Waterproof structure and robot

Abstract

The waterproof structure (1) includes: an extension shaft (2) which is coaxially disposed on the upper side of the ball screw spline shaft (14) extending in the vertical direction; a cylindrical cover member (4) which covers the extension shaft (2) and the ball screw spline shaft (14) and is telescopic along the long axis (J3) of the extension shaft (2); and a rotatable connection (3) which connects the ball screw spline shaft (14) and the extension shaft (2) in a manner that allows them to rotate relative to each other around the long axis (J3), with the upper end of the cover member (4) fixed to the upper end of the extension shaft (2).

Description

Technical Field

[0001] This invention relates to waterproof structures and robots. Background Technology

[0002] Conventionally, waterproof structures for horizontal multi-joint (SCARA) robots have used a serpentine-shaped cover member that covers the ball screw spline (BS) shaft and is extendable along the length of the BS shaft (see, for example, Patent Documents 1-3). In Patent Documents 1-3, the extension shaft is connected to the upper end of the BS shaft, and the cover member covers both the BS shaft and the extension shaft.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-228733

[0006] Patent Document 2: Japanese Patent No. 5444858

[0007] Patent Document 3: Japanese Patent No. 5792988 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] The BS shaft and the extension shaft rotate integrally around the long axis of the BS shaft. In Patent Documents 1-3, to prevent the cover component from twisting due to the rotation of the BS shaft, the upper end of the cover component is mounted to the upper end of the extension shaft via a bearing. In this case, a rotary seal is provided to seal the upper end of the extension shaft and the upper end of the cover component for dust and water protection of the bearing. When the rotary seal is an oil seal, a special specification oil seal with low sliding resistance is required to prevent the cover component from twisting, increasing the cost. When the rotary seal is a labyrinth seal, its waterproof performance is inferior to that of an oil seal.

[0010] Solution for solving the problem

[0011] One aspect of the present invention is a waterproof structure comprising: an extension shaft coaxially disposed on the upper side of a ball screw spline shaft extending in a vertical direction; a cylindrical cover member covering the extension shaft and the ball screw spline shaft, and capable of extending and retracting along the long axis of the extension shaft; and a rotatable connecting portion connecting the ball screw spline shaft and the extension shaft in a manner capable of relative rotation about the long axis, wherein the upper end of the cover member is fixed to the upper end of the extension shaft. Attached Figure Description

[0012] Figure 1 This is a side view of a robot according to one implementation method.

[0013] Figure 2 yes Figure 1 The front view of the robot.

[0014] Figure 3 This is a sectional view showing the composition of the waterproof structure, along... Figure 2 A partial longitudinal sectional view of the robot along line A-A.

[0015] Figure 4 This is a three-dimensional view of the upper part of the waterproof structure. Detailed Implementation

[0016] Hereinafter, a waterproof structure 1 and a robot 10 according to one embodiment will be described with reference to the accompanying drawings.

[0017] like Figure 1 as well as Figure 2 As shown, robot 10 is a horizontal multi-joint robot with a base 11, a first arm 12, a second arm 13, and a ball screw spline (BS) axis 14.

[0018] The base 11 is fixed to the mounting surface.

[0019] One end of the first arm 12 is supported on the base 11 in a manner that allows it to rotate about a vertical first axis J1, and the first arm 12 is rotatable relative to the base 11 in the horizontal direction.

[0020] One end of the second arm 13 is supported on the other end of the first arm 12 in a manner that allows it to rotate about a vertical second axis J2, and the second arm 13 is capable of rotating in the horizontal direction relative to the first arm 12.

[0021] The BS axis 14 is supported at the other end of the second arm 13 in a manner that allows it to move linearly in the vertical direction along its major axis, the third axis J3, and to rotate about the third axis J3. A hand or other tool (not shown) is connected to the lower end of the BS axis 14. The BS axis 14 is a hollow cylindrical tube with an opening at least at the upper end, allowing wiring or other wires for tools to pass through its interior.

[0022] Thus, the BS shaft 14, extending vertically, passes through the second arm 13 and moves vertically relative to the second arm 13. Therefore, the upper wall of the cover of the second arm 13 has an opening for the BS shaft 14 to pass through (not shown). The robot 10 also has a waterproof structure 1 for preventing water from entering the interior of the second arm 13 through the opening.

[0023] like Figure 3As shown, the waterproof structure 1 includes: an extension shaft (e.g., a first shaft) 2, which is coaxially disposed on the upper side of the BS shaft (e.g., a second shaft) 14; a rotatable connection 3, which connects the extension shaft 2 to the BS shaft 14; and a cylindrical cover member 4, which covers the extension shaft 2 and the BS shaft 14.

[0024] When the BS shaft 14 descends to its lowest position, its upper end descends to near the upper surface of the cover of the second arm 13. An extension shaft 2, connected to the upper end of the BS shaft 14, ensures a distance for configuring the cover component 4 between the upper surface of the cover of the second arm 13 and the upper end of the extension shaft 2. The extension shaft 2 is a hollow cylindrical tube open at both ends, and its interior communicates with the interior of the BS shaft 14.

[0025] A rotary connection 3 is disposed at the connection between the BS shaft 14 and the extension shaft 2, connecting the BS shaft 14 and the extension shaft 2 in a manner that allows them to rotate relative to each other around a third axis J3. Specifically, the rotary connection 3 includes: a cylindrical bearing bracket 5 disposed radially outward at the lower end of the extension shaft 2 and fixed to the BS shaft 14; and a bearing 6 disposed between the outer peripheral surface of the extension shaft 2 and the inner peripheral surface of the bearing bracket 5.

[0026] The bearing bracket 5 has: a cylindrical first component 51 disposed radially outward of the upper end of the BS shaft 14 and fixed to the upper end of the BS shaft 14; and a cylindrical second component 52 disposed radially outward of the lower end of the extension shaft 2 and fixed to the first component 51.

[0027] For example, the first component 51 is a cylindrical component with a slit that cuts off the first component 51 circumferentially. The first component 51 is fixed to the outer circumferential surface of the upper end of the BS shaft 14 by tightening a bolt 7a that passes through the slit. The first component 51 and the second component 52 are fixed to each other by bolts 7b that are inserted into the first component 51 and the second component 52 along their length.

[0028] The second component 52 has an inner diameter larger than the outer diameter of the extension shaft 2. A bearing 6 is disposed between the outer circumferential surface of the extension shaft 2 and the inner circumferential surface of the second component 52. The inner ring of the bearing 6 is fixed to the extension shaft 2, and the outer ring of the bearing 6 is fixed to the second component 52. The extension shaft 2 and the bearing bracket 5 are connected in a rotatable manner using the bearing 6.

[0029] The cover component 4 is belly-shaped and can extend and retract along its length. The cover component 4 extends vertically from the upper end of the extension shaft 2 to the upper surface of the cover of the second arm 13, and covers the extension shaft 2 and the protruding portion of the BS shaft 14 that protrudes upward from the second arm 13. A swivel connection 3 is disposed in the cylindrical space S between the shafts 2 and 14 and the cover component 4. The cover component 4 can also have a structure other than a belly shape, as long as it can extend and retract along its length while maintaining the closure of the space S.

[0030] The lower end of the cover component 4 is fixed to the upper surface of the cover of the second arm 13, and the hole through which the BS shaft 14 passes is disposed on the inner side of the cover component 4. The cover component 4, which covers the hole, prevents liquid from entering the interior of the second arm 13 through the hole.

[0031] The upper end of the cover component 4 is fixed to the upper end of the extension shaft 2. Specifically, a ring-shaped flange portion 2a is provided at the upper end of the extension shaft 2, and a ring-shaped flange portion 4a is provided at the upper end of the cover component 4. The flange portion 2a is positioned above the flange portion 4a, and the flange portion 2a and the flange portion 4a are fixed to each other by bolts 7c.

[0032] To improve the airtightness of space S and enhance the waterproof performance of waterproof structure 1, waterproof structure 1 also includes sealing element 81, sealing element 82, and labyrinth seal 9.

[0033] The seal (first fixed seal) 81 is used to seal between the upper end of the extension shaft 2 and the upper end of the cover component 4, preventing liquid from entering the space S from the outside of the waterproof structure 1.

[0034] Specifically, the seal 81 is disposed between the lower surface of the flange 2a and the upper surface of the flange 4a. Since the flange 2a and the flange 4a are fixed parts that are stationary to each other, a gasket or other fixed sealing element is used as the seal 81.

[0035] The seal (second fixed seal) 82 is used to seal between the BS shaft 14 and the bearing bracket 5, preventing liquid from entering the space S from the inside of the shafts 2 and 14.

[0036] Specifically, a ring-shaped protrusion 52c is provided on the lower end face of the second component 52, which fits into the interior of the first component 51. The lower end face of the protrusion 52c is opposite to the upper end face of the BS shaft 14. A seal 82 is disposed between the lower end face of the protrusion 52c and the upper end face of the BS shaft 14. Since the BS shaft 14 and the bearing bracket 5 are fixed parts that are stationary to each other, a fixed seal such as an O-ring is used as the seal 82.

[0037] The labyrinth seal 9 is formed by gaps 9a and 9b between the outer surface of the lower end of the extension shaft 2 and the inner surface of the bearing support 5, and is used to prevent liquid from entering the bearing 6 and the space S from the inside of the extension shaft 2.

[0038] Specifically, the inner surface of the second component 52 has: an annular lower wall 52a facing the annular lower end face of the extension shaft 2; and a cylindrical side wall 52b rising upward from the outer edge of the lower wall 52a. A horizontal annular gap 9a is provided between the lower end face of the extension shaft 2 and the lower wall 52a, and a vertical cylindrical gap 9b is provided between the outer peripheral surface of the extension shaft 2 and the side wall 52b.

[0039] Bearing 6 is positioned higher than labyrinth seal 9. Although liquid that has infiltrated the interior of extension shaft 2 can enter gap 9a horizontally, gravity prevents it from rising in gap 9b. Therefore, bearing 6 is positioned above gap 9b to prevent liquid from entering.

[0040] The functions of the waterproof structure 1 and the robot 10 will be explained below.

[0041] When robot 10 is in operation, rotational force is transmitted from a motor (not shown) within the second arm 13 to the BS axis 14, causing the BS axis 14 to rotate around the third axis J3 while simultaneously rising and falling along the third axis J3. The extension shaft 2 also rises and falls along with the BS axis 14. The cover component 4 extends and retracts due to the rising and falling of the upper end of the extension shaft 2. This cover component 4 prevents liquid from entering the interior of the second arm 13 from the outside.

[0042] Since the BS shaft 14 and the extension shaft 2 are connected in a rotatable manner via the rotating connection 3, only the BS shaft 14 rotates around the third axis J3, while the extension shaft 2 and the cover component 4 remain stationary relative to each other. Therefore, to seal the upper end of the extension shaft 2 and the upper end of the cover component 4, expensive parts like oil seals are unnecessary; a cheaper fixing seal 81, such as a gasket, can be used to seal the upper end of the extension shaft 2 and the upper end of the cover component 4. This achieves high waterproof performance and reduces costs for the waterproof structure 1.

[0043] Furthermore, an inexpensive fixing seal 82, such as an O-ring, is used to seal the space between the BS shaft 14, which serves as the fixing part, and the bearing bracket 5. This allows for further improvement in the waterproof performance of the waterproof structure 1 without increasing costs.

[0044] Furthermore, a labyrinth seal 9 is used in the seal between the lower end of the extension shaft 2, which is a rotating part, and the bearing support 5. When a contact-type rotary seal, such as an oil seal, is used to seal between the lower end of the extension shaft 2 and the bearing support 5, a torsional force around the third axis J3 generated by the sliding resistance of the rotary seal may be applied to the cover member 4. According to this embodiment, by using a non-contact labyrinth seal 9, the torsional force applied to the cover member 4 can be reduced, and the life of the cover member 4 can be extended.

[0045] In addition, by placing the bearing 6 on the upper side of the labyrinth seal 9, liquid intrusion into the bearing 6 can be reliably prevented, and high waterproof performance of the rotating part can be achieved with an inexpensive structure.

[0046] In this embodiment, such as Figure 3 as well as Figure 4 As shown, the extension shaft 2 may also have a fixing part 2b for fixing the line body 16 to the upper end of the extension shaft 2.

[0047] For example, the fixing part 2b is a threaded hole that opens on the upper end face of the extension shaft 2. By tightening the bolt 7d into the threaded hole 2b, the fixing part 15 is fixed to the upper end face of the extension shaft 2. The line body 16 passes through the shafts 2 and 14 and is pulled out from the upper end face of the extension shaft 2, and is fixed relative to the upper end of the extension shaft 2 by the fixing part 15.

[0048] Since the extension axis 2 does not rotate around the third axis J3, it is possible to fix the line body 16 relative to the extension axis 2 while preventing the line body 16 from twisting.

[0049] In this embodiment, the waterproof structure 1 is provided with a seal 81 that seals the upper end of the extension shaft 2 and the upper end of the cover member 4. However, the upper end of the extension shaft 2 and the upper end of the cover member 4 can also be sealed by means other than the seal 81. Since the upper end of the extension shaft 2 and the upper end of the cover member 4 are fixed parts, various means other than fixed seals such as gaskets can be used to seal the upper end of the extension shaft 2 and the upper end of the cover member 4.

[0050] In this embodiment, the extension shaft 2 is set to be a hollow tube with an open upper end face, but the extension shaft 2 can also be a hollow shaft with a closed upper end face or a solid shaft. In this case, since liquid will not invade the interior of the extension shaft 2, the seal 82 and the labyrinth seal 9 can be omitted.

[0051] In this embodiment, robot 10 is set to be a horizontal multi-joint robot, but the robot using waterproof structure 1 is not limited to a horizontal multi-joint robot, and can also be any robot with a BS axis extending in the vertical direction.

[0052] In this embodiment, the waterproof structure 1 is provided with an extension shaft 2 connected to the BS shaft 14. However, the waterproof structure of the present invention can be applied to any structure having two shafts arranged in series on the same axis and rotating relative to each other. That is, the waterproof structure may also include: a cover member that covers the first shaft and the second shaft arranged along the long axis direction of the first shaft, and is extendable and retractable in the long axis direction; and a rotatable connecting portion that connects the first shaft and the second shaft in a manner that allows them to rotate relative to each other about the long axis. Preferably, the waterproof structure also includes a seal that seals at least the fixed portion. For example, the seal may be used to seal at least one of the following: between the first shaft and the cover member, and between the second shaft and the rotatable connecting portion.

[0053] The embodiments of the present invention have been described in detail, but the present invention is not limited to the various embodiments described above. Various additions, substitutions, modifications, and partial deletions can be made to these embodiments without departing from the spirit and intent of the invention, or without departing from the content of the claims and their equivalents. For example, in the embodiments described above, the order of each action and the order of each process are exemplary and not limited thereto. Furthermore, the same applies to the use of numerical values ​​or formulas in the description of the embodiments.

[0054] Explanation of reference numerals in the attached figures:

[0055] 1: Waterproof structure

[0056] 2: Extension shaft

[0057] 2b: Fixing part

[0058] 3: Rotary connecting part

[0059] 4: Cover components

[0060] 5: Bearing bracket

[0061] 6: Bearings

[0062] 81: First fixed seal

[0063] 82: Second fixed seal

[0064] 9: Maze Sealing

[0065] 9a, 9b: Gap

[0066] 10: Robot

[0067] 14: Ball screw spline shaft

[0068] 15: Fixed components

[0069] 16: Linear Font

[0070] J1, J2, J3: Axis

Claims

1. A waterproof structure, characterized in that, have: An extension shaft is coaxially disposed on the upper side of the ball screw spline shaft, which extends in the vertical direction. A cylindrical cover component that covers the extension shaft and the ball screw spline shaft, and is capable of extending and retracting along the long axis of the extension shaft; as well as A rotary connector connects the ball screw spline shaft and the extension shaft in a manner that allows them to rotate relative to each other about the long axis. The upper end of the cover component is fixed to the upper end of the extension shaft. The lower end of the cover component is fixed to a component that supports the ball screw spline shaft in a manner that allows it to rotate about the long axis. The cover component is not fixed to the ball screw spline shaft, and the ball screw spline shaft is rotatable relative to the cover component about the long axis.

2. The waterproof structure according to claim 1, characterized in that, The waterproof structure includes a first fixed seal that seals the upper end of the extension shaft and the upper end of the cover component.

3. The waterproof structure according to claim 1 or 2, characterized in that, The rotary connecting part includes: A cylindrical bearing support is disposed radially outward at the lower end of the extension shaft and fixed to the ball screw spline shaft; and A bearing is disposed between the outer peripheral surface of the extension shaft and the inner peripheral surface of the bearing support.

4. The waterproof structure according to claim 3, characterized in that, The waterproof structure has a labyrinth seal formed by the gap between the outer surface of the lower end of the extension shaft and the inner surface of the bearing bracket. The bearing is positioned higher than the labyrinth seal.

5. The waterproof structure according to claim 3, characterized in that, The waterproof structure includes a second fixed seal that seals the space between the ball screw spline shaft and the bearing bracket.

6. The waterproof structure according to claim 1 or 2, characterized in that, The extension shaft has a fixing part for fixing the line body to the upper end of the extension shaft.

7. A robot, characterized in that, The robot has a waterproof structure as described in any one of claims 1 to 6.

8. A waterproof structure, characterized in that, have: A cover component that covers a first axis and a second axis disposed along the long axis of the first axis, and is extendable and retractable along the long axis; and A rotatable connector that connects the first shaft and the second shaft in a manner that allows them to rotate relative to each other about the long axis. One end of the cover component is fixed to one end of the first shaft on the side opposite to the second shaft in the long axis direction. The other end of the cover component is fixed to a component that supports the second shaft in a manner that allows it to rotate about the long axis. The cover component is not fixed to the second axis, and the second axis is capable of rotating about the long axis relative to the cover component. At least one of the following is sealed: between the first shaft and the cover component, and between the second shaft and the rotary connection.

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