JP2019063902A - Articulated robot and its operation method - Google Patents

Abstract

To provide an articulated robot which can accurately perform work for making an article gripped by an end effector contact with a workpiece arranged at a fixed position without receiving an influence of the positional displacement of the article and the workpiece, and its operation method.SOLUTION: An articulated robot 1 comprises: a first arm 3 which can turn around an axial core C1 in a vertical direction; a second arm 4 which can turn around an axial core C2 in the vertical direction; and an end effector operation mechanism 7 for supporting the end effector so as to be turnable or changeable in a posture, or to be turnable and changeable in a posture around the axial core in the vertical direction. At least one of actuators of a first arm actuator 11, a second arm actuator 12 and end effector operation mechanism actuators 13, 31 comprises a clutch mechanism which can block the transmission of reversely-inputted torque applied to an output side to a rotation drive part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an articulated robot used for processing, transfer, assembly and the like of articles in various industrial fields, and an operation method thereof.

  There is a horizontal articulated robot in which an arm operates in the horizontal direction, a so-called SCARA robot, which is a kind of the articulated robot (for example, Patent Documents 1 to 3). In addition, there is a robot arm type articulated robot which has a plurality of rotary joints and operates close to a human arm (for example, Patent Documents 4 and 5).

Unexamined-Japanese-Patent No. 9-19835 JP, 2010-284726, A JP, 2011-20188, A JP 2003-311667 A JP, 2016-209940, A

  The applicant has proposed a SCARA robot having a first arm 3 and a second arm 4 as shown in FIG. 21 and provided with a parallel link mechanism 5 at the tip of the second arm 3 (Japanese Patent Application 2017-65605). The parallel link mechanism 5 can be rotated about the axis O3 by the rotation mechanism 310, and can be moved up and down along the axis O3 by the elevation mechanism 311. According to this proposed configuration, it is possible to change the attitude of the end effector 300 attached to the parallel link mechanism 5 to an arbitrary angle, and the end effector 300 can perform complicated work.

  However, in the proposed configuration, for example, as illustrated in FIG. 21, it is difficult to insert the article 301 gripped by the end effector 300 into the oblique hole 302 a of the workpiece 302 provided at the fixed position. That is, in order to insert the article 301 into the hole 302 a, the end effector 300 can be inserted into the article 301 while maintaining the posture of the end effector 300 by the parallel link mechanism 5 such that the central axis of the article 301 coincides with the central axis of the hole 302 a. It is necessary to move diagonally along the central axis of and the central axis of the hole 302a. In order to do so, the operations of the first arm 3, the second arm 4, the parallel link mechanism 5, the rotation mechanism 310, and the elevation mechanism 311 have to be finely controlled, which is very difficult to control.

  Therefore, in addition to the configuration proposed above, the applicant of the present invention mounted a 1-axis linear motion mechanism on the parallel link mechanism 5 and tried to attach the end effector 300 to the 1-axis linear motion mechanism. When the single-axis linear motion mechanism is provided, the first effector 3, the second arm 4, the parallel link mechanism 5, the rotation mechanism 310, and the lifting mechanism 311 are not operated, and the single-axis linear motion mechanism advances and retracts the end effector 300 Control can be simplified because the article 301 can be inserted into the hole 302 a of the work 302 alone.

  As a one-axis linear motion mechanism used for the SCARA robot, adoption of slide screw structure is being studied for weight reduction, simplification, and cost reduction. However, if it is a slide screw structure, the slide screw There is a concern about the effects of backlash in the department. That is, there is a possibility that the article 301 can not smoothly insert the article 301 into the hole 302a when the article 301 strikes the inner wall of the hole 302a due to a shift between the feeding direction of the article 301 by the linear translation mechanism and the direction of the hole 302a. is there. In order to adopt a slide screw structure as a one-axis linear motion mechanism, it is necessary to take measures against the influence of the above-mentioned backlash.

  In addition, the applicant has attempted to use a SCARA robot to insert an article into an upward hole of a workpiece conveyed by a belt conveyor. Specifically, an elevating mechanism is provided at any part of the SCARA robot, and the elevating mechanism lowers the end effector for gripping the article to insert the article into the hole of the work on the belt conveyor. However, in conveyance by a belt conveyor, a work may move by vibration at the time of conveyance. When the workpiece moves, the positional relationship between the article and the workpiece is deviated, and the article can not be inserted into the hole of the workpiece.

  Patent Document 1 proposes a robot assembling apparatus capable of eliminating an error when incorporating an article held by a SCARA robot into a work in assembling an article using the SCARA robot. In this robot assembly apparatus as well, after moving the pins (articles) held by the SCARA robot to the predetermined planar view position by operating the arms, the pins are lowered together with the arms to move them on the work table. Insert the pin into the hole of the work. In this proposal, the worktable is movable in the X-axis direction and the Y-axis direction along the horizontal plane. As a result, when inserting a pin into the hole of the work, if there is a gap between the hole of the work and the pin, the work moves along the pin as the pin is lowered in the Z-axis direction. Deviation can be absorbed.

  However, since the structure of the said patent document 1 needs the mechanism which supports a work bench so that a work bench may move according to a pin, the subject that the whole apparatus becomes expensive occurs.

It is an object of the present invention to accurately perform an operation performed by bringing an article held by an end effector into contact with a work provided at a fixed position without being affected by the positional deviation between the article and the work. It is providing a joint robot.
Another object of the present invention is to provide a method of operating the above-described articulated robot capable of performing an operation of inserting an article into a hole of a workpiece without being affected by the positional deviation between the article and the workpiece. .

The articulated robot according to the present invention comprises a first arm provided on a support and rotatable about an axis in the vertical direction, an actuator for a first arm for rotating the first arm, and a tip of the first arm. And an actuator for the second arm that rotates the second arm, and an end effector provided at the tip of the second arm about the vertical axis. And an end effector operation mechanism for operating the end effector operation mechanism, and an end effector operation mechanism capable of supporting either or both of the position change and the posture change,
At least one of the first arm actuator, the second arm actuator, and the end effector operation mechanism actuator can interrupt transmission of the reverse input torque applied to the output side to the rotational drive unit Clutch mechanism is provided.

  In this articulated robot, the clutch mechanism is always in the connected state. In this state, the first arm and the second arm are rotated to change the planar view position of the end effector, and the end effector operation mechanism is operated to perform either or both of rotation and attitude change of the end effector Work with the end effector. At this time, when an external force is applied to the end effector, the clutch mechanism provided in at least one of the first arm actuator, the second arm actuator, and the end effector operation mechanism actuator is brought into the disconnection state. As a result, the reverse input torque is not transmitted to the rotational drive unit of the actuator. Therefore, the operation target operated by the actuator having the clutch mechanism, that is, any of the first arm, the second arm, and the end effector operation mechanism can freely move, and the operation target is fixed. We can eliminate bad effects.

  In the present invention, the end effector operating mechanism includes a rotational two degree of freedom mechanism for changing the attitude of the distal end side member to the proximal end member provided at the distal end of the second arm, and the rotational two degree of freedom mechanism And a linear actuator mechanism provided on the distal end side member for advancing and retracting the end effector in one axial direction, and the actuator for the end effector operating mechanism operates the rotational two degree of freedom mechanism, and the end effector The clutch mechanism may be provided on the actuating mechanism actuator.

  In this configuration, since the end effector operation mechanism has a rotational two degree of freedom mechanism and a single-axis linear movement mechanism, it is possible to set the end effector's posture to an arbitrary angle by the rotational two degree of freedom mechanism. The movement mechanism can move the end effector back and forth in one axial direction. As a result, for example, the work of inserting the article gripped by the end effector into the hole of the work provided at the fixed position can be performed only by operating the one-axis linear motion mechanism, so control is easy.

When changing the attitude of the end effector, the actuator for the end effector operation mechanism is in a clutch connection state, and the rotation two degrees of freedom mechanism is operated. When the position and posture of the end effector are determined and the 1-axis linear motion mechanism is actuated to insert an article into the hole of the work, the actuator for the end effector actuation mechanism is in the clutch disengaged state, and to the rotary drive of the actuator Make sure that the reverse input torque is not transmitted. As a result, the rotational two degree of freedom mechanism can freely move according to the external force. For this reason, even if the moving direction of the article is slightly deviated with respect to the direction of the central axis of the hole due to the structural problem of the single-axis linear movement mechanism, the mechanism with two degrees of freedom of rotation according to the force received from By moving the object, the article can be inserted into the hole of the work by absorbing the deviation.
Thus, since a slight deviation in the feed direction due to the single-axis linear movement mechanism can be tolerated, as a single-axis linear movement mechanism, a mechanism that may cause a structural deviation in the feed direction, such as a slide screw mechanism It can be used. The slide screw mechanism is a relatively lightweight and simple structure, and can be manufactured at low cost.

  The rotation two-degree-of-freedom mechanism connects the proximal end link hub, which is the proximal end member, with the distal link hub, which is the distal end member, so that its attitude can be changed via three or more sets of link mechanisms. And each of the link mechanisms includes a proximal end and a distal end end link member rotatably connected at one end to the proximal end link hub and the distal end link hub, and the proximal end and the proximal end link member. It may be a parallel link mechanism having a center link member rotatably connected at both ends to the other end of the tip end side end link member. In that case, the actuator for the end effector operating mechanism causes the link hub on the proximal end side to arbitrarily change the posture of the link hub on the distal end side with respect to the link hub on the proximal end in two or more link mechanisms among the three or more link mechanisms. Is provided.

  The parallel link mechanism includes a proximal end link hub, a distal end link hub, and three or more sets of link mechanisms. The distal end link hub can rotate about two orthogonal axes with respect to the proximal end link hub. Constitute a two-degree-of-freedom mechanism. This two-degree-of-freedom mechanism can widen the movable range of the distal end side link hub while being compact. Therefore, the end effector can be changed to any posture. In addition, since the parallel link mechanism is compact, the load on the first arm and the second arm is small, and the rigidity of these arms and their supporting portions can be suppressed low. When the end effector operation mechanism actuator is provided in two or more link mechanisms among the three or more link mechanisms, the attitude of the distal end side link hub can be determined.

  A first method of operating an articulated robot according to the present invention is the method of operating the articulated robot in a case where an article gripped by an end effector is inserted into a hole of a work provided at a fixed position. Specifically, the first arm, the second arm, and the end effector operation mechanism are operated so that the central axis of the article coincides with the central axis of the hole of the workpiece, and the tip of the article is the same. After positioning so as to be located near the entrance of the hole of the work, with the clutch mechanism of the actuator for the end effector operation mechanism shut off, the one-axis linear motion mechanism is operated to put the article into the hole of the work insert.

  According to this operation method of the articulated robot, the end effector is moved in one axial direction by the one-axis linear motion mechanism, and the clutch mechanism is brought into the disconnected state when inserting the article gripped by the end effector into the hole of the work. Allow the two-degree-of-rotation mechanism to move freely. By this, even if the moving direction of the article is slightly deviated with respect to the direction of the central axis of the hole, the above-mentioned deviation is absorbed by the movement of the two rotational degrees of freedom mechanism according to the force received from the inner wall of the hole. Can be inserted into the hole of the work.

  In the present invention, it has an elevating mechanism for raising and lowering at least one of the first arm, the second arm, and the end effector operation mechanism, and the actuator for the first arm and the actuator for the second arm have the elevating mechanism. A clutch mechanism may be provided.

According to this configuration, the first arm and the second arm are rotated to determine the planar view position of the end effector, and the lifting mechanism lifts and lowers the end effector to perform work. When the first arm and the second arm are rotationally operated to determine the planar view position of the end effector, the clutch mechanisms of the first arm actuator and the second arm actuator are brought into the connected state.
For example, in the case of an operation of inserting an article gripped by the end effector into a hole of a work provided at a fixed position, each clutch mechanism of the first arm actuator and the second arm actuator when raising and lowering the end effector by the lifting mechanism. Is turned off to prevent the reverse input torque from being transmitted to the rotary drive of the actuator. This allows the first arm and the second arm to move freely. For this reason, even if the central axis of the article and the planar view position of the central axis of the hole are slightly deviated for some reason, the deviation is caused by the movement of the first arm and the second arm according to the force received from the inner wall of the hole. Can be absorbed to insert the article into the hole of the work.

A work transfer device may be provided below the end effector operating mechanism to move a work to be a work target of the end effector along a horizontal surface in a predetermined direction.
Since the work can be efficiently transported to the work position when the work transfer device is provided, work efficiency is improved. As described above, even if the position of the work is slightly deviated from the work position, the work can be carried out by absorbing the deviation, so that a relatively inexpensive apparatus which does not require much conveyance accuracy as a work conveyance apparatus, for example, Belt conveyor devices can be used.

  A second method of operating an articulated robot according to the present invention is the method of operating the articulated robot in a case where an article gripped by an end effector is inserted into an upward hole of a work carried by the work carrying device. Specifically, after the first arm and the second arm are actuated to position the central axis of the article so as to coincide with the central axis of the hole of the workpiece, the actuator for the first arm and the first arm With the clutch mechanisms of the two-arm actuator disconnected, the elevating mechanism is operated to insert the article into the hole of the work.

  According to the operation method of the articulated robot, the lift mechanism moves the end effector downward, and when inserting an article gripped by the end effector into the hole of the work, the clutch mechanism is disengaged to set the first arm and Allow the second arm to move freely. Thereby, even if the central axis of the article and the direction of the central axis of the hole are slightly deviated, the first arm and the second arm move according to the force received from the inner wall of the hole to absorb the deviation. , The article can be inserted into the hole of the work.

  The articulated robot according to the present invention comprises a first arm provided on a support and rotatable about an axis in the vertical direction, an actuator for a first arm for rotating the first arm, and a tip of the first arm. And an actuator for the second arm that rotates the second arm, and an end effector provided at the tip of the second arm about the vertical axis. And an actuator for an end effector operating mechanism for operating the end effector operating mechanism, and an actuator for the first arm, for the second arm An actuator and at least one actuator of the end effector operating mechanism actuator; In order to provide the clutch mechanism capable of interrupting the transmission of the reverse input torque applied to the output side to the rotary drive, the contact between the article gripped by the end effector and the work provided at the fixed position The work to be performed can be performed accurately without being affected by the positional deviation between the article and the work.

  A first operating method of an articulated robot according to the present invention is the operating method of the articulated robot in the case where an article gripped by an end effector is inserted into a hole of a work provided at a fixed position, The arm, the second arm, and the end effector operating mechanism are operated so that the central axis of the article coincides with the central axis of the hole of the work, and the tip of the article is positioned near the entrance of the hole of the work The workpiece is positioned by operating the one-axis linear motion mechanism and inserting the article into the hole of the work while the clutch mechanism of the actuator for the end effector actuation mechanism is shut off. The work to be inserted into the hole of can be performed without being affected by the positional deviation between the article and the work.

  A second method of operating an articulated robot according to the present invention is the method of operating the articulated robot in a case where an article gripped by an end effector is inserted into an upward hole of a work carried by the work carrying device. After the first arm and the second arm are actuated to position the central axis of the article so as to coincide with the central axis of the hole of the work, the actuator for the first arm and the actuator for the second arm Operation of inserting the article into the hole of the work by operating the elevating mechanism and inserting the article into the hole of the work in a state where the respective clutch mechanisms of It can be done without receiving

It is a schematic block diagram of the articulated robot concerning a 1st embodiment of this invention. It is a top view of the same articulated robot. It is a front view which abbreviate | omits and shows a part of parallel link mechanism of the articulated robot, and the actuator for attitude | position control. It is a front view which shows one state of the parallel link mechanism. It is a front view which shows the different state of the same parallel link mechanism. It is VI-PA-VI sectional drawing of FIG. It is the figure which expressed one link mechanism of the parallel link mechanism with a straight line. (A) is a figure which shows the principal part of the actuator for attitude | position control of the multi-joint robot in a cross section, (B) is the elements on larger scale, (C) is the elements on larger scale of a different state. It is IX-IX sectional drawing of FIG. It is sectional drawing of the 1 axis linear motion mechanism of the multi-joint robot. It is XI-XI sectional drawing of FIG. It is a right view of the same 1 axis linear-motion mechanism. (A) A schematic configuration view showing a use state of the multi-joint robot, (B) is a partial view showing a different state of the multi-joint robot. It is a schematic block diagram of the modification of the articulated robot concerning 1st Embodiment of this invention. It is a schematic block diagram of the different modification of the articulated robot concerning 1st Embodiment of this invention. It is a front view which abbreviate | omits and shows a part of parallel link mechanism of the articulated robot, and the actuator for attitude | position control. (A) is XVII-PA-XVII sectional drawing of FIG. 16, (B) is the elements on larger scale. (A) is a plan view of an articulated robot according to a second embodiment of the present invention, and (B) is a front view thereof. (A) is a top view which shows the different state of the multi-joint robot, (B) is the front view. (A) is a plan view showing a further different state of the articulated robot, and (B) is a front view thereof. It is a figure which shows schematic structure of the proposed articulated robot.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First Embodiment
FIG. 1 is a view showing a schematic configuration of an articulated robot according to a first embodiment, and FIG. 2 is a plan view thereof. The articulated robot 1 includes a first arm 3 provided on a support 2 fixed to a ceiling surface and supported rotatably about an axis C1 in the vertical direction, and an axis in the vertical direction at the tip of the first arm 3 A second arm 4 rotatably supported about a center C 2, a parallel link mechanism 5 rotatably supported about an axis C 3 in the vertical direction at the tip of the second arm 4, and the parallel link mechanism 5 And a single-axis linear motion mechanism 6 mounted. The parallel link mechanism 5 is one form of a rotational two degree of freedom mechanism. The parallel link mechanism 5 and the one-axis linear motion mechanism 6 constitute an end effector operation mechanism 7.

  The first arm 3 is rotated about the axis C 1 by a first arm actuator 11 installed inside the support 2. The second arm 4 is rotated about an axis C2 by a second arm actuator 12 installed on the top end of the first arm 3. The first arm actuator 11 and the second arm actuator 12 are rotary actuators with a reduction gear.

  The parallel link mechanism 5 is rotated about the axis C3 by the parallel link mechanism rotating actuator 13 and operated by the attitude control actuator 31. The parallel link mechanism rotation actuator 13 and the attitude control actuator 31 correspond to the "end effector operation mechanism actuator" in the claims, and both transmit the reverse input torque applied on the output side to the rotation drive unit. And a clutch mechanism capable of interrupting the

<Parallel link mechanism>
FIG. 3 is a front view showing the parallel link mechanism 5 and the attitude control actuator 31. As shown in FIG. A link actuation device 30 is configured by the parallel link mechanism 5 and the attitude control actuator 31. Moreover, FIG. 4 and FIG. 5 is a figure which took out and represented only the parallel link mechanism 5, and has shown the mutually different state. In addition, in FIGS. 3-5, the installation state shown in FIG. 1 is shown upside down.

  The parallel link mechanism 5 is formed by connecting the distal end side link hub 33 to the proximal end side link hub 32 via the three sets of link mechanisms 34 so as to be changeable in posture. The link hub 32 on the proximal side corresponds to a "proximal member" in the claims, and the link hub 33 on the distal side corresponds to a "distal member". In FIG. 3, only one set of link mechanism 34 is shown. The number of link mechanisms 34 may be four or more.

  Each link mechanism 34 is composed of a proximal end link member 35, a distal end link member 36, and a central link member 37, and forms a four-bar linkage linkage consisting of four rotational couples. The proximal and distal end link members 35 and 36 are L-shaped, and one end thereof is rotatably connected to the proximal link hub 32 and the distal link hub 33, respectively. The central link member 37 is rotatably connected at its both ends to the other end of the end link members 35 and 36 on the proximal end side and the distal end side.

  The parallel link mechanism 5 is a structure in which two spherical link mechanisms are combined, and each rotation pair of the link hubs 32, 33 and the end link members 35, 36, and the end link members 35, 36, and the central link member 37. The central axes of each rotation pair intersect at the respective spherical link centers PA, PB (FIG. 3) on the proximal side and the distal side. Further, on the base end side and the tip end side, the rotational pairs of the link hubs 32, 33 and the end link members 35, 36 and the distances from the respective spherical link centers PA, PB are also the same. The distances from the respective rotational pairs of the central link member 36 and the central link member 37 and the respective spherical link centers PA and PB are also the same. The central axes of the rotational pairs of the end link members 35, 36 and the central link member 37 may have a crossing angle γ (FIG. 3) or may be parallel.

  6 is a cross-sectional view taken along the line VI-PA-VI of FIG. 3, in which the central axis O1 of each rotation pair of the link hub 32 on the proximal side and the end link member 35 on the proximal side and the central link The relationship between the central axis O2 of each rotation pair of the member 37 and the proximal end side link member 35 and the spherical link center PA on the proximal side is shown. That is, the point at which the central axis O1 intersects with the central axis O2 is the spherical link center PA. The shapes and positional relationships of the distal end side link hub 33 and the distal end side end link member 36 are the same as those in FIG. 6 (not shown). In the illustrated example, the central axis O1 of each rotational pair of the link hub 32 (33) and the end link member 35 (36), and each rotational pair of the end link member 35 (36) and the central link member 37 The angle α formed by the central axis O1 and the central axis O2 of each rotational pair of the end link member 35 (36) and the central link member 37 is 90 °, but the angle α is other than 90 °. May be

  The three sets of link mechanisms 34 have the same geometrical shape. The geometrically identical shape is, as shown in FIG. 7, a geometric model in which each link member 35, 36, 37 is represented by a straight line, that is, represented by each rotation pair and a straight line connecting these rotation pairs. The model is said to have a shape in which the proximal end portion and the distal end portion with respect to the central portion of the central link member 37 are symmetrical. FIG. 7 is a diagram representing a set of link mechanisms 34 by straight lines. The parallel link mechanism 5 of this embodiment is a rotationally symmetric type, and includes the proximal end link hub 32 and the proximal end link member 35, and the distal end link hub 33 and the distal end link member 36. The positional relationship is rotationally symmetrical with respect to the center line C of the central link member 37.

  In the proximal end side link hub 32, the distal end side link hub 33, and the three sets of link mechanisms 34, the free end link hub 33 is rotatable about two orthogonal axes with respect to the proximal end link hub 32 The degree mechanism is configured. In other words, the link hub 33 on the distal end side with respect to the link hub 32 on the proximal end side is a mechanism whose attitude can be freely changed in two degrees of freedom. Although this two-degree-of-freedom mechanism is compact, the movable range of the distal end link hub 33 with respect to the proximal end link hub 32 can be taken wide.

  For example, a straight line passing through the spherical link centers PA, PB and intersecting at right angles with the central axis O1 (FIG. 6) of each rotational couple of the link hubs 32, 33 and the end link members 35, 36 is the central axis of the link hubs 32, 33. In the case of QA and QB, the maximum value of the bending angle θ (FIG. 7) between the central axis QA of the proximal link hub 32 and the central axis QB of the distal link hub 33 is about ± 90 °. it can. Further, the pivot angle φ (FIG. 7) of the distal end side link hub 33 with respect to the proximal end side link hub 32 can be set in the range of 0 ° to 360 °. The bending angle θ is a vertical angle at which the central axis QB of the distal end link hub 33 is inclined with respect to the central axis QA of the proximal end link hub 32, and the pivot angle φ is the proximal end link hub It is a horizontal angle at which the central axis QB of the link hub 33 on the distal end side is inclined with respect to the central axis QA of 32.

  The posture change of the distal end side link hub 33 with respect to the proximal end side link hub 32 is a line of rotation about the intersection point O of the central axis QA of the proximal end side link hub 32 and the central axis QB of the distal end side link hub 33 It will be. 4 shows a state in which the central axis QA of the proximal link hub 32 and the central axis QB of the distal link hub 33 are on the same line, and FIG. 5 shows the central axis QA of the proximal link hub 32. On the other hand, the central axis QB of the distal end link hub 33 has a certain operating angle. Even if the attitude changes, the distance L (FIG. 7) between the spherical link centers PA and PB on the proximal end side and the distal end side does not change.

If each link mechanism 34 satisfies the following conditions, the link hub 32 on the proximal side and the end link member 35 on the proximal side, the link hub 33 on the distal side, and the end on the distal side from geometrical symmetry. The link member 36 moves in the same manner. Therefore, the parallel link mechanism 5 functions as a constant velocity universal joint in which the proximal end and the distal end have the same rotational angle and rotate at the same speed when the rotation is transmitted from the proximal end to the distal end.
Condition 1: The angles and lengths of the central axes O1 of the rotational pairs of the link hubs 32, 33 and the end link members 35, 36 in each link mechanism 34 are equal to each other.
Condition 2: The central axis O1 of the rotational pair of the link hubs 32, 33 and the end link members 35, 36 and the central axis O2 of the rotational pair of the end link members 35, 36 and the central link member 37 are on the proximal side And at the tip side, they intersect at spherical link centers PA, PB.
Condition 3: The geometrical shapes of the proximal end link member 35 and the distal end link member 36 are equal.
Condition 4: The geometrical shapes of the proximal end portion and the distal end portion of the central link member 37 are equal.
Condition 5: With respect to the plane of symmetry of the central link member 37, the angular positional relationship between the central link member 37 and the end link members 35, 36 is the same on the proximal end side and the distal end side.

  As shown in FIGS. 3 to 5, the link hub 32 on the proximal end side is composed of a proximal end member 40 and three rotary shaft connecting members 41 provided integrally with the proximal end member 40. The base end member 40 has a circular through hole 40a (FIG. 3) at the center, and three rotary shaft connecting members 41 are arranged at equal intervals in the circumferential direction around the through hole 40a. The center of the through hole 40 a is located on the central axis QA of the proximal link hub 32. A rotational shaft 42 (see FIGS. 4 and 5) whose axial center intersects with the central axis QA of the link hub 32 on the proximal side is rotatably connected to each rotational shaft connecting member 41. One end of the proximal end side end link member 35 is connected to the rotation shaft 42.

  As shown in FIG. 6, the rotary shaft 42 is rotatably supported by the rotary shaft connecting member 41 via two bearings 43. The bearing 43 is, for example, a ball bearing such as a deep groove ball bearing or an angular ball bearing. These bearings 43 are installed in the inner diameter hole 44 provided in the rotary shaft connecting member 41 in a fitted state, and fixed by a method such as press fitting, bonding, caulking or the like. The types and installation methods of the bearings provided in the other rotation pairs are the same.

  The rotary shaft 42 has one end of a proximal end side end link member 35 and a sector-shaped bevel gear 45 which is one component of the post-axial orthogonal type reduction gear 77 so as to rotate integrally with the rotary shaft 42. Are combined. Specifically, a notch 46 is formed at one end of the proximal end side end link member 35, and a rotary shaft connecting member is provided between the inner and outer rotary shaft support portions 47 and 48 which are both sides of the notch 46 41 are arranged. The bevel gear 45 is disposed in contact with the inner surface of the inner rotation shaft support 47. Then, the rotary shaft 42 is from the inside, a through hole formed in the bevel gear 45, a through hole formed in the inner rotary shaft support portion 47, an inner ring of the bearing 43, and a through hole formed in the outer rotary shaft support portion 48. The bevel gear 45, the inner and outer rotary shaft support portions 47 and 48, and the inner ring of the bearing 43 are inserted by the holes in order and the nut 50 screwed to the head portion 42a of the rotary shaft 42 and the screw portion 42b of the rotary shaft 42. Each sandwiches and bonds them together. Spacers 51 and 52 are interposed between the inner and outer rotary shaft support portions 47 and 48 and the bearing 43, and a preload is applied to the bearing 43 when the nut 50 is screwed on.

  The rotating shaft 55 is coupled to the other end of the proximal end side end link member 35. The rotating shaft 55 is rotatably coupled to one end of the central link member 37 via two bearings 53. Specifically, a notch 56 is formed at the other end of the end link member 35 on the proximal end side, and a central link member is provided between the inner and outer rotary shaft support portions 57 and 58 which are both sides of the notch 56 One end of 37 is placed. Then, the rotary shaft 55 is inserted from the outside in the order of the through hole formed in the outer rotary shaft support 58, the inner ring of the bearing 53, and the through hole formed in the inner rotary shaft support 57. The inner and outer rotary shaft support portions 57 and 58 and the inner ring of the bearing 53 are respectively sandwiched by the head 55a and the nut 60 screwed to the screw portion 55b of the rotary shaft 55, and these are coupled to each other. Spacers 61 and 62 are interposed between the inner and outer rotary shaft support portions 57 and 58 and the bearing 53, and a preload is applied to the bearing 53 when the nut 60 is screwed on.

  As shown in FIGS. 4 and 5, the link hub 33 on the distal end side is constituted by a distal end member 70 and three rotary shaft connecting members 71 provided equidistantly on the inner surface of the distal end member 70. Be done. The center of the circumference on which each rotary shaft connecting member 71 is disposed is located on the central axis QB of the link hub 33 on the tip side. To each of the rotary shaft connecting members 71, a rotary shaft 73 whose shaft center intersects with the central axis QB of the link hub 33 at the tip end side is rotatably connected. One end of an end link member 36 on the tip end side is connected to the rotation shaft 73 of the link hub 33 on the tip end side. A rotating shaft 75 rotatably connected to the other end of the central link member 37 is connected to the other end of the end link member 36 on the distal end side. The rotary shaft 73 of the link hub 33 on the tip end side and the rotary shaft 75 of the central link member 37 are, similarly to the rotary shafts 42 and 55, respectively, a rotary shaft connecting member 71 and two bearings (not shown). The other end of the central link member 37 is rotatably connected.

As shown in FIG. 3, an attitude control actuator 31 for operating the parallel link mechanism 5 is installed on the base end member 40. The output shaft 31 a of the attitude control actuator 31 is parallel to the central axis QA of the link hub 32 on the proximal end side. The number of attitude control actuators 31 is three, the same as the number of link mechanisms 34.
In this example, the attitude control actuators 31 of the same number as the link mechanism 34 are provided, but if at least two of the three link mechanisms 34 are provided with the attitude control actuators 31, the base end The attitude of the distal end side link hub 33 with respect to the side link hub 32 can be determined.

  The bevel gear 76 attached to the output shaft 31a of the attitude control actuator 31 and the sector bevel gear 45 attached to the rotation shaft 42 of the link hub 32 on the proximal end mesh with each other. The pair of bevel gears 76 and 45 constitute an axial orthogonal speed reducer 77 in which the input side shaft and the output side shaft are orthogonal to each other. As shown in FIG. 6, the attitude control actuator 31 and the shaft orthogonal type speed reducer 77 are disposed on the inner diameter side relative to the rotation pair of the link hub 32 on the base end side and the end link member 35 on the base end side. ing.

  The parallel link mechanism 5 is operated by rotationally driving each attitude control actuator 31. Specifically, when the attitude control actuator 31 is rotationally driven, the rotation is transmitted to the rotation shaft 42 via the orthogonal orthogonal speed reducer 77 composed of a pair of bevel gears 76 and 45, and the link hub 32 on the proximal end side is The angle of the proximal end side link member 35 is changed. Thus, the attitude of the distal end link hub 33 with respect to the proximal end link hub 32 is determined. Here, the axially orthogonal reducer 77 is composed of a pair of bevel gears 76 and 45. In addition, a mechanism using a worm gear and a pinion gear, a mechanism using a hypoid gear (trade name), or the like may be used.

<Actuator for end effector operation mechanism>
The actuator for the end effector operation mechanism used as the parallel link mechanism rotation actuator 13 and the attitude control actuator 31 will be described in detail with reference to FIGS. 8 and 9.
As shown in FIG. 8, the actuator for the end effector operating mechanism has a drive motor 150 which is a rotational drive unit, and a cylindrical input shaft 153 is connected to a motor shaft 151 of the drive motor 150 by a key 152. There is. The output shaft 155 is rotatably supported at the end of the input shaft 153 via a bearing 154. The output shaft 155 is composed of a disk-shaped end surface member 155a and a back surface side member 155b fixed to the back surface. The back side member 155 b of the output shaft 155 is coupled to the inner ring of the cross roller bearing 156. The cross roller bearing 156 is provided on the housing of the drive motor 150 with the outer ring fixed.

  A clutch mechanism 230 and a reduction mechanism 160 are provided in a power transmission path from the input shaft 153 to the output shaft 155.

  The clutch mechanism 230 includes a brake plate 231, an armature chair 232 axially facing the outer surface of the brake plate 231, a friction plate 233 axially facing the inner surface of the brake plate 231, and an arm chair 232 as the brake plate 231. It is a non-excitation type electromagnetic brake provided with a plurality of brake springs 234 to be pressed, and an electromagnet 235 which makes the arm chair 232 move away from the brake plate 231 against the elasticity of the brake spring 234 by energizing the coil 235a.

  The brake plate 231 is non-rotatably fitted to the outer periphery of the connecting member 164. The connecting member 164 is a member rotatably supported by the input shaft 151 via the bearing 165. The friction plate 233 and the electromagnet 235 are spaced apart from each other by a spacer 236 interposed therebetween.

  When the coil 235a of the electromagnet 235 is not energized, as shown in FIG. 8B, the brake spring 234 presses the armature chair 232 against the brake plate 231, whereby the brake plate 231 pressed by the armature chair 232 contacts the friction plate 233. It is pressed. When the coil 235a of the electromagnet 235 is energized, as shown in FIG. 8C, the electromagnet 235 attracts the arm chair 232 and moves it in the axial direction against the elasticity of the brake spring 234 to separate it from the brake plate 231.

  When the coil 235a is deenergized, the clutch mechanism 230 having the above configuration locks the brake plate 231 and the connecting member 164 connected thereto and restrains the brake plate 231 from rotating. That is, the clutch connection state is established. When the coil 235a is energized, the lock of the brake plate 231 and the connection member 164 is released to allow rotation. That is, the clutch is disengaged.

  The reduction gear mechanism 160 is formed of a wave gear mechanism utilizing a differential between an ellipse and a perfect circle. Specifically, the reduction gear mechanism 160 includes a wave generator (wave generator) 161 coupled rotatably to the input shaft 151 and a circular spline (a rigid internal gear) disposed radially outward of the wave generator 161. And a flex spline (flexible external gear) 163 in which a cylindrical portion is sandwiched between the wave generator 161 and the circular spline 162.

  As shown in FIG. 9, the wave generator 161 has an inner ring of a ball bearing 161 b fitted and fixed to the outer periphery of a cam 161 a having an elliptical radial cross section, and is coupled to a large diameter portion of the input shaft 151 so as to transmit rotation. It is done.

  The circular spline 162 is an annular part provided with teeth on the inner periphery, and is connected to the connecting member 164 as shown in FIG. As described above, since the connecting member 164 is non-rotatable with respect to the brake plate 231, the circular spline 162 is non-rotatably connected to the brake plate 231 via the connecting member 164.

  The flex spline 163 is a thin cup-shaped component formed of a metal elastic body and provided with teeth that mesh with the teeth of the inner periphery of the circular spline 162 on the outer periphery of the cylindrical portion. The flex spline 163 is fixed to the rear side member 155 b of the output shaft 153 at its lid.

The clutch mechanism 230 and the reduction mechanism 160 operate as follows.
When the coil 235a of the clutch mechanism 230 is not energized and is in the clutch connection state, that is, when the circular spline 162 of the reduction mechanism 160 is restrained from rotating, input torque is applied from the drive motor 150 to the input shaft 151 Then, the inner ring of the ball bearing 161b of the wave generator 161 rotates integrally with the input shaft 151 first. Then, the flex spline 1631 whose inner periphery of the cylindrical portion is pressed against the outer ring of the ball bearing 161 b elastically deforms and changes the meshing position with the circular spline 162. As a result, the flex spline 163 rotates by the difference in the number of teeth with the circular spline 162, and the rotation is transmitted to the output shaft 153.

  On the other hand, when the clutch is in a disconnected state in which the coil 235a of the clutch mechanism 230 is energized, that is, when the circular spline 162 of the reduction mechanism 160 is rotatably released, reverse input torque is externally applied to the output shaft 153 First, the flex spline 163 rotates integrally with the output shaft 153. Then, the circular spline 162 rotates integrally with the flex spline 163 (without changing the meshing position with the flex spline 163). At this time, the flex spline 163 and the outer ring of the ball bearing 161b of the wave generator 161 fitted on the inner periphery thereof rotate while being elastically deformed along the outer ring of the stopped ball bearing 161b, so the input shaft No rotation is transmitted to 151. Then, if the circular spline 162 is released freely, the operation of increasing the speed of the input shaft 151 is not performed for the reverse input torque, and the rotation is suppressed as compared with the case where the circular spline 162 is unrotatable. Since the torque is greatly reduced, the output shaft 153 can be easily rotated from the output side.

  Therefore, at the time of normal operation (in a state where the coil 235 a of the electromagnet 235 is not energized), the speed reduction mechanism 160 can obtain a high speed reduction rate. Also, when the reverse input torque is applied to the output shaft 153 when the coil 235a of the electromagnet 235 is energized while the drive motor 150 is stopped, a parallel link that is an end effector operation mechanism according to the magnitude of the reverse input torque. The mechanism 5 operates. That is, the parallel link mechanism 5 becomes rotatable around the axis C3 by the parallel link mechanism rotating actuator 13 being in the clutch disconnection state, and the tip side link hub is made by the posture control actuator 31 being in the clutch disconnection state. 33 can freely change its attitude.

  An input-side encoder 170 for detecting the rotational speed of the drive motor 150 is attached to the outer surface of the drive motor 150. An output encoder (absolute encoder) 171 includes an encoder disk 171 a fitted and fixed to the outer periphery of the rear side member 155 b of the output shaft 155 and a detection portion 171 b fixed to the outer surface of the outer ring of the cross roller bearing 156. Are configured.

  By providing the input encoder 170 and the output encoder 171 in this manner, the rotational direction position of the output shaft 155 can be accurately detected even after the output shaft 155 is rotated from the output side. Thereby, when the drive motor 150 is rotationally driven next time, it is possible to position the output shaft 155 with high accuracy.

  The end effector operation actuator is fixed to the external member by a bolt inserted through the through hole 158 a of the flange portion 158. In the case of the actuator 13 for parallel link mechanism rotation, the external member is the second arm 4 (FIG. 1), and the base end member 40 (FIG. 3) of the parallel link mechanism 5 is fixed to the end surface member 155a of the output shaft 155. Further, in the case of the posture control actuator 31, the external member is the base end member 40, and the bevel gear 76 (FIG. 3) is attached to the end surface member 155a of the output shaft 155. In this case, the output shaft 155 is the output shaft 31 a of the attitude control actuator 31.

<1-axis linear motion mechanism>
In FIG. 1, the one-axis linear motion mechanism 6 is attached to the link hub 33 on the tip side of the parallel link mechanism 5 such that the linear motion direction coincides with the central axis QB of the link hub 33 on the tip side. As the 1-axis linear motion mechanism 6, for example, a slide screw structure is used.

  10 to 12 show an example of a one-axis linear motion mechanism having a slide screw structure. 10 is a cross-sectional view of the one-axis linear motion mechanism, FIG. 11 is a cross-sectional view taken along line XI-XI of FIG. 10, and FIG. 12 is a right side view of the one-axis linear motion mechanism. FIG. 10 shows a cross section taken along the line X-O 4-X in FIG.

  The one-axis linear motion mechanism 6 converts the rotation of the hollow motor 101 into a linear motion, and advances and retracts the slide shaft 102 in the axial direction. The one-axis linear motion mechanism 6 includes the hollow motor 101, a nut 103, the slide shaft 102, a pair of locking members 104 and 105, and a rotation detection unit 106.

  The hollow motor 101 includes a stator 110, a coil 111, a permanent magnet 112, and a hollow shaft 113 serving as a rotor. The energization of the coil 111 is controlled by a control device (not shown).

  The stator 110 serves as a housing of the one-axis linear motion mechanism 6, and includes a stator main body 114 at an axial center and a flange forming member 115 fixed to one end face of the stator main body 114. It consists of a combination of a pair of lids 116 and 117 fixed to the stator main body 114 and the end face of the flange forming member 115, respectively. The flange forming member 115 and the lid 116 are fixed to the stator body 114 by fixing bolts 118, and the lid 117 is fixed to the stator body 114 by fixing bolts 119.

The flange forming member 115 has a flange portion 115a on the outer periphery, and the flange portion 115a is provided with a through hole 120 for attaching the one-axis linear motion mechanism 6 to another device.
Further, inner peripheral portions of the lids 116 and 117 are radial bearing portions 121 and 122 which support the slide shaft 102 rotatably and axially movably. The radial bearings 121 and 122 are made of resin.

  In the hollow motor 101, the coil 111 is disposed on the inner periphery of the stator main body 114, and the permanent magnet 112 is disposed opposite to the inner periphery of the coil 111. The permanent magnet 112 is fixed to the outer peripheral surface of the hollow shaft 113. Both ends of the hollow shaft 113 are rotatably supported by a pair of rolling bearings 123 and 124 respectively installed on the flange forming member 115 and the stator main body 114.

  The nut 103 is fixed to the inner diameter portion of the hollow shaft 113. A female screw 125 is formed on one axial end side (left side in FIG. 10) of the nut 103, and a radial bearing portion rotatably and axially movably supports the slide shaft 102 on the other axial end side (right side in FIG. 10) It is said to be 126. For example, the nut 103 is made of resin and integrated with the hollow shaft 113 made of metal by insert molding. A convex portion 103 a provided on the outer peripheral surface of the nut 103 is in a shape of biting into the inner peripheral surface of the hollow shaft 113, and the nut 103 and the hollow shaft 113 are firmly integrated.

  The resin material used for the nut 103 and the radial bearing portions 121 and 122 of the lids 116 and 117 has excellent slidability with the slide shaft 102 and is lower in hardness than the metal constituting the slide shaft 102 Is required. Examples of resin materials that satisfy such requirements include fluorine resin compositions and ultrahigh molecular weight polyethylene resin compositions.

  The fluorine-based resin composition contains a fluorine-based resin as a main component. As a fluorine-based resin, polytetrafluoroethylene resin (abbreviated as PTFE), tetrafluoroethylene-hexafluoropropylene copolymer resin (abbreviated as FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (abbreviated as PFE), Examples thereof include ethylene-tetrafluoroethylene copolymer resin, polychlorotrifluethylene resin, and ethylene-chlorofluoroethylene copolymer resin. These may be resins consisting of two or more copolymers, terpolymers, etc., each alone or at a polymerization ratio of, for example, 1:10 to 10: 1 of the fluorine-based resin monomers.

  The slide shaft 102 is an axially longer shaft than the stator 110 forming the housing, and a male screw 127 is formed between the axial ends of the outer periphery. The male screw 127 is screwed to the female screw 125 of the nut 103.

  Further, on the outer periphery of the slide shaft 102, a locking groove 128 extending in the axial direction is formed between both axial ends. That is, the male screw 127 and the locking groove 128 are formed at the same axial position, and a part of the male screw 127 in the circumferential direction is notched by the locking groove 128. In the illustrated example, the number of the locking grooves 128 is one, but it may be dispersed in the circumferential direction.

  The locking members 104 and 105 are fixed to the lids 116 and 117 by fixing bolts 130 and 130, respectively, and the tips thereof are inserted into the locking grooves 128 of the slide shaft 102. Thereby, the slide shaft 102 is prevented from rotating. The locking groove 128 and the locking members 104 and 105 constitute the locking mechanism. The locking mechanism may have other configurations. For example, the balls may roll in the locking grooves 128.

  The rotation detecting means 106 comprises a magnetic encoder 131 provided on the hollow shaft 113 and a magnetic sensor 132 provided on the stator main body 114, and the magnetic encoder 131 and the magnetic sensor 132 are opposed to each other in the axial direction. . The magnetic sensor 132 is connected to the control device.

The one-axis linear motion mechanism 6 is configured as described above, and operates as follows.
Under the control of the control device (not shown), when the coil 111 is energized, the hollow shaft 113 of the hollow motor 101 is rotated, and the nut 103 provided on the hollow shaft 113 is rotated. The slide shaft 102 screwed to the nut 103 also tries to rotate, but since the slide shaft 102 is locked by the locking members 104 and 105 engaged with the locking groove 128, it can not be rotated, and can not rotate. Advance to The rotation of the hollow shaft 113 is detected by the rotation detection means 106, and the detection signal is sent to the control device.

  Since the male screw 127 of the slide shaft 102 and the locking groove 128 are formed at the same axial position, it is possible to obtain a sufficient stroke without increasing the axial length of the slide shaft 102. . Further, since the radial bearings 121, 122 and 126 are provided on the lids 116 and 117 and the nut 103 of the stator 110, there is no need to separately provide a bearing for supporting the slide shaft 102, and The axial linear movement mechanism 6 can be configured to be compact in the axial direction.

  The slide shaft 102 can be rotatably and axially movably supported only by the radial bearing portion 126 of the nut 103. However, by providing the radial bearing portions 121 and 122 also on the stator 110, the support of the slide shaft 102 is achieved. Stabilize. By providing the additional radial bearing portions 121 and 122 in the stator 110, the support of the slide shaft 102 can be stabilized without changing the axial length of the one-axis linear motion mechanism 6.

  Since the nut 103 is made of resin, the slidability with respect to the slide shaft 102 is good. Specifically, the slidability between the internal thread 125 of the nut 103 and the external thread 127 of the slide shaft 102 is good, and the sliding between the radial bearing portion 126 of the nut 103 and the outer peripheral surface of the slide axis 102 (thread of the external thread 127) Mobility is good. Similarly, since the radial bearing portions 121 and 122 of the lids 116 and 117 are also made of resin, the slidability between the radial bearing portions 121 and 122 and the outer peripheral surface of the slide shaft 102 is also good. For this reason, it is not necessary to supply a lubricant to each said sliding part, and the whole structure of the 1 axis | shaft linear motion mechanism 6 can be simplified.

  Furthermore, two locking bodies 104 and 105 for locking the slide shaft 102 are respectively provided at both axial ends of the stator 110. As described above, by locking the slide shaft 102 with the plurality of axially spaced locking members 104 and 105, rattling does not easily occur when the rotational direction of the nut 103 is reversed, and a stable operation is performed. be able to.

  At one end of the slide shaft 102, an end effector mounting member 140 is provided. The end effector mounting member 140 has a screw hole 141 for mounting the end effector, and is fixed to the slide shaft 102 by a fixing bolt 142. Further, at the other end of the slide shaft 102, a retaining member 142 is fixed by a fixing bolt 143.

  The one-axis linear motion mechanism 6 is fixed to the tip member 70 of the parallel link mechanism 5 by a bolt inserted through the through hole 120 of the flange portion 115a. Then, an end effector according to the work content is attached to the end effector attachment member 140.

<Operation method>
Next, an operation method of the articulated robot 1 will be described by taking an example in which an article gripped by an end effector is inserted into a hole of a work provided at a fixed position. In FIGS. 13A and 13B, the end effector 300 for gripping an article is attached to the end effector attachment member 140, the cylindrical effector 301 is gripped by the end effector 300, and the article 301 is installed in an oblique posture. The work of inserting into the cylindrical hole 302 a of the work 302 is shown. The inner diameter of the hole 302 a is slightly larger than the outer diameter of the article 301.

  As the operation method of the articulated robot 1 in this case, first, as shown in FIG. 13A, the first arm 3 and the second arm 4 are rotated to determine the planar view position of the end effector 300, and the parallel link mechanism 5 is actuated to determine the attitude of the end effector 300. The attitude of the end effector 300 is determined by the rotational position around the axial center C3 and the attitude of the distal end side link hub 33. Specifically, the tip of the article 301 is positioned near the exit of the hole 302a of the work 302, and the central axis of the article 301 calculated by calculation under control of the articulated robot 1 coincides with the central axis of the actual hole 302a. Let When the attitude of the end effector 300 is determined by the parallel link mechanism 5, the actuator 13 for rotating the parallel link mechanism and the actuator 31 for attitude control are in a clutch connection state.

  When the position and the attitude of the end effector 300 are determined, the end effector 300 is moved by the one-axis linear motion mechanism 6 as shown in FIG. 13B, and the article 301 is inserted into the hole 302 a of the work 302. At this time, the parallel link mechanism rotating actuator 13 and the attitude control actuator 31 are set in the clutch disengaged state so that the reverse input torque is not transmitted to the drive motor 150 of these actuators 13 and 31. Thereby, the parallel link mechanism 5 can freely move in response to the external force. Therefore, even if the central axis D1 of the article 301 is slightly deviated from the central axis D2 of the hole 302a due to the structural problem of the single-axis linear motion mechanism 6, the parallel operation is performed according to the force received from the inner wall of the hole 302a. By moving the link mechanism 5, the displacement can be absorbed and the article 301 can be inserted into the hole 302 a of the workpiece 302.

  As described above, in the multi-joint robot 1 in which the posture of the end effector 300 is determined by the parallel link mechanism 5, the end effector 300 is advanced or retracted in one axis direction by the one-axis linear motion mechanism 6. The difficult task of inserting the gripped article 301 into the hole 302a of the work 302 provided at the fixed position can be performed only by operating the one-axis linear motion mechanism 6, and control is easy.

  In addition, a slight deviation in the feed direction by the one-axis linear motion mechanism 6 can be tolerated. For this reason, it is possible to use, as the one-axis linear motion mechanism 6, a slide screw mechanism which may be structurally deviated in the feed direction as in this embodiment. The slide screw mechanism is a relatively lightweight and simple structure, and can be manufactured at low cost.

[Modification 1 of the First Embodiment]
FIG. 14 shows an articulated robot 1 provided with a lifting and lowering mechanism 8 for lifting and lowering the first arm 3 with respect to the above embodiment. The lifting mechanism 8 fixes the support 180 to the ceiling surface, provides the linear motion actuator 181 on the support 180 so that the advancing and retracting direction is the vertical direction, and fixes the lifting member 182 to the linear motion actuator 181. is there. The first arm 3 is supported by the raising and lowering member 182 so as to be rotatable about an axial center C1 in the vertical direction. The first arm rotation actuator 11 is provided inside the lift member 182.
The elevating mechanism 8 is covered by a cover 183. The cover 183 includes a fixing portion 183 a fixed to the ceiling surface, and an elevating portion 183 b attached to the elevating member 182 and sliding vertically with respect to the fixing member 183.

  By providing the elevating mechanism 8 in this manner, the upper and lower positions of the end effector can be arbitrarily changed, so that the working application of the articulated robot 1 is expanded. Others are the same as the said embodiment.

Modified Example 2 of First Embodiment
FIG. 15 shows an articulated robot 1 in which the configuration of the link actuation device 30 is different from that of the above embodiment. Hereinafter, only portions different in configuration from the embodiment will be described, and portions having the same configuration will be denoted by the same reference numerals as in the embodiment and the description thereof will be omitted.

  FIG. 16 is a front view showing the parallel link mechanism and a part of the attitude control actuator with the part omitted. The link actuation device 30 of this embodiment also comprises the parallel link mechanism 5 and the attitude control actuator 31 as in the above embodiment. Further, in the parallel link mechanism 5, the link hub 33 on the distal end side is connected to the proximal end link hub 32 via the three link mechanisms 34 so as to be changeable in posture. The point at which the link actuation device 30 of this embodiment differs from the above embodiment is that, as described later, each attitude control actuator 31 has its output shaft 31 a as the proximal end link hub 32 and the proximal end end link That is, the rotational center 22 of the rotation pair portion of the member 35 and the axial center thereof are arranged in alignment.

  FIG. 17A is a cross-sectional view taken along line XVII-PA-XVII in FIG. 16, and FIG. 17B is a partially enlarged view thereof. The rotary shaft 22 is rotatably supported by the rotary shaft connecting members 21 of the link hub 32 on the proximal end side, and one end of the end link member 35 on the proximal side is connected to the rotary shaft 22. The rotation shaft 22 of this embodiment has a large diameter portion 22a, a small diameter portion 22b, and an external thread portion 22c, and is rotatably supported by the rotation shaft connecting member 21 via the two bearings 23 at the small diameter portion 22b. There is. The bearing 23 is, for example, a ball bearing such as a deep groove ball bearing or an angular ball bearing. These bearings 23 are installed in a fitted state in the inner diameter groove 24 provided in the rotary shaft connection portion 21 and fixed by a method such as press fitting, bonding, caulking or the like. The types and installation methods of the bearings provided in the other rotation pairs are the same.

  The rotation shaft 22 is coaxially arranged with the output shaft 31 a of the posture control actuator 31 at the large diameter portion 22 a. The arrangement structure will be described later. Further, one end of a proximal end side end link member 35 is connected to the rotation shaft 22 so as to rotate integrally with the rotation shaft 22. That is, the rotary shaft connecting member 21 is disposed in the notch 25 formed at one end of the end link member 35 on the proximal end side, and the small diameter portion 22 b of the rotary shaft 22 is set to the end link member 35 on the proximal end. The inner ring of the bearing 23 is inserted through the through holes respectively formed in the pair of inner and outer rotary shaft supporting portions 26 and 27 which are both side portions of the notch 25 at one end of the inner surface. Then, the end link member 35 on the proximal end side and the output shaft 31a of the attitude control actuator 31 are fixed by the bolt 29 via the spacer 28 fitted to the outer periphery of the large diameter portion 22a of the rotating shaft 22 A nut 80 is screwed on the male screw 22 c of the rotary shaft 22 which protrudes from the rotary shaft support 27. Spacers 81 and 82 are interposed between the inner ring of the bearing 23 and the pair of rotary shaft support portions 26 and 27, and a preload is applied to the bearing 23 when the nut 80 is screwed on.

  The attitude control actuator 31 is disposed coaxially with the rotary shaft 22 and is fixed to the upper surface of the base end member 20 of the link hub 32 on the base end side by a motor fixing member 83. The attitude control actuator 31 is also the end effector operation mechanism actuator having the configuration shown in FIG. 8 as described above.

  In FIG. 17B, the tip end surface of the output shaft 31a is a flat flange surface 84 orthogonal to the center line of the output shaft 31a. The output shaft 31 a is connected by a bolt 29 to the rotary shaft support 26 of the end link member 35 on the proximal end side via the spacer 28. The large diameter portion 22a of the rotary shaft 22 constitutes a rotation pair of the link hub 32 on the base end side and the end link member 35 on the base end side, and the large diameter portion 22a is provided on the output shaft 31a. It is fitted in the inner diameter groove 87.

Also in the case of using the link actuation device 30 of this embodiment, the same operation and effect as in the case of using the link actuation device 30 of the above embodiment can be obtained.
In addition, as the end effector operation mechanism, a rotational two degree of freedom mechanism other than the parallel link mechanism 5 may be adopted as long as the attitude of the end effector can be changed.

Second Embodiment
FIG. 18 is a plan view and a front view of the articulated robot according to the second embodiment. The articulated robot 201 includes an elevation mechanism 208 provided on a support 202 fixed to the ground, and a first arm 203 supported by the elevation mechanism 208 and rotatably supported about an axial center C1 in the vertical direction. A second arm 204 rotatably supported around a vertical axis C2 at the tip of the first arm 203, and an end effector provided at the tip of the second arm 204 and rotating around a vertical axis C3. And an end effector rotation mechanism 205 as an end effector operation mechanism. An end effector 300 for gripping an article is attached to the tip of a rotation shaft extending downward from the end effector rotation mechanism 205.

  The first arm 203 is rotated about the axis C1 by a first arm actuator 211 installed inside the support 202. The second arm 204 is rotated about the axis C2 by a second arm actuator 212 installed on the top end of the first arm 203. The actuator 211 for the first arm and the actuator 212 for the second arm have the configuration shown in FIGS. 8 and 9 similar to the actuator for the end effector operation mechanism in the first embodiment, and are added to the output side A clutch mechanism capable of interrupting the transmission of the reverse input torque to the rotational drive unit is provided.

  Below the end effector rotation mechanism 205, a work transfer device 220 for moving the work 302 in a fixed direction along the horizontal surface is provided. The work transfer device 220 is, for example, a belt conveyor device. The work transfer device 220 is provided with a work loading stand 221 at a predetermined interval, and transfers the work 302 placed on the work loading stand 221. The workpiece 302 is positioned on the workpiece platform 221 by a plurality of positioning pins 222.

<Operation method>
As shown in FIGS. 19 and 20, the method of operating the articulated robot 1 is to insert the article 301 gripped by the end effector 300 into the upward hole 302a of the workpiece 302 transported by the workpiece transport device 220. An example will be described. The article 301 is cylindrical, and the hole 302 a of the work 302 is cylindrical with an inner diameter slightly larger than the outer diameter of the article 301.

  In operation, the first arm 203 and the second arm 204 are rotationally operated to put the end effector 300 on standby above the predetermined work position. At this time, the central axis of the article 301 gripped by the end effector 300 is positioned so as to coincide with the central axis of the hole 302 a of the workpiece 302 at the predetermined work position P. When the planar view position of the end effector 300 is determined by the first arm 203 and the second arm 204, the first arm rotation actuator 211 and the second arm rotation actuator 212 are in a clutch connection state.

  Thereafter, as shown in FIG. 19, when the work 302 is transported to the work position, the transportation is stopped there. Then, after the first arm actuator 211 and the second arm actuator 212 are in the clutch disengaged state, the lifting mechanism 208 is operated to lower the end effector 300 together with the first arm 203 and the second arm 204, and the article 301 Is inserted into the hole 302 a of the work 302.

  As described above, the central axis of the article 301 is positioned so as to coincide with the central axis of the hole 302a of the work 302, but in fact, as illustrated in FIG. The positions of the article 301 and the hole 302 a of the work 302 may be shifted due to the above. However, the first arm actuator 211 and the second arm actuator 212 are in the clutch disengaged state, and the first arm 203 and the second arm 204 can freely move. Therefore, even if the central axis of the article 301 and the central axis of the hole 302a are slightly deviated, as shown in FIG. 20, the first arm 211 and the second arm 212 respond to the force received from the inner wall of the hole 302a. By moving, the displacement can be absorbed and the article 301 can be inserted into the hole 302 a of the work 302.

  As described above, even if the position of the work 302 is slightly deviated from the work position, the work can be performed by absorbing the deviation. For this reason, as the work transfer apparatus 220, a relatively inexpensive apparatus, for example, a belt conveyor apparatus, which does not require much accuracy with respect to the position of the work 302 can be used.

  As mentioned above, although the form for implementing this invention based on the Example was demonstrated, the embodiment disclosed here is an illustration and restrictive at no points. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all the modifications within the meaning and scope equivalent to the claims.

1 ... articulated robot 3 ... first arm 4 ... second arm 5 ... parallel link mechanism (rotational 2 DOF mechanism)
6 1-axis linear motion mechanism 7 end effector operation mechanism 11 first arm rotation actuator 12 second arm rotation actuator 13 parallel link mechanism rotation actuator (end effector operation mechanism actuator)
31 ... Actuator for attitude control (actuator for end effector operation mechanism)
32: Link hub 33 on the proximal side: Link hub 34 on the distal side: Link mechanism 35: End link member 36 on the proximal side: End link member 36 on the distal side: Central link member 150: Drive motor (rotational drive) Department)
203 first arm 204 second arm 208 lifting mechanism 211 first arm rotation actuator 212 second arm rotation actuator 230 clutch mechanism 300 end effector 301 article 302 work 302a hole C1, C2 , C3 ... Axis in the vertical direction

Claims (7)

A first arm provided on a support and rotatable about a vertical axis, a first arm actuator for rotating the first arm, and a tip provided at the tip of the first arm about a vertical axis A rotatable second arm, an actuator for the second arm for rotating the second arm, and an end effector provided at the tip of the second arm, either rotating or changing attitude around an axis in the vertical direction or An end effector operation mechanism capable of supporting both, and an actuator for the end effector operation mechanism operating the end effector operation mechanism;
At least one of the first arm actuator, the second arm actuator, and the end effector operation mechanism actuator can interrupt transmission of the reverse input torque applied to the output side to the rotational drive unit Articulated robot characterized by having a flexible clutch mechanism.   The articulated robot according to claim 1, wherein the end effector operation mechanism comprises: a two-degree-of-freedom mechanism for changing the attitude of the distal end member with respect to the proximal end member provided at the distal end of the second arm; A linear translation mechanism provided on the distal end side member of the rotational two degrees of freedom mechanism for advancing and retracting the end effector in one axial direction, the actuator for the end effector actuating mechanism operates the rotational two degree of freedom mechanism An articulated robot in which the clutch mechanism is provided to the end effector operation mechanism actuator. 3. The articulated robot according to claim 2, wherein the rotating two degree of freedom mechanism has three or more sets of distal end side link hubs as the distal end side members with respect to the proximal end side link hubs as the proximal end side members. At least one of the link mechanisms is connected at its one end to the proximal end link hub and the distal end link hub so as to be changeable in attitude. A parallel link mechanism comprising an end link member and a center link member rotatably coupled at its both ends to the other ends of the proximal end and distal end end link members,
The end effector operation mechanism actuator is provided to arbitrarily change the attitude of the distal end side link hub with respect to the proximal end link hub in two or more link mechanisms among the three or more sets of link mechanisms. Articulated robot. The method of operating an articulated robot according to claim 2 or 3, wherein the article gripped by the end effector is inserted into a hole of a work provided at a fixed position.
The first arm, the second arm, and the end effector operation mechanism are actuated so that the central axis of the article coincides with the central axis of the hole of the work, and the tip of the article is the entrance of the hole of the work An articulated robot in which the one-axis linear motion mechanism is operated to insert the article into the hole of the work in a state where the clutch mechanism of the actuator for the end effector operation mechanism is shut off after positioning so as to be located nearby How to operate   The articulated robot according to claim 1, further comprising: an elevating mechanism that raises and lowers at least one of the first arm, the second arm, and the end effector operation mechanism, the actuator for the first arm and the elevating mechanism. An articulated robot, wherein the clutch mechanism is provided to a second arm actuator.   6. The articulated robot according to claim 5, wherein a work transfer device is provided below the end effector operating mechanism to move a work to be worked by the end effector in a predetermined direction along a horizontal surface. The method for operating an articulated robot according to claim 6, wherein the article gripped by the end effector is inserted into an upward hole of a workpiece transported by the workpiece transport device,
After the first arm and the second arm are operated to position the central axis of the article so as to coincide with the central axis of the hole of the workpiece, the actuator for the first arm and the actuator for the second arm The operating method of the articulated robot which operates the raising and lowering mechanism and inserts the article into the hole of the work in a state where each clutch mechanism is shut off.

Images