Main faults and troubleshooting of CNC Hydraulic manifold Block – electromagnetic directional valve
(1) the electromagnet is energized, the spool does not change direction; Or electromagnet power, spool no longer;
1. CNC Hydraulic manifold block checks whether the power supply voltage of electromagnet meets the requirements of use.
CNC Hydraulic manifold block if the power supply voltage is too low, the electromagnet thrust is insufficient, can not push the valve core normal reversing.
2. The spool is stuck. cnc hydraulic manifold block
CNC Hydraulic manifold block- If all the performance indexes of the solenoid directional valve are qualified, and the above faults occur in service, the main check is whether the service conditions exceed the specified indexes. Such as working pressure, flow through, oil temperature and oil filtration accuracy. Check again if the return spring is broken or stuck. For the electromagnetic directional valve connected by plate, the irregularity of the surface of the installation plate should be checked, and the installation screw is too tight, so as to cause the deformation of the valve body. In addition, the burr and flash of the spool grinding process are squeezed into the radial balance groove and not cleared. In the long-term work, the oil flow is squeezed out of the radial clearance to make the spool stuck. At this time, the spool should be disassembled and carefully cleaned.
3, THE axis of CNC Hydraulic manifold block- electromagnetic directional valve must be installed in the horizontal direction.
If the installation is vertical, the influence of the weight of the spool, armature and other parts will cause the abnormal reversal or reset.
4. CNC Hydraulic manifold block- Electromagnetic directional valve with special oil drain port, the oil drain port is not connected to the oil tank, or the back pressure of the oil drain pipe is too high, which causes the valve core “stuffy” and can not work normally.
(2) Electromagnet burned:
1. CNC hydraulic manifold block- The voltage of power supply is higher than that of electromagnet, which causes overheating of coil.
2. The push rod is too long, and the stroke of the electromagnet is improper, the electromagnet armature can not pull, so that the current is too large, the coil overheating.
CNC Hydraulic manifold block- When the first electromagnet is burned due to other reasons, it is more likely to occur when the user replaces the electromagnet by himself. Because the distance error between the armature and the core of the electromagnet and the installation surface of the valve body is large, the extension length of the push rod compatible with the original electromagnet may not be completely suitable for the replaced electromagnet. If the replacement of the electromagnet installation distance is shorter than the original, and the valve assembly, because the push rod is too long, it is possible to make the armature can not pull, and produce noise, jitter and even burned.
If the installation distance of the replacement electromagnet is longer than the original, then after assembly with the valve, because the push rod is short, when working, the reversing stroke of the spool is smaller than the prescribed stroke, the opening of the valve is also smaller, so that the pressure loss increases, the oil is easy to heat, and even affect the speed of the actuator. Therefore, when the user replaces the electromagnet, the extension length of the bar must be carefully measured with whether the electromagnet is suitable, and can not be replaced at will.
CNC hydraulic manifold block- The above causes of burning of electromagnet mainly occur in alternating type electromagnet, dc electromagnet is generally not burned due to failure.
3, the commutation frequency is too high, the coil overheating.
(3) dry type electromagnetic directional valve push rod outside leakage oil:
1, CNC Hydraulic manifold block- general solenoid valve at both ends of the oil cavity is the oil discharge cavity or oil return cavity, should check whether the pressure of the cavity is too high. If the discharge or return lines of multiple solenoid valves are strung together in a system and cause excessive back pressure, they should be separately connected back to the tank.
2. The dynamic seal “O” seal ring at the push rod is too worn and should be replaced.
(4) Oil seepage at the joint of the plate connecting the electromagnetic directional valve and the bottom plate:
1, the surface of the installation base plate should be grinding, the finish should be up to ▽7, at the same time, there should be roughness error requirements, and not raised.
2. The mounting screw is too loose.
3, screw material does not meet the requirements, the strength is not enough. At present, many plate connection solenoid directional valve mounting screws are alloy steel screws. If the original screw is broken or lost, replace the general carbon steel screw at will, due to the effect of oil pressure caused by tensile deformation, resulting in leakage of the joint surface.
4. The “O” seal ring on the bottom surface of the electromagnetic reversing valve deteriorates and does not serve as a seal. It should be replaced.
(5) wet type electromagnet suction release too late:
There is a sealing screw at the back end of the electromagnet, and there is air in the back cavity when the first installation is done. When the oil enters the armature cavity, if the air in the back cavity cannot be released, it will be compressed and form damping, making the movement slow. In the first use, unscrew the sealing screw, release air, when the oil is full, then tighten the seal.
(6) CNC Hydraulic manifold block- After long-term use, the motion speed of the actuator becomes slow:
Push rod because of long-term impact, wear shorter, or the armature and push rod contact wear, so that the valve core reverse stroke is insufficient, resulting in smaller oil cavity opening, through the flow is reduced. The push rod or electromagnet should be replaced.
(7) CNC hydraulic manifold block- oil flow actual communication direction does not conform to the direction of graphical symbols:
This is a very likely problem in use. The country issued by the relevant departments to formulate the standard of graphic symbol, hydraulic components, however, many products because of its special structure, the actual path and is does not conform to the standard of graphic symbol, as shown in figure 2-3-80, said two of the single electromagnet spring return type electromagnetic directional valve spool hydraulic graphic symbol, slide valve function of type I1, electromagnet symbols painting on the right side, The path form of the initial position is P→A; B – > O; When the electromagnet is electrified, it is P→B; A – O.
Solenoid reversing valve
CNC Hydraulic manifold block- But in fact, this structure of the electromagnetic directional valve according to the drawing method of the design drawing, the electromagnet is installed on the left. There are two kinds of path types due to different spool structures. One is as shown in the figure, and the other is just the opposite, that is, p-B communication and A→O communication at the initial position; When the electromagnet is electrified, P→A communication, B→O communication, as shown in Figure 2-3-81.
CNC Hydraulic manifold block- Therefore, when designing or installing the oil circuit system of solenoid valve, it can not only follow the standard hydraulic graphic symbol, but should be decided according to the actual path of the product. If the error has been caused, then, for the three – position valve can be replaced by the electrical line solution. For two position valve, the electromagnet and related parts can be turned to install the method to solve. If still unable to correct, have to replace the pipe position, or use the method of increasing the transition path plate to make up. In short, we should know that the standard hydraulic graphic symbol, only represents a type of valve code, does not represent a specific valve structure. The system shall be designed and installed according to the product samples provided by each manufacturer.
This situation is completely similar to the following electro-hydraulic reversing valve, hydraulic reversing valve and manual reversing valve. Because the caliber of this kind of valve is generally larger, the pipeline is thicker, once the error occurs, it is very difficult to change, in the design and installation must be paid attention to.
The inlet and outlet oil cavities of CNC hydraulic manifold block- electromagnetic directional valve are interchangeable as long as they are high pressure cavities. The path form after replacement depends on the specific situation. But the oil chamber and the high pressure chamber cannot be replaced. In the solenoid valve with a special drainage cavity structure, if the oil return back of the garden oil cavity is lower than the allowable back pressure of the drainage cavity, the oil return cavity and the drainage cavity can be connected together to return to the oil tank. Otherwise, all should be connected to the tank separately.