Ratio-variable feedback type digital fluid cylinder

Abstract

The invention relates to a digital fluid cylinder with transformer ratio feedback, belonging to fluid cylinder technology area, especially feedback control technology of self-feedback digital driving hydraulic cylinder. As the piston of fluid cylinder moves in high speed and locates precisely. Feedback bar 7 in fluid cylinder is divided into feedback bar of piston 7-1 and feedback bar of control valve 7-2 and at one end of the feedback bar of piston 7-1 transmission 6 is set. Clutch 13 is set at one end of the feedback bar of controller 7-2 and set at the position where the clutch 13 is joined with the transmission 6. NC device 1 controls the running of driving motor 2 and different clutch terminals 12 of clutch 13 to join and release with the transmission 6. The piston journey is divided into high speed moving segment of long distance and low speed accurate moving segment of micro distance by NC device. In different moving segment different clutch terminal 12 is started so that the core of control valve 14 obtains different feedback energy and different moving speed and located accuracy of piston are controlled.

Description

technical field [0001] The invention belongs to the technical field of fluid cylinders, in particular to the technical field of feedback control of self-feedback digital drive hydraulic cylinders. Background technique [0002] Digital hydraulic cylinder technology fully embodies the characteristics and advantages of digital hydraulic technology. It originated in the 1960s and 1970s. Due to the continuous research and improvement in this field in Germany, Japan and China, digital fluid cylinder technology has gradually reached practical stage. [0003] The existing practical digital cylinder consists of a numerical control device, a stepping motor and a cylinder with a control valve. The function of the control valve is to control the start, stop and direction of motion of the cylinder piston. The basic working principle of the digital hydraulic cylinder is that the microcomputer sends out a control pulse sequence signal, which is amplified to drive the stepping motor to mov...

AI Technical Summary

Problems solved by technology

In the existing digital hydraulic cylinder technology, a single feedback lever is used for control, and there is always a contradiction between motion speed and positioning accuracy. Since the feedback uses a directly connected feedback lever, the feedback speed at the feedback signal collection point and the output point of the feedback signal The speed ratio is only 1:1

That is to say, in the case of constant NC signal frequency, to obtain high speed, it is necessary to increase the pulse equivalent. The most direct way is to increase the helical lead of the piston nut and the feedback screw, and the piston advance speed can be increased. However, this method The positioning accuracy is reduced; similarly, in order to obtain high positioning accuracy, it is necessary to reduce the pulse equivalent. If the screw lead of the piston nut and the feedback screw is reduced, the positioning accuracy requirements are met, but at the same time the digital cylinder Reduced work speed

This contradiction between speed and precision cannot be overcome from the structure itself in the existing scheme, which greatly limits the promotion and use of digital hydraulic cylinders

The existing solution is to use a complex control system, increase the pulse frequency, and increase the movement speed, thereby indirectly compensating for structural defects

Due to the limitation of the direct starting frequency of the stepping motor and the structure of the hydraulic cylinder, the entire control system becomes complicated and the cost increases significantly. It is difficult to achieve the unity of high precision and high speed at the same time. The bottleneck of the industrial application of hydraulic cylinders makes it difficult to obtain widespread promotion

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