JP2019010693A - Hand of industrial robot and industrial robot - Google Patents

Abstract

To provide a hand of an industrial robot which can change pitches of multiple forks smoothly while reducing costs of a motor serving as a driving source of fork pitch change mechanisms even if change amounts of the pitches of the multiple forks are relatively large.SOLUTION: A hand includes: fork pitch change mechanisms 26, 27 which change pitches of multiple forks in a Y direction perpendicular to a longitudinal direction and a vertical direction of the forks; and a guide mechanism 50 which guides the forks in the Y direction. The fork pitch change mechanisms 26, 27 include: motors 29, 34; screw members 30, 35 formed with a trapezoidal thread or square thread on an outer peripheral surface and connected to output shafts of the motors 29, 34; nut members 32, 37 which engage with the screw members 30, 35; and slide members 31, 36 fixed to the forks. The nut members 32, 37 are held by the slide members 31, 36 so as to move in a direction perpendicular to the Y direction.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an industrial robot hand for transporting a transport object. The present invention also relates to an industrial robot provided with this hand.

  Conventionally, an industrial robot that transports a glass substrate for a liquid crystal display is known (for example, see Patent Document 1). The industrial robot hand described in Patent Document 1 has two forks formed in a straight line, and a fork pitch change that changes the pitch of the two forks in a direction perpendicular to the longitudinal direction and the vertical direction of the fork. Mechanism. The fork pitch changing mechanism is a motor that is a drive source, a screw member that is connected to the output shaft of the motor, a nut member that is fixed to one of the two forks, and a fork that is fixed to the other fork. And a nut member.

JP 2017-19061 A

  In order to reduce the cost of a hand having a fork pitch changing mechanism, the inventor of the present application is considering adopting a relatively inexpensive DC motor as a motor that is a driving source of the fork pitch changing mechanism. However, when the drive source of the fork pitch changing mechanism is a DC motor, an external force in a direction (orthogonal direction) perpendicular to the longitudinal direction and the vertical direction of the fork is applied to the fork in a state where the DC motor is turned off. If it acts, the fork may be displaced in the orthogonal direction. Therefore, the inventor of the present application is a screw member connected to the output shaft of the motor so that the fork does not shift in the orthogonal direction even if external force in the orthogonal direction acts on the fork in a state where the power of the DC motor is turned off. We are considering the use of screw members with trapezoidal screws or square screws on the outer peripheral surface.

  On the other hand, in recent years, there is a need to transport many types of transport objects having different widths in the orthogonal direction with a common hand. In order to respond to such needs, it is necessary to increase the pitch change amount of the two forks, and in order to increase the pitch change amount of the two forks, it is necessary to increase the length of the screw member. is there. However, if the length of the screw member is increased, the straightness (linearity) of the screw member may be reduced. In addition, if the straightness of the screw member in which the trapezoidal screw or square screw is formed on the outer peripheral surface decreases, the contact resistance between the screw member and the nut member when the screw member rotates increases, and as a result, the screw member rotates. There is a possibility that the torque for causing the screw member to increase and the screw member cannot be rotated.

  That is, if the straightness of the screw member in which the trapezoidal screw or the square screw is formed on the outer peripheral surface is lowered, the screw member cannot be rotated, and the pitch of the two forks may not be changed smoothly. If a large capacity DC motor is used as the drive source of the fork pitch changing mechanism, the screw member can be rotated even if the torque for rotating the screw member increases. This increases the cost of the DC motor.

  Accordingly, an object of the present invention is to drive a fork pitch change mechanism in an industrial robot hand having a fork pitch change mechanism that changes the pitch of a plurality of forks even if the change amount of the pitch of the plurality of forks is relatively large. An object of the present invention is to provide an industrial robot hand capable of smoothly changing the pitch of a plurality of forks while reducing the cost of a motor as a source. Moreover, the subject of this invention is providing the industrial robot provided with this hand.

  In order to solve the above-described problems, an industrial robot hand according to the present invention includes a plurality of forks formed in a straight line, a longitudinal direction and a vertical direction of the fork in an industrial robot hand that conveys an object to be conveyed. A fork pitch changing mechanism for changing the pitch of a plurality of forks in an orthogonal direction orthogonal to the guide, and a guide mechanism for guiding the forks in the orthogonal direction. The fork pitch changing mechanism includes a motor as a driving source and a trapezoidal shape on the outer peripheral surface. A screw member formed with a screw or a square screw and connected to the output shaft of the motor; a nut member engaged with the screw member; and a slide member fixed to the proximal end side of the fork; The slide member is held so as to be movable in a direction orthogonal to the orthogonal direction.

  In the industrial robot hand of the present invention, trapezoidal screws or square screws are formed on the outer peripheral surface of the screw member connected to the output shaft of the motor. Therefore, in the present invention, even if a relatively inexpensive DC motor is used as the motor, the fork is prevented from shifting in the orthogonal direction when an external force in the orthogonal direction acts on the fork in a state where the power of the motor is turned off. It becomes possible.

  Moreover, in this invention, the nut member engaged with a screw member is hold | maintained at the slide member so that the movement to the direction orthogonal to an orthogonal direction is attained. That is, in the present invention, the nut member can move in a direction orthogonal to the orthogonal direction with respect to the slide member fixed to the fork guided in the orthogonal direction by the guide mechanism. Therefore, in the present invention, the length of the screw member is increased in order to increase the pitch change amount of the plurality of forks, and as a result, even when the straightness of the screw member is reduced, the screw member is rotated. It is possible to reduce the contact resistance between the screw member and the nut member. Therefore, in the present invention, even if the length of the screw member is increased and the straightness of the screw member is lowered, or even if an inexpensive motor having a small capacity is used, the screw member is rotated, so that a plurality of forks It is possible to smoothly change the pitch of. That is, according to the present invention, even if the change amount of the pitch of the forks is relatively large, the pitch of the forks can be changed smoothly while reducing the cost of the motor that is the drive source of the fork pitch change mechanism. It becomes possible.

  In the present invention, for example, the fork pitch changing mechanism includes a bolt for attaching the nut member to the slide member, and a cylindrical member having a cylindrical portion that is formed in a cylindrical shape and is inserted into the inner peripheral side of the bolt. The nut member is formed so that a round hole-like arrangement hole in which the cylindrical portion is arranged penetrates the nut member in the orthogonal direction, and the screw hole is formed in the slide member into which the tip of the bolt is screwed. The inner diameter of the hole is larger than the outer diameter of the cylindrical portion, and the thickness of the nut member in the orthogonal direction is thinner than the length of the cylindrical portion in the orthogonal direction. In this case, the nut member can be held by the slide member so that the movement in the direction orthogonal to the orthogonal direction is possible with a relatively simple configuration.

  In the present invention, the nut member has an insertion hole through which the screw member is inserted so as to pass through the nut member in the orthogonal direction, and a female screw that engages with a trapezoidal screw or a square screw in a part of the insertion hole in the orthogonal direction. Preferably it is formed. In this case, for example, the length in the orthogonal direction of the female screw portion where the female screw is formed is approximately 1.5 times the pitch of the trapezoidal screw or the square screw. If comprised in this way, it will become possible to shorten the meshing length of a screw member and a nut member. Therefore, even if the nut member is inclined with respect to the screw member, it is possible to reduce the contact resistance between the screw member and the nut member when the screw member rotates. Therefore, the capacity of the motor can be further reduced.

  In the present invention, the fork pitch changing mechanism changes the pitch of the two forks, and the screw member includes a forward screw portion in which a forward screw is formed, a reverse screw portion in which a reverse screw is formed, and a forward screw portion. A coupling that connects the reverse thread portion, and the forward thread portion engages a nut member that is held by a slide member fixed to one of the two forks, and the reverse thread portion It is preferable that the nut member held by the slide member fixed to the other fork of the two forks is engaged. If comprised in this way, since the forward thread part and reverse thread part which were formed by the separate body are connected by the coupling, compared with the case where the forward thread part and the reverse thread part are integrally formed The length of the integrally formed part of the screw member can be shortened. Therefore, it is possible to suppress a decrease in straightness of the screw member.

  The hand of the present invention can be used in an industrial robot including an arm that is pivotally connected to the distal end side and a main body that is pivotally connected to the proximal end side of the arm. In this industrial robot, even if the change amount of the pitch of the forks is relatively large, it is possible to smoothly change the pitch of the forks while reducing the cost of the motor that is the drive source of the fork pitch change mechanism. It becomes possible.

  As described above, according to the present invention, even if the change amount of the pitch of the forks is relatively large, the pitch of the forks is smoothly changed while reducing the cost of the motor that is the driving source of the fork pitch change mechanism. It becomes possible to do.

It is a top view of the industrial robot concerning an embodiment of the invention. It is a side view of the industrial robot shown in FIG. It is a top view for demonstrating the structure inside the base of the hand shown in FIG. It is a top view for demonstrating operation | movement of the fork shown in FIG. It is a top view for demonstrating the structure of the fork pitch change mechanism in the E section of FIG. It is a top view for demonstrating the structure of the fork pitch change mechanism in the F section of FIG. It is a side view for demonstrating the structure of a fork pitch change mechanism from the GG direction of FIG. (A) is the enlarged view of the H section of FIG. 5, (B) is the enlarged view of the J section of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Overall configuration of industrial robot)
FIG. 1 is a plan view of an industrial robot 1 according to an embodiment of the present invention. FIG. 2 is a side view of the industrial robot 1 shown in FIG.

  The industrial robot 1 of this embodiment (hereinafter referred to as “robot 1”) is a horizontal articulated robot for transporting a predetermined transport object 2. The conveyance target object 2 is a glass substrate for liquid crystal displays, for example. The conveyance object 2 is formed in a rectangular flat plate shape. The robot 1 of this embodiment can transport many types of transport objects 2 having different sizes.

  The robot 1 includes two hands 3 on which the object 2 to be transported is mounted, two arms 4 to which the two hands 3 are connected to the distal end side, and a main body unit that supports the two arms 4. 5 and a base 6 that supports the main body 5 movably in the horizontal direction. The main body 5 constitutes a base that supports the base end side of the arm 4 and can move up and down, a support frame 8 that supports the arm support 7 so as to move up and down, and a lower end portion of the main body 5. 6, a base 9 that can move horizontally with respect to 6, and a revolving frame 10 that is fixed to the lower end of the support frame 8 and that can rotate with respect to the base 9.

  The arm 4 is composed of two arm parts, a first arm part 12 and a second arm part 13. The base end side of the first arm portion 12 is rotatably connected to the arm support 7. That is, the base end side of the arm 4 is rotatably connected to the main body 5. The proximal end side of the second arm portion 13 is rotatably connected to the distal end side of the first arm portion 12. The hand 3 is rotatably connected to the distal end side of the second arm portion 13. That is, the hand 3 is rotatably connected to the distal end side of the arm 4. The robot 1 includes two arm drive mechanisms that extend and contract each of the two arms 4.

  The support frame 8 holds the hand 3 and the arm 4 through the arm support 7 so as to be movable up and down. The support frame 8 includes a columnar first support frame 14 that holds the arm support 7 so as to be movable up and down, and a columnar second support frame 15 that holds the first support frame 14 so as to be movable up and down. The robot 1 moves the arm support 7 up and down relative to the first support frame 14, the lift mechanism that raises and lowers the first support frame 14 relative to the second support frame 15, and the first support frame 14 up and down. And a guide mechanism for guiding the arm support 7 in the vertical direction.

  The lower end of the second support frame 15 is fixed to the revolving frame 10. As described above, the revolving frame 10 is rotatable with respect to the base 9. The robot 1 includes a turning mechanism for turning the turning frame 10 with respect to the base 9. The base 9 can be moved horizontally with respect to the base 6 as described above. The robot 1 includes a horizontal movement mechanism that horizontally moves the base 9 with respect to the base 6.

(Hand structure)
FIG. 3 is a plan view for explaining the internal structure of the base 17 of the hand 3 shown in FIG. FIG. 4 is a plan view for explaining the operation of the forks 18 and 19 shown in FIG.

  The hand 3 includes a base portion 17 that is rotatably connected to the distal end side of the second arm portion 13, and a plurality of forks 18 and 19 on which the transport object 2 is placed on the upper surface side. The hand 3 of this embodiment includes a total of four forks 18, 19 including two forks 18 and two forks 19. In addition, the hand 3 is fixed to the upper surface side of the forks 18 and 19, and a plurality of mounting members (not shown) on which the transport target object 2 is mounted, and a transport target object mounted on the mounting member. And a plurality of suction mechanisms (not shown) that vacuum-suck the lower surface of 2.

  The base portion 17 is formed in a hollow and substantially flat rectangular parallelepiped shape with a thin vertical thickness. The forks 18 and 19 are formed in a straight line. The four forks 18 and 19 protrude from the base portion 17 in the same horizontal direction. Further, the four forks 18 and 19 are arranged in parallel to each other. When the longitudinal direction of the forks 18 and 19 (X direction in FIG. 3 etc.) is “front-rear direction” and the Y direction in FIG. 3 perpendicular to the up-down direction and the front-rear direction is “left-right direction”, the two forks 18 Are arranged on the inner side in the left-right direction, and the two forks 19 are arranged on the outer side in the left-right direction. The left-right direction (Y direction) in this embodiment is an orthogonal direction orthogonal to the longitudinal direction of the forks 18 and 19 and the up-down direction.

  The forks 18 and 19 are formed of a resin containing carbon fibers. Further, the forks 18 and 19 are formed in a hollow shape and are formed in an elongated substantially rectangular parallelepiped shape. The upper and lower surfaces of the forks 18 and 19 are flat. Further, the left and right side surfaces of the forks 18 and 19 are planes orthogonal to the left-right direction. The thicknesses of the forks 18 and 19 in the vertical direction are gradually reduced from the base ends of the forks 18 and 19 toward the tip (see FIG. 2).

  The base end portions of the forks 18 and 19 are disposed inside a base portion 17 formed in a hollow shape. As shown in FIG. 3, a fork pitch changing mechanism 26 that changes the pitch of the two forks 18 in the left-right direction and a fork pitch change that changes the pitch of the two forks 19 in the left-right direction are provided inside the base portion 17. A mechanism 27 is arranged. That is, the hand 3 includes fork pitch changing mechanisms 26 and 27.

  In the fork pitch changing mechanism 26, one fork 18 and the other fork 18 of the two forks 18 are moved by the same amount in the left and right reverse directions, and the left and right pitches of the two forks 18 are changed. The Similarly, in the fork pitch changing mechanism 27, one fork 19 and the other fork 19 of the two forks 19 are moved by the same amount in the left and right reverse directions, and the left and right pitches of the two forks 19 are changed. Is changed.

  In this embodiment, when the size of the transfer object 2 to be transferred by the robot 1 is determined, the fork pitch changing mechanism 26 has two fork pitch change mechanisms 26 as necessary before the transfer operation of transferring the transfer object 2 by the robot 1. The fork pitch changing mechanism 27 changes the left-right pitch of the two forks 19 as necessary. That is, the fork pitch changing mechanisms 26 and 27 do not change the left and right pitches of the forks 18 and 19 during the transfer operation of the transfer object 2 by the robot 1. The fork pitch changing mechanisms 26 and 27 change the left and right pitches of the forks 18 and 19 according to the size of the transport object 2 transported by the robot 1, for example, as shown in FIG. The detailed configuration of the fork pitch changing mechanisms 26 and 27 will be described later.

  Further, inside the base portion 17, a detection mechanism 21 for detecting the fork 18 on the inner end side in the left-right direction in the moving range of the two forks 18, and an outer side in the left-right direction in the moving range of the two forks 19. A detection mechanism 22 for detecting the fork 19 on the end side and a detection mechanism 23 for detecting that the fork 18 and the fork 19 adjacent in the left-right direction approach each other are arranged. That is, the hand 3 includes detection mechanisms 21 to 23.

  The detection mechanism 21 includes a sensor 56 fixed to the base frame 55 of the base portion 17 and a detection plate 57 fixed to the base end portion of one of the two forks 18. The detection mechanism 22 includes a sensor 58 fixed to the base frame 55 and a detection plate 59 fixed to the base end portion of one of the two forks 19. The sensors 56 and 58 are transmissive optical sensors each having a light emitting element and a light receiving element. In the present embodiment, the origin positions of the two forks 18 are detected using the detection mechanism 21. Further, the origin positions of the two forks 19 are detected using the detection mechanism 22.

  The detection mechanism 23 is a sensor 60 fixed to the base end portion of the other fork 19 of the two forks 19 and a detection fixed to the base end portion of the other fork 18 of the two forks 18. And a plate 61. The sensor 60 is a transmissive optical sensor having a light emitting element and a light receiving element. A sensor 62 is fixed to the base frame 55. The sensor 62 is a transmissive optical sensor having a light emitting element and a light receiving element. In this embodiment, the sensor 62 and the detection plate 59 constitute a detection mechanism 24 for detecting that the fork 19 has approached the limit position on the outer side in the left-right direction in the movement range of the two forks 19.

(Configuration of fork pitch change mechanism)
FIG. 5 is a plan view for explaining the configuration of the fork pitch changing mechanisms 26 and 27 in the E part of FIG. FIG. 6 is a plan view for explaining the configuration of the fork pitch changing mechanisms 26 and 27 in the F part of FIG. FIG. 7 is a side view for explaining the configuration of the fork pitch changing mechanisms 26 and 27 from the GG direction of FIG. 8A is an enlarged view of a portion H in FIG. 5, and FIG. 8B is an enlarged view of a portion J in FIG.

  The fork pitch changing mechanism 26 includes a motor 29 as a drive source, a screw member 30 connected to the output shaft of the motor 29, and a base end side (base end portion) of one of the two forks 18. The slide member 31 is fixed to the slide member 31, the slide member 31 is fixed to the base end side (base end portion) of the other fork 18 of the two forks 18, and the slide member 31 is attached to each of the two slide members 31. And two nut members 32 engaged with the screw member 30. The fork pitch changing mechanism 26 includes an encoder 33 that detects the amount of rotation of the screw member 30.

  The fork pitch changing mechanism 27 is configured in the same manner as the fork pitch changing mechanism 26. That is, the fork pitch changing mechanism 27 includes a motor 34 configured similarly to the motor 29, a screw member 35 configured similar to the screw member 30, and a proximal end of one fork 19 of the two forks 19. Slide member 36 fixed to the side (base end portion), slide member 36 fixed to the base end side (base end portion) of the other fork 19 out of the two forks 19, and two slide members Two nut members 37 that are attached to the respective 36 and engage with the screw member 35, and an encoder 38 that detects the amount of rotation of the screw member 35 are provided.

  The motors 29 and 34 are DC motors. The screw members 30 and 35 are formed in an elongated rod shape. The screw members 30 and 35 are disposed so that the axial direction of the screw members 30 and 35 coincides with the left-right direction, and rotate with the left-right direction as the axial direction of rotation. Moreover, the screw member 30 and the screw member 35 are arrange | positioned in the state which opened the predetermined space | interval in the front-back direction. An output shaft of the motor 29 is connected to one end of the screw member 30 via a coupling 41, and an output shaft of the motor 34 is connected to one end of the screw member 35 via a coupling 41.

  The screw members 30, 35 include forward screw portions 30 a, 35 a that constitute one end side of the screw members 30, 35 and reverse screw portions 30 b, 35 b that constitute the other end side of the screw members 30, 35. The forward screw portions 30a and 35a are formed with forward screws, and the reverse screw portions 30b and 35b are formed with reverse screws. The forward screws formed on the forward screw portions 30a and 35a and the reverse screws formed on the reverse screw portions 30b and 35b are trapezoidal screws. That is, trapezoidal screws are formed on the outer peripheral surfaces of the screw members 30 and 35.

  The forward screw portion 30 a and the reverse screw portion 30 b are formed as separate bodies and are connected by a coupling 42. Similarly, the forward screw portion 35 a and the reverse screw portion 35 b are formed separately and are connected by a coupling 42. That is, the screw member 30 includes a coupling 42 that connects the forward screw portion 30a and the reverse screw portion 30b, and the screw member 35 includes a coupling 42 that connects the forward screw portion 35a and the reverse screw portion 35b. In this embodiment, the screw member 30 is constituted by the forward screw portion 30a, the reverse screw portion 30b, and the coupling 42, and the screw member 35 is constituted by the forward screw portion 35a, the reverse screw portion 35b, and the coupling 42. Both end portions of the forward screw portions 30 a and 35 a and both end portions of the reverse screw portions 30 b and 35 b are rotatably supported by bearings 43 attached to the base frame 55. In addition, the forward thread parts 30a and 35a and the reverse thread parts 30b and 35b of this embodiment are rolling screws formed by rolling.

  The slide member 31 is formed in a rectangular parallelepiped shape. Similar to the slide member 31, the slide member 36 is formed in a rectangular parallelepiped shape. As shown in FIG. 7, the slide member 36 is fixed to a flat fixing member 44. The fixing member 44 is fixed to the proximal end portion of the fork 19. Similarly, the slide member 31 is fixed to a fixing member 44 fixed to the base end portion of the fork 18. That is, the slide member 31 is fixed to the base end portion of the fork 18 via the fixing member 44, and the slide member 36 is fixed to the base end portion of the fork 19 via the fixing member 44.

  The nut member 32 is formed in a rectangular parallelepiped shape. The nut member 37 is formed in a rectangular parallelepiped shape like the nut member 32. The nut member 32 is attached to the slide member 31 by two bolts 45, and the nut member 37 is attached to the slide member 36 by two bolts 45. That is, the fork pitch changing mechanisms 26 and 27 include bolts 45 for attaching the nut members 32 and 37 to the slide members 31 and 36.

  The fork pitch changing mechanisms 26 and 27 include a cylindrical member 46 formed in a cylindrical shape with a hook. The fork pitch changing mechanisms 26 and 27 are provided with the same number of cylindrical members 46 as the bolts 45. The cylindrical member 46 is formed in a cylindrical shape, and a bolt 45 is inserted into the inner peripheral side (specifically, a shaft portion of the bolt 45 is inserted), and a cylindrical member 46a is formed from one end of the cylindrical portion 46a. It is comprised from the annular collar part 46b which spreads in a shape (refer FIG. 8).

  The slide member 31 is formed with a notch 31 a for preventing interference with the screw member 30 and a notch 31 b for preventing interference with the screw member 35. Similarly, the slide member 36 is formed with a notch 36 a for preventing interference with the screw member 30 and a notch 36 b for preventing interference with the screw member 35. Further, as shown in FIG. 8A, the slide member 31 has two screw holes 31c into which the tip ends of the bolts 45 are screwed. The screw hole 31c is formed on one side surface of the slide member 31 in the left-right direction. Similarly, as shown in FIG. 8B, the slide member 36 has two screw holes 36c into which the tip ends of the bolts 45 are screwed. The screw hole 36c is formed on one side surface of the slide member 36 in the left-right direction.

  As shown in FIG. 8A, the nut member 32 is formed with an insertion hole 32a through which the screw member 30 is inserted. The insertion hole 32a penetrates the nut member 32 in the left-right direction. Further, the insertion hole 32 a is formed at the center of the nut member 32. A female screw that engages with the trapezoidal screw of the screw member 30 is formed in a part of the insertion hole 32a in the left-right direction. That is, the female screw is not formed in the entire region of the insertion hole 32a in the left-right direction. In this embodiment, the length in the left-right direction of the female screw portion 32 b where the female screw is formed is approximately 1.5 times the pitch of the trapezoidal screw of the screw member 30.

  Similar to the nut member 32, the nut member 37 is formed with an insertion hole 37a through which the screw member 35 is inserted (see FIG. 8B). A female screw that engages with the trapezoidal screw of the screw member 35 is formed in a part of the insertion hole 37a in the left-right direction. The length in the left-right direction of the female screw portion 37 b where the female screw is formed is substantially 1.5 times the pitch of the trapezoidal screw of the screw member 35.

  The nut member 32 is formed with a round hole-shaped arrangement hole 32c in which the cylindrical portion 46a is arranged. The arrangement hole 32c penetrates the nut member 32 in the left-right direction. Moreover, the arrangement | positioning hole 32c is formed in two places of the both sides of the insertion hole 32a in the front-back direction. Similar to the nut member 32, the nut member 37 is formed with a round hole-shaped arrangement hole 37c in which the cylindrical portion 46a is arranged. The arrangement holes 37c penetrate the nut member 37 in the left-right direction and are formed at two locations on both sides of the insertion hole 37a in the front-rear direction.

  The inner diameters of the arrangement holes 32c and 37c are larger than the outer diameter of the cylindrical portion 46a, and a gap is formed between the inner peripheral surface of the arrangement holes 32c and 37c and the outer peripheral surface of the cylindrical portion 46a. . The outer diameter of the flange 46b is larger than the inner diameter of the arrangement holes 32c and 37c. The thickness of the nut members 32 and 37 (thickness in the left-right direction) is slightly smaller than the length of the cylindrical portion 46a (length in the left-right direction). A slight gap is formed between the first and second flange portions 46b and at least one of the nut members 32 and 37 and the slide members 31 and 36. The inner diameter of the cylindrical portion 46a is slightly larger than the outer diameter of the shaft portion of the bolt 45.

  The nut member 32 is attached to the slide member 31 by a bolt 45 that is inserted from one side in the left-right direction into the inner peripheral side of the cylindrical portion 46a and screwed into the screw hole 31c. As described above, a gap is formed between the inner peripheral surface of the arrangement hole 32c and the outer peripheral surface of the cylindrical portion 46a, and in the left-right direction, between the nut member 32 and the flange portion 46b or between the nut member 32 and the slide member 31. Since a slight gap is formed between the nut member 32 and the slide member 31, the nut member 32 can move in a direction perpendicular to the left-right direction. That is, the nut member 32 is held by the slide member 31 so as to be movable in a direction orthogonal to the left-right direction. The nut member 32 is slightly movable in the left-right direction with respect to the slide member 31.

  Similarly, the nut member 37 is inserted into the inner peripheral side of the cylindrical portion 46a from one side in the left-right direction and is attached to the slide member 36 by a bolt 45 screwed into the screw hole 36c. A gap is formed between the surface and the outer peripheral surface of the cylindrical portion 46a, and a slight gap is formed between the nut member 37 and the flange portion 46b and between the nut member 37 and the slide member 36 in the left-right direction. Therefore, the nut member 37 is movable in a direction orthogonal to the left-right direction with respect to the slide member 36. That is, the nut member 37 is held by the slide member 36 so as to be movable in a direction orthogonal to the left-right direction. Further, the nut member 37 is slightly movable in the left-right direction with respect to the slide member 36.

  The nut member 32 held by the slide member 31 fixed to one of the two forks 18 is engaged with the forward screw portion 30 a and held by the slide member 31 fixed to the other fork 18. The nut member 32 to be engaged is engaged with the reverse screw portion 30b. Similarly, the nut member 37 held by the slide member 36 fixed to one of the two forks 19 is engaged with the forward screw portion 35 a and the slide member fixed to the other fork 19. The nut member 37 held by 36 is engaged with the reverse screw portion 35b.

  The two forks 18 and the two forks 19 are guided in the left-right direction by two common guide rails 48. The guide rail 48 is fixed to the base frame 55 so that the longitudinal direction of the guide rail 48 matches the left-right direction. One of the two guide rails 48 is disposed on one end side of the base frame 55 in the front-rear direction, and the other guide rail 48 is disposed on the other end side of the base frame 55 in the front-rear direction. Has been.

  As shown in FIG. 7, two guide blocks 49 that are engaged with the two guide rails 48 are fixed to the fixing member 44 that is fixed to the base end portion of the fork 19. Similarly, two guide blocks 49 that engage with each of the two guide rails 48 are fixed to the fixing member 44 that is fixed to the base end portion of the fork 18. In this embodiment, a guide mechanism 50 that guides the forks 18 and 19 in the left-right direction is constituted by the two guide rails 48 and the two guide blocks 49.

  In the fork pitch changing mechanism 26, when the motor 29 rotates and the screw member 30 rotates, as described above, the one fork 18 and the other fork 18 move by the same amount in the left and right reverse directions to move the two forks. The pitch in the left-right direction of the fork 18 is changed. Similarly, in the fork pitch changing mechanism 27, when the motor 34 rotates and the screw member 35 rotates, as described above, one fork 19 and the other fork 19 move by the same amount in the left and right reverse directions. The pitch in the left-right direction of the two forks 19 is changed.

  The encoder 33 includes a detection plate 51 fixed to the other end of the screw member 30 and a sensor 52 attached to the base frame 55. Similarly, the encoder 38 includes a detection plate 53 fixed to the other end of the screw member 35 and a sensor 54 attached to the base frame 55. The sensors 52 and 54 are transmissive optical sensors each including a light emitting element and a light receiving element.

(Main effects of this form)
As described above, in this embodiment, trapezoidal screws are formed on the outer peripheral surfaces of the screw members 30 and 35. Therefore, in the present embodiment, even if the motors 29 and 34 are relatively inexpensive DC motors, the left and right direction when an external force in the left and right direction acts on the forks 18 and 19 with the motors 29 and 34 powered off. It is possible to prevent the forks 18 and 19 from being displaced.

  In this embodiment, the nut member 32 is held by the slide member 31 fixed to the fork 18 guided in the left-right direction by the guide mechanism 50 so as to be movable in the direction orthogonal to the left-right direction. Therefore, in this embodiment, the length of the screw member 30 is increased in order to increase the amount of change in the pitch of the two forks 18, and as a result, even if the straightness of the screw member 30 decreases, the screw member 30. It is possible to reduce the contact resistance between the screw member 30 and the nut member 32 when the nut rotates.

  Similarly, in this embodiment, the nut member 37 is held on the slide member 36 fixed to the fork 19 guided in the left-right direction by the guide mechanism 50 so as to be movable in the direction orthogonal to the left-right direction. Therefore, the length of the screw member 35 is increased in order to increase the amount of change in the pitch of the two forks 19, and as a result, the screw member 35 rotates even if the straight advanceability of the screw member 35 decreases. It is possible to reduce the contact resistance between the screw member 35 and the nut member 37.

  Therefore, in this embodiment, even if the length of the screw members 30 and 35 is increased and the straightness of the screw members 30 and 35 is reduced, or the inexpensive motors 29 and 34 having a small capacity are used, the screws The pitch of the forks 18 and 19 can be changed smoothly by rotating the members 30 and 35. That is, in this embodiment, even if the amount of change in the pitch of the forks 18 and 19 is relatively large, it is possible to smoothly change the pitch of the forks 18 and 19 while reducing the cost of the motors 29 and 34.

  In this embodiment, a female screw is formed in a part in the left-right direction of the insertion hole 32a of the nut member 32, and this female screw is not formed in the entire region of the insertion hole 32a in the left-right direction. Therefore, in this embodiment, the engagement length between the screw member 30 and the nut member 32 can be shortened. Therefore, in this embodiment, even if the nut member 32 is inclined with respect to the screw member 30, it is possible to reduce the contact resistance between the screw member 30 and the nut member 32 when the screw member 30 rotates. The capacity of the motor 29 can be further reduced.

  Similarly, in this embodiment, a female screw is formed in a part in the left-right direction of the insertion hole 37a of the nut member 37, and this female screw is not formed in the entire region of the insertion hole 37a in the left-right direction. The meshing length with the nut member 37 can be shortened. Therefore, in this embodiment, even if the nut member 37 is inclined with respect to the screw member 35, it is possible to reduce the contact resistance between the screw member 35 and the nut member 37 when the screw member 35 rotates. The capacity of the motor 34 can be further reduced.

  In this embodiment, the forward screw portion 30 a and the reverse screw portion 30 b formed separately are connected by a coupling 42. Therefore, in this embodiment, it is possible to shorten the length of the integrally formed portion of the screw member 30 as compared with the case where the forward screw portion 30a and the reverse screw portion 30b are integrally formed. become. Therefore, it is possible to suppress a decrease in straightness of the screw member 30. Similarly, in this embodiment, since the forward screw portion 35a and the reverse screw portion 35b formed separately are connected by the coupling 42, the length of the integrally formed portion of the screw member 35 is reduced. It becomes possible to shorten, and as a result, it becomes possible to suppress the fall of the straight advanceability of the screw member 35.

(Other embodiments)
The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited to this, and various modifications can be made without departing from the scope of the present invention.

  In the embodiment described above, square screws may be formed on the outer peripheral surfaces of the screw members 30 and 35 instead of trapezoidal screws. Even in this case, the same effect as that of the above-described embodiment can be obtained. Moreover, in the form mentioned above, the forward screw part 30a and the reverse screw 30b may be integrally formed, and the forward screw part 35a and the reverse screw 35b may be integrally formed. Furthermore, in the embodiment described above, female threads may be formed in the entire area of the insertion hole 32a in the left-right direction, or female threads may be formed in the entire area of the insertion hole 37a in the horizontal direction.

  In the form mentioned above, the cylindrical member 46 does not need to be provided with the collar part 46b. In this case, the outer diameter of the head of the bolt 45 is larger than the inner diameter of the arrangement holes 32c and 37c. Further, in the above-described embodiment, if the nut members 32 and 37 are held by the slide members 31 and 36 so as to be movable in a direction orthogonal to the left-right direction, the fork pitch changing mechanisms 26 and 27 are The cylindrical member 46 may not be provided. In this case, for example, the shaft portion of the bolt 45 is arranged in the arrangement holes 32c and 37c. The inner diameters of the arrangement holes 32c and 37c are larger than the outer diameter of the shaft portion of the bolt 45, and a gap is formed between the inner peripheral surface of the arrangement holes 32c and 37c and the outer peripheral surface of the shaft portion of the bolt 45. Has been. Moreover, the outer diameter of the head of the bolt 45 is larger than the inner diameter of the arrangement holes 32c and 37c.

  In the embodiment described above, one of the two forks 18 may be fixed in the left-right direction, and the other fork 18 may be movable in the left-right direction. In this case, the pitch of the two forks 18 is changed by moving the other fork 18 in the left-right direction. Similarly, one of the two forks 19 may be fixed in the left-right direction, and the other fork 19 may be movable in the left-right direction. In this case, the pitch of the two forks 19 is changed by moving the other fork 19 in the left-right direction.

  In the embodiment described above, the pitch of the two forks 19 in the left-right direction may be fixed. In this case, the fork pitch changing mechanism 27 becomes unnecessary. In this case, when the pitch of the two forks 18 is changed by the fork pitch changing mechanism 26, the pitch of the four forks 18 and 19 is also changed. Similarly, the pitch of the two forks 18 in the left-right direction may be fixed. In this case, the fork pitch changing mechanism 26 becomes unnecessary. In this case, when the pitch of the two forks 19 is changed by the fork pitch changing mechanism 27, the pitch of the four forks 18 and 19 is also changed.

  In the embodiment described above, the hand 3 may not include the two forks 18 or the two forks 19. That is, the number of forks provided in the hand 3 may be two. Further, the number of forks provided in the hand 3 may be three. In this case, for example, one fork arranged in the middle is fixed in the left-right direction, and the remaining two forks are moved in the left-right direction by the fork pitch changing mechanism. In this case, the pitch of the three forks is changed by one fork pitch changing mechanism. Further, the number of forks provided in the hand 3 may be five or more. In this case, all of the five or more forks may be movable in the left-right direction, or there may be a fork fixed in the left-right direction in the five or more forks.

  In the embodiment described above, the robot 1 is a horizontal articulated robot, but the robot to which the present invention is applied may be an industrial robot other than the horizontal articulated robot. For example, the robot to which the present invention is applied may be an industrial robot disclosed in Patent Document 1 described above.

1 Robot (industrial robot)
2 Transport object 3 Hand 4 Arm 5 Main body 18, 19 Fork 26, 27 Fork pitch changing mechanism 29, 34 Motor 30, 35 Screw member 30a, 35a Forward screw portion 30b, 35b Reverse screw portion 31, 36 Slide member 31c, 36c Screw hole 32, 37 Nut member 32a, 37a Insertion hole 32b, 37b Female thread portion 32c, 37c Arrangement hole 42 Coupling 45 Bolt 46 Cylindrical member 46a Cylindrical portion 50 Guide mechanism X Fork longitudinal direction Y Orthogonal direction

Claims (6)

In industrial robot hands that transport objects to be transported,
A plurality of forks formed linearly, a fork pitch changing mechanism for changing the pitch of the plurality of forks in an orthogonal direction orthogonal to the longitudinal direction and the vertical direction of the fork, and guiding the fork in the orthogonal direction A guide mechanism,
The fork pitch changing mechanism includes a motor that is a driving source, a screw member that is formed with a trapezoidal screw or a square screw on an outer peripheral surface and coupled to an output shaft of the motor, and a nut member that engages with the screw member. A slide member fixed to the base end side of the fork,
The hand, wherein the nut member is held by the slide member so as to be movable in a direction orthogonal to the orthogonal direction. The fork pitch changing mechanism includes a bolt for attaching the nut member to the slide member, and a cylindrical member having a cylindrical portion that is formed in a cylindrical shape and through which the bolt is inserted on the inner peripheral side,
In the nut member, a round hole-shaped arrangement hole in which the cylindrical portion is arranged is formed so as to penetrate the nut member in the orthogonal direction,
The slide member is formed with a screw hole into which the tip of the bolt is screwed,
The inner diameter of the arrangement hole is larger than the outer diameter of the cylindrical portion,
The hand according to claim 1, wherein a thickness of the nut member in the orthogonal direction is thinner than a length of the cylindrical portion in the orthogonal direction. In the nut member, an insertion hole through which the screw member is inserted is formed so as to penetrate the nut member in the orthogonal direction,
3. The hand according to claim 1, wherein a female screw that engages with the trapezoidal screw or the square screw is formed in a part of the insertion hole in the orthogonal direction.   4. The hand according to claim 3, wherein the length of the female screw portion where the female screw is formed is approximately 1.5 times the pitch of the trapezoidal screw or the square screw. The fork pitch changing mechanism changes the pitch of the two forks,
The screw member includes a forward screw portion in which a forward screw is formed, a reverse screw portion in which a reverse screw is formed, and a coupling that connects the forward screw portion and the reverse screw portion,
The nut member held by the slide member fixed to one of the two forks is engaged with the forward screw portion,
5. The nut member held by the slide member fixed to the other fork of the two forks is engaged with the reverse thread portion. The hand described in any one.   A hand according to any one of claims 1 to 5, an arm to which the hand is rotatably connected to a distal end side, and a main body portion to which a proximal end side of the arm is rotatably connected. A featured industrial robot.

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