexpensive products from Hanjiu Technology, please visit www.hjhydraulic.com, they will serve you attentively.


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