JP2016215371A - Horizontal articulated robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a horizontal articulated robot in which high positioning accuracy and excellent maintainability as a robot are maintained even when wiring is internally arranged into a joint portion about which an arm rotates.SOLUTION: A horizontal articulated robot comprises: a shaft 50 with a base end portion coupled and fixed to a first hollow arm 13; driving devices (a second motor M2 and a reduction gear 26) being coupled to a leading end portion of the shaft 50 and rotationally driving the shaft 50; and a second arm 15 serving as a hollow supporting section being mounted with the driving devices and rotatably supporting the shaft 50. Further, a wiring cable CB is arranged between the first arm 13 and the second arm 15. The shaft 50 has a through-hole 59h passing through from a bottom surface of the base end portion continued to an internal space 13c of the first arm 13 to a peripheral side surface positioned inside the second arm 15. The wiring cable CB is inserted into the through-hole 59h and arranged between an inside of the first arm 13 and an inside of the second arm 15.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a horizontal articulated robot having connection wirings straddling a plurality of arms, and more particularly to arrangement of connection wirings to joint portions of the robot.

  As one of industrial robots, there is known a horizontal articulated robot (scalar robot) in which a plurality of arms are connected so as to be turnable in the horizontal direction. The scalar robot moves the tip of the robot relative to the base by turning to change each arm to an appropriate angle with respect to a support such as another arm supported via the joint. That is, a tool or the like necessary for the work on the object is attached to the tip of such a robot so that the work is moved relative to the work position on the object so that the work on the object is performed by the tool. become.

  By the way, various devices such as a drive motor, an encoder for the motor, various sensors, and a tool are installed in some of the arms of the scalar robot. In connection with the installation of these devices, electrical wiring used for power supply and signal transmission to these devices and connection wiring such as air piping are arranged through other arms up to the arm where the device is installed. Will be.

  Such a connection wiring is often arranged through a wiring duct provided outside the scalar robot until the device to which it is connected, but in recent years, it is arranged through the inside of the scalar robot. It is often the case that they are placed inside. According to this internal arrangement, the connection wiring is arranged through the space formed inside the arm. However, in the joint portion where the structure is complicated because the two arms are pivotably connected. It is not easy to secure a space for internal arrangement, and internal arrangement of the connection wiring is not easy.

  In view of this, several scalar robots have been proposed that have a structure in which connection wirings can be internally arranged at joints of a plurality of arms. For example, the scalar robot described in Patent Document 1 is provided with a speed reducer that decelerates the rotation of the motor at a position shifted outward from the rotation center of the joint, and the external gear of the speed reducer is provided on the arm to be turned. It is made to mesh with a ring-shaped internal gear provided around the center of rotation. Thereby, a through hole is provided as a passage for passing the wiring through the rotation center of the joint.

  In addition, the scalar robot described in Patent Document 2 has a pulley or speed reducer with a hole formed in the center at the center of rotation of the joint of the arm, and a guide pipe for arranging the connection wiring in the hole. It was.

  On the other hand, in the scalar robot described in Patent Document 3, two arms are connected and supported by a connecting part such as a bearing provided at the rotation center of the joint part, and wiring is arranged on the outer peripheral side of the connecting part. An arc-shaped wiring insertion hole is formed around the connecting portion of the arm in a range in which the wiring is relatively moved.

JP 2001-353684 A Japanese Utility Model Publication No. 6-57583 JP 2003-225883 A

In general, a scalar robot is required to have a wide turning range and high positioning accuracy, and also to be easily maintained.
However, in the scalar robot described in Patent Document 1, there is a high possibility that the wiring passing through the ring-shaped gears may hinder the work, especially when the gears need to be replaced. Requires a cumbersome work of removing the wiring. Further, since this gear is used in the final stage that affects the positioning accuracy, there is a high demand for maintenance frequency and level.

  The scalar robot described in Patent Document 2 also has a high possibility that the wiring passing through it will interfere with the work during maintenance of pulleys, speed reducers, and the like, especially when replacement is necessary. The complicated work of removal is required. In addition, pulleys and reducers that are enlarged because guide pipes are placed inside are subject to wear and heat generation due to an increase in mass and increase in peripheral speed. The turning speed may be limited during operation.

  In the scalar robot described in Patent Document 3, since the arc-shaped wiring insertion hole is formed around the connecting portion of one arm, it is difficult to avoid a decrease in rigidity of the connecting portion to the arm. There is also a problem that the turning range of the arm is restricted by the rigidity.

  The present invention has been made to solve the above-mentioned problems, and the purpose thereof is to provide high positioning accuracy and good maintainability as a robot, even when wiring is internally arranged at a joint part where the arm is turned. It is to provide a horizontal articulated robot in which the above is maintained.

  The horizontal articulated robot of the present invention includes a hollow arm, a shaft having a base end connected to and fixed to the arm, a drive device connected to the tip of the shaft and rotating the shaft, A horizontal articulated robot provided with a hollow support portion that rotatably supports the shaft by mounting a drive device, and a connection wiring disposed between the arm and the support portion, The shaft is formed in a cylindrical shape in which a part of the peripheral side surface is cut out toward the axis, and extends from the bottom surface of the base end portion, which is a surface connected to the inside of the arm, to below the distal end portion. Provided with a through hole having an opening on a peripheral side surface located inside the support portion, the connection wiring is inserted between the through hole and disposed between the arm and the support portion, The base end and front The opening is sandwiched between the distal end portion and a columnar portion connecting the base end portion and the distal end portion as a portion other than the opening, and the columnar portion is a part of a peripheral side surface of the shaft The base end portion and the distal end portion have an arc surface along the outer periphery centered on the axis as an outer surface, and are narrow at the center portion in the extending direction of the columnar portion, and from the center portion, The gist of the invention is that it extends along the outer periphery toward the distal end portion and the base end portion, and the inner end surface of the through hole and the inner end surface of the columnar portion are formed as a continuous surface. .

  According to such a configuration, even when connection wiring such as electric wiring and air piping for various devices installed on the distal end side of the robot is inserted into the shaft that rotates the arm, the connection wiring is connected to the shaft. Since it is pulled out from the middle of the shaft, it cannot be inserted into a driving device such as a motor or a speed reducer connected to the tip of the shaft. In other words, there is no need to place connection wiring inside the drive unit, which has a moving part and generates friction and heat, and requires extensive maintenance, so it is connected to the shaft that forms the joint part of the arm and support part. While the wiring is arranged, the maintainability of the drive device does not change or deteriorate, and the maintainability is maintained in the same manner as the robot in which the wiring is arranged outside. As a result, the connection wiring can be internally arranged in the horizontal articulated robot while maintaining maintainability.

  In addition, since the internal arrangement of the connection wiring hardly affects the drive unit, it can be easily applied to a robot having a conventional drive unit, that is, the same high positioning accuracy as in the past can be maintained very easily. Is done. Furthermore, since there is almost no influence on the drive device, the degree of freedom in the design is maintained, and the applicability to many horizontal articulated robots is high.

  In this horizontal articulated robot, the support portion rotatably supports the shaft via a bearing fixed to the support portion, and the through hole passes through the inside of the bearing. The gist is that it is formed through the shaft.

  According to such a configuration, the shaft is rotatably supported by the support portion via the bearing at the position where the through hole is provided. As a result, the arm and the support part are directly connected and supported by the cylindrical shaft, so that the rigidity in the turning direction and the vertical direction between the arm and the support part is maintained high.

In addition, a simple structure in which the rotation and rigidity between the arm and the support portion are mainly maintained by the bearing of the bearing is provided, and this also improves the maintainability.
Furthermore, since the arm and the support portion have a simple structure connected by a shaft, the structure of the portion where the arm and the support portion face each other is simplified, and the availability around the shaft is enhanced. A seal for improving the airtightness around the shaft can be easily installed.

The gist of this horizontal articulated robot is that the drive device is disposed on an extension of the axis of the shaft.
According to such a configuration, the configuration of the transmission path of the driving force from the driving device to the shaft is simplified, the efficiency of power transmission is increased, and the design is facilitated.

  The horizontal articulated robot is characterized in that the through hole has an opening in the circumferential side of the circumferential side of the shaft that has a central angle of 270 degrees or more with respect to the central axis of the shaft. And

  According to such a configuration, the connection wiring drawn out from the through hole to the support portion side has a large space on both outer side surfaces of the wiring, and when the shaft is swung, both outer side surfaces of the wiring However, the central angle at which the opening of the through hole does not come into contact with the end in the turning direction becomes large. Thereby, the turning range of the robot in which the wiring is internally arranged can be widened by such a through hole.

  In addition, if the angle at which the connection wiring does not contact the end of the opening in the swivel direction increases, the risk of applying stress or tension to the connection wiring during turning is reduced, and the mechanical reliability of the connection wiring is maintained. It also comes to be.

  This horizontal articulated robot has a side surface in which the opening of the shaft is not formed at a portion where the central angle is the largest in a cross-sectional shape of the columnar portion viewed from an extension of the shaft center of the shaft. The gist of the present invention is that the thickness of the columnar part is at least 1/5 of the shaft diameter of the shaft.

  According to such a configuration, even when the shaft has a large opening between the base end portion and the tip end portion, by sufficiently maintaining the thickness of the shaft, The transmitted rotational driving force can be transmitted to the arm via the base end portion of the shaft.

The gist of this horizontal articulated robot is that the inner peripheral surface of the through hole is formed as a continuous surface.
According to such a configuration, since the shaft is not formed with a discontinuous surface or the like having corners that cause stress concentration even when a through hole is formed, the mechanical reliability is ensured. It becomes like this.

In addition, if the through-hole is a continuous surface, the connection wiring can suppress a frictional force generated between the connection wire and the connection surface, thereby suppressing a decrease in mechanical reliability.
In this horizontal articulated robot, the arm has a connection hole that connects the inside of the arm and the through hole in a shape facing the opening of the through hole on the base end side, and the connection wiring is connected to the through hole. The gist is that it is arranged in the arm from the hole through the connecting hole.

  According to such a configuration, the connection wiring can be arranged internally from the shaft to the arm. Further, since the connection wiring passes through the shaft and the arm, the environmental performance is further enhanced. Further, in a clean environment where airtightness inside the robot is required, the internal space up to the tip of the robot can be hermetically sealed through the shaft and the arm.

  In this horizontal articulated robot, the support portion is a tip-side arm that is turned around the rotation axis of the arm by a reaction force of the driving device, and the through hole is formed on the peripheral side surface of the tip. The gist is that it is opened to the rear side in the length direction of the side arm.

  According to such a configuration, the balance of the mass balance between the front and rear arms of the distal end when the rotation axis is the center is improved slightly. Moreover, since the utility value of the rear part of the arm on the front end side is usually low, the degree of freedom of arrangement of various devices in the front part of the arm on the front end side is not restricted by routing the connection wiring to the rear part.

  In this horizontal articulated robot, the connection wiring extended from the through hole to the support portion side is held at the end by a wiring holding device, and the wiring holding device has an axis of the shaft. The gist is to rotate around the center.

  According to such a configuration, even if the connection wiring contacts the circumferential end of the opening of the through hole, the connection wiring further rotates within the movable range of the wiring holding device, so that the connection from the shaft Application of tension or stress to the wiring is reduced. As a result, the mechanical reliability of the connection wiring is improved, and the angle at which the arm can turn is increased accordingly.

The perspective view which shows the perspective structure of one Embodiment which actualized the horizontal articulated robot concerning this invention. The fragmentary sectional view which shows the cross-sectional structure of the front of the articulated robot of the embodiment. It is a perspective view which shows the perspective structure of the shaft used for the embodiment, Comprising: (a) is a figure from right front upper direction, (b) is a figure from left front upper direction. Sectional drawing which shows the cross-section in the 4-4 line | wire of FIG. 1 of the joint part of the embodiment. Sectional drawing which shows the cross-sectional structure in the 5-5 line | wire of FIG. 1 of the joint part of the embodiment. The fragmentary sectional view which shows the structure holding the connection wiring in other embodiment. Furthermore, the fragmentary sectional view which shows the structure of the joint part in other embodiment.

Hereinafter, an embodiment of a horizontal articulated robot according to the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an overall perspective structure of a horizontal articulated robot (robot), and FIG. 2 is a sectional view showing a sectional structure taken along line 2-2 of FIG.

  As shown in FIG. 1, in the robot, the base 11 and the first arm 13 are connected via a joint part, and the first arm 13 and the second arm 15 are connected via a joint part. Is configured. That is, the robot has a base 11 installed on a floor surface or the like, and a base end portion of a first arm 13 is connected and fixed to a rotary shaft device 12 rotatably provided at an upper end portion thereof. . The rotary shaft device 12 has its base end rotated forward and backward by the first motor M <b> 1 via a reduction gear (not shown) provided in the base 11, so that the rotary shaft device 12 is pivoted relative to the base 11. It rotates around the center C1. As a result, the first arm 13 rotates in the horizontal direction with respect to the base 11 around the axis C <b> 1 of the rotary shaft device 12, that is, horizontally rotates.

  The first arm 13 is formed in a substantially rectangular tube shape having high rigidity by extruding a metal material such as aluminum. As shown in FIG. 2, the first arm 13 has an internal space 13c formed continuously in the length direction of the arm (arrow F direction and arrow R direction) in the pipe, A connection hole 13a is formed for communicating the internal space 13c with the outside. In the present embodiment, the first arm 13 has a lid (illustrated) in which each opening formed on the distal end (arrow F direction) side and the proximal end (arrow R direction) side of the tube is made of a metal material or a resin material. Closed).

  In FIG. 1, the support shaft device 14 provided at the distal end portion of the first arm 13 supports the second arm 15 in a rotatable manner by disposing the upper portion thereof within the proximal end portion of the second arm 15. ing. The second arm 15 has a second motor M2 fixed to a base end portion thereof, and an output shaft of the second motor M2 is connected to a distal end of the support shaft device 14 via a speed reducer or the like. That is, as shown in FIG. 2, the second arm 15 includes a casing 20 formed in a box shape having high rigidity by casting or the like, and a cover made of a resin material or the like covering the upper and side portions of the casing 20. 21. The casing 20 has a lower shaft hole 22h whose periphery is reinforced by a reinforcing portion 22a formed on the bottom surface 22, and an upper shaft hole 23h whose periphery is reinforced by the reinforcing portion 23a is concentric with the lower shaft hole 22h. It is formed to become.

  A cylindrical motor holding cylinder 24 is fixed to the upper shaft hole 23h so as to protrude above the housing 20, and the second motor M2 is connected to the upper end of the motor holding cylinder 24 via a flange 25F. It is fixed. A reduction gear 26 is fixed to the upper part of the motor holding cylinder 24 via a flange 26F. The reducer 26 is, for example, a harmonic drive (registered trademark) or the like, and its input shaft is connected to the second motor M2, and the rotational force transmitted from the second motor M2 transmitted to the input shaft is low and It is converted to high torque and output to its output shaft. A shaft 50 constituting the support shaft device 14 is connected to the output shaft of the speed reducer 26.

  The shaft 50 is a shaft body made of a casting and having an axial length of L1. An upper protrusion 50A connected to the output shaft of the speed reducer 26 is provided at the upper portion (tip portion). A cylindrical portion 59 whose outer shape is a shaft diameter D1 as an axial diameter and a flange 50F in contact with the lower end of the cylindrical portion 59 are formed in the lower portion (base end portion). The flange 50 </ b> F has an outer diameter larger than the shaft diameter D <b> 1 and protrudes downward from the bottom surface 22 of the housing 20. Further, the shaft 50 of the present embodiment is formed with a through hole 59h penetrating the lower portion in the axial direction, and the through hole 59h is an opening 57 formed above and in front of the upper portion of the shaft 50. Are communicated with the outer surface on the arm rear end (arrow R direction) side. That is, a through hole 59h in which connection wiring such as electric wiring and air piping can be arranged is formed in the shaft 50 in an inverted L-shaped cross section.

The structure of the shaft 50 will be described with reference to FIGS.
3A and 3B are perspective views of the shaft 50, wherein FIG. 3A is a diagram showing a perspective structure when the left front is viewed from above, FIG. 3B is a diagram showing a perspective structure when the right front is viewed from above, and FIG. 2 is a cross-sectional view showing a cross-sectional structure taken along line 4-4, and FIG. 5 is a cross-sectional view showing a cross-sectional structure taken along line 5-5 in FIG.

  More specifically, the upper protrusion 50A has a plurality of screw holes 55 formed on the upper surface thereof, and is connected to the output shaft of the speed reducer 26 via bolts or the like screwed into the screw holes 55, respectively. A top surface 56 is provided below the upper protrusion 50A.

  The top surface 56 is formed in a substantially disk shape whose diameter is slightly smaller than the shaft diameter D1, and an opening having a vertical length of L2 is provided below the top surface 56 (on the side opposite to the upper projection 50A). 57 is formed in such a manner that a part of the shaft of the shaft 50 is deeply cut away from the outer periphery in the axial direction. In addition, a circular bottom circle 58 concentric with the top surface 56 is formed in the lower part of the opening 57 so as to close the opening 57 with respect to the circumferential direction. It is formed to be continuous. That is, the top surface 56 and the bottom circle portion 58 sandwich the opening 57 therebetween, and are connected by a columnar portion 50 </ b> B that is left on the shaft 50 as a portion other than the opening 57. The columnar part 50B has an outer surface 57F along the outer circumference arc of the top surface 56 and the bottom circular part 58, and when viewed from the outer surface 57F side, the upper and lower ends are widened and the central part is formed in a narrow shape. In addition, the surface on the side of the axis C2, which is the surface opposite to the outer peripheral surface, has an inner surface 57R with a predetermined thickness between it and the outer peripheral surface.

  As shown in FIG. 4, the columnar portion 50B has a central portion with a central angle with respect to the axial center C2 of the shaft 50 of approximately 90 degrees or less, and in this embodiment, an angle of 70 to 80 degrees in the narrow portion at the center in the vertical direction. It is formed to be θ1. That is, the columnar portion 50B is in a state where the periphery thereof is notched in the range (center angle θ2) other than the center angle θ1 from the axis C2. Further, in the above-described portion of the columnar portion 50B, the thickness between the outer side surface 57F and the inner side surface 57R is formed as the column thickness T3. The column thickness T3 is set to be 1/2 or less and 1/5 or more of the shaft diameter D1, and in this embodiment, the thickness is about 1/3 of the shaft diameter D1. Due to the central angle θ1 and the column thickness T3, the columnar portion 50B is maintained to have appropriate rigidity with respect to a force such as a rotational force applied thereto, and the top surface 56 is centered. When rotated about C 2, the rotation is appropriately transmitted to the cylindrical portion 59 via the bottom circle portion 58. Note that the shape of the columnar portion 50B varies depending on the mass, motion characteristics, arm material, etc. of the robot, and the appropriate shape is determined by simulations, experiments, tests, and the like regarding the robot motion performed in advance. It is done.

  That is, the columnar portion 50B is gradually widened toward the 360 ° in a manner in which the center angle θ1 spreads downward from the position where the center angle θ1 is the smallest, and between the outer side surface 57F and the inner side surface 57R. The lower end is connected to the bottom circle 58 while the thickness of the column is gradually reduced from the column thickness T3 to the thickness T2. Further, the columnar portion 50B is connected to the lower portion of the top surface 56 while the center angle θ1 is gradually widened from the position where the center angle θ1 is the smallest toward the upper side in a manner that also widens toward the 360 °. I am letting.

  As shown in FIG. 5, in the cylindrical portion 59, the through hole 59h is formed so as to penetrate the lower portion of the shaft 50 along the substantially axial center C2, and the lower end thereof is opened on the lower surface of the flange 50F. The through-hole 59h is formed to have a thicker side wall than a general tubular member so that the rigidity of the cylindrical portion 59, particularly the rigidity against a force that causes the shaft to be curved, is maintained high. For example, the thickness on the arm front end side is the thickness T2, and the thickness on the arm rear end side is the thickness T1. The value obtained by adding the thickness T1 and the thickness T2 is set to be 1/2 or less and 1/5 or more of the shaft diameter D1. In the present embodiment, the sum of the thickness T1 and the thickness T2 is about 約 of the shaft diameter D1, and the thickness on the arm tip side (thickness T2) is the thickness on the arm rear end side (thickness T2). The thickness is larger than T1). Thereby, the through hole 59h is formed in a circular shape in which the cross-sectional shape of the inner peripheral surface thereof is flattened by crushing the arm tip side.

  By the way, the shaft 50 transmits a rotational motion about the axis C2 between the upper protrusion 50A and the flange 50F, and the transmission of the rotational motion generates a complicated stress in the shaft 50 in which the opening 57 is formed. Let At this time, if a corner portion such as a step is formed in the shaft 50, particularly the columnar portion 50B where the force is concentrated in a narrow range or a continuous portion thereof, metal due to concentration of force (stress concentration) in the corner portion. It also becomes a factor that rapidly decreases the durability of the shaft 50, such as fatigue. Therefore, in this shaft 50, the surfaces constituting the opening 57 (the lower surface of the top surface 56, the columnar portion 50B, the bottom circular portion 58) and the through hole 59h do not have corner portions such as steps on the surfaces. Further, these surfaces are also formed as a smooth and continuous continuous surface having no corners.

  In the cylindrical portion 59, a bearing B2 that constitutes the support shaft device 14 is fitted and disposed so as to contact the flange 50F. Further, a thread groove (not shown) is formed on the outer periphery of the cylindrical portion 59, and after the bearing B2 is fitted and disposed in the cylindrical portion 59, the nut 51 is screwed therein, whereby the bearing B2 is flanged. It is fixed to the shaft 50 with high rigidity so as to be sandwiched between 50F and the nut 51.

  The bearing B2 is a known ball bearing, and has a cylindrical inner ring B2a and an outer ring B2b, and the inner ring B2a and the outer ring B2b are mutually connected via a ball or the like disposed therebetween. It is coupled so as to be rotatable in the circumferential direction. That is, the inner ring B2a and the outer ring B2b have the same axis, and are rotatable about the axis. On the other hand, such a bearing B2 is configured so that the axial center of the inner ring B2a and the axial center of the outer ring B2b are always concentric, and has high rigidity against a force in a direction in which the axial centers deviate. Have come to have. That is, the plane orthogonal to the axis of the inner ring B2a and the plane orthogonal to the axis of the outer ring B2b are always parallel.

  The inner ring B2a is formed so that the inner diameter in the ring is approximately the same as the shaft diameter D1. Thereby, the bearing B2 does not have rattling between the shaft 50 inserted through the inner ring B2a. In addition, the bearing B2 is held high by the reinforcing portion 22a of the lower shaft hole 22h of the casing 20 and the fixture 52 so that the outer ring B2b is not rattled with respect to the casing 20. Fixed with rigidity.

  As a result, the shaft 50 is fixed with high rigidity to the second arm 15 in directions other than the rotation direction of the bearing B2, and is rotated forward and reverse by the second motor M2 via the speed reducer 26. Thus, the second arm 15 is rotated about the axis C2.

  The front end of the first arm 13 is connected to the lower surface of the flange 50F of the shaft 50 so that the opening of the through hole 59h formed in the lower surface corresponds to the connection hole 13a of the front end of the first arm 13. It is fixed. As a result, due to the reaction force received by the second motor M2 from the shaft 50 when the second motor M2 rotates the shaft 50 forward and backward, the second arm 15 is centered on the axis C2 and the first arm 13 is centered. Rotate in the horizontal direction, that is, turn horizontally. Further, when a force in a direction other than the rotation direction of the bearing B <b> 2 is applied to the first arm 13, the second arm 15 has high rigidity against the same force.

  A vertical rotation shaft cylinder 15 </ b> A is provided at the tip of the second arm 15. The vertical rotation shaft cylinder 15A supports the vertical rotation shaft 16 so as to be rotatable and movable in the vertical direction. The vertical rotation shaft 16 is rotated forward and backward about its own axis C3 by forward and reverse rotation of the rotary motor M3 provided in the second arm 15. Further, the vertical rotation shaft 16 is moved up and down in the vertical direction by forward and reverse rotation of the lifting motor M4 provided in the second arm 15, and the lower end portion 17 is moved up and down by the vertical movement. A tool, for example, a hand for gripping a workpiece or a hand for processing a workpiece can be attached to the lower end portion 17 of the vertical rotation shaft 16. That is, the tool is raised and lowered together with the lower end portion 17. The robot transports parts and processes parts by using each tool attached to the lower end portion 17.

  That is, the second arm 15 receives a force (stress or reaction force) in the vertical direction or the like by the operation of the tool at the tip, and the force is applied to the support shaft device 14. Thus, since it has high rigidity with respect to the direction which is not a rotation direction and is connected with the 1st arm 13, the vibration to an up-and-down etc. is suppressed. As a result, operations such as component conveyance in the vertical direction and component processing by the tool at the lower end 17 are performed with a desired accuracy due to the rigidity of the support shaft device 14 that connects the first arm 13 and the second arm 15. It comes to be.

  By the way, inside the robot, a wiring cable CB having a diameter Dc that collects wirings connected to various devices installed on the second arm 15 passes from the base 11 to the first arm 13. The second arm 15 is disposed through the through hole 59 h in the shaft 50. The wiring cable CB includes a power line that supplies power to each of the motors M2 to M4 installed on the second arm 15 and a signal line that transmits signals of various devices such as each sensor installed on the wiring cable CB. Various connection wirings are provided. That is, the inner diameter of the through hole 59h, the vertical length L2 of the opening 57, and the central angle in the circumferential direction are such that at least the wiring cable CB having the diameter Dc is inserted into the through hole 59h and the opening 57 with a margin. It is also. The wiring cable CB is disposed in the second arm 15 from the opening 57 on the side surface of the shaft 50 so that the shaft portion of the driving device such as the second motor M2 or the speed reducer 26 does not need to be inserted. The front end portion is fixed to a support 60 fixed to the flange 25F of the second motor M2 via a fixture 61. Various connection wirings are extended from the front end portion of the wiring cable CB fixed to the fixing tool 61 so as to be distributed toward the corresponding devices. In FIG. 2, drawing for these various connection wirings is omitted for convenience of explanation.

  Thereby, in this embodiment, even if the wiring cable CB is disposed inside the robot, the wiring cable CB is not inserted into the driving device that transmits the driving force to the support shaft device 14. Therefore, along with the internal arrangement of the wiring cable CB in the robot, there is no need to enlarge or complicate the structure of the driving device, and it has been conventionally adopted as the second motor M2 and the speed reducer 26. It is also possible to adopt a smaller one or a smaller one. The mounting structure of the second motor M2 and the speed reducer 26 is also a simple structure such as mounting to the motor holding cylinder 24 via the flanges 25F and 26F. Therefore, there is little risk that the maintainability of a drive device that has an operating part, a rotating part, a gear, etc. and that requires maintenance to some extent will be reduced, so that the maintainability is maintained at least at the same level as before. Become.

  Further, the rigidity against the force applied in the direction other than the rotation axis direction between the first arm 13 and the second arm 15 is maintained by the flange 50F, the cylindrical portion 59, and the bearing B2. ing. From this, the columnar portion 50B of the shaft 50 only needs to have rigidity with respect to the driving force or inertial force in the rotation direction of the second arm 15. That is, as long as the shaft 50 is provided with a columnar portion 50B having a cross section having rigidity in the rotational direction between the upper portion and the lower portion, a large opening 57 is formed there. Will be able to. According to the large opening 57, the degree of freedom of the wiring cable CB arranged there is increased, and kinking and tension applied to the wiring cable CB can be suppressed. Moreover, if the opening (center angle θ2) in the circumferential direction of the opening 57 becomes wider, the angle at which the circumferential side surface (side surface of the columnar portion 50B) of the opening 57 does not contact the wiring cable CB increases. The rotation angle becomes wider.

  Incidentally, in this embodiment, in FIG. 4, the angle at which the shaft 50 can be rotated from the position where one side surface of the columnar portion 50B is in contact with the wiring cable CB to the position where the other side surface of the columnar portion 50B is in contact with the wiring cable CB is It becomes about 180 degrees due to the influence of the thickness (diameter Dc) of the cable CB. However, even after the wiring cable CB is in contact with one side surface or the other side surface of the columnar portion 50B, due to the length of play or flexibility of the internally wired wiring cable CB in the through hole 59h, Further rotation, for example, 20 to 30 degrees in each rotation direction can be performed.

  That is, the robot using such a shaft 50 maintains the rigidity of the joint portion at the joint portion, maintains the mechanical reliability of the wiring cable CB disposed inside, and moves a wide turning angle. Is possible.

As described above, according to the horizontal articulated robot of this embodiment, the following effects can be obtained.
(1) Even when the wiring cable CB for various devices installed on the tip side of the robot is inserted into the shaft 50 that rotates the second arm 15, the wiring cable CB is opened in the middle of the shaft 50. It was made to pull out from the portion 57 into the second arm 15. As a result, the wiring cable CB is prevented from being inserted into the driving device such as the second motor M2 and the speed reducer 26 connected to the tip of the shaft 50. That is, it is not necessary to arrange the wiring cable CB inside the driving device that has an operating portion and generates friction and heat generation and requires extensive maintenance. As a result, the maintainability of the drive device does not change or decrease while the wiring cable CB is disposed in the shaft 50 constituting the joint portion of the first arm 13 and the second arm 15. The maintainability is maintained in the same manner as a robot in which wiring is arranged outside. As a result, the connection wiring can be internally arranged in the horizontal articulated robot while maintaining maintainability.

  (2) Further, since the internal arrangement of the wiring cable CB hardly affects the driving device, it can be easily applied to a robot having a conventional driving device, that is, the same high positioning accuracy as in the conventional case. Very easy to maintain. Furthermore, since there is almost no influence on the drive device, the degree of freedom in the design is maintained, and the applicability to many horizontal articulated robots is high.

  (3) The shaft 50 is rotatably supported by the housing 20 of the second arm 15 via the bearing B2 at a position where the through hole 59h is provided. As a result, the first arm 13 and the second arm 15 are directly connected and supported by the cylindrical shaft 50, and the swivel between the first arm 13 and the second arm 15 is performed. The rigidity in the direction and the vertical direction is maintained high.

(4) Furthermore, the ease of maintenance is improved by adopting a simple structure in which the rotation and rigidity between the first arm 13 and the second arm 15 are mainly maintained by bearings of the bearings.
(5) The axial centers of the driving device and the shaft 50 are arranged in a straight line. This simplifies the configuration of the transmission path of the driving force from the driving device to the shaft 50, increases the efficiency of power transmission and facilitates the design.

  (6) The opening in the circumferential direction of the opening 57 is set to 270 degrees or more with respect to the central axis (axial center C2) of the shaft 50. Thereby, the wiring cable CB drawn out from the through hole 59h to the second arm 15 side has a large space on both outer side surfaces of the wiring cable CB, and when the shaft 50 is turned, the wiring cable CB The central angle at which both outer side surfaces of CB do not contact the end portion in the turning direction of the opening 57 of the through hole 59h is increased. Thereby, the turning range of the robot in which the wiring cable CB is disposed internally can be widened by such a through hole 59h. Further, if the angle at which the wiring cable CB does not contact the end of the opening 57 in the turning direction is increased, the risk of applying stress or tension to the wiring cable CB during turning is reduced, and the mechanical reliability of the wiring cable CB is reduced. Sex will be maintained.

  (7) When the center angle of the opening 57 is the largest, the thickness between the outer side surface 57F and the inner side surface 57R of the columnar part 50B is set to 1/5 or more of the shaft diameter D1 of the shaft 50. Thus, even when the shaft 50 has a large opening 57 between the base end portion and the tip end portion, the shaft 50 is transmitted to the tip end portion of the shaft 50 by sufficiently maintaining the thickness of the shaft 50. The rotational driving force can be transmitted to the first arm 13 via the base end portion of the shaft 50.

  (8) In the shaft 50, the respective surfaces constituting the lower surface of the top surface 56, the columnar part 50B, the bottom circular part 58, and the through hole 59h are formed as continuous surfaces that do not have corners such as steps. The continuous surfaces were also formed as smooth integrated continuous surfaces having no corners. As a result, the shaft 50 is not formed with a discontinuous surface or the like having corners that cause stress concentration even when the through hole 59h is formed, so that the mechanical reliability is ensured. . If the through hole 59h is a continuous surface, the wiring cable CB can suppress a frictional force generated between the wiring cable CB and the same surface, and a decrease in mechanical reliability can be suppressed.

  (9) Since the first arm 13 is hollow, the wiring cable CB can be disposed internally from the shaft 50 to the first arm 13. Further, since the wiring cable CB passes through the shaft 50 and the first arm 13, the environmental performance is further improved. Further, in a clean environment where airtightness inside the robot is required, the internal space up to the tip of the robot can be hermetically sealed through the shaft and the arm.

  (10) In the second arm 15, the wiring cable CB is drawn to the rear end side. As a result, when the axis C2 is the center, the balance of the balance of the mass before and after the second arm 15 is slightly improved. Also, since the utility value of the rear part of the second arm 15 is usually low, the degree of freedom of arrangement of various devices in the front part of the second arm 15 is not restricted by routing the wiring cable CB to the rear part.

In addition, you may change the said embodiment as follows.
In the above embodiment, the distal end portion of the wiring cable CB is fixed to the second arm 15 by the support tool 60 and the fixing tool 61. However, the present invention is not limited to this, and the distal end portion of the wiring cable may be held in a manner movable to the arm. For example, as shown in FIG. 6, a rotating tool 65 is provided around the second motor M <b> 2 so as to be rotatable around an axis C <b> 2. 65 may be connected. Thereby, even when the outer surface of the wiring cable CB comes into contact with the circumferential end of the opening due to the rotation of the shaft 50, the rotation of the shaft 50 is further swung by the rotation range of the rotating tool 65. become. That is, it is possible to increase the rotation angle of the shaft, that is, the rotation angle of the arm while suppressing high tension, kinking, and the like from being applied to the wiring cable from the circumferential end of the opening. Thereby, the mechanical reliability of the wiring cable is maintained while widening the turning angle of the arm.

  In the above embodiment, the distal end portion of the wiring cable CB is fixed to the flange 25F by the support tool 60 and the fixing tool 61. However, the present invention is not limited to this, and the wiring cable may be fixed above the opening, for example, at the end on the side opposite to the output shaft of the motor. According to this, even if the arrangement distance of the wiring cable from the opening end to the distal end becomes long and the outer side surface of the wiring cable is pulled by contacting the circumferential end of the opening by the rotation of the shaft, In addition to the conventional angle, if the angle is, for example, 5 to 6 degrees, it is possible to suppress application of high tension or kinking to the wiring cable. Furthermore, it becomes possible to give a larger amount of slack (play) than before, and this also suppresses application of high tension or kinking to the wiring cable. As a result, the mechanical reliability of the wiring cable can be suitably maintained.

  In the above embodiment, the opening 57 is opened toward the rear of the second arm 15. However, the present invention is not limited to this, and the opening may face either side of the arm. In general, the rear of the arm is less usable and suitable for wiring arrangement, but the direction of the arm can be freely changed according to the specifications of the arm, so that such a shaft to the robot Increased freedom of application.

  In the above embodiment, the first arm 13 is formed of aluminum or the like. However, the metal material is not particularly limited to aluminum, and any material that can maintain high rigidity as an arm can be used. For example, it may be stainless steel, iron, castings, or an alloy containing at least one of these metals and aluminum. Furthermore, it may be formed by a combination of a plurality of metals including them or a resin material. Thereby, the freedom degree of selection of an arm is raised.

  In the above embodiment, the first arm 13 is formed by forming a metal material as an extruded material. However, the present invention is not limited thereto, and the arm may be formed by casting, pressing, welding, drilling, or the like as long as it has high rigidity and has an internal space. This also increases the degree of freedom of arm selection.

  In the above embodiment, the column thickness T3 of the columnar portion 50B is 1/2 or less of the shaft diameter D1 and 1/5 or more. However, the present invention is not limited to this, and the columnar portion has a column thickness greater than ½ of the shaft diameter D1 as long as it can transmit a rotational motion centered on the axis between the upper protrusion and the shaft portion. Alternatively, it may be thinner than 1/5 of the shaft diameter D1. That is, this value is different depending on the motion characteristics of the robot, the arm material, and the like, and may be determined by an experiment or a test performed in advance. Thereby, the freedom degree of formation of the shaft according to operation | movement of a robot is raised.

  Similarly, the sum of the values of the thickness (thickness T2) on the arm front end side and the thickness (thickness T1) on the arm rear end side of the cylindrical portion 59 is 1/2 or less of the shaft diameter D1 and 1/5 or more. It was the thickness of. However, the present invention is not limited to this, and if the cylindrical portion can connect the two arms with high rigidity, even if the sum of the thicknesses is greater than ½ of the shaft diameter D1, 1 / of the shaft diameter D1. It may be thinner than 5. Further, the thickness T1 may be equal to or greater than the thickness T2. That is, this value also varies depending on the motion characteristics of the robot, the arm material, and the like, and may be determined by an experiment or a test performed in advance. This also increases the degree of freedom in forming the shaft according to the movement of the robot.

  In the above embodiment, the columnar portion 50B has an angle with the central angle θ1 from the axis C2 of approximately 90 degrees or less, and in this embodiment, 70 to 80 degrees. However, the present invention is not limited to this, and if the connection wiring is appropriately wired in the through hole and the shaft can be rotated by the required rotation angle, the central angle θ1 from the axis of the columnar portion is more than 90 degrees. May be larger. That is, this value also varies depending on the motion characteristics of the robot, the arm material, and the like, and may be determined by an experiment or a test performed in advance. This also increases the degree of freedom of shape when forming the shaft.

  In the above-described embodiment, the second motor M2, the speed reducer 26, and the shaft 50 are arranged in a line on the axis C2 with their axes concentric with the axis C2. However, the present invention is not limited to this, and as long as rotational motion can be transmitted to the shaft, it is not necessary that all the axes are aligned in a line. For example, the input shaft and the output shaft may be arranged so that the shafts of the motors and shafts corresponding to the respective axes of the speed reducer are not concentric, or the motors and the speed reducers are arranged in parallel with the shafts. You may make it transmit the rotational force in between by a pulley and a belt. Thereby, the freedom degree of arrangement | positioning of a motor, a reduction gear, and a shaft is raised, and the employability of such a structure of a joint part is raised.

  In the above embodiment, the bearing B2 is a ball bearing. However, the bearing B2 is not limited to this, and the bearing may be a bearing having another structure, such as a cross roller bearing, a roller bearing, or a sliding bearing. Thereby, the freedom degree of selection of a bearing comes to be raised.

  In the above embodiment, since the first arm 13 and the second arm 15 have a simple structure connected by the shaft 50, the first arm 13 and the second arm 15 face each other. The structure of the part is also simplified. From this, the availability of the periphery of the shaft between the arms is enhanced, and for example, a seal surrounding the periphery of the shaft can be installed between the opposing arms, and the airtightness around the shaft can be easily increased. It becomes like. For example, when such airtightness is ensured between each arm and between the arm and the base, the airtightness of the entire robot can be improved, so that it can be used in environments such as clean rooms where airtightness is required. The possibility of adopting robots will be improved.

  In the above embodiment, the first arm 13 is connected to the second arm 15 through the shaft 50 by the bearing B2 with high rigidity. However, the present invention is not limited to this, and the rigidity between the first arm 13 and the second arm 15 may be other configurations such as a bearing mechanism for ensuring the rigidity between the first arm 13 and the second arm 15. You may ensure by the structure etc. which are provided in the outer periphery. Thereby, the freedom degree of the structure of the joint part of a robot is raised, and the applicability of the structure which arranges connection wiring inside in this way is raised.

  In the above embodiment, the shaft 50 is provided at the joint portion of the first arm 13 and the second arm 15, but the shaft is not limited to this, and the shaft is the joint portion between the base 11 and the first arm 13. You may provide as a rotating shaft. For example, as shown in FIG. 7, a shaft 70 connected to the first motor M <b> 1 via a speed reducer (not shown) may be provided in the base 11. In this case, the shaft 70 is provided with an opening 77 and a through hole 78 similar to the opening 57 and the through hole 59h in the above embodiment, and the inner ring of the bearing B1 is fixed to the flange 70F by the nut 71, and the bearing 70 The outer ring of B <b> 1 is fixed to the upper surface 11 a of the base 11 by the fixing tool 72. Then, by connecting and fixing the base end portion of the first arm 13 to the flange 70F, the first arm 13 can be supported on the base 11 so as to be rotatable with respect to the axis C1. As a result, the wiring cable CB can be internally arranged from the inside of the base 11 to the inside of the first arm 13 through the opening 77 and the through hole 78 of the shaft 70 and the connection hole 13b of the first arm 13. become able to. As a result, such a structure is applied to the joint portion of the robot, and the internal arrangement of the connection wiring to the robot is suitably performed.

  In the above embodiment, the shaft 50 is formed by casting. However, the present invention is not limited to this, and if the shaft 50 has a rigidity necessary for rotation around the axis and is formed to have a through hole, for example, drilling, cutting, welding, etc. It may be formed by a combination of the above. This increases the degree of freedom in selecting the shaft.

  DESCRIPTION OF SYMBOLS 11 ... Base, 11a ... Upper surface, 12 ... Rotating shaft apparatus, 13 ... 1st arm, 13a, 13b ... Connection hole, 13c ... Internal space, 14 ... Support shaft apparatus, 15 ... 2nd arm, 15A ... Up and down Rotating shaft cylinder, 16: vertical rotating shaft, 17: lower end, 20: housing, 21: cover, 22: bottom surface, 22a: reinforcing portion, 22h: lower shaft hole, 23: upper surface, 23a: reinforcing portion, 23h ... Upper shaft hole, 24 ... motor holding cylinder, 25F ... flange, 26 ... reduction gear, 26F ... flange, 50 ... shaft, 50A ... upper projection, 50B ... columnar part, 50F ... flange, 51 ... nut, 52 ... fixing tool, 55 ... Screw hole, 56 ... Top surface, 57 ... Opening, 57F ... Outer side surface, 57R ... Inner side surface, 58 ... Bottom circular part, 59 ... Cylindrical part, 59h ... Through-hole, 60, 66 ... Constructing a wiring holding device Supporting device 61, constituting a wiring holding device Fixing tool, 65: rotating tool constituting the wiring holding device, 70: shaft, 70F: flange, 71 ... nut, 72: fixing tool, 77 ... opening, 78 ... through hole, B1, B2 ... bearing, C1, C2 , C3: shaft center, CB: wiring cable, M1: first motor, M2: second motor, M3: rotary motor, M4: lifting motor, B2a: inner ring, B2b: outer ring.

Claims (8)

A hollow arm,
A shaft whose base end is connected and fixed to the arm;
A driving device connected to the tip of the shaft and rotating the shaft;
A hollow support portion that mounts the drive device and rotatably supports the shaft;
A horizontal articulated robot comprising a connection wiring disposed between the arm and the support,
The shaft is formed in a cylindrical shape in which a part of the peripheral side surface is cut out toward the axis, and extends from the bottom surface of the base end portion, which is a surface connected to the inside of the arm, to below the distal end portion. Comprising a through hole having an opening on a peripheral side surface located inside the support portion;
The connection wiring is inserted between the through hole and disposed between the arm and the support portion,
In the shaft, the opening is sandwiched between the proximal end portion and the distal end portion, and has a columnar portion that connects the proximal end portion and the distal end portion as a portion other than the opening,
The columnar portion has an arc surface along an outer periphery centering on the axis of the base end portion and the distal end portion, which is a part of a peripheral side surface of the shaft, and the columnar portion extends. Narrow at the center in the direction, and extends along the outer periphery from the center toward the distal end and the base end,
The base articulated portion which is the inner peripheral surface of the through hole and the inner surface of the columnar portion are formed as a continuous surface. The support part rotatably supports the shaft via a bearing fixed to the support part,
The horizontal articulated robot according to claim 1, wherein the through hole is formed through the shaft so as to pass through the inside of the bearing. The horizontal articulated robot according to claim 1, wherein the driving device is disposed on an extension of an axis of the shaft. The said through-hole has the opening of the shape extended in the circumferential direction of the peripheral side surface of the said shaft in which the central angle with respect to the central axis of the said shaft becomes 270 degrees or more. The horizontal articulated robot described. Of the cross-sectional shape of the columnar portion as viewed from the extension of the shaft center of the shaft, the thickness of the columnar portion having a side surface where the same opening of the shaft is not formed is the portion where the central angle is the largest. The horizontal articulated robot according to claim 4, wherein the horizontal articulated robot is set to 1/5 or more of the shaft diameter of the shaft. The arm has a connection hole that connects the inside of the arm and the through hole in a form facing the opening of the through hole on the base end side,
The horizontal articulated robot according to claim 1, wherein the connection wiring is arranged in the arm from the through hole through the connection hole. The support portion is a tip-side arm that is turned around the rotation axis of the arm by a reaction force of the drive device;
The horizontal articulated robot according to any one of claims 1 to 6, wherein the through-hole is opened on a rear side in a length direction of the arm on the distal end side on the peripheral side surface. The connection wiring extended from the through hole to the support portion side is held at its end by a wiring holding device,
The horizontal articulated robot according to any one of claims 1 to 7, wherein the wiring holding device rotates about an axis of the shaft.

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