Shanghai Jugong Hydraulic Technology Co., Ltd.
Contact: Manager Zhang
Mobile: 13671968158 /13681692048
Tel: 0512-53401911 Fax: 0512-53401911
Zip code: 215400
Address: No. 91 Yinchuan Road, Taicang City, Suzhou, Jiangsu, China
Hydraulic valve block design experience
The design of hydraulic valve blocks is mostly non-standard design. It needs to be designed according to different working conditions and usage requirements. When designing valve blocks, it is roughly divided into the following steps: material selection, processing and heat treatment, deburring and cleaning, surface rust prevention. Treatment, testing. 1. Material selection: Different materials determine different pressure levels. Firstly, according to the pressure of use, the material is selected reasonably. Generally speaking, the following principles are followed: When the working pressure is P<6.3MPa, the hydraulic valve block can be cast iron HT20-40. Cast iron parts can be used for large-volume casting, reducing man-hours and improving efficiency, especially for standardized valve blocks. 6.3MPa≤P<21MPa, the hydraulic valve block can be aluminum alloy forgings, 20# forged steel or Q235; low carbon steel has good welding performance, especially suitable for non-standard hard pipes (many valve blocks need to be welded with hard pipes in use) ) Perform welding. When P≥21MPa, the hydraulic valve block can be selected from 35# forged steel. After forging directly after machining or machining, the quenching and tempering treatment HB200-240 (generally high pressure valve block, often flaw detection, machining and heat treatment cycle). 2. Design and processing of the valve block When the valve block is designed, the initial thickness of the valve block is set to be 5 times of the maximum diameter, and then gradually reduced according to the specific design; when designing the channel, the hole should be arranged reasonably, and the deep hole and the inclined hole should be minimized. Process holes, first arrange large flow passages, and finally pilot oil passages, the safety wall thickness between each tunnel shall not be less than 3 ~ 5mm, and the deflection of the drill bit within the allowable range shall be considered, and the spacing of adjacent tunnels shall be appropriately increased; The flow rate of hydraulic oil in the channel should not be higher than 12m/s, and the oil return channel should be 20-40% larger than the oil inlet channel; the valve block inlet port, working port and control port should be processed with pressure measuring port; For the larger mass of the valve block, there must be a lifting screw port. After the valve block is designed, the machining process is as follows: (1) Pre-processing. The material of the processing valve block needs to ensure the internal structure is dense, there must be no defects such as interlayer and trachoma, and the blank should be inspected before processing. Cast iron blocks and larger steel blocks should be aged and pretreated before processing. (2) Cutting. Generally, at least 2 mm of machining allowance is left on each side. (3) Milling shape. Milling the valve block 6 side, leaving a 0.2-0.4mm coarse grinding amount on each side. (4) Rough grinding. The surface of the coarse grinding valve block is 6 mm, and the grinding amount of 0.05 to 0.08 mm is left on each side to ensure that the parallelism of each pair of corresponding faces is less than 0.03 mm, and the perpendicularity of the two adjacent faces is less than 0.05 mm. (5) Cross stitching. Conditional can be done directly on the CNC drilling machine with a center drill. (6) Drilling. The surface roughness of each hole was Ra12.5. (7) Fine grinding. The valve block 6 was ground and the surfaces were ground to a roughness of Ra 0.4 um. When processing the valve block, the geometrical tolerance must be strictly controlled to meet the requirements. The geometrical tolerance values are as follows: The vertical tolerance of the 6 faces of the valve block is 0.05mm; the parallelism tolerance of the opposite surface is O.03mm; The flatness tolerance of each surface is O.02mm; the perpendicularity tolerance between the thread and its mating surface is 0.05mm; the tolerance of the perpendicularity of all holes to the end surface is 0.05mm 3, deburring and cleaning to ensure the cleaning of the hydraulic system Degree, the valve block must be deburred. At present, many manufacturers still use manual brushing for deburring, but also use methane blasting to deburr. After the deburring of the valve block is completed, an endoscope test is required to ensure that the burr is cleaned up. Finally, the valve block is cleaned. Remove various particulate contaminants, corrosives, grease, etc. attached to the surface of the valve block. 4. Surface anti-rust treatment In order to ensure that the valve block does not rust prematurely during use, it must be rust-proofed. The internal oil passage of the valve block can be acid-washed and phosphatized, and the external surface anti-rust treatment process mainly includes surface treatment such as bluing, cadmium plating, galvanizing, and nickel plating. 5. Pressure-holding test The pressure-holding test of the valve block is carried out according to the design requirements. Different system working pressure, the safety factor of the valve block is not the same: working pressure is less than 16MPa, test pressure is 1.5 times working pressure is less than 25MPa, test pressure is 1.25 times working pressure is less than 31MPa, test pressure is 1.15 times test holding time is 5 to 10 minutes, there must be no leakage at each sealing surface and joints.
Company Address: No. 91 Yinchuan Road, Taicang City, Suzhou City, Jiangsu Province
Postal code: 215400