JP5254977B2 - Linear actuator with dustproof mechanism - Google Patents

Description

  The present invention relates to a linear actuator with a dustproof mechanism, for example, a linear actuator with a dustproof mechanism suitable for use as a drive mechanism used in a clean room.

  So far, the present applicant and its related corporations have proposed various actuators (including a motion guide device that guides the movement of a moving object) having a dustproof mechanism as disclosed in Patent Documents 1 and 2 below. doing. For example, a linear actuator with a dustproof mechanism proposed in Patent Document 1 below has a function capable of reliably preventing dust leakage from an opening of an actuator housing, and a dustproof belt at the opening of the actuator housing In order to avoid interference with the projecting portion of the moving stage, a detouring means for the dustproof belt is provided for the moving stage.

  The linear actuator with a dustproof mechanism disclosed in the following Patent Document 1 will be described with reference to FIG. FIG. 9 is a diagram for explaining the configuration of a linear actuator with a dustproof mechanism according to the prior art, in which (a) shows a plane of the linear actuator with a dustproof mechanism, and (b) in FIG. 9 shows a dustproof mechanism. The front of the attached linear actuator is shown, and (c) in the figure shows a cross section of the linear actuator with a dustproof mechanism.

  As shown in FIG. 9, a linear actuator 1 with a dustproof mechanism according to the prior art includes an elongated box-shaped housing member 2, a ball screw 3 supported in a rotatable state in the housing member 2, and rotation of the ball screw 3. A moving stage 4 that reciprocates linearly according to the movement and a drive motor 5 for rotating the ball screw 3 are provided.

  The housing member 2 includes a horizontal substrate 21, a pair of left and right vertical side plates 22, 23 that extend vertically from the upper surface of the horizontal substrate 21 and extend in parallel with the ball screw 3, and front and rear ends of the vertical side plates 22, 23. And attached end blocks 24 and 25. One end block 24 supports one end of the ball screw 3 in a rotatable state. Further, the other end portion of the ball screw 3 is supported by the other end block 25 in a rotatable state, 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 a right angle toward the inside to form left and right horizontal upper plate portions 22a and 23a. A central partition plate 26 is disposed between the left and right horizontal upper plate portions 22a and 23a, and the front and rear ends of the central partition plate 26 are fixedly attached 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 central partition plate 26. Similarly, a right opening 28 is formed between the horizontal upper plate portion 23 a and the central partition plate 26.

  The openings 27 and 28 are sealed by dustproof belts 29 and 30 that are wider than these openings. These dustproof belts 29 and 30 are bridged between the end blocks 24 and 25 along the lower surfaces of the horizontal upper plate portions 22a and 23a and the central partition plate 26, respectively.

  As described above, the housing member 2 seals the horizontal substrate 21, the vertical side plates 22 and 23 (horizontal upper plate portions 22 a and 23 a), the central partition plate 26, the end blocks 24 and 25, and the openings 27 and 28. The partition chamber is partitioned into a box shape by the dustproof belts 29 and 30, and covers the ball screw 3 to play a role of retaining dust generated from the actuator in the partition chamber.

  Next, the moving stage 4 includes a nut block 41 in which a ball screw nut screwed to the ball screw 3 is formed, a lower plate 42 fixed to the upper surface of the nut block 41, and the lower plate 42. An intermediate plate 43 fixed to the upper surface and an upper plate 44 fixed to the upper surface of the intermediate plate 43 are provided. Both side surfaces of the nut block 41 are slidably supported in the axial direction of the ball screw 3 by linear guide rails 31 attached to the inside of the housing member 2.

  The moving stage 4 is configured such that the upper plate 44 is located outside the housing member 2, and the middle plate 43, the lower plate 42, and the nut block 41 are located inside the housing member 2. In other words, the upper plate 44 is configured to project outward from the openings 27 and 28, and can be applied with a moving force by being connected to the guide object.

  In addition, horizontally extending rollers 61 to 66 are installed on the left and right side surfaces of the moving stage 4 that are located inside the housing member 2 as a bypass means for bypassing the dustproof belts 29 and 30 in a rotatable state. ing. With respect to the arrangement positions of these rollers 61 to 66, the rollers 63 and 64 in the central portion are arranged so as to be one step lower than the rollers 61, 62, 65, and 66 on both ends in the axial direction. The roller denoted by reference numeral 65 is installed at a position facing the roller 66, but does not appear in Fig. 9. Therefore, in the following description, it will be written in parentheses.

  Then, the dustproof belts 29 and 30 are bridged between the rollers 61 to 66 so that the upper plate 44 protruding outside from the openings 27 and 28 and the dustproof belts 29 and 30 do not interfere with each other. Has been. That is, the dustproof belts 29 and 30 are laid over the rollers 61 to 66 so as to bypass the lower portion of the protruding portion of the upper plate 44, and specifically, the left side ((a) in FIG. 9). The dust-proof belt 29 on the upper side of the paper passes through the upper side of the front roller 61, spans the lower side of the central roller 63, and further passes the upper side of the rear roller (65). Similarly, the dust-proof belt 30 on the right side (the lower side of the paper in FIG. 9A) passes through the upper side of the front roller 62 and is bridged to the lower side of the central roller 63. The upper side of the roller 66 is passed.

  Since the linear actuator 1 with a dustproof mechanism according to the prior art has the above-described configuration, the openings 27 and 28 formed along the movement locus of the moving stage 4 are blocked by the dustproof belts 29 and 30. It is possible to always maintain the state. Accordingly, the dust generated from the sliding portion of the ball screw 3 and the ball screw nut included in the nut block 41, the sliding portion of the nut block 41 and the linear guide rail 31, and the like is separated from the opening 27, which the housing member 2 includes. No leakage occurs to the outside via 28.

  Moreover, in the linear actuator 1 with a dust-proof mechanism according to the prior art, the dust-proof belts 29 and 30 are disposed inside the housing member 2, and each dust-proof belt with respect to the moving stage 4 that moves along the openings 27 and 28. Since 29 and 30 can be detoured below the moving stage 4, even when the moving stage 4 moves, the sealed state of the openings 27 and 28 by the dustproof belts 29 and 30 can always be maintained. ing.

  Furthermore, in the linear actuator 1 with a dust-proof mechanism according to the prior art, in addition to the above-described configuration, an intake port for sucking air from the housing member 2 is provided. That is, as shown in FIG. 9, the pair of left and right vertical side plates 22 and 23 are formed with housing intake ports 22b and 23b, and the air in the housing member 2 is passed through these housing intake ports 22b and 23b. It is possible to suck.

  Further, intake ducts 7 and 8 are attached to the horizontal upper plate portions 22a and 23a formed at the upper ends of the vertical side plates 22 and 23, and the intake ducts 7 and 8 and the horizontal upper plate portions 22a and 22a, Between 23a, narrow duct inlets 7b, 8b extending along the openings 27, 28 are open. Accordingly, dust generated in the housing is sucked into the external dust collector (not shown) from the housing intake ports 22b and 23b formed in the left and right vertical side plates 22 and 23 and removed from the housing member 2.

  In a clean room or the like, an air flow in a downflow state is generally formed. Accordingly, when an intake operation is performed via the duct intake ports 7b and 8b arranged at positions adjacent to the openings 27 and 28, dust leaking from the openings 27 and 28 is taken together with the downflow airflow. It is sucked into the mouths 7b and 8b. Therefore, it is possible to surely remove the dust without scattering the dust around.

JP 2000-266151 A JP 2005-188600 A

  However, when the linear actuator with a dustproof mechanism according to Patent Document 1 was able to exhibit an appropriate dustproof function when used under general conditions, a very long stroke is required. And when speeding-up was requested | required, it had the problem that a dustproof function will fall.

  In other words, when the speed of the guide motion by the linear actuator is increased, the internal pressure of the actuator housing rapidly increases due to the high-speed movement of the moving stage, and dust is likely to leak particularly at both ends of the actuator housing. There has occurred.

  Further, if the linear actuator is lengthened to satisfy the required long stroke, the length of the dustproof belt will be increased accordingly. As a result, the dustproof belt hangs due to its own weight, and a problem arises that a gap is easily formed in the opening of the actuator housing.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a reliable dust-proof function over the entire stroke range even if the actuator has a longer stroke or a higher speed. It is an object of the present invention to provide a linear actuator with a dustproof mechanism capable of exhibiting the above.

  A linear actuator with a dust-proof mechanism according to the present invention includes a ball screw and a ball screw nut that engages with the ball screw, and is capable of reciprocating linear movement in the axial direction of the ball screw as the ball screw rotates. A moving stage, a housing member installed so as to cover at least the ball screw, an opening formed in the housing member along a movement trajectory of the moving stage, and the housing for sealing the opening A dustproof belt disposed on the inside of the member, and overlaps with the moving stage in order to realize movement of the moving stage along the opening while maintaining the sealing of the opening by the dustproof belt. A linear actuator with a dustproof mechanism in which a bypass means for bypassing the dustproof belt at a position is provided on the moving stage A is, the housing member, it characterized in that it comprises a suction means for sucking the dust-proof belt portion in contact with the dustproof belt.

  In the linear actuator with a dustproof mechanism according to the present invention, the suction means can be configured by a suction path formed by conduction through the housing member and a suction force generation source connected to the suction path. .

  Further, in the linear actuator with a dustproof mechanism according to the present invention, the suction path can be formed by having a plurality of suction ports provided at a predetermined interval at a location where the housing member contacts the dustproof belt. .

  Furthermore, it is preferable that the linear actuator with a dustproof mechanism according to the present invention is configured such that the number of suction ports formed is larger at both end sides than the central portion of the housing member.

  Moreover, it is preferable that the linear actuator with a dustproof mechanism according to the present invention is configured such that the suction force exerted on the dustproof belt by the suction means is greater at both end sides than the central portion of the housing member.

  The summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  According to the present invention, it is possible to provide a linear actuator with a dustproof mechanism capable of exhibiting a reliable dustproof function over the entire stroke range, for example, even if the actuator is speeded up.

  In addition, according to the present invention, the close contact state between the housing member and the dustproof belt can be maintained at all times, and therefore, for example, even an actuator having a long stroke or a high speed can be reliably obtained over the entire stroke range. It is possible to provide a linear actuator with a dustproof mechanism capable of exhibiting a dustproof function.

It is the schematic for demonstrating the characteristic of the linear actuator with a dust-proof mechanism which concerns on 1st Embodiment. It is the schematic for demonstrating the characteristic of the linear actuator with a dust-proof mechanism which concerns on 2nd Embodiment. It is a figure for demonstrating the structure of the linear actuator with a dustproof mechanism which concerns on 3rd Embodiment, (a) shows the plane of a linear actuator with a dustproof mechanism, and (b) in the figure is a linear actuator with a dustproof mechanism. (C) has shown the cross section of the linear actuator with a dust-proof mechanism. It is the schematic for demonstrating the characteristic of the linear actuator with a dust-proof mechanism which concerns on 3rd Embodiment. It is a longitudinal cross-sectional schematic diagram for demonstrating the characteristic of the linear actuator with a dustproof mechanism which concerns on 4th Embodiment. In a linear actuator with a dustproof mechanism concerning a 4th embodiment, it is a figure which illustrates the case where a suction opening is installed in the both end side of a housing member. In a linear actuator with a dustproof mechanism concerning a 4th embodiment, it is a figure which illustrates the case where a suction opening is installed in the bottom face side of a housing member. In a linear actuator with a dustproof mechanism concerning a 4th embodiment, it is a figure which illustrates the case where a suction opening is installed in the side of a housing member. It is the schematic for demonstrating the characteristic of the linear actuator with a dustproof mechanism which concerns on 5th Embodiment. It is the schematic for demonstrating the characteristic of the linear actuator with a dustproof mechanism which concerns on 6th Embodiment. It is a fragmentary longitudinal cross-sectional view for demonstrating the principal part of the linear actuator with a dustproof function which concerns on 7th Embodiment. It is a figure for demonstrating the structure of the linear actuator with a dustproof mechanism which concerns on a prior art, (a) shows the plane of a linear actuator with a dustproof mechanism, and (b) in the figure shows the front of the linear actuator with a dustproof mechanism. In the figure, (c) shows a cross section of a linear actuator with a dustproof mechanism.

Explanation of symbols

  2 Housing member, 3 Ball screw, 4 Moving stage, 5 Drive motor, 7, 8 Air intake duct, 7b, 8b Air inlet for duct, 21 Horizontal board, 22, 23 Vertical side plate, 22a, 23a Horizontal upper plate part, 22b , 23b Housing inlet, 24, 25 End block, 26 Central partition plate, 27, 28 Opening, 29, 30 Dust-proof belt, 31 Linear guide rail, 41 Nut block, 42 Lower plate, 43 Middle plate, 44 Upper plate 61, 62, 63, 64, (65), 66 Roller, 1, 90, 100, 110, 120, 130, 140, 150 Linear actuator with dustproof mechanism, 91, 91a, 101, 113, 123a, 123b, 123c Suction port, 111, 151a, 152a Partition, 112, 122 Opening port, 1 1 separator plate, 142 filter (filtering means), 150 suction means, alpha moving partition, beta flow compartment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. The following embodiments do not limit the invention according to each claim, and all combinations of features described in the embodiments are essential for the solution of the invention. Not exclusively. In the following description of each embodiment, members that are the same as or similar to those described in the background art column are assigned the same reference numerals, and descriptions thereof are omitted.

[First Embodiment]
The linear actuator 90 with a dustproof mechanism according to the first embodiment has substantially the same configuration as the linear actuator 1 with a dustproof mechanism according to the above-described prior art, but in order to further improve the dustproof function, As shown in FIG. 1, the arrangement position of the suction port 91 is characteristic. That is, FIG. 1 is a schematic view for explaining the characteristics of the linear actuator 90 with a dustproof mechanism according to the first embodiment, but the linear actuator 90 with a dustproof mechanism according to the first embodiment is a housing member 2. The suction port 91 is provided on the end side of the head.

  The reason why the above configuration is adopted will be described. When the moving stage 4 moves at a high speed and moves to the end of the housing member 2, the internal pressure rapidly increases at the end of the housing member 2. In addition, since dust generated inside the housing member 2 is likely to gather on the end side of the housing member 2, coupled with the increase in the internal pressure, in the linear actuator 1 with a dustproof mechanism according to the prior art, the end of the housing member 2 There has been a phenomenon that the dustproof function is reduced.

  Therefore, in the linear actuator 90 with a dustproof mechanism according to the first embodiment, by installing the suction port 91 on the end side of the housing member 2, the dust collection environment is bad, and dust is likely to leak due to an increase in internal pressure. This is intended to further enhance the suction effect on the end side of the housing member 2. Then, as in the linear actuator 90 with a dustproof mechanism according to the first embodiment shown in FIG. 1, the moving stage 4 is moved at a high speed by providing the suction port 91 on the end side of the housing member 2. However, a suitable dustproof function can be exhibited.

[Second Embodiment]
In the first embodiment described above, the linear actuator 90 with a dustproof mechanism in which the suction port 91 is installed on the end side of the housing member 2 has been described. In a second embodiment to be described next, a linear actuator that employs a configuration for further enhancing the dustproof function will be described.

  FIG. 2 is a schematic view for explaining the characteristics of the linear actuator 100 with a dustproof mechanism according to the second embodiment. As shown in FIG. 2, the linear actuator 100 with a dustproof mechanism according to the second embodiment is provided with a plurality of suction ports 101 on the side surface side of the housing member 2, and the number of these suction ports 101 is formed. The housing member 2 is configured to be larger at both end sides than the center portion.

  As described in the first embodiment, in this type of linear actuator with a dustproof mechanism 1, 90, 100, there is a problem that the dustproof function at the end of the housing member 2 is deteriorated. Therefore, in the second embodiment shown in FIG. 2, the suction ports 101 are formed at both ends of the housing member 2 as a means for increasing the dust suction force at both ends of the housing member 2 where the dust environment deteriorates. It was configured to increase the number.

  By adopting such a configuration, it is possible to provide the linear actuator 100 with a dustproof mechanism that can exhibit an appropriate dustproof function even if the moving stage 4 moves at a high speed and the internal pressure of the housing member 2 increases. ing.

[Third Embodiment]
In the first and second embodiments described above, the linear actuators 90 and 100 with a dustproof mechanism in the case where the installation positions and the formation locations of the suction ports 91 and 101 are devised have been described. In a third embodiment to be described next, a flow path of suction air that flows inside the housing member 2 is secured, and appropriate dust suction is attempted.

  Here, FIG. 3 is a figure for demonstrating the structure of the linear actuator 110 with a dust-proof mechanism based on 3rd Embodiment, (a) in the figure shows the plane of a linear actuator with a dust-proof mechanism, b) shows the front of the linear actuator with a dustproof mechanism, and (c) in the figure shows a cross section of the linear actuator with a dustproof mechanism.

  As shown in FIG. 3, in the linear actuator 110 with a dustproof mechanism according to the third embodiment, a plurality of partition walls 111 are formed inside the housing member 2, and the interior of the housing member 2 is moved by the partition walls 111. It is divided into four moving sections α and suction air flow sections β. By dividing the interior of the housing member 2 in this way, a flow path of the suction air is secured, and the suction air including dust can smoothly flow inside the housing member 2 and can be smoothly discharged to the outside. It will be possible.

  A plurality of openings 112 are provided between the plurality of partition walls 111 so that the flow of suction air between the moving section α and the flow section β is further optimized.

  Further, in the linear actuator 110 with the dustproof mechanism according to the third embodiment, it is preferable that the suction port 113 and the opening port 112 are arranged to face each other as shown in FIG. Since dust is mainly generated in the moving section α and is introduced into the flow section β after being included in the suction air and passing through the opening 112, the suction opening 113 and the opening 112 are arranged opposite to each other. Suction air containing dust is guided to the suction port 113, and efficient dust suction is possible.

  Further, the plurality of partition walls 111 are provided upright on the horizontal substrate 21 constituting the housing member 2, and the moving stage 4 can be divided by a very simple component configuration and manufacturing process. Therefore, according to the third embodiment, it is possible to obtain the linear actuator 110 with a dustproof mechanism having an improved dustproof function without increasing the manufacturing cost.

[Fourth Embodiment]
The linear actuator 110 with a dustproof mechanism according to the third embodiment described above is an apparatus characterized in that the flow section β is formed on both side surfaces of the movement section α. Various changes can be made to the arrangement relationship with the section α. For example, in the case of a linear actuator with a dustproof mechanism according to a fourth embodiment described below, the case where the flow section β is formed on the bottom surface side of the moving section α is illustrated. FIG. 5 is a schematic longitudinal sectional view for explaining the characteristics of the linear actuator 120 with a dustproof mechanism according to the fourth embodiment.

  As shown in FIG. 5, the linear actuator 120 with a dustproof mechanism according to the fourth embodiment has a cavity functioning as a flow section β formed on the bottom surface side of the housing member 2, and the flow section β has a plurality of opening portions. A conduction state with the moving section α is realized through the port 122. In the case of the embodiment shown in FIG. 5, the opening 122 is provided at a total of three positions, one at each end of the linear actuator 120 and one at the center. Various changes can be made to the location where the opening 122 is formed, but the opening 122 on both ends of the linear actuator 120, which is expected to have a particularly high dust concentration, is an essential location.

  The housing member 2 can also be formed by aluminum extrusion, but in this case, in order to reduce the weight of the housing member 2, it is common to form a cavity in the thick portion on the bottom surface side of the member. Has been done. Therefore, the linear actuator 120 with the dustproof mechanism can be manufactured at a very low cost by forming the flow section β using the cavity formed during the extrusion process in order to reduce the weight. However, the method of providing the flow section β on the bottom surface side of the housing member 2 is not limited to the method of using the cavity formed at the time of extrusion processing. For example, as in the case of the third embodiment described above, there are a plurality of methods. A member corresponding to the partition wall 111 may be used at a position 121 in FIG.

  In addition, as for the formation place of the suction port in the case of the linear actuator 120 with the dustproof mechanism according to the fourth embodiment in which the flow section β is formed on the bottom surface side of the moving section α, for example, as shown in FIG. It is possible to adopt a configuration in which suction ports 123a are installed on both ends of the member 2, and as shown in FIG. 5B, it is on the bottom surface side of the housing member 2 and corresponds to the opening 122. It is also possible to form the suction port 123b at a position where it does. Furthermore, as shown in FIG. 5C, it is also preferable to form the suction port 123 c on the side surface side of the housing member 2 and at a position corresponding to the opening port 122.

  According to the linear actuator 120 with the dust-proof mechanism according to the fourth embodiment described above, the flow section β can be provided without increasing the number of parts and almost without increasing the outer shape. And can exhibit significant effects in terms of versatility.

[Fifth Embodiment]
The linear actuators 110 and 120 with the dustproof mechanism according to the third and fourth embodiments described above have been described with respect to the case where the interior of the housing member 2 is divided into the movement section α and the flow section β by the partition walls 111 and 121. The flow compartment β can also be formed outside the housing member 2. For example, in the case of the linear actuator with a dustproof mechanism according to the fifth embodiment described below, the case where the flow section β is formed outside the housing member 2 is illustrated. FIG. 6 is a schematic diagram for explaining the characteristics of the linear actuator 130 according to the fifth embodiment.

  As shown in FIG. 6, the linear actuator 130 with a dustproof mechanism according to the fifth embodiment has a cavity that functions as a flow section β formed on the side surface side of the housing member 2, and the flow section β is the housing member 2. It communicates with the movement section α inside. In the case of the embodiment shown in FIG. 6, one flow section β is provided at each end of the linear actuator 130 with a dustproof mechanism. Various changes can be made with respect to the formation location of the flow compartment β, but in particular the flow formation β on both end sides of the linear actuator 130 with a dustproof mechanism that is expected to increase the dust concentration is an essential formation location. It is. Further, a suction port 91 a is formed at the end of the housing member 2 in the moving direction of the moving stage 4.

  As described above, when the flow section β is formed, even when the internal stage suddenly rises at the end of the housing member 2 by moving the moving stage 4 at a high speed and moving toward the end of the housing member 2, This is the case where the air compressed by the high-speed movement of the moving stage 4 through the flow section β can be released to the rear of the moving stage 4, the rapid increase in internal pressure can be suppressed, and the moving stage 4 is moved at high speed. However, a suitable dustproof function can be exhibited.

[Sixth Embodiment]
Although the linear actuators 110, 120, and 130 with the dustproof mechanism according to the third to fifth embodiments described above have been described with respect to the case where the rapid increase in the internal pressure of the housing member 2 is suppressed by the flow section β, the flow section β It is also possible to suppress an increase in the internal pressure of the housing member 2 without forming the. For example, in the case of a linear actuator with a dustproof mechanism according to a sixth embodiment described below, an external exhaust port that communicates the inside and the outside of the housing member 2 is formed at the end of the housing member 2 through a filtering means. This is illustrated as an example. FIG. 7 is a schematic view for explaining the characteristics of the linear actuator 140 according to the sixth embodiment.

  As shown in FIG. 7, the linear actuator 140 with a dustproof mechanism according to the sixth embodiment has an external exhaust port 143 formed at the end of the housing member 2, and communicates the inside and the outside of the housing member 2. ing. Further, a filter 142 is attached to the external exhaust port 143 as a filtering means, and the air inside the housing member 2 is filtered by the filter 142 and discharged. The filter 142 may be attached inside the housing member 2 or outside as long as the air discharged from the external exhaust port 143 can be filtered. The filter 142 can be appropriately selected according to the size of dust generated inside the housing member 2, and for example, a HEPA filter or a ULPA filter can be applied.

  As described above, when the external exhaust port 143 is formed, even if the internal pressure of the housing member 2 suddenly increases due to the high-speed movement of the moving stage 4, the compressed air is filtered by the filter 142 and the external exhaust port 143 143 can be discharged to the outside of the housing member 2, so that dust generated inside the housing member 2 can be prevented from leaking to the outside, and even when the moving stage 4 is moved at high speed It has become possible to exhibit a suitable dustproof function.

  Further, as shown in FIG. 7, the linear actuator 140 with a dustproof mechanism according to the sixth embodiment has a separation plate 141 formed inside the housing member 2, and a position sandwiched between the separation plate 141 and the housing member 2. A passage as shown by an arrow A is formed. A suction port 144 is formed at the upper end of the housing member 2. As shown in FIG. 7, the position where the suction port 144 is formed is formed at the position of the passage indicated by the arrow A, and is formed so as to ensure the negative pressure of the air passing through the passage. ing.

  As described above, the linear actuator 140 with the dustproof mechanism according to the sixth embodiment secures the negative pressure of the air sucked from the air inlet 144 by the separation plate 141, and therefore efficiently sucks air from the air inlet 144. Can be done.

[Seventh Embodiment]
As shown in FIG. 8, in the linear actuator 150 with a dustproof mechanism according to the seventh embodiment, the pair of left and right vertical side plates 22 and 23 constituting the housing member 2 and the dustproof belts 29 and 30 in the central partition plate 26 come into contact. An adsorbing means 150a for adsorbing the dust-proof belts 29 and 30 by sucking the portions is provided.

  The suction means 150 a is connected to the suction paths 151 and 152 formed by conduction between the vertical side plates 22 and 23 made of an aluminum alloy extruded material and the central partition plate 26, and these suction paths 151 and 152. It is comprised with the attraction | suction force generation source which is not shown in figure. As for a suction force generation source (not shown), an external dust collector may be used, or a known suction device using a suction pump or the like may be used.

  The suction paths 151 and 152 formed in the vertical side plates 22 and 23 and the central partition plate 26 are a plurality of suction ports 151a provided at predetermined intervals in the longitudinal direction at the contact points with the dustproof belts 29 and 30. The suction force applied from the suction force generation source can be applied over the entire length of the dustproof belts 29 and 30 in the longitudinal direction. By adopting such a configuration, the linear actuator 1 with the dustproof mechanism according to the seventh embodiment can reliably maintain the sealed state of the openings 27 and 28 by the dustproof belts 29 and 30. Therefore, for example, even if the length of the dustproof belts 29 and 30 is increased by increasing the overall length of the linear actuator to increase the stroke, the suction means 150a prevents the dustproof belts 29 and 30 from drooping due to their own weight. can do.

  Further, the number of the suction ports 151 a and 152 a described above is preferably configured so as to be larger at both end sides than the central portion of the housing member 2. That is, when the speed of the linear actuator is increased, a phenomenon occurs in which the internal pressure in the housing member 2 increases when the moving stage 4 comes to both ends of the housing member 2. In addition, it has been confirmed that dust and the like generated inside the housing member 2 have a property that they are more likely to gather at both end sides than the central portion of the housing member 2. That is, when the speed of the linear actuator is increased, an adverse condition that the internal pressure rapidly increases at a location in the housing member 2 where the dust environment is bad is achieved. Therefore, by configuring the suction ports 151a and 152a to be more installed at both ends than the central portion of the housing member 2, the adsorbing force of the dustproof belts 29 and 30 at locations where dust is likely to leak can be obtained. It is possible to realize a linear actuator capable of enhancing and exhibiting a reliable dustproof function.

  In the case of the suction paths 151 and 152 shown in FIG. 8, the positions of the suction ports 151a and 152a are aligned in the longitudinal section, that is, the positions of the suction ports 151a and 152a are the same in the left-right direction of the linear actuator. The case where it comprised is illustrated. However, the installation positions of the suction ports 151a and 152a are not limited to those shown in FIG. 8, and are viewed from the top surface of the linear actuator so that the positions of the suction ports 151a and 152a do not overlap in the left-right direction of the linear actuator, for example. It may be formed in a zigzag arrangement.

  As mentioned above, although preferred embodiment of this invention was described, the technical scope of this invention is not limited to the range as described in said each embodiment. Various modifications or improvements can be added to the above embodiments.

  For example, by realizing a linear actuator with a dustproof mechanism that combines the first embodiment and the second embodiment, and a linear actuator with a dustproof mechanism that combines each of the first to seventh embodiments described above. Thus, it is possible to obtain a linear actuator that exhibits a more suitable dustproof function.

  The shape and number of partitions 111 and opening 112, 122, or the positions and number of suction ports 91, 101, 113, 123a, 123b, 123c, etc. are used and installed for the linear actuator with dustproof mechanism. It is possible to change arbitrarily according to conditions. For example, it is possible to improve the dustproof effect by configuring the number of the opening openings 122 opened on the bottom surface side of the housing member 2 described in the fifth embodiment to be larger at both end sides than the central portion of the housing member 2. It is suitable at the point made to do.

  Furthermore, in the seventh embodiment described above, by using the suction paths 91 and 92 having the same diameter as the single suction force generation source, the suction force exerted on the dustproof belts 29 and 30 from the suction ports 91a and 92a is The case where the suction ports 91a and 92a are substantially the same has been described as an example. However, since the suction force exerted on the dustproof belts 29 and 30 by the suction means 90 may be configured to be larger at both ends than the central portion of the housing member 2, the installation locations of the suction ports 91a and 92a are as described above. For example, even if the suction ports are arranged at equal intervals in the longitudinal direction, the diameter of the suction port is changed so that the suction force is larger at both ends than the central portion of the housing member 2. The same effect as that of the linear actuator 1 with the dustproof mechanism of the sixth embodiment described above can also be obtained by connecting different sources of suction force generation sources having different suction forces between the central portion and both ends of the housing member 2. Can be obtained.

  Furthermore, in the above-described seventh embodiment, the case where the suction paths 91 and 92 and the suction force generation source (not shown) are used as the suction means 90 that generates the suction force has been described as an example. The adsorption | suction means of this invention is not restricted to the thing of the form mentioned above. That is, the suction means according to the present invention can exert a suction force over the entire length of the dustproof belts 29 and 30, and can always maintain the sealed state of the openings 27 and 28 by the dustproof belts 29 and 30. If it is good. And as such an adsorption | suction means, the adsorption | suction tape installed in the horizontal upper board parts 22a and 23a and the center partition plate 26 can be illustrated, for example. By using a plurality of suction tapes having different suction forces, the suction force exerted on the dustproof belt by the suction means can be configured to be greater at both ends than the central portion of the housing member.

  It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

Claims (5)

A ball screw,
A moving stage that has a ball screw nut that engages with the ball screw, and is reciprocally linearly movable in the axial direction of the ball screw as the ball screw rotates;
A housing member installed over at least the ball screw;
An opening formed in the housing member along a movement locus of the moving stage;
A dust-proof belt disposed inside the housing member to seal the opening;
And for detouring the dustproof belt at a position overlapping with the moving stage in order to realize movement of the moving stage along the opening while maintaining sealing of the opening by the dustproof belt. In the linear actuator with a dustproof mechanism provided with a bypass means on the moving stage,
A linear actuator with a dustproof mechanism, wherein the housing member is provided with suction means for sucking the dustproof belt at a position where the housing member comes into contact with the dustproof belt. The linear actuator with a dustproof mechanism according to claim 1 ,
The adsorption means includes
A suction path formed through the interior of the housing member;
A suction force generation source connected to the suction path;
A linear actuator with a dustproof mechanism, characterized by comprising: The linear actuator with a dustproof mechanism according to claim 2 ,
The linear actuator with a dustproof mechanism, wherein the suction path is formed to have a plurality of suction ports provided at predetermined intervals at contact portions of the housing member with the dustproof belt. The linear actuator with a dustproof mechanism according to claim 3 ,
A linear actuator with a dustproof mechanism, wherein the number of suction ports formed is greater at both ends than the central portion of the housing member. The linear actuator with a dustproof mechanism according to claim 1 ,
A linear actuator with a dustproof mechanism, wherein the suction force exerted by the suction means on the dustproof belt is greater at both ends than the center of the housing member.

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