JP2000266151A - Linear actuator with dustproof mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dust generated in a linear actuator from leaking out through opening parts formed along a moving locus of a moving stage, in a linear actuator. SOLUTION: A housing 2 of this linear actuator 1 has a box shape, and opening parts 27, 28 are formed on the upper surface of it along moving loci of projecting parts (connecting parts) 44b, 44c of a moving stage 4. The opening parts 27, 28 are closed by dustproof belts 29, 30 arranged inside the housing. Rollers 61 to 66 for detouring respective belt 29, 30 to sides in the housing are attached on the moving stage 4 so that respective belts 29, 30 may not interfere with the projecting parts of the moving stage. The opening parts 27, 28 are reliably closed by the dustproof belts 29, 30. Air suction is performed from outer suction ports 8a, 8b arranged near the opening parts 27, 28 and from suction ports 22b, 23b arranged in the opening parts to reliably prevent dust generation from the linear actuator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear actuator with a dustproof mechanism suitable for use as a drive mechanism used in a clean room or the like.

[0002]

2. Description of the Related Art Various types of linear actuators are known. As one of the generally known linear actuators, there is a linear actuator having a configuration in which a rotary motion of a motor is converted into a reciprocating linear motion of a moving stage using a ball screw and a ball screw nut.

[0003]

When a linear actuator is used in a clean room or the like, a sliding portion in which a ball screw and a ball screw nut mesh with each other, or a slide between a moving stage and a guide rail for guiding the same. It is necessary to prevent dust generated from moving parts from leaking into the clean room.

Here, an opening is formed in the actuator housing along a movement locus of a connecting portion connecting the moving stage and the ball screw. Therefore, it is necessary to reliably prevent dust from leaking from the opening.

An object of the present invention is to propose a linear actuator with a dustproof mechanism capable of reliably preventing dust from leaking from an opening of an actuator housing.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a shaft member and a movable member mechanically engaged with the shaft member and capable of reciprocating along the shaft member. A linear actuator having a stage, a partition plate disposed between the shaft member and the moving stage, and an opening formed in the partition plate along a movement locus of a connecting portion of the moving stage to the shaft member. Department and
A dust-proof belt arranged along the opening on the side of the shaft member of the partition plate to close the opening, and the dirt-proof belt is detoured to the connecting member on the side of the shaft member. And detour means attached to the moving stage.

Here, as the detour means, a means for detouring the dust-proof belt from the connecting part by using a roller, or a means for detouring the dust-proof belt from the connecting part by using an arc-shaped sliding surface or the like. Can be adopted.

When the moving stage is supported by the pair of left and right connecting portions, a pair of left and right openings formed along the moving trajectories of the connecting portions are formed. In this case, a through hole of the center partition plate disposed between the pair of left and right openings may be formed in the moving stage.

In a typical linear actuator, the shaft member is disposed in a compartment (actuator housing) defined by a member including the partition plate. In this case, by providing an intake port for sucking air from inside the compartment, dust generated inside the compartment can be reliably sucked and removed.

[0010] In addition, if a suction port is attached to the outside of the compartment near the opening, the dust leaking from the opening can be reliably sucked and removed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a linear actuator with a dustproof mechanism to which the present invention is applied will be described below with reference to the drawings.

FIGS. 1A to 1C are a plan view, a front view, and a cross-sectional view showing a linear actuator of this embodiment.
As shown in these figures, the linear actuator 1
An elongated box-shaped housing 2, a ball screw 3 rotatably supported therein, a moving stage 4 that reciprocates linearly in accordance with the rotation of the ball screw 3, and a ball screw 3 for rotating the ball screw 3. It has a drive motor 5.

The housing 2 includes a horizontal substrate 21 and a pair of left and right vertical side plates 22 and 23 (partition plates) which stand vertically from the upper surface of the horizontal substrate 21 and extend in parallel with the ball screw 3.
And end blocks 24, 25 attached to the front and rear ends of the vertical side plates 22, 23. One end of the ball screw 3 is rotatably supported by one end block 24. The other end of the ball screw 3 is rotatably supported by the other end block 25, and is connected to the drive motor 5 through the block 25.

The upper end portions of the left and right vertical side plates 22 and 23 are bent at right angles toward the inside, so that the left and right horizontal upper plate portions 2 are formed.
2a and 23a. These left and right upper plate portions 22
A central partition plate 26 is disposed between the a and 23a, and the front and rear ends of the central partition plate 26 are attached and fixed to end blocks 24 and 25, respectively. As a result,
A left opening 27 extending in the axial direction of the ball screw 3, that is, in the moving direction of the moving stage 4, is formed between the horizontal upper plate portion 22 a and the center partition plate 26. Similarly, a right opening 28 is formed between the horizontal upper plate portion 23a and the center partition plate 26.

The openings 27 and 28 are closed by dust-proof belts 29 and 30 wider than these openings. These dust-proof belts 29 and 30 are stretched between the end blocks 24 and 25 along the lower surfaces of the horizontal upper plate portions 22a and 23a and the center partition plate 26, respectively.

As described above, the housing 2 includes the substrate 21,
It is partitioned into a box by the side plates 22, 23, the upper plate portions 22a, 23a, the center partition plate 26, and the end blocks 24, 25, and the dustproof belts 29, 30 closing the openings 27, 28. It is a compartment.

Next, the moving stage 4 includes a nut block 41 having a ball screw nut screwed into the ball screw 3, a lower plate 42 fixed to the upper surface of the nut block 41, and a lower plate 42. An intermediate plate 43 fixed to the upper surface of the plate 42 and an upper plate 44 fixed to the upper surface of the intermediate plate 43 are provided. Both sides of the nut block 41 are
The ball screw 3 is slidably supported in the axial direction of the ball screw 3 by a linear guide rail 31 mounted inside the ball screw 3.

FIG. 2 is an exploded perspective view for explaining the shapes of the three plates 42 to 44 supported by the nut block 41. Referring to FIG.
The lower plate 42 is a flat plate. The middle plate 43 fixed thereon is provided with a rib 43a having a rectangular cross-section extending in the front-rear direction at the center thereof. The rollers 61 to 66 are rotatably supported. The rollers 63, 64 at the center are located one step lower than the rollers 61, 62, 65, 66 at both ends.

Also, overhangs 43b, 43c project horizontally from both sides of the rib 43a, and the upper surfaces of these overhangs 43b, 43c are flush with the upper surface of the rib, but the lower surface is directed from front to rear to the center. Inclined surface 43d, 4
3e, 43f, and 43g, and arc-shaped grooves 43h, 4h, which are cut out upward in a substantially semicircular shape at the apexes of these inclined surfaces.
3i, in which rollers 63 and 64 are located.

The upper plate 44 has a flat main body portion 44.
a, and projecting portions 44b, 44c extending in the front-rear direction and projecting downward from both left and right portions of the lower surface of the main body portion, and these projecting portions 44b, 44c
It is fixed to the upper surface of. The center partition plate 2 is formed by the groove between the protruding surfaces 44b and 44c and the upper surface of the middle plate 43.
A through hole 45 through which 6 passes is defined. Further, lower end portions of the left and right side surfaces of the main body portion 44a are cut into L shapes, and L-shaped grooves 44d and 44e extending in the front-rear direction are formed. The left and right horizontal upper plate portions 22a, 23a of the housing 2 are opposed to the L-shaped grooves 44d, 44e with a slight gap.

As described above, the upper plate 44 of the moving stage 4 is located outside the housing 2, and the middle plate 43, the lower plate 42 and the nut block 41 are located inside the housing 2. A pair of left and right protrusions 44b, 44 formed on the lower surface of the plate 44
It is in a state of being connected via c. The pair of left and right openings 27 and 28 described above are formed along the movement trajectory of the projecting portions 44b and 44c as these connecting portions.

Here, in this embodiment, each of the projections (connecting portions) 44b and 44c and the dust-proof belts 29 and 30 do not interfere with each other. It is spanned. That is, the left dust-proof belt 29 passes over the front roller 61, is bridged below the central roller 63 along the inclined surface 43d, and is further extended along the inclined surface 43e. Passing through the upper side. Similarly, the right dust-proof belt 30 also passes over the front roller 62, is bridged below the central roller 63 along the inclined surface 43f, and further extends over the inclined surface 43g.
Along the upper side of the rear roller 66.

In the linear actuator 1 of this embodiment having the above-described structure, as can be seen from FIG.
Reference numeral 28 is closed by dustproof belts 29 and 30.
Therefore, dust generated from a sliding portion of the ball screw 3 between the ball screw 3 and the nut block 41 and a sliding portion between the nut block 41 and the linear guide rail leak to the outside through these openings 27 and 28. It can be prevented from leaving.

In this embodiment, the dust-proof belts 29 and 30 are arranged inside the housing 2 and, along with this arrangement, the projections 44b and 44c of the moving stage 4 which move along the openings 27 and 28, respectively. Thus, the dust-proof belts 29 and 30 are detoured downward. If the internal pressure increases due to the pumping action generated in the housing due to the movement of the moving stage 4, each of the dust-proof belts 29, 30
Is pressed against the horizontal upper plate portions 22a and 23a and the center partition plate 26 from the inside of the housing. Therefore, an excellent dustproof effect can be obtained as compared with the case where the dustproof belt is arranged outside the housing.

Further, in this embodiment, the width of the openings 27 and 28 of the housing 2 is made as small as possible by forming a through hole 45 in the moving stage 4 and arranging the center partition plate 26 therethrough. . As a result, the amount of dust leakage can be reduced as compared with the case where a wide opening is opened in the housing 2.

On the other hand, the linear actuator 1 of the present embodiment has an intake port for sucking air from inside the housing, in addition to the above configuration. 1 and 3
As shown in FIG.
2b and 23b are formed, and the air in the housing can be sucked through these air inlets.

As shown by imaginary lines, intake ducts 7 and 8 having a rectangular cross section are attached to horizontal upper plate portions 22a and 23a formed at the upper ends of the side plates 22 and 23, respectively. Ducts 7, 8 and horizontal upper plate portions 22a, 23
A narrow inlets 7b, 8b extending along the openings 27, 28 are open between the openings a, a.

Therefore, the dust generated in the housing is sucked into the external dust collectors (not shown) from the air inlets 22b, 23b formed in the left and right side plates 22, 23, and is removed from the housing.

In a clean room or the like, a downflow airflow is generally formed. Therefore, when the suction operation is performed through the suction ports 7b and 8b disposed adjacent to the openings 27 and 28, the dust leaking from the openings 27 and 28 is sucked into the suction ports together with the downflow airflow. You. Therefore, it is possible to surely remove the dust without scattering the dust around. In particular, in this example, since the upper surface of the center partition plate is formed as a tapered surface inclined left and right, the airflow from above can be efficiently introduced along the tapered surface into the intake port 7.
b, 8b.

Furthermore, in the linear actuator 1 of the present embodiment, the openings 27 and 28 have an extremely narrow width by disposing the central partition plate 26. Therefore,
Even if the dust-proof belts 29 and 30 are omitted, and only the suction operation is performed from the above-described intake port, the target dust-proof performance can be obtained.

(Other Embodiments) Next, FIG.
(C) is a plan view, a front view, and a cross-sectional view showing a modified example of the linear actuator, and FIG. 5 is a perspective view showing a middle plate of a moving stage. Since the basic configuration of the linear actuator 100 is the same as that of the above-described actuator 1, corresponding portions are denoted by the same reference numerals, and description thereof will be omitted.

In the actuator 100 of the present embodiment, the pair of dust-proof belts 29 and 30 are
As a means for bypassing these belts so as not to interfere with b, 44c, instead of rollers,
An arcuate sliding surface that is convex downward is used.

That is, instead of the middle plate 43 having rollers (see FIG. 2), a middle plate 430 is provided as the middle plate constituting the moving stage 4.
The middle plate 430 includes a rib 431 having a rectangular cross-section extending in the front-rear direction at the center thereof. , 433, rear overhangs 434, 435, and center overhang 4
36 and 437 are formed. Central overhang 43
6, 437 are arc-shaped sliding surfaces 43 whose lower surfaces project downward.
6a and 437a. The front-side overhang portions 432 and 433 located on the front side have the arc-shaped sliding surface 43.
Convex arc-shaped sliding surfaces 432a and 433a facing each other at predetermined intervals are formed on 6a and 437a. Similarly, convex arc-shaped sliding surfaces 434a and 435a facing the arc-shaped sliding surfaces at predetermined intervals are also formed on the rear overhang portions 434 and 435 located on the rear side. I have.

The left dust-proof belt 29 is provided on the left sliding surface 4.
32a, 436a and 434a.
Similarly, the right dust-proof belt 30 is connected to the right sliding surface 433.
a, 437a and 435a. Each sliding surface slides along each of the dustproof belts 29 and 30 as the moving stage 4 moves.

[0035]

As described above, in the linear actuator according to the present invention, the opening of the housing (compartment chamber) formed along the movement locus of the moving stage is closed from the inside of the housing by the wide dust-proof belt. With this arrangement, the dust-proof belt is diverted into the housing so that the dust-proof belt does not interfere with the portion of the moving stage that moves along the opening. Therefore, according to the present invention, when the internal pressure of the housing is increased due to the movement of the moving stage, a superior dustproof effect can be obtained as compared with the configuration in which the dustproof belt is arranged outside the housing.

Further, the present invention employs a configuration in which an intake port for sucking air from inside the housing and an intake port arranged near the opening outside the housing are arranged. By performing the suction operation through these suction ports, dust generated in the housing can be sucked and collected by a dust collector or the like, so that dust generation from the linear actuator can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a plan view, a front view, and a cross-sectional view showing a linear actuator to which the present invention is applied.

FIG. 2 is an exploded perspective view showing an upper, middle, and lower plate constituting the moving stage of FIG. 1;

FIG. 3 is an explanatory view showing a dustproof mechanism of the linear actuator of FIG. 1;

FIG. 4 is a plan view, a front view, and a cross-sectional view showing a modification of the linear actuator of FIG. 1;

FIG. 5 is a perspective view showing a middle plate constituting the moving stage of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Linear actuator 2 Housing 21 Substrate 22, 23 Side plate 22a, 23b Horizontal upper plate part 22b, 23b Inlet port 24, 25 End block 26 Central partition plate 27, 28 Opening 29, 30 Dustproof belt 4 Moving stage 41 Nut block 42 Lower plate 43 Middle plate 44 Upper plate 44b, 44c Projecting portion (connection portion) 45 Through hole 61-66 Roller 7, 8 Intake duct 7b, 8b Inlet 100 Linear actuator 430 Middle plate 432a-437a Arc-shaped sliding surface

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[Procedure amendment]

[Submission date] April 6, 1999 (1999.4.6)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 5

FIG. 4

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J104 AA57 AA63 AA69 AA73 AA76 AA79 BA63 DA04 EA04 5H607 AA06 BB01 CC01 CC03 CC05 DD02 DD03 DD14 EE51 EE52 FF01 JJ10

Claims (9)

[Claims] 1. A linear actuator having a shaft member and a moving stage mechanically engaged with the shaft member and capable of reciprocating along the shaft member, between the shaft member and the moving stage. And an opening formed in the partition plate along a movement trajectory of the connecting portion to the shaft member in the moving stage, and the shaft of the partition plate for closing the opening. A dust-proof belt arranged along the opening on the member side; and a belt diverting means attached to the moving stage for diverting the dust-proof belt to the coupling member toward the shaft member. A linear actuator, characterized in that: 2. The linear actuator according to claim 1, wherein the belt detour means includes a roller for pressing the dust-proof belt against the shaft member. 3. The linear actuator according to claim 1, wherein the belt diverter has a sliding surface that presses the dust-proof belt against the shaft member. 4. The moving stage according to claim 1, wherein the moving stage includes a pair of left and right connecting portions, the opening includes a pair of left and right openings corresponding to the connecting portions, A linear actuator, comprising: a central partition disposed between a pair of openings; and the moving stage includes a through-hole extending through the central partition. 5. The intake port according to claim 1, wherein the shaft member is disposed in a compartment defined by a member including the partition plate, and further, air is sucked from inside the compartment. A linear actuator comprising: 6. The linear actuator according to claim 1, further comprising an intake port located outside the compartment near the opening. 7. A linear actuator having a shaft member and a moving stage mechanically engaged with the shaft member and capable of reciprocating along the shaft member, wherein the shaft member is disposed inside. A compartment, a partition plate disposed between the shaft member and the moving stage in the compartment, and an opening formed in the partition plate along a movement locus of a connecting portion of the moving stage to the shaft member. And a suction port for sucking air from inside the compartment. 8. The linear actuator according to claim 7, further comprising an intake port located outside the compartment near the opening. 9. The ball screw according to claim 1, wherein the shaft member is a ball screw, and a ball screw nut screwed to the ball screw is formed on the moving stage. A linear actuator.