JP2018161719A - Screw fastening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rightly perform screw fastening of a workpiece regardless of a position state of the workpiece.SOLUTION: A screw fastening device includes: a screw fastening unit 103 which has a screw fastening mechanism which is constituted of a body 201 and a heat sink 202 so as to perform screw fastening of a workpiece W and a holding mechanism which holds the workpiece W; an elevating/lowering mechanism which elevates/lowers the screw fastening unit 103 in the direction of the workpiece W; and a control section which controls the device. The control section elevates the screw fastening unit 103 by the elevating/lowering mechanism and raises the workpiece W from a mounting surface in a state that the workpiece W is held by the holding mechanism, thereby matching a horizontal surface of the workpiece W with a horizontal surface of the screw fastening unit 103 and performing screw fastening by the screw fastening mechanism.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a screw fastening device for fastening a workpiece with screws.

  An apparatus for tightening a plurality of screws to be processed (workpiece) needs to perform screw tightening in a state where the screws are correctly opposed to the screw holes and the axes thereof are aligned. When the screw is tightened, if the workpiece is tilted or the screw is tilted, the axes of each other are shifted, and the screw cannot be tightened correctly. In addition, when performing screw tightening while placing and moving a workpiece on a conveyor that is automatically produced, it is necessary to perform screw tightening in accordance with the speed of the conveyor and the inclination of the conveyor surface.

  Conventionally, a traveling body that travels with the conveyor is provided above the conveyor of the automation line, a nut runner for screw tightening is provided on the traveling body, and the traveling member is brought into contact with the workpiece, thereby bringing the traveling body into the workpiece. There is a technique for positioning (see, for example, Patent Document 1 below). In addition, there is a technique in which a chucking claw can be rotated with respect to a gripping surface of an electronic component or the like and can be gripped following the surface shape of the gripping surface (see, for example, Patent Document 2 below). In addition, there is a technique in which a leaf spring is provided on a claw of a workpiece gripping member and the workpiece is pressed by the leaf spring to prevent the workpiece from falling (for example, see Patent Document 3 below).

Japanese Utility Model Publication No. 61-181622 JP-A-62-94228 JP 2000-174108 A

  However, in the related art, when there are a plurality of workpiece screws, if one of the screws is tightened strongly, a part of the workpiece may be lifted and the other screw portion may not be tightened. For example, when a work consists of a main body and a lid, and a waterproof packing is provided between the main body and the lid, the lift of the lid on the opposite side of the screw tightening point becomes prominent, and the positions of the screw holes on the main body and the lid shift. . In this case, the driver's idle rotation in which the axes are misaligned and the screw thread does not fit, the screw biting that the screw enters the screw hole diagonally and stops halfway, the screw head crushing to prevent the driver tip from entering the screw head part correctly, etc. A malfunction occurs.

  Also, when tightening screws while a workpiece is running on a conveyor in an automated line, correct screws due to unevenness on the conveyor, inclination of the conveyor with respect to the horizontal state, inclination of the workpiece on the conveyor surface due to heavy workpieces, etc. Tightening cannot be performed.

  In one aspect, an object of the present invention is to correctly perform screw tightening of a workpiece regardless of the position state of the workpiece.

  In one proposal, the screw tightening device includes: a screw tightening mechanism including a screw tightening mechanism for tightening a work including a housing and a lid; and a gripping mechanism for gripping the work. A lifting mechanism that lifts and lowers the workpiece in the direction of the workpiece, and a control unit that controls the apparatus, and the control unit lifts the screw tightening unit by the lifting mechanism in a state where the workpiece is gripped by the gripping mechanism. Then, by lifting the workpiece from the mounting surface, the horizontal plane of the workpiece is made to coincide with the horizontal plane of the screw tightening unit, and screw tightening by the screw tightening mechanism is a requirement.

  According to one embodiment, the work can be correctly screwed regardless of the position of the work.

FIG. 1 is a perspective view showing the screw tightening device of the first embodiment. FIG. 2 is an exploded perspective view showing an example of a workpiece that is screwed by the screw fastening device of the first embodiment. FIG. 3 is a block diagram illustrating functions of a control unit of the screw tightening apparatus according to the first embodiment. FIG. 4 is a block diagram illustrating a hardware configuration example of the screw tightening device according to the first embodiment. FIG. 5 is a front view showing the screw fastening device of the first embodiment. FIG. 6 is a top perspective view showing the screw tightening unit of the screw tightening device according to the first embodiment. FIG. 7 is a bottom perspective view showing the screw tightening unit of the screw tightening device according to the first embodiment. FIG. 8 is a partially enlarged perspective view of the screw tightening unit of the screw tightening device according to the first embodiment. FIG. 9 is a front view for explaining an operation procedure of the screw tightening device according to the first embodiment. (Part 1) FIG. 10 is a front view for explaining an operation procedure of the screw tightening device according to the first embodiment. (Part 2) FIG. 11 is a front view for explaining an operation procedure of the screw tightening device according to the first embodiment. (Part 3) FIG. 12 is a front view for explaining the operation procedure of the screw tightening device according to the first embodiment. (Part 4) FIG. 13 is a front view for explaining the operation procedure of the screw tightening apparatus according to the first embodiment. (Part 5) FIG. 14 is a front view for explaining the operation procedure of the screw tightening apparatus according to the first embodiment. (Part 6) FIG. 15 is a front view for explaining an operation procedure of the screw fastening device according to the first embodiment. (Part 7) FIG. 16 is a front view for explaining an operation procedure of the screw tightening device according to the first embodiment. (Part 8) FIG. 17A is a front view showing a workpiece positioning operation in a state where the carriage is tilted in the first embodiment. (Part 1) FIG. 17B is a front view showing a workpiece positioning operation in a state where the carriage is tilted in the first embodiment. (Part 2) FIG. 18A is a front view showing a workpiece positioning operation in a state where the screw fastening device is inclined in the first embodiment. (Part 1) FIG. 18B is a front view showing a workpiece positioning operation in a state where the screw fastening device is inclined in the first embodiment. (Part 2) FIG. 19 is a diagram illustrating a state when the workpiece is tightened by the screw tightening device according to the first embodiment. FIG. 20 is a front view illustrating a workpiece conveyance state of the screw tightening apparatus according to the first embodiment. FIG. 21A is a flowchart illustrating an operation procedure of the screw tightening device according to the first exemplary embodiment. (Part 1) FIG. 21B is a flowchart illustrating an operation procedure of the screw tightening device according to the first exemplary embodiment. (Part 2) FIG. 21C is a flowchart illustrating an operation procedure of the screw tightening device according to the first exemplary embodiment. (Part 3) FIG. 22 is a front view showing the screw fastening device of the second embodiment. (Part 1) FIG. 23 is a front view showing the screw tightening device of the second embodiment. (Part 2) FIG. 24A is a flowchart of an operation procedure of the screw tightening device according to the second embodiment. (Part 1) FIG. 24B is a flowchart illustrating an operation procedure of the screw tightening apparatus according to the second embodiment. (Part 2) FIG. 24C is a flowchart illustrating an operation procedure of the screw tightening apparatus according to the second embodiment. (Part 3) FIG. 25 is a front view showing the screw tightening device of the third embodiment. (Part 1) FIG. 26 is a front view showing the screw tightening device of the third embodiment. (Part 2)

(Embodiment 1)
FIG. 1 is a perspective view showing the screw tightening device of the first embodiment. The screw tightening device 100 is provided, for example, so as to straddle the conveyor 150 in a part of the conveyance direction (left-right direction in the drawing) X of the conveyor 150 of the automatic line that conveys the object (work) W to be screwed. Can do. As will be described later, the screw tightening device 100 is not limited to being applied to an automatic line, and can also perform screw tightening on the workpiece W placed on a carriage or the like and not moving.

  The screw tightening device 100 includes a screw tightening unit 103 that is suspended by a rail 102 above the support column 101. The screw tightening device 100 includes a moving mechanism, an elevating mechanism, a gripping mechanism, a screw tightening mechanism, and the like (details of which will be described later). Each of these mechanisms is controlled by a control unit described later according to a predetermined operation procedure.

  The moving mechanism moves the screw fastening unit 103 at a speed synchronized with the workpiece W placed on the conveyor 150 (placement surface) within a predetermined length X1 of the rail 102 in the transport direction X. The lifting mechanism moves the screw tightening unit 103 up and down in the direction of the workpiece W before and after supporting the workpiece W. Although the details of the lifting mechanism will be described later, a motor that suspends and lifts the screw tightening unit 103 via a wire, and a telescopic leg that is provided on the screw tightening unit 103 and lifts the workpiece W from the placing surface such as the conveyor 150. The gripping mechanism is provided in the screw fastening unit 103 and grips the workpiece W.

  For example, the control unit is provided inside the screw tightening unit 103. The control unit controls the lifting mechanism to lower the screw fastening unit 103 in the height direction Z, controls the gripping mechanism to grip the workpiece W, and then lifts the workpiece W from the placement surface by the lifting mechanism. And a control part controls a moving mechanism in the state which lifted the workpiece | work W from mounting surfaces, such as the conveyor 150, and moves the screw fastening unit 103 to the conveyance direction X synchronizing with the movement of the conveyor 150. FIG.

  Thereafter, the control unit controls the screw tightening mechanism to tighten the workpiece W while moving the screw tightening unit 103 between the lengths X1. Thereafter, the elevating mechanism is controlled to lower the screw tightening unit 103 and place the workpiece W on the conveyor 150 again. As a result, it is possible to perform screw tightening on the workpiece W while the workpiece W moves between places where the screw tightening device 100 is disposed (the length X1 of the rail 102).

  FIG. 2 is an exploded perspective view showing an example of a workpiece that is screwed by the screw fastening device of the first embodiment. The workpiece W includes a housing 201 that houses an electronic device therein, a lid (heat sink) 202 that covers an opening of the housing 201, and an annular elastic body such as rubber provided between the housing 201 and the heat sink 202. And a packing 203 made of

  The workpiece W flowing on the conveyor 150 is conveyed to the screw tightening device 100 portion with the packing 203 fitted on the housing 201 and the heat sink 202 placed thereon in the procedure preceding the screw tightening device 100. The screw tightening device 100 performs screw tightening at a plurality of locations of the workpiece W.

  A flange portion (protruding portion) 211 that protrudes outward is formed on the entire periphery of the upper portion (opening portion) of the housing 201, and the protruding portion 211 has a predetermined interval (three pieces per side in the illustrated example, a total of 12 pieces) A plurality of screw holes 212 are formed.

  The heat sink 202 is formed with a plurality of fins in order to dissipate heat generated by the electronic device inside the device, and has the same outer diameter (width and length) as the protruding portion 211 of the housing 201. A plurality of screw holes (without screw grooves) 221 are formed in the heat sink 202 at positions corresponding to the positions of the screw holes 212 of the housing 201. The screw 222 is inserted into the screw hole 221 portion of the heat sink 202 and screwed into the screw hole 212 of the housing 201, so that the opening of the housing 201 can be closed and the heat sink 202 can be fixed to the housing 201.

  At this time, by arranging the packing 203 on the entire circumference of the protruding portion 211 of the casing 201, the casing 201 and the heat sink 202 can be in close contact with each other by the packing 203, and the inside of the casing 201 is sealed. Can also be waterproof and dustproof.

  FIG. 3 is a block diagram illustrating functions of a control unit of the screw tightening apparatus according to the first embodiment. A control setting value and a control state are input to and output from the control unit 301 via the input / output unit 302, and the control state is displayed on the display unit 303.

  The control unit 301 executes the various controls described above and performs screw tightening on the workpiece W. The control unit 301 includes a robot control unit 311, a lift control unit 312, a grip control unit 313, and a screw tightening control unit 314.

  The robot control unit 311 controls the entire control unit 301. When the robot control unit 311 detects that the workpiece W is positioned in the screw tightening device 100 with a sensor or the like, the robot control unit 311 causes the control units 312 to 314 to execute a series of screw tightening procedures for the workpiece W, and Controls until screw tightening is complete.

  The elevating control unit 312 controls the elevating operation with respect to the elevating mechanism 321. The elevating mechanism 321 includes an elevating motor and a telescopic leg, which will be described later, and controls the screw tightening unit 103 to elevate. The elevation detection unit 322 detects the elevation position of the screw tightening unit 103 with a sensor or the like, and outputs it to the elevation control unit 312.

  The grip control unit 313 controls the grip operation with respect to the grip mechanism 323. The gripping mechanism 323 includes a cylinder such as an air cylinder that grips the workpiece W. As will be described later, the cylinders are provided in the left-right direction X, the front-rear direction Y, and the height direction Z that holds the work W from above, respectively. The gripping position detection unit 324 detects the gripping state by the gripping mechanism 323 with a sensor or the like, and outputs it to the gripping control unit 313.

  The screw tightening control unit 314 controls the screw tightening operation for the screw tightening mechanism 325. The screw tightening mechanism 325 includes a moving mechanism (X, Y, and Z) that moves the electric driver to a screw tightening position of the work W, such as an electric driver that performs screw tightening on the work W, and a screw supply unit that automatically supplies screws to the electric driver. 3 axis actuator). The screw tightening mechanism 325 uses a plurality of screws (for example, twelve) 222 per work W, inserts the screw 222 into each screw position of the work W, and rotates the screw tightening driver to rotate the work W (heat sink for the housing 201). 202) is sequentially performed.

  FIG. 4 is a block diagram illustrating a hardware configuration example of the screw tightening device according to the first embodiment. The screw tightening device 100 includes a CPU 401, a ROM 402, a RAM 403, an input / output interface (IF) 404, a keyboard 405, a display IF 406, a display 407, a communication IF 408, and the like.

  For example, the CPU 401 executes a control program stored in the ROM 402 to realize the function of the screw tightening apparatus 100. At this time, the CPU 401 uses a part of the RAM 403 as a work area. The input / output IF 404 is an interface for inputting a set value using the keyboard 405 or a mouse or the like and outputting an operation state of the screw tightening apparatus 100. The display IF 406 is an interface that displays and outputs the operation state of the screw tightening apparatus 100 on the display 407. The communication IF 408 is an interface that communicates setting values and operation states of the screw tightening device 100 with an external device via a predetermined communication IF.

  Each function of the control unit 301 shown in FIG. 3 can be realized by executing the program of the CPU 401 shown in FIG. 4 including the CPU 401, the keyboard 405, and the display 407 can be provided in the screw tightening unit 103 portion. In this case, the keyboard 405 and the display 407 can be configured by touch panels and can be miniaturized.

  5 is a front view showing the screw tightening device of the first embodiment, FIG. 6 is a top perspective view showing the screw tightening unit of the screw tightening device of the first embodiment, and FIG. 7 is a bottom perspective view of the same. As shown in FIG. 5, an upper base 502 is suspended by a pulley 501 on a rail 102 provided along the conveyance direction X of the workpiece W, and the upper base 502 is movable in the conveyance direction X by a motor (not shown). .

  In addition, the upper base 502 is provided with a motor 503, a plurality of pulleys 504, a wire 505, and a lower base 506 that constitute an elevating mechanism 321. The lower base 506 moves up and down by winding the wire 505 by the rotation of the motor 503. The elevating control unit 312 controls the lower base 506, that is, the screw fastening unit 103, by controlling the rotation of the motor 503.

  The lower base 506 of the screw tightening unit 103 is formed with an opening 506a having a wide vertical and horizontal dimension that is larger than the outer diameter of the workpiece W, that is, the protruding portion 211 of the housing 201. When the screw tightening unit 103 is lowered, the workpiece W can pass through the opening 506a portion, and the protruding portion 211 of the workpiece W can be positioned on the upper surface of the lower base 506. The lowering position of the screw tightening unit 103 is detected by a lowering position confirmation sensor 510 (see FIG. 6) that constitutes the raising / lowering detection unit 322, and is controlled so as to be a specified height position.

  On the lower surface of the lower base 506, four extendable legs 512 that are extendable in the vertical direction Z are provided. On the upper surface of the lower base 506, two protruding support claws 513 are provided for each side of the opening 506a. In the following description, among the parts including the support claws 513, those arranged in the left-right direction X are given a suffix x, and those arranged in the front-rear direction Y are given a suffix y.

  The support claws 513 (513x, 513y) can be protruded in the direction of the opening 506a by grip cylinders 525 (525x, 525y) constituting the grip mechanism 323, respectively. The support claws 513 enter the lower surface of the protruding portion 211 of the casing 201 of the workpiece W and support the workpiece W.

  Further, in the front-rear direction Y of the opening 506a, two fixed blocks 514y fixed to the lower base 506 are provided on the back side of the opening 506a, and two movable blocks 515y are provided on the front side. Further, in the left-right direction X of the opening 506a, two fixing blocks 514x fixed to the lower base 506 are provided on the right side (conveying direction X side) of the opening 506a, and the left side (conveying direction X front side). Are provided with two movable blocks 515x.

  The fixing block 514 (514x, 514y) is fixed to a reference position (reference position for screw tightening) of the screw tightening unit 103 for fixing (gripping position) of the workpiece W. That is, the fixed block 514 (514x, 514y) is accurately attached to the coordinate axis of the three-axis actuator 531. Accordingly, by pressing the workpiece W against the fixed block 514, the reference positions X and Y of the workpiece W can be correctly positioned with respect to the axis reference of the robot.

  The movable block 515x is attached to the holding cylinder 525x together with the support claw 513x. The movable block 515y is attached to the holding cylinder 525y together with the support claw 513y.

  The fixed block 514 and the movable block 515 hold the side portion of the workpiece W. More specifically, the fixed block 514 and the movable block 515 are provided at positions in contact with the protruding portion 211 of the housing 201 of the workpiece W and the side surface of the heat sink 202.

  The movable block 515 (515x, 515y) is provided on the rod of the grip cylinder 525 (525x, 525y), and grips the workpiece W by moving in the direction of the opening 506a by the extension of the rod. At this time, the movable block 515 comes in contact with the workpiece W, moves the workpiece W in the left-right direction X and the front-rear direction Y, and presses the workpiece W against the fixed block 514 (514x, 514y). The position of (X, Y) can be fixed at the screw tightening reference position.

  The rods of the gripping cylinders 525 (525x, 525y) are each provided with eight pressing cylinders 517 (517x, 517y) for pressing the workpiece W from above, two on each side of the opening 506a.

  FIG. 8 is a partially enlarged perspective view of the screw tightening unit of the screw tightening device according to the first embodiment. The pressing cylinder 517 is provided with a pressing piece 801 (801x, 801y) at the rod tip. The pressing pieces 801 (801x, 801y) are provided at positions facing the support claws 513 (513x, 513y). The support claw 513 and the pressing piece 801 are provided at a position where they do not interfere with the attachment portion (screw holes 212 and 221) of the screw 222 of the workpiece W.

  The holding control unit 313 extends and holds the rod of each pressing cylinder 517 (517x, 517y) after fixing and holding the side portion of the workpiece W by the fixed and movable blocks 514 and 515. Thereby, the pressing piece 801 (801x, 801y) presses the upper surface (protrusion part) of the heat sink 202 of the workpiece W from above. Then, the heat sink 202 can be pressed from above with the packing 203 sandwiched between the casing 201 in which the protruding portions 211 are supported by the support claws 513 (513x, 513y). At this time, the packing 203 provided on the entire circumference of the workpiece W can be pressed with a uniform force, the tilt of the workpiece W (heat sink 202) can be prevented, and the subsequent screw tightening can be easily performed.

  A plate member 520 is fixed to the rod of the grip cylinder 525 (525x, 525y) (see FIGS. 5, 6, and 8). The plate member 520 is provided with a support claw 513 (513x, 513y), a movable block 515 (515x, 515y), and a pressing cylinder 517 (517x, 517y).

  Further, on the lower base 506, a triaxial actuator 531 constituting a screw fastening mechanism 325 and an electric driver 532 are provided. The three-axis actuator 531 includes a Y-axis slider 531y on the movable part of the X-axis slider 531x and includes a Z-axis slider 531z on the movable part of the Y-axis slider 531y. An electric driver 532 is provided on the movable portion of the Z-axis slider 531z.

  Then, the electric screwdriver 532 can be moved to each screw tightening position of the workpiece W under the control of the screw tightening control unit 314. The electric driver 532 has a rotatable driver shaft 533 that faces downward along the height direction Z. With the screw 222 attached to the tip of the driver shaft, the screw 222 is screwed into the screw hole 212 of the housing 201 through the screw hole 221 by rotating the driver shaft at the screw hole 221 portion of the workpiece W. The heat sink 202 can be fastened and fixed to 201.

(Example of screw tightening operation for a workpiece that does not move on the carriage)
Next, operation | movement of the screw fastening apparatus of Embodiment 1 is demonstrated. 9-16 is a front view explaining the operation | movement procedure of the screw fastening apparatus of Embodiment 1. FIG. In the following description, an example where the workpiece W is placed on the carriage 150 and does not move will be described.

  First, in the initial state shown in FIG. 9, the control unit 301 of the screw tightening apparatus 100 stands by at the initial position, and the elevating control unit 312 waits the screw tightening unit 103 at the upper position of the workpiece W.

  Then, a position sensor or the like detects whether the workpiece W is positioned at the screw fastening device 100, that is, the opening 506a of the lower base 506, and the workpiece W is positioned at the opening 506a portion of the lower base 506. The relative positioning of the screw tightening device 100 with respect to the workpiece W may be performed by moving the screw tightening unit 103 along the rail 102 or moving the carriage 150.

  Then, as shown in FIG. 10, the control unit 301 (elevation control unit 312) rotates the motor of the elevating mechanism 321 to lower the screw fastening unit 103 in the direction of the workpiece W. At this time, the control unit (elevation control unit 312) detects the lowering of the screw tightening unit 103 (lower base 506) by the lowering position confirmation sensor 510, and stops at a predetermined position where the telescopic leg 512 is not in contact with the carriage 150. Let In addition, the specified position is set such that the protruding portion 211 of the housing 201 of the workpiece W is located above the support claw 513. For example, when the descent position confirmation sensor 510 (see FIG. 6) detects contact of the workpiece W with the heat sink 202, the sensor is turned on, and the elevation control unit 312 stops the descent of the screw tightening unit 103.

  Next, as shown in FIG. 11, the control unit 301 (gripping control unit 313) extends the rod of the gripping cylinder 525 (525x, 525y) and moves the support claw 513 below the protruding portion 211 of the casing 201 of the workpiece W. Get in. As a result, the workpiece W can be gripped by the support claws 513 (513x, 513y) of the screw tightening unit 103 so that the workpiece W can be lifted from the carriage 150. Further, the workpiece W is lowered by its own weight, and the projection 211 is placed on the support claw 513, so that the horizontal reference of the workpiece W can be matched (determined) with the horizontal reference of the screw tightening unit 103.

  Then, the grip control unit 313 further extends the rod of the grip cylinder 525 and presses the movable block 515 (515x, 515y) in the direction of the workpiece W. As a result, the movable block 515x presses the workpiece W in the direction of the fixed block 514x that is the reference position in the left-right direction X. Further, the movable block 515y presses (buts against) the work W with a predetermined force (first pressing force) in the direction of the fixed block 514y that is the reference position in the front-rear direction Y. Thereby, the workpiece | work W can be positioned in the X and Y position used as the reference | standard of the screw fastening unit 103. FIG. For example, the first pressing force is not a force for firmly gripping the workpiece W, but a force that allows the workpiece W to slide down by its own weight.

  In addition, when the workpiece W is gripped by the fixed block 514 and the movable block 515, it is desirable that the support claws 513 have a dimensional difference that does not touch the workpiece W. However, when the workpiece W is gripped by the fixed block 514 and the movable block 515, the support claw 513 is dimensioned to be positioned below the protruding portion 211 of the casing 201 of the workpiece W, thereby preventing the workpiece W from falling off. it can.

  Next, as shown in FIG. 12, the control unit 301 (elevation control unit 312) extends the extendable leg 512. As a result, the workpiece W is lifted from the carriage 150 while the workpiece W is gripped by the screw tightening unit 103.

  Next, as shown in FIG. 13, the control unit 301 (gripping control unit 313) has a force larger than the first pressing force performed in FIG. 11 after the horizontal reference of the workpiece W with respect to the screw tightening unit 103 is determined. The workpiece W is pressed with (second pressing force) (rebutting). The first pressing force is such that the workpiece W slides down due to the weight of the workpiece W, so that the protruding portion 211 of the workpiece W is brought into close contact with the support claw 513 and the workpiece W is positioned in the height direction Z. It can be performed.

  If the first pressing force alone is applied with a large force from the beginning, the workpiece W may be left floating (tilted), and the protruding portion 211 of the workpiece W may not be lowered to its supporting claw 513 by its own weight. To prevent this, a two-step butt is performed. Not limited to this, the gripping control unit 313 extends the gripping cylinder 525, presses the workpiece W against the fixed block 514 with a first pressing force by the movable block 515, and then slightly contracts the gripping cylinder 525 to The pressing force of 1 may be weakened.

  By gripping the workpiece W with the first pressing force, the protruding portion 211 is placed on the support claw 513, and the horizontal plane of the workpiece W can be matched with the support claw 513, that is, the horizontal plane (horizontal reference) of the apparatus. Thereafter, the work W may be strongly held with the second pressing force again. At this time, since the distance between the movable block 515 and the fixed block 514 may be slightly changed, only one gripping cylinder 525 (525x, 525y) to which the movable block 515 (515x, 515y) is attached is contracted. And may be elongated.

  By the operations of the lifting mechanism 321 and the gripping mechanism 323 described above, the workpiece W can be lifted from the carriage 150 and the position of the workpiece W can be adjusted to the reference position (X, Y position) of the screw tightening unit 103. Thereby, even when the carriage 150 on which the workpiece W is placed and other carriages, facilities, etc. are not horizontal with respect to the floor surface, the positioning of the workpiece W to the reference position of the screw tightening unit 103 can be performed. The subsequent screw tightening operation can be performed smoothly.

  Next, as shown in FIG. 14, the control unit 301 (gripping control unit 312) holds the pressing cylinders 517 (517x, 517y) in a state where the side portions of the workpiece W are fixed and held by the fixed and movable blocks 514 and 515. ) To extend the rod. Thereby, the pressing piece 801 (801x, 801y) presses the upper surface (protrusion part) of the heat sink 202 of the workpiece W from above.

  Accordingly, the heat sink 202 can be pressed from above with the packing 203 sandwiched between the casing 201 in which the protruding portion 211 is supported by the support claws 513 (513x, 513y). At this time, the packing 203 provided on the entire circumference of the workpiece W is pressed with a uniform force.

  Next, as shown in FIG. 15, the control unit 301 (robot control unit 311) drives the three-axis actuator 531 of the screw tightening mechanism 325 to move the electric driver 532 over the screw tightening position (screw hole 221) of the workpiece W. Move to. At this time, the robot control unit 311 operates the three-axis actuator 531 to move it in the front-rear and left-right directions (each direction of the horizontal plane) X and Y, and sequentially moves the electric driver 532 to a plurality of screw tightening locations of the workpiece W. .

  Then, the robot control unit 311 positions the electric driver 532 at each screw tightening location. Thereafter, the screw 222 supplied from the screw supply unit is attached to the tip of the driver shaft, the driver shaft 533 is lowered into the screw hole 221 portion of the workpiece W, and the screw 222 is inserted into the screw hole 221. Then, the screw tightening control unit 314 rotates the driver shaft 533 while the robot control unit 311 lowers the electric driver 532. As a result, the screw 222 inserted into the screw hole 221 of the workpiece W is screwed into the screw hole 212 of the housing 201, and the heat sink 202 can be fastened and fixed to the housing 201.

  At this time, the packing 203 provided on the entire circumference of the work W is pressed with a uniform force by the pressing pieces 801 (801x, 801y), and the work W is temporarily moved without the heat sink 202 being inclined with respect to the housing 201. It is fixed. Thereby, the screw can be tightened in a state where the axis of the screw 222 is aligned with the axis of the screw hole 212. At this time, the screw can be correctly tightened without causing idling of the driver, screw biting, screw head crushing, or the like.

  Here, in the existing technology, when there are a plurality of screw tightening points, the screw tightening points are dispersed, for example, the screw tightening of the diagonal points is sequentially performed, and a plurality of screw tightening is performed per one place (increase) Tighten). On the other hand, in Embodiment 1, since the packing 203 of the workpiece W is uniformly suppressed over the entire circumference of the workpiece W, even if the screw tightening at one location is performed, the screw tightening portion at another location is lifted. (Inclination of the heat sink 202) can be prevented. Therefore, even if the screw tightening is completed for each place, there is no variation in the screw tightening torque.

  As a result, the machine cycle time required for the screw tightening operation can be shortened, and the screw can be efficiently tightened. In the above description, the example in which the workpiece W has the packing 203 has been described. However, in the workpiece W that does not have the packing 203, additional tightening is similarly unnecessary, and screw tightening locations can be completed one by one.

  FIG. 16 is a diagram illustrating a state after the screw tightening of the workpiece W is completed. When the screw tightening of the workpiece W is completed, the control unit 301 returns the screw tightening mechanism 325 and the gripping mechanism 323 to an initial position away from the workpiece W. At this time, the screw tightening mechanism 325 moves the electric driver 532 away from the workpiece W to the upper position Z, and returns the triaxial actuator 531 to the initial position (X, Y, Z) of the origin.

  Thereafter, the control unit 301 contracts the telescopic legs 512 to the initial position, contracts the telescopic legs 512 of the elevating mechanism 321, and lowers the workpiece W onto the carriage 150. Thereafter, the pressing cylinder 517 of the gripping mechanism 323 is contracted to release the pressing piece 801 in the upper direction Z of the workpiece W. Then, the gripping cylinder 525 is contracted, and the fixed block 514, the movable block 515, and the support claw 513 are separated from the workpiece W in the front-rear and left-right directions X and Y. Thereafter, the motor 503 of the lifting mechanism 321 is rotated to raise the screw fastening unit 103. Accordingly, as shown in FIG. 16, the workpiece W lifted by the screw tightening unit 103 is again lowered onto the carriage 150, and can be made free with respect to the screw tightening unit 103.

(Positioning operation when the cart or screw tightening device is tilted)
Next, the positioning operation of the workpiece W when the carriage 150 or the screw fastening device 100 is not in a horizontal state will be described. 17A and 17B are front views showing the workpiece positioning operation in the state where the carriage is tilted in the first embodiment. In these figures, for the sake of convenience, the tilt of the carriage 150 is shown as a large tilt state so that it can be easily understood.

  As shown in FIG. 17A, it is assumed that the workpiece W on the carriage 150 is inclined from the horizontal state due to the inclination of the carriage 150. In this case, the control unit 301 of the screw tightening device 100 lowers the screw tightening unit 103 to lower the support claw 513 to a position lower than the protruding portion 211 of the workpiece W. Then, the screw tightening unit 103 extends the gripping cylinder 525 so that the support claw 513 enters the protruding portion 211 of the workpiece W.

  Thereafter, as illustrated in FIG. 17B, the control unit 301 can tilt the screw fastening unit 103 in accordance with the tilt of the carriage 150 by extending the telescopic legs 512.

  Thereafter, the control unit 301 extends the gripping cylinder 525 and grips the workpiece W by the fixed block 514 and the movable block 515. Subsequent operations are the same as described above. Note that, as shown in FIG. 17B, the screw tightening can be completed even when the screw tightening unit 103 remains inclined.

  18A and 18B are front views showing a workpiece positioning operation in a state where the screw fastening device is inclined in the first embodiment. For example, it is assumed that the screw fastening device 100 is installed in a state inclined from the horizontal due to an error during assembly of the equipment.

  As shown in FIG. 18A, it is assumed that the screw tightening unit 103 of the screw tightening device 100 is inclined from the horizontal state. Even in this case, the control unit 301 of the screw tightening device 100 lowers the screw tightening unit 103 in the same manner as described above, and lowers the support claw 513 to a position lower than the protruding portion 211 of the workpiece W. The screw tightening unit 103 extends the gripping cylinder 525 and presses it with the first pressing force by the fixed block 514 and the movable block 515, and causes the support claw 513 to enter the protruding portion 211 of the workpiece W.

  Thereafter, as shown in FIG. 18B, the control unit 301 can extend the telescopic leg 512 to level the screw fastening unit 103 in accordance with the horizontal state of the carriage 150. Even if the carriage 150 is not strictly horizontal, the screw tightening unit 103 and the coordinate axes X, Y, and Z of the workpiece W can be made to coincide with each other, and the screws can be tightened correctly.

  Thereafter, the control unit 301 extends the gripping cylinder 525 and grips the workpiece W with the second pressing force by the fixed block 514 and the movable block 515. The subsequent operation is the same as described above.

  FIG. 19 is a diagram illustrating a state when the workpiece is tightened by the screw tightening device according to the first embodiment. The enlarged view of the electric screwdriver 532 of the screw fastening apparatus 100 and the screw hole 212 part of the workpiece | work W is shown. As shown in this figure, for example, when the workpiece W is tilted by the tilt of the carriage 150, the screw tightening unit 103 of the screw tightening device 100 has the same tilt corresponding to the tilt of the workpiece W.

  The screw tightening unit 103 floats the workpiece W by the telescopic legs 512 and lifts it from the mounting surface, thereby matching the reference coordinates X, Y, Z of the workpiece W with the reference coordinates of the screw tightening device 100 (screw tightening unit 103). be able to. Here, the screw tightening device 100 determines the coordinates of the workpiece W on relative coordinates based on the screw tightening device 100 (screw tightening unit 103), not on absolute coordinates with respect to the floor surface or the upper surface of the carriage 150. Thereby, even if there is a concavo-convex state of the carriage 150 and a state in which the screw tightening device 100 is tilted from the horizontal, the screw can be correctly tightened without being affected by these concavo-convexities and tilts.

  As described above, the screw fastening device 100 according to the first embodiment can match the coordinate axes X, Y, and Z of the workpiece W and the screw fastening unit 103 even when the carriage 150 or the screw fastening device 100 is inclined. Can be screwed correctly.

(Application example for intermittent conveyance of workpieces by conveyor)
The above description is based on the assumption that the workpiece W is fixed on the carriage 150. However, the screw tightening device 100 according to the first embodiment causes the conveyor 150 to convey the workpiece W in the conveyance direction (left-right direction) X. The same applies to the configuration.

  FIG. 20 is a front view illustrating a workpiece conveyance state of the screw tightening apparatus according to the first embodiment. On the conveyor 150, for example, a plurality of workpieces W are placed at predetermined intervals. The screw tightening device 100 operates in the same manner as in the case of the workpiece W fixed by the above-described carriage every time the workpiece W stops at the grip portion of the device. The conveyor 150 repeats the operation of conveying and stopping the workpiece W by an intermittent operation. When the workpiece W by such an intermittent operation is positioned at a predetermined position, the screw tightening device 100 can perform screw tightening on the plurality of workpieces W conveyed by the conveyor 150.

  FIG. 21A to FIG. 21C are flowcharts illustrating an operation procedure of the screw tightening device according to the first exemplary embodiment. An example of an operation performed by each function of the control unit 301 on the workpiece W conveyed by the conveyor 150 will be described.

  First, the control unit 301 performs an initialization process (step S2101), and outputs a conveyor movement signal to the conveyor 150 (step S2102). Thereby, the conveyor 150 moves the workpiece W in the transport direction X. Next, the control unit 301 waits for a movement completion signal output from the conveyor 150 (step S2103: No loop). When the movement completion signal is detected (step S2103: Yes), the workpiece W is positioned directly below the screw tightening unit 103.

  Thereafter, when the operation button for starting screw tightening is operated (step S2104), the control unit 301 starts controlling the screw tightening operation by the screw tightening device 100. First, the control unit 301 lowers the screw tightening unit 103 (step S2105) and waits for the lowering position confirmation sensor 510 to detect (step S2106: No loop).

  For example, when the lowering position confirmation sensor 510 comes into contact with the workpiece W when the screw tightening unit 103 is lowered (step S2106: Yes), the control unit 301 then extends the front and rear, right and left grip cylinders 525. It strikes (step S2107). Thereby, the protrusion part 211 of the workpiece | work W will be mounted on the support nail | claw 513, and the screw fastening unit 103 will be in the state which can lift the workpiece | work W from a mounting surface. The expansion / contraction state of the front / rear / right / left grip cylinder 525 is detected by the abutment confirmation sensor (step S2108). For example, the abutment confirmation sensor waits for a state in which the workpiece W is gripped by the first pressing force between the fixed block 514 and the movable block 515 described above (step S2108: No loop), and detects the gripping state ( Step S2108: Yes).

  Thereafter, the control unit 301 causes the screw tightening unit 103 to float (rise) (step S2109). And the control part 301 confirms whether it has extended to the predetermined amount which the expansion-contraction leg sensor provided in the expansion-contraction leg 512 prescribed | regulated (step S2110: No loop). When the extension of the extendable leg 512 by the extendable leg sensor is confirmed (step S2110: Yes), the control unit 301 extends the pressing cylinder 517 and presses the work W (heat sink 202) from above with the pressing piece 801 (step S2111). The control unit 301 waits for detection of the pressing state by the heat sink pressing confirmation sensor (step S2112: No loop). By this pressing, the packing 203 is uniformly crushed.

  When the control unit 301 confirms the pressing (step S2112: Yes), the control unit 301 abuts a high load (second pressing force) against the front, rear, left and right gripping cylinders 525 (step S2113). The abutting state is detected by the front / rear / right / left abutting confirmation sensor (step S2114: No loop). When the load becomes the second pressing force (step S2114: Yes), the workpiece W is firmly fixed between the fixed block 514 and the movable block 515 with the second pressing force.

  Next, the control unit 301 performs screw tightening on the workpiece W by the electric driver 532 (step S2115). At this time, the control unit 301 controls the three-axis actuator 531, positions the electric driver 532 at the screw tightening position of the work W, and fastens the work W with the screw 222.

  Thereafter, the control unit 301 determines screw floating at the screw tightening location (step S2116). For example, if a screw lift in which screw tightening is not correctly completed is detected based on the operating state of the electric driver 532 (detection of idling or load state of the driver shaft 533) (step S2116: NG), the workpiece W is screw tightened. It is determined that the product is in error. Then, error processing such as removing the workpiece W in error is performed (step S2117), and the process proceeds to step S2118. If no screw lift is detected (step S2116: OK), the control unit 301 completes the above screw tightening operation.

  Then, when the operation button is pressed based on the completion of screw tightening (step S2118), the control unit 301 releases the floating of the screw tightening unit 103 (step S2119). As a result, the workpiece W is lowered from the screw tightening unit 103 onto the placement surface on the conveyor 150. At this time, when the control unit 301 contracts the extendable leg 512 (step S2120: No loop) and confirms that the extendable leg 512 contracts to the initial state (step S2120: Yes), the process proceeds to step S2121.

  Then, the control unit 301 contracts the pressing cylinder 517 to release the pressing of the work W (heat sink 202) by the pressing piece 801 (step S2121), and waits for detection of the heat sink pressing release confirmation sensor (step S2122: No loop). ). When the pressing release by the heat sink pressing release confirmation sensor is detected (step S2122: Yes), the control unit 301 contracts the front, rear, left, and right holding cylinders 525, and grips (buts against) the workpiece W by the fixed block 514 and the movable block 515. ) Is released (step S2123). Then, the detection of the front / rear / left / right butting release sensor is awaited (step S2124: No loop).

  When the butt release by the front / rear / left / right butt release sensor is detected (step S2124: Yes), the control unit 301 raises the screw tightening unit 103 (step S2125). Then, it waits for the screw tightening unit 103 to rise to the detection position (initial position) of the rising position confirmation sensor (step S2126: No loop). When the lift position of the screw tightening unit 103 is detected by the lift position confirmation sensor (step S2126: Yes), the screw tightening unit 103 is retracted upward with respect to the workpiece W.

  Then, the control unit 301 determines whether or not to continue the screw tightening operation on the workpiece W after the screw tightening on the workpiece W is completed (step S2127). If there is a next work W to be tightened, the control unit 301 determines that the work is continued (step S2127: Yes), and returns to the process of step S2102. On the other hand, if there is no next workpiece W to be screwed, the control unit 301 determines that the work is finished (step S2127: No), and finishes the above series of operations.

  According to the first embodiment described above, the workpiece can be positioned at the reference position of the screw tightening unit by lifting it from the mounting surface while supporting the projecting portion of the workpiece with the support claws of the screw tightening unit. Accordingly, even if the carriage is inclined or the mounting surface of the screw tightening device is inclined, the workpiece can be correctly screwed. Each time the workpiece is placed on the carriage or stopped by intermittent conveyance by a conveyor, the screw tightening unit can lift and tighten the workpiece.

(Embodiment 2)
22 and 23 are front views showing the screw tightening device of the second embodiment. In the second embodiment, an application example to a configuration in which the conveyor 150 continuously conveys the workpiece W will be described. The screw fastening apparatus 100 described in FIG. 22 has the same configuration as that of the first embodiment (see FIG. 5), and the same portions are denoted by the same reference numerals. In the second embodiment, the conveyor 150 does not stop while a plurality of workpieces W are placed, and continuously conveys and moves the workpieces W in the conveyance direction X.

  The screw tightening device 100 can be applied to such continuous conveyance of the workpiece W. As described above, in the screw tightening device 100, the screw tightening unit 103 is suspended by the rail 102, and is movable between the predetermined length X1 along the conveyance direction X of the workpiece W.

  Therefore, in the second embodiment, the control unit 301 moves the screw tightening unit 103 in the transport direction X in synchronization with the conveyor 150 between the predetermined lengths X1. For example, as illustrated in FIG. 22, it is assumed that the conveyor 150 transports the workpiece W and the workpiece W reaches the initial position (start position) of the screw tightening unit 103. At this time, the control unit 301 moves the screw tightening unit 103 in the transport direction X at a speed M synchronized with the speed M of the workpiece W (conveyor 150). As a result, the workpiece W and the screw tightening unit 103 move in the transport direction X at the same speed with no speed difference.

  Then, as shown in FIG. 23, the control unit 301 lowers the screw tightening unit 103 by the lifting mechanism 321 while moving the screw tightening unit 103 at the speed M in the transport direction X, and moves the workpiece W by the gripping mechanism 323. Grip. Thereafter, the screw tightening unit 103 is lifted by the lifting mechanism 321 (extension of the extendable leg 512) to lift the workpiece W from the placement surface.

  As described in the first embodiment, the lifting mechanism 321 includes the motor 503, the wire 505, and the like. The gripping mechanism 323 includes a support claw 513, front and rear grip cylinders 525 and a fixed block 514, a movable block 515, a pressing cylinder 517 and a pressing piece 801, an extendable leg 512, and the like.

  Then, the control unit 301 moves the three-axis (X, Y, Z) by the three-axis actuator 531 of the screw tightening mechanism 325 with respect to the workpiece W positioned with respect to the screw tightening unit 103 by the gripping mechanism 323. By 532, the screw tightening of each screw tightening point is performed. Thereafter, the control unit 301 lowers the elevating mechanism 321, and the gripping mechanism 323 is retracted from the work W so that the work W for which the screw tightening is completed is placed on the conveyor 150 again.

  Then, the control unit 301 lifts the workpiece W on the conveyor 150, completes the positioning and screw tightening of the workpiece W, and again puts the workpiece W on the conveyor 150 (period T). May be moved in synchronization with the conveyor 150. What is necessary is just to set the length of the conveyance direction of the rail 102 according to the period T and the speed M of the conveyor 150. FIG.

  The control unit 301 puts the workpiece W on which the screw tightening has been completed on the conveyor 150, and then returns the screw W to the initial position by reversing the conveying direction X. It can be carried out.

  24A to 24C are flowcharts illustrating the operation procedure of the screw tightening apparatus according to the second embodiment. The operation example which each function of the control part 301 performs about each workpiece | work W which the conveyor 150 continuously conveys at a fixed speed is shown.

  First, the control unit 301 performs an initialization process (step S2401), and moves the screw tightening unit 103 to a position above the workpiece W along the rail 102 (step S2402). Thereafter, the control unit 301 moves the screw tightening unit 103 in synchronization with the conveyor 150 (step S2403). Here, when the conveyor 150 stops or the speed fluctuates, the control unit 301 may stop the moving speed of the screw tightening unit 103 in synchronization with the speed of the conveyor 150 or change the speed.

  Thereafter, when the operation button for starting screw tightening is operated (step S2404), the control unit 301 starts controlling the screw tightening operation by the screw tightening device 100. First, the control unit 301 lowers the screw tightening unit 103 (step S2405) and waits for the lowering position confirmation sensor 510 to detect (step S2406: No loop).

  When the screw tightening unit 103 is lowered, an operator may finely adjust the lowering position of the screw tightening unit 103 according to the position of the workpiece W moving on the conveyor 150 at a constant speed.

  Then, when the lowering position confirmation sensor 510 comes into contact with the workpiece W when the screw tightening unit 103 is lowered (step S2406: Yes), the control unit 301 then extends the front, rear, left and right grip cylinders 525. It strikes (step S2407). Thereby, the protrusion part 211 of the workpiece | work W will be mounted on the support nail | claw 513, and the screw fastening unit 103 will be in the state which can lift the workpiece | work W. FIG. The expansion / contraction state of the front / rear left / right grip cylinder 525 is detected by the abutment confirmation sensor (step S2408). For example, the abutment confirmation sensor waits for a state in which the workpiece W is gripped by the first pressing force between the fixed block 514 and the movable block 515 (step S2408: No loop), and detects the gripping state ( Step S2408: Yes).

  Thereafter, the control unit 301 causes the screw tightening unit 103 to float (rise) (step S2409). And the control part 301 confirms whether it has extended to the predetermined amount which the expansion-contraction leg sensor provided in the expansion-contraction leg 512 prescribed | regulated (step S2410: No loop). When it is confirmed that the extendable leg is extended by the extendable leg sensor (step S2410: Yes), the control unit 301 extends the pressing cylinder 517 and presses the work W (heat sink 202) from above with the pressing piece 801 (step S2411). The control unit 301 waits for detection of the pressing state by the heat sink pressing confirmation sensor (step S2412: No loop). By this pressing, the packing 203 is uniformly crushed.

  When the control unit 301 confirms the pressing (step S2412: Yes), the control unit 301 abuts a high load (second pressing force) against the front, rear, left and right gripping cylinders 525 (step S2413). The abutting state is detected by the front / rear / left / right abutting confirmation sensor (step S2414: No loop). When the load becomes the second pressing force (step S2414: Yes), the workpiece W is firmly fixed between the fixed block 514 and the movable block 515 with the second pressing force.

  Next, the control unit 301 performs screw tightening on the workpiece W by the electric driver 532 (step S2415). At this time, the control unit 301 controls the three-axis actuator 531, positions the electric driver 532 at the screw tightening position of the work W, and fastens the work W with the screw 222.

  Thereafter, the control unit 301 determines screw floating at the screw tightening location (step S2416). For example, if a screw lift in which screw tightening is not correctly completed is detected based on the operating state of the electric driver 532 (detection of idling or load state of the driver shaft 533) (step S2416: NG), the workpiece W is screw tightened. It is determined that the product is in error. Then, error processing such as removing the workpiece W in error is performed (step S2417), and the process proceeds to step S2418. If no screw lift is detected (step S2416: OK), the control unit 301 completes the above screw tightening operation.

  Then, when the operation button is pressed based on the completion of screw tightening (step S2418), the control unit 301 releases the floating of the screw tightening unit 103 (step S2419). As a result, the workpiece W is lowered onto the conveyor 150. At this time, when the control unit 301 contracts the telescopic leg 512 (step S2420: No loop) and confirms that the telescopic leg 512 contracts to the initial state (step S2420: Yes), the process proceeds to step S2421.

  Then, the control unit 301 contracts the pressing cylinder 517 to release the pressing of the work W (heat sink 202) by the pressing piece 801 (step S2421), and waits for the detection of the heat sink pressing release confirmation sensor (step S2422: No loop). . When the pressing release by the heat sink pressing release confirmation sensor is detected (step S2422: Yes), the control unit 301 contracts the front, rear, left, and right holding cylinders 525, and grips (buts against) the workpiece W by the fixed block 514 and the movable block 515. ) Is released (step S2423). Then, the detection of the front / rear / right / left butting release sensor is awaited (step S2424: No loop).

  When the butt release by the front / rear / left / right butt release sensor is detected (step S2424: Yes), the control unit 301 raises the screw tightening unit 103 (step S2425). Then, it waits for the screw tightening unit 103 to rise to the detection position (initial position) of the rising position confirmation sensor (step S2426: No loop). When the rising position of the screw tightening unit 103 is detected by the lift position confirmation sensor (step S2426: Yes), the screw tightening unit 103 is retracted upward with respect to the workpiece W.

  Then, the control unit 301 determines whether or not to continue the screw tightening operation on the workpiece W after the screw tightening on the workpiece W is completed (step S2427). If there is a next work W to be screwed, the control unit 301 determines that the work is continued (step S2427: Yes), and returns to the process of step S2402. At this time, the control unit 301 moves the screw tightening unit 103 in the direction opposite to the conveying direction of the conveyor 150 to return to the initial position. On the other hand, if there is no next work W to be screwed, the control unit 301 determines that the work is finished (step S2427: No), and finishes the above series of operations.

  According to the second embodiment described above, as in the first embodiment, the workpiece is lifted from the mounting surface in a state in which the projecting portion of the workpiece is supported by the support claws of the screw tightening unit, so that the workpiece is moved to the reference position of the screw tightening unit. Can be positioned. Accordingly, even if the carriage is inclined or the mounting surface of the screw tightening device is inclined, the workpiece can be correctly screwed. And even if it is the workpiece | work on the conveyor conveyed continuously at a fixed speed like Embodiment 2, screwing can be performed, moving, by moving a screw fastening unit synchronizing with a conveyor.

  In this manner, by moving the screw tightening unit in synchronization with the conveyor, the work can be screwed regardless of the moving state of the conveyor or the stopped state. Furthermore, according to Embodiment 2, it is not limited to waiting for the next workpiece to flow directly below the screw tightening unit to a predetermined position (the start position). For example, a series of operations of screw tightening for the next workpiece W may be started by moving to a conveyance direction other than the start position.

  Thereby, if there is no abnormality like a fixed position stop conveyor, the screw | screw of the workpiece | work conveyed with the conveyor which is always moving can be performed now. In addition, even if the conveyor stops due to abnormalities or work delays in other work processes, it is necessary to interrupt the screw tightening operation since the screw tightening unit can be stopped in synchronization with this. The screw tightening operation can be continued. Thereby, the screw fastening with respect to a some workpiece | work can be performed more efficiently.

(Embodiment 3)
25 and 26 are front views showing the screw tightening device of the third embodiment. In the screw fastening device 100 according to the third embodiment, the same components as those in the first embodiment (see FIG. 5) are denoted by the same reference numerals. The third embodiment is different in that a balancer 2501 is used as the lifting mechanism 321 instead of the motor 503.

  The balancer 2501 is provided at each of the corner portions (four corners) of the screw tightening unit 103, and the length of the wire 505 is variable. By providing the balancer 2501 in this way, the weight of the screw tightening unit 103 can be canceled, and when the screw tightening unit 103 is raised upward, it can be stopped at an arbitrary position. Further, the motor 503 and the like can be moved up and down without the need for power, and the operator can freely move it. Further, since the wire length of the wire 505 can be individually adjusted for each balancer 2501, the screw tightening unit 103 can be easily positioned according to the inclination of the carriage or the conveyor 150 as shown in FIG.

  Also in the third embodiment, the mechanisms other than the balancer 2501 are the same as those in the respective embodiments, and it is possible to obtain the effect of being able to perform screw fastening correctly as in the respective embodiments.

  According to each embodiment described above, the projecting portion of the workpiece is placed on the support claw of the screw tightening unit and lifted, whereby the horizontal direction of the workpiece can be matched with the horizontal plane of the screw tightening unit and the height direction can be positioned. As a result, even if the workpiece is tilted due to unevenness on the workpiece mounting surface, the screw tightening unit can correctly tighten the screw on the positioned workpiece without causing driver slippage, screw engagement, screw head crushing, etc. become.

  Further, by controlling the pressing force at the time of gripping the workpiece in stages, the protruding portion of the workpiece can be brought into close contact with the support claw, so that the workpiece can be accurately positioned. Further, by pressing from above the heat sink with the pressing piece, the heat sink can be uniformly pressed against the casing. When packing is provided between the housing and the heat sink, the packing can be pressed with a uniform force. Accordingly, since the heat sink can be uniformly pressed against the housing, even if the screw tightening at one place is performed, the screw tightening portion at another place is prevented from being lifted and the heat sink is inclined. Therefore, even if the screw tightening is completed for each place, there is no variation in the screw tightening torque. In addition, retightening is unnecessary and machine cycle time can be shortened.

  By the way, in embodiment, although the structural example which screw-tightens the lid | cover (heat sink) which covers a housing | casing opening part was demonstrated, it is not only a housing | casing and a lid | cover, Can be applied similarly.

  In addition, the workpiece to be screwed is not limited to a workpiece placed on a carriage or an intermittent conveyance conveyor, but can also correspond to a workpiece on a continuous conveyance conveyor. In this case, the screw tightening unit can be moved in the same direction in synchronization with the moving workpiece, the workpiece is lifted from the conveyor during the movement, screw tightened, and the workpiece can be returned to the conveyor again to be applied to the automation line. .

  In addition, each operation | movement concerning the screw fastening method which the screw fastening apparatus demonstrated by each said embodiment performs computer (CPU etc.), such as target apparatus (said screw fastening apparatus), etc., for the control program prepared beforehand. Can be realized. This control program is recorded on a computer-readable recording medium such as a magnetic disk, an optical disk, or a USB (Universal Serial Bus) flash memory, and is executed by being read from the recording medium by the computer. The control program may be distributed via a network such as the Internet.

  The following additional notes are disclosed with respect to the embodiment described above.

(Supplementary note 1) a screw tightening unit having a screw tightening mechanism for tightening a work consisting of a housing and a lid, and a gripping mechanism for gripping the work;
An elevating mechanism for elevating and lowering the screw tightening unit in the direction of the workpiece;
A control unit that controls the device,
The control unit raises the screw tightening unit by the lifting mechanism and lifts the work from the mounting surface in a state where the work is gripped by the gripping mechanism, and thereby the horizontal surface of the work is lowered by the screw tightening unit. A screw tightening device that matches a horizontal plane and performs screw tightening by the screw tightening mechanism.

(Supplementary Note 2) The gripping mechanism has a support claw that engages with a protruding portion of the casing of the workpiece and supports the workpiece,
The screw tightening device according to appendix 1, wherein the projecting portion of the workpiece is engaged with the support claw by lifting the workpiece.

(Supplementary note 3) The screw fastening device according to supplementary note 2, wherein the gripping mechanism performs positioning in the horizontal plane direction by pressing the workpiece against a fixed block in the horizontal plane direction by movement of the movable block.

(Additional remark 4) The said raising / lowering mechanism is provided in the bottom part of the said screw fastening unit, and includes an elastic | stretchable elastic leg,
Any one of appendices 1 to 3, wherein the control unit causes the horizontal plane direction of the screw fastening unit to coincide with the horizontal plane direction of the workpiece by extending the telescopic leg and lifting the workpiece from the placement surface. The screw fastening apparatus as described in any one.

(Supplementary Note 5) The control unit retracts the support claw and the movable block from the work position when the screw tightening unit is lowered, and the support part is in a state where the projecting part of the work is positioned on the support claw. Addition 3 or 4 characterized by extending a nail | claw and the said movable block to the direction of the said workpiece | work, supporting the said workpiece | work on the said support nail | claw, and holding the said workpiece | work with the said movable block and the said fixed block. Screw tightening device.

(Supplementary Note 6) The screw tightening mechanism includes: an electric screwdriver for screwing a screw into a screw hole facing the height direction provided in the casing and the lid of the work; and the electric screwdriver at the screw hole portion. The screw fastening device according to any one of appendices 1 to 5, further comprising a three-axis moving mechanism that is freely movable.

(Supplementary note 7) The screw according to any one of supplementary notes 1 to 6, wherein the gripping mechanism includes a pressing portion that is extendable in a height direction for pressing the lid of the workpiece against the housing. Fastening device.

(Additional remark 8) The said workpiece | work is provided with packing between the said housing | casing and the said cover body,
The screw tightening device according to appendix 7, wherein the pressing portion of the gripping mechanism uniformly crushes the packing of the workpiece.

(Additional remark 9) After the said control part expands the said support nail | claw and the said movable block with the 1st pressing force in the direction of the said workpiece | work, and positions the protrusion part of the said workpiece | work on the said support nail | claw with the dead weight of the said workpiece | work Any one of Supplementary notes 2 to 8, wherein the movable block and the fixed block are gripped in the direction of the workpiece by a second pressing force that is stronger than the first pressing force. The described screw fastening device.

(Additional remark 10) The conveyor which conveys the said workpiece | work under the said screw fastening unit is arrange | positioned,
The screw tightening unit is movable in the conveying direction of the workpiece on the conveyor,
10. The screw tightening according to any one of appendices 1 to 9, wherein the control unit lifts the workpiece from the conveyor and performs screw tightening while moving the screw tightening unit in synchronization with the conveyor. apparatus.

(Additional remark 11) The said raising / lowering mechanism contains the wire which lifts the said screw fastening unit, and the motor which raises / lowers the said screw fastening unit by winding up the said wire, Any one of Additional remarks 1-10 characterized by the above-mentioned. The screw tightening device described in one.

(Additional remark 12) The said raising / lowering mechanism contains the some wire which lifts the said screw fastening unit, and the balancer which adjusts the said some wire length, and raises / lowers the said screw fastening unit, respectively. The screw fastening device according to any one of 10.

DESCRIPTION OF SYMBOLS 100 Screw fastening apparatus 102 Rail 103 Screw fastening unit 150 Car, conveyor 201 Case 202 Heat sink 203 Packing 211 Gutter part (protrusion part)
212, 221 Screw hole 222 Screw 301 Control unit 311 Robot control unit 312 Elevation control unit 313 Grip control unit 314 Screw tightening control unit 321 Elevating mechanism 323 Grip mechanism 325 Screw tightening mechanism 503 Motor 504 Pulley 505 Wire 506a Opening portion 512 Extendable leg 513 Supporting claw 514 Fixed block 515 Movable block 517 Pressing cylinder 525 Grasping cylinder 531 Three-axis actuator 532 Electric driver 801 Pressing piece 2501 Balancer W Workpiece

Claims (11)

A screw tightening unit having a screw tightening mechanism for tightening a work screw composed of a housing and a lid, and a gripping mechanism for gripping the work;
An elevating mechanism for elevating and lowering the screw tightening unit in the direction of the workpiece;
A control unit that controls the device,
The control unit raises the screw tightening unit by the lifting mechanism and lifts the work from the mounting surface in a state where the work is gripped by the gripping mechanism, and thereby the horizontal surface of the work is lowered by the screw tightening unit. A screw tightening device that matches a horizontal plane and performs screw tightening by the screw tightening mechanism. The gripping mechanism has a support claw that engages with a protruding portion of the casing of the workpiece and supports the workpiece,
The screw tightening device according to claim 1, wherein the workpiece protrusion is engaged with the projecting portion of the workpiece by lifting the workpiece.   3. The screw tightening device according to claim 2, wherein the gripping mechanism performs positioning in the horizontal plane direction by pressing the work against a fixed block in the horizontal plane direction by movement of the movable block. The elevating mechanism is provided at the bottom of the screw tightening unit and includes a telescopic leg that is telescopic,
The said control part makes the horizontal plane direction of the said screw fastening unit correspond with the horizontal plane direction of the said workpiece | work by extending the said expansion-contraction leg and lifting the said workpiece | work from a mounting surface, The horizontal plane direction of the said workpiece | work is characterized by the above-mentioned. The screw fastening apparatus as described in any one.   The control unit retracts the support claw and the movable block from the work position when the screw tightening unit is lowered, and the protrusion of the work is positioned on the support claw and the movable claw and the movable block. The screw tightening device according to claim 3 or 4, wherein a block is extended in a direction of the work, the work is supported on the support claw, and the work is gripped by the movable block and the fixed block. .   The screw tightening mechanism includes an electric screwdriver for screwing a screw into a screw hole facing the height direction provided in the casing and the lid of the work, and the electric screwdriver is movable to the screw hole portion. The screw tightening device according to claim 1, further comprising a triaxial moving mechanism.   The screw holding device according to any one of claims 1 to 6, wherein the gripping mechanism includes a pressing portion that is extendable and contractible in a height direction that presses the lid of the workpiece against the housing. The workpiece is provided with a packing between the casing and the lid,
The screw tightening device according to claim 7, wherein the pressing portion of the gripping mechanism uniformly crushes the packing of the workpiece.   The control unit extends the support claw and the movable block with a first pressing force in the direction of the work, positions the projecting part of the work on the support claw by the weight of the work, and then moves the movable block. The screw according to any one of claims 2 to 8, wherein the workpiece is gripped with a second pressing force that is stronger than the first pressing force in the direction of the workpiece. Fastening device. A conveyor that conveys the workpiece is disposed below the screw tightening unit,
The screw tightening unit is movable in the conveying direction of the workpiece on the conveyor,
The screw according to any one of claims 1 to 9, wherein the control unit performs screw tightening by lifting the workpiece from the conveyor while moving the screw tightening unit in synchronization with the conveyor. Fastening device.   The said raising / lowering mechanism contains the wire which lifts up the said screw fastening unit, and the motor which raises / lowers the said screw fastening unit by winding up the said wire, The Claim 1 characterized by the above-mentioned. Screw tightening device.

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