Application and Maintenance of Hydraulic Valves

First, The Design Principle of Hydraulic Valve
    The design of the hydraulic valve is mainly for the design of the hydraulic valve group, and the hydraulic valve group must first consider the oil circuit before the design, to determine in advance which parts of the oil circuit can be integrated, the design of the oil circuit must be simple, to save unnecessary steps. After determining the oil path, the main thing is the inclined hole and the process hole, these things on the oil path should be reduced, so long as it is enough, not too much, in the design of the inclined hole and the process hole should pay attention to the combination of the aperture and flow, the direction and position must be appropriate, to consider the overall situation, to ensure that the requirements are met. If the direction or position is not appropriate, you need to adjust the component, you must ensure that it can be simple and easy to operate and maintain.
    About the design of hydraulic valve first from the hydraulic valve design size to discuss. The length, width and height of the hydraulic valve group are generally determined by referring to the size of the parts that make up the hydraulic valve group. For example, the height of the hydraulic valve group should be consistent with the height of the components as far as possible without affecting the actual role. The length of the hydraulic valve group, without affecting the layout and structure, is determined by the size of the aperture or length of the screw hole. The width and length of the hydraulic valve bank are roughly the same determinant. Secondly, we introduce the dimensioning, this step is mainly applied in the design of the drawing, to mark the port of some components, aperture, each group size, size and so on. The last is the design of the channel, the most important thing in this design is the layout, the overall arrangement of the system, the classification of the oil circuit, first of all must make the main oil circuit conduction, and then, for small oil circuit or other oil circuit gradually conduction. The channel of these hydraulic valves must be designed to ensure that the length is appropriate, the Angle is relatively small, and the hole of the oil passage is suitable, so as to effectively control the weight, size and volume of the hydraulic valve group, and to make reasonable use of it.

Second, The Application of Hydraulic Valve Group
     According to the current situation, hydraulic valves can be divided into many types according to different situations and different uses of hydraulic valves. This article focuses on one of them. This hydraulic valve group includes four parts, which are two-way cartridge valves composed of cartridge parts, control cover plates, pilot control valves and integrated blocks.
The following describes the main content and functional uses of these four parts. The structure of the cartridge can be considered as a slide valve or a cone valve, and the role of this part of the component is very important to control the flow direction, flow speed and pressure of the oil in the channel or other places. The control cover plate can effectively control the real-time work of the cartridge valve, mainly because there are many pilot control components in its composition, these components can adjust or control the work of the cartridge valve, the control cover plate is basically a bridge, connected to the control valve and the components, and the pilot control valve must also choose to be installed on it. In terms of the current situation in our country, the two-way cartridge valve is relatively common, from the economic perspective, because its components and some necessary pipeline connections are less, it is easy to integrate, so it is very convenient, suitable for large-scale mass production, which can greatly reduce production costs. From the point of view of use, its structure determines that its volume will be small, so it is very convenient, and its control switch speed is very high, so it determines that it is very efficient and reliable when in use. In addition, it can also be controlled with large power, the advantage of this is that the loss of pressure will be reduced, and the loss of heat will be reduced. Finally, the two-way cartridge valve is not affected by reversing. The main function of the two-way cartridge valve is to connect the route of the oil or control it to disconnect.

Three, Hydraulic Valve Maintenance
    With the growth of time, the hydraulic valve will inevitably have some failures, which involves the maintenance of the hydraulic valve. In actual production, the maintenance of hydraulic valves is mainly timely cleaning, the combination and selection of some parts, and the repair of dimensions. There is oil in the channel of the hydraulic valve, and it is easy to precipitate the oil, which will make the hydraulic valve produce some unnecessary failures, so we must clean up in time, remove the hydraulic valve and then clean it, so that the function of the hydraulic valve can be restored in time. When cleaning, pay attention to safety, a lot of sediment is not easy to clean, you need some cleaning liquid, these cleaning liquid will generally be corrosive or toxic, and even some flammable, so you must be careful. The parts after cleaning must be kept well to prevent it from being corroded again. After the cleaning is completed and the hydraulic valve is installed, it can continue to run after being tested. If some parts of the hydraulic valve are damaged, and more serious, in this case, the general choice of recombination. If the hydraulic valve is maintained by specialized experienced personnel, it will greatly increase its life, and its reliability and working performance will be maintained at the original level, even so, we must be vigilant in daily production to prevent accidents.、

Maintenance Method
    In the actual use of hydraulic equipment, due to the influence of various factors, the hydraulic valve may have some failures, which has an adverse impact on the normal use of hydraulic equipment, so through scientific and reasonable methods to repair the hydraulic valve failure, and better solution is an important means to ensure the normal use of hydraulic equipment. As a hydraulic equipment management and maintenance personnel, we should have a detailed understanding of the maintenance methods of hydraulic valves and master them skillfully, so as to effectively deal with the failure of hydraulic valves and ensure the good operation of hydraulic equipment.

1. Clean the Hydraulic Valve
In the process of hydraulic valve maintenance, the hydraulic valve disassembly and cleaning is the first process. In the actual use of hydraulic equipment, due to the hydraulic oil pollution will lead to oil precipitation, or some granular impurities in the hydraulic oil, which will lead to the failure of the hydraulic valve, usually after disassembly and cleaning, these faults can be removed, so that the hydraulic valve can restore its function. For hydraulic valve disassembly and cleaning, it mainly includes the following five aspects:
(1) Disassemble. For the hydraulic valve, although the various parts are mostly connected by bolts, the hydraulic valve is not disassembled in the design, if the lack of special equipment or lack of professional technology and forced disassembly, the result may be damage to the hydraulic valve. Therefore, before disassembly, maintenance personnel should master the hydraulic valve structure, and should master the connection between the various parts, and record the position relationship between different parts during the disassembly process.
(2) Check and clean up. The valve body and valve core and other parts are inspected to observe the dirt deposition, on the basis of not causing damage to the working surface, the use of brush, cotton yarn and non-metal scraper will be concentrated dirt removal.
(3) Rough washing. The valve core and valve body are placed on the tray of the cleaning box, and it is heated and soaked, compressed air is used at the bottom of the cleaning tank, and the residual dirt is cleaned by using the stirring effect of the bubble, and the ultrasonic cleaning is feasible if the conditions permit.
(4) Fine. First, high pressure positioning cleaning with cleaning solution, and then drying with hot air. In the case of enterprise conditions, existing fresheners can be selected, and organic cleaning agents can also be used in some special occasions, such as gasoline and diesel.
(5) Assembly. Assemble according to the hydraulic valve diagram or the assembly relationship of the parts recorded during disassembly, and pay attention to careful operation during assembly to prevent the parts from being damaged. For some of the original sealing materials, it is easy to be damaged during the actual disassembly, so it should be replaced during assembly.

2, Optional Combination Parts Maintenance
    In the process of manufacturing hydraulic valves, most of the selection methods are selected in order to effectively improve the assembly accuracy, that is to say, for a number of processed parts, such as the spool and valve body, should be selected according to the actual size of the most reasonable clearance, and then assembled, so that the spool can ensure good sliding performance and good sealing performance. In other words, for the same type of hydraulic valve, its valve body and valve core may have certain differences in size, in the actual use of the process, when the enterprise has a large number of failed hydraulic valves, all hydraulic valves can be disassembled and cleaned, the inspection and measurement of each part, according to the results of the detection of classified parts, and then use a certain method to re-combine and match. After the inspection, if the valve body and spool are found to be worn, but there is no serious scratch on the working surface or no serious wear in the local area, then the valve body and spool with appropriate clearance can be selected for re-assembly; If the gap between the valve body and the valve is increased compared with the gap specified in the product drawings, and the increase degree is between 20% and 25%, at this time, a certain method should be taken to increase the size of the valve core, and then the research and repair. For the valve seat and the spool between the taper valve groups, if the contact surface in the conical valve is poorly sealed, because the taper valve can automatically compensate the gap under the action of the spring, so as long as the grinding can be carried out. If the valve body and valve wear lack of uniformity or scratches on the working surface, the use of the above method can not make the hydraulic valve function to be better recovered, then the valve body and the spool should be selected to meet the processing allowance requirements in the interference amount, for the valve body hole, should be properly articulated, for the spool should be properly ground, so that the shape accuracy and assembly clearance can be reasonable.

3, Size Restoration Repair
    For the repair and maintenance process, which includes many types, the more suitable and widely used in hydraulic valve maintenance is brush plating maintenance method, which is also called electric plating maintenance. For the electroplating repair repair method, the reasonable repair thickness is within 0.12mm, which can basically meet the maintenance requirements of the uniform wear hydraulic valve, and further processing is still needed after repair. In the electroplating repair and maintenance, the more common process is chemical composite electroplating, the process method is developed on the basis of mature electroplating process, its advantages are convenient operation method, relatively simple equipment, and relatively low cost, while relatively easy to control its reaction, in the hydraulic valve maintenance process, The composite coating with more components can be precipitated on the surface of the valve hole or valve spool by this process, and the coating can be firmly combined with the parent metal, and its mechanical strength is relatively high, the thermal conductivity is also relatively good, and its thermal expansion coefficient is relatively low, the friction coefficient is relatively low, and its self-healing ability is also relatively strong. Therefore, using this method in hydraulic valve maintenance can get a better effect.