Dustproof structure of linear actuator

Abstract

The objective is to provide a dustproof structure for a linear actuator that completely prevents dust from entering and has a dustproof and splashproof structure (IP65) that can withstand water jets. Furthermore, it aims to provide a dustproof structure for a linear actuator that can be used even in a vacuum processing chamber. [Solution] A dustproof structure for a linear actuator in which a rectangular movable body having a mouth-shaped end face moves in a linear motion, functionally connected to a ball screw shaft via a ball nut that screws onto the ball screw shaft by the rotation of the ball screw shaft located between a first end plate and a second end plate, A first bellows that covers the entire circumference from one end face of the moving body to the first end plate, and a sealing material that seals the one end face and the end face of the first bellows, A second bellows that covers the entire circumference from the other end face of the moving body to the second end plate, and a sealing material that seals the other end face and the end face of the second bellows, The device includes an electric motor fixing and dustproof cover provided on the outside of the first end plate, which covers the entire circumference from the coupling-side end face of the drive motor, which is connected by a coupling to one end of the ball screw shaft extending from the through hole of the first end plate, to the first end plate, fixing the drive motor to the first end plate and preventing dust from entering the through hole.

Description

Technical Field

[0001] The present invention relates to a dustproof structure of a dustproof linear actuator.

Background Art

[0002] When an actuator operates, dust such as thermal spraying raw materials formed on the surface of its components may enter the actuator, which may have an adverse effect on ball screws and linear guides. Therefore, a dustproof structure for preventing the intrusion of external dust is required. In addition, in a linear actuator used in a device such as a semiconductor manufacturing apparatus where minute contamination has an adverse effect on the device, a dustproof structure is also required to prevent contamination generated from the operating mechanism (such as ball screws and linear guides) from leaking outside the actuator. For this reason, in an actuator used in the atmosphere, a seal is provided as a dustproof structure, and by utilizing the pressure difference between the inside and outside of the actuator and maintaining the internal pressure higher than the atmospheric pressure, the intrusion of dust is prevented. Conversely, if the internal pressure is made lower than the atmospheric pressure, it is possible to prevent dust generated inside from leaking outside. However, in an actuator used in a vacuum processing chamber, such a seal method utilizing an air pressure difference cannot be applied.

[0003] Fig. 5 shows a dustproof structure of a conventional linear actuator. As shown in Fig. 5, the conventional dustproof structure includes a wiper seal on the outer periphery of the slider, and the wiper seal scrapes off foreign matter as it slides, thereby preventing the intrusion of foreign matter into the internal mechanism (such as ball screws and guides). With this dustproof structure, dustproof and drip-proof performance equivalent to IP54 can be obtained. However, with the conventional dustproof and drip-proof structure, it is difficult to completely seal the inside and outside of the housing of the linear actuator, and the dustproof and drip-proof performance remains at a level (IP54) that can be used in an indoor dust environment and a mild water droplet environment. Therefore, there is a need for an actuator with a dustproof and drip-proof structure that can completely prevent the intrusion of dust, which is a higher-level dustproof and drip-proof performance, and can withstand jet water (IP65). In addition, there is a need for a dustproof structure of a linear actuator that can also be used in a vacuum processing chamber.

Summary of the Invention

[0004] Therefore, the objective of this invention is to provide a dustproof structure for a linear actuator that completely prevents dust from entering and has a dustproof and drip-proof structure (IP65) that can withstand water jets. Furthermore, it is also to provide a dustproof structure for a linear actuator that can be used even in a vacuum processing chamber. [Means for solving the problem]

[0005] To solve the above problems, the dustproof structure for a linear actuator of the present invention is a dustproof structure for a linear actuator in which a rectangular moving body having a mouth-shaped end face moves in a linear motion, functionally connected to the ball screw shaft via a ball nut that screws onto the ball screw shaft by the rotation of the ball screw shaft located between a first end plate and a second end plate, A first bellows that covers the entire circumference from one end face of the moving body to the first end plate, and a sealing material that seals the one end face and the end face of the first bellows, A second bellows that covers the entire circumference from the other end face of the moving body to the second end plate, and a sealing material that seals the other end face and the end face of the second bellows, The present invention is characterized by comprising an electric motor fixing and dustproof cover provided on the outside of the first end plate, which covers the entire circumference from the coupling-side end face of the drive electric motor, which is connected by a coupling to one end of the ball screw shaft extending from the through hole of the first end plate, to the first end plate, fixing the drive electric motor to the first end plate and preventing dust from entering the through hole. [Effects of the Invention]

[0006] As described above, the present invention provides a dustproof structure for a linear actuator that completely prevents dust from entering and has a dustproof and drip-proof structure (IP65) that can withstand water jets. [Brief explanation of the drawing]

[0007] [Figure 1(A)] This is a front view of the dustproof linear actuator 1 according to the present invention. [Figure 1(B)] This is a plan view showing the line of sight for each arrow in the view of the dustproof linear actuator 1, which is an embodiment of the present invention. [Figure 1(c)] This is a view of a dustproof linear actuator 1, which is an embodiment of the present invention, as seen by arrow AA. [Figure 1(d)] This is a view of the dustproof linear actuator 1, which is an embodiment of the present invention, as seen from arrow BB. [Figure 1(e)] This is a view of a dustproof linear actuator 1, which is an embodiment of the present invention, as seen by arrow CC. [Figure 1(f)] This is a view of the dustproof linear actuator 1, which is an embodiment of the present invention, as seen from the DD arrow. [Figure 1(g)] This is a view of the dustproof linear actuator 1, which is an embodiment of the present invention, as seen from the JJ arrow. [Figure 1(h)] This is a view of the dustproof linear actuator 1, which is an embodiment of the present invention, as seen from arrow KK. [Figure 1(i)] This is a view of the dustproof linear actuator 1, which is an embodiment of the present invention, as seen from the arrow LL. [Figure 1(j)] This is a detailed view of part (j) of the dustproof linear actuator 1, which is an embodiment of the present invention. [Figure 1(k)] This is a detailed view of part (k) of the dustproof linear actuator 1, which is an embodiment of the present invention. [Figure 2(A)] This is a front view of a dustproof linear actuator 2, which is an embodiment of the present invention. [Figure 2(B)] This is a plan view of a dustproof linear actuator 2, which is an embodiment of the present invention. [Figure 2(c)] This is a view of the dustproof linear actuator 2, which is an embodiment of the present invention, as seen from the JJ arrow. [Figure 3] This is a front view of a dustproof linear actuator 1 with a base plate, which is an embodiment of the present invention. [Figure 4(A)]This is a front view of a dustproof linear actuator 3, which is an embodiment of the present invention. [Figure 4(B)] This is a plan view of the dustproof linear actuator 3, which is an embodiment of the present invention. [Figure 4(c)] This is a view of the dustproof linear actuator 3, which is an embodiment of the present invention, as seen by arrow AA. [Figure 4(d)] This is a view of the dustproof linear actuator 3, which is an embodiment of the present invention, as seen from arrow BB. [Figure 4(e)] This is a view of the dustproof linear actuator 3, which is an embodiment of the present invention, as seen from the JJ arrow. [Figure 5] This is a cross-sectional perspective view of a conventional dustproof linear actuator. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the dustproof structure for the linear actuator of the present invention (hereinafter also referred to as the dustproof linear actuator) will be described based on the drawings. The drawings schematically represent the constituent members and peripheral members of the dustproof linear actuator, and the dimensions and dimensional ratios on the drawings do not necessarily correspond to the actual dimensions and dimensional ratios. Furthermore, unless otherwise specified, in this specification, the drawings are based on the view of the paper in its normal orientation, with the top of the drawing being "up", the bottom being "down", the left being "left", and the right being "right". In addition, redundant explanations may be omitted as appropriate, and the same reference numeral may be assigned to the same member.

[0009] Figure 1(A) is a front view of the dustproof linear actuator 1 according to the present invention. The left end face of the slider 13 is fixed to the right end face of the bellows A15a along its entire circumference, and the right end face of the slider 13 is fixed to the left end face of the bellows B15b along its entire circumference. The left end face of the bellows A15a is fixed to the end plate A11, and the right end face of the end plate B12 is fixed to the end plate B12. An electric motor fixing / dustproof cover 17 is attached to the outer end face of the end plate A, and the drive shaft of the drive motor 16 is connected to the ball screw shaft 21 inside it.

[0010] Figure 1(B) is a plan view showing the line-of-sight directions of the respective arrow views of the dust-proof linear actuator 1 according to an embodiment of the present invention. Figure 1(c) is a view of the dust-proof linear actuator 1 according to an embodiment of the present invention taken along the line A-A. Figure 1(d) is a view of the dust-proof linear actuator 1 according to an embodiment of the present invention taken along the line B-B. Figure 1(e) is a view of the dust-proof linear actuator 1 according to an embodiment of the present invention taken along the line C-C. Figure 1(f) is a view of the dust-proof linear actuator 1 according to an embodiment of the present invention taken along the line D-D.

[0011] Figure 1(c) is a view of the dust-proof linear actuator according to an embodiment of the present invention taken along the line A-A, and shows the drive motor 16, the motor fixing / dust-proof cover 17, and the end plate A11.

[0012] Figure 1(d) is a view of the dust-proof linear actuator 1 according to an embodiment of the present invention taken along the line B-B, and shows the toggle 15a, the ball screw shaft 21a inside thereof, and the ball spline shafts 22a above and below it.

[0013] Figure 1(e) is a view of the dust-proof linear actuator 1 according to an embodiment of the present invention taken along the line C-C, and shows the ball spline nuts 22b and the ball spline shafts 22a above and below the inside of the slider 13. Also, the ball screw nut 21b and the ball screw shaft 21a are shown in the center. By rotating the ball screw shaft 21a, the ball screw nut 21b moves linearly, and accordingly, the ball spline nut 22b follows along the ball spline shaft 22a. Due to the guides of the ball splines provided on both sides, the slider 13 can always maintain a correct posture and perform a linear motion, and can also handle heavy-load conveyance. On the left and right near the center of the slider 13, two flow paths 31 are formed on each side. The flow paths 31 are air circulation holes between the space covered by the toggle A15a and the space covered by the toggle B15b. The flow paths 31 can keep the internal pressures of the two spaces partitioned by the slider 13 equal.

[0014] Figure 1(f) is a view of the dustproof linear actuator 1, an embodiment of the present invention, as seen from the DD arrow. An end plate B12 is provided at the end of the bellows B15b. The end plate B12 has four ventilation holes 32 equipped with filters, located on the left, right, top, and bottom near the center. When the dustproof linear actuator 1 is installed in the atmosphere, these holes filter dust from the outside; when installed in a vacuum, they allow internal air to be removed through the ventilation holes 32 equipped with filters.

[0015] Figure 1(g) is a view of a dustproof linear actuator 1, which is an embodiment of the present invention, as seen from the JJ arrow. One end of bellows A15a and B15b are fixed to end plates A11 and B12, respectively, along their entire circumference, and the other ends of bellows A15a and B15b are fixed to slider 13 along their entire circumference. In the center are a ball screw shaft 21a and ball screw nut 21b connected to the drive shaft of the drive motor 16, ball spline shafts 22a and ball spline nuts 22b arranged on both sides thereof, and slider 13 which moves linearly due to the rotation of ball screw shaft 21a.

[0016] Figure 1(h) is a view of a dustproof linear actuator 1, an embodiment of the present invention, as seen from the arrow KK. A flow path 31, slider 13, ball screw shaft 21a, and ball spline shafts 22a are shown above and below the center of the slider 13. On the outer circumference, bellows A15a and B15b are shown flanking the slider 13.

[0017] Figure 1(i) is a view of a dustproof linear actuator 1, an embodiment of the present invention, along the LL arrow. Ventilation holes 32 equipped with filters are located above and below the center of the end plate B12, and a ball screw shaft 21a is connected to the center of the end plate B12. Ball spline shafts 22a are shown above and below the ball screw shaft, and a bellows B15b is shown on the outer circumference.

[0018] Figure 1(j) is a detailed view of part (j) of the dustproof linear actuator 1, which is an embodiment of the present invention shown in Figure 1(g) (detailed mounting view of the drive motor 16 side). The drive motor 16 and the end plate A11 are connected by a motor fixing / dustproof cover 17 via adapter packing A45 (provided on both the drive motor 16 side and the end plate A11 side). The ball screw 21a passes through the end plate A11 and is connected to the drive shaft of the drive motor 16 by a coupling 18. The end of the motor fixing / dustproof cover 17 is bent into an L shape, and its periphery is tightly fixed to the end plate A11 via adapter packing A44. This structure makes the connection point between the drive motor 16 and the ball screw shaft 21a dustproof and waterproof. Furthermore, the bellows A15a and the end plate A11 are tightly fixed together by the packing 43, the bellows end plate 41 which presses the packing 43 against the end plate 11A and securely fixes it in place, and the bellows fixing plate 42, resulting in a dustproof and waterproof structure.

[0019] Figure 1(k) is a detailed view of part (k) of the dustproof linear actuator 1, which is an embodiment of the present invention shown in Figure 1(g). The slider 13 and the bellows A15a are tightly fixed together by a packing 43 interposed between the bellows fixing plate 42 and the bellows end face plate 41, creating a dustproof and waterproof structure.

[0020] Figure 2(a) is a front view of a dustproof linear actuator 2 using a ball screw shaft and a ball bush, which is an embodiment of the present invention; Figure 2(b) is a top view of the dustproof linear actuator 2; and Figure 2(c) is a view of the dustproof linear actuator 2 as seen through the JJ arrow.

[0021] A ball screw shaft 21a is connected to the drive motor 16 of the dustproof linear actuator 2 via a motor fixing / dustproof cover 17, and a ball screw nut 21b rotates. A slider 13 is disposed and fixed to the ball screw nut 21b via a ball bush 52b, and the slider 13 is guided by the shaft 52a and moves in a linear motion.

[0022] The connections between both ends of the slider 13 and bellows A15a and B15b are secured around the entire circumference by a packing 43 interposed between the bellows fixing plate 42 and the bellows end face plate 41, similar to the connections in the dustproof linear actuator 1, thus providing a dustproof and waterproof structure. Similarly, the connection between the end plate A11 and bellows A15a is secured via an adapter packing A44. The connection between bellows A15b and end plate B12 is also secured around the entire circumference by a packing 43 and a bellows end face plate 42 that presses and secures it to the end plate 11B, thus providing a dustproof and waterproof structure.

[0023] Figure 3 is a front view of the dustproof linear actuator 3. The dustproof linear actuator 3 is a commercially available linear actuator to which a base plate 19 is attached to the bottom surfaces of end plates A11 and B12, and bellows are connected to it. For example, in the case of a commercially available linear actuator in which the guide rail is integrated with the housing, the base plate 19 is fixed to the bottom surface of the actuator unit, and end plates A11 and B12 are fixed to both ends of it. The connection between both ends of the slider 13 and bellows A15a and B15b, and the connection between end plates A11 and B12 and bellows are performed in accordance with the connection method of dustproof linear actuators 1 and 2 described above, thereby creating a dustproof linear actuator. By attaching the base plate 19, the rigidity of the dustproof linear actuator is also improved, making it easier to ensure accuracy and dust resistance. On the other hand, the problems of increased weight and cost remain.

[0024] Figure 4(a) is a front view of a dustproof linear actuator 4, which is an embodiment of the present invention. A bellows A85a connects from the end plate A61 to one end of the top slide plate 65, covering the entire circumference between them. A bellows B85b connects from the other end of the top slide plate 65 to the end plate B62, covering the entire circumference between them. The dustproof linear actuator 4 is a commercially available linear actuator with a dustproof structure.

[0025] Figure 4(b) is a plan view of a dustproof linear actuator 4, which is an embodiment of the present invention. Similar to the front view, bellows A85a connect from end plate A61 to one end of top slide plate 65 and cover the space between them. Also, bellows B85b connect from the other end of top slide plate 65 to end plate B62 and cover the space between them.

[0026] Figure 4(c) is a view of the dustproof linear actuator 4 shown in Figure 4(a) via arrow AA. The part shown by the thick line in Figure 4(c) is a commercially available linear actuator 5. The commercially available linear actuator 5 consists of a ball screw shaft 71a, a ball screw nut 71b that screws onto the ball screw shaft 71a, and a slider 70 connected to the ball screw nut 71b. Even if the ball screw nut 71b rotates, the slider 70 does not rotate because it is supported via a ball bearing. The slider 70 is supported by a guide rail 72a provided on the stepped portion of the U-shaped housing 80, and a guide slider 72b positioned on the guide rail 72a, and moves linearly while extending and contracting bellows A85a and B85b as the ball screw shaft 71a rotates.

[0027] The top slide plate 65 is fixed to the slider 70 and is integrally configured with the side slide plates A67A, B67B and bottom slide plate 66, so it moves linearly as an integral part of the linear movement of the slider 70.

[0028] Figure 4(d) is a view of a dustproof linear actuator 4, an embodiment of the present invention, as seen from the BB arrow. An end plate A61 is shown on the outermost periphery, a bellows A85a is shown inside it, an actuator end plate 82 is shown inside that, and a bottom plate 63 is shown below the actuator end plate 82.

[0029] Figure 4(e) is a view of a dustproof linear actuator 4, an embodiment of the present invention, as seen from the JJ arrow. End plates A61 and B62 are provided at both ends, and the structure is such that the entire circumference in the circumferential direction is covered by a bellows 15a from end plate A61 to one end of the top slide plate 65. Furthermore, the structure is such that the entire circumference in the circumferential direction is covered by a bellows 15b from end plate B62 to the other end of the top slide plate 65.

[0030] Inside the bellows 15a and 15b, the drive motor 86, coupling 88, actuator input side plate 81, and actuator end plate 82 are visible. Between the actuator input side plate 81 and the actuator end plate 82, the guide rail 72a and ball screw shaft 71a are visible. To the left of the center, the slider 70 to which the top slide plate 65 is connected, the ball screw nut 71b, and below that, the bottom plate 63 are visible. [Explanation of Symbols]

[0031] 1. Dustproof linear actuator (heavy-duty transport specification) 2. Dustproof linear actuator (light load transport specification) 3. Dustproof linear actuator (with base plate) 4. Dustproof linear actuator (actuator with guide rail) 5. Commercially available linear actuators 11 End Plate A 12 End Plate B 13 Slider 15a Bellows A 15b Bellows B 16. Drive motor 17. Electric motor fixing / dustproof cover 18 Fittings 19 Base Plate 21a Ball screw shaft 21b Ball screw nut 22a Ball spline shaft 22b Ball spline nut 31 Flowpath 32 filters 41 Bellows end plate 42 Bellows fixing plate 43 Packing 44 Adapter packing A 45 Adapter packing A 52a shaft 52b Ball bushing 61 End Plate A 62 End Plate B 63 Bottom Plate 65 Top slide plate 66 Bottom slide plate 67a Side slide plate A 67b Side Slide Plate B 70 Slider 71a Ball screw shaft 71b Ball screw nut 72a Guide rail 72b Guide Slider 80 cabinets 81 Actuator input side plate 82 Actuator End Plate 85a Bellows A 85b Bellows B 86. Motor for drive 88 Fittings

Claims

1. A dustproof structure for a linear actuator in which a rectangular movable body having a mouth-shaped end face moves linearly, functionally connected to a ball screw shaft via a ball nut that screws onto the ball screw shaft by the rotation of the ball screw shaft located between a first end plate and a second end plate, A first bellows that covers the entire circumference from one end face of the moving body to the first end plate, and a sealing material that seals the one end face and the end face of the first bellows, A second bellows that covers the entire circumference from the other end face of the moving body to the second end plate, and a sealing material that seals the other end face and the end face of the second bellows, A dustproof structure for a linear actuator, characterized by comprising a motor fixing and dustproof cover provided on the outside of the first end plate, which covers the entire circumference from the coupling-side end face of the drive motor connected by a coupling to one end of the ball screw shaft extending from the through hole of the first end plate to the first end plate, fixing the drive motor to the first end plate, and preventing dust from entering the through hole.

2. The dustproof structure for a linear actuator according to claim 1, characterized in that the second end plate is provided with a vent hole equipped with a filter for filtering dust from the outside, or a vent hole equipped with a filter for removing internal air through the filter.

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