JP6105913B2 - Parallel link robot - Google Patents

Description

  The present invention includes a base, a movable plate to which an end effector is attached, three arms that are rotatably connected to the base, and three sets of links that respectively connect the distal ends of the arms to the movable plate. It relates to parallel link robots.

  Conventionally, a parallel link robot is known as an example of a robot used for picking work. In general, the parallel link robot is required to move the movable plate while keeping the posture of the movable plate with respect to the base constant. Therefore, various structural modes have been proposed for the three arms and three sets of links for connecting the base to the movable plate (see, for example, Patent Document 1).

  According to an example disclosed in Patent Document 1, a set of links includes two linking bars, and an arm, a set of links, and a movable plate form a parallel link mechanism. The two linking bars are arranged in parallel to each other and are arranged so as to sandwich the arm tip.

  According to the modification disclosed in Patent Document 1, one set of links is composed of one oar, and the oar is attached to the arm tip at one end and attached to the movable plate at the other end. A cardan joint is used to connect the all arm to the movable plate. Focusing on one end of the all, the arm tip and all base end are bifurcated, and the arm tip and all base end are connected via a cross pin. The all other end is configured in the same manner.

US Pat. No. 4,976,582

  In the above example of Patent Document 1, a total of six linking bars are required, resulting in an increase in assembly man-hours and an increase in weight due to an increase in the number of parts. In the modified example of Patent Document 1, the number of parts required for the link is reduced, so that such a problem can be solved.

  However, in this modification, the bifurcated arm tip is connected to the bifurcated all base end via a cross pin, and the arm is supported on both ends by the all and the all is supported on both ends by the arm. For this reason, when the all base end portion rotates with respect to the arm tip portion, the all base end portion immediately interferes with the bifurcated arm tip portion. For this reason, the rotation range of the oar is limited, and thereby the movable range of the end effector is also limited. In the modified example of Patent Document 1, when the end effector movable range is to be increased, the entire robot must be enlarged, and when the entire robot is to be reduced, the end effector movable range must be reduced.

  Accordingly, an object of the present invention is to expand the movable range of the end effector without increasing the size of the robot, or to reduce the size of the robot without reducing the movable range of the end effector.

  The present invention has been made to achieve the above object, and a parallel link robot according to the present invention includes a base, a movable plate to which an end effector is attached, and three rotatably connected to the base. An arm, and three links each connecting the distal end portion of the arm to the movable plate, and the link is connected to the distal end portion of the arm via a first joint portion at a base end portion thereof. The distal end portion of the arm is connected to the movable plate via a second joint portion, and the first joint portion is parallel to a rotation axis of the arm with respect to the base and is perpendicular to the first axis. The base end portion of the link is coupled to the distal end portion of the arm so as to be rotatable around two axes of a second axis, and the second joint portion includes a third axis parallel to the first axis and the second axis 4th axis perpendicular to 3rd axis The distal end portion of the link is connected to the movable plate so as to be rotatable around two axes, and the base end portion of the link is cantilevered on the distal end portion of the arm via the first joint portion. The tip end portion of the link is cantilevered by the movable plate via the second joint portion.

  According to the said structure, since the number of the links which connect each arm to a movable plate is one, the number of parts and weight of a parallel link robot can be made small. Since this link is cantilevered by both the arm and the movable plate, the range in which the link can be rotated without interfering with the structure of the joint is larger than when a double-supported structure is applied to the joint. be able to. Thereby, the movable range of the end effector can be expanded without increasing the size of the entire robot, or the entire robot can be reduced without decreasing the movable range of the end effector.

  The first joint portion includes a first bearing provided at the tip portion of the arm, and a first rotating shaft that is inserted into the first bearing and supported rotatably around the first axis. The base end portion of the link is connected to one end portion of the first rotating shaft so as to be rotatable around the second axis, and the first rotating shaft is detachably attached to the first bearing. Good.

  According to the said structure, the cantilever support in a 1st joint part is realizable. Moreover, if the 1st rotating shaft is removed from a 1st bearing, it can be removed from an arm with the base end part of a link. For this reason, the maintenance work of a 1st joint part and a link can be performed quickly and simply.

  The second joint portion includes a bearing provided on the movable plate, and a fourth rotating shaft that is inserted into the fourth bearing and is rotatably supported around the fourth axis. The distal end portion may be connected to one end portion of the fourth rotation shaft so as to be rotatable around the third axis, and the fourth rotation shaft may be detachably attached to the fourth bearing.

  According to the said structure, the cantilever support in a 2nd joint part is realizable. Moreover, if the 4th rotating shaft is removed from a 4th bearing, it can remove from the arm with the front-end | tip part of a link. For this reason, the maintenance work of a 2nd joint part and a link can be performed quickly and simply.

  As apparent from the above description, according to the present invention, the movable range of the end effector can be expanded without increasing the size of the robot, or the robot can be mounted without reducing the movable range of the end effector. It can be downsized.

It is the perspective view which looked at the parallel link robot which concerns on embodiment from the top. It is a skeleton figure of the link shown in FIG. 1, a 1st joint part, and a 2nd joint part. It is a perspective view which shows the periphery site | part of the 1st joint part shown in FIG. It is sectional drawing which shows the internal structure of the 1st joint part shown in FIG. It is a perspective view which decomposes | disassembles and shows the link shown in FIG. It is a perspective view which shows the link which concerns on a modification. It is a perspective view which decomposes | disassembles and shows the rotary actuator shown in FIG.

  Hereinafter, embodiments will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or corresponding element through all the figures, and the detailed description which overlaps is abbreviate | omitted.

  Drawing 1 is a perspective view which looked at parallel link robot 1 concerning an embodiment from the top. A parallel link robot 1 (hereinafter simply referred to as “robot”) shown in FIG. 1 is arranged in a work space in a production factory for food, medicine, cosmetics, small electronic components, and the like, and picking work, boxing work, and parts assembling work. It is suitably used as a robot that performs various operations such as the above. Since the robot 1 according to the present embodiment can increase the movable range while reducing the size of the robot as described later, the robot 1 is highly versatile.

  As shown in FIG. 1, the robot 1 mainly includes a base 2, a movable plate 3, three rotary actuators 4, three arms 5, three links 6, and three first joint portions. 7 and three second joint portions 8. The base 2 is installed in the work space, and the movable plate 3 moves three-dimensionally within a movable range defined by the rotation range of the arm 5 and the link 6. An end effector (not shown) is detachably attached to the movable plate 3.

  In the present embodiment, as an example, the base 2 is installed in a horizontal posture, and the movable plate 3 is located below the base 2, and the concept of direction in the following description is based on this arrangement. However, since the base 2 can be installed in an arbitrary posture, the concept of direction can be changed according to the way the robot 1 is installed. The end effector (not shown) is a tool for various operations as described above, such as a hand or a manipulator, and the movable plate 3 has a structure 3a for attaching the end effector to the lower surface thereof. An effector actuator 9 that rotationally drives the end effector is provided on the upper surface of the movable plate 3 as necessary.

  The rotary actuator 4 is an electric motor housed in a housing 4a, and the speed reducer unit 10 is provided in the housing 4a of the rotary actuator 4. The reduction gear unit 10 decelerates the rotation of the output shaft of the rotary actuator 4 and transmits it to the arm 5.

  Each arm 5 is attached to the corresponding speed reducer unit 10 at its base end, and is thereby rotatably connected to the base 2. The axis of rotation A0 of the arm 5 with respect to the base 2 is arranged 120-degree rotationally symmetrically on the same plane and intersects so as to form an equilateral triangle. In the present embodiment, the three rotation axes A0 are arranged rotationally symmetrically on the same horizontal plane.

  The three links 6 connect the tip portions of the three arms 5 to the single movable plate 3. Each link 6 is connected to the distal end portion of the corresponding arm 5 via the first joint portion 7 at the base end portion, and can be rotated to the movable plate 3 via the second joint portion 8 at the distal end portion. Connected. The first joint portion 7 is rotatable about two axes, a first axis A1 parallel to the rotation axis A0 with respect to the base 2 of the arm 5 and a second axis A2 perpendicular to the first axis A1. The proximal end portion is connected to the distal end portion of the arm 5. The second joint portion 8 is configured so that the distal end portion of the link 6 can be rotated around two axes of a third axis A3 parallel to the first axis A1 and a fourth axis A4 perpendicular to the third axis A3. Connect to The three fourth axes A4 are arranged in a 120-degree rotational symmetry on the same plane, intersect so as to form an equilateral triangle, and the plane is parallel to the plane on which the three rotation axes A0 are located.

  According to the robot 1 configured as described above, one link 6 is rotatably connected to the arm 5 with a rotational freedom of two orthogonal axes at the base end portion, and two orthogonal axes at the distal end portion. The movable plate 3 is rotatably connected with a degree of freedom of rotation. For any operation of the three rotary actuators 4, the plane on which the fourth axis A4 is located maintains a parallel state with respect to the plane on which the rotation axis A0 is located, so that the attitude of the movable plate 3 with respect to the base 2 does not change. In this way, the end effector can be moved three-dimensionally while keeping the posture of the movable plate 3 with respect to the base 2 constant (horizontal in the present embodiment) while the total number of links 6 is three.

  In the robot 1, when maintaining the above parallel state, the roles of the two joint portions 7 and 8 (joint structures for four axes per link 6) corresponding to the three links 6 are large. It becomes. Therefore, in the first and second joint portions 7 and 8 according to the present embodiment, special consideration is given so that rattling does not occur in each of the joint structures for four axes, as will be described later.

  Since the above-described links 6 are configured as one set, the base end portion of the link 6 can be cantilevered by the distal end portion of the arm 5 via the first joint portion 7. The distal end portion of the link 6 can also be cantilevered by the movable plate 3 via the second joint portion 8. For this reason, when paying attention to the first joint portion 7, it is difficult to interfere with the distal end portion of the arm 5 when the base end portion of the link 6 rotates around the first axis A <b> 1 or around the second axis A <b> 2. The same applies to the second joint portion 8, and the link 6 is unlikely to interfere with the movable plate 3 when the distal end portion of the link 6 rotates around the third axis A3 or around the fourth axis A4. If the cantilever support structure is adopted in this way, the rotation range of the link 6 is expanded as compared with a case where both ends of the link are supported on both ends like a cardan joint or the like. Accordingly, the movable range of the end effector can be expanded without increasing the size of the entire robot, or the entire robot can be reduced without reducing the movable range of the end effector. The realization of cantilever support will be described in detail below.

  FIG. 2 is a skeleton diagram of the link 6, the first joint portion 7, and the second joint portion 8 shown in FIG. FIG. 3 is a perspective view showing a peripheral portion of the first joint portion 7 shown in FIG. The second joint portion 8 is substantially the same as the configuration of the first joint portion 7, and thus a detailed description thereof is omitted as appropriate. As shown in FIG. 2, the first joint portion 7 includes a first rotating shaft 11 that rotates around the first axis A <b> 1 with respect to the tip end portion of the arm 5, and a second axis A <b> 2 around the first rotating shaft 11. And a base end portion of the link 6 is fixed to the second rotary shaft 12. As described above, the first axis A1 is parallel to the rotation axis A0 with respect to the base 2 of the arm 2, and the second axis A2 is perpendicular to the first axis A1.

  The first rotating shaft 11 has a rotatable first shaft portion 13, and the first shaft portion 13 is rotatably supported by a first bearing 14. The first bearing 14 is provided on the outer peripheral side of the first shaft portion 13 and is held by a first bearing holder 15 provided further on the outer peripheral side thereof. The first bearing holder 15 holds the first bearing 14 and is fixed to the distal end portion of the arm 5 with the first bearing 14 supporting the first shaft portion 13 (see FIG. 3).

  The second rotating shaft 12 has a rotatable second shaft portion 16, and the second shaft portion 16 is rotatably supported by a second bearing 17. The 2nd bearing 17 is provided in the outer peripheral side of the 2nd axial part 16, and is hold | maintained by the 2nd bearing holder 18 provided in the further outer peripheral side. The second bearing holder 18 is provided at the end of the first shaft portion 13.

  The second rotating shaft 12 has a protruding end 19 that continuously protrudes from the second bearing 16 from the second shaft portion 16, and the base end of the link 6 is fixed to the protruding end 19. In this embodiment, the base end portion of the link 6 is formed in a cylindrical shape, and one protruding end portion 19 is fitted to the base end portion of the link 6 so as not to rotate (see FIG. 3).

  FIG. 4 is a cross-sectional view showing the internal structure of the first joint portion 7 shown in FIG. As shown in FIG. 4, the arm 5 has a receiving hole 21 for partially receiving the first joint portion 7 at a tip portion thereof. The receiving hole 21 extends in parallel with the rotation axis A0 (see FIGS. 1 and 2), and the central axis of the receiving hole 21 coincides with the first axis A1. The receiving hole 21 has a receiving opening 22 at one end thereof, and the first bearing holder 15 is fitted into the receiving hole 21 through the receiving opening 22 and is removed from the arm 5 using a joint attaching / detaching tool 23 such as a bolt. Fixed as possible.

  The first bearing holder 15 includes a cylindrical holder body 24 and a holder cover 25 attached to the holder body 24. The holder body 24 is provided with a bearing insertion port 26, and the first bearing 14 is inserted into the holder body 24 through the bearing insertion port 26 toward one side in the axial direction, and the bearing insertion port 26 is then inserted into the holder cover. 25. The outer ring 14 b of the first bearing 14 is fixed to the inner peripheral surface of the holder body 24. The holder body 24 has a protrusion 24a protruding from the inner peripheral surface, the holder cover 25 has a protrusion 25a protruding into the holder body 24 through the bearing insertion port 26, and the outer ring 14a has the protrusion 24a, 25a is sandwiched in the axial direction.

  The first shaft portion 13 passes through the holder cover 25 and enters the first bearing holder 14 and is inserted into the inner ring 14 b of the first bearing 14, and the inner ring 14 b is fixed to the outer peripheral surface of the first shaft portion 13. The A stopper portion 27 having a diameter larger than the inner diameter of the inner ring 14b is provided at the other end portion in the axial direction of the first shaft portion 13 (end portion on the near side in the shaft entry direction). Therefore, when the first shaft portion 13 is inserted into the inner ring 14b, the stopper portion 27 comes into contact with the other end surface in the axial direction of the inner ring 14b (the front end surface in the shaft entry direction), and the first shaft portion 13 stops entering. The holder body 24 has an access port 28 at the end opposite to the bearing insertion port 26 in the axial direction (the end on the back side in the shaft entry direction), and the first bearing 14 is connected to the first bearing 14 via the access port 28. It is accessible from. Using the access port 28, a presser portion 29 is installed on one end surface in the axial direction of the inner ring 14b (back end surface in the shaft entry direction), a bolt 30 is inserted into the presser portion 29, and the inserted bolt 30 is the first one. The first shaft 13 is screwed to the other end in the axial direction (back end of the shaft entering direction). As a result, the inner ring 14 b is sandwiched between the stopper portion 27 and the pressing portion 29 in the axial direction.

  The first bearing 14 according to the present embodiment includes two tapered roller bearings assembled on the back surface, and these two tapered roller bearings are arranged in the axial direction in a state where the outer rings are in contact with each other in the axial direction. ing. For this reason, when the tightening torque of the bolt 30 is increased, the first shaft portion 13 tries to enter toward the one side in the axial direction (back side in the shaft entry direction) by the action of the screw pair, and the stopper portion 28 and the holding member 29 The interval is about to shrink. Therefore, backlash in the first bearing 14 can be eliminated, or a preload can be applied to the first bearing 14.

  The second bearing holder 18 is provided on the side opposite to the first shaft portion 13 as viewed from the stopper portion 27, that is, on the other end side in the axial direction of the stopper portion 28 (front side in the shaft entry direction). Then, the first shaft portion 13 and the stopper portion 27 are integrally formed. The second bearing holder 18 is disposed away from the first bearing holder 15 in the axial direction, and the second bearing holder 18 is located at any angular position around the first rotational axis A1. The holder 18 does not interfere with the first bearing holder 15.

  The second bearing holder 18 is formed in a cylindrical shape extending perpendicular to the axis of the first shaft portion 13 (that is, the first rotation axis A1). The 2nd bearing holder 18 has the bearing insertion ports 31 and 32 provided in the axial direction one end part and the other end part, respectively, and the convex part 33 which protrudes from the axial direction center part of an internal peripheral surface. Similar to the first bearing 14, the second bearing 17 according to the present embodiment is composed of two tapered roller bearings assembled on the back surface. One bearing 17A is inserted into the second bearing holder 18 from the bearing insertion port 31 at one end, and the other bearing 17B is inserted into the second bearing holder 18 from the bearing insertion port 32 at the other end. The outer rings 17Aa and 17Ba of both the bearings 17A and 17B abut against the convex portion 33 and are fixed to the inner peripheral surface of the second bearing holder 18.

  The second shaft portion 16 enters the second bearing holder 18 from the other axial side toward the one axial side, and is inserted in this order into the inner ring 17Bb of the other bearing 17B and the inner ring 17Ab of the one bearing 17A. Rarely, both inner rings 17Bb and 17Ab are fixed to the outer peripheral surface of the second shaft portion 16. One end of the second shaft portion 16 (end portion on the back side in the shaft entry direction) protrudes from the inner ring 17Ab of one bearing 17A and forms the above-described protruding end portion 19.

  In the present embodiment, the protruding end portion 19 is formed only at one end portion of the second shaft portion 16 (the end portion on the back side in the shaft entry direction). A stopper portion 34 having a larger diameter than the inner diameter of the other inner ring 17Ab is provided at the other end portion (the end portion on the near side in the shaft entry direction) of the second shaft portion 16. Therefore, when the second shaft portion 16 is inserted into the inner rings 17Ab and 17Bb, the stopper portion 34 comes into contact with the other end surface in the axial direction of the other inner ring 17Bb (the front end surface on the front side in the shaft entry direction) and The entry stops. On the other hand, as described above, the projecting end portion 19 is fitted into the base end portion of the link 6, and the base end portion of the link 6 is fixed to the projecting end portion 19 (that is, the second rotating shaft 12). For this fixing, the female screw 35 may be screwed into the proximal end portion of the link 6 and the outer peripheral surface of the protruding end portion 19 may be pressed by the distal end of the female screw 35.

  The base end portion of the link 6 has a pair of side surfaces in the axial direction, and one of the side surfaces (the end surface in the axial entry direction) is located on one side in the axial direction with respect to the tip of the protruding end portion 19. The side surface (the end surface on the near side in the shaft entry direction) abuts on one end surface in the axial direction (the end surface on the back side in the shaft entry direction, the front end surface in the bearing insertion direction) of one inner ring 17Ab. Here, “contact” includes not only the case where the end surfaces are in direct contact with each other but also the case where other members are interposed between the end surfaces and these end surfaces sandwich the other members.

  A pressing member 36 is installed on one side surface of the link 6, and a bolt 37 is inserted into the pressing member 36 from one side in the axial direction to the other side. The inserted bolt 37 is a protruding end (that is, a first end). It is screwed to one end of the biaxial portion 16 (the end on the back side in the shaft entry direction). Accordingly, the inner ring 17Ab and the inner ring 17Bb are sandwiched between the stopper portion 36 and the pressing portion 37 in the axial direction.

  As described above, the second bearing 17 is composed of two angular bearings assembled on the back surface. For this reason, when the tightening torque of the bolt 37 is increased, the second shaft portion 16 tries to enter toward one side in the axial direction (back side in the shaft entering direction) by the action of the screw pair, and the stopper portion 36 and the holding portion 37 Axial spacing is about to shrink. Therefore, play in the second bearing 17 can be eliminated, or a preload can be applied to the second bearing 17.

  The second joint portion 8 will be briefly described. As shown in FIG. 2, the second joint portion 8 includes a third rotating shaft 41 that rotates around the third axis A3 together with the distal end portion of the link 6, and a third rotating shaft. 41, and a fourth rotating shaft 42 that rotates about the fourth axis A4. The fourth rotating shaft 42 is rotatably connected to the movable plate 3. Thereby, the front-end | tip part of the link 6 is connected with the movable plate 3 so that rotation is possible to the surroundings of two axes of 3rd axis line A3 and 4th axis line A4. As described above, the third axis A3 is parallel to the second axis A2, and the fourth axis A4 is perpendicular to the third axis A3.

  The third rotating shaft 41 has the same structure as the second rotating shaft 12 and is supported in the same manner as the second rotating shaft 12. The fourth rotating shaft 42 has the same structure as the first rotating shaft 11 and is supported in the same manner as the first rotating shaft 11. The third rotating shaft 41 is supported by a third bearing 43, the third bearing 43 is held by a third bearing holder 44, and the relationship of the third bearing holder 44 to the fourth rotating shaft 42 is that of the second bearing holder 18. The relationship is the same as for the one-rotation shaft 11. The fourth rotating shaft 42 is supported by a fourth bearing 45, the fourth bearing 45 is held by a fourth bearing holder 46, and the fourth bearing holder 46 has the same structure as the first bearing holder 15. The end portion of the third rotating shaft 41 also protrudes from the third bearing holder 44 in the same manner as the second rotating shaft 12, and the tip end portion of the link 6 is fixed thereto. The link 6 has two attachment holes for fitting the second rotary shaft 12 and the third rotary shaft 41 at one end and the other end, respectively. Since the second axis A2 is parallel to the third axis A3, these two mounting holes extend in parallel to each other.

  FIG. 5 is a partially exploded perspective view showing the link 6 shown in FIG. 1 in an exploded manner. As shown in FIG. 5, in assembling the robot 1, the link 6 is assembled in advance with the first joint portion 7 and the second joint portion 8. Thereby, the link assembly 50 including the link 6, the first joint portion 7, and the second joint portion 8 is configured. When the link assembly 50 is configured, the second axis A2 is parallel to the third axis A3, the second axis A2 is perpendicular to the first axis A1, and the fourth axis A4 is the third axis A3. It becomes perpendicular to. When the link assembly 50 is configured, the second rotary shaft 12 can freely rotate with respect to the first rotary shaft 11, and the first bearing holder 15 can be rotated with respect to the link 6 around the second axis A <b> 2. Relative rotation freely. The fourth bearing holder 46 also freely rotates relative to the link 6 around the third axis A3.

  On the other hand, as described above, the arm 5 has the receiving hole 21 for partially receiving the first joint portion 7 at the tip thereof. The movable plate 3 has three link connecting portions 51 connected to the three links 6. These link connecting portions 51 project radially from the central portion of the movable plate having the structure 3a for attaching the end effector, and are arranged in a 120-degree rotational symmetry. Each link connecting portion 51 has a receiving hole 52 that partially receives the second joint portion 8 at the tip portion thereof.

  The link assembly 50 is brought to the side of the arm 5 and the movable plate 3, the first joint portion 7 is positioned beside the receiving hole 21 of the arm 5, and the second joint portion 8 is positioned beside the receiving hole 52 of the movable plate 3. To be located. At this time, the link assembly 50 and the movable plate 3 are roughly positioned with respect to the arm 5 so that the receiving hole 52 is positioned on the same side as the receiving hole 21 when viewed from the link 6. Next, the first bearing holder 15 and the fourth bearing holder 46 are rotated with respect to the link 6 as necessary, so that the first bearing holder 15 and the fourth bearing holder 46 are directed in substantially the same direction. Then, the first bearing holder 15 is inserted into the receiving hole 21, and the fourth bearing holder 46 is inserted into the receiving hole 52. At this time, the second bearing holder 18 is exposed from the arm 5, and the third bearing holder 43 is exposed from the movable plate 3. Next, the first bearing holder 15 is fixed to the arm 5, and the fourth bearing holder 46 is fixed to the joint connecting portion 51. As a result, the link 6 is connected to the arm 5 via the first joint portion 7 and is connected to the movable plate 3 via the second joint portion 8.

  Returning to FIG. 1, a part of the first joint portion 7 (for example, the first bearing holder) is embedded in the arm 5, and the remaining portion (for example, the second bearing holder) is installed on one side of the arm 5. The A part of the second joint portion 8 (for example, a fourth bearing holder) is embedded in the link connecting portion 51, and the remaining portion (for example, the third bearing holder) is installed on the link connecting portion 51. The link 6 extends in a generally vertical direction on the side of the arm 5 and the side of the link connecting portion 51 immediately next to the one side.

  Thus, in the robot 1 according to this embodiment, the base end portion of the link 6 is cantilevered by the arm 5 via the first joint portion 7, and the tip end portion of the link 6 is movable via the second joint portion 8. The plate 3 is cantilevered. For this reason, when paying attention to the first joint portion 7, it is difficult to interfere with the distal end portion of the arm 5 when the base end portion of the link 6 rotates around the first axis A <b> 1 or around the second axis A <b> 2. The same applies to the second joint portion 8, and the link 6 is unlikely to interfere with the movable plate 3 when the distal end portion of the link 6 rotates around the third axis A3 or around the fourth axis A4. As a result, when the size of the entire robot is the same, the rotation range of the link 6 is increased in the robot 1 according to the present embodiment compared to the case where both ends of the link are supported at both ends, such as a cardan joint. To do. Accordingly, the movable range of the end effector can be expanded without increasing the size of the entire robot, or the entire robot can be reduced without reducing the movable range of the end effector.

  In order to move the movable plate 3 while maintaining the posture of the movable plate 3 with respect to the base 2, both the first joint portion 7 and the second joint portion 8 are required to have two degrees of freedom of rotation of orthogonal axes. In the present embodiment, in order to realize cantilever support of each link 6, in the first joint portion 7, the two rotary shafts 11 and 12 that can rotate independently of each other intersect the T-shape or the L-shape. Placed in. By adopting such a structure, only one rotary shaft (first rotary shaft 11) is rotatably connected to the arm 5, and the other rotary shaft (second rotary shaft 12) is fixed to this. The base end portion of the link 6 can be easily projected to the outer piece side of the arm 5. Thereby, the cantilever support of the base end part of the link 6 is implement | achieved. The second joint portion 8 is also configured in the same manner as the first joint portion 7, and only one rotary shaft (fourth rotary shaft 42) is rotatably connected to the link connecting portion 51, and the other rotary shaft (first 3 rotation shaft 41) and the front-end | tip part of the link 6 fixed to this can be easily protruded to the outer piece side of the link connection part 51. FIG. Thereby, the cantilever support of the front-end | tip part of the link 6 is implement | achieved.

  Further, the one side surface of the arm 5 is directed in the substantially same direction as the one side surface of the link connecting portion 51. For this reason, the link assembly 50 is held on the same side when viewed from the arm 5 and the link connecting portion 51, and the link 6 protrudes on the same side when viewed from the arm 5 and the link connecting portion 51. In other words, if the arm 5, the link 6 and the link connecting portion 51 are traced from above, a U-shape can be drawn, and the link assembly 50 is not arranged to draw a Z-shape. Therefore, coupled with the fact that the link 6 is cantilevered, the rotation range of the link 6 can be further increased.

  Further, the insertion direction of the first bearing holder 15 into the arm 5 coincides with the insertion direction of the fourth bearing holder 46 into the link connecting portion 51. Naturally, the removal direction of the first bearing holder 15 from the arm 5 coincides with the removal direction of the fourth bearing holder 46 from the link connecting portion 51. For this reason, the link assembly 50 can be easily attached to or detached from the arm 5 and the movable plate 3.

  Further, when the link 6 is attached to and detached from the arm 5 and the movable plate 3, both the first joint part 7 and the second joint part 8 are attached and detached. Therefore, the assembly and disassembly of the first joint portion 7 and the second joint portion 8 with respect to the link 6 can be performed at a place away from the work space of the robot 1, and the link 6, the first joint portion 7 and the first joint portion 7 can be performed. Maintenance work efficiency of the two joint portion 8 is improved.

  FIG. 6 is a perspective view showing a link 106 according to a modification. As shown in FIG. 6, if the base end of the link 106 is cantilevered by the arm 5 (not shown in FIG. 6, refer to FIG. 1 etc. as appropriate), the second rotating shaft 112 is supported at both ends. It may be. If the tip of the link 106 is also cantilevered by the movable plate 3 (not shown in FIG. 6; see FIG. 1 or the like as appropriate), the third rotating shaft 141 may be supported at both ends.

  When paying attention to the first joint portion 107, a pair of fixing pieces 106a divided into two forks are provided at the base end portion of the link 6, and the second rotating shaft 112 is protruded from the second bearing holder 118 to both sides, so that the pair of fixing pieces 106a. May be respectively fixed to the two protruding end portions. In this case, the pair of fixed pieces 106a are arranged so as to sandwich the second bearing holder 118 in the direction of the second axis A2. In the case of supporting both ends in this way, when the link 6 rotates around the second axis A2, the pair of fixed pieces 106a easily interfere with the first bearing holder 115. Therefore, the pair of fixed pieces 106a is preferably provided with a notch 106b so as to be away from the first bearing holder 115 from the end surface proximal to the first bearing holder 115. By providing the notch 106b in this manner, both the support of the second rotating shaft 112 by the link 6 and the widening of the rotation range around the second axis A2 of the link 6 can be achieved.

  Since the 2nd joint part 108 is the same as this, the detailed description which overlaps is abbreviate | omitted. In FIG. 6, reference numeral 106 c is a pair of fixing pieces that are bifurcated at the tip of the link 106, reference numeral 144 is a third bearing holder similar to that in the above embodiment, and reference numeral 146 is the same as that in the above embodiment. A four-bearing holder, symbol 106d, is a notch provided in the fixed piece 106c.

  FIG. 7 is an exploded perspective view showing a peripheral portion of the rotary actuator 4 shown in FIG. As shown in FIG. 7, the robot 1 includes three rotary actuators 4, and the speed reducer unit 10 and the arm 5 are sequentially connected to each rotary actuator 4 in this order. In assembling the robot 1, the rotary actuator 4 is assembled in advance with the speed reducer unit 10 and the arm 5. Thereby, three sets of actuator assemblies 60 including the rotary actuator 4, the reduction gear unit 10, and the arm 5 are configured.

  Next, these actuator assemblies 60 are detachably coupled to the base 2 and arranged in a 120-degree rotational symmetry. In this embodiment, the speed reducer unit 10 is directly coupled to the base 2 and the rotary actuator 4 is coupled to the base 2 via the speed reducer unit 10, but this is merely an example, and the speed reducer The unit 10 can be omitted as appropriate, and the rotary actuator 4 may be directly coupled to the base 2 regardless of whether or not the speed reducer unit 10 is provided.

  The three sets of actuator assemblies 60 are coupled to the outer bottom surface of the base 2. The actuator assembly 60 (the speed reducer unit 10 in the present embodiment) has an actuator opening 61 at the top, and the base 2 has three base side openings 62 at the bottom. Each actuator assembly 60 is detachably coupled to the outer bottom surface of the base 2 so that the actuator openings 61 are connected to the corresponding base openings 62. An access port 63 for accessing the inside of the base 2 is provided in the upper part of the base 2. In the present embodiment, the base 2 has three access ports 63, and these access ports 63 are arranged so as to overlap the base opening 62 in plan view. For this reason, it is possible to access not only the inside of the base 2 but also the base opening 62 and the actuator opening 62 connected thereto by using the access port 63. As a result, the actuator assembly 60 can be accessed through these openings 61 and 62. Internal access is also possible. Various electronic parts for controlling and operating the rotary actuator 4 are accommodated in the base 2. When the access port 63 is used, maintenance work of the actuator assembly 60 such as connection work between the actuator assembly 60 attached to the base 2 and the electronic component can be easily performed.

  With reference to FIGS. 5 and 7, the robot 1 according to this embodiment includes a base 2, three sets of actuator assemblies 60, three sets of link assemblies 50, and the movable plate 3. Three sets of actuator assemblies 60 and three sets of link assemblies 50 are assembled in advance, three sets of actuator assemblies 60 are assembled to the base 2, and three sets of link assemblies 50 are combined with three sets of actuator assemblies 60 and the movable plate 3. When assembled to the robot 1, the robot 1 is completed.

  It is assumed that maintenance work for one first joint portion 7 is necessary in a state where the robot 1 is completed. In this case, it is only necessary to remove a set of link assemblies 50 including the first joint portion 7. As described above, the efficiency of the work of removing the link assembly 50 and the maintenance work of the first joint portion 7 is good. When one set of link assemblies is removed, the movable plate 2 can be kept connected to the base 2 via the remaining two sets of link assemblies 50. For this reason, the maintenance of only the first joint part does not cause the robot to be disassembled apart, and the reassembly work after the maintenance is also simplified. As described above, the work of assembling one link assembly 50 is efficient.

  It is assumed that maintenance work for one reduction gear unit 10 is required in a state where the robot 1 is completed. In this case, it is only necessary to remove the actuator assembly 60 including the reduction gear unit 10 after removing the link assembly 50 connected to the reduction gear unit 10. The efficiency of the maintenance work and the reassembly work is improved as in the case of performing the maintenance work of the joint portion 7.

  Although the embodiment has been described so far, the above configuration is merely an example, and can be appropriately added, changed, and deleted without departing from the spirit of the present invention.

  The present invention can expand the movable range of the end effector without increasing the size of the robot, or can reduce the size of the robot without reducing the movable range of the end effector. It is beneficial to apply.

A0 Axis of rotation relative to the arm base A1 First axis A2 Second axis A3 Third axis A4 Fourth axis 1 Parallel link robot 2 Base 3 Movable plate 5 Arm 6, 106 Link 7, 107 First joint part 8, 108 Second joint portion 11 First rotation shaft 12 Second rotation shaft 14 First bearing 15, 115 First bearing holder 17 Second bearing 18, 118 Second bearing holder 41 Third rotation shaft 42 Fourth rotation shaft 43 Third bearing 44, 144 Third bearing holder 45 Fourth bearing 46, 146 Fourth bearing holder 50, 150 Link assembly 60 Actuator assembly

Claims (1)

A base, a movable plate to which an end effector is attached, three arms that are rotatably connected to the base, and three links that respectively connect the distal ends of the arms to the movable plate. ,
The link is rotatably connected to a distal end portion of the arm via a first joint portion at a base end portion thereof, and is connected to the movable plate via a second joint portion at a distal end portion thereof.
The first joint portion is configured to be rotatable about two axes of a first axis parallel to a rotation axis of the arm with respect to the base and a second axis perpendicular to the first axis. To the tip of the arm, and the second joint portion is rotatable about two axes, a third axis parallel to the first axis and a fourth axis perpendicular to the third axis. Connecting the tip of the link to the movable plate;
The base end portion of the link is cantilevered by the tip end portion of the arm via the first joint portion, and the tip end portion of the link is pieced to the movable plate via the second joint portion. Supported,
The first joint portion includes a first bearing, a first bearing holder that holds the first bearing, and a first rotating shaft that is inserted into the first bearing and supported rotatably around the first axis. The base end portion of the link is connected to one end portion of the first rotating shaft so as to be rotatable around the second axis,
The second joint portion includes a fourth bearing, a fourth bearing holder that holds the fourth bearing, a fourth rotating shaft that is inserted into the fourth bearing and is rotatably supported around the fourth axis. The tip of the link is connected to one end of the fourth rotating shaft so as to be rotatable around the third axis,
The first bearing holder is fitted into a receiving hole formed in the arm and is detachably fixed to the arm, and the fourth bearing holder is fitted into a receiving hole formed in the movable plate. removably are fixed, the insertion direction into the receiving hole of the arm of the first bearing holder, that matches the direction of insertion into the movable plate said receiving hole of said fourth bearing holder, parallel links robot.

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