The ferris wheel is one of the common amusement equipment in large amusement parks. In recent years, along with the continuously increasing demand for viewing, the ferris wheel has gradually developed to a height of more than one hundred meters, which puts forward higher requirements for the stability and safety of the ferris wheel drive.
At present, the commonly-used hydraulic drive system of ferris wheel tends to be faster than the rising side when the load is concentrated on the descending side. It usually occurs during the last lap before the ferris wheel being shut down and the first lap after it being started. If the system is not properly adjusted and the load is concentrated, the acceleration sense during descent will be more obvious, which will cause panic among passengers and greatly reduce the comfort of passengers. This phenomenon is related to the eccentric load, especially when the ferris wheel performs the 1/4 eccentric load test.
The system is provided with the hydraulic oil source by the manual variable pump, and the displacement of the pump is set during debugging, which is rarely done under normal operating conditions. The forward and reverse rotation of the ferris wheel can be realized by controlling the electromagnetic reversing valve and the two-way rotation of the driving motor. Besides, the sequence valve and electromagnetic reversing valve are used to realize the stable braking function of the ferris wheel. Among them, the back pressure on the descending side of the ferris wheel can be achieved by adjusting the adjustable throttle valve.
According to the analysis of the orifice flow formula, the flow of the throttle valve is affected by the opening degree and the pressure difference between the front and back of the valve. When the eccentric load of the ferris wheel descends, the force direction of the drive motor changes, and the hydraulic system changes from actively driving the rotation of the ferris wheel to restricting the ferris wheel from stalled descent by back pressure. At this time, the external load is in the same rotation direction as the motor, and the pressure difference between the front and back of the throttle valve increases, resulting in an increase in the passing flow and a faster descent of the ferris wheel. At present, the commonly-used ferris wheel drive system can improve this phenomenon by turning down the throttle valve, however, the impact is that when the ferris wheel rises, the back pressure and the driving pressure will increase, which will result in increased pump noise and heating system as well as other issues.