Horizontal two-degree-of-freedom vibration isolating mechanism

Abstract

The invention provides a horizontal two-degree-of-freedom vibration isolating mechanism. The horizontal two-degree of freedom vibration isolating mechanism comprises a connecting plate, wherein a piston rod is inserted in the center of the connecting plate; and four magnetic suspension units are evenly arranged along the circumference of a disc. By utilizing the characteristics of generating the positive rigidity due to like pole repulsion of magnets (comprising electromagnets and permanent magnets) and the negative rigidity due to unlike pole attraction of magnets, the magnetic suspension units are designed to be a horizontal two-degree-of-freedom vibration isolating system with the positive rigidity and the negative rigidity in parallel. Because the positive rigidity and the negative rigidity are in parallel, the positive rigidity and the negative rigidity offset each other, so the horizontal two-degree of freedom vibration isolating mechanism has the self-rigidity close to zero, and the ultra-low frequency horizontal vibration isolation is realized.

Description

technical field [0001] The invention relates to the field of active vibration reduction in semiconductor manufacturing, in particular to a horizontal two-degree-of-freedom vibration isolation mechanism, which can actively suppress the vibration of a workpiece to be processed in the horizontal two-dimensional direction. Background technique [0002] U.S. Patent No. 7,290,642 uses the principle of magnetic levitation to design a positive and negative stiffness parallel device for vertical vibration isolation. Negative stiffness means that when the particle deviates from the equilibrium position, the force it receives is in the same direction as the displacement that occurs, and there is a tendency to continue to deviate from the equilibrium position. The positive stiffness means that when the particle deviates from the equilibrium position, the force it receives is opposite to the direction of the displacement, and there is a tendency to return to the equilibrium position. Thi...

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Problems solved by technology

However, this device sacrifices the pendulum length in order to obtain low horizontal stiffness, and the large pendulum length will lead to a larger volume of the air spring piston in the active damping device, so that the volume of the additional air chamber will be reduced under the condition of a certain volume of the whole device. restricted, which in turn negatively affects its vertical stiffness

In addition, it is difficult to obtain an ideal level of ultra-low stiffness even if the pendulum length is increased by using only the positive stiffness mechanism - the yaw

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