JP2001162578A - Robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase longevity of packing, to reduce cost and to improve outer appearance of a robot provided with a cover on an outer wall part of a frame of a robot arm through the packing for sealing. SOLUTION: A cover 43 to cover a belt transmission mechanism part and to attempt dustproofing and drip-proofing is provided on an outer wall part of a right side wall part 22 of a frame 20 to constitute a first arm 13. The cover 43 is constituted in a shallow bottom cover shape having a main plats part 43a and a peripheral wall part 43b rising to the left from its circumference of synthetic resin. Packing 45 for sealing made of NBR sponge is provided in a clearance between a head end surface of a rising wall part 22a of the right side wall part 22 and an inner peripheral edge part of the cover 43. The cover 43 is applied over the right side wall part 22 in a state where packing 45 for sealing is arranged inside, it is screwed up on the peripheral wall part 43b, and its bush is connected to stop falling. At this time, the packing 45 is compressed at a compression deformation rate of less than 30%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot in which a cover is attached to an outer wall of a frame constituting a robot arm via a packing for sealing.

[0002]

An industrial robot, for example, a multi-joint (6-axis) robot, connects a plurality of arms so as to be able to rotate (turn) in order at joints, and drives the joints to rotate. And a built-in motor and speed reducer. FIG. 6 shows an example of the configuration of a joint portion of this type of conventional robot. In this case, a lower end of a second arm 2 is attached to an upper end of a first arm 1 by an axis J2 extending in a horizontal direction. Are connected so as to be rotatable around the center.

In this case, the casting frame 3 constituting the frame of the first arm 1 has a bifurcated upper half and extends upward, and a lower end of the second arm 2 is provided. Is rotatably supported by a pair of left and right bearings 4 in a state sandwiched therebetween. And the first arm 1
The rotational force of a motor (not shown) incorporated in the lower portion of the (frame 3) is located outside the right side wall of the frame 3 and is transmitted to the pulley 6 via the belt 5. The rotation of No. 6 is transmitted to the second arm 2 via a speed reducer 7 composed of a harmonic drive.

At this time, a metal (cast) cover 8 is provided outside the right side wall of the frame 3 so as to cover the belt transmission mechanism. A plurality of screw holes 3a are formed in the outer peripheral edge of the right side wall of the frame 3 at a plurality of locations, and a flange 8a is provided on the outer peripheral portion of the cover 8 along the outer peripheral edge of the right side wall of the frame 3. Is formed with a screw insertion hole 8b corresponding to the screw hole 3a.

The cover 8 is provided with a screw insertion hole 8b with a thin rubber packing 9 sandwiched between the flange 8a and the outer peripheral edge of the right side wall of the frame 3.
Further, the screw 10 is attached to the screw hole 3a by tightening the screw 10 through the hole 9a of the packing 9. Thus, by being sealed by the packing 9, dustproofness and dripproofness are ensured.
The cover 8 is similarly attached to the left side wall of the frame 3 with the packing 9 interposed therebetween.

However, in the above-described conventional mounting structure of the cover 8 and the packing 9, the tightening force of the screw 10 tends to be large, and the packing 9 is greatly deformed, so that the service life is relatively short. For this reason, the packing 9 cannot be repeatedly used (detached) many times. For example, it is necessary to replace the packing 9 with a new one when the cover 8 is removed at the time of maintenance or the like.
In this case, an expensive gasket seal or the like is required to make the packing 9 detachable. Moreover, in the above-mentioned thing, since the packing 9 appeared on the external appearance, the appearance was poor.

In the above-mentioned robot, a cast cover 8 having no risk of deformation such as bending deformation is employed in order to obtain the reliability of the seal with the frame 3.
A case in which the cover 8 itself becomes expensive and the position of the screw insertion hole 8b of the cover 8 must be corrected due to a processing error between the position of the screw hole 3a of the frame 3 and the position of the screw insertion hole 8b of the cover 8. There was also.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cover in which an outer wall portion of a frame of a robot arm is provided via a packing for sealing so that the packing has a long life. An object of the present invention is to provide a robot that can reduce costs and improve the appearance.

[0009]

According to the present invention, there is provided a robot in which a cover is provided on an outer wall portion of a frame of a robot arm via a sealing packing, and the packing is made of thick foam rubber. In addition, the present invention is characterized in that the cover is configured to be attached to the frame outside the sealing portion by the packing in a state where the packing is compressed and deformed (the invention of claim 1).

[0010] According to this, the gap between the frame and the cover is sealed by the packing to prevent dust and drip. At this time, the cover is in a state utilizing the reaction force due to the compressive deformation of the packing. Thus, the cover can be attached to the frame in a sealed state without applying excessive tightening force or the like to the packing. In this case, since the packing is made of thick foam rubber, the reaction force can be maintained for a long time by a slight compression deformation, and the resilience when external force is removed is excellent. Thus, it is possible to repeatedly use (detach) many times, and the material can be relatively inexpensive. And the cover is
Since the gasket is attached to the frame outside the seal portion of the gasket, the cover can be attached without the gasket appearing in the appearance.

As a result, according to the first aspect of the present invention, it is possible to obtain an excellent effect that the packing can have a long life, the cost can be reduced, and the appearance can be improved. It is. In addition, as the foamed rubber, for example, an NBR sponge which is excellent in cost can be used, and in this case, a rubber having a hardness of 10 to 25 can be used. Furthermore, a silicone foam rubber having more excellent physical properties (oil resistance, water resistance, etc.) can be used.

At this time, more specifically, the cover is formed in a shallow bottom lid shape having a main plate portion and a peripheral wall portion rising from the periphery of the main plate portion and covering the outer wall portion of the frame.
The packing may be arranged along the inner peripheral edge portion of the cover, and the cover may be screwed to the frame at the peripheral wall portion and the bush may be connected to the frame as a retaining member (claim 2). According to this, the direction in which the screw is tightened and the direction in which the packing is compressed are different, so that the screwing serves as a so-called retaining function, and an excessive compression force does not act on the packing due to the screw tightening force. And even if the packing becomes large, the positioning becomes easy and the assembling work becomes simple, and the screwing position comes to the peripheral wall portion, so that the screw becomes difficult to see and the appearance is further improved. be able to.

By the way, when the cover is attached to the frame, it is desirable that the compressive deformation rate of the packing is not more than 30% (the invention of claim 3), thereby ensuring good reversibility of the packing. be able to. If the compressive deformation rate of the packing exceeds 30%, there is a possibility that the resilience at the time of removing the external force is deteriorated.

Further, since the thick packing is used, even if the gap between the frame and the cover is large (even if the gap is uneven), it is possible to seal.
The cover can be made of synthetic resin instead of metal (the invention of claim 4). According to this, the cost of the cover can be reduced, the weight can be reduced, and the processing error of the mounting position between the frame and the cover can be reduced without correcting the hole forming position.
It can be easily absorbed by the gap between the frame and the cover.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an articulated (6-axis) type robot for assembly will be described below with reference to FIG.
This will be described with reference to FIG. FIG. 5 schematically shows an external configuration of a main body 11 of the articulated robot according to the present embodiment. The robot main body 11 has a six-axis robot arm on a base 12 and has a tip at its tip. It is configured by attaching a tool such as a hand (not shown).

Specifically, a first arm 13 extending upward is connected to the base 12 so as to be rotatable (turnable) around a vertical axis J1. The lower end of the second arm 14 extending upward in a U-shape is connected to be rotatable about a horizontal axis J2. A base end of a third arm 15 is connected to a front end of the second arm 14 so as to be rotatable about a horizontal axis J3, and a base of a fourth arm 16 is connected to a front end of the third arm 15. The end is axis J4
Are connected so as to be coaxially rotatable around the center. A fifth arm 17 is rotatably connected to the distal end of the fourth arm 16 around the axis J5.
A flange portion 18 to which a tool such as the hand is detachably attached is provided so as to be coaxially rotatable about an axis J6.

As will be shown later as a part (first arm 13), a servo motor for driving each axis and a joint located at each joint are provided in the robot body 11. , Bearings, reduction gears, oil seals and the like. A cover is provided on the outer wall of each of the arms 13 to 17. The robot body 1
1 is connected to a robot controller (not shown) including a microcomputer and the like, and the servo motors and the like of the respective axes are controlled by the robot controller to perform various operations (eg, assembling work). .

Here, the first of the robot arms is
The structure of the arm 13 will be described as a representative. As shown in FIG. 4 and the like, the first arm 13 is configured such that, when viewed from the front, the upper half thereof extends upward with two branches on both left and right sides. 2
The lower end of the lower frame 19 of the arm 14 is connected. Further, when viewed from the side, it has a shape in which it extends slightly obliquely upward and has a rounded upper part. The first arm 13 is configured such that a servomotor and a mechanical unit are mounted on a metal (casting) frame 20 serving as a body thereof, as described later, and both right and left side walls are covered with covers.

That is, as shown in FIG.
Reference numeral 0 denotes a main portion 20a which is located substantially in the lower half thereof and has a rectangular box shape, a left side wall portion 21 extending upward from the left side of the main portion 20a, and a right side extending upward from the right side of the main portion 20a. It is configured to have the wall part 22 integrally. further,
The outer peripheral edge of the left side wall 21 is integrally provided with a rising wall 21a that rises to the side (left side in the figure), and the outer peripheral edge of the right side wall 22 is also shown in FIG. As described above, the rising wall portion 22a that rises to the side (to the right in the figure) is provided integrally. A circular opening 21b is formed in the upper part of the left side wall part 21 and a circular opening part 22b is formed in the upper part of the right side wall part 22 correspondingly.

In the main portion 20a of the frame 20, J
A two-axis servomotor 23 is disposed in a horizontal (right) direction. As shown in FIG. 3, the tip of the servo motor 23 projects rightward from the rectangular opening 22c of the right side wall 22, and the rotary shaft 23a has a small diameter formed of a toothed pulley. A drive pulley 24 is mounted.

On the other hand, the lower frame 19 of the second arm 14 disposed between the left side wall 21 and the right side wall 22
Is hollow and has a circular opening 19 on its left side wall.
a is formed, and a circular concave portion 19b that is concave to the left is formed in the right side wall portion. The left side wall 2
The cylindrical portion 25 is fixed to the one circular opening 21a. Between the outer peripheral surface of the cylindrical portion 25 and the inner peripheral surface of the circular opening 19a of the lower frame 19, a bearing 26 made of, for example, a general-purpose rolling bearing is interposed. An oil seal 27 is provided on the outside (left side). It should be noted that necessary wiring and the like are passed through the inside of the cylindrical portion 25.

On the other hand, a shaft support 28 is fixed to the circular opening 22b of the right side wall 22. On the left side surface of this shaft support portion 28, it projects into the circular concave portion 19b of the lower frame 19,
A circular spline 29 and a ring-shaped bearing support 30 which constitute a part of a speed reducer described later are fixed in a so-called co-tightened state. Between the outer peripheral surface of the bearing support portion 30 and the inner peripheral surface of the circular concave portion 19b, a bearing 31 formed of, for example, a cross roller bearing capable of receiving loads in both the thrust direction and the radial direction is interposed. In addition, an oil seal 32 is provided just outside (right side) of the bearing 31.

The oil seal 32 has the outer circumferential surface of the circular spline 29 made of hardened steel as a sliding surface. Thus, the lower frame 19 of the second arm 14
Is rotatably supported on the frame 20 of the first arm 13 in a so-called double-sided structure around the axis J2 by the two bearings 26 and 31. With this,
The two bearings 26 and 31 can be small and inexpensive, and the rigidity of the frame 20 can be small as compared with the case of the cantilever structure. Further, the oil seals 27 and 32 can withstand use in, for example, a mist environment.

A shaft 33 is supported at the center of the shaft supporting portion 28 through a bearing 34 so as to penetrate in the left-right direction. An oil seal 35 is also provided on the right side of the bearing 34. This shaft 33
Is coincident with the axis J2. As shown in FIG. 3, a driven pulley 36 composed of a large-diameter toothed pulley is attached to the right end side of the shaft 33, and between the driven pulley 36 and the driving pulley 24. A toothed belt (timing belt) 37 is stretched. At this time, the drive pulley 24, the driven pulley 36, and the toothed belt 37 are located on the outer surface side of the right side wall 22 of the frame 20.

Further, a speed reducer 38 is provided between the left side of the shaft 33 and the circular recess 19b of the lower frame 19. The reduction gear 38 is composed of, for example, a general-purpose harmonic drive. As is well known, a wave generator 39 including an elliptical cam and a ball bearing on the outer periphery thereof, and a cup-shaped flex spline (elastic gear) disposed on the outer periphery thereof. ) 40 and the circular spline (internal gear) 29 meshing with the outer periphery thereof.

At this time, the wave generator 39
Is fitted and connected to the shaft 33, and the base end of the flexspline 40 is fixed to the inner bottom of the circular recess 19 b of the lower frame 19 by a mounting member 41. Further, as described above, the circular spline 29 is fixed to the shaft support 28 (the right side wall 22). The mounting member 41 is provided with a bearing 42 for supporting the tip of the shaft 33.

Thus, the driving force of the servo motor 23 is controlled by the driving pulley 24, the toothed belt 37, and the driven pulley 36.
Is transmitted to the shaft 33 via a belt transmission mechanism composed of
The second arm 14 is rotated about the axis J2 with respect to the first arm 13.

On the outer wall (right side) of the right side wall 22 of the frame 20, there is provided a cover 43 for covering the belt transmission mechanism and for preventing dust and drip. As shown in FIGS. 3 and 4, the cover 43 is attached to the right side wall 22.
A right bottom surface of the main plate portion 43a and a peripheral wall portion 43b that rises to the left from the periphery of the main plate portion 43a and cover the outer peripheral surface side of the rising wall portion 22a. It is provided so as to cover the wall 22 from the right side. In this embodiment, the cover 43 is manufactured by, for example, vacuum molding of a synthetic resin, and has a thickness of, for example, 3 mm.

At this time, as shown in a partially enlarged view in FIG. 2, the outer peripheral surface of the rising wall portion 22a of the right side wall portion 22 intermittently covers a plurality (for example, 9 22d) is formed. On the other hand, a screw insertion hole is formed in the peripheral wall portion 43b of the cover 43 at a position corresponding to the screw hole 22d.
In this embodiment, as shown in FIG. 2, a metal bush 44 is fitted and embedded in the screw insertion hole.

The rising wall 2 of the right side wall 22
2a and the inner peripheral edge of the cover 43 (the main plate 4
The gap provided between the inner wall 3a and the inner peripheral wall 43b) is provided with a sealing gasket 45 for sealing. The packing 45 is formed from foamed rubber, such as NBR sponge, from the rising wall 22a.
(Annular) along the end face of
The thickness is about 0 mm. In addition, this packing 4
The hardness of 5 is set to 10.

The cover 43 is placed on the right side wall 22 with the packing 45 arranged along the inner peripheral edge thereof, and as shown in FIG. To be detachably attached. At this time, the packing 45
It is compressed and deformed by being sandwiched between the leading end surface of the rising wall portion 22a. The screwing position is set so that the compression deformation rate is 30% or less, in this case, about 2 to 3 mm. I have. Further, the coupling position (screw fixing position) of the cover 43 to the frame 20 is outside the sealing position by the packing 45.

Although not described in detail, the outer wall (left side) of the left side wall 21 of the frame 20 is shown in FIG.
Similarly, the cover 47 is attached by screwing with the packing 48 interposed therebetween. Furthermore, as described above, each arm 1 other than the first arm 13
Covers are similarly provided on the outer walls 4 to 17.

Next, the operation of the above configuration will be described. When attaching the cover 43 to the right side wall 22 of the frame 20, the packing 45 is disposed along the inner peripheral edge of the cover 43 as described above, and the cover 43 is attached to the right side wall 22.
In a state where the packing 45 is compressed and deformed by 2 to 3 mm in such a manner that the packing 45 is covered with the screw 46, a plurality of screws are screwed by the screws 46.

In this case, the direction in which the screw 46 is tightened is different from the direction in which the packing 45 is compressed, and the cover 43 utilizes the reaction force due to the compression deformation of the packing 45 so that the screw serves as a stopper, so to speak. It can be attached to the right side wall 22. For this reason, unlike the conventional method in which the flange portion 8a of the cover 8 is screwed to the frame 3 with the packing 9 interposed therebetween, an excessive compression force acts on the packing 45 by the tightening force of the screw 46. And no excessive compression deformation occurs. Also, unlike the conventional one, since the cover 43 is formed in the shape of a shallow lid, even if the packing 45 becomes large, the positioning of the packing 45 with respect to the cover 43 and the positioning of the cover 43 with respect to the right side wall portion 22 are performed. And the assembling work is simplified.

Further, since the cover 43 is made of synthetic resin, there is a possibility that a slight bending may occur at the time of attachment. Packing 45 without causing
Thus, reliable sealing performance can be obtained. As a result, the cover 8 need not be made of a metal (casting) having high rigidity as in the related art, and the cost and weight can be reduced by using the cover 43 made of a synthetic resin. Further, even if there is a slight processing error between the position of the screw hole 22d of the right side wall portion 22 and the position of the screw insertion hole (the bush 44) of the cover 43, even if the hole forming position is not corrected, etc. The gap between the right side wall 22 and the cover 43 can easily absorb the error.

In the state where the cover 43 is attached,
The gap between the right side wall portion 22 (rising wall portion 22a) and the cover 43 is sealed by the packing 45 to prevent dust and drip. The packing 45 made of thick foam rubber is used. The reaction force can be maintained for a long period of time by a slight (30% or less) compressive deformation, and a long-term stable sealing property can be maintained. In this case, the packing 45 for sealing is made of foamed rubber (NBR sponge).
Because it is made of, compared with expensive gasket seal etc.
It can be made relatively inexpensive in terms of material.

At this time, the packing 45 is attached to the cover 4.
3 and does not appear in the appearance unlike the conventional one, so that the appearance can be improved, and
Since the screwing position comes to the peripheral wall portion 43b of the cover 43,
The head of the screw 46 is also relatively inconspicuous, and the appearance can be improved from this point as well.

During maintenance such as refueling, inspection, and replacement of parts, the cover 43 is once removed from the right side wall 22 of the frame 20 and is reattached after maintenance is completed. In this case, the packing 45 made of the thick foam rubber is different from the conventional disposable rubber thin packing 9 in that the packing 45 has a reaction force (rubber-like elasticity) as described above. It can be maintained for a long period of time, and has excellent resilience when external force is removed, and can be used (removed) repeatedly. In particular, by setting the compression deformation rate to 30% or less, good reversibility of the packing 45 can be ensured.

As described above, according to the present embodiment, the frame 2
It is possible to extend the service life of the seal packing 45 provided between the cover 0 and the cover 43 at a low cost, unlike the conventional case where the packing 9 has to be replaced frequently. Thus, an excellent effect that cost can be significantly reduced and the appearance can be improved can be obtained. In particular, in this embodiment, since the cover 43 is made of a synthetic resin, the cover 43 can be made inexpensive, and the cost can be further reduced.

In the above embodiment, the NBR sponge, which is excellent in cost, is used as the material of the packing 45. However, various materials such as silicone foam rubber having more excellent physical properties (oil resistance, water resistance, etc.) are used. Foam rubber can be employed. It is preferable to adopt a material having a hardness of 10 to 25 as the material of the packing. As a matter of course, the cover 43 may be made of the same metal as before. In addition, the present invention does not depart from the gist of the present invention. For example, various modifications can be made to the configuration of the robot arm, the mechanical configuration of the robot body itself such as a bearing structure and a reduction gear, and the coupling structure between the frame and the cover. The present invention can be carried out with appropriate changes within the range.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a longitudinal sectional front view of a first arm portion.

FIG. 2 is an enlarged vertical sectional front view of a screwed portion of a cover.

FIG. 3 is an exploded perspective view of a right wall portion of a first arm.

FIG. 4 is a perspective view of a first arm portion.

FIG. 5 is a side view showing the external configuration of the robot body.

FIG. 6 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

In the drawing, 11 is a robot body, 13 is a first arm, 14
Is the second arm, 19 is the lower frame, 20 is the frame,
21 is a left side wall, 22 is a right side wall, 21a and 22a are rising walls, 22d is a screw hole, 43 and 47 are covers, 43
a is a main plate portion, 43b is a peripheral wall portion, 44 is a bush, 45,
48 is a packing and 46 is a screw.

Claims (4)

[Claims] A cover is provided on an outer wall portion of a frame constituting a robot arm, and a packing for sealing is interposed in a gap between the frame and the cover. And the cover is attached to the frame at a position outside the seal portion of the packing in a state where the packing is compressed and deformed. 2. The cover has a main plate portion and a peripheral wall portion rising from the periphery of the main plate portion, has a shallow bottom lid shape covering the outer wall portion of the frame, and the packing is formed on an inner peripheral edge portion of the cover. 2. The robot according to claim 1, wherein the robot is disposed along the peripheral wall, and the peripheral wall is coupled to the frame with a screw and a bush thereof as a stopper. 3. The robot according to claim 1, wherein a compression deformation rate of the packing is 30% or less when the cover is attached to a frame. 4. The robot according to claim 1, wherein the cover is made of a synthetic resin.