JP2011031345A - End cover of robot arm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the runoff of water and to prevent a cloth from being hooked on the head of a fixing bolt when the outer surface of an end cover is wiped with the cloth, in the end cover fixed on a vertically rotating arm. <P>SOLUTION: Groove-shaped hidden recessed portions 12 are formed at four edge corners of a cover body 9 with a square container shape. Upper and lower circumferential side surfaces 10a, 10b of the cover body 9 are formed in circular arcuate projected surfaces with respect to the circumferential direction. A closed end surface 11 is formed substantially in a dome shape. This improves runoff of water from the outer surface of the cover body 9. Two wall surfaces 14, 15 of the groove-shaped hidden recessed portion 12 are inclined. A through hole 18 for the bolt is on a diagonal line on a mounting seat surface 13. Besides, in regard to dimensions in the direction toward the two wall surfaces 14, 15 on the mounting seat surface 13, the distances between the hexagonal head of the bolt and the two wall surfaces 14, 15 are equal to or more than the height of the hexagonal head including a washer. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an end cover that covers one end of an arm of a robot.

  Robots used in the field of manufacturing foods and medicines are cleaned with chemicals or water by the user in order to maintain cleanliness. After washing with water, leave it as it is to let it drain and let it dry naturally, or wipe it off with a cloth and let it dry naturally.

  By the way, the arm constituting the robot is hollow, and has a frame structure having an opening for incorporating various parts into the hollow. For this reason, after incorporating various components inside, the arm is covered with a cover whose outer surface is painted. This arm cover is fixed to the arm by a bolt. Among such arm covers, there is an end cover that covers the end of the arm, and the present invention is directed to this end cover.

  In Patent Document 1, in a robot used at a work site where food materials are handled, conventionally, when a robot surface member and a robot internal member are combined, a hexagon socket head bolt is used and a bolt head is formed on the robot surface member. In this case, when the liquid material enters the counterbore hole or the hexagonal hole in the head of the bolt, it is difficult to remove the liquid material. In order to solve this problem, hexagon head bolts are used in place of the hexagon socket head bolts, and foreign matter accumulation around the bolt heads is prevented by using an inclined raised portion around the bolt holes on the outer surface of the robot surface member. It is described that the cleaning is facilitated.

Japanese Patent Laid-Open No. 11-33974

  If a robot used in the field of food or chemicals is washed with water, etc., after washing, it is important to take into account that it will be naturally watered and dried, or wiped with a cloth and dried. It is preferable to adopt a configuration in which water does not remain on the outer surface of the part cover. However, if the four peripheral side surfaces of the square container-shaped end cover are flat, if the arm stops in a posture where the upper side surface of the four peripheral side surfaces is horizontal or nearly horizontal, the cleaning is performed as it is. , Natural water cannot be drained from the flat upper surface, and water remains.

  Further, for the maintenance of the robot, it is necessary to expose the head of the bolt for fixing the end cover to the outside. However, as disclosed in Patent Document 1, when the head of the hexagon head bolt protrudes from the outer surface of the robot surface member, the cloth becomes the head of the bolt when the outer surface of the robot is wiped with the cloth. If you get caught in the thread, lint will remain and it will be unsanitary.

  Therefore, it is necessary to devise so that the head of the bolt that fixes the end cover to the arm does not protrude from the outer surface of the cover. However, to prevent the bolt head from protruding from the outer surface of the cover, the bolt head must be housed in a counterbore, but the bolt head must be in the counterbore. If stored, it will be difficult to remove the water that has entered the counterbore when washed with water or the like.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide good drainage from the outer surface of an end cover that covers one end of an arm that pivots up and down. Even if the head of the bolt for fixing to the robot is exposed to the outside, the end cover of the robot arm that does not get caught in the head of the bolt when the outer surface of the end cover is wiped with a cloth Is to provide.

  According to the first aspect of the present invention, in the peripheral surface of the container-shaped cover body whose one end is open and the other end is closed, the peripheral surface is divided into a plurality of surfaces in the circumferential direction. A groove-like concavity extending from the open end side of the one end of the cover body toward the closed end of the other end is provided by recessing in an L shape inwardly. And since the surface located at least up and down among the plurality of peripheral surfaces defined by the groove-like hidden recesses of the cover body is formed so as to form an arc convex shape with respect to the circumferential direction, the arm rotating in the vertical direction Whatever rotation angle posture is taken, there is no portion that becomes a horizontal plane on the plurality of peripheral surfaces of the cover main body, and it becomes an inclined surface, so that it is excellent in drainage.

  Further, the groove-like hidden recess is located on the opening end side of the cover body, and a mounting seat surface for the head of the bolt, and two wall surfaces extending from two adjacent sides of the mounting seat surface toward the closed end of the cover body The two adjacent wall surfaces are inclined so as to widen the gap between the groove-shaped hidden recesses from the corners formed by the intersection of the two wall surfaces toward the peripheral surface, and the mounting seat surface Since the slope of the groove-like concavity is widened from the cover body to the closed end of the cover body, the water that has entered the inside of the groove-like concavity will naturally form the groove-like concavity, regardless of the posture of the arm. Flowing out of. For this reason, the water repellency in the groove-like concavity is excellent.

Furthermore, when the outer surface of the cover body is wiped quickly with a cloth, the cloth moves quickly, so the outer edge of the installation seat surface (around the open side to the outside), the two wall surfaces and the periphery of the cover body It is harder to enter inside the virtual surface including the three ridges intersecting the surface. According to the first aspect of the present invention, since the through hole formed in the mounting seat surface exists on the diagonal line of the mounting seat surface or deeper than the diagonal line in the groove-like concavity, the head of the bolt passed through the through hole. Even if the portion is exposed on the mounting seat surface, the head of the bolt is concealed in the groove-like hidden recess, and the outer edge of the mounting seat surface, the two wall surfaces, and the peripheral surface Therefore, it is possible to prevent the cloth from being caught on the head of the bolt as much as possible.
Moreover, the depth of the mounting seat surface is set such that the distance between the head of the bolt passed through the through hole and the two wall surfaces of the groove-like hidden recess is equal to or higher than the height of the bolt head. The cloth can be easily put between the head of the bolt and the two wall surfaces of the groove-like concavity, and the water remaining behind the installation seat can be easily wiped off.

  The cover main body may be formed in a rectangular container shape as in the second aspect of the invention, and the groove-like hidden recesses may be formed on the four ridges on the peripheral surface. On the premise of the cover main body of claim 2, as in the invention of claim 3, at least the upper and lower surfaces of the peripheral surface of the cover main body are gradually narrowed from the open end to the closed end. You may comprise so that it may become inclined.

  By the way, when cleaning the robot, the arm is usually stopped in a posture that is easy to clean, such as horizontal, slightly downward or slightly upward. As long as the arm assumes this posture, even if the closed end surface of the cover body is a flat surface, the closed end surface has a vertical surface or an inclined surface, so that it has excellent drainage. In this regard, in the invention of claim 4, the closed end surface of the cover body is formed in an arcuate surface that protrudes outward, so that the arm can be in any posture including horizontal, slightly downward or slightly upward. Even if it takes, there is no part which becomes a horizontal plane about the whole outer surface of a cover main body including a closed end face, and it can aim at the further improvement of water drainage.

The end cover in one Embodiment of this invention is shown, (a) is a rear view, (b) is a side view, (c) is a top view It shows a groove-like hidden recess at one ridge of the end cover, (a) is a rear view cut along line II in (b), and (b) is II-II in (a). The side view which cuts and shows along a line, (c) is the side view which shows the cloth in the case of wiping so that it may straddle on the groove-like concavity with cloth. Perspective view of end cover attached to robot arm Robot perspective view The perspective view which shows the state which wipes the outer surface of an edge part cover so that it may straddle over a groove-like concavity with cloth. The perspective view which shows the state which wipes the back of a bolt head with cloth The perspective view of the end cover in other embodiments of the present invention. It shows an end cover, (a) is a rear view, (b) is a side view. Rear view of grooved concavity

(One embodiment)
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 4 shows an industrial robot. This industrial robot is composed of, for example, a 6-axis vertical articulated robot, and includes a base 1, a shoulder portion 2 supported on the base 1 so as to be rotatable in the horizontal direction around the J1 axis, and the shoulder portion. 2 is supported by the lower arm 3 so as to be rotatable in the vertical direction about the J2 axis, and the first upper arm 4 is supported by the lower arm 3 so as to be rotatable in the vertical direction around the J3 axis. A second upper arm 5 supported by the upper arm 4 so as to be twisted and rotated about the J4 axis, and a wrist 6 supported by the second upper arm 5 so as to be rotatable in the vertical direction about the J5 axis. And a flange 7 that is supported by the wrist 6 so as to be rotatable about the J6 axis.
The base 1, the shoulder portion 2, the lower arm 3, the first upper arm 4, the second upper arm 5, the wrist 6 and the flange 7 function as a robot arm. However, an end effector (hand) is attached.

The arms 1 to 6 except for the flange 7 made of a disk are hollow and have a frame structure in which an opening is formed in a required portion. Each of the arms 1 to 6 is attached with a motor, a speed reducer, or the like inside the hollow through the opening, or accommodates a power line or a signal line, and then attached with an aluminum arm cover to close the opening. It is out.
Since the industrial robot of this embodiment is relatively small and can be used in various fields, the arm cover should be drained in consideration of being washed with water when used in food or pharmaceutical manufacturing sites. The shape and structure that make the natural is adopted.

  By the way, among the arm covers, there is an end cover that is put on one end of the arm and fixed by a bolt. In the industrial robot shown in FIG. 4, as shown in FIG. 3, an end cover 8 is put on one end of the first upper arm 4, that is, the rear end. The end cover 8 also has a shape and structure that allows water to drain naturally. The front, rear, left, right, top and bottom of the first upper arm 4 and the end cover 8 are viewed when the robot is viewed from the flange 7 side with the first upper arm 4 in a substantially horizontal state. In the following description, the front side is the front, the opposite side is the rear, the left hand side is the left, the right hand side is the right, and the top and bottom are the top and bottom.

  The end cover 8 is made of aluminum formed by a casting mold, and the outer surface is painted. The end cover 8 is mainly composed of, for example, a rectangular container-like cover main body 9, and the cover main body 9 is open at one end and closed at the other end, and the open end surface of the one end serves as the first upper arm 4. It is set as the attachment surface 9a. The cover main body 9 is a part of which the peripheral surface is divided into the upper, lower, left and right peripheral side surfaces 10a to 10d, that is, the four ridges leave the opening end side of one end (front end) by a predetermined thickness. A groove-like hidden recess 12 is formed by recessing in an L shape toward the direction.

  As shown in FIG. 1, among the four peripheral side surfaces 10 a to 10 d of the cover body 9, the upper and lower peripheral side surfaces 10 a and 10 b are between the peripheral side surfaces 10 a and 10 b from the open end at one end to the closed end at the other end. It is formed in an inclined shape so as to gradually narrow, and is configured such that the shape seen from the left and right peripheral side surfaces 10c and 10d becomes a trapezoid. Further, the upper and lower peripheral side surfaces 10a and 10b are curved so as to form a gentle arc surface that protrudes outward along the circumferential direction (left-right direction).

On the other hand, the left and right peripheral side surfaces 10c and 10d have flat surfaces whose upper and lower central portions are parallel to each other, and the upper and lower side portions of the flat surface portion are gently convex outward along the circumferential direction (vertical direction). It is curved so as to form a circular arc surface.
Further, the closed end surface 11 of the cover body 9 is formed in a curved shape so as to form an arc surface protruding outward from the center toward the four circumferential side surfaces 10a to 10d, and has a dome shape as a whole.
As shown in FIG. 2, the groove-like hidden recess 12 is located on the opening end side of the cover body 9 and is parallel to the opening end surface (mounting surface 9 a), and the periphery of the mounting seat surface 13. The groove-like concavity 12 includes two wall surfaces extending from two adjacent sides on the back side toward the closed end side of the cover body 9, that is, a substantially vertical vertical wall surface 14 and a substantially horizontal horizontal wall surface 15. The corner where the horizontal wall 15 intersects is formed in a concave arcuate surface 16.

The vertical wall surface 14 and the horizontal wall surface 15 are installed so as to widen the outward opening of the groove-like hidden recess 12 toward the peripheral side surfaces 10a to 10d of the cover body 9, that is, as shown in FIG. When a vertical line V and a horizontal line H passing through the intersection P1 of the vertical wall surface 14 and the horizontal wall surface 15 on the seat surface 13 are assumed, and the vertical line V and the horizontal line H are assumed to be around the groove-like hidden recess 12, It inclines so that it may leave | separate gradually from the groove-shaped hidden recessed part 12 toward the side surfaces 10a-10d.
The angle formed between the vertical wall surface 14 and the horizontal wall surface 15 is an obtuse angle. The horizontal wall surface 15 is inclined downward toward the left peripheral side surface 10c and the right peripheral side surface 10d, and the side of the upper groove-like concavity 12 is formed. The wall surface 15 is inclined downward toward the closed end side, and the lateral wall surface 15 of the lower groove-like concavity 12 is inclined upward toward the closed end side.

  Further, the vertical wall surface 14 and the horizontal wall surface 15 are arranged so that the depth increases from the mounting seat surface 13 toward the closed end side of the cover main body 9, that is, as shown in FIG. A vertical plane Fv perpendicular to 13 and a horizontal plane Fh perpendicular to the installation seat surface 13 including the horizontal line H is assumed, and the vertical plane Fv and horizontal plane Fh are located on the closed end side of the cover body 9 from two adjacent sides of the installation seat surface 13. Assuming that the two wall surfaces extend in the direction from the open end of the cover body 9 toward the closed end, the cover body 9 is inclined so as to gradually move away from the groove-like hidden recess 12.

  The mounting seat surface 13 has a through hole 18 through which a bolt 17 for fixing the cover body 9 to the first upper arm 4 is passed. The bolt 17 is not a bolt having a hexagon hole in which water accumulates but a hexagon bolt without such a hole. The through hole 18 is formed at the intersection P2 between the mounting seat surface 13 and the end of the vertical wall surface 14 on the open side of the groove-like hidden recess 12 and the intersection P3 between the mounting seat surface 13 and the end of the lateral wall surface 15. Assuming that the diagonal line L of the mounting seat surface 13 formed by connecting both intersections P2 and P3 is assumed, the diagonal line L is determined to exist on the diagonal line L.

  In this case, existence on the diagonal line L does not necessarily mean that the center of the through hole 18 is located on the diagonal line L, and somewhere in the through hole 18 (including the inner peripheral edge) is located on the diagonal line L. It should be. The formation position of the through hole 18 is determined within a range where somewhere in the through hole 18 is located on the diagonal line L. Of the periphery of the mounting seat surface 13, the periphery of the groove-like hidden recess 12 on the open side ( With respect to the direction toward the outer edge, the position is determined so that the hexagon head 17a of the bolt 17 does not protrude from the periphery on the open side. The through hole 18 is formed at a position where the bolt 17 is passed through the bolt 17 with a washer 19 in the direction toward the vertical wall surface 14, the horizontal wall surface 15 and the circular arc surface 16 of the mounting seat surface 13. When passing through the hole 18, the distance D between the hexagonal head (head) 17 a of the bolt 17 including the washer 19 and the vertical wall surface 14, the horizontal wall surface 15, and the arc surface 16 is such that the hexagonal head 17 a including the washer 19 The dimension is set to a height T or more.

A lamp 20 is attached to the left peripheral side surface 10c and the right peripheral side surface 10d of the cover body 9 to indicate when the robot is in operation.
In the industrial robot shown in FIG. 4, the end cover 8 mainly composed of the cover main body 9 as described above is put on the rear end portion of the first upper arm 4 and fixed by the bolt 17. The fixing structure by the bolts 17 will be described in detail. The mounting surface 9a of the cover body 9 is abutted against the mounting surface 4a (see FIG. 3) of the first upper arm 4, and the mounting seat surface 13 of the four groove-like hidden recesses 12 is placed. The mounting surface 9 a of the cover body 9 is inserted into the through hole 18 by inserting the bolt 17 with the washer 19 attached thereto and screwing it into a screw hole (not shown) formed in the mounting surface of the first upper arm 4. The first upper arm 4 is fastened and fixed.
At the time of attachment, the shape of the cover main body 9 of the present embodiment is symmetrical left and right and also vertically, so there is no problem even if the cover main body 9 is installed upside down, and there is no so-called directivity. It has become a thing.

  When an industrial robot having such an end cover 8 attached thereto is washed with water, it is naturally drained from the outer surface of the end cover 8. In order to explain this natural water drainage, first, in order to facilitate understanding, it is assumed that the first upper arm 4 is cleaned in a substantially horizontal posture. In this case, the four peripheral side surfaces 10a to 10d of the cover body 9 have a trapezoidal shape in which the upper peripheral side surface 10a and the lower peripheral side surface 10b gradually narrow from the opening end of the cover main body 9 toward the closed end side, and in the circumferential direction. Therefore, a portion that becomes a horizontal flat surface does not occur anywhere. For this reason, the water adhering to the upper peripheral side surface 10a flows from the open end side toward the closed end side and also flows in the left-right direction. The water that flows in the left-right direction along the upper peripheral side surface 10a enters the upper groove-like concavity 12, and is formed on the left peripheral side surface 10c, the right peripheral side surface 10d, and the lateral wall surface 15 that is inclined downward toward the closed end side. It flows out to the left peripheral side surface 10c, the right peripheral side surface 10 or the closed end surface 11 along the inclination.

  In particular, in the present embodiment, the upper peripheral side surface 10a and the lower peripheral side surface 10b form a trapezoidal shape that gradually narrows from the open end of the cover body 9 toward the closed end side, so that the first upper arm 4 is directed downward. When cleaning in a posture, unless the downward angle is increased to some extent, the upper peripheral side surface 10a is not inclined downward toward the front side, so that water attached to the upper peripheral side surface 10a flows forward, The opportunity to enter between the attachment surface 9a of the main body 9 and the attachment surface 4a of the first upper arm 4 can be minimized.

  Further, since the closed end face 11 has a dome shape that forms a circular arc shape from the center toward the four circumferential side faces 10a to 10d, there is no portion that becomes a horizontal plane. For this reason, water adhering to the closed end surface 11 or water flowing from the other surface to the closed end surface 11 flows downward along the circular arc surface of the closed end surface 11, and reaches the lower half of the closed end surface 11. Part of the water drops, and the remaining water is transferred to the lower peripheral surface 10b as it is.

  The left peripheral side surface 10c and the right peripheral side surface 10d are bent at the upper and lower portions, and the central portion in the vertical direction therebetween is a flat surface, but the first upper arm 4 rotates by itself up and down, For example, although it is also rotated up and down by the lower arm 3, it does not twist and rotate, so that the plane of the central portion in the vertical direction does not become a horizontal plane and is always a vertical plane. For this reason, the water adhering to the left peripheral side surface 10c and the right peripheral side surface 10d and the water flowing from the other surface to the left peripheral side surface 10c and the right peripheral side surface 10d travel down the left peripheral side surface 10c and the right peripheral side surface 10d. To the lower groove-like concavity 12, dropping when entering the lower groove-like concavity 12, or dropping once entering the groove-like concavity 12, or from the groove-like concavity 12 to the lower peripheral side surface 10 b And go down.

  The lower peripheral side surface 10b has an arcuate surface shape that inclines downward from the closed end side toward the opening end and is convex along the circumferential direction. For this reason, the water adhering to the lower peripheral side surface 10b and the water flowing from the other surface to the lower peripheral side surface 10b are partially dropped while flowing along the inclination of the lower peripheral side surface 10b, and the remaining part is the cover body. It flows to the opening end of 9 and drops, or is transferred to the first upper arm 4.

  As described above, when the first upper arm 4 is in a substantially horizontal posture, the four circumferential side surfaces 10a to 10d and the closed end surface 11 have no horizontal portion, so that the water flows down naturally from those surfaces and finally Specifically, it is dropped from the lower peripheral side surface 10b or the like. For this reason, the water drainage from the outer surface of the cover main body 9 is good, and natural drying is possible even if it is left as it is.

  By the way, water also enters each groove-like hidden recess 12. Since the mounting seat surface 13 of the groove-like hidden recess 12 is a vertical surface when the first upper arm 4 is in a substantially horizontal posture, the water adhering to the mounting seat surface 13 naturally flows downward. The upper left and right groove-like concavities 12 are transferred down to the lateral wall surface 15, and the lower left and right groove-like concavities 12 are mostly dropped downward.

  In the upper left and right groove-like concavities 12, the water that enters the groove-like concavity 12 from the upper peripheral side surface 10 a and the closed end surface 11 travels down the vertical wall surface 14 and from the arc surface 16 to the horizontal wall surface 15. . Since the horizontal wall surface 15 is inclined downward toward the left peripheral side surface 10c, the right peripheral side surface 10d, and the closed end side as described above, the water that has descended to the horizontal wall surface 15 follows the inclination of the horizontal wall surface 15. And flows out to the left peripheral side surface 10c, the right peripheral side surface 10d or the closed end surface 11.

In the left and right groove-like concavities 12 on the lower side, the water that enters the groove-like concavity 12 from the left peripheral side surface 10c, the right peripheral side surface 10d, or the closed end surface 11 is directed toward the circular arc surface 16 side. Since it is inclined downward and inclined downward toward the opening end side of the cover body 9, it travels along the horizontal wall surface 15 and descends from the circular arc surface 16 to the vertical wall surface 14 or the installation seat surface 13. Then, the water that has traveled down to the vertical wall surface 14 travels down to the lower peripheral side surface 10 b or drops from the lower end of the vertical wall surface 14. Further, since the mounting seat surface 13 is a vertical surface, the water that has descended to the mounting seat surface 13 from the left peripheral side surface 10c, the right peripheral side surface 10d, the vertical wall surface 14, the horizontal wall surface 15 and the like remains as it is. It is dripped from 13 open side periphery.
Thus, the water that has entered the groove-like hidden recess 12 naturally flows out to the outside, and has excellent water drainage.

  The above is the case where the first upper arm 4 is in a substantially horizontal posture, but the cleaning is not necessarily performed in this horizontal posture. However, it is also expected that the first upper arm 4 is washed in an upwardly inclined posture, or very rarely, in a vertically upward posture. In this case, the four peripheral side surfaces 10a to 10d of the cover main body 9, the vertical wall surface 14, the horizontal wall surface 15 and the arc surface 16 of the groove-like hidden recess 12 are all inclined downward or become vertical surfaces. Since the closed end surface 11 of the main body 9 and the mounting seat surface 13 of the groove-like hidden recess 12 are downward surfaces, the water naturally flows downward and drops. Accordingly, the amount of water droplets remaining on the cover main body 9 is small, and the water repellency is excellent.

  Furthermore, it is expected that the first upper arm 4 is washed in a downwardly inclined posture, or very rarely in a vertically downward posture. In this case, the closed end surface 11 is inclined downward from the center toward the four circumferential side surfaces 10a to 10d, the four circumferential side surfaces 10a to 10d, the vertical wall surface 14, the lateral wall surface 15 and the circular arc surface 16 of the groove-like hidden recess 12. Since all of them are inclined downward or become vertical surfaces, water drainage from each of these surfaces is performed well. On the other hand, the installation seating surface 13 of the groove-like hidden recess 12 is an upward inclined surface or a horizontal upward surface. When the installation seat surface 13 is an inclined surface, water flows along the inclination of the installation seat surface 13 and drops from the periphery on the open side of the installation seat surface 13 or flows to the lateral wall surface 15. Then, it flows out from the mounting seat surface 13 along the inclination of the lateral wall surface 15.

  On the other hand, when the installation seat surface 13 becomes a horizontal plane, some water may remain on the installation seat surface 13. However, the case where the mounting seat surface 13 is an upward horizontal surface is a case where the first upper arm 4 has a vertically downward posture. The posture in which the first upper arm 4 is vertically downward may be during the robot operation, but when the operator cleans the first upper arm 4 or the second upper arm 5, the cleaning operation is extremely difficult. It is a difficult posture. Therefore, it is hardly considered that the first upper arm 4 is cleaned in a posture in which the first upper arm 4 is vertically downward, and when the installation seat surface 13 becomes an upward horizontal surface, some water remains on the installation seat surface 13. However, it cannot be denied that drainage is good.

As described above, regardless of the posture of the first upper arm 4, the end cover 8 has good drainage properties, and even after being washed, it is naturally dried in a relatively short time even if left as it is.
After washing, water drops remaining on the end cover 8 may be quickly wiped with a cloth. In this case, according to the present embodiment, the cloth can be effectively prevented from being caught on the hexagonal head 17a of the bolt 17. Further, water drops remaining behind the bolts 17 on the mounting seat surface 13 can be easily wiped off with a cloth.

  That is, FIGS. 5A to 5C illustrate in time series the case where the outer surface near the groove-like hidden recess 12 on the upper right side (left side in FIG. 5) of the cover body 9 is wiped with the cloth C. is there. FIG. 5A shows a state in which the cloth C is applied to the two surfaces at the corners of the opening end of the cover body 9 (outer edges of the mounting seat surface 13) in the state of starting wiping. FIGS. 5B and 5C show a state where the cloth C is wiped from the state of FIG. 5A toward the closed end of the cover body 9.

  In the state of FIG. 5 (a), the cloth C is only addressed to two surfaces that are substantially perpendicular to the corners of the opening end of the cover body 9, so that the hexagon head 17a is not touched. In the state of FIG. 5 (b), a part of the cloth C is addressed to the two corners of the opening end of the cover body 9, and the vertical side wall 14 and the upper peripheral side surface 10a intersect each other on the moving side front portion. It exists on the diagonal line which connects the ridge part M (refer also FIG. 3) where the ridge part M (refer also FIG. 3) and the horizontal wall surface 15 and the right peripheral side surface 10d cross | intersect. At this time, the position where the cloth C, which is partly in contact with the two surfaces of the corner of the open end of the cover body 9, is in contact with both ridges M and N is away from the corner of the open end. As shown in FIG.2 (c), it will be in the state which covers the installation seat surface 13 with a clearance gap, and it is difficult to touch the hexagon head 17a. As shown in FIG. 5C, this state is maintained until the portion of the cloth C pressed by the fingers passes through the two corners of the open end of the cover body 9. Similarly, when the cloth C is moved in the direction opposite to the direction shown in FIG. 5 to wipe off the water, or when the cloth C is moved from the top to the bottom and from the bottom to the top, the cloth C is the hexagon head of the bolt 17. Touching 17a is prevented as much as possible.

  Further, when water drops remain in the mounting seat surface 13 and are wiped off, a cloth is interposed between the hexagon head 17a and the vertical wall surface 14, the horizontal wall surface 15 and the arc surface 16 as shown in FIG. Insert C. At this time, if the gap of the dimension D between the hexagon head 17a and the vertical wall surface 14, the horizontal wall surface 15 and the circular arc surface 16 is smaller than the height T of the hexagon head 17a, even if the cloth C is thin, it is inserted into the gap. It is difficult to reach the installation seat 13 even if it can be inserted.

  However, in this embodiment, since the dimension D of the gap is equal to or greater than the height T of the hexagon head 17a, it is easy to put the cloth C into the gap and easily reach the installation seat surface 13, so that water droplets remaining in the gap Can be easily wiped off. Incidentally, in the small robot as in this embodiment, as the mounting bolt 17 of the cover main body 9, one having a shaft diameter of 3 to 5 mm is used. The height of the bolt 17 including the washer 19 of the hexagon head 17a is 3 to 4.5 mm. And, if there is such a gap, it is sufficient to insert the end of the cloth C, and the water drop can be easily wiped with the cloth C.

  As described above, according to the present embodiment, the water repellency of the outer surface of the cover body 9 is excellent. Moreover, since the hexagon head 17a of the bolt 17 is exposed, the bolt 17 can be removed by rotating the hexagon head 17a with a spanner. Therefore, the cover main body 9 can be easily removed and the inside of the first upper arm 4 can be inspected, resulting in excellent maintainability.

  In addition, although the hexagon head 17a is exposed, it is in the concealed state in the groove-like concavity 12, so when wiping the outer surface of the cover body 9 with the cloth C, Generation | occurrence | production of the malfunction that the cloth C is caught by the hexagon head 17a can also be prevented as much as possible. In addition, the hexagon head 17a has no portion such as a hexagonal hole for collecting water, and the groove-like concavity 12 is also open to the outside, so that water hardly accumulates and has excellent water drainage.

(Other embodiments)
7 to 9 show an end cover 21 according to another embodiment of the present invention. The end cover 21 is configured mainly by a container-shaped cover main body 22 having one end opened and the other end closed, and the opening end surface of the one end serving as a mounting surface 22 a for the first upper cover 4. . The cover main body 22 has a slightly horizontally long cylindrical shape, and a groove-like concavity 23 is formed by recessing four portions of the cylindrical peripheral surface in an L shape inward of the cover main body 22. These groove-like hidden recesses 23 divide the cylindrical peripheral surface of the cover body 22 into upper, lower, left and right four circumferential side surfaces 24 a to 24 d.

The upper, lower, left and right peripheral side surfaces 24a to 24d have an arcuate surface shape that protrudes outward along the circumferential direction. The closed end face 25 has a flat surface shape.
The groove-like concavity 23 is formed from the mounting seat surface 26, the vertical wall surface 27, the horizontal wall surface 28, and the arc surface 29 similar to the mounting seat surface 13, the vertical wall surface 14, the horizontal wall surface 15 and the arc surface 16 in the above-described embodiment. Become.

  Further, a through hole 30 for the bolt 17 is formed in the mounting seat surface 26. The through-hole 30 has a groove-like concavity 23 that is formed in the groove-like concavity 23 more than the diagonal L when imagining a diagonal L connecting the two intersections P2 and P3 assumed on the mounting seat surface 26 as in the above-described embodiment. It is determined to be located on the back side. Further, the dimension D of the installation seat surface 26 in the direction toward the vertical wall surface 27, the horizontal wall surface 28 and the circular arc surface 29 is the hexagon head 17a, the vertical wall surface 27 and the horizontal wall surface of the bolt 17 with the washer 19 passed through the bolt 17. 28 and the arc surface 29 are determined to have a dimension that is equal to or greater than the height T of the hexagon head 17 a including the washer 19.

  In the end cover 21 having such a cover body 22 as a main body, when the first upper arm 4 is in a horizontal posture, when the first upper arm 4 is in a diagonally upward posture, a vertically upward posture, and a diagonally downward posture, four turns About the side surfaces 24a-24d and the obstruction | occlusion end surface 25, the excellent water drainage property is exhibited like the above-mentioned one embodiment. In addition, about the drainage property of the groove-shaped hidden recessed part 23, it is the same as that of one above-mentioned embodiment about all the attitude | positions of the 1st upper arm 4. FIG.

By the way, when the first upper arm 4 is in the vertically downward posture, the four circumferential side surfaces 24a to 24d may be vertical, but the closed end surface 25 is a horizontal flat surface, so that water drainage is reduced. To do. However, as described above, the first upper arm 4 is hardly washed in a vertically downward posture.
The reason for this will be described again. Usually, cleaning is performed in a posture in which each part of the robot can be easily cleaned. This easy-to-clean posture is the horizontal, slightly downward or slightly upward posture for the first upper arm 4, particularly the slightly downward posture shown in FIG.

On the other hand, the posture in which the first upper arm 4 is vertically downward is a posture that is taken during work such as gripping a workpiece. Do not wash in a posture.
From the above, since the first upper arm 4 is usually washed in a state of being almost horizontal, even if the closed end surface 25 is the flat cover body 22, it exhibits good water drainage. .

(Other embodiments)
The present invention is not limited to the embodiment described above and shown in the drawings, and can be expanded or changed as follows.
The left and right side surfaces 10c and 10d of the cover body 9 may also be formed in a trapezoidal shape that narrows from the open end toward the closed end. Further, the left and right side surfaces 10c and 10d may be formed in a circular arc shape that protrudes outward along the circumferential direction.
The closed end surface 11 of the cover body 9 may be a flat surface instead of a dome shape.
The groove-like hidden recesses 12 and 23 that divide the cover main body 9 and 20 into a plurality of surfaces may be formed to divide the peripheral surface into two surfaces, or five or more. It may be formed and partitioned into five or more surfaces.

  In the drawings, 1 is a first upper arm, 8 and 20 are end covers, 9 and 20 are cover bodies, 10a to 10d and 24a to 24d are vertical and horizontal peripheral surfaces, 11 and 25 are closed end surfaces, and 12, 23 Is a groove-like concavity, 13, 26 is a mounting seat surface, 14, 27 are vertical wall surfaces, 15, 28 are horizontal wall surfaces, 16, 29 are arc surfaces, 17 is a bolt, 17a is a hexagon head (head), 18, Reference numeral 30 denotes a through hole, and 19 denotes a washer.

Claims (4)

In the end cover of the arm that is the arm of the robot and that is rotated in the vertical direction, the arm is placed on one end of the arm and fixed with a bolt.
One end is opened and the other end is closed, with the container-shaped cover body having the opening end surface of the one end as a mounting surface to the arm,
Of the peripheral surface of the cover body, an L-shape is formed in a portion that divides the peripheral surface into a plurality of surfaces in the circumferential direction, with the portion on the opening end side of the one end being left inward. Provided with a groove-like hidden recess formed so as to extend from the opening end side toward the closed end of the other end,
Of the peripheral surfaces of the cover body, at least the surface located above and below is formed in an arcuate surface that is convex outward with respect to the circumferential direction,
The groove-like hidden recess is located on the opening end side of the cover body and has a mounting seat surface of the bolt head formed with a through hole for passing the bolt, and two adjacent sides of the mounting seat surface, Two wall surfaces extending toward the closed end of the cover body,
The two wall surfaces of the groove-like hidden recess are inclined so as to widen the opening of the groove-like hidden recess from the corner portion formed by the intersection of the two wall surfaces toward the peripheral surface of the cover body, and , Formed so as to be inclined so as to widen the depth of the groove-like concavity from the mounting seat surface toward the closed end of the cover body,
Further, the through hole is present on the diagonal line of the installation seat surface connecting the two wall surfaces and the apex formed by the installation seat surface, or is present in the depth of the groove-like hidden recess from the diagonal line, and The dimension of the mounting seat surface in the direction toward the two wall surfaces is such that the distance between the head of the bolt passed through the through hole and the two wall surfaces of the groove-like concavity is the head of the bolt. Set to a dimension that is greater than or equal to the height of the part,
An end cover of a robot arm. The cover body has a rectangular container shape,
The groove-like concavity is formed on four ridges on the peripheral surface of the cover body by recessing the ridges toward the inside of the cover body leaving a portion on the opening end side of the one end. The end cover of the arm of the robot according to claim 1, wherein   The at least upper and lower surfaces of the peripheral surface of the cover body are inclined so that a space between the upper and lower surfaces gradually narrows from the open end toward the closed end of the other end. The end cover of the arm of the robot according to 2.   The end cover of the arm of the robot according to any one of claims 1 to 3, wherein the closed end surface of the cover body is formed in a circular arc shape that is convex outward.