JP2000190149A - Moving table - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moving table of double-thrust structure capable of giving a stable preload without being influenced by the initial wear of the rolling surface and rolling elements and also the shape accuracy. SOLUTION: A moving table includes a movable board 2 supported on a stationary board 1 through an upper 3a and a lower thrust bearing 3b, wherein the movable board 2 is composed of a body 32 of movable board and a preloading plate 33, and the lower thrust bearing 3b is interposed between the under-fixed rolling surface 9b of the stationary board 1 and the under- movable rolling surface 17b of the plate 33, while a coil spring 36 is interposed between, the body 32 of movable board and the plate 33, and by its resilience, a requisite constant preload is given to the upper 3a and the lower thrust bearing 3b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving table used in a device for manufacturing or inspecting a printed circuit board, and the like.
Particularly, the present invention relates to a moving table having a double thrust structure.

[0002]

2. Description of the Related Art A double-thrust moving table is
As shown in FIG. 5, it comprises a fixed platen 1, a movable platen 2, upper and lower thrust bearings 3a, 3b, and a driving device 4.

The fixed plate 1 has a seat 6 fixed to a base 5 and a horizontal portion 7 provided on the seat 6, and a circular hole 8 is formed at the center of the horizontal portion 7. Provided. Circular hole 8
The upper surface of the horizontal portion 7 around the upper surface is an upper fixed rolling surface 9a, and the lower surface is a lower fixed rolling surface 9b.

The movable platen 2 has a stage 11 arranged on the upper surface of the horizontal portion 7 of the fixed platen 1 and a preload plate 12 arranged on the lower surface, and has a smaller diameter than the circular hole 8 and is arranged inside the movable hole 2. The intermediate spacer 13 and the connecting plate 14 are integrally connected to each other. The intermediate spacer 13 is a stage 1
1 is connected to the lower surface of the intermediate spacer 13 via a connecting plate 14 and is connected to the lower surface of the preload plate 1 by bolts 15.
2 are overlapped and integrated by bolts 16.

[0005] The movable platen 2 has an upper movable rolling surface 1 on the lower surface of the stage 11 opposed to the upper fixed rolling surface 9a.
7a, and a lower movable rolling surface 17b facing the lower fixed rolling surface 9b is formed on the upper surface of the preload plate 12.

An upper thrust bearing 3a is interposed between the upper fixed rolling surface 9a and the upper movable rolling surface 17a, and a lower thrust bearing is provided between the lower fixed rolling surface 9b and the lower movable rolling surface 17b. The bearing 3b is interposed. Each of these thrust bearings 3a and 3b has an annular flat retainer 18 holding a number of steel balls 19 as rolling elements.

A cylinder 22 of the drive unit 4 is fixed to the fixed plate 1 via a bracket 21, and a piston 23 is connected to the stage 11 via a flexible joint 24.

A work table 25 is mounted on the upper surface of the stage 11.

In the above-described conventional moving table, a work is placed on a work table 25, and is moved in one direction, two directions (XY) or a θ direction by a drive unit 4 according to the work content. Even if an eccentric load or the like is applied on the work table 25, a preload is applied to the steel balls 19 of the upper and lower thrust bearings 3a and 3b so as to suppress the lifting of the stage 11 and obtain a required rigidity. The preload amount is set by controlling the thickness (plane difference) of the intermediate spacer 13. That is, the method of applying the preload is the fixed position preload method.

[0010]

As described above, in a so-called double thrust structure which is supported by two conventional upper and lower thrust bearings, when the method of applying a preload is a fixed position preload method, the rolling surface In some cases, the preload may decrease due to the initial wear of the rolling elements, or the preload may fluctuate due to the shape accuracy of the rolling surface. In addition, it is difficult to adjust the thickness and working of the intermediate spacer for adjusting the preload amount, and there is a problem that it takes time to set an appropriate value.

Therefore, the present invention provides a moving table having a double-thrust structure bearing, in which the preload amount is stable,
It is another object of the present invention to provide a moving table whose management is easy.

[0012]

In order to solve the above-mentioned problems, the present invention comprises a combination of a fixed plate, a movable plate, a pair of upper and lower thrust bearings and a driving device. The movable platen has a fixed rolling surface and a lower fixed rolling surface, and the movable platen has an upper movable rolling surface facing above the upper fixed rolling surface and a lower movable rolling surface facing below the lower fixed rolling surface. The upper and lower thrust bearings are interposed between the upper fixed rolling surface and the upper movable rolling surface, and between the lower fixed rolling surface and the lower movable rolling surface, respectively. ,
In a moving table having the driving device interposed between the fixed plate and the movable plate, and supporting the movable plate with upper and lower thrust bearings so that the movable plate can freely move in a horizontal plane, the movable plate is The preloading plate includes one of the upper movable rolling surface and the lower movable rolling surface, and the other movable platen body, and an elastic member is interposed between the preloading plate and the movable platen body. Thus, a required constant pressure preload is applied to each of the thrust bearings.

The fixed plate has the upper fixed rolling surface and the lower fixed rolling surface formed around a center hole. The movable plate body has a stage having the upper movable rolling surface, and a lower surface of the stage. And a connecting portion penetrating the center hole with a required gap, and a supporting plate integrated at the lower end of the connecting portion, and the supporting member is provided on the supporting plate via the elastic member. And a lower movable rolling surface opposed to the lower fixed rolling surface is formed on the preload plate.

The fixed plate has the upper fixed rolling surface and the lower fixed rolling surface formed around a center hole. The movable plate body has a stage having the upper movable rolling surface, and a lower surface of the stage. The center hole is formed with a connecting portion with a required gap, and the preload plate is coupled with the lower end of the connecting portion and the preload plate with a vertical movement margin by a bolt penetrating the movable plate body, A configuration can be adopted in which an elastic member is interposed between the head of the bolt and the movable plate body.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, the moving table of the embodiment is basically similar to the conventional moving table described above.
It comprises a fixed platen 1, a movable platen 2, upper and lower thrust bearings 3a, 3b, and a drive device 4.

The fixed board 1 has a seat 6 fixed to the base 5 and a horizontal portion 7 provided on the seat 6, and a circular hole 8 is formed at the center of the horizontal portion 7. Provided. Circular hole 8
The upper surface of the peripheral part of the upper surface becomes the upper fixed rolling surface 9a, and the lower surface becomes the lower fixed rolling surface 9b.

The movable platen 2 includes a stage 11 arranged on the upper surface of the horizontal portion 7 of the fixed platen 1, a support plate 31 arranged on the lower surface, and a connection interposed between the stage 11 and the support plate 31. The movable plate main body 32 includes a plate 14 and an annular preload plate 33 described later.

The above-mentioned connecting plate 1 constituting the movable platen body 32
A boss portion 4 penetrates at a predetermined gap from the inner periphery of the circular hole 8 and is provided at a central portion of the support plate 31.
And the stage 11 and the support plate 31 are connected and integrated by bolts 15 and 16, respectively.

An annular spring receiving surface 35 is provided on the upper surface of the support plate 31 outside the boss 34. The above-mentioned preload plate 33 is disposed on the spring receiving surface 35, and a pair of coil springs 36 is provided between the spring receiving surface 35 and the preload plate 33.
Are interposed at predetermined intervals in the circumferential direction (see FIG. 2).

The movable platen 2 has an upper movable rolling surface 17a facing the upper fixed rolling surface 9a on the lower surface of the stage 11, and the lower fixed rolling surface on an upper surface of the preload plate 33. A lower movable rolling surface 17b corresponding to the surface 9b is formed.

An upper thrust bearing 3a is interposed between the upper fixed rolling surface 9a and the upper movable rolling surface 17a, and a lower thrust bearing is provided between the lower fixed rolling surface 9b and the lower movable rolling surface 17b. The bearing 3b is interposed. Each of these thrust bearings 3a and 3b has an annular flat cage 18 holding a number of steel balls 19 as rolling elements.

A cylinder 22 of the driving device 4 is fixed to the fixed plate 1 via a bracket 21, and a piston 23 is connected to the stage 11 via a flexible joint 24.

A work table 25 is mounted on the upper surface of the stage 11.

In the moving table described above, a work is placed on the work table 25 and moved in one direction, the XY direction or the θ direction by the driving device 4 according to the work content, as in the conventional case.

The preload for suppressing the floating of the stage 11 even when an eccentric load or the like is applied on the work table 25 is obtained by applying the spring force of the coil spring 36 to the upper thrust bearing 3 b via the preload plate 33. A reaction force is applied to the upper thrust bearing 3a via the stage 11 of the movable platen body 32, and the thrust bearings 3a and 3b are applied by being pressed against the fixed platen 1, respectively.

Instead of the coil spring 36, an annular disc spring 36 'having the same curvature as that of the preload plate 33 is provided between the spring receiving surface 35 and the preload plate 33, as in the modification shown in FIG. It may be interposed between them.

In another modification shown in FIG. 4, the movable plate body 32 is provided with a connecting portion 14 'integrally on the lower surface of the stage 11, and a preload plate 33' is arranged at the lower end of the connecting portion 14 '.
The preloading plate 33 'is fixed to the lower end of a bolt 37 penetrating the movable platen body 32. The preload plate 33 ′ has a lower movable rolling surface 17 b facing the lower fixed rolling surface 9 b of the fixed platen 1.

The upper movable rolling surface 17a facing the upper fixed rolling surface 9a of the fixed platen 1 is provided on the lower surface of the stage 11, similarly to the above-described one, and the upper thrust bearing 3a is provided between them. Interposed and lower fixed rolling surface 9b
The lower thrust bearing 3b is interposed between the lower thrust bearing 17b and the lower movable rolling surface 17b.

The preloading plate 33 'has its bolt head 38 inserted into the recess 39 of the stage 11 and its head 3
A coil spring 41 is interposed between 8 and the bottom of the recess 39. The coil spring 41 is connected to the preload plate 3 via the bolt 37.
3 'is lifted, and its lower movable rolling surface 17b presses the lower thrust bearing 3b against the fixed platen 1. In the pressed state, there is a clearance δ between the preload plate 33 ′ and the connecting portion 14 ′, and the spring force of the coil spring 41 is applied to the lower thrust bearing 3.
b) and exerts a reaction force on the upper thrust bearing 3a to apply a required preload to both bearings 3a and 3b.

In any of the above embodiments, an air spring or another elastic member can be used instead of the coil spring 36, the disc spring 36 ', and the coil spring 41.

As described above, the preload applying method according to the present invention is a so-called constant pressure preload method in which a constant preload is applied by applying the elastic force of the elastic member to each of the thrust bearings 3a and 3b.

In each of the above embodiments, the preloading plates 33, 33 'are in contact with the lower thrust bearing 3b. However, by providing these preloading plates 33, 33' on the upper part, the upper thrust bearing 3b is provided. A structure that makes contact with 3a can be adopted. In this case, upper movable rolling surfaces 17a are formed on the lower surfaces of the preload plates 33 and 33 '.

[0034]

As described above, the present invention employs a so-called constant pressure preload system in which a preload is applied to one of the thrust bearings of the double thrust structure by the elastic force of the elastic member via the preload plate. Accordingly, it is possible to prevent a decrease in the preload amount due to the initial wear of the rolling surface and the rolling element. In addition, fluctuations in the preload amount at the time of stage movement due to poor precision in the shape of the rolling surface are suppressed, and the load on the driving device is stabilized, and the movement accuracy and posture of the stage are stabilized.

Furthermore, since a quantitative preload value can be given by managing the elastic force of the elastic member, the preload management is easier than in the fixed position preload system.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is a cross-sectional plan view of the above.

FIG. 3 is a partial sectional view of a modification of the above.

FIG. 4 is a partial sectional view of another modification of the above.

FIG. 5 is a sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed board 2 Movable board 3a Upper thrust bearing 3b Lower thrust bearing 4 Drive device 5 Base 6 Seat part 7 Horizontal part 8 Circular hole 9a Upper fixed rolling surface 9b Lower fixed rolling surface 11 Stage 12 Preload plate 13 Intermediate spacer 14 Connecting plate 14 'Connecting portion 15 Bolt 16 Bolt 17a Upper movable rolling surface 17b Lower movable rolling surface 18 Cage 19 Steel ball 21 Bracket 22 Cylinder 23 Piston 24 Joint 25 Work table 31 Support plate 32 Movable plate body 33, 33' Preload plate 34 Boss part 35 Spring receiving surface 36 Coil spring 36 'Disc spring 37 Bolt 38 Head 39 Recess 41 Coil spring

Claims (3)

[Claims] 1. A fixed plate, a movable plate, a combination of a pair of upper and lower thrust bearings and a driving device, wherein the fixed plate has an upper fixed rolling surface and a lower fixed rolling surface on both upper and lower surfaces, respectively. The board has an upper movable rolling surface facing above the upper fixed rolling surface and a lower movable rolling surface facing below the lower fixed rolling surface. Between the dynamic rolling surface, and between the lower fixed rolling surface and the lower movable rolling surface, the upper and lower thrust bearings are interposed, respectively.
In a moving table having the driving device interposed between the fixed plate and the movable plate, and supporting the movable plate with upper and lower thrust bearings so that the movable plate can freely move in a horizontal plane, the movable plate is The preloading plate includes one of the upper movable rolling surface and the lower movable rolling surface, and the other movable platen body, and an elastic member is interposed between the preloading plate and the movable platen body. A moving table, wherein a predetermined constant pressure preload is applied to each of the thrust bearings. 2. The fixed plate having the upper fixed rolling surface and the lower fixed rolling surface formed around a center hole, wherein the movable plate body has a stage having the upper movable rolling surface; And a supporting plate integrated with the lower end of the connecting hole and penetrating the center hole with a required gap, and a supporting plate integrated at a lower end of the connecting portion. 2. The moving table according to claim 1, wherein the preload plate is provided, and a lower movable rolling surface facing the lower fixed rolling surface is formed on the preload plate. 3. The fixed plate has the upper fixed rolling surface and the lower fixed rolling surface formed around a center hole, and the movable plate body has a stage having the upper movable rolling surface. And a connecting portion with the center hole having a required gap. The preload plate is connected to the lower end of the connecting portion by a bolt that penetrates the movable platen main body with a margin for vertical movement. The moving table according to claim 1, wherein an elastic member is interposed between the head of the bolt and the movable plate body.