Views: 239 Author: Site Editor Publish Time: 2021-07-13 Origin: Site
In addition to hydraulic crimp fittings and crimp hydraulic hose fittings, we also need to understand the hydraulic system as a whole. Today, we will share with you a very detailed summary of the hydraulic valve block design experience.
The shape of the valve block is generally rectangular hexahedron, which should be 35 steel forgings or continuous casting blanks. The maximum side length of the valve block should not be greater than 600mm, and the number of two-way cartridge valve inserts included should not be greater than 8. Of course, brass ball fittings and brass swivel fittings will satisfy customers who use them.
When the hydraulic circuit contains more than 8 plug-ins, it should be broken down into several valve blocks. The valve blocks are connected with bolts. The connecting holes at the joint surfaces are sealed with O-rings to form a whole Valve block group. And the rectangular performance of the connecting bolt should not be less than 12.9.
When designing the main port of the valve block, the flow resistance loss should be minimized and the processing convenience should be considered. The diameter of the main-stage channel is estimated and selected according to formula (1). D represents the diameter of the hole in mm. Q represents the maximum working flow that may flow through the channel, and the unit is L/min. Vmax represents the maximum flow rate of the working fluid allowed by the channel, and the unit is m/s. Generally, for pressure channels, Vmax is not greater than 6m/s. For the oil return channel, Vmax is not greater than 3m/s. The diameter of the hole estimated according to formula (1) should be rounded to the standard diameter value.
The main-stage channel and the plug-in hole are partially through
When the main-stage orifice penetrates through multiple inserts, to reduce the local flow resistance loss at the penetration, it is advisable to adopt the method of eccentric penetration with the insert hole (make the centerline of the main-stage orifice offset from the centerline of the insert hole). Generally, the centerline of the main-stage channel is tangent to the wall of the plug-in hole. At the same time, the hole diameter can be increased, and the increased diameter should not exceed the requirements of GB2877. In order to improve the manufacturability of the deep hole, the design can consider increasing the hole diameter or adopting the method of drilling at both ends.
In the design, it is necessary to avoid setting up complicatedly connected control ports and three-dimensional oblique holes in the valve block body and make full use of the control ports in the control cover plate or use special control port connectors such as pilot control blocks. The diameter of the pilot channel should be consistent with the provisions of GB2877. If the diameter of the pilot channel is reduced due to process requirements, check calculations should be made to confirm that it will not affect the control requirements of the main stage valve.
When it must be inclined, the inclination angle of the orifice should not exceed 35°, and the orifice must be well sealed. For the main-level oblique hole, the major axis size of the oval orifice caused by the oblique hole processing should be marked on the relevant view.
