Structural features of hydraulic manifold block
According to the structure and use of the division, hydraulic manifold block has a bar block, small plate block, cover plate, plywood, valve mounting base plate, pump valve block, logic valve block, stacked valve block, special valve block, collector drain and connecting block and so on a variety of forms. In the actual system, the valve block body, along with various hydraulic valves, pipe fittings, accessories, and other components, makes up the hydraulic manifold block. Install these components on the valve block.
valve body
Valve block body is the key component of the integrated hydraulic system, it is not only the other hydraulic components of the mounting carrier, but also their oil circuit connected to the channel body. We generally use a rectangular shape for the valve block body, and typically use aluminum or malleable cast iron as the material. Distribute the hydraulic valve-related installation holes, oil holes, connecting screw holes, positioning pin holes, as well as public oil holes and connecting holes throughout the valve block body. Ensure that the apertures connect correctly and do not interfere with the process of setting up the holes.
Generally a relatively simple valve block body has at least 40-60 holes, a little more complex on the hundreds of holes, these holes constitute a crisscrossing hole system network. The body of the valve block features various forms of holes, such as light holes, step holes, and threaded holes. These are generally straight holes that are easy to process using ordinary drilling machines and CNC machine tools. We sometimes set oblique holes for special connectivity requirements, but we use them rarely.
hydraulic valve
Mount hydraulic valves, which are generally standard parts including various types such as plate valves, cartridge valves, and stacked valves, onto the body of the valve block using connecting screws. This arrangement achieves the control function of the hydraulic circuit.
pipe fitting
Pipe fittings are used to connect external piping to the valve block. Connect the hydraulic circuit, composed of various valves and valve block bodies, to external piping. This connection will control hydraulic cylinders and other actuators, as well as feed, return, and drain oil.
Other accessories
Includes accessories such as pipe connection flanges, process hole plugs, and oil line seals.
Layout principles for hydraulic manifold block
The outer surface of the body of the valve block is the mounting surface of the valve element, and the interior is the space for the arrangement of the orifices. The six faces of the valve block form a collection of mounting surfaces. Usually the bottom surface is not installed components, but as a superimposed surface with the tank or other valve block. In engineering practice, for reasons of ease of installation and operation, the mounting angle of the hydraulic valve is usually at right angles.
Functions of the six surfaces on a hydraulic manifold block (for reference only):
Top and bottom surfaces
The top and bottom surfaces of the hydraulic valve block are superimposed joint surfaces with a common pressure port P, a common return port O, a leakage port L, and four bolt holes.
Front, back and right sides
Right side face:
Installation of frequently adjusted components, including pressure control valves, such as relief valves, pressure reducing valves, sequence valves, etc.: flow control valves, such as throttle valves, speed regulating valves, etc..
Front:
When installing directional valves, such as electromagnetic directional valves and check valves, consider the following. If you cannot install pressure valves and flow valves on the right side of the face, install them at the front instead. This arrangement allows for easier adjustment.
Rear:
Install non-adjustable components such as directional valve types.
Left side
On the left side, equip an output port for connecting the actuator. Include an external pressure measurement point and other auxiliary ports. These auxiliary ports should include an accumulator oil hole and an oil hole for connecting the backup pressure relay.
The planning of the spatial layout of the hydraulic manifold block is based on the design requirements of the hydraulic system schematic and layout drawings. It also relies on the design experience of the designer. The recurring principles are as follows:
(1) The dimensions of the hydraulic components mounted on the hydraulic manifold block must not interfere with each other.
(2) Consider the geometry of the valve block primarily in terms of the external dimensions of the components mounted on it. Ensure that there is enough assembly space between the components. Ensure that the distance between hydraulic components is greater than 5mm. You can extend the solenoid on the directional valve, the pilot valve on the pressure valve, and the pressure gauge beyond the installation plane of the valve block. This extension helps reduce the block’s volume. However, make sure that the extended parts do not touch other components.
(3) In the layout, you should consider whether the installation direction of the valve body is reasonable. Position the spool horizontally to prevent its self-weight from affecting the valve’s sensitivity. Especially for directional valves, arrange them horizontally.
(4) The shape and positional dimensions of the common oil holes of the valve block should be determined according to the design requirements of the system. While determining the installation parameters of the components on the valve block, you should aim to make the connecting orifices as orthogonal as possible. This approach ensures that they connect directly, reducing the need for unnecessary process holes.
(5) Each element has more than two oil-through holes. These holes connect with other components and the valve block body’s common oil holes. Sometimes, direct connections are not possible. For this reason, you must design the necessary process holes. Valve block hole design involves several considerations. First, determine the number of holes required and decide if you need to increase this number. Next, specify the type of holes and their locations. Finally, define the size, diameter, and depth of the holes on the valve block.
(6) The to small wall thickness between inaccessible orifices must be strength-checked.
(7)Pay attention to ensure that the fixed screw holes for hydraulic components in the valve block do not touch the oil pipeline. Additionally, the small wall thickness should undergo strength calibration.
Based on the above principles, the hydraulic manifold block layout is optimised as follows:
(1) If the number of hydraulic components on a face of the hydraulic manifold block does not exceed four, arrange the hydraulic components near each of the four corners. The components do not need to be placed exactly on the corners. This ensures that the process hole design is carried out near two edges.
(2) If the number of hydraulic elements on one face of a hydraulic manifold block does not exceed eight, arrange the hydraulic elements near each of the four edges. You can also arrange them near each of the four corners. Additionally, you can arrange them near each of the four corners. This approach ensures that you design the process holes near one or two edges.
(3) If the number of hydraulic components on one face of a hydraulic manifold block exceeds eight, consider using intelligent methods for optimal design.
The hydraulic manifold block normally contains no more than a total of 10 hydraulic components. The number of hydraulic components assigned to each face is generally no more than 10. Typically, this number ranges from 3 to 5.
General hydraulic manifold block designs rarely involve a large number of hydraulic component arrangements. You can meet the basic requirements for system design by following the rules outlined in the first two articles.
Design Ideas for Hydraulic Manifold Block
The integrated block unit circuit diagram essentially converts the hydraulic system principle into an equivalent form. This diagram forms the basis for designing block-type integrated hydraulic control devices and also serves as the foundation for designing the integrated block itself. Block drawings should include the corresponding schematic diagram. The schematic diagram should reflect the connectivity of the oil circuit. Additionally, it must mark the specification model of the components used, the name of the oil port, and the diameter of the aperture. This information is essential for designing the hydraulic manifold block.
Before designing a valve block, you should first read through the schematic and then identify which parts of the oil circuit you can integrate. The number of elements included in each block should be moderate. When designing the valve block body, we should consider both the types of components installed on its sides and its external dimensions. We need to ensure that the oil channel between the holes maintains the smallest permissible wall thickness. Additionally, we should aim for a compact structure that is small in size and lightweight.
Hydraulic Manifold Block Design Principles
The first and foremost principle of hydraulic manifold block design is that the oil circuit must conform to the hydraulic system schematic. This ensures that the design aligns with the system’s operational requirements.
Before designing the valve block, determine which parts of the oil circuit you can integrate. The number of components included in each block should be moderate. If there are too many components, the valve block’s volume increases, and it becomes difficult to design and process. If there are too few components, integration becomes meaningless and leads to material waste. Take the JISCO steel mill billet continuous casting machine shear hydraulic system as an example. This hydraulic system uses cartridge valves to control the flow. The action precision requirements are high, and the system operation demands high reliability.
Hydraulic Manifold Block Design Considerations
Hydraulic manifold block design, the oil circuit should be as simple as possible, minimise deep holes, slant holes and process holes. When matching the aperture of the valve block to the flow, pay special attention to the hole-through area. Ensure that this area is sufficient for the required flow. We need to consider the direction and location of the inlet and outlet, making sure they align with the system’s overall layout and pipeline connections. Additionally, consider the installation and operational aspects. Determine whether the components require vertical or horizontal installation. Ensure that the installation meets all requirements.
When adjusting the components, the design should consider the convenience of operation and observation. For example, place relief valves and speed control valves in positions where the adjustment handles are easily accessible. This arrangement ensures that you can operate the components conveniently. This arrangement facilitates convenient operation. Place components and key elements, such as proportional valves and servo valves, in the upper or outer part of the valve block. This placement will facilitate disassembly and reassembly. In addition, the design of the valve block to set up a sufficient number of pressure measurement points for the debugging of the valve block. For the weight of more than 30kg valve block, should be set up to lift the screw hole. However, under the premise of meeting the use requirements, the volume of the valve block should be as small as possible.
Relief valve: To protect the motor, the system completes the pump’s start or stop in the low-pressure area. Therefore, we select a solenoid relief valve and, to meet high-pressure and high-flow work requirements, we choose relief valves with cartridges;
Reversing valve: Its role is to ensure that the hydraulic shear cylinder reverses smoothly and without impact. Additionally, it ensures that the shear operates only when necessary for cutting, thus avoiding false actions.
Counterbalance valve: This valve functions as a differential circuit to achieve translational control. It helps hydraulic shears perform the differential of cylinders during cut-to-length cutting, and it operates while the billet is being sheared;
Unloading valve: To ensure the rapid return of the hydraulic shear, add a normally closed valve to the bypass. This valve operates only when the hydraulic shear returns;
Cartridge Valves: Select cartridge valves for differential control.
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