JPS61131841A - Table system - Google Patents

Abstract

PURPOSE:To make such a highly accurate positioning as being below 0.1mum performable in a stable manner without producing overload in a driving mechanism, by checking a vibration to be generated in time of a sudden table stop in a way of making full use of damping action inherent in an overcurrent. CONSTITUTION:A guide mechanism 4 is installed on a base plate 1 and provided with a table 2, while it pivotally supports this table 2 free of slide motion in an arrow 3 direction. And, a damping mechanism 6 checks a vibration to be produced in time of an end of travel in the table 2 by a driving mechanism 5. In addition, a control part outputs a control signal to the driving mechanism 5 and performs the positioning of the table. Therefore, since damping action inherent in an overcurrent is utilized, the vibration generated when the table 2 is suddenly stopped are almost nearly checked. In addition, since the table 2 and a magnet 23 both are of noncontact with the guide mechanism 4, no friction occurs there so that in cooperation with this fact, the positioning of the table 2 takes place at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a table device capable of highly accurate positioning.

[Technical background of the invention and its problems]

Table devices that require ultra-precise positioning have conventionally used hydrostatic fluid bearings (using oil or air) as guide mechanisms. However, when oil is used, it tends to be viscous and provides resistance to external forces, but the oil leaks and spreads, which limits the environment and purpose of use. In addition, in the case of air, there is almost no resistance, so when an external force is applied, a component in the moving direction of the sample stage is applied to the drive device, causing a slight deformation of the drive section, making it difficult to keep it stopped at the target position. In addition, since the kinetic energy of the table is absorbed by the threaded portion and the motor from the moving state to the stop, repeated rapid stops caused severe deterioration of the threaded portion. Furthermore, when rolling elements are used in the bearings of the guide mechanism, although there is a damping effect to some extent, wear on the bearings is unavoidable, and accuracy maintenance and management is not satisfactory. In addition, since the guide mechanism using rolling elements and bevel bearings has frictional force, overrun occurs when attempting to stop the vehicle at a target with high precision.

Positioning becomes difficult.

[Purpose of invention]

The present invention has been made in consideration of the above circumstances.

It is an object of the present invention to provide a table device that can stably perform high-precision positioning of 0.1 μm or less without overloading a drive mechanism.

[Summary of the invention]

This system utilizes the distribution effect of eddy currents to suppress vibrations that occur when the table suddenly stops.

[Embodiments of the invention]

An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the table device of this embodiment. This table device includes a base (1), a table (2) provided on the base (1), and a table (2).
) is slidably pivoted in the direction of arrow (3).
), a drive mechanism (5) that drives the table (2) forward and backward in the direction of the arrow (3), and a vibration damping mechanism that suppresses vibrations generated when the table (2) is finished moving due to the drive mechanism (5) K. (6), and a drive mechanism (control unit (not shown) that outputs a 51K control signal to perform positioning.The guide mechanism (4) has a rectangular cross section. A rectangular parallelepiped table (2) with a hole, a plate-shaped guide (7) on which this table (2) is installed, and a base (1).
A pair of L-shaped supports (81, (9)) are fixed to the guide body (7) and support both ends of the guide body (7), and a pair of L-shaped supports (81, (9)) are installed apart from the base (1) and are guided through the introduction hole a1. It consists of an air supply device (not shown) that supplies air into the hollow part (11) (see Figure 2) provided inside the guide body (both upper and lower surfaces of the force and both sides of the guide body). As shown in Fig. 2, air supply holes (1) are open, and air is supplied from these air supply holes α to the gap between the guide body (7) and the table (2). To do this, move the table (2) to the arrow (
3) It is designed to be supported by static pressure so as to be able to slide freely in the direction.

On the other hand, the drive mechanism (5) consists of a bearing (13) fixed to the base (1), a nut plate a4 protruding from one side of the table (2), and one end screwed into the nut plate a4. At the same time, the other end is attached to the feed screw (13) supported by the bearing (13), the L-shaped support (11), and the bearing (base (1) K fixed close to I3) It consists of a rotating shaft (17) provided coaxially with the screw α (17), a K-shaft joint (feeding via IgJ), and a stepping motor α-Y that rotates the screw α9 in the forward and reverse directions. By rotating the rotation axis αη in the forward and reverse directions, the table (2) supported by static pressure is moved forward and backward in the direction of the arrow (3) via the nut plate I screwed onto the feed screw (15). Furthermore, the allocation mechanism (6) is adapted to drive the table (2).
A U-shaped conductor plate made of aluminum (AJ-), copper (Cu), etc. protrudes along the longitudinal direction from the other side of the A magnet (c) having a pair of magnetic poles (2I), (a) and positioned so that a conductor plate (a) is sandwiched between these magnetic poles a1) and a without contact, and a base (1). ) and a support (goods) that supports a magnet (c). The main surface of the conductor plate is provided parallel to the base (1). Also, the gap between the conductor plate (to) and the magnetic pole Qυ, (2) is
) is set so that there will always be a constant gap even if it moves forward or backward.

In the table device having the above configuration, air supplied from the mass air supply device is passed from the guide body (the force hollow part a1) to the table (2) and the guide body (7) via the air supply hole (I...). ) to statically support the table (2).Then, the stepping motor (I9) is activated based on the control signal from the control unit.As a result, the table (2) moves in the direction of the arrow (3). Then, when the table (2) reaches the target position, the output of the control signal from the control section is stopped, and the movement of the table (2) also stops abruptly.On the other hand, the vibration damping mechanism ( 6).

Since the conductor plate is held between a pair of magnetic poles υ and (c), eddy currents (as shown in Figure 4) occur due to electromagnetic induction.
c) is occurring. This eddy current (c) provides strong resistance similar to viscous force to the movement of the conductive plate. In other words, the eddy current (c) has an allocating effect. This allocation effect is proportional to the speed of the conductor plate (a), and the magnetic pole Qυ.

It is proportional to the square of the magnetic field strength due to @, and the conductor plate (a)
is inversely proportional to the resistance of Therefore, even if the table (2) suddenly stops at the target position, vibrations that occur during the sudden stop are suppressed. As a result, the table (2) can be positioned at high speed and with high accuracy of 0.1 μm or less. Moreover, an unreasonable load will not be applied to the drive mechanism (5) when the table (2) is stopped.

Deterioration of the nut plate I and feed screw (1) can be prevented.

In the above embodiment, one 1-allocation mechanism is provided, but an arbitrary number of them may be installed at arbitrary positions as necessary. Furthermore, a magnet may be attached to the table side, and a conductor plate may be fixed to the base side. Furthermore, the magnet may be an electromagnet instead of a permanent magnet. When using this electromagnet, by magnetizing the power supply tab to the electromagnet only when the table is stopped, it is possible to prevent the magnet from acting as a braking force for table movement and enable high-speed table movement. can. Furthermore, this case has the advantage that the damping force can be controlled by adjusting the amount of power supplied. moreover,
A pneumatic cylinder, a hydraulic cylinder, a linear motor, etc. may be used as the drive mechanism.

〔Effect of the invention〕

Since the table device of the present invention utilizes the vibration damping effect of eddy current, it is possible to almost completely suppress vibrations that occur when the table suddenly stops. Therefore, for the guide,
Since the table and magnets are non-contact, no frictional force is generated, and this combined with the fact that the table can be positioned at high speed and with high precision. Furthermore, deterioration of the drive mechanism that drives the table can be prevented.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a table device according to an embodiment of the present invention, Fig. 2 is a sectional view of the main part of the guide mechanism, Fig. 3 is an enlarged view showing the main part of the allocation mechanism, and Fig. 4 is a diagram showing the eddy current. FIG. (2)...table, (4)...guidance mechanism. (5)... Drive mechanism, (6)... Allocation mechanism. (b)...Conductor plate, @...Magnet. Agent: Patent attorney Kensuke Chika (and 1 other person)

Claims (1)

[Claims] a guide mechanism that has a table and statically supports the table so as to be slidable in a certain direction; a drive mechanism that drives the table forward and backward along the certain direction; and a main surface provided along the direction of movement of the table. A table comprising: a conductive plate having a conductive plate and a magnet for inducing an eddy current in the conductive plate, and a vibration damping mechanism in which either one of the conductive plate and the magnet is attached to the table. Device.