Hydraulic lifting platform lifting instability factors
Hydraulic lift function diversification, applied in all walks of life, when the hydraulic lift with feeding conditions, so that the electromagnetic coil energized generics clamping arm will smoke box to reach the set value of the pressure relay, the pressure relay issued a signal to raise the smoke box in place, the low-level conveyor part of the duplex shuttle to the hydraulic lift below, the clamping arm down, so that the smoke box to the low-level conveyor, at this time the generics clamping arm up to The highest point, in place, the duplex shuttle car will send the tobacco box to the next level before the conveyor, the high conveyor to the hydraulic lift under the signal from the photoelectric switch, the lifting cylinder will lower the genera to the middle position, waiting for the start of the next cycle.
Hydraulic lift lifting speed instability analysis and countermeasures hydraulic lift put into use, can achieve the basic functional requirements, from the use of the site, often appear cigarette packet slipping, rising position is more difficult to detect to find the neutral, rising with impact noise, hydraulic cylinder oil seepage and other phenomena. The site inspection is mainly lifting hydraulic cylinder lifting speed is too fast, resulting in increased failure rate, seriously affecting the productivity. Lift hydraulic cylinder lifting speed is not stable reason analysis lift hydraulic cylinder lifting speed is not stable, the reasons are many, there are design aspects, there are also processing and manufacturing and use of aspects.
In response to the failure of the hydraulic system, the use of speed stiffness theory, analysis of lifting hydraulic cylinder lifting speed instability causes.
(1) lifting hydraulic circuit composition. Oil pump relief valve, reversing valve, reversing valve, one-way throttle valve (no throttle), lifting cylinder.
(2) the lifting circuit to establish the speed of rigid analysis type. Flow into the hydraulic cylinder, that is, flow through the one-way throttle valve flow rate formula for the flow through the throttle valve; throttle valve throttle port shape and hydraulic oil viscosity and other related coefficients; AT into the throttle port flow area (lifting no throttle); hydraulic pump outlet pressure; P1 for the hydraulic cylinder into the oil chamber pressure, for lifting the hydraulic cylinder plunger area; by the throttle port shape determined by the index, the speed of the speed control circuit can be known as , when the throttle port area is constant, the output speed of the hydraulic cylinder will change with the change of load. And the change of load on the speed of the degree of impact with the speed of rigidity T to express: as the load increases, the lift actuator hydraulic cylinder output speed decreases a negative number; in order to make into a positive number, so the formula plus a negative sign. Substituted into the hydraulic lift, the greater the speed stiffness of the imported throttle speed control circuit into the value, the better the speed stability of the hydraulic circuit.
According to the analysis, the main influencing factors are shown below.
(1) when the load is constant, the smaller the throttle valve mouth into, the higher the system speed stiffness into; conversely, if the throttle valve opening area is larger, the lower into.
(2) When the load is constant, the speed stiffness at low speed is good, when the load changes, the speed stiffness when the load is small is good.
(3)Increase the oil supply pressure to increase the effective area of the hydraulic cylinder, can improve the speed stiffness.
In summary, the main reason for the failure of the hydraulic lift is the hydraulic system lifting speed control circuit design is not reasonable. So whether it is the lift manufacturers or purchase users, must be any check the integrity of the equipment as well as security.