Angle Control of a Water Hydraulic Semi-rotary Motor with a Rotary-type Servo Valve for Water Hydraulics

2016 ◽  
Vol 2016 (0) ◽  
pp. J1110104
Author(s):  
Kenji SUZUKI
2009 ◽  
Vol 2 (2) ◽  
pp. 21-26
Author(s):  
Shigeru OSHIMA ◽  
Takuya HIRANO ◽  
Shimpei MIYAKAWA ◽  
Yoshihiro OHBAYASHI

2010 ◽  
Vol 22 (3) ◽  
pp. 333-340 ◽  
Author(s):  
Toshiya Watanabe ◽  
◽  
Tomokazu Inayama ◽  
Takeo Oomichi

A small capacity servo valve was developed for a small size water hydraulic manipulator, focusing the saving energy. The new servo valve optimizes the machines small flow rate use, makes the stroke longer for wideband use, reduces leakage and makes control easier. The test and evaluation of the servo valve was conducted by examining flow rate characteristics, leakage characteristics and responsibility. The flow rate and leak rate of the servo valve shows to be the same as the oil hydraulic servo valve, while the step and frequency response show good controllability for the water hydraulic manipulator.


2019 ◽  
Vol 31 (5) ◽  
pp. 707-714
Author(s):  
Koki Sakakibara ◽  
◽  
Shunya Suzuki ◽  
Kazushi Shibata ◽  
Yuto Sawada ◽  
...  

Reduction of leakage is a major problem in water hydraulic systems. With a servo valve, it is possible to reduce the internal leakage by reducing the clearance between a spool and a sleeve. However, because the clearance is reduced, wear tends to occur easily between the spool and sleeves when the servo valve is driven. As a result, the durability of the servo valve is reduced. Attention is paid to the durability against wear of ceramic materials, and the wear can be suppressed by using ceramics as the materials of the spool and sleeve. Thus, one can check whether the wear between the spool and sleeve can be suppressed, thereby improving the durability of the servo valve.


2000 ◽  
Vol 41 (12) ◽  
pp. 215-222 ◽  
Author(s):  
S. M. Soini ◽  
K. T. Koskinen ◽  
M. Vilenius ◽  
J. A. Puhakka

Water hydraulics uses tap water or demineralised water as a pressure medium and has fewer environmental impacts than oil-using hydraulics. The applicability is restricted by the microbial quality of the medium. The objectives of this study were to determine whether microbes grow in the pressure medium of a water hydraulic system, biofilm is formed on the surfaces and to describe the diversity of bacteria that survive and grow in water hydraulic systems. A pilot-scale water hydraulic system was used in the experiments. The viable counts in the pressure medium increased in three days from 102 to 3 ×104 cfu/ml followed by a gradual decrease towards the steady-state concentration of 6× 1034 cfu/ml. The total cell numbers decreased from 3×105 to 2 ×104 cells/ml during the three weeks of operation indicating attachment onto the system surfaces as biofilms. The biofilm cell densities on collector slide surfaces varied between 7 ×103 and 1.2 ×104 cells/cm2 after 21 days of operation. The phosphatase activity in the pressure medium was in conformity with the numbers of viable bacteria. The enzymatic activities (α- and β- glucosidase, phosphatase, aminopeptidase) varied between 0.4 and 300 nmol/lh. The diversity of bacteria growing in the system was wide and differed from that of tap water.


2000 ◽  
Author(s):  
Matti O. Linjama ◽  
Jyrki O. Tammisto ◽  
Kari T. Koskinen ◽  
Matti J. Vilenius

Abstract The paper tests experimentally the suitability of inexpensive directly operated two-way solenoid valves for water hydraulic applications in the pressure range from 10 to 40 bars. Seven valves are tested and tested matters include the steady-state and dynamic characteristics as well as durability. Results show small delays and the durability of about ten million openings. The weak point of the valves is a small flow capacity but otherwise the valves are well suited for low-pressure water hydraulic applications. This is demonstrated by using them in a simple on/off position control of a water hydraulic cylinder.


Author(s):  
Koki Sakakibara ◽  
Kazushi Shibata ◽  
Shunya Suzuki ◽  
Satoshi Ashizawa ◽  
Takeo Oomichi

Author(s):  
Y S Liu ◽  
D F Wu ◽  
L Long ◽  
S P Cao

Water hydraulics using water as the working media is paid more attention because of its many advantages compared with oil ones. Water hydraulic pump is the key component in the applications of water hydraulics. Compared with the water hydraulic pump with port plate, the one with port valve has stronger anti-pollution ability and is more suitable for the open system where the working media cannot be filtered finely. For this kind of pump, the characteristics of port valve have direct and significant influences on the flow and pressure characteristics of the pump. In this article, the flow and pressure characteristics of different valves were compared experimentally and a disc valve was selected as the port valve. Then the mathematical model of a single-piston pump with port valve was built and the influences of different factors including spring rigidity, working pressure, etc. on the port valve were analysed. At last, a single-piston pump was developed to test the characteristics of the port valve. Based on these researches, some principles that should be abided in the design of the port valve were suggested.


2011 ◽  
Vol 181-182 ◽  
pp. 305-309 ◽  
Author(s):  
Xin Hua Wang ◽  
Jia Qing Chang ◽  
Shu Wen Sun ◽  
Gang Zheng

An analysis has been conducted on the hydraulic bridge of the water hydraulic servo valve with annular clearance between sleeve and spool land as its first hydraulic resistance. Through some formula deductions, the simplified hydraulic bridge is drawn and the relationship between flapper displacement and differential pressure of spool ends, which is demonstrated by the subsequent simulation works, is extracted. By the CFD(computational fluid dynamics) simulation, firstly, the pressure distributions of the flapper face and the fore end face of the nozzle are obtained. Results show that the flapper has an annular area where the existing pressure is negative. Secondly, the relationship between flapper displacement and flow force acting on flapper is also acquired, which is much beneficial to the steady-state and dynamic analysis of the water hydraulic servo valve.


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