First, the VPR pneumatic valve works Input signal increases, the bellows expansion to promote the baffle (ie, lever) * near the nozzle end. When the clearance is reduced, the back pressure of the nozzle is increased and the valve core is pushed down by the diaphragm of the relay. The air inlet opens a large exhaust port to close the output pressure increases, so the actuator push rod to move down to make the valve spool open or closed. As the spool rotates, the cam also rotates and the feedback spring is pulled by the cam follower so that the baffle tends to leave the nozzle until the torque generated by the bellows is balanced with the feedback spring moment. As a result of this torque balance, to ensure that the valve opening and input signals corresponding relationship between the accurate, to achieve the correct spool positioning. Second, the VPR pneumatic valve fault types and causes a positioner no output pressure Failure reasons: 1, no signal pressure, â‘ pneumatic regulator failure; â‘¡ large number of signal line leak. 2, a large number of bellows leak, repair solder or replacement 3, no gas pressure or gas supply pressure is too low. 4, plug the throttle orifice, use less than 0.2mm diameter wire to clear. 5, Locator zero position is not properly adjusted, that is, the gap between baffle and nozzle is too big. Use tools to readjust. 6, the cam installation location is wrong. Because a cam contains air-open and air-off, respectively, and other percentages; open air and gas-off linear features, with four mounting holes, easy to install the wrong. 7, the baffle and the nozzle face is not vertical, the baffle and the nozzle face contact is still a lot of exhaust. 8, Nozzle hole end face pit, need to be replaced. Burr on the end surface, re-ground. 9, Nozzle and base adhesive leaks. Fault signal to reduce the second, the output pressure does not reduce the cause of the malfunction: 1, zero position adjustment is not appropriate, that nozzle gap is too small. 2, the relay diaphragm at the throttle aperture is too small or blocked, the use of 0.3mm wire to clear. 3, the bypass mechanism switch position error, the switch should be located in the "ON" position. 4, the deviation spring is too hard or wrong choice, supply pressure 0.22MPa wire diameter of 1.3mm, 0.28 ~ 0.5MPa when the spring wire diameter of 1.4mm. 5, the cam installation location is wrong. Failure of three gas, no signal, the control valve has completed most of the trip failure reasons: 1, the relay valve seat and the valve core SR2.3 out of contact or poor seal. 2, in the initial position, baffle and the nozzle face has been in close contact. Fault four basic error (linear) failed Failure reasons: 1, feedback spring force or zero adjustment spring force is not properly adjusted. 2, the wrong position of the cam or the installation of the wrong travel pointer. 3, the relay valve seat and valve seat Verne unsealed. 4, the bellows stiffness is too low, the design requirements of 4.9N / mm. 5, the output pipe or actuator leak. 6, adjust the packing compression is too large. Fault adjustment error between the initial point of large failure reasons: 1, cam follower sleeve and the cam is not in contact. 2, the feedback spring selection error, the standard stroke of the spring wire diameter of 0.8mm, 0.7mm split signal. Failure six locator back to the poor (worse) failure reasons: 1, zero position or stroke adjustment is not proper. 2, the arm assembly fasteners loose. 3, zero position adjustment is not tighten the locking screw. 4, bellows poor flexibility, positive and negative displacement of the amount of slight differences. 5, cam follower bushing hole and cylindrical coaxiality beyond the design requirements. 6, the relay deviation spring poor parallelism between the two ends. 7, shaft and bearing radial or axial clearance is too large. 8, the gas pressure instability. 9, bushings and camshaft radial or axial gap. 10, the feedback spring has not been set to deal with.
Solid Collar Needle Roller Bearings
The solid collar needle roller bearing has compactstructure, small radial size and large load carrying capacity. It is suitable for the parts of which the radialoverall size is limited. It is also wide applied to thesituation where the shaft or housing has the swinging motion.In general, the needle roller bearing only withstands theradial load, not the axial load. When the shaft has axial load, itcan be used in combination with other bearings.However, it does not limit the axial shift of shaft or housing.The limiting rotational speed of needle roller bearing is lower.In high rotational speed of main machine, the needle rollerbearing with cage shall be chosen as far as possible.In compassion with other types of Needle Roller Bearings, under the situation of same radial size, the needle roller bearing has the large load carrying capacity and high rigidity but has highfriction torque.This kind of bearing has many series with different structure
and size. It is requested that the hardness, processing accuracy and surface roughness of shaft journal surface and
rolling surface of outer housing be same as those of the collarof bearing. As for the needle roller with G2 class, the diameter varies within 2μm in group. Except the full complement needle Roller Bearings, they have the rigid cages, which can correctly guide the parallel axis line of needle roller.
Solid Collar Needle Roller Bearings,Solid Collar Roller Bearings,High Load Solid Collar Roller Bearings,Inner Ring Solid Collar Roller Bearings
Ningbo Ritbearing Imp & Exp Co.,Ltd. , https://www.nbbearing.de
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