JPH023416Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a positioning table used in, for example, semiconductor manufacturing equipment, various precision instruments, and the like.

(Prior Art) Conventionally, as this type of positioning table, for example, one shown in FIG. 4 is common. That is, in this positioning table, a DC motor 3 with an encoder 3a attached thereto is fixed to a mounting plate 2 fixed to a base 1, and a support plate 4 fixed to the base 1 is fixed to a mounting plate 2 fixed to a base 1.
and 5 are provided with bearings 6 and 7, respectively, and a ball screw shaft 8 is supported by these bearings, and
By tightening the nut 10 through the collar 9 and tightening the lock nut 11, the ball screw shaft 8 is prevented from moving laterally. Further, the rotating shaft 3b of the motor and the tip end 8a of the ball screw shaft 8 are connected by a coupling 12, and a moving table 14 is fixed to a moving nut 13 that engages with the ball screw shaft 8. When the DC motor 3 rotates to a predetermined degree, the ball screw shaft 8 rotates via the coupling 12, and as a result, the movable nut 13 and the movable table 14 fixed thereto move in the direction of the arrow along a guide portion (not shown). The moving table 14 also stops at the same time as the DC motor 3 stops.

In addition, although not shown as other devices,
A fine movement table is further provided on the moving table 14 shown in FIG. 4, and this fine movement table is equipped with a piezoelectric element actuator, and after coarse movement by the movement table, the piezoelectric element actuator is operated to finely move the fine movement table. There is also known a system in which a highly accurate stopping position is secured as a result.

(Problems to be solved by the invention) However, in the conventional positioning table shown in FIG. 4, although the rotation amount of the DC motor 3 is detected by, for example, the encoder 3a,
The stop position accuracy of the moving nut 13 and the table 14 is on the order of several μm. For example, in order to satisfy the accuracy of 1 μm or less, the number of encoder divisions must be increased, and the momentum encoder must be larger than the motor. There was a problem that I had no choice but to do. In addition, a highly accurate ball screw 8 and moving nut 13
There was also the problem that the momentum device as a whole became expensive. In addition, the latter combination of a coarse movement table and a fine movement table also requires a ball screw to drive the coarse movement table, which, combined with the structural complexity, inevitably results in an expensive product. It was hot.

(Means for solving the problem) In order to solve the above problem, this invention eliminates the use of expensive ball screws and nuts, simplifies the structure, and uses a common eccentric for both coarse and fine movement. This is intended to reduce manufacturing costs by allowing the process to be carried out using a ring. That is, this invention includes a table 22 that is slidable relative to the bed 21 and has a table protrusion 25, a means for fixing the bed 21 and the table 22, and a control motor 31 that is slidable relative to the bed 21. a traveling block 28 having an eccentric wheel 33 fixed therein and displaced by the rotation of the control motor; means for bringing the traveling block 28 and the table protrusion 25 into proximity; and means for fixing the traveling block 28 and the bed 21. The object of the present invention is to provide a positioning table equipped with the following.

(Embodiments of the invention) The invention will be described in detail below based on the embodiments shown in FIGS. 1 to 3.

First, to explain the configuration, 21 is a bed, and 22 is a table that moves on the encoder 21 in the front and rear directions (X ₁ and X ₂ directions). That is, the table 22
As shown in FIG. 2, it is mounted so as to be slidable along the upper surface of the bed 21 via a roller guide 23. A means for fixing the table 22 and the bed 21, in this embodiment electromagnets 24 and 24' embedded in the table 22, is provided. That is, when current is applied to these electromagnets 24, 24', the table 22 is fixed to the bed 21.

A tail protrusion 25 is provided at or near the center of the table 22 in the front-rear direction, and when moving, it moves within a recess 26 provided in the bed 21 and comes into contact with an eccentric wheel 33, which will be described later. A contact surface 27 is provided. 28 is inside the recess 26 of the bed 21 in the front and rear directions (X ₁ and X ₂ directions)
It is a moving block that can be moved. That is, the traveling block 28 is slidably mounted on the bed 21 via a roller guide 29. Between the traveling block 28 and the bed 21, a fixing means for both is provided, in this embodiment, electromagnets 30, 30' are embedded in the traveling block 28 side. That is, when current is applied to these electromagnets 30, 30', the traveling block 28 is fixed to the bed 21.

A main body of a control motor, in this embodiment a pulse motor 31, is fixed inside the traveling block 28, and a motor rotation shaft 3 protrudes from both sides of the pulse motor 31.
2 and 32' respectively have eccentric plates 3 of eccentric wheels 33.
4 is fixed. 36 is a bearing interposed between the eccentric wheel 33 and the eccentric plate 34.

As shown in FIG. 3, when the center point M of the eccentric plate 34 is on the horizontal plane P passing through the center point N of the motor rotation shaft 32, and is located in front (to the right in the figure) of the center point N (hereinafter referred to as , when the eccentric wheel 33 is at the reference position), the outer circumferential surface of the short diameter side of the eccentric wheel 33,
End surface 3 of the traveling block 28 on the table protrusion 25 side
7, there is a slight step f.

Proximity means, in this embodiment, electromagnets 38, 38' embedded in the traveling block 28 side, are provided between the table protrusion 25 and the traveling block 28 to bring them close to each other. That is, when current is passed through these electromagnets 38, 38',
When the traveling block 28 is fixed and the table 22 is released, the table 22 is attracted to the traveling block 28 side, and on the other hand, when the traveling block 28 is released, the table 22 is
In the case of being fixed, the traveling block 28 is attracted to the table protrusion 25 side. In these cases, since the above-described step f is provided, the table protrusion 25 and the running block 28 do not come into direct contact, and a gap at least equal to or larger than the step f is provided between them.

Next, the operation of this embodiment having the above configuration will be explained. When slightly moving the eccentric wheel 33 forward by a predetermined distance from the reference position shown in FIG.
24' to fix the table to the bed 21, while electromagnets 38, 38' and electromagnets 30, 3
At 0', the running block 28 is kept in a released state without being energized, and a pulse signal corresponding to the distance to be slightly moved forward is given to the pulse motor 31. Then, the motor rotation shafts 32, 32' rotate by a predetermined angle in the direction of arrow R, and the outer peripheral surfaces of the eccentric wheels 33, 33' touch the abutting surfaces 2.
Since you press 7, the reaction is to move block 2.
8 moves forward (moves to the right in Figure 3).

The amount of advance is x, the eccentric plate 34 (motor rotation shaft 32)
If the rotation angle of is θ and the eccentricity of the eccentric wheel is e, then x
Move forward by =e(1-cosθ). Running block 2
Immediately after the advance of step 8 is completed, the electromagnets 30, 30'
energizes to fix the running block 28 to the bed 21, then energizes the electromagnets 38, 38',
The electromagnets 24, 24' are de-energized, and the same number of pulses as before are applied to the pulse motor 31 to reverse the motor rotation shafts 32, 32'. Then, the eccentric plates 34, 34' are also reversed (in the opposite direction of arrow R), and the eccentric wheels 33, 33' return to their reference positions (the positions shown in FIG. 3). During this return period, the table protrusion 25 is attracted toward the traveling block 28 by the electromagnets 38, 38', so the contact surface 27 closely follows the outer peripheral surface of the eccentric wheel 33, and the traveling block 28 is first Move forward by an amount equal to the distance x moved forward. In this way, fine movement can be made in accordance with the number of pulses.

Next, to explain the case of slightly moving backwards,
First, the electromagnets 30, 30' are energized to fix the traveling block 28 to the bed 21, while the electromagnets 24, 30' are energized.
24' and the electromagnets 38, 38' to release the table 22, a predetermined pulse is applied to the pulse motor 31 to rotate the eccentric plate 34 by a predetermined angle in the direction of the arrow R. Then, the contact surface 27 of the table protrusion 25 is pushed by the outer circumferential surface of the eccentric wheel 33, so that the table 22 moves backward (to the left in FIG. 3) by a predetermined amount. Therefore, the electromagnets 24 and 24' are energized to move the table 22 to the bed 2.
1, while energizing the electromagnets 38 and 38',
The electromagnets 30 and 30' are de-energized to release the running block 28, and the same number of pulses as before are applied to the pulse motor 31 to reverse the rotation (in the direction opposite to the direction of arrow R), thereby rotating the eccentric wheel 33. Return to the standard position (position shown in Figure 3). During this return period, the traveling block 28 moves backward while the outer circumferential surface of the eccentric wheel 33 always closely contacts and follows the contact surface 27 due to the attractive force of the electromagnets 38, 38'.

Next, move forward or backward (hereinafter referred to as coarse movement)
The case where this is done will be explained. This case is the same as the case of fine movement described above except that the rotation angle of the pulse motor 31 is increased. For example, when the pulse motor 31 is rotated 180 degrees, the traveling block 28 is
It is possible to move the table 22 by a distance twice the amount of eccentricity e, and by returning the eccentric wheel 33 to the reference position with the subsequent 180° rotation (forward or reverse rotation is fine), the table 22 can be moved the same distance. By repeating the above procedure, it is possible to move the motor forward or backward (coarse movement) by an arbitrary integral multiple of the eccentricity e.

Of course, it goes without saying that the intermediate value between the distances of the above-mentioned fine movement and coarse movement can be arbitrarily selected.

In the above explanation, the electromagnet 38 was energized and de-energized, but originally this electromagnet 38
Its role is to bias the table 25 and the traveling block 28 toward each other, so in some cases it can be kept energized all the time, or a permanent magnet can be used instead of an electromagnet. . Further, instead of a magnet, a tension spring may be provided between the two to bring the two closer to each other.

(Summary of the invention) As described above, the positioning table according to the invention has a structure in which the table 2 is slidable with respect to the bed 21 and has the table protrusion 25.
2, a traveling block 28 having an eccentric wheel 33 that is slidable relative to the bed 21 and has a control motor 31 fixed therein and is displaced by the rotation of the control motor; the bed 21 and the table 22;
2, a means for bringing the traveling block 28 and the table protrusion 25 into proximity, and a means for fixing the traveling block 28 and the bed 21.

(Effect of the invention) Therefore, according to this positioning table, by operating the two fixing means at the appropriate time and applying a signal to the control motor 31 according to a predetermined program, the table 22 can be made to make a predetermined precise fine movement. In addition to being able to provide motion consisting of forward and backward movement, coarse movement and forward and backward movement, or a combination thereof, it is also possible to eliminate expensive ball screws, nuts, etc. that were indispensable to conventional devices, and the structure is relatively simple and inexpensive. It has the advantage that it can be manufactured.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of an embodiment of the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, Fig. 3 is an enlarged view for explaining the table protrusion, running block, eccentric wheel, etc.; FIG. 4 is an explanatory side view showing a conventional positioning table. 21... bed, 22... table, 23...
Roller guide, 24... Electromagnet, 25... Protrusion, 26... Recess, 27... Contact surface, 28... Running block, 29... Roller guide, 30...
Electromagnet, 31... Pulse motor, 32... Motor rotating shaft, 33... Eccentric wheel, 34... Eccentric plate, 36
... Bearing, 37 ... End face, 38 ... Electromagnet.

Claims (1)

[Scope of utility model registration request] A table 22 that is slidable relative to the bed 21 and has a table protrusion 25; a traveling block 28 that is slidable relative to the bed 21 and has a control motor 31 fixed therein; A fixing means, a fixing means for fixing the bed 21 and the traveling block 28, and a means for proximate the table 22 and the traveling block 28 are provided, and the eccentric wheel 33, which is displaced by the rotation of the control motor 31, is attached to the table protrusion 25. A positioning table characterized in that the table 22 and the traveling block 28 can be moved relative to each other by engaging with a contact surface 27 provided on the table.